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Biomedical subjects

K Masuda

Publications and source records attributed to K Masuda.

At least 703 records · Page 39Linked to original sources
PubMed1982

Studies of glycogen-induced inflammation of mice. Dynamics of inflammatory responses and influence of antiinflammatory drugs and protease inhibitors.

The intraperitoneal injection of glycogen in the mouse resulted, shortly thereafter, in the accumulation of 14-23 million neutrophils in the peritoneal cavity and a four-fold increase in the numbers of circulating neutrophils. Preceding the influx of leukocytes, the exudation of plasma proteins and the chemotactic activity for mouse neutrophil in vitro increased in the peritoneal fluid. Among various protease inhibitors examined, chymostatin alone suppressed the plasma protein exudation. Indomethacin and dexamethasone reduced the accumulation of white cells and protein exudation. These nonsteroidal and steroidal antiinflammatory drugs were equally effective whether given simultaneously with or 60 min before glycogen or whether administered intraperitoneally or orally. Colchicine showed a suppressive effect on the leukocyte accumulation but enhanced the protein exudation.

Animals↗
PubMed1982

[The effect of vasoactive intestinal polypeptide on the eye (authors transl)].

Vasoactive intestinal polypeptide (VIP), in doses of 1, 3, 5, 10 and 30 micrograms dissolved in 10 microliters of physiologic saline, was injected into the anterior chamber of albino rabbit eyes, which had been pretreated with topical 0.5 percent indomethacin. While the blood pressure remained unchanged, the intraocular pressure (IOP) began to rise shortly after injection and reached a maximum in about 20 minutes. An evident dose-response relationship was established between the percentage IOP increase and the dose of VIP. The protein content of the aqueous humor also increased in a dose-dependent manner, and the increases in the IOP and protein content could be significantly correlated. The pupil diameter did not change significantly during the experiments. The sphincter and dilator muscle strips were dissected from the iris of the albino rabbit eye pretreated with 0.5 percent topical indomethacin and incubated in Krebs-Ringer's solution to which VIP was added. A dose-dependent relaxation was induced in the sphincter muscle strip under contraction by 10(-6) M carbachol and also in the dilator muscle under contraction by 3 x 10(-5) M phenylephrine. The ED50 was calculated to be 1.78 x 0.49 x 10(-8) M for the former and 1.91 +/- 0.44 x 10(-9) M (Mean +/- s.e.m.) for the latter muscle strip.

Animals↗
PubMed1982

Purification and characterization of spirosomes in Lactobacillus brevis.

Spirosomes, very find spiral particles, were isolated from a protoplastlysate of Lactobacillus brevis ATCC 8287 by differential centrifugation and purified further by potassium tartrate density gradient centrifugation. The purified spirosome preparation showed a maximum peak around 275 nm on the ultraviolet absorption spectrum and it consisted of about 94.5% protein. The buoyant density in CsCl of the spirosomes was 1.320 g/cm3. The spirosomes were composed mainly of a single protein (spirosin with an apparent molecular weight of about 95,000 as determined by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The protein of the spirosomes was found to be composed predominantly of neutral amino acids accompanied by approximately equal amounts of acidic and basic amino acids. The spirosomes showed one antigenic determinant in the immunodiffusion test. The spirosomes were readily degraded by the action or proteolytic enzymes and lost their antigenicity, but they were not affected by treatment with either deoxyribonuclease or ribonuclease. The spiral structure of the spirosome was also found to be disintegrated by treatment with 1 M guanidine hydrochloride, 4 M urea or 0.1% SDS, but not by the action of deoxycholate, nonionic detergents or mercaptoethanol, as observed in the electron microscope.

Amino Acids↗
PubMed1982

Antibody spectrum and anticomplementary activity of a plasmin-treated human immunoglobulin preparation.

A commercial plasmin-treated human immunoglobulin was studied for its antibody spectrum and anticomplementary activity. Except for a decrease in anti-vaccinia antibody titers in two of three paired samples collected before and after plasmin treatment, there was practically no fall in titers of diphtheria antitoxin and of antibodies to measles, rubella and mumps viruses. Among the three major fractions isolated from the preparation, the plasmin-resistant 7S IgG fraction showed the highest anticomplementary activity when tested by our routine method described in the "Japanese Minimum Requirements'. The Fab fraction showed moderate anticomplementary activity which was thought to be due to the selective consumption of C3. On the contrary, the Fc fraction was not found to be anticomplementary in our test method. In some of the above-mentioned features, the preparation seems to be different from the domestic product formerly studied by ourselves.

Antibodies↗
PubMed1982

Isolation, properties, and reassembly of outer sheath carrying a polygonal array from an oral treponeme.

The outer sheath carrying a polygonal array was isolated from an oral treponeme, Treponema sp. strain E-21, by disruption of cells by means of repeated freeze-thawing and by removal of flagella under acidic conditions followed by linear sucrose density gradient centrifugation. Electron microscopy revealed that the outer sheath was isolated as a triple-layered vesicle having a polygonal array, free of flagella and wall membrane complex. Using optical diffraction, negatively stained preparations of the outer sheath fragments showed that the polygonal array appeared to be composed of a hexagonal pattern with a predominant spacing of about 16.3 nm. The isolated outer sheath contained 49.7% protein, 30.8% total lipid, and 11.0% carbohydrate. Phospholipid comprised about 95% of the total lipid. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the outer sheath was composed primarily of one major protein with an apparent molecular weight of about 62,000. The material from the isolated outer sheath solubilized with 1% sodium deoxycholate was reassembled into vesicles having a roughly polygonal array upon removal of the detergent by dialysis against 10 mM Tris-hydrochloride buffer with or without Mg2+.

