Abstract
Quantitative two-color fluorescence staining techniques, coupled with flow system multiparameter cell analysis and sorting instrumentation, have been used for rapid, simultaneous determination of deoxyribonucleic acid, protein, nuclear (N) and cytoplasmic (C) diameters and N:C ratios in mammalian tumor cells and human gynecologic specimens. Cells stained in suspension for deoxyribonucleic acid and total protein content, respectively, with propidium iodide (red fluorescence) and fluorescein isothiocyanate (green fluorescence), enter a flow chamber and intersect an argon laser beam which excites cellular fluorescence. Optical sensors measure both red and green fluorescence plus the time duration of each fluorescence signal which is proportional to nuclear and cytoplasmic diameters, respectively. The resulting signals are processed and displayed as frequency distribution histograms using a multichannel pulse height analyzer. Cells are also sorted based on N:C ratios. Illustrative examples of preliminary two-color fluorescence analysis and sorting of mouse squamous tumor cells and human exfoliative vaginal cells are presented.