A substance which reacts specifically with thiobarbituric acid and produces a red color was isolated from normal rat livers, and it was identified as choline-containing acetal phosphatide. This lipid was soluble in ethanol, not precipitated from ethanol extract with CdCl₂, extractable from CdCl₂-treated ethanol solution with chloroform, and precipitated from petroleum ether solution with acetone. Since it has been known that this TBA-reaction is absent from the tissues in which cell proliferation is actively taking place, especially in tumors, the present findings concerning the nature of TBA-reacting substance are not without interest from the viewpoint of cancer research.

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Normal tissues, such as rat liver, lung, heart muscle, and small intestine, were found to contain considerable amounts of choline plasmalogen. In rat primary hepatoma, ascites hepatoma and fibrosarcoma also, choline plasmalogen is contained in appreciable amounts. However, it was found that the iodine number of this lipid was always very low in the case of these tumor tissues as compared with that of the lipid isolated from the homologous normal tissue, indicating that the lipid is undergoing a profound change in the degree of unsaturation and is no longer capable of showing TBA-reaction.

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1. The influence of hypophyseal factors on liver catalase level of tumor-bearing animals was examined, using male and female albino rats bearing fibrosarcoma as material. Catalase activity was measured by the two methods; the iodometric titration and the manometric method.
2. Although the liver catalase activity was two to three times as high in the hypophysectomized rats as in normal controls, it was found to be reduced to normal level by the intraperitoneal administrations of 25 or 50mg of beef anterior pituitary (as crude acetone powder in saline suspension). A similar result was also obtained with the daily dose of 0.2mg of pure growth hormone for 5 days.
3. The liver catalase activity in hypophysectomized animals was not decreased at all in spite of the presence of a growing tumor. However, the depression of liver catalase activity was invariably observed in hypophysectomized-tumor-bearing animals when growth hormone was administered (daily dose of 0.2mg for 5 days).
4. The present data suggest that the catalase depressing factor produced by tumor may act through some of the hypophyseal factors and that growth hormone plays an important role in the regulation of liver catalase level, whether in normal or tumorbearing animals.

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1. An attempt was made to examine whether or not some hypophyseal factors is involved in the control of liver catalase level in tumor-bearing mice, male hybrid mice being used, and hypophysectomy performed with parapharyngeal approach. Catalase activity was estimated by the two methods; iodometry and manometric method. As a transplantable tumor, Ehrlich acsites tumor was used.
2. Hypophysectomy does not increase the liver catalase level in the case of normal mice as opposed to the case of rats. In the hypophysectomized-tumor-bearing mice, however, there was found no increase in liver catalase level in spite of the presence of growing tumor, although in the case of mice with hypophysis intact or with incomplete hypophysis, there was a considerable reduction of liver catalase level as a result of tumor transplantation.
3. The result suggests that hypophysis is indispensable for the reduction of liver catalase in tumor-bearing animals.

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Twenty different strains of the rat ascites hepatoma were used in the present study, in an attempt to find whether, by means of comparison of the X-ray dose necessary to kill 10⁷ tumor cells of each tumor strain, the individual difference in radio-sensitivity existed among these tumors which were naturally all common in the normal ancestral cell, the liver cell; and if it existed, to know what biological characteristics of tumors it was related to. The results obtained are as follows:
1) Even the tumors derived from one and the same ancestry never did agree with each other in their radiosensitivity.
2) The radiosensitivity of tumors is related to their growth velocity. The slower growing tumors are more radiosensitive than the faster growing tumors. This result does not support Bergonié-Tribondeau's law.
3) X-radiation induced more remarkable damages in the tumors showing more marked polymorphism of cells than in the tumors consisting of uniform cells.
4) No correlation was found between the radiosensitivity of tumors and the sensitivity of them to HN₂ derivatives.
[The major points of the present study have been reported in the 17th General Meeting of the Japanese Cancer Association, Chiba, Japan, November 9, 1958 (12)].

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Chromosomal conditions in a human gastric carcinoma treated with Carzinophilin were observed in the present study. Distribution of chromosome numbers in four successive samplings showed a wide range of variation from hypodiploidy to above octoploidy. Various chromosome abnormalities were produced, especially in highly ploid cells.
In every sample observed here, the chromosome-number distribution was characterized by a marked mode at 62. It seems probable from the above evidence that the stemline cells with 62 chromosomes have remained unaffected by the drug, maintaining their individuality through the Carzinophilin-treatment.

