Folic acid and chromosome breakage. I. Implications for genotoxicity studies

Chromosome breakage is significantly lower in culture medium containing folic acid than in medium that does not. This effect is similar to that observed in studies of chromosome fragile sites and suggests that fragile sites and some types of chromosome breakage may share a common mechanism. It also suggests that high non-physiological levels of folic acid in many commonly used culture media may artifactually decrease chromosome breakage.

Comparative studies on spontaneous and mitomycin-C-induced sister-chromatid exchanges in smokers and non-smokers

Both spontaneous and mitomycin-C-induced sister-chromatid exchanges were analyzed in 6 smokers and 6 non-smokers. The average number of spontaneous SCE in smokers' cells was 8.33 +/- 1.08. The frequency in the non-smoking controls was 4.41 +/- 0.72. This difference is highly significant (P less than 0.001). Smokers also had more SCE at all levels of mitomycin C testes. Analysis of variance showed these differences to be highly significant (P less than 0.001).