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Biomedical subjects

T Shinomiya

Publications and source records attributed to T Shinomiya.

107 records · Page 6Linked to original sources
PubMed1976

In vitro uptake and digestion of immune complexes containing guinea-pig IgG1 and IgG2 antibodies by macrophages.

The uptake and digestion of immune complexes by peritoneal macrophages from oil-stimulated guinea-pigs were studied using 125I-labelled guinea-pig IgG1 and IgG2 antibodies to hen ovalbumin. When the IgG1 or IgG2 antibody was incubated with homologous antigen at antigen-antibody ratios ranging from 0-01 to 10, the complexes produced were preferentially taken up by macrophages in the absence of complement and digestion by intracellular enzymes. The uptake and digestion of complexes reached a maximum at an antigen-antibody ratio of 0-1-0-5. In this respect, the IgG1 antibody was indistinguishable from the IgG2 antibody having a cytophilic activity. These observations suggest that some conformational changes in both the IgG1 and IgG2 antibodies or specific molecular arrangement in the lattice work of both the complexes may increase the strength of binding of complexes to macrophages, independently of the difference in biological activities between these two antibodies.

Animals↗
PubMed1975

Acceleration of intradermal catabolism of guinea pig IgG1 and IgG2 antibodies by challenge with antigen.

The intradermal catabolism of antibodies injected in guinea pigs to provoke skin reactions was studied using 125I-labeled guinea pig IgG1 and IgG2 anti-ovalbumin antibodies. Disappearance of both the IgG1 and IgG2 antibodies from injected sites was accelerated by intravenous injection of the antigen. The antigen-antibody complexes produced in vitro were also catabolized more rapidly than free antibodies, when estimated using 125I-labeled antibodies. On the other hand, the catabolism of normal IgG2 was not influenced by local anaphylactic reaction elicited by IgG1 antiovalbumin antibody coexisting at the sites. Therefore, the enhanced catabolism of antibodies on challenge was not caused by increased vascular permeability due to anaphylactic reactions, but by more rapid elimination of immune complexes formed at the sites. The Fc parts of IgG1 and IgG2 antibodies played an essential role in the enhancement of catabolism since the catabolism of the F(ab')2 fragments was not accelerated by complex formation with ovalbumin, but rather reduced.

Animals↗
PubMed1975

Defective pyocin particles produced by some mutant strains of Pseudomonas aeruginosa.

Mutants of Pseudomonas aeruginosa, defective in the production of active R-type pyocins, were isolated from pyocinogenic strains and their products were characterized. Polysheath-like structures were found in induced lysates of 29 out of 42 mutants. Two mutants (strain P15-16 and M189) were found to produce special defective particles, which were characterized in detail. The other 11 mutants did not produce significant amounts of any structure visible under an electron microscope. Serum blocking powers were found in lysates from P15-16 and M189 to significant amounts. Defective particle produced by strain P15-16 lacked the sheath component, whereas M189 had morphological defects at the junction between sheath and baseplate, and also in the architecture of baseplate. Both defective particles could adsorb to the surface of bacteria, that were sensitive to pyocin, at the tip of their fibers without killing cells. All M189 particles attached to the bacteria had the extended sheaths. Therefore, attachment to the bacteria by fibers is not sufficient to kill cells, and contraction of sheath must occur after the initial adsorption by fibers for pyocin to express its biological activity. Defective particles of strain P15-16, which was derived from strain P15 (a pyocin R1 producer), could be converted to active forms by an in vitro complementation reaction with extracts from certain mutants originated from strain PAO (a pyocin R2 producer). This result indicated the exchangeability of components between R-type pyocins belonging to the different groups.

Adsorption↗
PubMedDate not supplied

[Immunoelectrophoresis used for identification of blood stains in forensic medicine].

Conclusive evidence was obtained in this study that immunoelectrophoresis could be used in the identification of blood-stains in two particular cases: for diagnosis or approach to diagnosis of the age of a blood-stain, and for diagnosis of the human origin of a blood-stain that had been treated with petroleum products. Although many aspects should be investigated in more detail, it is certain that this method can be employed in combination with other methods.

Blood Stains↗
PubMedDate not supplied

[Gel electrophoresis of the alpha-2-Gc globulin group under various conditions].

Our experiments confirm the transformation of the group-specific component Gc into alpha 1-globulin. This transformation was more marked in blood samples subjected to repeated freezing-thawing procedures, and was very weak in samples subjected to repeated freezing-thawing procedures after mixing serum and red blood cells. The active factor responsible for this transformation was inhibited by heating at 56 degrees C for one minute in a water-bath. The transformation of the group-specific component was accomplished immediately by mixing serum and extract of platelets. The extract of platelets induced an increase in the rate of migration of all Gc components on immunoelectrophoresis, and it induced a decrease in the isoelectric point of all Gc components on Ampholine PAG plates with a pH range of 4 to 6.5. It induced a decrease in the rate of migration of all Gc components on polyacrylamide gel (7.5%) electrophoresis. A similar transformation was induced by homogenized fluid of cardiac muscle of cow and chicken, and pectoral muscle of the chicken.

Alpha-Globulins↗
PubMedDate not supplied

Hepatotoxicity of dichloromethane.

We studied hepatotoxicity of dichloromethane using primary cultures of parenchymal cells (hepatocyte) from adult rat livers. The production of carbon monoxide from dichloromethane increased with time, the increased cell number, and the concentration of dichloromethane. However, the carbon monoxide production per hepatocyte decreased with increasing cell density. When dichloromethane was in a high concentration, the metabolism of dichloromethane to carbon monoxide was extensively depressed, total glutamic-oxaloacetic transaminase (GOT) and mitochondrial GOT (m-GOT) levels in the cultured medium were extensively elevated, and the cultured hepatocytes were destroyed by dichloromethane. A case of accidental exposure to dichloromethane which occurred in Japan was also considered, and it is suspected that the inhalation of dichloromethane vapors in a high concentration for many hours may cause hepatotoxicity.

Animals↗
PubMedDate not supplied

Characterization of Newcastle disease viruses isolated from field cases in Japan.

Seven Newcastle disease viruses isolated in Japan from 1930 to 1984 were cloned on chicken embryo fibroblasts (CEFs) and characterized biologically. All seven produced two or more types of plaques on CEFs. The plaques were classified into four types. Plaque cloning was carried out five times, and 22 cloned viruses were established. The biological characters of the cloned viruses suggested that the strains contain different clones and that their clones are different even among close cases, such as G strain and H strain.

Animals↗