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Biomedical subjects

S Kumazawa

Publications and source records attributed to S Kumazawa.

At least 37 records · Page 2Linked to original sources
PubMed1993

Benign, non-parasitic hepatic cyst causing obstructive jaundice.

A 71-year-old woman with an hepatic cyst that led to obstructive jaundice is reported. Percutaneous intracystic fluid aspiration was useful in transiently decreasing the jaundice. Thereafter, the cyst was extirpated, and was found to be large (nearly 10 cm), benign and non-parasitic. This patient and 15 similar cases reported in the literature, indicate that the risk of jaundice induced by a simple hepatic cyst is related to its size (larger than 10 cm) and location near the common hepatic duct.

Aged↗
PubMed1993

Effects of aibellin, a novel peptide antibiotic, on rumen fermentation in vitro.

A new icosapeptide, aibellin, markedly modified rumen fermentation in vitro. Batch culture experiments with mixed rumen microorganisms showed that 12.5 to 25 mg/L of aibellin enhanced propionate production and reduced methanogenesis without significantly affecting production of total VFA, protozoal survival, or cellulose digestion. Aibellin had essentially the same effects in continuous culture with hay powder and concentrate. Monensin (5 mg/L) had similar effects on propionate production and methanogenesis, but total VFA, protozoa, and cellulolysis were decreased even by this low concentration of monensin. Commercially available peptide antibiotics also were compared with aibellin. Of the antibiotics examined, only graminicidin D (7.5 to 15 mg/L) enhanced propionate production and reduced methanogenesis. However, gramicidin D decreased total VFA, protozoa, and cellulolysis even at 7.5 mg/L. Alamethicin (7.5 to 15 mg/L), which resembles aibellin in its structure, did not increase propionate production but raised the percentage of propionate because of reduced production of total VFA. Alamethicin depressed methanogenesis but also decreased protozoal survival and cellulose digestion. These in vitro experiments indicate that aibellin could be a useful and potent modifier of rumen fermentation.

Alamethicin↗
PubMed1993

Dactylfungins, novel antifungal antibiotics produced by Dactylaria parvispora.

Novel antifungal antibiotics, designated as dactylfungins A (1) and B (3), were isolated from the culture broth of Dactylaria parvispora D500. Dactylfungins A and B were found to be new substances containing an alpha-pyrone and a gamma-pyrone ring, respectively, which conjoined with a polyalcohol moiety and a long side chain, based on NMR spectral analyses. The antibiotics were active against Candida pseudotropicalis and other fungi, with an MIC value at less than 10 micrograms/ml.

Antifungal Agents↗
PubMed1985

Comparative Amperometric Study of Uptake Hydrogenase and Hydrogen Photoproduction Activities between Heterocystous Cyanobacterium Anabaena cylindrica B629 and Nonheterocystous Cyanobacterium Oscillatoria sp. Strain Miami BG7.

Heterocystous filamentous cyanobacterium Anabaena cylindrica B629 and nonheterocystous filamentous cyanobacterium Oscillatoria sp. strain Miami BG7 were cultured in media with N(2) as the sole nitrogen source; and activities of oxygen-dependent hydrogen uptake, photohydrogen production, photooxygen evolution, and respiration were compared amperometrically under the same or similar experimental conditions for both strains. Distinct differences in these activities were observed in both strains. The rates of hydrogen photoproduction and hydrogen accumulation were significantly higher in Oscillatoria sp. strain BG7 than in A. cylindrica B629 at every light intensity tested. The major reason for the difference was attributable to the fact that the heterocystous cyanobacterium had a high rate of oxygen-dependent hydrogen consumption activity and the nonheterocystous cyanobacterium did not. The activity of oxygen photoevolution and respiration also contributed to the difference. Oscillatoria sp. strain BG7 had lower O(2) evolution and higher respiration than did A. cylindrica B629. Thus, the effect of O(2) on hydrogen photoproduction was minimized in Oscillatoria sp. strain BG7.

Journal Article↗
PubMed1983

Proton efflux coupled to dark H2 oxidation in whole cells of a marine sulfur photosynthetic bacterium (Chromatium sp. strain Miami PBS1071).

