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Biomedical subjects

T Ban

Publications and source records attributed to T Ban.

At least 217 records · Page 12Linked to original sources
PubMed1985

Myocardial positron computed tomography with 13N-ammonia at rest and during exercise.

To assess the value of myocardial-perfusion positron computed tomography (PCT) for the evaluation of coronary artery disease (CAD), 13N-ammonia PCT using a whole-body multislice PCT device was performed at rest and during exercise in 6 normal subjects and 19 patients with angiographically documented CAD. The 13N-ammonia distribution in the myocardium was assessed both qualitatively and quantitatively. At rest and during exercise, the tracer distribution was homogeneous in the 6 normal cases. In the 19 patients with CAD, regional hypoperfusion was observed in 14 cases (74%) at rest and in 18 cases (95%) during exercise. Additional perfusion abnormalities were detecting during exercise in 12 cases. Segmental analysis of the myocardial perfusion identified 30 out of 34 stenosed vessels (88%) during exercise, with only one false-positive finding of diseased vessels (specificity, 98%). For the quantitative analysis of myocardial perfusion by PCT, the percentage of change in the tracer concentration in the same region between the rest and stress images was calculated. The concentration was slightly increased in normal myocardial segments (14.4% +/- 5.8%; P less than 0.001), whereas in CAD, it was significantly decreased in segments with stenosed vessels (-18.0% +/- 18.3%; P less than 0.02). We conclude that 13N-ammonia PCT at rest and during exercise provides high-quality images, and is a sensitive and effective technique for detecting CAD and identifying individual stenosed vessels. Furthermore, this technique makes possible quantitative assessment of the coronary reserve function.

Adult↗
PubMed1985

Effects of para-substituted beta-adrenoceptor blocking agents and methyl-substituted phenoxypropanolamine derivatives on maximum upstroke velocity of action potential in guinea-pig papillary muscles.

The effects of atenolol (2-5 mmol/l), sotalol (1-2 mmol/l) and pamatolol (0.1-1 mmol/l), together with N-tertiary butyl phenoxypropanolamines with o-methyl (D-2T: 50-100 mumol/l) m-methyl (D-3T: 50-100 mumol/l) and p-methyl (D-4T: 100-200 mumol/l) group as well as with o,p-methyl groups (D-24T) (50-100 mumol/l) on action potentials (APs) were investigated in isolated guinea-pig papillary muscles. All the drugs in these concentrations produced a concentration-dependent reduction of the maximum upstroke velocity (Vmax). The reduction of Vmax in premature APs induced by stimuli interpolated between the basic driving rate of 0.25, 0.1 or 0.027 Hz decayed exponentially during diastolic intervals. The time constants of these decay processes tau for atenolol, pamatolol and sotalol ranged between 260-541 ms, those for D-3T and D-4T between 655-1,166 ms, and D-2T and D-24T between 1,565-1,931 ms. A drug which provided larger tau values caused the reduction of Vmax in a wider range of the frequency.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1985

A Japanese survey on first attempts of percutaneous transluminal coronary angioplasty.

Experiences of the initial application of percutaneous transluminal coronary angioplasty (PTCA) in Japan performed during 1980-1981 at the multicenter level were analyzed. A survey in 72 cases which were collected from 12 centers showed an overall success rate of 64.7%, unimproved stenotic lesions in 8.1% and unpassable lesions in 24.3% of the cases. Complications were death of the patient in 2(2.8%), acute myocardial infarction in 6(8.3%) and dissection of the coronary artery in 3 cases (4.2%). Aortocoronary bypass graft surgery was performed in 8 cases (11.1%).

Adult↗
PubMed1985

Usefulness of intraoperative coronary angioplasty in aorto-coronary bypass surgery.

Seven patients underwent aorto-coronary bypass grafting combined with intraoperative transluminal coronary angioplasty (OTCA), because of multiple obliteration of the coronary arteries with poor distal run-off. The patients were all males with a mean age of 52.6 years. For OTCA, a SIMPSON-ROBERT vascular dilator system was used. Eight stenoses in seven patients, four in the left anterior descending artery (LAD) and three in the right coronary artery (RCA) were dilated by means of OTCA. In five patients the results were satisfactory but in two patients the procedures resulted in failure. Dilatation failed because of severe calcification of LAD in one case and, in the other, distal RCA was completely obstructed by a compressed atherosclerotic plaque at the bifurcation after the procedure. From these limited experiences we believe that OTCA might be a method of selection to treat the patients with coronary sclerosis with poor distal run-off.

Angioplasty, Balloon↗
PubMed1985

Ventricular arrhythmias late after aortic and/or mitral valve replacement.

