The activities of enzymes involved in glutathione metabolism (γ-glutamyl transpeptidase, glutathione peroxidase and glutathione reductase) were assayed in rat liver during carcinogenic azo dye feeding. Reduced and oxidized glutathione levels were also determined in relation to the above enzymes. The level of γ-glutamyl transpeptidase changed markedly by the azo dye feeding; the activity increased in early stage and then decreased, and again increased in late stage. The activity in the hepatoma that developed was 40 times higher than that in the normal rat liver.
Changes in the ratio of glutathione peroxidase activity to glutathione reductase activity and the ratio of oxidized glutathione level to the total glutathione level (oxidized glutathione plus reduced glutathione) were calculated throughout the process of azo dye feeding. The activity ratio increased to a value 2-3 times higher than that of the normal liver in 1-3 days of azo dye feeding, then decreased until the 70th day, followed by rise to a maximum at about the 140th day. In the induced hepatoma the ratio of the enzyme activities was close to the values of 1-1.5. This suggested the effective coupling of these enzymes in hexose monophosphate pathway in the hepatoma tissue against those of the normal rat liver. The ratio of oxidized glutathione level to the total glutathione level was very low in the hepatoma tissues compared to the normal rat liver.

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Buffalo strain male and female rats, 12 weeks of age, were given 0.04% N-4-(4'-fluorobiphenyl) acetamide in a semi-synthetic diet for 36 weeks and allowed to live for 12 additional weeks on a basal diet without the chemical. Carcinomas of the kidney were observed predominantly in male rats. Carcinoma cells histologically had basophilic cytoplasm varying from darkly to lightly staining, as well as clear cytoplasm. There was also focal scarring of distal tubules and cysts.
These carcinomas resemble renal carcinomas in human beings since they are similar grossly and histologically, and develop predominantly in male rats. This model in the experimental animal will be useful for studies concerning carcinogenesis of the kidney.

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The effect of several therapeutic procedures on tumor immunity was compared on three lines of syngeneic tumor grafts of primary or early transplant generation in a group of mice previously sensitized with BCG or xenogeneic cells and in that of nonsensitized mice. For immunotherapy, a mixture of syngeneic tumor cells with BCG, tuberculin purified protein derivative (PPD), xenogeneic cells, or allogeneic cells was inoculated intradermally. For chemotherapy, cyclophosphamide or Mitomycin-C was given peritoneally twice a week for 8 weeks after the intradermal tumor inoculation. When intradermal tumor size became 5-13mm in diameter the established tumors were surgically excised.
1) Immunotherapy using intradermal inoculation of the tumor cell-BCG mixture resulted in significant suppression of tumor growth (49/60) and tumor immunity (24/49) over controls and groups of other treatment.
2) When a mixture of tumor cell-incompatible cells was injected into normal mice, tumor growth was inhibited at the site of inoculation in 32 of 40 mice, but induced tumor immunity in only one of these 32 mice. On the other hand, inoculation of this mixture into mice presensitized with the same incompatible cells failed to inhibit tumor growth at the site of inoculation.
3) Chemotherapy with cyclophosphamide or Mitomycin-C and excision of established tumor did not affect tumor immunity in spite of suppressing tumor growth (cyclophosphamide) or prolonging the survival time (cyclophosphamide or surgery).

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Examinations were made to see whether it is possible to use Mitomycin-C in combination with lysosome labilizer or labilizers as a means of enhancing the cytocidal effect of antitumor drugs through promoting the autolysis of tumor cells. Based on experimental findings that both lipoprotein lipase and plasmin labilize the lysosome in tumor cells, clinical studies were made to use Mitomycin-C in combination with dextran sulfate which enhances the activity of lipoprotein lipase in blood and/or urokinase which activates conversion of plasminogen to plasmin. The combination treatment with Mitomycin-C with dextran sulfate and/or urokinase gave an effective rate of 46% in cases with nodular pulmonary metastases, whereas the treatment with Mitomycin-C alone gave an effective rate of 25%, when clinical effect was evaluated in terms of tumor regressing effect. The mean survival period after the detection of pulmonary metastases was 17.3 months in the group given the combination treatment, being longer than 8.0 months in the group treated with Mitomycin-C alone. Enhancement of the tumor regressing effect of Mitomycin-C by combined administration of dextran sulfate and/or urokinase improved the life-prolonging effect of Mitomycin-C therapy, and combination of dextran sulfate and/or urokinase with Mitomycin-C did not increase the side effect of Mitomycin-C in particular.

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Both humoral and cell-mediated immunity were suppressed by four intravenous injections of 100μg each of 4-hydroxyaminoquinoline 1-oxide, employing bacterial α-amylase and picryl chloride as antigens. Preimmunization of mice with diazotized 4-aminoquinoline 1-oxide-conjugated rabbit serum protein by the use of complete Freund's adjuvant prevented immunosuppression by 4-hydroxyaminoquinoline 1-oxide. Anti-hapten titers of these mice were 2⁵ to 2⁸ estimated by passive hemagglutination during the course of the experiments. Passive immunization by transfer of the specific anti-hapten antibody induced prevention from immunosuppression by the reagent. Therefore, it was suggested that the humoral anti-hapten antibody might play an important role in preventing mice from immunosuppression by the reagent by preimmunization with the hapten-carrier conjugate.

