Machinable Long PVP-stabilized Silver Nanowires

Chemistry (Weinheim an Der Bergstrasse, Germany). Oct, 2004  |  Pubmed ID: 15372648

PVP-capped silver nanowires with a diameter range from 150 to 200 nm and a length range from 50 to 100 microm have been synthesized in large quantity by using a soft-template liquid-phase method. The so-obtained longer and thicker metallic nanowires exhibit fivefold-twinned structures bound by five [1 0 0] wall-planes and two spearlike ends around five [1 1 1] facets. X-ray photoelectron spectroscopy (XPS) investigations show that a strong interaction exists between the carboxyl oxygen atom (C=O) of PVP and the Ag core interface. The PVP-capped Ag nanowires can either self-assemble into ordered raft structures or form a complicated network, depending on the dispersive solvent employed. In addition, the Ag nanowires can also be specifically bent into various angles, demonstrating their excellent mechanical stability.

Large-scale Fabrication of Wafer-size Colloidal Crystals, Macroporous Polymers and Nanocomposites by Spin-coating

Journal of the American Chemical Society. Oct, 2004  |  Pubmed ID: 15493937

This paper reports a simple spin-coating technique for rapidly fabricating three types of technologically important materials--colloidal crystal, macroporous polymer, and polymeric nanocomposite, each with high crystalline qualities and wafer-scale sizes. Dispersion of monodisperse silica colloids in triacrylate monomers is spin-coated onto a variety of substrates. Shear-induced ordering and subsequent polymerization lead to the formation of three-dimensionally (3D) ordered colloidal crystals trapped inside a polymer matrix. The thickness of as-synthesized colloidal crystal-polymer nanocomposite is highly uniform and can be controlled simply by changing the spin speed and time. Selective removal of the polymer matrix and silica spheres lead to the formation of large-area colloidal crystals and macroporous polymers, respectively. The wafer-scale process is compatible with standard semiconductor microfabrication, as multiple micrometer-sized patterns can be created simultaneously for potential device applications. Normal-incidence transmission spectra in the visible and near-infrared regions show distinct peaks due to Bragg diffraction from 3D ordered structures. The spin-coating process opens a new route to the fundamental studies of shear-induced crystallization, melting and relaxation.

Surface-templated Nanostructured Films with Two-dimensional Ordered Arrays of Voids

Angewandte Chemie (International Ed. in English). Oct, 2004  |  Pubmed ID: 15495222

Wafer-scale Periodic Nanohole Arrays Templated from Two-dimensional Nonclose-packed Colloidal Crystals

Journal of the American Chemical Society. Mar, 2005  |  Pubmed ID: 15771501

This communication reports a simple yet versatile nonlithographic approach for fabricating wafer-scale periodic nanohole arrays from a large variety of functional materials, including metals, semiconductors, and dielectrics. Spin-coated two-dimensional (2D) nonclose-packed colloidal crystals are used as first-generation shadow masks during physical vapor deposition to produce isolated nanohole arrays. These regular nanoholes can then be used as second-generation etching masks to create submicrometer void arrays in the substrates underneath. Complex patterns with micrometer-scale resolution can be made by standard microfabrication techniques for potential device applications. These 2D-ordered nanohole arrays may find important technological applications ranging from subwavelength optics to interferometric biosensors.

Wafer-scale Fabrication of Periodic Polymer Attolitre Microvial Arrays

Chemical Communications (Cambridge, England). Apr, 2005  |  Pubmed ID: 15791303

Wafer-size periodic polymer attolitre microvial arrays of varying depth have been fabricated by templating from spin-coated 2D non-close-packed colloidal crystal-polymer nanocomposites.

PII Signal Transduction Proteins: Sensors of Alpha-ketoglutarate That Regulate Nitrogen Metabolism

Current Opinion in Microbiology. Apr, 2005  |  Pubmed ID: 15802248

PII proteins are small homotrimeric signal transduction proteins that regulate the activities of metabolic enzymes and permeases, and control the activities of signal transduction enzymes. The protein family shows high conservation, with examples in eukaryota (plants and eukaryotic algae), archaea, and bacteria. This distribution indicates that PII is one of the most ancient signalling proteins known.

Cloning and Characterization of Beta-carotene Ketolase Gene Promoter in Haematococcus Pluvialis

Acta Biochimica Et Biophysica Sinica. Apr, 2005  |  Pubmed ID: 15806294

The unicellular green alga Haematococcus pluvialis accumulates a highly valuable ketocarotenoid, astaxanthin, under various environmental stresses. beta-carotene ketolase (BKT) plays a key role in astaxanthin biosynthesis in H. pluvialis. In this paper, an approximate 700 bp 5'-flanking region of the bkt gene containing a putative promoter was cloned through walking upstream. The results of the sequence analysis showed that this bkt 5'-flanking region might have cis-acting elements such as sterol regulatory element (SRE-1)-like motifs, the C-repeat/dehydration responsive element (DRE) and al-3 proximal element (APE)-like motifs, except for typical TATA and CCAAT boxes. The results of the beta-galactosidase assay and the transient expression of lacZ driven by a series of sequential deletions revealed that a minimal promoter-like region might exist from -630 to -408 bp, and the highest promoter activity was observed to span the positions from -630 to -308 bp. The results of the site-directed mutagenesis of a C-repeat/DRE and two APE-like motifs in a promoter-like region (-630 to -308 bp) suggested that two APE-like motifs might be essential for transcriptional control of the bkt gene.

Effect of Dietary Supplementation of Chitosan and Galacto-mannan-oligosaccharide on Serum Parameters and the Insulin-like Growth Factor-I MRNA Expression in Early-weaned Piglets

Domestic Animal Endocrinology. May, 2005  |  Pubmed ID: 15826777

The study was to determine effects of dietary supplementation of chitosan (COS) and galacto-mannan-oligosaccharides (GMOS) on some serum biochemical indices, serum growth hormone (GH) and insulin-like growth factor-I (IGF-I) levels, and hepatic and long gissimus muscle IGF-I mRNA expression in early-weaned piglets. Twenty six Duroc x Landrace x Yorkshire piglets at the age of 15 days were used. The piglets had access to creep feed during the suckling. Six piglets were sacrificed for sampling at the beginning of the study. The other 20 piglets were individually housed in metabolic cages and randomly allotted to four corn and soybean meal-based diets including the control group, the antibiotic group with 110 mg lincomycin/kg diet, the COS group containing 0.025% COS, and the GMOS group with 0.20% GMOS, respectively, in a 2-week feeding experiment. Blood urea nitrogen (BUN) level was reduced whereas serum total protein concentration was increased (P<0.05) in responses to the COS and GMOS supplementation. Dietary supplementation of COS and GMOS also increased (P<0.05) the serum GH and IGF-I levels along with enhanced hepatic and the muscle IGF-I mRNA abundance. Dietary supplementation of oligosaccharides such as COS and GMOS may improve growth and feed conversion efficiency by increasing plasma GH and IGF-I levels, in the early-weaned piglets.

Transforming Kelp into a Marine Bioreactor

Trends in Biotechnology. May, 2005  |  Pubmed ID: 15866005

The past decade has seen the genetic engineering of various types of seaweed. To date, genetic transformation studies have been carried out in several seaweeds, including the red seaweeds Porphyra, Gracilaria, Grateloupia, Kappaphycus and Ceramium and the green seaweed Ulva. A genetic transformation model system has been established in the most commonly cultivated seaweed, the brown seaweed Laminaria japonica (kelp), based on the transfer of technology used in land plant transformation and also by modulating the seaweed life cycle. This model showed the potential for application of transgenic kelp to the production of valuable products and an indoor cultivation system for transgenic kelp was proposed, taking into account necessary factors for bio-safety. In this review, the establishment at use of the kelp transformation model is introduced, highlighting the potential for transforming kelp into a marine bioreactor.

[The Preparation, Structure Evaluation and Preliminary Application of Biomimetic Biphasic Calcium Phosphate Scaffold]

Zhonghua Wai Ke Za Zhi [Chinese Journal of Surgery]. Jun, 2005  |  Pubmed ID: 16083586

To fabricate biomimetic biphasic calcium phosphate BCP ceramic scaffolds using three-dimensional (3D) gel-lamination technology and evaluated their structure with 3D parameters and related method.

Establishment of a Micro-particle Bombardment Transformation System for Dunaliella Salina

Journal of Microbiology (Seoul, Korea). Aug, 2005  |  Pubmed ID: 16145551

In this study, we chronicle the establishment of a novel transformation system for the unicellular marine green alga, Dunaliella salina. We introduced the CaMV35S promoter-GUS construct into D. salina with a PDS1000/He micro-particle bombardment system. Forty eight h after transformation, via histochemical staining, we observed the transient expression of GUS in D. salina cells which had been bombarded under rupture-disc pressures of 450 psi and 900 psi. We observed no GUS activity in either the negative or the blank controls. Our findings indicated that the micro-particle bombardment method constituted a feasible approach to the genetic transformation of D. salina. We also conducted tests of the cells' sensitivity to seven antibiotics and one herbicide, and our results suggested that 20 microg/ml of Basta could inhibit cell growth completely. The bar gene, which encodes for phosphinothricin acetyltransferase and confers herbicide tolerance, was introduced into the cells via the above established method. The results of PCR and PCR-Southern blot analyses indicated that the gene was successfully integrated into the genome of the transformants.

New and One Pot Chemoselective Synthesis of Nucleoside 5'-H-phosphonate Diesters

Nucleosides, Nucleotides & Nucleic Acids. 2005  |  Pubmed ID: 16252669

Arbuzov reaction of phenyl phosphorodichloridite with two equiv of alcohol, or mixture of one equiv of alcohol and one equiv of tert-butyl alcohol led to the corresponding aryl H-phosphonate diesters. Following displacement of the H-phosphonate diesters with unprotected nucleosides chemoselectively produced nucleoside 5-H-phosphonate diesters in good yields, respectively.

Novel Link Between E2F1 and Smac/DIABLO: Proapoptotic Smac/DIABLO is Transcriptionally Upregulated by E2F1

Nucleic Acids Research. 2006  |  Pubmed ID: 16617145

Deregulated expression of E2F1 not only promotes S-phase entry but also induces apoptosis. Although it has been well documented that E2F1 is able to induce p53-dependent apoptosis via raising ARF activity, the mechanism by which E2F induces p53-independent apoptosis remains unclear. Here we report that E2F1 can directly bind to and activate the promoter of Smac/DIABLO, a mitochondrial proapoptotic gene, through the E2F1-binding sites BS2 (-542 approximately -535 bp) and BS3 (-200 approximately -193 bp). BS2 and BS3 appear to be utilized in combination rather than singly by E2F1 in activation of Smac/DIABLO. Activation of BS2 and BS3 are E2F1-specific, since neither E2F2 nor E2F3 is able to activate BS2 or BS3. Using the H1299 ER-E2F1 cell line where E2F1 activity can be conditionally induced, E2F1 has been shown to upregulate the Smac/DIABLO expression at both mRNA and protein levels upon 4-hydroxytamoxifen treatment, resulting in an enhanced mitochondria-mediated apoptosis. Reversely, reducing the Smac/DIABLO expression by RNA interference significantly diminishes apoptosis induced by E2F1. These results may suggest a novel mechanism by which E2F1 promotes p53-independent apoptosis through directly regulating its downstream mitochondrial apoptosis-inducing factors, such as Smac/DIABLO.

Large-scale Fabrication of Periodic Nanostructured Materials by Using Hexagonal Non-close-packed Colloidal Crystals As Templates

Langmuir : the ACS Journal of Surfaces and Colloids. Apr, 2006  |  Pubmed ID: 16618130

This letter reports a versatile nonlithographic technique for mass fabricating three types of technologically important materials-polymer microwell arrays, 2D-ordered magnetic nanodots, and semiconductor nanopillar arrays, each with high crystalline qualities and wafer-scale sizes. Spin-coated hexagonal non-close-packed silica colloidal crystals embedded in a polymer matrix are used as starting templates to create 2D polymeric microwell arrays. These through-hole arrays can then be used as second-generation templates to make periodic magnetic nanodots and semiconductor nanopillars. This self-assembly approach is compatible with standard semiconductor microfabrication, and complex micropatterns can be created for potential device applications. The wafer-scale technique may find important applications in biomicroanalysis, high-density magnetic recording media, and microphotonics.

[Endovascular Stent Implantation in Treatment of Intracranial Wide-necked Aneurysms]

Zhonghua Yi Xue Za Zhi. Jan, 2006  |  Pubmed ID: 16638317

To evaluate the effectiveness and feasibility of treatment of intracranial wide-necked aneurysms with a new technique of Neuroform self-expanding stent combined with detachable coil.

[Transvenous Embolization in Treatment of Refractory Carotid-cavernous Sinus Fistula]

Zhonghua Yi Xue Za Zhi. Apr, 2006  |  Pubmed ID: 16759509

To investigate the effects of transvenous embolization in treatment of refractory carotid-cavernous sinus fistula (CCF).

[Changes of Serum and Cerebrospinal Fluid Insulin-like Growth Factor-II Levels in Neonates with Hypoxic-ischemic Encephalopathy]

Zhongguo Dang Dai Er Ke Za Zhi = Chinese Journal of Contemporary Pediatrics. Jun, 2006  |  Pubmed ID: 16787587

Many studies have demonstrated that low levels of insulin-like growth factor-I (IGF-I) may be associated with the hypoxic-ischemic brain damage (HIBD) and that IGF-I has a neuroprotective effect. The role of IGF-II, a structurally and functionally homologous polypeptide with IGF-I, is unclear in HIBD. This study was designed to observe the changes of serum and cerebrospinal fluid (CSF) IGF-II levels in neonates with hypoxic-ischemic encephalopathy (HIE) and to investigate its effects on HIE.

[Influence and Mechanism of Peroxisome Proliferation Activated Receptor-alpha Expression Induced by WY14643 in Rat Lung with Acute Lung Injury]

Zhongguo Wei Zhong Bing Ji Jiu Yi Xue = Chinese Critical Care Medicine = Zhongguo Weizhongbing Jijiuyixue. Aug, 2006  |  Pubmed ID: 16887056

To investigate the effect of WY14643 [peroxisome proliferation activated receptor-alpha (PPAR-alpha) activator, 4-cholro-6-(2.3-xylidino)-2-pyrimidinylthio acetic acid] on PPAR-alpha expression in lung of acute lung injury (ALI) induced by lipopolysaccharide (LPS) and its mechanism.

Rotational Polymorphism in 2-naphthalenethiol SAMs on Au(111)

Journal of the American Chemical Society. Sep, 2006  |  Pubmed ID: 16984169

We evidence by STM that 2-naphthalenethiol self-assembled monolayers formed at the n-tetradecane/Au(111) interface coexist as two structural phases which both possess molecules into two different orientations (standing and lying). Such a rotational polymorphism is observed and understood at the molecular level for the first time.

The Bad Guy Cooperates with Good Cop P53: Bad is Transcriptionally Up-regulated by P53 and Forms a Bad/p53 Complex at the Mitochondria to Induce Apoptosis

Molecular and Cellular Biology. Dec, 2006  |  Pubmed ID: 17000778

Although the regulation of several Bcl-2 family molecules, including Puma, Noxa, Bax, and Bid, by p53 has been studied intensively, the interplay between Bad (Bcl-2 antagonist of cell death) and p53 has not yet been reported thus far. Here, we report that p53 activates Bad transcription and expression through binding to a short conserved sequence located approximately 6.6 kb upstream of the translation start point. We also demonstrate that Bad physically interacts with cytoplasmic p53, thereby preventing p53 from entering the nucleus and resulting in reduced transcription of Bad. Moreover, Bad is able to direct p53 to the mitochondria and forms a p53/Bad complex at the mitochondria. Two lines of evidences support this hypothesis: first, when mitochondria purified from p53-deficient H1299 cells are incubated with p53 and either wild-type (wt) Bad or mutant Bad (this mutant binds p53 yet is unable to migrate to mitochondria), p53 can be detected only in mitochondria incubated with wt Bad and not in those incubated with mutant Bad; second, knockdown of Bad expression reduces mitochondrial localization of p53. The mitochondrial p53/Bad complex promotes apoptosis via activation and oligomerization of Bak. Elimination of Bad expression by RNA interference notably attenuates apoptosis induced by etoposide. Hence, our collective data provide the first evidence that Bad plays dual roles in both p53 transcription-dependent and -independent pathways.

[Experimental Study of Recovery Force of Surface-modified TiNi Memory Alloy Rod]

Sheng Wu Yi Xue Gong Cheng Xue Za Zhi = Journal of Biomedical Engineering = Shengwu Yixue Gongchengxue Zazhi. Aug, 2006  |  Pubmed ID: 17002105

The recovery force of Ti-Nb coated and uncoated TiNi shape memory alloy rods was investigated. The rods were 6.0 mm, 6.5 mm and 7.0 mm in diameter respectively. The mean transition temperature was 33.0 degrees C. The rods were stored at -18 degrees C and pre-bent with a three-point bending fixture, the span was 20. 0 centimeters and the deflections were 5.0 mm, 10.0 mm, 15.0 mm and 20.0 mm, respectively. The rods were then heated in a constant temperature saline solution chamber. The experimental temperature was 37.0 C and 50.0 C respectively. The recovery force was measured in a constant displacement mode on biomaterial test machine. The results showed that the recovery force of the memory alloy rod increased with increasing recovery temperature, rod diameter and deformation of both Ti-Nb coated and uncoated surface. The recovery force of Ti-Nb coated rods of 6.0 and 6.5 millimeter in diameter was lower than the uncoated rods in the same diameter. However, the recovery force of 7.0-mm-diameter rods showed no significant difference between coated and uncoated surface.

[Endovascular Treatment of Posterior Cerebral Artery Aneurysm: Analysis of 21 Patients]

Zhonghua Yi Xue Za Zhi. Aug, 2006  |  Pubmed ID: 17064546

To investigate the effect of endovascular treatment on posterior cerebral artery (PCA) aneurysm.

[Studies on Preparation of Sustained-release Shuxiong Formulation, a Traditional Chinese Medicine Compound Recipe, Using Time-controlled Release Techniques]

Zhongguo Zhong Yao Za Zhi = Zhongguo Zhongyao Zazhi = China Journal of Chinese Materia Medica. Sep, 2006  |  Pubmed ID: 17087078

To prepare a sustained-release formulation of traditional Chinese medicine compound recipe by adopting time-controlled release techniques.

Effects of Hepatotrophic Factors on the Liver After Portacaval Shunt in Rats with Portal Hypertension

Chinese Medical Journal. Oct, 2006  |  Pubmed ID: 17097021

Portacaval shunt (PCS) prevent hepatotrophic factors from flowing into the liver, but they enter directly the systemic circulation and worsen liver injury. This study was designed to investigate the effects of hepatotrophic factors through the portal vein on the liver in rats with portal hypertension after portacaval shunt.

Poly(vinyl Pyrrolidone)-capped Five-fold Twinned Gold Particles with Sizes from Nanometres to Micrometres

Nanotechnology. Jul, 2006  |  Pubmed ID: 19661601

Poly(vinyl pyrrolidone)-capped multiple twinned gold (Au) particles with decahedral shape have been synthesized by a simple and convenient solvothermal wet chemical method. In the process, hydrogen tetrachloroauric acid (HAuCl(4).3H(2)O) was reduced by ethylene glycol (EG) to form the multiple twinned Au nanocrystals in the presence of poly(vinyl pyrrolidone) (PVP) molecules at 200 degrees C under the extra condition of autogenous pressure. The decahedral nanoparticles take up about 10% of the total amount and have the usual size distribution from several tens to hundreds of nanometres. Some larger microsized five-twinned Au particles with perfect decahedral shape have also been observed in the final product. Furthermore, x-ray photoelectron spectroscopy (XPS) measurements verified that PVP molecules are adsorbed on the surface of the Au particles. Based on the experimental results, a growth mechanism has been suggested to elucidate the formation of the small decahedral Au nanoparticles as well as their evolution into perfect large decahedral Au particles with the size of several micrometres.

Rectangular Nanostructuring of Au(111) Surfaces by Self-assembly of Size-selected Thiacrown Ether Macrocycles

Journal of the American Chemical Society. Mar, 2007  |  Pubmed ID: 17295492

Structure-function Analysis of Glutamine Synthetase Adenylyltransferase (ATase, EC 2.7.7.49) of Escherichia Coli

Biochemistry. Apr, 2007  |  Pubmed ID: 17355124

Glutamine synthetase adenylyltransferase (ATase) regulates the activity of glutamine synthetase by adenylylation and deadenylylation in response to signals of nitrogen and carbon status: glutamine, alpha-ketoglutarate, and the uridylylated and unmodified forms of the PII signal transduction protein. ATase consists of two conserved nucleotidyltransferase (NT) domains linked by a central region of approximately 200 amino acids. Here, we study the activities and regulation of mutated and truncated forms of ATase. Our results indicate the following. (i) The N-terminal NT domain contained the adenylyl-removing (AR) active site, and the C-terminal NT domain contained the adenylyltransferase (AT) active site. (ii) The enzyme contained a glutamine binding site, and glutamine increased the affinity for PII. (iii) The enzyme appeared to contain multiple sites for the binding of PII and PII-UMP. (iv) Truncated versions of ATase missing the C-terminal (NT) domain lacked both AT and AR activity, suggesting a role for the C-terminal NT domain in both activities. (v) The purified C-terminal NT domain and larger polypeptides containing this domain had significant basal AT activity, which was stimulated by glutamine. These polypeptides were indifferent to PII and PII-UMP, or their ATase activity was inhibited by either PII or PII-UMP. (vi) Certain point mutations in the central region or an internal deletion removing most of this part of the protein eliminated the AR activity and eliminated activation of the AT activity by PII, while not eliminating the binding of PII or PII-UMP. That is, these mutations in the central region appeared to destroy the communication between the PII and PII-UMP binding sites and the AT and AR active sites. (vii) Certain mutations in the central region of ATase appeared to dramatically improve the binding of glutamine to the enzyme. (viii) While the isolated AT and AR domains of ATase bound poorly to PII and PII-UMP, these domains bound PII and PII-UMP significantly better when linked to the central region of ATase. Together, our results indicate a highly coordinated enzyme, in which the AT and AR domains participate in each other's regulation and distant regulatory sites are in communication with each other. A model for the regulation of ATase by glutamine, PII, and PII-UMP consistent with all data is presented.

