This paper describes the results of the cytological investigations on the effects of 2, 5-bis- ethylenimino-hydroquinone (HE) upon the tumor cells of the MTK-sarcoma II, a transplantable ascites tumor of rats.
A single intraperitoneal injection at dose levels of 0.3, 0.4 and 0.6mg/kg was administered to each tumor-bearing rat on the 2nd, 3rd or 4th day after transfer of the tumor.
It was found that HE showed no remarkable effect on the treated animals, since the normal peritoneal cells underwent no visible harmful effect by the drug. But, HE exerted a striking destructive influence on the tumor cells: at 8 hours after injection, tumor cells were completely damaged in most cases studied. Out of 21 tumor-bearing animals received injections of the drug, 19 showed a complete recovery from the disease, having no tumor cells in their peritoneal cavities, leaving two animals in which the chemical application seemed to be unsuccessful.
Most remarkable cytological patterns of the effects of HE on tumor cells were observed as follows:
The deformation and swelling of nucleoli and the reduction in stainability of the nucleus were remarkable in resting cells half an hour after application. The damage of the cytoplasm was also evident by the apperarance of vacuolization and by unusual stainability of cytoplasmic contents. Further, a considerable increase in volume of tumor cells was also remarkable in the course of cellular damage. The tumor cells increased in diameter 2 to 3 times as large as the original size. They were unable to continue division, and underwent disintegration shortly.
So far as the present experiments are concerned, there has occurred no residual tumor stem-cells unaffected by the drug in the peritoneal cavities of treated animals.
In mitotic cells, the drug was found to cause the disintegration of chromosomes. Induced abnormalities of chromosomes leading to their disintegration are striking stickiness, translocation, fragmentation, aggregation and scattering of chromosomes at metaphase, thickening and clumping of chromosomes at prophase, and sticky bridges at ana- and telophase.
In conclusion it is evident that 2, 5-
bis-ethylenimino-hydroquinone seems to exert a radiomimetic action on the tumor cells.
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