Biomedical subjects

T Iwasaka

Publications and source records attributed to T Iwasaka.

At least 199 records · Page 11Linked to original sources

PubMed1993

Precordial ST segment depression in patients with Q wave inferior myocardial infarction: role of infarction-associated pericarditis.

To examine the diagnostic significance of precordial ST segment depression in Q wave inferior myocardial infarction, 157 consecutive patients were examined carefully by means of auscultation, ECG, and two-dimensional echocardiography. Precordial ST segment depression was transient (lasting < 72 hours from the onset of myocardial infarction) in 63 patients and persistent (> or = 72 hours) in 40. Twenty-eight patients with persistent, 19 patients with transient, and 14 patients without precordial ST segment depression had advanced asynergy (akinesia or dyskinesia) in the posterior segments, whereas 13 patients with persistent, six with transient, and six without precordial ST segment depression had pericardial rub. Patients with persistent precordial ST segment depression had a significantly higher incidence of severe wall motion abnormality (p < 0.01) and inflammation (p < 0.05) of the posterior wall than the other two groups. In 5 of 40 patients with persistent ST segment depression, pericardial rub was detected in the absence of advanced asynergy in the posterior segments. Although not highly sensitive, persistent precordial ST segment depression appeared to be a fairly specific indicator (specificity 92%) of concomitant posterior involvement with severe wall motion abnormality, inflammation, or both.

Aged↗

PubMed1993

Polymerase chain reaction analysis of human papillomavirus in adenocarcinoma and adenosquamous carcinoma of the uterine cervix.

Thirty-two cervical adenocarcinomas and adenosquamous carcinomas were examined to search for human papillomaviruses (HPVs) using the polymerase chain reaction system. Human papillomavirus type 16 (HPV16) and type 18 (HPV18) deoxyribonucleic acid was detected in 22% and 16% of these carcinomas, respectively. HPV16 was the most common type in both adenocarcinoma and adenosquamous carcinoma, and the mean age of the HPV negative patients was significantly higher than that of HPV positive patients. There may be an association between HPVs and the development of certain adenocarcinomas and adenosquamous carcinomas of the cervix.

Adenocarcinoma↗

PubMed1993

Effect of sex on left ventricular pump function in patients with anterior wall myocardial infarction treated with primary angioplasty.

BACKGROUND: The prognosis of acute myocardial infarction (AMI) is distinctly worse in postmenopausal women than in age-matched men. Unstable angina before AMI is reported to protect left ventricular pump function during the left ventricular remodeling process in patients who have undergone successful percutaneous transluminal coronary angioplasty (PTCA). We postulate that left ventricular pump function may be different in postmenopausal women and age-matched men with unstable angina before AMI and successful PTCA. METHODS: Twenty-three postmenopausal women (aged 63 +/- 7 years) and 31 age-matched men (aged 65 +/- 6 years) with unstable angina before AMI and successful PTCA were investigated using radionuclide angiography in the late hospital phase. RESULTS: Global ejection fraction (EF), regional EF of the non-infarcted area, and the ratio of systemic arterial systolic blood pressure to left ventricular end-systolic volume (P:V ratio) were lower in women compared with those in men. Global EF, regional EF of the non-infarcted area, and the P:V ratio in women with left ventricular end-diastolic volume (EDV) > or = 140 ml were significantly lower than in those with a left ventricular EDV of less than 140 ml, but no significant differences were noted in these indexes with regard to left ventricular EDV in men. CONCLUSION: Sex may play an important role in the left ventricular remodeling process in postmenopausal women, especially those with a dilated left ventricle.

Aged↗

PubMed1993

Effect of subadipose tissue on the variables of signal-averaged electrocardiograms in healthy subjects.

