Selected ion chromatograms obtained during the GC/MS analysis of PBMC DNA.

(A) Represents a mixture of trimethylsilylated standards. (B) The chromatogram demonstrates the higher abundance ions and the chromatogram in panel C shows the lower abundance ions of a trimethylsilylated hydrolysate of DNA isolated from the PBMCs of a representative patient entered into this trial before initiation of the doxorubicin infusion. Experimental details are given in “Patients, materials, and methods.” Peak indicates DNA base (ion monitored): 1, 6-azathymine (m/z 256) (internal standard); 2, 5-OH-5-MeHyd (m/z 331); 3, 5-OH-Hyd (m/z 317); 4, 5-OH-Ura (m/z 329); 5, 5-OHMeUra (m/z 358); 6, 5-OH-Cyt (m/z 328); 7, 7a, cis and transThy glycol (m/z 259); 8, 5,6-dihydroxyuracil (m/z 417); 9, FapyAde (m/z 354); 10, 8-OH-Ade (m/z 352); 11, Xan (m/z 353); 12, 2-OH-Ade (m/z 352); 13, FapyGua (m/z 442); 14, 8-OH-Gua (m/z 440).