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911.
Xiujun Wu Lidong Liu Mengliang Zhang Dan Wu Yingwu Wang Yantong Sun J. Paul Fawcett Jingkai Gu Jiwen Zhang 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2010,878(11-12):861-867
A rapid and sensitive bioassay based on liquid chromatography–tandem mass spectrometry (LC–MS/MS) for the simultaneous determination of four isomeric escin saponins (escin Ia, escin Ib, isoescin Ia and isoescin Ib) in human plasma has been developed and validated. Sample preparation of plasma after addition of telmisartan as internal standard (I.S.) involved solid-phase extraction (SPE) on C18 cartridges. Separation was based on reversed phase chromatography using gradient elution with methanol–acetonitrile (50:50, v/v) and 10 mM ammonium acetate solution (pH 6.8). MS/MS detection in the positive ion mode used multiple reaction monitoring of the transition at m/z 1113.8 → 807.6. Stability issues with the four saponins required the addition of formic acid to plasma samples prior to storage at ?80 °C and analysis within 30 days. The method was linear at concentrations up to 10 ng/mL with correlation coefficients > 0.996 for all analytes. The lower limit of quantitation (LLOQ) for all four saponins was 33 pg/mL. Intra- and inter-day precisions (as relative standard deviation) were all <15% and accuracies (as relative error) in the range ?5.3% to 6.1%. The method was successfully applied to a pharmacokinetic study of escins in healthy volunteers after oral administration of sodium aescinate tablets containing 60 mg escin saponins. 相似文献
912.
Dezhi Kong Sanni Li Xiaowei Zhang Jianmin Gu Man Liu Yan Meng Yan Fu Xiaojin La Gangqiang Xue Lantong Zhang Qiao Wang 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2010,878(29):2989-2996
A simple, sensitive and selective liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for the simultaneous determination of m-nisoldipine and its three metabolites in rat plasma has been developed using nitrendipine as an internal standard (IS). Following liquid–liquid extraction, the analytes were separated using an isocratic mobile phase on a reverse phase C18 column and analyzed by MS in the multiple reaction monitoring (MRM) mode. To avoid contamination by residual sample in the injection syringe, a special injection protocol was developed. We found that m-nisoldipine, metabolite M1 and IS could be ionized under positive or negative electrospray ionization conditions, whereas metabolite M and M2 could only be ionized in the positive mode. The mass spectrometry fragmentation pathways for these analytes are analyzed and discussed herein. The total analysis time required less than 5 min per sample. We employed this method successfully to study the metabolism of m-nisoldipine when it was orally administered to rats at a dose of 9 mg/kg. Three metabolites of m-nisoldipine and an unknown compound of molecular weight 386 were found for the first time in rat plasma. The concentration of the potentially active metabolite was approximately equal to its parent compound concentration. 相似文献
913.
914.
Xiaoen Xu Meng Qiao Yang Zhang Yinghua Jiang Ping Wei Jun Yao Bo Gu Yaqi Wang Jing Lu Zhigang Wang Zhaoqing Tang Yihong Sun Wenshu Wu Qian Shi 《Proteomics》2010,10(7):1374-1390
The proteins involved in breast cancer initiation and progression are still largely elusive. To gain insights into these processes, we conducted quantitative proteomic analyses with 21T series of breast cell lines, which include a normal, primary tumor and a metastatic tumor that were isolated from a single patient. Stable isotope labeling of amino acid in cell culture followed by LC‐MS/MS analysis was performed and deregulated proteins were identified using statistical analysis. Gene ontology analysis revealed that proteins involved in metabolic processes were the most deregulated in both tumorigenesis and metastasis. Interaction network analysis indicated that ERBB2 signaling played a critical role in tumorigenesis. In addition to known markers such as ERBB2 and E‐cadherin, novel markers, including BRP44L, MTHFD2 and TIMM17A, were found to be overexpressed in 21T breast cancer cells and verified in additional breast cell lines. mRNA expression analysis as well as immunohistochemistry analysis in breast cancer tissues indicated that expression level of TIMM17A was directly correlated with tumor progression, and survival analysis suggested that TIMM17A was a powerful prognosis factor in breast cancer. More interestingly, overexpression and siRNA knockdown experiments indicated an oncogenic activity of TIMM17A in breast cancer. Our study provides a list of potential novel markers for breast cancer tumorigenesis and metastasis using a unique cell model. Further studies on TIMM17A as well as other markers on the list may reveal mechanisms that result in more effective therapeutics for cancer treatment. 相似文献
915.
The temples of Angkor monuments including Angkor Thom and Bayon in Cambodia and surrounding countries were exclusively constructed
using sandstone. They are severely threatened by biodeterioration caused by active growth of different microorganisms on the
sandstone surfaces, but knowledge on the microbial community and composition of the biofilms on the sandstone is not available
from this region. This study investigated the microbial community diversity by examining the fresh and old biofilms of the
biodeteriorated bas-relief wall surfaces of the Bayon Temple by analysis of 16S and 18S rRNA gene sequences. The results showed
that the retrieved sequences were clustered in 11 bacterial, 11 eukaryotic and two archaeal divisions with disparate communities
(Acidobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, Proteobacteria; Alveolata, Fungi, Metazoa, Viridiplantae; Crenarchaeote,
and Euyarchaeota). A comparison of the microbial communities between the fresh and old biofilms revealed that the bacterial
community of old biofilm was very similar to the newly formed fresh biofilm in terms of bacterial composition, but the eukaryotic
communities were distinctly different between these two. This information has important implications for understanding the
formation process and development of the microbial diversity on the sandstone surfaces, and furthermore to the relationship
between the extent of biodeterioration and succession of microbial communities on sandstone in tropic region. 相似文献
916.