Since it is not yet known whether ventricular arrhythmias in patients with valve replacement are associated with an increased risk of sudden death, as in patients with coronary artery disease, a total of 46 patients who were long-term survivors of aortic and/or mitral valve replacement were examined with 24-hour ambulatory electrocardiographic monitoring, and the factors influencing the occurrence of ventricular arrhythmias were analyzed. The significance of ventricular arrhythmias in the prognosis of valve replacement is discussed. The occurrence of ventricular arrhythmias was significantly higher: 1) in patients with aortic stenosis than in those with aortic regurgitation, 2) in patients with multiple valve surgery than in those with single valve replacement and 3) in patients with larger heart size. Pre- and postoperative hemodynamics, including left ventricular function, were not significantly related to the incidence of ventricular arrhythmias. A review of the patients who died suddenly, late after valve replacement suggests that frequent ventricular arrhythmias and thromboembolism are the most important factors in the late mortality of these patients. The prognostic significance of postoperative ventricular arrhythmias in patients with valve replacement requires additional study.

Adolescent↗
PubMed1985

Emergency aorto-coronary bypass surgery after percutaneous transluminal coronary recanalization--its indication and results.

Percutaneous transluminal coronary recanalization (PTCR) was carried out in 201 patients with acute myocardial infarction. Fifteen patients required emergency aorto-coronary bypass grafting (ACBG) subsequent to PTCR; in one immediately following unsuccessful thrombolysis and the remaining 14 patients within 10 days after initial successful recanalization because of reinfarction. One patient died of multiorgan failure postoperatively. Excluding one patient, all patients had left main trunk disease (LMTD) and/or 3 vessel disease (3VD), with residual stenosis at the site of recanalization of greater than 99% with filling delay. Nonsurviving without surgery and medically managed patients on whom repeated angiography was carried out also analysed, in an effort to establish angiographic indications for supplementary surgical revascularization. Patients having extensive coronary artery disease such as LMTD and/or 3VD, emergency ACBG should be performed immediately following PTCR, if the remaining causative stenosis is greater than 99% with filing delay.

Aged↗
PubMed1985

Electron-microscopic studies on morphological changes in the surface mucous cell during migration in the stomach of the golden hamster.

Morphological changes in the surface mucous cells in the gastric body of the golden hamster occurring during their movement from the lower to the upper portion of the gastric pit have been observed by using scanning as well as transmission electron microscopes. The cells have a wide base and a narrow apex in the lower and middle portions of the pit, while at the opening of the pit to the gastric lumen, they become taller and funnel-like in shape, and are characterized by well developed interdigitations and intermediate filaments sometimes associated with desmosomes. During this transformation of the cell contour, the nucleus moves towards the upper region of the cytoplasm, whereas the Golgi apparatus moves downwards to the infranuclear region. Then, there appear secondary lysosomes showing crinophagy and lipid droplets around or near the Golgi apparatus. Though the basal part of the cells is very small, no images of the detachment of the basal plasma membrane from the basal lamina could be seen even at the site of severe cell degeneration. The tall funnel-shaped cells showing these characteristics are located on the interfoveolar ridges of the underlying fibrous layer and line the free surface of the stomach. Therefore, the interfoveolar cells which have lost the activity of secretory granule production and are going to undergo physiological degeneration are thought to be highly differentiated elements as a covering epithelium to protect the underlying tissue, resembling in this respect the keratinocyte of the epidermis.

Animals↗
PubMed1985

Dynamic positron computed tomography of the heart with a high sensitivity positron camera and nitrogen-13 ammonia.

Dynamic positron computed tomography (PCT) of the heart was performed with a high-sensitivity, whole-body multislice PCT device and [13N]ammonia. Serial 15-sec dynamic study immediately after i.v. [13N]ammonia injection showed blood pool of the ventricular cavities in the first scan and myocardial images from the third scan in normal cases (n = 4). In patients with myocardial infarction (n = 8) and mitral valve disease (n = 2), tracer washout from the lung and myocardial peak time tended to be longer, suggesting presence of pulmonary congestion. PCT delineated tracer retention in the dorsal part of the lung. Serial 5-min late dynamic study in nine cases showed gradual increase in myocardial activity for 30 min in all normal segments and 42% of infarct segments, while less than 13% activity increase was observed in 50% of infarct segments. Thus, serial dynamic PCT with [13N]ammonia assessing tracer kinetics in the heart and lung is a valuable adjunct to the static myocardial perfusion imaging for evaluation of various cardiac disorders.

Ammonia↗
PubMed1985

[Myocardial positron computed tomography using N-13 ammonia for evaluating coronary artery disease: comparison with thallium-201 emission computed tomography].

