Improved BrdUrd‐Hoechst bivariate cell kinetic analysis by helium‐cadmium single laser excitation

Abstract

In laser based flow cytometers, UV excitation of Hoechst 33258 and propidium iodide (PI) or ethidium bromide (EB) is performed with 351/364 rum high power lines of UV‐capable argon ion lasers, which are expensive and short‐lived. In this paper we note for the first time that helium‐cadmium lasers emitting 10 to 30 mW at 325 nm are even more superior for cell kinetic bivariate bromodeoxyuridine (BrdUrd)/Hoechst PI or EB cell cycle analysis. HeCd single laser UV excitation gives comparable CVs for, cell cycle distributions, and almost normal G2D4/G1 ratios of 1.9 to 2.0 for all cell cycles. This is shown for synchronous and asynchronous cell populations on a FACStar+ and an Ortho Cytofluorograf. Therefore we recommend helium‐cadmium lasers as low‐power, cheap, and long‐lived UV excitation sources for the cytochemically simple but high resolution multiparameter BrdUrd‐Hoechst cell kinetic analysis. © 1992 Wiley‐Liss, Inc. Copyright © 1992 Wiley‐Liss, Inc.