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T Chiba

Publications and source records attributed to T Chiba.

At least 577 records · Page 32Linked to original sources
PubMed1986

Direct synaptic contacts of catecholamine axons on the preganglionic sympathetic neurons in the rat thoracic spinal cord.

Preganglionic sympathetic neurons were labelled by retrograde transport of horseradish peroxidase, while catecholamine axon varicosities were marked by the uptake of 5-hydroxydopamine in the intermediolateral nucleus of the rat. The direct synaptic contacts from the catecholamine axons to the preganglionic sympathetic neurons were demonstrated. Catecholamine axons formed symmetric synapses.

Adrenergic Fibers↗
PubMed1986

Electron spin resonance studies on a flavoprotein in neutrophil plasma membranes. Redox potentials of the flavin and its participation in NADPH oxidase.

Plasma membrane fractions of stimulated and resting cells were isolated from pig blood neutrophils. The midpoint redox potential (Em) of the membrane-bound flavin was determined potentiometrically by analysis of the flavin free-radical signal by electron spin resonance (ESR) spectroscopy. In both stimulated and resting cells, a peak position of the titration curve gave an Em value of -280 mV at pH 7.0 (Em7). The flavin free radical showed an ESR spectrum at g = 2.004 with a peak to peak width of 19 G, which indicates that the redox intermediate is a neutral semiquinone. Redox titrations were anaerobically examined at 25 degrees C with NADPH in place of dithionite. Addition of NADPH to plasma membranes of stimulated cells resulted in a rapid change in potential, accompanied by the formation of the ESR signal of flavin free radical. Computer simulation of the titration points gave an ambient midpoint potential of -280 mV (Em7). In contrast, those of resting cells showed a very slow change in potential and no g = 2.00 signal formation. Power saturation behavior of the ESR signal showed a marked difference between those of stimulated and resting cells. ESR characteristics of the flavin are discussed in relation to the membrane-bound NADPH oxidase.

Animals↗
PubMed1986

Amino acid residues complexed with eosin 5-isothiocyanate in band 3 protein of the human erythrocyte.

The amino-acid residues of band 3 protein taking part in the ionic interaction with an anion-transport inhibitor, eosin 5-isothiocyanate (EITC), were determined by pH titration. The plots of the absorbance of EITC-ghost system against pH reveal five equilibria, at pH 3.7, 6.4, 8.0, 11.0 and 13.1. Since the three equilibria, 3.7, 8.0 and 11.0, are representative of the EITC molecule, the others, 6.4 and 13.1, may be due to the interaction of EITC molecules with histidine and arginine residues, respectively. The same experiment using a reconstituted system of band 3-lipid vesicles gave results in good agreement with the EITC-ghost system. The intensity of the induced CD band at 530 nm of EITC molecules bound to ghosts was decreased by preincubation with arginine-specific reagents, phenylglyoxal and 1,2-cyclohexanedione, or histidine-specific reagents, diethylpyrocarbonate (DEPC) and p-diazobenzene sulfonate. The repression effects by these chemical modifiers were evaluated by measuring the concentrations which elicit 50% reduction. The histidine-specific reagents repressed the CD of EITC more effectively than the arginine-specific reagents. Furthermore, it was found that DEPC effectively inhibited the sulfate efflux from intact erythrocytes. These results suggest that the histidine residues participate in the anion-transport system of human red cells.

Anion Exchange Protein 1, Erythrocyte↗
PubMed1986

Characterization of the anion transport channel protein in human erythrocytes. Induced circular dichroism of inhibitors bound to the anion transport channel.

The induced circular dichroism (CD) of erythrocyte ghosts with anion-transport inhibitors has been studied. A ghost-EITC (eosin 5-isothiocyanate) system shows an induced CD spectrum at the wavelength region corresponding to the absorption bands of EITC. Also a ghost-EMI (eosin 5-maleimide) system shows induced CD, but has bands of opposite sign to the EITC system. From the change of the CD intensity, the number of EITC molecules bound to one erythrocyte was estimated to be about 1.4 X 10(6), being close to the number of band 3 copies per ghost. The CD spectra of EITC and EMI systems show that a configurational structure of the moiety anchoring the EMI molecule is the reverse to that of EITC. The preferred conformation of bound EITC may be twisted in a right-handed sense. From the signs of the induced CD bands in ghost-stilbene disulfonate systems, the chirality of twisted stilbene derivatives seems to be a left-handed sense, as is the case for the EMI derivative. The CD spectra of EITC in the presence of DIDS (4,4'-diisothiocyanostilbene-2,2'-disulfonate) shows that the binding site of EITC may not be identical with that of DIDS. The results observed in this study reflect the ternary arrangement of the functional amino groups in anion recognition sites.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1986

Correlation of mitochondrial swelling after capsaicin treatment and substance P and somatostatin immunoreactivity in small neurons of dorsal root ganglion in the rat.

