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81.
Song Q Naidong W 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2006,830(1):135-142
Bioanalytical methods using liquid/liquid extraction (LLE) and liquid chromatography with electrospray tandem mass spectrometry (LC-MS/MS) are widely used. The organic extracts need to be evaporated and reconstituted, hampering further improvement of throughput and automation. In this study, we demonstrated a novel approach of eliminating these two steps in 96-well LLE by using hydrophilic interaction chromatography with MS/MS (HILIC-MS/MS) on silica column with high organic/low aqueous mobile phase. Omeprazole, its metabolite 5-OH omeprazole, and internal standard desoxyomeprazole, were extracted from 0.05 ml of human plasma using 0.5 ml of ethyl acetate in a 96-well plate. A portion (0.1 ml) of the ethyl acetate extract was diluted with 0.4 ml of acetonitrile and 10 microl was injected onto a Betasil silica column (50 mm x 3.0 mm, 5 microm) and detected by API 3000 and 4000 with (+) ESI. Mobile phase with linear gradient elution consists of acetonitrile, water, and formic acid (from 95:5:0.1 to 73.5:26.5:0.1 in 2 min). The flow rate was 1.5 ml/min with total run time of 2.75 min. The method was validated for a low limit of quantitation at 2.5 ng/ml for both analytes. The method was also validated for specificity, reproducibility, stability and recovery. Lack of adverse matrix effect and carry-over was also demonstrated. The inter-day precision and accuracy of the quality control samples at low, medium and high concentration levels were <4.4% relative standard deviation (R.S.D.) and 4.1% relative error (R.E.) for omeprazole, and 4.5% R.S.D. and 5.6% R.E. for 5-OH omeprazole, respectively. 相似文献
82.
Németh ZH Deitch EA Lu Q Szabó C Haskó G 《American journal of physiology. Cell physiology》2002,283(2):C396-C403
Na+/H+exchanger (NHE) activation has been documented to contribute toendothelial cell injury caused by inflammatory states. However, therole of NHEs in regulation of the endothelial cell inflammatoryresponse has not been investigated. The present study tested thehypothesis that NHEs contribute to endothelial cell inflammationinduced by endotoxin or interleukin (IL)-1. NHE inhibition usingamiloride, 5-(N-ethyl-N-isopropyl)-amiloride, and5-(N-methyl-N-isobutyl)amiloride as well as thenon-amiloride NHE inhibitors cimetidine, clonidine, and harmalinesuppressed endotoxin-induced IL-8 and monocyte chemoattractant protein(MCP)-1 production by human umbilical endothelial vein cells (HUVECs). The suppressive effect of amiloride on endotoxin-induced IL-8 production was associated with a decreased accumulation of IL-8 mRNA.NHE inhibitors suppressed both inhibitory (I)B degradation andnuclear factor (NF)-B DNA binding, suggesting that a decrease inactivation of the IB-NF-B system contributed to the suppression of HUVEC inflammatory response by NHE blockade. NHE inhibition decreased also the IL-1-induced HUVEC inflammatory response, becauseamiloride suppressed IL-1-induced E-selectin expression on HUVECs.These results demonstrate that maximal activation of the HUVECinflammatory response requires a functional NHE. 相似文献
83.
Qi Ye Ming Yan Lin Xu Hou Cao Zhenjiang Li Yong Chen Shuya Li Hanjie Ying 《Biotechnology letters》2009,31(4):537-542
An NADPH-dependent carbonyl reductase (PsCR) gene from Pichia stipitis was cloned. It contains an open reading frame of 849 bp encoding 283 amino acids whose sequence had less than 60% identity
to known reductases that produce ethyl (S)-4-chloro-3-hydroxybutanoates (S-CHBE). When expressed in Escherichia coli, the recombinant PsCR exhibited an activity of 27 U/mg using ethyl 4-chloro-3-oxobutanoate (COBE) as a substrate. Reduction
of COBE to (S)-CHBE by transformants in an aqueous mono-phase system for 18 h, gave a molar yield of 94% and an optical purity of the (S)-isomer of more than 99% enantiomeric excess. 相似文献
84.
