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961.
Cheng H Liu Z Blum W Byrd JC Klisovic R Grever MR Marcucci G Chan KK 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2007,850(1-2):206-212
A specific and sensitive HPLC-MS/MS method for the quantitative determination of valproic acid (VPA) and its metabolite, 2-propyl-4-pentenoic acid in human plasma has been developed, using VPA-d15 as the internal standard. The method was based on pre-column derivatization using 4-dimethylaminobenzylamine dihydrochloride. The derivatives were separated with a gradient elution and quantified by positive electrospray ionization with multiple reaction monitoring. The assay provides routine quantification limits of 200 ng/mL for VPA and 20 ng/mL for 4-ene VPA with within- and between-day coefficients of variation of <10%. This method has been applied to the analysis of plasma samples obtained from patients treated with this drug. 相似文献
962.
963.
Two new guaiane-type sesquiterpene lactones, compounds 1 and 2, along with three known guaianolide- or pseudoguaianolides, were isolated from Centipeda minima (whole plant). Their structures were identified by spectroscopic and mass-spectrometric analyses. The configuration at C5 of the guaiane framework of 1 was rationalized by quantum-mechanical calculations (Table 2). All compounds were found to be active against eight different microbial pathogens (Table 3), with MIC values in the range of 6.25-100 microg/ml. 相似文献
964.
A series of cellular-automata (CA) models have been created, simulating relationships between water (or aqueous solutions) and solid surfaces of differing hydropathic (i.e., hydrophilic or hydrophobic) nature. Both equilibrium- and dynamic-flow models were examined, employing simple breaking and joining rules to simulate the hydropathic interactions. The CA simulations show that water accumulates near hydrophilic surfaces and avoids hydrophobic surfaces, forming concave-up and concave-down meniscuses, resp., under equilibrium conditions. In the dynamic-flow simulations, the flow rate of water was found to increase past a wall surface as the surface became less hydrophilic, reaching a maximum rate when the solid surface was of intermediate hydropathic state, and then declining with further increase in the hydrophobicity of the surface. Solution simulations show that non-polar solutes tend to achieve higher concentrations near hydrophobic-wall surfaces, whereas other hydrophobic/hydrophilic combinations of solutes and surfaces do not show such accumulations. Physical interpretations of the results are presented, as are some possible biological consequences. 相似文献
965.
966.
Roberts A Deming D Paddock CD Cheng A Yount B Vogel L Herman BD Sheahan T Heise M Genrich GL Zaki SR Baric R Subbarao K 《PLoS pathogens》2007,3(1):e5
No single animal model for severe acute respiratory syndrome (SARS) reproduces all aspects of the human disease. Young inbred mice support SARS-coronavirus (SARS-CoV) replication in the respiratory tract and are available in sufficient numbers for statistical evaluation. They are relatively inexpensive and easily accessible, but their use in SARS research is limited because they do not develop illness following infection. Older (12- to 14-mo-old) BALB/c mice develop clinical illness and pneumonitis, but they can be hard to procure, and immune senescence complicates pathogenesis studies. We adapted the SARS-CoV (Urbani strain) by serial passage in the respiratory tract of young BALB/c mice. Fifteen passages resulted in a virus (MA15) that is lethal for mice following intranasal inoculation. Lethality is preceded by rapid and high titer viral replication in lungs, viremia, and dissemination of virus to extrapulmonary sites accompanied by lymphopenia, neutrophilia, and pathological changes in the lungs. Abundant viral antigen is extensively distributed in bronchial epithelial cells and alveolar pneumocytes, and necrotic cellular debris is present in airways and alveoli, with only mild and focal pneumonitis. These observations suggest that mice infected with MA15 die from an overwhelming viral infection with extensive, virally mediated destruction of pneumocytes and ciliated epithelial cells. The MA15 virus has six coding mutations associated with adaptation and increased virulence; when introduced into a recombinant SARS-CoV, these mutations result in a highly virulent and lethal virus (rMA15), duplicating the phenotype of the biologically derived MA15 virus. Intranasal inoculation with MA15 reproduces many aspects of disease seen in severe human cases of SARS. The availability of the MA15 virus will enhance the use of the mouse model for SARS because infection with MA15 causes morbidity, mortality, and pulmonary pathology. This virus will be of value as a stringent challenge in evaluation of the efficacy of vaccines and antivirals. 相似文献
967.
