To explore epidemiological and etiological implications of bladder cancer mortality in Japan, national mortality statistics for 1947∼74 were analysed. Age-adjusted death rate for bladder cancer was on the upward trend in both sexes prior to early 1960's, after which the rate, however, leveled off in males and even on the downward trend in females. The mortality trend of leveling off or down has been already demonstrated in Western countries in much earlier years than in Japan. Almost identical risks for bladder cancer deaths were noted in males born after 1910 and in females born after 1900. The following facts were also revealed: Apparent decrease in bladder cancer deaths among younger population and increase in much older age groups, delay in mean age at death from bladder cancer for 5.7 years in males and 12.7 years in females for the intervening 28 years, virtually unchanged age-specific death rate in males aged below 65 years and its distinct decline in females similarly aged, no definite geographic gradients of standardized mortality ratio over years, and no apparent clustering of high ratios in the prefectures with many highly industrialized areas and large cities, along the Pacific coast. These relevant findings with recent bladder cancer mortality are rather incompatible with the recent remarkable increases in potentially hazardous agents in the environment in Japan. Since bladder cancer is one of the few malignant neoplasms in which the rôle of environmental and occupational agents has been clearly shown to be important, the present fingings might possibly indicate the relative importance of inherent host factors and unidentified environmental factors in bladder cancer. Such a hypothetical concept was further endorsed by the very consistent proportion, over years and over districts, of bladder cancer death in the deaths from cancer of all urinary organs. Further studies on inherent host factors in bladder cancer were emphasized, possibly in the light of the relationship between carcinogenesis and enzyme system in the human body.

View full abstract

In order to investigate the effect of splenectomy on tumor growth, splenectomy was performed in DDS mice transplanted subcutaneously with Ehrlich ascites tumor cells before and after the transplantation. It was found that, in the first control group receiving sham operation, all the mice died of tumor; in the second group that underwent splenectomy 1 week before the transplantation the tumor regressed in every case; in the third group that received splenectomy 5 days after transplantation when tumor became established, the tumor regression was observed in 85% of the animals, and in the fourth group that underwent splenectomy 10 days after transplantation, all the animals died of tumor earlier than the sham-operated first group. In the follow-up observations of 389 patients with gastric cancer who underwent gastrectomy alone and 89 cases who received gastrectomy combined with splenectomy, the 5-year survival rate of the latter group tended to show a better prognosis in a relatively early stage.
It was concluded that splenectomy might inhibit the growth of tumor in a certain early stage, in both animals and humans, and the possible mechanism of this effect of splenectomy was discussed from the immunological aspects.

View full abstract

Benzo [a] pyrene metabolism in various kinds of mammalian cultured cells was measured by a simplified method. Cells growing in the bottom of glass test tubes were treated with 2μM of ¹⁴C-benzo [a] pyrene for 24hr; unmetabolized benzo [a] pyrene was then extracted with organic solvents in the same test tube, and the amount of water-soluble products recovered in the aqueous phase was measured by a liquid scintillation counter. Among rodent embryo cells, embryo cells of C3H/He mice and Syrian hamsters showed a higher activity in benzo [a] pyrene metabolism than those of DDD, AKR, and C57BL/6 mice. Several cell lines sensitive to density-dependent inhibition, such as Y-AK, DL1, and C3H/10T1/2, actively metabolized benzo [a] pyrene to water-soluble products. The metabolizing activity of C3H/He mouse embryo cells was markedly enhanced by pretreatment with benz [a] anthracene. The amount of water-soluble products by phytohemagglutinin-stimulated human lymphocytes was much Less than that by most cultured cell lines and embryo cells, but clearly increased with extension of culture days.

View full abstract

A series of 200 normal serum samples obtained from healthy blood donors belonging to different religious communities and castes were examined for transferrin phenotypes by vertical polyacrylamide gel electrophoresis. Of these, 196 showed the common CC phenotype, while 4 showed CD phenotype, without any correlation with the caste or community. In another study involving 102 cases of malignancy, no relationship was observed between the transferrin phenotype and the type of malignancy, except in the case of Hodgkin's disease, which showed B₂C phenotype.

