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Biomedical subjects

M Tokuda

Publications and source records attributed to M Tokuda.

At least 199 records · Page 11Linked to original sources
PubMed1982

Antimicrobial effect of human serum IgA.

Serum IgA, IgG and colostrum secretory IgA prepared from specimens pooled from a large number of human beings were shown to have measurable levels of antibodies against Escherichia coli, Pseudomonas aeruginosa, Klebsiella Pneumoniae, poliovirus, Coxsackie B virus, echovirus and influenza virus. Serum IgA exerted a bacteriostatic effect in vitro on E. coli and P. aeruginosa, which increased in the presence of the iron-binding proteins lactoferrin and transferrin. This bacteriostasis was reduced when the iron-binding proteins were saturated with iron. Similar results were obtained with IgG and secretory IgA. The bacteriostatic effect of serum IgA was also shown in vivo, in the peritoneal cavity of mice. The effect was suppressed by iron. Iron-chelating substances, siderophores, excreted by E. coli diminished the co-operative bacteriostatic effect of serum IgA and transferrin. Siderophore production by E. coli was inhibited in the presence of serum IgA, but not when serum IgA was deprived of specific antibody by absorption with E. coli. These results indicate that serum IgA has a potent bacteriostatic effect in co-operation with transferrin or lactoferrin because of the inhibitory effect of the specific antibody on siderophore production by E. coli.

Antibodies, Bacterial↗
PubMed1982

Factors inhibiting cell proliferation in rat liver cytoplasm.

Two factors from normal rat liver cytoplasm inhibited the proliferation of cultured L-929 fibroblasts. One was arginase, the other was a small molecular weight inhibitor stable to trypsin and heat treatment. The small molecular weight inhibitor inhibited the protein and DNA synthesis of L-cells. Inhibition of DNA synthesis was thought to be secondary to the inhibition of protein synthesis.

Animals↗
PubMed1979

Induction of indoleamine 2,3-dioxygenase in mouse lung during virus infection.

Indoleamine 2,3-dioxygenase [indoleamine: oxygen 2,3-oxidoreductase (decyclizing)] activity in the supernatant fraction (30,000 X g, 30 min) of mouse lung homogenate increased approximately 120-fold after infection with PR8 influenza virus. Both specific and total enzyme activities started to increase linearly from the 5th day after infection, reached the highest level around the 11th day, and then gradually decreased to normal values in about 3 weeks. Other enzymes in the lung, such as certain lysosomal enzymes and monoamine oxidase, did not change significantly throughout the experiments. The time course of the increase in the enzyme activity was quite different from that of virus replication in the lung (a peak by the 3rd day and persistence until the 9th day) or that of serum antibody content (started to rise on the 9th day). Rather, it appeared to be closely related to the infiltrations of mononuclear and lymphocytic cells. When mice were exposed to a higher dose of virus and did not recuperate, the time course of the increase of the enzyme activity was essentially identical to that seen with a low concentration of virus. A maximum stimulation of the enzyme activity in the lung occurred on the 9th day after infection; the increase was approximately 100-fold. However, serum antibody content was slight and virus titer in the lung remained high.

Amines↗
PubMed1979

Partial purification and biological activities and properties of chick growth factors.

Cellular stimulating factors on cell proliferation in the supernatants of chick embryo carcases and adult muscles were studied. There were plural stimulating factors in embryonic and adult muscular supernatants that promoted cell proliferation without any supplement of sera and other materials. Salting-out methods with ammonium sulfate, ethanol fractionation, and isoelectric precipitation were used to isolate the stimulating factors, and these three methods proved the presence of plural stimulants on cell proliferation in the supernatants of chick embryo and adult muscles. The stimulants had altered physico-chemical properties and biological activities due to embryological development. The embryonic stimulants enhanced the synthesis of DNA and protein remarkably, and RNA synthesis in whole cell systems slightly. The muscular stimulants enhanced protein synthesis without any stimulation of DNA and RNA synthesis. Partial purification of the stimulants from the ethanol fractions was performed by DEAE-cellulose chromatography and Sephadex gel chromatography.

Animals↗