[Effect of dimethyl sulfoxide on the extent of DNA single-strand breaks and alkali-labile sites induced by 365 nm UV-radiation in human blood lymphocyte nucleoids].

It is shown that exposure of 365 nm UV radiation at doses of 10, 20 and 50 kJ/m2 induces a dose-dependent increase in DNA single-strand breaks and alkali-labile sites (SSB and ALS) detected by comet and halo assays in human blood lymphocyte nucleoids. Adding 10% dimethyl sulfoxide (DMSO) reduces the SSB and ALS yields--in 3 times. A strong drop in the output of UV-A-induced SSB and ALS in lymphocyte nucleoids in the presence of DMSO shows the leading role of *OH radicals in this DNA damage formation under exposure to 365-nm UV-radiation.