“…At that time too, Osterman-Golkar et al (1977) showed the chromatographic separation, after NaBH4 treatment, of 7-N-(2-hydroxyethyl)guanine from the acid hydrolysate of the liver DNA of mice, exposed acutely to 14C-vinyl chloride, and they attributed this result to formation of 7-N-(2-oxoethyl)dG residues, but they did not look in their DNA hydrolysates for etheno-dA and etheno-dC, which, on account of the method of exposure, may have been absent from their material or below the limits of detection.…”