A model for cell killing by continuous heating

Based on an analysis of cellular survival curves following single heating, a model is proposed to explain the action of heat on cell survival. The basic idea of this model is that cellular inactivation by heat is a three-step process. In the first step, heating produces sublethal damage. Secondly, the produced damage is repaired in a certain time period after the cell has received it. The time period to be required for repairing the sublethal damage changes with the thermal conditions that the cell has undergone. In the third step, the lethal event is induced when the cell undergoes cumulative sublethal damage to the extent that it cannot be repaired. The incidence of sublethal damage is calculated using the Arrhenius equation, where one inactivation energy is postulated. Based on the assumption that sublethal damage occurs at random, a mathematical model has been worked out that quantitatively describes cell killing by single heating. This mathematical model has been applied to the surviving fractions of Chinese hamster ovary cells reported by Sapareto, and it correlates to the whole surviving data at a temperature range of from 41.5 to 46 degrees C by the substitution of the appropriate values for the parameters of the model.