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Biomedical subjects

N Akatsuka

Publications and source records attributed to N Akatsuka.

34 records · Page 2Linked to original sources
PubMed1986

Periodic fluctuation of blood pressure in a case of norepinephrine secreting extra-adrenal pheochromocytoma.

A rare case of pheochromocytoma with wide fluctuation of blood pressure at regular 7-min intervals is described. Direct blood pressure monitoring revealed periodic changes between 120/80 mmHg and 220/130 mmHg. The plasma norepinephrine concentration increased selectively in parallel with the elevation of the blood pressure. The tumor was found adjacent to the left kidney, and all abnormal data improved after its resection.

Adrenal Gland Neoplasms↗
PubMed1985

Immobile right aortic leaflet in a case of the aortitis syndrome complicated by a left coronary sinus aneurysm.

A 37-year-old housewife had the aortitis syndrome complicated by acute aortic regurgitation and severe coronary insufficiency. Her echocardiogram at the level of the aortic valve ring revealed an enlarged left aortic sinus and an oscillating membranous structure centrally in the lumen of the aorta. At emergency surgery, there was no intimal flap in the ascending aorta, but there was a 4 cm diameter aneurysm of the left aortic sinus. The leaflets of the aortic valve per se were normal. Following its surgical repair and an aortic valve replacement, prednisolone was administered, and all abnormal laboratory data were corrected. The oscillating structure in the ascending aorta was considered to be the right aortic leaflet whose reduced mobility was caused by a distorted aortic valve ring due to the aneurysm. An immobile aortic leaflet is an extremely rare echocardiographic finding worthy to be reported.

Adult↗
PubMed1984

Intravenous leiomyomatosis of the uterus with continuous extension into the pulmonary artery.

A 56-year-old woman presented with an intracardiac tumor, as shown by two-dimensional echocardiography. Surgical treatment, undertaken in two stages, revealed a tumor which arose in the uterus, passed through both ovarian veins, the inferior vena cava, the right atrium and ventricle, and the pulmonary trunk, and extended to both pulmonary arteries. The upper portion of the tumor was removed in the first surgical operation, and the remaining tumor was removed during a second operation 1 year later. Both specimens were identical in appearance, and a pathohistological diagnosis of benign leiomyoma was made.

Echocardiography↗
PubMed1983

Differential relaxing response of various arterial smooth muscles of dogs to nifedipine.

Differences in the relaxing effects of nifedipine, a so-called calcium antagonist, were studied in smooth muscle from different arteries of dogs. The common carotid artery (Car A), celiac artery (Cel A), superior mesenteric artery (SMA), renal artery (RA), femoral artery (FA), and coronary artery (Cor A) were helically cut, and their developed isometric tensions were recorded. High potassium contraction was induced in these strips, and, at the peak of developed tension, nifedipine (10(-6) M) was added. Relaxation curves induced by nifedipine were analyzed by a curve fitting method into two to three exponentials. The general form of the equation is At equal 2 or 3 sigma i = 1 A0ie-kit. The k value shows the rate of relaxation; i.e., the larger the value the faster the relaxation. The relaxation was faster in the order of RA, SMA, Cor A, Cel A, Car A, and FA. The value of (A0i/2 or 3 sigma i = 1 A0i) X 100 shows the fraction of tension in each component of the relaxation curve A0ie-kit. The fraction of tension distributed to the faster relaxation exponentials [A02e-k2t(+A03e-k3t)] in each smooth muscle was larger in the order of RA, SMA, Cor A, Car A, FA, and Cel A.

Animals↗
PubMed1977

Effects of steady-state plasma vasopressin levels on the distribution of intrarenal blood flow on electrolyte excretion.