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In the present study the change in strain specificity and transplantability was investigated in the MY-mouse sarcoma in relation to the alteration from diploidy to tetraploidy of stem-cells.
In early transplant generations, the present tumor was transplantable to mice of SMA, DM and some other strains and characterized by stem-cells of a near-diploid complex. On the other hand, this tumor failed to grow in mice of C3H, DBA/Ma, A, SWR and Swiss albino which were imported from the United States. After the 94th transplant generation, this tumor became transplantable to mice of various strains such as DM, D103, SMA, S4, SK, SL, SF, C57L, C57BL, C58, DBA/Ma, C3H, A, SWR, Swiss albino, sps, dd and dba. At the same time the tumor stem-cells showed a change in chromosome number from near-diploidy to near-tetraploidy. Morphological analysis of chromosomes revealed that the near-tetraploid cells seemed to be derived from near-diploid cells through the mechanism of chromosomes duplication. The evidence obtained indicates that changes have occurred in the stemline chromosomes in association with changes in tumor properties during serial transfers.

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The electronic structure of methyl-substituted 1, 2-benzanthracenes, heteroaromatic compounds such as benzcarbazoles, benzacridines and DAB derivatives was calculated by the frontier electron method. A distinct parallelism was found between the frontier electron distribution at the carcinogenophore of these compounds and their carcinogenic activity, Reaction involved in the early stage of carcinogenic action of all chemical carcinogens has been postulated by the present authors to be of nucleophilic nature, and the numerical values of the reactivity indexes in this paper supprt this postulation.

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Isonicotinic acid hydrazide (INH), a tuberculostatic or tuberculocitic compound of wide use, induced pulmonary tumors when it was fed to mice with diet. Under the usual conditions of our experiments multiple pulmonary tumors were engendered in high proportions of animals surviving 7 months. Two months of feeding of INH are sufficient to induce pulmonary tumors in 60 per cent of animals whithin 7 months. The pulmonary tumors induced by INH feeding are apparently initiated by the hyperplasia of the alveolar epithelium and could be classified as adenomas identical in appearance with the spontaneous pulmonary tumors that occur in the strain.
A few substances related to INH, namely pyrazinamide, Neoiscotin, and semicarbazide, also produce pulmonary tumors. All these compounds have carbamyl groups in their chemical structures.

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When INH was added at the level of 0.1 or 0.2 per cent to 0.04 per cent DAB diet, the liver cancer production due to DAB at the 150th day was markedly inhibited. The possible inhibitory mechanism of INH for azo-carcinogenesis was discussed but leaves much to be investigated in the future.

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1. The cigarette tar was collected from a total of 3, 500 cigarettes of popular Japanese brand PEACE, smoked in the usual way by the people through glass wool filter held in a special glass cigarette holders.
2. The tar has been extracted and the neutral extract in cyclohexane has been examined by chromatography followed by ultraviolet absorption spectrophotometry.
The amount of pyrene and anthracene were calculated as 1.06μg/100 cigarettes and 3.06μg/100 cigarettes respectively.
3. 3, 4-Benzpyrene was not detected in the tar.
4. Possible causes for the failure in detecting the important carcinogen and for low values obtained of other hydrocarbons are discussed.

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1. Correlative histochemical and autoradiographic study was made on the keratinization in the experimental epidermal tumor, hyperplastic epidermis and normal keratinizing tissues.
2. No essential qualitative difference was noticed between the epidermal tumor and normal keratinizing tissues.
3. The grade of differentiation of the epidermal tumor may be regarded as expressed in the grade of keratinization of its cells.

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1) Acetone and ammonium sulfate fractionations were carried out on the rats liver homogenates administered with 3'-Me-DAB.
2) The starch zone electrophoretic patterns were compared among the supernatants of rats liver homogenate fed carcinogenic 3'-Me-DAB and non-carcinogenic 2-Me-DAB or AB. No significant difference was observed in the patterns but the amount of the protein bound dye was greater with the carcinogenic azo dye than with the noncarcinogenic ones.
3) At least three protein groups responsible for the dye binding seem to exist in the supernatant from the electrophoretic pattern. The general impression from the comparison of the electrophoretic pattern of the bound dye with that of the protein, however, does not support the presece of any specific protein responsible for the binding but may indicate more or less random binding, even though not completely evenly among the various kinds of liver proteins.

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