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Find video protocols related to scientific articles indexed in Pubmed.
Non-invasive Prenatal Testing for Wilson Disease by Use of Circulating Single-Molecule Amplification and Resequencing Technology (cSMART).
Clin. Chem.
PUBLISHED: 11-08-2014
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Noninvasive prenatal testing (NIPT) for monogenic diseases by use of PCR-based strategies requires precise quantification of mutant fetal alleles circulating in the maternal plasma. The study describes the development and validation of a novel assay termed circulating single-molecule amplification and resequencing technology (cSMART) for counting single allelic molecules in plasma. Here we demonstrate the suitability of cSMART for NIPT, with Wilson Disease (WD) as proof of concept.
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Beyond Branching: Multi-knot Structured Polymer for Gene Delivery.
Biomacromolecules
PUBLISHED: 11-07-2014
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Polymer-based transfection vectors are increasingly becoming the preferred alternative to viral vectors thanks to their safety and ease of production, but low transfection potency has limited their application. Many polycationic vectors show high efficiency in vitro, but their excessive charge density makes them toxic for in vivo applications. Herein, we demonstrate the synthesis of new and unique disulfide-reducible polymeric gene nano-carriers that exhibit significantly enhanced transfection potency and low cytotoxicity, particularly in skin cells, surpassing the efficiency of the well-known transfection reagents Polyethylenimine (PEI) and Lipofectamine®2000. The unique 3D 'multi-knot' vectors were synthesized from in situ deactivation enhanced atom transfer radical (co-)polymerization (DE-ATRP) of multivinyl monomers (MVMs). The high transfection levels and low toxicity of this multi-knot structured polymer in vitro, combined with its ability to mediate collagen VII expression in 3D skin equivalents made from cells of Recessive dystrophic Epidermolysis Bullosa patients, demonstrates its use as a platform nanotechnology which should be investigated further for dermatological disease therapies. Our findings suggest that the marked improvements stem from the dense multi-knot architecture and degradable property, which facilitate both the binding and releasing process of the plasmid DNA.
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Modification-dependent restriction endonuclease, MspJI, flips 5-methylcytosine out of the DNA helix.
Nucleic Acids Res.
PUBLISHED: 09-27-2014
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MspJI belongs to a family of restriction enzymes that cleave DNA containing 5-methylcytosine (5mC) or 5-hydroxymethylcytosine (5hmC). MspJI is specific for the sequence 5(h)mC-N-N-G or A and cleaves with some variability 9/13 nucleotides downstream. Earlier, we reported the crystal structure of MspJI without DNA and proposed how it might recognize this sequence and catalyze cleavage. Here we report its co-crystal structure with a 27-base pair oligonucleotide containing 5mC. This structure confirms that MspJI acts as a homotetramer and that the modified cytosine is flipped from the DNA helix into an SRA-like-binding pocket. We expected the structure to reveal two DNA molecules bound specifically to the tetramer and engaged with the enzyme's two DNA-cleavage sites. A coincidence of crystal packing precluded this organization, however. We found that each DNA molecule interacted with two adjacent tetramers, binding one specifically and the other non-specifically. The latter interaction, which prevented cleavage-site engagement, also involved base flipping and might represent the sequence-interrogation phase that precedes specific recognition. MspJI is unusual in that DNA molecules are recognized and cleaved by different subunits. Such interchange of function might explain how other complex multimeric restriction enzymes act.
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Wilms tumor protein recognizes 5-carboxylcytosine within a specific DNA sequence.
Genes Dev.
PUBLISHED: 09-25-2014
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In mammalian DNA, cytosine occurs in several chemical forms, including unmodified cytosine (C), 5-methylcytosine (5mC), 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC). 5mC is a major epigenetic signal that acts to regulate gene expression. 5hmC, 5fC, and 5caC are oxidized derivatives that might also act as distinct epigenetic signals. We investigated the response of the zinc finger DNA-binding domains of transcription factors early growth response protein 1 (Egr1) and Wilms tumor protein 1 (WT1) to different forms of modified cytosine within their recognition sequence, 5'-GCG(T/G)GGGCG-3'. Both displayed high affinity for the sequence when C or 5mC was present and much reduced affinity when 5hmC or 5fC was present, indicating that they differentiate primarily oxidized C from unoxidized C, rather than methylated C from unmethylated C. 5caC affected the two proteins differently, abolishing binding by Egr1 but not by WT1. We ascribe this difference to electrostatic interactions in the binding sites. In Egr1, a negatively charged glutamate conflicts with the negatively charged carboxylate of 5caC, whereas the corresponding glutamine of WT1 interacts with this group favorably. Our analyses shows that zinc finger proteins (and their splice variants) can respond in modulated ways to alternative modifications within their binding sequence.
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Whole-genome DNA methylation patterns and complex associations with gene structure and expression during flower development in Arabidopsis.
Plant J.
PUBLISHED: 09-24-2014
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Flower development is a complex process requiring proper spatiotemporal expression of numerous genes. Accumulating evidence indicates that epigenetic mechanisms, including DNA methylation, play essential roles in modulating gene expression. However, few studies have examined the relationship between DNA methylation and floral gene expression on a genomic scale. Here we present detailed analyses of DNA methylomes of single-base resolution for three Arabidopsis floral periods: meristems, early flowers, and late flowers. We detected 1.5 million methyl-cytosines and estimated the methylation levels for 24,035 genes. We found that very many cytosine sites were methylated de novo from the meristem to the early flower and many sites were demethylated from early to late flowers. A comparison of the transcriptome data of the same three periods revealed that the methylation and demethylation processes were correlated with expression changes of >3,000 genes, many of which are important for normal flower development. We also found different methylation patterns for three sequence contexts ((m) CG, (m) CHG, (m) CHH) and in different genic regions, potentially playing different roles in gene expression. This article is protected by copyright. All rights reserved.
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The artificial cycle method improves the pregnancy outcome in frozen-thawed embryo transfer: a retrospective cohort study.
Gynecol. Endocrinol.
PUBLISHED: 09-17-2014
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Abstract The aim of this retrospective cohort study was to investigate which preparation method is optimal for frozen-thawed embryo transfer (FET) treatment. Analyses were performed on 3160 FET cycles, including 654 cycles with a natural cycle (NC) protocol and 2506 cycles with an artificial cycle (AC) protocol. The primary outcome measures were the clinical pregnancy rate (CPR) and the live birth rate (LBR) per transfer. The Student's t-test, chi-square test and multiple logistic regression were used for statistical analysis. The CPR per transfer was 49.4% in the NC group and 58.6% in the AC group (OR?=?1.270, 95% CI: 1.037-1.554). The LBR per transfer was 42.2% and 50.8% in the NC and AC groups, respectively (OR?=?1.269, 95% CI: 1.037-1.552). Dividing the patients according to the type of transferred embryos, the CPR (67.3% versus 57.0%, p?
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Transfection of the glial cell line-derived neurotrophic factor gene promotes neuronal differentiation.
Neural Regen Res
PUBLISHED: 09-11-2014
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Glial cell line-derived neurotrophic factor recombinant adenovirus vector-transfected bone marrow mesenchymal stem cells were induced to differentiate into neuron-like cells using inductive medium containing retinoic acid and epidermal growth factor. Cell viability, microtubule-associated protein 2-positive cell ratio, and the expression levels of glial cell line-derived neurotrophic factor, nerve growth factor and growth-associated protein-43 protein in the supernatant were significantly higher in glial cell line-derived neurotrophic factor/bone marrow mesenchymal stem cells compared with empty virus plasmid-transfected bone marrow mesenchymal stem cells. Furthermore, microtubule-associated protein 2, glial cell line-derived neurotrophic factor, nerve growth factor and growth-associated protein-43 mRNA levels in cell pellets were statistically higher in glial cell line-derived neurotrophic factor/bone marrow mesenchymal stem cells compared with empty virus plasmid-transfected bone marrow mesenchymal stem cells. These results suggest that glial cell line-derived neurotrophic factor/bone marrow mesenchymal stem cells have a higher rate of induction into neuron-like cells, and this enhanced differentiation into neuron-like cells may be associated with up-regulated expression of glial cell line-derived neurotrophic factor, nerve growth factor and growth-associated protein-43.
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[Effect of pulse magnetic field on distribution of neuronal action potential].
