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Biomedical subjects

T Ofuji

Publications and source records attributed to T Ofuji.

At least 37 records · Page 2Linked to original sources
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

Influence of an antianxiety drug on hyperemesis diabeticorum.

The patient was a 37-year-old female teacher with hyperemesis diabeticorum and juvenile Type-I diabetes. At the age of 29 years, nausea and vomiting developed and secured at nearly weekly intervals. She was started on clotiazepam (15 mg/day). The vomiting was cured and psychological improvement was evident; her anxiety about diabetes was markedly reduced. An X-ray examination after the administration of clotiazepam showed that she was entirely free from marked hypoperistalsis and the severe retention of gastric contents which had been present before this treatment. The present case is a clear example of stress closely related to the pathogenesis of hyperemesis diabeticorum.

Adult↗
PubMed1982

A cerebellar ataxic rat produced by kainic acid and changes in concentration and turnover rates of catecholamines in discrete brain regions.

We made an animal model of cerebellar ataxia by injections of kainic acid into the cerebellar hemispheres on both sides of male rats. The histological and behavioral changes were observed at 4 weeks following the injections. The concentrations of catecholamines and the disappearance rates of alpha-MPT-induced catecholamines were measured in discrete regions of the brain of sham-operated and kainic acid-lesioned rats. A lowered dopamine disappearance rate was seen in the accumbens nucleus of the lesioned rats, but no change in norepinephrine. These findings suggest that the decrease in dopamine turnover in the accumbens nucleus is involved in the development of ataxic behavior.

Animals↗
PubMed1981

Differentiation of agonist conformation and antagonist conformation in multiple opioid receptors.

To differentiate the opiate (naloxone) receptor and the enkephalin receptor in rat brain, we solubilized the receptor molecules by detergent and determined the molecular weights by gel filtration. The receptor preparation was bound to [3H] naloxone or [3H] Met5-enkephalin, and was solubilized by Triton X-100. On gel chromatography with a Sepharose 6B column, the agonist and the antagonist conformation of opioid receptors eluted as molecules with the molecular weights of 240,000, and 120,000 and with Stokes' radii of 5.5 nm and 4.3 nm, respectively. Further, it was also disclosed that Na+ was bound to the antagonist conformation of opioid receptors but not to the agonist conformation.

Animals↗
PubMed1981

Effects of bromocriptine on receptor binding of methionine-enkephalin.

Bromocriptine inhibited the binding of methionine-enkephalin (ENK) to rat striatal synaptic membranes in a dose-dependent fashion. The bromocriptine IC50 was 16 micrometers. hill coefficients of bromocriptine were 0.7 and 0.3, suggesting that an allosteric effect was involved in bromocriptine inhibition of ENK binding to its receptor. These data suggest that at least a part of the therapeutic antiparkinsonian effect f bromocriptine is its allosteric effects on the ENK receptor, which influences the function of striatal dopamine neurons and/or of striatal cholinergic neurons.

Animals↗
PubMed1981

Discrete regional distributions of thyrotropin releasing hormone (TRH) receptor binding in monkey central nervous system.

Thyrotropin releasing hormone (TRH) directly influences central nervous system (CNS) function, independent of its pituitary action. Although these CNS effects have been behaviorally characterized, information is not yet available on the precise regional distribution of its receptor. TRH receptor binding was examined in the monkey CNS by the radioreceptor assay for clarifying the site of TRH action. TRH was bound to brain tissue membranes via high-affinity (Kd = 5.9 x 10(-9) M) and low-affinity (Kd = 11.2 x 10(-8) M) components. TRH receptor binding varied dramatically throughout the monkey brain, with more than 40-fold variation. The limbic system contained the greatest amount of binding. The next highest areas were the cerebral cortex, hypothalamus, interpeduncular nucleus and periaqueductal gray matter of the midbrain. Receptor binding was very low or not detectable in the medial thalamus, cerebellum, brain stem, spinal cord and white matter. These data suggest that TRH has an effect on the CNS via limbic system, cerebral cortex and midbrain.

Animals↗
PubMed1981

Vasopressin and CRF-ACTH in adrenalectomized and dexamethasone-treated rats.

