A rapid method for accurate DNA measurements in single cells in situ using a simple microfluorimeter and Hoechst 33258 as a quantitative fluorochrome

A method is described for the rapid, accurate measurement of single cells in situ using microfluorimetry. This method involves a shutter system, which allows irradiation of single cells for fractions of a second and a peak fluorescence intensity recording device. In this way errors due to fluorochrome fading are almost eliminated and standard deviations of less than 5% are obtained. Hoechst 33258 has been used as a quantitative fluorochrome. Optimum fixation and staining conditions on glass and plastic tissue culture vessels are described.