A Study of Morphological Changes in the HeLa Cells by Irradiation, with Particular Reference to Judgment on Prolif erative Cell Death from Enlargement of Nucleus

Abstract

The following conclusion was drawn as result of irradiation of various dosage of radioactive rays, once each time, on the HeLa S3 cell.
1. The number of cells decreases with irradiation, but the tendency of decrease differs according to radioactive dosage. Under 500 rad, the cell was observed to restore to its former condition and even at 1, 000 rad, its existence was still recognizable. But over 2, 000rad, its capacity of infinite multiplication was almost denied.
2. As for the transformation of the cell nucleus, an increase and enlargement was observed. The rate of emergence of increased nuclei was relatively high in the mid-range dosage group (500-1, 000rad). The enlargement of the nucleus showed a difference according to irradiation dosage, and followed a similar tendency as in No.1 so that restoration to its former condition was not observable over 2, 000rad.
3. The enlarging speed of the large-scale nucleus cell of more than 25μ was almost the same, regardless of amount of irradiation dosage.
4. Through this study, we found out that the decrease of the number of cells, nucleus enlargement, and the rate of existence obtained by empirical formula coincide with each other, and that there is a close relation among them. At the same time, we became confident that it is possible to infer the radioactive effects from clinical examination of the nucleus enlarging phenomenon.