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Biomedical subjects

Y Yanagihara

Publications and source records attributed to Y Yanagihara.

At least 235 records · Page 13Linked to original sources
PubMed1985

Separation of ascorbic acid, dehydroascorbic acid, diketogulonic acid and glucose by isocratic elution from a column of a hydrophilic gel.

High-performance liquid chromatography on an Asahipak GS-320 hydrophilic gel column with tartrate buffer (0.015 M, pH 3.0) containing 2 mM ethylenediaminetetraacetate and 0.05% beta-thiodiglycol as the eluent allowed the separation of glucose, diketogulonic acid, dehydroascorbic acid and ascorbic acid within 30 min. Fluorimetric monitoring of these compounds in the eluate with benzamidine at alkaline pH and at 90 degrees C in the presence of potassium sulphite allowed the determination of nanogram amounts of ascorbic acid, dehydroascorbic acid and diketogulonic acid. This method was applied to the determination of ascorbic acid in fruit juice.

2,3-Diketogulonic Acid↗
PubMed1985

Antitumor activity of Sphaerotilus natans and its slime fraction in mice.

Antitumor activity of the whole cell and slime of an aquatic sheathed bacterium, Sphaerotilus natans IAM 12068, against ascites form of Ehrlich carcinoma in ddY mice was investigated. Intraperitoneal injection of whole cells and the slime fraction showed remarkable antitumor activity against mice inoculated with 10(4) to 10(5) tumor cells, the slime fraction being more effective. To examine the chemical nature of the active principle in the slime fraction, separation by Sepharose 4B gel filtration was carried out and two fractions designated as GF-P-1 and GF-P-2, which are mainly composed of protein, carbohydrate, and lipid, were obtained. GF-P-1 fraction, which contains large amounts of fucose and unidentified sugar as neutral sugar, showed marked antitumor activity at half the dose of the slime fraction, whereas the antitumor activity of GF-P-2, which is composed mainly of protein, was weak. This finding indicates that GF-P-1 fraction of S. natans slime may be a main active principle. The consistently demonstrable antitumor activity of GF-P-1 was abrogated by treatment of mice with silica, an anti-macrophage agent, suggesting that the antitumor activity of GF-P-1 depends on the activation of macrophages.

Animals↗
PubMed1985

[Antiproliferative activities of interferon-alpha].

The antiproliferative activities of human lymphoblastoid interferon-alpha (MOR-22) against 22 cultured human cell lines were examined. Daudi cells and ACHN cells were highly sensitive to interferon compared with other human cells. The cell lines derived from renal and brain tumors showed concentration-dependent growth inhibition as determined from a 7-day growth curve but the concentration dependency was different in various cell lines. It was shown that longer exposure to interferon was necessary to obtain antiproliferative activity, and cell growth inhibition was completely reversible by washing the cultures. It was suggested that interferon had a time-dependent antiproliferative action.

Brain Neoplasms↗
PubMed1984

Sugar synthesis in Leptospira. I. Presence of glucosephosphate isomerase.

The presence of glucosephosphate isomerase, one of the key enzymes in carbohydrate metabolism, was confirmed for the first time in the cell-free extract of Leptospira biflexa. The glucosephosphate isomerase of L. biflexa was heat-labile and its optimum pH was about 8.5. The enzyme showed an optimal temperature of about 45 C but was more stable at 30 C. Km value of the enzyme was 5.6 X 10(-3)M. The activity of the enzyme was inhibited by the inhibitor, 6-phosphogluconate. From this study, the presence of a metabolic pathway, the phosphogluconate pathway, other than non-oxidative pentose phosphate pathway presented by Baseman and Cox was suggested.

Citric Acid Cycle↗
PubMed1984

Characterization of inhibitor to leptospiral hemolysin present in bovine serum.

