Three hundred and seventy-three surgically resected ulcers of the stomach, comprising both open active and healed inactive ulcers, were histologically examined with close attention on the structural alteration in microscopical appearance in different states of ulcer. In open active ulcers, the histological pictures frequently observed were (1) thick necrotic layer and (2) absence of regenerates, fusion, and granulation tissue. In the healed ulcers, they were (1) presence of regenerates and fusion, and (2) involusion of fibrosis. The results were confirmed by histological examination of 27 ulcers, which had been proved as active or healed by retrospective study of a series of X-ray and gastrocamera films. It is likely that the histological appearance of gastric ulcer may differ according to pendulation from open ulcer to healed ones. The elements of "histological criteria of ulcer-cancer", such as the breach of musculares, fusion, fibrosis, and regenerates, are proved not to be stable and unchangeable findings. It is probable that they can be produced within a short period of time, and that they can disappear within a short time. Presence of these pictures in a gastric ulcer does not always indicate the long standing of the lesion, but merely shows the state of ulcer whether it is inclined toward healing or toward ulceration. These histological pictures, therefore, may not provide any reliable basis for histological criteria of ulcer-cancer.

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The growth of primary fibrosarcomas induced by 3-methylcholanthrene in rats was inhibited by the intravenous injection of spleen and lymph-node cells obtained from allogeneic rats specifically immunized with a heavily irradiated piece of the tumor to be treated. In 12 out of 18 animals (66%), marked slowing of tumor growth or regression occurred without any sign of graft vs. host reaction and effect of the treatment seems to depend on the action of lymphoid cells which were immunized against tumor-specific antigens.
In a series of 14 animals treated with non-immune lymphoid cells, marked slowing of tumor growth and regression occurred in 5 (35%). The non-immune lymphoid cells also caused graft vs. host reaction in some rats, but this did not always occur in association with the antitumor effect.

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Following transplantation of Tawa ascites sarcoma cells into the pulp of the lower incisor of Donryu rats, the "take" was 67.7% and an average survival was 13 days. Gross typical findings consisted of an abnormal occlusion of the incisor and a tumorous swelling of the salivary glands, submaxillary, and cervical lymph nodes. The pulp tissue was subjected to tumorous destruction but the ameloblasts were normal in shape and orderly in arrangement. Phosphorus and calcium in serum and ameloblasts showed no quantitative change but the dental hard tissue and pulp in the tumor cell-transplanted incisor showed a marked decrease in Ca/P ratio due to reduction in calcium content.

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Smoked and dried fish, "Katsuobushi", "Sababushi", and "Urumebushi" which are respectively made by exposing flesh of bonito, mackerel, and sardine to wood smoke for a week or so were analyzed for polycyclic aromatic hydrocarbons. Sixteen hydrocarbons including those with carcinogenic potency were isolated from these fishes by chromatography on alumina column and partially acetylated paper, and determined by ultraviolet absorption spectroscopy. Their concentration was considerably higher than that reported of foreign smoked fishes and other related foods. The amount of benzo[a]pyrene in "Honbushi", "Hanakatsuo", "Sababushi, " and "Urumebushi" was 9, 37 (and 12), 7, and 2μg/kg, respectively.

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By means of RNA-DNA hybridization technique, the RNA populations in rapidly growing rat ascites hepatoma were compared with those of normal rat liver, and definite alterations in the population of RNA molecules in AH-130 ascites hepatoma from that of rat liver were demonstrated.
By the competition experiments using whole cell RNA in RNA-DNA hybridization, it was demonstrated that AH-130 lacked a part of liver RNA's and also synthesized a unique RNA fraction not present in normal liver.
In similar experiment using nuclear RNA, only the deletion of RNA in AH-130 could be found. These different results due to cell fractionation were discussed from the point of selective transfer of messenger RNA from nuclei to cytoplasm and of cytoplasmic gene expression.

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A Leydig cell tumor was found in an inbred W/Fu rat that had been given a thyroid destructive dose of astatine-211. It was studied by transplantation in normal and gonadectomized rats. It was autonomous when isolated. In the earlier passage, the secondary changes in tumor hosts suggested that it secreted predominantly androgens.
After further subpassages, the changes in tumor hosts suggested that it secreted both androgens and estrogens. In males, intact and gonadectomized, there was hypertrophy of prostate and seminal vesicles. In females, there was estrogenization of vaginal epithelium, glandular hyperplasia of uterine mucosa, and follicular cyst formation in ovaries.
Other apparently novel observations were made with this tumor such as inhibition of castration changes in host pituitaries, lobular hypertrophy and hyperplasia of mammary glands in both sexes, and depression of spermatogenesis. This tumor failed to show morphological masculinization of renal glomeruli and of submaxillary glands, and stimulation of hemopoiesis.

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Intestinal metaplasia of the gastric mucosa was examined in 170 otherwise normal autopsy stomachs, and it was revealed that intestinal metaplasia was a common lesion among the Japanese after the age of 40. The results are compared with those obtained from U.S. materials.

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Choriocarcinoma was induced by injection of 7, 12-dimethylbenz[a]anthracene into placenta of fetus left bilaterally after fetectomy. Progesterone was administered intramuscularly once a week for 20 weeks. One out of four rats showed histologically definite choriocarcinoma and another, early neoplastic change after 8 months. Remaining two are under observation.

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Immunotherapy with Friend virus-infected identical tumor cells and chemotherapy with Mitomycin-C against the KMT-68 tumor in isologous rats transplanted 3 days before the treatment were performed. The cure rate of tumors in the combined treatment increased synergistically compared with that in each single treatment.

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The experiments were designed to investigate the effect of lipoprotein lipase on lysosomes fractionated from Yoshida ascites tumor cells in vitro. The lipoprotein lipase used was extracted as a crystal form from Mucor javanicus. It was found that lipoprotein lipase not only labilized the lysosomes but solubilized hydrolases contained in lysosomes.

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During acquisition of resistance by Yoshida sarcoma to alkylating agents, such as nitrogen mustard and No. 838, remarkable increase in total ATPase activity was observed both in plasma membrane and mitochondrial fractions. This kind of increase was also effected by alkylating agents such as cyclophosphamide.

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N-Methyl-N'-nitro-N-nitrosoguanidine was administered to four dogs as dinking water solution for 15 months. They were killed after 518, 593, 698, and 1045 experimental days. All the dogs developed tumors in the cardiac portion and the antral region of the stomach. The tumors were histologically adenocarcinoma of signet ring cell-type carcinoma.

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