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H Tsuda

Publications and source records attributed to H Tsuda.

At least 523 records · Page 29Linked to original sources
PubMed1987

Altered enzyme expression in propylnitrosamine-induced Syrian hamster lung lesions.

Focal proliferative and neoplastic lung lesions induced in Syrian hamsters by dihydroxy-di-n-propylnitrosamine (DHPN) were investigated using a combined histochemical, autoradiographic and electron microscopic approach. Expression of elevated glucose-6-phosphate dehydrogenase (G6PD) and gammaglutamyl-transpeptidase (GGT) activities and levels of immunohistochemically demonstrable glutathione S-transferase placental form (GST-P) were evident in epithelial cells of focal proliferative populations and bronchioloalveolar neoplasms. Binding for the GST-C form, normally only weak, became very pronounced in the stromal elements of DHPN-induced lesions. Increased labelling with tritiated thymidine was associated with increase in morphological atypia within the tumours. Although the enzyme phenotype findings were equivocal the presence of lamellar bodies in some cells of focal proliferative and neoplastic lesions suggested an origin from alveolar type II cells. The present results regarding changed enzyme phenotype in lung lesions suggest important similarities at the biochemical level for the process of neoplasia in the different target organs of DHPN in the hamster and indicate that GST-P may be a useful 'marker' for lung neoplasia.

Adenocarcinoma↗
PubMed1987

Effect of tumor promoter TPA on spontaneous and mitomycin C induced mitotic recombination in Drosophila melanogaster.

It has been proposed that mitotic recombination is involved in tumor promotion. To test this idea, we investigated the effect of a tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), on spontaneous and mitomycin C (MMC)-induced mitotic recombination in Drosophila melanogaster. The test system used was the wing-spot assay. Third instar larvae (mwh+/+flr) were treated with MMC (0-0.3 mM) for 6 h and fed media containing TPA (0-10 micrograms/ml), and the wings of surviving adults were analyzed for the presence of mutant spots. The results are: (1) MMC induced twin spots as well as single spots dose dependently (0.03-0.3 mM). (2) TPA itself did not induce twin spots or single spots in the range of doses examined (0.1-10 micrograms/ml). (3) TPA did not enhance the frequencies of twin or single spots induced by MMC. These results indicate that TPA induced neither mitotic recombination nor mutations under these experimental conditions. Thus the results would not support the mitotic recombination theory in tumor promotion. Rather, in this study, TPA posttreatment resulted in reduced frequencies of mutant single spots induced by MMC.

Animals↗
PubMed1987

Differential regulation of colony-stimulating factors and interleukin 2 production by cyclosporin A.

Stimulation of T lymphocytes with mitogens or antigens is followed by proliferation and lymphokine production. Although cyclosporin A (CsA), an immunosuppressive drug, has been shown to inhibit the production of certain lymphokines, including interleukin 2 (IL-2), interleukin 3 (IL-3), and gamma-interferon, its effect on the production of granulocyte/macrophage colony-stimulating factor (GM-CSF) has not been evaluated. In the current study, concanavalin A (Con A)-stimulated murine spleen cells secreted GM-CSF, IL-3, and IL-2, and in the presence of CsA (0.1-1.0 micrograms/ml), IL-2 and IL-3 activities were inhibited. In contrast, significant activity was detected when the CsA-treated culture supernatants were assayed on a cell line that is dependent on GM-CSF and/or IL-3. Similar CsA-resistant activity was observed when the EL-4 thymoma cells were stimulated with a phorbol ester [phorbol 12-myristate 13-acetate (PMA)] in the presence of CsA. The activity resistant to CsA was identified as GM-CSF by the ability of specific antibodies against murine recombinant GM-CSF to neutralize its activity. These findings indicate that GM-CSF, in contrast to IL-2 and IL-3, was not inhibited by CsA. In additional experiments, transfer blot of poly(A)+ RNA isolated from PMA-induced EL-4 cells in the presence or the absence of CsA was hybridized with GM-CSF and IL-2 cDNA probes. Expression of the GM-CSF gene in EL-4 cells was detected independent of CsA, whereas CsA inhibited the expression of the IL-2 gene. The present data show that production of IL-2 and IL-3, but not that of GM-CSF, is inhibited by CsA and suggest a differential control mechanism for lymphokine synthesis in T lymphocytes.