To assess myocardial perfusion in patients with coronary artery disease (CAD), N-13 ammonia positron computed tomography (PCT) was performed for 32 cases, and the PCT images were compared with those of single-photon emission computed tomography (SPECT) using thallium-201. Myocardial perfusion images were obtained with a whole-body multislice PCT device following the intravenous injection of 10 to 20 mCi N-13 ammonia at rest (32 cases) and during exercise (23 cases). Eleven cases underwent serial 15-20 second dynamic studies immediately following the N-13 ammonia injection. Serial dynamic study showed the blood-pool images in the first scan, and enabled assessment of tracer washout from the blood-pool, and the lung as well as washin into the myocardium. PCT provided clear resting myocardial perfusion images in all cases. PCT images were of higher quality than those of SPECT due to higher spatial resolution with less statistical noise, allowing delineation of the right ventricular myocardium and papillary muscles in many cases. Both PCT and SPECT detected perfusion abnormalities in 18 of the 19 cases with myocardial infarction, without false positive findings. PCT yielded stress myocardial images and permitted comparative evaluations of myocardial perfusions at rest and during exercise in all 23 cases. Perfusion abnormalities were detected in 14 cases (74%) at rest and in 18 cases (95%) during exercise among 19 patients with CAD. No false positives were observed, either by resting or stress PCT imaging. Stress myocardial PCT identified regional perfusion abnormalities in 30 of the 34 regions supplied by stenosed vessels (88%). High resolution PCT images enabled precise evaluation of myocardial perfusions which proved valuable for assessing myocardial perfusions before and after aorto-coronary bypass surgery. The present study proved advantages of N-13 ammonia PCT in creating three-dimensional high resolution images of the myocardium, which facilitates precise evaluation of myocardial perfusions. Furthermore, its potential capabilities in quantifying coronary reserve function will be very useful. This method should provide valuable pathophysiological information for CAD, as well as for metabolic PCT imaging.

Ammonia↗
PubMed1984

Radioimmunoassay for alpha-human and rat atrial natriuretic polypeptide.

Using a synthetic common carboxy-terminal fragment of alpha-human atrial natriuretic polypeptide (alpha-hANP) and alpha-rat atrial natriuretic polypeptide (alpha-rANP), we have produced an antiserum for alpha-ANP(17-28) and established a radioimmunoassay (RIA) for alpha-ANP that recognizes alpha-hANP and alpha-rANP equally. High performance gel permeation chromatography coupled with the RIA revealed that alpha-hANP-like immunoreactivity (alpha-hANP-LI) in the human atrium consists of three major components, gamma-hANP, alpha-hANP and another. On the other hand, alpha-rANP-LI in the rat atrium comprised at least two components, 13K alpha-rANP-LI and 3K-5K alpha-rANP-LI, which were presumably gamma-rANP and beta-rANP, respectively. Thus, considerable amounts of gamma-hANP and gamma-rANP are present in human right auricles and rat atria, respectively. The RIA established in this study provides a useful tool to investigate the pathophysiological significance of alpha-ANP and related peptides in cardiovascular disorders and shows that gamma-ANP is not only a precursor of alpha-ANP but acts as an important hormone.

Amino Acid Sequence↗
PubMed1984

Commissural afferents to the cortex surrounding the posterior part of the superior temporal sulcus in the monkey.

Commissural afferents to the cortex surrounding the posterior part of the superior temporal sulcus were studied in Japanese monkeys by the horseradish peroxidase method. After injection of the enzyme, many callosal neurons were labeled contralaterally in the cortical area corresponding to the injection site (homotopical area) and in other regions (heterotopical area). Most of the callosal neurons were triangular in shape, occurring for the most part in layer III of both homotopical and heterotopical areas (about 75-90% of the total number of labeled cells). Mean diameters of the cell bodies were about 11-13 micron.

Animals↗
PubMed1984

Immunocytochemical demonstration of caldesmon (a calmodulin-binding, F-actin-interacting protein) in smooth muscle fibers and absorptive epithelial cells in the small intestine of the rat.

The distribution of caldesmon (a calmodulin-binding, F-actin-interacting protein) (Sobue et al. 1982) and of actin was studied in the rat's small intestine by means of light-microscopic immunocytochemistry. Positive immunostaining for caldesmon was seen in smooth muscle cells of the intestinal wall, and of blood vessels, and in the apical portion of the absorptive epithelial cells. The immunoreactivity in goblet cells was difficult to recognize. The positive reaction to immunostaining for actin showed almost the same pattern as that for caldesmon. These results suggest that this calmodulin-binding protein may play an important role in the control of actin-myosin interaction in smooth muscle cells and in non-muscle cells.

Actins↗