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Find video protocols related to scientific articles indexed in Pubmed.
Asymmetric Hetero-Diels-Alder Reaction of Diazenes Catalyzed by Chiral Silver Phosphate: Water Participates in the Catalysis and Stereocontrol.
Org. Lett.
PUBLISHED: 11-20-2014
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The chiral silver phosphate was confirmed to efficiently catalyze a highly regio- and enantioselective hetero-Diels-Alder reaction of diazenes to furnish piperazine derivatives in high yields and excellent ee values. DFT calculations revealed that the water molecule participates in the catalysis by coordination to silver phosphate and also found that the hydroxy group of 1-hydroxy-2,3-hexadiene not only formed a hydrogen bond with the oxygen of phosphate but also coordinated to the Ag(I) to simultaneously stabilize the transition states and control the regioselectivity.
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A netlike rolling circle nucleic acid amplification technique.
Analyst
PUBLISHED: 11-20-2014
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A nucleic acid amplification technique termed as netlike rolling circle amplification is proposed by introducing a nicking enzyme into the existing hyperbranched rolling circle amplification system. Surprisingly dense and uniform network morphology is observed; and cubic amplification is achieved for the sensitive detection of a sequence from HIV.
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CO2 and temperature dual responsive "Smart" MXene phases.
Chem. Commun. (Camb.)
PUBLISHED: 11-20-2014
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A robust strategy is explored to graft poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brushes on two-dimensional vanadium carbide (V2C) materials through self-initiated photografting and photopolymerization (SIPGP). CO2 and temperature dual-responsive properties of PDMAEMA allow this hybrid to be used as a smart system for tuning the transmittance and conductivity of V2C.
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Chinese Herbal Medicine for Obesity: A Randomized, Double-Blinded, Multicenter, Prospective Trial.
Am. J. Chin. Med.
PUBLISHED: 11-20-2014
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Obesity is a serious medical problem worldwide. As a holistic therapy, traditional Chinese medicine (TCM) may have a potential in obesity management. In this controlled trial, we evaluated the safety and effectiveness of Xin-Ju-Xiao-Gao-Fang (XJXGF), a TCM herbal formulation, in 140 obese subjects over a 24-week period. The XJXGF formula mainly consists of rhubarb, coptis, semen cassia, and citrus aurantium. Subjects with body mass index (BMI) 28-40 kg/m(2) were recruited at 5 centers in China. We assessed the changes in subjects' body weight, its related parameters, and the reduction of insulin resistance (IR) after administration of XJXGF formula or low-dose XJXGF (10% of the XJXGF formula, as control). After 24-week treatment, among participants in the XJXGF formula group and low-dose XJXGF group, the mean ± SE changes in the body weight were -3.58±0.48 and -1.91±0.38 kg, respectively (p < 0.01). The changes in the IR-index of two groups were -2.65±1.04 and -1.58±1.3, respectively (p < 0.05). There were no serious adverse events reported during the 24-week trial. Participants reported 7 minor adverse events, 4 in the XJXGF formula group and 3 in the low-dose XJXGF group (p = 0.578). Future studies are needed to investigate the clinical utility of this TCM formulation in the treatment of obese subjects.
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Titanium nanoparticles inhalation induces renal fibrosis in mice via an oxidative stress-up-regulated transforming growth factor-? pathway.
Chem. Res. Toxicol.
PUBLISHED: 11-19-2014
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Titanium dioxide nanoparticles (Nano-TiO2) are gradually extensively used in the clinical, industry and daily life. Accumulation studies showed that Nano-TiO2 exposure is able to cause injuries in various animal organs, including lung, liver, spleen, and kidney. However, it remains unclear whether exposure of Nano-TiO2 by inhalation causes renal fibrosis. Here, we investigated the role of reactive oxygen species (ROS)/reactive nitrogen species (RNS)-related signalling molecules in the chronic renal damage after Nano-TiO2 inhalation in mice. Mice were treated with Nano-TiO2 (0.1, 0.25, and 0.5 mg/week) or microparticle-TiO2 (0.5 mg/week) by non-surgical intratracheal instillation for 4 weeks. The results showed that Nano-TiO2 inhalation increased renal pathological changes in a dose-dependent manner. No renal pathological changes were observed in microparticle-TiO2-instilled mice. Nano-TiO2 (0.5 mg/week) possessed the ability to precipitate in the kidneys determined by transmission electron microscopy and increased serum levels of blood urea nitrogen. The expressions of markers of ROS/RNS and renal fibrosis markers, including nitrotyrosine, inducible nitric oxide synthase, hypoxia inducible factor-1? (HIF-1?), heme oxygenase 1, transforming growth factor-? (TGF?), and collagen I determined by immunohistochemical staining were increased in the kidneys. Furthermore, Nano-TiO2-induced renal injury could be mitigated by iNOS inhibitor aminoguanidine and ROS scavenger N-acetylcysteine treatment in transcription level. The in vitro experiments showed that Nano-TiO2 significantly and dose-dependently increased the ROS production and the expressions of HIF-1??and TGF? in human renal proximal tubular cells, which could be reversed by N-acetylcysteine treatment. Taken together, these results suggest Nano-TiO2 inhalation might induce the renal fibrosis through a ROS/RNS-related HIF-1?-up-regulated TGF-? signalling pathway.
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Association between Reversal in the Expression of Hyperpolarization-Activated Cyclic Nucleotide-Gated (HCN) Channel and Age-Related Atrial Fibrillation.
Med. Sci. Monit.
PUBLISHED: 11-19-2014
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Background We compared cardiac electrophysiological indicators and regional expression levels of cardiac hyperpolarization-activated cyclic nucleotide-gated (HCN) channels between adult and aged dogs to identify possible mechanisms of age-related atrial fibrillation. Material and Methods Corrected sinus node recovery time (SNRTc) and effective refractory period (ERP) of the atrium and pulmonary veins were measured in 10 adult (3-6 years old) and 10 aged dogs (>9 years old). Expression levels of HCN2 and HCN4 channel mRNAs and proteins were measured in the sinoatrial node, atrium, and pulmonary veins by real-time PCR and Western blotting. Results Aged dogs exhibited a higher induction rate of atrial fibrillation (AF) in response to electrical stimulation, longer AF duration after induction, longer SNRTc, longer right atrial effective refractory period (AERP), shorter left AERP, and increased AERP dispersion compared to adults. Expression levels of HCN2 and HCN4 channel mRNAs and proteins were lower in the sinoatrial node but higher in the atrium and pulmonary veins of aged dogs. Conclusions Changes in atrial electrophysiological indicators in aged dogs revealed sinoatrial node dysfunction. There was a reversal in the local tissue distribution of HCN2 and HCN4 channel mRNA and protein, a decrease in sinoatrial node expression, and increase in atrial and pulmonary vein expression with age. Changes in atrial electrophysiological characteristics and regional HCN channel expression patterns were associated with the onset and maintenance of age-related atrial fibrillation.
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Aptamer photoregulation in vivo.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 11-19-2014
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The in vivo application of aptamers as therapeutics could be improved by enhancing target-specific accumulation while minimizing off-target uptake. We designed a light-triggered system that permits spatiotemporal regulation of aptamer activity in vitro and in vivo. Cell binding by the aptamer was prevented by hybridizing the aptamer to a photo-labile complementary oligonucleotide. Upon irradiation at the tumor site, the aptamer was liberated, leading to prolonged intratumoral retention. The relative distribution of the aptamer to the liver and kidney was also significantly decreased, compared to that of the free aptamer.
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Templated Fabrication of Fiber-Basket Polymersomes via Crystallization-Driven Block Copolymer Self-Assembly.
J. Am. Chem. Soc.
PUBLISHED: 11-19-2014
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Immobilizing uniform nanostructures on a mesoscale substrate is a promising approach to prepare nanometer to micrometer sized materials with new functionalities. The hierarchical structures formed depend on both the nature of the substrate and the components deposited. In this paper, we describe the use of colloidal polystyrene microbeads as a sacrificial template to create a nanofibrous network coating consisting of elongated block copolymer micelles. This network has a secondary structure very different from that of conformal coatings obtained by other methods. In addition, the fibers of the network could be elongated by crystallization-driven self-assembly. The network was locked in place by cross-linking the micelles through in situ generation of small Pt nanoparticles. Subsequent removal of the sacrificial template gave an open vesicular structure. To demonstrate further transformation of the membrane, we showed that the cross-linked micelles could also be used to embed silver nanoparticles. The sacrificial template contained known amounts of Tb and Tm ions, allowing us to estimate via atomic mass spectrometry that 85% of the template surface was covered with micelle seeds. This approach to fabricating hierarchical coating structures expands the generality and scope of template-assisted synthesis to build advanced hierarchical materials with precise morphological control.
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The effect of transportation of broilers during summer on the expression of heat shock protein 70, postmortem metabolism and meat quality.
