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Biomedical subjects

S Kusachi

Publications and source records attributed to S Kusachi.

At least 73 records · Page 4Linked to original sources
PubMed1993

Auto-antibody against adenine nucleotide translocator in dilated cardiomyopathy and myocarditis--incidence and relation to cardiac function and morphology.

Using an enzyme-linked immunosorbent assay, we measured anti-adenine nucleotide translocater (ANT) antibody in control subjects and in patients with dilated cardiomyopathy (DCM), myocarditis, and other heart disease. Analysis with sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blotting, and immunoabsorption tests confirmed accurate purification of the ANT protein and correct measurement of anti-ANT auto-antibody. Anti-ANT antibody was detected in 6 of 37 cases (16%) of DCM and in 5 of 12 cases (42%) of myocarditis. This antibody was not positive in other heart diseases or in apparently healthy controls. There were no differences between anti-ANT autoantibody-positive and -negative DCM or myocarditis patients in any of the cardiac parameters examined (left ventricular ejection fraction, LVEF; left ventricular end-diastolic dimension, LVDd; and cardiothoracic ratio, CTR). Moreover, in patients who were positive for anti-ANT auto-antibody, no positive correlations were found between the parameters and anti-ANT antibody titers in either DCM or myocarditis. Although these results indicate that the detection of anti-ANT antibody was achieved at a high specificity and could have certain diagnostic value in DCM and myocarditis, there was no statistically significant relationship between the cardiac parameters (LVEF, LVDd, and CTR) and anti-ANT antibody titers in either DCM or myocarditis. Some compensatory mechanism of ventricular function may mask the effects of the anti-ANT auto-antibody or alternatively, this auto-antibody may have mimic effects on the pathogenesis and/or progression of DCM and myocarditis.

Adult↗
PubMed1993

Acute left main coronary artery obstruction with myocardial infarction--reperfusion strategies, and the clinical and angiographic outcome.

We studied the clinical and angiographic outcomes in 8 patients with acute left main coronary artery obstruction. Intracoronary thrombolysis with 1.2 x 10(5) units of urokinase was performed in 3 patients during preparation for percutaneous transluminal coronary angioplasty (PTCA), and failed in all 3 cases. In 2 patients, the left main coronary artery was recanalized by intracoronary thrombolysis with 3.6 and 4.8 x 10(5) units of urokinase, respectively. PTCA was attempted either before or after intracoronary thrombolysis in 5 patients and achieved reperfusion in all 5 cases. However, 2 of the 8 patients had persistent high-grade residual stenosis 69% and 89% luminal reduction, respectively. Emergency coronary artery bypass grafting was successfully performed in these 2 patients, and both are currently alive. Although intraaortic balloon counterpulsation was performed in all 8 patients, 2 died acutely from pump failure in the catheterization laboratory. One patient died later due to congestive heart failure. The factors favoring survival were right coronary artery dominance and a well-developed collateral circulation. Our findings suggest that PTCA is a useful strategy for reperfusion following acute left main coronary artery occlusion. When PTCA cannot achieve sufficient revascularization, emergency coronary artery bypass grafting should be performed. To control pump failure, intraaortic balloon counterpulsation is insufficient in some cases and more aggressive measures may be required.

Aged↗
PubMed1993

Histological abnormalities in a biopsy specimen obtained from the left ventricle without reduced function in a patient with right ventricular dysplasia.

Left ventricular histological examination was performed in a patient with right ventricular (RV) dysplasia. Although the left ventricle (LV) appeared to have a normal shape and function, the LV biopsy specimen revealed apparent myocyte hypertrophy and substantial fibrotic changes without fatty infiltration. It was not clear whether these considerable histological changes were part of right ventricular dysplasia or not. The present case indicates that even with normal LV shape and function in patients with right ventricular dysplasia, histological examination of LV may provide additional information on its pathogenesis and prognosis.

Aged↗
PubMed1992

Effects of reperfusion on left ventricular ejection fraction and volume after acute myocardial infarction.

