Localization of plasma proteins in the Walker carcinosarcoma of rats was studied by the use of ¹³¹I-labeled plasma proteins. Among the plasma proteins tested, lizing activity of ¹³¹I-fibrinogen in the tumor tissue was closely related to the growth or development of tumor after implantation.
Localizing activity of fibrinogen or chemically modified fibrinogen seemed to be closely related to its clottability. When clottability of fibrinogen was remarkably decreased or lost by some chemical modifications, the higher localizing activity in the tumor tissue was also lost.
With regard to its localization among subcellular fractions of tumor, ¹³¹I-fibrinogen was found to be accumulated predominantly as an insoluble form in the sediment of 900g for 10 minutes. It was suggested that fibrinogen localized in tumor tissue as fibrin.
On the other hand, thromboplastin activity of tumor tissue was at the same level as the normal lung tissue and it was found mostly in microsomal fraction of tumor cells, thus high thromboplastin activity of tumor cells might play a rôle in converting fibrinogen to fibrin, resulting in the unusually high localization of fibrinogen in the tumor tissue.

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Comparative studies were made on cellular sulfhydryl content and other biochemical properties in three strains of Yoshida ascites hepatoma of the rat which have been known to have different sensitivity to X-rays and nitrogen mustard N-oxide.
The sensitive strain (AH-130) had a longer mean generation time than the resistant strains (AH-7974 and AH-130R). Effects of X-irradiation on mitosis and mitotic cycle were found to be greater in the sensitive strain than in the resistant strains.
Activities of several enzymes of the sensitive strain were found to be different from those of the resistant strains, indicating the difference in cell origin or cell population of these hepatoma strains. Alkaline phosphatase was remarkably high in the sensitive strain. dCMP deaminase was not detectable in the sensitive strain while it was present in the resistant strains. Patterns of LDH isozymes on the polyacrylamide gel electropherogram in the sensitive strain were also different from the resistant strains.
The content of non-protein SH was found to be lower in the sensitive strain than the resistant strains, whereas that of apparent protein SH was higher in the sensitive strain than the resistant strains. Activity of glutathione reductase was lower and that of glucose-6-phosphate dehydrogenase was higher in the sensitive strain than in the resistant strains, indicating the difference in the regulatory mechanism of cellular sulfhydryl level in these hepatoma strains.

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An attempt was made to induce a bronchial carcinoma similar to that of human in the mucosa of main bronchus of the rabbit by repeated intrabronchial application of 3-methylcholanthrene through a specially equipped bronchoscope.
1) A strikingly high incidence of squamous metaplasia occurred in the bronchial mucosa. Eight rabbits (approximately 7%) showed an invasion of atypical squamous epithelium into the submucosa. Similar changes in the terminal bronchi and/or alveolar walls were observed in 7 rabbits (approximately 6%). On the other hand, 4 rabbits developed adenomatous proliferation in the submucosa. These histological features seemed to be indistinguishable from those of carcinomatous changes found in human, though no metastases occurred in these rabbits.
2) Combination of the subcutaneous injection of 4-nitroquinoline 1-oxide with the intrabronchial application of 3-methylcholanthrene was confirmed to be more effective in inducing the carcinomatous changes on the bronchial mucosa.
3) Applications ranging approximately from 30 to 70 times were found to be most effective in carcinogenesis, but more than 100 applications caused injury of the bronchial mucosa which resulted in less incidence of carcinomatous changes.
4) Approximately 60% of the animals developed systemic amyloidosis of rabbits which had undergone the intrabronchial 3-methylcholanthrene over 50 times.

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Myxoma of the heart, found in an autopsy case of 38-year-old female, was investigated histologically, histochemically, and electron microscopically. In the left atrium was observed a polypoid tumor, 5cm in diameter, attached to the interatrial septum by a short slender stalk. It exhibited the typical histological picture of myxoma, and was not indicative of organization of thrombi. On account of following findings, this myxoma was considered to be derived from embryonal undifferentiated mesenchymal cells: (1) Myxomatous tissues were also present in the muscular layer of the interatrial septum, (2) hematopoietic foci were observed in the tumor tissue, and (3) a few cross-striated tadpole-shaped cells characteristic of embryonal botryoid rhabdomyosarcoma were encountered.
The nature of the myxoma was discussed especially with regard to its relation to embryonal botryoid rhabdomyosarcoma.
The interatrial septa were histologically investigated in eleven autopsy cases of newborns and infants, and the presence of myxomatous tissue was confirmed.

