Efficacy of the Frame and Hu mathematical model for the quantitative analysis of agents influencing growth of chick embryo fibroblasts.

The experiments on the effect of various sera and substratum surface area upon growth of chick embryo fibroblast-like cells in secondary cultures are described and discussed on the grounds of a mathematical model for growth of anchorage-dependent cells proposed by Frame and Hu [14]. The model and presented results demonstrate the mutual independence of the effects of agents influencing the rate of cell proliferation (i.e. accelerating or retarding growth) and the agents that modify the limitation of cell proliferation (i.e. maximum cell density at confluence). The model proposed by Frame and Hu due to its relative simplicity offers an easy mode of description and quantitative evaluation of experiments concerning cell growth regulation. It is shown that various sera added at constant concentration significantly modify the rate of cell proliferation with little effect upon the maximum cell density attainable. The cells grew much more slowly in the presence of calf serum than in the presence of chick serum and the addition of iron and zinc complexes to calf serum significantly accelerated cell growth. An increase in the substratum surface area by the addition of glass wool to culture vessels significantly increased cell density per constant volume of medium even when retardation of growth was observed. The results presented point to the need of direct cell counting for estimation of cell growth curves and discussion of effects of agents influencing parameters characterizing cell proliferation.