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11.
J. Ayrton G.J. Dear W.J. Leavens D.N. Mallett R.S. Plumb 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1998,709(2):6689
Short narrow analytical HPLC columns have been used successfully with high linear flow-rates and combined with mass spectrometric detection to produce a generic approach to quantitative bioanalysis. The approach has been used to validate several assays in the low ng/ml region and an example is given in this paper. When combined with a simple solid-phase extraction process the need for complicated, time consuming method development has been removed for the majority of pharmaceutical compounds. The approach takes advantage of not only the extra selectivity of the MS–MS detector but the excellent resolution and peak shape produced by gradient elution. 相似文献
12.
Paula H Suss Luiz Guilherme A Capriglione Fabiane Barchiki Lye Miyague Danielle Jackowski Letícia Fracaro Andressa V Schittini Alexandra C Senegaglia Carmen LK Rebelatto Márcia Olandoski Alejandro Correa Paulo RS Brofman 《Experimental biology and medicine (Maywood, N.J.)》2015,240(7):969-978
The development of new therapeutic strategies is necessary to reduce the worldwide social and economic impact of cardiovascular disease, which produces high rates of morbidity and mortality. A therapeutic option that has emerged in the last decade is cell therapy. The aim of this study was to compare the effect of transplanting human umbilical cord-derived stromal cells (UCSCs), human umbilical cord blood-derived endothelial cells (UCBECs) or a combination of these two cell types for the treatment of ischemic cardiomyopathy (IC) in a Wistar rat model. IC was induced by left coronary artery ligation, and baseline echocardiography was performed seven days later. Animals with a left ventricular ejection fraction (LVEF) of ≤40% were selected for the study. On the ninth day after IC was induced, the animals were randomized into the following experimental groups: UCSCs, UCBECs, UCSCs plus UCBECs, or vehicle (control). Thirty days after treatment, an echocardiographic analysis was performed, followed by euthanasia. The animals in all of the cell therapy groups, regardless of the cell type transplanted, had less collagen deposition in their heart tissue and demonstrated a significant improvement in myocardial function after IC. Furthermore, there was a trend of increasing numbers of blood vessels in the infarcted area. The median value of LVEF increased by 7.19% to 11.77%, whereas the control group decreased by 0.24%. These results suggest that UCSCs and UCBECs are promising cells for cellular cardiomyoplasty and can be an effective therapy for improving cardiac function following IC. 相似文献
13.
Patients with systemic autoimmune diseases usually produce high levels of antibodies to self-antigens (autoantigens). The
repertoire of common autoantigens is remarkably limited, yet no readily understandable shared thread links these apparently
diverse proteins. Using computer prediction algorithms, we have found that most nuclear systemic autoantigens are predicted
to contain long regions of extreme structural disorder. Such disordered regions would generally make poor B cell epitopes
and are predicted to be under-represented as potential T cell epitopes. Consideration of the potential role of protein disorder
may give novel insights into the possible role of molecular mimicry in the pathogenesis of autoimmunity. The recognition of
extreme autoantigen protein disorder has led us to an explicit model of epitope spreading that explains many of the paradoxical
aspects of autoimmunity – in particular, the difficulty in identifying autoantigen-specific helper T cells that might collaborate
with the B cells activated in systemic autoimmunity. The model also explains the experimentally observed breakdown of major
histocompatibility complex (MHC) class specificity in peptides associated with the MHC II proteins of activated autoimmune
B cells, and sheds light on the selection of particular T cell epitopes in autoimmunity. Finally, the model helps to rationalize
the relative rarity of clinically significant autoimmunity despite the prevalence of low specificity/low avidity autoantibodies
in normal individuals. 相似文献
14.
