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Biomedical subjects

Z Ota

Publications and source records attributed to Z Ota.

At least 253 records · Page 14Linked to original sources
PubMed1984

Synergistic interaction of corticotropin releasing factor and arginine vasopressin on adrenocorticotropin and cortisol secretion in Macaca fuscata.

Plasma immunoreactive CRF measured by radioimmunoassay decreased rapidly after intravenous injection of synthetic ovine corticotropin releasing factor (CRF) and showed a bi-exponential decay curve in five macaca fuscatas. Half lives of plasma immunoreactive CRF were 5.8 +/- 1.4 (Mean +/- SEM) min for the fast component and 38.3 +/- 2.4 min for the slow component. A bolus injection of 5 micrograms/kg CRF significantly increased the plasma cortisol level. CRF at 5 micrograms/kg induced a delayed response of ACTH and cortisol. Arginine vasopressin (AVP) at 0.5 micrograms/kg induced a slight increase in plasma ACTH and cortisol, but AVP at 0.1 micrograms/kg evoked no significant increase. When 0.5 micrograms/kg CRF and 0.1 micrograms/kg AVP were administered simultaneously, significant ACTH and cortisol responses occurred. The results indicate that CRF and AVP act synergistically to stimulate ACTH secretion in vivo.

Adrenocorticotropic Hormone↗
PubMed1984

Improvement in freezing phenomenon of Parkinson's disease after DL-threo-3, 4-dihydroxyphenylserine.

A 77-year-old man with Parkinson's disease of long standing, under treatment with L-DOPA and benserazide, was administered DL-threo-3, 4-dihydroxyphenylserine (DL-threo-DOPS), a precursor of norepinephrine, for 10 days. With this administration the patient's freezing phenomenon was remarkably improved, and his dysarthria also showed improvement. When DL-threo-DOPS was suspended, the frozen gait returned on the third day to almost the former level, even though he continued to receive L-DOPA and benserazide. After administration of DL-threo-DOPS, the CSF level of 3-methoxy-4-hydroxyphenylglycol (MHPG), a major metabolite of norepinephrine, was 127.5% of the pretreatment level. These observations suggest that DL-threo-DOPS can pass through the blood-brain barrier and change to norepinephrine, and that DL-threo-DOPS may be beneficial in the treatment of the freezing phenomenon of Parkinson's disease.

Aged↗
PubMed1983

[Effects of synthetic ovine corticotropin-releasing factor (CRF) on ACTH release in vitro].

The effect of the synthetic ovine corticotropin-releasing factor (CRF) on adrenocorticotropin (ACTH) release was examined by the perifusion method using rat anterior pituitary tissue and rat monolayer cultured pituitary cells. Quartered anterior pituitaries were placed in a chamber and perifused at a rate of 400 microliters/min with Dulbecco's modified Eagle Medium (DMEM, pH 7.4) bubbled with a mixture of 95% O2 and 5% CO2. The perifused medium was fractionated, and the ACTH concentration was measured by radioimmunoassay. In the monolayer cultured pituitary cells, the amount of ACTH released in the culture medium during three hours incubation was assayed by radioimmunoassay. ACTH was released from the perifused anterior pituitary in a dose-related manner by the pulse administration of CRF or arginine vasopressin (AVP) at the concentration of 1 ng/ml, 10 ng/ml and 100 ng/ml. A significant difference was not found between CRF- and AVP-induced ACTH release. In the monolayer cultured pituitary cells, synthetic ovine CRF induced ACTH release in a dose-related manner between 30 pg/ml and 30 ng/ml, but AVP induced a slight ACTH release. ACTH release was pulsatile during the continuous administration of 2.5 ng/ml of CRF for 150 min, although if gradually increased during the continuous administration of 10 ng/ml or 20 ng/ml of CRF. The continuous administration of AVP also caused pulsatile ACTH release at 10 ng/ml, but the ACTH release gradually decreased during the continuous administration of AVP. The interaction between CRF and AVP on ACTH release was examined by two methods. When CRF and AVP were given simultaneously, a mainly additive effect on ACTH release was observed. However, a low concentration of CRF seemed to potentiate AVP-induced ACTH release. These results show that both CRF and AVP have a significant CRF activity on the perifusion system, that AVP induced a slight ACTH release in monolayer cultured pituitary cells, and that CRF acts additively or potently with AVP to control the ACTH release from the anterior pituitary gland.

