bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fibronectin‐based isolation of valve interstitial cell subpopulations: Relevance to valve disease
Authors: Stephens Elizabeth H. , Huynh Thanh N. , Cieluch Jennifer D. , Grande‐Allen K. Jane 
Published: February 2009

AbstractMyxomatous mitral valves (MVs) contain elevated proportions of unique cell populations such as myofibroblasts. Without a reliable technique to isolate such cell populations, however, it has been difficult to study the role of these cells. The goal of this study was to use fibronectin (FN) to isolate distinct cell subpopulations from normal porcine MVs. Cells from porcine posterior MV leaflets were separated based on time‐dependent adhesion to either tissue culture plastic (TCP) flasks or FN‐coated flasks. The resultant “FAST” and “SLOW” adhering subpopulations from each technique were phenotyped using flow cytometry and immunocytochemistry to detect expression of myofibroblast markers, enzymes for collagen synthesis, and MAP kinases. Compared with FN SLOW, FN FAST showed significantly higher expression of prolyl 4‐hydroxylase, heat shock protein‐47 (HSP47), smooth muscle alpha‐actin (SMαA), nonmuscle myosin (Smem), extracellular‐related signaling kinase (ERK) 1, ERK2, and phosphorylated‐ERK. In contrast, TCP FAST showed higher expression of only HSP47, SMαA, and Smem compared with TCP SLOW. In conclusion, differential adhesion to FN successfully separated a myofibroblast‐like subpopulation from the posterior leaflet of the MV. This subpopulation may be useful in studying myxomatous MV disease, although additional studies remain to verify that this myofibroblast‐like population resembles that observed in myxomatous MV disease. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Concentration dependent dual effect of thrombin in endothelial cells via Par‐1 and Pi3 Kinase
Authors: Bae Jong‐Sup , Kim Yong‐ung , Park Moon‐Ki , Rezaie Alireza R. 
Published: February 2009

AbstractDisruption of endothelial barrier is a critical pathophysiological factor in inflammation. Thrombin exerts a variety of cellular effects including inflammation and apoptosis through activation of the protease activated receptors (PARs). The activation of PAR‐1 by thrombin is known to have a bimodal effect in endothelial cell permeability with a low concentration (pM levels) eliciting a barrier protective and a high concentration (nM levels) eliciting a barrier disruptive response. It is not known whether this PAR‐1‐dependent activity of thrombin is a unique phenomenon specific for the in vitro assay or it is part of a general anti‐inflammatory effect of low concentrations of thrombin that may have a physiological relevance. Here, we report that low concentrations of thrombin or of PAR‐1 agonist peptide induced significant anti‐inflammatory activities. However, relatively high concentration of thrombin or of PAR‐1 agonist peptide showed pro‐inflammatory activities. By using function‐blocking anti‐PAR‐1 antibodies and PI3 kinase inhibitor, we show that the direct anti‐inflammatory effects of low concentrations of thrombin are dependent on the activation of PAR‐1 and PI3 kinase. These results suggest a role for cross communication between PAR‐1 activation and PI3 kinase pathway in mediating the cytoprotective effects of low concentrations of thrombin in the cytokine‐stimulated endothelial cells. J. Cell. Physiol. 219: 744–751, 2009. © 2009 Wiley‐Liss, Inc.
Advances in transmission electron microscopy: In situ straining and in situ compression experiments on metallic glasses
Authors: De Hosson Jeff Th.M. 
Published: February 2009

AbstractIn the field of transmission electron microscopy (TEM), fundamental and practical reasons still remain that hamper a straightforward correlation between microscopic structural information and deformation mechanisms in materials. In this article, it is argued that one should focus in particular on in situ rather than on postmortem observations of the microstructure. This viewpoint has been exemplified with in situ straining and in situ compression studies on metallic glasses. In situ TEM straining of amorphous metals permits an evaluation of the thickness of the liquid‐like layer (LLL) formed because of heat evolution after shear band development. The experimental evaluation confirms that the thickness of a LLL present at the last moment of fracture substantially exceeds the generally accepted thickness of a shear band. In situ TEM and in situ SEM compression experiments on metallic glass pillars lead to the conclusion that smaller sized pillars deform more homogeneously than larger sized pillars. Microsc. Res. Tech., 2009. © 2009 Wiley‐Liss, Inc.
Combining in situ transmission electron microscopy and molecular dynamics computer simulations to reveal the interaction mechanisms of dislocations with stacking‐fault tetrahedron in nuclear materials
Authors: Matsukawa Yoshitaka , Briceno Martha , Robertson Ian M. 
Published: February 2009