Wilson ID Nicholson JK Castro-Perez J Granger JH Johnson KA Smith BW Plumb RS 《Journal of proteome research》2005,4(2):591-598
The combination of a new 1.7 mum reversed-phase packing material, and a chromatographic system, operating at ca. 12,000 psi, (so-called ultra performance liquid chromatography, UPLC) has enabled dramatic increases in chromatographic performance to be obtained for complex mixture separation. This increase in performance is manifested in improved peak resolution, together with increased speed and sensitivity. Here, we show that UPLC offers significant advantages over conventional reversed-phase HPLC amounting to a more than doubling of peak capacity, an almost 10-fold increase in speed and a 3- to 5-fold increase in sensitivity compared to that generated with a conventional 3.5 microm stationary phase. The first functional genomic application of UPLC-MS technology is illustrated here with respect to multivariate metabolic profiling of urines from males and females of two groups of phenotypically normal mouse strains (C57BL19J and Alpk:ApfCD) and a "nude mouse" strain. We have also compared this technology to conventional HPLC-MS under similar analytical conditions and show improved phenotypic classification capability of UPLC-MS analysis together with increased ability to probe differential pathway activities between strains as a result of improved analytical sensitivity and resolution. 相似文献
15.
Competing regulation of matrix biosynthesis by mechanical and IGF-1 signalling in elderly human articular cartilage in vitro 总被引:2,自引:0,他引:2
This study investigates the separate and combined effects of IGF-1 and mechanical loads on chondrocytes in elderly human femoral head articular cartilage. Full depth biopsies of articular cartilage were subjected to either no load, static or cyclic (2 s on/2 s off) loading in unconfined compression at a stress of 1 MPa for 48 h with or without IGF-1 (300 ng ml(-1)). Chondrocyte biosynthetic activity was measured using 35S-sulphate and 3H-leucine during the last 24 h of loading. IGF-1 alone increased the rates of isotope incorporation, by 80% for 35S-SO4 and 40% for 3H-leucine, whereas loading alone reduced matrix biosynthesis. Applying load (cyclic or static) in the presence of IGF-1 returned the incorporation rates to their unstimulated levels. This study suggests elderly human articular cartilage is responsive to stimulation by IGF-1 but mechanical factors seem to act sufficiently strongly in the opposite direction to cancel this response. 相似文献
16.
Novel Thermophilic Sulfate-Reducing Bacteria from a Geothermally Active Underground Mine in Japan 总被引:1,自引:0,他引:1 下载免费PDF全文
Anna H. Kaksonen Jason J. Plumb Wendy J. Robertson Stefan Spring Peter Schumann Peter D. Franzmann Jaakko A. Puhakka 《Applied microbiology》2006,72(5):3759-3762
Thermophilic sulfate-reducing bacteria were enriched from samples obtained from a geothermal underground mine in Japan. The enrichment cultures contained bacteria affiliated with the genera Desulfotomaculum, Thermanaeromonas, Thermincola, Thermovenabulum, Moorella, “Natronoanaerobium,” and Clostridium. Two novel thermophilic sulfate-reducing strains, RL50JIII and RL80JIV, affiliated with the genera Desulfotomaculum and Thermanaeromonas, respectively, were isolated. 相似文献
17.
EFFECTS OF HUMAN ACTIVITIES ON STRUCTURE AND COMPOSITION OF WOODY SPECIES OF THE NOKREK BIOSPHERE RESERVE OF MEGHALAYA,NORTHEAST INDIA 下载免费PDF全文
Aims Our study was conducted in the Nokrek Biosphere Reserve (NBR) in the Garo hills districts of Meghalaya, Northeast India. Our aim was to assess the effects of human activities on plant diversity,population structure and regeneration.Methods We selected a representative 1.2 hm2 stand in both the core and buffer zones of NBR. Structure and composition were determined by randomly sampling square quadrats, population structure was assessed by determining age structure, and regeneration was assessed by measuring densities of seedling, sapling and adult trees.Important findings More woody species were recorded from the core zone than the buffer zone (87 vs. 81 species), and there were a large number of tropical, temperate, and Sino-Himalayan, Burma-Malaysian and Malayan elements, primitive families and primitive genera. The trees were distributed in three distinct strata,canopy, subcanopy and sapling. Subcanopy and sapling layers had the highest species richness (81% -88% ). Lauraceae and Euphorbiaceae were the dominant families in terms of the number of species, and a large number of families were represented by single species. Most woody species (57 % - 79 % ) were contagiously distributed and had low frequency ( < 20% ). Although stand density was high in the buffer zone, its basal area was low compared to the stand in the core zone. Low similarity and high β-diversity indicate marked differences in species composition of the stands. Shannon diversity index was high in both the stands, while Simpson dominance index was low. The diameter-class distribution for dominant species revealed that the most had a large number of young individuals in their populations. Preponderance of tree seedlings, followed by a steep decline in population density of saplings and adult trees, indicated that the seedling to sapling stage was the most critical in the life cycle of the tree populations. Most species (42 % - 48 % ) had no regeneration,25 % - 35 % had good/fair regeneration, and the rest had poor regeneration or reoccurred as immigrants. 相似文献
18.
