A case of Takayasu's disease with ruptured thoracoabdominal aneurysm.
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Adult↗
Biomedical subjects
T Ban
Publications and source records attributed to T Ban.
Effects of AFD-21, a new class I antiarrhythmic agent, and AFD-19, its active metabolite, on the maximal rate of rise of action potentials in guinea pig papillary muscles: dependence on time, voltage, and action potential duration.
Effects of AFD-21 and AFD-19 (a new class I antiarrhythmic agent and its active metabolite, respectively) on the maximal rate of rise (Vmax) of action potentials (APs) were studied in guinea pig papillary muscles with special reference to their time, voltage, and action potential duration (APD) dependence. Both AFD-21 and AFD-19 (2-10 microM) reduced Vmax in a concentration-dependent manner without affecting the resting potential, APD, and effective refractory period. Both agents (5 microM) shifted the normalized Vmax resting potential curve (examined at 1 Hz) in the hyperpolarizing direction by 4-7 mV (voltage dependence). In addition, both agents (5 microM): a) caused a frequency-dependent reduction of Vmax at 0.25-3 Hz; b) developed a use-dependent (1 Hz) reduction of Vmax with an onset time constant of 1-3 s; and c) slowed the recovery process of Vmax, whose resultant recovery time constant was 2-3 s (time dependence). Nicorandil (1 mM), which shortens APD to about 25% of control, antagonized the AFD-21-induced time-dependent reductions of Vmax but not the AFD-19-induced reductions (APD dependence). These results suggest that the effects of AFD-21 on Vmax are APD dependent but those of AFD-19 are not, and thereby that AFD-21 and AFD-19 preferentially block inactivated and open sodium channels, respectively. The present findings are discussed from the viewpoint of the modulated or the guarded receptor hypothesis.
Action Potentials↗
Effects of coronary artery bypass surgery on regions showing persistent defects in thallium myocardial images.
The indications for revascularization surgery and its effects on myocardial regions showing persistent defects in thallium myocardial images are controversial. The effects of aortocoronary bypass surgery on myocardial perfusion and wall motion in the regions with persistent defects were evaluated in 47 patients with thallium-201 single photon emission computed tomography and left ventriculography. In areas showing persistent thallium defects preoperatively the rate of improvement of perfusion was only 24% by postoperative thallium imaging, and 57% by wall motion analysis. These results were significantly inferior to those of regions with transient defects, which were 84% and 82%, respectively. A persistent defect may not be a definitive marker of a non-viable scar, but the results of surgery on such regions were unsatisfactory. It is concluded, therefore, that revascuralization surgery in regions with persistent defects is not always recommended and that the indications for surgery should be individually determined with operative risk balanced against benefits.
Adult↗
Value of stress thallium-201 emission tomography for predicting improvement after coronary bypass grafting and assessing graft patency.
To examine the value of stress and redistribution thallium-201 single photon emission computed tomography (SPECT) for predicting improvement after coronary artery bypass grafting (CABG) and for assessing graft patency, 17 patients underwent SPECT before and after CABG. Preoperatively, 16 patients (94%) showed reversible ischemia with redistribution, and defect score decreased from 16.4 +/- 7.6 to 8.3 +/- 5.8 (p less than 0.001) on 2 hour delayed images. Stress electrocardiography was positive in 15 cases (88%). The stress defect score was reduced postoperatively (7.8 +/- 6.3) as compared to the preoperative score (16.4 +/- 7.6) (p less than 0.001). Postoperatively, 7 cases (41%) showed reversible ischemia and the defect score decreased from 11.3 +/- 6.5 to 6.1 +/- 4.7 (p less than 0.05), while 4 cases (23.5%) showed positive stress electrocardiograms (ECG). Resting left ventricular (LV) ejection fraction (EF) improved in 6 cases (48.3 +/- 5.4% preoperatively to 56.8 +/- 7.4% postoperatively, p less than 0.05) and showed a reduction in 11 (58.2 +/- 10.5% to 47.5 +/- 9.4%, p less than 0.01). Grafts were occluded in 6 cases, and redistribution was evident on the delayed thallium images in all cases (100%), while stress ECG was positive in only 3 (50%). Thus, stress and redistribution SPECT is valuable for identifying patients who will improve after surgery and assessing graft patency more accurately than stress ECG. Resting LVEF was less useful for assessing improvement in LV function.
