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Biomedical subjects

K Uchino

Publications and source records attributed to K Uchino.

At least 73 records · Page 4Linked to original sources
PubMed1988

Altered platelet alpha 2-adrenoceptors and adrenaline response in adolescents with borderline hypertension who have a family history of essential hypertension.

We studied the relationship between a family history of essential hypertension and the characteristics of platelet alpha 2-adrenoceptors in male university students. Platelet membranes were prepared by the method of U'Prichard. Tritium-rauwolscine was used for the alpha 2-adrenoceptor binding assay. The maximum number of binding sites (Bmax) of platelet alpha 2-adrenoceptors was higher in borderline hypertensives with a family history of hypertension than in normotensives without it. However, no significant difference in the Bmax was found between the normotensives without and those with a family history. Dissociation constants (Kd) were not significantly different among the three groups. The plasma concentration of adrenaline after 30 min of standing was higher in the borderline hypertensives with a family history than in the normotensives, either with or without a family history. These results suggest that alterations in the alpha 2-adrenoceptor density or affinity for antagonists of platelets may not be linked to a positive family history of essential hypertension. However, an increased alpha 2-adrenoceptor density in platelets and an enhanced adrenaline response may be involved in blood pressure elevation in borderline hypertensives with a family history of hypertension.

Adult↗
PubMed1987

Identification of an atrial natriuretic peptide specific receptor in human kidney.

A specific receptor for human atrial natriuretic peptide (h-ANP) was identified in the human kidney using the radioligand binding assay. Samples were prepared from non-malignant renal tissues obtained at nephrectomy of patients with renal carcinoma. Binding studies using [125I]hANP were performed at 0 degree C for 20 minutes and terminated by a rapid filtration technique. Scatchard plot analysis revealed [125I]hANP bound to a single class of binding site (Kd = 0.4 +/- 0.2 nM) with a density of 16 +/- 4 fmol/mg protein in the renal cortex (n = 7). The binding was rapid and maximal binding was obtained within 20 minutes after the start of incubation. Radioligand displacement was observed in a dose dependent fashion when cold hANP was entered into the reaction mixture. However, unrelated agents, such as angiotensin II or 1-epinephrine, did not affect the binding. This is the first time characterization of the hANP receptor in the human kidney has been conducted using a Scatchard plot analysis.

Atrial Natriuretic Factor↗
PubMed1986

Quantitative determination of propranolol in plasma and plasma water from normal subjects and patients with angina pectoris by high-performance liquid chromatography.

A precise and sensitive high-performance liquid chromatographic method using a column packed with porous polystyrene gel is described for the determination of propranolol in plasma and plasma water from normal subjects and patients with angina pectoris. Propranolol in the samples was extracted with an n-heptane-isoamylalcohol (98.5:1.5) mixture after addition of penbutolol used as an internal standard. The extracts were chromatographed and detected with a spectrofluorophotometer. The quantitative limit of propranolol was 1 ng using 1 ml of plasma or 0.5 ml of plasma water. The present method should be useful for monitoring propranolol concentrations in plasma and plasma water during drug therapy and for pharmacokinetic study of propranolol.

Angina Pectoris↗
PubMed1986

Effect of 5'-nucleotidase inhibitors on mouse immune system and experimental murine tumors.

Nucleoticidin and melanocidins A and B exhibited potent inhibitory activity against 5'-nucleotidases from rat liver membrane and snake venom. Nucleoticidin retarded growth of Sarcoma 180 solid tumor, and melanocidins A and B prolonged the survival period of mice bearing B16 melanoma. These inhibitors enhanced phagocytic activity, interleukin-1 production and superoxide-generating activity of murine peritoneal macrophages. The tumor necrosis factor was also induced by the inhibitors. These results suggested that 5'-nucleotidase inhibitors inhibit tumor growth by modification of the immune system.