The effects of reperfusion on left ventricular (LV) function and volume were studied in patients with evolving acute myocardial infarction (AMI). We analyzed the LV ejection fraction and volume in patients who had been admitted within 24 h of the onset of their first AMI with culprit lesion of #6, #7 and #1 (American Heart Association classification). Sixty-five patients (Re group) received successful reperfusion therapy within 6 h after the AMI. The other 60 patients (Oc group), who were admitted from 6 to 24 h after the AMI, received conservative therapy. Patients with re-obstruction of the culprit lesion after reperfusion therapy were excluded from the Re group. Patients with spontaneous recanalization following conservative therapy were excluded from the Oc group. The LV ejection fraction (LVEF), LV end-systolic volume index (LVESVI), and LV end-diastolic volume index (LVEDVI) were measured using a modified Dodge's formula by left ventriculography performed 4 weeks after the AMI. LVEF in the Re group was significantly greater than in the Oc group (57 +/- 12 vs 49 +/- 11%) (mean +/- SD, p less than 0.01). LVESVI in the Re group was significantly smaller than in the Oc group (30 +/- 13 vs 38 +/- 16 ml/m2, p less than 0.01). Although LVEDVI was not significantly different between the 2 groups, in patients with a responsible coronary lesion of segment #6, LVEDVI in the Re group was significantly smaller than in the Oc group (67 +/- 14 vs 77 +/- 18 ml/m2, p less than 0.05). Although LVEF and LV volume correlated in both groups, the correlation was weak (r = 0.40-0.42), suggesting that LV volume was not dependent solely on LV functional recovery. The incidence of ventricular aneurysm in the Re group was significantly lower than in the Oc group (15.4 vs 45.0%, p less than 0.01). Multivariate analysis selected reperfusion of the responsible coronary artery as one of the factors significantly associated with a reduction of LVEDVI, LVESVI, an improvement of LVEF, and a decrease in the rate of aneurysm formation. In summary, our results indicated that reperfusion improved EF, reduced LV volume, and decreased the rate of aneurysm formation as compared to non-reperfusion, which suggests that reperfusion therapy is beneficial for both functional recovery and ventricular remodeling.

Adult↗
PubMed1992

Emergency coronary angioplasty for acute myocardial infarction--factors affecting acute restenosis in catheterization laboratory and reocclusion during hospitalization.

A total of 107 consecutive patients with acute myocardial infarction underwent emergency coronary angioplasty (PTCA). Restoration of blood flow with TIMI grade III was established by emergency PTCA in 101 patients (94.4%). "Acute restenosis" was defined as a lesion that, when dilated to less than 50%, narrowed again to more than 75% luminar reduction 5 min after the balloon inflation. Acute restenosis occurred in 39 patients (39%). Multivariate analysis selected 3 factors associated significantly with an increased rate of acute restenosis: (1) dissection, (2) small balloon/artery diameter ratio and (3) low systolic blood pressure during PTCA. Reocclusion, which was defined as a total reobstruction of the lesion during hospitalization following emergency PTCA, was examined by predischarge coronary angiography. Acute restenosis correlated significantly with an increase in reocclusion rate. The incidence of documented reocclusion was 12%. Residual stenosis, multivessel disease and irregular dilation correlated significantly with an increased rate of reocclusion. The in-hospital and postdischarge mortalities were 5.6% and 2.1%, respectively. In summary, emergency PTCA produced a high angiographic success rate. Use of adequate balloon size and sufficient dilation correlated significantly with angiographic outcome in emergency PTCA. Patients with acute restenosis, high residual stenosis, irregular dilation, and multivessel disease would have a relatively high risk of reocclusion.

Adult↗
PubMed1992

NG-nitro-L-arginine attenuates flow debt repayment in the reactive hyperemic response of the open-chest dog coronary artery: contribution of endothelium-derived relaxing factor.