Escherichia Coli Glutamine Synthetase Adenylyltransferase (ATase, EC 2.7.7.49): Kinetic Characterization of Regulation by PII, PII-UMP, Glutamine, and Alpha-ketoglutarate

Biochemistry. Apr, 2007  |  Pubmed ID: 17355125

Glutamine synthetase adenylyltranferase (ATase, EC 2.7.7.49) catalyzes the adenylylation and deadenylylation of glutamine synthetase (GS), regulating GS activity. The adenylyltransferase (AT) reaction is activated by glutamine and by the unmodified form of the PII signal transduction protein and is inhibited by the uridylylated form of PII, PII-UMP. Conversely, the adenylyl-removing (AR) reaction is activated by PII-UMP and is inhibited by glutamine and by PII. Both AT and AR reactions are regulated by alpha-ketoglutarate, which binds to PII and PII-UMP. Here, we present a kinetic analysis of the AT and AR activities and their regulation. Both AT and AR reactions used a sequential mechanism of rapid equilibrium random binding of substrates and products. Activators and inhibitors had little effect on the binding of substrates, instead exerting their effects on catalysis. Our results were consistent with PII, PII-UMP, and glutamine shifting the enzyme among at least six different enzyme forms, two of which were inactive, one of which exhibited AR activity, and three of which exhibited AT activity. In addition to a site for glutamine, the enzyme appeared to contain two distinct sites for PII and PII-UMP. The PII, PII-UMP, and glutamine sites were in communication so that the apparent activation and inhibition constants for regulators depended upon each other. The binding of PII was favored by glutamine and its level reduced by PII-UMP, whereas glutamine and PII-UMP competed for the enzyme. alpha-Ketoglutarate, which acts exclusively through its binding to PII and PII-UMP, did not alter the binding of PII or PII-UMP to the enzyme. Rather, alpha-ketoglutarate dramatically affected the extent of activation or inhibition of the enzyme by PII or PII-UMP. A working hypothesis for the regulation of the AT and AR activities, consistent with all data, is presented.

P53 and Bad: Remote Strangers Become Close Friends

Cell Research. Apr, 2007  |  Pubmed ID: 17404594

RF-DYMHC: Detecting the Yeast Meiotic Recombination Hotspots and Coldspots by Random Forest Model Using Gapped Dinucleotide Composition Features

Nucleic Acids Research. Jul, 2007  |  Pubmed ID: 17478517

In the yeast, meiotic recombination is initiated by double-strand DNA breaks (DSBs) which occur at relatively high frequencies in some genomic regions (hotspots) and relatively low frequencies in others (coldspots). Although observations concerning individual hot/cold spots have given clues as to the mechanism of recombination initiation, the prediction of hot/cold spots from DNA sequence information is a challenging task. In this article, we introduce a random forest (RF) prediction model to detect recombination hot/cold spots from yeast genome. The out-of-bag (OOB) estimation of the model indicated that the RF classifier achieved high prediction performance with 82.05% total accuracy and 0.638 Mattew's correlation coefficient (MCC) value. Compared with an alternative machine-learning algorithm, support vector machine (SVM), the RF method outperforms it in both sensitivity and specificity. The prediction model is implemented as a web server (RF-DYMHC) and it is freely available at http://www.bioinf.seu.edu.cn/Recombination/rf_dymhc.htm. Given a yeast genome and prediction parameters (RI-value and non-overlapping window scan size), the program reports the predicted hot/cold spots and marks them in color.

Analysis of Synonymous Codon Usage in Aeropyrum Pernix K1 and Other Crenarchaeota Microorganisms

Journal of Genetics and Genomics = Yi Chuan Xue Bao. Mar, 2007  |  Pubmed ID: 17498625

In this study, a comparative analysis of the codon usage bias was performed in Aeropyrum pernix K1 and two other phylogenetically related Crenarchaeota microorganisms (i.e., Pyrobaculum aerophilum str. IM2 and Sulfolobus acidocaldarius DSM 639). The results indicated that the synonymous codon usage in A. pernix K1 was less biased, which was highly correlated with the GC(3S) value. The codon usage patterns were phylogenetically conserved among these Crenarchaeota microorganisms. Comparatively, it is the species function rather than the gene function that determines their gene codon usage patterns. A. pernix K1, P. aerophilum str. IM2, and S. acidocaldarius DSM 639 live in differently extreme conditions. It is presumed that the living environment played an important role in determining the codon usage pattern of these microorganisms. Besides, there was no strain-specific codon usage among these microorganisms. The extent of codon bias in A. pernix K1 and S. acidocaldarius DSM 639 were highly correlated with the gene expression level, but no such association was detected in P. aerophilum str. IM2 genomes.

Experimental Observation of Quantum Oscillation of Surface Chemical Reactivities

Proceedings of the National Academy of Sciences of the United States of America. May, 2007  |  Pubmed ID: 17517632

Here we present direct observation of a quantum reactivity with respect to the amounts of O(2) adsorbed and the rates of surface oxidation as a function of film thickness on ultrathin (2-6 nm) Pb mesas by scanning tunneling microscopy. Simultaneous spectroscopic measurements on the electronic structures reveal a quantum oscillation that originates from quantum well states of the mesas, as a generalization of the Fabry-Pérot modes of confined electron waves. We expect the quantum reactivity to be a general phenomenon for most ultrathin metal films with broad implications, such as nanostructure tuning of surface reactivities and rational design of heterogeneous catalysts.

MiPred: Classification of Real and Pseudo MicroRNA Precursors Using Random Forest Prediction Model with Combined Features

Nucleic Acids Research. Jul, 2007  |  Pubmed ID: 17553836

To distinguish the real pre-miRNAs from other hairpin sequences with similar stem-loops (pseudo pre-miRNAs), a hybrid feature which consists of local contiguous structure-sequence composition, minimum of free energy (MFE) of the secondary structure and P-value of randomization test is used. Besides, a novel machine-learning algorithm, random forest (RF), is introduced. The results suggest that our method predicts at 98.21% specificity and 95.09% sensitivity. When compared with the previous study, Triplet-SVM-classifier, our RF method was nearly 10% greater in total accuracy. Further analysis indicated that the improvement was due to both the combined features and the RF algorithm. The MiPred web server is available at http://www.bioinf.seu.edu.cn/miRNA/. Given a sequence, MiPred decides whether it is a pre-miRNA-like hairpin sequence or not. If the sequence is a pre-miRNA-like hairpin, the RF classifier will predict whether it is a real pre-miRNA or a pseudo one.

Generalized Fabrication of Two-dimensional Non-close-packed Colloidal Crystals

Langmuir : the ACS Journal of Surfaces and Colloids. Jul, 2007  |  Pubmed ID: 17571908

In this paper we report a generalized templating approach for fabricating wafer-scale, two-dimensional, non-close-packed (ncp) colloidal crystals. Polymer nanocomposites consisting of monolayer ncp colloidal crystals prepared by a spin-coating process are used as sacrificial templates. After removal of the colloidal silica templates, the voids in the polymer matrix are infiltrated with other materials. By plasma-etching the polymer matrix, wafer-scale ncp colloidal crystals from a variety of functional materials can be made. This technique is scalable and compatible with standard microfabrication. Two-component colloidal arrays with complex micropatterns can also be fabricated by combining microfabrication with this templating approach. Normal-incidence reflectivity spectra of replicated titania ncp arrays agree well with theoretical prediction using Scalar Wave Approximation.

RFRCDB-siRNA: Improved Design of SiRNAs by Random Forest Regression Model Coupled with Database Searching

Computer Methods and Programs in Biomedicine. Sep, 2007  |  Pubmed ID: 17644215

Although the observations concerning the factors which influence the siRNA efficacy give clues to the mechanism of RNAi, the quantitative prediction of the siRNA efficacy is still a challenge task. In this paper, we introduced a novel non-linear regression method: random forest regression (RFR), to quantitatively estimate siRNAs efficacy values. Compared with an alternative machine learning regression algorithm, support vector machine regression (SVR) and four other score-based algorithms [A. Reynolds, D. Leake, Q. Boese, S. Scaringe, W.S. Marshall, A. Khvorova, Rational siRNA design for RNA interference, Nat. Biotechnol. 22 (2004) 326-330; K. Ui-Tei, Y. Naito, F. Takahashi, T. Haraguchi, H. Ohki-Hamazaki, A. Juni, R. Ueda, K. Saigo, Guidelines for the selection of highly effective siRNA sequences for mammalian and chick RNA interference, Nucleic Acids Res. 32 (2004) 936-948; A.C. Hsieh, R. Bo, J. Manola, F. Vazquez, O. Bare, A. Khvorova, S. Scaringe, W.R. Sellers, A library of siRNA duplexes targeting the phosphoinositide 3-kinase pathway: determinants of gene silencing for use in cell-based screens, Nucleic Acids Res. 32 (2004) 893-901; M. Amarzguioui, H. Prydz, An algorithm for selection of functional siRNA sequences, Biochem. Biophys. Res. Commun. 316 (2004) 1050-1058) our RFR model achieved the best performance of all. A web-server, RFRCDB-siRNA (http://www.bioinf.seu.edu.cn/siRNA/index.htm), has been developed. RFRCDB-siRNA consists of two modules: a siRNA-centric database and a RFR prediction system. RFRCDB-siRNA works as follows: (1) Instead of directly predicting the gene silencing activity of siRNAs, the service takes these siRNAs as queries to search against the siRNA-centric database. The matched sequences with the exceeding the user defined functionality value threshold are kept. (2) The mismatched sequences are then processed into the RFR prediction system for further analysis.

Quercetin Subunit Specifically Reduces GlyR-mediated Current in Rat Hippocampal Neurons

Neuroscience. Aug, 2007  |  Pubmed ID: 17664043

Quercetin is a substance of low molecular weight found in vascular plants with a wide range of biological activities including antioxidative and anti-inflammatory activities. In the present study, the effects of quercetin on native glycine receptors (GlyRs) in cultured rat hippocampal neurons were investigated using a whole-cell patch-clamp technique. Quercetin reversibly and concentration-dependently depressed glycine-induced current (I(Gly)), with an IC50 of 10.7+/-0.24 microM and a Hill coefficient of 1.08+/-0.12. Quercetin depressed maximum I(Gly) and significantly changed the EC50 for glycine and the Hill coefficient. Kinetic analysis indicated that quercetin accelerated the rates of desensitization. Interestingly, after the end of glycine with quercetin coapplication, a transient rebound occurred. The quercetin effects also displayed voltage-dependence, being greater at positive membrane potentials. These effects suggested that quercetin may act as an open channel blocker. Furthermore, in the sequential application protocol, quercetin inhibited the peak amplitude of I(Gly) to a macroscopic degree while slowing GlyR desensitization. These effects implied that quercetin has a depressant effect independent of GlyR channel's opening, which maybe caused by an allosteric mechanism. Strikingly, quercetin inhibited the amplitude of recombinant-induced current mediated by alpha2-, alpha2beta-, alpha3- and alpha3beta-GlyRs but had no effects on alpha1- and alpha1beta-GlyRs that were expressed in HEK293T cells. We also investigated the effects of quercetin on I(Gly) in spinal neurons during development in vitro. The extent of blockade by quercetin on I(Gly) was slighter in spinal neurons than in hippocampal neurons in a development-dependent manner. Taken together, our results suggest that quercetin has possible effects in information processing within a neuronal network by inhibition of I(Gly) and may be useful as a pharmacological probe for identifying the subunit types of GlyRs.

Domain-swapped Dimerization of the Second PDZ Domain of ZO2 May Provide a Structural Basis for the Polymerization of Claudins

The Journal of Biological Chemistry. Dec, 2007  |  Pubmed ID: 17897942

Zonula occludens proteins (ZOs), including ZO1/2/3, are tight junction-associated proteins. Each of them contains three PDZ domains. It has been demonstrated that ZO1 can form either homodimers or heterodimers with ZO2 or ZO3 through the second PDZ domain. However, the underlying structural basis is not well understood. In this study, the solution structure of the second PDZ domain of ZO2 (ZO2-PDZ2) was determined using NMR spectroscopy. The results revealed a novel dimerization mode for PDZ domains via three-dimensional domain swapping, which can be generalized to homodimers of ZO1-PDZ2 or ZO3-PDZ2 and heterodimers of ZO1-PDZ2/ZO2-PDZ2 or ZO1-PDZ2/ZO3-PDZ2 due to high conservation between PDZ2 domains in ZO proteins. Furthermore, GST pulldown experiments and immunoprecipitation studies demonstrated that interactions between ZO1-PDZ2 and ZO2-PDZ2 and their self-associations indeed exist both in vitro and in vivo. Chemical cross-linking and dynamic laser light scattering experiments revealed that both ZO1-PDZ2 and ZO2-PDZ2 can form oligomers in solution. This PDZ domain-mediated oligomerization of ZOs may provide a structural basis for the polymerization of claudins, namely the formation of tight junctions.

Escherichia Coli PII Signal Transduction Protein Controlling Nitrogen Assimilation Acts As a Sensor of Adenylate Energy Charge in Vitro

Biochemistry. Nov, 2007  |  Pubmed ID: 17939683

PII signal transduction proteins are among the most widely distributed signaling proteins in nature, controlling nitrogen assimilation in organisms ranging from bacteria to higher plants. PII proteins integrate signals of cellular metabolic status and interact with and regulate receptors that are signal transduction enzymes or key metabolic enzymes. Prior work with Escherichia coli PII showed that all signal transduction functions of PII required ATP binding to PII and that ATP binding was synergistic with the binding of alpha-ketoglutarate to PII. Furthermore, alpha-ketoglutarate, a cellular signal of nitrogen and carbon status, was observed to strongly regulate PII functions. Here, we show that in reconstituted signal transduction systems, ADP had a dramatic effect on PII regulation of two E. coli PII receptors, ATase, and NRII (NtrB), and on PII uridylylation by the signal transducing UTase/UR. ADP acted antagonistically to alpha-ketoglutarate, that is, low adenylylate energy charge acted to diminish signaling of nitrogen limitation. By individually studying the interactions that occur in the reconstituted signal transduction systems, we observed that essentially all PII and PII-UMP interactions were influenced by ADP. Our experiments also suggest that under certain conditions, the three nucleotide binding sites of the PII trimer may be occupied by combinations of ATP and ADP. In the aggregate, our results show that PII proteins, in addition to serving as sensors of alpha-ketoglutarate, have the capacity to serve as direct sensors of the adenylylate energy charge.

DJ-1 Decreases Bax Expression Through Repressing P53 Transcriptional Activity

The Journal of Biological Chemistry. Feb, 2008  |  Pubmed ID: 18042550

DJ-1, originally identified as an oncogene product, is a protein with various functions in cellular transformation, oxidative stress response, and transcriptional regulation. Although previous studies suggest that DJ-1 is cytoprotective, the mechanism by which DJ-1 exerts its survival functions remains largely unknown. Here we show that DJ-1 exerts its cytoprotection through inhibiting p53-Bax-caspase pathway. DJ-1 interacts with p53 in vitro and in vivo. Overexpression of DJ-1 decreases the expression of Bax and inhibits caspase activation, whereas knockdown of DJ-1 increases Bax protein levels and accelerates caspase-3 activation and cell death induced by UV exposure. Our data provide evidence that the protective effects of DJ-1 on apoptosis are associated with its ability of decreasing Bax level through inhibiting p53 transcriptional activity.

Poly(N-vinyl-2-pyrrolidone) (PVP)-capped Dendritic Gold Nanoparticles by a One-step Hydrothermal Route and Their High SERS Effect

Langmuir : the ACS Journal of Surfaces and Colloids. Mar, 2008  |  Pubmed ID: 18225937

Dendritic gold (Au) nanoparticles have been successfully synthesized by the one-step hydrothermal reduction of HAuCl4.4H2O using ammonium formate (AF) as a reducing agent in the presence of PVP. Effects of different reactant concentrations on the morphologies of obtained products have been systematically investigated. On the basis of the morphologies of the products observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), it has been found that an excessive number of AF molecules are the origin of the dendritic Au particles besides PVP as a stabilizer. AF molecules serve not only as a reductant but probably also as a capping reagent. The study implies that the use of two or more capping reagents with different adsorption abilities will be beneficial to the formation of hyperbranched Au nanoparticles. The new finding will have the potential to be extended to the construction of other highly branched noble metal nanoparticles only by one-step synthesis. In addition, as an example, application of the dendritic particles as an active material in surface-enhanced Raman scattering has been investigated by employing 4-aminothiophenol molecules as a probe.

RISP: a Web-based Server for Prediction of RNA-binding Sites in Proteins

Computer Methods and Programs in Biomedicine. May, 2008  |  Pubmed ID: 18261823

Protein-RNA interactions play significant roles in a number of biological activities, such as protein synthesis, regulation of gene expression. Here we propose a hybrid RISP (RNA-interaction site prediction) method, using support vector machine (SVM) in conjunction with evolutionary information of amino acid sequences in terms of their position-specific scoring matrices (PSSMs) for prediction of RNA-binding sites. The results show that our RISP method has 72.2% net prediction (NP) (61.0% sensitivity and 83.3% specificity). When compared with previous studies, this novel method appears more accurate and better generalization abilities. RISP is freely available at http://grc.seu.edu.cn/RISP. Given a protein sequence, RISP decides whether residue in the protein is RNA-binding or not (optimal prediction), and gives the confidence value, 'high specificity' prediction and 'high sensitivity' prediction.

A Complex Cavernous Sinus Dural Arteriovenous Fistula Secondary to Covered Stent Placement for a Traumatic Carotid Artery-cavernous Sinus Fistula: Case Report

Journal of Neurosurgery. Mar, 2008  |  Pubmed ID: 18312107

Authors present the case of a patient with a direct carotid artery-cavernous sinus fistula caused by head trauma in whom a self-expanding covered stent was successfully used to obliterate the fistula. However, at the 9-month follow-up an angiogram revealed a complex caroticocavernous fistula that was completely obliterated with Onyx 18 transarterially.

A Cartilage ECM-derived 3-D Porous Acellular Matrix Scaffold for in Vivo Cartilage Tissue Engineering with PKH26-labeled Chondrogenic Bone Marrow-derived Mesenchymal Stem Cells

Biomaterials. May, 2008  |  Pubmed ID: 18313139

We developed a natural, acellular, 3-D interconnected porous scaffold derived from cartilage extracellular matrix (ECM). Human cartilage was physically shattered, then decellularized sequentially with use of hypotonic buffer, TritonX-100, and a nuclease solution and made into a suspension. The scaffold was fabricated by simple freeze-drying and cross-linking techniques. On histology, scaffolds showed most of the ECM components after removal of the cell fragments, and scanning electron microscopy revealed a 3-D interconnected porous structure. Cellular viability assay revealed no cytotoxic effects. In vitro study showed that the novel scaffold could provide a suitable 3-D environment to support the adheration, proliferation and differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) to chondrocytes in culture with chondrogenic medium after 21 days. Chondrogenically induced BMSCs labeled with fluorescent dye PKH26 were then grown on scaffolds and implanted subcutaneously into nude mice. Four weeks later, cartilage-like tissue formed, with positive staining for Safranin O, tuoluidine blue and collagen II. Cells in the samples seemed to confirm that they originated from the labeled BMSCs, as confirmed by in vivo fluorescent imaging and immunofluorescence examination. In conclusion, the cartilage ECM-derived porous scaffold shows potential as biomaterial for cartilage tissue engineering, and PKH26 fluorescent labeling and in vivo fluorescent imaging can be useful for cell tracking and analyzing cell-scaffold constructs in vivo.

Sumoylation is Critical for DJ-1 to Repress P53 Transcriptional Activity

FEBS Letters. Apr, 2008  |  Pubmed ID: 18339323

Sumoylation is an important post-translational modification, which is also involved in the pathogenesis of many neurodegenerative diseases. We previously reported that DJ-1 decreases Bcl-2 associated X protein expression through repressing p53 transcriptional activity. Here we show that DJ-1(K130R), the non-sumoylatable mutant form of DJ-1, shifts from nucleus to cytoplasm, fails to repress p53 transcriptional activity and loses its protective function against ultraviolet induced cell death. Our findings suggest that sumoylation is critical for DJ-1 to repress p53 transcriptional activity.

[Fabrication of a Novel Cartilage Acellular Matrix Scaffold for Cartilage Tissue Engineering]

Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi = Zhongguo Xiufu Chongjian Waike Zazhi = Chinese Journal of Reparative and Reconstructive Surgery. Mar, 2008  |  Pubmed ID: 18396722

To develop a novel cartilage acellular matrix (CACM) scaffold and to investigate its performance for cartilage tissue engineering.

Genome Evolution Trend of Common Carp (Cyprinus Carpio L.) As Revealed by the Analysis of Microsatellite Loci in a Gynogentic Family

Journal of Genetics and Genomics = Yi Chuan Xue Bao. Feb, 2008  |  Pubmed ID: 18407057

Genome evolution arises from two main ways of duplication and reduction. Fish specific genome duplication (FSGD) may have occurred before the radiation of the teleosts. Common carp (Cyprinus carpio L.) has been considered to be a tetraploid species, because of its chromosome numbers (2n=100) and its high DNA content. Using 69 microsatellite primer pairs, the variations were studied to better understand the genome evolution (genome duplication and diploidization) of common carp from a gynogenetic family. About 48% of primer pairs were estimated to amplify duplicates based on the number of PCR amplification per individual. Segregation patterns in the family suggested a partially duplicated genome structure and disomic inheritance. This indicates that the common carp is tetraploid and polyploidy occurred by allotetraploidy. Two primer pairs (HLJ021 and HLJ332) were estimated to amplify reduction based on the number of PCR amplification per individual. One allele in HLJ002 locus and HLJ332 locus was clearly lost in the gynogenetic family and the same as in six wild populations. Segregation patterns in the family suggested a partially diplodization genome structure. A hypothesis transition (dynamic) and equilibrium (static) were proposed to explain the common carp genome evolution between genome duplication and diploidization.

The Adsorption of O2 on Pb Films and the Effect of Quantum Modulation: a First-principles Prediction

The Journal of Chemical Physics. Apr, 2008  |  Pubmed ID: 18447477

Using first-principles calculations based on density-functional theory, we systematically study the adsorption of O(2) molecules on ultrathin Pb(111) films ranging from 3 to 11 monolayers (MLs). It is found that no matter how thick the film is, the O(2) molecule prefers to adsorb at the threefold hcp hollow site where it lies parallel to the surface. The adsorption mechanism is discussed from the hybridization of p orbitals of O(2) and Pb. The adsorption energy of O(2) on the Pb(111) film, about several hundred meV, shows a 2 ML oscillation with the thickness. This study well confirms the modulation of the surface reactivity of Pb films induced by the quantum well states, which is compatible with the previous experimental observation.