View full abstract

The basic protein prepared from AH-130 ascites hepatoma cells was tested for its effect on the cell-mediated immune response of Donryu strain rats. The basic protein suppressed the response of peripheral and lymph node lymphocytes to phytohemagglutinin and lymphocyte trapping in the antigen-draining lymph node. These results indicated that the basic protein from tumor tissue possibly had an immunosuppressive activity and affected inadequately the cell-mediated immune response as usually observed in tumor-bearing hosts.

View full abstract

The M1 line cells of mouse myeloid leukemia can be induced to differentiate in vitro into macrophages by a factor in human amniotic fluid. The macrophages showed phagocytosis and locomotic activity, and also gained Fc receptors on the cell surface. This factor in amniotic fluid capable of inducing differentiation of M1 cells was heat-labile, trypsin-sensitive, and non-dialysable. A growth-stimulating factor for the M1 cells was also found in the human amniotic fluid, and it was heat-stable and trypsin-resistant. The conditioned medium obtained from the amnion had the activity of differentiating the M1 cells.

View full abstract

The activities of lysosomal enzymes, such as lysozyme, acid protease, and β-glucuronidase, were induced with glucocorticoids during differentiation of cultured mouse myeloid leukemia line cells (M1). The induction of lysozyme activity accompanied by phagocytosis in M1 cells was most pronounced in these lysosomal enzymes. Although lysozyme activity could not be detected in undifferentiated cells, it showed a marked increase from the second day of incubation of M1 cells with dexamethasone. On the 5th day of incubation, the activity was about one-half that of mouse peritoneal macrophages.
There was a competitive interaction among different steroids on induction of lysozyme activity in M1 cells. 11β-Hydroxyprogesterone and 11-deoxycortisol could not induce the maximal level of the activity, and cortisone and fluoxymesterone were not active in inducing the enzyme activity. However, these steroids inhibited the induction of enzyme activity with dexamethasone, prednisolone, or hydrocortisone. Induction of lysozyme activity and phagocytic activity of M1 cells with dexamethasone was inhibited by 5-bromodeoxyuridine or puromycin at a concentration that did not interfere with the growth of cells. Differentiation could not be induced in DR-6 cells isolated from M1 cells even in a high concentration of dexamethasone. Neither lysozyme activity nor other lysosomal enzyme activities could be induced in DR-6 cells with dexamethasone.
These results indicate that glucocorticoids are capable of inducing some lysosomal enzyme activities as well as morphological and functional differentiation in M1 cells, and among these enzymes, lysozyme activity is a fairly suitable biochemical marker for the differentiation of M1 cells.

View full abstract

A permanent cell line (S-7512) was established by cell culture from the subcutaneous metastatic tumor of a human rectal cancer and has been maintained for 18 months. Cultured cells grew as isolated and piled-up colonies of epithelial cells, each with a scanty cytoplasm and a large nucleus containing several nucleoli. The average doubling time of this cell line was 57hr and plating efficiency was 30.1∼45.2% in a liquid medium. The modal chromosome number was 115 but a marker chromosome was not evident. Electron microscopic examination revealed many microvilli, free ribosomes, and abundant glycogen granules. Heterotransplantation of the cultured cells produced a large tumor and its microscopic examination showed the same histological appearance as the original tumor (carcinoma simplex). Carcinoembryonic antigen level of the spent medium of the confluent culture was 235.50ng/3.2×10⁶ cells.

View full abstract

N-Butyl-N-(4-hydroxybutyl) nitrosamine (BBN), which selectively induced urinary bladder tumors in several experimental animal species, was found to cause damage of DNA in the bladder epithelium. Wistar strain rats were given 100mg/kg of BBN intravesically and killed after 2, 6, 12, 24, or 48hr. DNA damage was examined by measuring the change in sedimentation pattern in an alkaline sucrose gradient. Amount of DNA in each fraction was determined by fluorescence spectrophotometry. At 2hr, the sedimentation profile shifted from heavier (No. 15, control peak) to lighter (Nos. 2∼4) fractions, and the maximum effect appeared at 6hr as a single peak in the lighter fractions. At 12hr, damaged DNA was in the process of repair as two peaks were present, one light and one heavy. At 48hr, the sedimentation profile showed a single peak identical with that of controls indicating complete repair of DNA.

