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Biomedical subjects

K Komamura

Publications and source records attributed to K Komamura.

84 records · Page 5Linked to original sources
PubMed1989

Preliminary clinical experience with intermittent coronary sinus occlusion in combination with thrombolytic therapy in acute myocardial infarction.

Previous experimental studies have clarified the effectiveness of intermittent coronary sinus occlusion or ICSO. We evaluated the clinical feasibility, safety and effectiveness of ICSO in the patients with acute myocardial infarction (AMI) who were treated with concomitant thrombolytic therapy. Implementation of ICSO was obtained in 76% of the eligible patients. Twelve patients with evolving anteroseptal infarction treated with ICSO + thrombolysis were compared with 12 patients with anterior AMI treated with thrombolysis alone. Baseline characteristics were comparable between the two groups. Adverse effects of ICSO on hemodynamics, hematologic parameters and ventricular arrhythmias were not detected. Enzymatic infarct size, myocardial lactate metabolism in the acute phase, and left ventricular wall motion and Tl-201 perfusion defect at follow-up in ICSO group were slightly improved compared with controls.

Adult↗
PubMed1989

[Serial myocardial lactate metabolic changes after intracoronary thrombolysis in evolving myocardial infarction].

To ascertain whether early intracoronary reperfusion (less than 3 hours) preserves aerobic myocardial metabolism in acute myocardial infarction, serial changes in trans-cardiac lactate extraction after intracoronary thrombolysis were examined in 35 patients with acute anteroseptal myocardial infarction. Eight patients without intracoronary reperfusion served as controls. In the chronic phase, we also observed abnormally contracting myocardial segments as an index of infarct size and the regional ejection fraction as an index of chronic regional cardiac function. In the early reperfusion group (less than 3 hours; 15 cases), positive lactate extraction was restored; there were small abnormally-contracting segments and a high regional ejection fraction. However, the intermediate reperfusion group (3-5 hours; 10 cases) had sustained anaerobic lactate extraction, large abnormally-contracting segments and a low regional ejection fraction. The late reperfusion (greater than 5 hours; 10 cases) group showed apparent aerobic lactate extraction, but had large abnormally-contracting segments and a low regional ejection fraction. Thus, early reperfusion preserves aerobic lactate metabolism and good ventricular function in the chronic phase.

Heart Ventricles↗
PubMed1988

Serial myocardial lactate metabolic changes after intracoronary thrombolysis in evolving myocardial infarction.

To investigate whether early reperfusion (less than or equal to 3 hours) preserves aerobic myocardial metabolism in acute myocardial infarction, we examined serial changes in trans-cardiac lactate extraction after thrombolysis in 43 patients with acute antero-septal myocardial infarction. In the chronic phase, we also determined abnormally contracting segments as an index of infarct size and regional ejection fraction as an index of chronic regional cardiac function. In the early reperfusion group (less than or equal to 3 hours), positive lactate extraction was restored and there were small abnormally contracting segments and a high regional ejection fraction. The intermediate reperfusion group (3-5 hours), however, had sustained anaerobic lactate extraction, large abnormally contracting segments and a low regional ejection fraction. The late reperfusion (greater than 5 hours) group showed apparently aerobic lactate extraction, but had large abnormally contracting segments and a low regional ejection fraction. Thus, early reperfusion preserves aerobic lactate metabolism and good chronic ventricular function.

Adult↗
PubMed1987

Acute electrocardiographic changes associated with successful coronary thrombolysis in acute myocardial infarction.

In this study ECG changes were analyzed to assess the acute effects of antegrade blood flow on the ECG in patients with AMI. The study population consisted of 22 patients with MI in whom the totally occluded left anterior descending artery (LAD) or right coronary artery (RCA) was recanalized by intracoronary urokinase infusion (recanalized group) and 14 patients in whom the occluded coronary artery was not successfully recanalized (control group). No significant difference was found in the sum of ST segment elevation (V2-V4 leads for the LAD-occluded group, II, III and aVF leads for the RCA-occluded group) before urokinase infusion. In the recanalized group sigma ST abruptly increased in 5 min after recanalization in 13 of 16 LAD-occluded patients from 1.49 +/- 0.89 mV to 2.44 +/- 1.67 mV (p less than 0.005), and in 4 of 6 RCA-occluded patients from 0.66 +/- 0.12 mV to 1.42 +/- 0.52 mV (p less than 0.01). However increased sigma ST in the recanalized group was reduced to the control value existing before recanalization within 30 min after recanalization and continued to decline more rapidly than in the control group. These transient ST segment elevations were not correlated with long-term angiographic determinants of left ventricular function. We conclude that ST segment shows abrupt augmentation after successful thrombolysis and that continuous ST segment monitoring is useful for assessing thrombolysis in AMI.

Adult↗
PubMedDate not supplied

Reduced 3H-ouabain binding site (Na,K-ATPase) concentration in ventricular myocardium of dogs with tachycardia induced heart failure.