Quantum Size Effect Directed Selective Self-assembling of Cobalt Phthalocyanine on Pb(111) Thin Films

Journal of the American Chemical Society. Jun, 2008  |  Pubmed ID: 18510327

Adsorption and self-assembly of cobalt phthalocyanine (CoPc) molecules on Pb(111) thin films with a thickness ranging from 10 atomic monolayers (ML) to 20 ML were investigated by using scanning tunneling microscopy and spectroscopy (STM/STS). Unprecedented thickness-selective oscillating adsorption and self-assembly behavior of the molecules on the films were observed. STS measurement reveals that this oscillatory behavior arises from quantum size effect. The strong quantum confinement of electron motion in the Pb films modulates the electronic density of states at the Fermi level (DOS(EF)), leading to preferential adsorption at thicknesses of higher DOS(EF). The work provides an unambiguous evidence for quantum modulation of surface reactivities of a metal thin film.

Templated Fabrication of Sub-100 Nm Periodic Nanostructures

Chemical Communications (Cambridge, England). Jul, 2008  |  Pubmed ID: 18594729

Periodic polymer nanoposts and metal nanohole arrays with tunable size have been fabricated by templating from spin-coated two-dimensional non close-packed colloidal crystal-polymer nanocomposites.

Effects of Local Release of Hepatocyte Growth Factor on Peripheral Nerve Regeneration in Acellular Nerve Grafts

Experimental Neurology. Nov, 2008  |  Pubmed ID: 18680744

Options for reconstructing peripheral nerve gaps after trauma are limited. The acellular nerve is a new kind of biomaterial used to reconstruct the peripheral nerve defect, but its use could be improved upon. We aimed to investigate the effect of adenoviral transfection with hepatocyte growth factor (HGF) on the functional recovery of transected sciatic nerves repaired by acellular nerve grafting. 30 Rats were divided into three groups (10/group) for autografting and acellular grafting, as well as acellular grafting with adenovirus transfection of HGF (1 x 10(8) pfu) injected in muscles around the proximal and distal allograft coapation. Sciatic functional index (SFI) was evaluated every 4 weeks to week 16 by measuring rat footprints on walking-track testing. The three groups presented initial complete functional loss, followed by slow but steady recovery, with final similar SFIs. Weight of the gastrocnemius and soleus muscles, histologic and morphometric study and neovascularization in the nerve grafts were evaluated at week 16. Autografting gave the best functional recovery, but HGF-treated acellular grafting gave better recovery than acellular grafting alone. Neovascularization was greater with HGF-treated acellular grafting than with autografting and acellular grafting alone. Axonal regeneration distance of autografting on the 20th postoperative day was the longest in the three groups,while that of acellular grafting alone was the smallest. Acellular nerve grafting may be useful for functional peripheral nerve regeneration, and with human HGF gene transfection may improve on acellular grafting alone in functional recovery.

Biomimetic Subwavelength Antireflective Gratings on GaAs

Optics Letters. Oct, 2008  |  Pubmed ID: 18830359

We have developed a simple and scalable bottom-up approach for fabricating moth-eye antireflective coatings on GaAs substrates. Monolayer, non-close-packed silica colloidal crystals are created on crystalline GaAs wafers by a spin-coating-based single-layer reduction technique. These colloidal monolayers can be used as etching masks during a BCl(3) dry-etch process to generate subwavelength-structured antireflective gratings directly on GaAs substrates. The gratings exhibit excellent broadband antireflective properties, and the specular reflection matches with the theoretical prediction using a rigorous coupled-wave analysis model. These bioinspired antireflection coatings have important technological applications ranging from efficient solar cells to IR detectors.

[Expression of Mechano-growth Factor in Escherichia Coli and Activity Analysis]

Sheng Wu Gong Cheng Xue Bao = Chinese Journal of Biotechnology. Jul, 2008  |  Pubmed ID: 18837392

Mechano-growth factor (MGF) is one of IGF-1 isoforms. MGF is mechanosensitive and has important functions in muscle hypertrophy, regeneration and nerve injury recovery. In this study, MGF cDNA (330 bp) was cloned from stretched osteoblasts by RT-PCR. In order to avoid prolin residue inhibiting enterokinase cleavage, 9bp of MGF cDNA 5' end sequence was truncated by primer, then the obtained truncated MGF (des(1-3)MGF) cDNA (321 bp) was subcloned in pET32a(+) vector to construct a prokaryotic recombination expression plasmid. Trx/des(1-3)MGF fusion protein, existing in forms of solution, was expressed in transformed Escherichia coli strain BL21(DE3) by IPTG induction at 30 degres C. The supernatant of cell lysates was subjected to ion exchange chromatography and Ni2+ metal affinity chromatography, and the fusion protein was obtained with the purity over 95%. After the fusion protein was cleaved by enterokinase, Trx and des(1-3)MGF was isolated by reverse-phase HPLC. Through these procedures, des(1-3) MGF was obtained with the purity of 98%. The protein molecular mass was conformity to the theoretical value by SDS-PAGE and mass spectrometry analysis. The purified des(1-3)MGF was incubated with MC3T3-E1 for cell proliferation and migration assays. The results show that des(1-3)MGF exhibited more facilitative effects on proliferation and migration of MC3T3-E1 than that of des(1-3)IGF-1.

Diverse Splicing Patterns of Exonized Alu Elements in Human Tissues

PLoS Genetics. 2008  |  Pubmed ID: 18841251

Exonization of Alu elements is a major mechanism for birth of new exons in primate genomes. Prior analyses of expressed sequence tags show that almost all Alu-derived exons are alternatively spliced, and the vast majority of these exons have low transcript inclusion levels. In this work, we provide genomic and experimental evidence for diverse splicing patterns of exonized Alu elements in human tissues. Using Exon array data of 330 Alu-derived exons in 11 human tissues and detailed RT-PCR analyses of 38 exons, we show that some Alu-derived exons are constitutively spliced in a broad range of human tissues, and some display strong tissue-specific switch in their transcript inclusion levels. Most of such exons are derived from ancient Alu elements in the genome. In SEPN1, mutations of which are linked to a form of congenital muscular dystrophy, the muscle-specific inclusion of an Alu-derived exon may be important for regulating SEPN1 activity in muscle. Realtime qPCR analysis of this SEPN1 exon in macaque and chimpanzee tissues indicates human-specific increase in its transcript inclusion level and muscle specificity after the divergence of humans and chimpanzees. Our results imply that some Alu exonization events may have acquired adaptive benefits during the evolution of primate transcriptomes.

A-type GABA Receptor As a Central Target of TRPM8 Agonist Menthol

PloS One. 2008  |  Pubmed ID: 18852885

Menthol is a widely-used cooling and flavoring agent derived from mint leaves. In the peripheral nervous system, menthol regulates sensory transduction by activating TRPM8 channels residing specifically in primary sensory neurons. Although behavioral studies have implicated menthol actions in the brain, no direct central target of menthol has been identified. Here we show that menthol reduces the excitation of rat hippocampal neurons in culture and suppresses the epileptic activity induced by pentylenetetrazole injection and electrical kindling in vivo. We found menthol not only enhanced the currents induced by low concentrations of GABA but also directly activated GABA(A) receptor (GABA(A)R) in hippocampal neurons in culture. Furthermore, in the CA1 region of rat hippocampal slices, menthol enhanced tonic GABAergic inhibition although phasic GABAergic inhibition was unaffected. Finally, the structure-effect relationship of menthol indicated that hydroxyl plays a critical role in menthol enhancement of tonic GABA(A)R. Our results thus reveal a novel cellular mechanism that may underlie the ambivalent perception and psychophysical effects of menthol and underscore the importance of tonic inhibition by GABA(A)Rs in regulating neuronal activity.

[The Protective Effects and Mechanisms of Peroxisome Proliferator-activated Receptor-gamma Agonist in Rats with Acute Lung Injury]

Zhonghua Jie He He Hu Xi Za Zhi = Zhonghua Jiehe He Huxi Zazhi = Chinese Journal of Tuberculosis and Respiratory Diseases. Jun, 2008  |  Pubmed ID: 19031802

To observe if peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonist (troglitazone) was able to alleviate lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats, and explore the underlying mechanisms.

[Effect of Controlled Release Nerve Growth Factor on Repairing Peripheral Nerve Defect by Acellular Nerve Graft]

Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi = Zhongguo Xiufu Chongjian Waike Zazhi = Chinese Journal of Reparative and Reconstructive Surgery. Nov, 2008  |  Pubmed ID: 19068610

To explore the effect of controlled release of nerve growth factor (NGF) on peripheral nerve defect repaire by acellular nerve graft.

Recombinant Expression of Rt-PA Gene (encoding Reteplase) in Gametophytes of the Seaweed Laminaria Japonica (Laminariales, Phaeophyta)

Science in China. Series C, Life Sciences / Chinese Academy of Sciences. Dec, 2008  |  Pubmed ID: 19093086

The life cycle of seaweed Laminaria japonica involves a generation alternation between diploid sporophyte and haploid gametophte. The expression of foreign genes in sporophte has been proved. In this research, the recombinant expression in gametophyte was investigated by particle bombardment with the rt-PA gene encoding the recombinant human tissue-type plasminogen activator (Reteplase), which is a thrombolytic agent for acute myocardial infarction (AMI). Transgenic gametophytes were selected by their resistance to herbicide phosphiothricin (PPT), and proliferated in an established bubble column photo-bioreactor. According to the results from quantitative ELISA, Southern blotting, and fibrin agarose plate assay (FAPA) for bioactivity, it was showed that the rt-PA gene had been integrated into the genome of gametophytes of L. japonica, and the expression product showed the expected bioactivity, implying the proper post-transcript modification in haploid gametophyte.

3,7-Dihydr-oxy-3,7-diphenyl-2H,6H-pyrrolo[3,4-f]isoindole-1,5(3H,7H)-dione Methanol Disolvate

Acta Crystallographica. Section E, Structure Reports Online. 2008  |  Pubmed ID: 21581444

The asymmetric unit of the title compound, C(22)H(16)N(2)O(4)·2CH(4)O, contains one half-mol-ecule and a methanol solvent mol-ecule. The aromatic ring is oriented at a dihedral angle of 82.91 (3)° with respect to the planar indole ring systems. In the crystal structure, inter-molecular O-H⋯O and N-H⋯O hydrogen bonds link the mol-ecules into chains along the b axis.

Zinc Oxide Nanostructures: Epitaxially Growing from Hexagonal Zinc Nanostructures

Nanotechnology. Nov, 2008  |  Pubmed ID: 21832752

The epitaxial growth of ZnO nanosheets and nanoneedles from a Zn/ZnO core/shell structure is verified by an experiment in which the ZnO nanoneedles and nanosheets are synthesized in air within an ultra-low temperature range from 250 to 400 °C by thermal oxidation of Zn films made up of hexagonal nanodiscs or nanoprisms. The hexagonal Zn structures are oxidized to form a Zn/ZnO core/shell structure with an epitaxial relationship; ZnO nanoneedles and nanosheets are found to grow epitaxially from the ZnO shell, along sixfold symmetric [Formula: see text] directions, showing the same lattice orientation as the Zn core. The stability difference among different facets of hexagonal Zn crystal structures plays a key role in the formation of ZnO nanosheets, nanoneedles and the Zn/ZnO core/shell structure, as well as ZnO hollow structures. A vapor-solid mechanism is suggested to explain the epitaxial growth process of the ZnO products. Photoluminescence properties of the ZnO nanostructures are also explored.

Large-scale Assembly of Colloidal Nanoparticles and Fabrication of Periodic Subwavelength Structures

Nanotechnology. Nov, 2008  |  Pubmed ID: 21836279

This paper reports a simple and scalable spin-coating technique for assembling 70 nm silica nanoparticles into non-close-packed colloidal crystals over a large area. The thickness of the shear-aligned colloidal crystals can be controlled from hundreds of layers to a single monolayer by adjusting the spin-coating conditions. We further demonstrate that the spin-coated colloidal monolayers can be used as structural templates to pattern sub-100 nm pillar arrays directly on silicon substrates. The resulting subwavelength-structured pillar arrays exhibit excellent broadband antireflective and superhydrophobic properties, which are promising for developing self-cleaning antireflection coatings for crystalline silicon solar cells. This bottom-up approach enables large-scale production of periodic nanostructures with resolution beyond the optical diffraction limit that have important technological applications ranging from high-density data storage and optoelectronics to biological sensing and subwavelength optics.

Grayscale Photomask Fabricated by Laser Direct Writing in Metallic Nano-films

Optics Express. Oct, 2009  |  Pubmed ID: 19997222

The grayscale photomask plays a key role in grayscale lithography for creating 3D microstructures like micro-optical elements and MEMS structures, but how to fabricate grayscale masks in a cost-effective way is still a big challenge. Here we present novel low cost grayscale masks created in a two-step method by laser direct writing on Sn nano-films, which demonstrate continuous-tone gray levels depended on writing powers. The mechanism of the gray levels is due to the coexistence of the metal and the oxides formed in a laser-induced thermal process. The photomasks reveal good technical properties in fabricating 3D microstructures for practical applications.

[Analysis of Deafness Gene Mutations by Gene Chip and Its Clinical Significance]

Lin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi = Journal of Clinical Otorhinolaryngology, Head, and Neck Surgery. Nov, 2009  |  Pubmed ID: 20359100

To analyze deafness gene mutations by genechip.

Effects of Ramelteon and Triazolam in a Mouse Genetic Model of Early Morning Awakenings

Brain Research. Nov, 2009  |  Pubmed ID: 19664610

The onset of the daily wheel running bout precedes dark onset by several hours in the early runner genetic variant of mice. Here, we test the hypothesis that timed daily administration of a melatonin agonist, ramelteon, or a benzodiazepine, triazolam, normalizes the timing of daily wheel-running rhythms in early runner mice. The daily profiles of wheel-running activity of early runner mice were monitored continuously in a 12:12 light/dark cycle. Wheel running was assessed before, during and after timed daily oral administration of saline vehicle (n=12), ramelteon (10 mg/kg, n=12), or triazolam (1 mg/kg, n=12). The timing of wheel-running rhythms relative to the light/dark cycle was used as a measure of the timing of wake onset. Under baseline conditions, early runner mice entrained to a light/dark cycle at an advanced phase, approximately 3 h before dark onset, on average. Triazolam, but not ramelteon, suppressed wheel-running acutely when administered just prior to the time at which wheel-running onset had occurred under baseline conditions. On a washout day under a light/dark cycle subsequent to one week of once daily administration, the onset of wheel-running was delayed relative to baseline in both ramelteon-treated mice and triazolam-treated mice. In constant dark subsequent to a second week of once daily administration, the onset of wheel-running activity was not affected by either compound. Thus, ramelteon and triazolam caused a shift in the timing of wheel-running rhythms in an LD cycle but did so without long-term effects on the functioning of the circadian clock.

Ion Segregation and Deliquescence of Alkali Halide Nanocrystals on SiO2

The Journal of Physical Chemistry. A. Sep, 2009  |  Pubmed ID: 19708692

The adsorption of water on alkali halide (KBr, KCl, KF, NaCl) nanocrystals on SiO2 and their deliquescence was investigated as a function of relative humidity (RH) from 8% to near saturation by scanning polarization force microscopy. At low humidity, water adsorption solvates ions at the surface of the crystals and increases their mobility. This results in a large increase in the dielectric constant, which is manifested in an increase in the electrostatic force and in an increase in the apparent height of the nanocrystals. Above 58% RH, the diffusion of ions leads to Ostwald ripening, where larger nanocrystals grow at the expense of the smaller ones. At the deliquescence point, droplets were formed. For KBr, KCl, and NaCl, the droplets exhibit a negative surface potential relative to the surrounding region, which is indicative of the preferential segregation of anions to the air/solution interface.

Several Interleukin-4 and Interleukin-13 Gene Single Nucleotide Polymorphisms Among Chinese Asthmatic Patients

Allergy and Asthma Proceedings : the Official Journal of Regional and State Allergy Societies. Jul-Aug, 2009  |  Pubmed ID: 19772762

Asthma is a common respiratory disease associated with airway hyperactivity and high total serum immunoglobulin E (IgE) levels. The asthmatic phenotypes are widely considered to be caused by environmental effects on genetically predisposed individuals. Interleukin (IL)-4 and IL-13 act on B cells and regulate the IgE production, and the single nucleotide polymorphisms (SNPs) in the IL-4 and IL-13 genes are implicated in the pathogenesis of asthma. To study the association of IL-4 and IL-13 gene polymorphisms with asthma, we sequenced the promoter regions and exons of IL-4 and IL-13 genes in two groups: one (spouses group) consisted of 13 pairs of asthmatic patients (cases) and their unaffected spouses (controls); the other (parents group) consisted of 11 pairs of asthmatic children (cases) and their unaffected father/mother (controls). In total, seven polymorphisms were identified, one novel and six previously reported. However, according to the results of the statistical analysis we performed, no statistically significant association of these SNPs and asthma was observed (p > 0.05). Asthma is largely determined by the accumulation of several certain genetic variations other than one or two SNPs. Future function studies may be able to help us reveal the significance of genetic variants we identified in this study.

Modulated Self-assembly of 4,4'-diphenyltetrathiafulvalene Molecules on Highly Oriented Pyrolytic Graphite by N-tetradecane Solvent

Nanotechnology. Oct, 2009  |  Pubmed ID: 19779244

We report the formation of a binary-component self-assembled monolayer (SAM) comprising 4,4'-diphenyltetrathiafulvalene (DP-TTF) and n-tetradecane (n-C(14)H(30)) molecules with periodic strip-like phase separation structures on a highly oriented pyrolytic graphite (HOPG) surface. Scanning tunneling microscopy (STM) imaging reveals that ordered DP-TTF single- and double-lamella are periodically tuned by ordered n- C(14)H(30) single- and double-lamella, respectively. This finding can be qualitatively understood in terms of a phase field model, in which the interplay of three ingredients, including free energy of the binary-component solution monolayer, phase boundary energy and surface stress, determines the final equilibrium sizes of the ordered DP-TTF and n- C(14)H(30) phases in the binary-component SAM. Furthermore, anisotropy of the surface stress breaks the symmetry of the substrate and causes the n- C(14)H(30) molecules to arrange along preferential substrate 010 directions. The orientation of the n-C(14)H(30) molecule stripes further guides the directions of the DP-TTF lamellar structures. In addition, scanning tunneling spectra (STS) of the individual DP-TTF and n- C(14)H(30) molecules in the ordered monolayer show a remarkable difference in I(V) curves on the HOPG substrate.

Alpha-ketoglutarate Controls the Ability of the Escherichia Coli PII Signal Transduction Protein to Regulate the Activities of NRII (NrB but Does Not Control the Binding of PII to NRII

Biochemistry. Dec, 2009  |  Pubmed ID: 19877669

PII signal transduction proteins are among the most widely distributed signaling proteins in nature; these proteins are direct sensors of alpha-ketoglutarate and adenylylate energy charge and control receptors that are signal transduction proteins, metabolic enzymes, or permeases involved in nitrogen metabolism. Prior studies showed that alpha-ketoglutarate regulated the ability of PII to control the activities of glutamine synthetase adenylyltransferase (ATase) but did not affect the ability of PII to bind to ATase. Here, we show that a similar pattern of alpha-ketoglutarate regulation was obtained with another PII receptor, the two-component system transmitter protein NRII (NtrB). Although alpha-ketoglutarate was required for the binding of PII to NRII, PII bound to NRII equally well as the concentration of alpha-ketoglutarate was varied through its physiological range. Variation of the concentration of alpha-ketoglutarate through its physiological range provided dramatic regulation of the ability of PII to activate the phosphatase activity of NRII and controlled the ability of PII to inhibit the autophosphorylation of NRII. Thus, PII control of NRII activities could be dissected into distinct binding and regulation steps, and when present in its physiological concentration range, alpha-ketoglutarate apparently played a role in only the latter step.

Sensation and Signaling of Alpha-ketoglutarate and Adenylylate Energy Charge by the Escherichia Coli PII Signal Transduction Protein Require Cooperation of the Three Ligand-binding Sites Within the PII Trimer

Biochemistry. Dec, 2009  |  Pubmed ID: 19877670

PII proteins are sensors of alpha-ketoglutarate and adenylylate energy charge that regulate signal transduction proteins, metabolic enzymes, and permeases involved in nitrogen assimilation. Here, purified Escherichia coli PII and two of its receptors, ATase and NRII, were used to study the mechanisms of sensation by PII. We assembled heterotrimeric forms of PII from wild-type and mutant subunits, which allowed us to assess the role of the three binding sites for alpha-ketoglutarate and adenylylate nucleotide in the PII trimer. Signaling of alpha-ketoglutarate and adenylylate energy charge by these heterotrimeric PII proteins required multiple binding sites for these effectors, and the ligand-binding sites on different subunits could influence the function of a single subunit interacting with a receptor, implying communication between PII subunits. Wild-type and heterotrimeric forms of PII were also used to examine the effects of alpha-ketoglutarate and ADP on PII activation of the adenylyltransferase (AT) activity of ATase. Previous work showed that when ATP was the sole adenylylate nucleotide, alpha-ketoglutarate controlled the extent of PII activation but did not alter the PII activation constant (K(act)). We show that ADP affected both the PII K(act) and the extent of activation by PII. When ATP was present, ADP dramatically reduced the K(act) for wild-type PII, and this effect was antagonized by alpha-ketoglutarate. Consequently, when ATP was present, the antagonism between ADP and alpha-ketoglutarate allowed each of these effectors to influence the PII K(act) for activation of ATase. A study of heterotrimeric forms of PII suggested that the major part of the ability of ADP to improve the binding of PII to ATase required multiple nucleotide binding sites and intersubunit communication. We also used nondenaturing gel electrophoresis to investigate the effect of ADP and alpha-ketoglutarate on the binding of PII to ATase and NRII. These studies showed that ATase and NRII differ in their requirements for interaction with PII, and that under the appropriate conditions, the antagonism between alpha-ketoglutarate and ADP allowed each of these effectors to influence the binding of PII to receptors.