J. Anim. Sci.
PUBLISHED: 11-19-2014
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The objective of this study was to determine the effects of different transport times on broilers during summer on stress, meat quality and early postmortem muscle metabolites. Arbor Acres broiler chickens (n = 105) were randomly categorized into five treatments: unstressed control, 0.5 h, 1 h, 2 h and 4 h transport. Each treatment consisted of 3 replicates with 7 birds each. All birds (except the control group) were transported according to a designed protocol. With the extension of transport time, the activities of plasma creatine kinase (CK) and lactate dehydrogenase (LDH) gradually increased. The content of heat shock protein 70 (Hsp70) did not change significantly during 0.5 h transport compared to the control group, but was significantly higher (P < 0.05) at 1 h or more of transport time. Also, transport times of 2 h or more resulted in a death rate of 20 - 33% of broilers. We found that the breast meat in the 0.5 h transport group had significantly (P < 0.05) higher L* values, drip loss, cooking loss, AMP/ATP ratio and phosphorylation of AMP-activated protein kinase (p-AMPK). In addition, pH24h was lower compared to the control group, increasing the likelihood of pale, soft and exudative (PSE)-like meat. However, no significant variations were found in meat color, drip loss or cooking loss in other transport groups compared to the control group under the condition of this study. Muscle glycogen content decreased with time of transportation. There were significant correlations among p-AMPK and meat quality (P < 0.05). These results indicate that pre-slaughter transport during summer may cause severe physiological and biochemical changes of broilers. Further investigations studying the deeper relationship between biological indicators and meat quality according to the similar transport conditions would provide a better understanding of the effect of transport duration on meat quality.
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Glycyrrhetinic acid triggers a protective autophagy by activation of extracellular regulated protein kinases in hepatocellular carcinoma cells.
J. Agric. Food Chem.
PUBLISHED: 11-19-2014
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Glycyrrhetinic acid (GA), one of the main constituents of the famous Chinese medicinal herb and food additive licorice (Glycyrrhiza uralensis Fisch), has been indicated with potential anti-cancer effects and widely utilized in hepatocellular carcinoma (HCC) targeted drug delivery systems (TDDS) due to the highly expressed target binding sites of GA on HCC cells. Herein, we found that GA reduced the cell viability, increased the release of lactate dehydrogenase, and enhanced the expression of Bax, cleaved-caspase 3 and LC3-II in HCC cells. The GA-triggered autophagy has been further confirmed by monodansylcadaverine staining as well as transmission electron microscopy analysis. The cell viability was obviously decreased while the expression of cleaved caspases was signi?cantly increased when inhibition of autophagy by choloroquine or bafilomycin A1, suggesting that GA triggered a protective autophagy. Extracellular regulated protein kinase (ERK) was activated after treatment with GA in HepG2 cells, and pretreatment with U0126 or PD98059, the MEK inhibitors, reversed GA-triggered autophagy evidenced by decreased expression of LC3-II and formation of autophagosomes, respectively. Furthermore, GA-induced cell death and apoptosis were enhanced after pretreatment with PD98059. As far as we know, this is the first report that GA triggers a protective autophagy in HCC cells via activation of ERK, which might attenuate the anti-cancer effects of GA or chemotherapeutic drugs loaded GA-modified TDDS.
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Common-path and compact wavefront diagnosis system based on cross grating lateral shearing interferometer.
Appl Opt
PUBLISHED: 11-18-2014
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A common-path and compact wavefront diagnosis system for both continuous and transient wavefronts measurement is proposed based on cross grating lateral shearing interferometer (CGLSI). Derived from the basic CGLSI configuration, this system employs an aplanatic lens to convert the wavefront under test into a convergent beam, which makes it possible for CGLSI to test the wavefront of collimated beams. A geometrical optics model for grating pitch determination and a Fresnel diffraction model for order selection mask design are presented. Then a detailed analysis about the influence of the grating pitch, the distance from the cross grating to the order selection mask and the numerical aperture of the aplanatic lens on the system error is made, and a calibration method is proposed to eliminate the system error. In addition, the differential Zernike polynomials fitting method is introduced for wavefront retrieval. Before our experiment, we have designed several grating pitches and their corresponding order selection mask parameters. In the final comparative experiment with ZYGO interferometer, the wavefront diagnosis system exhibits both high precision and repeatability.
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[Comparison of extracorporeal membrane oxygenation and mechanical ventilation for inter-hospital transport of severe acute respiratory distress syndrome patients].
Zhonghua Wei Zhong Bing Ji Jiu Yi Xue
PUBLISHED: 11-18-2014
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To compare inter-hospital transport and clinical outcome in severe acute respiratory distress syndrome (ARDS)patients whom were transported either on extracorporeal membrane oxygenation (ECMO) or on conventional ventilation, and to investigate the optimal means of inter-hospital transport.
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Modulation of the Maladaptive Stress Response to Manage Diseases of Protein Folding.
PLoS Biol.
PUBLISHED: 11-01-2014
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Diseases of protein folding arise because of the inability of an altered peptide sequence to properly engage protein homeostasis components that direct protein folding and function. To identify global principles of misfolding disease pathology we examined the impact of the local folding environment in alpha-1-antitrypsin deficiency (AATD), Niemann-Pick type C1 disease (NPC1), Alzheimer's disease (AD), and cystic fibrosis (CF). Using distinct models, including patient-derived cell lines and primary epithelium, mouse brain tissue, and Caenorhabditis elegans, we found that chronic expression of misfolded proteins not only triggers the sustained activation of the heat shock response (HSR) pathway, but that this sustained activation is maladaptive. In diseased cells, maladaptation alters protein structure-function relationships, impacts protein folding in the cytosol, and further exacerbates the disease state. We show that down-regulation of this maladaptive stress response (MSR), through silencing of HSF1, the master regulator of the HSR, restores cellular protein folding and improves the disease phenotype. We propose that restoration of a more physiological proteostatic environment will strongly impact the management and progression of loss-of-function and gain-of-toxic-function phenotypes common in human disease.
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[Huanglian jiedu decoction regulated and controlled differentiation of monocytes, macrophages, and foam cells: an experimental study].
Zhongguo Zhong Xi Yi Jie He Za Zhi
PUBLISHED: 10-23-2014
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To observe the effect of Huanglian Jiedu Decoction (HLJDD) in in vivo regulating differentiation of monocytes in an apolipoprotein E knockout (ApoE(-/-)) mouse model, and to observe the effect of HLJDD-containing serum in in vitro regulating differentiation of macrophages and foam cells.
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A Randomized, Three-arm Study to Optimize Lamivudine Efficacy in HBeAg Positive Chronic Hepatitis B Patients.
J. Gastroenterol. Hepatol.
PUBLISHED: 10-14-2014
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To compare the efficacy at week 104 of lamivudine monotherapy (MONO), lamivudine plus adefovir dipivoxil (ADV) combination therapy (COMBO), and lamivudine optimization strategy (OPTIMIZE).
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[Colonization characteristics of endophytic bacteria NJ13 in Panax ginseng and its biocontrol efficiency against Alternaria leaf spot of ginseng].
Zhongguo Zhong Yao Za Zhi
PUBLISHED: 10-07-2014
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To reveal the colonization characteristics in host of endophytic biocontrol bacteria NJ13 isolated from Panax ginseng, this study obtained the marked strain NJ13-R which was double antibiotic resistant to rifampicin and streptomycin through enhancing the method of inducing antibiotic. The colonization characteristics in ginseng and its biocontrol efficiency against Alternaria spot of ginseng in the field were studied. The results showed that the strain could colonize in root, stem and leaf of ginseng and the colonization amount was positive correlated with inoculation concentration. Meanwhile, the strain could infect and then transfer in different tissues of ginseng The colonization amount of strain in roots and leaves of ginseng increased first and then decreased. However, the tendency of colonization amount of strain in stems was ascend at first and then descend slowly, and was more than that in roots and leaves along with time, which had a preference to specific tissue of its host. In field experiment, the endophytic bacteria NJ13 was proved to be effective in controlling Alternaria leaf spot of ginseng. The biocontrol efficiency of fermentation broth at the concentration of 0.76 x 10(8) cfu x mL(-1) reached 75.62%, which was close to the controlling level (73.06%) of 0.67 mg x L(-1) 50% cyprodinil WG.
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A new active cavitation mapping technique for pulsed HIFU applications--bubble Doppler.
IEEE Trans Ultrason Ferroelectr Freq Control
PUBLISHED: 09-30-2014
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In this work, a new active cavitation mapping technique for pulsed high-intensity focused ultrasound (pHIFU) applications termed bubble Doppler is proposed and its feasibility is tested in tissue-mimicking gel phantoms. pHIFU therapy uses short pulses, delivered at low pulse repetition frequency, to cause transient bubble activity that has been shown to enhance drug and gene delivery to tissues. The current gold standard for detecting and monitoring cavitation activity during pHIFU treatments is passive cavitation detection (PCD), which provides minimal information on the spatial distribution of the bubbles. B-mode imaging can detect hyperecho formation, but has very limited sensitivity, especially to small, transient microbubbles. The bubble Doppler method proposed here is based on a fusion of the adaptations of three Doppler techniques that had been previously developed for imaging of ultrasound contrast agents-color Doppler, pulse-inversion Doppler, and decorrelation Doppler. Doppler ensemble pulses were interleaved with therapeutic pHIFU pulses using three different pulse sequences and standard Doppler processing was applied to the received echoes. The information yielded by each of the techniques on the distribution and characteristics of pHIFU-induced cavitation bubbles was evaluated separately, and found to be complementary. The unified approach-bubble Doppler-was then proposed to both spatially map the presence of transient bubbles and to estimate their sizes and the degree of nonlinearity.
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[Screening and identification of an endophytic bacterium with 1-aminocyclopropane-1-carboxylate deaminase activity from Panax ginseng and its effect on host growth].
Wei Sheng Wu Xue Bao
PUBLISHED: 09-26-2014
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This study aimed to screen endophytic bacteria with 1-aminocyclopropane-1-carboxylate deaminase activity from Panax ginseng and test the capability of growth promotion to its host.