Ventricular late potentials are obtained by signal averaging of surface electrocardiograms. Late potentials have been reported to be affected by body size or left ventricular mass. However, the effect of subadipose tissue, which is known to influence QRS amplitudes of surface ECG, on the variables of late potentials has not been evaluated. The relationships between the variables of late potentials and various obesity indices were assessed in 45 men, aged 24-38 years, without structural heart disease and bundle branch blocks. QRS duration, root mean square voltage in the last 40 ms and low-amplitude signals < 40 microV were obtained by signal-averaged ECG. Left ventricular mass was determined by echocardiography. QRS duration and root mean square voltage had no correlation with body height, weight, body mass index, sum of skin folds (triceps and subscapular) or left ventricular mass. Positive linear correlations were found between low-amplitude signals and weight (r = 0.48, p < 0.002) body mass index (r = 0.54, p < 0.002), sum of skin folds (r = 0.57, p < 0.002), percent body mass index (r = 0.54, p < 0.002). Subadipose tissue may shift the onset of the 40-microV point of low-amplitude signals to the left with a consequent prolongation of low-amplitude signals by attenuation of the QRS complex. These data suggest that the use of low-amplitude signals alone or as a combination in an obese population for the definition of positive late potentials is inappropriate. The low-amplitude signal has to be used with caution in obese patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

PubMed1993

Increase in left ventricular ejection rate during recovery from exercise in patients with myocardial infarction.

Changes in left ventricular (LV) ejection rate were evaluated during supine bicycle exercise and recovery in 12 patients with anterior myocardial infarction. Pulmonary artery wedge pressure (34 +/- 9 to 14 +/- 5 mm Hg) and plasma norepinephrine level decreased at 2 min recovery from peak exercise, whereas plasma lactate tended to increase. As a result, LV ejection rate reached the highest value at 2 min of recovery. Thus, both cardiac (optimal filling pressure) and peripheral factors (reduced vascular resistance) caused the increase in LV ejection rate at early recovery.

Acid-Base Equilibrium↗

PubMed1993

Left ventricular function during exercise after aortic valve replacement.

To evaluate the difference in left ventricular function during exercise after successful aortic valve replacement, left ventricular function was investigated using radionuclide angiography in 12 patients with normal resting left ventricular systolic function. Patients were divided into two groups: Group 1 was comprised of 5 patients after aortic valve replacement for aortic stenosis and group 2 was comprised of 7 patients for aortic insufficiency. Left ventricular ejection fraction increased significantly during exercise in both groups. The increase in systolic arterial pressure to left ventricular end-systolic volume was significantly larger in group 1 than group 2, whereas the increase in left ventricular end-diastolic volume was significantly larger in group 2 than group 1. Thus, increase in left ventricular contractility played an important role in regulating increased left ventricular ejection fraction during exercise in patients with aortic prostheses for aortic stenosis, whereas increase in left ventricular end-diastolic volume played an important role in patients with aortic prostheses for aortic insufficiency.

Adult↗

PubMed1993

Effect of body characteristics on the variables of signal-averaged electrocardiogram in healthy teenage subjects.

Ventricular late potentials are obtained by signal-averaged surface electrocardiography. Late potentials have been reported to be affected by body characteristics or left ventricular mass. To evaluate late potentials in relation to body characteristics, 52 healthy Japanese young volunteers (21 girls, 31 boys) aged 15-16 years were studied. QRS duration in men was significantly longer than in women. There were no significant differences in low-amplitude signal and root mean square voltage between women and men. When relations between signal-averaged electrocardiographic parameters and body characteristics were examined, QRS duration had positive linear correlations with weight and body mass index. The slope of QRS duration and weight relation, and QRS duration and body mass index relation was significantly steeper in men compared to those in women; a prolongation of QRS duration in men compared to women as weight and body mass index increased. Our results indicated that QRS duration in teenage healthy subjects should be used with caution because it is affected by gender.

Adolescent↗

PubMed1993

Ventriculoarterial coupling during low-level exercise testing after myocardial infarction.

To evaluate the change of ventriculoarterial coupling during low-level exercise in patients after myocardial infarction, the ratio of systolic blood pressure to left ventricular end-systolic volume (P/V ratio) and the ratio of systolic blood pressure to stroke volume (effective arterial elastance) were investigated using radionuclide angiography in 73 consecutive patients with a negative predischarge exercise test. The patients were divided into three groups according to their resting left ventricular ejection fraction: group A (n = 12) > or = 60%; group B (n = 32) 41-59%; group C (n = 29) < or = 40%. The ejection fraction increased significantly during exercise in all three groups. There was no significant difference in the change of the P/V ratio during exercise between groups A and B, but it was significantly smaller in group C. The effective arterial elastance increased during exercise in group A, did not change in group B, and decreased in group C. Thus, the augmentation of myocardial contractility was an important factor related to the increase in ejection fraction during exercise in patients with normal or slightly reduced cardiac function, whereas the decrease in effective arterial elastance was important in patients with poor cardiac function.

