[Autoactivation in cell populations].

A mathematical model of cell population with cooperatively controlled mitotic activity is analysed. The mitotic activity of stem cells is activated by the cells themselves and is inhibited by differentiated cells. Analysis of the model shows that steady-state oscillations in the mitotic activity are possible in such populations. The appearance of self oscillations is due to a delay in the negative feedback loop. The oscillation period, determined to a linear approximation, is greater than a quadruplicate delay.