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Biomedical subjects

K Fukiyama

Publications and source records attributed to K Fukiyama.

At least 145 records · Page 8Linked to original sources
PubMed1980

Influence of unilateral adrenalectomy on renin-angiotensin-aldosterone system in primary aldosteronism.

In a study of 14 patients (11 Japanese and 3 white North Americans) with aldosterone-producing tumor carried out within 2 to 4 weeks after unilateral adrenalectomy, both plasma renin activity (PRA) and plasma aldosterone concentration (PAC) increased almost normally with short-term sodium depletion and upright posture. Aldosterone excretion rate (AER) also increased significantly with sodium depletion, and was normally suppressed by sodium loading. Highly significant correlations were observed between PRA and PAC (r=0.89, p < 0.001) or AER (r=0.88, p < 0.001) ater operation, whereas there had been no such correlation before operation. Either physiological or laboratory findings were normalized or markedly improved in all cases although pathohistological diagnosis was made as adenomatous hyperplasia in 10 out of 11. These results indicate that within 4 weeks of operation PRA and the remaining adrenal gland can almost normally respond to stimuli such as sodium depletion and upright posture regardless of the amount of spironolactone given preoperatively.

Adrenal Gland Neoplasms↗
PubMed1979

Individual renin-aldosterone responses of clinically healthy young Japanese men to dietary sodium and posture.

Responses to the changes in dietary sodium and posture were investigated in 9 young clinically healthy Japanese males who customarily consumed a larger amount of salt than North Americans or Europeans of mixed white ethnic background. Plasma renin activity (PRA), plasma aldosterone concentration (PAC), and urinary aldosterone excretion rate (AER) differed at each end of 3- to 4-day spans on a "control", a high-salt and a low-salt diet and of furosemide administration. PRA and PAC, also determined during the upright position following the supine blood sampling, increased after only 1 hour of standing in each condition (p less than 0.05 or more). PRA and PAC were well correlated in all 4 conditions, regardless of the posture (r = 0.806, p less than 0.001). There were also highly significant correlations between the "supine" PRA or PAC and the preceding 24-hour AER (r = 0.869, p less than 0.001) for PRA; r = 0.855, p less than 0.001 for PAC). Correlation coefficients between PRA and PAC in 9 individual subjects ranged from 0.823 to 0.987. The estimates of constant and slope of the regression line between PRA and PAC varied from subject to subject. The renin-aldosterone axis in response to changes in dietary sodium and posture must be individually assessed.

17-Hydroxycorticosteroids↗
PubMed1978

Brain metabolism and arterial acid-base balance following bilateral carotid occlusion in normotensive and experimental hypertensive rats.

The effects of bilateral common carotid artery occlusion on brain metabolism and arterial acid-base balance were studied in normotensive and experimental renovascular hypertensive rats. One hour after carotid occlusion in hypertensive rats, supratentorial lactate increased to 383% and lactate-pyruvate ratio to 280% of the controls, while adenosine triphosphate (ATP) decreased to 69%. These metabolic changes were thought to be due to cerebral ischemia. Arterial pCO2 was lowered and the pH was raised in the hypertensive animals due to cerebral ischemia induced hyperventilation. In the normotensive rats, carotid occlusion had minimal effects on cerebral metabolism and arterial acid-base balance. These results suggest that hypertensive rats are more susceptible to cerebral ischemia caused by carotid occlusion than normotensive rats. Increased cerebrovascular resistance in hypertension is discussed as a causal factor in cerebral ischemia.

Acid-Base Equilibrium↗
PubMed1977

Plasma dopamine-beta-hydroxylase activity in normal young men: its responsiveness to manipulation of sodium balance and upright posture.

Plasma dopamine-beta-hydroxylase (DBH) activity was examined in nine healthy young adults. DBH activity at rest had a wide range, near 0 to 44 I.U./L. When sodium depletion was performed by dietary sodium restriction and diuretic, the activity was significantly increased. With dietary sodium loading, it was decreased. The change in DBH activity was significantly correlated with that in hematocrit. When subjects were erected, the enzyme activity was elevated in situations regardless of sodium balance. Blood pressure and pulse rate were changed by manipulation of sodium balance and postural change. However, the change in DBH activity did not correlate with them. Plasma renin activity (PRA) was determined concomitantly in the same plasma with DBH. The change in PRA had a direct correlation with that in DBH activity. Furthermore, the change in mean arterial pressure induced by infusion of angiotensin II analogue seemed to correlate with DBH activity change by sodium depletion. When the values of DBH activity in each individual were compared throughout the study, it was observed that the biggest variance in the activity of each individual was significantly correlated with the basal activity. In longitudinal study of individuals, plasma DBH activity could be a useful index for estimation of sympathetic activity.

Adult↗
PubMed1976

Perinephritis hypertension in monkeys. I. An increase of plasma renin activity associated with increased permeability of retinal vessels and angionecrosis.

The renal parenchyma of 5 crub-eating monkeys (Macaca irus) was wrapped by cellophane, and plasma renin activity, blood pressure and vascular permeability of ocular ground were measured in comparison with 5 unoperated control monkeys. The results demonstrated that increases of systolic arterial pressure, plasma renin activity, and permeability of the retinal vessels were found in 4 operated monkeys. There was no such abnormal finding in the unoperated control monkeys. Generally there was a rough parallelism among levels of plasma renin activity and systolic blood pressure, an increase of permeability of retinal vessels and fibrinoid angionecrosis and/or necrotizing angitis similar to polyarteritis nodosa.

Animals↗
PubMed1975

Brain circulation in cerebral transient ischemic attacks.

Cranial blood flow, mean cranial transit time and cranial blood volume were measured by the intravenous RISA technique in 10 patients with cerebral transient ischemic attacks (TIA) at the various time intervals from the onset of last attack. Cranial blood flow was subnormal in 5 out of 11 determinations and mean transit time trended to be prolonged in the diseased hemisphere in cases suggestive of the unilateral hemispheric lesion. A decrease in cranial blood flow was observed in TIA with lowering of heart rate below 60/min, or with atrial fibrillation, whereas no obvious correlation was present between heart rate and cranial blood flow either in 94 patients with, or with 62 patients without cerebrovascular diseases. Cardiac dysrhythmias including bradycardia, leading to reduce perfusion to the brain was discussed as a possible factor for producing TIA.

Adult↗