XXXX @entity45697 @entity11 cells maintained in an organ culture system: a study of kinetic parameters.

@entity1 @entity1950 @entity39 @entity3162 @entity11 @entity1014 @entity35 @entity45697
@entity35 @entity45697 @entity11 cells were grown on a sponge foam matrix in an organ culture system and the cell cycle parameters, including the growth fraction (GF), were assessed after autoradiography. The zones of growth consisted of a compact upper layer (UL) at the gaseous interface, a central @entity39 and a deeper lower layer (LL) which invaded the matrix. The fraction of continuously labeled mitoses (FCLM) was similar in both the UL and LL cells. The derivatives of the FCLM curves obtained in three experiments gave an average modal TG2 of 5 hr. A mathematical model relating GF, TG2, TC and labeling index as a function of time, @entity3162 (t), was devised for cells in a steady state exposed continuously to tritiated @entity1014 and was applied to data obtained from UL cells. A mean GF of 9% (range: 8-10%) and a mean cell cycle time (TC') of 27 hr (range: 13-47 hr) were obtained. The mean @entity1950 was calculated to be 11 hr (range: 8-16 hr) by the method of grain counts per mitotic figure or grain index (GI). Knowledge of @entity1950 permitted alternative calculation of the cell cycle time from the equation Ts/TC = @entity3162 (0)/GF:this gave a mean cell cycle time (TC") of 29 hr (range: 20-45hr). Except for the GF, the cell kinetics were comparable to those of the same cell line grown in monolayer culture. The GF in the in vitro system described is in the lower range reported in some @entity1 @entity11 in vivo.
