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Biomedical subjects

Y Nimura

Publications and source records attributed to Y Nimura.

At least 289 records · Page 16Linked to original sources
PubMed1986

Primary failure of Hancock porcine bioprosthetic valves: two dimensional echocardiographic assessment.

To reveal the process of primary failure of the Hancock porcine bioprosthetic heart valve, a real-time two-dimensional echocardiography was undertaken. There were 75 cases (84 valves) with 26 in the aortic valve position, 39 in the mitral valve position, 9 in both the aortic and mitral valve positions, and 1 in the tricuspid valve position. The subjects comprised 35 males and 40 females, whose ages ranged from 18 to 65 years with a mean of 44.7 years. Valvular changes such as thickened valve cusps or abnormal valve movement were observed in 27 (32%) of the 84 valves; more specifically, in 5 (14.3%) of the 35 aortic valves and in 22 (45.8%) of the 48 mitral valves, indicating that valvular changes occurred most frequently in the mitral valve position (p less than 0.01). In the period between valve replacement surgery and the appearance of valvular changes, no significant difference was noted between aortic and mitral valve bioprostheses. The duration ranged from 14.5 to 74.5 months with a mean of 50.2 months. Valvular changes were evident in more than 50% of the valve bioprostheses implanted 6 or more years ago. In the mitral valve position, valve cusp changes appeared more frequently at the anterior cusp than at the inner and outer cusps. The frequency was 17 cases at the anterior cusp, 6 at the inner and 9 at the outer. In 7 of the 11 cases followed up after the appearance of valvular changes, an increase in the changes was recognized 7.5 to 29.5 months (a mean of 16.4 months) later.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

[Postural effects in the jugular phlebogram in patients with complete absence of the left pericardium].

To elucidate the function of the pericardium, alterations in jugular phlebograms, intracardiac pressures and cardiac volumes induced by postural changes were examined in seven patients with complete absence of the left pericardium. Ten patients with ischemic heart disease were studied as controls. Jugular phlebograms in patients with complete absence of the left pericardium showed decreased depths of the x descent and the tall v waves followed by the deep y descents (M-shaped pattern) in the supine position. These jugular abnormalities were exaggerated in the left lateral decubitus position. By contrast, the jugular phlebograms tended to return to normal, but remained abnormal in the right lateral decubitus position. Right atrial pressure curves showed similar postural effects. However, the jugular phlebograms and right atrial pressure curves in patients with ischemic heart disease were not altered by postural changes. The characteristic alterations of the jugular phlebograms are useful indicators for diagnosing complete absence of the left pericardium. The lack of a prompt decrease in pericardial pressure during ventricular ejection due to the absence of the pericardium is one of the causes of a decreased depth of the x descent in pericardial defect. However, this cannot explain the postural alteration of the jugular phlebogram. Another possible mechanism is the decreased excursion of the tricuspid ring during systole. As indicated in our previous report, there is anterior movement of the cardiac apex during systole in cases of pericardial defect, which is exaggerated in the left lateral decubitus position and decreased in the right lateral decubitus position due to the lack of normal pericardial support. This anterior swinging motion may inhibit the descent of the tricuspid ring toward the apex, resulting in a decreased depth of the x descent of the jugular phlebogram and the right atrial pressure curve and their postural alterations. The right ventricular volume as calculated from cardiac computerized tomography and the right ventricular end-diastolic pressure were not altered significantly by postural changes in the control cases. These indices increased to a greater extent in the left lateral decubitus position than in other postures in cases with pericardial defects.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1986

[Management of left and right type intrahepatic stone associated with proximal bile duct stenosis].

Fifty-seven cases of intrahepatic stone were treated in our department from 1976 to 1984. Fifteen cases out of them were left and right type intrahepatic stone associated with the proximal bile duct stenosis. Treatments and results of these 15 cases are discussed. Percutaneous Transhepatic Cholangioscopy (PTCS) was performed in 10 cases, post operative cholangioscopy (POC) in 7 cases. These cases were divided into three groups according to the treatment received. Six patients were treated only with cholangioscopic lithotomy (Group I). Six patients underwent surgical treatment after cholangioscopic lithotomy (Group II). Other 3 patients were treated with POC (Group III). Clinical course of Group I: One patient died of recurrent liver abscess 5 years after PTCS. One died of another disease. One had suffered from empyema 5 years after PTCS, but he is doing well now. Other 3 patients are doing well now. Clinical course of Group II: All patients are doing well now. Clinical course of Group III: All patients underwent treatments for residual stones after POC. Good results were obtained in group II. Surgical treatment after cholangioscopic lithotomy is the best way for these 15 cases. Adequate operative procedure should be applied after improving the patients' condition and making an accurate diagnosis of biliary tract anomalies by means of PTCS.

