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Hypertension is highly prevalent among African Americans, who are also more likely than whites to develop end-organ complications of hypertension. Traditional diuretic-based stepcare therapy has successfully reduced such complications of hypertension as stroke, congestive heart failure, and premature death in all populations tested. Prevention of coronary deaths has been less successful. Potentially adverse metabolic effects of thiazide diuretics and some beta-blockers may partially explain the less successful cardiac outcomes. Use of antihypertensive agents lacking adverse metabolic effects but still achieving effective blood pressure control could improve cardiac outcomes while maintaining the benefits achieved with older forms of therapy. Achievement of improved cardiac outcomes is now one of the principal goals of hypertension research and treatment.

The side-effect profile of labetalol was assessed in 34 patients with mild to moderate essential hypertension who had previously experienced side effects during beta-blocker therapy. The most frequently reported beta-blocker side effects were fatigue, impotence, cold extremities, and depression. After discontinuing their previous beta-blocker for 4 weeks, labetalol was titrated (100-400 mg b.i.d.) to achieve blood pressure control. Twenty-seven of 34 patients did not have a recurrence of a beta-blocker related side effect while receiving labetalol. The most common new side effect with labetalol was dizziness (3 patients). As judged by the attending physician and the patient, labetalol was better tolerated than conventional beta-blocker therapy in 30 of 34 patients (88%). Twenty-four of 34 patients (71%) preferred labetalol over previous therapy. Labetalol controlled blood pressure in 30 of 34 patients (88%). At equal antihypertensive doses, some side effects common to beta-blockers are seen less frequently with labetalol.

A direct radioimmunoassay for aldosterone in unextracted plasma was developed using a highly sensitive and specific antiserum and 125I-labeled aldosterone. This new method was compared with the previously used assay based on methylene chloride extraction and column chromatography and with a micromethod utilizing methylene chloride extraction alone. Concentrations of 2 pg/ml aldosterone can be measured in 25 microliter plasma. The within-assay coefficient of variation ranged between 4.0% and 5.3% over a sixfold range of aldosterone concentrations, and the between-assay coefficient of variation ranged between 5.0% and 9.4% over a tenfold range. The correlation coefficients among the three methods varied between 0.97 and 0.99, and results were virtually identical between the new direct and the standard chromatography methods. Normal values on unrestricted salt intake were 68 +/- 28 pg/ml (n = 30, mean +/- SD) in seated humans. In conclusion, this is an extremely simple, truly direct microradioimmunoassay for plasma aldosterone that is accurate over a wide range of plasma concentrations, is exquisitely sensitive, and provides results identical to those obtained with established methods.