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排序方式: 共有109条查询结果,搜索用时 31 毫秒
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The epididymis of adult rats metabolizes 3H 5alpha-androstane-3alpah,17beta-diol (3alpha-diol) by experiments in vitro. After incubation of tissue slices at 37 degrees C for 2 hours, 2% of the radioactivity was found in the water-soluble fraction whereas 98% was found to be ether soluble (free steroids). Further investigation of the free steroids showed the following to be present: 3alpha-diol 39.9%, DHT (17beta-hydroxy-5alpha-androstan-3-one) 33.7%, androsterone (3alpha-hydroxy-5alpha-androstan-17-one) 9.2%, 3beta-diol (5alpha-androstane-3beta,17beta-diol) 2.6%, 5alpha-A-dione (5alpha-androstan-3,17-dione) 1.1%, delta 16-3alpha-ol (5alpha-androst-16-en-3alpha-ol) 1.0%, delta16-3beta-ol (5alpha-androst-16-en-3beta-ol) 2.6%, delta 16-3-one (5alpha-androst-16-en-3-one) 2.9%, and polar compounds 3.3%. When segments of the epididymis (caput and cauda) were incubated in the same way, qualitatively similar metabolites were formed but a greater amount of 3alpha-diol was metabolized by the cauda epididymis. This increase was mainly accounted for by an increased formation of delta 16 compounds (14.3% in cauda, 4.3% in caput). This is most probably due to the presence of larger numbers of mature spermatozoa, which, as we have previously shown, form delta16 steroids from 3alpha-diol and DHT (5). 相似文献
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S. Elkahoui Z. Barhoumi N. Djébali W. Djébali W. Chaïbi F. Limam A. Smaoui 《Russian Journal of Plant Physiology》2013,60(2):244-249
Catharanthus roseus (L.) cell response to salinity was investigated. Seven days after cell treatment with 100 mM NaCl, they showed a decrease in dry weight and an increase in sodium and chloride contents (about 12.4- and 1.5-fold, respectively, in comparison to the control). At the ultrastructural level, NaCl treatment reduced cell size and increased plastid density. In addition, it reduced the starch grain size and their number per plastid; however, starch content was 1.5-fold increased, which was due to the increase in the plastid density. At the ultrastructural level, the applied salinity had no obvious effects, such as swelling or disorganization of plastids except a slight decrease in the stroma electron density. Equally, no deleterious effect was observed on mitochondria except a small increase of their crista volume and matrix electron density. It was shown that, although the relative sensitivity of C. roseus cells to salt stress pointed by the reduction in the dry weight, a decrease in the cell size, and the high accumulation of toxic ions, they preserved the integrity of their plastids and mitochondria. 相似文献
5.
Patrick M. Bales Emilija Miljkovic Renke Sarah L. May Yang Shen Daniel C. Nelson 《PloS one》2013,8(6)
In bacterial biofilms, high molecular weight, secreted exopolysaccharides can serve as a scaffold to which additional carbohydrates, proteins, lipids, and nucleic acids adhere, forming the matrix of the developing biofilm. Here we report methods to extract and purify high molecular weight (>15 kDa) exopolysaccharides from biofilms of eight human pathogens, including species of Staphylcococcus, Klebsiella, Acinetobacter, Pseudomonas, and a toxigenic strain of Escherichia coli O157:H7. Glycosyl composition analysis indicated a high total mannose content across all strains with P. aeruginosa and A. baumannii exopolysaccharides comprised of 80–90% mannose, K. pneumoniae and S. epidermidis strains containing 40–50% mannose, and E. coli with ∼10% mannose. Galactose and glucose were also present in all eight strains, usually as the second and third most abundant carbohydrates. N-acetyl-glucosamine and galacturonic acid were found in 6 of 8 strains, while arabinose, fucose, rhamnose, and xylose were found in 5 of 8 strains. For linkage analysis, 33 distinct residue-linkage combinations were detected with the most abundant being mannose-linked moieties, in line with the composition analysis. The exopolysaccharides of two P. aeruginosa strains analyzed were consistent with the Psl carbohydrate, but not Pel or alginate. The S. epidermidis strain had a composition rich in mannose and glucose, which is consistent with the previously described slime associated antigen (SAA) and the extracellular slime substance (ESS), respectively, but no polysaccharide intracellular adhesion (PIA) was detected. The high molecular weight exopolysaccharides from E. coli, K. pneumoniae, and A. baumannii appear to be novel, based on composition and/or ratio analysis of carbohydrates. 相似文献
6.
Inducible nitric oxide synthase activation by interleukin-17 总被引:8,自引:0,他引:8
7.