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[The assessment of ultrasonic measurement of superior vena cava blood flow for the volume responsiveness of patients with mechanical ventilation].
Zhonghua Wei Zhong Bing Ji Jiu Yi Xue
PUBLISHED: 09-19-2014
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To approach the evaluative effect of respiratory variation of superior vena cava peak flow velocity measured using transthoracic echocardiography (TTE) on fluid responsiveness in patients with mechanical ventilation.
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[Determination of activity of transglycosidase in diastatic enzyme by high performance liquid chromatography].
Se Pu
PUBLISHED: 09-05-2014
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An analytical method for the determination of the activity of transglycosidase in diastatic enzyme by high performance liquid chromatography (HPLC) was established. Taken as the substrate, maltose was transformed into trisaccharide by transglycosidase in a 37 degrees C water bath and acetic acid buffer solution (pH = 4.8) with acarbose as transglycosidase inhibitor. The transformation of the trisaccharide was detected on a SUGAR SH1011 column (300 mm x 8.0 mm, 6 microm) with 0.01 mol/L sulfuric acid solution as mobile phase at a flow rate of 0.6 mL/min and a differential refractive index detector (RID), in order that the activity of transglycosidase can be measured indirectly. The conditions such as the chromatographic conditions, the concentration of substrate, the usage of inhibitor, and the incubation time were investigated. Under the optimized separation conditions, the calibration curve of the trisaccharide showed good linearity within the mass concentrations of 0.1-10 g/L (r = 0.999 8). The limit of detection and the limit of quantitation for transglycosidase activity were 0.013 U and 0.043 U, respectively. The relative standard deviation was 0.63% for six parallel tests. The activities of transglycosidase from different batches of diastatic enzyme were also determined with good result. The method can be applied to determine the activity of transglycosidase in the diastatic enzyme of the producers' raw materials with the advantages of convenience, simplicity and stability.
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OptMAVEn--a new framework for the de novo design of antibody variable region models targeting specific antigen epitopes.
PLoS ONE
PUBLISHED: 08-25-2014
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Antibody-based therapeutics provides novel and efficacious treatments for a number of diseases. Traditional experimental approaches for designing therapeutic antibodies rely on raising antibodies against a target antigen in an immunized animal or directed evolution of antibodies with low affinity for the desired antigen. However, these methods remain time consuming, cannot target a specific epitope and do not lead to broad design principles informing other studies. Computational design methods can overcome some of these limitations by using biophysics models to rationally select antibody parts that maximize affinity for a target antigen epitope. This has been addressed to some extend by OptCDR for the design of complementary determining regions. Here, we extend this earlier contribution by addressing the de novo design of a model of the entire antibody variable region against a given antigen epitope while safeguarding for immunogenicity (Optimal Method for Antibody Variable region Engineering, OptMAVEn). OptMAVEn simulates in silico the in vivo steps of antibody generation and evolution, and is capable of capturing the critical structural features responsible for affinity maturation of antibodies. In addition, a humanization procedure was developed and incorporated into OptMAVEn to minimize the potential immunogenicity of the designed antibody models. As case studies, OptMAVEn was applied to design models of neutralizing antibodies targeting influenza hemagglutinin and HIV gp120. For both HA and gp120, novel computational antibody models with numerous interactions with their target epitopes were generated. The observed rates of mutations and types of amino acid changes during in silico affinity maturation are consistent with what has been observed during in vivo affinity maturation. The results demonstrate that OptMAVEn can efficiently generate diverse computational antibody models with both optimized binding affinity to antigens and reduced immunogenicity.
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N-terminal probrain natriuretic peptide levels as a predictor of functional outcomes in patients with ischemic stroke.
Neuroreport
PUBLISHED: 08-08-2014
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The prognostic value of the N-amino terminal fragment of the prohormone brain natriuretic peptide (NT-proBNP) in acute ischemic stroke (AIS) is uncertain. We sought to determine whether NT-proBNP levels were associated with functional outcomes after AIS. From August 2012 to October 2013, consecutive first-ever AIS patients admitted to the Department of Emergency of the First Affiliated Hospital of Xinxiang Medical University, China, were included in this study. Plasma NT-proBNP levels were measured from admission. Outcomes were measured as 90-day modified Rankin Scale score ('good outcome'=0-2 vs. 'poor'). Multivariate logistic regression was used to assess associations between NT-proBNP levels and outcomes. Predictive performance of NT-proBNP as compared with the clinical model was assessed by comparing receiver-operating characteristic curves. During this study period, 217 consecutive patients with AIS were included and completed 90 days of follow-up. There was a strong positive correlation between the plasma level of NT-proBNP and the National Institutes of Health Stroke Scale score (r=0.415, P=0.000). Plasma levels of NT-proBNP in patients with an unfavorable outcome were significantly higher than those in patients with a favorable outcome [3432 (interquartile range, 1100-54991) vs. 978 (interquartile range, 123-1705) pg/ml; P=0.000]. In multivariate analyses, after adjusting for all other significant outcome predictors, the NT-proBNP level that remained can be seen as an independent unfavorable outcome predictor, with an adjusted odds ratios of 4.14 (95% confidence interval, 2.72-7.99; P=0.000). Our results show that plasma NT-proBNP levels were significantly elevated in patients with an unfavorable outcome and might be of clinical importance as a supplementary tool for the assessment of functional outcomes in patients with AIS.
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Genomics in personalized cancer medicine and its impact on early drug development in China: report from the 6th Annual Meeting of the US Chinese Anti-Cancer Association (USCACA) at the 50th ASCO Annual Meeting.
Chin J Cancer
PUBLISHED: 08-07-2014
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The 6th Annual Meeting of the United States Chinese Anti-Cancer Association (USCACA) was held in conjunction with the 50th Annual Meeting of American Society of Clinical Oncology (ASCO) on May 30, 2014 in Chicago, Illinois, the United States of America. With a focus on personalized medicine, the conference featured novel approaches to investigate genomic aberrations in cancer cells and innovative clinical trial designs to expedite cancer drug development in biomarker-defined patient populations. A panel discussion further provided in-depth advice on advancing development of personalized cancer medicines in China. The conference also summarized USCACA key initiatives and accomplishments, including two awards designated to recognize young investigators from China for their achievements and to support their training in the United States. As an effort to promote international collaboration, USCACA will team up with Chinese Society of Clinical Oncology (CSCO) to host a joint session on "Breakthrough Cancer Medicines" at the upcoming CSCO Annual Meeting on September 20th, 2014 in Xiamen, China.
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The Connexin46 Mutant, Cx46T19M, Causes Loss of Gap Junction Function and Alters Hemi-channel Gating.
J. Membr. Biol.
PUBLISHED: 08-05-2014
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An N-terminal mutant of connexin46 (T19M) alters a highly conserved threonine and has been linked to autosomal dominant cataracts. To study the cellular and functional consequences of substitution of this amino acid, T19M was expressed in Xenopus oocytes and in HeLa cells. Unlike wild-type Cx46, T19M did not induce intercellular conductances in Xenopus oocytes. In transfected HeLa cells, T19M was largely localized within the cytoplasm, with drastically reduced formation of gap junction plaques. Expression of rat T19M was cytotoxic, as evidenced by an almost complete loss of viable cells expressing the mutant protein by 48-72 h following transfection. When incubated in medium containing physiological concentrations of divalent cations, T19M-expressing cells showed increased uptake of DAPI as compared with cells expressing wild-type Cx46, suggesting aberrant connexin hemi-channel activity. Time-lapse and dye uptake studies suggested that T19M hemi-channels had reduced sensitivity to Ca(2+). Whole cell patch clamp studies of single transfected HeLa cells demonstrated that rat T19M formed functional hemi-channels with altered voltage-dependent gating. These data suggest that T19M causes cataracts by loss of gap junctional channel function and abnormally increased hemi-channel activity. Furthermore, they implicate this conserved threonine in both gap junction plaque formation and channel/hemi-channel gating in Cx46.
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Genetic variation in the tissue factor gene is associated with clinical outcome in severe sepsis patients.
Crit Care
PUBLISHED: 08-03-2014
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IntroductionActivation of inflammation and coagulation was closely related and mutually interdependent in sepsis. Tissue factor (TF) and its endogenous inhibitor, tissue factor pathway inhibitor (TFPI) was the main regulators of the initiation of coagulation process. Altered plasma levels of TF and TFPI have been related to worse outcome in sepsis. The objective of this study was to investigate whether single nucleotide polymorphisms (SNPs) in the TF and TFPI genes were associated with risk and outcome for patients with severe sepsis.MethodsSeventeen SNPs in TF and TFPI were genotyped in samples of sepsis (n =577) and severe sepsis patients (n =476), and tested for association in this case¿control collection. We then investigated correlation between the associated SNPs and the mRNA expression, and protein level of the corresponding gene. The mRNA levels of TF were determined using real-time quantitative reverse transcription-polymerase chain reaction and the soluble plasma levels of TF were measured using enzyme linked immunosorbent assay (ELISA) method.ResultsAssociation analysis revealed that three TF SNPs in perfect linkage disequilibrium, rs1361600, rs3917615 and rs958587, were significantly associated with outcome of severe sepsis. G allele frequency of rs1361600 in survivor patients was significantly higher than that in nonsurvivor severe sepsis patients (P =4.91¿×¿10¿5, odds ratio (OR) =0.48, 95% confidence interval (CI) 0.33 to 0.69). The association remained significant after adjustment for covariates in multiple logistic regression analysis and for multiple comparisons. Lipopolysaccharide-induced TF-mRNA expression levels in peripheral blood mononuclear cells from subjects carrying rs1361600 AG and GG genotypes, were significantly lower than those subjects carrying AA genotype (P =0.0012). Moreover, severe sepsis patients of GG and GA genotypes showed lower serum levels of TF than patients with AA genotype (P adj =0.02). The plasma levels of TF were also associated with outcome of severe sepsis patients (P adj =0.01). However, genotype and allele analyses did not show any significant difference between sepsis and severe sepsis patients.ConclusionsOur findings indicate that common genetic variation in TF was significantly associated with outcome of severe sepsis in Chinese Han population.