Sheng Li Xue Bao
PUBLISHED: 08-19-2014
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The biological effect on the organism generated by magnetic field is widely studied. The present study was aimed to observe the change of sodium channel under magnetic field in neurons. Cortical neurons of Kunming mice were isolated, subjected to 15 Hz, 1 mT pulse magnetic stimulation, and then the currents of neurons were recorded by whole-cell patch clamp. The results showed that, under magnetic stimulation, the activation process of Na(+) channel was delayed, and the inactivation process was accelerated. Given the classic three-layer model, the polarization diagram of cell membrane potential distribution under pulse magnetic field was simulated, and it was found that the membrane potential induced was associated with the frequency and intensity of magnetic field. Also the effect of magnetic field-induced current on action potential was simulated by Hodgkin-Huxley (H-H) model. The result showed that the generation of action potential was delayed, and frequency and the amplitudes were decreased when working current was between -1.32 ?A and 0 ?A. When the working current was higher than 0 ?A, the generation frequency of action potential was increased, and the change of amplitudes was not obvious, and when the working current was lower than -1.32 ?A, the time of rising edge and amplitudes of action potential were decreased drastically, and the action potential was unable to generate. These results suggest that the magnetic field simulation can affect the distribution frequency and amplitude of action potential of neuron via sodium channel mediation.
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A high-throughput adrenaline test for the exploration of the catalytic potential of halohydrin dehalogenases in epoxide-ring opening reactions.
Biotechnol. Appl. Biochem.
PUBLISHED: 08-02-2014
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The principle of the adrenaline test for enzymes is based on the quantification of periodate-sensitive reaction products with adrenaline to produce a chromogenic compound adrenochrome that can be easily detected. Here a rapid whole cell-based adrenaline assay for the activity measurement of halohydrin dehalogenases (HHDHs) in nucleophile mediated epoxide-opening reactions is presented. The assay was validated using two types of model reactions (glycidol with nucleophiles, and nitrite with epoxides). Moreover, the reliability of the assay was confirmed by GC analysis. Our results demonstrated that the developed assay is efficient in both library screening and the evaluation of catalytic diversity and specificity of HHDHs. Thus, the assay represents a valuable tool in the evolution of HHDHs for its industrial applications. Moreover, the adrenaline test exhibits a great potential for enzyme assay and could be easily adopted for other suitable enzymes. This article is protected by copyright. All rights reserved.
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Early magnitude estimation for the MW7.9 Wenchuan earthquake using progressively expanded P-wave time window.
Sci Rep
PUBLISHED: 07-25-2014
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More and more earthquake early warning systems (EEWS) are developed or currently being tested in many active seismic regions of the world. A well-known problem with real-time procedures is the parameter saturation, which may lead to magnitude underestimation for large earthquakes. In this paper, the method used to the MW9.0 Tohoku-Oki earthquake is explored with strong-motion records of the MW7.9, 2008 Wenchuan earthquake. We measure two early warning parameters by progressively expanding the P-wave time window (PTW) and distance range, to provide early magnitude estimates and a rapid prediction of the potential damage area. This information would have been available 40?s after the earthquake origin time and could have been refined in the successive 20?s using data from more distant stations. We show the suitability of the existing regression relationships between early warning parameters and magnitude, provided that an appropriate PTW is used for parameter estimation. The reason for the magnitude underestimation is in part a combined effect of high-pass filtering and frequency dependence of the main radiating source during the rupture process. Finally we suggest only using Pd alone for magnitude estimation because of its slight magnitude saturation compared to the ?c magnitude.
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Clostridium difficile carriage in hospitalized cancer patients: a prospective investigation in eastern China.
BMC Infect. Dis.
PUBLISHED: 07-16-2014
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Clostridium difficile carriage has been considered as a potential source for the deadly infection, but its role in cancer patients is still unclear. We aimed to identify the clinical and immunological factors that are related to C. difficile carriage in Chinese cancer patients.
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Integrating novel chemical weapons and evolutionarily increased competitive ability in success of a tropical invader.
New Phytol.
PUBLISHED: 07-08-2014
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The evolution of increased competitive ability (EICA) hypothesis and the novel weapons hypothesis (NWH) are two non-mutually exclusive mechanisms for exotic plant invasions, but few studies have simultaneously tested these hypotheses. Here we aimed to integrate them in the context of Chromolaena odorata invasion. We conducted two common garden experiments in order to test the EICA hypothesis, and two laboratory experiments in order to test the NWH. In common conditions, C. odorata plants from the nonnative range were better competitors but not larger than plants from the native range, either with or without the experimental manipulation of consumers. Chromolaena odorata plants from the nonnative range were more poorly defended against aboveground herbivores but better defended against soil-borne enemies. Chromolaena odorata plants from the nonnative range produced more odoratin (Eupatorium) (a unique compound of C. odorata with both allelopathic and defensive activities) and elicited stronger allelopathic effects on species native to China, the nonnative range of the invader, than on natives of Mexico, the native range of the invader. Our results suggest that invasive plants may evolve increased competitive ability after being introduced by increasing the production of novel allelochemicals, potentially in response to naïve competitors and new enemy regimes.
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Are the duplication cost and Robinson-Foulds distance equivalent?
J. Comput. Biol.
PUBLISHED: 07-02-2014
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In the tree reconciliation approach for species tree inference, a tree that has the minimum reconciliation score for given gene trees is taken as an estimate of the species tree. The scoring models used in existing tree reconciliation methods include the duplication, mutation, and deep coalescence costs. Since existing inference methods all are heuristic, their performances are often evaluated by using the Robinson-Foulds (RF) distance between the true species trees and the estimates output on simulated multi-locus datasets. To better understand these methods, we study the relationships between the duplication cost and the RF distance. We prove that the gap between the duplication cost and the RF distance is unbounded, but the symmetric duplication cost is logarithmically equivalent to the RF distance. The relationships between other reconciliation costs and the RF distance are also investigated.
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Polarization-insensitive resonances with high quality-factors in meta-molecule metamaterials.
Opt Express
PUBLISHED: 07-01-2014
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Achieving narrow resonance is an area of interest within the field of metamaterials. However, only a few studies have investigated the polarization-insensitive resonances. A general principle for improving quality Q-factor of a sharp resonance is still unclear. In this work, we proposed a kind of planar meta-molecule metamaterials, which can exhibit polarization-insensitive resonance with high Q-factor. The proposed structures have a unit cell consisting of four arrayed ring resonant elements with two different sizes. Moreover, the investigation on surface current and two referential simulated structures confirm a principle for improving Q-factor.
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Determining the organ of origin of large pelvic masses in females using multidetector CT angiography and three-dimensional volume rendering CT angiography.
Eur Radiol
PUBLISHED: 06-25-2014
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To study the value of tumour feeding arteries and the ovarian vein in determining the organ of origin of large pelvic tumours in females using multidetector CT.
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A fluorescence glucose sensor based on pH induced conformational switch of i-motif DNA.
Talanta
PUBLISHED: 06-24-2014
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A facile fluorescence biosensor for the detection of glucose is proposed based on the pH-induced conformational switch of i-motif DNA in this paper. Glucose can be oxidized by oxygen (O2) in the presence of glucose oxidase (GOD), and the generated gluconic acid can decrease the pH value of the solution and then induce the fluorophore- and quencher-labeled cytosine-rich single-stranded DNA to fold into a close-packed i-motif structure. As a result, the fluorescence quenching occurs because of the resonance energy transfer between fluorophore and quencher. Based on this working principle, the concentration of glucose can be detected by the decrease of fluorescence density. Under the optimal experimental conditions, the assay shows a linear response range of 5-100 µM for the glucose concentration with a detection limit of 4 µM. This glucose biosensor was applied to determine glucose in real samples successfully, suggesting its potential in the practical applicability.
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The effect of ethanol on cell properties and steroid 1-en-dehydrogenation biotransformation of Arthrobacter simplex.
Biotechnol. Appl. Biochem.
PUBLISHED: 06-11-2014
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Resting cells of Arthrobacter simplex with 1-en-dehydrogenation ability were prepared and treated by ethanol at subinhibitory concentrations (4%-15%, v/v), then added into the ethanol-free system containing low concentration of cortisone acetate (1 g L(-1) ) to produce prednisone acetate by C1,2 dehydrogenation reaction. Results showed that, within the range of ethanol concentration, the initial conversion rate was varied significantly with the concentration of ethanol and the maximum was obtained at 8% (v/v) ethanol, which was increased by 32.6% compared with the control. A series of cell features closely relevant to biotransformation efficiency were further analyzed. It indicated that ethanol acting on cell wall and membrane could be used as a mediator to enhance cell permeability, which facilitated the penetration of substrate across cell barrier within a short time, resulting in the elevated initial conversation rate. The observation of fatty acids composition suggested that the increased unsaturated fatty acids, especially cis-isomers, in the presence of ethanol led to the disorganization of the native arrangement of lipids and thus increased cell permeability. Our findings demonstrated that another facilitation of ethanol was to promote substrate transport into cells by permeabilization, which would provide the guidance in the practical application of organic solvents in steroid biotransformation.
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Structure of 5-hydroxymethylcytosine-specific restriction enzyme, AbaSI, in complex with DNA.
Nucleic Acids Res.