Moraes TJ Martin R Plumb JD Vachon E Cameron CM Danesh A Kelvin DJ Ruf W Downey GP 《American journal of physiology. Lung cellular and molecular physiology》2008,294(2):L368-L377
Proteinases can influence lung inflammation by various mechanisms, including via cleavage and activation of protease-activated receptors (PAR) such as PAR2. In addition, proteinases such as neutrophil and/or Pseudomonas-derived elastase can disarm PAR2 resulting in loss of PAR2 signaling. Currently, the role of PAR2 in host defense against bacterial infection is not known. Using a murine model of acute Pseudomonas aeruginosa pneumonia, we examined differences in the pulmonary inflammatory response between wild-type and PAR2(-/-) mice. Compared with wild-type mice, PAR2(-/-) mice displayed more severe lung inflammation and injury in response to P. aeruginosa infection as indicated by higher bronchoalveolar lavage fluid neutrophil numbers, protein concentration, and TNF-alpha levels. By contrast, IFN-gamma levels were markedly reduced in PAR2(-/-) compared with wild-type mice. Importantly, clearance of P. aeruginosa was diminished in PAR2(-/-) mice. In vitro testing revealed that PAR2(-/-) neutrophils killed significantly less bacteria than wild-type murine neutrophils. Further, both neutrophils and macrophages from PAR2(-/-) mice displayed significantly reduced phagocytic efficiency compared with wild-type phagocytes. Stimulation of PAR2 on macrophages using a PAR2-activating peptide resulted in enhanced phagocytosis directly implicating PAR2 signaling in the phagocytic process. We conclude that genetic deletion of PAR2 is associated with decreased clearance of P. aeruginosa. Our data suggest that a deficiency in IFN-gamma production and impaired bacterial phagocytosis are two potential mechanisms responsible for this defect. 相似文献
19.
20.
Microbial populations associated with treatment of an industrial dye effluent in an anaerobic baffled reactor. 总被引:5,自引:0,他引:5
Fluorescent in situ hybridization (FISH) using 16S and 23S rRNA-targeted probes together with construction of an archaeal 16S ribosomal DNA (rDNA) clone library was used to characterize the microbial populations of an anaerobic baffled reactor successfully treating industrial dye waste. Wastewater produced during the manufacture of food dyes containing several different azo and other dye compounds was decolorized and degraded under sulfidogenic and methanogenic conditions. Use of molecular methods to describe microbial populations showed that a diverse group of Bacteria and Archaea was involved in this treatment process. FISH enumeration showed that members of the gamma subclass of the class Proteobacteria and bacteria in the Cytophaga-Flexibacter-Bacteroides phylum, together with sulfate-reducing bacteria, were prominent members of a mixed bacterial population. A combination of FISH probing and analysis of 98 archaeal 16S rDNA clone inserts revealed that together with the bacterial population, a methanogenic population dominated by Methanosaeta species and containing species of Methanobacterium and Methanospirillum and a relatively unstudied methanogen, Methanomethylovorans hollandica, contributed to successful anaerobic treatment of the industrial waste. We suggest that sulfate reducers, or more accurately sulfidogenic bacteria, together with M. hollandica contribute considerably to the treatment process through metabolism of dye-associated sulfonate groups and subsequent conversion of sulfur compounds to carbon dioxide and methane. 相似文献