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Biomedical subjects

Y Nimura

Publications and source records attributed to Y Nimura.

At least 433 records · Page 24Linked to original sources
PubMed1982

Evaluation of tricuspid regurgitation by pulsed Doppler and two-dimensional echocardiography.

We analyzed tricuspid regurgitation noninvasively using ultrasonic pulsed Doppler and two-dimensional echocardiography in 66 patients in whom tricuspid regurgitation was suspected from routine clinical evaluation. All of the patients also underwent right ventriculography. Ten healthy subjects served as controls. In 62 of 66 patients, the study was adequately performed. In 58 of 62 patients, pansystolic abnormal Doppler signals were detected in the right atrial cavity, and were interpreted to indicate tricuspid regurgitant flow. Two-dimensional echocardiograms in the parasternal four-chamber view demonstrated that the region in which the abnormal Doppler signals were detected was spindle-shaped and extended from the tricuspid orifice toward the right atrial posterior wall parallel to the interatrial septum. The severity of regurgitation was graded on a four-point scale, based on the distance reached by the abnormal signals from the tricuspid orifice toward the posterior wall. For comparison, the right ventriculograms were evaluated on a four-point scale similar to the Sellers classification of mitral regurgitation. The grades by the two methods matched exactly in 36 cases, differed by one level in 23 and by two levels in three. Thus, the two methods showed a good correspondence. Similar results were obtained for the grading based on the area covered by the abnormal signals. We conclude that noninvasive grading of tricuspid regurgitation by ultrasonic pulsed Doppler and two-dimensional echocardiography is practicable.

Adult↗
PubMed1982

Idiopathic mitral valve prolapse-analysis by real-time two-dimensional echocardiography.

Mitral valve prolapse is diagnosed in real-time two-dimensional echocardiograms when there are discrepancies in the coaptation zone of the anterior mitral leaflet and the posterior mitral leaflet. Out of the 100 cases of mitral valve prolapse diagnosed in this way, 65 had prolapsed anterior mitral leaflets, 28 prolapsed posterior mitral leaflets and 7 prolapses of both the anterior and posterior mitral leaflets. In addition to the cases with mitral valve prolapse 23 cases of ruptured chordae tendineae of the mitral valve, including 15 cases which had undergone surgery, were investigated. The frequent site of mitral valve prolapse was the posteromedial commissure in the anterior leaflet and the posteromedial and anterolateral commissures in the posterior leaflet. These sites coincide with those where rupture of the chordae tendineae of the mitral valve was apt to occur. An investigation of the relation between age and mitral valve prolapse showed that the number of cases of prolapsed anterior leaflet did not increase with age, but there was an age-related increase in the number of cases of prolapsed posterior leaflets. It was also found that the degree of the prolapse progressed with age. Many of the cases of ruptured chordae tendineae of the mitral valve were in their forties or fifties, and there appeared to be some relation between the progress of the prolapse and age. Mitral regurgitant murmurs were recorded on phonocardiograms, and the severer the degree, the wider the range of the prolapse. Mitral regurgitation was more likely to occur in cases of prolapsed posterior leaflets than in those with prolapsed anterior leaflets, even if the degree and the range of the prolapse were mild.

Adolescent↗
PubMed1982

[Mitral regurgitation in hypertrophic cardiomyopathy: an analysis with two-dimensional ultrasonic Doppler echocardiography].