Apoptosis of Human Burkitt's Lymphoma Cells Induced by 2-N,N-diethylaminocarbonyloxymethyl-1-diphenylmethyl-4-(3,4,5-trimethoxybenzoyl) Piperazine Hydrochloride (PMS-1077)

Archives of Pharmacal Research. Dec, 2009  |  Pubmed ID: 20162401

Piperazine is one of the heterocycles which are associated with diverse pharmacological activities. 2-N,N-Diethylaminocarbonyloxymethyl-1-diphenylmethyl-4-(3,4,5-trimethoxybenzoyl) piperazine hydrochloride (PMS-1077) is a trisubstituted piperazine which contains a trimethoxybenzene ring and a benzhydrylpiperazine fragment, both of which can induce cell proliferation regression by different mechanisms. We have therefore examined the effects of PMS-1077 on Human Burkitt's lymphoma cells (Raji). The viability of Raji cells was determined by MTT assay and also assessed by trypan blue dye exclusion method. The results demonstrate that PMS-1077 can suppress the proliferation of Raji cells in a dose- and timedependent manner, while inhibit colony formation ability of Raji cells merely in a dose-dependent manner in vitro. Meanwhile, morphological changes were observed using fluorescence microscope. Flow cytometric analysis through PI stains showed that PMS-1077 blocked the growth of Raji cells in the G(0)/G(1) period, and induced apoptosis of Raji cells after 48 h of incubation. Cell apoptosis induced by PMS-1077 was further confirmed by staining with Annexin-V FITC and PI. Preliminary study by molecular docking suggests that PMS-1077 may inhibit tubulin polymerization. More experiments are in progress in our laboratory to reveal the mode of action of PMS-1077 in the induction of apoptosis of Raji cells.

Reconstitution of Escherichia Coli Glutamine Synthetase Adenylyltransferase from N-terminal and C-terminal Fragments of the Enzyme

Biochemistry. Jan, 2009  |  Pubmed ID: 19105634

ATase brings about the short-term regulation of glutamine synthetase (GS) by catalyzing the adenylylation and deadenylylation of GS in response to signals of cellular nitrogen status and energy. The adenylyltransferase (AT) activity of ATase is activated by glutamine and by the unmodified form of the PII signal transduction protein and is inhibited by PII-UMP. Conversely, the adenylyl-removing (AR) activity of ATase is activated by PII-UMP and inhibited by unmodified PII and by glutamine. Here, we show that the enzyme can be reconstituted from two purified polypeptides that comprise the N-terminal two-thirds of the protein and the C-terminal one-third of the protein. Properties of the reconstituted enzyme support recent hypotheses for the sites of regulatory interactions and mechanisms for intramolecular signal transduction. Specifically, our results are consistent with the protein activators (PII and PII-UMP) binding to the enzyme domain with the opposing activity, with intramolecular signal transduction by direct interactions between the N-terminal AR catalytic domain and the C-terminal AT catalytic domain. Similarly, glutamine inhibition of the AR activity involved intramolecular signaling between the AT and AR domains. Finally, our results are consistent with the hypothesis that the AR activity of the N-terminal domain required activation by the opposing C-terminal (AT) domain.

Glycine Receptor in Rat Hippocampal and Spinal Cord Neurons As a Molecular Target for Rapid Actions of 17-beta-estradiol

Molecular Pain. 2009  |  Pubmed ID: 19138413

Glycine receptors (GlyRs) play important roles in regulating hippocampal neural network activity and spinal nociception. Here we show that, in cultured rat hippocampal (HIP) and spinal dorsal horn (SDH) neurons, 17-beta-estradiol (E2) rapidly and reversibly reduced the peak amplitude of whole-cell glycine-activated currents (IGly). In outside-out membrane patches from HIP neurons devoid of nuclei, E2 similarly inhibited IGly, suggesting a non-genomic characteristic. Moreover, the E2 effect on IGly persisted in the presence of the calcium chelator BAPTA, the protein kinase inhibitor staurosporine, the classical ER (i.e. ERalpha and ERbeta) antagonist tamoxifen, or the G-protein modulators, favoring a direct action of E2 on GlyRs. In HEK293 cells expressing various combinations of GlyR subunits, E2 only affected the IGly in cells expressing alpha2, alpha2beta or alpha3beta subunits, suggesting that either alpha2-containing or alpha3beta-GlyRs mediate the E2 effect observed in neurons. Furthermore, E2 inhibited the GlyR-mediated tonic current in pyramidal neurons of HIP CA1 region, where abundant GlyR alpha2 subunit is expressed. We suggest that the neuronal GlyR is a novel molecular target of E2 which directly inhibits the function of GlyRs in the HIP and SDH regions. This finding may shed new light on premenstrual dysphoric disorder and the gender differences in pain sensation at the CNS level.

Donor-pi-acceptor Structure Between Ag Nanoparticles and Azobenzene Chromophore and Its Enhanced Third-order Optical Non-linearity

Dalton Transactions (Cambridge, England : 2003). Feb, 2009  |  Pubmed ID: 19156276

An amorphous silica hybrid film containing covalently linked azobenzene chromophores and Ag nanoparticles was synthesized by a one-step sol-gel route in the presence of amino trialkoxysilane (APTES). The electron transfer from the N-containing groups in the APTES and azobenzene molecules, which are chemisorbed onto the surface of Ag nanoaprticles, makes the Ag nanoparticles negatively charged. Subsequently, a new D-pi-A electron structure between the Ag nanoparticles and the N-containing groups/azobenzene chromophores is created. The enhanced internal electric field in the nanoparticles and the strengthened and extended pi-conjugation in the new D-pi-A electron structure, lead to the large enhancement of optical non-linearity of the hybrid films.

Characterization and Anti-tumor Activity of Alkali-extracted Polysaccharide from Enteromorpha Intestinalis

International Immunopharmacology. Mar, 2009  |  Pubmed ID: 19159698

The polysaccharide DAEB was isolated and purified from Enteromorpha intestinalis. It consisted of rhamnose, xylose, galactose, and glucose in a molar ratio of 5.36:1.00:0.57:0.64, and had a molecular weight of 46.8 kDa. Mice were treated with three doses of DAEB for 10 consecutive days by oral administration, the tumor inhibition was 61.17%, 67.65% and 70.59% at doses of 100, 200 and 400 mg/kg, respectively. However, no direct cytotoxicity was detected. At dose of 100, 200 and 400 mg/kg, a significant increase (P<0.01) in relative spleen and thymus weight, and production of tumor necrosis factor alpha (TNF-alpha) were observed in DAEB treated groups. We also found that DAEB significantly stimulated lymphocyte proliferation, especially Concanavalin A-induced lymphocyte proliferation in a dose-dependent manner, and augmented phagocytosis and secretion of NO and TNF-alpha in peritoneal macrophages. The results indicated that DAEB had potent anti-tumor activity which may be associated with its potent immunostimulating effect.

[Vascular Endothelial Growth Factor Receptor-1 Activation Induces Epithelial to Mesenchmal Transition in Hepatocellular Carcinoma Cell Line MHCC97-H.]

Zhonghua Gan Zang Bing Za Zhi = Zhonghua Ganzangbing Zazhi = Chinese Journal of Hepatology. Feb, 2009  |  Pubmed ID: 19254458

To evaluate the mechanism of increased invasion and migration of hepatocellular carcinoma (HCC) cells induced by vascular endothelial growth factor receptor-1 (VEGFR-1) activation.

Improvement of Peripheral Nerve Regeneration in Acellular Nerve Grafts with Local Release of Nerve Growth Factor

Microsurgery. 2009  |  Pubmed ID: 19296502

Previous studies have demonstrated the potential of growth factors in peripheral nerve regeneration. A method was developed for sustained delivery of nerve growth factor (NGF) for nerve repair with acellular nerve grafts to augment peripheral nerve regeneration. NGF-containing polymeric microspheres were fixed with fibrin glue around chemically extracted acellular nerve grafts for prolonged, site-specific delivery of NGF. A total of 52 Wistar rats were randomly divided into four groups for treatment: autografting, NGF-treated acellular grafting, acellular grafting alone, and acellular grafting with fibrin glue. The model of a 10-mm sciatic nerve with a 10-mm gap was used to assess nerve regeneration. At the 2nd week after nerve repair, the length of axonal regeneration was longer with NGF-treated acellular grafting than acellular grafting alone and acellular grafting with fibrin glue, but shorter than autografting (P < 0.05). Sixteen weeks after nerve repair, nerve regeneration was assessed functionally and histomorphometrically. The percentage tension of the triceps surae muscles in the autograft group was 85.33 +/- 5.59%, significantly higher than that of NGF-treated group, acellular graft group and fibrin-glue group, at 69.79 +/- 5.31%, 64.46 +/- 8.48%, and 63.35 +/- 6.40%, respectively (P < 0.05). The ratio of conserved muscle-mass was greater in the NGF-treated group (53.73 +/- 4.56%) than in the acellular graft (46.37 +/- 5.68%) and fibrin glue groups (45.78 +/- 7.14%) but lower than in the autograft group (62.54 +/- 8.25%) (P < 0.05). Image analysis on histological observation revealed axonal diameter, axon number, and myelin thickness better with NGF-treated acellular grafting than with acellular grafting alone and acellular grafting with fibrin glue (P < 0.05). There were no significant differences between NGF-treated acellular grafting and autografting. This method of sustained site-specific delivery of NGF can enhance peripheral nerve regeneration across short nerve gaps repaired with acellular nerve grafts.

STM Imaging Ortho- and Para-fluorothiophenol Self-assembled Monolayers on Au(111)

Langmuir : the ACS Journal of Surfaces and Colloids. May, 2009  |  Pubmed ID: 19320427

Self-assembled monolayers (SAMs) of para- and ortho-fluorothiophenol (p- and o-FTP) spontaneously formed on Au(111) substrate have been contrasted through investigation by a scanning tunneling microscope (STM) at room temperature. High-resolution STM imaging reveals that p-FTP adopts a 6 x radical3R30 degrees molecule arrangement containing six molecules. Two different kinds of p-FTP molecule dimer line structures have been formed on Au(111) by intermolecular pi-pi stacking along 112 substrate directions, besides a single p-FTP molecule line. In contrast, o-FTP molecules self-assemble into a much looser wave-like SAM, which can be described as a 5 x 3 radical3R30 degrees structure containing two molecules. Periodic density functional theory (DFT) calculations for the two systems suggest that these kinds of FTP molecules preferentially take the asymmetrical positions between 3-fold face-centered cubic (fcc) hollow and bridge sites on Au(111), tilting from the substrate surface. Theoretical simulation gives apparent average tilted angles of 58 degrees and 68 degrees for p-FTP and o-FTP with respect to the surface normal, respectively. This simulation shows that o-FTP is more inclined to lie down toward the Au(111) surface compared to p-FTP. The difference between p-FTP and o-FTP SAM structures can be qualitatively understood in terms of the variation of intermolecular dipole-dipole orientation. This suggests that, besides well-known Au-S and pi-pi interactions, electrostatic interactions including dipole-dipole, quadrupole-quadrupole, and dipole-quadrupole interactions might also play an important role in influencing the SAM structures formed by aromatic thiols with a permanent dipole moment.

Large-scale Analysis of Exonized Mammalian-wide Interspersed Repeats in Primate Genomes

Human Molecular Genetics. Jun, 2009  |  Pubmed ID: 19324900

Transposable elements (TEs) are major sources of new exons in higher eukaryotes. Almost half of the human genome is derived from TEs, and many types of TEs have the potential to exonize. In this work, we conducted a large-scale analysis of human exons derived from mammalian-wide interspersed repeats (MIRs), a class of old TEs which was active prior to the radiation of placental mammals. Using exon array data of 328 MIR-derived exons and RT-PCR analysis of 39 exons in 10 tissues, we identified 15 constitutively spliced MIR exons, and 15 MIR exons with tissue-specific shift in splicing patterns. Analysis of RNAs from multiple species suggests that the splicing events of many strongly included MIR exons have been established before the divergence of primates and rodents, while a small percentage result from recent exonization during primate evolution. Interestingly, exon array data suggest substantially higher splicing activities of MIR exons when compared with exons derived from Alu elements, a class of primate-specific retrotransposons. This appears to be a universal difference between exons derived from young and old TEs, as it is also observed when comparing Alu exons to exons derived from LINE1 and LINE2, two other groups of old TEs. Together, this study significantly expands current knowledge about exonization of TEs. Our data imply that with sufficient evolutionary time, numerous new exons could evolve beyond the evolutionary intermediate state and contribute functional novelties to modern mammalian genomes.

Alcohol Consumption Might Be Beneficial for the Patients with Resectable Liver Cancer Due to Its Induction of Tolerance to the Ischemia-reperfusion Injury

Medical Hypotheses. Aug, 2009  |  Pubmed ID: 19332364

Up to now, curative hepatectomy remains the best treatment for patients with liver cancer, during which ischemia/reperfusion injuries of the liver is inevitable. While the ischemia/reperfusion is a major cause of morbidity and mortality in patients undergone hepatectomy and transplantation, so how to reduce it to an acceptable level and to enhance the tolerance of liver to ischemia/reperfusion injury seem to be an eternal challenge for the hepatobiliary surgeon. Considering the broad protective effect of alcohol, we rationally proposed that the protection induced by ethanol consumption might take place without creature species limitation and without organ specific. To our interests, the liver is the most important place where the alcohol mainly metabolized in our body. The metabolic process of alcohol subsequently induces oxidative stress and inflammatory reaction to the liver. If it simulates the same effect as it acts on other organs, alcohol consumption might be advantageous to the liver undergone subsequent ischemia/reperfusion injuries. Since we are not trying to cure diseases occurring only in rats, the likely relevance of human liver injury should be carefully considered. To adequately evaluate our hypothesis that ethanol preconditioning before liver surgery may do good for the patients due to its induction of the tolerance of the liver to ischemia and reperfusion injuries, at least two studies need to be performed in future. The objective is to find out a simple and effective method to prevent the ischemia/reperfusion injuries during hepatectomy as well as other liver surgery and improve the perioperative outcome of the affected patients. Whether alcohol consumption can protect the liver ischemia/reperfusion injuries both from animals to human, or can only take effect in experiments, or neither of them? All these questions might be answered by the presumed studies. Of course, it would be more useful to testify the true effects of ethanol preconditioning in a clinical situation.

Surface-enhanced Raman Scattering on Periodic Metal Nanotips with Tunable Sharpness

Nanotechnology. Jun, 2009  |  Pubmed ID: 19433880

This paper reports on a scalable bottom-up technology for producing periodic gold nanotips with tunable sharpness as surface-enhanced Raman scattering (SERS) substrates. Inverted silicon pyramidal pits, which are templated from non-close-packed colloidal crystals prepared by a spin-coating technology, are used as structural templates to replicate arrays of polymer nanopyramids with nanoscale sharp tips. The deposition of a thin layer of gold on the polymer nanopyramids leads to the formation of SERS-active substrates with a high enhancement factor (up to 10(8)). The thickness of the deposited metal determines the sharpness of the nanotips and the resulting Raman enhancement factor. Finite-element electromagnetic modeling shows that the nanotips can significantly enhance the local electromagnetic field and the sharpness of nanotips greatly affects the SERS enhancement.

Using High-density Exon Arrays to Profile Gene Expression in Closely Related Species

Nucleic Acids Research. Jul, 2009  |  Pubmed ID: 19474342

Global comparisons of gene expression profiles between species provide significant insight into gene regulation, evolutionary processes and disease mechanisms. In this work, we describe a flexible and intuitive approach for global expression profiling of closely related species, using high-density exon arrays designed for a single reference genome. The high-density probe coverage of exon arrays allows us to select identical sets of perfect-match probes to measure expression levels of orthologous genes. This eliminates a serious confounding factor in probe affinity effects of species-specific microarray probes, and enables direct comparisons of estimated expression indexes across species. Using a newly designed Affymetrix exon array, with eight probes per exon for approximately 315,000 exons in the human genome, we conducted expression profiling in corresponding tissues from humans, chimpanzees and rhesus macaques. Quantitative real-time PCR analysis of differentially expressed candidate genes is highly concordant with microarray data, yielding a validation rate of 21/22 for human versus chimpanzee differences, and 11/11 for human versus rhesus differences. This method has the potential to greatly facilitate biomedical and evolutionary studies of gene expression in nonhuman primates and can be easily extended to expression array design and comparative analysis of other animals and plants.

Analysis of the Constituents in Rat Plasma After Oral Administration of Shexiang Baoxin Pill by HPLC-ESI-MS/MS

Biomedical Chromatography : BMC. Dec, 2009  |  Pubmed ID: 19517427

A valid method using liquid chromatography coupled with electrospray ionization (ESI) and ion trap mass spectrometry was established for the study of the absorbed components in rat plasma after oral administration of a traditional Chinese medicine (TCM) Shexiang Baoxin pill. The plasma was deproteinated by adding methanol prior to liquid chromatography, in which separation was carried out on a Symmetry C(18) column (5 microm, 250 x 4.6 mm). A linear gradient with 0.5% formic acid-water-acetonitrile was used as mobile phase. Mass spectra were acquired in both negative and positive modes. Twenty-one components including 17 components from Shexiang Baoxin pill and four metabolites were observed from a comprehensive analysis of the chromatography of Shexiang Baoxin pill, controlled plasma and dosed plasma. All of the 17 prototype compounds and three of the metabolites were identified by comparing their retention behaviors and MS and MS/MS spectra with reference compounds and literature data. This study developed an integrated method for screening the bioactive constituents in plasma after oral adminstration of Chinese herbal medicine and provided helpful chemical information for further pharmacology and active mechanism research on TCM.

The Shape Evolution of Gold Seeds and Gold@silver Core-shell Nanostructures

Nanotechnology. Jul, 2009  |  Pubmed ID: 19584416

We report the seed-dependent shape evolution of gold@silver (Au@Ag) core-shell nanostructures with various morphologies through using pre-existing Au nanocrystals as nuclei in a polyvinylpyrrolidone (PVP)-assisted polyol reduction process. Au nanocrystalline seeds with different shapes such as cube, truncated-octahedron, octahedron, twinned hexagon and triangle, five-twinned decahedron and nanorod are firstly synthesized by refluxing a 1,5-pentanediol solution containing Au precursors in the presence of PVP. The Au seeds obtained in this way then serve as the nuclei for further epitaxial growth of Ag shells by using Ag precursors via the same route. Scanning transmission electron microscope (STEM) characterization of the products obtained demonstrates that the morphological evolution of the Ag shells depends completely on the shapes of the Au seeds that are used. We have observed that the Au@Ag core-shell nanostructures formed with various regular shapes such as cube, bi-triangle, and nanorod with five-twinned cross section, are mostly surrounded by {100}-type Ag crystalline facets. Our findings provide new evidence and clear evolution routines from the Au cores with well-defined shapes to the corresponding Ag shells for the Au@Ag core-shell nanostructures by the family of the PVP-assisted polyol reduction methods.

Sensitivity and Optimization of Artificial Digestion in the Inspection of Meat for Trichinella Spiralis

Foodborne Pathogens and Disease. Aug, 2010  |  Pubmed ID: 20524897

In many countries, the method of choice in inspecting meat for Trichinella spiralis infection is artificial digestion. We conducted a study of the sensitivity of the artificial digestion method recommended by the International Commission on Trichinellosis for detecting T. spiralis larvae in meat and of the effect of modifications of some procedures used in the method on its sensitivity. As part of this, we evaluated the effects on larval recovery of the vessels used for larval settling, sieve sizes, and temperatures at which larvae passed through the sieves, using larvae from T. spiralis-infected mice. We observed the effects on larval recovery of digestion duration and of modified artificial digestion by using 10-g samples of infected mouse muscle alone or mixed with uninfected pork. The percentages of larvae recovered with the respective use of separatory funnels and conical cylinders were 51.20% and 98.70%. The rates of recovery of T. spiralis larvae at 4 degrees C after passage through sieves of 425-microm mesh (No. 40), 250-microm mesh (No. 60), and 180-microm mesh (No. 80) were 98.42%, 90.59%, and 81.63%, which exceeded the 97.79%, 85.10%, and 61.12% rates of recovery of motile larvae at 40 degrees C and the 95.12%, 78.60%, and 44.16% rates of recovery of dead larvae at 90 degrees C. The larval recovery rate after digestion for 2 hours (96.18%) was greater than that after 0.5 hours (88.00%). We then examined a modified digestion method in which 10-g samples of pork mixed with 300 mL of digestive solution were digested for 2 hours at 43 degrees C followed by chilling of digest solution to 4 degrees C before passing it through a 425-microm mesh (No. 40) sieve and allowing it to settle in a 1-L conical cylinder. With this procedure, the modified method detected T. spiralis in samples of pork meat weighing 10 g and containing either 1 larva per gram or 0.1 larva per gram. Further validation of digestion method incorporating these modifications is required with the use of larger samples of infected muscle from species such as swine, which are routinely tested for T. spiralis for the purpose of food safety.

Inhibitory Effects of Lang-du Extract on the in Vitro and in Vivo Growth of Melanoma Cells and Its Molecular Mechanisms of Action

Cytotechnology. Aug, 2010  |  Pubmed ID: 20607395

The purpose of this study is to investigate the effects of Lang-du extract (LDE) from Traditional Chinese Medicine (TCM) Euphorbia fischeriana Steud on the in vitro and in vivo growth of melanoma cells and its molecular mechanisms of action. Our present results have shown that LDE significantly suppressed the in vitro melanoma cell growth in dose- and time-dependent manners. LDE also displayed the synergistic effect with γ-radiation on the reduction of the cell viability in melanoma cells. The animal experimental results further confirmed that compared with the control group without drug treatment, the tumor volume in mice was significantly and time-dependently less in LDE group. The absolute weight of solid tumor in the LDE group was 7-fold lower than that in the control group. Western blot analysis indicated that LDE markedly down-regulated the expression of anti-apoptotic protein Bcl-2 and up-regulated the level of pro-apoptotic protein Bax, eventually leading the reduction of Bcl-2/Bax protein ratios both in the cultured melanoma cells and in the tumors from melanoma-bearing mice. In addition, LDE significantly reduced the tumor progression-associated protein levels of vascular endothelial growth factor (VEGF), hepatocyte growth factor/scatter factor (HGF/SF), and osteopontin (OPN) in tumors from the LDE-treated mice. Our findings suggest that LDE may have a wide therapeutic and/or adjuvant therapeutic application in the treatment of melanoma and other cancer.