Adult↗
[Severe postoperative pulmonary hypertensive crisis in a case of ventricular septal defect with Down's syndrome].
We encountered the episode of severe postoperative pulmonary hypertensive crisis in a case of ventricular septal defect with Down's syndrome. A 1 year 11 month old female with ventricular septal defect and pulmonary hypertension underwent open heart surgery. On the operative day after tracheal suction she experienced bradycardia, hypotension and pulmonary hypertension followed by shock condition. In spite of vigorous medical therapy clinical aspects were not improved. But only blood transfusion directly into the left atrium and administration of tolazoline hydrochlorides through pulmonary artery were very effective to improvement of hemodynamics and reduction of pulmonary hypertension. Moreover, after this episode pulmonary artery pressure showed elevation at the tracheal suction and the weaning from the respirator. We discussed the cause and treatment of postoperative pulmonary hypertensive crisis.
Down Syndrome↗
Effects of lidocaine alone and in combination with tetraethylammonium on the maximum upstroke velocity in guinea-pig papillary muscles.
Effects of 18.5 mumol/l lidocaine on the Vmax in the absence and presence of 10 mmol/l tetraethylammonium chloride (TEA), which specifically prolongs the action potential duration with little effects on Vmax, were studied in guinea-pig papillary muscles in a 10 mmol/l K+ Tyrode solution. The frequency-dependent reduction of Vmax was significantly increased at high frequencies (3 and 4 Hz) in the presence of lidocaine plus TEA. A simulation study was performed under the assumption that lidocaine interacts with open, inactivated and resting sodium channels and that TEA specifically prolongs the inactivated state, and a reasonable fit to the experimental Vmax changes was obtained. There were no significant differences between the effects of lidocaine alone and lidocaine plus TEA on the tonic blocks, time constants and zero-time intercepts of reactivation process of Vmax. The F-test shows that these reactivation processes in all preparations examined are described sufficiently well by monoexponential functions, that is, under the assumption of the linear relationship between available sodium conductance and Vmax. The finding that a nonlinear model does not significantly improve the fit indicates the possibility that the nonlinearity may not be prominent under the present experimental conditions.
Action Potentials↗
[Aortic aneurysm associated with coarctation of the aorta].
An 8-year-old female of coarctation of the aorta associated with thoracic aortic aneurysm is reported. Under cardiopulmonary bypass, a 7 cm section of the aorta containing the aneurysm and coarctation was resected and replaced by a 16 mm woven Dacron tube. The postoperative recovery was complicated by chylothorax treated by thoracic aspiration. She is doing well 3 months after the operation. Histologic sections of the resected portions of the thoracic aorta revealed intimal hyperplasia, medial fibrosis and decrease of elastic fibers, especially in the aneurysm.
Aorta, Thoracic↗
[A case report of emergency Bentall re-operation].
A 51-year-old male of Marfan syndrome with annuloarotic ectasia underwent the Bentall operation. One and a half months later, he suddenly fell into the left ventricular failure associated with lung edema. Echocardiogram revealed total occlusion of the graft and aortic valve detachment was suspected. An emergency operation was performed. The aortic valve was completely detached due to infectious endocarditis. As anastomosed portions of the proximal coronary arteries and distal aorta were intact, these rims of the old graft were reserved. A new composite graft was anastomosed distally to the above reserved graft rims and sutured proximally to the trimmed aortic valvular ring. The patient survived the re-operation despite many post-operative complications such as mediastinitis, colon bleeding, renal failure and severe hepatic dysfunction.
Aorta↗
[Transesophageal Doppler echocardiography in the diagnosis of dissecting aortic aneurysm].
Transesophageal Doppler echocardiography (TEDE) was performed in three patients with proven or suspected DeBakey type I and type III aortic dissection. Case 1: A 66-year-old woman, with DeBakey type I aortic dissection. Clear images of a widened dissected aorta and an intimal flap were obtained in both the ascending and descending aorta, including the aortic arch. The site of an entry into the false lumen was identified by the defect of the intimal flap and the pulsatile entry flow through it. The reentry into the true lumen was also identified near the orifice of the celiac trunk. In this case, the observation was performed using this technique during the operation; i.e., replacement of the ascending aorta with an artificial graft. Case 2: A 77-year-old man, DeBakey type III aortic dissection. The study was performed after surgery which consisted of replacement of the descending aorta with an artificial graft. TEDE provided clear images of the artificial graft, the aorta, and their boundaries. The remaining intimal flap was clearly confirmed. Case 3: An 80-year-old man, DeBakey type III aortic dissection. In this case, though abdominal echography suggested aortic dissection, angiography and X-ray CT failed to facilitate the diagnosis. Only TEDE confirmed the diagnosis. The abnormal flow via the entry directing toward the false lumen was clearly demonstrated on the color Doppler images. We therefore conclude that TEDE is a useful and reliable means of diagnosing dissecting aortic aneurysm.
