ENHANCEMENT OF THERMAL KILLING BY POLYAMINES .3. SYNERGISM BETWEEN SPERMINE AND GAMMA-RADIATION IN HYPERTHERMIC CHINESE-HAMSTER CELLS

When combined with heat the polyamine, spermine, enhances the synergistic interaction between hyperthermia (42°C) and γ radiation in cultured Chinese hamster V79 cells. The enhanced radiation response is reflected in reduction of both D(o) and D(q) of the survival curves. The shape of the fractionated survival curves indicates that a small heat dose plus spermine is as effective as a large heat dose without spermine in inhibiting the repair of radiation-induced sublethal damage. In addition, spermine also potentiates the effectiveness of heat in inducing transitory thermal resistance. It thus appears that polyamines amplify all the effects of heat that have been so far tested on the cellular level.