Adolescent↗
PubMed1986

[Reevaluation of the surgical treatment of thyroid nodules diagnosed as cancer postoperatively].

Reevaluation was carried out on the surgical treatment for clinically benign thyroid nodules. One hundred and thirty-seven patients underwent conservative resections of the thyroid because of preoperative impression of benign nodules at the First Department of Surgery, Nagoya University Hospital from 1970 to 1984. Permanent paraffin sections of the resected specimen revealed that the nodules in 4 patients were intrathyroidal cancer (3 papillary and 1 follicular) and the nodules in the other 8 patients were associated with an unsuspected small (3 approximately 15 mm) thyroid cancer. All those patients underwent either lobectomy or subtotal thyroidectomy at the initial surgery except for one patient in whom enucleation was performed. No further intervention was carried out when the definitive diagnosis was made, except for one patient in whom the enucleation was followed by lobectomy. No neck dissection was attempted in all of them. Patients have been living and well without evidence of recurrence for 3 to 11 years and one died of unrelated disease. From these results, it is recommended that lobectomy is the least requirement in treating clinically benign nodule and that, when paraffin section reveals the tumor is intrathyroidal cancer, no further surgery is justified unless there are other foci of cancer in the resected lobe.

Adenocarcinoma↗
PubMed1986

[Progressive left ventricular dilatation in a child with hypertrophic cardiomyopathy: a case report].

Clinical pictures of a patient with progression from hypertrophic cardiomyopathy to dilated cardiomyopathy features in the end stage was described. Echocardiography performed at the age of five years revealed septal hypertrophy without systolic anterior motion (SAM). At 7 years of age, it revealed ventricular septal thickness of 18 mm, left ventricular posterior wall thickness of 24 mm, and marked SAM. Echocardiography at 14 years of age revealed left ventricular dilatation (52 mm in diastole) with poor contraction. Ventricular septal thickness was 18 mm and left ventricular posterior wall thickness was 16 mm. The SAM was no longer present. At autopsy, the heart weighed 590 g, and there was moderate dilatation of the right and left ventricular cavities. Histologically, there were massive fibrosis and myocardial disarray in the right and left ventricular walls.

Cardiomyopathy, Dilated↗
PubMed1986

[Asymmetric septal hypertrophy of sporadic form with abnormal thallium perfusion and myocardial enzymes].

Asymmetric septal hypertrophy with abnormal thallium scintigram and elevated cardiac enzymes were observed in five patients and were studied with special reference to the clinical significance of their clinicopathological features. They were not familial cardiomyopathy patients. Two of the five patients (Cases 1 and 2) exhibited the clinical features characteristic of hypertrophic cardiomyopathy without abnormal thallium perfusion and serum cardiac enzyme levels. A right endomyocardial biopsy for Case 1 disclosed myocardial fibrosis in addition to hypertrophy and disarray of myocardial fibers. The left ventricular cavities of two other patients (Cases 4 and 5) tended to be dilated with signs of impaired systolic function and asymmetric septal hypertrophy. A regional area of reduced thickness was observed in the medial portion of the left ventricular posterior wall of Case 4. The remaining case (Case 3) exhibited left ventricular dilatation and reduced left ventricular systolic function, disproportionate hypertrophy, and had clinical signs of congestive heart failure. Necropsy disclosed massive fibrosis and diffuse disarray of myocardial fibers. Some patients with familial hypertrophic cardiomyopathy progress to exhibit clinical features of dilated cardiomyopathy in the terminal stages, and have massive fibrosis of the myocardium histologically. Thallium scintigraphic abnormalities and elevated serum levels of cardiac enzymes, especially the LDH1 isoenzyme, in patients with hypertrophic cardiomyopathy may be a meaningful indicator of such progression in its early stages. The five patients in the present study exhibited a variety of clinical and histological features which may comprise a spectrum of clinical conditions during the progression from hypertrophic cardiomyopathy to a condition like dilated cardiomyopathy, similar to that in familial patients. This progression and the factors promoting it should be studied further in the near future.

