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Biomedical subjects

H Furuta

Publications and source records attributed to H Furuta.

At least 145 records · Page 8Linked to original sources
PubMed1990

Islet amyloid polypeptide amide causes peripheral insulin resistance in vivo in dogs.

Islet amyloid polypeptide is a 37 amino acid hormone-like peptide which is the major protein component of islet amyloid deposits commonly found in patients with Type 2 (non-insulin-dependent) diabetes mellitus. Recent studies indicate that a physiologically active form of this peptide appears to be carboxyamidated and secreted from the insulin-producing beta cell. In order to clarify the possible in vivo actions of islet amyloid polypeptide, we have studied the effects of synthesized islet amyloid polypeptide-amide on peripheral glucose utilization by performing hyperinsulinaemic euglycaemic glucose clamp studies on dogs. Exogenously administered islet amyloid polypeptide-amide (an infusion from 1.0 to 100 micrograms.kg-1.h-1, over 2 h) inhibited the insulin-stimulated glucose disposal rate in a dose dependent manner. Twenty-five micrograms.kg-1.h-1 of islet amyloid polypeptide-amide infused via a peripheral vein significantly lowered the glucose disposal rate by 20% (from 17.4 +/- 1.7 to 14.4 +/- 1.7 mg.kg-1.min-1, n = 5, p less than 0.01). These findings suggest that islet amyloid polypeptide-amide causes peripheral insulin resistance in vivo.

Amyloid↗
PubMed1990

Plasma concentration of atrial natriuretic factor in idiopathic oedema.

Low level of plasma atrial natriuretic factor (ANF) under altered dietary sodium and its elevation during bigeminy were found in a 40-year-old woman with idiopathic oedema. The natriuretic effect of this peptide and the role of renin-angiotensin-aldosterone system in oedema formation in this disorder are discussed.

Adult↗
PubMed1990

Cytolytic action of Vibrio vulnificus haemolysin on mast cells from rat peritoneal cavity.

The mode of action of Vibrio vulnificus haemolysin (VVH) on mast cells from the peritoneal cavity of the rat was examined. VVH induced histamine release, and damage to the mast cells, in a dose-dependent fashion. When 1 microgram of VVH was added to c. 10(5) mast cells at 37 degrees C, histamine release was observed after a lag period of 5-10 s, and was complete within 5 min. The action was temperature-dependent, and was not induced at 4 degrees C. Disodium cromoglycate, a membrane stabiliser for mast cells, inhibited the histamine release significantly, but the effect was not dose-dependent. Moreover, leakage of lactate dehydrogenase from VVH-treated mast cells was observed. These results suggest that VVH acts on the cell membrane of mast cells and is cytolytic.

Animals↗
PubMed1990

[Direct evidence of alpha-adrenoceptor binding in rat and human adrenal glands].

In order to determine whether or not alpha-adrenoceptors are present in adrenal glands, radioligand receptor binding assay was performed in both Sprague-Dawley (SD) rat and human adrenal gland membranes. Radioligand binding assay using 3H-prazosin as an alpha 1-adrenoceptor ligand and 3H-yohimbine as an alpha 2-adrenoceptor ligand, clearly demonstrated alpha 1 and alpha 2 receptors present in both rat and human adrenal gland membranes. Maximal binding capacity (Bmax) and dissociation constant (Kd) of 3H-prazosin binding to the rat adrenal gland were 12.5 fmol/mg protein, and 0.11 nM, respectively. Those for the membrane preparations from adrenal cortex and medulla of the normal human were 16.3 fmol/mg protein, 0.34 nM and 16.3 fmol/mg protein, 0.27 nM, respectively. And those of the human pheochromocytoma were 25.6 fmol/mg protein, 0.15 nM, respectively. On the other hand, Bmax and Kd of 3H-yohimbine binding in the rat adrenal gland to were 22.9 fmol/mg protein, and 4.28 nM, respectively. Those for the membrane preparations from adrenal cortex and medulla of the normal human were 40.4 fmol/mg protein, 5.15 nM and 12.2 fmol/mg protein, 5.39 nM, respectively. And those of the human pheochromocytoma were 35.8 fmol/mg protein, and 1.08 nM, respectively. Bmax (35.8 fmol/mg protein) of 3H-yohimbine binding in the pheochromocytoma was significantly (p less than 0.01) greater than that (12.2 fmol/mg protein) in the human normal adrenal medulla, while Kd (1.08 nM) of this binding in the human pheochromocytoma was significantly (p less than 0.01) lower than that (5.39 nM) in the human normal adrenal medulla. Our data suggest that the alpha 2 receptor had greater affinity and binding site density to its agonist in the human pheochromocytoma than in the human normal adrenal medulla.

