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Biomedical subjects

M Arai

Publications and source records attributed to M Arai.

At least 667 records · Page 37Linked to original sources
PubMed1982

Induction of preneoplastic and neoplastic lesions in rats treated N-nitroso compounds.

Dose-related changes of incidences of pre-neoplastic and neoplastic lesions in the liver or urinary bladder were examined with N-nitroso-dimethylamine (NDMA) or N-nitrosobutyl-4-hydroxybutylamine (NBHA) respectively. The incidences of lesions by the two carcinogens were compared in short-term and long-term experiments. In a short-term experiment, rats were given a basal diet containing NDMA at concentrations of 10.0, 1.0 and 0.1 mg/kg for 6 weeks, after initiation by a single i.p. injection of N-nitrosodiethylamine (NDEA). Similar, long-term experiments (96 weeks) were also performed, but without NDEA pretreatment. A clear dose-related effect was found in the induction of pre-neoplastic lesions when the groups given 10.0 and 1.0 mg/kg NDMA were compared. This coincided with the results of a long-term experiment on the induction of hyperplastic nodules and hepatocellular carcinomas. Various concentrations of 0.05 to 0.005% of NBHA in the drinking water were given for different periods up to 12 weeks, in a short-term, and up to 40 weeks in a long-term experiment. Incidences of early preneoplastic lesions of the cell surface observed by scanning electron microscopy showed a tendency to increase with longer duration and higher dose (0.01 to 0.05%). A clear dose-dependent effect was found for the incidence of papilloma and carcinoma in the groups subjected to longer treatments.

Animals↗
PubMed1982

[Study on so called "cellular effect" of methotrexate on choriocarcinoma and its mode of manifestation (author's transl)].

The "cellular effect" i.e. temporary elevation of HCG titer may not be infrequently experienced during course of chemotherapy against choriocarcinoma. Present paper is to clarify real view of the effect and mechanism of its manifestation by using a cell-line (GCH-nu). 1) Cellular growth was suppressed moderately by 10(-7), 10(-6) and 10(-5)M MTX. 2) During 2-4 days of administration at these concentrations of MTX HCG per ml medium was elevated 5 times. HCG in cells per mg protein were also higher 5-7 times. 3) HCG-beta in media was enhanced 5-7 times in MTX group. 4) Estrone, estradiol and progesterone were not altered. 5) Choriocarcinoma cells developed marked enlargement of nuclei and cells, multinucleation and cytoplasmic vacuolization. 6) Cytochemistry of heat stable ALP revealed increased activity especially in cells with morphological changes. ALP examined by biochemical method was enhanced 5 times. 7) Amount of protein per cell increased 10 times after giving MTX. Real view of so-called "cellular effect" includes elevations of HCG-beta and ALP activity as well as HCG, whereas sex steroids are not apparently related. The data in addition to morphological and cytochemical changes reveal that MTX may induce differentiation of choriocarcinoma cells into those of syncytial type, which then sustain the "cellular effect".

Animals↗
PubMed1981

Purification of an acidic alpha-D-mannosidase from Aspergillus saitoi and specific cleavage of 1,2-alpha-D-mannosidic linkage in yeast mannan.

An acidic alpha-D-mannosidase (alpha-D-mannoside mannohydrolase, EC 3.2.1.24) has been isolated from culture filtrate of Aspergillus saitoi. The extracellular alpha-mannosidase was homogeneous in polyacrylamide gel electrophoresis. The molecular weight of the enzyme was 51 000 and the isoelectric point pH 4.5. The purified enzyme has a pH optimum of 5.0, a Km of 0.45 mM with baker's yeast mannan and has no activity towards p-nitrophenyl-alpha-D-mannoside. The mode of action of the enzyme has been studied with baker's yeast mannan and saké yeast mannan. The enzyme cleaves specifically the 1,2-alpha-linked side chain, producing free mannose.

Aspergillus↗
PubMed1981

Liposarcoma of the breast, review of the literature and a report of a case.

A case of gigantic liposarcoma of the breast in a 52-year-old woman was reported. She had a small indolent mass in the left breast for twenty years. The mass grew rapidly from the summer of 1979 and became gigantic and penetrated the skin over the mass. Her general condition on admission was poor but resection of the tumor was carried out. She suddenly died of cardiac failure with electrolytes imbalance 13 days after the operation. The diagnoses of liposarcoma, predominantly myxoid, was made on the basis of light and electron microscopic findings. Forty cases of liposarcoma of the breast were collected from the literature. The possibility of malignant transformation of a benign tumor was suggested.

