Parenteral administration of a single low dose of prednisolone has been shown to exert synthetic influences on nuclear RNA of rat ascites hepatoma cells. Maximal response was attained 4-5 hours after the hormone injection, then the incorporation of ³²P decreased over a 4-hour period, and a secondary gradual increase was observed thereafter. In adrenalectomized rat liver, after hydrocortisone acetate administration, a transition of active incorporation of ³²P from ribosomal RNA to low-molecular RNA within a 6-hour period was observed in the elution pattern of methylated albumin column chromatography. The possibility of the stimulation of enzyme synthesis in hepatoma cells by the administration of glucocorticoids is discussed.

View full abstract

The growth, the estrous cycle, and the reproduction in C3H/He and C57BL/6 strains of mice were investigated mainly from the endocrinological point of view, as a first step in an attempt to clarify the hormonal influence on mammary tumor incidence.
The growth of C3H/He mice was better than that of C57BL/6 mice in either sex, and sexual maturation of the female was earlier in the former than in the latter.
In the pattern of estrous cycle, the pseudopregnant state, i. e., the long diestrous period, occurred more frequently in C3H/He than in C57BL/6, while the slight prolongation of periods of cornification occurred in the latter to a greater extent.
The young weight on the 12th and the 20th days, and the growth rate during the first 12 days of C3H/He mice were larger than those of C57BL/6 mice in most litters. These facts indicated that the former was better than the latter in the lactational performance.
It was concluded that the higher mammary tumor rate in C3H/He than in C57BL/6 may be related to the hormonal conditions which control the natural growth and reproductive cycle.

View full abstract

Effects of Mitomycin-C on various stages of the division cycle of Hela cells were investigated by autoradiography with tritiated thymidine.
Regarding the first division cycle after Mitomycin-C treatment, the latter half of the G₁ period and the first half of the S period of the division cycle seemed to be highly sensitive to Mitomycin-C.

View full abstract

Cancer cases were extracted from a total of 71, 922 autopsy cases (15, 006 cases for 1948-1952, 56, 916 for 1958-1962) obtained from all universities and large hospitals in Japan, and the reliability of the diagnosis was checked. Generally, the reliability of cancer diagnosis in surface organ cancer such as breast, uterus, and rectum is comparatively higher than that in deep organ cancer such as bile duct and gall bladder, liver, and pancreas. During the 10 years of the observation the reliability of cancer diagnosis increased especially in deep organ cancer. Details of misdiagnosis were also described.

View full abstract

Catabolic metabolism of cholesterol in a rat transplanted with Walker carcinoma and the interrelation with β-carotene and ubiquinone were studied in vitro.
Carotene, vitamin A, and ubiquinone are decreased in the liver, and esterified 5α-cholestan-3β-ol and cholesterol are markedly decreased in the adrenal glands and the liver of tumor-bearing rat. The decrease of 5α-cholestan-3β-ol and cholesterol is improved by the addition of β-carotene and ubiquinone.

View full abstract

The spleen foci of Friend's disease, which were proved to be early splenic lesions of Friend's disease, were produced in male DDD mice and in female hybrid, F₁ (C3H/DDD) mice by the inoculation of the diluted virus solution, and were examined by electron microscopy. The major part of the spleen foci in early stages was occupied by tumor cells, which resembled the proerythroblasts or basophilic erythroblasts. The most complex cells, which might be interpreted as immature reticulum cells and considered identical to Friend cells that former researchers had described, showed gradual transition to the proerythroblastic tumor cells. Viral particles were more frequently observed in and around the spleen foci than in other areas, and their budding was seen in all kinds of tumor cells. Even the small, morphologically normal basophilic erythroblasts were observed budding the viral particles. Megakaryocytes near the spleen foci showed irregularly shaped viral particles, suggesting active proliferation of the virus in such early stages.

View full abstract

Repeated experiments using a large number of mice under a long observation period revealed that the final skin cancer incidence was identical when the sequence of application was either 20-methylcholanthrene→croton oil or croton oil→20-methylcholanthrene, as far as the present experimental conditions were concerned. The correlation of the two theories, two-phase theory and summation theory, in carcinogenesis was discussed. It was pointed out that the two-phase theory simply separates the phase of cell cancerization ("initiation") and that of proliferation of cancerized cells ("promotion"), while the summation theory seeks to explain the nature of the process of cell cancerization, need of cell proliferation for the production of clinical tumor being too self-evident to be considered.