[Functional Evaluation of Chemically Extracted Acellular Nerve Allograft Supplement with Different Tissues of Schwann Cells for Peripheral Nerve Regeneration]

Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi = Zhongguo Xiufu Chongjian Waike Zazhi = Chinese Journal of Reparative and Reconstructive Surgery. Nov, 2010  |  Pubmed ID: 21226345

To construct chemically extracted acellular nerve allograft (CEANA) with Schwann cells (SCs) from different tissues and to compare the effect of repairing peripheral nerve defect.

[Experimental Study on Promotion of Neurotropic Reinnervation with Chemically Extracted Acellular Nerve Allograft]

Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi = Zhongguo Xiufu Chongjian Waike Zazhi = Chinese Journal of Reparative and Reconstructive Surgery. Nov, 2010  |  Pubmed ID: 21226346

To investigate the promotion effect of neurotropic reinnervation with chemically extracted acellular nerve allograft.

Electrophysiological Properties of Human Induced Pluripotent Stem Cells

American Journal of Physiology. Cell Physiology. Mar, 2010  |  Pubmed ID: 19955484

Human embryonic stem cells (hESCs) can self-renew while maintaining their pluripotency. Direct reprogramming of adult somatic cells to induced pluripotent stem cells (iPSCs) has been reported. Although hESCs and human iPSCs have been shown to share a number of similarities, such basic properties as the electrophysiology of iPSCs have not been explored. Previously, we reported that several specialized ion channels are functionally expressed in hESCs. Using transcriptomic analyses as a guide, we observed tetraethylammonium (TEA)-sensitive (IC(50) = 3.3 +/- 2.7 mM) delayed rectifier K(+) currents (I(KDR)) in 105 of 110 single iPSCs (15.4 +/- 0.9 pF). I(KDR) in iPSCs displayed a current density of 7.6 +/- 3.8 pA/pF at +40 mV. The voltage for 50% activation (V(1/2)) was -7.9 +/- 2.0 mV, slope factor k = 9.1 +/- 1.5. However, Ca(2+)-activated K(+) current (I(KCa)), hyperpolarization-activated pacemaker current (I(f)), and voltage-gated sodium channel (Na(V)) and voltage-gated calcium channel (Ca(V)) currents could not be measured. TEA inhibited iPSC proliferation (EC(50) = 7.8 +/- 1.2 mM) and viability (EC(50) = 5.5 +/- 1.0 mM). By contrast, 4-aminopyridine (4-AP) inhibited viability (EC(50) = 4.5 +/- 0.5 mM) but had less effect on proliferation (EC(50) = 0.9 +/- 0.5 mM). Cell cycle analysis further revealed that K(+) channel blockers inhibited proliferation primarily by arresting the mitotic phase. TEA and 4-AP had no effect on iPSC differentiation as gauged by ability to form embryoid bodies and expression of germ layer markers after induction of differentiation. Neither iberiotoxin nor apamin had any function effects, consistent with the lack of I(KCa) in iPSCs. Our results reveal further differences and similarities between human iPSCs and hESCs. A better understanding of the basic biology of iPSCs may facilitate their ultimate clinical application.

Na+/Ca2+ Exchanger is a Determinant of Excitation-contraction Coupling in Human Embryonic Stem Cell-derived Ventricular Cardiomyocytes

Stem Cells and Development. Jun, 2010  |  Pubmed ID: 19719399

In adult cardiomyocytes (CMs), the Na(+)/Ca(2+) exchanger (NCX) is a well-defined determinant of Ca(2+) homeostasis. Developmentally, global NCX knockout in mice leads to abnormal myofibrillar organization, electrical defects, and early embryonic death. Little is known about the expression and function of NCX in human heart development. Self-renewable, pluripotent human embryonic stem cells (hESCs) can serve as an excellent experimental model. However, hESC-derived CMs are highly heterogeneous. A stably lentivirus-transduced hESC line (MLC2v-dsRed) was generated to express dsRed under the transcriptional control of the ventricular-restricted myosin light chain-2v (MLC2v) promoter. Electrophysiologically, dsRed+ cells differentiated from MLC2vdsRed hESCs displayed ventricular action potentials (AP), exclusively. Neither atrial nor pacemaker APs were observed. While I(Ca-L), I(f), and I(Kr) were robustly expressed, I(Ks) and I(K1) were absent in dsRed+ ventricular hESCCMs. Upon differentiation (7+40 to +90 days), the basal [Ca(2+)](i), Ca(2+) transient amplitude, maximum upstroke, and decay velocities significantly increased (P < 0.05). The I(Ca-L) antagonizer nifedipine (1 microM) decreased the Ca(2+) transient amplitude (to approximately 30%) and slowed the kinetics (by approximately 2-fold), but Ca(2+) transients could still be elicited even after complete ICa-L blockade, suggesting the presence of additional Ca(2+) influx(es). Indeed, Ni(2+)-sensitive INCX could be recorded in 7+40- and +90-day dsRed+ hESC-CMs, and its densities increased from -1.2 +/- 0.6 pA/pF at -120 mV and 3.6 +/- 1.0 pA/pF at 60 mV by 6- and 2-folds, respectively. With higher [Ca(2+)](i), 7+90-day ventricular hESC-CMs spontaneously but irregularly fired transients upon a single stimulus under an external Na(+)-free condition; however, without extracellular Na(+), nifedipine could completely inhibit Ca(2+) transients. We conclude that I(NCX) is functionally expressed in developing ventricular hESC-CMs and contributes to their excitation-contraction coupling.

Methyl Jasmonate- or Gibberellins A3-induced Astaxanthin Accumulation is Associated with Up-regulation of Transcription of Beta-carotene Ketolase Genes (bkts) in Microalga Haematococcus Pluvialis

Bioresource Technology. Aug, 2010  |  Pubmed ID: 20403692

The microalga Haematococcus pluvialis accumulates astaxanthin in response to abiotic stresses. Since methyl jasmonate (MJ) and gibberellins A(3) (GA(3)) are involved in the stress responses of plants, the impact of these compounds on astaxanthin metabolism was studied. Alga cells treated separately with MJ and GA(3) accumulated more astaxanthin than the controls. MJ and GA(3) treatment increased the transcription of three beta-carotene ketolase genes (bkts). MJ- and GA(3)-responsive cis-acting elements were identified in the 5'-flanking regions of bkt genes. These results suggest that MJ and GA(3) constitute molecular signals in the network of astaxanthin accumulation. Induction of astaxanthin accumulation by MJ or GA(3) without any other stimuli presents an attractive application potential.

Evolution of Alternative Splicing in Primate Brain Transcriptomes

Human Molecular Genetics. Aug, 2010  |  Pubmed ID: 20460271

Alternative splicing is a predominant form of gene regulation in higher eukaryotes. The evolution of alternative splicing provides an important mechanism for the acquisition of novel gene functions. In this work, we carried out a genome-wide phylogenetic survey of lineage-specific splicing patterns in the primate brain, via high-density exon junction array profiling of brain transcriptomes of humans, chimpanzees and rhesus macaques. We identified 509 genes showing splicing differences among these species. RT-PCR analysis of 40 exons confirmed the predicted splicing evolution of 33 exons. Of these 33 exons, outgroup analysis using rhesus macaques confirmed 13 exons with human-specific increase or decrease in transcript inclusion levels after humans diverged from chimpanzees. Some of the human-specific brain splicing patterns disrupt domains critical for protein-protein interactions, and some modulate translational efficiency of their host genes. Strikingly, for exons showing splicing differences across species, we observed a significant increase in the rate of silent substitutions within exons, coupled with accelerated sequence divergence in flanking introns. This indicates that evolution of cis-regulatory signals is a major contributor to the emergence of human-specific splicing patterns. In one gene (MAGOH), using minigene reporter assays, we demonstrated that the combination of two human-specific cis-sequence changes created its human-specific splicing pattern. Together, our data reveal widespread human-specific changes of alternative splicing in the brain and suggest an important role of splicing in the evolution of neuronal gene regulation and functions.

Signaling Properties of a Covalent Modification Cycle Are Altered by a Downstream Target

Proceedings of the National Academy of Sciences of the United States of America. Jun, 2010  |  Pubmed ID: 20479260

We used a model system of purified components to explore the effects of a downstream target on the signaling properties of a covalent modification cycle, an example of retroactivity. In the experimental system used, a bifunctional enzyme catalyzed the modification and demodification of its substrate protein, with both activities regulated by a small molecule stimulus. Here we examined how a downstream target for one or both forms of the substrate of the covalent modification cycle affected the steady-state output of the system, the sensitivity of the response to the stimulus, and the concentration of the stimulus required to provide the half-maximal response (S(50)). When both the modified and unmodified forms of the substrate protein were sequestered by the downstream target, the sensitivity of the response was dramatically decreased, but the S(50) was only modestly affected. Conversely, when the downstream target only sequestered the unmodified form of the substrate protein, significant effects were observed on both system sensitivity and S(50). Behaviors of the experimental systems were well approximated both by simple models allowing analytical solutions and by a detailed model based on the known interactions and enzymatic activities. Modeling and experimentation indicated that retroactivity may result in subsensitive responses, even if the covalent modification cycle displays significant ultrasensitivity in the absence of retroactivity. Thus, we provide examples of how a downstream target can alter the signaling properties of an upstream signal transduction covalent modification cycle.

Screening and Analysis of the Multiple Absorbed Bioactive Components and Metabolites in Rat Plasma After Oral Administration of Jitai Tablets by High-performance Liquid Chromatography/diode-array Detection Coupled with Electrospray Ionization Tandem Mass Spectrometry

Rapid Communications in Mass Spectrometry : RCM. Jun, 2010  |  Pubmed ID: 20486261

Based on the serum pharmacochemistry technique and high-performance liquid chromatography/diode-array detection (HPLC/DAD) coupled with electrospray tandem mass spectrometry (HPLC/ESI-MS/MS), a method for screening and analysis of the multiple absorbed bioactive components and metabolites of Jitai tablets (JTT) in orally dosed rat plasma was developed. Plasma was treated by methanol precipitation prior to liquid chromatography, and the separation was carried out on a Symmetry C(18) column, with a linear gradient (0.1% formic acid/water/acetonitrile). Mass spectra were acquired in negative and positive ion modes, respectively. As a result, 26 bioactive components originated from JTT and 5 metabolites were tentatively identified in orally dosed rat plasma by comparing their retention times and MS spectra with those of authentic standards and literature data. It is concluded that an effective and reliable analytical method was set up for screening the bioactive components of Chinese herbal medicine, which provided a meaningful basis for further pharmacology and active mechanism research of JTT.

[Construction of Recombinant Adenovirus Vector PAdxsi-green Fluorescent Protein-homo Sapiens NEL-like 1 and Transfected into Rat Bone Marrow Mesenchymal Stem Cells]

Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi = Zhongguo Xiufu Chongjian Waike Zazhi = Chinese Journal of Reparative and Reconstructive Surgery. May, 2010  |  Pubmed ID: 20540270

To construct a recombinant adenovirus vector pAdxsi-GFP-NELL1 that co-expressing green fluorescent protein (GFP) and homo sapiens NEL-like 1 (NELL1) protein (a protein strongly expressed in neural tissue encoding epidermal growth factor like domain), to observe its expression by transfecting the recombinant adenovirus into rat bone marrow mesenchymal stem cells (BMSCs) so as to lay a foundation for further study on osteogenesis of NELL1 protein.

Self-cleaning Diffractive Macroporous Films by Doctor Blade Coating

Langmuir : the ACS Journal of Surfaces and Colloids. Aug, 2010  |  Pubmed ID: 20617800

Here we report a scalable bottom-up technology for creating three-dimensionally highly ordered macroporous polymer films with excellent water-repelling and optical diffractive properties. A simple doctor blade coating process is first utilized to create silica colloidal crystal-polymer nanocomposites. The close-packed silica spheres are selectively removed to fabricate flexible macroporous polymer films with crystalline arrays of voids which are interconnected through small nanopores. The size of the voids can be easily controlled by tuning the duration of an oxygen reactive-ion etching process prior to the removal of the templating silica spheres. After surface functionalization with fluorosilane, superhydrophobic surface with large apparent water contact angle and small sliding angle can be obtained. The water-repelling property can be quantitatively explained by adapting the Cassie's dewetting model. We further demonstrate that self-cleaning functionality can be achieved on superhydrophobic macroporous coatings by preventing bacterial contamination. The high crystalline quality of the macroporous polymers also enables strong optical diffraction from the periodic lattice. The optical properties are evaluated by normal-incidence reflectance measurements and theoretical calculation using a scalar-wave approximation model. A good agreement between theory and experiment has been obtained. The simultaneous achievement of controlled dewetting and strong optical diffraction by templated porous films could open new applications in self-cleaning diffractive optics.

[Histomorphology Observation of Canine Whole Facial Nerve Treated with Chemically Extracted Acellular Methods]

Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi = Zhongguo Xiufu Chongjian Waike Zazhi = Chinese Journal of Reparative and Reconstructive Surgery. Jun, 2010  |  Pubmed ID: 20632512

Using chemically extracted acellular methods to treat extracranial section of the canine whole facial nerve, to evaluated its effects on nerve structure and the removal extent of Schwann cells and myelin.

Nanopyramid Surface Plasmon Resonance Sensors

Applied Physics Letters. Jun, 2010  |  Pubmed ID: 20661318

We report the achievement of sensitive chemical and biological sensing using periodic gold nanopyramids with nanoscale sharp tips created by a simple and scalable colloidal templating approach. The sharp tips and the long-range periodic structure of the nanopyramid arrays enable the excitement of both localized and propagating surface plasmons. The optical reflection and the detection sensitivity of the templated nanopyramid surface plasmon resonance sensors agree reasonably well with the theoretical predictions using a finite-difference time-domain model. We have also demonstrated that specific antigen-antibody binding can be detected by using nanopyramid arrays in a real-time and label-free manner.

Synthesis, Characterization, Cytotoxic Activities, and DNA-binding Studies of Ternary Copper(II) Complexes with New Coumarin Derivatives

Chemical & Pharmaceutical Bulletin. Aug, 2010  |  Pubmed ID: 20686250

In this study, two novel complexes [Cu(MCVH)phen(H(2)O)].ClO(4) (1) and [Cu(MCLH)phen(H(2)O)].ClO(4) (2) (here, MCVH(2)=(7-hydroxy-4-methyl-8-coumarinyl) valine, MCLH(2)=(7-hydroxy-4-methyl-8-coumarinyl) leucine) have been synthesized and characterized by elemental analyses, molar conductance, infrared spectra (IR), (1)H-NMR and UV-Vis measurements. The interactions of them with calf thymus DNA (ct DNA) have been investigated by absorption spectroscopy, fluorescence spectroscopy, circular dichroism spectroscopy and viscosity measurements. Experimental results reveal an intercalative interaction with DNA for the complexes, furthermore the binding affinity of 2 is higher than that of 1 according to the calculated binding constant values. In addition, they were evaluated for their cytotoxic activities toward human prostate cancer cell (PC3), human liver cell (L02) and human myeloid leukemia cancer cell (HL-60) by acid phosphoatase assay. Both of them showed significant cytotoxic potency.

Synthesis, Crystal Structure, Antioxidant Activity, and DNA-binding Studies of a Novel Ni(II) [2x2] Grid Complex with a Rigid Bistridentate Schiff Base Ligand

Chemical & Pharmaceutical Bulletin. Aug, 2010  |  Pubmed ID: 20686262

With a bistridentate Schiff-base ligand, N',N'(3)-bis[(1E)-1-(2-pyridinyl)ethylidene)] isophthalohydrazide (H(2)L), a [2x2]G grid complex, [Ni(4)(HL)(4)](ClO(4))(4).4H(2)O.0.5 CH(3)OH (1) has been synthesized and characterized spectroscopically and crystallographically. Spectrometric titrations, ethidium bromide displacement experiments, circular dichroism spectral analysis and viscosity measurements indicate that the compound 1 strongly binds with calf-thymus DNA, presumably via intercalation mechanism. Furthermore, the antioxidant activity (superoxide and hydroxyl radical) of the ligand and its nickel(II) complex is determined by using spectrophotometer methods in vitro. Complex 1 is found to possess potent antioxidant activity and be better than standard antioxidants like mannitol.

[Bone Histocompatibility of Surface Modified Nitinol Memory Alloy by Coating Titanium-niobium Alloy]

Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi = Zhongguo Xiufu Chongjian Waike Zazhi = Chinese Journal of Reparative and Reconstructive Surgery. Jul, 2010  |  Pubmed ID: 20695374

Surface modification of nitinol (NiTi) shape memory alloy is an available method to prevent nickel ion release and coating with titanium-niobium (TiNb) alloy will not affect the superelasticity and shape memory of NiTi. To evaluate the bone histocompatibility of NiTi shape memory alloy implants coated by TiNb in vivo.

Large-scale Colloidal Self-assembly by Doctor Blade Coating

Langmuir : the ACS Journal of Surfaces and Colloids. Aug, 2010  |  Pubmed ID: 20695556

This article reports a simple, roll-to-roll compatible coating technology for producing 3D highly ordered colloidal crystal-polymer nanocomposites, colloidal crystals, and macroporous polymer membranes. A vertically beveled doctor blade is utilized to shear align silica microsphere-monomer suspensions to form large-area nanocomposites in a single step. The polymer matrix and the silica microspheres can be selectively removed to create colloidal crystals and self-standing macroporous polymer membranes. The thickness of the shear-aligned crystal is correlated with the viscosity of the colloidal suspension, and the coating speed and the correlations can be qualitatively explained by adapting the mechanisms developed for conventional doctor blade coating. We further demonstrate that the doctor blade coating speed can be significantly increased by using a dual-blade setup. The optical properties of the self-assembled structures are evaluated by normal-incidence reflection measurements, and the experimental results agree well with the theoretical predictions using Bragg's law and a scalar wave approximation model. We have also demonstrated that the templated macroporous polymers with interconnected voids and uniform interconnecting nanopores can be directly used as filtration membranes to achieve size-exclusive separation of particles.

An ESRP-regulated Splicing Programme is Abrogated During the Epithelial-mesenchymal Transition

The EMBO Journal. Oct, 2010  |  Pubmed ID: 20711167

Alternative splicing achieves coordinated changes in post-transcriptional gene expression programmes through the activities of diverse RNA-binding proteins. Epithelial splicing regulatory proteins 1 and 2 (ESRP1 and ESRP2) are cell-type-specific regulators of transcripts that switch splicing during the epithelial-mesenchymal transition (EMT). To define a comprehensive programme of alternative splicing that is regulated during the EMT, we identified an extensive ESRP-regulated splicing network of hundreds of alternative splicing events within numerous genes with functions in cell-cell adhesion, polarity, and migration. Loss of this global ESRP-regulated epithelial splicing programme induces the phenotypic changes in cell morphology that are observed during the EMT. Components of this splicing signature provide novel molecular markers that can be used to characterize the EMT. Bioinformatics and experimental approaches revealed a high-affinity ESRP-binding motif and a predictive RNA map that governs their activity. This work establishes the ESRPs as coordinators of a complex alternative splicing network that adds an important post-transcriptional layer to the changes in gene expression that underlie epithelial-mesenchymal transitions during development and disease.

Direct Fluorescence in Situ Hybridization (FISH) in Escherichia Coli with a Target-specific Quantum Dot-based Molecular Beacon

Biosensors & Bioelectronics. Oct, 2010  |  Pubmed ID: 20729070

Quantum dots (QDs) are inorganic fluorescent nanocrystals with excellent properties such as tunable emission spectra and photo-bleaching resistance compared with organic dyes, which make them appropriate for applications in molecular beacons. In this work, quantum dot-based molecular beacons (QD-based MBs) were fabricated to specifically detect β-lactamase genes located in pUC18 which were responsible for antibiotic resistance in bacteria Escherichia coli (E. coli) DH5α. QD-based MBs were constructed by conjugating mercaptoacetic acid-quantum dots (MAA-QDs) with black hole quencher 2 (BHQ2) labeled thiol DNA vial metal-thiol bonds. Two types of molecular beacons, double-strands beacons and hairpin beacons, were observed in product characterization by gel electrophoresis. Using QD-based MBs, one-step FISH in tiny bacteria DH5α was realized for the first time. QD-based MBs retained their bioactivity when hybridizing with complementary target DNA, which showed excellent advantages of eliminating background noise caused by adsorption of non-specific bioprobes and achieving clearer focus of genes in plasmids pUC18, and capability of bacterial cell penetration and signal specificity in one-step in situ hybridization.

PMS-1077, a PAF Antagonist, Induced Differentiation of HL-60 Cells with Its Novel Activity

Cell Biology International. Dec, 2010  |  Pubmed ID: 20812915

The cell differentiation-inducing effect of 2-N,N-diethylaminocarbonyloxymethyl-1-diphenylmethyl-4-(3,4,5-trimethoxybenzoyl) piperazine, hydrochloride (PMS-1077) was determined in human leukaemic HL-60 cells with profiling of cell proliferation, analysis of cell cycling, characterization of expression of various CD molecules and determination of phagocytotic activity of differentiated HL-60 cells. After treatment with PMS-1077, HL-60 cells exhibited a decreased cell viability during which cell cycle was arrested in G₀-/G₁-phase. Flow cytometric analysis showed CD11b and CD14 were up-regulated, whereas CD15 was unaffected. Together with the finding that PMS-1077-treated HL-60 cells exhibited activities of differentiation by examining their ability of phagocytosing latex beads, an antiproliferative effect and a differentiation-inducing role were determined for PMS-1077 in HL-60 cells.

Scalable Fabrication of Superhydrophobic Hierarchical Colloidal Arrays

Journal of Colloid and Interface Science. Dec, 2010  |  Pubmed ID: 20850756

Here we report a scalable bottom-up technology for assembling hierarchical colloidal arrays with superhydrophobic surface. Non-close-packed (NCP) colloidal multilayers, which facilitate the formation of more hydrophobic surface than close-packed arrays due to a higher fraction of entrapped air in between colloidal particles, are first fabricated by a simple spin-coating technology. Uniform silica nanoparticles are then assembled on the NCP microsphere arrays by a second spin-coating process. After surface functionalization of silica particles with fluorosilane, the resulting hierarchical colloidal arrays exhibit superhydrophobic surface with high apparent water contact angle (159°) and low contact angle hysteresis (4.7°). The experimental results on both the wettability and contact angle hysteresis can be qualitatively explained by adapting the Cassie's model. This spin-coating-based colloidal self-assembly technology is compatible with standard microfabrication and enables large-scale production of superhydrophobic coatings that could find important technological applications ranging from self-cleaning diffractive optics to microfluidic devices.

