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51.
Regular hemodialysis treatment induces an elevation in oxidative stress in patients with end‐stage renal failure, resulting in oxidative damage of the most abundant serum protein, albumin. Oxidation of serum albumin causes depletion of albumin reactive thiols, leading to oxidative modification of serum albumin. The aim of this study was to screen the antioxidant capacity of albumins isolated from uremic patients (HD‐ALB) or healthy volunteers (N‐ALB). From high‐performance liquid chromatography spectra, we observed that one uremic solute binds to HD‐ALB via the formation of disulfide bonds between HD‐ALB and the uremic solute. Furthermore, we found using chemiluminescent analysis that the antioxidant capacities for N‐ALB to scavenge reactive oxygen species including singlet oxygen, hypochlorite and hydrogen peroxide were higher than HD‐ALB. Our results suggest that protein‐bound uremic solute binds to albumin via formation of disulfide bonds, resulting in the depletion of albumin reactive thiols. The depletion of albumin reactive thiols leads to a reduced antioxidant capacity of HD‐ALB, implying postmodification of albumin. This situation may reduce the antioxidant capacity of albumin and increase oxidative stress, resulting in increase in complications related to oxidative damage in uremic patients. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
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Plasmonics - Since the metamaterial perfect absorber (MPA) is composed of electromagnetic resonance structures, the main operational mechanism of the MPA is electromagnetic resonance. In this work,...  相似文献   
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A combined pore blockage and cake filtration model was applied to the virus filtration of an Fc-fusion protein using the three commercially available filters, F-1, F-2, and F-3 in a range of buffer conditions including sodium-phosphate and tris-acetate buffers with and without 200 mM NaCl at pH 7.5. The fouling behaviors of the three filters for the feed solutions spiked with minute virus of mice were described well by this combined model for all the solution conditions. This suggests that fouling of the virus filters is dominated by the pore blockage mechanism during the initial stage of the filtration and transformed to the cake filtration mechanism during the later stage of the filtration. Both flux and transmembrane resistance can be described well by this model. The pore blockage rate and the rate of increase of protein layer resistance over blocked pores are found to be affected by membrane properties as well as the solution conditions resulting from the modulation of interactions between virus, protein, and membrane by the solution conditions.  相似文献   
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The hypnotic effect of propofol in the medial preoptic area of the rat   总被引:6,自引:0,他引:6  
Recent introduction of the intravenous anesthetic propofol as an ICU sedative has allowed a deeply sedated state to be maintained for extended periods in the ICU without delays in emergence. Although such sedation has been advocated to promote physiologic sleep, little evidence exists to support such a strategy. To explore propofol's effect on sleep regulation, we administered propofol directly into the medial preoptic area (MPA) of the rat, an anatomic site where administration of other sedatives (triazolam and phenobarbital) also induce sleep. We performed three two-hour sleep studies in the daytime with the lights on following the administration of propofol (8 ng or 40 ng) or vehicle (intralipid). The higher dose of propofol significantly reduced sleep latency and increased nonREM and total sleep times when compared to vehicle. REM sleep times, intermittent waking times and number of transitions were not altered. Mean nonREM sleep bout length was increased significantly at the higher dose. These findings suggest that propofol may enhance sleep by acting at a hypothalamic site.  相似文献   
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The homeodomain is a conserved protein motif that binds to DNA and plays a central role in gene regulation. We use homeodomain as a model system to study the specific interactions between protein and DNA in a complex. Following the fundamental concept of homology modeling, we have developed an algorithm for predicting structures of both protein and DNA using the known structure of a similar complex as the template. The accuracies of the algorithm in predicting the complex structures are evaluated when two of the homeodomain protein-DNA complexes with known structures (antennapedia and MATalpha2) are selected as test systems. This algorithm allows structural studies of homeodomain binds to DNA with different sequences.  相似文献   
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The L1 major capsid protein of human papillomavirus (HPV) type 11, a 55-kDa polypeptide, forms particulate structures resembling native virus with an average particle diameter of 50-60 nm when expressed in the yeast Saccharomyces cerevisiae. We show in this report that these virus-like particles (VLPs) interact with heparin and with cell-surface glycosaminoglycans (GAGs) resembling heparin on keratinocytes and Chinese hamster ovary cells. The binding of VLPs to heparin is shown to exhibit an affinity comparable to that of other identified heparin-binding proteins. Immobilized heparin chromatography and surface plasmon resonance were used to show that this interaction can be specifically inhibited by free heparin and dextran sulfate and that the effectiveness of the inhibitor is related to its molecular weight and charge density. Sequence comparison of nine human L1 types revealed a conserved region of the carboxyl terminus containing clustered basic amino acids that bear resemblance to proposed heparin-binding motifs in unrelated proteins. Specific enzymatic cleavage of this region eliminated binding to both immobilized heparin and human keratinocyte (HaCaT) cells. Removal of heparan sulfate GAGs on keratinocytes by treatment with heparinase or heparitinase resulted in an 80-90% reduction of VLP binding, whereas treatment of cells with laminin, a substrate for alpha6 integrin receptors, provided minimal inhibition. Cells treated with chlorate or substituted beta-D-xylosides, resulting in undersulfation or secretion of GAG chains, also showed a reduced affinity for VLPs. Similarly, binding of VLPs to a Chinese hamster ovary cell mutant deficient in GAG synthesis was shown to be only 10% that observed for wild type cells. This report establishes for the first time that the carboxyl-terminal portion of HPV L1 interacts with heparin, and that this region appears to be crucial for interaction with the cell surface.  相似文献   
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Orthostatic intolerance affects an estimated 1 in 500 persons and causes a wide range of disabilities. After essential hypertension, it is the most frequently encountered dysautonomia, accounting for the majority of patients referred to centers specializing in autonomic disorders. Patients are typically young females with symptoms such as dizziness, visual changes, head and neck discomfort, poor concentration, fatigue, palpitations, tremulousness, anxiety, and, in some cases, syncope. Syncope is the most hazardous symptom of orthostatic intolerance, presumably occurring because of impaired cerebral perfusion and in part to compensatory autonomic mechanisms. The etiology of this syndrome is still unclear but is heterogeneous. Orthostatic intolerance used to be characterized by an overall enhancement of noradrenergic tone at rest in some patients and by a patchy dysautonomia of postganglionic sympathetic fibers with a compensatory cardiac sympathetic activation in others. However, recent advances in molecular genetics are improving our understanding of orthostatic intolerance, such as several genetic diseases (such as Ehler-Danlos syndrome and norepinephrine transporter deficiency) presenting with symptoms typical of orthostatic intolerance. Future work will include investigation of genetic functional mutations underlying interindividual differences in autonomic cardiovascular control, body fluid regulation, and vascular regulation in orthostatic intolerance patients. The goal of this review article is to describe recent advances in understanding the pathophysiological mechanisms of orthostatic intolerance and their clinical significance.  相似文献   
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