View full abstract

Comparative studies were made on the chromosomal condition of tumor cells from the ascites, metastatic lesions in the lungs, spleen, and thymus, and the heart blood of a rat bearing a clonal near-diploid tumor of the ascites hepatoma AH-130 or AH-13. Metastatic tumor cells in the above organs and tumor cells in the heart blood were examined indirectly, using tumor cells which proliferated in ascites of the recipients following intraperitoneal inoculation with those organs and the blood, respectively. Results indicated that the clonal near-diploid tumor, either in ascites or in metastasis and blood, showed a similarity in the chromosomal condition. Increase of polyploid cells in metastatic lesions was not demonstrated.

View full abstract

Hepatic phenylalanine hydroxylase activity and its decrease in response to intraperitoneal administration of tyrosine and tryptophan were studied in rats bearing Rhodamine sarcoma and Walker-256 carcinosarcoma. The effect of toxohormone on phenylalanine hydroxylase (L-phenylalanine, tetrahydropteridine: oxygen oxidoreductase, EC 1.14.3.1) was also investigated.
Hepatic phenylalanine hydroxylase activity in both normal and adrenalectomized rats decreased significantly after intraperitoneal administration of tyrosine and tryptophan. On the other hand, the decrease of hepatic phenylalanine hydroxylase in response to administration of tyrosine and tryptophan was abnormally low both in rats bearing Rhodamine sarcoma and Walker-256 carcinosarcoma, but not in rats with regenerating liver. The phenylalanine hydroxylase activity in both rats bearing Rhodamine sarcoma and Walker-256 carcinosarcoma was the same as in normal rats.
Phenylalanine hydroxylase also did not decrease in response to tyrosine and tryptophan administration in toxohormone-treated rats.
These observations may be interpreted to mean that in tumor-bearing animals there is some disturbance in metabolic regulation which is not dependent on the adrenal glands and this defect is caused by toxohormone.

View full abstract

Using isolated perfused liver of rats bearing Rhodamine sarcoma, hepatoma, or nodular hyperplasia, phenylalanine hydroxylase activity and its response to tyrosine and tryptophan were examined.
In regenerating rat liver, the initial level of phenylalanine hydroxylase (L-phenylalanine, tetrahydropteridine: oxygen oxidoreductase, EC 1. 14.3.1) and its decrease in response to perfusion with tyrosine and tryptophan solutions were the same as in normal rat liver. However, unlike regenerating rat liver, in ethionineinduced hepatoma and in N-(2-fluorenyl)acetamide-inducedn odular hyperplasia, phenylalanine hydroxylase activity was much lower than that of normal liver and the decrease in response to tyrosine and tryptophan was much less.
In host liver, the decrease in response to amino acids was also low, whereas enzyme activity was within the normal range.
These results suggest the existence of a disturbance in the intrahepatic regulation of the level of phenylalanine hydroxylase activity in host liver, hepatoma, and nodular hyperplasia, and a difference between the mechanism causing lower activity of phenylalanine hydroxylase and that causing a decreased response to amino acids.

View full abstract

1. The effect of N, N'-(fluoren-2, 7-ylene)bis-acetylamine (2, 7-FAA) was studied in ICR mice. The animals were fed a semi-synthetic diet containing 0.025% of 2, 7-FAA for 31-34 weeks.
2. The following types of tumors were induced: Adenoma of the liver in 7 cases (8.6%), carcinoma of the liver in 68 cases (84.0%), adenoma of the lung in 18 cases (22.2%), carcinoma of the lung in 2 cases (2.5%), and adenomatous hyperplasia of the glandular stomach in 16 cases (19.8%). Lung metastases from the hepatocellular carcinomas were observed in 3 animals.
3. Only 16 out of 50 of the primary liver carcinomas that were transplanted grew in the first generation. Negative results were obtained with serial transplantation.

View full abstract

Anticancer activities of two derivatives of sulfonic acid esters of aminoglycols, which were proved to be effective against Yoshida sarcoma and some ascites hepatomas, were determined using mouse leukemia L-1210 by the CCNSC screening method.

View full abstract