Utilizing the method of injecting tissue homogenate for a rough estimation of relative toxohormone content, we first found that toxohormone content of tumor tissue can be markedly increased by injecting protein hydrolysates into animals bearing the tumor. It was then determined, by testing the effect of various amino acid mixtures, that eight specific amino acids were essential to this effect. These amino acids were: Alanine, proline, aspartic acid, arginine, phenylalanine, lysine, leucine, and glutamic acid.
The findings were interpreted as indicating that these amino acids may be the major components of toxohormone, and that the increase in the toxohormone content may be due to the supply of extra quantity of the material for the synthesis of this unique toxic product of tumor cells.
The "normally" low toxohormone content of the strain of tumor and the protein sub-deficient nature of the diet used in these experiments were pointed out as possibly important factors in revealing the role of the specific amino acids in toxohormone synthesis.

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[in Japanese]

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[in Japanese]

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The process of the "amitosis" was studied with Yoshida sarcoma cells. Shapes of amitotic nuclei demonstrated in the smear preparations were classified into four groups: dumb-bell shape, lobed shape, one-side-furrowed shape, and bud-sprouting shape. Among these, only in dumb-bell shaped nuclei it was confirmed that they could completely divide and present two or three separate nuclei. This was certified further by phasemicroscopic observations in the living condition.
Special attention was paid for the examination of cytoplasmic division following after the amitotic or direct nuclear division. However, it was demonstrated that any cytoplasmic division followed after a direct nuclear division neither in the smear preparations nor in the living condition of cells under the phasemicroscope. Therefore, it is a conclusion of present studies that the so-called amitosis does never contribute to cell multiplication, though it can bring about, only in rare cases, polynucleate cells.

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[in Japanese]

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Two cc of 0.25M CaCl₂ solution, 1cc of 0.125M AlCl₃ solution, or 1cc of 2per cent H₂O₂ were injected into the peritoneal cavity of the tumor-bearing rats of ascites sarcomas, and the effects of these chemicals were investigaled with smear preparations made at various intervals after injection of the chemicals. It was found that these chemical first exerted their influence on the cytoplasm, invariably inducing the breaking down of the cell body of the tumor cell. Then the pycnotic disintegration of the resulting naked nuclei followed. There occurred a temporary retardation of growth of the tumor to greater or less degree in every experimental animals as a result of damage to the majority of the tumor cells by the application of these chemicals, but a certain number of the resistant tumor cells always remained unaffected by the chemicals applied, so long as the dosage employed was sublethal to the host. Upon cessation of the action of the chemicals, these resistant tumor cells began multiplication and caused the renewed growth of the tumor in the treated animals. There is a great need to study the physico-chemical properties of these. resistant tumor stem cells in connection with cancer chemotherapy.

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