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Biomedical subjects

K Kojima

Publications and source records attributed to K Kojima.

At least 739 records · Page 41Linked to original sources
PubMed1981

Purification of anti-glycosphingolipid antibody and topological localization of glycosphingolipid on the cell surface of rat ascites hepatomas.

A simple method for the preparation of oligosaccharide-linked aminohexyl-Sepharose 4B (AH-Sepharose 4B) and its application to the purification of anti-glycosphingolipid antibody which is specific for the oligosaccharide moiety are described. The oligosaccharide, which was obtained from galactosyl(beta 1 leads to 3) N-acetylgalactosaminyl(beta 1 leads to 4)galactosyl(beta 1 leads to 4)glucosylceramide (asialo-GM1) by ozonolysis and subsequent alkali treatment, was covalently linked to the AH-Sepharose 4B by reductamination in the presence of NaBCNH3. Anti-asialo-GM1 antibody was purified by means of an affinity technique with the oligosaccharide-linked AH-Sepharose 4B. The antibody bound to the affinity adsorbent was eluted with 0.5 M NaSCN and 3.0 M NaSCN. Antibody with higher specific activity was recovered in the 3.0 M NaSCN fraction with 50% recovery of the activity of the starting material. The purified antibody was found to be quite specific for asialo-GM1. The presence of asialo-GM1 on the cell surface of free-type rat ascites hepatomas was confirmed by the immunofluorescence technique. The cell aggregates induced by the purified antibody were observed under a scanning electron microscope. The cell connection was found to occur at the tips of microvilli of the surface membrane. The localization of asialo-GM1 on the tips of the surface membrane was confirmed by means of the ferritin-conjugated antibody technique.

Animals↗
PubMed1981

Normalization of two-dimensional electrophoretic patterns of human plasma proteins and comparisons of cerebrospinal fluid and urine patterns in terms of the normalized map.

A "normalized map" of human plasma proteins, which illustrated the standard distribution pattern of the proteins, was prepared by comparing eight two-dimensional electrophoretic gels of normal human plasma. Phenotypes of several plasma proteins were detected. The pI and molecular weight of each spot in the normalized map were calculated and 84 spots out of 128 were identified or tentatively identified as known plasma proteins by several methods including micro amino acid analysis of the proteins extracted from the stained gel pieces. Human cerebrospinal fluid and urine protein patterns were compared with the normalized map and the positions of proteins characteristic of each body fluid sample were determined.

Blood Protein Electrophoresis↗
PubMed1981

Study of asialogangliosides on surface membranes of rat bone marrow cells and macrophages.

The presence of asialogangliosides on membrane surfaces of rat bone marrow cells and macrophages was studied by an immunological method using anti-glycolipid antibodies with high specificity. The antibodies against N-acetylgalactosaminyl(beta 1-4)galactosyl(beta 1-4)glucosylceramide (GA2), galactosyl(beta 1-3)N-acetylgalactosaminyl(beta 1-4)galactosyl(beta 1-4)glucosylceramide (GA1) and fucosyl(alpha 1-2)galactosyl(beta 1-3)N-acetylgalactosaminyl(beta 1-4)galactosyl(beta 1-4)glucosylceramide (Fuco-GA1) were prepared, and used for cytotoxicity testing and indirect staining by the immunofluorescence technique. In the cytotoxicity test, approximately 40-50% of rat intraperitoneal macrophages were killed by each of the anti-glycolipid antisera. This finding was confirmed by the indirect immunofluorescence staining method with the purified anti-GA2, anti-GA1, and also anti-Fuco-GA1 IgG. When a rat was preimmunized with bovine serum albumin, all macrophages induced in ascites fluid were found to possess GA1 by the staining method. Immature granulocytes were stained specifically with the anti-GA2 antibody. Granulocytes, myelocytes, and megakaryocytes were stained with the anti-GA1 antibody. Blastic myelocytes were stained with the anti-Fuco-GA1 IgG, but lymphocytes were not stained with any of these anti-asialoganglioside antibodies. From these observations, free-type cells such as macrophages and bone marrow cells were found to possess asialogangliosides as membrane components.

Animals↗
PubMed1981

Mutual relationship between antibiotics and resting spores of Bacillus subtilis: binding of cyclic polypeptide and aminoglycoside antibiotics to spores and their inhibitory effect on outgrowth and vegetative growth.

