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Biomedical subjects

T Ban

Publications and source records attributed to T Ban.

At least 127 records · Page 7Linked to original sources
PubMed1991

Reperfusion injury in dog hearts with permanent occlusion of a coronary artery, probably due to reperfusion via collateral vessels.

To clarify whether or not reperfusion injury occurs in the permanent occlusion of a coronary artery, we analyzed quantitatively contraction band necrosis as an indicator of early recanalization, coagulation necrosis, infarct size and measured regional blood flow in dog hearts with collateral circulation. Fifty mongrel dogs were divided into four groups: 15 dogs with a 24-hour occlusion of the left anterior descending coronary artery just distal to the first diagonal branch (permanent occlusion group): 15 dogs a with 3-hour occlusion followed by 24-hour recanalization (recanalization group); 10 dogs with a 2-hour occlusion without recanalization (transient occlusion group); 10 dogs with a 4-hour occlusion without recanalization (transient occlusion group). The regional blood flow in the subepicardium and subendocardium determined by the generated hydrogen gas clearance method was greatly decreased 30 minutes after occlusion (14 + 8%/12 +/- 9%) and was relatively restored from 180 minutes (31 +/- 21%/21 +/- 14%) to 24 hours later (41 + 19%/26 + 16%) in spite of complete occlusion of the coronary artery. The percentage infarct area in the risk area was significantly greater in the permanent occlusion group (60 +/- 26%) than in the recanalization group (35 +/- 31%). Although most of the infarct was occupied by contraction band necrosis in the recanalization group (86 +/- 12%), contraction band necrosis was diffusely seen even in the permanent occlusion group (54 +/- 27%). In both the permanent and recanalization groups, contraction band necrosis was the main histological feature of small infarcts occupying less than 30% of the risk area, while coagulation necrosis was the main feature in very large infarcts occupying more than 80% of the risk area. In the occlusion groups without recanalization, the percentage area of contraction band necrosis in the risk area was 6 +/- 8% after the 2-hour occlusion, 23 +/- 17% after the 4-hour occlusion and 31 +/- 21% after permanent occlusion; the difference between the 4-hour and permanent occlusion groups was not significant. In the permanent occlusion group, the percentage infarct area in the risk area was inversely correlated with regional blood flow during occlusion, an indicator of collateral flow. It was concluded that reperfusion injury occurs even in hearts without recanalization. The pathogenesis may involve reperfusion in the risk area via collateral circulation. Protection against reperfusion injury is important to minimize the infarct size even in hearts with permanent occlusion, although the presence of collateral flow is an important factor in limiting infarct size.

Animals↗
PubMed1991

Skeletal muscle powered ventricle: comparison of double-layered small ventricle and single-layered large ventricle.

Canine left latissimus dorsi (LD) muscles were used to construct two kinds of skeletal muscle powered ventricles (SMPV): a double layered small size (10-17 mL) SMPV (A), and a single-layered large size (40-70 mL) SMPV (B). The same muscle was used sequentially for the construction of both SMPV. A mock circulation system was used for testing. This allowed for change of the preload (10-60 mmHg) and afterload (40-160 mmHg) independently. The peak developed pressure (PDP) and stroke volume (SV) were measured, and the stroke work (SW) was analyzed on line by a computer. The isovolumic PDP was 93.3 +/- 11.8 mmHg at 10 mmHg preload, and 157.7 +/- 20.2 mmHg at 60 mmHg for A, and 37.8 +/- 5.5 mHg and 107.8 +/- 8.5 mmHg for B. The SV and SW at 50 mmHg preload and 80 mmHg afterload were 18.30 +/- 1.25 mL and 1.06 +/- 0.10 x 10(6) erg for A, and 34.18 +/- 2.36 mL and 2.51 +/- 0.28 x 10(6) erg for B. The SV and SW at 20 mmHg preload and 160 mmHg afterload were 2.65 +/- 0.31 mL and 0.27 +/- 0.05 x 10(6) erg for A, and 1.03 +/- 0.23 mL and 0.04 +/- 0.01 x 10(6) erg for (B). The SW generated by the large single-layered SMPV is similar to that reported for the canine left ventricle but requires a high preload. The large single-layered SMPV showed a higher dependence on pre- and afterload changes than the double layered small SMPV, which generates a higher pressure even at low preloads.

Animals↗
PubMed1991

Relation of change in wall motion and glucose metabolism after coronary artery bypass grafting--assessment with positron emission tomography.