Adrienn Guóth Dániel Benyó Jolán Csiszár Ágnes Gallé Ferenc Horváth László Cseuz László Erdei Irma Tari 《Acta Physiologiae Plantarum》2010,32(4):719-727
The effects of increasing osmotic stress induced by 100–400 mOsm (−0.976 MPa) polyethylene glycol (PEG 6000) were investigated
in a drought-tolerant (Triticum aestivum L. cv. Mv Emese) and drought-sensitive (cv. GK élet) wheat cultivar at the three-leaf stage. During osmotic stress, the decline
of the water potential (ψ
w) was more significant in the leaves, while the abscisic acid (ABA) levels of the roots increased earlier and remained higher
in the sensitive than in the tolerant variety. There was an increasing gradient of ABA content toward the youngest leaves
in the drought-sensitive GK élet, while more ABA accumulated in the fully developed, older leaves of the tolerant cultivar
Mv Emese. In accordance with the rapid and significant accumulation of ABA, the stomatal conductance decreased earlier in
the tolerant cultivar. The effect of water stress on the PSII photochemistry was pronounced only 1 week after the exposure
to PEG, as indicated by the earlier decrease of the net CO2 fixation, the effective quantum yield (ΦPSII) and the photochemical quenching (q
P) in light-adapted samples of the tolerant variety in 400 mOsm PEG 6000. The stress treatment caused more significant reductions
in these parameters toward the end of the experiment in the sensitive cultivar. In spite of small differences in the photosynthetic
characteristics, the net biomass production was not significantly altered by this osmotic stress. The accumulation of ABA
controlled the distribution of the biomass between the shoot and root systems under osmotic stress, and contributed to the
development of stronger and deeper roots in the drought-sensitive cultivar GK élet. However, the root elongation did not correlate
with the drought sensitivity of these cultivars on the basis of crop yield. 相似文献
917.
XiangYe Kong XingYi Li XiuHong Wang TingTing Liu YingChun Gu Gang Guo Feng Luo Xia Zhao YuQuan Wei ZhiYong Qian 《Carbohydrate polymers》2010,79(1):224
In this paper, a simple and novel method based on free-radical polymerization initiated by potassium persulfate (KPS) was developed to synthesize the MPEG–chitosan diblock copolymer (MPEG–CS). The obtained MPEG–CS diblock copolymer was characterized by Fourier transform infrared (FTIR), 1H nuclear magnetic resonance (1H NMR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC), respectively. The MPEG–CS copolymer could self-assemble into nanoparticles in aqueous solution. A typical TEM photography indicated that the well-spherical nanoparticles with diameter at about 200 nm were obtained. In vitro cell culture assay indicated that MPEG–CS nanoparticles are non-toxic and cell-compatible as the polymer concentration was smaller than 0.6 mg/ml. In conclusion, the obtained MPEG–CS nanoparticles might have great potential application in drug-delivery system. 相似文献
918.
919.
920.
Jian Huang Ding Tang Yi Shen Baoxiang Qin Lilan Hong Aiqing You Ming Li Xin Wang Hengxiu Yu Minghong Gu Zhukuan Cheng 《遗传学报》2010,37(1):23-36
Gibberellin (GA) 2-oxidase plays a key role in the GA catabolic pathway through 2β-hydroxylation.In the present study,we isolated a CaMV 35S-enhancer activation tagged mutant,H032.This mutant exhibited a dominant dwarf and GA-deficient phenotype,with a final stature that was less than half of its wild-type counterpart.The endogenous bioactive GAs are markedly decreased in the H032 mutant,and application of bioactive GAs (GA3 or GA4) can reverse the dwarf phenotype.The integrated T-DNA was detected 12.8 kb upstream of the OsGA2ox6 in the H032 genome by TAIL-PCR.An increased level of OsGA2ox6 mRNA was detected at a high level in the H032 mutant,which might be due to the enhancer role of the CaMV 35S promoter.RNAi and ectopic expression analysis of OsGA2ox6 indicated that the dwarf trait and the decreased levels of bioactive GAs in the H032 mutant were a result of the up-regulation of the OsGA2ox6 gene.BLASTP analysis revealed that OsGA2ox6 belongs to the class III of GA 2-oxidases,which is a novel type of GA2ox that uses C20-GAs (GA12 and/or GA53) as the substrates.Interestingly,we found that a GA biosynthesis inhibitor,paclobutrazol,positively regulated the OsGA2ox6 gene.Unlike the over-expression of OsGA2ox1,which led to a high rate of seed abortion,the H032 mutant retained normal flowering and seed production.These results indicate that OsGA2ox6 mainly affects plant stature,and the dominant dwarf trait of the H032 mutant can be used as an efficient dwarf resource in rice breeding. 相似文献