Pin1 Expression Contributes to Lung Cancer: Prognosis and Carcinogenesis

Cancer Biology & Therapy. Jan, 2010  |  Pubmed ID: 20009523

Lung cancer remains the most common cause of death for malignancy in both men and women. Current therapies for NSCLC patients are inefficient due to the lack of diagnostic and therapeutic markers. The phospho-Ser/Thr-Pro specific prolyl-isomerase Pin1 is overexpressed in many different cancers, including NSCLC, and may possibly be used as a target for cancer therapy. We identified 79 cases with the follow-up survival and investigated the clinical relevance of Pin1 expression in NSCLC patients. To validate the oncogenic potential of Pin1 in lung cells, we overexpressed Pin1 in Glc82 cells, and downregulated Pin1 by RNA interference in H1299 cells. The 5-year survival rate of the 79 patients was 54.6%. High expression of Pin1 correlated with poor survival by univariate analysis as well as by multivariate analysis, demonstrating that high expression of Pin1 was an independent prognostic factor. Consistent with the clinical findings, overexpression of Pin1 in Glc82 cells increased cell growth and colony formation and tumorigenicity in nude mice including cell migration, invasion. To further validate the role of Pin1 in lung cancer carcinogenesis, lentivirus-mediated siRNA targeting of Pin1 resulted in the stable suppression of both cell growth, anchorage-independent growth in soft agar and tumorigenic including cell migration, invasion in H1299 cells. Pin1 expression may be an unfavorable prognostic factor in patients of NSCLC patients, and these results indicate that Pin1 may have a role in tumor development and metastasis and thus could serve as a novel target for treatment of NSCLC.

Molecular Networks for the Study of TCM Pharmacology

Briefings in Bioinformatics. Jul, 2010  |  Pubmed ID: 20038567

To target complex, multi-factorial diseases more effectively, there has been an emerging trend of multi-target drug development based on network biology, as well as an increasing interest in traditional Chinese medicine (TCM) that applies a more holistic treatment to diseases. Thousands of years' clinic practices in TCM have accumulated a considerable number of formulae that exhibit reliable in vivo efficacy and safety. However, the molecular mechanisms responsible for their therapeutic effectiveness are still unclear. The development of network-based systems biology has provided considerable support for the understanding of the holistic, complementary and synergic essence of TCM in the context of molecular networks. This review introduces available sources and methods that could be utilized for the network-based study of TCM pharmacology, proposes a workflow for network-based TCM pharmacology study, and presents two case studies on applying these sources and methods to understand the mode of action of TCM recipes.

Bioinspired Assembly of Surface-roughened Nanoplatelets

Journal of Colloid and Interface Science. Apr, 2010  |  Pubmed ID: 20102769

Here we report a novel electrophoretic deposition technology for assembling surface-roughened inorganic nanoplatelets into ordered multilayers that mimic the brick-and-mortar nanostructure found in the nacreous layer of mollusk shells. A thin layer of sol-gel silica is coated on smooth gibbsite nanoplatelets in order to increase the surface roughness to mimic the asperity of aragonite platelets found in nacres. To avoid the severe cracking caused by the shrinkage of sol-gel silica during drying, polyelectrolyte polyethyleneimine is used to reverse the surface charge of silica-coated-gibbsite nanoplatelets and increase the adherence and strength of the electrodeposited films. Polymer nanocomposites can then be made by infiltrating the interstitials of the aligned nanoplatelet multilayers with photocurable monomer followed by photopolymerization. The resulting self-standing films are highly transparent and exhibit nearly three times higher tensile strength and one-order-of-magnitude higher toughness than those of pure polymer. The measured tensile strength agrees with that predicted by a simple shear lag model.

Templated Fabrication of Metal Half-shells for Surface-enhanced Raman Scattering

Physical Chemistry Chemical Physics : PCCP. Feb, 2010  |  Pubmed ID: 20119616

Here we report a scalable colloidal templating approach for producing metal half-shells as efficient surface-enhanced Raman scattering (SERS) substrates. Nonclose-packed monolayer colloidal crystals created by a spin-coating technology are used as structural template to fabricate both water-dispersed half-shells and disordered arrays of half-shells with preferential upright orientation. The sharp edges of the half-shells and the small gaps between adjacent shells can significantly enhance the local electromagnetic field, resulting in high SERS enhancement factor (up to 10(10)) which is nearly 2 orders of magnitude higher than those of periodic substrates produced by other colloidal templating approaches. We have also demonstrated that the thickness of the half-shells determines the surface plasmon resonance and the resulting SERS enhancement. Counterintuitively, the disordered arrays of oriented half-shells show reproducible enhancement with a standard deviation of less than 20%. This new bottom-up approach enables the large-scale production of SERS substrates that are at least 2 orders of magnitude larger in area than those made by other colloidal lithography technologies. The resulting substrates with high and reproducible SERS enhancement are promising for ultrasensitive chemical and biological sensing.

Room-temperature Reaction of Oxygen with Gold: an in Situ Ambient-pressure X-ray Photoelectron Spectroscopy Investigation

Journal of the American Chemical Society. Mar, 2010  |  Pubmed ID: 20146473

The interaction of O(2) with gold foil and gold nanoparticles grown by thermal deposition on TiO(2)(110) was studied by in situ ambient pressure X-ray photoelectron spectroscopy at room temperature. No spontaneous dissociation of O(2) was observed either on Au foil or on Au nanoparticles up to 1 Torr of O(2). X-ray irradiation, however, is very effective in promoting gold oxidation on both surfaces in the presence of O(2). Our results help reconcile recent conflicting experimental observations regarding the activation of molecular oxygen, which is a crucial issue in Au catalyzed oxidation reactions.

A Data Compression Algorithm for Wireless Sensor Networks Based on an Optimal Order Estimation Model and Distributed Coding

Sensors (Basel, Switzerland). 2010  |  Pubmed ID: 22163395

In many wireless sensor network applications, the possibility of exceptions occurring is relatively small, so in a normal situation, data obtained at sequential time points by the same node are time correlated, while, spatial correlation may exist in data obtained at the same time by adjacent nodes. A great deal of node energy will be wasted if data which include time and space correlation is transmitted. Therefore, this paper proposes a data compression algorithm for wireless sensor networks based on optimal order estimation and distributed coding. Sinks can obtain correlation parameters based on optimal order estimation by exploring time and space redundancy included in data which is obtained by sensors. Then the sink restores all data based on time and space correlation parameters and only a little necessary data needs to be transmitted by nodes. Because of the decrease of redundancy, the average energy cost per node will be reduced and the life of the wireless sensor network will obviously be extended as a result.

A Sensor Network Data Compression Algorithm Based on Suboptimal Clustering and Virtual Landmark Routing Within Clusters

Sensors (Basel, Switzerland). 2010  |  Pubmed ID: 22163396

A kind of data compression algorithm for sensor networks based on suboptimal clustering and virtual landmark routing within clusters is proposed in this paper. Firstly, temporal redundancy existing in data obtained by the same node in sequential instants can be eliminated. Then sensor networks nodes will be clustered. Virtual node landmarks in clusters can be established based on cluster heads. Routing in clusters can be realized by combining a greedy algorithm and a flooding algorithm. Thirdly, a global structure tree based on cluster heads will be established. During the course of data transmissions from nodes to cluster heads and from cluster heads to sink, the spatial redundancy existing in the data will be eliminated. Only part of the raw data needs to be transmitted from nodes to sink, and all raw data can be recovered in the sink based on a compression code and part of the raw data. Consequently, node energy can be saved, largely because transmission of redundant data can be avoided. As a result the overall performance of the sensor network can obviously be improved.

SPICi: a Fast Clustering Algorithm for Large Biological Networks

Bioinformatics (Oxford, England). Apr, 2010  |  Pubmed ID: 20185405

Clustering algorithms play an important role in the analysis of biological networks, and can be used to uncover functional modules and obtain hints about cellular organization. While most available clustering algorithms work well on biological networks of moderate size, such as the yeast protein physical interaction network, they either fail or are too slow in practice for larger networks, such as functional networks for higher eukaryotes. Since an increasing number of larger biological networks are being determined, the limitations of current clustering approaches curtail the types of biological network analyses that can be performed.

Clinical Characteristics and Surgical Treatment of Oesophageal Gastrointestinal Stromal Tumours

European Journal of Cardio-thoracic Surgery : Official Journal of the European Association for Cardio-thoracic Surgery. Aug, 2010  |  Pubmed ID: 20206541

Oesophageal gastrointestinal stromal tumours (GISTs) are extremely rare. The preoperative diagnosis is complicated by lack of specificity and the clinical features of patients with oesophageal GISTs need to be fully studied.

[Mechanisms of Autologous Chondrocytes Mass Transplantation in the Repair of Cartilage Defects of Rabbits' Knee]

Zhongguo Gu Shang = China Journal of Orthopaedics and Traumatology. Sep, 2010  |  Pubmed ID: 20964000

To trace the pathological changes of the cultured autologous chondrocytes mass after implanted in cartilage defects and investigate the pathophysiological mechanisms of the antologous chondrocytes mass transplantation in the repair of cartilage defects.

Multilayered Nanofibers from Stacks of Single-molecular Thick Nanosheets of Hexakis(alkoxy)triphenylenes

Chemical Communications (Cambridge, England). Dec, 2010  |  Pubmed ID: 20972497

Symmetrically substituted hexakis(alkoxy)triphenylene (HAT) derivatives were assembled into single molecular thick 2D nanosheets, which stacked further to give multilayered nanofibers through a convenient solution process. Detailed information on molecular arrangement was unraveled by various imaging techniques and diffraction studies.

A Scanning Tunneling Microscope Study on an Ordered Mixed Monolayer of Bis(4,5-dihydronaphtho[1,2-d])-tetrathiafulvalene and N-tetradecane on Highly Oriented Pyrolytic Graphite

Journal of Nanoscience and Nanotechnology. Nov, 2010  |  Pubmed ID: 21137923

Tetrathiafulvalene (TTF) and its derivatives (TTFs) have been successfully used as building blocks to form charge transfer salts and organic semiconductors because of their special structures and rich electron nature. We report the formation of ordered mixed binary-component monolayer consisting of Bis(4,5-dihydronaphtho[1,2-d])tetrathiafulvalene (DH-TTF) and n-tetradecane (n-C14H30) molecules on highly oriented pyrolytic graphite (HOPG) surface. Scanning tunneling microscope (STM) imaging reveals that the two different kinds of molecules can spontaneously form ordered periodic phase separation structures on the substrate, in which ordered DH-TTF double- (or single-) lamella structures are periodically tuned by ordered n-C14H30 double- (or single-) lamella structures. Furthermore, scanning tunneling spectrum (STS) measurements by addressing the individual DH-TTF and n-C14H30 molecules in the ordered monolayer show that the two different kinds of molecules exhibit completely different I(V) characters on the HOPG substrate. The modulated arrangement of the TTF derivative by insulating molecules opens a possible route to construct organic conducting molecule ribbons for potential application in nanodevices.

Effect of Ablation of Complex Fractionated Atrial Electrogram on Vagal Modulation in Dogs

Chinese Medical Journal. Nov, 2010  |  Pubmed ID: 21163132

Clinical observations have shown that the complex fractionated atrial electrogram (CFAE) associates with ganglionated plexus activity in the cardiac autonomic nervous system. This study aimed to investigate the impact of CFAE ablation on vagal modulation to atria and vulnerability to develop atrial fibrillation (AF).

[Statistical Study on Correlation Between Cerebral Arteriovenous Malformation and Hemodynamic Aneurysms]

Zhonghua Wai Ke Za Zhi [Chinese Journal of Surgery]. Nov, 2010  |  Pubmed ID: 21211454

to explore the characteristic factors of arteriovenous malformation (AVM) which have statistically significant correlation with hemodynamic aneurysms.

[Experimental Study of Protective Effects of Hepatotrophic Factors on Hepatic Functions in Rats with Portal Hypertension After Portacaval Shunt]

Zhonghua Yi Xue Za Zhi. Dec, 2010  |  Pubmed ID: 21223822

To investigate the protective effects of hepatotrophic factors (hepatocyte growth-promoting factor and insulin) on hepatic functions and pathology in rats with portal hypertension after portacaval shunt.

Structural and Degradation Characteristics of an Innovative Porous PLGA/TCP Scaffold Incorporated with Bioactive Molecular Icaritin

Biomedical Materials (Bristol, England). Oct, 2010  |  Pubmed ID: 20876954

Phytomolecules may chemically bind to scaffold materials for medical applications. The present study used an osteoconductive porous poly(l-lactide-co-glycolide)/tricalcium phosphate (PLGA/TCP) to incorporate an exogenous phytoestrogenic molecule icaritin to form a PLGA/TCP/icaritin composite scaffold material with potential slow release of icaritin during scaffold degradation. Accordingly, the present study was designed to investigate its in vitro degradation characteristics and the release pattern of icaritin at three different doses (74 mg, 7.4 mg and 0.74 mg per 100 g PLGA/TCP, i.e. in the PLGA/TCP/icaritin-H, -M and -L groups, respectively). A PLGA/TCP/icaritin porous composite scaffold was fabricated using a computer-controlled printing machine. The PLGA/TCP/icaritin scaffolds were incubated in saline at 37 °C for 12 weeks and the pure PLGA/TCP scaffold served as a control. During the 12 weeks in vitro degradation, the scaffolds in all four groups showed changes, including a decrease in weight, volume and pore size of the composite scaffold, while there was a decrease in acidity and an increase in Ca and lactic acid concentrations in the degradation medium, especially after 7 weeks. The rate of degradation was explained by the relationship with the content of icaritin incorporated into the scaffolds. The higher the icaritin content in the scaffolds, the slower the degradation could be observed during 12 weeks. After 12 weeks, the SEM showed that the surface of the PLGA/TCP and PLGA/TCP/icaritin-L groups was relatively smooth with a gradual decrease in number and size of the micropores, while the porous morphology on the surface of the PLGA/TCP/icaritin-M and PLGA/TCP/icaritin-H groups was partly maintained, accompanied by a decrease in phosphate (P) and calcium (Ca) contents at the surface. Though the mechanical property of the PLGA/TCP/icaritin scaffold decreased after degradation, its porous structure was maintained, which was essential for cell migration and ingrowth of newly regenerated tissues in vivo. The controlled release of icaritin from the composite scaffold reached about 70% of the incorporated icaritin into the degradation medium after 12 weeks. The above findings suggested that the structural and degradation properties of the porous composite PLGA/TCP/icaritin scaffold were dependent on icaritin concentrations. This innovative composite porous scaffold material developed in the present study may be used as a good scaffold material for enhancing bone repair, especially at high concentrations of icaritin. In vivo confirmation is, however, needed to substantiate our in vitro findings.

[Extraction Techniques and Biocompatibility Evaluations of Naturally Derived Nerve Extracellular Matrix]

Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi = Zhongguo Xiufu Chongjian Waike Zazhi = Chinese Journal of Reparative and Reconstructive Surgery. Sep, 2010  |  Pubmed ID: 20939489

Native extracellular matrix (ECM) is comprised of a complex network of structural and regulatory proteins that are arrayed into a tissue-specific, biomechanically optimal, fibrous matrix. The multifunctional nature of the native ECM will need to be considered in the design and fabrication of tissue engineering scaffolds. To investigate the extraction techniques of naturally derived nerve ECM and the feasibility of nerve tissue engineering scaffold.

NELL1 Promotes High-quality Bone Regeneration in Rat Femoral Distraction Osteogenesis Model

Bone. Mar, 2011  |  Pubmed ID: 20959151

NELL1 (NEL-like molecule-1; NEL [a protein strongly expressed in neural tissue encoding epidermal growth factor like domain]) is a cranisynostosis-associated molecule directly regulated by Runx2, the master molecule in controlling osteoblastic differentiation. NELL1 has exhibited potent osteoinductive activity for bone regeneration in several animal models. However, its capacity for promoting repair of long-bone defects remains unknown. In this study, we investigated the osteogenic effects of NELL1 on femoral distraction osteogenesis using adenoviral gene delivery and multiple approaches of in vivo analysis. Thirty Sprague-Dawley (SD) rats were randomly assigned to 3 groups for treatment (n=10 each): adenovirus-green fluorescent protein (Ad-GFP)-NELL1 or Ad-GFP at 1×10⁹ plaque-forming units/ml diluted in saline, or saline alone. The femoral distraction was at a speed of 0.25 mm every 12h for 14 days, and a single injection of Ad-GFP-NELL1 or Ad-GFP was given at the mid-distraction period. The effective NELL1 delivery in vivo after Ad-GFP-NELL1 injection was evaluated by optical imaging. The bone regeneration was assessed quantitatively at days 21, 28, 42, and 56 by live 3-D micro-computed tomography (micro-CT), and animals were sacrificed at day 56 for biomechanical testing and histological analysis. Exogenous NELL1 was expressed in the distracted gap for at least 14 days after Ad-GFP-NELL1 transfection. The bone union rate in the distracted gap was significantly higher with Ad-GFP-NELL1 than with Ad-GFP (9/9 vs. 4/9 rats) or saline alone (5/9 rats) at day 56. The serial 3-D micro-CT images and quantitation obtained with the development and application of radiolucent external fixators showed less callus but more mature cortical bones formed with Ad-GFP-NELL1 than with Ad-GFP transfection and saline administration during distraction osteogenesis. The biomechanical properties of femur samples with Ad-GFP-NELL1 transfection were better than samples with Ad-GFP transfection or saline treatment, and were similar with unoperated femurs. Histology revealed cartilaginous tissues in the middle of distraction gaps with Ad-GFP transfection and saline treatment but only bony bridges with Ad-GFP-NELL1 transfection at the final time point (day 56). Coincidently, the expression of Runx2, BMP2, and BMP7 did not differ among groups at day 56, whereas the expression of osteocalcin and osteopontin was slightly higher with Ad-GFP-NELL1 transfection. Thus, sustained Ad-NELL1 protein delivery into a local area of a rat femoral distraction osteogenesis model remarkably improved regeneration of good-quality bones and accelerated bone union at a high rate. Acquiring serial micro-CT data during rat femoral distraction osteogenesis and regional adenovirus delivery of NELL1 may facilitate future in vivo studies.

Load-induced Modulation of Signal Transduction Networks

Science Signaling. 2011  |  Pubmed ID: 21990429

Biological signal transduction networks are commonly viewed as circuits that pass along information--in the process amplifying signals, enhancing sensitivity, or performing other signal-processing tasks--to transcriptional and other components. Here, we report on a "reverse-causality" phenomenon, which we call load-induced modulation. Through a combination of analytical and experimental tools, we discovered that signaling was modulated, in a surprising way, by downstream targets that receive the signal and, in doing so, apply what in physics is called a load. Specifically, we found that non-intuitive changes in response dynamics occurred for a covalent modification cycle when load was present. Loading altered the response time of a system, depending on whether the activity of one of the enzymes was maximal and the other was operating at its minimal rate or whether both enzymes were operating at submaximal rates. These two conditions, which we call "limit regime" and "intermediate regime," were associated with increased or decreased response times, respectively. The bandwidth, the range of frequency in which the system can process information, decreased in the presence of load, suggesting that downstream targets participate in establishing a balance between noise-filtering capabilities and a circuit's ability to process high-frequency stimulation. Nodes in a signaling network are not independent relay devices, but rather are modulated by their downstream targets.

Context-dependent Robustness to 5' Splice Site Polymorphisms in Human Populations

Human Molecular Genetics. Mar, 2011  |  Pubmed ID: 21224255

There has been growing evidence for extensive diversity of alternative splicing in human populations. Genetic variants within the 5' splice site can cause splicing differences among human individuals and constitute an important class of human disease mutations. In this study, we explored whether natural variations of splicing could reveal important signals of 5' splice site recognition. In seven lymphoblastoid cell lines of Asian, European and African ancestry, we identified 1174 single nucleotide polymorphisms (SNPs) within the consensus 5' splice site. We selected 129 SNPs predicted to significantly alter the splice site activity, and quantitatively examined their splicing impact in the seven individuals. Surprisingly, outside of the essential GT dinucleotide position, only ∼14% of the tested SNPs altered splicing. Bioinformatic and minigene analyses identified signals that could modify the impact of 5' splice site polymorphisms, most notably a strong 3' splice site and the presence of intronic motifs downstream of the 5' splice site. Strikingly, we found that the poly-G run, a known intronic splicing enhancer, was the most significantly enriched motif downstream of exons unaffected by 5' splice site SNPs. In TRIM62, the upstream 3' splice site and downstream intronic poly-G runs functioned redundantly to protect an exon from its 5' splice site polymorphism. Collectively, our study reveals widespread context-dependent robustness to 5' splice site polymorphisms in human transcriptomes. Consequently, certain exons are more susceptible to 5' splice site mutations. Additionally, our work demonstrates that genetic diversity of alternative splicing can provide significant insights into the splicing code of mammalian cells.

A New Animal Model of Osteonecrosis Induced by Focal Alternative Cooling and Heating Insults

Zhongguo Yi Xue Ke Xue Yuan Xue Bao. Acta Academiae Medicinae Sinicae. Aug, 2011  |  Pubmed ID: 21906444

Objective To establish a new animal model of osteonecrosis of the femoral head(ONFH) with improved consistency and incidence of femoral head collapse for studies on the mechanism of osteonecrosis.

Biomarkers in the Early Period of Acute Myocardial Infarction in Rat Serum and Protective Effects of Shexiang Baoxin Pill Using a Metabolomic Method

Journal of Ethnopharmacology. Nov, 2011  |  Pubmed ID: 22001859

To identify the biomarkers in early period of acute myocardial infarction (AMI) in rat serum and reveal the effective mechanism of a Traditional Chinese Medicine (TCM) named Shexiang Baoxin Pill (SBP).

[Effect of Different Number of Bone Marrow Mesenchymal Stem Cells on Growth of Rat Dorsal Root Ganglia in Vitro]

Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi = Zhongguo Xiufu Chongjian Waike Zazhi = Chinese Journal of Reparative and Reconstructive Surgery. Oct, 2011  |  Pubmed ID: 22069984

Bone marrow mesenchymal stem cells (BMSCs), as replacement cells of Schwann cells, can increase the effect of peripheral nerve repair. However, it has not yet reached any agreement to add the appropriate number of seeded cells in nerve scaffold. To investigate the effect of different number of BMSCs on the growth of rat dorsal root ganglia (DRG).