Regional myocardial glucose metabolism was assessed by positron emission tomography (PET) in stunned myocardium. PET perfusion and metabolic imaging using N-13 ammonia and F-18 deoxyglucose (FDG) was performed before and 5-7 weeks after coronary artery bypass grafting (CABG) in 23 patients with coronary artery disease. Of 22 asynergy segments showing increased FDG uptake preoperatively, the postoperative PET showed a decrease in FDG uptake in 16 segments (73%) and persistent uptake in 6 segments (27%). The improvement in asynergy was observed in all of the segments showing postoperative decrease in FDG uptake, while it was observed in only 50% of those with persistent FDG uptake (p less than 0.01). On the other hand, 4 of 5 segments showing a new FDG uptake postoperatively revealed deterioration of wall motion abnormality. These data suggest that an increase in exogenous glucose utilization may often persist in postischemic myocardium. Improvement in regional function seems to be associated with the improvement in metabolic abnormality after CABG.

Adult↗
PubMed1991

[Detection of the new tumor marker MUSE 11 antigen in sera of pancreatic cancer patients: a comparison with sialyl SSEA-I antigen].

Using sera from patients with pancreatic cancer and chronic pancreatitis, we measured the level of the adenocarcinoma-associated antigen MUSE 11. A comparative study between levels of MUSE 11 and levels of sialyl SSEA-1 antigen (SLX) was also carried out. With respect to the MUSE 11 antigen, positive incidence was found in 17 out of 26 pancreatic cancer patients (65%), and in 1 out of 13 chronic pancreatitis patients (8%). Similar results were obtained from the assay of SLX levels. However, no correlation was found between the two markers. Out of 9 samples which showed MUSE 11 negative, three were positive for SLX. Out of 13 samples showing SLX negative, seven were positive for MUSE 11. Twenty out of 26 (77%) cases showed positive results for either antigen. These data suggest that the MUSE 11 antigen may be useful for the diagnosis of pancreatic cancers.

Adult↗
PubMed1991

Effects of ulinastatin in experimental acute arterial occlusion in rats.

The effects of ulinastatin (human urinary trypsin inhibitor, UTI) were studied in experimental acute arterial occlusion in rats. The experimental model comprised concurrent cross-clamping of the abdominal aorta and bilateral femoral arteries for 4 hours. Blood was sampled for measurement of the enzymes 2 hours after release of the clamps. The rats were grouped according to method of infusing UTI and/or physiologic saline solution. When UTI was infused continuously from the start of clamping, the plasma creatine phosphokinase and plasma beta-glucuronidase levels were significantly lower than in the control rats (p less than 0.05). The results suggest that UTI prevents the destruction of the lysosomal membrane in acute arterial occlusion.

Acute Disease↗
PubMed1991

Cortico-cortical projections from the prefrontal cortex to the superior temporal sulcal area (STs) in the monkey studied by means of HRP method.

Cortico-cortical connections from the prefrontal cortex to the superior temporal sulcal cortex (STs area) were studied in the monkey by means of retrograde axonal transport of horseradish peroxidase (HRP). After injections of 0.15-0.6 microliter of 50% HRP into the STs area, labeled cells were found in various cortical regions. In the prefrontal-STs projections, main features of topographic correlation were revealed; the posterior part of the STs area receives fibers from the superior frontal convexity (areas dorsal to the principal sulcus) and areas 8 and 6, whereas the anterior part of the STs area receives fibers from the inferior frontal convexity (areas ventral to the principal sulcus) and the frontal pole (area FD). The principal sulcus sends fibers to the entire STs area except for its ventral wall of the posterior part. A small cortical area adjacent to the inferior ramus of the arcuate sulcus (area 45 of ref. 41) sends fibers to the entire STs area. In addition, the orbitofrontal cortex projects mainly to the rostral part of the STs area, and the parahippocampal gyrus (areas TF and TH) projects to the deeper part of the entire STs area.

Afferent Pathways↗
PubMed1991

[Doppler echographic evaluation of pressure gradients of Björk-Shiley valve in the aortic position at rest and with exercise].

