Effect of combined misonidazole and d(50)-Be neutrons on a human melanoma transplanted into nude mice.

This paper reports the effect of two different doses (0.1 and 1 mg/g) of misonidazole on the radiosensitivity of human Na 11 melanoma transplanted into athymic nude mice. The mice were irradiated with 50 MeV neutrons. The end point was the in vitro colony-forming assay. Repair of potentially lethal damage following neutron irradiation was comparable to that observed after gamma irradiation. This repair was no longer detectable when 1 mg/g of misonidazole was used. When the 1 mg/g dose was used, the observed enhancement ratios after neutron irradiation were 1.52 for immediate plating and 1.87 for delayed plating. No toxic effect of the drug itself could be detected.