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[Determination of N-nitrosodimethylamine in beer by frozen zone melting liquid-liquid extraction/gas chromatography].
Se Pu
PUBLISHED: 07-30-2014
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A simple and effective sample enrichment method of frozen zone melting liquid-liquid extraction was optimized and validated for the analysis of trace N-nitrosodimethylamine (NDMA) in beer samples. The method was based on high pressure liquid-liquid extraction with a low temperature frozen step. The 90 mL beer was placed in a container with 10 mL dichloromethane. After agitation, the sample was kept in a freezer for 16 h at -19 degrees C. The organic extract was analyzed by gas chromatography with a flame ionization detector (GC-FID). The accuracy, precision, detection and quantification limits and linearity of the method were evaluated. The results showed that the calibration curve of NDMA was linear in the range of 5-200 mg/L with a good correlation coefficient (r2) of 0.999 6. The recoveries at the spiked levels of 5, 10 and 20 mg/L were 84.94%, 83.24%, 85.14% with the relative standard deviations (n = 7) of 3.06%, 3.19%, 2.63%, respectively. The ordinary extraction method of N-nitrosodimethylamine in beer includes the four steps of low-temperature distillation, liquid-liquid extraction, rotary evaporation and nitrogen blowing concentration. With the extremely low volume of solvent used, the proposed extraction method proved to be easy and simple, and adequate for high-throughput analysis at low cost.
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Glycemic control in diabetes is restored by therapeutic manipulation of cytokines that regulate beta cell stress.
Nat. Med.
PUBLISHED: 07-18-2014
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In type 2 diabetes, hyperglycemia is present when an increased demand for insulin, typically due to insulin resistance, is not met as a result of progressive pancreatic beta cell dysfunction. This defect in beta cell activity is typically characterized by impaired insulin biosynthesis and secretion, usually accompanied by oxidative and endoplasmic reticulum (ER) stress. We demonstrate that multiple inflammatory cytokines elevated in diabetic pancreatic islets induce beta cell oxidative and ER stress, with interleukin-23 (IL-23), IL-24 and IL-33 being the most potent. Conversely, we show that islet-endogenous and exogenous IL-22, by regulating oxidative stress pathways, suppresses oxidative and ER stress caused by cytokines or glucolipotoxicity in mouse and human beta cells. In obese mice, antibody neutralization of IL-23 or IL-24 partially reduced beta cell ER stress and improved glucose tolerance, whereas IL-22 administration modulated oxidative stress regulatory genes in islets, suppressed ER stress and inflammation, promoted secretion of high-quality efficacious insulin and fully restored glucose homeostasis followed by restitution of insulin sensitivity. Thus, therapeutic manipulation of immune regulators of beta cell stress reverses the hyperglycemia central to diabetes pathology.
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miR-31 promotes proliferation of colon cancer cells by targeting E2F2.
Biotechnol. Lett.
PUBLISHED: 07-17-2014
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MicroRNA-31 (miR-31) plays important roles in colon cancer development. However, the underlying mechanism is still not clear. We have explored the functions of miR-31 on proliferation of colon cancer cells as well as the underlying mechanism. E2F2 was identified as a direct target of miR-31. miR-31 regulated the proliferation of colon cancer cells by targeting E2F2. Moreover, in the present study, E2F2 acted as a tumor suppressor in colon cancer by repressing the expression of survivin and regulating the expression of CCNA2, C-MYC, MCM4 and CDK2. A possible mechanism for the function of miR-31 on colon cancer proliferation is presented and indicates that miR-31 might become a target for anti-cancer drug design.
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Induced Pluripotent Stem Cells from Familial Alzheimer's Disease Patients Differentiate into Mature Neurons with Amyloidogenic Properties.
Stem Cells Dev.
PUBLISHED: 07-17-2014
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Although the majority of Alzheimer's disease (AD) cases are sporadic, about 5% of cases are inherited in an autosomal dominant pattern as familial AD (FAD) and manifest at an early age. Mutations in the presenilin 1 (PSEN1) gene account for the majority of early-onset FAD. Here, we describe the generation of virus-free human induced pluripotent stem cells (hiPSCs) derived from fibroblasts of patients harboring the FAD PSEN1 mutation A246E and fibroblasts from healthy age-matched controls using nonintegrating episomal vectors. We have differentiated these hiPSC lines to the neuronal lineage and demonstrated that hiPSC-derived neurons have mature phenotypic and physiological properties. Neurons from mutant hiPSC lines express PSEN1-A246E mutations themselves and show AD-like biochemical features, that is, amyloidogenic processing of amyloid precursor protein (APP) indicated by an increase in ?-amyloid (A?)42/A?40 ratio. FAD hiPSCs harboring disease properties can be used as humanized models to test novel diagnostic methods and therapies and explore novel hypotheses for AD pathogenesis.
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Direct application of gold nanoparticles to one-pot electrochemical biosensors.
Anal. Chim. Acta
PUBLISHED: 06-27-2014
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Gold nanoparticles (AuNPs) have been widely employed for the fabrication of electrochemical biosensors. In most cases, AuNPs are immobilized on the surface of an electrode, so they are difficult to be regenerated, making the use of the biosensor unfriendly. In this work, by adopting AuNPs directly as the electrolytes, we have developed a novel AuNPs-based electrochemical detection system. In brief, AuNPs-catalyzed oxidation of glucose is combined with a HRP-catalyzed reaction as well as an electrocatalytic reaction to compose cascade reactions in the electrolyte. Thus, the intensity of the electrocatalytic signals has quantitative relation with the concentration of glucose, and favors the sensitive detection of glucose. Furthermore, because the catalysis of AuNPs may be blocked under the interaction with single-stranded DNA and unblocked in the presence of a complementary sequence, detection of DNA and even single-nucleotide polymorphism can thereby been achieved. This one-pot detection system can be operated and regenerated very easily, since all the components are integrated in the electrolytes of AuNPs, and the unmodified electrode can be reused after being rinsed. This concept by integrating the advantages of sensitive electrochemical detection with the easy-to-operate nanocolloidal system may also promote the development of other kinds of electrochemical biosensors.
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Smart chemistry in polymeric nanomedicine.
Chem Soc Rev
PUBLISHED: 06-19-2014
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This review provides an overview of smart chemistry developed and utilized in the last 5-10 years in polymer-based drug delivery nanomedicine. Smart chemistry not only facilitates the controlled drug loading in a highly specific manner, but also potentially controls the drug release kinetics at the targeted tissues. This review highlights the emergence of new chemistry or unique utilization of conventional chemistry in drug delivery, which is believed to play an important role in developing next generation nanomedicine.
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Muscle-specific inhibition of the classical nuclear factor-?B pathway is protective against diaphragmatic weakness in murine endotoxemia.
Crit. Care Med.
PUBLISHED: 06-17-2014
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Diaphragmatic weakness and acute respiratory failure are common in sepsis. Nuclear factor-?B acts as a general coordinator of the systemic inflammatory response, but its role within the diaphragm itself during sepsis is unknown. We investigated the potential protective effect upon the diaphragm of inhibiting nuclear factor-?B only within muscle fibers during acute endotoxemia.
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Functional PEG-PAMAM-tetraphosphonate capped NaLnF? nanoparticles and their colloidal stability in phosphate buffer.
Langmuir
PUBLISHED: 06-05-2014
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Developing surface coatings for NaLnF4 nanoparticles (NPs) that provide long-term stability in solutions containing competitive ions such as phosphate remains challenging. An amine-functional polyamidoamine tetraphosphonate (NH2-PAMAM-4P) as a multidentate ligand for these NPs has been synthesized and characterized as a ligand for the surface of NaGdF4 and NaTbF4 nanoparticles. A two-step ligand exchange protocol was developed for introduction of the NH2-PAMAM-4P ligand on oleate-capped NaLnF4 NPs. The NPs were first treated with methoxy-poly(ethylene glycol)-monophosphoric acid (M(n) = 750) in tetrahydrofuran. The mPEG750-OPO3-capped NPs were stable colloidal solutions in water, where they could be ligand-exchanged with NH2-PAMAM-4P. The surface amine groups on the NPs were available for derivatization to attach methoxy-PEG (M(n) = 2000) and biotin-terminated PEG (M(n) = 2000) chains. The surface coverage of ligands on the NPs was examined by thermal gravimetric analysis, and by a HABA analysis for biotin-containing NPs. Colloidal stability of the NPs was examined by dynamic light scattering. NaGdF4 and NaTbF4 NPs capped with mPEG2000-PAMAM-4P showed colloidal stability in DI water and in phosphate buffer (10 mM, pH 7.4). A direct comparison with NaTbF4 NPs capped with a mPEG2000-lysine-based tetradentate ligand that we reported previously (Langmuir 2012, 28, 12861-12870) showed that both ligands provided long-term stability in phosphate buffer, but that the lysine-based ligand provided better stability in phosphate-buffered saline.
