GRAIN COUNT DISTRIBUTIONS IN LABELED CELL POPULATIONS

A quantitative mathematical formalism for the grain count distribution in radio-autographs of cells prepared at various times following exposure to radioactive thymidine is developed. The theory is formulated in the context of a particular model of cell proliferation proposed by Lajtha. The connection between the distribution of tritium atoms among the cells calculated from the theory and observable quantities such as the labeling index, median grain count, etc., are worked out in detail. Various possible extensions of the model are discussed and these appear to be sufficiently flexible so that they would correctly represent observations such as those of Clarkson and others on leukemic myeloblast cell populations. The time evolution of this cell population following an arbitrary initial state is also presented. © 1969.