PubMed Health⌕ Search

Biomedical subjects

N Takekoshi

Publications and source records attributed to N Takekoshi.

At least 37 records · Page 2Linked to original sources
PubMed1995

Noninvasive prediction of coronary atherosclerosis by quantification of coronary artery calcification using electron beam computed tomography: comparison with electrocardiographic and thallium exercise stress test results.

OBJECTIVES: This study was designed to compare the usefulness of electron beam computed tomography for prediction of coronary stenosis with that of electrocardiographic (ECG) and thallium exercise tests. BACKGROUND: Electron beam computed tomography can quantify coronary calcifications; however, its clinical value has yet to be established. METHODS: Using the volume mode of electron beam computed tomography, we studied 251 consecutive patients who underwent elective coronary angiography because of suspected coronary artery disease and compared the results with those of ECG and thallium exercise tests. The total coronary calcification score was calculated by multiplying the area ( > or = 2 pixels) of calcification (peak density > or = 130 Hounsfield units) by an arbitrarily weighted density score (0 to 4) based on its peak density. The mean of two scans was log transformed. RESULTS: Calcification was first noted in women in the 4th decade of life, approximately 10 years later than its occurrence in men. Among patients with advanced atherosclerosis (two- and three-vessel disease), calcification scores were uniformly high in women but ranged widely in men. Nine percent of patients with significant stenoses ( > or = 75% by densitometry) had no calcification. The calcification scores of patients with significant stenosis in at least one vessel were significantly higher than those of patients without significant stenosis in the study group as a whole and in most patient subgroups classified according to age and gender. A cutoff calcification score for prediction of significant stenosis, determined by receiver operating characteristic curve analysis, showed high sensitivity (0.77) and specificity (0.86) in all study patients; sensitivity was similarly high even in older patients ( > or = 70 years) and was enhanced in middle-aged patients (40 to < or = 60 years). The difference in specificity between calcification scores and ECG exercise test results had borderline significance (p = 0.058) and that between calcification scores and thallium test results was significant (p = 0.001). The latter difference became small but remained significant (p = 0.01) even after the reevaluation of thallium test results in light of each subject's clinical data. CONCLUSIONS: Quantification of coronary artery calcification with electron beam computed tomography noninvasively predicted angiographically confirmed coronary stenosis. Results obtained with this method were at least as useful and potentially better in some patient groups than those obtained with thallium and ECG exercise testing.

Adolescent↗
PubMed1995

Assessment of working skeletal muscle oxygenation in patients with chronic heart failure.

Patients with chronic heart failure (CHF) are frequently limited by muscle fatigue resulting from impaired skeletal muscle blood flow. Accordingly, we assessed working skeletal muscle oxygenation in such patients using near-infrared (NIR) spectroscopy. Nine normal subjects (mean age 52 years) and 12 patients with CHF (mean age 60 years) were studied. NIR spectroscopy was used to monitor relative changes in oxygenated hemoglobin (Hb) and myoglobin (Mb) (oxy Hb/Mb), deoxygenated Hb and Mb (deoxy Hb/Mb), and total (oxy + deoxy) Hb and Mb (total Hb/Mb) contents in the vastus lateralis muscle at rest, during warm-up (0 W, 30 cycles/min for 3 min), incremental maximal supine bicycle exercise (ramp protocol, 15 W/min, 50 cycles/min), and recovery. At peak exercise the patients exhibited reduced heart rate, systolic blood pressure, peak exercise oxygen consumption (VO2; 15 +/- 3.0 ml/kg/min vs 32 +/- 8.5 ml/kg/min), and workload (99 +/- 23.4 W vs 183 +/- 68.4 W) as compared with the normal subjects. The respiratory quotient was comparable in both groups. In the normal subjects, oxy Hb/Mb was increased from the warm-up period to the early phase of exercise, followed by a progressive decrease to peak exercise. In the recovery phase, oxy Hb/Mb was increased abruptly. For these patients, change in oxy Hb/Mb followed a pattern similar to that seen in normal subjects, and oxy Hb/Mb was decreased earlier in contrast to that in the normal subjects. There was a significant difference in the change of oxy Hb/Mb during warm-up, early phase exercise, and recovery between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise Test↗
PubMed1995

Dilated cardiomyopathy defines serum autoantibodies against G-protein-coupled cardiovascular receptors.