Capsaicin injections into adult rats produced swelling of mitochondria in a population of small neurons of the dorsal root ganglia. Large neurons did not show the mitochondrial change. The mitochondrial swelling was confirmed to be a specific change produced by capsaicin treatment by the examination of different fixation conditions in both control and capsaicin-treated materials. Whether or not these mitochondrial changes occur in a subpopulation of small neurons which contain particular neurotransmitters was examined. The swelling of mitochondria was found in most substance P- or somatostatin-immunoreactive neurons and also in some non-immunoreactive small neurons. The present results indicate that the swelling of mitochondria is a specific change which may correlate with long-lasting desensitization of nociceptive neurons in the dorsal root ganglion after capsaicin treatment.

Animals↗
PubMed1986

Calcitonin gene-related peptide stimulates somatostatin release from isolated perfused rat stomach.

Effect of calcitonin gene-related peptide (CGRP) on somatostatin release was investigated on the isolated perfused rat stomach. Perfusion with CGRP (0.1 nM-100 nM) caused a significant and dose-dependent increase in effluent somatostatin levels. The somatostatin response to CGRP was rapid in onset and reversible immediately after the cessation of CGRP infusion. These findings suggest that CGRP stimulates the release of gastric somatostatin, thereby modulating gastric functions in rat.

Animals↗
PubMed1985

12-O-tetradecanoyl phorbol-13-acetate (TPA) stimulates somatostatin release from isolated perfused rat stomach.

Effect of TPA (12-O-tetradecanoyl phorbol-13-acetate), a potent tumor promoter, on immunoreactive somatostatin release was investigated using the isolated perfused rat stomach. TPA at the concentration as low as 20nM significantly stimulated the somatostatin release from isolated perfused rat stomach. The integrated net output of somatostatin induced by TPA was dose-dependent in a range of 5 - 50nM TPA. Since TPA is known to activate C-kinase specifically at a low dose (less than 20nM), these findings suggest that C-kinase system may be involved in the regulation of somatostatin release in rat stomach.

Animals↗
PubMed1985

Proteolytic substructure of brain myosin.

Individual bovine brain myosin molecules visualized by electron microscopy consist of two globular heads and a fibrous tail, like myosin molecules from other sources. Brain myosin, however, showed much lower solubility at moderate to high ionic strength (0.2 to 0.4 M KCl) than gizzard myosin, and the filaments formed at low ionic strength in the presence of Mg2+ were fairly resistant to low concentrations of ATP, by which gizzard myosin filaments were completely solubilized. Brain myosin was digested with low concentrations of papain, alpha-chymotrypsin, or trypsin, and the fragmentation patterns were analyzed by means of polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, sedimentation at low ionic strength, and electron microscopy of the fragments produced. The results indicate that all of the proteases cleave the myosin molecule primarily at sites located in the neck or in the head close to the neck, suggesting that the brain myosin molecule contains a hinge region or an open peptide stretch around these sites. The differences as well as the similarities between the proteolytic fragmentation patterns of brain myosin and other myosins are discussed.

Adenosine Triphosphatases↗
PubMed1985

Afferent and efferent connections of the medial preoptic area in the rat: a WGA-HRP study.