PUBLISHED: 06-03-2014
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AbaSI, a member of the PvuRts1I-family of modification-dependent restriction endonucleases, cleaves deoxyribonucleic acid (DNA) containing 5-hydroxymethylctosine (5hmC) and glucosylated 5hmC (g5hmC), but not DNA containing unmodified cytosine. AbaSI has been used as a tool for mapping the genomic locations of 5hmC, an important epigenetic modification in the DNA of higher organisms. Here we report the crystal structures of AbaSI in the presence and absence of DNA. These structures provide considerable, although incomplete, insight into how this enzyme acts. AbaSI appears to be mainly a homodimer in solution, but interacts with DNA in our structures as a homotetramer. Each AbaSI subunit comprises an N-terminal, Vsr-like, cleavage domain containing a single catalytic site, and a C-terminal, SRA-like, 5hmC-binding domain. Two N-terminal helices mediate most of the homodimer interface. Dimerization brings together the two catalytic sites required for double-strand cleavage, and separates the 5hmC binding-domains by ?70 Å, consistent with the known activity of AbaSI which cleaves DNA optimally between symmetrically modified cytosines ?22 bp apart. The eukaryotic SET and RING-associated (SRA) domains bind to DNA containing 5-methylcytosine (5mC) in the hemi-methylated CpG sequence. They make contacts in both the major and minor DNA grooves, and flip the modified cytosine out of the helix into a conserved binding pocket. In contrast, the SRA-like domain of AbaSI, which has no sequence specificity, contacts only the minor DNA groove, and in our current structures the 5hmC remains intra-helical. A conserved, binding pocket is nevertheless present in this domain, suitable for accommodating 5hmC and g5hmC. We consider it likely, therefore, that base-flipping is part of the recognition and cleavage mechanism of AbaSI, but that our structures represent an earlier, pre-flipped stage, prior to actual recognition.
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Impact of night sleep duration on glycemic and triglyceride levels in Chinese with different glycemic status.
J Diabetes
PUBLISHED: 05-28-2014
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The aim of the present study was to assess the relationship between night sleep duration and glycemic and triglyceride (TG) levels among people with different glycemic status.
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[Comparison of short- and long-term efficacy of three procedures in postoperative digestive tract reconstruction for upper gastric cancer].
Zhonghua Wei Chang Wai Ke Za Zhi
PUBLISHED: 05-27-2014
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To compare the short- and long-term efficacy of three different procedures used for digestive tract reconstruction after radical gastrectomy for upper gastric cancer.
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Ultrathin spinel membrane-encapsulated layered lithium-rich cathode material for advanced Li-ion batteries.
Nano Lett.
PUBLISHED: 05-23-2014
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Lack of high-performance cathode materials has become a technological bottleneck for the commercial development of advanced Li-ion batteries. We have proposed a biomimetic design and versatile synthesis of ultrathin spinel membrane-encapsulated layered lithium-rich cathode, a modification by nanocoating. The ultrathin spinel membrane is attributed to the superior high reversible capacity (over 290 mAh g(-1)), outstanding rate capability, and excellent cycling ability of this cathode, and even the stubborn illnesses of the layered lithium-rich cathode, such as voltage decay and thermal instability, are found to be relieved as well. This cathode is feasible to construct high-energy and high-power Li-ion batteries.
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Antiretroviral therapy and efficacy after virologic failure on first-line boosted protease inhibitor regimens.
Clin. Infect. Dis.
PUBLISHED: 05-19-2014
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Virologic failure (VF) on a first-line ritonavir-boosted protease inhibitor (PI/r) regimen is associated with low rates of resistance, but optimal management after failure is unknown.
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Soluble markers of inflammation and coagulation but not T-cell activation predict non-AIDS-defining morbid events during suppressive antiretroviral treatment.
J. Infect. Dis.
PUBLISHED: 05-01-2014
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Defining the association of non-AIDS-defining events with inflammation and immune activation among human immunodeficiency virus (HIV)-infected persons with antiretroviral therapy (ART)-associated virological suppression is critical to identifying interventions to decrease the occurrence of these events.
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Whole exome sequencing identifies a novel EMD mutation in a Chinese family with dilated cardiomyopathy.
BMC Med. Genet.
PUBLISHED: 04-21-2014
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Variants in the emerin gene (EMD) were implicated in X-linked recessive Emery-Dreifuss muscular dystrophy (EDMD), characterized by early-onset contractures of tendons, progressive muscular weakness and cardiomyopathy. To date, 223 mutations have been reported in EMD gene and the majority of them caused a predominant skeletal muscular phenotype. In this study, we identified a novel deletion mutation in EMD exon 1, which results in almost a complete loss of emerin protein in a large Chinese family. However, the patients suffered severe dilated cardiomyopathy (DCM) but very mild skeletal muscle disorder.
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Predictors of suboptimal CD4 response among women achieving virologic suppression in a randomized antiretroviral treatment trial, Africa.
BMC Infect. Dis.
PUBLISHED: 04-09-2014
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A subset of HIV-1 infected patients starting highly active antiretroviral treatment (HAART) experience suboptimal CD4 response (SCR) despite virologic suppression. We studied the rate of and risk factors for SCR among women starting HAART in the ACTG A5208 study conducted in 7 African countries. 741 HAART-naive women with screening CD4 count <200 cells/?L were randomized to start HAART with Tenofovir/Emtricitabine plus either Nevirapine or Lopinavir/Ritonavir.
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[Expression of miR-146a in colon cancer and its significance].
Nan Fang Yi Ke Da Xue Xue Bao
PUBLISHED: 03-28-2014
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To investigate miR-146a expression in colonic cancer and its clinical implications.
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Real-time study of interactions between cytosine-cytosine pairs in DNA oligonucleotides and silver ions using dual polarization interferometry.
Anal. Chem.
PUBLISHED: 03-26-2014
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The real-time conformational changes of cytosine (C)-rich ssDNA oligonucleotides upon binding with silver ions (Ag(+)) were studied using dual polarization interferometry (DPI). Upon the addition of Ag(+), Ag(+) selectively bound to cytosine-cytosine mismatches and formed C-Ag(+)-C complexes, inducing change of the structure of the C-rich ssDNA from random coil conformation to duplex conformation, whereas the control ssDNA without cytosine-cytosine mismatches had no such signal, which was consistent with circular dichroism (CD) characterization. The conformational change of DNA was reflected on the changes of the mass, thickness, and density values resolved by DPI. The calibration curves showed that as the concentration of Ag(+) increased from 10 nM to 8 ?M, the thickness and mass values increased linearly while the density values decreased linearly. Other metal ions such as K(+), Ca(2+), Na(+), Mg(2+), Zn(2+), Mn(2+), Ni(2+), and Pb(2+) did not interfere with the interaction between Ag(+) and C-rich ssDNA, indicating that this method had a good selectivity. The practical application of this biosensor was also investigated in real samples such as drinking water. Besides, cysteine could specifically capture Ag(+) from C-Ag(+)-C complexes and transformed the structure of the C-rich DNA back from rigid double-stranded conformation to random coil conformation, which allowed cysteine to be detected selectively as well. It is expected that this biosensing strategy may be utilized to study the interaction of DNA with other molecules.
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Targeting IL-6 and RANKL signaling inhibits prostate cancer growth in bone.
Clin. Exp. Metastasis
PUBLISHED: 03-25-2014
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In prostate cancer metastases to bone, cancer cell-derived cytokines stimulate RANKL expression by cells of the osteoblast lineage, which in turn activates osteoclastic bone resorption. However, it is unclear whether cells of the osteoblast lineage signal back to prostate cancer cells, and if so, whether such direct cross-talk can be targeted therapeutically. Using the human prostate cancer cell line, PC3, we identified two novel signalling pathways acting between cells of the osteoblast lineage and cancer cells. First, exposure to RANKL stimulated the expression and release of IL-6 by PC3 cells in vitro (which is known to promote RANKL expression by osteoblasts). Second, treatment of PC3 cells with IL-6 increased the expression of RANK, the cognate receptor of RANKL, and enhanced the RANKL-induced release of IL-6 by PC3 cells. Third, targeted disruption of IL-6 signaling with tocilizumab, a clinically available antibody against the human IL-6 receptor, inhibited skeletal tumor growth in vivo and reduced serum RANKL levels as well as RANK expression by PC3-derived bone tumors. Similar effects were achieved when RANK expression was knocked down in PC3 cells. In contrast, disruption of IL-6 or RANK/RANKL signalling had no effect on PC3 tumor growth in soft tissues, indicating that these signalling pathways act specifically within the bone microenvironment. In conclusion, prostate cancer cells and cells of the osteoblast lineage communicate via two inter-dependent signaling pathways, which through auto-amplification strongly enhance metastatic prostate cancer growth in bone. Both pathways may be targeted for effective therapeutic intervention.
