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Flavodoxin. Chemical and biological properties   总被引:3,自引:0,他引:3  
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Dose-dependent hypertrichosis is a common dermatological side-effect affecting the majority of patients treated with cyclosporine A (CSA). Previous studies have not demonstrated the influence of CSA on specific sex hormone levels. The aim of this study is to investigate whether CSA increases the activity of 5 alpha-reductase, an enzyme which transforms androgens into dihydrotestosterone in peripheral tissues. The metabolite which best reflects this activity is 5 alpha-androstane-3 alpha,17 beta-diol glucuronide (Adiol G). The study was carried out on 49 insulin-dependent diabetes patients participating in the double-blind "Cyclosporine-Diabète-France" clinical trial, of which 28 were treated with CSA (16 males and 12 females), and 21 received only placebo (10 males and 11 females). All patients underwent extensive clinical and laboratory evaluations prior to and during the present study. In addition to Adiol G, testosterone (T), dehydroepiandrosterone sulfate (DHEA S) and sex hormone-binding globulin (SHBG) were assayed. Levels of Adiol G increased significantly in CSA-treated groups: males, 11.86 +/- 2.58 vs 7.83 +/- 2.30 nmol/l; females, 4.48 +/- 2.70 vs 2.10 +/- 1.22 nmol/l; P less than 0.02 (comparison of means). There were no significant differences in this parameter before and during treatment in either the male or female placebo groups (paired t-test). During the treatment period, T, DHEA S, SHBG and the T/SHBG ratio did not significantly change with respect to their baseline values in any of the groups studied (comparison of means). Comparison (using paired t-test) showed a significant increase of DHEA S in CSA-treated groups: males, delta = 3.08 +/- 3.33 nmol/l, P less than 0.01; females, delta = 0.98 +/- 1.13 nmol/l, P less than 0.05. In conclusion, it is possible that CSA induces hypertrichosis or hirsutism by increasing 5 alpha-reductase activity in peripheral tissues. Nevertheless the role of increased DHEA S as a possible Adiol G precursor cannot be excluded.  相似文献   
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The integrins are a class of adhesion molecules which have been implicated in the homing of hemopoietic stem cells and in their restriction within the bone marrow. Integrins function as mediators of cell-extracellular matrix (ECM) interactions and also of cell-cell interactions. They are unique membrane receptors which are capable of activation, change in affinity, and change in expression. Because of their broad potential for modulation we examined the effect of a cytokine growth factor which is present constitutively in the marrow, interleukin 3 (IL3), on integrin-mediated adherence of hemopoietic progenitor cells to the matrix component fibronectin (FN). The multipotential murine cell line B6Sut and the committed granulocyte progenitor cell line FDCP-1 were used. Both of these cell lines have been shown to bind to FN-coated dishes and to dishes coated with the 120 kDa and 40 kDa chymotryptic fragments of FN. It was found that after a brief withdrawal of IL3 the cells lost 80% adherence to the 120 kDa FN fragment containing the RGD cell binding site. This loss of binding was not related to a loss of viability, appeared unrelated to the growth/survival activity of IL3, and was quickly reversible by readdition of the growth factor. Adhesion of these cells to the RGD site was likely mediated by α5b?1 integrin which was identified in the cell membrane of both cell lines, but present in low copy number in B6Sut cells. Two antibodies against the external and internal domains of α5 and one antibody against b?1 were used to study expression of the integrin. By flow cytometry the expression of α5 was found to decrease in both cell lines by 4 h in the absence of IL3. The relative mean fluorescence intensity for B6Sut cells decreased from 1.0 (control cells always in the presence of IL3) to 0.6 over 4 h, and for FDCP-1 cells the decrement was from 1.0 to 0.8. The loss of RGD-mediated adhesion in the absence of IL3 appeared to proceed through this decrement in expression of the integrin; a loss of affinity of the receptor for its substrate was not detected. The general modulation of integrin activity by growth factors is of great interest because of its potential negative impact on the endothelium in cytokine-treated patients, and also because of its potential positive impact on engraftment during clinical bone marrow transplantation. © 1995 Wiley-Liss, Inc.  相似文献   
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