Sublethal effect of a weak intermittent magnetic field on the development of Xenopus laevis (Daudin) tadpoles.

In three repeated experiments with three different litters of Xenopus laevis (Daudin) tadpoles, three cohorts were reared in an aquarium under the "saw-tooth" magnetic field produced by a television set. Their maturation times are compared with those of three corresponding control cohorts grown in an unexposed aquarium. In the exposed aquarium, the magnetic field amplitude was less than 25 microT and the frequency in the extremely-low-frequency and very-low-frequency wavebands. Neither the exposed nor the unexposed cohorts suffered significant mortality and malformations. However, the exposed tadpoles took about 5 days more than the unexposed ones to reach metamorphosis. The differences in mean maturation times between the exposed and control cohorts were extremely significant (P < 0.001). The results show that a biological population can suffer a sublethal effect when exposed to the magnetic field of a TV set for a long time in the course of juvenile life stages, and that this effect can consist of a delay in reaching the adult stage.

Cardiac rehabilitation as secondary prevention. Agency for Health Care Policy and Research and National Heart, Lung, and Blood Institute.

This Quick Reference Guide for Clinicians highlights the conclusions and recommendations from Cardiac Rehabilitation, Clinical Practice Guideline No. 17, which was formulated by a panel representing the major health care disciplines involved in cardiac rehabilitation. The conclusions and recommendations were derived from an extensive and critical review of the scientific literature pertaining to cardiac rehabilitation, as well as from the expert opinion of the panel. This guide addresses the role of cardiac rehabilitation and the potential benefits to be derived in the comprehensive care of the 13.5 million patients with heart disease in the United States, as well as the 4.7 million patients with heart failure and the several thousand patients undergoing heart transplantation. This Quick Reference Guide for Clinicians highlights the major effects of multifactorial cardiac rehabilitation services: medical evaluation; prescribed exercise; cardiac risk factor modification; and education, counseling, and behavioral interventions. The outcomes of and recommendations for cardiac rehabilitation services are categorized as to their effects on exercise tolerance, strength training, exercise habits, symptoms, smoking, lipids, body weight, blood pressure, psychological well-being, social adjustment and functioning, return to work, morbidity and safety issues, mortality and safety issues, and pathophysiologic measures. Patients with heart failure and after cardiac transplantation, as well as elderly patients, are specifically addressed. Alternate approaches to the delivery of cardiac rehabilitation services are presented.

Effects of weight reduction on blood lipids and lipoproteins: a meta-analysis.

Studies designed to examine effects of weight reduction by dieting on total cholesterol (TC), low-density-lipoprotein cholesterol (LDL-C), high-density-lipoprotein cholesterol (HDL-C), very-low-density-lipoprotein cholesterol (VLDL-C), and triglycerides (TGs) have reported inconsistent results. The purpose of this study was to quantify effects of weight loss by dieting on lipids and lipoproteins through the review method of meta-analysis. Results from the 70 studies analyzed indicated that weight reduction was associated with significant decreases (P less than or equal to 0.001) and correlations (P less than or equal to 0.05) for TC (r = 0.32), LDL-C (r = 0.29), VLDL-C (r = 0.38), and TG (r = 0.32). For every kilogram decrease in body weight, a 0.009-mmol/L increase (P less than or equal to 0.01) in HDL-C occurred for subjects at a stabilized, reduced weight and a 0.007-mmol/L decrease (P less than or equal to 0.05) for subjects actively losing weight. Our results indicate that weight reduction through dieting can be a viable approach to help normalize plasma lipids and lipoproteins in overweight individuals.