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Docetaxel load biodegradable porous microspheres for the treatment of colorectal peritoneal carcinomatosis.
Int. J. Biol. Macromol.
PUBLISHED: 03-16-2014
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Micro- and nanoparticle formulations are widely used to improve the bioavailability of low solubility drugs. In this study, biodegradable poly(L-lactide acid)-Pluronic L121-poly(L-lactide acid) (PLLA-L121-PLLA) was developed. And then a controlled drug delivery system (CDDS), docetaxel (DOC) loaded PLLA-L121-PLLA porous microsphere (DOC MS) was prepared for colorectal peritoneal carcinomatosis (CRPC) therapy. DOC MS was prepared by DOC and PLLA-L121-PLLA using an oil-in-water emulsion solvent evaporation method. The particle size, morphological characteristics, encapsulation efficiency, in vitro drug release studies and in vitro cytotoxicity of DOC MS have been investigated. In vitro release profile demonstrated a significant difference between rapid release of free DOC and much slower and sustained release of DOC MS. Furthermore, cytotoxicity assay indicated cytotoxicity was increased after DOC was encapsulated into polymeric microspheres. In addition, intraperitoneal administration of DOC MS could effectively suppress growth and metastasis of CT26 peritoneal carcinomatosis in vivo, and prolonged the survival of tumor bearing mice. Immunohistochemistry staining of tumor tissues with Ki-67 revealed that DOC MS induced a stronger anti-tumor effect by increasing apoptosis of tumor cells in contrast to other groups (P<0.05). Thus, our results suggested that DOC MS may have great potential applications in clinic.
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Direct crosstalk between cancer and osteoblast lineage cells fuels metastatic growth in bone via auto-amplification of IL-6 and RANKL signaling pathways.
J. Bone Miner. Res.
PUBLISHED: 03-13-2014
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The bone microenvironment and its modification by cancer and host cell interactions is a key driver of skeletal metastatic growth. Interleukin-6 (IL-6) stimulates receptor activator of NF-?B ligand (RANKL) expression in bone cells, and serum IL-6 levels are associated with poor clinical outcomes in cancer patients. We investigated the effects of RANKL on cancer cells and the role of tumor-derived IL-6 within the bone microenvironment. Using human breast cancer cell lines to induce tumors in the bone of immune-deficient mice, we first determined whether RANKL released by cells of the osteoblast lineage directly promotes IL-6 expression by cancer cells in vitro and in vivo. We then disrupted of IL-6 signaling in vivo either via knockdown of IL-6 in tumor cells or through treatment with specific anti-human or anti-mouse IL-6 receptor antibodies to investigate the tumor effect. Finally, we tested the effect of RANK knockdown in cancer cells on cancer growth. We demonstrate that osteoblast lineage-derived RANKL upregulates secretion of IL-6 by breast cancers in vivo and in vitro. IL-6, in turn, induces expression of RANK by cancer cells, which sensitizes the tumor to RANKL and significantly enhances cancer IL-6 release. Disruption in vivo of this auto-amplifying crosstalk by knockdown of IL-6 or RANK in cancer cells, or via treatment with anti-IL-6 receptor antibodies, significantly reduces tumor growth in bone but not in soft tissues. RANKL and IL-6 mediate direct paracrine-autocrine signaling between cells of the osteoblast lineage and cancer cells, significantly enhancing the growth of metastatic breast cancers within bone.
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Study on biopharmaceutics classification and oral bioavailability of a novel multikinase inhibitor NCE for cancer therapy.
Int J Mol Sci
PUBLISHED: 02-25-2014
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Specific biopharmaceutics classification investigation and study on phamacokinetic profile of a novel drug candidate (2-methylcarbamoyl-4-{4-[3- (trifluoromethyl) benzamido] phenoxy} pyridinium 4-methylbenzenesulfonate monohydrate, NCE) were carried out. Equilibrium solubility and intrinsic dissolution rate (IDR) of NCE were estimated in different phosphate buffers. Effective intestinal permeability (P(eff)) of NCE was determined using single-pass intestinal perfusion technique in rat duodenum, jejunum and ileum at three concentrations. Theophylline (high permeability) and ranitidine (low permeability) were also applied to access the permeability of NCE as reference compounds. The bioavailability after intragastrical and intravenous administration was measured in beagle dogs. The solubility of NCE in tested phosphate buffers was quite low with the maximum solubility of 81.73 ?g/mL at pH 1.0. The intrinsic dissolution ratio of NCE was 1 × 10?? mg·min?¹·cm?². The P(eff) value of NCE in all intestinal segments was more proximate to the high-permeability reference theophylline. Therefore, NCE was classified as class II drug according to Biopharmaceutics Classification System due to its low solubility and high intestinal permeability. In addition, concentration-dependent permeability was not observed in all the segments, indicating that there might be passive transportation for NCE. The absolute oral bioavailability of NCE in beagle dogs was 26.75%. Therefore, dissolution promotion will be crucial for oral formulation development and intravenous administration route will also be suggested for further NCE formulation development. All the data would provide a reference for biopharmaceutics classification research of other novel drug candidates.
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Structural basis for Klf4 recognition of methylated DNA.
Nucleic Acids Res.
PUBLISHED: 02-11-2014
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Transcription factor Krüppel-like factor 4 (Klf4), one of the factors directing cellular reprogramming, recognizes the CpG dinucleotide (whether methylated or unmodified) within a specific G/C-rich sequence. The binding affinity of the mouse Klf4 DNA-binding domain for methylated DNA is only slightly stronger than that for an unmodified oligonucleotide. The structure of the C-terminal three Krüppel-like zinc fingers (ZnFs) of mouse Klf4, in complex with fully methylated DNA, was determined at 1.85 Å resolution. An arginine and a glutamate interact with the methyl group. By comparison with two other recently characterized structures of ZnF protein complexes with methylated DNA, we propose a common principle of recognition of methylated CpG by C2H2 ZnF proteins, which involves a spatially conserved Arg-Glu pair.
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Vitamin D Prevents the Intestinal Fibrosis Via Induction of Vitamin D Receptor and Inhibition of Transforming Growth Factor-Beta1/Smad3 Pathway.
Dig. Dis. Sci.
PUBLISHED: 02-09-2014
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Vitamin D deficiency in patients with inflammatory bowel disease (IBD) is associated with greater disease activity and lower quality of life. Intestinal fibrosis is a main complication of IBD. However, the effect of vitamin D on intestinal fibrosis remains unclear. We investigated the prophylactic effect and the underlying mechanism of vitamin D on the intestinal fibrosis in vitamin D-deficient mice with chronic colitis.
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p53 suppresses stress-induced cellular senescence via regulation of autophagy under the deprivation of serum.
Mol Med Rep
PUBLISHED: 02-07-2014
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The tumor suppressor p53 is widely known for its ability to induce cell cycle arrest or cell death, therefore preventing neoplastic progression. Previous studies have demonstrated novel roles for p53 in the regulation of autophagy and senescence. p53 can not only exert cell cycle?arresting and senescence?promoting or suppressing functions, but can also induce autophagic ?ux, particularly under conditions of nutrient deprivation. The present study demonstrated that p53 was capable of activating autophagy, which permits cell survival under conditions of serum starvation, and suppresses cellular senescence through inhibition of the mammalian target of rapamycin pathway. These results suggest that active autophagy may be a potential mechanism by which p53 suppresses cellular senescence, in response to serum starvation. The findings of the present study provide a potential mechanism for suppression of senescence by p53.
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A multi-center study of using carbon nanoparticles to track lymph node metastasis in T1-2 colorectal cancer.
Surg Endosc
PUBLISHED: 02-07-2014
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How to identify whether T1-2 colorectal cancers have lymph nodes metastases pre-op or intra-op is a crucial problem in clinic. The purpose of this study was to evaluate the feasibility of using carbon nanoparticles to track lymph nodes metastases in T1-2 colorectal cancers.
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Structure and mutagenesis of the DNA modification-dependent restriction endonuclease AspBHI.
Sci Rep
PUBLISHED: 01-28-2014
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The modification-dependent restriction endonuclease AspBHI recognizes 5-methylcytosine (5mC) in the double-strand DNA sequence context of (C/T)(C/G)(5mC)N(C/G) (N = any nucleotide) and cleaves the two strands a fixed distance (N12/N16) 3' to the modified cytosine. We determined the crystal structure of the homo-tetrameric AspBHI. Each subunit of the protein comprises two domains: an N-terminal DNA-recognition domain and a C-terminal DNA cleavage domain. The N-terminal domain is structurally similar to the eukaryotic SET and RING-associated (SRA) domain, which is known to bind to a hemi-methylated CpG dinucleotide. The C-terminal domain is structurally similar to classic Type II restriction enzymes and contains the endonuclease catalytic-site motif of DX20EAK. To understand how specific amino acids affect AspBHI recognition preference, we generated a homology model of the AspBHI-DNA complex, and probed the importance of individual amino acids by mutagenesis. Ser41 and Arg42 are predicted to be located in the DNA minor groove 5' to the modified cytosine. Substitution of Ser41 with alanine (S41A) and cysteine (S41C) resulted in mutants with altered cleavage activity. All 19 Arg42 variants resulted in loss of endonuclease activity.
