Variations in Excision Repair of UVB-Induced Pyrimidine Dimers in DNA of Human Skin in Situ

The excision repair kinetics of UVB (280–320 nm) ∗ -induced pyrimidine dimers in DNA of human skin in situ was determined for seventeen volunteers using a dimer-specific endonuclease from Micrococcus luteus in conjunction with agarose gel electrophoresis. Removal of pyrimidine dimers from human skin could be detected within 6 h after irradiation and the average half-life for removal of pyrimidine dimers was 11.0 h (±4.3 h). However, there was significant inter-individual variability of repair as indicated by a half-life coefficient of variation of 38%.