A Source of Ultrasensitivity in the Glutamine Response of the Bicyclic Cascade System Controlling Glutamine Synthetase Adenylylation State and Activity in Escherichia Coli

Biochemistry. Dec, 2011  |  Pubmed ID: 22085244

Glutamine synthetase (GS) activity in Escherichia coli is regulated by reversible adenylylation, brought about by a bicyclic system comprised of uridylyltransferase/uridylyl-removing enzyme (UTase/UR), its substrate, PII, adenylyltransferase (ATase), and its substrate, GS. The modified and unmodified forms of PII produced by the upstream UTase/UR-PII cycle regulate the downstream ATase-GS cycle. A reconstituted UTase/UR-PII-ATase-GS bicyclic system has been shown to produce a highly ultrasensitive response of GS adenylylation state to the glutamine concentration, but its composite UTase/UR-PII and ATase-GS cycles displayed moderate glutamine sensitivities when examined separately. Glutamine sensitivity of the bicyclic system was significantly reduced when the trimeric PII protein was replaced by a heterotrimeric form of PII that was functionally monomeric, and coupling between the two cycles was different in systems containing wild-type or heterotrimeric PII. Thus, the trimeric nature of PII played a role in the glutamine response of the bicyclic system. We therefore examined regulation of the individual AT (adenylylation) and AR (deadenylylation) activities of ATase by PII preparations with various levels of uridylylation. AR activity was affected in a linear fashion by PII uridylylation, but partially modified wild-type PII activated the AT much less than expected based on the extent of PII modification. Partially modified wild-type PII also bound to ATase less than expected based upon the fraction of modified subunits. Our results suggest that the AT activity is only bound and activated by completely unmodified PII and that this design is largely responsible for ultrasensitivity of the bicyclic system.

Genetic Variation of Pre-mRNA Alternative Splicing in Human Populations

Wiley Interdisciplinary Reviews. RNA. Nov, 2011  |  Pubmed ID: 22095823

The precise splicing outcome of a transcribed gene is controlled by complex interactions between cis regulatory splicing signals and trans-acting regulators. In higher eukaryotes, alternative splicing is a prevalent mechanism for generating transcriptome and proteome diversity. Alternative splicing can modulate gene function, affect organismal phenotype and cause disease. Common genetic variation that affects splicing regulation can lead to differences in alternative splicing between human individuals and consequently impact expression level or protein function. In several well-documented examples, such natural variation of alternative splicing has indeed been shown to influence disease susceptibility and drug response. With new microarray and sequencing-based genomic technologies that can analyze eukaryotic transcriptomes at the exon or nucleotide level, it has become possible to globally compare the alternative splicing profiles across human individuals in any tissue or cell type of interest. Recent large-scale transcriptome studies using high-density splicing-sensitive microarray and deep RNA sequencing (RNA-Seq) have revealed widespread genetic variation of alternative splicing in humans. In the future, an extensive catalog of alternative splicing variation in human populations will help elucidate the molecular underpinnings of complex traits and human diseases, and shed light on the mechanisms of splicing regulation in human cells. WIREs RNA 2011. doi: 10.1002/wrna.120 For further resources related to this article, please visit the WIREs website.

Serodiagnosis of Experimental Sparganum Infections of Mice and Human Sparganosis by ELISA Using ES Antigens of Spirometra Mansoni Spargana

Parasitology Research. Jun, 2011  |  Pubmed ID: 21181193

We conducted a study of serodiagnosis of experimental sparganum infections of mice and human sparganosis by enzyme-linked immunosorbent assay (ELISA) using excretory-secretory (ES) antigens of Spirometra mansoni spargana and compared the sensitivity and specificity of crude and ES antigens for detecting the specific anti-sparganum IgG antibodies. By crude antigen ELISA and ES antigen ELISA, anti-sparganum IgG was detected in all of 30 serum samples of the infected mice; no cross-reactions were observed in serum samples of the mice infected with Trichinella spiralis, Schistosoma japanicum, Toxoplasma gondii, and normal mice. Anti-sparganum IgG was detected by ES antigen ELISA in sera of mice infected with one, two, four, six, and eight spargana at 3 weeks post-infection (wpi), with a detection rate of 100%, and lasted to 18 wpi when the experiment was ended. The difference in anti-sparganum antibody levels among five groups of the infected mice was statistically significant (F=245.296, p<0.05); the antibody levels were correlated with infecting doses of spargana (r=0.323, p<0.05). The sensitivity of both ELISA in detecting the serum samples of patients with sparganosis was 100% (20/20), but 96.72% (59/61) of specificity of ES antigen ELISA in detecting serum samples of patients with cysticercosis, echinococcosis, paragonimiosis, clonorchiosis, and schistosomiasis, and healthy persons was significantly greater than 72.13% (44/61) of crude antigen ELISA (χ (2) = 14.027, p<0.05). Our finding indicates that ELISA using ES antigens of S. mansoni spargana may be applied to the specific early serodiagnosis of sparganosis.

Human Umbilical Cord Wharton's Jelly-derived Mesenchymal Stem Cells Differentiate into a Schwann-cell Phenotype and Promote Neurite Outgrowth in Vitro

Brain Research Bulletin. Feb, 2011  |  Pubmed ID: 21194558

Cell-based therapy has achieved promising functional recovery for peripheral nerve repair. Although Schwann cells (SCs) and bone marrow derived mesenchymal stromal cells (BM-MSCs) are the main cell source for nerve tissue engineering, the clinical application is limited because of donor site morbidity, the invasive procedure, and the decreased number of SCs and BM-MSCs. Wharton's jelly-derived mesenchymal stem cells (WJMSCs) could be a promising cell source for nerve tissue engineering because they are easily accessible and their use has no ethical issues. We investigated the phenotypic, molecular and functional characteristics of WJMSCs differentiated along a Schwann-cell lineage. Cultured WJMSCs were isolated from human umbilical cord, and the undifferentiated WJMSCs were confirmed by the detection of MSC-specific cell-surface markers. WJMSCs treated with a mixture of glial growth factors (basic fibroblast growth factor, platelet-derived growth factor and forskolin) adopted a spindle-like morphology similar to SCs. Immunocytochemical staining, RT-PCR analysis, and Western blot analysis revealed that the treated cells expressed the glial markers glial fibrillary acidic protein, p75, S100 and P0 and indicative of differentiation. On co-culture with dorsal root ganglia neurons, the differentiated WJMSCs enhanced the number of sprouting neurites and neurite length in dorsal root ganglia neurons. Furthermore, using enzyme-linked immunosorbent assay and RT-PCR methodology, we found differentiated WJMSCs secrete and express neurotrophic factors, including brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), and neurotrophin-3 (NT-3). Quantification of neurite outgrowth from PC12 cells grown in differentiated WJMSCs-conditioned media demonstrates that the neurite length is significantly more than control medium and undifferentiated WJMSCs group. WJMSCs can be differentiated into cells that are Schwann-like in terms of morphologic features, phenotype, and function and could be suitable Schwann-cell substitutes for nerve repair in clinical applications.

Behavioral and Genetic Dissection of a Mouse Model for Advanced Sleep Phase Syndrome

Sleep. Jan, 2011  |  Pubmed ID: 21203370

The adaptive value of the endogenous circadian clock arises from its ability to synchronize (i.e., entrain) to external light-dark (LD) cycles at an appropriate phase. Studies have suggested that advanced circadian phase alignment might result from shortening of the period length of the clock. Here we explore mechanisms that contribute to an early activity phase in CAST/EiJ (CAST) mice.

Micro-CT-based Bone Ceramic Scaffolding and Its Performance After Seeding with Mesenchymal Stem Cells for Repair of Load-bearing Bone Defect in Canine Femoral Head

Journal of Biomedical Materials Research. Part B, Applied Biomaterials. Feb, 2011  |  Pubmed ID: 21210512

Osteonecrosis of the femoral head is a debilitating and painful orthopedic condition characterized by joint collapse. Salvage of the femoral head is highly desirable to preserve the contour and mechanical properties and prevent joint collapse. This study aimed to develop a new tissue-engineering approach for treatment of large bone defect in femoral head, that is, after osteonecrosis. The biphasic calcium phosphate (BCP) ceramic scaffolds were fabricated by a 3D gel-lamination technique based on micro-computed tomography (micro-CT) images of the cancellous bone microarchitecture of femoral heads. After seeding with autologous bone marrow-derived mesenchymal stem cells (BMSCs) in vitro, the cell-scaffold composite was implanted into a bone defect surgically induced in canine femoral head via trapdoor procedure, which was a common procedure for treatment of osteonecrosis. A total of 24 adult dogs were randomly divided into three groups (n = 8 each) for implantation of the BCP scaffold with or without with BMSCs, and also the autologous bone chips for comparisons. All animals were sacrificed at 30 weeks postoperatively and processed for radiological and histological evaluations. The contour of the femoral head was well preserved with implantation of BCP scaffolds with or without BMSCs, whereas joint collapse was found after treatment with autologous bone chips. The osteointegration and new bone formation was significantly greater with BCP scaffold implantation with than without BMSC seeding and showed greater strength and compressive modulus in the repair site. Micro-CT-based bone ceramic scaffolds seeding with BMSC might be a promising way to repair bone defects in the femoral head.

Potential Biomarkers in the Urine of Myocardial Infarction Rats: a Metabolomic Method and Its Application

Molecular BioSystems. Mar, 2011  |  Pubmed ID: 21152560

A metabolomic method using reversed-phase liquid chromatography/quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS) was developed to obtain a systematic view of the development and progression of myocardial infarction (MI). By combining with partial least squares discriminant analysis (PLS-DA), 16 biomarkers in rat urine were identified and eight of them were related to the pathway of energy metabolism. Among the regulated pathways, the citric acid cycle related network was acutely perturbed. The metabolomic results not only supplied a systematic view of the development and progression of MI but also provided the theoretical basis for the prevention or treatment of MI. The developed method was also used to analyze the therapeutic effects of a traditional Chinese medicine (TCM) named Shexiang Baoxin Pill (SBP), a widely used anti-MI medicine in clinics. The results showed that SBP administration could provide satisfactory effects on MI through partially regulating the perturbed pathway of energy metabolism.

Troglitazone-activated PPARγ Inhibits LPS-induced Lung Alveolar Type II Epithelial Cells Injuries Via TNF-α

Molecular Biology Reports. Nov, 2011  |  Pubmed ID: 21153920

Acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) are common syndromes characterized by diffuse, acute injury to the alveolar epithelium and pulmonary vascular endothelial cells, with high mortality rate for there are no effective pharmacological therapies. Peroxisome proliferators-activated receptor γ (PPARγ), a member of the nuclear hormone receptor superfamily of ligand-activated transcription factors, is ubiquitously expressed within the lung. Recent studies have indicated PPARγ can protect lung tissue and alleviate pulmonary inflammatory injury. But no studies examined whether PPARγ agonists can protect the alveolar epithelial cells cultured in vitro. We observed the protective effect of PPARγ in LPS-induced alveolar type II epithelial cells injury. The results showed troglitazone-activated PPARγ could inhibit the production of TNF-α, one of the most important inflammatory factors, and then increased the expression of surfactant-associated protein A (SP-A) and attenuate the apoptosis of alveolar type II epithelial cells. Our results suggest that PPARγ may have a potential therapeutic effect on ALI.

[Study on Differentiation of Rat Adipose Tissue-derived Stromal Cells into Schwann-like Cells]

Zhongguo Ying Yong Sheng Li Xue Za Zhi = Zhongguo Yingyong Shenglixue Zazhi = Chinese Journal of Applied Physiology. Nov, 2011  |  Pubmed ID: 22295505

To investigate the phenotypic, molecular and biological characteristics of adipose tissue-derived stromal cells (ADSCs) differentiated alonely a Schwann cells (SCs) lineage and to provide a new cells' seed source for nerve tissue engineering or cell therapy.

Plasma Pharmacochemistry Based Approach to Screening Potential Bioactive Components in Huang-Lian-Jie-Du-Tang Using High Performance Liquid Chromatography Coupled with Mass Spectrometric Detection

Journal of Ethnopharmacology. Aug, 2011  |  Pubmed ID: 21856396

ETHNOPHARMACOLOGICAL RELEVANCE: Huang-Lian-Jie-Du-Tang (HLJDT), a classic prescription of traditional Chinese medicine (TCM), has been used in clinical over 1700 years for the treatment of gastrointestinal disorders, cardiovascular diseases and Alzheimer disease. But the active components of HLJDT were ambiguous, which seriously restricted its clinical application. MATERIALS AND METHODS: The methodology of plasma pharmacochemistry was applied to screen the bioactive components in HLJDT. A reliable LC/MS system was established for detecting the prototype compounds and metabolites in dosed plasma after oral administration of HLJDT. By comparative analysis of the chemical profiles of HLJDT extracts, blank plasma and dosed plasma, potential bioactive compounds in HLJDT may be discovered. RESULTS: By comparing the retention time, MS and MS/MS spectra with those of reference standard and literature data, 30 components including 22 prototype compounds and 8 metabolites from HLJDT were discovered as potential bioactive components in rat plasma. CONCLUSIONS: A reliable and effective method was established to screen the potential bioactive components in the formula of HLJDT, which provided useful information for the further study of action mechanism of HLJDT.

Biocompatibility Evaluation of Electrospun Aligned Poly (propylene Carbonate) Nanofibrous Scaffolds with Peripheral Nerve Tissues and Cells in Vitro

Chinese Medical Journal. Aug, 2011  |  Pubmed ID: 21933569

Peripheral nerve regeneration across large gaps is clinically challenging. Scaffold design plays a pivotal role in nerve tissue engineering. Recently, nanofibrous scaffolds have proven a suitable environment for cell attachment and proliferation due to similarities of their physical properties to natural extracellular matrix. Poly(propylene carbonate) (PPC) nanofibrous scaffolds have been investigated for vascular tissue engineering. However, no reports exist of PPC nanofibrous scaffolds for nerve tissue engineering. This study aimed to evaluate the potential role of aligned and random PPC nanofibrous scaffolds as substrates for peripheral nerve tissue and cells in nerve tissue engineering.

The Cutoff Protein Regulates PiRNA Cluster Expression and PiRNA Production in the Drosophila Germline

The EMBO Journal. Nov, 2011  |  Pubmed ID: 21952049

In a broad range of organisms, Piwi-interacting RNAs (piRNAs) have emerged as core components of a surveillance system that protects the genome by silencing transposable and repetitive elements. A vast proportion of piRNAs is produced from discrete genomic loci, termed piRNA clusters, which are generally embedded in heterochromatic regions. The molecular mechanisms and the factors that govern their expression are largely unknown. Here, we show that Cutoff (Cuff), a Drosophila protein related to the yeast transcription termination factor Rai1, is essential for piRNA production in germline tissues. Cuff accumulates at centromeric/pericentromeric positions in germ-cell nuclei and strongly colocalizes with the major heterochromatic domains. Remarkably, we show that Cuff is enriched at the dual-strand piRNA cluster 1/42AB and is likely to be involved in regulation of transcript levels of similar loci dispersed in the genome. Consistent with this observation, Cuff physically interacts with the Heterochromatin Protein 1 (HP1) variant Rhino (Rhi). Our results unveil a link between Cuff activity, heterochromatin assembly and piRNA cluster expression, which is critical for stem-cell and germ-cell development in Drosophila.

A Comparison of RNA-Seq and High-density Exon Array for Detecting Differential Gene Expression Between Closely Related Species

Nucleic Acids Research. Jan, 2011  |  Pubmed ID: 20864445

RNA-Seq has emerged as a revolutionary technology for transcriptome analysis. In this article, we report a systematic comparison of RNA-Seq and high-density exon array for detecting differential gene expression between closely related species. On a panel of human/chimpanzee/rhesus cerebellum RNA samples previously examined by the high-density human exon junction array (HJAY) and real-time qPCR, we generated 48.68 million RNA-Seq reads. Our results indicate that RNA-Seq has significantly improved gene coverage and increased sensitivity for differentially expressed genes compared with the high-density HJAY array. Meanwhile, we observed a systematic increase in the RNA-Seq error rate for lowly expressed genes. Specifically, between-species DEGs detected by array/qPCR but missed by RNA-Seq were characterized by relatively low expression levels, as indicated by lower RNA-Seq read counts, lower HJAY array expression indices and higher qPCR raw cycle threshold values. Furthermore, this issue was not unique to between-species comparisons of gene expression. In the RNA-Seq analysis of MicroArray Quality Control human reference RNA samples with extensive qPCR data, we also observed an increase in both the false-negative rate and the false-positive rate for lowly expressed genes. These findings have important implications for the design and data interpretation of RNA-Seq studies on gene expression differences between and within species.

New Oxides Showing an Intense Orange Color Based on Fe3+ in Trigonal-bipyramidal Coordination

Inorganic Chemistry. Jul, 2011  |  Pubmed ID: 21627150

Hexagonal YIn(1-x)Fe(x)O(3) phases have been prepared and characterized. The coordination for the In/Fe site in this structure is trigonal-bipyramidal. The colors of the phases change from yellow to orange to dark red with increasing Fe content. Magnetic measurements confirm high-spin Fe(3+) for all phases.

Fyn Requires HnRNPA2B1 and Sam68 to Synergistically Regulate Apoptosis in Pancreatic Cancer

Carcinogenesis. Oct, 2011  |  Pubmed ID: 21642356

The Src family kinase Fyn, heterogenous nuclear ribonucleoprotein (HnRNP) A2B1 and Sam68 are thought to be associated with the metastasis of tumors, but their roles in the regulation of apoptosis remain unclear. This study investigated the role of Fyn and its potential relationship with HnRNPA2B1 and Sam68 in the regulation of apoptosis in pancreatic cancer. Experimental design. We examined both the activity of Fyn and the expression of HnRNPA2B1 in human pancreatic cancer tissues and systematically investigated the apoptotic mechanisms induced by Fyn activity using multiple experimental approaches.

Molecular Basis of the Tarantula Toxin Jingzhaotoxin-III (β-TRTX-Cj1α) Interacting with Voltage Sensors in Sodium Channel Subtype Nav1.5

FASEB Journal : Official Publication of the Federation of American Societies for Experimental Biology. Sep, 2011  |  Pubmed ID: 21665957

With conserved structural scaffold and divergent electrophysiological functions, animal toxins are considered powerful tools for investigating the basic structure-function relationship of voltage-gated sodium channels. Jingzhaotoxin-III (β-TRTX-Cj1α) is a unique sodium channel gating modifier from the tarantula Chilobrachys jingzhao, because the toxin can selectively inhibit the activation of cardiac sodium channel but not neuronal subtypes. However, the molecular basis of JZTX-III interaction with sodium channels remains unknown. In this study, we showed that JZTX-III was efficiently expressed by the secretory pathway in yeast. Alanine-scanning analysis indicated that 2 acidic residues (Asp1, Glu3) and an exposed hydrophobic patch, formed by 4 Trp residues (residues 8, 9, 28 and 30), play important roles in the binding of JZTX-III to Nav1.5. JZTX-III docked to the Nav1.5 DIIS3-S4 linker. Mutations S799A, R800A, and L804A could additively reduce toxin sensitivity of Nav1.5. We also demonstrated that the unique Arg800, not emerging in other sodium channel subtypes, is responsible for JZTX-III selectively interacting with Nav1.5. The reverse mutation D816R in Nav1.7 greatly increased the sensitivity of the neuronal subtype to JZTX-III. Conversely, the mutation R800D in Nav1.5 decreased JZTX-III's IC₅₀ by 72-fold. Therefore, our results indicated that JZTX-III is a site 4 toxin, but does not possess the same critical residues on sodium channels as other site 4 toxins. Our data also revealed the underlying mechanism for JZTX-III to be highly specific for the cardiac sodium channel.

Genetic and Marine Cyclonic Eddy Analyses on the Largest Macroalgal Bloom in the World

Environmental Science & Technology. Jul, 2011  |  Pubmed ID: 21699243

In 2008, a massive Ulva prolifera bloom, with a 3-million-ton biomass covering an area of 1.29 × 10(4) km(2) at its largest, suddenly appeared from May to July in South Yellow Sea. The mechanism behind the rapid growth of these seaweeds was investigated. Molecular phylogenetic analysis of free-floating algal samples from the Yellow Sea suggested that U. prolifera belong to one population, and that temporary cyclonic eddies in the Yellow Sea in late spring and early summer may help promote the proliferation of this bloom by providing seaweeds with sufficient growth time, abundant nutrition, and favorable habitats. The initial investigation on the relationship between marine cyclonic eddies and the route of free-floating algae extends our knowledge on how the emergence of free-floating macroalgal blooms in coastal areas could yield a large biomass.

Tuning the Electrical Transport Properties of N-type CdS Nanowires Via Ga Doping and Their Nano-optoelectronic Applications

Physical Chemistry Chemical Physics : PCCP. Aug, 2011  |  Pubmed ID: 21709907

Gallium-doped n-type CdS nanowires (NWs) were successfully synthesized via a thermal evaporation method. The conductivities of the CdS NWs were dramatically improved by nearly nine orders of magnitude after Ga doping, and could be further tuned over a wide range by adjusting the doping level. High-performance metal-insulator-semiconductor field-effect transistors (MISFETs) were constructed based on the single CdS : Ga NW with high-κ Si(3)N(4) dielectrics and top-gate geometries. In contrast to back-gate FETs, the MISFETs revealed a substantial improvement in device performance. Nano-light emitting diodes (nanoLEDs) were fabricated from the CdS : Ga NWs by using a n-NW/p(+)-Si substrate hybrid device structure. The nanoLEDs showed a bright yellow emission at a low forward bias. It is expected that the Ga-doped CdS NWs with controlled electrical transport properties will have important applications in nano-optoelectronic devices.

Photo- and Electroluminescence in Thin Films of Covalently Bonded Azomethin-zinc/SiO2 Hybrid Materials

Dalton Transactions (Cambridge, England : 2003). Sep, 2011  |  Pubmed ID: 21713290

We report the design and chemical synthesis of covalently bonded azomethin-zinc/SiO(2) hybrid transparent thin films with photoluminescent and electroluminescent emissions in condensed solid state by a sol-gel approach.

[In Vitro Cartilage Tissue Engineering with Cartilage Extracellular Matrix-derived Porous Scaffolds and Bone Marrow Mesenchymal Stem Cells]

Zhonghua Yi Xue Za Zhi. May, 2011  |  Pubmed ID: 21756767

To develop a novel cartilage ECM-derived porous scaffold (CEDPS) and investigate the attachment, proliferation and distribution of bone marrow mesenchymal stem cells (BMSCs) cultured in vitro within the scaffolds.

