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Biomedical subjects

K Nishimura

Publications and source records attributed to K Nishimura.

At least 919 records · Page 51Linked to original sources
PubMed1987

Moyamoya disease: MR imaging.

Eleven patients with moyamoya disease were studied with magnetic resonance (MR) imaging performed with a high-field-strength (1.5-T) superconducting magnet. In all cases a fundamental pathologic change of moyamoya disease--occlusion or stenosis of the terminal portion of the internal carotid artery and the proximal portion of anterior and middle cerebral arteries--was clearly demonstrated. The characteristic collateral network from the suprasellar cistern to the basal ganglia, which corresponds to the "moyamoya vessels" on angiograms, was seen in several patients. Various ischemic changes, including infarction, brain atrophy, and ventricular dilatation, were also well demonstrated. MR imaging plays an important role in the diagnosis of moyamoya disease.

Adolescent↗
PubMed1987

Thyroid gland: MR imaging.

Magnetic resonance (MR) imaging was performed in eight healthy volunteers and 30 patients with histologically and endocrinologically proved thyroid diseases. The use of a surface coil greatly improved spatial resolution, and normal anatomic structures were well demonstrated. In thyroid tumors, the margin, pseudocapsule, and lymph nodes were easily detected. Smooth margins, lobulated margins, and pseudocapsules were found in both adenoma and papillary carcinoma, whereas unclear margins were found only in papillary carcinoma. An unclear margin between the tumor and adjacent normal thyroid tissue seemed to reflect an ill-defined tumor border on gross pathologic examination. Metastatic lymph nodes as small as 3 mm were seen. Identification of small vessels enabled detection of dilated vessels in thyroid parenchyma in patients with Graves disease. Hemorrhage (hemorrhagic degeneration) was often found in adenoma, papillary carcinoma, and adenomatous goiter, resulting in variable signal intensity.

Adenoma↗
PubMed1987

Transection of the pituitary stalk: development of an ectopic posterior lobe assessed with MR imaging.

Magnetic resonance (MR) imaging was performed in ten patients with pituitary stalk transection who had idiopathic pituitary dwarfism. Contiguous sagittal T1-weighted images were obtained in all cases, and, in some, axial or coronal images were taken for further evaluation. On MR images, normal anterior and posterior lobes of the pituitary gland can be clearly differentiated because the posterior lobe has a characteristic high intensity on T1-weighted images. In the ten patients, the high-intensity posterior lobe was not seen, but a similar high signal intensity was observed at the proximal stump in seven patients. This high-intensity area is the newly formed ectopic posterior lobe, which secretes antidiuretic hormone just as the posterior lobe would. When the ectopic lobe completely compensates for the impaired posterior lobe, endocrinologic data indicate normal posterior lobe function. However, MR imaging can reveal the transection of the pituitary stalk and formation of the ectopic lobe.

Adolescent↗
PubMed1987

Spontaneous regression of pulmonary metastasis from renal pelvic cancer.

A case of spontaneous regression of multiple pulmonary metastases of transitional cell carcinoma is reported. Spontaneous regression of metastatic pulmonary lesions seldom occurs in transitional cell cancer, and only 3 such cases have been reported in the literature. A 42-year-old male with multiple pulmonary metastases which had regressed spontaneously for a significant period of time is herein reported. The lesions were shown to be transitional cell carcinoma, originating from the left renal pelvis. The serial immunological examinations suggest that the phenomenon might be attributed to the augmented immune response of the patient.

Adult↗
PubMed1987

Clinical application of atrial natriuretic polypeptide in patients with congestive heart failure: beneficial effects on left ventricular function.

Synthetic alpha-human atrial natriuretic polypeptide was infused in patients with congestive heart failure (CHF) (New York Heart Association class III or IV) and in those without CHF. The infusion of atrial natriuretic polypeptide (ANP) at a rate of 0.1 microgram/kg/min significantly decreased pulmonary capillary wedge pressure and increased stroke volume index in all of the patients with CHF, whereas it decreased pulmonary capillary wedge pressure but caused no significant change in stroke volume index in the patients without CHF. Concomitant significant reductions in total systemic resistance were observed in both groups of patients. The ANP infusion significantly increased the urine volume, the excretion of sodium, and endogenous creatinine clearance in the patients without CHF. In the patients with CHF, it also showed a tendency to increase all these variables, but the urine volume did not correlate with the reduction in pulmonary capillary wedge pressure. The ANP infusion also decreased plasma aldosterone concentrations in these patients, although no significant difference was observed in the decrement of the plasma aldosterone concentration in the patients with and those without CHF. These findings indicate that the ANP infusion improves left ventricular function in patients with CHF, and suggest that this improvement results mainly from the vasodilating activity of ANP.