Adrenal Gland Neoplasms↗
PubMed1990

[Study of the effects of dopamine hydrochloride on alpha 1-adrenoceptors in rat kidney].

We studied the number and affinity of catecholamine receptors in SD rat kidney by radioreceptor technique. The following conclusions were obtained: 1) By using 3H-prazosin, the numbers of alpha 1-receptor (Bmax) in rat renal cortex were greater than those in rat kidney medulla. As for affinity (Kd), the significance was not recognized between the two. Bmax of the rat renal cortex to 3H-prazosin binding was 96.1 fmol/mg protein, and Kd was 0.17 nM, and for the rat renal medullar these values were 44.5 fmol/mg protein and 0.13 nM, respectively. 2) By measurement of D1-receptor using 3H-SKF38393 in the rat renal cortex in the Scatchard plot analysis, positive cooperativity was observed under the low concentration of hot ligand which was less than 1 nM. But at the concentration of hot ligand over 1 nM, the plots showed a straight line. Bmax of the rat renal cortex to 3H-SKF38393 was 2.5 pmol/mg protein and Kd was 5.3 nM. 3) Based on displacement by dopamine for 3H-prazosin binding to rat renal cortex, it was surmised that high concentration of dopamine had an affinity to alpha 1-adrenoceptors. 4) There was no change in the Kd and Bmax of alpha 1-receptor in the rat renal cortex after incubation of samples with low concentration of dopamine. However, in the case of high concentration of dopamine, a remarkable decrease of the affinity (Kd) of alpha 1-adrenoceptor was observed.

Animals↗
PubMed1989

Effect of hyperbaric oxygen therapy on essential haematuria.

Forty-three patients with essential haematuria were studied for 35 days to determine the efficacy of hyperbaric oxygen (OHP) exposure on haemostatic ability. Out of 15 untreated patients, haematuria persisted for the study period in all but one patient (6.7%). Out of 11 patients who received 90 mg/day of carbazochrome sodium sulfate and 750 mg/day of tranexanic acid excellent haemostatic results had been obtained in 2 (18.2%). Results of exposure of 17 patients to 2 atm. pressure of OHP for 90 min daily were excellent in 10 (58.8%) and good in one (5.9%). No serious adverse effects had been noted following OHP treatment. These results indicate that OHP can be applied for the treatment of essential haematuria if routine haemostatic drugs fail to improve the condition.

Adrenochrome↗
PubMed1989

Impaired urine concentrating ability in Itai-itai (ouch-ouch) disease.

A case of Itai-itai (ouch-ouch) disease with reduced urinary kallikrein excretion and slightly enhanced renin-angiotensin-aldosterone system is described. Although it is well known that cadmium toxicity frequently affects the renal tubular lesions, this report is the first to demonstrate the impaired urine concentrating ability in this disease.

Aged↗
PubMed1989

The effect of adrenal surgery on plasma atrial natriuretic factor and sodium escape phenomenon in patients with primary aldosteronism.

Plasma concentrations of atrial natriuretic factor and some vasoactive substances were determined in 8 patients with aldosterone-producing adenoma, 10 with idiopathic adrenal hyperplasia, 10 normotensive subjects and 12 patients with essential hypertension. Plasma atrial natriuretic factor concentration in patients with aldosterone-producing adenoma was the highest among the examined groups. Adrenal surgery reduced plasma concentrations of atrial natriuretic factor and aldosterone concomitant with the elevation in urinary sodium excretion, plasma renin activity and urinary sodium-to-potassium ratio. Withdrawal of trilostane (3 beta-hydroxysteroid dehydrogenase inhibitor) in patients with idiopathic adrenal hyperplasia increased plasma concentrations of atrial natriuretic factor and aldosterone, and decreased the urinary sodium-to-potassium ratio, plasma renin activity and urinary sodium excretion. However, reduced urinary sodium excretion following trilostane treatment returned to the control level successively despite the high levels of plasma atrial natriuretic factor and aldosterone. Acute infusion of saline remarkably increased plasma atrial natriuretic factor concentration in patients with idiopathic adrenal hyperplasia and aldosterone-producing adenoma. These results suggest that a high level of atrial natriuretic factor is a characteristic feature in patients with aldosterone-producing adenoma caused chiefly by the expansion of extracellular fluid volume, and circulating atrial natriuretic factor may contribute to regulation of the sodium escape phenomenon in patients with aldosterone-producing adenoma or idiopathic adrenal hyperplasia.