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Total energy of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was calculated by means of the molecular orbital method, in which all valence electrons were taken into consideration. On the basis of the total energies obtained, relative stability was compared among various possible structures of MNNG. Electronic charges and bond orders were calculated for MNNG, N-methyl-N'-nitroguanidine (MNG), N-methyl-N-nitrosourea (MNU), and N-butyl-N-nitrosourea (BNU), and they were compared in relation to their chemical and biological activities. Activity and inactivity of MNNG and MNG toward nucleophilic groups such as amines were well explained by the difference in energy increment for the nucleophilic substitution.

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Effect of L-phenylalanine on both anaerobic glycolysis and growth of tumor cells was examined. L-Phenylalanine in 20mM concentration inhibited glycolysis of Ehrlich ascites tumor cells by 50%. Growth of the ascites cells was suppressed by feeding of the host mice with a diet containing 7% L-phenylalanine. This effect seemed highly specific to phenylalanine since no suppressive effect was observed by administration of other ammo acids, including L-alanine, L-glutamic acid, glycine, L-histidine, L-isoleucine, L-leucine, L-lysine, L-methionine, L-proline, L-threonine, L-tryptophan, L-tyrosine, and L-valine. Phenylalanine did not show any suppressive effect on growth of the tumor cells which had been mainitained for 11 generations in mice fed the phenylalanine diet. L-Phenylalanine could not suppress the growth of Walker tumor or the rat ascites hepatoma AH-130 cells.

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In order to find specific chromosomal changes, the trypsin-Giemsa banding method (G-banding) was applied to cells with nine different abnormal karyotypes which appeared spontaneously in more than 20% of the cells in two diploid lines of rat liver cells. By the conventional Giemsa staining method, these nine cells were found to have near-diploid chromosome number of 41 to 43. Seven of them had 41 or 42 chromosomes with one different marker chromosome and the remaining two had 43 chromosomes containing an extra largest subtelocentric chromosome, presumably No. 1 chromosome. The G-banding method revealed that every marker chromosome in the 7 abnormal karyotypes resulted from either fusion or translocation of two different chromosomes, and No. 1 chromosomes were involved in 6 of the 7 marker chromosomes. The extra largest subtelocentric chromosome in two abnormal karyotypes was also identified as No. 1. These results indicate that No. 1 chromosomes were frequently involved in numerical and structural changes in 8 of the 9 abnormal karyotypes, and 8 of these had a complete or partial No. 1 trisomy, especially an extra distal part of its long arm. This part of No. 1 chromosome may have genes related to cell growth in vitro, since these cells with abnormal karyotypes proliferated actively and then overgrew normal diploid cells within a short period.

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The neutralizaation kinetic curve experiment used for estimation of antibodies to herpes simplx virus type 1 (HSV-1) and type 2 (HSV-2) in human sera was standardized. Basic tests using sera of rabbits immunized with HF (HSV-1) and with UW-268 (HSV-2) strain indicated that the K value against HSV-2 minus two-tenths that against HSV-1 could express the level of specific anti-HSV-2 neutralizing antibody, and that the resulting value higher than 0.25 could be regarded as being significantly positive. Based on this criterion, a total of 75 patients with uterine cervical carcinoma and 105 age-matched control women were examined for anti-HSV-2 antibody. In both the cancer and control groups, the positive rate as well as the mean titer of this antibody was found to increase with age, but this increase seemed to start at relatively younger age in the cancer group. Difference between the two groups was small; in th case of individuals younger than 50 years the positive rates in the cancer and control groups were 63-77% and 52-58%, respectively, whereas no difference could be observed in the case of older women. In the cancer group, higher incidence of specific anti-HSV-2 antibody was seen in patients of advanced clinical stages than in the rest.

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Immunohistological technique, using the FITC-labeled antibody against human seromucoid, revealed that seromucoid attached firmly to the plasma membrane region of gastric carcinoma cells but not to surrounding inflammatory cells. This observation served as evidence that seromucoid behaved as 'symbodies' designated by Apffel and Peters.

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The mucopolysaccharide pattern of the spleen in Friend leukemic mice was remarkably different from that of the normal mice. Glucosamine-containing mucopolysaccharides are predominant in the former, while galactosamine-containing mucopolysaccharides are predominant in the latter.

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Some differences in concentration of total and individual amino acids were observed between normal and tumorous tissues of the bladder, but only a slight difference was noted between normal and corresponding tumorous tissues from the kidney and the prostate.

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The effect of Neocarzinostatin on molecular size of mammalian cell DNA was examined using alkaline sucrose density gradient centrifugation. Either single-strand breaks or alkali-labile bonds were suggested to be formed in calf thymus DNA treated with Neocarzinostatin, as well as in cellular DNA of leukemia L-1210 cells incubated with this antibiotic.

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Benzoly and benzenesulfonyl derivatives were active against L-1210 leukemia though acetyl and methylsulfonyl derivatives were not. The former two compounds were more active and less toxic than 1-(2-tetrahydrofuryl) derivative in L-1210 system. By oral treatment, benzoyl derivative was more active than 1-(2-tetrahydrofuryl) derivative.

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A DNA repair inhibitor, 2-chloroethyl isocyanate, which is a metabolic product of 1, 3-bis-(2-chloroethyl)-1-nitrourea (BCNU) and has no antitumor effect, enhanced the cytotoxic effect of nitrogen mustard (HN₂) on a HN₂-resistant line of hepatoma, AH-44. This is a new approach to the chemotherapy on alkylating agent-resistant tumor.

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