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Biomedical subjects

N Hirota

Publications and source records attributed to N Hirota.

At least 127 records · Page 7Linked to original sources
PubMed1980

Induction of cancer of the glandular stomach in rats by an extract of nitrite-treated fish.

Treatment of a homogenate of the mackerel fish Sanma hirakl with nitrite at pH 3 led to the development of direct-acting mutagenic activity for Salmonella typhlmurium TA-1535. Repeated gastric intubation three times/week for 6 months of an extract containing this mutagenic activity into noninbred Wistar rats led to the induction of tumors in 8 of 12 rats 12-18 months later. Adenomas and adenocarcinomas were found in the glandular stomach, squamous cell carcinoma was observed in the forestomach, and adenocarcinoma was found in the small intestine and pancreas. Furthermore, precancerous lesions (including intestinal metaplasia and glandular hyperplasia of the glandular stomach as well as squamous cell hyperplasia) were noted in virtually all of the animals at risk. No tumors were seen in 8 control rats given the untreated fish extract alone; 1 rat had glandular hyperplasia and intestinal metaplasia. Thus a mutagenic extract of nitrite-treated fish was demonstrated to induce, in the rat glandular stomach, cancers identical to gastric cancer observed in man. Preventive m:asures, including reduction of the intake of pickled foods and the year-round daily availability of foods containing vitamin C, are discussed.

Adenocarcinoma↗
PubMed1979

Intranuclear rodlets in undifferentiated carcinomas of salivary glands in strain A mice in a study involving a tobacco specific nitrosamine, N-nitrosonornicotine.

Undifferentiated carcinomas of the salivary glands were found in 2 of 44 (4.5%) strain A mice injected intraperitoneally with a tobacco specific nitrosamine, N-nitrosonornicotine (NNN). The presence of intranuclear rodlets (INR) in the salivary carcinomas provided the first demonstration of such structures in a non-neuronal tumor in mice. Two types of rodlets were exhibited; one was composed of fibrillar filaments arranged in bundles, and the other was much thicker, branching in form. These INR appeared to be closely associated with nuclear chromatin or nucleoli.

Animals↗
PubMed1979

The sensitivity and heterogeneity of histochemical markers for altered foci involved in liver carcinogenesis.

Subcutaneous injection of iron dextran resulted in a hepatic siderosis within 2 weeks in rats, as previously reported for mice. Hepatic carcinomas as well as neoplastic nodules in rats were entirely or mainly free of stainable iron and, thus, could be readily identified histologically. In addition, early carcinogen-induced altered foci were resistant to iron accumulation. In rats fed 0.02% N-2-fluorenylacetamide (FAA) for 13 weeks, the number of iron-resistant foci identified following iron injection was the same as that observed with dietary iron overload. Histochemical investigation of enzymatic markers that have been used to identify foci in rats revealed that foci characterized by enzymatic reactions of positive gamma-glutamyl transpeptidase and decreased adenosine triphosphatase and glucose-6-phosphatase corresponded to those characterized by resistance to iron accumulation. However, in quantitative analysis of the early carcinogen-induced foci in rats given iron dextran following a diet containing 0.02% 2-FAA for 13 weeks, more lesions were detected by resistance to iron accumulation than by any of these other properties. There was considerable phenotypic heterogeneity among foci for the enzyme markers. It is concluded that resistance to iron accumulation is a more sensitive and reliable marker for early carcinogen-induced altered hepatocellular foci than is any other histochemical property.

2-Acetylaminofluorene↗
PubMed1979

Nonspecific adjuvant immunotherapy of lung cancer with cell wall skeleton of Mycobacterium bovis Bacillus Calmette-Guérin.

Nonspecific adjuvant immunotherapy with Bacillus Calmette-Guérin cell wall skeleton (BCG-CWS) was given to 155 lung cancer patients. Clinical effects of the BCG-CWS treatment were estimated by comparing the survival of the BCG-CWS group with that of a historical control group on the basis of 4-year results. Significant prolongation of survival time has been observed in Clinical Stages II, III (M0) and III (M1). However, most Stage III patients who were given the BCG-CWS treatment died of cancer itself after marked prolongation of survival time. An increase in complete cure rate has been expected only in Stages I and II. Surgicopathological staging was used in resected cases. Resected cases at any stage were sensitive to treatment with BCG-CWS. Histologically, all types of lung cancer including squamous cell carcinoma, adenocarcinoma, and anaplastic carcinoma were sensitive to treatment with BCG-CWS. Intrapleural administration of BCG-CWS to patients with malignant pleurisy was effective in controlling the pleural effusion and prolonging the survival time. No serious complication has been experienced in our study.

Adenocarcinoma↗
PubMed1979

Cytostatic activity of peripheral blood monocytes against bronchogenic carcinoma cells in patients with lung cancer.