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JNK confers 5-fluorouracil resistance in p53-deficient and mutant p53-expressing colon cancer cells by inducing survival autophagy.
Sci Rep
PUBLISHED: 01-24-2014
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Deficiency or mutation in the p53 tumor suppressor gene commonly occurs in human cancer and can contribute to disease progression and chemotherapy resistance. Currently, although the pro-survival or pro-death effect of autophagy remains a controversial issue, increasing data seem to support the idea that autophagy facilitates cancer cell resistance to chemotherapy treatment. Here we report that 5-FU treatment causes aberrant autophagosome accumulation in HCT116 p53(-/-) and HT-29 cancer cells. Specific inhibition of autophagy by 3-MA, CQ or small interfering RNA treatment targeting Atg5 or Beclin 1 can potentiate the re-sensitization of these resistant cancer cells to 5-FU. In further analysis, we show that JNK activation and phosphorylation of Bcl-2 are key determinants in 5-FU-induced autophagy. Inhibition of JNK by the compound SP600125 or JNK siRNA suppressed autophagy and phosphorylation of c-Jun and Bcl-2 but increased 5-FU-induced apoptosis in both HCT116 p53(-/-) and HT29 cells. Taken together, our results suggest that JNK activation confers 5-FU resistance in HCT116 p53(-/-) and HT29 cells by promoting autophagy as a pro-survival effect, likely via inducing Bcl-2 phosphorylation. These results provide a promising strategy to improve the efficacy of 5-FU-based chemotherapy for colorectal cancer patients harboring a p53 gene mutation.
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Renal events among women treated with tenofovir/emtricitabine in combination with either lopinavir/ritonavir or nevirapine.
AIDS
PUBLISHED: 01-22-2014
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Tenofovir disoproxil fumarate (TDF) has been associated with renal insufficiency. Co-administration with boosted protease inhibitors, which increases its exposure, may further increase the risk of renal insufficiency.
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Structure of a Naegleria Tet-like dioxygenase in complex with 5-methylcytosine DNA.
Nature
PUBLISHED: 01-07-2014
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Cytosine residues in mammalian DNA occur in five forms: cytosine (C), 5-methylcytosine (5mC), 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC). The ten-eleven translocation (Tet) dioxygenases convert 5mC to 5hmC, 5fC and 5caC in three consecutive, Fe(II)- and ?-ketoglutarate-dependent oxidation reactions. The Tet family of dioxygenases is widely distributed across the tree of life, including in the heterolobosean amoeboflagellate Naegleria gruberi. The genome of Naegleria encodes homologues of mammalian DNA methyltransferase and Tet proteins. Here we study biochemically and structurally one of the Naegleria Tet-like proteins (NgTet1), which shares significant sequence conservation (approximately 14% identity or 39% similarity) with mammalian Tet1. Like mammalian Tet proteins, NgTet1 acts on 5mC and generates 5hmC, 5fC and 5caC. The crystal structure of NgTet1 in complex with DNA containing a 5mCpG site revealed that NgTet1 uses a base-flipping mechanism to access 5mC. The DNA is contacted from the minor groove and bent towards the major groove. The flipped 5mC is positioned in the active-site pocket with planar stacking contacts, Watson-Crick polar hydrogen bonds and van der Waals interactions specific for 5mC. The sequence conservation between NgTet1 and mammalian Tet1, including residues involved in structural integrity and functional significance, suggests structural conservation across phyla.
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A non-intrusive method for monitoring the degradation of MOSFETs.
Sensors (Basel)
PUBLISHED: 01-04-2014
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Highly reliable embedded systems have been widely applied in the fields of aerospace, nuclear power, high-speed rail, etc., which are related to security and economic development. The reliability of the power supply directly influences the security of the embedded system, and has been the research focus of numerous electronic information and energy studies. The degradation of power modules occupies a dominant position among the key factors affecting the power supply reliability. How to dynamically determine the degradation state and forecast the remaining useful life of working power modules is critical. Therefore, an online non-intrusive method of obtaining the degradation state of MOSFETs based on the Volterra series is proposed. It uses the self-driving signal of MOSFETs as a non-intrusive incentive, and extracts the degradation characteristics of MOSFETs by the frequency-domain kernel of the Volterra series. Experimental results show that the identification achieved by the method agrees well with the theoretical analysis.
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Waist-to-Hip Ratio, Dyslipidemia, Glycemic Levels, Blood Pressure and Depressive Symptoms among Diabetic and Non-Diabetic Chinese Women: A Cross-Sectional Study.
PLoS ONE
PUBLISHED: 01-01-2014
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To explore the relationship between depressive symptoms and waist-to-hip ratio, dyslipidemia, glycemic levels or blood pressure among diabetic and non-diabetic Chinese women.
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Inhibitory role of prohibitin in human ovarian epithelial cancer.
Int J Clin Exp Pathol
PUBLISHED: 01-01-2014
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To characterize the exact individual roles of gonadotropins on ovarian epithelial carcinogenesis, an earlier study showed that prohibitin was significantly up-regulated by luteinizing hormone (LH). To further clarify the role of prohibitin in ovarian carcinogenesis and its association with LH, herein we studied the expression of prohibitin in various ovarian tissues including different developmental stages of ovarian epithelial tumors.
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Identification of glyceraldehyde 3-phosphate dehydrogenase sequence and expression profiles in tree shrew (Tupaia belangeri).
PLoS ONE
PUBLISHED: 01-01-2014
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The tree shrews (Tupaia belangeri) diverged from the primate order (Primates) and are classified as Scandentia, a separate taxonomic group of mammals. The tree shrew has been suggested to use an animal model to study human disease but the genomic sequences of tree shrew is largely unidentified. Here we identified the full-length cDNA sequence of a housekeeping gene, Glyceraldehyde 3-phosphate Dehydrogenase (GAPDH), in tree shrew. We further constructed a phylogenetic family tree base on GAPDH molecules of various organisms and compared GAPDH sequences with human and other small experimental animals. These study revealed that tree shrew was closer to human than mouse, rat, rabbit and guinea pig. The Quantitative Reverse Transcription PCR and western blot analysis further demonstrated that GAPDH expressed in various tissues in tree shrew as a general conservative housekeeping proteins as in human. Our findings provide the novel genetic knowledge of the tree shrew and strong evidences that tree shrew can be an experimental model system to study human disorders.
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Use of metformin alone is not associated with survival outcomes of colorectal cancer cell but AMPK activator AICAR sensitizes anticancer effect of 5-fluorouracil through AMPK activation.
PLoS ONE
PUBLISHED: 01-01-2014
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Colorectal cancer (CRC) is still the third most common cancer and the second most common causes of cancer-related death around the world. Metformin, a biguanide, which is widely used for treating diabetes mellitus, has recently been shown to have a suppressive effect on CRC risk and mortality, but not all laboratory studies suggest that metformin has antineoplastic activity. Here, we investigated the effect of metformin and AMPK activator AICAR on CRC cells proliferation. As a result, metformin did not inhibit cell proliferation or induce apoptosis for CRC cell lines in vitro and in vivo. Different from metformin, AICAR emerged antitumor activity and sensitized anticancer effect of 5-FU on CRC cells in vitro and in vivo. In further analysis, we show that AMPK activation may be a key molecular mechanism for the additive effect of AICAR. Taken together, our results suggest that metformin has not antineoplastic activity for CRC cells as a single agent but AMPK activator AICAR can induce apoptosis and enhance the cytotoxic effect of 5-FU through AMPK activation.
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Synthesis, characterization, and evaluation of a novel amphiphilic polymer RGD-PEG-Chol for target drug delivery system.
ScientificWorldJournal
PUBLISHED: 01-01-2014
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An amphiphilic polymer RGD-PEG-Chol which can be produced in large scale at a very low cost has been synthesized successfully. The synthesized intermediates and final products were characterized and confirmed by ¹H nuclear magnetic resonance spectrum (¹H NMR) and Fourier transform infrared spectrum (FT-IR). The paclitaxel- (PTX-) loaded liposomes based on RGD-PEG-Chol were then prepared by film formation method. The liposomes had a size within 100?nm and significantly enhanced the cytotoxicity of paclitaxel to B16F10 cell as demonstrated by MTT test (IC?? = 0.079? ?g/mL of RGD-modified PTX-loaded liposomes compared to 9.57? ?g/mL of free PTX). Flow cytometry analysis revealed that the cellular uptake of coumarin encapsulated in the RGD-PEG-Chol modified liposome was increased for HUVEC cells. This work provides a reasonable, facile, and economic approach to prepare peptide-modified liposome materials with controllable performances and the obtained linear RGD-modified PTX-loaded liposomes might be attractive as a drug delivery system.
