A. Immunoslot blot assay result for the standard curve. A standard for DNA measurement was generated by the in vitro reaction of calf thymus DNA with 3H-labeled N-methyl N-nitrosourea. The DNA adduct levels were determined by scintillation counting. The labeled DNA was then diluted with naïve calf thymus DNA to a final concentration of 25, 50, 100, 250, 500, 1000, or 2000 fmol adduct per μg DNA.
B. Immunoclot blot assay result for a dose-response experiment. The lymphocytes from 3 healthy volunteers were treated with ENU at doses of 0, 0.21, 0.43, 0.64, 0.85, and 1.60 mM.