Animals↗
PubMed1987

Organ specific modifying potential of ethinyl estradiol on carcinogenesis initiated with different carcinogens.

Estrogen has been shown to exert a modifying potential on carcinogenesis in various organs, and in particular the hormone-dependent tissues. The present experiments were carried out to determine the effects of post-initiation phase administration of ethinyl estradiol (EE) on tumor development in the liver, kidney, lung, thyroid, bladder and esophagus of male F344 rats. Animals were initiated by 2 weeks treatment with 0.05% N-bis(2-hydroxypropyl)nitrosamine (DHPN), 0.1% N-ethyl-N-hydroxyethylnitrosamine (EHEN), 0.03% N-nitrosopiperidine (NPD), 0.02% 2-acetylaminofluorene (2-AAF) or 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in their diet or drinking water, and starting 1 week after initiation, they were given diet with or without a 0.001% EE supplement for 49 weeks, at which point the experiment was terminated. EE significantly increased the development of tumors of the liver (DHPN-, EHEN-, 2-AAF- and NPD-treated groups) and kidneys (EHEN-treated group) but inhibited their development in the lungs (DHPN-treated group) and urinary bladder (BBN-treated group). In the liver, EE also increased the development of glutathione S-transferase P type-positive lesions to various extents depending on the initiator used. EE administration was associated with a decreased incidence of esophageal hyperplasia in the EHEN-initiated group but an opposite increase in the NPD-initiated animals. No effect of EE was evident regarding thyroid lesions.

2-Acetylaminofluorene↗
PubMed1987

Effects of simultaneous treatment with various chemicals on BHA-induced development of rat forestomach hyperplasia--complete inhibition by diethylmaleate in a 5-week feeding study.

Male F344 rats were administered phenobarbital, polychlorinated biphenyl (PCB), retinol acetate, indomethacin, 6-amino-caproic acid, dexamethasone (DEX) or diethylmaleate (DEM) for one week and then were treated with these chemicals plus butylated hydroxyanisole (BHA) for a further four weeks. Histopathologically, the incidence of BHA-induced forestomach hyperplasia was significantly lower in rats treated with PCB, DEX or DEM than in those treated with BHA alone. However, the inhibition by PCB and DEX was only partial and might have been due to decreased food intake. On the other hand, DEM completely inhibited the hyperplastic response to BHA at a dose of 0.25%, and even at lower doses it demonstrated significant inhibition without any decrease in body weight or food intake. The result that DEM, a tissue glutathione depleting agent, can inhibit BHA-associated forestomach hyperplasia strongly suggests that tissue glutathione may be intimately involved in the induction of forestomach hyperplasia by the antioxidant in rats.

Aminocaproic Acid↗
PubMed1987

Enhancement of BHA-induced proliferative rat forestomach lesion development by simultaneous treatment with other antioxidants.

Synergistic effects of butylated hydroxyanisole (BHA) and other antioxidants on induction of rat forestomach lesions were investigated. Groups of F344 male rats were treated with 1% BHA plus 0.7% butylated hydroxytoluene (BHT), 1% BHA plus 1% propyl gallate (PG), 1% BHA plus 1% sodium L-ascorbate (SA), 1% BHA plus 1% DL-alpha-tocopherol (alpha-TP), 0.4% BHT plus 0.4% BHA plus 0.4% PG plus 0.4% SA plus 0.4% alpha-TP, 1% BHA or 2% BHA. Further groups of 10 rats each received antioxidants without BHA as controls. Histological examination revealed significantly increased incidences of hyperplasia in the groups given BHA together with SA or PG at the prefundic region or at the mid region respectively. The forestomach changes induced by BHA together with SA were equal to those induced by 2% BHA. On the other hand, simultaneous treatment with BHA and PG or alpha-TP reduced the incidence of hyperplasia at the prefundic region. It is concluded that mixed treatment with BHA and other antioxidants exerted enhancing or inhibitory effects on the induction of hyperplasia at different sites of the forestomach epithelium.

