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Biomedical subjects

C Kawai

Publications and source records attributed to C Kawai.

At least 181 records · Page 10Linked to original sources
PubMed1990

[Transesophageal Doppler echocardiography in the diagnosis of atrial septal defect].

To assess the usefulness of transesophageal Doppler echocardiography (TEE) in diagnosing atrial septal defect (ASD), we studied eight cases with secundum type ASD, in which the diagnosis was confirmed by cardiac catheterization and surgery. In all cases, TEE provided clear images of the interatrial septum with its defect. Shunt flow through the defect was observed by color Doppler technique, and its velocity was measured using the FFT mode. In two cases, right-to-left shunt blood flow was detected. Two types of probes were used in this study, a lateral scanning probe and a longitudinal scanning probe. The scanning plane of the former was perpendicular to the axis of the probe, and that of the latter was parallel to it. The two probes facilitated the measurement of the two right-angled dimensions, with which we could calculate the defect area, assuming the defect to be an ellipse. The volume of a left-to-right shunt was obtained by multiplying the defect area by the integration of flow velocity against time. Shunt volume per cardiac cycle obtained by this method correlated well with that obtained by the Fick's method during cardiac catheterization. In six cases without a right-to-left shunt, the coefficient of correlation was 0.98, and in all eight cases it was reduced to 0.72. Thus, we concluded that TEE is useful for diagnosing and evaluating ASD.

Adolescent↗
PubMed1990

[Clinical usefulness of transesophageal Doppler echocardiography].

The usefulness of transesophageal Doppler echocardiography (TEE) was assessed in patients with various cardiovascular diseases including 15 patients with dissecting aortic aneurysm (DAA), two with thoracic aneurysm, 16 with ischemic heart disease and 14 with acquired valvular diseases. In dissecting aortic aneurysms, TEE provided clear images of the intimal flaps even in the aortic arch and descending aorta in which clear images could not be obtained by conventional external Doppler echocardiography. The entry site was detected in 11 of the 15 (73%) cases using TEE, but in only three of the 15 cases using conventional Doppler technique. In two cases of true aortic aneurysms, TEE provided clear images of the aneurysm in the descending thoracic aorta, which was discriminated precisely from DAA. In valvular disease, all four valves (aortic, pulmonary and atrio-ventricular valves) were easily observed without disturbance by any other tissues using a transesophageal approach. In addition, valve aneurysms in the posterior mitral leaflets were detected using TEE in two cases. In two cases of mitral stenosis, a thrombus was observed in the left atrial appendage. These findings were confirmed during surgery, but could not be obtained by the conventional external studies. In 16 cases, TEE was performed during aorto-coronary bypass surgery under general anesthesia. In two of these cases, left ventricular assist devices were applied after surgery. In these cases, where conventional Doppler echocardiography was not applicable, cardiac function could be monitored by TEE. Thus, TEE is useful not only in evaluating morphological function in the cardiovascular system but also in monitoring cardiac hemodynamics during and after heart surgery.

Adult↗
PubMed1990

Significance of fill-in after thallium-201 reinjection following delayed imaging: comparison with regional wall motion and angiographic findings.

To identify reversible defects, reinjection of a small amount of thallium-201 (201Tl) following 3-hr delayed imaging was performed in 60 patients with coronary artery disease who had perfusion abnormalities on their post-exercise 201Tl images. Thallium-201 uptake was visually scored and judged as normal (Group 1), reversible defect (Group II), new fill-in after reinjection (Group IIIa) and no fill-in even after reinjection (Group IIIb). New fill-in after reinjection was observed in 27 segments of the 85 segments (32%), showing persistent defect on the stress and delayed images. The wall motion in Group IIIa was worse than Group II but better than Group IIIb. Group IIIa showed Q-wave on ECG more often (69%) than Group II (27%) (p less than 0.01), but less often than Group IIIb (85%) (p less than 0.05). These data indicate that the reinjection 201Tl imaging often identifies new fill-in in the areas of no redistribution on the delayed images and it may hold promise for assessing tissue viability which the conventional imaging may underestimate.

Adult↗
PubMed1990

[Pathophysiological analysis of cardiac function by computer processing of echocardiograms].

