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Biomedical subjects

M Onoe

Publications and source records attributed to M Onoe.

At least 73 records · Page 4Linked to original sources
PubMed1989

[A case report of ventricular septal defect accompanied by winded and elongated malformation of the aortic arch].

A three-year-old boy, surgically treated for a ventricular septal defect, had a winded and elongated aortic arch between the left common carotid artery and the left subclavian artery. Angiography revealed that the arch was positioned more caudalward than normally, and that it was in contact with the left pulmonary artery at a point near the central portion of the arch (i.e., near the position of the ductus arteriosus). The embryological cause of this malformation was speculated. It seemed unlikely that malformations was caused by involution, abnormal growth, etc., of the components of the great vessels in the coursed of embryonic development, but rather to have been caused by an abnormal elongation of the artery at the fourth arch and of the ventral artery between the 6th and 7th intersegmental artery, which had occurred after normal embryonic development. Under extracorporeal circulation, where blood was returned to the patient via the femoral artery, the patient underwent open heart surgery to close the ventricular septal defect. Pressure monitoring during the operation revealed no pressure loss in the winded and elongated portion of the artery; hence, the malformation seemed to cause no hemodynamic problems at present. Considering that the patient is only three years old and that the aorta will continue to grow, we have decided to refrain from any surgical treatment of the winded and alongated part of the aorta for the time being. However, the patient might develop aortic aneurysm in the future because of the relative coactation of the aorta and the insufficient mechanical strength of the winded and elongated area.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta, Thoracic↗
PubMed1989

[Re-operation for WPW syndrome due to recurrence of tachycardial attack].

A thirteen-year-old girl was admitted to our hospital because of tachycardial attack. Twelve years ago, she was diagnosed as WPW syndrome and division of accessory conduction pathway was performed at the other hospital, and it was described that the accessory pathway was located on the right lateral wall. ECG showed no delta wave nor PSVT postoperatively. But 12 years later, delta wave and PSVT reappeared. Operative treatment for recurrent tachycardial attacks was performed. Intraoperative pacing study revealed the right posterior-septal accessory pathway. It was divided and cryoablated. This paper reports an additional operation for the second accessory pathway of WPW syndrome.

Adolescent↗
PubMed1989

[Experimental study on the mechanism of serum leakage from expanded polytetrafluoroethylene (EPTFE) vascular prosthesis].

Even in recent years, the Blalock-Taussig (B-T) shunt operation has been carried out in order to increase pulmonary blood flow in patients of low pulmonary flow congenital heart disease. In such a case, a modified B-T shunt using an EPTFE vascular prosthesis would be employed in order to prevent blood flow obstruction in the upper extremity, and occasionally serum leakage from EPTFE vascular prosthesis is a complication. This has often troubled cardiovascular surgeons the world over, and we attempted to elucidate the mechanism of serum leakage and to discover how to prevent the situation from occurring. Using scanning electron microscopy, the structure of EPTFE vascular prosthesis was found to consist of an average of 0.5 micro meter polytetrafluoroethylene (PTFE) fibers arranged in parallel 5.0 micro meters from each other. The reason why serum does not usually leak from these widely spaced fibers is due to the presence of a repellent force derived from the surface tension and the contact angle between the solid surface of PTFE and the liquid. When the contact angle is over 90 degrees, the repellent force is in effect, while when it is below 90 degrees, this force is decreased. The surface tension and contact angle of physiological saline on the surface of PTFE showed values of 71.6 dyn/cm and 114.0 degrees, respectively, while demonstrating a strong repellent force. On the other hand, the surface tension of heparinized blood on the surface of the PTFE was 56.5 dyn/cm and the contact angle was 90.6 degrees. Thus, heparinized blood was assumed to act on the surface of the PTFE with a weak repellent force and for that reason had a tendency to easily leak from the EPTFE vascular prosthesis. When the surface of the PTFE was in contact with blood, blood protein was fixed to the surface of the PTFE and the contact angle of blood was thereby decreased. When the inner pressure of the vascular prosthesis was increased, the wall was stretched easily in a circumferential direction but with great difficulty in a longitudinal direction. With the PTFE stretched and released repeatedly, the expanded circumference was enlarged progressively due to the plastic character of the PTFE and because the spaces between the PTFE fibers were widened. In order to examine the relationship between the space between fibers and the critical pressure leading to serum leakage, computer simulation was carried out and the results showed a reversed linear correlation between the density of the fibers and the minimal pressures responsible for serum leakage.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

[A clinical experience of signs of compression in the neighboring organs after operation with Carpentier's method in dissecting aneurysm of the aorta].