To test the hypothesis that the endothelium-derived relaxing factor (EDRF) contributes to coronary vasodilation induced by myocardial ischemia, we examined the effect of NG-nitro-L-arginine (a potent and selective inhibitor of EDRF release) on the coronary reactive hyperemic response in the open-chest dogs. Intracoronary infusion of NG-nitro-L-arginine at a coronary plasma concentration of 5 x 10(-5) M had no effect on hemodynamics and myocardial oxygen metabolism, but attenuated repayment of the flow debt by an average of 20.4% and 20.0% following coronary occlusion for 10 sec and 20 sec, respectively. Concomitant infusion of NG-nitro-L-arginine at the same concentration and 8-phenyltheophylline (a potent adenosine receptor blocker) at a coronary plasma concentration of 10(-5) M further attenuated flow debt repayment following 10 sec and 20 sec of coronary occlusion by 47.7 and 59.4%, respectively. These results indicate that EDRF plays a significant role in the coronary reactive hyperemic response and may cause vasodilation independently of adenosine-mediated vasodilation following coronary occlusion.

Adenosine↗
PubMed1992

[Managements of hospital MRSA infections in digestive tract surgery].

1444 cases if digestive tract surgery in our department were studied for the prevention of postoperative MRSA infections, during the period from September 1987 to February 1992. They were divided into nine stages each six months. There were no significant differences in incidence of postoperative MRSA infections, after some managements for hospital infection among each stage. We used the antibiotics as follows; the first generation of cefem families was used for the upper digestive tract operations and the second generation of cefem families was used for the lower digestive tract operation, and the incidence of postoperative MRSA infections were diminished significantly. This study showed that managements for hospital infections and appropriate selection of antibiotics for the purpose of postoperative prophylactic use are effective for the prevention of MRSA infections.

Cephalosporins↗
PubMed1991

Improvement of left ventricular aneurysm after myocardial infarction: report of three cases.

We report on the disappearance of a left ventricular aneurysm after myocardial infarction in three cases. Coronary blood flow was restored by spontaneous recanalization in two cases and by angioplasty in one case. When the aneurysm was observed, the findings in these cases were (1) no or limited abnormal Q wave in surface electrocardiography, (2) total or subtotal stenosis of the proximal coronary artery without adequate distal filling through collaterals, (3) no ST shift in exercise electrocardiography, and (4) decreased but not absent thallium-201 uptake in myocardial scintigraphy. In Cases 1 and 2, respectively, 3 years and one year and 8 months after the myocardial infarction, an anginal episode occurred and the ventricular aneurysm disappeared. In Case 3, the aneurysm disappeared after coronary angioplasty. These cases suggest that even without a demonstration of reversible ischemic myocardium and/or severe stenosis without distal filling through collaterals, the myocardium presenting a ventricular aneurysm would be hibernating. These cases were also informative about the detection of hibernating myocardium.

Aged↗
PubMed1991

Oxygen metabolism of the hypertrophic right ventricle in open chest dogs.

STUDY OBJECTIVE: The aim was to investigate oxygen metabolism of the hypertrophic right ventricle in anaesthetised open chest dogs. DESIGN: Right ventricular hypertrophy was induced by right ventricular pressure overload with banding the pulmonary artery for six months. Coronary blood flow and myocardial oxygen metabolism of the hypertrophic right ventricle were determined during control and after increasing right ventricular oxygen consumption, and compared with those of the normal right and left ventricles. SUBJECTS: Seven mongrel dogs with right ventricular hypertrophy and 21 normal dogs were used. All were anaesthetised with pentobarbitone sodium. MEASUREMENTS AND MAIN RESULTS: Oxygen extraction [(A-V)O2] of the hypertrophic right ventricular myocardium was greater than that of normal right ventricle in controls and almost identical to the (A-V)O2 of the normal left ventricle. It showed no increase when coronary blood flow and right ventricular oxygen consumption were raised in response to a further elevation of the right ventricular pressure and isoprenaline infusion. However, the right ventricular interventions which increased right ventricular oxygen consumption produced an elevation of (A-V)O2 of the right ventricle with an increase in right coronary blood flow. CONCLUSIONS: Higher oxygen extraction during control and no response of oxygen extraction of the hypertrophied right ventricle in response to stimuli which increase right ventricular oxygen consumption indicate that oxygen supply to the hypertrophic right ventricle is different from that of the normal right ventricle, and is more like that of the left ventricle.