Median eminence corticotropin-releasing factor (CRF) and arginine vasopressin (AVP) and pituitary and peripheral plasma adrenocorticotropin (ACTH) and AVP were measured in male Wistar rats 1 and 2 weeks after bilateral adrenalectomy (ADX), sham operation (SHAM) or dexamethasone-treatment (DEX). Median eminence AVP content was unchanged 1 week after ADX but was significantly elevated 2 weeks after ADX, whereas CRF activity was reduced at 1 week after ADX and returned to control range at 2 weeks. Anterior pituitary ACTH content was elevated but posterior pituitary AVP content was reduced at 1 and 2 weeks after ADX. Plasma ACTH was greatly elevated in ADX rats and reduced in DEX rats, whereas plasma AVP did not differ significantly between these two groups or the control group. When ADX and SHAM rats were laparotomized under ether, plasma ACTH increased greatly, but this elevation was prevented by DEX treatment. The plasma AVP level was elevated in all three groups 2.5 min after onset of stress but returned to the basal range at 20 min. Median eminence CRF and AVP and pituitary ACTH and AVP were not significantly changed after onset of stress. These results indicate that the vasopressin and CRF-ACTH responses were not consistent in the median eminence, pituitary and peripheral plasma and suggest that vasopression is not involved in the feedback and acute stress mechanism of CRF-ACTH secretion. However, we have to measure CRF activity and AVP concentration in the hypophysial portal blood to confirm this conclusion.

Adrenalectomy↗
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

Characterization of corticotropin releasing factor (CRF) and arginine vasopressin in median eminence extracts on sephadex gel-filtration.

Hypothalamic median eminence extracts (MEE) were subjected to gel filtration on Sephadex G-25 and G-75 columns to characterize the corticotropin releasing factor (CRF) in relation to arginine vasopressin (AVP). CRF activity was measured using monolayer cultured anterior pituitary cells, and AVP was measured by radioimmunoassay. Sephadex G-25 chromatography of AVP immunoreactivity of MEE (NIAMDD-Rat HE-RP-1) showed three peaks on elution with 0.1 N HCI and four peaks on elution with 0.2M acetic acid. But freshly prepared MEE showed only one peak on elution with 0.1 N HCI. These results suggest that AVP in NIAMDD-Rat HE-RP-1 is polymerized or aggregated on the Sephadex G-25 column, especially when eluted in 0.2M acetic acid. Two main peaks of CRF activity appeared consistently on both Sephadex G-25 and G-75 chromatography. One was near the void volume and the other was retarded. The small molecular CRF (small-CRF) peak was coeluted with immunoreactive AVP and 125I-AVP, on both chromatographies on elution with 0.1 N HCI. The large molecular CRF (big-CRF) appeared between the void volume and I-39 ACTH on Sephadex G-75 chromatography. Big-CRF from freshly prepared MEE had no AVP immunoreactivity. AVP showed CRF activity in pituitary cell cultures, but its CRF activity accounted for no more than 20% of the CRF activity of NIAMDD-Rat HE-RP-1. The log dose-response characteristics of the CRF activities of small-CRF and AVP differed. These results suggest that the median eminence has at least two substances with CRF activity: one is large molecular CRF, and the other is small molecular CRF which may have a vasopressin-like molecular weight. AVP may account for a part of the CRF activity of small molecular CRF but is not identical with genuine CRF.

Animals↗
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↗
PubMed1981

A double antibody radioimmunoassay for measurement of IgG, IgA and IgM synthesized by human lymphocytes in vitro.

To investigate cellular interactions between human T and B lymphocytes in various diseases, we established a technique to prove terminal differentiation of B lymphocytes into immunoglobulin synthesizing and secreting cells. We also established a double antibody radioimmunoassay to measure the amount of IgG, IgA and IgM synthesized and secreted in culture supernatants. Purified immunoglobulins were obtained from sera of patients with myeloma or macroglobulinemia. The peripheral blood lymphocytes from 25 normal individuals had the geometric mean synthetic rates of 1886 ng for IgG, 1607 ng for IgA and 1173 ng for IgM per 1 X 10(6) cells when cultured for nine days in the presence of pokeweed mitogen. The method is simple and sensitive, and is thought to be useful for examining human lymphocyte function in vitro.

Cells, Cultured↗