5'-Nucleotidase↗
PubMed1986

Existence of renal alpha 1- and alpha 2-adrenoceptors in the human kidney: radioligand binding study in membranes from the human renal cortex and medulla.

We investigated alpha 1- and alpha 2-adrenoceptors by radioligand binding studies in plasma membranes from the human renal cortex and medulla using a new alpha 1-adrenoceptor antagonist, 3H-bunazosin, and an alpha 2-adrenoceptor antagonist, 3H-rauwolscine. Human kidneys were obtained post-mortem (n = 4) or at surgery for carcinoma of the kidney (n = 10). The specific binding of both radioligands was rapid, saturable, reversible and specific. Scatchard analysis of 3H-bunazosin binding showed that the renal cortex had a KD of 4.6 nmol/l and a Bmax of 34.7 fmol/mg of protein, and the medulla a KD of 2.4 nmol/l and a Bmax of 23.2 fmol/mg. The specific binding of 3H-rauwolscine had a KD of 5.6 nmol/l and Bmax of 22.4 fmol/mg of protein for the cortex and values of 5.1 and 42.0, respectively, for the medulla. Competitive inhibition studies suggested that the binding of both radioligands was to sites with alpha 1 and alpha 2 specificity, respectively. The present studies demonstrate that human renal plasma membranes from both the cortex and medulla contain binding sites with both alpha 1- and alpha 2-adrenoceptors.

Humans↗
PubMed1985

A new 5'-nucleotidase inhibitor, nucleoticidin. I. Taxonomy, fermentation, isolation and biological properties.

A new 5'-nucleotidase inhibitor named nucleoticidin was produced by Pseudomonas sp. YM-3229G. It was isolated from a fermentation broth by trichloroacetic acid extraction, ethanol precipitation and Dowex 1 and DEAE-52 column chromatography. It inhibited 5'-nucleotidase activity of snake venom and rat liver membrane. It also showed antitumor activity against solid type Sarcoma 180.

Animals↗
PubMed1985

5'-Nucleotidase inhibitory activity of nucleoticidin, melanocidin A and melanocidin B. Structure-activity relationships.

Nucleoticidin and melanocidins A and B exhibited potent inhibitory activity against 5'-nucleotidases from rat liver membrane and snake venom. These inhibitors are polysaccharides with highly branched side chains having at least disaccharide units. This conclusion was supported by the results with polysaccharides of known chemical structures. The inhibitors showed non-competitive inhibition with respect to AMP, and urea-treatment caused a marked decrease or a disappearance of the 5'-nucleotidase inhibitory activity. Therefore, it is concluded that steric factors also play an important role in their inhibitory activity.

5'-Nucleotidase↗
PubMed1985

A new 5'-nucleotidase inhibitor, nucleoticidin. II. Physico-chemical properties and structure elucidation.

A novel 5'-nucleotidase inhibitor, named nucleoticidin, was isolated from a fermentation broth of Pseudomonas sp. The molecular weight was estimated by gel filtration to be over 1,000,000. Nucleoticidin is composed of D-glucose and D-mannose at a molar ratio of 1.7 to 1.0. Combined analyses using chemical and physico-chemical methods, such as gas liquid chromatography and mass fragmentography, revealed that nucleoticidin has a structural unit with mannosyl residues at the terminal of a (1----4) linked D-glucosyl main chain with beta-configuration.

Anti-Bacterial Agents↗
PubMed1985

New 5'-nucleotidase inhibitors, melanocidin A and melanocidin B. I. Taxonomy, fermentation, isolation and biological properties.

New 5'-nucleotidase inhibitors named melanocidins A and B were produced by Nocardioides sp. 1681 J. They were isolated from fermentation broth by trichloracetic acid extraction, ethanol precipitation and CM-cellulose and DEAE-cellulose column chromatography. They inhibited 5'-nucleotidase activity from snake venom but not from rat liver membrane at 200 micrograms/ml. They also show antitumor activity against melanoma B16.

5'-Nucleotidase↗