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Biomedical subjects

J Cohn

Publications and source records attributed to J Cohn.

At least 73 records · Page 4Linked to original sources
PubMed1972

Lead and methyl mercury: effects of acute exposure on cytochrome P-450 and the mixed function oxidase system in the liver.

The rat liver mixed function oxidase system which is responsible for the metabolism of endogenous and exogenous compounds has been shown to be affected by lead and methyl mercury. Administration of these environmental pollutants to rats results in a decrease in cytochrome P-450 content and inhibition of in vitro N-demethylase and hydroxylase activities. The in vitro enzyme-inhibiting effects of the metals found pharmacological expression in the whole animal by prolongation of hexobarbital-induced sleeping times.

Aniline Compounds↗
PubMed1972

Coagulase and deoxyribonuclease activities of staphylococci isolated from clinical sources.

A total of 504 clinical isolates of the family Micrococcaceae were tested for coagulase, deoxyribonuclease, clumping factor, and phosphatase to determine whether there is a correlation between the results of these tests and the pathogenicity of staphylococci. In the tests for coagulase production, it was found that either human or rabbit plasma could be used with broth cultures, whereas rabbit but not human plasma was satisfactory when microorganisms removed from solid culture medium were used. Deoxyribonuclease production correlated better than the fermentation of mannitol with coagulase production. The use of methyl green, Toluidine Blue O, or acridine orange offered no advantage over the use of HCl for detecting the production of deoxyribonuclease. Neither the presence of clumping factor nor the production of phosphatase correlated well with coagulase production. Strains of staphylococci that did not produce coagulase and deoxyribonuclease were isolated as frequently as, and from a greater variety of clinical sources than, strains which produced these substances. It is concluded that the production of coagulase and deoxyribonuclease are properties of staphylococci which are not necessarily indicative of potential pathogenicity of the organisms for man.

Acridines↗
PubMedDate not supplied

The nuclear lamina is a meshwork of intermediate-type filaments.

The nuclear lamina, a protein meshwork lining the nucleoplasmic surface of the inner nuclear membrane, is thought to provide a framework for organizing nuclear envelope structure and an anchoring site at the nuclear periphery for interphase chromatin. In several higher eukaryotic cells, the lamina appears to be a polymer comprised mainly of one to three immunologically related polypeptides of relative molecular mass (Mr) 60,000-75,000 (60-70K) termed lamins. Three lamins (A, B, and C) are typically present in mammalian somatic cells. Previous studies on nuclear envelopes of rat liver and Xenopus oocytes suggested that the lamina has a fibrillar or filamentous substructure. Interestingly, protein sequences recently deduced for human lamins A and C from complementary DNA clones indicate that both of these polypeptides contain a region of approximately 350 amino acids very similar in sequence to the coiled-coil alpha-helical rod domain that characterizes all intermediate-type filament (IF) proteins. Here we analyse the supramolecular organization of the native nuclear lamina and the structure and assembly properties of purified lamins, and show that the lamins constitute a previously unrecognized class of IF polypeptides.

Animals↗