Afferent and efferent connections of the medial preoptic area including medial preoptic nucleus (MP) and periventricular area at the MP level were examined using WGA-HRP as a marker. Injections were performed by insertion of micropipette containing (1) small amount of HRP powder or (2) dryed HRP solution for 24 to 48 hr until the fixation or for 5 min respectively. Dorsal and ventral approaches of injection micropipettes were performed and the results were compared. Previously reported reciprocal connections with lateral septum, bed nucleus of the stria terminalis, medial amygdaloid nucleus, lateral hypothalamic nucleus, paraventricular hypothalamic nucleus, ventromedial hypothalamic nucleus, arcuate nucleus, supramammillary nucleus, central gray at the mesencephalon, raphe dorsalis, raphe medianus, and lateral parabrachial nucleus have been confirmed. In addition, we found reciprocal connections with septo-hypothalamic nucleus, amygdalo-hipocampal nucleus, subiculum, parafascicular thalamic nucleus, posterior thalamic nucleus at the caudo-ventral subdivision, median preoptic nucleus, lateral preoptic nucleus, anterior hypothalamic nucleus, periventricular area at the caudal hypothalamic level, dorsomedial hypothalamic nucleus, posterior hypothalamic nucleus, dorsal and ventral premammillary nucleus, lateral mammillary nucleus, peripeduncular nucleus, periventricular gray, ventral tegmental area, interpeduncular nucleus, nucleus raphe pontis, nucleus raphe magnus, pedunculo-pontine tegmental nucleus, gigantocellular reticular nucleus and solitary tract nucleus. The areas which had only efferent connections from MP were accumbens, caudate putamen, ventral pallidum, substantia innominata, lateral habenular nucleus, paratenial thalamic nucleus, paraventricular thalamic nucleus, mediodorsal thalamic nucleus, reuniens thalamic nucleus, median eminence, medial mammillary nucleus, subthalamic nucleus, pars compacta of substantia nigra, oculomotor nucleus, red nucleus, laterodorsal tegmental nucleus, reticular tegmental nucleus, cuneiform nucleus, nucleus locus coeruleus, and dorsal motor nucleus of vagus among which substantia innominata and median eminence were previously reported. Efferent connections to the nucleus of Darkschewitsch, interstitial nucleus of Cajal, dorsal tegmental nucleus, ventral tegmental nucleus, vestibular nuclei, nucleus raphe obsculus were very weak or abscent in the ventral approach while they were observed in dorsal approach. Previously reported afferent connections from dorsal tegmental nucleus, cuneiform nucleus, and nucleus locus ceruleus were not detected in this study.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

Prognostic subgroups for undifferentiated neuroblastoma: immunohistochemical study with anti-S-100 protein antibody.

Pathologic prognostic factors in 36 undifferentiated neuroblastomas were studied by an immunohistochemical staining technique with anti-S-100 protein antibody. Nuclear abnormalities of neuroblastic cells (mitosis and karyorrhexis/5,000 cells [MKI]), the incidence of S-100 protein-positive cells in the supportive stroma, and the age of the patients at diagnosis were analyzed both individually and in combination. Based on the evaluation of these factors, two prognostic subgroups were identified for these tumors. Tumors for which the prognosis was good (all nine patients alive) occurred in younger patients (younger than 1.5 years), showed low (less than 100) or intermediate (100 to 200) MKI, and had positive to intensely positive staining for S-100 protein. Cases in which the prognosis was poor (7 per cent survival) had single or multiple factors of high (greater than 200) MKI and/or absent or weak staining for S-100 protein and/or older age (older than 1.5 years) at diagnosis. These results were compared with other clinical information.

Age Factors↗
PubMed1985

Effect of cetiedil on the superoxide-generating system of porcine neutrophils.

Cetiedil, alpha-cyclohexyl-3-thiopheneacetic acid 2-(hexahydro-1H-azepin-1-yl)-ethyl ester, was found to inhibit the generation of superoxide (O2-) by porcine neutrophils exposed to various stimulators. The concentration of cetiedil required for 50% inhibition was about 45 microM when neutrophils were stimulated by phorbol myristate acetate. Cetiedil not only decreased the rate of generation of O2-, but prolonged the lag time prior to the production of O2-. The inhibitory effect of cetiedil on the O2(-)-generating activity of the NADPH oxidase in the membrane vesicles was less than that on whole cells; the concentration of cetiedil necessary for 50% inhibition was about 250 microM. To study the mechanism of cetiedil's effect on the membrane, the transmembrane potential of neutrophils and the intracellular free Ca2+ concentration were monitored by using fluorescence probes, diS-C3-(5), and quin-2, respectively. Cetiedil caused depolarization of the membrane potential and increased the intracellular free Ca2+. These results indicate that integrity of ionic distribution is necessary to activate the O2(-)-generating system of neutrophils.

Animals↗
PubMed1985

Accurate localization of insulinoma using percutaneous transhepatic portal venous sampling--usefulness of simultaneous measurement of plasma insulin and glucagon levels.

By means of percutaneous transhepatic portal venous sampling (PTVS), plasma insulin and glucagon levels were determined simultaneously at various sites of the hepatic portal venous system in two patients with insulinoma and four patients without. In the two cases of insulinoma, an obvious rise of insulin concentration was observed at the vicinity of the tumour, while glucagon levels were not elevated in the blood samples showing an insulin peak. In the remaining four cases without evidence of insulinoma, significant step-ups of plasma insulin occurred in the splenic vein as well, but were accompanied with concomitant elevation of plasma glucagon levels in the same blood samples. Thus, by measuring insulin alone, false positive data may frequently be obtained when PTVS is performed on patients with suspected insulinomas. The simultaneous measurement of insulin and glucagon might be helpful in avoiding such errors.

Adenoma, Islet Cell↗