Aged↗
Value of rest-stress myocardial positron tomography using nitrogen-13 ammonia for the preoperative prediction of reversible asynergy.
To determine the predictive value of stress [13N]ammonia positron emission tomography (PET) for reversible ischemia, 31 patients with coronary artery disease underwent rest-stress [13N]ammonia PET before and after coronary artery bypass surgery. The circumferential profile analysis was applied to determine the presence of transient defect (TD) and persistent defect (PD) preoperatively, and the fate of perfusion abnormality and asynergy after the surgery was assessed. Preoperative PET demonstrated 100 segments with perfusion abnormalities, including 69 TD and 31 PD. Fifty-six of the 69 TD (81%) improved in regional perfusion, while only four of 31 PD (13%) improved in perfusion postoperatively (p less than 0.001). Of 75 segments showing regional asynergy on contrast or radionuclide ventriculography preoperatively, 34 of 48 segments with TD (71%) improved in asynergy, while only five of 27 segments with PD (19%) improved in asynergy postoperatively (p less than 0.001). Stress-delayed 201TI tomography was performed in 22 of them. The predictive values for improvement in perfusion (77%) and asynergy (65%) were similar as those by [13N]ammonia PET (81% and 71%, respectively). However, the predictive values for no improvement in perfusion and asynergy by 201TI tended to be low (66% and 58%, respectively), as compared to those in 13N ammonia PET (87%; p less than 0.05 and 81%; p = 0.09, respectively). We conclude that an accurate prediction of reversible ischemia and asynergy can be achieved with rest-stress [13N]ammonia PET. Particularly, it can identify irreversible areas more accurately than the commonly performed stress-delayed 201TI imaging.
Adult↗
Quantitative analysis of regional wall motion by gated myocardial positron emission tomography: validation and comparison with left ventriculography.
Electrocardiographically gated positron emission tomography (ECG-gated PET) with [13N] ammonia was used to assess regional myocardial wall motion of left ventricle (LV) based on a nongeometric method in nine healthy volunteers and 16 patients with coronary artery disease (CAD). Three transverse sections (upper, middle, and lower) with 16-mm intervals at end-diastole (ED) and end-systole (ES) were analyzed. The LV wall was divided into eight segments with every 30 degrees from septal wall to lateral wall. Based on circumferential profile analysis, the percent count increase [( ES count - ED count) divided ED count x 100) in each segment was analyzed as an index of regional wall motion. In the study of normal controls, the percent count increase was the lowest (32.9 +/- 7.2%) at septal wall of the lower slice and the highest (72.8 +/- 26.5%) at lateral wall of the upper slice (p less than 0.01). In five normal controls, the percent count increase was compared with the percent systolic wall thickening analyzed by magnetic resonance imaging, and a good correlation was observed (r = 0.84). In the study of patients with CAD, the percent count increase was compared with wall motion assessed by left ventriculography (LVG). The percent count increase significantly decreased as wall motion on LVG worsened. In addition, the value in normal controls tended to be higher than that in the segments with normal wall motion in patients with CAD. Thus, quantitative analysis of regional wall thickening was feasible by ECG-gated PET, which should be useful for combined analysis of regional function, perfusion and metabolism in patients with CAD.
Adult↗
Effect of radiation on the expression of carcinoembryonic antigen on the membranes of human gastric adenocarcinoma cells--immunological study using monoclonal antibodies.
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Adenocarcinoma↗
Immunochemical characterization of adenocarcinoma-associated antigen YH206.