Animals↗
PubMed1987

Immunohistochemically demonstrated altered expression of cytochrome P-450 molecular forms and epoxide hydrolase in N-ethyl-N-hydroxyethylnitrosamine-induced rat kidney and liver lesions.

A comparison of N-ethyl-N-hydroxyethylnistrosamine (EHEN)-induced preneoplastic and neoplastic lesions in the rat liver and kidney was made with respect to the expression of different drug metabolizing enzymes. Four cytochrome P-450 species (cyt. P-450 UT50, PB3a, MC1 and MC2) and microsomal epoxide hydrolase (mEHb) were investigated along with two glutathione S-transferase species (GST-P and A forms) earlier shown to be elevated in putative preneoplastic lesions in the liver and kidney, respectively. In contrast to the liver lesions, which showed clear decrease in all forms of cyt. P-450s and increase of mEHb, elevated levels of cyt. P-450 PB3a and, to a lesser extent, the other P-450 forms and early elevation to late decrease in mEHb characterized the renal tubular lesions. Thus opposite shift in enzyme phenotype was observed in carcinogen-induced focal lesions of the two organs. Variation in binding levels in the different nephron segments and zones of the liver acinus indicated physiological specialization with regard to the enzymes investigated and suggested that the altered phenotype of preneoplastic populations might be of adaptive significance.

Animals↗
PubMed1987

Inhibition of neoplastic development in rat liver, kidney, oesophagus and forestomach by 4,4'-diaminodiphenylmethane administration.

The modifying effects of 4,4'-diaminodiphenylmethane (DDPM) (0.1% in diet) administration on liver carcinogenesis induced by 2-acetylaminofluorene (2-AAF) (0.02% in diet), 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) ( 0.06% in diet), diethylnitrosamine (DEN) (0.001% in drinking water) and N-ethyl-N-hydroxyethylnitrosamine (EHEN) (0.1% in drinking water), EHEN-induced oesophagus and kidney carcinogenesis and forestomach carcinogenesis induced by butylated hydroxyanisole (1.0% in diet) were examined in F344 male rats. Mean survival time tended to be longer in DDPM-supplemented groups, the difference being significant in DEN + DDPM and EHEN + DDPM groups. Intake of carcinogens was slightly but not significantly reduced by DDPM. The incidences of hyperplastic nodules and hepatocellular carcinomas were significantly decreased in 2-AAF or 3'-Me-DAB + DDPM groups. Pulmonary metastases were also less common in 3'-Me-DAB or EHEN + DDPM groups. Development of papillomas in the oesophagus but not in tumours in the forestomach was also inhibited by DDPM. Inhibition in the different organs was not significantly related to decrease in body weight or carcinogen intake, indicating a mechanism independent of non-specific toxic effects or reduction in food consumption. Some other factors possibly related to its ability to cause bile duct proliferation and/or altered activity of enzymes relevant to drug metabolism may be involved.

2-Acetylaminofluorene↗
PubMed1987

Reciprocal modifying effects of isomeric forms of aminophenol on induction of neoplastic lesions in rat liver and kidney initiated by N-ethyl-N-hydroxyethylnitrosamine.

The effects of four isomeric forms of aminophenols, ortho-, meta-, para-aminophenol and acetaminophen (o-, m-, p-AP and AAP, respectively) on liver and kidney carcinogenesis initiated by N-ethyl-N-hydroxyethylnitrosamine (EHEN) were tested. Rats were given 0.1% EHEN (in their drinking water for 2 weeks) and then diet containing these compounds at concentrations of 0.8% for 49 weeks. Administration of o-AP and AAP significantly decreased the number and area of preneoplastic foci staining immunohistochemically for glutathione S-transferase placental type (GST-P) per unit area of liver section as compared with the values for rats given EHEN alone. o-AP and AAP also significantly decreased the incidence of hepatocellular carcinoma. In contrast, p-AP and AAP significantly increased quantitative values for kidney preneoplastic lesions and renal cell adenoma. It is suggested that the cytotoxic effects of these chemicals preferentially suppressed the proliferation of preneoplastic liver cells, but stimulated the mitotic activity of preneoplastic tubular lesions in the kidney.