Automatic image processing system has been developed for analysis of cardiac function with echocardiograms. Echograms of apical long axis view were transferred to microcomputer system and processed to display three dimensional images of left ventricular myocardium. With this technology, analysis of left ventricular wall thickness in three dimensional manner revealed pathophysiological changes in ischemic heart disease.

Coronary Disease↗
PubMed1990

[Indium-111 antimyosin monoclonal antibody uptake in patients with cardiomyopathy and myocarditis].

Prognostic significance of myocardial uptake of indium-111 antimyosin antibody was evaluated in 17 patients with idiopathic cardiomyopathy; 10 patients with dilated cardiomyopathy and 7 patients with hypertrophic cardiomyopathy. Seven of 10 patients with dilated cardiomyopathy showed positive images. Three of these 7 patients with strongly positive scans died after scintigraphic examination. Six of 7 patients with hypertrophic cardiomyopathy showed positive images. Three of the patients with dilated left ventricle had prominent positive scans and higher heart to lung ratio. The heart to lung ratio of antimyosin uptake in total patients was correlated with left ventricular end-diastolic dimension and ejection fraction measured by echocardiography. In patients with myocarditis, all three patients showed positive scintigrams within 4 weeks after the onset of the disease and 1 of 6 patients was positive thereafter, who had dilated ventricle and decreased cardiac function. Thus, indium-111 antimyosin antibody imaging may be useful to evaluate prognosis of patients with cardiomyopathy and myocarditis.

Adult↗
PubMed1990

[111In-antimyosin Fab scintigraphy in cardiovascular diseases: (multicenter clinical trial)].

In a multicenter study, a total of 380 patients with myocardial infarction, myocarditis and cardiomyopathy underwent 111In-Antimyosin Fab myocardial imaging. 111In-Antimyosin Fab was administered intravenously and myocardial images were obtained 48 hours later. Only 3 patients developed mild adverse effects. Human antimouse antibodies were detected in 7 patients. Positive scans in patients with myocardial infarction were seen in 92/119 (77%) within 2 weeks after the onset of myocardial infarction, in 58/71 (82%) at 3-4 weeks, in 20/22 (91%) at 4-8 weeks and 17/31 (55%) thereafter. The location of myocardial damage delineated by 111In-Antimyosin Fab imaging was concordant with the infarct location by ECG and coronary angiography. In patients with myocarditis, 111In-Antimyosin Fab uptake was positive in 7/12 (58%) within 8 weeks and 6/17 (35%) thereafter. Positive 111In-Antimyosin Fab scans were seen in 12/36 (33%) in dilated cardiomyopathy and in 17/19 (89%) in hypertrophic cardiomyopathy. Although the mechanism of persistently positive 111In-Antimyosin Fab images in the subacute to chronic stage of myocardial infarction and myocarditis remains to be clarified, 111In-Antimyosin Fab may be useful for the detection of the diseases and in evaluating the prognosis of patients with cardiomyopathy.

Adult↗
PubMed1990

[Assessment of resting thallium-201 reinjection after stress-delayed Tl imaging (I): Comparison with 24-hour scan and regional wall motion].

Clinical value of resting reinjection of 1 mCi (37 MBq) of Tl after stress-delayed scan was assessed in comparison with 24 hr delayed scan and regional wall motion (RWM) in 37 patients with coronary artery disease. Of 101 segments with initial perfusion abnormality, concordant findings were observed after Tl reinjection in 67 segments (66%). But redistribution (RD) after Tl reinjection was observed in 19 of the 52 persistent defect (PD) segments (37%), and complete RD was observed 15 of the 43 segments (35%) where 3 hr scan showed incomplete RD. On the other hand, concordant findings were observed on 24 hr delayed scan in 11 of the 20 segments with perfusion abnormality (55%). RD on 24 hr delayed scan was observed in 5 of the 13 PD (38%), but it was not apparent in 3 of the 7 segments where 3 hr scan showed RD. Furthermore the segments which showed RD after Tl reinjection in PD segments tend to have less severe RWM abnormality than the sustained PD segments (RWM score: 1.65 +/- 1.17 vs. 2.29 +/- 1.05, p less than 0.05). These data indicate that Tl reinjection which permits assessment of RD with good quality images on the same day is considered as a valuable means for assessing myocardial viability.