The antigen recognized by MAb YH206 is mainly expressed in adenocarcinomas and is also detected in the sera of cancer patients (Hinoda et al., 1987). This antigen (antigen YH206) was chemically characterized and purified by column chromatography. SDS-PAGE analysis revealed a broad component in the high-molecular-weight range which was clearly detectable by carbohydrate (PAS) but not by protein (silver) stain. Agarose gel electrophoresis and immunoblotting of antigen YH206 indicated that it consists of a high-molecular-weight component (more than 2,000 kDa). Treatment of antigen YH206 with alkali suggested that the antigenic determinant consists of carbohydrate chains of mucin type. Density gradient ultracentrifugation revealed that the activity of antigen YH206 is localized at a density of 1.45 g/ml, suggesting that antigen YH206 is a mucin. Neuraminidase treatment of antigen YH206 indicated that the epitope is cryptic and contains an asialocarbohydrate chain. Once antigen YH206 has been purified by affinity chromatography, neither CA19-9 antigen nor DU-PAN-II antigen can be detected, although they were present at very high levels in the crude ascitic starting material; these last two are representative carbohydrate antigens which are widely used for serodiagnosis to detect adenocarcinomas.
Adenocarcinoma↗
Relation of left ventricular perfusion and wall motion with metabolic activity in persistent defects on thallium-201 tomography in healed myocardial infarction.
Myocardial viability in persistent thallium (TI)-201 defect is a controversial subject. To assess metabolic activity in segments with persistent defect, stress TI-201 tomography and positron emission tomography using nitrogen-13 ammonia and fluorine-18 2-fluoro-deoxyglucose (FDG) were performed in 28 patients with healed myocardial infarction. The segments with TI-201 perfusion defect in electrocardiogram-determined infarcted areas were selected for assessment. Stress perfusion defect was detected in 61 segments by TI-201 tomography. Twenty-two patients (36%) showed transient defects with redistribution (group 1) and 39 showed persistent defects (group 2). Increase in FDG uptake was observed in 95% in group 1. Among group 2 patients, 15 segments (38%) showed an increase in FDG uptake (group 2A) while the remaining 24 (62%) did not have an increased uptake (group 2B). The decrease in nitrogen-13 ammonia perfusion was more severe in group 2B (-23 +/- 7%) than in group 2A (-13 +/- 9%) (p less than 0.005) and group 1 (-10 +/- 4%) (p less than 0.001). In addition, wall motion scores tended to be lower in group 2B (0.21 +/- 0.71), compared with group 2A (0.67 +/- 0.70) (p = 0.05) and group 1 (0.77 +/- 0.60) (p less than 0.01). These data indicate that metabolic viability was observed in approximately 40% of the segments with persistent TI-201 defect. Preservation of regional perfusion and wall motion in these areas was similar to that in areas with transient TI-201 defect.
Aged↗
Nicorandil shortens action potential duration and antagonises the reduction of Vmax by lidocaine but not by disopyramide in guinea-pig papillary muscles.
Conventional microelectrode techniques were used to examine whether or not nicorandil, which shortens action potential duration (APD), modifies the lidocaine- or disopyramide-induced time-dependent reduction of Vmax in guinea-pig papillary muscles. First, effects of 0.1 and 1 mmol/l nicorandil were examined on the frequency dependence of Vmax and on the recovery process of Vmax. Second, the frequency-dependent reduction of Vmax by 20 mumol/l antiarrhythmic drugs was examined in the presence and absence of 1 mmol/l nicorandil at stimulation frequencies of 1/120 Hz - 5 Hz. Third, the recovery process of Vmax in the presence of 20 mumol/l antiarrhythmic drugs was examined, with and without 1 mmol/l nicorandil, by applying test stimuli at various diastolic intervals after conditioning stimuli. 1 mmol/l nicorandil greatly shortened APD90 to 30-40% of control without changing the frequency dependence of Vmax, the recovery process of Vmax, and the resting potential. The lidocaine-induced, frequency-dependent reduction of Vmax was significantly antagonised by 1 mmol/l nicorandil, but the disopyramide-induced reduction was not. The recovery process of Vmax slowed in the presence of lidocaine was antagonised by 1 mmol/l nicorandil as follows: the time to get the full recovery of Vmax was shortened by nicorandil with a significant decrease in the zero time-intercept (from 0.54 to 0.38) but with an insignificant change in the recovery time constant (from 130 ms to 121 ms). In contrast, the recovery process of Vmax slowed in the presence of disopyramide (a zero time intercept of 0.13 and a recovery time constant of 50 s) was not significantly antagonised by 1 mmol/l nicorandil. In conclusion, nicorandil having an action potential-shortening action antagonises the lidocaine-induced, time-dependent reductions of Vmax, but not the disopyramide-induced reductions. These results suggest that: (1) lidocaine and disopyramide preferentially bind to inactivated and activated sodium channels, respectively, because lidocaine's effects are dependent on and disopyramide's effects are independent of APD (during which sodium channels are in the inactivated state); and (2) nicorandil is a useful drug for estimating whether a sodium channel-blocking action of class I antiarrhythmic drugs is due to an inactivated channel block or an activated channel block. These time-dependent reductions of Vmax by both lidocaine and disopyramide were well simulated by the guarded receptor hypothesis.