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Synthesis of monodisperse nanocolloidal microspheres with controlled size by vesicle bilayer templating.
Chem. Commun. (Camb.)
PUBLISHED: 05-30-2014
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This study describes a new method to prepare monodisperse polystyrene (PS) colloidal nanoparticles with controlled size ranging from 60 nm to 140 nm by the direct polymerization of styrene and divinylbenzene inside the bilayers of the polydisperse hyperbranched polymer vesicles.
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Comparison of reprogramming genes in induced pluripotent stem cells and nuclear transfer cloned embryos.
Stem Cell Rev
PUBLISHED: 05-16-2014
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The most effective reprogramming methods, somatic cell nuclear transfer (SCNT) and induced pluripotent stem cells (iPSCs), are widely used in biological research and regenerative medicine, yet the mechanism that reprograms somatic cells to totipotency remains unclear and thus reprogramming efficiency is still low. Microarray technology has been employed in analyzing the transcriptomes changes during iPS reprogramming. Unfortunately, it is difficult to obtain enough DNA from SCNT reconstructed embryos to take advantage of this technology. In this study, we aimed to identify critical genes from the transcriptional profile for iPS reprogramming and compared expression levels of these genes in SCNT reprogramming. By integrating gene expression information from microarray databases and published studies comparing somatic cells with either miPSCs or mouse embryonic stem cells (ESCs), we obtained two lists of co-upregulated genes. The gene ontology (GO) enriched analysis of these two lists demonstrated that the reprogramming process is associated with numerous biological processes. Specifically, we selected 32 genes related to heterochromatin, embryonic development, and cell cycle from our co-upregulated gene datasets and examined the gene expression level in iPSCs and SCNT embryos by qPCR. The results revealed that some reprogramming related genes in iPSCs were also expressed in SCNT reprogramming. We established the network of gene interactions that occur with genes differentially expressed in iPS and SCNT reprogramming and then performed GO analysis on the genes in the network. The network genes function in chromatin organization, heterochromatin, transcriptional regulation, and cell cycle. Further researches to improve reprogramming efficiency, especially in SCNT, will focus on functional studies of these selected genes.
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GTS-21, an ?7-nicotinic acetylcholine receptor agonist, modulates Th1 differentiation in CD4(+) T cells from patients with rheumatoid arthritis.
Exp Ther Med
PUBLISHED: 05-15-2014
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GTS-21 (also known as DMBX-anabaseine), a selective ?7 nicotinic acetylcholine receptor (?7nAChR) agonist, has previously been found to inhibit the inflammation associated with rheumatoid arthritis (RA). RA is an autoimmune disease, where an abnormal immune system plays a critical role in the occurrence and development of synovium inflammation and bone damage. However, prior to this study, the immunological mechanism by which GTS-21 protects against RA had not been elucidated. In the present study, the effects of GTS-21 on T helper 1 (Th1) cells, which have an important role in the inflammation associated with RA, were investigated. Peripheral blood mononuclear cells (PBMCs) and cluster of differentiation (CD)4(+) T cells were separated from patients with RA, and the effects of GTS-21 on PBMCs stimulated with anti-CD3/-CD28 antibodies and CD4(+) T cells were investigated in the context of Th1-cell differentiation. ELISA was used to analyze interferon (IFN)-? expression and flow cytometric analysis was used to detect the percentage of IFN-?(+) CD3(+)CD8(-) T cells. In addition, western blotting was employed to detect the levels of the T-box transcription factor TBX21, which is a Th1 cell-specific transcription factor. The present study showed that GTS-21 reduced IFN-? production in PBMCs from patients with RA. Under conditions of Th1-cell differentiation, GTS-21 reduced the percentage of IFN?(+)CD3(+)CD8(-) T cells and IFN-? production in the culture supernatant and also inhibited the expression of the Th1 cell-specific transcription factor TBX21. The effects of GTS-21 were blocked by the ?7nAchR antagonist ?-bungarotoxin, which increased the expression of IFN-? and TBX21. This study demonstrated that GTS-21 is able to inhibit RA Th1-cell differentiation through activation of the ?7nAchR.
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Image-contrast technology based on the electrochemiluminescence of porous silicon and its application in fingerprint visualization.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 05-04-2014
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The electrochemiluminescence (ECL) of porous silicon (pSi) has attracted great interest for its potential application in display technology and chemical sensors. In this study, we found that pSi with a different surface chemistry displayed an apparently different dynamic ECL process. An image-contrast technology was established on the basis of the intrinsic mechanism of the ECL dynamic process. As a proof of principle, the visualization of latent fingerprints (LFPs) and in?situ detection of TNT in fingerprints was demonstrated by using the ECL-based image-contrast technology.
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Identification of differentially methylated genes in the malignant transformation of ovarian endometriosis.
J Ovarian Res
PUBLISHED: 04-25-2014
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Key roles for epigenetic mechanisms in tumorigenesis are well accepted, while the relationship between gene methylation and malignant transformation of ovarian endometriosis (EMS) was seldom reported. In this study, we aimed to screen for aberrantly methylated genes associated with the malignant transformation of ovarian EMS and to preliminarily verify the reliability of screened results by detecting the methylation status and protein expression of the candidate gene in a larger scale of formaldehyde-fixed and paraffin-embedded (FFPE) samples.
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Nanojunction-mediated photocatalytic enhancement in heterostructured CdS/ZnO, CdSe/ZnO, and CdTe/ZnO nanocrystals.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 04-19-2014
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A series of highly efficient semiconductor nanocrystal (NC) photocatalysts have been synthesized by growing wurtzite-ZnO tetrahedrons around pre-formed CdS, CdSe, and CdTe quantum dots (QDs). The resulting contact between two small but high-quality crystals creates novel CdX/ZnO heterostructured semiconductor nanocrystals (HSNCs) with extensive type-II nanojunctions that exhibit more efficient photocatalytic decomposition of aqueous organic molecules under UV irradiation. Catalytic testing and characterization indicate that catalytic activity increases as a result of a combination of both the intrinsic chemistry of the chalcogenide anions and the heterojunction structure. Atomic probe tomography (APT) is employed for the first time to probe the spatial characteristics of the nanojunction between cadmium chalcogenide and ZnO crystalline phases, which reveals various degrees of ion exchange between the two crystals to relax large lattice mismatches. In the most extreme case, total encapsulation of CdTe by ZnO as a result of interfacial alloying is observed, with the expected advantage of facilitating hole transport for enhanced exciton separation during catalysis.
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Active and passive demethylation of male and female pronuclear DNA in the Mammalian zygote.
Cell Stem Cell
PUBLISHED: 04-11-2014
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The epigenomes of mammalian sperm and oocytes, characterized by gamete-specific 5-methylcytosine (5mC) patterns, are reprogrammed during early embryogenesis to establish full developmental potential. Previous studies have suggested that the paternal genome is actively demethylated in the zygote while the maternal genome undergoes subsequent passive demethylation via DNA replication during cleavage. Active demethylation is known to depend on 5mC oxidation by Tet dioxygenases and excision of oxidized bases by thymine DNA glycosylase (TDG). Here we show that both maternal and paternal genomes undergo widespread active and passive demethylation in zygotes before the first mitotic division. Passive demethylation was blocked by the replication inhibitor aphidicolin, and active demethylation was abrogated by deletion of Tet3 in both pronuclei. At actively demethylated loci, 5mCs were processed to unmodified cytosines. Surprisingly, the demethylation process was unaffected by the deletion of TDG from the zygote, suggesting the existence of other demethylation mechanisms downstream of Tet3-mediated oxidation.
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Multiple Mechanisms in Renal Artery Stenosis-Induced Renal Interstitial Fibrosis.
Nephron Exp. Nephrol.
PUBLISHED: 04-09-2014
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Background/Aims: Renal artery stenosis (RAS), which may lead to renal fibrosis, is a common cause of end-stage renal disease in elderly patients. However, the potential mechanisms leading to the development of renal fibrosis and atrophy have not been clarified. Methods: A two-kidney, one-clip Goldblatt mouse model was established in the present study. Blood pressure, morphological and pathological alterations were examined on days 7, 14, and 28 after surgery. Peritubular capillary loss and pericyte changes after injury were evaluated. Inflammatory macrophage infiltration and Wnt/?-catenin signaling were also investigated. Results: A significant increase in blood pressure and obvious renal atrophy were observed on days 7, 14, and 28 after surgery. Following surgery, the clipped kidneys developed aggravated interstitial fibrosis and tubular epithelial injury over time. Moreover, RAS induced obvious peritubular capillary loss and inflammatory macrophage infiltration. Increased pericyte number was found in the clipped kidneys, but these cells detached from the endothelial cells and migrated to the interstitium. Wnt/?-catenin signaling was also significantly upregulated in the clipped kidneys after surgery. Conclusion: Our study provides a novel insight into the mechanisms linking peritubular capillary loss and pericyte changes in RAS-induced renal fibrosis. Our findings also suggest that inflammatory macrophages and Wnt/?-catenin signaling participate in these pathological processes. Therefore, multi-target therapeutic strategies may significantly contribute to the prevention of renal interstitial fibrosis and the preservation of renal function in patients with RAS. © 2014 S. Karger AG, Basel.
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FOXO1 3'UTR functions as a ceRNA in repressing the metastases of breast cancer cells via regulating miRNA activity.
FEBS Lett.