In order further to identify the prevalence of anti-receptor autoantibodies in the sera of patients with dilated cardiomyopathy (DCM), we attempted to detect autoantibodies against a series of G-protein-coupled cardiovascular receptors in a well-defined population of DCM patients from Japan. Peptides corresponding to the sequences of the second extracellular loops of the human beta 1 and beta 2 adrenoceptors, alpha 1 adrenoceptors, M2 muscarinic acetylcholine receptors and angiotensin II-1 (AT1) receptors were used as antigens in an enzyme immunoassay to screen the sera from patients with DCM (n = 28). Nine sera from patients with DCM (32%) and 2 sera from healthy subjects (9%) recognized the beta 1 adrenoceptor peptide. Ten sera from patients (36%) and 3 sera from healthy subjects (13%) recognized the M2 receptor peptide. Thirty-six per cent of the patients with autoantibody against the beta 1 adrenoceptor peptide. Ten sera from patients (36%) and 3 sera from healthy subjects (13%) recognized the M2 receptor peptide. Thirty-six per cent of the patients with autoantibody against the beta 1 adrenoceptor had autoantibody against the M2 receptor. However, no significantly high frequencies of autoantibodies against the beta 2 adrenoceptor, alpha 1 adrenoceptor and AT1 receptor were found in DCM patients. Our results demonstrate that a subgroup of patients with DCM have a specific spectrum of autoantibodies which are specifically directed against the second extracellular loops of the beta 1 adrenoceptors and M2 muscarinic receptors rather than other cardiovascular receptors.

Adult↗
PubMed1994

Urinary carnitine excretion in patients with heart failure.

To evaluate the fatty acid metabolism in heart failure, the semiquantitative analysis of urinary free carnitine and acylcarnitine was made by fast atom bombardment mass spectrometry (FABMS) in 22 patients (mean age 67.3 years) with heart failure and 19 age-matched healthy controls (average age 60.4 years). Urinary excretion of free carnitine was 0.20 +/- 0.118 ratio/mg creatinine in the healthy controls and 1.32 +/- 1.170 ratio/mg creatinine in the patients with heart failure. The latter value was significantly higher (p < 0.01). Patients with heart failure were classified into two groups according to the urinary free carnitine concentration. One was the high excretion group (2.19 +/- 0.102 ratio/mg creatinine, 12 cases) and the other was the low excretion group (0.37 +/- 0.212 ratio/mg creatinine, 10 cases). In the high excretion group, urinary acetylcarnitine was also increased, but no significant abnormalities were observed in the urinary organic acid profile. In the high group, 1 patient was classified as NYHA class III and 11 as NYHA class IV. Four patients died in the hospital. In the low excretion group, five patients were classified as NYHA class III and five as NYHA class IV. Only one patient died in the hospital. In the high group, patients with severe and prolonged heart failure tended to maintain higher values of urinary free carnitine. We could not find any abnormalities in fatty acid metabolism in patients with heart failure, but it is suspected that the patients who excrete large amounts of free carnitine into the urine, namely the patients with severe heart failure, have some possibility of carnitine deficiency.

Acetylcarnitine↗
PubMed1994

Estimation of mitral valve area in patients with mitral stenosis by the flow convergence region method: selection of aliasing velocity.

OBJECTIVES: We attempted to determine the most suitable aliasing velocity for applying the hemispheric flow convergence equation to calculate the mitral valve area in mitral stenosis using a continuity equation. BACKGROUND: The flow convergence region method has been used for calculating mitral valve area in patients with mitral stenosis. However, the effect of varying aliasing velocity on the accuracy of this method has not been investigated fully. METHODS: We studied 42 patients with mitral stenosis using imaging and Doppler echocardiography. Aliasing velocities of 17, 21, 28, 34, 40 and 45 cm/s were used. The transmitral maximal flow rate (Q [ml/s]) was calculated using the hemispheric flow convergence equation Q = 2 x pi x R2 x AV x alpha/180, where R (cm) is the maximal radius of the flow convergence region, AV is the aliasing velocity, and alpha/180 is a factor accounting for the inflow angle (alpha). Mitral valve area (A [cm2]) was calculated according to the continuity equation A = Q/V, where V (cm/s) is the peak transmitral velocity by the continuous wave Doppler method. RESULTS: Mitral valve area was progressively underestimated with increasing aliasing velocity. The actual and percent differences noted between the mitral valve area by the flow convergence region method and that by two-dimensional echocardiographic planimetry were -0.06 +/- 0.23 cm2 (mean +/- SD) and 0.09 +/- 15.7% at an aliasing velocity of 21 cm/s, increasing gradually with increasing aliasing velocity, and were -1.24 +/- 0.9 cm2 and -72.56 +/- 16.4% at an aliasing velocity of 45 cm/s. Mitral valve areas estimated by the flow convergence region method at an aliasing velocity of 21 cm/s in 11 patients with associated > 2+ mitral regurgitation (2.12 +/- 1.17 cm2) and 8 with associated > 2+ aortic regurgitation (1.28 +/- 0.71 cm2) were not significantly different using planimetry (2.24 +/- 1.39 cm2, p > 0.05 and 1.27 +/- 0.74 cm2, p > 0.05, respectively) but were significantly different by the pressure half-time method (1.59 +/- 1.12 cm2, p < 0.001 and 1.63 +/- 0.93 cm2, p < 0.01, respectively). CONCLUSIONS: This study indicated the most appropriate aliasing velocity for the accurate estimation of mitral valve area in patients with mitral stenosis.