Hemolysis by leptospiral hemolysin was strongly inhibited by bovine serum. The inhibitory activity was observed in the chloroform-methanol-soluble fraction of bovine serum. The inhibitor was eluted in a complex lipid fraction and was separated into two fractions (Fr. I and II) by silicic acid column chromatography. Fractions I and II inhibited approximately 75% and 95%, respectively, of hemolysis by leptospiral hemolysin. Fraction I was identified as phosphatidylethanolamine (PdE) by silica gel thin-layer chromatography (TLC). Two kinds of phospholipids (PLs) were detected in Fr. II by TLC. One was resistant to alkaline treatment and was identified as sphingomyelin (Spm), and the other was sensitive to such treatment and was identified as phosphatidylcholine (PdC). PLs, such as Spm, PdC, phosphatidylglycerol, PdE, phosphatidylserine and cardiolipin, inhibited hemolysis by leptospiral hemolysin, but phosphatidylinositol did not show any inhibitory activity. PLs lacking the amino group in the polar backbone of the molecules were more effective. From experiments using erythrocytes of various kinds of animals, it was revealed that the hemolytic sensitivity of mammalian erythrocytes to leptospiral hemolysin depended on the Spm content in the erythrocyte membrane. On the other hand, phospholipase C (PLase C) activity with Spm and PdC as substrates was detected in the culture supernatant of Leptospira. Therefore, leptospiral hemolysin was presumed to be PLase C, perhaps sphingomyelinase. The inhibitors of leptospiral hemolysin present in bovine serum were identified as PLs. PLs in bovine serum were suggested to function as inhibitors of the interaction between leptospiral hemolysin and the surface of the erythrocyte membrane.

Animals↗
PubMed1984

Sugar synthesis in Leptospira. II. Presence of glyoxylate cycle enzymes.

The presence and some properties of the key enzymes of the glyoxylate cycle, isocitrate lyase (threo-Ds-isocitrate glyoxylate-lyase, EC 4.1.3.1) and malate synthase (L-malate glyoxylate-lyase (CoA-acetylating) EC 4.1.3.2), were investigated in Leptospira biflexa. Isocitrate lyase activity was found for the first time in the organism. The enzyme was induced by ethanol but not by acetate. The optimum pH was 6.8. The activity was inhibited by phosphoenolpyruvate, a specific inhibitor of isocitrate lyase. The optimum pH of malate synthase of L. biflexa was about 8.5. The Km value for glyoxylate was 3.0 X 10(-3) M and the activity was inhibited by glycolate, the inhibitor. The results strongly suggested the presence of a glyoxylate cycle in Leptospira. The possibility that the glyoxylate cycle plays an essential role in the synthesis of sugars, amino acids and other cellular components as an anaplerotic pathway of the tricarboxylic acid cycle in Leptospira was discussed.

Carbohydrates↗
PubMed1984

Chemical compositions of cell walls and polysaccharide fractions of spirochetes.

Cellular polysaccharide fractions of various representative members of genera of the family Spirochaetaceae were obtained by the ammonium hydroxide extraction method. The sugar composition of the polysaccharide preparations was complex and many kinds of sugars such as rhamnose, fucose, ribose, xylose, mannose, galactose, and glucose were detected in all of the spirochetes tested. Of particular interest was the presence of 4-O-methylmannose as a constituent polysaccharide in members of the genus Leptospira. This sugar was not detected in the polysaccharides of Spirochaeta, Borrelia, and Treponema. The chemical compositions of cell wall fractions were also examined. 4-O-Methylmannose was detected in the cell wall polysaccharides of the genus Leptospira but not in cell walls prepared from the Spirochaeta, Borrelia, and Treponema. The diaminopimelic acid present in cell wall peptidoglycans of the genus Leptospira was meso-diaminopimelic acid (A2pm). The molar ratios of alanine, glutamic acid, A2pm, glycine, muramic acid, and glucosamine in leptospiral cell walls were found to be approximately 2:1:1:1:1:1. In contrast to the Leptospira, the peptidoglycans of genera Spirochaeta, Borrelia, and Treponema contained ornithine (Orn) but not A2pm. Since 4-O-methylmannose and A2pm were found in the cell wall fractions of genus Leptospira but not in Spirochaeta, Borrelia, or Treponema, it was suggested that the chemical compositions of the cell wall might become an important criterion for the chemotaxonomy of Spirochaetales.

Carbohydrates↗
PubMed1984

Phospholipases of Leptospira. I. Presence of phospholipase A1 and lysophospholipase in Leptospira biflexa.