PUBLISHED: 04-04-2014
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The competitive endogenous RNAs (ceRNAs) are RNA molecules that affect each other's expression through competition for their shared microRNAs (miRNAs). In this study we explored whether FOXO1 3'UTR can function as a ceRNA in repressing epithelial-to-mesenchymal transition (EMT) and metastasis of breast cancer cells via regulating miR-9 activity. We found that miR-9 binds to both the FOXO1- and E-cadherin-3'UTR, indicating that the FOXO1- and E-cadherin-3'UTR can be linked through miR-9. Follow-up analyses showed that there existed a competition of miR-9 between FOXO1 and E-cadherin-3'UTR. Thus FOXO1 3'UTR inhibits the metastases of breast cancer cells via induction of E-cadherin expression. Our results suggest that FOXO1 3'UTR may function as a miRNA-inhibitor in modulating metastasis of breast cancer cells.
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Transcriptomic analysis of the phytopathogenic oomycete Phytophthora cactorum provides insights into infection-related effectors.
BMC Genomics
PUBLISHED: 03-31-2014
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Phytophthora cactorum, a hemibiotrophic oomycete pathogen, can cause destructive diseases on numerous crops worldwide, leading to essential economic losses every year. However, little has been known about its molecular pathogenicity mechanisms. To gain insight into its repertoire of effectors, the P. cactorum transcriptome was investigated using Illumina RNA-seq.
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Therapeutic efficacy of the multi-epitope vaccine CTB-UE against Helicobacter pylori infection in a Mongolian gerbil model and its microRNA-155-associated immuno-protective mechanism.
Vaccine
PUBLISHED: 03-28-2014
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Vaccination is an effective means of preventing infectious diseases, including those caused by Helicobacter pylori. In this study, we constructed a novel multi-epitope vaccine, CTB-UE, composed of the cholera toxin B subunit and tandem copies of the B and Th cell epitopes from the H. pylori urease A and B subunits. We evaluated the therapeutic efficacy of the multi-epitope vaccine CTB-UE against H. pylori infection in a Mongolian gerbil model and studied its immuno-protective mechanisms. The experimental results indicated that urease activity, H. pylori colonisation density, the levels of IL-8 and TNF-? in the serum, and the levels of COX-2 and NAP in gastric tissue were significantly lower and the IgG level in the serum and the IFN-? level in spleen lymphocytes were significantly higher in the vaccinated group compared with the model control group; additionally, gastric mucosal inflammation was notably alleviated following vaccination. The results showed that CTB-UE had a good therapeutic effect on H. pylori infection. The immuno-protective mechanism was closely related to the immune response mediated by microRNA-155, the expression of which was strongly up-regulated after CTB-UE administration. The expression levels of the microRNA-155 target proteins IFN-?R?, AID, and PU.1 were significantly down-regulated; these results indicated that CTB-UE induced an immune response biased towards Th1 cells by up-regulating microRNA-155 to inhibit IFN-?R? expression and induced a humoral immune response towards B cells by up-regulating microRNA-155 to inhibit PU.1 and AID expression. These results demonstrate that the multi-epitope vaccine CTB-UE may be a promising therapeutic vaccine against H. pylori infection and is a new therapeutic tool for human use.
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Comparison of Abbott and Da-an real-time PCR for quantitating serum HBV DNA.
World J. Gastroenterol.
PUBLISHED: 03-27-2014
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To compare the performance of the Da-an real-time hepatitis B virus (HBV) DNA assay and Abbott RealTime HBV assay.
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Synaptotagmin 1 and Ca2+ drive trans SNARE zippering.
Sci Rep
PUBLISHED: 03-17-2014
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Synaptotagmin 1 (Syt1) is a major Ca(2+)-sensor that evokes neurotransmitter release. Here we used site-specific fluorescence resonance energy transfer (FRET) assay to investigate the effects of Syt1 on SNAREpin assembly. C2AB, a soluble version of Syt1, had virtually no stimulatory effect on the rate of the FRET at N-terminus of SNARE complex both with and without Ca(2+), indicating C2AB does not interfere with the initial nucleation of SNARE assembly. However, C2AB-Ca(2+) accelerated the FRET rate significantly at membrane proximal region, indicating C2AB-Ca(2+) promotes the transition from a partially assembled SNARE complex to the fusion-competent SNAREpin. Similar enhancement was also observed at the end of the transmembrane domain of SNARE proteins. The stimulatory effect disappeared if there was no membrane or only neutral membrane present.
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DJ-1 mediates the resistance of cancer cells to dihydroartemisinin through reactive oxygen species removal.
Free Radic. Biol. Med.
PUBLISHED: 03-17-2014
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Dihydroartemisinin (DHA), one of the main metabolites of artemisinin and its derivatives, presents anti-cancer potential in vitro and in vivo. To explore the mechanisms of resistance toward DHA, a DHA-resistant cell line, HeLa/DHA, was established with a resistance factor of 7.26 in vitro. Upon DHA treatment, apoptotic cells were significantly elicited in parental HeLa cells but minimally induced in HeLa/DHA cells. HeLa/DHA cells also displayed much less sensitivity to DHA-induced tumor suppression in cancer xenograft models than HeLa cells. Intriguingly, DHA-resistant cells did not display a multidrug-resistant phenotype. Based on a proteomic study employing LC-ESI-MS/MS together with pathway analysis, DJ-1 (PARK7) was found to be highly expressed in HeLa/DHA cells. Western blot and immunofluorescence assays confirmed the higher expression of DJ-1 in HeLa/DHA cells than in parental cells in both cell line and xenograft models. DJ-1 is translocated to the mitochondria of HeLa/DHA cells and oxidized, providing DJ-1 with stronger cytoprotection activity. Further study revealed that DJ-1 knockdown in HeLa/DHA cells abolished the observed resistance, whereas overexpression of DJ-1 endowed the parental HeLa cells with resistance toward DHA. Reactive oxygen species (ROS) were also significantly induced by either DHA or hydrogen peroxide in HeLa cells but not in resistant HeLa/DHA cells. When the cells were pretreated with N-acetyl-l-cysteine, the effect of DJ-1 knockdown on sensitizing HeLa/DHA cells to DHA was significantly attenuated. In summary, our study suggests that overexpression and mitochondrial translocation of DJ-1 provides HeLa/DHA cells with resistance to DHA-induced ROS and apoptosis.
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Impact of ground- and excited-state aromaticity on cyclopentadiene and silole excitation energies and excited-state polarities.
Chemistry
PUBLISHED: 03-12-2014
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A new qualitative model for estimating the properties of substituted cyclopentadienes and siloles in their lowest ??* excited states is introduced and confirmed through quantum chemical calculations, and then applied to explain earlier reported experimental excitation energies. According to our model, which is based on excited-state aromaticity and antiaromaticity, siloles and cyclopentadienes are cross-hyperconjugated "aromatic chameleons" that adapt their electronic structures to conform to the various aromaticity rules in different electronic states (Hückel's rule in the ?(2) electronic ground state (S0) and Baird's rule in the lowest ??* excited singlet and triplet states (S1 and T1)). By using pen-and-paper arguments, one can explain polarity changes upon excitation of substituted cyclopentadienes and siloles, and one can tune their lowest excitation energies by combined considerations of ground- and excited-state aromaticity/antiaromaticity effects. Finally, the "aromatic chameleon" model can be extended to other monocyclic compound classes of potential use in organic electronics, thereby providing a unified view of the S0, T1, and S1 states of a range of different cyclic cross-?-conjugated and cross-hyperconjugated compound classes.
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A high-sensitivity lanthanide nanoparticle reporter for mass cytometry: tests on microgels as a proxy for cells.
Langmuir
PUBLISHED: 03-11-2014
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This paper addresses the question of whether one can use lanthanide nanoparticles (e.g., NaHoF4) to detect surface biomarkers expressed at low levels by mass cytometry. To avoid many of the complications of experiments on live or fixed cells, we carried out proof-of-concept experiments using aqueous microgels with a diameter on the order of 700 nm as a proxy for cells. These microgels were used to test whether nanoparticle (NP) reagents would allow the detection of as few as 100 proteins per "cell" in cell-by-cell assays. Streptavidin (SAv), which served as the model biomarker, was attached to the microgel in two different ways. Covalent coupling to surface carboxyls of the microgel led to large numbers (>10(4)) of proteins per microgel, whereas biotinylation of the microgel followed by exposure to SAv led to much smaller numbers of SAv per microgel. Using mass cytometry, we compared two biotin-containing reagents, which recognized and bound to the SAvs on the microgel. One was a metal chelating polymer (MCP), a biotin end-capped polyaspartamide containing 50 Tb(3+) ions per probe. The other was a biotinylated NaHoF4 NP containing 15?000 Ho atoms per probe. Nonspecific binding was determined with bovine serum albumin (BSA) conjugated microgels. The MCP was effective at detecting and quantifying SAvs on the microgel with covalently bound SAv (20?000 SAvs per microgel) but was unable to give a meaningful signal above that of the BSA-coated microgel for the samples with low levels of SAv. Here the NP reagent gave a signal 2 orders of magnitude stronger than that of the MCP and allowed detection of NPs ranging from 100 to 500 per microgel. Sensitivity was limited by the level of nonspecific adsorption. This proof of concept experiment demonstrates the enhanced sensitivity possible with NP reagents in cell-by-cell assays by mass cytometry.
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Extraction and in vitro antioxidant activity of exopolysaccharide by Pleurotus eryngii SI-02.
Braz. J. Microbiol.