AbstractIn situ straining experiments conducted in a transmission electron microscope have been performed to reveal how dislocations interact with and annihilate isolated stacking‐fault tetrahedra, common defect clusters in irradiated face‐centered cubic metals. Comparison of the experimental results with the predictions from molecular dynamics computer simulations shows some similarities and some striking differences. The comparison suggests challenges for the simulations and demonstrates how, despite the disparity in operational parameters, the simulations can be used to interpret experimental results. Microsc. Res. Tech., 2009. © 2009 Wiley‐Liss, Inc.
Changes in the GST activity of the mussel Mytilus galloprovincialis during exposure and depuration of microcystins
Authors: Fernandes Sandra , Welker Martin , Vasconcelos Vitor Manuel 
Published: February 2009

AbstractMussels are quite resistant to cyanotoxins and their resistance may be because of an efficient metabolization of cyanotoxins by glutathione‐S‐transferases (GST) activity. Nevertheless, other secondary metabolites may interfere with the detoxication efficiency. The accumulation and depuration of hepatotoxins produced by the freshwater cyanobacterium Microcystis aeruginosa in the mussel Mytilus galloprovincialis were studied. Mussels were fed twice a day 1.5×105 cells/mL of the toxic cyanobacterium, which produces microcystins (MCs) ‐FR, ‐LR and ‐WR, for 4 days. After that period, the animals were placed in toxin‐free water and were fed the green algae Ankistrodesmus sp. During 2 weeks, the concentration of the toxin in the mussels was monitored using an ELISA assay. Mussels showed a maximum detectable level of MCs of 0.38 µg/g mussels dry weight (DW) during the accumulation period and 0.37 µg MC/g mussel DW by day 4 of the depuration period. Then there was a decrease trend with peaks of toxin at days 8 and 12 of the depuration period. The activity of the detoxication enzymes GST was studied and the results showed that the peaks of toxin in the mussels coincide with an increase in the activity of GST. These results support the hypothesis that the rise of the toxin level on days 4, 8 and 12 of the depuration period in the mussels may be related to the renewal of protein phosphatases and subsequent release of unbound toxins. J. Exp. Zool. 311A:226–230, 2009. © 2009 Wiley‐Liss, Inc.
Reduction of liver tumor necrosis factor‐α expression by targeting delivery of antisense oligonucleotides into Kupffer cells protects rats from fulminant hepatitis
Authors: Dong Lei , Zuo Longsheng , Xia Suhua , Gao Shuying , Zhang Chenyu , Chen Jiangning , Zhang Junfeng 
Published: February 2009

AbstractBackgroundFulminant liver failure can cause extreme mortality due to the lack of effective and targeting therapeutics for the disease. Novel therapeutics using antisense technology require an efficient and safe delivery system with Kupffer cell targeting ability.MethodsWe explored the capacity of galactosylated low molecular weight chitosan (GLC) to efficiently mediate the antisense oligonucleotide (ASO) TJU‐2755 into Kupffer cells, enhance the effect of the oligonucleotides on the suppression of tumor necrosis factor (TNF)‐α and prolong the active time of the antisense drug in vivo. The protective and therapeutic effect of ASO/GLC in the animal model of D‐galactosamine/lipopolysaccharide‐induced fulminant hepatitis was tested.ResultsASOs delivered by GLC were concentrated in Kupffer cells and more potent in reducing the expression of TNF‐α mRNA, as well as reducing serum TNF‐α levels. Furthermore, the ASO/GLC complex successfully rescued animals from fulminant hepatitis and mortality. Compared to naked ASO, the complex notably reduced the dose administrated in animals and prolonged its effectiveness. A single dose of 5 mg ASO per kg body weight achieved a satisfactory effect after 5 days, and 20 mg ASO per kg body weight preserved 70% of the effect after more than 2 weeks. Its efficacy was affirmed through both pretreatment and therapeutic use after liver damage had begun.ConclusionsInhibiting TNF‐α expression in the liver by this strategy represents a novel therapeutic approach that may be valuable for the treatment of some inflammation‐related liver diseases. Copyright © 2009 John Wiley & Sons, Ltd.
Adenoviral delivery of dominant‐negative transforming growth factor β type II receptor up‐regulates transcriptional repressor SKI‐like oncogene, decreases matrix metalloproteinase 2 in hepatic stellate cell and prevents liver fibrosis in rats
Authors: Marquez‐Aguirre Ana , Sandoval‐Rodriguez Ana , Gonzalez‐Cuevas Jaime , Bueno‐ Topete Miriam , Navarro‐Partida Jose , Arellano‐Olivera Immaculada , Lucano‐Landeros Silvia , Armendariz‐Borunda Juan 
Published: February 2009