Pressure gradient across the Björk-Shiley (B-S) valve in the aortic position was assessed by Doppler echocardiography at rest and with exercise. There was close correlation between peak pressure gradient and area index which is a ratio of geometric orifice area (cm2) to body surface area (BSA) (m2). The correlation coefficient was -0.70 at rest and -0.86 with exercise. High peak pressure gradients with exercise were observed in the patients with 19 mm size (71 mmHg) and 21 mm size (107 mmHg). To avoid residual left ventricular outflow obstruction with exercise, it is considered advisable to use a #19 B-S valve in patients with BSA smaller than 1.1 m2, a #21 B-S valve in patients with BSA smaller than 1.4 m2, a #23 B-S valve in patients with BSA smaller than 1.8 m2, and a #25 B-S valve in patients with BSA smaller than 2.3 m2. If proper size of B-S valve cannot be inserted, aortic or aortic-mitral patch annuloplasty or the use of bileaflet valve are recommended as procedures of choice for small aortic annulus.

Aortic Valve↗
PubMed1991

Does atrial appendectomy aggravate secretory function of atrial natriuretic polypeptide?

The present study was designed to clarify how atrial appendectomy affects hemodynamics and secretory function of atrial natriuretic polypeptide in the failing heart. Eleven mongrel dogs were prepared for the experimental model of high-output heart failure by creation of arteriovenous fistulas between femoral arteries and veins. Two months after the first operation, effects of bilateral atrial appendectomies on basal and pacing-induced secretions of atrial natriuretic polypeptide were investigated in five dogs with simultaneous measurement of various hemodynamic indices. In the remaining six dogs, used as a control group, pacing-induced secretion of atrial natriuretic polypeptide was examined in the same way as in the appendectomy group. After excision of the atrial appendages, neither systolic blood pressure nor either atrial pressure changed, but plasma atrial natriuretic polypeptide level was decreased (292 +/- 54 to 188 +/- 47 pg/ml, p less than 0.01) and cardiac output fell (3.7 +/- 0.9 to 3.0 +/- 0.8 L/min, p less than 0.01). During pacing-induced tachycardia, the peak level of plasma atrial natriuretic polypeptide was lower in the appendectomy group than in the control groups (593 +/- 213 versus 1170 +/- 324 pg/ml, p less than 0.05), despite similar left atrial pressures in the two groups. The excised appendages contained approximately 30% of the total amount of atrial natriuretic polypeptide. These results demonstrate that atrial appendectomy decreases secretory function of atrial natriuretic polypeptide and reduces cardiac output in dogs with experimental high-output heart failure.

Animals↗
PubMed1991

Prediction of reversible ischemia after coronary artery bypass grafting by positron emission tomography.

Metabolic imaging using positron emission tomography (PET) facilitates the identification of ischemic but viable myocardium. In this study, the predictive value of PET for identifying improvement in regional function after coronary artery bypass grafting (CABG) was assessed. PET perfusion and metabolic imagings using N-13 ammonia and F-18 deoxyglucose (FDG) were performed before and 5-7 weeks after CABG in 25 patients with coronary artery disease. Each of the 5 myocardial segments of the left ventricle was categorized as normal, ischemic and infarcted based on the findings of perfusion and PET metabolic images. Among 58 hypoperfused segments, abnormal perfusion in 17 of 25 ischemic segments was correctly predicted to be reversible (68% prediction accuracy), and that in 25 of 33 infarcted segments were correctly predicted to be irreversible (76% prediction accuracy) (p < 0.001). Similarly, among 53 asynergy segments assessed by radionuclide ventriculography, abnormal wall motion in 21 of 27 asynergy segments was correctly predicted to be reversible (78% prediction accuracy), and that in 21 of 26 PET viable segments was correctly predicted to be irreversible (81% prediction accuracy) (p < 0.001). Thus, preoperative metabolic imaging using PET appears to be useful for predicting responses to CABG.

Adult↗
PubMed1991

[Minimal redistribution of thallium-201 representing reversible ischemia after coronary bypass surgery: value of quantitative analysis of exercise thallium-201 SPECT].