The hydrolysis of phosphatidylethanolamine, phosphatidylcholine, lysophosphatidylcholine, and trioleoylglycerol by Leptospira biflexa strain Urawa was studied in vitro. Phospholipase A1 was identified by the formation of 32P- and 14C-labeled lysoderivatives from 32P-phosphatidylcholine, 32P-phosphatidylethanolamine, or 1-acyl-2-[1-14C]oleoyl-sn-glycero-3-phosphorylcholine. Phospholipase A1 activity was independent of lipase in the microorganism since 14C-labeled trioleoylglycerol was scarcely attacked under the same conditions in which the phospholipids were hydrolyzed. Lysophospholipase activity was also demonstrated using 32P- and non-labeled lysophosphatidylcholine. The activity of phospholipase A1 was found in a broad range of pH but no optimal pH was determined. The pH optimum of lysophospholipase was 8.0. Both enzymes were labile to heat. Phospholipase C activity, however, could not be detected because no radioactive di- and monoacylglycerol was found in the experiment with 1-acyl-2-[1-14C]-oleoyl-sn-glycero-3-phosphorylcholine as the substrate. It was inferred that phosphatidylethanolamine, which was the major component of phospholipids in leptospirae, was hydrolyzed serially by phospholipase A (A1 and/or A2?) and lysophospholipase to glycerophosphorylethanolamine via 2-acyl-type-lyso-derivative as one metabolic pathway of the substrate.

Hot Temperature↗
PubMed1984

[Immunopharmacological actions of neurotropin (4). Effect of neurotropin on mouse peritoneal macrophages].

It was reported that neurotropin (NSP), an extract isolated from the inflamed skins of rabbits inoculated with vaccinia virus, activates murine T cell functions participating in cell-mediated immunity. The present study was undertaken to examine the effect of NSP on plastic dish-adherent macrophages (M phi) from ddY mice in vitro. Total activities of beta-glucuronidase and N-acetyl-beta-D-glucosaminidase in resident peritoneal M phi was slightly enhanced when the M phi were cultured with NSP (10-1000 micrograms/ml) for 48 and 96 hr, but no enhancement was noted in 24 hr culture. Intracellular activity of lactate dehydrogenase (LDH) was also strongly enhanced in a dose-dependent manner by culturing with NSP for 48 and 96 hr. The enhanced LDH activity in the M phi cultured with NSP for 96 hr was completely inhibited by cycloheximide, an inhibitor of protein synthesis. In addition, consumption of glucose in the culture media by the M phi was also enhanced by culturing with NSP for 96 hr. Intracellular activity of LDH and glucose consumption of plastic dish-nonadherent cells from normal mouse peritoneal cells, however, was not enhanced by NSP in 96 hr culture. In regard to allogeneic M phi-mediated cytostatic activity to P815-X2 mastocytoma, NSP had no effect on cytostatic activities of the resident and thioglycollate-induced M phi, although NSP by itself dose-dependently inhibited the growth of P815-X2 mastocytoma without affecting cell viability. These results suggest that NSP biochemically activates mouse peritoneal M phi in vitro, but the M phi activated by NSP can not inhibit the growth of P815-X2 mastocytoma.

Adjuvants, Immunologic↗
PubMed1984

HPLC analysis of E. coli rRNA on ASAHIPAK GS-520 and nucleobases, nucleosides and nucleotides on ASAHIPAK GS-320.

High-performance gel filtration chromatography using packed column Asahipak GS-520 was employed to separate E. coli 23S, 16S and 5S rRNAs. Low-molecular-weight components of nucleic acid were separated with Asahipak GS-320. Concurrent, rapid analysis of nucleobases, nucleosides and nucleotides was obtained isocratically. The elution of these substances is also described.

Chromatography, High Pressure Liquid↗
PubMed1983

Direct action of cyclosporin A on human B-lymphocytes with regard to immunoglobulin production.

Highly purified preparations of human B-lymphocytes were cultured with or without cyclosporin A (CyA; 1 microgram/ml) for 8 days with pokeweed mitogen (PWM) in the presence of helper factors or with Epstein-Barr virus (EBV). The amounts of IgG, IgM, IgA and IgE produced in cultures were measured by radioimmunoassays or by reverse hemolytic plaque-forming cell assays. The results demonstrate that whereas CyA had a strong suppressive effect on the production of immunoglobulins (Ig) by PWM-activated B-cells, it had an enhancing effect on EBV-activated B-cells. It is concluded that CyA has a direct effect on human B-lymphocytes and that it may suppress or enhance their activation depending on the stimulant employed to trigger the cells.

B-Lymphocytes↗