Application of the microcomputer in multiparametric fluorescence cytophotometry.

Methods for combined cytofluorometric determinations of nuclear DNA plus other parameters (proteins, enzyme activity, or immunoreactive substances) are reported. DNA measurement was performed on an autoradiograph of Feulgen-stained fetal mouse hepatocytes. In order to facilitate the multiparametric measurements and data processing, a fluorescence cytophotometer (BH2-QRFL, Olympus, Tokyo) equipped with four interchangeable filter-sets and controlled by a desktop computer (HP-85F), was used. All data stored in the same computer were displayed in a two-dimensional scatter plot or two-dimensional frequency distribution histogram. Analysis of the DNA histogram of fetal mouse hepatocytes was accomplished by the same computer. Calculated fraction sizes for G, S, and G plus M phases were found to be in good correlation with those determined directly on the simultaneously combined tritiated thymidine (3H-TdR) autoradiography.