Siva1 Suppresses Epithelial-mesenchymal Transition and Metastasis of Tumor Cells by Inhibiting Stathmin and Stabilizing Microtubules

Proceedings of the National Academy of Sciences of the United States of America. Aug, 2011  |  Pubmed ID: 21768358

Epithelial-mesenchymal transition (EMT) enables epithelial cells to acquire motility and invasiveness that are characteristic of mesenchymal cells. It plays an important role in development and tumor cell metastasis. However, the mechanisms of EMT and their dysfunction in cancer cells are still not well understood. Here we report that Siva1 interacts with stathmin, a microtubule destabilizer. Siva1 inhibits stathmin's activity directly as well as indirectly through Ca(2+)/calmodulin-dependent protein kinase II-mediated phosphorylation of stathmin at Ser16. Via the inhibition of stathmin, Siva1 enhances the formation of microtubules and impedes focal adhesion assembly, cell migration, and EMT. Low levels of Siva1 and Ser16-phosphorylated stathmin correlate with high metastatic states of human breast cancer cells. In mouse models, knockdown of Siva1 promotes cancer dissemination, whereas overexpression of Siva1 inhibits it. These results suggest that microtubule dynamics are critical for EMT. Furthermore, they reveal an important role for Siva1 in suppressing cell migration and EMT and indicate that down-regulation of Siva1 may contribute to tumor cell metastasis.

Widespread Establishment and Regulatory Impact of Alu Exons in Human Genes

Proceedings of the National Academy of Sciences of the United States of America. Feb, 2011  |  Pubmed ID: 21282640

The Alu element has been a major source of new exons during primate evolution. Thousands of human genes contain spliced exons derived from Alu elements. However, identifying Alu exons that have acquired genuine biological functions remains a major challenge. We investigated the creation and establishment of Alu exons in human genes, using transcriptome profiles of human tissues generated by high-throughput RNA sequencing (RNA-Seq) combined with extensive RT-PCR analysis. More than 25% of Alu exons analyzed by RNA-Seq have estimated transcript inclusion levels of at least 50% in the human cerebellum, indicating widespread establishment of Alu exons in human genes. Genes encoding zinc finger transcription factors have significantly higher levels of Alu exonization. Importantly, Alu exons with high splicing activities are strongly enriched in the 5'-UTR, and two-thirds (10/15) of 5'-UTR Alu exons tested by luciferase reporter assays significantly alter mRNA translational efficiency. Mutational analysis reveals the specific molecular mechanisms by which newly created 5'-UTR Alu exons modulate translational efficiency, such as the creation or elongation of upstream ORFs that repress the translation of the primary ORFs. This study presents genomic evidence that a major functional consequence of Alu exonization is the lineage-specific evolution of translational regulation. Moreover, the preferential creation and establishment of Alu exons in zinc finger genes suggest that Alu exonization may have globally affected the evolution of primate and human transcriptomes by regulating the protein production of master transcriptional regulators in specific lineages.

P53 Regulates Biosynthesis Through Direct Inactivation of Glucose-6-phosphate Dehydrogenase

Nature Cell Biology. Mar, 2011  |  Pubmed ID: 21336310

Cancer cells consume large quantities of glucose and primarily use glycolysis for ATP production, even in the presence of adequate oxygen. This metabolic signature (aerobic glycolysis or the Warburg effect) enables cancer cells to direct glucose to biosynthesis, supporting their rapid growth and proliferation. However, both causes of the Warburg effect and its connection to biosynthesis are not well understood. Here we show that the tumour suppressor p53, the most frequently mutated gene in human tumours, inhibits the pentose phosphate pathway (PPP). Through the PPP, p53 suppresses glucose consumption, NADPH production and biosynthesis. The p53 protein binds to glucose-6-phosphate dehydrogenase (G6PD), the first and rate-limiting enzyme of the PPP, and prevents the formation of the active dimer. Tumour-associated p53 mutants lack the G6PD-inhibitory activity. Therefore, enhanced PPP glucose flux due to p53 inactivation may increase glucose consumption and direct glucose towards biosynthesis in tumour cells.

Experimental Animal Models of Osteonecrosis

Rheumatology International. Aug, 2011  |  Pubmed ID: 21340568

Osteonecrosis (ON) or avascular necrosis (AVN) is a common bone metabolic disorder, mostly affecting femoral head. Although many biological, biophysical, and surgical methods have been tested to preserve the femoral head with ON, none has been proven fully satisfactory. It lacks consensus on an optimal approach for treatment. This is due, at least in part, to the lack of ability to systematically compare treatment efficacy using an ideal animal model that mimics full-range osteonecrosis of femoral head (ONFH) in humans with high incidence of joint collapse accompanied by reparative reaction adjacent to the necrotic bone in a reproducible and accessible way. A number of preclinical animal ON models have been established for testing potential efficacy of various modalities developed for prevention and treatment of ON before introduction into clinics for potential applications. This paper describes a number of different methods for creating animal experimental ON models. Advantages and disadvantages of such models are also discussed as reference for future research in battle against this important medical condition.

Charge State of Gold Nanoparticles Supported on Titania Under Oxygen Pressure

Angewandte Chemie (International Ed. in English). Mar, 2011  |  Pubmed ID: 21351333

Antitumor Activity of Mixed Heat Shock Protein/peptide Vaccine and Cyclophosphamide Plus Interleukin-12 in Mice Sarcoma

Journal of Experimental & Clinical Cancer Research : CR. 2011  |  Pubmed ID: 21352555

The immune factors heat shock protein (HSP)/peptides (HSP/Ps) can induce both adaptive and innate immune responses. Treatment with HSP/Ps in cancer cell-bearing mice and cancer patients revealed antitumor immune activity. We aimed to develop immunotherapy strategies by vaccination with a mixture of HSP/Ps (mHSP/Ps, HSP60, HSP70, Gp96 and HSP110) enhanced with cyclophosphamide (CY) and interleukin-12 (IL-12).

[Influence of Aligned Electrospinning Poly (propylene Carbonate) on Axonal Growth of Dorsal Root Ganglion in Vitro]

Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi = Zhongguo Xiufu Chongjian Waike Zazhi = Chinese Journal of Reparative and Reconstructive Surgery. Feb, 2011  |  Pubmed ID: 21427845

Poly (propylene carbonate) (PPC), a newly reported polymer, has good biodegradability and biocompatibility. To explore the feasibility of using electrospinning PPC materials in nerve tissue engineering, and to observe the effect of aligned and random PPC materials on axonal growth of rat dorsal root ganglions (DRGs) in vitro.

Antibiofilm Activity of an Exopolysaccharide from Marine Bacterium Vibrio Sp. QY101

PloS One. 2011  |  Pubmed ID: 21490923

Bacterial exopolysaccharides have always been suggested to play crucial roles in the bacterial initial adhesion and the development of complex architecture in the later stages of bacterial biofilm formation. However, Escherichia coli group II capsular polysaccharide was characterized to exert broad-spectrum biofilm inhibition activity. In this study, we firstly reported that a bacterial exopolysaccharide (A101) not only inhibits biofilm formation of many bacteria but also disrupts established biofilm of some strains. A101 with an average molecular weight of up to 546 KDa, was isolated and purified from the culture supernatant of the marine bacterium Vibrio sp. QY101 by ethanol precipitation, iron-exchange chromatography and gel filtration chromatography. High performance liquid chromatography traces of the hydrolyzed polysaccharides showed that A101 is primarily consisted of galacturonic acid, glucuronic acid, rhamnose and glucosamine. A101 was demonstrated to inhibit biofilm formation by a wide range of Gram-negative and Gram-positive bacteria without antibacterial activity. Furthermore, A101 displayed a significant disruption on the established biofilm produced by Pseudomonas aeruginosa, but not by Staphylococcus aureus. Importantly, A101 increased the aminoglycosides antibiotics' capability of killing P. aeruginosa biofilm. Cell primary attachment to surfaces and intercellular aggregates assays suggested that A101 inhibited cell aggregates of both P. aeruginosa and S. aureus, while the cell-surface interactions inhibition only occurred in S. aureus, and the pre-formed cell aggregates dispersion induced by A101 only occurred in P. aeruginosa. Taken together, these data identify the antibiofilm activity of A101, which may make it potential in the design of new therapeutic strategies for bacterial biofilm-associated infections and limiting biofilm formation on medical indwelling devices. The found of A101 antibiofilm activity may also promote a new recognition about the functions of bacterial exopolysaccharides.

Repair of Nerve Defect with Acellular Nerve Graft Supplemented by Bone Marrow Stromal Cells in Mice

Microsurgery. Jul, 2011  |  Pubmed ID: 21503972

The acellular nerve graft that can provide internal structure and extracellular matrix components of the nerve is an alternative for repair of peripheral nerve defects. However, results of the acellular nerve grafting for nerve repair still remain inconsistent. This study aimed to investigate if supplementing bone marrow mesenchymal stromal cells (MSCs) could improve the results of nerve repair with the acellular nerve graft in a 10-mm sciatic nerve defect model in mice. Eighteen mice were divided into three groups (n = 6 for each group) for nerve repairs with the nerve autograft, the acellular nerve graft, and the acellular nerve graft by supplemented with MSCs (5 × 10(5)) fibrin glue around the graft. The mouse static sciatic index was evaluated by walking-track testing every 2 weeks. The weight preservation of the triceps surae muscles and histomorphometric assessment of triceps surae muscles and repaired nerves were examined at week 8. The results showed that the nerve repair by the nerve autografting obtained the best functional recovery of limb. The nerve repair with the acellular nerve graft supplemented with MSCs achieved better functional recovery and higher axon number than that with the acellular nerve graft alone at week 8 postoperatively. The results indicated that supplementing MSCs might help to improve nerve regeneration and functional recovery in repair of the nerve defect with the acellular nerve graft.

4-(1-Ethyl-1H-1,3-benzimidazol-2-yl)-N,N-diphenyl-aniline Monohydrate

Acta Crystallographica. Section E, Structure Reports Online. 2011  |  Pubmed ID: 21523087

In the title compound, C(27)H(23)N(3)O·H(2)O, the benzimidazole ring system has an r.m.s. deviation of 0.0071 Å and makes dihedral angles of 34.51 (2), 55.22 (3) and 41.05 (5)° with the central and N-bonded phenyl rings, respectively. In the crystal, the water mol-ecular is connected to the organic mol-ecule by inter-molecular O-H⋯N hydrogen bonds. Weak inter-molecular C-H⋯O hydrogen bonds also occur.

OLIG Gene Targeting in Human Pluripotent Stem Cells for Motor Neuron and Oligodendrocyte Differentiation

Nature Protocols. May, 2011  |  Pubmed ID: 21527921

Pluripotent stem cells can be genetically labeled to facilitate differentiation studies. In this paper, we describe a gene-targeting protocol to knock in a GFP cassette into key gene loci in human pluripotent stem cells (hPSCs), and then use the genetically tagged hPSCs to guide in vitro differentiation, immunocytochemical and electrophysiological profiling and in vivo characterization after cell transplantation. The Olig transcription factors have key roles in the transcription regulatory pathways for the genesis of motor neurons (MNs) and oligodendrocytes (OLs). We have generated OLIG2-GFP hPSC reporter lines that reliably mark MNs and OLs for monitoring their sequential differentiation from hPSCs. The expression of the GFP reporter recapitulates the endogenous expression of OLIG genes. The in vitro characterization of fluorescence-activated cell sorting-purified cells is consistent with cells of the MN or OL lineages, depending on the stages at which they are collected. This protocol is efficient and reliable and usually takes 5-7 months to complete. The genetic tagging-differentiation methodology used herein provides a general framework for similar work for differentiation of hPSCs into other lineages.

Draft Genome Sequence of the Marine Bacterium Streptomyces Griseoaurantiacus M045, Which Produces Novel Manumycin-type Antibiotics with a PABA Core Component

Journal of Bacteriology. Jul, 2011  |  Pubmed ID: 21551298

Streptomyces griseoaurantiacus M045, isolated from marine sediment, produces manumycin and chinikomycin antibiotics. Here we present a high-quality draft genome sequence of S. griseoaurantiacus M045, the first marine Streptomyces species to be sequenced and annotated. The genome encodes several gene clusters for biosynthesis of secondary metabolites and has provided insight into genomic islands linking secondary metabolism to functional adaptation in marine S. griseoaurantiacus M045.

Concise Review: Quiescent and Active States of Endogenous Adult Neural Stem Cells: Identification and Characterization

Stem Cells (Dayton, Ohio). Jun, 2011  |  Pubmed ID: 21557389

The adult mammalian central nervous system (CNS) lacks the capacity for regeneration, making it a highly sought-after topic for researchers. The identification of neural stem cells (NSCs) in the adult CNS wiped out a long-held dogma that the adult brain contains a set number of neurons and is incapable of replacing them. The discovery of adult NSCs (aNSCs) stoked the fire for researchers who dream of brain self-repair. Unfortunately, the quiescent nature and limited plasticity of aNSCs diminish their regenerative potential. Recent studies evaluating aNSC plasticity under pathological conditions indicate that a switch from quiescent to active aNSCs in neurogenic regions plays an important role in both repairing the damaged tissue and preserving progenitor pools. Here, we summarize the most recent findings and present questions about characterizing the active and quiescent aNSCs in major neurogenic regions, and factors for maintaining their active and quiescent states, hoping to outline an emerging view for promoting the endogenous aNSC-based regeneration.

[Construction of Staphylococcus Aureus RN6390 Hmp Gene Mutant and Analysis of NO Sensitivity]

Wei Sheng Wu Xue Bao = Acta Microbiologica Sinica. Feb, 2011  |  Pubmed ID: 21574380

To investigate the function of flavohaemoglobin (HMP) in Staphylococcus aureus RN6390 under the nitrification pressure, we constructed the hmp gene deletion mutant of RN6390 strain.

Molecular Identification and Phylogenetic Analysis of Trichinella Isolates from Different Provinces in Mainland China

Parasitology Research. Feb, 2012  |  Pubmed ID: 21773771

Polymerase chain reaction (PCR) and sequencing are useful for species identification of Trichinella spp., especially when their morphological characteristics useful for identifying taxa are lacking. In the present study, nine Trichinella isolates from different provinces in mainland China were identified by the PCR-based method using the 5S ribosomal DNA intergene spacer region (5S ISR) and the mitochondrial large subunit ribosomal DNA genes as molecular markers. The results indicated that eight isolates originating from domestic pigs and one isolate originating from civet cat (Paguma larvata) showed identical DNA banding pattern to Trichinella spiralis. Sequence analysis of the 5S ISR gene further confirmed that the nine Trichinella isolates were T. spiralis and revealed the intraspecies genetic variation within T. spiralis.

Comparison of Artificial Digestion and Baermann's Methods for Detection of Trichinella Spiralis Pre-encapsulated Larvae in Muscles with Low-level Infections

Foodborne Pathogens and Disease. Jan, 2012  |  Pubmed ID: 21988397

Artificial digestion method is widely used for the detection of Trichinella larvae (mainly the mature larvae, e.g., encapsulated larvae in encapsulated Trichinella) in meat. The previous studies demonstrated that Trichinella spiralis pre-encapsulated larvae (PEL) at 14-18 days postinfection (dpi) had the infectivity to new hosts. However, to our knowledge, there is no report on the detection methods of PEL in meat. The purpose of this study was to compare the efficiency of artificial digestion and Baermann's methods for detection of T. spiralis PEL in meat, and to test the factors affecting the sensitivity of the two methods. Forty-five male Kunming mice were randomly divided into 3 groups (15 mice per group), and each group of mice was orally inoculated with 20, 10, or 5 muscle larvae of T. spiralis, respectively. All infected mice were slaughtered at 18 dpi, and the muscles were minced. The digestion method that was recommended by International Commission on Trichinellosis and Baermann's method were used to detect the PEL in the infected mice. The detection rate of PEL in both mice infected with 20 muscle larvae by digestion and Baermann's method was 100% (15/15); the detection rates of PEL in mice infected with 10 larvae by the two methods just mentioned were 93.33% (14/15) and 100% (15/15), respectively; when the mice infected with 5 larvae were tested, the different detection rate of PEL was achieved by using digestion method (63.33%) and Baermann's method (100%). Additionally, the number of PEL collected from the mice infected with 20, 10, or 5 larvae by Baermann's method was greater than that by digestion methods. The mortality of PEL increased along with the prolongation of digestion duration, because the PEL were not resistant to enzymatic digestion. The results revealed that the Baermann's method is superior to the digestion methods for detection of T. spiralis PEL in muscle samples with low-level infections.

Cynandione A Mitigates Ischemic Injuries in Rats with Cerebral Ischemia

Journal of Neurochemistry. Feb, 2012  |  Pubmed ID: 22309483

Cynandione A, an acetophenone from the roots of Cynanchum auriculatum and other species in the genus attenuates neurotoxicity of a variety of neurotoxic agents such as L-glutamate in vitro. Here, we sought to further characterize the neuroprotective effects of cynandione A and other acetophenones from the roots of C. auriculatum in pheochromocytoma tumor cell line PC12 and investigate whether cynandione A protected against ischemic injuries in rats with experimentally induced cerebral ischemia. Viability assays using the WST-8 method and LDH release assays showed that cynandione A dose-dependently attenuated glutamate-induced cytotoxicity. Comparative proteomic analysis by two-dimensional gel electrophoresis and MALDI-TOF MS/MS of PC12 cells treated with cynandione A showed 10 μM cynandione A caused broad changes in protein expression in PC12 cells including downregulation of high mobility group box 1 (HMGB1) and dihydropyrimidinase-like 2 (DPYSL2). Immunoblotting studies showed that 10 μM cynandione A aborted glutamate-induced increase in DPYSL2 and HMGB1 levels in PC12 cells and 30 mg/kg cynandione A also attenuated the rise in HMGB1 levels and mitigated DPYSL2 cleavage in brain tissues of rats with cerebral ischemia. Furthermore, rats with cerebral ischemia treated with 30 mg/kg cynandione A exhibited markedly improved neurological deficit scores at 24 and 72 h compared with control and a 7.2% reduction in cerebral infarction size at 72 h (P < 0.05 vs. control). Our findings demonstrated that cynandione A mitigated ischemic injuries and should be further explored as a neuroprotective agent for ischemic stroke. © 2012 The Authors Journal of Neurochemistry © 2012 International Society for Neurochemistry.

A Functional Variant of the Collagen Type III Alpha1 Gene Modify Risk of Sporadic Intracranial Aneurysms

Human Genetics. Jan, 2012  |  Pubmed ID: 22241462

Abnormalities in type III collagen in the arterial walls cause certain familial intracranial aneurysms (IAs); however, it remains unknown whether COL3A1 variants contribute to the risk of sporadic IAs. To study whether COL3A1 variants are associated with sporadic IAs, the association of COL3A1 variants with sporadic IAs was tested in 298 cases and 488 controls, replicated in an independent population of 192 cases and 1,690 controls, and further verified in 633 patients with intra-cerebral hemorrhage, 1,074 hypertensives, and 1,883 controls. We found that allele A of SNP rs1800255 conferred a 1.71-fold increased risk for IAs (adjusted odds ratio: OR = 1.71, 95% confidence interval: CI 1.19-2.45, P = 0.004) and results in an amino acid change of Ala698Thr, which led to a lower thermal stability of the peptide. These results were confirmed in the independent study. The associations were independent of the presence of hemorrhagic stroke and hypertension. These results support the view that the functional variant of COL3A1 is genetic risk factors for IAs in the Chinese population.

Vapor Detection Enabled by Self-assembled Colloidal Photonic Crystals

Journal of Colloid and Interface Science. Mar, 2012  |  Pubmed ID: 22249160

Here we report the sensitive and reversible detection of vapors by using self-assembled colloidal photonic crystals. The condensation of various vapors in the interstitials of silica colloidal photonic crystals leads to red-shift and amplitude reduction of optical stop bands. A linear relationship between wavelength shift and vapor partial pressure has been observed for a variety of vapors including ethanol, water, and toluene. Importantly, the sensitivity of colloidal photonic crystal-based vapor detectors can be improved by nearly two orders of magnitude by using a new full-peak analysis technique that takes advantage of the manifest amplitude reduction of optical stop bands during vapor condensation. Optical simulation based on a scalar-wave approximation model shows that the predicted optical responses during vapor condensation in colloidal photonic crystals agree well with experimental results. The condensation of vapors between submicrometer-scale microspheres, a topic that has received little examination, has also been investigated by both experiments and theoretical calculations. Predictions based on a modified Kelvin equation match with the experiments for a wide range of vapor partial pressures.

2-(2-Nitro-anilino)benzoic Acid

Acta Crystallographica. Section E, Structure Reports Online. Jan, 2012  |  Pubmed ID: 22259495

In the title compound, C(13)H(10)N(2)O(4), the nitro N atom deviates by 0.031 (2) Å from the plane of the benzene ring to which it is attached. The aromatic rings are oriented at a dihedral angle of 50.6 (1)°. An intra-molecular N-H⋯O hydrogen bond occurs. In the crystal, inversion dimers are formed by pairs of O-H⋯O inter-actions.

Differentiating Human Stem Cells into Neurons and Glial Cells for Neural Repair

Frontiers in Bioscience : a Journal and Virtual Library. 2012  |  Pubmed ID: 22201733

Research on the biology of adult stem cells, embryonic stem cells and induced pluripotent stem cells, as well as cell-based strategies for treating nervous system disorders has begun to create the hope that these cells may be used for therapy in humans after injury or disease. In animal models of neurological diseases, transplantation of stem cells or their derivatives can improve function not only due to direct replacement of lost neurons or glia, but also by providing trophic support. Despite intense research efforts to translate these studies from the bench to bedside, critical problems remain at several steps in this process. Recent technological advancements in both the derivation of stem cells and their directed differentiation to lineage-committed progenitors have brought us closer to therapeutic applications. Several preclinical studies have already explored the behavior of transplanted cells with respect to proliferation, migration, differentiation and survival, especially in complex pathological disease environments. In this review, we examine the current status, progress, pitfalls, and potential of these stem cell technologies, focusing on directed differentiation of human stem cells into various neural lineages, including dopaminergic neurons, motor neurons, oligodendroglia, microglia, and astroglia, and on advancements in cell-based regenerative strategies for neural repair and criteria for successful therapeutic applications.