Adenoma↗
PubMed1989

Age-related differences in norepinephrine and non-collagenous protein in human vas deferens.

The existence of norepinephrine or non-collagenous protein in some tissues is believed to reflect the sympathetic discharge of the structures and plays an important role in contractile ability. Specimens of vas deferens were obtained from 44 subjects in various decades of life from age 20 to 84, and levels of norepinephrine, non-collagenous protein, collagen and elastin were determined. The level of norepinephrine and non-collagenous protein declined with increasing age. Both parameters inversely correlated with age. Collagen and elastin increased with advancing age. The regression line and coefficient of correlation between both variables showed significantly positive correlations. It is suggested that the contractile ability of human vas deferens, as defined by norepinephrine and non-collagenous protein contents, decreases with age, and the age-related increase in collagen and elastin may be of importance in reducing the contractile capability of this structure.

Adult↗
PubMed1989

[Two cases of pathological dilatation of seminal duct end].

Two cases of male infertility due to pathological dilatation of seminal duct end are reported. One patient was 33 years old. He was diagnosed with azoospermia by semen analysis. The cystic wall of the seminal duct end was incised by a cold knife on the urethral scope. After the operation, 100,000-500,000/ml sperms were found in his semen. The other patient was 31 years old. He was diagnosed with severe oligoasthenozoospermia. He was operated on in a similar operation. After operation, the findings of his semen analysis improved exceedingly, and his wife became pregnant.

Adult↗
PubMed1988

Stimulation of guinea pig neutrophil superoxide anion-producing system with thymol.

Thymol stimulated O2- production in guinea pig neutrophils. O2- production occurred about 30 sec after the addition of thymol, and its rate was independent of extracellular Ca2+. Thymol-induced activity was inhibited by trifluoperazine (TFP), an inhibitor of protein kinase c, and its IC50 was less than that for 12-O-tetradecanoyl phorbol 13-acetate (TPA) induced activity. After complete activation, O2- production was reversed by addition of TFP or by washing out and resuspending in a stimuli-free medium. The responsiveness of the thymol-pulsed cells to another stimulus, TPA, was somewhat more than resting cells, but the responsiveness of the former cells to thymol was about half that of the latter cells. The ATP level of cells was reduced to one half its initial value during activation by thymol. These data suggest that the magnitude of thymol-induced O2- production in neutrophils is dependent on the initial density of the binding sites of the cells with thymol and the initial intracellular ATP concentration.

Animals↗
PubMed1988

Unilateral renal agenesis with or without ipsilateral adrenal agenesis.

We analyzed 7 patients with unilateral renal agenesis. The coexistence of unilateral renal agenesis with ipsilateral adrenal agenesis was confirmed surgically in 2 patients, 1 of whom had clinical features of Cushing's syndrome owing to adrenocortical adenoma of a solitary adrenal gland. It is imperative to suspect abnormalities of the ipsilateral adrenal gland when unilateral renal agenesis is encountered. Unilateral renal agenesis usually is asymptomatic. Recognition of this anomaly is essential for early correct diagnosis.

Adrenal Glands↗
PubMed1988

Catecholamine metabolism in pheochromocytoma and normal adrenal medullae.

The tissue contents of catecholamine, its precursor and its major metabolites were determined in 8 human pheochromocytomas and 26 normal adrenal glands. Pheochromocytomas contained significantly larger amounts of norepinephrine, dopamine, dihydroxyphenylalanine, tyrosine hydroxylase activity, metanephrine, normetanephrine and vanillylmandelic acid than did normal adrenal medullae. The content ratio of epinephrine/norepinephrine in normal adrenal medullae was significantly higher than that in pheochromocytomas but there were considerable individual variations in the metanephrine/normetanephrine and vanillylmandelic acid/3-methoxy-4-hydroxyphenylethylglycol ratios in pheochromocytomas. In normal adrenal medullae the tissue content of tyrosine hydroxylase activity correlated inversely with the tissue contents of epinephrine (r equals -0.78, p less than 0.001), norepinephrine (r equals -0.78, p less than 0.001) and total catecholamines (r equals -0.87, p less than 0.001), respectively but no significant relation was found between both parameters in pheochromocytomas. These results indicate the possible presence of a negative feedback mechanism of catecholamine via tyrosine hydroxylase in normal adrenal medullae but none in pheochromocytomas. In addition, the increased degradation catecholamine pathway in pheochromocytomas appears to be unstable compared to that in normal adrenal medullae.

