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Biomedical subjects

K Uruno

Publications and source records attributed to K Uruno.

27 records · Page 2Linked to original sources
PubMed1992

The functional relationship between antidromically evoked field responses of the dentate gyrus and mossy fiber reorganization in temporal lobe epileptic patients.

Field recordings from the dentate granule cell layer of in vitro brain slices of temporal lobe epileptic patients were evoked by antidromic stimulation. Tissue from the same specimen was stained by the Timm-sulfide method to assess the pattern and degree of mossy fiber reorganization into the supragranular layer. A wide range of physiological responses and Timm staining patterns was present across patients. A significant correlation was observed between the abnormality of antidromic responses, reflected by multiple secondary population spikes, and the degree of Timm staining of the supragranular layer. This relationship lends support to the hypothesis that mossy fiber synapses located in the supragranular layer may have functional implications for granule cell excitability in human epileptic tissue.

Adolescent↗
PubMed1991

Both arachidonic acid and 1-oleoyl-2-acetyl glycerol in low magnesium solution induce long-term potentiation in hippocampal CA1 neurons in vitro.

The effects of phospholipase blockers on tetanus-induced long-term potentiation (LTP) and of diacylglycerol (DG) and arachidonic acid (AA) on synaptic transmission were studied in CA1 neurons of guinea pig hippocampal slices to evaluate the role of protein kinase C (PKC) and AA on the maintenance of LTP. Tetanus-induced LTP was suppressed by perfusion with neomycin (1 mM) or 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate (NCDC, 0.1 mM), blockers of phospholipase. 1-Oleoyl-2-acetyl-glycerol (OAG, 100 micrograms/ml) and AA (100 microM) produced a temporal increase in both the amplitude of the population spike (PS) and the slope of the field excitatory postsynaptic potentials (EPSPs) but failed to produce LTP. Application of OAG or AA in low-Mg2+ (0.1 mM) solution induced LTP. OAG- and AA-induced LTP was blocked by DL-2-amino-phosphopentanoic acid (AP5; 50 microM). The administration of a potent activator of PKC, phorbol-12,13-dibutyrate (PDBu), in low-Mg2+ (0.1 mM) solution enhanced the PS and EPSPs for 2 or 3 h but this enhancement did not persist. These results suggest that PKC activation is not as important as AA for the maintenance of LTP and that OAG and AA play important roles in the maintenance of LTP in synergy with the influx of Ca2+ through NMDA receptor-coupled channels.

Animals↗
PubMed1990

The role of quisqualate receptors in the induction of hippocampal long-term potentiation.

Long-term potentiation (LTP) is the persistent facilitation of synaptic responses induced by a brief tetanic stimulation (tetanus). From our observations and the findings of others, we hereby propose a novel hypothesis of the cellular mechanisms involved in the induction of hippocampal LTP. Quisqualate receptors are first activated during tetany and this stimulates the turnover of phosphatidyl inositol (Pl). The increased turnover activates protein kinase C and this results in the induction of LTP. The influx of Ca++ through N-methyl-D-aspartate-linked receptor mechanisms may participate in this process but is not the main factor for the activation of protein kinase C. With this hypothesis, the role of quisqualate receptors associated with the turnover of Pl is emphasized, and its relevance is discussed to the input specificity of LTP and to the modulation of LTP by certain drugs.

Animals↗
PubMed1978

Vitamin E and lipoprotein levels in the sera of pregnant women.

The serum levels of vitamin E, cholesterol and lipoproteins, alpha1-lipoproteins and beta-lipoproteins in pregnant women were investigated. It was found that serum vitamin E, cholesterol and the lipoproteins had a tendency to increase throughout gestation. The mean serum alpha1-lipoprotein concentration was higher in pregnant women than in healthy control women. The ratios of the vitamin E concentration to the sum of alpha1-lipoproteins and beta-lipoproteins concentration in sera was constant. Furthermore, it was found that serum vitamin E was correlated closely to the lipoprotein content (r = 0.814, p less than 0.001), except in a few subjects with abnormally high vitamin E levels.

Cholesterol↗
PubMed1977

Vitamin E binding proteins in human serum.

The distribution of vitamin E in human serum lipoprotein fraction was investigated by measuring the amount of vitamin E in various protein fractions prepared by ultracentrifugation, gel filtration and electrophoresis. The larger part of the total serum vitamin E (up to 44%) was present in the alpha1-lipoproteins, while the beta-lipoproteins contained smaller concentrations (up to 26%).

Carrier Proteins↗
PubMed1976

Relationship between serum vitamin E levels and serum cholesterol in normal adults in rural regions of Yamagata Prefecture, Japan.

Serum vitamin E and cholesterol levels were determined for the residents in rural regions of Yamagata Prefecture, Japan. The average serum vitamin E were 0.99 +/- 0.25 mg/100ml in 166 men, and 1.06 +/- 0.26 mg/100ml in 178 women. Only 0.6% of the subjects were below 0.5 mg/100 ml. There was a significant difference between the serum vitamin E levels of men and women. However there were no statistically significant differences among serum vitamin E of various age groups. The best correlation for serum vitamin E was found with serum cholesterol.

Adolescent↗