PubMed Health⌕ Search

Biomedical subjects

O Kawamura

Publications and source records attributed to O Kawamura.

17 recordsLinked to original sources
PubMed1992

Genotoxicity of fungi evaluated by SOS microplate assay.

By an introduction of sodium dodecylsulfate for cell lysis and immunomicroplate for mass assay, the modified SOS microplate assay method was established and applied for the evaluation of genotoxicity of mycotoxins and fungal cultures. Among 20 mycotoxins, the carcinogenic dihydrobisfuranoids such as aflatoxin B1, sterigmatocystin, and versicolorin A were positive in the presence of the activation system. While, the carcinogenic anthraquinones and lactones such as luteoskyrin, rugulosin, ochratoxin A, patulin, and citrinin were negative. The survey on genotoxic fungi revealed that, among 15 fungal isolates Aspergillus versicolor, Emericella acristata, and others were positive. Additional survey on 265 fungal isolates have revealed that various Aspergillus genera such as A. flavus, A. parasiticus, A. ustus, A. nidulans, and others were positive for SOS induction, along with several isolates of Fusarium moniliforme. The chemical analysis revealed that the dihydrobisfuranoids such as aflatoxin B1, and sterigmatocystin were the major genotoxic metabolites of several Aspergillus species. The SOS microplate assay system is a simple and rapid procedure for the mass screening of genotoxic fungi, particularly of the dihydrobisfuranoids-producing strains.

Animals↗
PubMed1991

[Interdigestive migrating complex (IMC) and effect of cisapride in patients with non-ulcer dyspepsia (NUD)].

The 24-hr gastric and duodenal pressure measurement was performed in 5 patients with non-ulcer dyspepsia (NUD). The reduction of incidence of IMC and prolongation of the first appearance of IMC after evening meal were observed in NUD patients. The gastroprokinetic agent, cisapride 5 mg, 3 times a day for 7 days significantly increased the incidence of IMC and shortened the time before the first appearance of IMC after evening meal. This result indicates that in NUD patients impaired gastrointestinal motility is present in fasting phases and cisapride may be useful for correcting motility disorders.

Aged↗
PubMed1991

Use of monoclonal antibodies, enzyme-linked immunosorbent assay and immunoaffinity column chromatography to determine ochratoxin A in porcine sera, coffee products and toxin-producing fungi.

Ochratoxin A, produced by a number of fungal species, has been found in many milieu, including porcine sera and coffee beans. It was therefore analysed by enzyme-linked immunosorbent assay (ELISA) in porcine sera, coffee products and fungal cultures, using monoclonal antibodies, a monoclonal antibody-linked immunoaffinity column (IAC) and high-performance liquid chromatography (HPLC). The chloroform extracts of acidified porcine sera were assayed directly by ELISA, with alkaline phosphatase and horseradish peroxidase as marker enzymes, at detection limits of 0.1 and 0.01 ng/ml, respectively. The presence of ochratoxin A in ELISA was confirmed by HPLC. The average contents in the five different lots tested were: 0.4 ng/ml in lot A (19 samples), 0.36 ng/ml in lot B (104 samples), 5.20 ng/ml in lot C (17 samples), 1.24 ng/ml in lot D (23 samples) and 0.22 ng/ml in lot E (24 samples). ELISA of methanol extracts of rice cultures showed the presence of more than 0.1 ng/g in 3 of 15 isolates of Aspergillus, in 16 of 67 isolates of Penicillum and in 7 of 17 isolates of Eupenicillum; none was found in an isolate of Emericella. IAC-HPLC analysis revealed that P. foetidus, which is similar to A. niger and is used for the production of a Japanese alcoholic drink (shou-chuu), also produced ochratoxin A. Use of IAC-HPLC to analyse coffee beans and instant coffee power resulted in the sharp resolution of ochratoxin A without complicated clean-up steps. The IAP-HPLC technique could thus be used for mass surveys of ochratoxin A residues in biological specimens.

Animals↗
PubMed1990

The relationship between interdigestive gallbladder and gastroduodenal motility in man.

The relationship between interdigestive gallbladder and gastroduodenal motility simultaneously with the behavior of plasma motilin and CCK levels in 20 subjects was investigated. We used an infusion catheter method for the measurement of gastroduodenal motility, and real-time ultrasonography for the measurement of gallbladder size. In gastric phase II, the gallbladder contracted with extension of the major axis and shrinking of the minor axis, with its minimum volume being 84% of the volume in phase I. The gallbladder then filled rapidly assuming a sphere-like shape with extension of the minor axis and shrinking of the major axis in gastric phase I. This motility was recognized only during the gastrointestinal interdigestive migrating complex (GI-IMC) cycle, originating in the stomach, and was associated with an increase of motilin levels, it was not seen before or after the intestinal IMC (I-IMC), which originated in the duodenum without contraction of the stomach or an increase of motilin levels. Furthermore no apparent relationship was recognized between CCK and gastric or gallbladder motility. Our findings suggest that gallbladder motility in the interdigestive period has a close relationship with gastroduodenal motility and is related to the appearance of the GI-IMC.

Adult↗
PubMed1990

Antitumor activity of T-2 toxin-conjugated monoclonal antibody to murine thymoma.

T-2 toxin (T-2(4)), one of the trichothecene mycotoxins produced by various gerera of Fusarium spp., is a potent inhibitor to the syntheses of protein and DNA in mammalian cells. The selective cytotoxicity of T-2 toxin-conjugated anti-EL-4 monoclonal antibodies (T-2-mAb) was investigated against murine thymoma EL-4 cells in vitro and in vivo systems. At first T-2 was converted to T-2 hemiglutarate by glutaric anhydride. Then T-2 hemiglutarate was activated to 3-[4-(N-succinimidoxycarbonyl)-butyryl]-T-2 (T-2-G-OSu) by N-hydroxysuccinimide. Thus obtained T-2-G-OSu was conjugated with mAb specific for EL-4 cells. The T-2-mAb markedly inhibited the proliferation of cultured EL-4 cells, but no such cytotoxic effect was observed against irrelevant SP2/0 cells. The cytotoxicity of T-2-conjugated normal gamma globulin (T-2-nGG) against EL-4 cells was far less than that of the above T-2-mAb. Ammonium chloride and monensin, inhibitors of lysosomal enzymes, enhanced the cytotoxicity of T-2-mAb. The presence of both 2-deoxyglucose together with sodium azide, inhibitors of energy-dependent reaction, reduced the cytotoxicity of T-2-mAb. Therefore, the selective binding to the target cells followed by an energy-dependent endocytosis and an intracellular liberation of T-2 by hydrolysis may account for the cytotoxicity of the T-2-mAb. In mice pre-transplanted with EL-4 cells, T-2-mAb increased the mean survival time (MST) with a direct dosage dependence.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