De Flora S, Camoirano A, Izzotti A, Bennicelli C
Institute of Hygiene and Preventive Medicine, University of Genoa, Italy.
Carcinogenesis. 1990 Dec;11(12):2171-7. doi: 10.1093/carcin/11.12.2171.
The light emitted by halogen lamps induced mutations in Salmonella typhimurium and DNA damage in Escherichia coli, as shown by the hypersensitivity of DNA repair-deficient strains. The mutagenicity of halogen lamps was considerably higher than that of fluorescent light and of sunlight, even at much lower illuminance levels. Excision mechanisms and SOS functions were involved in repairing light-induced base-pair substitutions and frameshift errors in bacterial DNA. At variance with solar irradiation, which produces mutagenic effects over a wide UV spectrum, genotoxicity of halogen lamps was almost exclusively due to far-UV wavelengths transmissible through UV-R-250 and UV-R-280 interference filters. The main mutagenic component of fluorescent light (254 nm) were almost 10(4)-fold more mutagenic than near-UV wavelengths (365 nm). All light sources exhibited some residual mutagenicity even following filtration through various cloths. On the other hand, appropriate glass or plastic covers consistently prevented mutagenic effects. This emphasizes the urgent need for a compulsory shielding of halogen and fluorescent lamps in order to prevent unnecessary exposures to genotoxic and potentially carcinogenic UV radiations.
卤钨灯发出的光可诱导鼠伤寒沙门氏菌发生突变，并导致大肠杆菌的DNA损伤，这可通过DNA修复缺陷菌株的超敏反应得到证明。即使在低得多的照度水平下，卤钨灯的诱变性也大大高于荧光灯和阳光。切除机制和SOS功能参与修复细菌DNA中光诱导的碱基对替换和移码错误。与在广泛的紫外光谱范围内产生诱变作用的太阳辐射不同，卤钨灯的遗传毒性几乎完全归因于可透过UV-R-250和UV-R-280干涉滤光片的远紫外波长。荧光灯的主要诱变成分（254nm）的诱变性比近紫外波长（365nm）高近10^4倍。即使通过各种布料过滤后，所有光源仍表现出一定的残余诱变性。另一方面，适当的玻璃或塑料罩始终能防止诱变作用。这强调了迫切需要对卤钨灯和荧光灯进行强制性屏蔽，以防止不必要地暴露于具有遗传毒性和潜在致癌性的紫外线辐射。
