Increase in blood-brain barrier permeability by altitude decompression.

Previous studies indicated that exposure to compression-decompression increases blood-brain barrier (BBB) permeability to vital dyes and antibiotics. This report concerns functional and ultrastructural BBB changes induced by altitude decompression. A 2% trypan blue solution was intravenously injected (4 ml.

Increase of plasma renin activity in male and female rabbits subjected to dysbaric conditions.

The renin-angiotensin-aldosterone system may be implicated in hemodynamic alterations occurring in dysbaric disorders. This report concerns changes in plasma renin activity (PRA) induced by exposure of rabbits to a compression-decompression schedule that does not normally produce clinical manifestations of decompression sickness (DS). The results revealed a significant increase in PRA in 19 of 23 animals following dysbaric exposure.

Meiotic chromosomal changes and sterility produced by nitrogen mustard and procarbazine in mice.

Treatment and survival of reproductive-age patients with chemotherapy raises the question of possible effects on procreative ability. An attempt has been made to establish an animal model system. The anticancer agents nitrogen mustard and procarbazine caused decreased fertility in mice of both sexes and induced meiotic chromosomal abnormalities, at least in the male.

Amelioration of decompression sickness in mice by pretreatment with cyproheptadine.

Substances that stimulate smooth muscle have been previously implicated in the pathogenesis of decompression sickness. This concept was strongly supported by the demonstration that compounds that combine activities against histamine, bradykinin, and serotonin prevent or ameliorate decompression sickness. This communication deals with the prophylactic effect of cyproheptadine (Periactin), a drug exhibiting such pharmacologic properties.

Dysbaric osteonecrosis. Etiological and pathogenetic concepts.

Dysbaric osteonecrosis appears to be independent of decompression sickness. The 2 conditions, however, may share etiologic and pathogenetic factors. The incidence of osteonecrosis is influenced by the number of hyperbaric exposures, extent of pressure, decompression profile and possibly by the rate of compression and degree of obesity.

Blood-brain and blood-lung barrier alteration by dysbaric exposure.

Failure of certain circulating substances to penetrate specific organs led to the concept of blood-organ barriers. Such barriers can be altered by various physical or chemical means. This report concerns modification of the blood-brain barrier (BBB) and blood-lung barrier (BLB) by dysbaric exposure.

Dysbaric osteonecrosis in mice.

The histopathology of dysbaric osteonecrosis and the influence of the number of exposures, compression rate, and obesity on the incidence and latency of the lesion were studied in 438 mice (2505 bones were examined). The animals were subjected to 75 psig air pressure for 2-6 hours (single or multiple exposures). Compression was rapid or stage.