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151.
Immune response (Ir) genes are linked to the species histocompatibility complex and define as yet uncharacterised phenotypic products which control the immune response to thymus dependent antigens. Antibody formation and antigen induced T lymphocyte proliferation are two examples of immune phenomena which, in vivo and in vitro, operate under Ir gene influence. To clarify their mechanism of action and cellular location, we have examined the contribution of antigen structure (amino acid sequence and conformation to Ir gene control of antigen recognition by T lymphocytes) as well as to the critical role played by the antigen presenting macrophage in expression of that control. We report that immune response gene control of antigen recognition operates at least in part at the level of the macrophage. 相似文献
152.
Summary Using the Fell technique of organ culture of cartilage in a chemically defined medium, it has been shown that prostaglandin A1 at a concentration of 25 g/ml caused chondrocyte death in chick embryonic limb rudiments. An equimolar concentration of PGE2 was not toxic to the cells.Acknowledgments. We are grateful for the support of C. J. K. by the Medical Research Council and of D. L. G. by the Arthritis and Rheumatism Council for Research. Our thanks are due to Dame Honor Fell, F. R. S. for invaluable advice and guidance, to Dr J. Pike (Upjohn Co.) for supplies of prostaglandin A1, and to Dr Sylvia Fitton-Jackson for the gift of culture medium. 相似文献
153.
154.
M. B. Castillo M. D. Gonzalez G. Burton C. P. Lantos A. Roldán 《Cellular and molecular life sciences : CMLS》1983,39(6):617-618
Summary A dissociation between inhibition of RNA synthesis and cell lysis was observed when thymocytes of adrenalectomized rats were incubated with high concentrations of pregn-4-ene-11-ol-3, 20-dione and pregna-1,4-diene-11-ol-3,20-dione. In contrast, no dissociation of these effects was found with the typical glucocorticoids cortisol and corticosterone, nor with their 1,4-diene analogs under the same conditions.Acknowledgments. This work was supported by grants from the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina to the Instituto de Biologia y Medicina Experimental and the Programa de Regulación Hormonal y Metabólica as well as by financial help from the Secretaría de Ciencia y Tecnología. 相似文献
155.
156.
Summary Sodium diethyldithiocarbamate, 2,6-di-tert-butylphenol and N,N-diphenyl-p-phenylenediamine inhibited the generation of medullary prostaglandin E, but 1,2-dimethoxyethane (OH scavenger) and 2,5-dimethylfuran (1O2 scavenger) stimulated basal prostaglandin E production 1.2–1.3-fold. These results suggest that the balance between formation and removal of cellular lipid peroxides sets a peroxide level that can regulate the rate of prostaglandin formation in cells. 相似文献
157.
Summary The flavoprotein ferredoxin reductase catalyzed the oxidation of styrene to styrene oxide in the presence of NADPH. This reaction was inhibited by the addition of catalase and superoxide dismutase. The addition of the nonheme iron protein ferredoxin partially inhibited styrene oxidation. H2O2 was also able to catalyze this reaction when added to the enzyme in the absence of NADPH.Acknowledgments. This work was supported by C.N.R. (National Research Council), Rome, Italy contract No. 79.03197.04. 相似文献
158.
T. Nakajima T. Yasuhara G. Falconieri Erspamer J. Visser 《Cellular and molecular life sciences : CMLS》1979,35(9):1133-1133
Summary Methanol extracts of the skin of the South African amphibians belonging to the genusHeleophryne (H. purcelli purcelli, H. purcelli depressa, H. purcelli orientalis, H. natalensis) contain large amounts (20–500 g/g fresh tissue) of Hyp3-bradykinin.Supported by grants from the Consiglio Nazionale delle Ricerche, Italy, and from the Ministry of Education, Japan. 相似文献
159.
Streptozotocin diabetic rats were infertile as a result of decreased Leydig cell function of the testes. The major changes found were: decreased number of Leydig cells and their spontaneous secretion of testosterone. No change in the receptors to LH on the Leydig cells was observed. LH was found to be obligatory for the regulation of Leydig cell function and fertility. 相似文献
160.
The levels of membrane alkaline phosphatase have been measured on different lymphocyte fractions from human peripheral blood separated on bovine serum albumin discontinuous gradients. The peak in enzyme activity was observed in a non-T-, non-B-cell fraction, rich in "null" lymphocytes; the lowest values were found in the fraction with the highest proportion of T-cells. 相似文献