Adolescent↗
PubMed1993

Quantification of coronary artery calcification using ultrafast computed tomography: reproducibility of measurements.

BACKGROUND: Ultrafast computed tomography (CT) is a non-invasive method of visualizing and quantifying coronary artery calcification; its reproducibility, however, has not been fully elucidated. METHODS: To assess intra-observer, inter-observer, and inter-study reproducibility, 75 consecutive patients (51 men and 24 women) were studied. CT images were obtained using the volume mode of ultrafast CT (Imatron C-100). A total coronary calcification score (TCS) was calculated from the lesion area (> or = 2 pixels) and its peak CT density (> or = 130 HU). RESULTS: There was no intra-observer variability in two experienced observers. The TCS provided by these observers disagreed in 18 out of 75 (24%) cases, and the differences were -5.1 +/- 53 (mean +/- SD) for TCS and 0.014 +/- 0.13 for In(1 + TCS). They resulted from either 10 incorrect identifications of small coronary branches, or eight variations in determination of the ostial margin. The former was much smaller than the latter in TCS (0.66 +/- 3.0 and -48 +/- 165, respectively), but both were quite similar in In(1 + TCS) (0.082 +/- 0.31, 0.017 +/- 0.22, respectively). Between two scans, 50 out of 75 patients (67%) had different TCS values. The mean differences (95% confidence interval) were 1.8 +/- 106 (-210 to 214) in TCS, and -0.015 +/- 0.46 (-0.94 to 0.91) in In(1 + TCS). Because the differences increased with the mean values, the determination of TCS assumed a constant variance with increasing mean level. A comparison of scan images indicated that partial volume effects were responsible for this constant variance. CONCLUSION: Partial volume effects play a key role in producing the variability of TCS determination, and log transformation should be used to interpret TCS values. Thus, for clinical purposes, we recommend that two scans be performed in rapid succession, and that the average of these two scans be used to determine TCS.

Adolescent↗
PubMed1993

[Two cases of rupture of intraaortic balloon].

We reported two cases of rupture of intraaortic balloon (IAB). The most likely cause appears to be the rupture of IAB membrane against a calcific atherosclerotic aortic plaque. When the IAB ruptures by contact of calcific lesions in aorta, the leak detection of device of intraaortic balloon pumping is useless to diagnose this rupture. Therefore, the rupture of IAB through a pin hole is diagnosed by the transient presence of blood in the tube connecting the balloon. It is recommended that the balloon immediately should be removed at the transient presence of blood in the connecting tube.

Aged↗
PubMed1993

[A successful surgical repair for all right pulmonary venous return and intact atrial septum associated with patent left superior vena cava].

A successful repair of total right pulmonary venous return and intact atrial septum associated with patent left superior vena cava (PLSVC) is reported. A 31-year-old women was admitted for evaluation of heart failure. A heart murmur had been detected since her childhood without any subjective symptoms. She was diagnosed as partial anomalous venous return of all right pulmonary vein and intact atrial septum (IAS) associated with PLSVC by cardiac catheterization. Operative findings revealed that all right pulmonary vein connected to right atrium (RA) and superior vena cava (SVC), PLSVC drained into coronary sinous (CS), therefore RA, right ventricle and CS were enlarged, but SVC was small due to PLSVC. Through large incision from RA to SVC, atrial septum was opened 30 mm in diameter. Internal conduit using pericardial patch was made in order to drain anomalous pulmonary venous blood into left atrium through the ASD. Finally, SVC and RA were reconstructed by pericardial patch for prevention of conduit obstruction. One month after operation, no stenosis of SVC and right pulmonary vein was evidenced by cardiac catheterization and all through the postoperative course, arrhythmias did not detected. She was discharged with uneventful postoperative course.

Adult↗
PubMed1991

Effects of some radical scavengers on reperfusion-induced arrhythmias in the canine heart.

