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Biomedical subjects

Y Aoki

Publications and source records attributed to Y Aoki.

At least 757 records · Page 42Linked to original sources
PubMed1983

Studies on Brugia pahangi in inbred hamsters. 1. Susceptibility of inbred GN and APG hamsters.

The susceptibility of inbred GN and APG hamsters to Brugia pahangi infection was studied. Male GN hamsters infected subcutaneously with 100 infective larvae showed 100% patency with the average prepatent period of 69 days. The average microfilarial density was 148/40 c.mm at 26 weeks and reached 1,000/40 c.mm at days 280. The rate of adult recovery was as high as 36%. Most worms were recovered from the heart and lungs (46%) and testes (40%). The male GN hamster-B. pahangi model could be a good substitution for the jird-B. pahangi model. Female GN and male APG hamsters seemed to be less susceptible than male GN hamsters. However, they could still be a better alternative to outbred hamsters due to their high rates of patency (92 and 100%), relatively high microfilarial densities (31 and 39/40 c.mm at 26 weeks) and reasonable rates of adult recovery (23.5 and 17.2%).

Animals↗
PubMed1983

Karyotypes of Brugia pahangi and Brugia malayi (Nematoda: Filarioidea).

Using air-dried preparations of the testis and ovary, karyotypes were analyzed and compared to each other in two species of filarial parasites, Brugia pahangi and B. malayi. Both species had a diploid number of 10 chromosomes and were karyotypically very similar. C-banding analyses disclosed that the sex-determining mechanism of these species was of the XY-XX type, where the X chromosome was the largest, and the Y chromosome was of medium-size.

Animals↗
PubMed1982

A study of a female with congenital sideroblastic anemia.

A female infant with congenital refractory sideroblastic anemia is described. A marked reduction of delta-aminolevulinic acid (ALA) synthetase activity of erythroblasts was noticed with and without treatment of pyridoxal phosphate. Mitochondrial neutral protease activity of erythroblasts, which inactivates specifically the apo form of ALA synthetase, was normal and the sensitivity of apo form of ALA synthetase to the neutral protease was also normal. It was speculated that the reduction of ALA synthetase activity is not due to the high speed of destruction, but rather due to the impairment in production of ALA synthetase, which could explain the unresponsiveness to pyridoxine therapy in this case.

5-Aminolevulinate Synthetase↗
PubMed1982

Distribution and characterization of corticotropin-releasing factor and arginine vasopressin in rat hypothalamic nuclei.

Corticotropin-releasing factor (CFR) was bioassayed and arginine vasopressin (AVP) radioimmunoassayed from punched-out hypothalamic nuclei. The highest concentration of CFR was found in the median eminence (ME), followed by the paraventricular nucleus (PVN), supraoptic nucleus (SON), suprachiasmatic nucleus (SCN), arcuate nucleus (ARC), dorsomedial nucleus (DMN) and ventromedial nucleus (VMN). The AVP concentration was in the order of ME, SON, PVN, SCN, ARC, VMN and DMN. Sephadex G-25 gel filtration of the ME extracts showed one peak for AVP and two peaks for CRF. One CRF peak appeared on the void volume (big CRF) and the other (small CRF) was coeluted with AVP. Gel filtration of the PVN and SON extracts showed one peak for AVP but three or four peaks for CRF. The addition of anti-AVP serum (AVP-AS) to pituitary cell cultures reduced the CRF activities of AVP and ME extracts by approximately 80 and 40%, respectively. When the small CRF fraction of ME extracts was treated with AVP-AS on affinity chromatography, the unbound fraction (AVP-free) still showed significant CRF activity. Re-examination of CRF concentration using AVP-AS showed that it was still highest in ME, but was significantly higher in PVN than in SON, SCN and ARC. These results suggest that the PVN is an important nucleus for producing corticotropin-releasing hormone.

Animals↗
PubMed1982

Medullasin enhances human natural killer cell activity.

Medullasin, a new serine protease found in bone marrow cells, increased markedly human natural killer cell activity. Whereas the natural killer cell activity measured immediately after the treatment with medullasin remained almost on the same level as the control, an incubation at 37 degrees C for several hours increased markedly the natural killer cell activity of the lymphocytes treated with medullasin. Enhancement of the natural cytotoxicity was caused by the treatment with physiologic concentrations of the protease (5-20 micrograms/ml). Inhibitors of medullasin such as phenylmethylsulfonyl fluoride and elastatinal prevented the activation of natural cytotoxicity. Depletion of lymphocytes bearing Fc receptors for IgG abolished the enhancement of natural killer cell activity by medullasin. Interferon activity was not detected in the supernatant of lymphocyte cultures stimulated with medullasin. The medullasin enhanced further the natural killer cell activity of lymphocytes stimulated with interferon. Medullasin activity was detected neither in unstimulated nor stimulated (by concanavalin A or phytohemagglutinin) human lymphocytes. The protease was released easily from human mature granulocytes into culture medium. It is considered from these results that the level of human natural killer cell activity is regulated by medullasin released by mature granulocytes.

Cytotoxicity, Immunologic↗
PubMed1982

The effect of serotonin agonist 1-(trifluoromethylphenyl)-piperazine on corticotropin releasing factor and arginine vasopressin in rat hypothalamic nuclei.

Effects of 1-(m-trifluoromethylphenyl)-piperazine, a serotonin agonist, were examined on rat plasma levels of adrenocorticotropin (ACTH) and arginine vasopressin (AVP), and on hypothalamic contents of corticotropin releasing factor (CRF) and AVP, to investigate the role of brain serotonin in ACTH regulation. Both plasma ACTH and AVP levels increased markedly 30 min after injection of the compound and were still elevated at 80 min. CRF and AVP contents in the median eminence decreased 30 min after injection but returned to the basal levels by 80 min. The AVP content in the supraoptic nucleus was elevated 80 min after injection. The CRF and aVP content did not significantly change in the paraventricular, suprachiasmatic and arcuate nuclei. Serotonin or 1-(m-trifluoromethylphenyl)-piperazine did not stimulate the release of ACTH in pituitary cell cultures. These results suggest that both CRF and AVP were secreted into the portal vessels by 1-(m-trifluoromethylphenyl)-piperazine to release ACTH from the anterior pituitary and that both the ACTH and AVP release were stimulated via the brain serotonergic mechanism.

Adrenocorticotropic Hormone↗