Animals↗
PubMed1991

Interaction between adenosine and beta-adrenoceptors.

Interaction between adenosine and isoproterenol (ISP) on myocardial inotropic action was studied in open-chest dog hearts. The local myocardial force and the left ventricular (LV) dP/dt were measured as indices of myocardial contractility. Isoproterenol [ISP, 9.47 microM (2 micrograms/ml)] was infused into the left circumflex coronary artery at rates of 0.05 ml/min (low dose ISP) or 0.2 ml/min (high dose ISP). Two mM adenosine or 0.5 mM N6-phenylisopropyl-adenosine (PIA) were infused into the coronary artery at rates of 0.2 (4 x 10(-7) mol/min), 0.5 (1 x 10(-6) mol/min) and 10 ml/min (2 x 10(-5) mol/min) in the presence of either a low or a high dose of ISP. Adenosine infusion at a rate of 0.2 ml/min did not modify myocardial contractility in the presence of the both doses of ISP. The larger doses of adenosine, 0.5 ml/min and 10 ml/min, decreased myocardial-developed tension and LVmax dP/dt dose-dependently. However, the dose of adenosine which affected myocardial contractility was inphysiologically high in comparison with the concentration in the ischemic myocardium. PIA, a potent agonist of adenosine A1-receptor, attenuated an increase in myocardial contractility in a dose-dependent manner which was caused by intracoronary ISP infusion. This indicates that A1-adenosine receptors exist, but a functional adenosine-catecholamine antagonism does not play a significant role in the canine left ventricle.

Adenosine↗
PubMed1991

Association between high grade ventricular arrhythmia and extent of left ventricular hypertrophy in hypertrophic cardiomyopathy.

The association between the extent of left ventricular (LV) hypertrophy and severity of ventricular or atrial arrhythmias are examined. Two-dimensional echocardiography and 24-h Holter electrocardiography monitoring were performed in 60 patients with hypertrophic cardiomyopathy (HCM). According to the distribution of the LV hypertrophy, the patients were divided into three groups: 1. Apical hypertrophy (APH), 2. Septal hypertrophy, and 3. Extensive hypertrophy. Ventricular arrhythmias were found in 82% of the patients and supraventricular arrhythmias were detected in 70% of the patients. Lown grade III and IV arrhythmias occurred significantly more frequently in patients with extensive than with septal hypertrophy. Lown grade III to IV arrhythmias did not occur in patients with APH. Present results show a significant association between the extent of LV hypertrophy and the severity of ventricular arrhythmias in HCM.

Adult↗
PubMed1991

[The prediction of the need for postoperative mechanical ventilation in patients with myasthenia gravis undergoing transsternal thymectomy].

During a sixteen-year period, 51 patients with myasthenia gravis underwent trans-sternal thymectomy including extended resection of the adipose tissue around thymus. Using the criteria of risk factors described by Leventhal and Kimura, a predictive score was assessed for our 51 patients. Leventhal's scoring system achieved an accuracy of 54.3%, a sensitivity of 20.0% and a specificity of 63.9%. And, Kimura's scoring system achieved an accuracy of 75.0%, a sensitivity of 81.8% and a specificity of 73.0%. From this study it was concluded that Kimura's scoring system is statistically more adaptive for Japanese than Leventhal's scoring system, and the Leventhal's accuracy may have increased by adding "bulbar symptoms" and "preoperative crisis" as other risk factors and by decreasing "points" for "duration of myasthenia" and "pyridoxamine dosage", and the "Kimura's " accuracy may have increased by decreasing "7 points" for preoperative crisis. Consequently, patients who received postoperative ventilation were compared with the group who did not, with respect to the 19 factors. Evidence is that Osserman's type, bulbar symptoms, preoperative crisis and preoperative % VC were influenced to require the postoperative ventilation, but sex, age, thymic histology, duration of myasthenia and pyridoxamine dosage were not any influenced to require the postoperative ventilation.