Adult↗

PubMed1993

Left ventricular diastolic filling properties in diabetic patients during isometric exercise.

Left ventricular diastolic filling properties during isometric handgrip exercise were measured by pulsed Doppler echocardiography in 33 noninsulin-dependent diabetic patients with a normal ejection fraction and 15 control subjects. Diabetic patients were subdivided into two groups according to their resting left ventricular filling pattern (A/E): 18 patients were in group DM-1 (A/E < or = 1.1) and 15 patients were in group DM-2 (A/E > 1.1). At rest, A/E ratio and A wave were higher, and deceleration half-time was longer in group DM-2 than in normal subjects and group DM-1, but there was no significant difference between normal subjects and group DM-1. The A/E ratio increased significantly in all three groups during isometric handgrip exercise. However, the change in A/E from rest to peak exercise in group DM-1 (0.29 +/- 0.20) was significantly greater than in normal subjects (0.09 +/- 0.07). These results suggest that diabetes mellitus patients with normal resting left ventricular (LV) filling pattern (group DM-1) had LV diastolic filling abnormalities with isometric handgrip exercise. Doppler echocardiography with isometric handgrip exercise is useful in identifying underlying left ventricular diastolic dysfunction in diabetic patients.

Diabetes Mellitus, Type 2↗

PubMed1993

Effect of the leukotriene receptor antagonist ONO-1078 on extravascular lung water after coronary ligation in dogs.

To determine whether or not leukotrienes are associated with pulmonary edema after coronary ligation in dogs, we studied the effects of a specific leukotriene C4/D4 antagonist, ONO-1078, on extravascular lung water, as measured by the thermal-dye double indicator dilution method (Extravascular thermal volume, ETV). Six dogs served as a sham control (group 1). The proximal left anterior descending coronary artery was ligated for 45 min in 6 dogs (group 2), and in 6 others the coronary artery was ligated after pretreatment with ONO-1078 (1 mu/kg/min) (group 3). ETV and pulmonary arterial pressure were measured at control and 45 min after coronary ligation. In group 1, no significant change was found in ETV. Although there was no significant increase in pulmonary arterial pressure after coronary ligation, ETV significantly increased in groups 2 and 3. ETV increased more in groups 2 and 3 than in group 1, but there was no significant difference between groups 2 and 3. Thus, ONO-1078 did not effectively prevent the accumulation of extravascular lung water after coronary ligation, indicating that leukotrienes are not important mediators of pulmonary edema after myocardial ischemia.

Animals↗

PubMed1993

Overshoot in mixed venous oxygen saturation during recovery from supine bicycle exercise in patients with recent myocardial infarction.

During recovery from dynamic exercise, systemic oxygen extraction rapidly decreases below the resting level in patients with heart failure, which leads to a subsequent increase in mixed venous oxygen saturation (SvO2) above its resting value (postexercise SvO2 overshoot). To evaluate the pathophysiologic basis of this phenomenon, postexercise SvO2 overshoot was evaluated in relation to hemodynamic, metabolic, and neurohumoral responses during recovery from maximal supine bicycle exercise in 22 patients with recent myocardial infarction. Postexercise SvO2 overshoot closely correlated with increased systemic vascular resistance (r = 0.79, p < 0.001) and reduced cardiac output (r = -0.74, p < 0.001), suggesting that SvO2 overshoot is primarily due to increased peripheral arteriovenous shunting caused by an enhanced peripheral vasoconstriction in the setting of reduced cardiac output. Postexercise SvO2 overshoot and systemic vascular resistance were significantly higher and cardiac output was significantly lower in New York Heart Association functional class 3 and 4 (8 patients) compared with class 1 and 2 (14 patients), whereas systemic arterial blood pressure was maintained at normal levels in both groups. Thus, postexercise SvO2 overshoot and, hence, decreased systemic oxygen extraction during recovery represent a compensatory response of an enhanced peripheral vascular tone that maintains systemic arterial blood pressure in the setting of reduced cardiac output by linking central and peripheral blood flow.

