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Biomedical subjects

T Iwasaka

Publications and source records attributed to T Iwasaka.

At least 217 records · Page 12Linked to original sources
PubMed1992

Detection of Epstein-Barr virus DNA from a lymphoma-like lesion of the uterine cervix.

The case of a 60-year-old woman in whom a lymphoma-like lesion of the cervix was found during an episode of silent Epstein-Barr virus (EBV) infection is presented. Fractional curettage was performed because of abnormal endometrial smear. The endocervical curettage specimens were diagnosed as highly suggestive of malignant lymphoma, but microscopic examination of a subsequent hysterectomy specimen revealed a benign lymphoid hyperplasia. Those were retrospectively interpreted as a lymphoma-like lesion of the cervix. In the absence of clinical symptoms of infectious mononucleosis, the results of serologic tests for EBV revealed an active EBV infection. EBV DNA was demonstrated in nuclei of large lymphoid cells in endocervical curettage specimens by in situ hybridization. She is alive and well 32 months postoperatively. When female patients with lymphoma-like lesions of the lower genital tract are encountered, examinations for EBV are recommended.

Cervix Uteri↗
PubMed1992

Detection of human papillomavirus genome and analysis of expression of c-myc and Ha-ras oncogenes in invasive cervical carcinomas.

Invasive carcinomas of the uterine cervix of 38 patients were examined for the presence of human papillomavirus (HPV) genomes and for the state of the c-myc and Ha-ras oncogenes. A combination of Southern blot hybridization and polymerase chain reaction revealed the presence of the genome of HPV type 16 in 17 tumors (45%), that of HPV type 18 in 3 tumors (8%), and that of unknown types in 16 others (42%), while no viral DNA sequences were detected in 2 tumors. Of the 38 tumors, c-myc amplification was found in only 1 tumor, while there was no Ha-ras amplification. Overexpression of the c-myc gene was observed in 15 (44%) of the 34 tumors analyzed, while there was no overexpression of Ha-ras. Of the 23 squamous cell carcinomas analyzed, relapse-free rates at 24 months were 55% in tumors with c-myc overexpression and 100% in case of tumors with no c-myc overexpression, respectively. The results suggest the possibility that activation of the c-myc oncogene is involved in tumor progression.

Base Sequence↗
PubMed1992

Difference in the residual left ventricular pump function between anterior and inferior myocardial infarctions.

To evaluate the left ventricular regional ejection fraction (EF) of noninfarcted area in relation to the left ventricular end-diastolic volume (EDV) in patients with recent myocardial infarction (MI), 75 patients with Q-wave MI (anterior: 51 patients; inferior; 24 patients) were studied. The regional EF of noninfarcted area was obtained by radionuclide angiocardiography 4 weeks after the onset of MI and was used to estimate the left ventricular regional function of the noninfarcted area. Peak creatine kinase and QRS scores were not significantly different between anterior and inferior MI in each left ventricular EDV (EDV < or = 100, 101-139 and > or = 140 ml). Global EF and regional EF of noninfarcted area in anterior MI with left ventricular EDV > or = 140 ml was significantly lower than in those with EDV < or = 139 ml (p < 0.01), whereas there were no significant differences in global EF and regional EF of noninfarcted area in the three groups of left ventricular EDV in inferior MI. Thus, the effect of left ventricular EDV on regional EF of noninfarcted area and on the total cardiac performance was more important in anterior than in inferior MI, because a similar degree of left ventricular dilatation resulted in more severe derangements after anterior MI.

Adult↗
PubMed1992

Diastolic time and left ventricular performance during one- and two-handed weight holding.

To evaluate the difference in DT and systolic time intervals during one-handed and two-handed weight holding with the same total load, the DT-heart rate relationship was studied in 12 patients and ten normal volunteers. Heart rate, blood pressure, and pressure-rate product were significantly higher in one-handed compared with two-handed weight-holding exercise in patients with MI. Although there were no significant differences in QS2 and DT between the two types of weight-holding exercise in normal volunteers, QS2 was significantly longer and DT was significantly shorter in one-handed compared with two-handed weight-holding exercise in patients with MI. Disproportionate shortening of DT with higher pressure-rate product during one-handed compared with two-handed weight-holding exercise can initiate an imbalance of myocardial oxygen supply and demand in patients with MI.

Analysis of Variance↗
PubMed1992

Disturbance of pulmonary gas exchange in patients with right ventricular infarction.

To evaluate the difference in pulmonary gas exchange in patients with and without right ventricular infarction, 147 consecutive patients with their first inferior wall Q-wave acute myocardial infarction were studied. Thirty-nine patients (group 1) had electrocardiographic evidence of right ventricular infarction and it was absent in 108 patients (group 2). A significantly wider alveolar arterial oxygen difference and higher roentgenographic scores were observed in group 1 compared with group 2. Although there were no significant differences in pulmonary artery wedge pressure and colloid osmotic pressure between groups 1 and 2, mean right atrial pressure was significantly higher, while cardiac output and mixed venous oxygen saturation were lower in group 1 compared with group 2. Patients in group 1 had significantly more left ventricular segments with advanced asynergy and higher incidence of proximal right coronary artery lesions than those in group 2. Thus, our data suggest that disorder of pulmonary gas exchange in patients with right ventricular infarction may be explained by increased permeability of the alveolar capillary membrane secondary to larger extent of ischemic myocardium and by hemodynamic abnormalities associated with right ventricular infarction.

