The benefits of physical activity in reducing cardiovascular disease (CVD) are thought to be mediated through changes in blood lipids, insulin sensitivity, and thrombogenic factors. Few studies have addressed the effects of both long-term physical activity and inactivity on these factors. The authors assessed associations between long-term leisure-time physical activity, television watching, and biomarkers of CVD risk among 468 healthy male health professionals. Prior to blood collection in 1993-1994, physical activity and television watching were assessed biennially from 1986 to 1994 by a questionnaire. Physical activity was expressed as metabolic equivalents-hours per week. Multivariate linear regression analyses showed that metabolic equivalents-hours in 1994 were significantly associated with high density lipoprotein cholesterol (HDL cholesterol) (positively) and with leptin and C-peptide (inversely). The average number of hours of television watching assessed in 1994 was significantly positively associated with low density lipoprotein cholesterol and significantly inversely associated with HDL cholesterol and apolipoprotein A1. Average hours of television watching per week assessed in 1988-1994 was positively associated with leptin levels (p < 0.01). The associations of television watching and vigorous activity with leptin and HDL cholesterol were independent of each other. In conclusion, physical activity and television watching were significantly associated with several biochemical markers of obesity and CVD risk.

During both animal and clinical studies with manganese (II) N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'-bis(phosphate) (DPDP), enhanced rims around liver tumors on magnetic resonance (MR) images have been observed. To elucidate the origins of these rims and to assess their potential value in the differential diagnosis of liver masses, the authors studied 15 rats with induced hepatocellular carcinoma (HCC), 10 rats with implanted Novikoff hepatomas, and 11 rabbits with implanted VX2 carcinomas. A total of 69 primary and secondary liver cancers from these three animal models were studied. Mn-DPDP- and gadolinium tetraazacyclododecantetra acetic acid (DOTA)-enhanced MR images were compared. On the Mn-DPDP-enhanced images, 34 peritumoral rims of various patterns were displayed, all of which were exclusively related to the presence of highly malignant primary and secondary liver tumors. Peritumoral zones of malignant infiltration, surrounding parenchymal compression, and bile duct proliferation were seen to be the origin of these rims after comparison of MR images with the corresponding microangiograms and histologic specimens.

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