We previously reported the value of minimal redistribution (MR) of thallium-201 in analyzing quantitative polar map analysis (QNT) which correlated well with metabolic activity on FDG-PET. To determine whether ischemic areas that have redistribution are truly reversible, we performed stress and 3-hr delayed thallium-201 SPECT imaging and radionuclide ventriculography (RNV) in 41 patients with coronary artery disease before and after coronary bypass surgery (CABG). Redistribution (RD) was categorized into 4 grades: complete RD (CR), incomplete RD (IR), MR and persistent defect (PD). MR was defined as the segment that showed > or = 2SD improvement in more than 1/3 of the area on QNT, but RD was not evident by visual analysis. 1. QNT identified MR in 30 of 56 segments (54%) where PD is noted by visual inspection. 2. The MR segments showed severer wall motion abnormality (wall motion score: 1.83 +/- 1.12) than did the IR or CR segments (0.99 +/- 1.04) (p < 0.01), but the wall motion was well preserved, compared to the PD segments (2.54 +/- 0.90) (p < 0.01). 3. The grade of RD was compared with improvement in regional perfusion and wall motion on RNV after CABG. Improvement in perfusion was observed in 62 of 77 IR or CR segments (81%) and in 17 of 30 MR segments (57%), but in only 3 of 26 PD segments (12%) (p < 0.01). 4. Similarly, improvement in wall motion was observed in 45 of 57 IR or CR segments (79%) and in 22 of 27 MR segments (81%), but in only 5 of 25 PD segments (20%) (p < 0.01). Thus, the MR segments should be considered reversible after CABG. We conclude that QNT of RD should be performed to detect RD which is slight, yet suggestive of viability.

Aged↗
PubMed1991

[Voltage-dependent effects of lidocaine and its metabolite, monoethylglycine xylidide (MEGX), on maximum rate of rise (Vmax) of action potential upstroke in guinea-pig papillary muscles].

We studied the effects of lidocaine and MEGX on the sodium current, using Vmax as an indicator, at an extracellular potassium concentration ([K]o) of 10 mmol.l-1, and compared the present results with those obtained at 5.4 mmol.l-1 [K]o in our previous study. At 10 mmol.l-1 [K]o, both lidocaine (10 micrograms.ml-1) and MEGX (10 micrograms.ml-1) significantly decreased the Vmax at the steady-state of 1 Hz, caused a significant rate-dependent decrease in Vmax, and slowed the recovery kinetics of Vmax. These effects of both agents were more prominent than those obtained at 5.4 mmol.l-1 [K]o, suggesting that MEGX as well as lidocaine produce voltage-or [K]o-dependent blocking effects on Vmax.

Action Potentials↗
PubMed1991

Metabolic activity in the areas of new fill-in after thallium-201 reinjection: comparison with positron emission tomography using fluorine-18-deoxyglucose.

Reinjection of thallium-201 after recording the 3-hr delayed scan often demonstrates improvement in areas of persistent abnormalities. To determine the metabolic activity of these areas, the changes seen on stress/redistribution/reinjection thallium SPECT were compared with PET using fluorine-18-fluorodeoxyglucose (FDG) in 18 patients with coronary artery disease. Of 48 segments showing no redistribution on the delayed scan, the reinjection scan identified new fill-in in 20 segments (42%), all of which demonstrated FDG uptake. In contrast, only 7 of the 28 segments (25%) showing no fill-in after reinjection were PET viable (p less than 0.01). Eleven patients had coronary bypass graft surgery after the radionuclide study. The majority of the segments showing redistribution (87%) and new fill-in after reinjection (65%) improved in wall motion, whereas only eight segments (25%) without new fill-in improved after surgery. Of those without new fill-in, two segments showing PET ischemia improved in wall motion, whereas the remaining six segments showing PET scar did not improve after surgery. Thus, the segments showing new fill-in after reinjection are PET viable myocardium. However, reinjection thallium imaging still underestimates the extent of tissue viability compared to PET imaging.

Coronary Circulation↗
PubMed1991

Regional wall thickening of left ventricle evaluated by gated positron emission tomography in relation to myocardial perfusion and glucose metabolism.

Regional wall thickening was assessed by electrocardiographically gated positron emission tomography (ECG-gated PET) in 26 patients with coronary artery disease. The standardized percent count increase from end-diastole to end-systole (S-percent Cl) was calculated as an index of wall thickening. The S-percent Cl was 77.8% +/- 28.9% in the segments with normal perfusion at rest, 51.9% +/- 29.5% in those with mild hypoperfusion, and 32.8% +/- 30.9% in those with severe hypoperfusion (p less than 0.001, each). Among the segments with resting hypoperfusion, the S-percent Cl was 38.9% +/- 31.5% in those without stress-induced ischemia and 48.7% +/- 30.9% in those with ischemia (p less than 0.05). Furthermore, among resting severe hypoperfusion, the S-percent Cl was 23.0% +/- 23.9% in the segments without fluorine-18-fluorodeoxyglucose (FDG) uptake and 37.8 +/- 32.9% in those with FDG uptake (p less than 0.05). These results suggest that stress-induced ischemia and FDG accumulation correlated with wall thickening. Thus, quantitative analysis of regional wall thickening seems to be useful for combined analysis of regional function, perfusion and metabolism in coronary patients.

