Labetalol: potent antihypertensive agent that blocks both alpha- and beta-adrenergic receptors.

Labetalol was administered as the sole antihypertensive agent to 20 ambulatory patients with mild to moderate hypertension. The mean systolic and diastolic blood pressures (+/- standard error of the mean) with the patients sitting fell significantly (P < 0.001), from 145.5 +/- 3.2 and 103.7 +/- 1.6 mm Hg respectively at the start of labetalol therapy (after a period free of antihypertensive medication) to 125.7 +/- 2.0 and 87.2 +/- 1.1 mm Hg by the end of the trial. The diastolic blood pressure was well controlled (90 mm Hg or less) with labetalol therapy in 90% of the patients. The medication was well tolerated, and no orthostatic fall in the diastolic blood pressure was observed. Pharmacologically labetalol most closely resembles a combination of a nonselective beta-adrenergic blocker like propranolol and a postsynaptic alpha-adrenergic blocker like prazosin.     

Cholesteryl ester and apolipoprotein E transfer between human high density lipoproteins and chylomicrons

The transfer of cholesteryl esters and apolipoprotein E has been studied between plasma HDL and chylomicrons isolated either from ascitic fluid or from the plasma of a patient with type V hyperlipoproteinemia. Whereas apolipoprotein E transfer was rapid and occurred at low temperature, cholesteryl ester transfer was suppressed at 4 degrees C. Apolipoprotein E transfer did not depend upon the presence of cholesteryl ester transfer protein and was in fact inhibited by the partially purified preparation of this protein. Apolipoprotein E transfer was not increased by reduction with dithiothreitol. The transfer of cholesteryl esters increased sharply at a chylomicron to HDL ratio of cholesteryl ester above 1/10, a value which may be of physiological significance at the peak of postprandial lipemia. At this ratio, the transfer of apolipoprotein E was minimal and increased only at ratios above 2/1. From these results, it is concluded that there is no connection between apolipoprotein E and cholesteryl ester transfer from HDL to chylomicrons. It is, therefore, proposed that whereas chylomicron apolipoprotein E is acquired rapidly and mostly in the lymphatic system, the concentration of chylomicron cholesteryl esters increases significantly and independently in the circulation.     

Total Screening of Blood Donations for Australia (Hepatitis Associated) Antigen and its Antibody

During a period of one year all of 105,724 blood donations were tested for Australia (Au) antigen and its antibody by rapid immunoelectro-osmophoresis—86 (1 in 1,229) were positive for antigen and 67 (1 in 1,578) positive for antibody. Second donations by previously negative donors reduce the overall incidence of positives. Men prisoners have a significantly higher incidence of Au antigen (1 in 153) than non-institutionalized men (1 in 803). The latter have a significantly higher incidence of antigen than women (1 in 2,019). Only one antigen-positive donor was incubating acute viral hepatitis. Failure to detect one strong and one weak antigen was responsible for two cases of posttransfusion Au-antigen-positive hepatitis.