Adult↗
PubMed1990

Reactive hyperaemic flow characteristics of the right coronary artery compared to the left anterior descending coronary artery in the open-chest dog.

Reactive hyperaemia, the cardiovascular response to transient occlusion of a vessel, was examined and compared in the right coronary artery (RCA) and the left anterior descending coronary artery (LAD) in the same heart of an open-chest dog. First, to study the relationship between reactive hyperaemia and occlusion time in the RCA and LAD, respective flows were measured and reactive hyperaemia was induced with different occlusion times. Occlusion time required for half the maximum peak percentage reactive hyperaemic flow (%PRH), t 1/2, for the RCA was approximately twice that of the LAD: 11.4 +/- 2.3 s versus 5.9 +/- 1.4 s. Maximum %PRH of the RCA was significantly greater than that of the LAD while the percentage repayment of the RCA was lower than that of the LAD. Augmentation of right ventricular oxygen consumption shortened t 1/2 and increased percentage repayment significantly. Second, to determine "critical pressure", which was defined as the perfusion pressure below which reactive hyperaemia was abolished completely, the RCA and LAD were perfused through a shunt from the carotid artery, perfusion pressure was varied in the range of 100 to 20 mmHg and reactive hyperaemia was induced. Critical pressure in the RCA was significantly lower than in the LAD: 32.2 +/- 5.7 mmHg versus 41.5 +/- 5.0 mmHg. These results suggest that the RCA has a greater flow reserve than the LAD. These results were consistent with the difference of oxygen metabolism between the right and left ventricles. The difference of oxygen metabolism between the two ventricles would, at least partly, account for these results.

Animals↗
PubMed1990

Autoregulation by the right coronary artery in dogs with open chests; comparison with the left coronary artery.

Experiments were conducted to study autoregulatory responses of the right and left coronary arteries in dogs with open chests. The right and left circumflex coronary artery were cannulated and perfused with blood from the femoral artery via a pressurized reservoir. The perfusion pressure was varied in steps over a wide range and coronary blood flow rates were measured. Both the right and left coronary arteries exhibited autoregulation but the pressure at the end of the autoregulatory range was lower in the right (39.8 +/- 9.1 mm Hg) than in the left circumflex coronary artery (57.6 +/- 14.5 mm Hg). The slope of the pressure-flow relationship in the autoregulatory range was less steep in the right than the left circumflex coronary artery. The closed-loop gain when the perfusion pressure was less than 100 mm Hg was greater in the right than in the left circumflex coronary artery. Increases in the right ventricular afterload produced by pulmonary artery constriction decreased the closed-loop gain, shifted the auto-regulatory range upward and to the right, and made the slope steeper. These results indicate that more effective autoregulation is carried out by the right than the left circumflex coronary artery.

Animals↗
PubMed1990

[Chronic intractable pericardial effusion associated with pulmonary hypertension: report of two cases].

We report two cases of chronic intractable pericardial effusion associated with pulmonary hypertension. Case 1. A 35-year-old women was admitted to our hospital because of dyspnea and edema. Chest X-ray examination showed enlargement of cardiac, and pulmonary artery shadow. An electrocardiogram with high voltage of R in V1 and deep S in V5 suggested right ventricular hypertrophy. Pericardial echo-free space with dilated right ventricle was demonstrated by echocardiography. Cardiac catheterization revealed an elevated pulmonary systolic pressure of 120 mmHg. No intracardiac shunt was calculated. A diagnosis of primary pulmonary hypertension was made. Pericardial drainage diminished pericardial effusion. Soon after discharge, however, pericardial effusion increased and the patient died. Case 2. A 65-year-old man was admitted because of dyspnea. The findings of chest X-ray and echocardiography were essentially the same as Case 1. Pericardial effusion disappeared after pericardiocentesis, but appeared again one month later. Cardiac catheterization demonstrated an elevated pulmonary systolic pressure of 73 mmHg. Pulmonary-capillary-wedge pressure was normal. Pulmonary arteriogram showed occlusion of the pulmonary artery trees. A diagnosis of chronic thromboembolic pulmonary hypertension was made. Although diuretics and vasodilators decreased pulmonary-artery pressure, pericardial effusion was unchanged. We compared these two cases with 11 control patients of pulmonary hypertension without pericardial effusion. Venous pressure was higher than that in the controls in Case 1, but not different in Case 2. Thus, venous pressure did not fully account for pericardial effusion. In summary, chronic pulmonary hypertension should be added to the list of conditions known to cause pericardial effusion. In these cases, echocardiography revealed important signs, and cardiac catheterization was essential for definite diagnosis. Pericardial effusion associated with pulmonary hypertension was refractory to diuretics and vasodilators.