Adult↗
PubMed1991

Sterol carrier protein2 (SCP2)-like protein in rat aorta.

Immunoblot analysis using affinity-purified antibody against sterol carrier protein2 (SCP2) showed that SCP2-like protein exists in 105,000 x g supernatant of rat aorta. Analysis of subcellular distribution of SCP2-like protein in rat aorta was determined with enzyme immunoassay (EIA). The highest level of SCP2-like protein was observed in cytosolic fraction, while the lowest level was in nuclear fraction. Analysis of marker enzymes in subcellular fractions showed that catalase, a marker enzyme of peroxisomes, leaked to cytosolic fraction to a significant extent during subcellular preparation, suggesting that SCP2-like protein in cytosolic fraction of rat aorta might be partially originated from peroxisomes. In vitro addition of homogenous SCP2 purified from rat liver dose-dependently stimulated the formation of [14C]cholesteryl esters from exogenously added [14C]cholesterol by acyl-CoA:cholesterol acyltransferase (ACAT) in microsomal preparation of rat aorta. However the addition of cytosolic fraction did not enhance cholesterol esterification by ACAT, most likely due to a markedly low level of SCP2-like protein in this fraction. The role of SCP2 in the formation of cholesteryl esters by ACAT in rat aorta was discussed.

Animals↗
PubMed1990

Value of thallium-201 reinjection after delayed SPECT imaging for predicting reversible ischemia after coronary artery bypass grafting.

The reinjection of a small dose (40 MBq) of thallium-201 after stress and delayed imaging often shows new redistribution in the regions with persistent defect. To assess whether these segments may represent reversible ischemia, reinjection thallium-201 single-photon emission computed tomography (SPECT) was performed after stress and 3-hour delayed imaging in 24 patients before coronary artery bypass grafting (CABG). The left ventricular myocardium was divided into 5 myocardial segments and regional wall motion was scored on a scale from 0 (normal) to 4 (dyskinesia). Thallium-201 findings were compared with improvement in regional perfusion and wall motion 1 to 2 months after CABG. The reinjection imaging identified new redistribution in 15 of 32 persistent defects (47%) on the 3-hour delayed images. In the study of stress and delayed SPECT imaging, the improvement in perfusion was observed in 34 of 43 segments (79%) exhibiting redistribution and 15 of 32 (47%) segments without redistribution (p less than 0.01). The reinjection SPECT identified new redistribution in 12 of the 15 improved segments that were not detected on the delayed images. Similarly, the improvement in wall motion was observed in 23 of 31 segments (74%) exhibiting redistribution and 14 of 30 segments (47%) without redistribution on the delayed images (p less than 0.05). The reinjection identified new redistribution in 10 of the 14 improved segments that were undetected on the delayed images. The predictive values for improvement in perfusion and wall motion by the reinjection imaging were significantly higher (92 and 89%) than those by the delayed imaging (69 and 62%, respectively, p less than 0.05 each).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Significance of adenocarcinoma-associated antigen YH206 levels in the pancreatic juice.

We measured the pancreatic juice levels of antigen YH206, which is a new tumor marker of adenocarcinomas detected by monoclonal antibody YH206 (Hinoda et al., Int. J Cancer 24(5):653-658, 1988). Sandwich enzyme immunoassay revealed that samples from patients with pancreas cancer (n = 21) showed significantly higher values (P less than 0.01) than those of healthy controls (n = 15). Eight out of 21 (38.1%) samples from patients with pancreas cancer showed more than 100 U/ml, whereas only one out of 20 (5.0%) from patients with chronic pancreatitis exhibited more than 100 U/ml of antigen YH206. Simultaneous measurement of antigen YH206 and CA19-9 demonstrated that although a higher incidence of positivity in the case of pancreas cancer was obtained for both antigens, antigen YH206 showed much lower incidence of positivity (14%) than CA19-9 (57%) in patients with chronic pancreatitis. Therefore, the measurement of antigen YH206 in the pancreatic juice could be of use for the diagnosis of pancreas cancer.

Adenocarcinoma↗