A patient with a DeBakey IIIb type dissecting aneurysm of the aorta was treated with Carpentier's method. But after surgery the thromboexclusion procedure at the pseudo-lumen was insufficient. Fourteen months after surgery the left lung area suddenly became opaque, suggesting the possibility of impending rupture of the aneurysm. Therefore the patient underwent emergency surgery in which another permanent clamp was attached to the peripheral end of the aneurysm. After this operation, the aneurysm became reduced in size and the left lung inflated again, but an aorto-pulmonary fistula was formed 24 days later. After 6 months after second surgery, the patient began to experience dysphagia and dyspnea on exertion. Detailed examinations showed that these symptoms were caused by compression of the esophagus, bronchus and pulmonary artery by the permanent clamp. That is, this clamp, which possibly moved during organic change and size reduction of the aneurysm, seems to have compressed the adjoining organs enough to cause dysfunction. Such a compression of the neighboring organs can be regarded as one of problems originating from Carpentier's method, and shows that the procedure is not problem free yet.

Aortic Dissection↗
PubMed1988

Regional blood flow in the liver, pancreas and kidney during pulsatile and nonpulsatile perfusion under profound hypothermia.

Regional blood flow in the liver, pancreas and kidney was measured under conditions of profound hypothermia associated with total circulatory arrest, to determine whether cardiopulmonary bypass with pulsatile flow would improve the blood flow in these visceral organs in comparison with nonpulsatile flow. Using 56 adult mongrel dogs, total cardiopulmonary bypass was carried out to induce hypothermia and 40 min of total circulatory arrest was performed at 20 degrees C. After total arrest, the temperature was raised to 35 degrees C. With pulsatile flow, a decrease of the regional blood flow in the liver, pancreas and kidney was prevented during cooling, especially at 20 degrees C before total circulatory arrest. Moreover, regional renal blood flow recovered rapidly with pulsatile flow after total arrest at 20 degrees C, while after arrest with nonpulsatile flow blood flow in the kidney could not be measured in the cortex and was significantly lower in the medulla. In summary, pulsatile flow improves the hepatic, pancreatic and renal blood flow and, referring to our previous experiments, protects the function of these organs during cardiopulmonary bypass associated with profound hypothermia and total circulatory arrest.

Animals↗
PubMed1988

[Treadmill exercise echocardiography: quantitative analysis of regional left ventricular wall motion by computer graphics].

To detect significant coronary lesions based on exercise-induced reversible asynergy, two-dimensional echocardiograms were recorded before and immediately after treadmill exercise test in 15 patients with angina pectoris (AP) and six patients with neurocirculatory asthenia (NCA). Short-axis views of the left ventricle were analyzed quantitatively, using the following indices: segmental area change (%A); segmental wall thickness change (%Th); and relative curvature (rC) which was the product of curvature of each segment multiplied by end-diastolic circumference. The results were compared with those of coronary angiography, T1-201 myocardial emission computed tomography, and exercise electrocardiography. 1. The results of comparisons of quantitative analysis by %A, %Th, and rC with qualitative (visual) analysis were as follows: the sensitivities were 57%, 74% and 91%; the specificities were 75%, 75% and 90%; and the accuracies were 68%, 75% and 90%, respectively. 2. To detect coronary stenosis of more than 75%, visual assessments and assessments by rC were superior to assessments by %Th or %A. The accuracies were 93%, 91%, 73% and 61%, respectively. 3. In five cases with three-vessel disease, all diseased coronary arteries were detected by treadmill exercise echocardiography using rC as an index. However, by treadmill exercise T1-201 myocardial emission computed tomography, the diagnosis of three-vessel disease was possible in only one case. 4. The results of treadmill exercise electrocardiography were positive in 11 of 15 the AP patients and in all six NCA patients. The results of exercise echocardiography using rC as an index were normal in all NCA patients and abnormal in 14 of the 15 AP patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Image analysis of chlorophyll fluorescence transients for diagnosing the photosynthetic system of attached leaves.

