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981.
The relationship between gonadal development (histological evidence for spermiogenesis and/or spermatogenesis), sexual behavior (nest-building) and mRNA levels of gonadotropins (betaFSH and betaLH) and growth hormone (GH) in the male pituitary was investigated. Amplification of betaFSH cDNA showed a significantly higher mRNA level in mature males (whether sexually active or not) than in juveniles. However, following PCR amplification of betaLH cDNA, a significantly higher mRNA level was found in the sexually active group compared to the sexually inactive group. These results suggest that FSH may participate in spermatogenesis, whereas LH is more involved in spermiogenesis. The GH mRNA level increased slightly during the maturation process but no significant differences were found between the groups studied. 相似文献
982.
A new class of achiral ligands with atropisomeric conformations has been coordinated to titanium(IV). The ligands are ortho-hydroxy benzamide derivatives which are deprotonated on reaction with titanium tetraisopropoxide to furnish Ti(L)(2)(O-iPr)(2) complexes (L=ortho-phenoxy benzamide). In these octahedral titanium compounds, the ortho-phenoxy benzamide ligands chelate to titanium, bonding through the phenoxide oxygen and the amide carbonyl oxygen. The benzamide ligands adopt atropisomeric conformations with an angle between the aryl and amide groups of approximately 35 degrees. The ligand precursor, ligand, and titanium complexes have been characterized by X-ray crystallography. Only one diastereomer of each titanium complex was observed in the solid state structures. 相似文献
983.
Tomori Z Matis L Karen P Kubínová L Krekule I 《Physiological research / Academia Scientiarum Bohemoslovaca》2000,49(6):695-701
The STESYS2 software is a new version of the IBM PC software supporting interactive stereological measurements. In comparison with the previous STESYS, it is enhanced by a number of useful options, e.g. on-line image input via a TV camera coupled with a microscope operating under MS Windows OS. The main advantage, when compared with other such software packages, is the design of the STESYS2 as a module of the freeware image processing system Image Tool which provides a user-friendly environment including a number of image processing and preprocessing routines. Capabilities of the STESYS2 are illustrated by a practical example: estimation of the surface area of capillaries in the terminal villi of human placenta by the Sandau spatial grid method. 相似文献
984.
Integrin and Cadherin Synergy Regulates Contact Inhibition of Migration and Motile Activity 总被引:16,自引:2,他引:14 下载免费PDF全文
Anna Huttenlocher Margot Lakonishok Melissa Kinder Stanley Wu Tho Truong Karen A. Knudsen Alan F. Horwitz 《The Journal of cell biology》1998,141(2):515-526
Integrin receptors play a central role in cell migration through their roles as adhesive receptors for both other cells and extracellular matrix components. In this study, we demonstrate that integrin and cadherin receptors coordinately regulate contact-mediated inhibition of cell migration. In addition to promoting proliferation (Sastry, S., M. Lakonishok, D. Thomas, J. Muschler, and A. Horwitz. 1996. J. Cell Biol. 133:169–184), ectopic expression of the α5 integrin in cultures of primary quail myoblasts promotes a striking contact-mediated inhibition of cell migration. Myoblasts ectopically expressing α5 integrin (α5 myoblasts) move normally when not in contact, but upon contact, they show inhibition of migration and motile activity (i.e., extension and retraction of membrane protrusions). As a consequence, these cells tend to grow in aggregates and do not migrate to close a wound. This phenotype is also seen with ectopic expression of β1 integrin, paxillin, or activated FAK (CD2 FAK) and therefore appears to result from enhanced integrin-mediated signaling. The contact inhibition observed in the α5 myoblasts is mediated by N-cadherin, whose expression is upregulated more than fivefold. Perturbation studies using low calcium conditions, antibody inhibition, and ectopic expression of wild-type and mutant N-cadherins all implicate N-cadherin in the contact inhibition of migration. Ectopic expression of N-cadherin also produces cells that show inhibited migration upon contact; however, they do not show suppressed motile activity, suggesting that integrins and cadherins coordinately regulate motile activity. These observations have potential importance to normal and pathologic processes during embryonic development and tumor metastasis. 相似文献
985.