Intracardiac blood flow pattern in the left ventricle and left atrium was noninvasively studied by the ultrasonic pulsed Doppler flowmeter incorporated with a real-time, phased array two-dimensional echocardiography in 28 cases of hypertrophic cardiomyopathy. Emphasis was placed on the incidence and characteristic features of mitral regurgitation in this condition. The relationship of mitral regurgitation with an early systolic murmur was also studied. The results were as follows: 1) A mitral regurgitant signal by Doppler technique was noted in all cases of hypertrophic obstructive cardiomyopathy and in half of the cases of hypertrophic nonobstructive cardiomyopathy. 2) The Doppler signal of mitral regurgitation began immediately after the first heart sound. 3) The mitral regurgitant flow spread over the left atrium or directed toward the posterior half of the left atrium in the obstructive cases. However, it was localized in the vicinity of the mitral orifice in the nonobstructive cases. These findings were different from those in rheumatic mitral regurgitation or idiopathic mitral valve prolapse. 4) The findings on mitral regurgitation by the Doppler technique exhibited a satisfactory correspondence to those by left ventriculography. 5) The early part of the systolic murmur in hypertrophic cardiomyopathy was considered to be more closely related to mitral regurgitation than a turbulent forward flow due to outflow obstruction. Therefore, mitral regurgitation might have some contribution in causing a murmur in the latter period of systole.

Adult↗
PubMed1982

[New echocardiographic criterion in the diagnosis of mitral valve prolapse].

Currently, echocardiographic diagnosis of mitral valve prolapse is made when the mitral leaflets protrude into the left atrium crossing the mitral ring. However, there remains the possibility that some mitral valve prolapse, particularly mild one, is overlooked by the currently used criterion. In the present study, new echocardiographic criterion in the diagnosis of mitral valve prolapse is proposed. The criterion includes the systolic dislocation of the mitral leaflets at its coaptation zone. The validity of the new criterion is supported by the following facts. (1) Dislocation of the mitral leaflets at the coaptation zone was never observed in healthy subjects. (2) Real-time two-dimensional echocardiograms from eight cases with a midsystolic click and a late systolic murmur, the characteristic phonocardiographic findings of mitral valve prolapse, invariably demonstrated the dislocation of either the anterior or posterior mitral leaflet at the coaptation zone leading to the diagnosis of mitral valve prolapse. Four of five cases with a midsystolic click and a holosystolic murmur were also diagnosed echocardiographically as mitral valve prolapse based on the proposed criterion. However, two of the former cases and one of the latter cases did not demonstrate the protrusion of the mitral leaflets into the left atrium crossing the mitral ring, indicating inability to diagnose mitral valve prolapse based on the commonly adopted criterion. (3) Based on the extent and degree of dislocation of the coaptation of the mitral leaflets, mitral valve prolapse could be classified into nine grades. It was found that the incidence of mitral regurgitation proved by phonocardiography or angiocardiography is higher as the grade of prolapse becomes greater.

Echocardiography↗
PubMed1981

A fluorometric assay for total diamines in human urine using human placental diamine oxidase.

The detailed procedure for a new fluorometric assay for total diamines in human urine is described. The diamines were purified from the urine by cation-exchange chromatography and incubated with human placental diamine oxidase. Hydrogen peroxide formed in the diamine oxidase reaction was measured fluorometrically by converting homovanillic acid to a highly fluorescent compound in the presence of peroxidase. Because of its simplicity and high sensitivity, our present method seems useful for routine clinical investigation. The data obtained from normal subjects and patients suffering from various forms of cancer are also presented.

Amine Oxidase (Copper-Containing)↗
PubMed1981

A new enzymatic assay for total diamines and polyamines in urine of cancer patients.

A detailed procedure of a new photometric assay for total diamines and polyamines in human urine using soybean seedling amine oxidase (SSAO) as an enzyme reagent is described. It is based on the unique substrate specificity of SSAO that the enzyme is active toward all diamines and polyamines. The amines were purified from urine by cation-exchange chromatography and incubated with SSAO. Hydrogen peroxide formed in the oxidase reaction was measured photometrically by coupling 4-aminoantipyrine with phenol in the presence of peroxidase. For its simplicity and sensitivity, our method seems useful for routine clinical investigation. The data obtained from normal subjects and patients of various cancers are presented to validate the present method.

Amine Oxidase (Copper-Containing)↗
PubMed1981

[Visualization of the false tendon in the left ventricle with echocardiography and its clinical significance (author's transl)].