Adult↗
PubMed1986

[Pulsed Doppler echocardiographic estimation of pressure gradient across a ventricular septal defect: with particular reference to potential factors of error].

The clinical validity and some problems concerning pulsed Doppler echocardiography (PD) in non-invasive estimates of pressure difference (delta P) across a ventricular septal defect were studied. The maximum velocity (max V) of the left to right shunt flow in the right ventricle was converted to delta P using the simplified Bernoulli equation: delta P = 4V2. We also used the equation: delta P = 4(V2(2) - V1(2)) to estimate the delta P in cases who had left to right shunt flows of high velocity in the left ventricle. Simulatenous recordings of both left and right ventricular pressures and PD were obtained during cardiac catheterization of 11 cases. Accurate Doppler estimates of delta P only from the maximum velocity of the left to right shunt flow in the right ventricle were impossible in nine cases whose actual delta P's were large (more than 41 mmHg) and also in eight cases whose right ventricular systolic pressure was high (either equal to or higher than left ventricular systolic pressure). Besides these 17 cases, delta P estimated by PD using the simplified Bernoulli equation in 39 cases, with pansystolic left to right shunt flows in the right ventricle, correlated well with the actually measured delta P (Y = 0.99X + 2.77, r = 0.91, p less than 0.01). The difference in the maximal instantaneous pressure gradient and Doppler delta P was considered insignificant (between 0 and 7 mmHg, mean 4 mmHg). In nine cases, the left to right shunt flows of relatively high speed (0.63 approximately 2.00 m/sec, mean 1.31 m/sec) were observed also in the left ventricle, and calculated delta P using the simplified Bernoulli equation overestimated the actually measured delta P by 2 to 16 mmHg (Y = 1.52X + 4.88, r = 0.95, p less than 0.01). However, if the delta P is estimated by using the equation, delta P = 4(V2(2) - V1(2)), without ignoring the maximum speed in the left ventricle (V1), it correlates well with the actually measured delta P (Y = 1.07X + 0.76, r = 0.98, p less than 0.01). Thus, in cases with left to right shunt flows with high speeds in the left ventricle, the equation: delta P = 4(V2(2) - V1(2)) was more accurate in estimating the delta P by pulsed Doppler echocardiography.

Blood Pressure↗
PubMed1986

[Pericardial defect: roles of the pericardium on kinetoanatomic changes of the heart influenced by patients' postures].

To elucidate the physioanatomic roles of the pericardium, the alterations in gross anatomy and cardiac motion induced by posture were examined by two-dimensional echocardiography in seven patients with total absence of the left pericardium. Ten healthy subjects were served as controls. The heart was located deeper within the chest at end-diastole in patients with pericardial defect than in healthy subjects, especially in the left lateral decubitus position. With progression of systole, the cardiac apex swung anteriorly with the cardiac base as the fulcrum, and the heart approximated the normal position at end-systole. The deeper the position of the center of the cross-section of the left ventricular cavity at end-diastole, the more exaggerated the swinging motion in systole. The deep location of the heart in end-diastole is considered to result from release from pericardial support, and the systolic tonus of the cardiac muscle restores the apex to nearly normal position. The characteristic swinging motion of the heart and its alterations dependent of posture seemed the signs suggestive of total absence of the pericardium. The shape of the short-axis view of the left ventricular cavity was nearly circular throughout the cardiac cycle. Therefore, paradoxical motion of the ventricular septum observed on M-mode echocardiography in pericardial defect results from the anterior shift of the entire heart overcoming the proper motion of the interventricular septum. The left ventricular dimension become enlarged according to the postural change from the right to left lateral decubitus positions regardless of the presence or absence of the pericardium. The right ventricular cavity became enlarged in the left lateral decubitus position in patients with pericardial defect. The elevation of hydrostatic pressure due to postural change was considered excessive due to the absence of the pericardium. In the left lateral decubitus position, systolic excursions of the mitral and tricuspid rings became more prominent in healthy subjects, whereas these excursions, particularly of the tricuspid ring, were reduced in patients with pericardial defect. Depressed tricuspid ring motion was also observed in the right lateral position in cases with pericardial defects. The reduced excursion of the tricuspid, ring and the right ventricular dilatation may affect systemic venous return to the right atrium.

Adult↗
PubMed1986

[Diagnosis of bile duct and gallbladder carcinoma by percutaneous transhepatic cholangioscopy].

