title: Suppressive action of near-ultraviolet light on ouabain resistance induced by far-ultraviolet light in Chinese hamster cells.
abstract: The interaction between ultraviolet light (UV-C) from germicidal lamps (254 nm) and near-ultraviolet light (UV-B) from Westinghouse Sun Lamps (290-345 nm) was studied in Chinese hamster V79 cells by measuring the effectiveness of combined exposures to induce the resistance to 6-thioguanine or to ouabain. Exposure of cells to a conditioning dose of UV-B (approximately 70% survival) results in significant inhibition of the induction by UV-C of cells resistant to ouabain. The inhibition is lost, however, if cells are incubated for 12 h at 37 degrees C between exposures. Inhibition is also observed when cells are preirradiated with a dose of UV-B filtered with polystyrene (300-345 nm) which, in itself, has no effect on cell killing. Conditioning exposures of unfiltered or filtered UV-B light do not inhibit the induction of 6-thioguanine-resistant cells by UV-C light, and the effects of UV-B and UV-C light are largely independent.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D004351:Drug Resistance / Q000528:radiation effects*; D010042:Ouabain / Q000494:pharmacology*; D011137:Polystyrenes / Q000494:pharmacology; D013866:Thioguanine / Q000494:pharmacology; D014466:Ultraviolet Rays
chemical_list: D011137:Polystyrenes; D010042:Ouabain; D013866:Thioguanine