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Surgical treatment for endometrioma does not increase clinical pregnancy rate or live birth/ongoing pregnancy rate after fresh IVF/ICSI treatment.
Am J Transl Res
PUBLISHED: 01-01-2014
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The impact of surgical treatment for endometrioma prior to assisted reproductive treatment (ART) on pregnancy outcomes remains controversy. The aim of this study is to investigate whether surgery provides benefits in subsequent ART outcomes. We retrospectively analyzed the data of 292 patients who underwent their first attempted IVF/ICSI treatment at fertility center in a university hospital, from 2011 to 2013. The primary outcomes included clinical pregnancy rate (CPR), live birth/ongoing pregnancy rate (LB/OPR). Although patients with no history of surgery and with visual endometriomas during IVF/ICSI treatment had fewer antral follicles (9.3±4.9 vs. 11.0±5.3, P=0.046), and required higher dosage of gonadotropin (3122.8±1118.1 vs. 2741.7±1096.0, P=0.043) when compared to patients who underwent surgery for endometriomas and without visual endometriomas during IVF/ICSI, the CPR and LB/OPR was not significantly affected (OR=0.771, 95%CI=0.398-1.495, and OR=1.043, 95%CI=0.526-2.069, respectively). In conclusion, surgical treatment does not significantly improve pregnancy outcomes in patients who plan to take IVF/ICSI treatment.
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Giant circular polarization conversion in layer-by-layer nonchiral metamaterial.
J Opt Soc Am A Opt Image Sci Vis
PUBLISHED: 12-11-2013
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We studied numerically the transmission properties of a kind of layer-by-layer nonchiral metamaterial. Simulation results show that under certain off-normal incidence, giant circular polarization conversion occurs for both the right and left circularly polarized waves with a roughly 1 GHz operation band. Meanwhile, the copolarization transmissions are almost suppressed to zero, leading to the high purity circular polarization transformation. This phenomenon of giant circular polarization conversion is assumed to suffer from the strong magnetic response, which is illustrated by the surface current distributions of the structure. Compared with chiral structures, this nonchiral structure is easier to design and fabricate and is expected to be used as a promising circular polarization transformer.
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Transmission resonances in a metal film with arrays of asymmetry cross-shaped apertures.
J Opt Soc Am A Opt Image Sci Vis
PUBLISHED: 12-11-2013
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We studied numerically the transmission properties of the periodic array of asymmetric cross-shaped apertures in an Ag film. The relative positions of the two orthogonally oriented rectangular apertures are varied, rather than their length or width. Each transmission peak of the original symmetric cross-shaped apertures will split into two peaks in the case of the asymmetric cross-shaped apertures when the electric field is perpendicular to the long axis of the unchanged rectangular aperture. The wavelength of the shift peak has a linear relation with the asymmetry. This resonance response mainly results from the excitation of the trapped mode provided by the structural symmetry breaking. A distribution of the magnetic field and a simple Lagrange model are used to interpret these phenomena. In addition, the intensity of the transmission peaks can be tuned by changing the incident polarization angle.
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Hormonal replacement treatment improves clinical pregnancy in frozen-thawed embryos transfer cycles: a retrospective cohort study.
Am J Transl Res
PUBLISHED: 11-15-2013
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This study aimed to assess frozen-thawed embryo transfer (FET) outcomes in natural, hormone replacement treatment (HRT) and semi-HRT cycles. This was a retrospective cohort study of 5414 cycles of patients in an academic hospital. Patients were grouped as 2216 natural cycles, 1180 semi-HRT cycles, and 2018 HRT cycles. Primary outcome measures were implantation rate, clinical pregnancy rate and live birth rate. Other parameters, such as peak endometria-thickness, were also analyzed. Patients undergoing FET with HRT obtained higher implantation rate and clinical pregnancy rate than patients with natural or semi-HR cycles (29.3% vs. 21.5% vs. 25.6%, P=0.01, and 48.7% vs. 42.7% vs. 36.1%, P=0.01, respectively). This finding was not changed in patients with thin endometrium (?8 mm). A Subanalysis in patients with HRT showed that the implantation and clinical pregnancy rate was higher in patients without ovulation than ovulatory patients (29.8% vs. 16.9%, P<0.01, and 49.5% vs. 26.3%, P<0.01, respectively). This study suggests that HRT increases the possibility of pregnancy. Further, our data showed that ovulation in HRT cycle has a detrimental effect on pregnancy. Therefore, we recommend that HRT should be used in FET cycles, and ovulation of patients should be evaluated during the treatment.
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Structural-acoustic coupling effects on the non-vacuum packaging vibratory cylinder gyroscope.
Sensors (Basel)
PUBLISHED: 11-06-2013
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The resonant shells of vibratory cylinder gyroscopes are commonly packaged in metallic caps. In order to lower the production cost, a portion of vibratory cylinder gyroscopes do not employ vacuum packaging. However, under non-vacuum packaging conditions there can be internal acoustic noise leading to considerable acoustic pressure which is exerted on the resonant shell. Based on the theory of the structural-acoustic coupling, the dynamical behavior of the resonant shell under acoustic pressure is presented in this paper. A finite element (FE) model is introduced to quantitatively analyze the effect of the structural-acoustic coupling. Several main factors, such as sealing cap sizes and degree of vacuum which directly affect the vibration of the resonant shell, are studied. The results indicate that the vibration amplitude and the operating frequency of the resonant shell will be changed when the effect of structural-acoustic coupling is taken into account. In addition, an experiment was set up to study the effect of structural-acoustic coupling on the sensitivity of the gyroscope. A 32.4 mV/°/s increase of the scale factor and a 6.2 Hz variation of the operating frequency were observed when the radial gap size between the resonant shell and the sealing cap was changed from 0.5 mm to 20 mm.
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Probing the Neural Basis of Superstition.
Brain Topogr
PUBLISHED: 09-28-2013
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Despite much evidence questioning its validity, superstitious belief continues to be rooted in the human mind. We used functional MRI to directly compare participants neural responses to monetary attractiveness with their responses to the value of an auspicious date. We found that the right middle/superior frontal gyrus showed greater deactivation whenever an auspicious-based choice was made and that the contrast between the auspicious-based and economics-based choices was negatively correlated with the participants rated wedding date-related superstitious belief, suggesting that a specific brain region carries decision signals which contribute to making decisions based on superstition and may be able to account for individual differences in superstitious behavior. The present investigation helps to reveal how the brain handles superstition.
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[Effects of intrauterine cigarette smoking exposure on expression of 3-mercaptopyruvate sulfurtransferase in medulla oblongata of neonatal rats].
Sichuan Da Xue Xue Bao Yi Xue Ban
PUBLISHED: 09-25-2013
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To investigate the expression of 3-mercaptopyruvate sulfurtransferase (3MST) in medulla oblongata of neonatal rats and effects of intrauterine cigarette exposure on its expression.
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Controlled homopolymerization of multi-vinyl monomers: dendritic polymers synthesized via an optimized ATRA reaction.
Chem. Commun. (Camb.)
PUBLISHED: 09-18-2013
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In this study, we have managed to find the optimal ATRA system that can obtain the highest mono-adduct yields with the purpose of minimizing the chain growth of divinyl monomers. The most highly hyperbranched polymers have been synthesized by the homopolymerization of multi-vinyl monomers via ATRA reaction.
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Mussel-inspired hyperbranched poly(amino ester) polymer as strong wet tissue adhesive.
Biomaterials
PUBLISHED: 09-03-2013
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Current medical adhesives based on cyanoacrylates typically exhibit cellular toxicity. In contrast, fibrin adhesives are non-toxic but have poor adhesive properties. To overcome these drawbacks we designed a simple and scalable adhesive precursor inspired by marine mussel adhesion that functioned with strong adhesion in wet conditions and with low cytotoxicity. Dopamine, an-amine derivative of an amino acid abundantly present in mussel adhesive proteins, was co-polymerised with a tri-functional vinyl monomer, to form a hyperbranched poly(?-amino ester) polymer termed poly(dopamine-co-acrylate) (PDA). A variety of molecular weights and crosslinking methods were analysed using an ex vivo porcine skin model and an almost 4 fold increase in wet adhesion strength was observed compared to TISSEEL(®) fibrin sealant. With a fast curing time, degradable properties and low cytotoxicity, PDA is highly attractive for medical purposes and could have a broad impact on surgeries where surgical tissue adhesives, sealants, and haemostatic agents are used.
