Measurement by Quantimet 720 of the proportion of actively growing cells in tissue cultures of human lymphocytes.

The size-distribution of normal human lymphocytes growing in tissue culture was measured with a Quantimet 720 image-analysing computer. The proportion of cells undergoing volumetric growth after phytohaemagglutinin (PHA) stimulation was dervived from a simple mathematical model describing the growth patterns of the cells up to the first mitotic division. The approach may have general application in biology as a method for measuring the proportion of growing cells by microscopy.