Wg Richards Sb Van Oss Jn Glickman Lr Chirieac B. Yeap L. Dong Gj Gordon H. Mercer Kk Gill A. Imrich R. Bueno Dj Sugarbaker 《Biotechnic & histochemistry》2007,82(4):189-197
Knowledge of the exact cell content of frozen tissue samples is of growing importance in genomic research. We developed a microaliquoting technique to measure and optimize the cell composition of frozen tumor specimens for molecular studies. Frozen samples of 31 mesothelioma cases were cut in alternating thin and thick sections. Thin sections were stained and evaluated visually. Thick sections, i.e., microaliquots, were annotated using bordering stained sections. A range of cellular heterogeneity was observed among and within samples. Precise annotation of samples was obtained by integration and compared to conventional single face and “front and back” section estimates of cell content. Front and back estimates were more highly correlated with block annotation by microaliquoting than were single face estimates. Both methods yielded discrepant estimates, however, and for some studies may not adequately account for the heterogeneity of mesothelioma or other malignancies with variable cellular composition. High yield and quality RNA was extracted from precision annotated, tumor-enriched subsamples prepared by combining individual microaliquots with the highest tumor cellularity estimates. Microaliquoting provides accurate cell content annotation and permits genomic analysis of enriched subpopulations of cells without fixation or amplification. 相似文献
8.
Ivanovic Nevena Dj Radosavljevic Branimir Zekovic Milica Korcok Davor Ignjatovic Svetlana Djordjevic Brizita Milinkovic Neda 《Biometals》2022,35(2):267-283
BioMetals - This study aimed to investigate the short-term effects of three magnesium (Mg) dietary supplements containing mineral immediately available for absorption on Mg biochemical status... 相似文献
9.
The aim of this study was to investigate the influence of experimental conditions on levothyroxine sodium release from two
immediate-release tablet formulations which narrowly passed the standard requirements for bioequivalence studies. The in vivo study was conducted as randomised, single-dose, two-way cross-over pharmacokinetic study in 24 healthy subjects. The in vitro study was performed using various dissolution media, and obtained dissolution profiles were compared using the similarity
factor value. Drug solubility in different media was also determined. The in vivo results showed narrowly passing bioequivalence. Considering that levothyroxine sodium is classified as Class III drug according
to the Biopharmaceutics Classification System, drug bioavailability will be less sensitive to the variation in its dissolution
characteristics and it can be assumed that the differences observed in vitro in some of investigated media probably do not have significant influence on the absorption process, as long as rapid and
complete dissolution exists. The study results indicate that the current regulatory criteria for the value of similarity factor
in comparative dissolution testing, as well as request for very rapid dissolution (more than 85% of drug dissolved in 15 min),
are very restricted for immediate-release dosage forms containing highly soluble drug substance and need further investigation.
The obtained results also add to the existing debate on the appropriateness of the current bioequivalence standards for levothyroxine
sodium products. 相似文献
10.
Ohlsson C Wallaschofski H Lunetta KL Stolk L Perry JR Koster A Petersen AK Eriksson J Lehtimäki T Huhtaniemi IT Hammond GL Maggio M Coviello AD;EMAS Study Group Ferrucci L Heier M Hofman A Holliday KL Jansson JO Kähönen M Karasik D Karlsson MK Kiel DP Liu Y Ljunggren O Lorentzon M Lyytikäinen LP Meitinger T Mellström D Melzer D Miljkovic I Nauck M Nilsson M Penninx B Pye SR Vasan RS Reincke M Rivadeneira F Tajar A Teumer A Uitterlinden AG Ulloor J Viikari J Völker U Völzke H Wichmann HE Wu TS 《PLoS genetics》2011,7(10):e1002313
Testosterone concentrations in men are associated with cardiovascular morbidity, osteoporosis, and mortality and are affected by age, smoking, and obesity. Because of serum testosterone''s high heritability, we performed a meta-analysis of genome-wide association data in 8,938 men from seven cohorts and followed up the genome-wide significant findings in one in silico (n = 871) and two de novo replication cohorts (n = 4,620) to identify genetic loci significantly associated with serum testosterone concentration in men. All these loci were also associated with low serum testosterone concentration defined as <300 ng/dl. Two single-nucleotide polymorphisms at the sex hormone-binding globulin (SHBG) locus (17p13-p12) were identified as independently associated with serum testosterone concentration (rs12150660, p = 1.2×10−41 and rs6258, p = 2.3×10−22). Subjects with ≥3 risk alleles of these variants had 6.5-fold higher risk of having low serum testosterone than subjects with no risk allele. The rs5934505 polymorphism near FAM9B on the X chromosome was also associated with testosterone concentrations (p = 5.6×10−16). The rs6258 polymorphism in exon 4 of SHBG affected SHBG''s affinity for binding testosterone and the measured free testosterone fraction (p<0.01). Genetic variants in the SHBG locus and on the X chromosome are associated with a substantial variation in testosterone concentrations and increased risk of low testosterone. rs6258 is the first reported SHBG polymorphism, which affects testosterone binding to SHBG and the free testosterone fraction and could therefore influence the calculation of free testosterone using law-of-mass-action equation. 相似文献