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Studies were made on the effect of thymectomy at 3 days of age on mammary tumorigenesis in the mouse using F₁ hybrid females of (C3H/HeMs×129/J) constitution carrying Bittner virus. Removal of the thymus resulted in a decreased incidence of mammary tumors and hyperplastic alveolar nodules, preneoplastic lesions. This was associated with the poor development of mammary glands which was also observed in virgin females of (129/J×C3H/HeMs)F₁ hybrid of low mammary tumor incidence. Experiments on (C3H/HeMs×129/J)F₁ females treated with estradiol benzoate for 4 months yielded the same results. Experiments on C3H/HeMs mice, thymectomized at 40 days of age, treated with estrogen, showed similar data. Ovaries and uteri showed hypoplastic and/or regressive morphology in the thymectomized mice. These results indicated that the inhibitory effect of thymectomy on mammary tumorigenesis was mediated by deficiency in noduligenesis and further, probably, in mammogenesis.
The nature of reduced mammary tumorigenesis following thymectomy was discussed and it was suggested that endocrinological mechanism might be involved.

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In continued attempt to clarify the mechanism of host-mediated action of the polysaccharide of bagasse (pressed residue of sugar cane) on subcutaneously implanted sarcoma-180, observations were made on the immunological response in mice comparing the polysaccharide-treated and non-treated mice. It was found that the ability to produce antibody against sheep erythrocyte and phagocytic capacity for carbon particles were not influenced by the administration of this polysaccharide. Rejection of skin homografts in bagasse polysaccharide recipients seemed to be not accelerated.
The sera from the mice in which tumors regressed under the bagasse polysaccharide treatment showed a marked antitumor effect when administered after implantation of the tumor. A significant increase in hemolytic activity and decrease in anticomplement activity in the sera of polysaccharide-treated mice were observed.

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The levels of six glucose-metabolizing enzymes in LY-336, a slow-growing variant subline of Yoshida sarcoma, were compared with those in the parent tumor and AH-130, a rat ascites hepatoma. In agreement with the previous finding that LY-336 has the highest glycogenic capacity, the levels of glycogen synthetase and phosphoglucomutase in this tumor are much higher than in other two tumors. Furthermore, of the three tumors, only LY-336 contains a measurable quantity of fructose diphosphatase. The levels of catabolic enzymes such as glycogen phosphorylase and phosphofructokinase are not markedly different among the three tumors.
Glycogen synthetase, phosphorylase, and fructose diphosphatase of the tumors differ in certain respects from the respective enzymes of rat liver. The glycogen synthetase of tumors is activated by glucose 6-phosphate to a much smaller degree than the liver enzyme. The response of the tumor phosphorylase to AMP is much higher than that of the liver enzyme. The fructose diphosphatase of LY-336 is inhibited by AMP to a much greater degree than the liver enzyme.

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N-Demethylations of dimethylnitrosamine (DNSA), p-(dimethylamino)azobenzene (DAB), N-nitroso-N-methylaniline (NSMA) showed clear sex difference. Phenobarbital increased N-demethylation of DAB and NSMA in male and female. Methylcholanthrene increased DAB N-demethylation in male and female, but it increased NSMA N-demethylation only in female rats and decreased DNSA N-demethylation in male and female.

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Reports on the outbreak of leukemia have come to attract considerable attention recently. In Shizunai, 12 cases of leukemia occurred in the past 4 years. Especially for the 12 months between September 1965 to August 1966, the rate of incidence per 100, 000 population was 28.0. This is statistically a risk rate of below 0.1% (t>1.84) which is clearly high.

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A transplantable strain of mouse tumor derived from a spontaneous endometrial growth is described. It has certain histological peculiarities, most especially the production of large amounts of hyaline substance. It readily takes the ascites form and the strain can be conveniently maintained in that form. The ascites is characterized by the suspension in it of hyaline particles and the rosette formation of the tumor cells.

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Pleomorphic clones of Tetrahymena pyriformis var. I, mating type IV, induced by a potent carcinogen, 4-nitroquinoline 1-oxide, were conjugated with the normal mating type III. Isolation cultures of the hybrids after mating revealed that the hybrids showed normal nuclear behavior at division, suggesting that the pleomorphism may be a genetically recessive character.

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More striking effect of histidine was observed than any other amino acid on ⁶⁵Zn uptake by Ehrlich cells in vitro; the minimum uptake of radioactivity in saline and the maximum in ascites fluid-added medium. No significant difference was found between L- and D-isomers of amino acids.

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O, O'-Diacetyl-4-hydroxyaminoquinoline 1-oxide was synthesized from carcinogenic 4-hydroxyaminoquinoline 1-oxide. The structure was established by NMR and IR spectroscopies. This compound is expected to be of help for correlating the carcinogenic mechanism of quinoline derivatives and other carcinogenic compounds.

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Two strains of the transplantable tumors, which originated probably from upper jejunum of male Buffalo rats fed a basal diet containing 0.025% N, N'-2, 7-fluorenylenebisacetamide for seven to nine months, are described.
The original tumors had histological pictures of poorly differentiated adenocarcinoma rich in signet-ring cells and showed infiltrative growth on the peritoneal surfaces. Metastases into the lymph nodes were also found.
The transplantation rates of both strains were 100% for several generations but after the 7th generation, the transplantability was reduced. In one tumor strain, successive transplantation failed at the 11th generation. The rats which received subcutaneous inoculation of another strain most recently also has not developed any palpable tumors for the last five months.

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