View full abstract

Tumorigenic effect of a diet containing quinoline on the liver of various animals and the synergistic or antagonistic effect by other chemicals on quinoline hepatocarcinogenesis in rats were examined. It was concluded that 4, 4'-diaminodi-phenylmethane (0.1%) and 3-methylcholanthrene (0.0067%) had a significant inhibitory effect on liver carcinogenesis due to quinoline in rats, but 1-naphthyl isothiocyanate (0.06%) and p-hydroxypropiophenone (1.0%) had no inhibitory effect in the present observations. Transmission electron-microscopic study demonstrated the fine structure of vascular tumors induced by quinoline. On the other hand, it was found that quinoline induced liver tumors in both sexes of mice and rats but not in hamsters or guinea pigs. Male rats were more susceptible than females to the tumorigenic action of quinoline, and mice showed the least susceptibility. Histological changes in the liver of rats or mice induced by quinoline were classified as hemangioendotheliomas or hemangiosarcomas and hepatocellular carcinomas. Several rats treated with quinoline had hemangiosarcomatous metastatic foci in the lung.

View full abstract

Hematological studies were carried out serially in the rats transplanted subcutaneously with Yoshida ascites hepatoma AH-109A. Significant changes were observed in fibrinogen level, fibrinogen degradation products, recalcification time, platelet count, and fragmentation of red blood cells. Formation of thrombi was revealed in the vessels of tumor tissue morphologically from early stage when the tumor grew to a palpable size. Thrombi were formed also in the arterioles of the lungs in the terminal stage. Bleeding tendency was noted in some cases at death. These findings suggested the experimental induction of a type of disseminated intravascular coagulation. The systemic changes of the blood occurring in the terminal stage were preceded by localized intravascular coagulation and fibrinolysis in the tumor in early stage of tumor growth.

View full abstract

A diet containing 0.025% of N, N'-2, 7-fluorenylenebisacetamide (2, 7-FAA) was administered orally to 18 Buffalo rats for 3 months and to 21 rats for 5 months which corresponded to non-neoplastic stage and preneoplastic stage of carcinogenesis of the intestinal mucosa, respectively. The mitotic index, labeling index, and generation time of the epithelia of the intestinal mucosa of these stages were examined by autoradiography.
1) The mitotic index and labeling index decreased in the rats fed 2, 7-FAA for 3 months than those of the non-treated controls.
2) Decrease of both indices was also observed in the rats fed 2, 7-FAA for 5 months, except for the proximal part of the colon.
3) Around 1-hr prolongation of the generation time was observed in the epithelia of rats fed 2, 7-FAA for 3 months compared with the non-treated control rats, and this was mainly due to the prolongation of the duration of the G1 phase.
4) Two- or three-hour prolongation of the generation time was observed in the epithelia of rats fed 2, 7-FAA for 5 months compared with the non-treated control rats, and this was mainly due to the prolongation of the duration of the S phase.

View full abstract

The effect of iodoacetamide or Tween 60 on carcinogenicity of methylnitrosocyanamide (MNC) in rats was examined. A significant increase in the incidence of the forestomach tumors (P<0.01) was observed in rats treated with MNC and iodoacetamide simultaneously. Moreover, there were 2 cases of glandular stomach tumors in rats treated with MNC and Tween 60 simultaneously. They were one well-differentiated adenocarcinoma and one polypoid hyperplasia. This result indicates that MNC under certain conditions is carcinogenic to the glandular stomach of rats in addition to the forestomach. Tween 60 might act by facilitating direct contact between MNC and the glandular stomach mucosa.