AbstractBackgroundDominant‐negative transforming growth factor β type II receptor (TβRIIΔcyt) is a protein that blocks transforming growth factor (TGF‐β) signaling. Because the consequences of blocking TGF‐β have not been completely elucidated in liver fibrosis, we analysed the effects of adenoviral delivery of TβRIIΔcyt on profibrogenic genes and matrix metalloproteinase (MMP) proteins, as well as on TGF‐β signal repressor SKI‐like oncogene (SnoN), in cultured hepatic stellate cells (HSCs) and in a rat model of liver fibrosis.MethodsTo induce liver fibrosis, rats were treated with thioacetamide for 7 weeks and administrated once with Ad‐TβRIIΔcyt or Ad‐βgal through the iliac vein. Fibrosis was measured by morphometric analysis. We evaluated SnoN by western blot, immunocytochemistry and immunohistochemistry; MMP activity was determined by zymography and profibrogenic gene expression by the real‐time reverse transcriptase‐polymerase chain reaction in cultured HSCs and liver tissue.ResultsProfibrogenic gene expression of collagen α1 (I), TGF‐β1, platelet‐derived growth factor‐B, plasminogen activator inhibitor (PAI)‐1, tissue inhibitor of matrix metalloproteinase‐1 and MMP‐2 was down‐regulated; whereas MMP‐3 was over‐expressed in response to Ad‐TβRIIΔcyt in HSCs. Moreover, zymography assays corroborated MMP‐2 and MMP‐3 changes in activity. Surprisingly, anti‐TGF‐β molecular intervention increased nuclear SnoN in HSCs. In vivo, Ad‐TβRIIΔcyt reduced liver fibrosis, increased nuclear SnoN in sinusoidal cells, and also produced significant suppression in collagen α1 (I), TGF‐β1, PAI‐1, MMP‐2 and over‐expression in MMP‐3 in thioacetamide‐intoxicated animals.ConclusionsThe results obtained in the present study suggest that the molecular mechanism for the blocking effects of Ad‐TβRIIΔcyt in TGF‐β signaling acts via up‐regulation of the transcriptional repressor SnoN, which antagonizes TGF‐β signaling (TGF‐β/Smad‐pathway inhibitor). Consequently, profibrogenic genes are down‐regulated. Copyright © 2009 John Wiley & Sons, Ltd.
The Max homodimeric b‐HLH‐LZ significantly interferes with the specific heterodimerization between the c‐Myc and Max b‐HLH‐LZ in absence of DNA: a quantitative analysis
Authors: McDuff François‐Olivier , Naud Jean‐François , Montagne Martin , Sauvé Simon , Lavigne Pierre 
Published: February 2009

AbstractSpecific heterodimerization plays a crucial role in the regulation of the biology of the cell. For example, the specific heterodimerization between the b‐HLH‐LZ transcription factors c‐Myc and Max is a prerequisite for c‐Myc transcriptional activity that leads to cell growth, proliferation and tumorigenesis. On the other hand, the Mad proteins can compete with c‐Myc for Max. The Mad/Max heterodimer antagonizes the effect of the c‐Myc/Max heterodimer. In this contribution, we have focused on the specific heterodimerization between the b‐HLH‐LZ domains of c‐Myc and Max using CD and NMR. While the c‐Myc and Max b‐HLH‐LZ domains are found to preferentially form a heterodimer; we demonstrate for the first time that a significant population of the Max homodimeric b‐HLH‐LZ can also form and hence interferes significantly with the specific heterodimerization. This indicates that the Max/Max homodimer can also interfere with c‐Myc/Max functions, therefore adding to the complexity of the regulation of transcription by the Myc/Max/Mad network. The demonstration of the existence of the homodimeric population was made possible by the application of numerical routines that enable the simulation of composite spectroscopic signal (e.g. CD) as a function of temperature and total concentration of proteins. From a systems biology perspective, our routines may be of general interest as they offer the opportunity to treat many competing equilibriums in order to predict the probability of existence of protein complexes. Copyright © 2009 John Wiley & Sons, Ltd.
Spatial variation of intestinal skatole production and microbial community in Jinhua and Landrace pigs
Authors: Li Cai‐Yan , Wu Chao , Liu Jian‐Xin , Wang Yi‐Zhen , Wang Jia‐Kun 
Published: February 2009

