A Technique for Locating Rare Cells in the Circulation for Ultramicroscopy1

A method has been developed for the isolation of rare cells in heterogeneous cell suspensions, for ultramicroscopic examination. Such cells cannot be located using conventional embedding screening techniques. The cells are embedded in Epon which is polymerized in the shape of an ordinary glass slide. Large numbers of suspended cells may be screened by light microscopy for the rare cells, which may then be sectioned for ultramicroscopy. The method has been used to locate and ultramicroscopically identify circulating endothelial cells in the blood of patients and experimental animals.Although artifacts were induced by the techniques used for collecting and concentrating circulating endothelial cells, the embedding method itself did not cause further morphological alterations.