Action Potentials↗
Immunohistochemical localization of atrial natriuretic polypeptide (ANP) in human atrial and ventricular myocardiocytes.
To date, there have been few immunohistochemical investigations of atrial natriuretic polypeptide (ANP) in human cardiac tissue, especially the ventricles. In this study, myocardial tissue was obtained from two sources: the bilateral atria and ventricles at autopsy; and biopsy tissues from the right auricle and left ventricle of a patient with myocardial infarction undergoing surgery. These tissues were examined by the avidin-biotin immunoperoxidase technique using three kinds of primary ANP-antibodies. ANP-immunoreactivity was observed in the perinuclear region of myocytes of all tissues examined. The intensity of the reaction was stronger in atrial tissue, weaker in ventricular tissue. In the later tissue, the positive-staining myocytes were not part of the pulse-conducting system. Although the tissues we studied were not obtained from normal hearts, our data demonstrates that ANP-reactivity can be detected in ventricular myocytes outside the pulse-conducting system.
Atrial Natriuretic Factor↗
Myocardial positron tomography with N-13 ammonia in assessment of aortocoronary bypass surgery.
A total of 20 patients were examined at rest and during stress with N-13-ammonia myocardial positron emission tomography (PET) before and after aortocoronary bypass surgery in an attempt to evaluate the effect of surgery on myocardial perfusion and to predict the graft status. The PET images were divided into anterior, septal, apical, lateral and posteroinferior segments for analysis and were evaluated as "normal" (no perfusion defects during stress and at rest), "ischemia" (stress-induced defects) and "fibrosis" (persistent defects both at rest and during stress). Approximately 90% of the segments which were ischemic before surgery became normal after surgery. Thus, ischemic changes are highly reversible, and the vessels perfusing these ischemic areas are most suitable for bypass surgery. However, most of the persistent defects failed to respond to revascularization surgery and, hence, represented irreversibly damaged myocardium. In predicting graft status, graft patency could be demonstrated by normal perfusion in postoperative images (p less than 0.01) or by improved perfusion when pre- and postoperative images were compared (p less than 0.01). However, graft occlusion could not be predicted reliably. This study demonstrated that PET with N-13 ammonia was useful in the assessment of the effects of aortocoronary bypass surgery. However, this technique was not significantly superior to thallium-201 single-photon emission computed tomography for only qualitative analysis.
Adult↗
Scanning electron microscopy of cytoplasmic filaments in rat anterior pituitary cells.
In order to demonstrate the occurrence of cytoplasmic filaments and their relationship to secretory granules, rat anterior pituitaries perfused with a detergent solution containing 0.5% Triton X-100 were observed with the scanning electron microscope. Thin section images and quick-freeze, deep-etching replica images were also studied. Scanning electron microscopy clearly demonstrated complicated networks of numerous cytoskeletal filaments in the cytoplasm of all the secretory cells of the anterior pituitary. These filaments can be classified into two groups on the basis of their diameter: thick filaments measuring 30-40 nm in diameter, and thin filaments 15-25 nm in diameter, each including the thickness of the platinum coat. The thick filaments, which run rather straight, are considered to be microtubules. The thin filaments attached to the surface of a secretory granule may connect it with an adjacent secretory granule, with cyto-organelles, with the nucleus, or with the plasma membrane. Transmission electron microscopic images of thin sections and quick-freeze, deep-etching replicas confirm the occurrence of filamentous structures associated with the limiting membrane of the secretory granule. The fine filaments associated with the limiting membrane of the secretory granule might participate in the support and transport of the granule.
Animals↗