Spectral changes resulting from the interaction of some N-alkyl nitrosamines and rat liver microsomes

Summary Dimethyl (DMN) and diethyl nitrosamine (DEN) do not give characteristic spectral changes upon interaction with rat liver microsomes, while dipropyl (DPN) and dibutyl (DBN) nitrosamine cause type I spectral changes. The spectral binding constant is 100 mM for DPN and 1.17 mM for DBN. The maximal spectral change is 3.2×10⁶ and 1.0×10⁶ absorbance units per milligram protein for DPN and DBN respectively.Acknowledgment. This work was supported by Grants AM 13195-07 from the National Institute of Health (USA) and from the Consejo Nacional de Investigaciones Cientificas y Técnicas (Argentina).     

Synthesis and properties of benzo [d,e]estra-1,3,5(10)-triene-3,17β-diol 17-acetate

Summary A new pentacyclic analogue of estradiol, benzo[d, e]estradiol 17-acetate, has been prepared and investigated for its hormonal and antitumor activity. Unlike related testosterone derivatives, the new compound did not display any interesting property.     

Riboflavin in the blood serum,the skin and the venom of some snakes of Burma

Zusammenfassung Es wurden sowohl giftige als auch ungiftige Schlangen aus Burma auf den Gehalt an Flavinen in Blut und Haut untersucht.     

Resistance of cold-exposed rats to aflatoxin

Summary Male rats kept at a temperature of 4°–5°C were refractory to a lethal dose of aflatoxin compared to animals at 20°–21°C which exhibited a high mortality and marked liver damage. It is suggested that this decreased susceptibility is mediated through a stimulated microsomal drug-metabolizing system in cold environment.     

Investigations into the effects of ACTH on the half-life of mitochondrial proteins in the rat adrenal cortex

Summary ACTH elongates the half-life of the mitochondrial proteins from the rat adrenal cortex, and chloramphenicol inhibits this effect of ACTH. The hypothesis is advanced that the ACTH-provoked stabilization of the adrenocortical mitochondrial proteins requires continuous mitochondrial DNA-dependent protein synthesis.     

Purification of a nuclease from human serum

Summary The purification procedure for a nuclease from human serum is described. It includes ammonium sulfate precipitation, chromatography on DEAE-Sephadex and on Sephacryl-S 200, and preparative electrophoresis. The enzyme, purified about 2000-fold, is homogeneous in a sodium dodecyl sulfate electrophoretic system, where it has a mol. wt of 78,000. The pH optimum lies around pH 6.5; it is a sugar-nonspecific endonuclease.Acknowledgment. This work has been supported by a research grant from Stiftung Volkswagenwerk through the Akademie der Wissenschaften und der Literatur, Mainz. We thank Mrs R. Nehrbass and Mrs C. Wolpert for technical assistance.     

Connection between membrane adenosinetriphosphatase activity and potassium transport in erythrocyte ghosts

Zusammenfassung In ATP angereicherten menschlichen Erythrocytenstroma konnte zwischen Ouabainempfindlicher Membran-ATPase-Aktivität und aktiver K⁺-Akkumulation ein Zusammenhang festgestellt werden: die Hydrolyse eines ATP-Moleküls ist mit der Akkumulation von zwei K⁺-Ionen verbunden.