Xiaolin Liao Dan Wang Xiaomu Yu Weitao Li Lei Cheng Jianwei Wang Jingou Tong 《Conservation Genetics》2007,8(4):1003-1007
Rare minnow (Gobiocypris rarus) is an endangered small fish endemic to upper reach of the Yangtze River. From a (GT)n enriched genomic library, 32 microsatellites were isolated and characterized. Nineteen of these loci were polymorphic in
a test population with alleles ranging from 2–7, and observed and expected heterozygosities from zero to 0.8438, and 0.2679
to 0.8264, respectively. In the cross-species amplifications, 13 out of 19 polymorphic loci were found to be also polymorphic
in at least one of the 7 closely related species of the subfamily Gobioninae. These polymorphic microsatellite loci should
provide sufficient level of genetic diversity to evaluate the fine-scale population structure in rare minnow and its closely
related species for the conservation purpose. 相似文献
968.
Mitochondrial DNA (mtDNA) is highly susceptible to oxidative and chemically induced damage, and these insults lead to a number of diseases. In Saccharomyces cerevisiae, the DNA helicase Pif1p is localized to the nucleus and mitochondria. We show that pif1 mutant cells are sensitive to ethidium bromide-induced damage and this mtDNA is prone to fragmentation. We also show that Pif1p associates with mtDNA. In pif1 mutant cells, mtDNA breaks at specific sites that exhibit Pif1-dependent recombination. We conclude that Pif1p participates in the protection from double-stranded (ds) DNA breaks or alternatively in the repair process of dsDNA breaks in mtDNA. 相似文献
969.
Balgley BM Laudeman T Yang L Song T Lee CS 《Molecular & cellular proteomics : MCP》2007,6(9):1599-1608
Peptide identification of tandem mass spectra by a variety of available search algorithms forms the foundation for much of modern day mass spectrometry-based proteomics. Despite the critical importance of proper evaluation and interpretation of the results generated by these algorithms there is still little consistency in their application or understanding of their similarities and differences. A survey was conducted of four tandem mass spectrometry peptide identification search algorithms, including Mascot, Open Mass Spectrometry Search Algorithm, Sequest, and X! Tandem. The same input data, search parameters, and sequence library were used for the searches. Comparisons were based on commonly used scoring methodologies for each algorithm and on the results of a target-decoy approach to sequence library searching. The results indicated that there is little difference in the output of the algorithms so long as consistent scoring procedures are applied. The results showed that some commonly used scoring procedures may lead to excessive false discovery rates. Finally an alternative method for the determination of an optimal cutoff threshold is proposed. 相似文献
970.
Summary Pretarsal orbicularis oculi muscle (POOM) is an important structure of eyelid movement in human. The aim of this study was
to investigate fiber histomorphology and myosin heavy chain (MyHC) isoform composition of adult POOM, and to clarify their
age-related changes. Eyelid specimens from 58 subjects (age range, 21 to 91 years) were collected during upper blepharoplasty
procedures. Serial cross sections of POOM were ATPase-stained and examined under miscroscope. Quantitative measures of muscle
fiber size and fiber type distribution were obtained in 35 subjects with adequate fiber cross sections. Relative MyHC isoform
contents of POOM were retrieved by gel electrophoresis in all 58 subjects. Examination of the histochemical staining revealed
an abundance of type II fiber ( >85%) in human POOM, with more type IIX than IIA fibers. Decreased mean area of all fibers
and type IIA fibers were noted in the old group when compared to the young. As for MyHC analysis, the relative content of
MyHC isoforms exhibited an order of IIX > IIA > I, and the relative MyHC IIA content showed a negative correlation with age.
Comparing with previous studies of limb or masticatory muscles, adult POOM exhibits a unique fiber and MyHC composition, as
well as a different aging pattern. 相似文献