Breast Neoplasms↗
PubMed1981

Cytopathological effect of partial cystectomy of rats.

The effect of partial cystectomy on induction of DNA synthesis in the urinary bladder epithelium was studied in a total of 147 male F344 rats. DNA synthesis started 12 hours after 75% or 50% resection of the bladder, and reached a maximum at 48 hours with a mean labelling index of 15.8% after 75% partial cystectomy and 13.8% after 50% partial cystectomy. In these two groups the proliferative activity of bladder epithelial cells returned to normal after 2 weeks and 1 week, respectively. Cytodifferentiation of epithelial cells, observed by transmission and scanning electron microscopy, remained normal during the regeneration process.

Animals↗
PubMed1981

Candiplanecin, a new antibiotic from Ampullariella regularis subsp. mannitophila subsp. nov. I. Taxonomy of producing organism and fermentation.

A soil isolate of actinomycete, strain No. 43871 produced a new antifungal antibiotic, candiplanecin. Pale brownish to yellow orange color of colonies on agar media, the formation of bottle-shaped, cylindrical sporangia bearing motile spores and the presence of meso-DAP and glycine in the cell wall ascribed this strain to genus Ampullariella. From its morphological characteristics together with the cultural and physiological features, this strain was determined to be a new subspecies of Ampullariella regularis and designated as Ampullariella regularis subsp. mannitophila subsp. nov. (FERM-P No. 5646). Production of candiplanecin was carried out by conventional submerged culture, in which 2 micrograms/ml as the highest antibiotic titer was obtained.

Actinomycetales↗
PubMed1981

Candiplanecin, a new antibiotic from Ampullariella regularis subsp. mannitophila subsp. nov. II. Isolation, physico-chemical characterization and biological activities.

New antibiotic, candiplanecin, was found in the culture broth of an actinomycete identified as Ampullariella regularis subsp. mannitophila subsp. nov. Candiplanecin was produced by conventional submerged culture and isolated by column chromatography on Diaion HP 20 followed by extraction with ethyl acetate and further column chromatography on Sephadex LH-20 column and finally on PrepPAK-500/C18 column. The antimicrobial spectrum of the antibiotic revealed its activity against yeasts and fungi.

Actinomycetales↗
PubMed1981

[The phenol turbidity test for measurement of pulmonary surfactants in amniotic fluid--rapid test for fetal lung maturity (author's transl)].

A simple and sensitive procedure for the quantitative estimation of pulmonary surfactants in the amniotic fluid is described. The method is based on the formation of turbidity from the amniotic fluid surfactants with phenol. Amniotic fluid drawn through an intrauterine catheter was centrifuged at 2000 rpm for 5 min. One ml of 5% aqueous phenol solution was added to 1.0 ml of the diluted supernatant. Control solution was prepared by addition of 1.0 ml of distilled water to the supernatant, instead of phenol solution. The turbidity was measured spectrophotometrically against control at 340 nm 5 to 10 min after agitation on a Vortex mixer for 5 sec. The turbidity obtained from amniotic fluid with phenol was proportional to the increase in total phospholipids in the fluid measured enzymatically. Moreover, only lecithin in the phospholipids was related to the turbidity formation. Sphyngomyelin, lysolecithin, phosphatidylethanolamin did not produce any turbidity with phenol. The spectrophotometric reading of 87 cases (31-41 weeks) was ranged at 0.18-3.52. Four cases with lower value (0.40) showed neonatal respiratory problem. The phenol turbidity test is more useful for the detection of fetal lung maturity comparing with the generally used shake test.

Amniotic Fluid↗
PubMed1981

Scanning electron microscopic examination of reversible hyperplasia of the rat urinary bladder.

Urinary bladder damage caused by surgical incision, freeze-ulceration, or formalin instillation in male Fischer 344 rats was studied by light and scanning electron microscopy. The first two methods resulted in focal ulceration of the urinary bladder; the last induced diffuse mucosal damage. With each method, the damage was followed by regenerative hyperplasia and repair, the bladder mucosa returning to normal in 3-4 weeks. Epithelial cells in the hyperplastic areas had ropy microridges and uniform short microvilli on their luminal surfaces as observed by scanning electron microscopy. When the hyperplasia was marked, with nodular and papillary formation, occasional epithelial cells had pleomorphic microvilli on their surfaces. Rats treated either by surgical incision or freeze-ulceration had normal bladders after a 2-year observation period. Combined with results from previous experiments, pleomorphic microvilli are not a marker of neoplasia or irreversibility but appear with marked or prolonged mucosal proliferation even if reversible.

Animals↗