Hormone-dependent processing of the avian progesterone receptor

Avian progesterone receptor exists as two forms, A and B, with molecular weights of 79,000 and 110,000 daltons, respectively. The origin and significance of these two forms is an area of active investigation and debate. Monoclonal antibodies produced against these two forms were used to examine receptor stability in cytosol and changes in the receptor forms induced by hormone binding. The lability of hormone binding at elevated temperatures is well documented. Analysis by Western blotting showed the receptor was stable in freshly prepared oviduct cytosol for 2 hr at 37°C, while hormone binding was lost within 30 min. However, loss of receptor through degradation was seen when cytosol was prepared from frozen tissue or when homogenization was excessive. Progesterone was injected into diethylstilbestrol-stimulated chicks to examine, in vivo, effects of hormone treatment on receptor forms in the cytosol and nuclear fractions. Progesterone treatment caused a time- and dose-dependent conversion of the A receptor to a form (A′) with a slower electrophoretic mobility. The cytosolic progesterone receptor was divided equally between the B and A forms, while the nuclear receptor was predominantly A′. The amount of nuclear receptor was consistently less than cytosolic receptor. Receptor phosphorylation was analyzed by incubating tissue minces with [³²P]orthophosphate with or without progesterone followed by immune isolation of receptor forms. Progesterone treatment caused a time-dependent increase in cytosol receptor phosphorylation which was evident after 5 min of treatment. This phosphorylation was observed with both the A and B receptor forms. The results indicate that receptor phosphorylation is a very early event during progesterone action.     

Industrial toxicology of metals of the platinum group

Metals of the platinum group have found important application in technology and industry. Compounds of these metals display a broad spectrum of toxic effects on the organism. In persons dealing with them in the production, they induce allergic occupational diseases of the respiratory passages, dermatoses, affections of the eyes. Their resorptive chronic effect in experiment is characterized by reduction in the body mass of the animals and the content of haemoglobin in the blood, by disturbances of the protein-synthesizing function of the liver, decreased cholinesterase activity in the blood, impaired carbohydrate and lipid metabolism, reduced concentrating capacity of the liver, development of glomerulonephritis. Platinum and platinoids irritate mucous membranes and skin. They penetrate the organism through intact skin. Data on the distribution of the metals in the organs and on their elimination from the organism are reported. Toxicity of the metals of the platinum group is correlated with valence of the compounds and with electron structure. MAC for milling and condensation aerosols of poorly soluble compounds (metal and its oxides) are recommended at 0.1 mg/m3. For aerosols of all soluble compounds of platinum and platinoids, MAC of 0.001 mg/m3 are recommended.     

Nonspecific and antigen-specific adhesiveness of circulating lymphocytes in dysentery patients undergoing combined therapy using thymalin and indomethacin

Nonspecific adhesiveness of lymphocytes to polyacrylonitrile fiber and the antigen-specific adhesiveness of T-lymphocytes to Shigella flexneri pellicular immunosorbent have been studied in dysentery patients. Short courses of treatment with indomethacin, but not with thymalin (the preparation of thymic hormones), used for immunomodulation, have accelerated the normalization of nonspecific lymphocyte adhesiveness during regression of the disease, while indomethacin, in contrast to thymalin, inhibits antigen-specific T-lymphocyte adhesiveness which increases with the development of immune response.