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Twelve hypertensive black males completed the study, which was conducted to evaluate the effect of metoprolol on 24-h ambulatory blood pressure (ABP). Study participants took 50 mg to 100 mg metoprolol twice daily for a minimum of 3 weeks. Metoprolol had no significant effect on blood pressure (147/90 +/- 11/8 mm Hg v 151/88 +/- 16/8 mm Hg, baseline v treated, respectively) in spite of causing significant reductions in heart rate (87 +/- 9 beats/min v 69 +/- 7 beats/min, P < .001). Only one subject had a > or = 10 mm Hg decrease in 24-h diastolic blood pressure. The nighttime fall in blood pressure was minimized by metoprolol and clinically significant increases in daytime or nighttime blood pressure were noted in 58% of patients. Metoprolol therapy failed to lower blood pressure and eliminated the normal nighttime decline in blood pressure. Since the nighttime decline in blood pressure is thought to protect against target organ damage, it may be important to identify antihypertensive agents which preserve or enhance the nighttime blood pressure dip.

This is a report emanating from a 31-member interdisciplinary group, some with 10 years experience in artificial heart research. The development of an implantable, biventicular orthotopic cardiac prosthesis is described, and the result of 24 calf experiments are summarized. Rather than pursuing solely long-term survival, the team has sought an understanding of the pathophysiological mechanisms which have limited the duration of such experiments to date.

Skin surface lipids were extracted from volunteers who had been ranked according to the duration of protection from mosquitoes by diethyltoluamide. These lipids were analyzed by GLC-mass spectrometry for their fatty acid contents. Correlations were found between total skin lipid content and protection time of diethyltoluamide and between certain fatty acid concentrations in the skin lipids and the protection time of diethyltoluamide.

Changes in planktonic microfossil assemblages in Atlantic and Pacific sediment cores of Late Cenozoic age correspond in a general way with a horizon recognized in neritic sediments of the northern Gulf of Mexico. Geological evidence from the Gulf Coast indicates that the changes occurred near the end of the Aftonian interglaciation of the early Pleistocene rather than at the end of the Pliocene, as proposed by other investigators.