Adult↗
PubMed1990

[Evaluation of complete left bundle branch block with normal coronary artery using positron emission CT (PET) and Tl-201 scintigraphy].

False-positive Tl-201 scintigraphy in patients with complete left bundle-branch block (CLBBB) and normal coronary artery had been reported by several authors. However the reason for this phenomenon remained to be clarified. We investigated 2 patients (case 1; a 65-year-old male, case 2; a 58-year-old male) with CLBBB using positron emission computed tomography (PET). Coronary angiography revealed normal coronary artery in both cases. In both cases, Tl-201 stress scintigraphy demonstrated definite perfusion defect at the anteroseptal region without redistribution, although PET study using F-18 fluorodeoxyglucose (18F-FDG) revealed defect at the septal wall. This indicates that perfusion defect detected by Tl-201 scintigraphy relates rather not to ischemic myocardium with a viable region, but to necrotic or fibrous tissue. Thus, PET is a useful tool in investigating viability of abnormal myocardium when other study has failed to do so. Our cases with CLBBB suggested that there was abnormal flow and metabolism at the anteroseptal region, possibly relating to the pathogenesis of CLBBB.

Aged↗
PubMed1989

Assessment of transesophageal Doppler echography in dissecting aortic aneurysm.

To assess the clinical value of transesophageal Doppler echography in the diagnosis of dissecting aortic aneurysm, both transesophageal and conventional echograms were performed in 22 cases of dissecting aortic aneurysm. Of the 22 patients, 17 underwent angiography; 8, X-ray computed tomography; 4, both; and 12, surgery. The performance of each method was assessed in the following four segments: A, ascending aorta; B, aortic arch; C, thoracic descending aorta; and D, upper abdominal aorta. The results by angiography were presumed to be correct. In the group of 17 patients who underwent angiography, the rate of correct detection of an intimal flap using the transesophageal approach was 100% in all four segments, significantly better than detection by the conventional approach (segment A, 65%; segment B, 47%; segment C, 35%; segment D, 53%) (p less than 0.01), and the rate of correct detection of the entry sites using the transesophageal approach was 100%, significantly better than that by conventional approach (42%) (p less than 0.05). X-ray computed tomography was not capable of detecting the site of entry in all cases. The presence of thrombus, aortic regurgitation and pericardial hemorrhage were all revealed clearly by the transesophageal approach, and the results were partly proved by other methods. In conclusion, transesophageal Doppler echography provides a rapid and accurate method of diagnosing and evaluating dissecting aortic aneurysm and permits prompt initiation of appropriate treatment.

Adult↗
PubMed1989

Mechanism for the generation of active smooth muscle inhibitory factor (IF) from bovine retractor penis muscle (BRP).

The active smooth muscle inhibitory factor (IF) is generated by acidifying the extracts from the bovine retractor penis muscle (BRP). The activated IF is very similar to endothelium-derived relaxing factor (EDRF). However, the mechanism for the generation of active IF is yet unknown. From reverse-phase high performance liquid chromatographic data, the activities of nitrite loss were closely related to the contents of both sulfhydryl (SH) groups and L-cysteine. Thus, under acidic conditions, RSH and nitrite in the extracts are considered to react as follows: RSH + HNO2----RSNO + H2O, RSNO----(1/2) RSSR + NO, NO + (1/2)O2----NO2, NO2 + (1/2)H2O----(1/2)HNO2 + (1/2)HNO3. In addition to NO, RSNO is also a labile but potent vasodilator. Thus, activated IF seems to consist of RSNO and NO, and thiol-containing small molecules (molecular weight of less than 1,000) from BRP are closely involved in the generation of active IF.

Animals↗
PubMed1989

Effects of intravenous administration of nicorandil on cardiovascular hemodynamics and left ventricular function.