Adrenal Gland Neoplasms↗
PubMed1988

Effect of high-calcium diet on urinary oxalate excretion in urinary stone formers.

The effect of mild high-calcium diet or regular-calcium diet on urinary calcium excretion, urinary oxalate excretion, urinary calcium/creatinine ratio, urinary oxalate/creatinine ratio, and the probability of being a stone former (PSF) were studied in 85 patients with idiopathic urolithiasis. Intake of high-calcium diet for 5-6 days reduced (p less than 0.01-p less than 0.001) urinary oxalate excretion, urinary oxalate/creatine ratio and PSF in patients with idiopathic hypercalciuria. Under the regular-calcium diet, administration of 60 mg/day of pyridoxal phosphate for 3 months lowered (p less than 0.05-p less than 0.01) urinary oxalate excretion, urinary oxalate/creatinine ratio and PSF in patients with idiopathic hypercalciuria alone. From these findings, intake of mild high-calcium diet appears to be beneficial to decrease the urinary oxalate excretion and PSF in patients with idiopathic hypercalciuria. Pyridoxal phosphate has all the features of suppressing such risk factors for stone formation in patients with idiopathic hypercalciuria.

Adult↗
PubMed1988

Hyperplasia of juxtaglomerular cells and renomedullary interstitial cells after renal arterial embolization in patients with renal cell carcinoma.

Renal tissue was obtained from 36 patients with renal cell carcinoma, some of whom received renal arterial embolization. The removed specimens was examined histopathologically and the concentration of some vasoactive substances in these patients was measured. Nephrectomy alone produced no discernible changes in blood pressure, vasoactive substances determined or histopathological findings of the kidney. Renal arterial embolization raised the blood pressure in association with the elevation of plasma renin activity (PRA) and urinary prostaglandin (PG) E2 excretion. A linear relationship was found to exist between PRA and mean blood pressure (r = 0.70, p less than 0.001). Hyperplasia of the juxtaglomerular (JG) apparatus, and high granularity of sudan black B granules in renomedullary interstitial cells were confirmed in removed kidneys of patients who had received embolization alone. Subsequently high renin production would be anticipated to influence overproduction of renal PG E2 in acute ischemic kidney in patients with renal cell carcinoma, and hypertension following renal arterial embolization appears to be caused by the hyperplasia of the JG apparatus.

Aged↗
PubMed1988

[Renal cyst puncture under ultrasound guidance: complications of ethanol injection].

Under ultrasound guidance, we treated 25 cases of renal cyst with 99% ethanol instillation to prevent the recurrence of this disease from January 1985 to June 1987. Patients' age was from 17 to 85 years old with the average age of 63 years. Twelve cases were men, and 13 cases were women. Among the 25 cases, eleven were asymptomatic and 14 showed clinical features of lumbago, microhematuria, hypertension or proteinuria. The aspirated site was the right side in 9, left side in 14 and bilateral kidneys in 2 cases. Subsequently, cyst puncture was carried out 27 times. We encountered 12 complications following puncture. These complications were derived from the puncture itself or caused by the ethanol instillation. Flank pain caused by the injection of ethanol, nausea, causalgia or a feeling of drunkenness appeared immediately after the inoculation procedure. However, no serious complications such as pneumothorax, perirenal hematoma or infection were recognized. Some complications arose in 7 cases of 9 examples (77.8%) following more than 50 ml of ethanol injection, but the complications were observed in only 5 cases of 18 examples (22.8%) following less than 50 ml of administration. Based on these findings, ethanol injection in renal cysts appears to be useful for the treatment of this disease. In case of huge cysts when more than 50 ml of ethanol, is instilled the case should be followed up carefully after the instillation procedure.

Adolescent↗