Adult↗
PubMed1987

Hypotensive effect of SA446, an angiotensin converting enzyme inhibitor, in 2-kidney, 1-clip renal hypertensive and normotensive dogs.

Hypotensive effects of SA446, an angiotensin converting enzyme (ACE) inhibitor, and effects on the renin-angiotensin system were evaluated in conscious normotensive and 2-kidney, 1-clip renal hypertensive dogs. SA446 (1 mg/kg, p.o.) remarkably inhibited the pressor response to angiotensin (Ang) I between 1 and 6 hr after the administration in normotensive dogs. SA446 significantly decreased blood pressure at 10 mg/kg, p.o., in normotensive dogs. During repeated administration of SA446 (100 mg/kg/day, p.o.) for 13 weeks, the blood pressure was lowered, and the pressor response to Ang I and plasma ACE activity were strongly inhibited. ACE activities in the aorta and kidney were also inhibited. Plasma renin activity and plasma Ang I concentration increased by repeated SA446 application, while plasma aldosterone concentration decreased. The hypotensive effect of SA446 (5 mg/kg, p.o.) was more potent in 2-kidney, 1-clip renal hypertensive dogs than in normotensive dogs. SA446 had longer inhibitory effects on the pressor response to Ang I and more potent hypotensive effects than captopril. The hypotension caused by SA446 appears to be associated mainly with an inhibition of ACE in plasma and also in the vascular wall.

3-Mercaptopropionic Acid↗
PubMed1987

Atrial natriuretic polypeptide during exercise in healthy man.

The plasma concentration of atrial natriuretic polypeptide was measured in eight healthy men during two grades of exercise performed in the supine position on a bicycle ergometer. The plasma concentration of atrial natriuretic polypeptide slightly increased during the first exercise test with 20% of the maximal oxygen uptake and it approximately doubled during the second exercise with 40% of the maximal oxygen uptake (from 15.5 +/- 5.5 (mean +/- SD) pmol/l to 31.8 +/- 10.7 pmol/l). The increase in the plasma level of atrial natriuretic polypeptide in the second exercise was significantly greater than that in the first one. The plasma norepinephrine level and plasma renin activity showed significant increases during the second exercise test. Heart rate and systolic blood pressure also increased in response to the graded exercise. The increase in the plasma concentration of atrial natriuretic polypeptide during exercise was significantly correlated with the increase in heart rate, systolic blood pressure, and the plasma norepinephrine concentration (r = 0.75, r = 0.71 and r = 0.51, respectively). These results indicate that the plasma concentration of atrial natriuretic polypeptide increases in response to the intensity of a workload, and suggest that exercise is a useful test to evaluate the releasing function of atrial natriuretic polypeptide in the heart.

Adult↗
PubMed1987

Effect of diltiazem on acute myocardial ischemia. Study of the relationship between regional myocardial blood flow and myocardial energy metabolism.

To examine the effects of diltiazem on myocardial ischemia, 200 micrograms/kg of diltiazem were injected intravenously into anesthetized open-chest mongrel dogs 10 min after coronary ligation. This was followed by a continuous infusion of diltiazem at 10 micrograms/kg/min for 50 min. Regional myocardial blood flow (MBF) was measured by the hydrogen gas clearance method. Sixty minutes after ligation, myocardial specimens were taken from the areas where MBF was measured, and the ATP and CP contents were determined by the bioluminescence method. Simultaneously, mitochondria were isolated from the ischemic and nonischemic areas, and both the respiratory control index (RCI) and the rate of oxygen consumption in state III (QO2 III) were calculated. The aortic systolic pressure and heart rate of diltiazem treated and untreated dogs were not significantly different, and diltiazem did not increase the MBF in the area with a MBF below 40 ml/min/100 g. When MBF was 10 to 30 ml/min/100 g, the ATP content in the diltiazem treated hearts was significantly higher than that in the untreated dogs, whereas the CP content was not significantly changed. Thus, diltiazem administered after ischemia preserved ATP content in the ischemic myocardium with a MBF of 10 to 30 ml/min/100 g without significantly affecting the hemodynamics or MBF. This suggests that diltiazem exerts a cardioprotective effect by acting directly on the ischemic myocardium if it has an MBF above a certain level, even when the drug is administered after the onset of ischemia.

Adenosine Triphosphate↗
PubMed1987

Direct radiographic magnification with computed radiography.

