Measurement of 7-methyl- and 7-(2-hydroxyethyl)guanine DNA adducts in white blood cells of smokers and non-smokers

The goal of the present study was to measure the levels of 7-methylguanine and 7-(2-hydroxyethyl)guanine DNA adducts in human white blood cells in relation to smoking. DNA was isolated from samples of 11 smokers and eight non-smokers. The P-32-postlabelled 7-methylguanine and 7-(2-hydroxyethyl)guanine adducts were analysed by thin-layer chromatography (TLC) combined with a high pressure liquid chromatography (HPLC) assay. In smokers the mean 7-methylguanine and 7-(2-hydroxyethyl)guanine levels were 32.3 +/- 7.1 and 6.6 +/- 2.3 adducts per 10(8) nucleotides respectively. The corresponding values in non-smokers were 25.0 +/- 7.0 and 3.7 +/- 2.4 adducts per 108 nucleotides. There were significantly higher levels of 7-methylguanine and 7-(2-hydroxyethyl)guanine adducts in WBC in smokers than in non-smokers (p = 0.041; p = 0.018), respectively. A positive correlation between 7-methylguanine and 7-(2-hydroxyethyl)guanine levels was observed.