Acetaminophen↗
PubMed1987

Placental glutathione S-transferase (GST-P) as a new marker for hepatocarcinogenesis: in vivo short-term screening for hepatocarcinogens.

Our laboratory has developed an in vivo short-term screening test for hepatocarcinogens based on quantitation of gamma-glutamyl transpeptidase (gamma-GT) positive foci. However, gamma-GT positive hepatocytes appear in periportal areas under a variety of circumstances apparently unrelated to hepatocarcinogenesis. Glutathione S-transferase placental type (GST-P), which is hardly detectable in normal rat liver, was recently demonstrated as a new marker protein for preneoplastic liver foci. In experiment I, rats were initially given a single dose (200 mg/kg) of diethylnitrosamine intraperitoneally and 2 weeks later were treated with test compounds for 6 weeks. All rats were subjected to partial hepatectomy at week 3. The long-term development of preneoplastic lesions was followed in rats for 50 weeks. The immunohistochemical investigation of GST-P binding and the histochemical demonstration of gamma-GT in serial sections revealed that almost all gamma-GT foci were GST-P positive, but 5-10% of GST-P foci could not be detected by gamma-GT staining. From week 8, many gamma-GT foci partially lost gamma-GT activity. However, no comparable disappearance of GST-P was evident in the lesions. All hepatocellular carcinomas (HC) found at week 50 consisted of GST-P positive HC cells. In contrast, 37.9% (11/29) of HC were negative for gamma-GT. In experiment II (in vivo short-term screening test for hepatocarcinogens), rats were treated in the same manner as for experiment I and killed at week 8. Fifty-eight chemicals were investigated for their potential to modify GST-P positive foci development.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Enhanced c-fos expression in differentiated monomyelocytic cells is associated with differentiation and not with the position of the differentiated cells in the cell cycle.

Enhanced expression of the proto-oncogene c-fos is reported to be involved in the differentiation of monomyelocytic cells into mature macrophages. Such differentiated cells usually accumulate in the G1 phase of the cell cycle. M1 murine myeloid leukemia cells, which can be synchronized in early and late G1 and can also differentiate into mature macrophages when stimulated with granulocyte colony-stimulating factor (G-CSF), were used to investigate whether the enhanced expression of c-fos in differentiated monomyelocytic cells is associated with the position of the cells in the cell cycle or with their state of differentiation. Our data show that the enhanced expression of the c-fos gene occurs only in fully differentiated cells and not in proliferating or G1-arrested cells. These data imply that the enhanced expression of c-fos in M1 cells is restricted to functionally differentiated cells and not related to the position of the differentiated cells in the cell cycle.

Animals↗
PubMed1987

Induction of tumors in the liver, urinary bladder, esophagus and forestomach by short-term treatment with different doses of N,N'-dibutylnitrosamine in rats.

The multipotential carcinogen N,N'-dibutylnitrosamine (DBN) was given to F344 male rats for 2 weeks at three dose levels to study the concentration dependence of its organ specificity. Groups of 20 rats were given water containing 0.25, 0.125 or 0.063% DBN for 2 weeks and then tap water only to drink until they were killed 52 weeks after the start of the experiment. DBN induced preneoplastic lesions in the liver, esophagus, forestomach and urinary bladder. Carcinoma was found only in the liver. Induction of preneoplastic focal hepatocyte lesions positive for the P-form of glutathione S-transferase (GST-P) was quantitatively dependent on the dose of DBN. In the urinary bladder, the incidences of papillary or nodular hyperplasia (PNH) and papilloma of transitional cells tended to increase at higher doses. The incidence and number per unit length of basal cell-type hyperplasias of the esophageal epithelium were significantly higher in all DBN groups than in the control group, through the increase did not show a clear dose-dependency. The incidence of epithelial basal cell hyperplasia of the forestomach was significantly increased at all doses and the increase was apparently dose-related. These results indicate that even in a short-term experiment, DBN exerted multipotential carcinogenic effects. Thus, this system could be used for assay of the modifying effects of compounds administered subsequently on carcinogenesis in different organs.