View full abstract

A newly synthesized water-soluble nitrosourea derivative, 1-(2-chloroethyl)-3-(β-D-glucopyranosyl)-1-nitrosourea (GANU; NSC-254157) has marked activities against experimental tumors such as lymphoid leukemia L-1210, ascites sarcoma-180, ascites hepatoma AH-130, and Walker carcinosarcoma-256. A single intraperitoneal injection of the compound is more effective than successive injections on the L-1210 system.
An especially interesting point is that both the single intraperitoneal and single oral administrations 2 days after tumor implantation showed a high effectiveness. In addition, growth of the mammary adenocarcinoma transplanted subcutaneously on the back of mice was also considerably suppressed by successive intraperitoneal injections of the compound.

View full abstract

Chronic toxicity of 2-(2-furyl)-3-(5-nitro-2-furyl) acrylamide (AF-2), which had been widely used in Japan as a food additive, was studied in both sexes of ICR/JCL mice by feeding a diet containing AF-2 in a concentration of 0.4% or 0.08%. The experiments confirmed its definite carcinogenicity in the forestomach, with dose dependency; more than 70% of mice fed the higher dose developed tumors, the majority of which were squamous cell carcinomas with metastatic growths, whereas, with a lower dose, fewer tumors occurred, following a longer latent period. In addition, possible leukemogenicity was suggested by a higher incidence in AF-2-fed females (10.8%) over that in control females (3.2%). The development of non-neoplastic lesions in the liver and kidneys, and of amyloidosis in various organs was also observed in some of AF-2-fed mice.

View full abstract

Esophageal carcinomas were induced in three of five rabbits given 0.25% N-methylbenzylamine and 0.16% NaNO₂ in their drinking water. The three rabbits with carcinoma had consumed more than 94g of NaNO₂ and had survived for more than 536 experimental days. The esophageal carcinomas were a slightly elevated type, and no polypoid lesions were seen. They were classified histologically as squamous cell carcinomas or adenosquamous carcinomas, or both. No metastases were found. The other two of the five rabbits died early in the experiment before any esophageal carcinoma had developed.

View full abstract

Kinetics of cell death by hyperthermic treatment at 44° was analyzed using cultured mouse mammary carcinoma cells, and compared with that after X-irradiation. The cells treated with hyperthermia began to die randomly with a mean lethal time of 10hr after a lag time of 10hr. After irradiation, the lag time and mean lethal time were 40 and 34hr, respectively. Early appearance of dead cells by hyperthermic treatment indicates that the critical target is related to cellular metabolism.

View full abstract

Effect of carbon tetrachloride on the carcinogenicity of the flower stalk of Petasites japonicus was examined in 3 experimental groups of inbred strain ACI rats. Group 1 received 4% petasites diet until termination of the experiment and intragastric administration of CCl₄, once every 2 weeks, for a total of 15 times. Group 2 received only 4% petasites diet, and Group 3 CCl₄ and a basal diet. Another group of rats which were fed a basal diet served as a control group. Both Groups 1 and 2 showed the same incidence of hemangioendothelial sarcoma of the liver (6/22). However, the incidence of hyperplastic liver nodules (19/22) and liver cell adenomas (8/22) in Group 1 was significantly higher than in Group 2 (2/22, 0/22). No hyperplastic liver nodules or liver cell adenomas were noted in Group 3. These results indicate that the administration of CCl₄ probably enhanced the carcinogenic activity of Petasites japonicus in hepatocellular tumorigenesis. Three hemangioendothelial sarcomas of the liver induced in rats in Groups 1 and 2 were subcutaneously transplanted and established as transplantable tumor lines.

View full abstract

All nude mice bearing primary or secondary transplants of a human yolk sac tumor exhibited a high serum α-fetoprotein level. This finding clearly indicates the synthesis of α-fetoprotein by the human yolk sac tumor and supports an idea that human yolk sac tumor simulates yolk sac endoderm not only morphologically but also functionally.

View full abstract

Incidence of auditory sebaceous gland tumor induced by 7, 12-dimethylbenz [a] anthracene in female rats increased significantly by neonatal androgenization. Naonatal treatments with 17β-estradiol and progesterone showed no significant changes in the tumor induction.

View full abstract