Adrenocorticotropic Hormone↗
PubMed1983

A specific radioimmunoassay for corticotropin releasing factor (CRF) using synthetic ovine CRF.

This newly developed specific radioimmunoassay for corticotropin releasing factor (CRF) had a sensitivity range of 25 pg/tube to 4 ng/tube. Intra and interassay coefficient of variation were 4.6% and 9.8%, respectively. Rat median eminence extracts showed a parallel dose response curve with synthetic ovine CRF and a significant cross reaction was not evident with other tested neuropeptides. The highest mean levels of CRF were found in the median eminence (6.61 ng/mg protein). Considerable amounts of CRF were found in the arcuate nucleus, paraventricular nucleus, dorsomedial nucleus, suprachiasmatic nucleus and ventromedial nucleus. The immunoreactive CRF of the rat medial basal hypothalamus coeluted with bioassayable CRF and with iodinated CRF on Sephadex G-75 chromatography. The results indicate that rat hypothalamus contains a CRF similar to ovine CRF.

Animals↗
PubMed1983

A simplified quantification method of complex-release activity using peroxidase as immune complex antigen.

The complement-mediated solubilization of precipitable immune complexes (complex-release activity) in serum specimens was determined by a simplified method using peroxidase as an immune complex antigen. The results correlated well with the hemolytic activity via the classical complement pathway and that via the alternative complement pathway. This simplified method proved to be reliable and useful.

Antigen-Antibody Complex↗
PubMed1983

Molecular sieve in bovine descemets membrane as revealed by negative staining.

Descemet's membrane was isolated from the corneas of cows and observed by electron microscopy after negative staining with 1% phosphotungstic acid solution, pH 7.2. Ultrastructurally, bovine Descement's membrane had a very regular hexagonal pattern. Nodes were connected to the six others around each of them by thin filaments to form a hexagon. The distance between the nodes was approximately 120 nm, the diameter of the nodes approximately 30 nm, and the width of the connecting filaments approximately 10 nm. Bovine Descement's membrane was a molecular sieve composed of nodes and filaments substantiating our molecular sieve theory of basement membranes.

Animals↗
PubMed1983

Detection of DR antigen on leukemic cells from a patient suffering from adult T-cell leukemia and progressive systemic sclerosis.

This report concerns an unusual case of adult T cell leukemia (ATL) complicated with progressive systemic sclerosis (PSS). The surface markers of peripheral blood mononuclear cells (PBM) and lymph node cells, both of which mainly consisted of leukemic cells, were examined. The effect of these cells on the pokeweed mitogen (PWM)-induced IgG synthesis by normal PBM also was studied. The leukemic cells formed rosettes with sheep red blood cells (SRBC; E) and expressed T cell antigen, Leu-1, and DR antigen. The detection of cell surface antigens was carried out by employing monoclonal antibodies against these antigens. We diagnosed this case as DR positive ATL. In terms of the immunoregulatory function of these leukemic cells, the co-culture experiments showed that these cells had some suppressive effect on the PWM-induced IgG production by allogeneic normal PBM.

Female↗
PubMed1981

Molecular sieve in rat tubular basement membrane as revealed by negative staining.

Rat tubuli were isolated both by the method of Krisko and by a modified method of Cook and Pickering; renal tubular basement membrane (TBM) was isolated by sonic disruption and by the method of Carlson. Using electron microscopy after negative staining, TBM of rat kidney isolated under these different conditions was shown to be a fine meshwork. Strands of the meshwork were interwoven, apparently enclosing pores to make up whole basement membrane. These findings are compared with our previous observation that glomerular and alveolar basement membranes were made up of a similarly fine meshwork.

Albumins↗
PubMed1981

Leukocytes in the glomerular capillary lumen in Masugi nephritis. A scanning electron microscopic study of freeze-cracked specimens.

Masugi nephritis was induced in rats by a single intravenous injection of rabbit anti-rat kidney serum, and studied with a scanning electron microscope. A characteristic finding was the presence of white cells, probably polymorphonuclear leukocytes, with many microspikes which penetrated through degenerated glomerular endothelial cells to be in direct contact with the glomerular basement membrane. This finding confirms the pathogenic role of leukocytes in glomerulonephritis induced by anti-glomerular basement membrane antibody.

Animals↗