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Biomedical subjects

E Ueno

Publications and source records attributed to E Ueno.

103 records · Page 6Linked to original sources
PubMed1981

[Effect of Bromovincamine on noradrenaline and 5-hydroxytryptamine contents, and glucose metabolism in rat brain: analysis using spontaneously hypertensive rats (SHR) (author's transl)].

Effects of Bromovincamine (BV) on cerebral noradrenaline (NA) and 5-hydroxytryptamine (5-HT) contents, and glucose metabolism in the brain were studied using stroke-prone spontaneously hypertensive (SHR-SP), stroke-resistant spontaneously hypertensive (SHR), age-matched normotensive Wistar Kyoto (WKR) and Wistar rats. In the SHR-SP which have a low level of NA in the hypothalamus, a continuous administration of BV for 1 week induced a normalization of the hypothalamic NA content. Under the same experimental conditions, a tendency toward normalization of hypothalamic NA was also observed in SHR. 5-HT contents in the cerebellum, striatum, hypothalamus, midbrain and hippocampus of SHR showed a significant increase following a single injection of BV. Similarly, 5-HT contents in the cerebellum and cerebral cortex of Wistar, WKR and SHR showed a significant increase following a continuous administration of BV for 1 week. Both in vitro and in vivo administration of BV significantly inhibited the high concentration of K+ evoked glucose consumption in cerebral cortical slices from SHR, WKR and Wistar rats, whereas glucose consumption in cerebral cortical slices from SHR determined in the absence of high concentration of K+ increased significantly following continuous in vivo administration of BV. The present results suggest that BV may be an useful drug for improving abnormal cerebral metabolisms of NA, 5-HT and glucose.

Animals↗
PubMed1979

Radioimmunoassay of methionine enkephalin and interference by brain factor of immunoreactivity and opiate receptor binding activity.

We developed a radioimmunoassay of methionine-enkephalin (met-enk) which was found to be highly specific to the peptide and 1 pmol was the detection limit. Interference by the following peptides was practically negligible; leucine-enkephalin, LAP- or CNBr-treated met-end, alpha- and beta-endorphins. Morphine and its congeners were totally inert. Measurement of met-enk in rat brain P2 fraction revealed besides met-enk, the presence of the factor which cross-reacted with the antiserum and also appeared to bind with the brain opiate receptor. Though the nature of the factor has not yet been characterized, it is suggested that for qualitative assessment of the tissue level of met-enk, a method to selectively inactivate either the peptide or the factor should be developed first.

Animals↗
PubMedDate not supplied

Detection of GST1 gene deletion by the polymerase chain reaction and its possible correlation with stomach cancer in Japanese.

A homozygous gene deletion at the GST1 locus of genomic DNA isolated from peripheral blood was investigated for its relationship with several types of cancer using the polymerase chain reaction (PCR) technique. DNA samples were prepared from blood obtained from 128 healthy blood donors and 150 patients with cancer or chronic hepatitis. PCR primers were prepared based on the human cDNA sequence and the intron/exon sequences of the rat Yb2 gene. The amplified sequence between exons 5 and 6 including intron 5 showed very clearly the presence of absence of the GST1 gene, after electrophoresis in a 2% agarose gel. Segregation of the presence and absence of PCR product from samples of twins and their parents indicated that presence involves homozygous or heterozygous normal GST1 genotypes while absence involves only homozygous gene deletion. The patients with stomach cancer had a significantly higher frequency of gene deletion than did the healthy controls (P < 0.005). Thus, GST1 deletion may be a possible genetic marker for early detection of a group at high risk of stomach cancer.

Asian People↗
PubMedDate not supplied

Mechanism of action of beta-bungarotoxin, a presynaptically acting phospholipase A2 neurotoxin: its effect on protein phosphorylation in rat brain synaptosomes.