The present study evaluates 3H-ouabain binding site (Na,K-ATPase) concentration in left ventricular myocardium of dogs with heart failure induced by tachycardia as a result of ventricular pacing. Samples of left ventricle were obtained from 10 dogs exposed to pacing of 240 beats/min for 3 to 4 weeks and eight sham-operated controls. Na,K-ATPase was quantified using vanadate facilitated 3H-ouabain binding to intact samples. At time of sacrifice paced dogs showed clinical signs of heart failure, a significant 257% increase in left ventricular end diastolic pressure and a significant 46% decrease in left ventricular dP/dt compared with control. There was no significant change in left ventricular mass. 3H-ouabain binding concentration was significantly reduced by 16%. Evaluation of 3H-ouabain binding kinetics revealed no significant difference between myocardium from paced and control dogs: Equilibrium binding conditions were at the various concentrations used obtained after similar incubation time; nonspecific uptake and retention of 3H-ouabain was 0.9-0.8% of total uptake and retention obtained in the standard assay; apparent dissociation constant (KD) was 6.5 x 10(-8)-6.6 x 10(-8) mol/l; loss of specifically bound 3H-ouabain during washout at 0 degrees C occurred with a half-life time (T1/2) of 120 and 121 h. Hence, total 3H-ouabain binding site concentration in left ventricular myocardium was (mean +/- SEM) 1110 +/- 56 and 1317 +/- 68 pmol/g wet weight, 8.54 +/- 0.43 and 10.05 +/- 0.52 pmol/mg protein, and the total amount of 3H-ouabain binding sites in the entire left ventricle 121 +/- 6 and 162 +/- 8 nmol in paced (n = 10) and control (n = 8) dogs (p < 0.05), respectively. In conclusion, the present study reports a significant reduction in left ventricular myocardium 3H-ouabain binding site concentration in tachycardia induced heart failure. This observation supports the concept of a relationship between Na,K-ATPase concentration and contractile capacity and may be of pathophysiological importance in tachycardia and heart failure.

Animals↗
PubMedDate not supplied

Haplotype structures of the UGT1A gene complex in a Japanese population.

Genetic polymorphisms of UDP-glucuronosyltransferases (UGTs) are involved in individual and ethnic differences in drug metabolism. To reveal co-occurrence of the UGT1A polymorphisms, we first analyzed haplotype structures of the entire UGT1A gene complex using the polymorphisms from 196 Japanese subjects. Based on strong linkage disequilibrium between UGT1A8 and 1A10, among 1A9, 1A7, and 1A6, and between 1A3 and 1A1, the complex was divided into five blocks, Block 8/10, Block 9/6, Block 4, Block 3/1, and Block C, and the haplotypes for each block were subsequently determined/inferred. Second, using pyrosequencing or direct sequencing, additional 105 subjects were genotyped for 41 functionally tagged polymorphisms. The data from 301 subjects confirmed the robustness of block partitioning, but several linkages among the haplotypes with functional changes were found across the blocks. Thus, important haplotypes and their linkages were identified among the UGT1A gene blocks (and segments), which should be considered in pharmacogenetic studies.

Asian People↗
PubMedDate not supplied

Recovery of cardiac function by long-term left ventricular support in patients with end-stage cardiomyopathy.

Effects of long-term left ventricular (LV) support on end-stage cardiomyopathy patients is unclear. We applied our LV assist system (LVAS) to six heart transplant candidates, aged 17 to 49, with dilated cardiomyopathy, including one dilated phase hypertrophied cardiomyopathy. LVAS was installed between the left atrium and the ascending aorta, and the pump was positioned parecorporeally. In all patients, their general condition improved, and their pump flows were kept at 4 to 5 L/min. Exercise was started after stabilization of their general condition under constant pump flow. Natural heart size and function were examined by echocardiography. In the beginning of assist, all patients showed impaired cardiac function and LV dilation. During LV assist, systolic function measured by ejection time improved in all patients. Left ventricular end-diastolic dimension (LVDd), showed a remarkable decrease in two patients, who were weaned from LVAS after 3 months of support. They are doing well more than 1 year and 3 years after removal; peak VO2 levels (ml/min/kg) were 30 at 1.2 years and 27 at 2.7 years after removal. In the other four patients, however, LVDd had no remarkable changes, and three could not be weaned from LVAS. The last was discontinued from LVAS after 5 months of support because of infection and died 2 months after removal. From this experience, long-term LVAS may provide the chance for recovery of the natural heart in patients with end-stage cardiomyopathy. The patients whose hearts showed remodeling were able to be weaned from LVAS, and their heart function maintained in good condition for several years.

Adolescent↗
PubMedDate not supplied

Human plasma superoxide dismutase (SOD) activity on reperfusion injury with successful thrombolysis in acute myocardial infarction.

Generation of oxygen free radicals at the time of reperfusion has been implicated as a major causative factor for myocardial reperfusion injury. In order to examine if oxygen free radical scavenger superoxide dismutase (SOD) in human plasma prevent reperfusion injury with successful thrombolysis and limit infarct size, we studied the relationship between infarct size and plasma SOD activity in 25 patients received thrombolytic therapy in antero-septal acute myocardial infarction. Plasma SOD activities were measured by the nitrate method. There was no variance in plasma SOD activity in patients with acute myocardial infarction before and after thrombolysis. Infarct size was evaluated by using % abnormally contracting segments (% ACS) correlation with % ACS (r = -0.58, p less than 0.05) in 17 patients with successful thrombolysis. This significant correlation was still shown in 14 patients without collaterals before recanalization (r = -0.56, p less than 0.05). On the other hand, there was no significant relationship between plasma SOD activities and % ACS in 8 patients with a complete occlusion after thrombolysis (r = -0.081). These results showed that human plasma SOD prevent the reperfusion injury and limit the infarct size in patients with successful thrombolysis and imply that the generation of free radical at the time of reperfusion results in myocardial reperfusion injury.

Adult↗