Catheterization, Swan-Ganz↗
PubMed1992

Left ventricular function in myocardial infarction. Predictive value during negative low-level exercise three weeks postinfarction.

To evaluate whether the response of left ventricular pump function during low-level exercise in the early postinfarction period can anticipate its change during the first year after acute myocardial infarction (MI), global and regional ejection fractions (EF) were investigated using radionuclide angiography in 52 consecutive patients with negative predischarge exercise test. The changes in left ventricular EF and regional EF of the noninfarcted area during the early exercise test had a good linear relation with the changes during the first year after MI (r = 0.86, p less than 0.001 and r = 0.81, p less than 0.001, respectively). Our results indicate that the mobilization of the Frank-Starling mechanism and myocardial contractility were the important factors related to the change of left ventricular EF, and that the changes of left ventricular EF during exercise in the patient with a negative predischarge exercise test can predict the direction of change (concordant rise or fall) during the first year after MI.

Electrocardiography↗
PubMed1992

Role of platelet-activating factor in pulmonary edema after coronary ligation in dogs.

To evaluate whether PAF is related to the precipitation of pulmonary edema after myocardial ischemia, we studied the effect of a specific PAF antagonist, CV-6209, on the extravascular lung water level measured by the thermal-dye double indicator dilution method, ETV, after coronary ligation in dogs. Eight dogs served as sham control animals (group 1). The proximal left anterior descending coronary artery was ligated for 45 min in eight dogs (group 2), and the coronary artery was ligated after pretreatment with CV-6209 (1 mg/kg) in eight dogs (group 3). The ETV increased significantly after coronary ligation in groups 2 and 3. The amount of increase in ETV in group 2 was significantly larger than in group 3. Thus, CV-6209 can prevent the accumulation of extravascular lung water after coronary ligation without producing changes in pulmonary vascular dynamics, indicating that PAF may play an important role in pulmonary edema after myocardial ischemia.

Animals↗
PubMed1992

Residual left ventricular pump function after acute myocardial infarction in NIDDM patients.

OBJECTIVE: Left ventricular remodeling occurs immediately after MI, involving structural changes in noninfarcted segment. However, the residual left ventricular pump function in NIDDM patients after acute MI has not been clarified. The purpose of this study was to evaluate the difference in the process of left ventricular remodeling between NIDDM and nondiabetic patients. RESEARCH DESIGN AND METHODS: Left ventricular regional EF images obtained by radionuclide angiography were investigated in 20 NIDDM and 29 nondiabetic patients the 3rd wk after acute MI. RESULTS: Regional EF of the noninfarcted area and P/V had a significant hyperbolic relation with left ventricular EDV in both groups of patients. Despite no difference in the extent of myocardial necrosis and the number of coronary vessels diseased between NIDDM and nondiabetic patients, regional EF of the noninfarcted area and P/V were significantly lower when left ventricular EDV increased in NIDDM patients compared with nondiabetic patients. CONCLUSIONS: Pathogenetic changes of the residual myocardium associated with NIDDM may adversely influence the process of left ventricular remodeling after MI, especially in patients with increased left ventricular EDV.

Adult↗
PubMed1992

'Hit and run' oncogenesis by human papillomavirus type 18 DNA.

Transfection of an immortalized cell line (AE), derived from Syrian hamster embryo cells, with human papillomavirus type 18 (HPV 18) DNA induced morphological transformation and these transformed cells were tumorigenic in nude mice. Southern blot analysis revealed that the transfected viral DNA was retained in all the cell lines tested, however, all these transformed cells contained only less than one copy per cell of viral genome. Eleven cloned cell lines were established from a tumor cell line obtained after explantation of a tumor into a nude mouse. Two lines revealed no viral sequences by both Southern blot hybridization and polymerase chain reaction, whereas the nine others contained the remaining viral sequences. These results are highly suggestive of a 'hit and run' oncogenesis by this virus.

Animals↗
PubMed1992

[Clinical characteristics of pulmonary edema in patients with unstable angina].

To elucidate the clinical characteristics of pulmonary edema in unstable angina, 120 patients with unstable angina who admitted to the hospital within 6 hours after the onset of chest pain were studied. The criteria for the diagnosis of pulmonary edema included interstitial pulmonary edema and diffuse alveolar edema. Pulmonary edema was present in 24 patients. In these patients, the duration of chest pain was relatively longer, and the incidences of diabetes mellitus, emergency coronary revascularization and multiple-vessel coronary artery disease were higher than in those without pulmonary edema. In addition, in-hospital mortality rate in patients with pulmonary edema was higher than in those without it (21 vs 1%, p < 0.001), which is probably due to a large area of myocardial ischemia. For these patients, therefore, early diagnosis and appropriate therapy to save viable segments of the myocardium are mandatory.

