Photorepair of pyrimidine dimers in human skin in vivo.

The exposure of human skin in vivo to UV radiation emitted from a sunlamp induces the formation of pyrimidine dimers. The number of dimers, as detected by UV-endonuclease, decreases following exposure of the UV-irradiated skin to visible wavelengths of light. These results suggest that humans possess a mechanism by which pyrimidine dimers are photorepaired upon illumination of human skin in vivo with visible light.