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Biomedical subjects

E Hosoi

Publications and source records attributed to E Hosoi.

45 records · Page 3Linked to original sources
PubMed1985

Inhibitory action of somatostatin on meiotic maturation of cultured porcine follicular ova.

To investigate the physiological importance of somatotrophin release-inhibiting factor (SRIF), effects in vitro of synthetic SRIF 14 on germinal vesicle breakdown (GVB) of cultured porcine follicular ova were studied. The proportion of ova with GVB decreased gradually and significantly with increasing concentrations of SRIF 14 in the range from 6 X 10(-12) to 6 X 10(-7) M during a 22 h period of culture. The inhibitory effect was apparent for the period between 14 and 22 h in the course of culture but was reversed by a concomitant addition of anti-SRIF to the medium. Neither synthetic oxytocin, vasoactive intestinal polypeptide nor substance P exerted any inhibitory or stimulatory action on GVB. These results suggest a limited but definite inhibitory action of SRIF on GVB of porcine ova.

Animals↗
PubMed1984

Co-storage and co-secretion of somatostatin and catecholamine in bovine adrenal medulla.

Co-storage and co-secretion of somatostatin (SRIF) and catecholamine (CA) were demonstrated using bovine adrenal medulla. In the experiment of retrograde perfusion system of isolated adrenal gland, the basal concentration of immunoreactive (IR)-SRIF was 20 pg/4 ml/min, but a significant increase of the value (142 pg/4 ml/min) was observed at 1-2 min after a brief infusion of acetylcholine (10 mM) and the marked release continued for over 6 min. Similar result was obtained for CA release. On gel-filtration chromatography of a soluble lysate of chromaffin vesicles prepared by differential and discontinuous sucrose density centrifugation, IR-SRIF was separated into three components with molecular sizes corresponding to prepro-SRIF (76.8% of the total immunoreactivity), SRIF28 (14.1%) and SRIF14 (9.1%).

Adrenal Medulla↗
PubMed1984

Evidence for existence of somatostatin-like immunoreactivity with molecular heterogeneity in porcine ovaries.

Measurement of somatostatin (SRIF) by RIA in porcine ovarian tissues after removal of the follicular fluid revealed the existence of immunoreactive (IR) SRIF at concentrations of 2.2 +/- 0.6 ng/g wet weight (mean +/- SD). On gel chromatographic analysis of ovarian extracts one major and two minor components with SRIF-like immunoreactivities have been detected. The major component comprised 59.5 +/- 15.1% of the total IR-SRIF and was coeluted with synthetic tetradecapeptide (SRIF 14). The two other components seemed to have almost the same molecular weights as synthetic octacosapeptide (SRIF 28) (25.1 +/- 10%) and pro-somatostatin (15.4 +/- 5.5%), respectively. It is concluded that SRIF in porcine ovaries is heterogeneous, comprising SRIF 14 as a major component, as well as larger forms of SRIF which probably represent SRIF precursors.

Animals↗
PubMed1983

Fetal and maternal plasma levels of immunoreactive somatostatin at delivery: evidence for its increase in the umbilical artery and its arterio-venous gradient in the feto-placental circulation.

The concentrations of immunoreactive somatostatin (IR-SRIF) in plasma samples taken from the umbilical artery (UA), umbilical vein (UV), and maternal antecubital vein (MV) were measured in 23 cases of normal delivery at term. High concentrations of IR-SRIF were detected in the plasma from the UA (mean +/- SD, 73.2 +/- 40.6 pg/ml), the value being about 2.5 times that in the UV (29.5 +/- 17.5 pg/ml; P less than 0.001). An arterio-venous gradient was observed in all 23 subjects. The plasma level of IR-SRIF in the MV (10.9 +/- 4.6 pg/ml) was significantly lower than those in the UA (P less than 0.001) and UV (P less than 0.001) and was almost the same as that in nonpregnant women (12.7 +/- 5.4 pg/ml). Chromatographic analysis of an extract of plasma from the UA gave only one peak of immunoreactive material, which was eluted in the same position as synthetic SRIF-14. A similar result was obtained in nonpregnant women. No correlation was found between the plasma level of IR-SRIF and that of GH, insulin, glucagon, or gastrin in the UA. The present findings suggest that the high concentration of IR-SRIF in the feto-placental circulation originates from the fetus and reflects a particular role of this peptide in the process of functional maturation of the neuroendocrine system in early human life.

Chromatography, Gel↗
PubMedDate not supplied

Overcoming of cross-resistance to the cell-killing activity of oxygen radicals in VCR-resistant hematologic cell lines with cyclosporin-A.

Anti-cancer agents like adriamycin, mitomycin-C, bleomycin, and etoposide express their cell-killing activity partly through oxygen radicals. Since vincristine (VCR)-resistant cells show cross-resistance to oxygen radicals, this study was designed to study whether the combined effects of oxygen radicals derived from hypoxanthine-xanthine oxidase plus enhancers of anti-cancer drugs such as verapamil (Ver), dipyridamole (Dip), and cyclosporin-A (Cy-A) overcome the cross-resistance for oxygen radicals in VCR-resistant human leukemia/lymphoma cell lines. We found that 3 micrograms/mL Cy-A enhances the cidal effect of oxygen radicals on two of five types of wild type and two of five VCR-resistant cell lines and it could overcome the cross-resistance to oxygen radicals in VCR-resistant cells. Neither Ver nor Dip showed any effect on the cidal activity of oxygen radicals. Thus, it was suggested that Cy-A works with different mechanisms from those of Ver or Dip, and Cy-A may be useful in reducing the doses of anti-neoplastic agents that exert their activity via oxygen radicals in the clinical treatment.

ATP Binding Cassette Transporter, Subfamily B, Mem↗