Aged↗
PubMed1992

[Left ventricular systolic time intervals during paroxysmal supraventricular tachycardia: the difference between A-V nodal re-entry and A-V re-entry].

In this study, the differences in hemodynamic changes during paroxysmal supraventricular tachycardia (PSVT) between A-V nodal re-entry and A-V re-entry were evaluated. In 8 patients with A-V nodal re-entrant tachycardia and 10 with A-V re-entrant tachycardia, electrophysiological studies were performed to measure systolic time intervals (pre-ejection period: PEP, ejection time: ET, PEP/ET ratio: PEP/ET). These measurements were obtained in the control state (atrial pacing at 90/min) and during PSVT with simultaneous recordings of electrocardiogram and femoral arterial pulse tracing. During PSVT, there was no difference in the heart rate between the 2 groups, but ventriculo-atrial conduction time was shorter in A-V nodal re-entry than in A-V re-entry. There was a marked fall in the ET and an increase in PEP/ET in all the patients when PSVT was induced. PEP increased significantly in A-V nodal re-entry, but did not change in A-V re-entry. This resulted in a greater increase in the PEP/ET suggesting a greater deterioration of the hemodynamic consequences in A-V nodal re-entry than in A-V re-ent y. Thus, the hemodynamic changes of PSVT differ between these 2 types of re-entrant circuits, which are mainly influenced by the ventriculo-atrial conduction time.

Adult↗
PubMed1992

[The use of a Swan-Ganz catheter with a fast-response thermistor for the measurement of right ventricular performance during anesthetic management of pheochromocytoma].

We used a Swan-Ganz catheter with a fast-response thermistor to measure the right ventricular ejection fraction (RVEF) during the anesthetic management of two patients with epinephrine-dominant pheochromocytomas. Pre-operatively, one patient received alpha adrenergic blocking agents (prazocine, doxazocine) to control the blood pressure but the other patient did not receive any agents. In the latter patient who did not receive alpha adrenergic blocking agents, right ventricular function was depressed post-operatively in the recovery room. The importance of preoperative preparation with alpha adrenergic blocking agents was confirmed by the reductions in RVEF and RVEDVI (right ventricular end-diastolic volume index) after resection of the tumor. Not only left heart monitoring but also right heart monitoring with RVEF and RVEDVI are recommended for the proper management of a patient with pheochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1991

Age-related changes in aortic elasticity determined by gated radionuclide angiography in patients with systemic hypertension or healed myocardial infarcts and in normal subjects.

We estimated the aortic volume elasticity (Ve), an index of aortic stiffness, using gated radionuclide angiography, and investigated age-related changes in aortic elasticity in 22 normal control subjects, 30 hypertensive patients and 36 patients with old myocardial infarction. Ve elasticity was calculated noninvasively as a ratio of the pressure change (dP) and the percent volume change (dV/Vo) determined by radionuclide angiography [Ve = dP/(dV/Vo)]. dV/Vo was calculated from the maximal and minimal counts in the aortic arch [dV/Vo = (maximum - minimum)/minimum]. Ve increased significantly with age in normal control subjects (r = 0.62, p less than 0.001), hypertensive patients (r = 0.60, p less than 0.001) and patients with old infarcts (r = 0.59, p less than 0.001). The age-related increase in Ve was significantly greater in hypertensive patients, and that for patients with old myocardial infarcts tended to be greater than in control subjects. Thus, hypertension accelerates the decrease in aortic elasticity with aging. The greater decrease in aortic elasticity resulted in a significant age-related increase in pulse pressure in patients with hypertension and old myocardial infarction.

Adult↗
PubMed1991

Oxygen utilization, carbon dioxide elimination and ventilation during recovery from supine bicycle exercise 6 to 8 weeks after acute myocardial infarction.

The pattern of oxygen (O2) consumption (VO2), carbon dioxide (CO2) production (VCO2), ventilatory and metabolic responses during and in recovery from supine bicycle exercise was examined in 18 patients with recent myocardial infarction. An increase in VO2 with increasing work load was accomplished by proportional increases in both cardiac output and the arteriovenous O2 difference. During recovery, however, the arteriovenous O2 difference rapidly decreased below levels at rest, whereas VO2 and cardiac output remained elevated, indicating that VO2 during recovery further depended on relatively high cardiac output. The ratio of VCO2 to VO2 further increased after exercise, suggesting that such cardiac output contributed to the remaining high CO2 flow to the lung and therefore enhanced ventilation. Increased arterial catecholamines during exercise remained elevated for the first 5 minutes of recovery. Arterial lactate during this period continued to increase and resulted in profound metabolic acidosis, causing alveolar hyperventilation after exercise. These results suggest that during recovery from exercise, cardiopulmonary responses remain enhanced because of continuing high cardiac output, resulting in subsequent high CO2 flow to the lung and metabolic acidosis, and that this may be associated with profound fatigue or dyspnea after exercise.

Acidosis, Lactic↗