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Biomedical subjects

M Yasujima

Publications and source records attributed to M Yasujima.

191 records · Page 11Linked to original sources
PubMed1975

Circulating renin in essential hypertension: an evaluation of its significance in the Japanese population.

Plasma renin activity (PRA) was measured in 139 healthy subjects and 200 patients with essential hypertension. There was an obvious relationship between the PRA levels and aging. Elevated PRA values were obtained only in younger subjects under 20 years of age, while the PRA levels were very low only in advanced ages over 60 years. In essential hypertensive subjects, subnormal resting PRA was found in 23.5 per cent, normal PRA in 64.5 per cent, and high PRA in 12 per cent. A marked impairment of renal function and severe retinal changes were observed in the patient with high resting PRA values. On the contrary, hypertensive complications of the kidney and ocular fundi were mild in the patients with low resting PRA values. A reaction of renin secretion was studied in 161 patients with essential hypertension. There were no apparent relationships between the responsiveness of the renin system to intravenous furosemide following upright posture and hypertensive vascular injury.

Adolescent↗
PubMed1975

Effects of 1-sarcosine-8-isoleucine-angiotensin II on blood pressure and plasma renin activity in various types of hypertension.

The pharmacological effects of 1-Sar-8-Ile-angiotensin II on blood pressure and plasma renin activity (PRA) were studied in 5 normal subjects and in 19 patients with hypertension of various etiologics including malignant hypertension, renovascular hypertension, essential hypertension, and primary aldosteronism. Intravenous administration of this peptide induced a significant pressor response in normal or low PRA subjects at infusion rates of 100-600 ng/kg/min. Similar pressor response was also observed in renovascular hypertensives with normal PRA who were cured later by surgical treatment. The blood pressure in high PRA group was lowered remarkably by infusion of this angiotensin II inhibitor. A significant increase in PRA was obtained in subjects with malignant hypertension following the infusion of this peptide. However, there was no detectable rise in PRA in other subjects with normal or high PRA. The present data show that circulating angiotensin II plays an important role in maintaining high blood pressure in high PRA patients, especially in malignant hypertension, while it is not directly involved in the maintenance of high blood pressure in human chronic renovascular hypertension.

Adolescent↗
PubMed1975

Renal effects of prostaglandin E1 in hypertensive patients.

The effects of prostaglandin E1 on fluid and sodium excretion, creatinine clearance and renin release were examined in 26 hypertensive patients including 9 cases of essential hypertension, 10 of renovascular hypertension and 7 of primary aldosteronism. When prostaglandin was infused intravenously in a total dose of 120 mug in 60 min, urine volume was increased in 70% of cases, and sodium excretion in 61%, but little changes were observed in creatinine clearance. The most prominent diuresis and natriuresis were obtained in primary aldosteronism (mean increase was 319% in urinary volume, and 222% in sodium output). The average increases in urinary volume were 61% in patients with essential hypertension and 97% in renovascular hypertension. And urinary output of sodium was increased by 63% in the former and 56% in the latter. The remarkable renal effects of prostaglandin E1 in primary aldosteronism were completely abolished after the administration of spironolactone. Significant elevation of plasma renin activity resulted from prostaglandin E1 infusion in essential hypertension, while no constant effect was obtained in renovascular hypertension and primary aldosteronism. The present experiments indicate that prostaglandin E1 has different effects on the kidney according to the types of hypertension and the effects correlate closely with patient's status of extracellular fluid volume or sodium balance.

Adolescent↗
PubMedDate not supplied

Periventricular hyperintensity detected by magnetic resonance imaging in infancy.

Twenty-one infants younger than 12 months of age were diagnosed as having periventricular hyperintensity (PVH) on T2-weighted magnetic resonance imaging. Ten infants had experienced neonatal asphyxia, 6 intracranial hemorrhage, 2 bacterial meningitis, and 3 apnea. PVH was classified according to its extent. Round foci of PVH surrounding the frontal and occipital horns of the lateral ventricles were observed in 4 infants (PVH pattern I). Continuous PVH was observed in 17 infants (PVH patterns II and III). Fourteen infants with continuous PVH had spastic diplegia or quadriplegia. Developmental delay was demonstrated in 15 infants with continuous PVH. No PVH pattern I infants had cerebral palsy; only 1 such infant had mild developmental delay. Our study suggests that the extent of PVH reflects the severity of brain damage in neonates with cerebral injuries.

Asphyxia Neonatorum↗
PubMedDate not supplied

Magnetic resonance imaging in preterm infants.

