Effects of caffeine on sister chromatid exchange (SCE) after exposure to UV light or triaziquone studied with a fluorescence plus giemsa (FPG) technique.

Studies are reported that are designed to analyze the mechanism by which caffeine reduces the induction of SCE by UV light or alkylating agents. The substantial points are (1) caffeine does not inhibit SCE formation, and (2) the caffeine-mediated apparent decrease of SCE induction after UV or triaziquone exposure is due to a selective destruction of those metaphases otherwise exhibiting a high number of SCE. These findings and their relevance to the ascertainment of the SCE-forming process are discussed.