A new image instrumentation system for quantitative analysis of the rapid change in intensity of chlorophyll fluorescence during dark-light transition (CFI, chlorophyll fluorescence induction), which is a sensitive indicator of the various reactions of photosynthesis, was developed and its performance was evaluated. This system made it possible to resolve CFI at any small leaf area (about 1 square millimeter) of a whole leaf when the plant was illuminated by blue-green light at more than 50 micromoles photons per square meter per second. In order to test the usefulness of this system, we applied it to analyze the effect of SO(2) on photosynthetic apparatus in attached sunflower leaves. Dynamic CFI imaging over the whole single leaf, where there was no visible injury, indicated not only the local changes in photosynthetic activity but also the site of inhibition in photosynthetic electron transport system in chloroplasts. The new instrumentation system will be useful for the analytical diagnosis of various stress-actions on plants in situ.

Journal Article↗
PubMed1986

[Quantitation of regional left ventricular wall motion by curvature: two-dimensional echocardiographic analysis].

Echocardiographically abnormal regional configuration of the left ventricle is one of the clues in detecting asynergy of the left ventricular wall. For the quantitative assessment, regional left ventricular configuration was expressed quantitatively using a new index, relative curvature. To obtain the end-systolic curvature, end-systolic echocardiograms were digitized and divided into eight segments. Then end-systolic curvature was determined as the reciprocal of the circumradius of a triangle determined by three consecutive dividing points. Relative curvature was defined as the product of end-systolic curvature multiplied by end-diastolic circumference. To assess the accuracy of quantitative analysis of regional left ventricular wall motion by relative curvature, short-axis images of the left ventricle at the level of the chordae tendineae were analyzed in 20 patients with myocardial infarction and 20 normal subjects by three different indices: segmental area change using a fixed reference system, segmental wall thickness change, and relative curvature. Groups of 10 patients with anteroseptal infarction, 10 patients with inferoposterior infarction, and 10 normal subjects could be differentiated from each other by these three indices. With the 95 per cent confidence intervals obtained from 10 other normal subjects, asynergic segments were detected objectively. By segmental area change, the sensitivity was 100 per cent and the specificity was 90 per cent on the anterior wall; the sensitivity was 90 per cent and the specificity was 95 per cent on the posterior wall. By segmental wall thickness change, the sensitivity was 70 per cent and the specificity was 75 per cent on the anterior wall; and those were 80 per cent and 90 per cent, respectively, on the posterior wall. By relative curvature, the sensitivity was 100 per cent and the specificity was 85 per cent on the anterior wall; and those were 90 per cent and 90 per cent, respectively, on the posterior wall. It was concluded that left ventricular regional contraction could be assessed quantitatively by relative curvature which quantitatively expresses regional left ventricular configuration. This index is independent of any reference systems, so it is expected to be used for quantitative analysis of regional wall motion, even though the cardiac motion within the thorax is not disregarded.

Adult↗
PubMed1985

[Three dimensional reconstruction of the human left ventricle from multiple cross-sectional echocardiograms: comparison with biplane cineventriculography using Simpson's rule].

A system for reconstructing three-dimensional images of the left ventricle from randomly-recorded multiple short-axis two-dimensional images was developed. This system consisted of a real-time phased array sector scanner, a transducer-locating arm system for registering the spatial coordinates of the images, and a digitizer-computer system for digitizing the endocardial edge to display the reconstruction image and to calculate the left ventricular volume. The clinical applicability of this system was assessed by comparing the calculated left ventricular volumes by this system (3DE) with those measured by cineventriculography (LVG) for 10 patients. For end-diastolic volumes (EDV) determined by 3DE and LVG, the linear regression equation was EDV (LVG) = 1.07 EDV (3 DE)-3.4, SEE = 19.0 ml, r = 0.959. For end-systolic volumes (ESV), it was ESV (LVG) = 1.16 ESV (3 DE)-6.0, SEE = 13.1 ml, r = 0.970, and for stroke volumes (SV), it was SV (LVG) = 0.70 SV (3 DE) + 32.3, SEE = 24.5 ml, r = 0.606. This method was considered applicable to clinical non-invasive measurements of left ventricular volumes. Digitized images were easily processed by a computer, and much informations, such as volumes, shapes and wall motion, were assessable.