PUBLISHED: 03-10-2014
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The extraction parameters for Pleurotus eryngii SI-02 exopolysaccharide (EPS) produced during submerged culture were optimized using response surface methodology (RSM). The optimum conditions for EPS extraction were predicted to be, precipitation time 20.24 h, ethanol concentration 89.62% and pH 8.17, and EPS production was estimated at 7.27 g/L. The actual yield of EPS under these conditions was 7.21 g/L. The in vitro antioxidant results of the EPS showed that the inhibition effects of EPS at a dosage of 400 mg/L on hydroxyl, superoxide anion and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals were 59.63 ± 3.72%, 38.69 ± 2.59%, and 66.36 ± 4.42%, respectively, which were 12.74 ± 1.03%, 8.01 ± 0.56%, and 12.19 ± 1.05% higher than that of butylated hydroxytoluene (BHT), respectively. The reducing power of EPS of P. eryngii SI-02 was 0.98 ± 0.05, 60.66 ± 5.14% higher than that of BHT. The results provide a reference for large-scale production of EPS by P. eryngii SI-02 in industrial fermentation and the EPS can be used as a potential antioxidant which enhances adaptive immune responses.
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Molecular phylogenetic analysis of the Amiota taurusata species group within the Chinese species, with descriptions of two new species.
J. Insect Sci.
PUBLISHED: 02-28-2014
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The relationships among six species of the Amiota taurusata Takada, Beppu, & Toda (Diptera: Drosophilidae) species group were investigated based on DNA sequence data of the mitochondrial NADH dehydrogenase subunit 2 ( ND2) gene, using three species of the genus Amiota as outgroups. A mitochondrial gene, cytochrome c oxidase I ( COI), can be used to discriminate between species of the taurusata group. Two new species are described from South China: A. protuberantis Shao et Chen, sp. nov. and A. shennongi Shao et Chen, sp. nov. A key to all the species of the taurusata group based on morphological characters is provided.
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Xiangshaliujunzi Decoction for the treatment of diabetic gastroparesis: a systematic review.
World J. Gastroenterol.
PUBLISHED: 02-28-2014
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To assess the current clinical evidence of the effectiveness of Xiangshaliujunzi Decoction (XSLJZD) for the treatment of diabetic gastroparesis (DGP).
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Effects of dimethyl sulfoxide on asymmetric division and cytokinesis in mouse oocytes.
BMC Dev. Biol.
PUBLISHED: 02-27-2014
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Dimethyl sulfoxide (DMSO) is used extensively as a permeable cryoprotectant and is a common solvent utilized for several water-insoluble substances. DMSO has various biological and pharmacological activities; however, the effect of DMSO on mouse oocyte meiotic maturation remains unknown.
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Combination of symptoms, syndrome and disease: treatment of refractory diabetic gastroparesis.
World J. Gastroenterol.
PUBLISHED: 02-24-2014
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To assess effect of combination of symptoms, syndrome and disease on treatment of diabetic gastroparesis with severe nausea and vomiting.
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Clinical efficacy of aconitum-containing traditional Chinese medicine for diabetic peripheral neuropathic pain.
Am. J. Chin. Med.
PUBLISHED: 01-29-2014
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Diabetic peripheral neuropathy is a common chronic complication of diabetes. Routine clinical management uses analgesics to relieve pain in combination with drugs for nerve repair. The drugs are often not effective for the severe pain cases, and these western medications also have side effects. We report a more effective treatment of diabetic peripheral neuropathic pain using a high dose of a traditional Chinese medicine, aconitum (including both Radix aconite preparata and Radix aconite kusnezoffii), in combination with Huangqi Guizhi Wuwu Tang (i.e., astragalus, cassia twig, white peony root, and spatholobi). In order to achieve stronger analgesic effects, we increased the clinical dosage of aconitum from 15 to 120 g. The aconitum was boiled for 6-8 hours, and licorice was also used to reduce potential toxicities of aconitum. In the four reported cases, the patients' neuropathic pain was remarkably reduced and the EMG profile was also improved with this treatment regimen. Adverse reactions were not observed during the therapy. Thus, aconitum represents a promising and safe treatment for the well-being of patients and their diabetic peripheral neuropathic pain. Future controlled clinical trials using traditional Chinese medicines containing aconitum in treating the neuropathic pain are warranted.
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Thin film fabricated from solution-dispersible porous hyperbranched conjugated polymer nanoparticles without surfactants.
Nanoscale
PUBLISHED: 01-16-2014
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Porous hyperbranched conjugated polymer nanoparticles with an average particle size of 20-60 nm and a specific surface area of 225 m(2) g(-1) have been prepared through Suzuki polymerization in a miniemulsion, which could be stably dispersed in common organic solvents after complete removal of surfactants. Furthermore, a simple spin-coating method for the preparation of homogeneous transparent thin films of the nanoparticle has been developed. Bright blue emission of the porous nanoparticle films could be reversibly quenched by nitroaromatics with enhanced sensitivity compared to dense films of the linear conjugated polymer analogue.
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Treatment of refractory diabetic gastroparesis: Western medicine and traditional Chinese medicine therapies.
World J. Gastroenterol.
PUBLISHED: 01-13-2014
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Refractory diabetic gastroparesis (DGP), a disorder that occurs in both type 1 and type 2 diabetics, is associated with severe symptoms, such as nausea and vomiting, and results in an economic burden on the health care system. In this article, the basic characteristics of refractory DGP are reviewed, followed by a discussion of therapeutic modalities, which encompasses the definitions and clinical manifestations, pathogenesis, diagnosis, and therapeutic efficacy evaluation of refractory DGP. The diagnostic standards assumed in this study are those set forth in the published literature due to the absence of recognized diagnosis criteria that have been assessed by an international organization. The therapeutic modalities for refractory DGP are as follows: drug therapy, nutritional support, gastric electrical stimulation, pyloric botulinum toxin injection, endoscopic or surgical therapy, and traditional Chinese treatment. The therapeutic modalities may be used alone or in combination. The use of traditional Chinese treatments is prevalent in China. The effectiveness of these therapies appears to be supported by preliminary evidence and clinical experience, although the mechanisms that underlie these effects will require further research. The purpose of this article is to explore the potential of combined Western and traditional Chinese medicine treatment methods for improved patient outcomes in refractory DGP.
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Cx46 hemichannels contribute to the sodium leak conductance in lens fiber cells.
Am. J. Physiol., Cell Physiol.
PUBLISHED: 01-08-2014
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The lens is proposed to have an internal microcirculation system consisting of continuously circulating ionic fluxes that play an essential role in maintaining lens transparency. One of the key components of this system is the sodium leak conductance. Here we investigate the contribution of Cx46 hemichannels to the basal membrane permeability of peripheral fiber cells isolated from transgenic mouse lenses lacking Cx50 or both Cx50 and Cx46 (dKO) using the whole cell patch-clamp technique. Our results show that Cx46 hemichannels were largely closed at a resting voltage of -60 mV in the presence of millimolar divalent cation concentrations. However, even though the vast majority of these channels were closed at -60 mV, a small, persistent, inward current could still be detected. This current could be mostly blocked by exposure to 1 mM La(3+) and was not observed in fiber cells isolated from dKO mouse lenses suggesting that it was due to Cx46 hemichannels. In addition, Cx50(-/-) fiber cells showed increased open channel noise and a depolarized resting potential compared with dKO fiber cells. Exposure of Cx50(-/-) fiber cells to La(3+) hyperpolarized the resting potential to -58 mV, which is similar to the value of resting potential measured in dKO fiber and significantly reduced the open channel noise. In conclusion, these results suggest that Cx46 hemichannels may contribute to the sodium leak conductance in lens fiber cells.
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Preparation of sustained-release composite coating formed by dexamethasone and oxidated sodium alginate.
Int J Clin Exp Med
PUBLISHED: 01-01-2014
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Inflammatory reaction and thrombosis are the unsolved main problems of non-coated biomaterials applied in cardiac surgery. In the present study, a series of sustained composite coating was prepared and characterized, such as in the chemical modification of polyvinyl chloride (PVC) for applications in cardiac surgery and the assessment of the biological property of modified PVC. The composite coatings were mainly formed by dexamethasone (DXM) and oxidated sodium alginate (OSA) through ionic and covalent bond methods. The biocompatibility and hemocompatibility of the coating surface were evaluated. Scanning electron microscopy analysis of the surface morphologies of the thrombus and platelets revealed that DXM-OSA coating improved the antithrombogenicity and biocompatibility of PVC circuits, which were essential for cardiac pulmonary bypass surgery. Evaluation of in vitro release revealed that the DXM on group PPC was gradually released in 8 h. Thus, DXM that covalently combined on the PVC surface showed sustained release. By contrast, DXM on groups PPI and PPD was quickly or shortly released, suggesting that groups PPI and PPD did not have sustained-release property. Overall, results indicated that the DXM-OSA composite coating may be a promising coating for the sustained delivery of DXM.
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Preclinical evaluation of recombinant human IFN?2b-containing magnetoliposomes for treating hepatocellular carcinoma.
