[Exponential growth of cell numbers. II. Cell death immediately after mitosis]

A mathematical model was examined of the exponential growth state of the cell number (N) with the proliferative pool Pc greater than or equal to 1, the non-zero variability of the phase duration of the mitotic cycle and with the cell death immediately after mitosis. At this state it is impossible to calculate the cell loss factor phi from Steel's formula (1968). A method was proposed for calculation of phi, Pc and the potential doubling time (tDpot) of N (and the mean duration of mitosis, tM), provided the doubling time of N, the indexes of S- and M-phase, the mean durations of mitotic cycle and of S, G2- and M-phases (or G2 + 0.5 M)-phase) are known from experimental data. The approximate values of phi, Pc, tDpot and tM were calculated for six solid transplanted tumors. It is noticed that using this mathematical model the cell kinetics was described satisfactory for not all the tumours examined.