Echocardiographic features of the false tendon in th left ventricle and its clinical significance were reported. The subjects consisted of 132 consecutive patients, in whom the left ventricle was satisfactorily examined from various aspects with two-dimensional echocardiography. In general, the false tendon was detected in the long axis view of the left ventricle from the apical approach. It was detected in 61 of 132 consecutive patients with echocardiography. The incidence did not seem to be related to the kinds of underlying conditions. The false tendon was usually a string, a few millimeters in width, crossing the ventricular cavity from the vicinity of the papillary muscles to the interventricular septum. In a few patients it looked as Y-figure and net like. Sometimes, several sticks of the false tendon were detected. It was observed to be stretched in diastole and relaxed in systole. On the M-mode echocardiogram the false tendon was displayed as a linear echo moving with heart beat. The false tendon revealed near the interventricular septum, exhibited a motion so similar to that of the interventricular septum that it should be carefully differentiated from the echo of the left ventricular surface of the septum. In 2 patients of valvular heart disease, it was observed to be fluttered in diastole. Echocardiography was more useful in detecting the false tendon than left ventriculography.

Aged↗
PubMed1981

[Mechanism of the systolic anterior motion of the mitral valve and site of the intraventricular pressure gradient in hypertrophic obstructive cardiomyopathy (author's transl)].

The mechanism of the systolic anterior motion (SAM) of the mitral valve and the relationship between SAM and the intraventricular pressure gradient in hypertrophic cardiomyopathy were analyzed. The subjects were 15 cases, in which SAM was observed on the M-mode echocardiograms. Real-time two-dimensional echocardiography was performed at the time of cardiac catheterization and the measurement of left ventricular pressure was made with observing the spatial relationship between the tip of of the catheter and the surrounding intracardiac structures. There were two modes of the systolic anterior motion of the mitral valve in cases with SAM as follows: (1) The hypertrophied papillary muscle protruded into the left ventricular cavity in systole and it caused the displacement of the chordae tendineae, but also the tips of both anterior and posterior mitral leaflets were anterosuperiorly pulled up by the enlarged papillary muscles and the leaflets seemed apparently to intersect the left ventricular outflow tract (type II). These two types seem to make a continuous spectrum. Seven of the 15 cases examined exhibited type I and 8 cases exhibited type II or the intermediate condition. In the cases of type I, the pressure gradient was noted at the level of the tip of the papillary muscles. The inflow tract and the suprapapillary of the outflow tract exhibited a low pressure, while the apical cavity exhibited a high pressure. It is suggested that the enlarged papillary muscles make the ventricular cavity much more narrowly, resulting in the development of pressure gradient at their level. In the cases of type II, the pressure gradient was noted across the anterior and posterior mitral leaflets perpendicular to the outflow tract (subaortic area). The inflow tract exhibited a high pressure in contrast to that in the cases of type I. It is suggested that the anterosuperiorly pulled anterior and posterior leaflets dam up the ventricular cavity, resulting in the development of pressure gradient across them. Here, it should be emphasized that not only the anterior mitral leaflet, but also the posterior leaflet participates to yield the SAM and the intraventricular pressure gradient.

Adult↗
PubMed1981

[Echocardiographic features of the eustachian valve and its clinical significance (author's transl)].

The detailed informations and clinical significance of the Eustachian valve have not yet been elucidated. Real-time two-dimensional echocardiography has enabled one to investigate the Eustachian valve non-invasively. The valve was usually very small. The larger valve was a few cm in length and moved with heart beat. Its motion was analyzed with M-mode echocardiography. In the cases with sinus rhythm, the valve opened gradually in systole, and opened further in rapid filling phase,. followed by the rapid closing at the time of atrial contraction. In the cases of atrial fibrillation with severe tricuspid regurgitation, the valve remained at the semi-closed position throughout systole and opened in rapid filling phase. In one case of tricuspid regurgitation the valve was observed to flutter in systole. After the surgical repair of the tricuspid valve, systolic opening of the valve was noted, though atrial fibrillation persisted.