AbstractBACKGROUND: An excessive accumulation of skatole in pigs is a major contributor to boar taint. Intestinal skatole concentrations may vary among different pig segments and breeds. The objective of this study was to evaluate the spatial variation of intestinal skatole production and the microbial community in local Jinhua and exotic Landrace pigs.RESULTS: For both breeds, skatole concentration increased towards the rectum and segment had a significant effect on skatole (P < 0.001). The caecal skatole concentration in Landrace was significantly lower than proximal, distal colonic and rectal skatole levels (P < 0.05). Compared with Jinhua pigs, the rectal skatole and proximal and distal colonic indole levels were significantly higher in Landrace pigs (P < 0.05). Volatile fatty acids were significantly affected by breed except for isobutyrate and isovalerate (P < 0.05), with higher butyrate level and lower pH in Landrace pigs (P < 0.05). There were no significant differences in mitosis and apoptosis for the two breeds. The denaturing gradient gel electrophoresis profile showed differences between breeds and segments within one breed, though some bands were common to all samples.CONCLUSION: The higher skatole levels in Landrace pigs may be not associated with higher intestinal apoptosis. The results suggested that pig genotype plays a role in the establishment of the host‐specific microbiota and that the variations in fermentation patterns are more likely to explain differences in intestinal skatole production. Copyright © 2009 Society of Chemical Industry
Implications of spatial and temporal changes in concentration of pyruvate and glucose in onion (Allium cepa L.) bulbs during controlled atmosphere storage
Authors: Abayomi Louise A , Terry Leon A 
Published: February 2009

AbstractBACKGROUND: Pungency and perceived sweetness are important quality assurance parameters for onion producers; however, there is still a paucity of information describing the spatial changes within the bulb of some taste‐related compounds during storage. Accordingly, onion bulbs of cultivars (cvs.), SS1 (low pungency, low dry matter) and Renate (pungent, high dry matter) bulbs, were divided into 12 sections and both spatial and temporal variations of pyruvate and glucose were recorded during standard controlled atmosphere storage.RESULTS: Pyruvate within cv. SS1 bulbs reached 8.3 µmol g−1 fresh weight (FW) from pre‐storage levels of less than 3.4 µmol g−1 FW, whilst pyruvate changes in cv. Renate remained in the ‘pungent’ category, between 12 µmol g−1 FW and 15 µmol g−1 FW; thus having fewer implications for marketing and quality assurance. Glucose concentrations were significantly higher for both cvs. in the neck region as compared to basal tissue. Higher glucose levels were recorded in the core of the bulb than in outer scales of cv. Renate. The opposite was found for cv. SS1. There was an inverse correlation of − 0.69 and − 0.87 between glucose and pyruvate for cvs. SS1 and Renate, respectively.CONCLUSION: In order to measure overall bulb flavour, it is recommended that sampling procedures, particularly for routine pungency determination, be carried out on bulb quarters or wedges rather than equatorial sections. Copyright © 2009 Society of Chemical Industry
Structure elucidation of three diphenyl ether derivatives from the mangrove endophytic fungus SBE‐14 from the South China Sea
Authors: Liu Fan , Li Qing , Yang Hong , Cai Xiao‐Ling , Xia Xue‐Kui , Chen Sheng‐Ping , Li Meng‐Feng , She Zhi‐Gang , Lin Yong‐Cheng 
Published: February 2009

AbstractTwo new natural products, tenelate A (1) and B (2), together with the known compound, tenellic acid C (3), were isolated from the mangrove endophytic fungus Talaromyces sp. (SBE‐14), from the South China Sea. Their structures were elucidated by spectroscopic methods, mainly 1D and 2D NMR techniques. Copyright © 2009 John Wiley & Sons, Ltd.
Fast acquisition scheme for achieving high‐resolution MRS with J‐scaling under inhomogeneous fields
Authors: Chen Xi , Lin Meijin , Chen Zhong , Zhong Jianhui 
Published: February 2009