The effects of the intravenous administration of the antianginal drug, nicorandil, 50 micrograms/kg administered over 2 minutes, were investigated during pacing-induced ischemia in 8 patients with coronary artery disease. Hemodynamic parameters were measured and single-plane left ventriculograms were obtained in control and postpacing periods both before and after pretreatment with nicorandil. Regional wall motion of the left ventricle was assessed by measuring shortening of the radial axes originating from the center of gravity of the end-diastolic silhouette. Heart rate, left ventricular (LV) systolic pressure and end-diastolic volume index did not change in the immediate postpacing period with or without medication. LV end-diastolic pressure decreased with nicorandil, from 22.0 +/- 3.4 to 17.0 +/- 2.3 mm Hg (mean +/- standard error of the mean) (p less than 0.05), and LV systolic volume index, from 39.6 +/- 8.0 to 30.4 +/- 6.8 ml/m2 (p less than 0.05). Ejection fraction increased from 55.2 +/- 5.0 to 64.3 +/- 3.8% (p less than 0.05). Stroke index and cardiac index (calculated from heart rate and stroke index) did not change significantly. Rapid right ventricular pacing increased the extent and degree of dyskinesia of the left ventricle, but premedication with nicorandil improved the wall motion. Thus, nicorandil has salutary effects on ventricular contractile and hemodynamic responses to transient ischemia induced by pacing stress.

Aged↗
PubMed1989

Multiple receptors for modified low density lipoproteins in mouse peritoneal macrophages: different uptake mechanisms for acetylated and oxidized low density lipoproteins.

Receptor-mediated incorporations of two modified low density lipoproteins (LDL), acetylated LDL (acetyl-LDL) and oxidized LDL were compared in vitro in mouse peritoneal macrophages by cross-competition experiments. Excess amount of oxidized LDL inhibits the binding of [125I]acetyl-LDL only partially, and excess amount of acetyl-LDL inhibits that of [125I]oxidized LDL also only partially, suggesting that the uptake of the two LDL by macrophages is mediated by partially overlapped yet different mechanisms. Scatchard analysis of [125I]acetyl-LDL binding showed a linear plot and addition of excess amount of oxidized LDL partially displaced the binding sites without changing the affinity, suggesting that there are two classes of receptors with similar affinity; one is specific for acetyl-LDL and the other is common. And the plot of [125I]oxidized LDL binding showed a curvilinear plot and excess amount of acetyl-LDL partially displaced the binding sites of the low affinity, suggesting that there are two classes of binding sites with different affinities and the low affinity one is shared with acetyl-LDL. These results indicate that macrophage receptors for modified LDL consist of at least three receptors, two of which are specific for each LDL and the rest is a common receptor.

Acetylation↗
PubMed1989

Usefulness of negative dP/dt upstroke pattern for assessment of left ventricular relaxation in coronary artery disease.

It has been reported that regional asynchrony due to acute ischemia disturbs the exponential nature of left ventricular (LV) pressure reduction and may alter the pattern of (-)dP/dt upstroke curve. If LV pressure decreases exponentially during the isovolumic relaxation period (P = Ae-t/T + B, where A and B = constants, t = time and T = time constant), the (-)dP/dt upstroke curve should also be exponential and upward-convex because dP/dt = A(-t/T)e-t/T. To test this theory in humans, the LV (-)dP/dt upstroke curve was analyzed in 9 normal subjects, 12 patients with effort angina pectoris (AP) and 15 with old myocardial infarction (MI) under the basal conditions. The (-)dP/dt upstroke was convex-upward in all normal subjects, but convex-downward in 9 of 12 patients with AP and in all patients with MI, which suggests nonexponential decrease in LV pressure in the groups with AP and MI. The dP/dt (20/60), which is the ratio of the (-)dP/dt value at 20 ms after peak (-)dP/dt to that at 60 ms after peak (-)dP/dt, was significantly lower in the group with AP (1.70 +/- 0.07) and in the group with MI (1.61 +/- 0.13) than in normal subjects (2.08 +/- 0.18) (p less than 0.005). This indicates that (-)dP/dt upstroke 20 to 60 ms after peak (-)dP/dt increases more slowly in the groups with AP and MI than in normal subjects. Theoretical consideration showed that such a slower increase of the upstroke resulted from impaired early to midrelaxation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