Cytostatic acitivity of peripheral blood monocytes against cultured cell lines of bronchogenic carcinoma was examined in patients with lung cancer. Cytostatic activity in lung cancer patients with neither augmented nor suppressed as compared with that of controls such as normal healthy persons, patients with malignancies other than lung cancer, and patients with benign respiratory diseases. There was no correlation between the cytostatic activity of monocytes and the advance of clinical stages of the disease. Conventional modalities of anticancer treatments such as surgery, radiotherapy, chemotherapy, and their combination therapy had no effect on cytostatic activity of peripheral blood monocytes. However, adequate immunotherapy with nocardia rubra cell-wall skeleton augmented the cytostatic activity of peripheral blood monocytes, although adequate immunotherapy with Mycobacterium bovis BCG cell-wall skeleton had no effect.

Adenocarcinoma↗
PubMed1979

Persistence and growth of rat liver neoplastic nodules following cessation of carcinogen exposure.

Altered (hyperplastic) foci and neoplastic (hyperplastic) nodules identified by their resistance to iron accumulation were induced in the livers of F344 rats by limited feeding of N-2-fluorenylacetamide for three, four, or five cycles of 4-week intervals separated by 1 week of a basal diet. Foci were present by the end of three feeding cycles and increased in number with further carcinogen exposure. No nodules were present at the end of three or four cycles, but they appeared at later intervals after removal of the carcinogen. Nodules were present at the end of five cycles of feeding and increased in number later. Thus nodules were found to be persistent and to have the progressive growth ability in situ that is characteristic of neoplasms.

2-Acetylaminofluorene↗
PubMed1979

The resistance of spontaneous mouse hepatocellular neoplasms to iron accumulation during rapid iron loading by parenteral administration and their transplantability.

Spontaneous mouse liver nodules were found to be resistant to iron accumulation induced either by dietary overload or by a rapid protocol of subcutaneous injection of iron dextran. Transplants of 11 liver nodules into the mammary fat pad gave rise to neoplastic growth. Transplants of the less differentiated nodules grew more frequently and rapidly than better differentiated nodules and produced pulmonary metastases. Therefore, these mouse liver nodules are considered to be neoplasms, and their resistance to iron accumulation suggests that this marker will be useful in studying their histogenesis.

Animals↗
PubMed1978

Comparative tumor initiating activity of 10-methylbenzo-[a]pyrene, 7,10-dimethylbenzo[a]pyrene and benzo[a]pyrene.

The tumor initiating activity on mouse skin of benzo[a]pyrene (BaP), 7,10-dimethylBaP, and 10-methylBaP was determined. Each compound was tested at initiating doses of 50 microgram and 100 microgram with promotion by application 3 times weekly of 2.5 microgram tetradecanoylphorbol acetate. BaP induced tumors in 40% (100 microgram) and 25% (50 microgram) of the animals. No tumors were observed in either group treated with 7,10-dimethylBaP. In the groups treated with 10-methyl-Bap, the incidence of tumor bearing animals was 20% at both doses. These results and the results of previous studies on other methylated BaP derivatives suggest that the mechanism of activation of these compounds is similar to that observed for the parent hydrocarbon and probably involves formation of an angular ring diol-epoxide or epoxide.

Animals↗
PubMed1978

Tobacco-specific nitrosamines: formation from nicotine in vitro and during tobacco curing and carcinogenicity in strain A mice.

The formation of tobacco-specific nitrosamines from the major tobacco alkaloid nicotine was examined. Detached leaf tobacco was fed either [2'-14C]nicotine or [2'-14C]nornicotine and air cured. The cured leaf was then analyzed for [2'-14C]N'-nitrosonornicotine ([2'-14C]NNN). The yield of [2'-14C]NNN was 0.007% from nornicotine and 0.009% from nicotine. Because the ratio of nicotine to nornicotine in conventional nicotine-type tobacco is 20-100:1, nicotine is considered to be the major precursor for the carcinogen NNN in tobacco. The formation of other nitrosamines from nicotine in vitro was then studied. Reaction of nicotine with NaNO2 gave rise to NNN, as well as to two other nitrosamines, 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and 4-(N-methyl-N-nitrosamino)-4-(3-pyridyl)butanal (NNA). Analysis of market products revealed the presence of NNK (0.6-24 microgram/g) in chewing tobacco and snuff. The tumorigenic activity of NNN, NNK, and NNA in strain A mice was studied. NNK induced more lung adenomas per mouse than did NNN, whereas NNA was less active than NNN. In addition, two cases of undifferentiated carcinoma of the salivary glands occurred in the NNN experimental groups.

Adenoma↗
PubMed1975

Induction of ovarian tumor in rats with N-butylnitrosourea.

Considerable number (8.2 approximately 10.7%) of ovarian tumors were produced in Sprague-Dawley adult rats treated with multiple oral or intramuscular administration of heavy doses of N-butylnitrosourea. Histologically the tumor was a clear-cell adenma which reminded of embryonal testicular tissue. Electron micrograph revealed secretory function of the tumor cells. It was not possible to find histogenesis in the normal ovarian components.

Adenoma↗