Adult↗

PubMed1993

Natural history of left ventricular function in patients with uncomplicated acute myocardial infarction.

To investigate the serial changes of the infarcted and the noninfarcted areas, first-pass radionuclide angiocardiography was performed in 16 patients with uncomplicated anterior myocardial infarction (MI) at four weeks, one year, and two years after the onset of MI. Global ejection fraction (EF) and regional EF of the infarcted area improved significantly from four weeks to one year after MI (from 39 +/- 16 to 44 +/- 16 percent, 23 +/- 3 to 29 +/- 5 percent, both p < 0.01), but did not change from one year to two years after MI. Regional EF of the noninfarcted area and left ventricular end-diastolic and end-systolic volume did not change during the study period. There was a significant relation in the direction of the changes of global EF and regional EF of the infarcted area during the first year after MI, whereas no relation was observed between the changes of global EF and regional EF of the noninfarcted area. A greater improvement in regional EF of the infarcted area was observed in seven patients who had spontaneous recanalization compared with nine patients with totally occluded coronary arteries. Thus, a significant improvement in cardiac function, mainly due to the increase in regional EF of the infarcted area, was observed during the first year after MI, which was related to patency of coronary artery.

Adult↗

PubMed1993

Pulmonary edema after anteroseptal acute myocardial infarction.

To evaluate the clinical characteristics of patients with anteroseptal myocardial infarction (MI) initially presenting with pulmonary edema, we analyzed 58 patients with anteroseptal MI who underwent emergency coronary arteriography that revealed single-vessel disease of the left anterior descending coronary artery. Of the 58 patients, pulmonary edema was observed in 24 patients (group A) and was absent in 34 patients (group B). Pulmonary capillary wedge pressure was significantly higher, and cardiac output was significantly lower in group A. The site of coronary stenosis, maximum serum creatinine kinase value, and wall motion point score did not differ between the two groups. However, the incidence of previous hypertension and posterior wall thickness > or = 11 mm was significantly higher in group A than in group B (p < 0.001 and p < 0.05, respectively). Thus, impaired left ventricular diastolic filling in the non-MI segments due to higher incidence of hypertension and left ventricular hypertrophy was considered to be the possible cause of pulmonary edema.

Cardiac Output↗

PubMed1993

Clinical significance of pericardial effusion associated with pericarditis in acute Q-wave anterior myocardial infarction.

To elucidate the incidence and clinical factors related to the occurrence of pericardial effusion in infarction-associated pericarditis, 303 consecutive patients with their first Q-wave anterior myocardial infarction were examined carefully by means of auscultation, echocardiography, chest radiography, and hemodynamic monitoring. During the first 3 days, a pericardial rub was detected in 65 patients and was absent in 238 patients. Among the 65 patients with pericardial rub, pericardial effusion was present in 27 patients (group 1) and was absent in 38 patients (group 2). Although there were no significant differences in cardiac output, pulmonary artery wedge pressure and right atrial pressure between the two groups, patients in group 1 had significantly more left ventricular segments with advanced asynergy and higher radiographic scores (diffuse interstitial infiltrate or alveolar infiltrate) compared with those in group 2. Thus, pericardial effusion and increased extravascular lung water in infarction-associated pericarditis were not caused by left ventricular failure but by other mechanisms reflecting a larger infarct.

Electrocardiography↗

PubMed1993

Human papillomavirus 16 and 18 DNA can solely induce oncogenic transformation of mammalian cells in primary culture.