Not only cyclic polypeptide antibiotics such as polymyxin B, colistin and gramicidin S but also aminoglycoside antibiotics such as streptomycin, kanamycin, gentamicin and kanamycin derivatives combined with the resting spores of Bacillus subtilis and inhibited outgrowth or vegetative growth after germination. All the antibiotics other than gramicidin S were released from the resting spores and their inhibitory action was reversed by the addition of Ca2+ and Fe3+. As the above antibiotics have free amino (or guanidine) groups in common, it was assumed that such groups play an important role in binding of the antibiotics to the resting spores. Moreover, it was shown that protamine and poly-L-lysine were also bound to the resting spores and were released from them by Ca2+. On the other hand, free carboxyl groups had been demonstrated in the outermost surface of the resting spores in a previous study. Thus, we assume that the mode of binding of the antibiotics to the resting spores may be due to the formation of reinforced ionic bonds between amino (or guanidine) groups in the antibiotics and carboxyl groups on the spore surface.

Aminoglycosides↗
PubMed1981

Characterization of the sulfated monosialosyltriglycosylceramide from bovine gastric mucosa.

A sulfated monosialosyltriglycosylceramide was isolated from the lipid extract of bovine gastric mucosa in a yield of 2.52 microM/kg of wet tissue. The isolation procedure involved extraction of lipids with 0.4 M sodium acetate in methanol/chloroform/water, alkaline methanolysis, column fractionation on DEAE-Sephadex and silicic acid, and thin-layer chromatography. Based on the results of partial acid hydrolysis, sequential degradation with specific glycosidases, periodate oxidation, and methylation analysis of the native and partially degraded compound, the structure of this glycolipid is proposed to be: GalNAc beta 1 leads to 4(SO3H leads to 8Sia alpha 2 leads to 3)Gal beta 1 leads to 4Glc1 leads to 1Cer. The sialic acid of this glycolipid consisted of N-acetylneuraminic acid and N-glycoloylneuraminic acid, with the former being predominant component (71%) of the mixture.

Animals↗
PubMed1981

Effects of hyperthermia on cell surface charge and cell survival in mastocytoma cells.

Changes in the structure of the surface of mastocytoma cells were induced by hyperthermia and were investigated by means of cell electrophoresis. A decrease in the cell electrophoretic mobility was detected as early as 15 min after treatment at 42 degrees and progressed more rapidly under hypoxic conditions than under oxic conditions. Subsequent recovery of electrophoretic mobility at 37 degrees was dependent on the length of heat treatment and oxygenation. The surviving fraction of cells detected by their colony-forming ability and the fraction of electrophoretically recovered cells 24 hr after exposure to hyperthermia showed a good statistical correlation. It was suggested that the mechanism of electrophoretic mobility reduction by heating was the vertical translocation of hyaluronidase-sensitive charge from the peripheral layer into a deeper layer by combined use of specific enzymes and stepwise different ionic strengths. These results suggest the importance of irreparable changes of membrane conformation in the loss of colony-forming ability of heated tumor cells.

Animals↗
PubMed1981

Glucocorticoid-induced membrane alteration of thymocytes and thymic phagocytosis.

Electrophoretic mobility (EPM) of thymocytes progressively decreased after an i.p. injection of 10 mg hydrocortisone, and reached its lowest value 3 hr later. The degree of the decrease in the EPM of thymocytes was dependent on the dose of hydrocortisone. Thymic phagocytic cells began to ingest thymocytes in vivo 2 hr after hydrocortisone injection, and thymic phagocytosis continued up to 8 hr. Glucocorticoid-induced phagocytosis was also detected in vitro, i.e., primarily cultured thymic phagocytic cells ingested membrane-altered viable thymocytes from 10-mg hydrocortisone-treated mice 4 to 10 times more than control thymocytes. It was considered from these results that the decrease in the negative surface charge of thymocytes is closely associated with the phagocytosis of thymocytes by thymic phagocytic cells.

Animals↗
PubMed1980

Glycosphingolipids of guinea pig gastric mucosa.

Glycosphingolipids have beenn isolated from guinea pig gastric mucosa and their composition and content determined. The neutral glycospingolipids were found to consist of mono-, di-, tri- and pentaglycosylceramide. The acidic glycosphingolipids wee represented by galactosyl and lactosyl sulfatides, and GM4, GM3 and GD3 gangliosides. None of the analyzed glycolipids contained N-acetylglucosamine and fucose.

Animals↗