Mycobacterium-avium complex.

The ubiquitous MAC causes disseminated disease in a large proportion of patients with AIDS. It will become an increasingly important clinical pathogen as more patients survive within the context of prolonged immunodeficiency. The primary risk factor for DMAC is CD4 < 100 mm3 and thus the institution of adequate prophylaxis will significantly reduce its presentation in advanced HIV infection. For those patients presenting with DMAC, therapy with a multiple drug regimen including a macrolide is indicated. Because of potential toxicities and interactions in these debilitated patients, however, the ideal approach is to employ a minimum number of drugs with maximal clinical activity.

Selenium and vitamin E in horses.

A survey of selenium and vitamin E concentrations in horses was conducted at four breeding farms in New York. There were no significant changes in mean blood selenium concentrations in horses at the three sampling dates whereas vitamin E concentrations underwent seasonal fluctuations. The mean blood selenium concentration in this survey for horses fed local feed was 7.7 microgram/dl. Horses fed commercial feed had a mean blood selenium concentration of 15.6 microgram/dl. A 0.94 correlation coefficient was found between blood glutatione peroxidase activity and blood selenium concentrations in horses. The effect of oral and parenteral selenium administration on blood selenium concentrations and blood glutathione peroxidase activity was also investigated. Oral supplementation of 1 mg selenium per day increased blood selenium concentrations above levels associated with myodegeneration in horses and foals. Parenteral supplementation trials with mares at late gestation indicate that only limited amounts of selenium cross the placental barrier. Parenteral supplementation of mares during gestation and lactation or supplementation of foals beginning at birth will increase blood selenium levels in foals above that associated with selenium/vitamin E deficiency.