Oxidative damage to DNA: Formation and measurement

Emphasis is placed in this short survey on recent aspects of the formation and the measurement of oxidative base damage to both isolated and cellular DNA. New insights in the mechanism of the formation of tandem base lesions were gained from detailed studies involving O-18-labeling experiments. Information is also provided on both singlet oxygen and one-electron oxidation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) an ubiquitous DNA marker of oxidative reactions. Recent improvements in the HPLC-MS/MS measurement of the level of several single oxidized bases within cellular DNA were achieved. The association of DNA repair glycosylases with an improved version of the comet assay has allowed the assessment of two classes of base damage at doses of ionizing radiation as low as 0.2 Gy.