Whole cells of photoanaerobically grown Chromatium sp. strain Miami PBS1071, a marine sulfur purple bacterium, oxidized H2 in the dark through the oxyhydrogen reaction at rates of up to 59 nmol of H2 per mg (dry weight) per min. H2 oxidation was routinely measured in H2 pulse experiments with air-equilibrated cells. The reaction was accompanied by a reversible H+ efflux from the cells, suggesting an outward H+ translocation reaction coupled to H2 oxidation. The H+/e- ratio, calculated from simultaneous measurements of H2, O2, and H+ changes in the medium, varied with the cultures from 0.7 to 1.2. The ratio increased considerably when the backflow of H+ was taken into account. Anaerobic H2 uptake with 2,5-dimethyl-p-benzoguinone as an oxidant also showed a weak H+-translocating activity. No H+-translocating activity was detected with methylene blue as an oxidant. Carbonylcyanide 3-chlorophenylhydrazone (1 microM) stimulated H2 oxidation and abolished the associated H+ changes when H2 oxidation was observed in O2 pulse experiments with H2-Ar-equilibrated cells. However, the uncoupler inhibited both H2 oxidation and H+ changes when measurements were made in H2 pulse experiments with air-equilibrated cells. It is suggested that in this bacterium the susceptibility of hydrogenase to reversible O2 inactivation in situ is enhanced by the presence of uncoupling agents.

Benzoquinones↗
PubMed1978

Clinical evaluation of a pre-set ultrafiltration rate controller available for single pass and hemodiafiltration systems.

Introduction of high flux-type dialyzers, such as the RP-6, makes it necessary to devise an ultrafiltration rate controller for a single pass system. For this purpose, a new pre-set ultrafiltration rate controller has been developed and examined experimentally and clinically. The controller has twin chambers, each of which is divided into two symmetrical parts by a vertically-placed diaphragm. The diaphragm shifts repeatedly from right to left, aspirating in and driving out fresh or used dialysate alternately. If one removes a certain amount of used dialysate from a branch of the efferent line, negative pressure develops and aspirates an equal amount of water from the dialyzer. Therefore, extra dialysate obtained by a pump precisely reflects ultrafiltration rate. The controller has been used on five patients. The scheduled ultrafiltration rate was easily obtainable. The apparatus is also available for hemodiafiltration. Initial clinical trial has been promising.

Body Fluids↗
PubMed1977

Controlled ultrafiltration (UF) with hemodialysis (HD): analysis of coupling between convective and diffusive mass transfer in a new HD-UF system.

A convertible and versatile dialysis system consisting of a PMMA hollow fiber unit and UFR controller is shown to be useful for evaluating the effect of solute and fluid removal rates on adequacy of dialysis. Post-dilution mode where high UFR is applied to the patient with matching or comparable dilution rate is concluded to be most effective modification for enhancing the clearance for "middle molecules", without sacrificing the removal rates for the small solutes.

Creatinine↗
PubMedDate not supplied

In vitro electrochemical detection of wheat allergen using rat basophilic leukaemia (RBL-1) cells.

We have investigated an electrochemical method of detecting foods that cause an allergic reaction. Rat basophilic leukaemia (RBL-1) cells were sensitized with serum from a rat that was allergic to wheat. A sample containing the protein fraction of a food was added to the cells and incubated. The cells were immobilized on a membrane filter and attached to a basal-plane pyrolytic graphite electrode. When a potential was applied in the range 0-1.0 V relative to a saturated calomel electrode, an anodic peak current appeared at around 0.33 V. This peak current, attributed to serotonin, increased with time, and the maximum current (0.5 microA) was obtained 20-25 min of incubation. The response of the RBL-1 cells was specific to the protein fraction of wheat. The peak current increased linearly with increasing protein concentration in the range of 0.01-0.5 micrograms ml-1. These results suggest that the concentration of the protein bringing about the allergic reaction can be determined by cyclic voltammetry within 25 min. This method is more sensitive than the conventional skin tests.

Allergens↗