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Biomedical subjects

H Hirata

Publications and source records attributed to H Hirata.

At least 271 records · Page 15Linked to original sources
PubMed1983

alpha-Adrenergic receptor-mediated depolarization of rat neocortical astrocytes in primary culture.

The membrane potentials of rat neocortical astrocytes growing in primary cultures (mean resting potential; -79 mV at [K+]o = 4.5 mM) were depolarized by up to 30 mV by 10(-5) M norepinephrine added to the medium, or up to 11 mV by norepinephrine or phenylephrine applied by ionophoresis. This depolarization could be inhibited by the alpha-adrenergic receptor antagonist phentolamine (10(-5) M) but not by the beta-adrenergic antagonist propranolol (10(-5) M). These results suggest that the norepinephrine-evoked depolarizations seen in these cells may be mediated through an alpha-adrenergic receptor.

Animals↗
PubMed1983

Free amino acid concentrations in blood cells of two brothers with gyrate atrophy of the choroid and retina with hyperornithinaemia.

In this study we selected blood cells as accessible tissues and measured the free amino acid concentrations in erythrocytes, lymphocytes, and granulocytes of two patients with gyrate atrophy with hyperornithinaemia. We found that ornithine concentrations were elevated in blood cells, to different degrees depending on the type of cell, and that aspartic acid concentrations were low in erythrocytes. We also investigated the fluctuation of free amino acid concentrations in blood cells up to 24 h after the oral administration of ornithine. The ornithine concentration in the blood cells of the patients reached a peak 2 h after the oral administration, and remained high for at least 4 h, although after 2 h the concentration curves differed in the three types of cells.

Adult↗
PubMed1983

Labelled-calcium release from rat mandibles exposed to prostaglandins in vitro.

Bone resorptive effects of prostaglandins (PGs) in cultured mandibular bone tissue of rat fetus prelabelled with 45Ca were examined in comparison with those in radius-ulna. PGE1 (3 X 10(-6)-10(-4) M) and PGE2 (3 X 10(-8)-10(-4) M) could significantly stimulate the release of 45Ca from mandible with a peak effect at 3 X 10(-6) M. The effects of PGEs were more marked in mandible than in radius-ulna. Salmon calcitonin (SCT) inhibited the stimulating effect of PGE2. PGF 2 alpha did not cause the significant increase of 45Ca-release. Parathyroid hormone (PTH) at concentrations of 0.01-1.0 IU/ml dose-dependently stimulated 45Ca-release and the effects were greater in mandible than in radius-ulna. Dibutyryl cyclic (DBc)-AMP stimulated the release of 45Ca in mandible with a sharp peak effect at 5 X 10(-4) M. The results indicate that mandible is more susceptible to these bone resorptive agents than radius-ulna.

Alprostadil↗
PubMed1983

Inverted papilloma of ureter.

A rare case of inverted papilloma of the ureter in a sixty-eight-year-old man is presented, and the literature is reviewed.

Aged↗
PubMed1982

Eicosapolyenoic acids of serum lipids of Japanese islanders with low incidence of cardiovascular diseases.

Japanese are unique among the peoples of developed countries in having a high intake of eicosapentaenoic acid (C 20:5) from fresh fish and this may in part contribute to their low incidence of cardiovascular diseases. Mass spectroscopic analyses of eicosapolyenoic acids (C20:3, C20:4 and C20:5) were carried out on the serum of aged persons living on Kohama island in Okinawa and known to have the lowest incidence of cardiovascular diseases in Japan. All but 4 of the 77 persons examined (73.94 +/- 7.81 years old) led active fishing-farming lives. The total amount of eicosapolyenoic acids in the serum of persons on Kohama island (46.77 +/- 7.46 mg/100 ml) was higher (p less than 0.001) than that in people on mainland Japan, owing to the higher intake of fresh fish (147.7 g/day). A positive correlation (p less than 0.01) was found between serum C 20:5 concentration (6.82 +/- 2.54 mg/100 ml) and high density lipoprotein concentration (55.38 +/- 13.83 mg/100 ml). In addition, there were positive correlations (p less than 0.01) between serum C 20:3 concentration (6.58 +/- 1.61 mg/100 ml) and total cholesterol (188.60 +/- 32.30 mg/100 ml), and triglyceride and skinfold thickness. The blood pressure level (p less than 0.01), incidence of abnormal ECG (p less than 0.05), and salt intake (6.2-8.3 g/day) estimated from urinalysis, were all lower than the average figures for Japanese of similar ages. No persons examined showed Q-wave on ECG. The percentage of smokers and drinkers were similar for Kohama island and mainland Japan.

Activities of Daily Living↗
PubMed1980

A stable Na+/H+ antiporter of thermophilic bacterium PS3.

As a first step in the isolation of a stable Na+/H+ antiporter, its reaction in sonicated membrane vesicles of thermophilic bacterium PS3 has been characterized. The sonicated vesicles showed quenching of quinacrine fluorescence in either NADH oxidation or ATP hydrolysis. The quenching was reversed by the addition of Na+, Li+, Mn2+, Cd2+, and Co2+, but not of choline+ or Ca2+, regardless of their counter anions. 22Na+ was taken up into the vesicles by NADH oxidation, and the 22Na+ uptake was inhibited by the addition of an uncoupler. H+ release was observed on addition of Na+ to sonicated vesicles. The magnitude of the pH difference across the membrane induced by NADH oxidation was constant at pH 7.0 to 9.1, but the Na+/H+ antiport was affected by the pH of the medium (optimum pH-8.5). The Km's of the antiporter for Na+ and Li+ were 2.5 and 0.1 mM, respectively, but the Vmax values for the two ions were the same at pH 8.0. In the presence of Li+, no further decrease of fluorescence quenching was observed on addition of Na+ and vice versa. The Na+/H+ antiporter activity in PS3 was stable at 70 degrees C, and the optimum temperature for activity was 55-60 degrees C. In contrast to mesophilic cation/H+ antiporters, this antiporter was not inhibited by a thiol reagent.

Bacteria↗