Detection and characterization of circulating rat mammary tumor cells in buffy coat and correlation with metastasis.

A new method for detecting bloodborne TMT-081 rat mammary tumor cells in buffy coat has revealed dose-dependent variations in the latency period after inoculation of tumor cells, the concentration of circulating tumor cells, and the incidence of metastases. Cells isolated from buffy coat of right ventricular blood were more tumorigenic than tryptically dispersed cells from solid tumors. With the new method circulating tumor cells can be detected at concentrations as low as 3 cells/microliter of buffy coat, or approximately 60 cells/ml of whole blood. The morphologic and ultrastructural features of the primary tumor were generally retained in both the circulating and tryptically dispersed cells, as shown by light and electron microscopy. A sparse distribution of intermediate filaments was revealed by high-voltage electron microscopy, although the filaments were not evident in conventional transmission electron micrographs. They were identified as keratin by immunofluorescence studies.

Nonspecific esterases of leukemia cell lines: evidence for activation of myeloid-associated zymogens in HL-60 by phorbol esters.

Myeloid leukemia cell line HL-60 contains fluoride-sensitive, myeloid-associated isoenzymes of nonspecific esterase that increase in activity when cultures are treated with phorbol ester. These isoenzymes are not detectable in B-lymphoblast cell line KLM-2, either in control or in phorbol-ester-treated cultures. No increased de novo synthesis of the isoenzymes is detectable in HL-60 treated with phorbol ester. The data suggest stimulated conversion of a preformed, myeloid-associated zymogen in HL-60.