Digital image analysis of hematopoietic colonies in vitro.

A system for automatic analysis of in vitro hematopoietic colonies is described and evaluated. With the standard resolution provided by video cameras, the improvement in visualization obtained using features other than size and darkness when classifying potential colonies appears to be limited. We confirmed this by comparing results obtained with the test system with those obtained with a commercial one. However, for some applications it may be useful to supplement the system with specific methods, e.g., to separate merged colonies. Digital image analyses provide new possibilities, for instance of measuring the total cellularity of the dish or analyzing colonies according to the size and cell density of each colony. Examples provided are time course studies of colony development, cellularity feedback effects on colony sizes, and bell-shaped dose-response curves for the growth stimulation obtained by certain conditioned media on a subpopulation of progenitor cells that gives rise to large colonies.