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Solution structure and dynamics of human hemoglobin in the carbonmonoxy form.
Biochemistry
PUBLISHED: 08-15-2013
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The solution structure of human adult carbonmonoxy hemoglobin (HbCO A) was refined using stereospecifically assigned methyl groups and residual dipolar couplings based on our previous nuclear magnetic resonance structure. The tertiary structures of individual chains were found to be very similar to the X-ray structures, while the quaternary structures in solution at low salt concentrations resembled the X-ray R structure more than the R2 structure. On the basis of chemical shift perturbation by inositol hexaphosphate (IHP) titration and docking, we identified five possible IHP binding sites in HbCO A. Amide-water proton exchange experiments demonstrated that ?Thr38 located in the ?1?2 interface and several loop regions in both ?- and ?-chains were dynamic on the subsecond time scale. Side chain methyl dynamics revealed that methyl groups in the ?1?2 interface were dynamic, but those in the ?1?1 interface were quite rigid on the nanosecond to picosecond and millisecond to microsecond time scales. All the data strongly suggest a dynamic ?1?2 interface that allows conformational changes among different forms (like T, R, and R2) easily in solution. Binding of IHP to HbCO A induced small structural and dynamic changes in the ?1?2 interface and the regions around the hemes but did not increase the conformational entropy of HbCO A. The binding also caused conformational changes on the millisecond time scale, very likely arising from the relative motion of the ?1?1 dimer with respect to the ?2?2 dimer. Heterotropic effectors like IHP may change the oxygen affinity of Hb through modulating the relative motion of the two dimers and then further altering the structure of heme binding regions.
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Depolymerization and decolorization of kraft lignin by bacterium Comamonas sp. B-9.
Appl. Microbiol. Biotechnol.
PUBLISHED: 07-31-2013
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There is no commercial or industrial-scale process for the remediation of black liquor using microorganisms to date. One of the most important causes is that most microorganisms are not able to use lignin as their principal metabolic carbon or energy source. The bacterial strain Comamonas sp. B-9 has shown remarkable ability to degrade kraft lignin and decolorize black liquor using lignin as its principal metabolic carbon and energy source. This report looks at the depolymerization and decolorization of kraft lignin by Comamonas sp. B-9. The degradation, decolorization, and total carbon removal reached 45, 54, and 47.3 %, respectively, after 7 days treatment. Comamonas sp. B-9 was capable of depolymerizing kraft lignin effectively as analyzed by gel permeation chromatography and decolorization via degrading benzene ring structures as shown using Fourier transform infrared spectroscopy analysis.
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Key regions of the cerebral network are altered after electroacupuncture at the Baihui (GV20) and Yintang acupuncture points in healthy volunteers: an analysis based on resting fcMRI.
Acupunct Med
PUBLISHED: 07-25-2013
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To identify the key cerebral functional region affected by acupuncture point needling by examining cerebral networks using functional connectivity MRI (fcMRI) and analysing changes in the key regions of these brain networks at different time points after needle removal.
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PTK6 activation at the membrane regulates epithelial-mesenchymal transition in prostate cancer.
Cancer Res.
PUBLISHED: 07-15-2013
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The intracellular tyrosine kinase protein tyrosine kinase 6 (PTK6) lacks a membrane-targeting SH4 domain and localizes to the nuclei of normal prostate epithelial cells. However, PTK6 translocates from the nucleus to the cytoplasm in human prostate tumor cells. Here, we show that while PTK6 is located primarily within the cytoplasm, the pool of active PTK6 in prostate cancer cells localizes to membranes. Ectopic expression of membrane-targeted active PTK6 promoted epithelial-mesenchymal transition in part by enhancing activation of AKT, thereby stimulating cancer cell migration and metastases in xenograft models of prostate cancer. Conversely, siRNA-mediated silencing of endogenous PTK6 promoted an epithelial phenotype and impaired tumor xenograft growth. In mice, PTEN deficiency caused endogenous active PTK6 to localize at membranes in association with decreased E-cadherin expression. Active PTK6 was detected at membranes in some high-grade human prostate tumors, and PTK6 and E-cadherin expression levels were inversely correlated in human prostate cancers. In addition, high levels of PTK6 expression predicted poor prognosis in patients with prostate cancer. Our findings reveal novel functions for PTK6 in the pathophysiology of prostate cancer, and they define this kinase as a candidate therapeutic target. Cancer Res; 73(17); 5426-37. ©2013 AACR.
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Exploring microbial succession and diversity during solid-state fermentation of Tianjin duliu mature vinegar.
Bioresour. Technol.
PUBLISHED: 07-05-2013
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Tianjin duliu mature vinegar was one of famous Chinese traditional vinegars. The unique flavor and taste of vinegar are mainly generated by the multitudinous microorganisms during fermentation. In this research, the composition and succession of microbial communities in the entire solid-state fermentation were investigated, including starter daqu and acetic acid fermentation (AAF). Molds and yeasts in daqu, including Aspergillus, Saccharomycopsis and Pichia, decreased in AAF. The bacterial compositions increased from four genera in daqu to more than 13 genera in AAF. Principal component analysis showed that Acetobacter, Gluconacetobacter, Lactobacillus and Nostoc were dominant bacteria that were correlated well with AAF process. In the early fermentation period, lactic acid bacteria (LAB) decreased while acetic acid bacteria and Nostoc increased rapidly with the accumulation of total acids. Then, the abundance and diversity of LAB increased (more than 80%), indicating that LAB had important influences on the flavor and taste of vinegar.
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Gene delivery with active targeting to ovarian cancer cells mediated by folate receptor alpha.
J Biomed Nanotechnol
PUBLISHED: 06-28-2013
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Folate receptor alpha (FRalpha) is overexpressed on ovarian cancer cells and is a promising molecular target for ovarian cancer gene therapy, but there was still no related report. In this study, folate modified cationic liposomes (F-PEG-CLPs) for ovarian cancer gene delivery were developed for the first time. Folate-poly(ethylene glycol)-succinate-cholesterol (F-PEG-suc-Chol) was firstly synthesized and then used to prepare folate-targeted cationic liposomes/plasmid DNA complexes (F-targeted lipoplexes). F-targeted lipoplexes were prepared by post-insertion method, and displayed membrane structure by transmission electron microscopy observation with the diameter of 193 nm-200 nm and the zeta potential of 35 mV-38 mV. DNase degradation experiments showed that plasmid DNA could be effectively shielded by F-targeted lipoplexes in vitro. F-targeted lipoplexes could transfer gene into human ovarian carcinoma cell line SKOV-3, and 0.1% F-PEG-CLPs composed by DOTAP/Chol/mPEG-Chol/F-PEG-suc-Chol (50:45:5:0.1, molar ratio) had the highest transfection efficiency. The transfection activity of F-targeted lipoplexes could be competitively inhibited by free folic acid, demonstrating that folate-FRalpha interaction caused high transfection efficiency of F-targeted lipoplexes. The uptake mechanism of F-targeted lipoplexes was further validated on human oral carcinoma cell line KB and human liver carcinoma cell line HepG2. The concentration-dependent and time-dependent cytotoxicity of targeted material F-PEG-suc-Chol was observed by MTT assay on SKOV-3 cell and its application would not increase the cytotoxicity of F-targeted lipoplexes in SKOV-3 cells. All the data indicated that F-PEG-CLPs would be a promising gene vector targeting for ovarian cancer therapy.
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Uric Acid Levels in Obstructive Sleep Apnea Patients with Atrial Fibrillation.
Arch. Med. Res.
PUBLISHED: 06-27-2013
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The objective of this observational study was to determine whether there is an association between atrial fibrillation (AF) and uric acid and to identify the risk markers for AF in obstructive sleep apnea (OSA).
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Resistin impairs SIRT1 function and induces senescence-associated phenotype in hepatocytes.
Mol. Cell. Endocrinol.
PUBLISHED: 06-18-2013
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Resistin is a cysteine-rich secreted protein which significantly inhibits phosphorylation of AMP-activated protein kinase in both human and mouse hepatocytes. It has been demonstrated that resistin plays an important role in inducing hepatic insulin resistance. However, whether resistin has other unknown influences on hepatocytes still remains poorly studied. Here, we show that recombinant resistin protein significantly reduces expression of SIRT1, attenuates the interaction between SIRT1 and PPAR? as well as PGC-1?, and increases PGC-1? acetyl-lysine levels in HepG2 cells. In line with this, resistin treatment weakens the association between SIRT1 and major satellite repeats and alters the transcription level of SIRT1 target genes in mouse primary hepatocytes. Resistin treatment also significantly increases senescence-associated ?-galactosidase activity in mouse primary hepatocytes and this effect can be eliminated by co-treatment with the SIRT1 agonists resveratrol and nicotinamide mononucleotide. Our findings suggest that resistin is a negative regulator of SIRT1 in both human hepatoma cell line HepG2 and mouse hepatocytes and that it might also play an important role in the development of senescence-associated liver diseases.