Adolescent↗
PubMed1981

[Evaluation of tricuspid regurgitation by the ultrasonic pulsed Doppler technique from a transcutaneous approach (author's transl)].

Severity of tricuspid regurgitation was assessed by using a combined system of the ultrasonic pulsed Doppler technique and two-dimensional echocardiography from a transcutaneous approach. The study group comprised 47 patients with various heart diseases, who were clinically presumed to have tricuspid regurgitation, and 10 healthy subjects. 1) Pansystolic abnormal flow signal was detected in an area from the tricuspid valve into the right atrial cavity in 43 patients including 8 patients without definitive signs of tricuspid regurgitation. Such abnormal flow had never been detected in healthy subjects and was considered to represent tricuspid regurgitant flow. Tricuspid regurgitant flow usually exhibited a wide band spectrum of velocity component indicating a disturbed flow. In 4 patients with clinical signs of severe tricuspid regurgitation, a laminar flow was detected in the right atrial cavity, which was considered to indicate a regurgitant jet in the central part of tricuspid regurgitant flow. 2) The area where tricuspid regurgitant flow was detected was interpreted as revealing the main direction and spread of tricuspid regurgitant flow. Based on this finding, severity of TR was classified into 4 grades by the assessment on the basis of the distance reached by tricuspid regurgitant flow in the right atrium. Severity of tricuspid regurgitation was also classified into 4 grades by right ventriculography. The grade of tricuspid regurgitation assessed by Doppler technique was nearly consistent with that assessed by right ventriculography. Severity of tricuspid regurgitation was also classified into 4 grades on the basis of the extent of the area where the regurgitant flow spread, and nearly the same results were obtained as those described above. 3) Thus, the combined use of Doppler flowmetry and two-dimensional echocardiography proved to be useful for detecting tricuspid regurgitant flow and assessing the severity of tricuspid regurgitation.

Doppler Effect↗
PubMed1981

[Blood flow analysis with pulsed echo Doppler cardiography in valvular pulmonary stenosis (author's transl)].

Blood flows in the main pulmonary artery, right pulmonary artery and right ventricular outflow tract were analyzed in 11 cases of valvular pulmonary stenosis and 10 healthy subjects by pulsed echo Doppler cardiography (two-dimensional) with the parasternal and suprasternal approaches. 1) The systolic flow in the right pulmonary artery was detected in 7 cases of valvular pulmonary stenosis, in which the flow of both right and main pulmonary arteries was detected in only one case. The flows seemed to be turbulent. These abnormal signals were never detected in healthy subjects and considered to be caused by the narrowing of the pulmonic orifice. 2) Abnormal flow signals were also detected in the right ventricular outflow tract in patients of pulmonary stenosis. Their features were as follows: (1) A systolic turbulent flow was detected in a case with severe hypertrophy of the wall and narrowing of the lumen of the right ventricular outflow tract. (2) A/S ratio, which is a ratio of the peak velocity in atrial contraction (A) to the peak velocity in systole (S), was larger in cases with pulmonary stenosis than in healthy subjects (p less than 0.05). It was considered that the atrial component in the right ventricular filling was augmented in pulmonary stenosis. (3) The PEP/ET (pre-ejection period/ejection time) of the right ventricle was smaller in cases with pulmonary stenosis than in healthy subjects (p less than 0.05). The ratio exhibited a reverse correlation with the pressure gradient between the right ventricle and pulmonary artery (r = 0.74, p less than 0.025). (4) Acceleration time index, a ratio of the time interval between the upstroke and the peak velocity of ejection flow to the ejection time, as a parameter indicating the time delay of the peak velocity exhibited a significant correlation with the pressure gradient between the right ventricle and pulmonary artery (r = 0.67, p less than 0.05). (5) No correspondence was revealed between the time interval of Q-peak velocity in systole and that of Q-peak intensity of the murmur during systole. It was remained to be clarified.

Adult↗