1. In order to evaluate the effects of arginine vasopressin (AVP) on the distribution of intrarenal blood flow and on electrolyte excretion, steady-state plasma AVP levels (4-8, 19-1, 44-3, and 100-6 micro u./ml.) were produced in anaesthetized dogs, which were hydrated to minimize endogenous anti-diuretic hormone (ADH) release. 2. The urinary excretion of sodium and potassium increased without change in their filtered loads during AVP infusion. 3. Measurement by the 133xenon washout method revealed diphasic blood flow shifts, as a function of the plasma AVP level, between compartment 1 (outer cortex) and compartment 2 (inner cortex and outer medulla) without change in compartment 3 (inner medulla). 4. In a separate study, the radioactive microsphere (15 micronm) method was used with a plasma AVP levels of 19-8 micronu./ml. Blood flow (expressed as % flow/g tissue) decreased in the outer cortex and increased in the inner cortex. 5. Total renal blood flow did not change during infusion of AVP. However, the values measured by 133xenon were lower than those measured by the microsphere method. 6. There was agreement between these two independent methods that blood flow shifted from outer to inner cortex, with no change in total renal flow, at similar plasma AVP levels (19-1 and 19-8 micronu./ml.). The relationship of these intrarenal circulatory changes to the increased electrolyte excretion is discussed.

Animals↗
PubMed1977

Systolic time intervals in patients with progressive muscular dystrophy of the Duchenne type.

Systolic time intervals (STIs) were measured in 57 patients with progressive muscular dystrophy (PMD) of the Duchenne type, and were correlated with the stages of physical disability. The total electromechanical systole (Q-A2), pre-ejection period (PEP), and left ventricular ejection time (LVET) were corrected for heart rate using the linear regression equations calculated from 91 normal subjects. Each systolic time interval index (STII), i.e. corrected STI, was analyzed. In 15 ambulatory patients (Group P-1), the STIIs did not differ significantly from those in normal controls. In 37 patients who were unable to walk (Group P-2) and 5 patients who were confined to bed (Group P-3), there was a significant increase (p less than 0.001) in the PEP index (PEPI), a decrease (p less than 0.001) in the LVET index (LVETI), and an increase (p less than 0.001) in the PEP/LVET compared with those in controls. The PEPI (p less than 0.001), LVETI (p less than 0.025), and PEP/LVET (p less than 0.001) in Group P-2 differed significantly from those in Group P-1. In Group P-3, the PEPI (p less than 0.005), LVET (p less than 0.001), and PEP/LVET (p less than 0.001) were significantly changed in comparison with those in Group P-2. Remarkable myocardial histopathologic changes suggestive of dystrophy were revealed in autopsies of 3 patients who had been in the severely disabled stage and had shown impaired STIs. It is suggested that cardiac function in patients with moderate to advanced PMD of the Duchenne type is deteriorated in proportion to the disability stages, i.e. the severity of changes in the skeletal muscles.

Adolescent↗
PubMed1976

Atrial dissociation.

Atrial dissociation was recorded in a patient with malignant hypertension and microangiopathic hemolytic anemia. Digitalis intoxication was considered the cause of atrial dissociation.

Adult↗
PubMedDate not supplied

Effect of captopril on acetylcholine-induced relaxation in the presence of nitroglycerin tolerance in isolated rabbit aorta.

We investigated the effects of angiotensin converting enzyme inhibitors on acetylcholine-induced endothelium-dependent vasodilation in the presence of nitroglycerin tolerance in rings of rabbit thoracic aorta mounted in tissue baths and precontracted with 10(-6) M norepinephrine. The vasorelaxant effects of acetylcholine were measured before and after 1 h treatment with 5 x 10(-4) M nitroglycerin. The acetylcholine dose-response curve shifted to the right after the induction of nitroglycerin tolerance. Pretreatment with captopril (a sulfhydryl angiotensin converting enzyme inhibitor), but not with M-1 (a metabolite of delapril and a nonsulfhydryl angiotensin converting enzyme inhibitor) restored acetylcholine-induced relaxation. Pretreatment with N-acetylcysteine also restored reduced acetylcholine-induced relaxation. These results suggest that the sulfhydryl group plays a major role in restoration of reduced acetylcholine-induced vasodilation in the presence of nitroglycerin tolerance.

Acetylcholine↗