[Effect of sodium selenite on tumor cells in culture]

Morphofunctional changes in HeLa cell culture following treatment with various concentrations of selenium ion during 2, 4 and 24 hours are described. Variations in mitotic index, duration of separate mitotic stages and a profile of pathologic mitoses were established. Inhibition of cell entry into the S-phase of mitotic cycle and modifications of RNA and protein synthesis after treatment with 0.1 and 0.25 ppm of the trace element was shown autoradiographically. Increased destruction of cell monolayer following contact with selenium was demonstrated by light, scanning and transmission electron microscopy. It is suggested that selenium exerts a toxic effect on tumor cells although this mechanism is not yet clear.