Magnetic resonance imaging was performed in 9 preterm infants at 37-43 weeks postmenstrual age. They all were born at 26-35 weeks gestation. Myelination was graded according to its most cephalic location. Myelination pattern 2 (myelination observed in the posterior limb of the internal capsule and adjacent structures of the thalamus and lenticular nucleus) was demonstrated in 2 infants, pattern 3 (myelination of the corona radiata) in 3 infants, and pattern 4 (myelination of the centrum semiovale) in 4 infants. Bilateral low intensity areas were found on T1-weighted images in 7 infants and a ribbon-like, high intensity was observed in 5. These findings revealed a wide variety of magnetic resonance imaging appearance in apparently normal preterm infants. Caution is needed in interpreting the pathologic nature of such features in preterm infants during the perinatal period.

Asphyxia Neonatorum↗
PubMedDate not supplied

Regulation of uterine smooth muscle bradykinin receptors by bradykinin levels and angiotensin converting enzyme inhibitor in the rat.

1. Bradykinin infusion (0.1 microgram/min i.v.) decreased the number of uterine bradykinin receptors by 20% at Day 2. Bradykinin receptors returned to control levels at Day 7. 2. Captopril infusion (1.7 micrograms/min i.v.) induced prolonged decreases in the number of uterine bradykinin receptors of 15% at Day 2 and of 13% at Day 7, respectively. 3. The number of uterine bradykinin receptors was increased in two-kidney, one clip hypertensive rats by 19%. 4. These results suggest that endogenous bradykinin participates in the regulation of uterine bradykinin receptors. 5. Decreased uterine bradykinin receptors induced by captopril might reflect increased endogenous bradykinin.

Angiotensin-Converting Enzyme Inhibitors↗
PubMedDate not supplied

Magnetic resonance imaging in infantile spasms: effects of hormonal therapy.

Magnetic resonance imaging (MRI) was performed on five patients with infantile spasms who were treated with relatively low doses of adrenocorticotrophic hormone (ACTH) to study the extent of brain shrinkage induced by ACTH therapy. MRI prior to ACTH therapy revealed periventricular hyperintensity (PVH) areas and poor myelination in four patients. In one case, MRI performed 2 days after initiation of ACTH therapy also showed PVH and poor myelination. Brain shrinkage was observed 2 weeks after initiation of ACTH therapy. The most impressive follow-up finding upon MRI was the decrease in PVH found in four patients. The differentiation between myelinated white matter and surrounding cortex became poorer in three cases. Cortical atrophy progressed in all patients but ventricular dilation progressed in only one patient. At the end of ACTH therapy, ventricular dilation progressed in all cases. These findings suggest that loss of water not only from periventricular white matter but also from cortex is the main etiological factor of brain shrinkage induced by ACTH.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Antihypertensive effect of MK-421 in rats. Role of the renal kallikrein-kinin system.

To study the hypotensive mechanism of the new oral converting-enzyme inhibitor, MK-421, we evaluated the antihypertensive effect of MK-421 in rats with hypertension induced by chronic administration of norepinephrine (NE) or vasopressin and measured urinary kallikrein and kinin excretions as indices of the renal kallikrein-kinin system. When 6 mg/kg/day of MK-421 was administered simultaneously with 1.8 mg/kg/day of NE, the systolic blood pressure of conscious rats rose on Day 1 to only 122.6 +/- 3.4 mm Hg compared with the rise to 146.3 +/- 1.6 mm Hg when NE alone was infused (p less than 0.001). Similarly, when the same dose of MK-421 was administered simultaneously with 7.2 U/kg/day of vasopressin, the systolic blood pressure of conscious rats rose on Day 1 to only 117.4 +/- 3.8 mm Hg compared with the rise to 141.6 +/- 3.4 mm Hg when vasopressin alone was infused (p less than 0.01). The antihypertensive effect of MK-421 was sustained for 6 days in rats infused with NE or vasopressin. Infusion of NE alone resulted in a small but significant increase in urinary kallikrein excretion and no change in urinary kinin excretion. The combined administration of NE with MK-421 induced additional increases in urinary kallikrein and kinin excretions. Vasopressin alone resulted in marked decreases in urinary kallikrein and kinin excretions. The combined administration of vasopressin with MK-421 induced no additional changes in urinary kallikrein and kinin excretion. These results indicate that the hypotensive effect of MK-421 may depend on a reduced sensitivity of the peripheral arteries to vasoconstrictor substances.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors↗