Int J Nanomedicine
PUBLISHED: 01-01-2014
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Magnetoliposomes are phospholipid vesicles encapsulating magnetic nanoparticles that can be used to encapsulate therapeutic drugs for delivery into specific organs. Herein, we developed magnetoliposomes containing recombinant human IFN?2b, designated as MIL, and evaluated this combination's biological safety and therapeutic effect on both cellular and animal hepatocellular carcinoma models. Our data showed that MIL neither hemolyzed erythrocytes nor affected platelet-aggregation rates in blood. Nitroblue tetrazolium-reducing testing showed that MIL did not change the absolute numbers or phagocytic activities of leukocytes. Acute-toxicity testing also showed that MIL had no devastating effect on mice behaviors. All the results indicated that the nanoparticles could be a safe biomaterial. Pharmacokinetic analysis and tissue-distribution studies showed that MIL maintained stable and sustained drug concentrations in target organs under a magnetic field, helped to increase bioavailability, and reduced administration time. MIL also dramatically inhibited the growth of hepatoma cells. Targeting of MIL in the livers of nude mice bearing human hepatocellular carcinoma showed that MIL significantly reduced the tumor size to 38% of that of the control group. Further studies proved that growth inhibition of cells or tumors was due to apoptosis-signaling pathway activation by human IFN?2b.
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Comparative transcriptome analysis of climacteric fruit of Chinese pear (Pyrus ussuriensis) reveals new insights into fruit ripening.
PLoS ONE
PUBLISHED: 01-01-2014
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The fruit of Pyrus ussuriensis is typically climacteric. During ripening, the fruits produce a large amount of ethylene, and their firmness drops rapidly. Although the molecular basis of climacteric fruit ripening has been studied in depth, some aspects remain unclear. Here, we compared the transcriptomes of pre- and post-climacteric fruits of Chinese pear (P. ussuriensis c.v. Nanguo) using RNA-seq. In total, 3,279 unigenes were differentially expressed between the pre- and post-climacteric fruits. Differentially expressed genes (DEGs) were subjected to Gene Ontology analysis, and 31 categories were significantly enriched in the groups 'biological process', 'molecular function' and 'cellular component'. The DEGs included genes related to plant hormones, such as ethylene, ABA, auxin, GA and brassinosteroid, and transcription factors, such as MADS, NAC, WRKY and HSF. Moreover, genes encoding enzymes related to DNA methylation, cytoskeletal proteins and heat shock proteins (HSPs) showed differential expression between the pre- and post-climacteric fruits. Select DEGs were subjected to further analysis using quantitative RT-PCR (qRT-PCR), and the results were consistent with those of RNA-seq. Our data suggest that in addition to ethylene, other hormones play important roles in regulating fruit ripening and may interact with ethylene signaling during this process. DNA methylation-related methyltransferase and cytoskeletal protein genes are also involved in fruit ripening. Our results provide useful information for future research on pear fruit ripening.
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Regeneration of Solanum nigrum by somatic embryogenesis, involving frog egg-like body, a novel structure.
PLoS ONE
PUBLISHED: 01-01-2014
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A new protocol was established for the regeneration of Solanum nigrum by frog egg-like bodies (FELBs), which are novel somatic embryogenesis (SE) structures induced from the root, stem, and leaf explants. The root, stem, and leaf explants (93.33%, 85.10%, and 100.00%, respectively) were induced to form special embryonic calli on Murashige and Skoog (MS) medium containing 1.0 mg/L 2,4-dichlorophenoxyacetic acid, under dark condition. Further, special embryonic calli from the root, stem, and leaf explants (86.97%, 83.30%, and 99.47%, respectively) were developed into FELBs. Plantlets of FELBs from the three explants were induced in vitro on MS medium supplemented with 5.0 mg/L 6-benzylaminopurine and 0.1 mg/L gibberellic acid, and 100.00% plantlet induction rates were noted. However, plantlet induction in vivo on MS medium supplemented with 20 mg/L thidiazuron showed rates of 38.63%, 15.63%, and 61.30% for the root, stem, and leaf explants, respectively, which were lower than those of the in vitro culture. Morphological and histological analyses of FELBs at different development stages revealed that they are a novel type of SE structure that developed from the mesophyll (leaf) or cortex (stem and root) cells of S. nigrum.
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[Efficacy of postoperative simple chemotherapy and concurrent chemoradiotherapy in FIGO stage IB2-IIB cervical cancer].
Beijing Da Xue Xue Bao
PUBLISHED: 12-18-2013
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To evaluate the effectiveness of neoadjuvant chemotherapy (NAC) followed by radical hysterectomy plus postoperative chemotherapy but no radiotherapy for stage IB2-IIB cervical cancer.
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[Protection of huanglian jiedu decoction on livers of hyperlipidemia mice].
Zhongguo Zhong Xi Yi Jie He Za Zhi
PUBLISHED: 12-12-2013
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To observe the protection of Huanglian Jiedu Decoction (HJD) on high fat diet induced liver damage mice [hyperlipidemic mice lacking apolipoprotein E (ApoE(-/-))].
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Complementary and alternative medicine is expected to make greater contribution in controlling the prevalence of influenza.
Biosci Trends
PUBLISHED: 11-19-2013
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Influenza pandemics are a serious threat to public health in todays world. In the past 10 years, the outbreak of three forms of severe influenza--H5N1, H1N1, and H7N9--has caused tremendous loss of life and property. In order to better cope with pandemics, antivirals such as oseltamivir are being stockpiled in great quantities, placing a substantial burden on government budgets and potentially resulting in massive waste because of the uncertainty as to when an influenza pandemic will strike and whether emerging virus strains will be resistant to the stockpiled drugs. Complementary and alternative medicine (CAM) is generally available, affordable, and commonly used in China and many other countries and CAM has a long track record of fighting influenza. The Chinese Government appropriated funds to intensively investigate herbal medicines in accordance with the principles of evidence-based medicine in order to identify effective, inexpensive, and easily stockpiled medicines. Thus far, several drugs including Shufeng Jiedu capsules, Lianhua Qingwen capsules, Maxing Shigan decoction, Yinqiao powder, and Jinhua Qinggan granules have demonstrated effectiveness in fighting influenza. In the future, CAM is expected to make greater contribution in controlling the prevalence of influenza pandemics.
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Flight performance of the orange wheat blossom midge (Diptera: Cecidomyiidae).
J. Econ. Entomol.
PUBLISHED: 11-15-2013
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The orange wheat blossom midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), is a chronic wheat pest worldwide. Adult S. mosellana engage in short-distance flight, but also exploit weather patterns for long-distance dispersal. However, little is known about the flight performance of S. mosellana, and the effects of the biotic and abiotic factors that influence its flight activity. In this study, we explored the active flight potential of S. mosellana under various environmental factors using a 26-channel computer-monitored flight mill system. The most suitable temperature for flight and flight distance was 16-24 degrees C; flight duration peaked at 16 degrees C while speed peaked at 28 degrees C. Flight performance gradually declined between 10 and 400 lux light intensity. More than 50% individuals of 1-d-old females flew > 500 m, while only 24% of males flew > 500 m. One-day-old S. mosellana had stronger flight ability than that of 2-d-old individuals. This research showed that S. mosellana possessed strong enough flight ability that they can fly to a high altitude and then disperse via moving air currents. These results can aid in forecasting S. mosellana outbreak.
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Photoswitchable nanoparticles for in vivo cancer chemotherapy.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 11-04-2013
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There are many obstacles to effective cancer chemotherapy, including drug penetration and accumulation in tumors and drug systemic toxicity. The penetration of therapies into tumors is limited by the dense tumor matrix and by compression of the tumor vasculature. We have developed spiropyran-based nanoparticles that shrink from 103 to 49 nm upon irradiation at 365 nm. That shrinkage enhanced tissue penetration and drug release. Irradiation of s.c. HT-1080 tumors in nude mice administered i.v. docetaxel-containing nanoparticles was more effective treatment than free docetaxel or encapsulated docetaxel without irradiation. Irradiation at the tumor site also resulted in less systemic toxicity than if the nanoparticles were irradiated before injection, presumably because of less systemically distributed free drug. The enhanced efficacy of nanoparticles in irradiated tumors may have been related to the observed enhanced tumor penetration by nanoparticles and decompression of tumor blood vessels, which may also increase nanoparticle delivery into tumors.
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[Characteristics of microsomal phase II metabolic enzymes in mouse embryonic stem cell-derived liver tissue].
Zhejiang Da Xue Xue Bao Yi Xue Ban
PUBLISHED: 10-30-2013
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To investigate the characteristics of phase II metabolic enzymes in mouse embryonic stem (ES) cell-derived liver tissue.
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Slow-Injection Ultrasound-Assisted Emulsification-Microextraction for Determination of Phthalate Esters in Water.
J Chromatogr Sci
PUBLISHED: 10-18-2013
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A type of ultrasound-assisted emulsi?cation-microextraction (USAEME) was applied for the extraction and determination of four phthalate esters (e.g., dimethyl phthalate, diethyl phthalate, dibutyl phthalate and benzyl butyl phthalate) in aqueous samples prior to quanti?cation using HPLC-UV. The simultaneous injection of the extraction solvent and ultrasonication of the mixture results in an efficient extraction with the extractant well-dispersed in the sample. The parameters affecting the experimental results were analyzed and optimized through the design of the experiment. Using a central composite face-centered design, the results of 28 experimental data points were analyzed and validated. An optimal set of operating conditions was obtained using 40 ?L of 1,1,2,2-tetrachloroethane and 1% NaCl subjected to 2.0 min of ultrasonication under natural pH. Under optimized conditions, the extractions resulted in analyte recoveries of 75-87% and high enrichment factors of 356-415. The calibration curves were linear, and the correlation coefficients ranged from 0.9992 to 0.9997 at concentrations of 5 to 300 ?g L(-1). The RSDs (n = 5) were 5.6-7.9%. The limits of detection for the four phthalate esters ranged from 0.26 to 1.46 ?g L(-1).
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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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We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

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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.