[Prevention of ultraviolet insufficiency after a long stay by humans in an isolation chamber]

The purpose of this study was to investigate biological effects of various regimens of ultraviolet irradiation in order to prevent UV insufficiency in men long kept in an enclosure. The subjects were kept for 60 days under artificial illumination in a Moscow laboratory in winter time. Two different regimens of UV irradiation were used and compared: 20 exposures at a dose of 0.75 MED and 20 exposures at incremental doses from 0.5 to 2 or 3 MED. Before and after 10 and 20 exposures (with medium-range radiation being predominant) the skin state, vitamin and mineral metabolism, and cytotoxicity of natural killers were investigated. The experimental observations allowed the conclusion that prophylaxis of UV insufficiency in men long kept in an enclosure can best be provided by UV irradiation at an incremental dose up to 2 MED. During this exposure skin sensitivity to UV radiation decreased, the content of vitamins D, A, E and that of Ca, P, Cu grew, and cytotoxicity of natural killers lightly increased. UV irradiation at a dose of 0.75 MED proved inadequate and that at a dose of 3 MED induced signs of excessive irradiation.