Determination of Cell Kinetic Parameters

Abstract

Although the basic models of population growth apply to cells as well as to animals and men, the methods used to determine kinetic parameters are quite different in the two areas. In demography and partly in population biology the parameters (e. g. mean life span) are obtained by observations on a certain number of individuals at several stages of their life or during their whole life. But it is impossible to pick up any individual cell in vivo and perform subsequent observations on it. This difficulty in the study of cells however is compensated for by the possibility of observing at any given time a great number of cells and of performing experiments. Observing a great number of cells allows the determination of certain phase indices, and then the relative duration of these phases can be calculated with appropriate formulae. More information is supplied by the observation of synchronous instead of asynchronous cell populations. Synchronization can be achieved by special experimental techniques (see the survey by Nias and Fox, 1971) or by selection of a synchronous subpopulation (e. g. by labelling cells in S-phase). Since the phase indices of synchronous cell populations are varying, samples of the population are taken and prepared for inspection at different times during the course of the experiment. If in a study in vivo only one sample can be taken per animal, then the samples have to be taken at different times from different animals which have received the same treatment. Each sample reflects the state of the population at the time when it was taken, and thus it is possible to draw curves of the observable quantities over time. In the analysis of these curves mathematics are very helpful.