Adult↗
PubMed1989

Reperfusion through balloon catheter to minimize myocardial infarction during the interval between failed percutaneous transluminal coronary angioplasty and emergency coronary artery bypass grafting.

A 65-year-old man was admitted with chest pain. A diagnosis of spastic angina was made because of symptoms of recurrent anginal attacks associated with ST-segment elevations in the electrocardiogram. A selective coronary arteriogram revealed a 90% diameter narrowing of the proximal left anterior descending coronary artery (LAD). No angiographically visible collaterals from the right coronary artery to the LAD were observed. The ventriculogram showed normal contraction of the left ventricle with an ejection fraction of 65%. Percutaneous transluminal coronary angioplasty (PTCA) failed resulting in total occlusion of the stenosis. Repeat PTCA at a higher pressure and of longer duration failed to redilate the artery. Reperfusion with the blood from the femoral artery through the balloon catheter, which was used for the PTCA, was carried out until coronary artery bypass grafting (CABG). Blood flow rate of perfusion was approximately 25 ml/min. Reperfusion through the balloon catheter reduced chest pain and ST-segment elevations in the electrocardiogram. The patient tolerated the operative procedure well and his post-operative course was uncomplicated. The interval between the acute occlusion and revascularization by CABG was approximately 4 1/4 h. The ventriculogram taken 56 days after the CABG demonstrated normal contraction of the anterior wall of the left ventricle with an ejection fraction of 63%. Abnormal Q waves did not appear in precordial leads of the electrocardiogram after the surgery. The thallium scintigram showed no perfusion defects. In conclusion, this case suggested that autologous blood reperfusion through balloon catheter would be worth attempting in some cases for minimization of myocardial infarction during the interval between failed PTCA and emergency CABG.

Angioplasty, Balloon, Coronary↗
PubMed1989

Forskolin potentiates myocardial reactive hyperaemia in the open chest dog: the contribution of adenylate cyclase.

Forskolin, a diterpene, directly stimulates adenylate cyclase and also potentiates receptor mediated stimulation of this enzyme by many stimulatory agonists. We exploited the potentiating effect of forskolin to test the hypothesis that activation of adenylate cyclase contributes to myocardial reactive hyperaemia, especially by release of adenosine at the time of brief coronary occlusions. In 10 open chest dogs, intracoronary forskolin infusions which produced plasma concentrations between 0.22 and 0.34 mumol.litre-1 slightly increased coronary blood flow and had no effect on haemodynamics or myocardial metabolism. Under these conditions, though peak reactive hyperaemic flow rates were not affected, forskolin infusions reversibly potentiated repayments of flow debt by 28, 25 and 27% following coronary occlusions of 15 s, 20 s and 30 s, respectively (p less than 0.05). In another seven dogs, after observations of the effects of forskolin (0.16-0.26 mumol), 10 mumol of 8-phenyltheophylline, a potent adenosine antagonist, was infused simultaneously with forskolin into the coronary arteries. Forskolin increased debt repayments by about 23-27% following 15 s, 20 s and 30 s occlusions, but with simultaneous 8-phenyltheophylline, forskolin induced increments in the debt repayments were reduced significantly (p less than 0.05). These results indicate that adenylate cyclase contributes to myocardial reactive hyperaemia, and adenosine has a significant role as metabolic regulator of reactive hyperaemia through activation of adenylate cyclase.

Adenosine↗