To compare the tumorigenic activity of HPV 6, 11, 16, and 18 DNA in mammalian cells in primary culture, HPV DNAs were transfected to Syrian hamster embryo (SHE) cells. Morphologically transformed foci were observed in all the HPV DNA-transfected cultures and cells propagated from these foci were immortalized. All these cell lines at early passages were not tumorigenic in nude mice. However, a cell line derived from HPV 16 transfection became tumorigenic after 25 passages and a cell line derived from HPV 18 transfection also revealed tumorigenicity after 48 passages. Overexpression of the Ha-ras proto-oncogene occurred in these transformed cell lines. No tumorigenic activity was observed in HPV 6 and HPV 11-transfected cell lines. All these observations suggest that HPVs 16 and 18 have a higher transforming potential than do HPVs 6 and 11 and can solely induce tumorigenic transformation of cells in primary cultures, with continuous passage.

Animals↗

PubMed1993

[Gadolinium-DTPA magnetic resonance imaging in the diagnosis of left atrial myxoma in the elderly].

A 85-year-old woman consulted our hospital with general fatigue, palpitation and chest discomfort changing with different postures. Her electrocardiogram showed sinus tachycardia, atrial premature beats and left atrial overload. 53% cardiothoracic ratio, slightly protruding third arch of the cardiac silhouette and dilated pulmonary artery were seen on the chest X-ray. Two dimensional echocardiography revealed a mass in the left atrium although the quality of echocardiography was suboptimal due to her thoracic deformity. There was no uptake of T1-201 or Ga-67 by the mass. The four-chamber view of Tc-99m ECG-gated SPECT radionuclide angiocardiography showed a filling defect in the left atrium. The T1 weighted magnetic resonance imaging revealed a left atrial mass with relatively low signal intensity. After intravenous injection of Gadolinium-DTPA the signal intensity of the mass increased significantly and the contrast of the mass was improved. The size of the mass was 4 x 4 x 3 cm with a stalk connecting to the interatrial septum. These findings were compatible with left atrial myxoma. Gadolinium-DTPA magnetic resonance imaging is useful in diagnosing left atrial myxoma because it provides information on the size, anatomical location, relationship with other cardiovascular structures and even the characteristics of the mass.

Aged↗

PubMed1993

Local immune response in persistent cervical dysplasia.

OBJECTIVE: To investigate the differences in local immune response between persistent and regressive cervical dysplasia. METHODS: We conducted a quantitative study of Langerhans cells, pan-T cells, and helper-inducer T cells in the subepithelial connective tissue using immunohistochemical techniques with S-100 protein antibody, UCHL1, and OPD4, respectively, in 52 paraffin sections. The subjects were patients with persistent cervical dysplasia and a comparable control group of 46 patients with regressive dysplasia. RESULTS: In the subepithelial stroma, the mean (+/- standard deviation) numbers of S-100- and OPD4-positive cells in the persistent group were 8.6 +/- 8.1 and 84.6 +/- 66.3, respectively, compared with 15.1 +/- 9.4 and 147.0 +/- 67.7, respectively, in the regression group. These data demonstrate a significant reduction of Langerhans cells and helper-inducer T cells (P < .0002 and P < .0001, respectively) with persistent dysplasia. CONCLUSION: The decreased numbers of S-100-positive Langerhans cells and helper-inducer T cells in persistent dysplasia compared to those of regressive dysplasia strongly support a decreased local immune response in persistent cervical dysplasia.

Adult↗

PubMed1992

Clinical significance of serum colloid osmotic pressure in relation to pulmonary edema and coronary instability in patients with unstable angina.

Several investigators demonstrated that severe reduction of colloid osmotic pressure (COP) predicts a fatal outcome in patients with cardiopulmonary failure. To evaluate the clinical significance of COP in relation to pulmonary edema, we studied 117 patients with unstable angina admitted in the hospital within 24 h after the chest pain. The mean COP of all 117 patients was 24.8 +/- 3.7 mmHg. COP was significantly lower in patients with pulmonary edema, according to the chest x-ray findings, compared with the patients without it. Among 26 patients with emergency coronary arteriography, a fairly good correlation was observed between coronary jeopardy score and COP (r = -0.57, p less than 0.005). Furthermore, COP in patients who survived 26 months after the hospital discharge was significantly higher than that of the nonsurvivors. Thus, measurement of COP is advised for monitoring patients with unstable angina.

Angina, Unstable↗