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J C Cohen

Publications and source records attributed to J C Cohen.

94 records · Page 6Linked to original sources
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Mouse mammary tumor virus genes: regulation of expression by glucocorticoids and structural analysis with restriction endonucleases.

The production of mouse mammary tumor virus (MTV) is stimulated by treatment of mammary carcinoma cells with glucocorticoid hormones (e.g., dexamethasone). The reaction appears to be a primary and receptor-mediated phenomenon in which the rate of synthesis of MTV RNA is selectively increased; the maximally induced rate is reached within 15 min after addition of the hormone. Production of MTV RNA is also stimulated by dexamethasone in some but not all clonal isolates of nonmurine cells infected by the virus. Using restriction endonucleases, we have characterized both integrated and unintegrated viral DNA from clones of infected rat hepatoma (HTC) cells. We suggest that the site(s) in the rat cell genome into which MTV DNA integrates may be a determining factor for MTV RNA synthesis.

DNA Restriction Enzymes↗
PubMedDate not supplied

Dissociation between postprandial lipemia and high density lipoprotein cholesterol concentrations in endurance-trained men.

Previous studies have indicated an inverse relation between circulating high density lipoprotein (HDL) concentrations and the rate of chylomicron clearance. Because chronic exercise has been shown to augment chylomicron clearance, we measured HDL cholesterol concentrations and plasma triglyceride and retinyl palmitate responses to high- (140 g) and low- (50 g) fat meals in endurance-trained men. Plasma HDL cholesterol concentrations in these men ranged from 36 to 105 mg/dl. Intraindividual variation in the cholesterol concentration of the HDLs occurred primarily in HDL2. The magnitude of postprandial lipemia induced by both the high- and the low-fat meals was uniformly low compared with values reported previously for sedentary men and was not correlated with HDL cholesterol concentrations. Postprandial retinyl palmitate concentrations, which reflect chylomicron remnant metabolism, also showed no correlation with HDL cholesterol concentrations. These data indicate that the degree of postprandial lipemia is not the primary determinant of HDL cholesterol concentrations in endurance-trained men. Accordingly, the wide range of HDL cholesterol concentrations measured in these men must be attributable to other factors.

Adult↗