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Biomedical subjects

H Onodera

Publications and source records attributed to H Onodera.

At least 325 records · Page 18Linked to original sources
PubMed1983

Spontaneous tumors in F-344/DuCrj rats.

Spontaneous tumors in 296 male and 297 female F-34/DuCrj rats used as control groups in six carcinogenicity tests were tabulated and evaluated. In males the most frequent tumors were testicular interstitial cell tumors, followed by mammary fibromas and fibroadenomas, mononuclear cell leukemias, pheochromocytomas, C-cell adenomas of the thyroid, pituitary adenomas, preputial adenomas, neoplastic nodules of the liver, and lung adenomas. In contrast, in females pituitary adenomas, uterine endometrial stromal polyps, mammary fibroadenomas, mononuclear cell leukemias and C-cell adenomas were the most common. Various other tumors of almost all other organs and/or tissues were found, although their incidences were low. Variability in the rates of incidence in some tumors was observed in different control groups.

Age Factors↗
PubMed1982

Carcinogenicity of N-alkyl-N-(acetoxymethyl)nitrosamines after subcutaneous injections in F-344 rats.

As model compounds for metabolically activated N,N-dialkylnitrosamines, five N-alkyl-N-(acetoxymethyl)nitrosamines were synthesized and their carcinogenicity was tested in F-344 rats of both sexes. Compounds used in this study are N-methyl-(MAMN), N-ethyl-(EAMN), N-propyl-(PAMN), N-butyl-(BAMN), and N-isobutyl-N-(acetoxymethyl)nitrosamines (i-BAMN). All chemicals were dissolved in olive oil and rats received 10 weekly subcutaneous injections of these chemicals (10 X 5 mg MAMN or equimolar amounts of other chemicals) at the interscapular region. Subcutaneous tumors were detected in many rats of all groups treated with the chemicals, although no tumor was detected in the control group. Lung and/or thyroid tumors were also observed in many rats in the experimental groups. The incidence of subcutaneous tumors was highest in EAMN, followed in order by MAMN, PAMN, BAMN, and i-BAMN. On the contrary, the incidence of lung and thyroid tumors was highest in MAMN and decreased as the length of the alkyl chain of the chemicals increased. Histologically, almost all subcutaneous tumors were malignant fibrous histiocytomas. The results indicate that the chemicals possess systemic as well as local carcinogenicity in F-344 rats. The potent carcinogenic effects at the injection site of the alpha-acetoxy nitrosamines, coupled with their direct mutagenic activity reported previously, support the notion that these derivatives are useful as models for the ultimate form in the metabolic activation of N,N-dialkylnitrosamines.

Animals↗
PubMed1982

Carcinogenicity studies of sodium nitrite and sodium nitrate in F-344 rats.

The carcinogenicity of sodium and of sodium nitrate was examined in F-344 rats. Sodium nitrite was administered in the drinking-water for 2 yr at levels of 0.125 or 0.25%. Sodium nitrate was given in the diet at levels 2.5 or 5%. A variety of tumours occurred in all groups including the controls. The only significant difference between treated and control groups in the total number of tumours detected in either of the studies was a significant decrease in tumour incidence in the high-dose females given nitrite compared with controls. There was no positive dose-response relationship either in the incidence or in the induction time of tumours in either of the studies. The only significant result was a reduction in the incidence of mononuclear cell leukaemias in the experimental groups in both studies. It is concluded that sodium nitrite and sodium nitrate did not exert a carcinogenic effect that could be detected under the conditions of this study in which the animals showed a high incidence of spontaneous tumours.

Animals↗
PubMed1982

Left ventricular-right atrial communication with an aneurysm of the atrioventricular membranous septum. A case report.

A 40-year-old man with combination of left ventricular-right atrial communication and aneurysm of the atrioventricular membranous septum is presented. A supravalvular type defect, 14 X 15 mm in size, was closed with a Teflon patch. An oval shaped aneurysm of the atrioventricular membranous septum, 20 X 17 mm in size was also noted, but was left untouched. To our knowledge, this is the first reported case with this combination in Japan.

Adult↗
PubMed1982

Delivery of fungal beta-galactosidase to rat brain by means of liposomes.

A significant increase in beta-galactosidase activity was observed in the brain of rats 1 hr after an intravenous injection of liposomes containing beta-galactosidase purified from Aspergillus oryzae. The increased activity was proved to have features of the fungal enzyme by differentiating it from rat's native beta-galactosidase in both heat stability and immunochemical studies. Blood content of rat brain tissue under the experimental conditions employed was estimated as 0.83% (v/w) from an infusion experiment of 131I-labeled human serum albumin. The net uptake of fungal beta-galactosidase by rat brain was calculated as equal to 10 micrograms protein of the fungal enzyme or 0.31% of the injected dose/g tissue, which gave rise to 4.4-fold net increase in enzyme activity above control levels. The experiments clearly demonstrated that liposome-entrapped fungal enzyme was allowed to penetrate the blood-brain barrier and to gain access to rat brain, suggesting liposomes as an effective carrier for exogenous enzyme delivering to the central nervous system of patient with inherited lysosomal storage diseases.

