Immunological properties of the antiserum prepared against the insoluble fraction of GDT-2, a rat ascites hepatoma, have been investigated by indirect fluorescent antibody technique. Results showed that rat tumor antigens were widely distributed in stromal and epithelial elements of normal rat tissues and that the cell surface of rat ascites tumor contained some antigens distinct from that of rat red blood cells, serum, or liver, although the specificity of such antigens was not convincing because of the indication that the antigens were distributed in other organs. Immunological significance of the cell surface and interpretation of some phenomena observed by fluorescent antibody technique were also discussed.

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The chromosome conditions were studied in six cases of venereal tumors of dogs obtained in the city of Sapporo. It was found that the six cases uniformly showed the specific stemline chromosomes having a number-mode of 59. Karyotype analysis revealed that the stemline chromosome-constitution consisted of 17 metacentrics and 42 acrocentrics.
Evidence was presented to show that in one of the present Sapporo cases a shift of the stemline chromosomes had occurred in the late period of tumor growth.

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Twenty-three kinds of inorganic compounds were examined for their inhibitory effect on the MTK-sarcoma III, a rat ascites tumor.
Damages to tumor cells by the influence of these compounds are summarized in a table. Though the degree of influence is not similar in these chemicals, CaCl₂, FeCl₃, FeNH₄(SO₄)₂, ZnCl₂, and ZnBr₂ were found to exert a marked damaging effect on both the cytoplasm and nuclei of the tumor cells. Most cells generally underwent metaphase block by the effect of these compounds, cells being damaged at the metaphase.
Marked decrease of dividing cells was observed in the ascites as a result of repeated application of the chemicals.

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The effect of Mitomycin-C and Carzinophilin, alone or in combination, was investigated from the point of cytology, using HeLa cells in vitro.
Mitomycin-C induced a severe pycnosis in resting cells and Carzinophilin produced changes characterized by a partial agglutination of chromatin, stickiness, and coalescence of metaphase chromosomes. Damaging pattern against HeLa cells is specific to each agent and well distinguishable from one another.

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The increased sensitivity of rat ascites hepatoma cells to nitrogen mustard N-oxide (HN₂-O) by treatment with Tween 80 in vitro was analyzed with ¹⁴C-labeled nitrogen mustard N-oxide (¹⁴C-HN₂O). The transport of ¹⁴C-HN₂O into the parts of cells was studied; whole cells, the fraction precipitated with trichloroacetic acid from the water-soluble cellular protein, and the total of precipitated fraction and water-insoluble fraction in the cells were examined. In the whole cell and fraction the transport was increased by pretreatment with Tween 80. The binding ratio of ¹⁴C-HN₂-O to the cellular homogenate was not altered by the pretreatment.
These results suggest the increased transport of ¹⁴C-HN₂-O into the tumor cells by treatment with Tween 80 which made the cellulr membrane thinner. The significant part of the differences in natural sensitivity of rat ascites hepatomas to HN₂-O seems to depend partially on the different cellular permeability of the drug.

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A protein fraction (S₅-protein) was extracted from Yoshida's rat ascites hepatoma, AH-49. Rabbit antisera against this protein fraction were absorbed with normal rat liver and serum proteins. The precipitin reaction of the absorbed antisera with normal tissue and hepatoma proteins were examined mostly by the technique of Ouchterlony.
The proteins extracted from various tissues of normal rats reacted with the absorbed antisera, but the precipitin lines formed were never identical with the S5-proteins.
The proteins extracted from many strains of Yoshida's ascites hepatoma reacted more or less, but in most cases the precipitin lines formed were clearly distinguished from that of AH-49.
The specific antigenic protein(s) in AH-49 cells was demonstrated mostly in the cell nuclear fraction.
The concept of "the high degree of individuality of the cancer cell" is discussed.

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Histochemical changes in the liver were investigated in tumor-bearing rats, based on sections prepared by means of the section freeze-substitution technique after Chang and Hori.3, 4, 5)
The changes observed were a drastic decrease in the activities of esterase, phosphorylase, and bile-canal ATPase and in the glycogen content, a marked increase appearing in the glucose-6-phosphatase activity and in the amount of basophilic substances (RNA), without any detectable change in the activities of cytoplasmic ATPase, and succinic and choline dehydrogenases.

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Starting from an idea that there must be some reactive intermediate metabolites produced from administered 4-dimethylaminoazobenzene (DAB) in the rat liver (target organ), 4-dimethylaminoazobenzene amine-N-oxide-(DAB-N-O) was prepared chemically and reactions of this compound were investigated, possibly as one of such matabolites. DAB-N-O was found to react rapidly in the presence of iron-porphyrin compounds such as hematin, methemoglobin, etc., yielding a large amount of monomethylaminoazobenzene (MAB), DAB, and 3-hydroxy-4-dimethylaminoazobenzene (3-OH-DAB), and to a lesser extent, 3-OH-MAB, aminoazobenzene (AB), and 3-hydroxy-aminoazobenzene (3-OH-AB). When proteins or amino acids were present in the reaction mixture a part of the dye combined with them, from which similar polar dyes as from liver of rats fed DAB were obtained.

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Toxohormone-like substances were found in the respiration-deficient mutants of Saccharomyces cerevisiae induced by a carcinogenic agent, 4-nitroquinoline 1-oxide. These toxohormone-like substances depressed the liver catalase activity only in vivo, but showed no effect on liver homogenate catalase or on purified bovine liver catalase in vitro.
There was a distinct correlation between the degree of respiration-deficiency of yeast and the production of toxohormone-like factor. There was a significant difference in the activities of toxohormone-like substances of respiration-deficient mutants depending upon cultural conditions.

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