“In culture, 6-aminonicotinamide potentiated the cytocidal effect of BCNU; however, it did not … effects of nitrogen mustard or gamma-irradiation in vivo, both 6-aminonicotinamide and nicotinamide potentiated … of BCNU ; however, the concentrations of nicotinamide required for this effect …- to 20-fold higher than those of 6-aminonicotinamide.”