Patients were randomized to receive cisplatin 50 mg/m2 or the same dose of cisplatin plus mitolactol (C + M) 180 mg/m2 orally on days 2 to 6

Calf thymus DNA (64mg) in 0.25M sodium cacodylate buffer, pH 7.10 (3 ml) and dibromodulcitol (Mitolactol) (308 mg: 1 mmol) in dimethylsulphoxyde (3.5 ml) were mixed and the reaction was allowed to proceed for 2 days at 37°C. The alkylated DNA was then dialysed against 0.01 M Tris-HC1 (pH 7.0) and 0.01 M NaC1 at 4°C for 48 h and hydrolysed at pH 1 for 30 min at 70°C. The pH of hydrolysate was raised to 10.8 prior to chromatography on a column (2.6 cm × 32 cm) of Sephadex G-10. Elution was performed with aq. NH3 pH 10.8 collecting 6.5ml fractions. Four major UV-absorbing peaks were found of which fractions 10-17 contained oligopyrimidine-nucleotides, fraction 19-21 7-alkylated guanines (A2s0/A26o:l.7), fractions 23-29 guanine (A2s0/A26o:l.1) and fractions 33--44 adenine and 3-alkyladenine together (Aes0/A26o:0.36). 7-Alkylguanine derivatives were separated by rechromatography on a column (17 cm x 1.2 cm) of DowexS0 W (H + form) using 1 M HC1 as eluent, 6.5 ml "fractions were collected.