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Chronic intermittent hypoxia promotes expression of 3-mercaptopyruvate sulfurtransferase in adult rat medulla oblongata.
Auton Neurosci
PUBLISHED: 05-19-2013
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The present experiments were carried out to investigate the expression of 3-mercaptopyruvate sulfurtransferase (3MST) in medulla oblongata of rats and effects of chronic intermittent hypoxia (CIH) on its expression. Sprague Dawley adult rats were randomly divided into two groups, including control (Con) group and CIH group. The endogenous production of hydrogen sulfide (H2S) in medulla oblongata tissue homogenates was measured using the methylene blue assay method, 3MST mRNA and protein expression were analyzed by RT-PCR and Western blotting, respectively, and the expression of 3MST in the neurons of respiratory-related nuclei in medulla oblongata of rats was investigated with immunohistochemical technique. CIH elevated the endogenous H2S production in rat medulla oblongata (P<0.01). The RT-PCR and Western blotting analyses showed that 3MST mRNA and protein were expressed in the medulla oblongata of rats and CIH promoted their expression (P<0.01). Immunohistochemical staining indicated that 3MST existed in the neurons of pre-Bötzinger complex (pre-BötC), hypoglossal nucleus (12N), ambiguous nucleus (Amb), facial nucleus (FN) and nucleus tractus solitarius (NTS) in the animals and the mean optical densities of 3MST-positive neurons in the pre-BötC, 12N and Amb, but not in FN and NTS, were significantly increased in CIH group (P<0.05). In conclusion, 3MST exists in the neurons of medullary respiratory nuclei and its expression can be up-regulated by CIH in adult rat, suggesting that 3MST-H2S pathway may be involved in regulation of respiration and protection on medullary respiratory centers from injury induced by CIH.
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[Preparation and in vitro evaluation of pDNA-CaPi-PLGA nanoparticles with a core-shell structure].
Yao Xue Xue Bao
PUBLISHED: 05-16-2013
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To develop a core-shell structure pDNA-CaPi-PLGA nanoparticles (CS-pDNA-CaPi-PLGA-NPs), calcium phosphate-pDNA nano complexes (CaPi-pDNA) were encapsulated inside of PLGA shells. The characteristics of the nanoparticles, including morphology, average particle size, zeta potential, entrapment efficiency, loading efficiency, stability in medium, pDNA protection ability from nuclease degradation, in vitro release, cytotoxicity and cell transfection were investigated and compared with the embedded structured CaPi modified PLGA nanoparticles (embedded-pDNA-CaPi-PLGA-NPs). The results showed that the obtained CS-pDNA-CaPi-PLGA-NPs were spherical in shape with an average particle size of (155 +/- 4.5) nm, zeta potentials of (-0.38 +/- 0.1) mV, entrapment efficiency of (80.56 +/- 2.5)% and loading efficiency of (1.16 +/- 0.04)%. The CS-pDNA-CaPi-PLGA-NPs were stable in the release media and could protect pDNA against nuclease degradation. And they also exhibited sustained release of pDNA in vitro. The highest gene transfection efficiency of the CS-pDNA-CaPi-PLGA-NPs in vitro reached (24.66 +/- 0.46)% (after 72 h transfection), which was significantly higher than that of free pDNA [(0.33 +/- 0.04)%, P < 0.01] and the pDNA-PLGA-NPs [(1.5 +/- 0.07)%, P < 0.01]. Besides, the transfection lasted for longer time than that of embedded-pDNA-CaPi-PLGA-NPs and the cytotoxicity of it was significantly lower than that of PEI (P < 0.01). These results indicate that CS-pDNA-CaPi-PLGA-NPs are a promising non-viral gene vector. Key words: gene delivery system; polylactic-co-glycolic acid; calcium phosphate; nanoparticle
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Evaluation of the relationship between extremity soft tissue sarcomas and adjacent major vessels using contrast-enhanced multidetector CT and three-dimensional volume-rendered CT angiography: a preliminary study.
Acta Radiol
PUBLISHED: 05-09-2013
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Accurate description of the relationship between extremity soft tissue sarcoma and the adjacent major vessels is crucial for successful surgery. In addition to magnetic resonance imaging (MRI) or in patients who cannot undergo MRI, two-dimensional (2D) postcontrast computed tomography (CT) images and three-dimensional (3D) volume-rendered CT angiography may be valuable alternative imaging techniques for preoperative evaluation of extremity sarcomas.
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Evolutionary increases in defense during a biological invasion.
Oecologia
PUBLISHED: 05-07-2013
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Invasive plants generally escape from specialist herbivores of their native ranges but may experience serious damage from generalists. As a result, invasive plants may evolve increased resistance to generalists and tolerance to damage. To test these hypotheses, we carried out a common garden experiment comparing 15 invasive populations with 13 native populations of Chromolaena odorata, including putative source populations identified with molecular methods and binary choice feeding experiments using three generalist herbivores. Plants from invasive populations of C. odorata had both higher resistance to three generalists and higher tolerance to simulated herbivory (shoot removal) than plants from native populations. The higher resistance of plants from invasive populations was associated with higher leaf C content and densities of leaf trichomes and glandular scales, and lower leaf N and water contents. Growth costs were detected for tolerance but not for resistance, and plants from invasive populations of C. odorata showed lower growth costs of tolerance. Our results suggest that invasive plants may evolve to increase both resistance to generalists and tolerance to damage in introduced ranges, especially when the defense traits have low or no fitness costs. Greater defenses in invasive populations may facilitate invasion by C. odorata by reducing generalist impacts and increasing compensatory growth after damage has occurred.
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Similar structures, different characteristics: circular dichroism of metallic helix arrays with single-, double-, and triple-helical structures.
J Opt Soc Am A Opt Image Sci Vis
PUBLISHED: 04-19-2013
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We fabricated three-dimensional metallic helix arrays with single-, double-, and triple-helical structures. The transmission performances with the normal incident angle were measured in the microwave frequency of 12-18 GHz. For the single- and double-helical structures, giant circular dichroism with fairly wide bands is observed in the transmission spectra. However, the triple-helical structure does not exhibit circular dichroism. Based on the phenomenon of circular dichroism, the single- and double-helical structures can be used as broadband circular polarizers in the microwave region, but triple-helical ones cannot. The experiments have a good agreement with our simulation results, which were studied by the finite-difference time domain method.
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Environmentally safe treatment of black liquor with Comamonas sp. B-9 under high-alkaline conditions.
J. Basic Microbiol.
PUBLISHED: 04-02-2013
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The strain Comamonas sp. B-9 was isolated from steeping fluid of erosive bamboo slips derived from Kingdom Wu during the Three-Kingdoms Dynasty of ancient China (A.D. 220-280). It could be used to treat black liquor (BL) with high-alkaline pH and with an initial chemical oxygen demand (COD) of 18,000-25,000?mg?L(-1) , without the addition of other carbon and nitrogen sources. The results revealed that Comamonas sp. B-9 was capable of reducing the COD, color, and lignin content of BL by up to 56.8, 35.3, and 43.5%, respectively. High levels of laccase, manganese peroxidase, cellulase, and xylanase enzymatic activities were also observed, and these enzymes could play an important role in the biotreatment of BL. Further, GC-MS analysis showed that most of the compounds detected in BL after biotreatment with Comamonas sp. B-9 were diminished, while 4-methyl benzaldehyde, 3,4,5-trihydroxybenzoic acid ethyl ester, and 4-hydroxy-3,5-dimethoxy benzaldehyde were produced as metabolites. The presented results indicate that Comamonas sp. B-9 has potential application for the treatment of wastewaters from pulp and paper processing with high COD load under high-alkaline conditions.
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Biochemical investigation of kraft lignin degradation by Pandoraea sp. B-6 isolated from bamboo slips.
Bioprocess Biosyst Eng
PUBLISHED: 03-19-2013
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Kraft lignin (KL) is the major pollutant in black liquor. The bacterial strain Pandoraea sp. B-6 was able to degrade KL without any co-substrate under high alkaline conditions. At least 38.2 % of chemical oxygen demand and 41.6 % of color were removed in 7 days at concentrations from 1 to 6 g L(-1). The optimum pH for KL degradation was 10 and the optimum temperature was 30 °C. The greatest activities of 2,249.2 U L(-1) for manganese peroxidase and 1,120.6 U L(-1) for laccase were detected on the third and fifth day at pH 10, respectively. Many small molecules, such as cinnamic acid, ferulic acid, 2-hydroxy benzyl alcohol, and vanillyl methyl ketone, were formed during the period of KL degradation based on GC-MS analysis. These results indicate that this strain has great potential for biotreatment of black liquor.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.