0000000000379248
AUTHOR
Beate Volkmer
Oxidative stress impairs the repair of oxidative DNA base modifications in human skin fibroblasts and melanoma cells.
Irradiation of mammalian cells with solar light is associated with the generation of reactive oxygen species (ROS) and oxidative stress, which is mediated in part by endogenous photosensitizers absorbing in the visible range of the solar spectrum. Accordingly, oxidative DNA base modifications such as 7,8-dihydro-8-oxoguanine (8-oxoG) are the predominant types of DNA damage in cells irradiated at wavelengths >400 nm. We have analysed the repair of oxidative purine modifications in human skin fibroblasts and melanoma cells using an alkaline elution technique, both under normal conditions and after depletion of glutathione. Similar repair rates were observed in fibroblasts and melanoma cells f…
Visible light (>395nm) causes micronuclei formation in mammalian cells without generation of cyclobutane pyrimidine dimers
Solar radiation gives rise to DNA damage in mammalian cells not only directly by excitation of DNA, which generates predominantly pyrimidine dimers, but also indirectly by the excitation of endogenous photosensitizers, which causes oxidative DNA modifications. The latter mechanism has a low quantum yield, but it is the only one proceeding in the visible range of the spectrum. To investigate its relevance for the genotoxicity of sunlight, we have analysed the generation of micronuclei associated with the induction of oxidative DNA damage by visible light in melanoma cells and primary human skin fibroblasts. Similar yields of light-induced oxidative DNA base modifications sensitive to the rep…
Influence of GSM signals on human peripheral lymphocytes: study of genotoxicity.
Exposure to radiofrequency (RF) electromagnetic fields (EMF) is continuously increasing worldwide. Yet, conflicting results of a possible genotoxic effect of RF EMF continue to be discussed. In the present study, a possible genotoxic effect of RF EMF (GSM, 1,800 MHz) in human lymphocytes was investigated by a collaboration of six independent institutes (institutes a, b, c, d, e, h). Peripheral blood of 20 healthy, nonsmoking volunteers of two age groups (10 volunteers 16-20 years old and 10 volunteers 50-65 years old) was taken, stimulated and intermittently exposed to three specific absorption rates (SARs) of RF EMF (0.2 W/kg, 2 W/kg, 10 W/kg) and sham for 28 h (institute a). The exposures…