In this study, using electron spin resonance (ESR), we investigated the relation at the time of reperfusion between free radicals originating from the mitochondria of the canine myocardium and arrhythmias induced by reperfusion as well as the effect of radical scavengers on both. The left anterior descending artery was ligated just below the first diagonal branch and then reperfused for 10 minutes in 48 adult mongrel dogs. The dogs were divided into six groups consisting of: 1) control group administered no radical scavengers (n = 8), 2) SOD group (n = 6) receiving superoxide dismutase (15,000 U/kg), 3) SOD + CAT group (n = 6) receiving SOD (15,000 U/kg) and catalase (45,000 U/kg), 4) L-SOD group (n = 6) receiving liposomal-encapsulated SOD (30,000 U/kg), 5) CV-3611 (2-O-octadecylascorbic acid) group (n = 8) receiving CV-3611 (10 mg/kg), and 6) CoQ10 group (n = 6) receiving coenzyme Q10 (10 mg/kg). SOD, SOD + CAT, L-SOD, CV-3611, and CoQ10 were administered into the left atrium prior to reperfusion. The second lead of the electrocardiogram was continuously monitored during the experiment. The following results were obtained. 1) The relative intensity (RI) of the electron spin resonance signal of the mitochondria of the reperfused portion of the myocardium was smaller (p less than 0.025) in the SOD, SOD + CAT, L-SOD, CoQ10 groups (1.08 +/- 0.36, 0.92 +/- 0.19, 0.91 +/- 0.11, and 0.81 +/- 0.09, respectively) than in the control group (1.70 +/- 0.20).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Clinical efficacy of PTCA and identification of restenosis: evaluation by serial body surface potential mapping.

We used serial body surface potential mapping (BSPM) with the departure map technique to evaluate the clinical efficacy of percutaneous transluminal coronary angioplasty (PTCA) in various pathophysiologic stages of coronary artery disease, and to detect restenosis. The BSPM was performed prior to, 1 week after, and 1 month after PTCA. A follow-up coronary angiography was performed 3 to 6 months after PTCA, and BSPM was also performed at the same time. The results of BSPM were compared with those of thallium-201 single-photon emission computed tomography (Tl-201 SPECT) and radionuclide ventriculography. After PTCA, BSPM showed a significant reduction in the departure area, the Tl-201 SPECT also showed a significant reduction in the extent and severity scores, and the left ventricular ejection fraction improved significantly. In the cases with restenosis, the departure area, which had decreased in size after PTCA, showed an increase in size. After successful re-PTCA, the size of the departure area again became smaller. We concluded that BSPM, which is a simple, noninvasive, and inexpensive method, is useful in the evaluation of the clinical efficacy of PTCA and in the detection of restenosis after successful PTCA.

Adult↗
PubMed1991

Disappearance of mitral valve regurgitation after successful percutaneous transluminal coronary angioplasty.

Percutaneous transluminal coronary angioplasty has been reported to improve several clinical parameters. Functional papillary muscle dysfunction, which is also known to induce mitral valve regurgitation, is reversible after revascularization. We described a patient, with a 95% stenosis of proximal right coronary artery, whose mitral valve regurgitation disappeared after successful percutaneous transluminal coronary angioplasty.

Aged↗
PubMed1991

[Evaluation of healing process in myocardial infarction by the time course of serum myosin light chain I: the effects of early reperfusion].

The effects of early reperfusion on the infarct area were evaluated by measuring the plasma creatine phosphokinase (CPK) activity and myosin light chain I (LCI) in 30 patients with acute myocardial infarction. Twenty of these patients underwent coronary angiography, of whom 9 had reperfusion with successful intracoronary thrombolysis, which revealed significant correlations between peak values of LCI and peak values of CPK or CPK-MB activity (r = 0.775, p < 0.01 or r = 0.783, p < 0.01). Similarly, peak value of LCI correlated with left ventricular ejection fraction (r = -0.729, p < 0.01) and the infarct size which was estimated according to the extent and severity scores measured by Tl-201 myocardial SPECT (vs extent score, r = 0.439, p < 0.05; vs severity score, r = 0.429, p < 0.05). The time activity curves of plasma CPK activity and LCI differed in patients with and without reperfusion; in the former, mean peak values of CPK activity and LCI were 1,170 +/- 321 U/L (mean +/- SD) and 10.7 +/- 3.5 ng/ml, respectively, while in the latter, they were 5,430 +/- 3,315 U/L and 25.2 +/- 12.9 ng/ml, respectively. The times to peak values of LCI and CPK did not differ between these 2 patient groups. We concluded that the early reperfusion suppresses the progressive extension of irreversible injury in the infarct area and significantly diminishes the infarct size.

Aged↗