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Biomedical subjects

Y Mimura

Publications and source records attributed to Y Mimura.

At least 163 records · Page 9Linked to original sources
PubMed1986

Potentiation by retinoic acid of ornithine decarboxylase induction by phytohemagglutinin or phorbol 12-myristate 13-acetate in guinea pig lymphocytes.

Retinoic acid potentiated the increases in ornithine decarboxylase (L-ornithine carboxy-lyase [EC 4.1.1.17]) activity, [3H]difluoromethylornithine binding to ornithine decarboxylase, intracellular levels of polyamines and DNA synthesis in guinea pig lymphocytes stimulated with phytohemagglutinin. The stimulatory effect on the ornithine decarboxylase induction was dependent on the dose of retinoic acid and on the time of addition of the drug. Retinoic acid has to be added not later than 2 h after phytohemagglutinin to elicit the potentiation. Retinyl acetate also potentiated ornithine decarboxylase induction caused by phytohemagglutinin. Both of these retinoids augmented ornithine decarboxylase induction caused by phorbol 12-myristate 13-acetate. The half-life of ornithine decarboxylase activity estimated after addition of actinomycin D was longer in cells treated with phytohemagglutinin or phorbol 12-myristate 13-acetate together with retinoic acid than in cells treated with the mitogen alone. The half-life after addition of cycloheximide was not affected by retinoic acid. These results suggest that the retinoids are stimulators rather than inhibitors of ornithine decarboxylase induction caused by phytohemagglutinin or phorbol 12-myristate 13-acetate in guinea pig lymphocytes and that retinoic acid potentiates the enzyme activity at the transcriptional or posttranscriptional, but not at the post-translational stage.

Animals↗
PubMed1984

Purification to apparent homogeneity of inactive kallikrein from rat urine.

Inactive kallikrein was purified from rat urine by a procedure including ammonium sulfate fractionation, DEAE cellulose chromatography, phenyl-Sepharose CL-4B chromatography, and gel filtration on Sephadex G-100 and Sephadex G-75 columns. The resulting preparation was essentially homogeneous, as assessed by polyacrylamide gel electrophoresis. This preparation migrated as a single protein band on a SDS-polyacrylamide gel and the molecular weight was 41000. The purified material underwent marked activation by trypsin, but not by deoxycholate, Triton X-100, SDS or acidification. These results indicate that the purified inactive kallikrein is the precursor rather than a complex with a substance binding to the active form of kallikrein.

Animals↗
PubMed1984

Neutrophil collagenolytic activity in patients with Behçet disease.

Studies were made on neutrophil dysfunction in Behçet disease by examining collagenolytic activity in neutrophils. The collagenolytic activity of neutrophil was found to be significantly higher in patients during the attack phase of this disease than in patients during the remission phase, in patients with other forms of uveitis and in normal controls. Collagenase was present in the collagenolytic enzyme, which showed high activity in the attack phase. The molecular weight of this enzyme was similar to that of mammalian neutrophil collagenase.

Adult↗
PubMed1982

Studies on vitamin K-dependent factor deficiency during early childhood with special reference to prothrombin activity and antigen level.

8 young infants aged 14 days to 5 months with vitamin K-dependent factor deficiency were studied with special reference to prothrombin activity and antigen level. Among them, 3 infants had congenital bile duct atresia and 5 were breast-fed babies with severe hemorrhagic tendency of unknown cause. In the patients with both congenital bile duct atresia and breast feeding the ratio of prothrombin activity to prothrombin antigen was lower than 0.1. Furthermore, the arc of prothrombin antigen in these patients demonstrated a faster anodal shift than did normal prothrombin antigen on crossed immunoelectrophoresis. This abnormal prothrombin antigen was not consumed after recalcification of patient plasma, and absorbed poorly on BaSO4. In addition, the abnormal prothrombin antigen disappeared from the patient plasma within a few days after parenteral administration of vitamin K. These results suggest that this abnormal prothrombin is PIVKA-II.

Bile Ducts↗
PubMed1978

Thalamic control of spontaneous alpha-rhythm and evoked responses.

EEG, depth recordings from the thalamus, visual-evoked potentials, and readiness motor potentials were analyzed with a computer in 40 patients with involuntary movements and intractable pain who underwent stereotactic thalamotomy. It was demonstrated that there were significant correlations in alpha-rhythms between the ventrolateral (VL) nucleus and the frontocentral cortex, and also between the centromedian nucleus and the centroparietal cortex, with the phase difference of the cortex lagging behind the thalamus. Relationships between the thalamic VL nucleus and the frontocentral cortex were significant not only in alpha-rhythms, but also in evoked responses following photic stimulations, voluntary movements, and electrical thalamic stimulation. Thalamotomy produced a bilaterally decreased synchronization of the cortical alpha-rhythms, which recovered within 6 months.

Alpha Rhythm↗