AbstractIntermolecular multiple‐quantum coherences (iMQCs) can refocus the phase dispersion caused by magnetic field inhomogeneities while preserving the chemical shift, so they have been applied to achieve high‐resolution MR spectroscopy free of line broadening caused by susceptibility gradients. However, previous iMQC high‐resolution methods all require two‐dimensional spectra sampling of the full range of chemical shifts of solute evolutions in both F1 and F2 dimensions, resulting in a prolonged scanning time for data acquisition. In this work, sparse sampling in the t1 dimension and subsequent fold‐over correction are used to speed up the intermolecular zero‐quantum coherence spectroscopy by up to 50 times on high‐field MR systems. Furthermore, three types of spectra with homo‐decoupling, original J‐coupling constants, and doubled J‐coupling constants respectively are obtained with manipulation of the t1 period. The water suppression is also improved by the combined use of intermolecular double‐quantum filter and excitation sculpting. The feasibilities of this group of new sequences are demonstrated by experiments using an agar gel phantom with an air bubble, in vitro pig brain tissues and an intact postmortem mudskipper. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Postmortem MRI of human brain hemispheres: T2 relaxation times during formaldehyde fixation
Authors: Dawe Robert J. , Bennett David A. , Schneider Julie A. , Vasireddi Sunil K. , Arfanakis Konstantinos 
Published: February 2009

AbstractUnlike in vivo imaging, postmortem MRI allows for invasive examination of the tissue specimen immediately after the MR scan. However, natural tissue decomposition and chemical fixation cause the postmortem tissue's MRI properties to be different from those found in vivo. Moreover, these properties change as postmortem fixation time elapses. The goal of this study was to characterize the T2 relaxation changes that occur over time in cadaveric human brain hemispheres during fixation. Five hemispheres immersed in formaldehyde solution were scanned on a weekly basis for 3 months postmortem, and once again at 6 months postmortem. The T2 relaxation times were measured throughout the hemispheres. Over time, T2 values near the edges of the hemispheres decreased rapidly after death, while T2 values of deep tissue decreased more slowly. This difference is likely due to the relatively large distance from the hemisphere surface, and other barriers limiting diffusion of formaldehyde molecules to deep tissues. In addition, T2 values in deep tissue did not continuously decay to a plateau, but instead reached a minimum and then increased to a plateau. This final increase may be due to the effects of prolonged tissue decomposition, a hypothesis that is supported by numerical simulations of the fixation process. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Multicomponent T2 relaxation analysis in cartilage
Authors: Reiter David A. , Lin Ping‐Chang , Fishbein Kenneth W. , Spencer Richard G. 
Published: February 2009

AbstractMR techniques are sensitive to the early stages of osteoarthritis, characterized by disruption of collagen and loss of proteoglycan (PG), but are of limited specificity. Here, water compartments in normal and trypsin‐degraded bovine nasal cartilage were identified using a nonnegative least squares multiexponential analysis of T2 relaxation. Three components were detected: T2,1 = 2.3 ms, T2,2 = 25.2 ms, and T2,3 = 96.3 ms, with fractions w1 = 6.2%, w2 = 14.5%, and w3 = 79.3%, respectively. Trypsinization resulted in increased (P < 0.01) values of T2,2 = 64.2 ms and T2,3 = 149.4 ms, supporting their assignment to water compartments that are bound and loosely associated with PG, respectively. The T2 of the rapidly relaxing component was not altered by digestion, supporting assignment to relatively immobile collagen‐bound water. Relaxation data were simulated for a range of TE, number of echoes, and SNR to guide selection of acquisition parameters and assess the accuracy and precision of experimental results. Based on this, the expected experimental accuracy of measured T2s and associated weights was within 2% and 4% respectively, with precision within 1% and 3%. These results demonstrate the potential of multiexponential T2 analysis to increase the specificity of MR characterization of cartilage. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
High‐order doubly asymptotic open boundaries for scalar wave equation
Authors: Prempramote Suriyon , Song Chongmin , Tin‐Loi Francis , Lin Gao 
Published: February 2009

AbstractHigh‐order doubly asymptotic open boundaries are developed for transient analyses of scalar waves propagating in a semi‐infinite layer with a constant depth and a circular cavity in a full‐plane. The open boundaries are derived in the frequency domain as doubly asymptotic continued fraction solutions of the dynamic stiffness of the unbounded domains. Each term of the continued fraction is a linear function of the excitation frequency. The constants of the continued fraction solutions are determined recursively. The continued fraction solution is expressed in the time domain as ordinary differential equations, which can be solved by standard time‐stepping schemes. No parameters other than the orders of the low‐ and high‐frequency expansions need to be selected by users. Numerical experiments demonstrate that evanescent waves and long‐time (low‐frequency) responses are simulated accurately. In comparison with singly asymptotic open boundaries, significant gain in accuracy is achieved at no additional computational cost. Copyright © 2009 John Wiley & Sons, Ltd.