Biomedical subjects
Publications and source records attributed to D Inoue.
We describe the M-mode and two-dimensional echocardiographic findings of a floating thrombus in the left atrium. Though the features resembled those of pedunculated left atrial myxoma, two-dimensional echocardiography was helpful in differentiating between thrombus and myxoma in the left atrium.
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A patient with click and late systolic murmur syndrome originating in the right side of the heart is described. Prolapse of the anterior tricuspid leaflet was demonstrated by subxiphoid two-dimensional echocardiography alone. Neither of the mitral leaflets showed any evidence of prolapse on the echocardiogram. The prolapsed anterior tricuspid leaflet and mild regurgitation were confirmed by right heart cineangiogram.
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A newly developed troponin T (TnT) test for the detection of myocardial cell necrosis has been reported to be very efficient in the detection of acute myocardial infarction. The aim of the present study was to determine whether cardiac TnT in coronary effluent from isolated heart perfused with albumin-free perfusion medium could be detected using the enzyme-linked immuno-sorbent assay developed by Katus et al. Isolated rat hearts were perfused according to the method of Langendorff. Coronary flow rate was measured by timed collection of the coronary perfusate that dripped from the hearts during 5 h of hypoxia (protocol A) or 4 h of hypoxia followed by 1 h of reoxygenation (protocol B). Creatine kinase (CK) and lactate dehydrogenase (LD) levels were compared with that of TnT. Myocardial adenine nucleotides were measured by HPLC. There was a strong correlation between TnT levels in albumin-free coronary effluent and TnT levels in coronary effluent diluted 1:1 with 5% bovine serum albumin (r = 0.996, N = 72). The coefficients of correlation between TnT and CK or LD during hypoxia and reoxygenation were 0.891 (N = 88) and 0.871 (N = 88), respectively. The coefficient of correlation between CK and LD was 0.993 (N = 88). There were no significant differences in either the decrease of coronary flow or the increase of TnT content between the hearts in the two protocols. There was no significant correlation between sigma TnT and energy charge of adenine nucleotides. These results indicate that cardiac TnT levels can be easily measured in albumin-free coronary effluent of isolated heart preparations.(ABSTRACT TRUNCATED AT 250 WORDS)
The aim of this study was to examine the effect of ischemic preconditioning on the releases of cardiac troponin T (TnT) during reperfusion in isolated rat hearts. Experiments were done on 22 rat hearts, which were perfused according to the method of Langendorff and were divided into the control group (n = 14) and the preconditioning group (n = 8). Double 5 min of ischemia each followed by 5 min reflow were applied as ischemic preconditioning. After 20 min of global ischemia, the releases of TnT, creatine kinase (CK), and lactate dehydrogenase (LD) in coronary effluent and the left ventricular developed pressure (LVP) were measured during 60 min of reperfusion. Ischemic preconditioning significantly suppressed the amounts of TnT released during reperfusion, as with those of CK and LD, and also improved contractile dysfunction (nine hearts in which ventricular fibrillation was sustained were excluded from the evaluation for hemodynamics), though the release kinetics of TnT was different from that of CK and LD. There were good inverse relationships between the LVP and the total amounts of TnT released during reperfusion period (sigma TnT) or TnT levels at 60 min of reperfusion. Cardiac TnT can be used as a useful biochemical marker for hemodynamics and myocardial damage after reperfusion.
Previously, we reported that cardiac troponin T (TnT) can be detected and measured in coronary effluent from isolated rat hearts during hypoxia. The present study was designed to evaluate the release kinetics of TnT from post-ischemic rat hearts. Using the Langendorff technique, the hearts were reperfused for 4 h after 20 min or 60 min of global ischemia. Coronary flow was measured by timing the collection of the coronary perfusate that dripped from the hearts, and left ventricular pressure (LVP) was monitored continuously during the experiments. The amount of TnT released in 1 min was compared with the release of creatine kinase (CK) and lactate dehydrogenase (LD). The release kinetics of CK and LD showed a monophasic pattern and the levels at 4 h after reperfusion returned to baseline levels. By contrast, the release kinetics of TnT showed a small peak followed by a larger and more sustained peak. There were good negative correlations between developed pressure of LVP and both sigma TnT and the amount of TnT released within 1 min at 4 h after reperfusion. These results indicate that the release kinetics of TnT is different from that of CK and LD during reperfusion, and further that cardiac TnT is a useful indicator of myocardial cell damage and can be used to evaluate the degree of myocardial cell damage in both the early and late phase of acute myocardial infarction.
Three cases are reported who have short runs of atrial premature contractions (APCs) induced by swallowing and cough. The occurrence of the APCs were affected by autonomic nervous system in all cases. The precipitating factor is considered to be the increase of vagal tone in case 1, sympathetic tone in case 2 and both of them in case 3. The autonomic mechanism of swallowing-induced tachycardia could be divided into three categories and the treatment of these arrhythmias might be different in each group. Pharmacological autonomic blockade with atropine and propranolol is useful to reveal the underlying autonomic mechanisms.