Computed radiography was combined with a 0.1-mm microfocus radiographic tube to obtain radiographic magnification of a x3 to x5. Gray-scale image processing compensated for the loss of radiographic contrast associated with the high-kilovoltage, short-exposure technique. The high-pass spatial frequency filtering capability of the computed radiography resulted in enhanced edges and increased displayed latitude. The improved image quality obtained by magnification computed radiography allowed delineation of subtle abnormalities and small anatomic structures not apparent on conventional screen-film contact or magnification radiographs.

Humans↗
PubMed1987

Angiotensin converting enzyme in sarcoidosis and in silicosis.

Angiotensin converting enzyme (ACE) activities of bronchoalveolar lavage fluid (BALF) and serum in patients with sarcoidosis and with silicosis were measured. Serum ACE was measured by enzymic assay and radioimmunoassay. There was a close relationship between ACE activity and content (r = 0.78). Serum ACE activities in patients with active sarcoidosis (37.5 +/- 11.1 nmol/min/ml, mean +/- SD) and with silicosis (25.5 +/- 9.3) were significantly elevated from the control (18.6 +/- 6.0). BALF ACE activities in the control, patients with active sarcoidosis and with silicosis were 0.23 +/- 0.19 nmol/min/ml, 0.94 +/- 0.97 and 0.38 +/- 0.05, respectively. BALF ACE in patients with active sarcoidosis and with silicosis were significantly different from the control. When BALF ACE was corrected by the cell count of alveolar macrophage (per 10(6) cells), activity was significantly different from control only in the patients with sarcoidosis. Moreover, only the alveolar macrophages in sarcoidosis were stained by immunofluorescence and immunocytochemistry using rabbit antihuman ACE antibody. Induction of ACE in alveolar macrophage might have an important role for the activity or progression of sarcoidosis.

Adult↗
PubMed1987

General pharmacological properties of the potent angiotensin converting enzyme inhibitor rentiapril.

Pharmacological properties of (2R,4R)-2-(o-hydroxyphenyl)-3-(3-mercaptopropionyl)-4- thiazolidinecarboxylic acid (rentiapril, SA 446), a potent inhibitor of angiotensin converting enzyme, were examined. SA 446 given intravenously lowered blood pressure in anesthetized rats and rabbits dose-dependently, while it had no remarkable effect in conscious rats even at a dose of 100 mg/kg orally or intravenously. SA 446 had no effect on heart rate in anesthetized rabbits up to 100 mg/kg i.v. In anesthetized dogs, SA 446 at a dose of 1 mg/kg i.v. produced decrease in blood pressure accompanied with coronary and vertebral arterial vasodilations, but gave no change in heart rate. SA 446 had no influence on respiration of anesthetized rabbits at doses up to 100 mg/kg i.v. The drug showed no effect on contractile force or beating rate of isolated guinea pig atria at concentrations up to 10(-4) mol/l, but caused vasoconstriction of isolated rabbit ear vessels at a 0.1 ml dose of 3 X 10(-2) mol/l solution or more and relaxation of isolated rat thoracic aortas at concentrations over 3 X 10(-4) mol/l. SA 446 had no influence on beta 1- or beta 2-adrenoceptors of isolated guinea pig atria and tracheas, respectively. Neither was a calcium antagonistic action observed. SA 446 did not influence the central nervous system, neuromuscular transmission, spontaneous movement or contractile response to several agonists of isolated smooth muscles, secretion of digestive glands, blood coagulation, hemolysis or blood glucose level, and it showed no muscle relaxant, antispasmodic or local anesthetic effect.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Mercaptopropionic Acid↗
PubMed1987

[Bilateral renal cell carcinoma: report of two cases].

Two cases of bilateral renal cell carcinoma are reported. The first case is of a 54-year-old male who visited our hospital on March 7, 1984 complaining of colicky pain in his left flank. Intravenous urography showed a large mass in the upper pole of the left kidney causing deformity and dislocation of the upper calyces. There were no remarkable findings in the right kidney. Abdominal CT-scan and arteriography revealed a round and hypervascular tumor with soft tissue mass density in the upper pole of both kidneys. Nephrectomy of the left and segmental resection of the upper pole of the right kidney were performed on April 11, 1984. The second case is a 47-year-old male who visited our hospital complaining of total gross hematuria. Intravenous urography showed a large soft tissue mass at the lower pole of the left kidney. Abdominal CT-scan revealed a large tumor mass associated with central necrosis in the left kidney and also a small tumor lesion at the center of the contralateral kidney. Bilateral nephrectomy was performed on December 19, 1984, and the patient was referred to hemodialysis treatment. The cut section of the nephrectomized right kidney specimen revealed multiple minor accessory tumors. Both patients have been doing well without any evidence of recurrence or metastasis.

Carcinoma, Renal Cell↗