“…Kinetic studies of oxidative enzyme systems in living cells have been made by microfluorimetry, utilizing the fluorescence of reduced pyridine nucleotide (Chance and Thorell, 1959;Chance, 1962;Kohen and Kohen, 1966). Rotman and Papermaster (1966) observed that living cells in a medium containing certain fluorescein esters of fatty acids became fluorescent.…”