Bacterial Proteins↗
PubMed1982

Effects of substance P on the isolated iris sphincter muscle of the albino rabbit.

Effects of substance P on the isolated iris sphincter muscle of the albino rabbit were studied. The muscle was incubated in an organ bath containing Krebs' physiologic solution and the muscle tension was recorded with an isometric transducer. Substance P induced dose-dependent muscle contraction in the concentration range from 3 x 10(-11) to 3 x 10(-7) M and ED50 was estimated to be 3.7 x 10(-9) M. The muscle contraction was not antagonized by tropicamide, phentolamine, propranolol, chlorpheniramine, cimetidine, methysergide or baclofen. Tetrodotoxin (3 x 10(-7) g/ml) pretreatment did not change the muscle contraction induced by substance P. A retrobulbar capsaicin injection did not cause supersensitivity in the muscle response to substance P. These results indicate that the iris sphincter muscle contraction caused by substance P is not mediated by cholinergic-, adrenergic-, histamine- or serotonine-recepters and suggests that its action on the muscle is direct.

Animals↗
PubMed1982

Effects of vasoactive intestinal polypeptide (VIP) and cyclic-AMP on the isolated sphincter pupillae muscles of the albino rabbit.

Iris sphincter muscle strips were dissected from the albino rabbit eye pretreated with 0.5% topical indomethacin and incubated in a Krebs-Ringer solution. Vasoactive intestinal polypeptide (VIP) was added to the incubation medium, and the effects on the tension of the sphincter pupillae muscles and the cyclic AMP (c-AMP) level in the muscles were correlated. The c-AMP level in the muscles was determined by a radioimmunoassay method. VIP induced a relaxation of the sphincter muscles and a positive correlation was found between the VIP effects and the c-AMP levels. The ED50 was calculated to be 3.72 X 10(-9)M. A significant increase in the c-AMP level occurred prior to the onset of muscle relaxation after VIP treatment (10(-7)M), and a peak level of c-AMP was reached when the relaxation was almost completed. The sphincter muscles were treated with a c-AMP phosphodiesterase inhibitor, 1-methyl-3-isobutylxanthine (MIX) (10(-5)M), 10 minutes prior to the experiment. This pretreatment enhanced the relaxation of the muscles induced by VIP.

1-Methyl-3-isobutylxanthine↗
PubMed1982

[Computation of a radiodosage equivalent of the effect of bleomycin].

The responses of in vitro cultured mammalian cells to X-rays and bleomycin were compared for establishing a general rule to convert X-ray dose to bleomycin dose for a given biological effect. There was no significant difference in the radiosensitivities according to cell lines used in this experiment, while the responses of cells to bleomycin varied from cell to cell. The X-ray dose-response curves for the cells were convex upward if plotted on a semilogarithmical scale, while bleomycin dose-response curves were convex downward. These results indicated that the ratio of X-ray dose and bleomycin dose required for a comparable biological effect would vary with the X-ray dose and from cell to cell. Preliminary treatment with bleomycin sensitized mammalian L5 cells to X-rays. When the cells were exposed to bleomycin following irradiation, no significant synergestic effect was observed, in spite of the fact that the bleomycin dose was sufficient to result in a survival of 4.5%.

Adolescent↗
PubMed1982

[Bacteriological and clinical evaluation of piperacillin in the field of obstetrics and gynecology].

In vitro activity of piperacillin (PIPC) against 150 recent clinical isolates from obstetric and gynecologic infections was performed in comparison with sulbenicillin (SBPC), cefmetazole (CMZ), cefotiam (CTM) and cefsulodin (CFS). At 6.25 micrograms/ml PIPC inhibited 93% of S. epidermidis, 86% of S. faecalis, 67% of E. coli and 80% of Klebsiella. At 0.2 microgram/ml PIPC inhibited 100% of Peptococcus, 73% of Peptostreptococcus and 100% of B. melaninogenicus group. At 3.13 micrograms/ml PIPC inhibited 71% of B. fragilis 9 strains, B. distasonis 3 strains, B. thetaiotaomicron 1 strain, B. ovatus 1 strain. PIPC was constantly more active than SBPC, and it was especially more active against S. faecalis, Peptococcus, Peptostreptococcus and B. melaninogenicus group than other antibiotics. These findings show that PIPC is a broad spectrum penicillin against both Gram-positive and Gram-negative organisms including anaerobic organisms. PIPC was administered to 5 patients intravenously and all cases proved to be effective. No side effects and no abnormalities in laboratory findings were observed. These results suggest that PIPC may be highly effective in the treatment of bacterial infections.

Adult↗
PubMed1982

[Fundamental and clinical studies of cefotaxime during the perinatal period in pregnant women].

Fundamental and clinical studies of cefotaxime (CTX) were carried out in pregnant women. The following results were obtained. CTX was more rapidly eliminated from the serum of pregnant women than that of adult males. Urinary excretion of CTX in pregnant women was comparable to that in nonpregnant women and adult males. Passage of CTX to the embryo, fetus and fetal appendages was minimal. Peak amniotic fluid concentration (9.8 mcg/ml) was attained at 3.5 hours after administration of CTX and gradually declined thereafter. This amniotic fluid concentration was sufficiently higher than reported MIC90 of CTX against E. coli strains. CTX was used in the treatment of 6 pregnant patients with acute pyelonephritis and 2 with puerperal infections. The bacteriological and clinical responses were both 100%. Since passage of CX into the amniotic fluid is favorable, CTX can be expected to be effective for the prophylaxis of intrauterine amniotic infection associated with early rupture of the membrane. CTX was used in the treatment of a neonate with purulent meningitis. The clinical response was effective. CTX did not cause any noteworthy adverse reactions or laboratory data abnormalities in our patients or neonates.

Adult↗