Cardiac Volume↗
PubMed1984

Computer analysis of cross sectional echocardiogram for quantitative evaluation of left ventricular asynergy in myocardial infarction.

Left ventricular asynergy in myocardial infarction was assessed quantitatively by computer analysis of the cross sectional echocardiogram. Short axis cross sectional images of the left ventricle at the levels of the mitral valve, papillary muscle, and apex were recorded by a phased array sector scanner in 30 patients with healed myocardial infarction and 15 normal controls. Endocardial and epicardial short axis images of the left ventricle were transferred from video tape to a minicomputer through the interface circuits, then digitised and processed automatically by a minicomputer. Automatic edge detection of the endocardial and epicardial wall was performed by applying sequential steps including smoothing, second derivative technique, dynamic thresholding, and approximation of boundaries by a spline curve. To quantify regional wall motion, the short axis cross sectional left ventricular wall of each level was divided into eight octants with eight axes at 45 degrees angles from the initial standard axis which was constructed from the geometric centre of the end diastolic left ventricular cavity to the posterior end of the right side of the interventricular septum. Segmental hemiaxis, segmental area, segmental wall thickness, and those changes during cardiac cycle were measured and calculated in each segment automatically by a computer. Regional contractility of the left ventricle was evaluated by percentage systolic changes of the segmental hemiaxis, area, and wall thickness. These values were significantly reduced in the infarcted left ventricular wall as defined by left ventriculography and electrocardiography. Moreover, percentage hemiaxis changes obtained by quantitative left ventriculography described by Herman and colleagues correlated well with those using our analytical method of cross sectional echocardiography in the corresponding segments. The geometric centre of the left ventricular cavity determined by the computer moved slightly towards the anterior wall during systole in normal subjects, possibly reflecting the anterior swinging motion of the heart. The geometric centre of the left ventricular cavity in myocardial infarction moved towards the infarcted wall, showing that the floating reference system was inferior to the fixed reference system for the quantification of abnormal wall motion in myocardial infarction. In conclusion, a computer analysis of the short axis cross sectional echocardiogram of the left ventricle using the fixed reference system has shown its ability to evaluate left ventricular contraction abnormalities, especially systolic wall thickening, which is relatively free of arbitrary interpretation of the wall motion caused by the anterior swinging motion of the heart.

Adult↗
PubMed1984

Computerized processing of two-dimensional echocardiograms for the quantification of left ventricular regional contractility.

A new practical method of computer digital image processing of two-dimensional echocardiograms was developed for the quantification of the left ventricular regional contractility. Short axis, cross-sectional images of the left ventricle at the levels of the mitral valve, papillary muscle and apex were recorded by a phased array sector scanner. The echo data recorded on video tape were transfered to a minicomputer through the interface circuits and digitized and processed automatically. Automatic edge detection of the endocardial and epicardial walls was performed by applying sequential steps, including smoothing, dynamic thresholding, region growing and filling small holes. The rationale for edge detection depended upon the assumptions that the abrupt changes of the gray levels occurred at the boundaries and that the points with the maximum gradient values are boundaries of the left ventricular wall. Best-fit contours of endocardial and epicardial edges were drawn by fitting a spline. The short axis cross-sectional left ventricular wall at each level was divided into eight segments, with the center of gravity of enddiastolic left ventricular cavity and the axis connecting this with the posterior end of the right side of the septum being used as the reference point and line. The segmental hemiaxis, area and wall thickness were measured every 33 msec from end-diastole during the cardiac cycle and the systolic percent changes were calculated automatically by a computer. Regional contractility of the left ventricle was evaluated by systolic percent changes of the segmental hemiaxis, area and wall thickness. The measured values in a patient with dilated cardiomyopathy were lower than those of a normal subject, probably reflecting myocardial damage of the left ventricle. Although there are some points to be improved, including a better system for transferring echo data to the computer and the evaluation of the validity of this fixed reference system, it is likely that computer analysis of the short axis cross-sectional echocardiogram of the left ventricle will be useful in a clinical setting.

Cardiomyopathy, Dilated↗