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201.
202.
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
203.
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
204.
S. Y. Dike Meera Kamath J. R. Merchant 《Cellular and molecular life sciences : CMLS》1977,33(8):985-985
Summary A one-step synthesis of hexahydrocannabinoid analogs (HHC) is described making use of the condensation of phenolic ketones and aldehydes with citronellal in the presence of pyridine.Grateful thanks are accorded to Drs L. Chopard and S. Selvavinayakam for spectral measurements and Dr I. Fleming for useful discussion.R. Mechoulam and Y. Gaoni, Recent advances in the chemistry of Hashish, in: Progress in the Chemistry of Organic natural products, vol. 25, p. 175. Ed. L. Zechmeister. Springer Verlag, Wien 1967; R. Mechoulam, Marijuana Chemistry and Pharmacology, metabolism and clinical effects. Academic Press, New York 1973; R. Mechoulam, N. K. McCallum and S. Burstein, Chem. Rev.76, 75 (1976). 相似文献
205.
Immunoglobulin diversity seems to arise largely by three mechanisms: (1) the existence of several germ-line genes, which must be rearranged before expression--that is, V and J for the light (L) chains, V, D and J for the heavy (H) chains; (2) somatic events, including mutations and gene conversion; and (3) combinatorial association of heavy and light chains, leading to the proposal that random pairing of p X H and q X L chains might generate p X q antibody molecules expressing discrete specificities. As heavy and light chains derived from the same immunoglobulin molecule would frequently reassociate preferentially, it is likely that only a fraction of potential heavy--light pairs actually provides "valid' antibodies. As a consequence of combinatorial heavy--light chain pairing, antibodies of discrete specificities sharing the same VH region, associated with distinct light chains (or vice versa) should be encountered. We report here that two heavy chains, derived from the same VH germ-line gene, may be present in anti-NP or anti--GAT antibodies, depending on their association with a specific lambda or kappa light chain, respectively. 相似文献
206.
207.
Summary Daily evening injections of isoproterenol extended the period of high pineal N-acetyltransferase activity and retarded the growth of testes, seminal vesicles and prostate in rats treated neonatally with testosterone propionate.The authors are grateful to Mrs Marie Svobodová for her skillful technical assistance. 相似文献
208.
J. J. Cazzulo Berta M. Franke de Cazzulo 《Cellular and molecular life sciences : CMLS》1982,38(11):1335-1337
Summary Cell-free extracts ofTrypanosoma cruzi contain proteolytic activity able to degrade endogenous substrates. The activity was maximal at pH 3 to 4, had an optimal temperature of 65°C, and was strongly inhibited by N--p-tosyl-L-lysine chloromethyl ketone.This investigation received financial support from the UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases, the Fundación Julio Cherny, and the Ministerio de Salud Pública y Medio Ambiente de la República Argentina. The authors gratefully acknowledge the technical assistance of Mr Esteban Bontempi. 相似文献
209.
I. J. Miller N. K. McCallum C. M. Kirk B. M. Peake 《Cellular and molecular life sciences : CMLS》1982,38(2):230-231
Summary The free radical oxidation of 1 and 6-tetrahydrocannabinol has been examined by spin trapping techniques and intermediates that would lead to cannabinol have been trapped. The 1st step in the oxidation of 1-THC involves the removal of 3-H, while for 6-THC, either 2-H or 5-H. Intermediates were isolated which could be pyrolysed to the diene and cannabinol. 相似文献
210.
J. Lamprecht R. Figurski Z. Lewicki A. Pawłowski 《Cellular and molecular life sciences : CMLS》1979,35(10):1386-1387
Summary Complete removal of villous as well as upper-crypt epithelium was achieved in vivo by vibration of an intestinal segment using tetraphenylboron sodium (TPB) as a disassociation agent.Acknowledgments. The authors thank Hicol Industrieterrein De Bosschen for supplying TPB. Research was supported by MR-II 1.3.14.p.2 grant. 相似文献