The snake venom phospholipase A2 neurotoxin, beta-bungarotoxin, acts presynaptically to alter acetylcholine release in both the peripheral and central nervous systems. In investigating the mechanism of this action, we found that beta-bungarotoxin inhibited phosphorylation of synapsin I, GAP-43 and MARCKS in rat brain synaptosomes. This inhibition was not due to the inhibition of ATP synthesis, action of arachidonic acid metabolites, or stimulation of phosphatase activities. Furthermore, the activities of Ca2+/calmodulin-kinase II, cAMP-kinase and protein kinase C were not altered by beta-bungarotoxin in either synaptic plasma membranes or cytosol. When synaptic plasma membranes were treated with beta-bungarotoxin, MARCKS phosphorylation was inhibited, and this inhibition was overcome by the addition of exogenous protein kinase C. These results suggest that the interaction between MARCKS and endogenous protein kinase C is altered by beta-bungarotoxin. In contrast, Naja naja atra phospholipase A2, a typical phospholipase A2 enzyme, had effects on phosphorylation which were different from those of beta-bungarotoxin: (1) inhibition of phosphorylation of synapsin I in intact synaptosomes was less potent than that by beta-bungarotoxin; (2) it stimulated basal phosphorylation of GAP-43 and MARCKS; and (3) it increased the activity of protein kinase C. The inhibition of synapsin I phosphorylation by N. n. atra phospholipase A2 in intact synaptosomes may be due to the inhibition of ATP synthesis. The stimulation of GAP-43 and MARCKS by N. n. atra phospholipase A2 can be explained by the production of arachidonic acid, which stimulated protein kinase C activity to a similar extent as that caused by N. n. atra phospholipase A2. Thus, the mechanism of action of beta-bungarotoxin appears to be quite different from that of a phospholipase A2 enzyme, suggesting that phospholipase A2 activity of beta-bungarotoxin may not be essential for its action. beta-Bungarotoxin may be a useful tool to study the physiological role of phosphorylation of synaptosomal proteins in neurotransmitter release.

Animals↗
PubMedDate not supplied

Opiate receptor characteristics in brains from young, mature and aged mice.

Age-related differences in opiate receptors were determined using young (1 month old), mature (3 and 8 months old) and aged (20 months old) mice. 3H-Dihydromorphine binding to mu-receptors in brain synaptic membranes consisted of two components: one with high affinity and one with low affinity. High affinity mu binding sites in membranes from young and aged mice had significantly less receptor densities and higher affinities than the mature mice. In the membranes from aged mouse brain, the affinity of low affinity binding sites for 3H-dihydromorphine was also significantly increased when compared to those in membranes from the 8-month-old group. Membranes from the young and aged groups revealed significantly higher affinity for binding of the kappa ligand, 3H-(-)ethylketocylazocine, than mature mice, which was not accompanied by any change in the density of the receptors. There was no change in either the number or affinity of the binding sites for 3H-(D-Ser2-Leu5)-enkephalinyl-Thr, the delta receptor ligand, among young mature and aged groups.

Aging↗
PubMedDate not supplied

Determination of sodium azide in beverages by ion chromatography.

A convenient method for determination of sodium azide in beverages using ion chromatography is described. This method combines the specificity for azide with a simple sample preparation using a bubble and trap apparatus that removes any interferences. Sodium azide in a sample was acidified, and the azide was converted to the volatile hydrazoic acid, which was trapped in 2.5 mM sodium hydroxide solution. Determination was performed by isocratic ion chromatography using suppressed conductivity detection. Calibration curves were linear for 0.5 to 20 microg/mL sodium azide and the detection limit was 0.05 microg/mL. Recoveries of sodium azide from spiked samples (10.0 microg/g) were more than 82.6%. The method was then used to analyze various beverages.

Beverages↗
PubMedDate not supplied

Expression of growth factors and their receptors in human early colorectal carcinomas: immunohistochemical study.

Human colorectal carcinomas have been demonstrated to express a variety of growth factors and their cognate receptors, forming multi-autocrine, juxtacrine and/or paracrine loops. Little information, however, is available on their expression in early colorectal carcinomas in which two genetic pathways exist, i.e. adenoma-carcinoma sequence and de novo carcinoma. This study was conducted in a total of 68 early colorectal carcinomas invading the submucosa, which were subdivided into two categories by the presence of adenomatous components, namely (a) 38 carcinomas with an adenomatous component and (b) 30 carcinoma without an adenomatous component. The tumous were also classified as polypoid, flat elevated and flat depressed type. Formalin-fixed, paraffinembedded specimens were immunostained for epidermal growth factor (EGF), transforming growth factor alpha(TGFalpha), cripto, EGF-receptor(EGFR) and c-ERBB2 gene product. Of the 68 early colorectal carcinomas, EGF, TGF-alpha, cripto, EGFR and c-ERBB2 products were detected at various degrees 24(35%), 50(74%), 31(46%), 11(16%), and 34(50%), respectively. The expression was compared between 35 polypoid carcinomas with an adenoma component (suitable for adenoma-carcinoma sequence), 14 flat carcinomas without an adenoma component (possible de novo carcinomas). A significantly higher incidence (P < 0.05) of expression of the following was noted; TGF-alpha in the polypoid carcinomas with an adenoma component, and EGF and c-ERBB2 gene product in the carcinomas without an adenoma component. There was no significant difference in the incidence of cripto and EGFR, implying common events between two categories. These results indicate that two pathways exist in tumourigenesis, in which the growth factors and their receptors are expressed in different manners. TGF-alpha might play a crucial role in carcinomas arising from adenoma, while EGF and c-ERBB2 gene products are strongly indicative of de novo carcinomas.

Adenoma↗