Application of flow cytometry in chronobiology

A survey is given on flow cytometric techniques and their applications in chronobiology. Rapid automatic single cell measurements with a high rate (1,000-5,000 single cells/sec) enable the accumulation of large numbers of data at short intervals, thus obtaining important knowledge on circadian variations of cell proliferation in epidermis and other types of surface epithelium as well as hemopoiesis. In addition, the method has to some extent been used for monitoring cancer chemotherapy, and is thus available for the application in chronotherapy of malignancy. The introduction of rapid automatic techniques such as flow cytometry is a great advantage for any study on single cells and tissues where rhythmic variations in different functions have to be taken into consideration.