Qi Li Yao Zhao Wenke Zhou Zhengyuan Han Rui Fu Fang Lin Dapeng Yu Qing Zhao 《Liver Transplantation》2019,9(46)
The performance of perovskite solar cells (PSCs) relies on the synthesis method and chemical composition of the perovskite materials. So far, PSCs that have adopted two‐step sequential deposited perovskite with the state‐of‐art composition (FAPbI3)1?x(MAPbBr3)x (x < 0.05) have achieved record power conversion efficiency (PCE), while their one‐step antisolvent dripping counterparts with typical composition Cs0.05FA0.81MA0.14Pb(I0.85Br0.15)3 with more bromine have exhibited much better long‐term operational stability. Thus, halogen engineering that aims to elevate bromine content in sequential deposited perovskite film would push operational stability of PSCs toward that of antisolvent dripping deposited perovskite materials. Here, a Br‐rich seeding growth method is devised and perovskite seed solution with high bromine content is introduced into a PbI2 precursor, leading to bromine incorporation in the resulting perovskite film. Photovoltaic devices fabricated by Br‐rich seeding growth method exhibit a PCE of 21.5%, similar to 21.6% for PSCs having lower bromine content. Whereas, the operational stability of PSCs with higher bromine content is significantly enhanced, with over 80% of initial PCE retained after 500 h tracking at maximum power point under 1‐sun illumination. This work highlights the vital importance of halogen composition for the operational stability of PSCs, and introduces an effective way to incorporate bromine into mixed‐cation‐halide perovskite film via sequential deposition method. 相似文献
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87.
ITMSQ: A software tool for N‐ and C‐terminal fragment ion pairs based isobaric tandem mass spectrometry quantification 下载免费PDF全文
Li‐Qi Xie Lei Zhang Ai‐Ying Nie Guo‐Quan Yan Jun Yao Yang Zhang Peng‐Yuan Yang Hao‐Jie Lu 《Proteomics》2015,15(22):3755-3764
Tandem MS (MS2) quantification using the series of N‐ and C‐terminal fragment ion pairs generated from isobaric‐labelled peptides was recently considered an accurate strategy in quantitative proteomics. However, the presence of multiplexed terminal fragment ion in MS2 spectra may reduce the efficiency of peptide identification, resulting in lower identification scores or even incorrect assignments. To address this issue, we developed a quantitative software tool, denoted isobaric tandem MS quantification (ITMSQ), to improve N‐ and C‐terminal fragment ion pairs based isobaric MS2 quantification. A spectrum splitting module was designed to separate the MS2 spectra from different samples, increasing the accuracy of both identification and quantification. ITMSQ offers a convenient interface through which parameters can be changed along with the labelling method, and the result files and all of the intermediate files can be exported. We performed an analysis of in vivo terminal amino acid labelling labelled HeLa samples and found that the numbers of quantified proteins and peptides increased by 13.64 and 27.52% after spectrum splitting, respectively. In conclusion, ITMSQ provides an accurate and reliable quantitative solutionfor N‐ and C‐terminal fragment ion pairs based isobaric MS2 quantitative methods. 相似文献
89.
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目的:构建Survivin启动子调控的表达载体,并检测在启动子调控下HSV-TK自杀基因对肝癌细胞HepG2和正常肝细胞HL-7702凋亡的影响。方法:合成含TK基因的质粒PBI-SUR-TK,利用脂质体Lipofectamine 2000将其导入肝癌细胞和肝细胞。然后分别运用RT-PCR和Western blot特异性检测基因和蛋白的表达情况;利用CCK8方法检测细胞增殖情况,流式细胞仪上机检测细胞凋亡情况。结果:肝癌细胞转染组有更多的TK基因表达产物,增殖情况减弱,凋亡情况明显。结论:Survivin启动子驱动的HSV-TK/GCV自杀基因系统对肝癌可能有一定的治疗作用。 相似文献