Recently the technique of imaging diagnosis has been developed and biliary tract carcinomas without any symptoms can be diagnosed by US, CT and cholangiography, but preoperative definitive diagnosis should be carried out by percutaneous transhepatic cholangioscopy (PTCS) or percutaneous transhepatic cholecystoscopy (PTCCS) especially in cases of minute lesions, superficial spreading type carcinomas or biliary tract carcinomas complicated with gall stones. Operative procedures, such as hepatectomy, bile duct resection and/or pancreatoduodenectomy, have to be decided before the operation according to the extent of cancer which is diagnosed by percutaneous transhepatic cholangioscopic biopsy.

Bile Duct Neoplasms↗
PubMed1986

[A resected case of pleomorphic carcinoma of pancreatic head].

A 41-year-old man was admitted to the hospital complaining of back pain and progressive jaundice. Ultrasonography, CT and hypotonic duodenography revealed a large and well-defined tumor in the head of pancreas. The tumor was hypervascular on angiography. Total pancreatectomy was performed, and the examination of the resected specimen disclosed that the tumor was 50 X 45 mm in size and extrapancreatic tumor-forming type. Histopathologically, the tumor comprized mostly bizzare mono- and multinucleated giant cells with sarcomatous growth pattern. The patient died 6 months after operation due to liver metastasis and peritoneal dissemination. The pathological feature of the pleomophic carcinoma of the pancreas is well-known, but the clinical feature is vague because the resected cases are rare. The pathological finding of the specimen of this case is typical and it is considered that the clinical findings of this case, such as well-defined and hypervascular tumor, are characteristic of the pleomorphic carcinoma of the pancreas.

Adult↗
PubMed1985

Thallium perfusion and cardiac enzyme abnormalities in patients with familial hypertrophic cardiomyopathy.

Twelve patients of five families with familial hypertrophic cardiomyopathy were examined. Within each family, the older patients showed dilation or diminished contraction of the left ventricle by echocardiography or angiocardiography more frequently than did younger patients. LDH1 fraction (lactic dehydrogenase isoenzyme) and MB-CPK (creatinine phosphokinase isoenzyme) were increased in 7 of 10 patients. Thallium-201 myocardial scintigraphy showed perfusion defect or hypoperfusion in 9 of 10 patient. Eleven cases demonstrated remarkable hypertrophy at the macroscopic level. Marked fibrosis was observed in all 5 of the 11 patients whose histologic findings were obtained. In two necropsy cases, disarray was found throughout the right and left ventricles and the pattern of fibrosis was massive. These findings were different from those of ordinary hypertrophic cardiomyopathy. It is possible that each patient with familial hypertrophic cardiomyopathy may develop more prominent thallium and enzyme abnormalities as he becomes older, regardless of whether he develops a dilated cardiomyopathy picture.

Adolescent↗
PubMed1985

Three autopsy cases of progression to left ventricular dilatation in patients with hypertrophic cardiomyopathy.

The hearts of three cases of congestive heart failure with dilated left ventricles developing in patients with symptomatic hypertrophic cardiomyopathy (HCM) were morphologically investigated. The results showed that disproportionate hypertrophy and dilatation of the left ventricles, accompanied by massive fibrosis and myocardial disarray, were present in the three patients. The mean percent area of fibrosis of the left ventricle was 34.7% and 47.4% at the upper third and lower third levels, respectively, and was much more frequently associated with disarray (84.4 +/- 12.3%). Moreover, the fibrosis was most extensive in the lateral wall of the left ventricle, followed by the posterior, anterior, and interventricular walls. The fibrosis was also diffuse regardless of the subendocardial or subepicardial region of the heart. The findings in the present study suggest that the disarray in this particular series of HCM might be responsible for the mechanism of the fibrosis leading to dilatation of the left ventricle.

Adolescent↗
PubMed1985

A sensitive fluorometric assay for serum monoamine oxidase with kynuramine as substrate.

The detailed procedure of a new sensitive fluorometric assay for human serum monoamine oxidase (MAO) with kynuramine as substrate is described. The data on its reproducibility, stability, correlation with another method, and serum MAO levels for 150 healthy subjects and 205 patients with various diseases, are presented to support the usefulness of this method. Since our method is much simpler and more sensitive than other methods conventionally used, we can recommend it for routine clinical investigation.

Heart Failure↗