title: Cumulative effects from repeated exposures to ultraviolet radiation.
abstract: Repeated exposures to subliminal doses of UVR, given at 24-hr intervals, resulted in a lowering of the erythema threshold dose. At erythemogenically equivalent doses, UV-A was the most effective and UV-C the least. A similar and more pronounced effect was observed following repeated exposures to subthreshold doses of UV-A and topically applied 8-methoxypsoralen. These findings provide quantitative evidence for the cumulative nature of acute UVR damage in human skin.
mesh_terms: D000293:Adolescent; D000328:Adult; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D004890:Erythema / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008730:Methoxsalen / Q000009:adverse effects; D012867:Skin / Q000187:drug effects / Q000528:radiation effects; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D008730:Methoxsalen