Propidium iodide staining of cytoautoradiographic preparations for the simultaneous determination of DNA content and grain count.

A new method is described for staining cell nuclei with propidium iodide in preparations that have been processed for autoradiography. The permeability of the stripping film to the dye molecule has been studied, as have the staining conditions, in order to optimize the stoichiometry of the DNA-dye interaction. A procedure has also been set up to allow the simultaneous measurement of DNA content and grain count on the same cell.