Animals↗
PubMed1982

Histologic findings of ductus arteriosus and pulmonary vascular disease in interrupted aortic arch.

There are still a number of unsolved problems concerning the total correction of interruption of the aortic arch. Here we report a histopathological investigation of the patent ductus arterious and pulmonary vascular disease using autopsy material of a patient with Celoria type B interruption of the aortic arch who died postoperatively. The so-called ductus arteriosus between the pulmonary arterial trunk and the descending aorta was lacking in elastic fibers and smooth muscle cells at the media showing discontinuous, transverse fibrous tissue. The vessel walls were weak and normal development was apparently impossible. Consequently, it was concluded that in the reconstruction of the aortic arch in such cases with PDDT, it is advisable not to use the patent ductus arteriosus. In this case, hypertrophy of the media of small pulmonary arteries was marked, but pulmonary vascular intimal lesions were mild. With regard to the pathogenesis, it is thought that there was sufficient thickening of the media of the pulmonary arterial system in response to the pulmonary hypertension present from birth, and it prevented the progression of the intimal lesions by accommodating to the intraarterial pressure.

Aorta↗
PubMed1982

Platelet sensitivity to adenosine diphosphate and to prostacyclin in diabetic patients.

We studied the platelet sensitivity to adenosine diphosphate (ADP) and to prostacyclin (PGI2) in order to clarify the mechanism of the onset or development of diabetic retinopathy. The platelet sensitivity to ADP in diabetics with simple and proliferative retinopathy was significantly increased as compared with that in diabetics without retinopathy and in controls. The platelet sensitivity to PGI2 in diabetics with simple and proliferative retinopathy was decreased significantly as compared with the normal value. There was a significant negative correlation between the platelet sensitivity to ADP and that to PGI2 in all diabetics. Since the effect of PGI2 on platelets is to inhibit its aggregation, the decreased sensitivity to PGI2 implies a tendency to accelerate platelet aggregation. The increased platelet aggregation due to the alteration of the platelet sensitivity is considered as an important factor in diabetic microangiopathy.

Adenosine Diphosphate↗
PubMed1982

Long-term follow-up of patients who have undergone valve replacements for acquired valvular disease: a clinical and hemodynamic study.

Thirty-three cases, comprizing 5 of mitral regurgitation (MR), 11 of mitral stenosis (MS), 11 of aortic regurgitation (AR) and 6 of AR and mitral steno-regurgitation (MSR), underwent both preoperative and postoperative heart catheterization in association with a muscle exercise test. Comparisons were made between preoperative and postoperative clinical symptoms, hemodynamics and cardiac functions. The following results were obtained: 1) Improvements in clinical symptoms and hemodynamics at rest were observed in all but two patients. 2) Abnormalities in hemodynamics were obtained after the muscle exercise test, even in cases exhibiting normal hemodynamics at rest. 3) An increase in pulmonary artery mean pressure was noted in MR and MS groups after the muscle exercise test. 4) The cardiac function index values in both the MR and MS groups showed lower levels than those in both the AR and AR + MSR groups. 5) The presence of atrial fibrillation and extent of myocardial fibrosis were related to improvements in postoperative cardiac functions.

Adult↗
PubMed1982

Carcinogenicities of 1-ethyl- and 1-amyl-1-nitrosourethans in female donryu rats: dose-effect relations.

Groups of female Donryu rats were given solutions of 100, 50, and 25 ppm of 1-ethyl-1-nitrosourethan (ENUR), and of 400, 200, and 100 ppm of 1-amyl-1-nitrosourethan (ANUR) continuously in the drinking water. The incidence of tumors was nearly 100% in all groups treated with ENUR or ANUR, but with both chemicals the rats showed dose-dependent mean survival times. In the groups treated with ENUR, tumors were most frequent in the upper digestive tract and duodenum, whereas in groups given ANUR tumors were induced only in the upper digestive tract, with none in the duodenum. Tumors of the forestomach were more frequent than those of the esophagus and oral cavity and/or pharynx in groups treated with ENUR. In contrast, the target organs of ANUR were the oral cavity and/or pharynx, and the esophagus, rather than the forestomach. The carcinogenicities of these two chemicals are discussed in comparison with those of other 1-alkyl-1-nitrosourethans.

Animals↗