986.
Walter E. Horton Jr. Imelda Udo Patricia Precht Richard Blakir Karen Hasty 《In vitro cellular & developmental biology. Animal》1998,34(5):378-384
Summary The objective of this study was to determine if an immortalized mammalian chondrocyte cell line had a profile of matrix metalloproteinase
(MMP) expression that was consistent with what has been reported for primary chondrocytes in vitro and in vivo. A combination of zymography, Western, and Northern analysis was used to examine the expression of MMPs that are relevant
to cartilage degradation. Both interleukin-1β and tumor necrosis factor α induced a 4- to 9-fold increase in the level of
MMP-9 expression in conditioned media, and a 17- to 24-fold increase in MMP-3 mRNA. Other compounds such as basic fibroblast
growth factor and staurosporine each increased MMP-9 expression individually and potentiated the effects of the two cytokines.
Transforming growth factor β had no positive or inhibitory effects. N-methyl arginine blocked the increase in nitric oxide observed following treatment with the cytokines but did not prevent
the increased expression of MMPs. The pattern of metalloproteinase expression observed in IRC cells and the response to cytokines
is very similar to what has been reported during the pathogenesis of osteoarthritis. The IRC cells should be useful as a model
system to study basic mechanisms controlling chondrocyte MMP expression and to identify pharmacological modulators of this
process. 相似文献
987.
988.
Aerobic exercise maintains regional bone mineral density during weight loss in postmenopausal women 总被引:2,自引:0,他引:2
Ryan Alice S.; Nicklas Barbara J.; Dennis Karen E. 《Journal of applied physiology》1998,84(4):1305-1310
This studyexamines the effects of weight loss by caloric restriction (WL) andaerobic exercise plus weight loss (AEx+WL) on total and regional bonemineral density (BMD) in older women. Healthy,postmenopausal women [age 63 ± 1 (SE) yr] not onhormone-replacement therapy underwent 6 mo of WL(n = 15) consisting of dietarycounseling one time per week with a caloric deficit (250-350kcal/day) or AEx+WL (n = 15)consisting of treadmill exercise three times per week in addition tothe weight loss. Maximal aerobic capacity increased only in the AEx+WLgroup (P < 0.001). Body weight,percent fat, and fat mass decreased similarly in both groups(P < 0.005), with no changesin fat-free mass. Total body BMD (by dual-energy X-rayabsorptiometry) decreased in both groups(P < 0.05). Femoral neck, Ward'striangle, and greater trochanter BMD decreased in the WL group(P 0.05) but were not significantlydifferent after AEx+WL.L2-L4BMD did not significantly change in either group. Thus WL andAEx+WL both result in losses of totalbody BMD; however, AEx+WL appears to prevent the loss in regional BMDseen with WL alone in healthy, older women. This suggests that theaddition of exercise to weight-loss programs may reduce the risk forbone loss. 相似文献
989.
White blood cells and their secreted products are key elements of immune systems biology that are important indicators of patient health and disease. We have developed the SurroScan microvolume laser scanning cytometer to immunoprofile hundreds of variables, including cell populations, cell surface antigens, and intracellular molecules in antibody-based assays on small samples (about 1 mL) of whole blood, processed blood, or other fluids without cell purification or washing steps. The system enables high-throughput, robust and automated data capture and analysis. We demonstrate the utility of this immunoprofiling technology platform by surveying patient samples before and after glucocorticosteroid administration and show both the expected and novel response characteristics. This system complements recent advances in genomic and proteomic approaches to disease prediction and monitoring. 相似文献
990.
Sexton KE Barrett S Bridgwood K Carroll M Dettling D Du D Fakhoury S Fedij V Hu LY Kostlan C Pocalyko D Raheja N Smith Y Shanmugasundaram V Wade K 《Bioorganic & medicinal chemistry letters》2011,21(18):5230-5233
A series of pantolactam based compounds were identified as potent antagonists for the androgen receptor (AR). Those that possessed properties suitable for topical delivery were evaluated in the validated Hamster Ear Model. Several compounds were found to be efficacious in reducing wax esters, a major component of sebum, initiating further preclinical work on these compounds. 相似文献