Animals↗
PubMed1987

Induction of forestomach lesions in rats by oral administrations of naturally occurring antioxidants for 4 weeks.

The effects of naturally occurring antioxidants on rat forestomach epithelium were compared with those of synthetic antioxidants, butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT), of which the former is a known forestomach carcinogen. Groups of five F344 male rats were given diet containing BHA, BHT, gallic acid, syringic acid, sesamol, caffeic acid, chlorogenic acid, ferulic acid, eugenol or esculin for 4 weeks at a level of 0.7% for BHT or 2% for other compounds. Histological examination of the forestomach showed that BHA induced hyperplasia mainly in the prefundic region near the esophageal orifice, caffeic acid induced pronounced hyperplasia throughout the forestomach epithelium, and sesamol induced large ulcers and hyperplasia in the central region. Thus, these naturally occurring antioxidants showed different toxicities and abilities to induce hyperplasia in the rat forestomach.

Animals↗
PubMed1987

Catechol strongly enhances rat stomach carcinogenesis: a possible new environmental stomach carcinogen.

Catechol (CAS: 120-80-9) is present in the environment, being a major industrial chemical as well as a major phenolic component of cigarette smoke. Continuous oral treatment of rats with 0.8% catechol for 51 weeks after a single intragastric dose of 150 mg/kg of N-methyl-N'-nitro-N-nitrosoguanidine strongly enhanced both forestomach and glandular stomach carcinogenesis. In addition, and more importantly, catechol alone induced adenocarcinoma and adenomatous hyperplasia in the pyloric region of the glandular stomach. These results clearly indicate that this environmental contaminant merits classification as an enhancer of forestomach and glandular stomach carcinogenesis with complete carcinogenic potential for the glandular stomach. Its significance for gastric tumor development in man requires elucidation.

Adenocarcinoma↗
PubMed1987

Differential modification of development of preneoplastic lesions in the Syrian golden hamster initiated with a single dose of 2,2'-dioxo-N-nitrosodipropylamine: influence of subsequent butylated hydroxyanisole, alpha-tocopherol, or carbazole.

The effects of butylated hydroxyanisole [(BHA) CAS: 25013-16-5], alpha-tocopherol [(TC) CAS: 59-02-9], and carbazole [(CA) CAS: 86-74-8] administered subsequent to a single dose of 2,2'-dioxo-N-nitrosodipropylamine [(DOPN) CAS: 60599-38-4] on the development of putative preneoplastic lesions were investigated in Syrian golden hamsters. Whereas the 2 antioxidants BHA and TC inhibited the incidence of both liver and pancreatic lesions, CA, itself giving rise to considerable numbers of enzyme-altered foci, enhanced carcinogenesis in the liver while inhibiting carcinogenesis in the pancreas. All 3 of these agents induced hyperplastic and papillomatous lesions in the forestomachs of treated animals, independent of prior DOPN treatment; these forestomach lesions were not evident in controls. Cellular atypia and invasive growth characteristics signifying malignant change were also observed in BHA-induced forestomach lesions. The results demonstrate that hepatocarcinogenesis in the Syrian golden hamster, like that in the rat, can be inhibited by antioxidants. The similar decrease in putative preneoplastic lesion yield evident in the pancreas of BHA- or TC-treated hamsters, considered in the light of similarities in altered enzyme phenotype in carcinogen-induced lesions of both organs, suggests that common biochemical changes can be an underlying factor in the modification of neoplastic development in liver and pancreas. The present results also provide further evidence that CA has carcinogenic potential for the liver and forestomach of experimental animals.

Animals↗
PubMed1987

Differences in clinical and immunological findings of systemic lupus erythematosus related to age.

Five hundred and seventy patients with systemic lupus erythematosus were classified into 3 groups (younger onset, adult onset and older onset) according to their ages at the time of diagnosis. There were more patients with HLA-Bw35 and/or DR2 in the younger onset group than the adult onset group. Typically related systemic features and serological abnormalities were more frequently found in the younger onset group than the other groups. The disease patterns of the adult onset group were more heterogeneous than those of the other 2 groups. The causes of death in the older onset group were mainly complications such as infections and perforated peptic ulcers.

Adolescent↗