Effects of similarity on apparent motion and perceptual grouping.

Effects of similarity in colour, luminance, size, and shape on apparent motion and perceptual grouping were examined in part 1 in two parallel experiments on the same seven subjects. In both experiments, the effect of similarity was compared with that of proximity in competitive, bistable stimulus situations. A combination of a larger horizontal separation between the homogeneous stimulus elements and a smaller constant vertical separation between heterogeneous stimulus elements produced two kinds of apparent motion (or perceptual grouping) with equal probabilities. Such matched separations between homogeneous stimulus elements were obtained by the double staircase method in various stimulus conditions. In both experiments on apparent motion and perceptual grouping matched separation was found to increase as the difference between the heterogeneous stimulus elements increased. High correlations (0.71 to 0.94) of matched separations were found between apparent motion and perceptual grouping in four stimulus series: colour, luminance, size, and shape. Six of the seven subjects were also tested in part 2. Here, the effects of differences were found to work additively across different perceptual attributes in both phenomena, when multiple differences were combined in heterogeneous elements. The experimental results are discussed from the point of view that apparent motion is an example of perceptual constancy.

Ultrafast computed tomography in the diagnosis and evaluation of anomalous origin of the right coronary artery.

Anomalous origin of the right coronary artery may lead to myocardial ischemia despite the absence of atherosclerosis. We report the case of a 52-year-old man who was admitted to our hospital with exertional chest discomfort and palpitations. An anomalous origin of the right coronary artery was demonstrated by coronary angiography. There was no evidence of atherosclerosis in either the left or right coronary arteries. However, detailed information regarding the proximal portion of the anomalous artery was not acquired by coronary angiography. In this patient, ultrafast computed tomography (UFT) revealed an acute angle takeoff of the anomalous right coronary artery from the aorta. Furthermore, the proximal portion of the right coronary artery traversed the aorta and pulmonary trunk. This case illustrates that UFT is useful for detecting an anomalous origin of the coronary arteries and evaluating the mechanism of myocardial ischemia in patients with anomalous origin of the coronary arteries.

Brain SPECT with neuro-Behçet disease.

A patient with neuro-Behcet disease is described. SPECT using Tc-99m HMPAO was performed to evaluate brain perfusion. The brain SPECT revealed decreased perfusion in the right frontal, parietal, temporal, and occipital lobes. MRI showed high intensity lesions in the white matter in the right periventricular centrum semiovale and frontal region on T2 weighted images. Gray matter abnormalities were evident on brain SPECT, but not on MRI. Brain SPECT using Tc-99m HMPAO may provide useful clinical information on regional cerebral cortical abnormalities associated with neuro-Behcet disease.

[Pharmacological action of SN-408, a novel long-acting selective beta 2-adrenoceptor agonist].

The bronchodilating effect and other related pharmacological properties of SN-408 were studied in comparison with those of isoproterenol, salbutamol and procaterol. SN-408 caused concentration-dependent relaxation of isolated guinea pig trachea via the beta 2-adrenoceptor. The order of relaxation potency was: procaterol greater than SN-408 greater than or equal to isoproterenol greater than salbutamol, but the duration of the action of SN-408 was far longer than those of other beta-agonists. Positive chronotropic and inotropic actions of SN-408 in isolated guinea pig right atria and left atria were less potent than those of other beta-agonists. In isolated guinea pig lung tissues, SN-408 increased cyclic AMP contents. Also in vivo, SN-408 showed dose-dependent bronchodilating action by i.v. administration in anesthetized guinea pigs and by inhalation in conscious guinea pigs. Bronchodilating actions of SN-408 were less potent than those of procaterol and isoproterenol, but the duration of action of SN-408 was far longer than those of other beta-agonists. SN-408 showed no evidence of the development of tolerance to the bronchodilating action. SN-408 caused small tachycardia in guinea pigs by i.v. and inhalation. SN-408 given i.v. suppressed vascular permeability in mice. These results indicate that SN-408 is a long-acting and selective beta 2-stimulant bronchodilator.

[A new application of bull's-eye analysis to lung perfusion scintigraphy].

Technetium-99m macroaggregated albumin lung perfusion scintigraphy was performed and evaluated semiquantitatively by bull's-eye analysis in 24, including 7 with central pulmonary carcinoma, 3 with hypersensitivity pneumonitis (HP), 3 with diffuse panbronchiolitis (DPB) and 11 normal subjects. First, whole lung field was divided into three regions by three concentric circles. And then radial axes were projected from the center to define 36 sectors, 10 degree each. The counts of each sector was calculated and bull's-eye image and circumferential profile curve were displayed. The patient's map was compared with the lower limit of normal (mean-2 SD), and the extent score (ES) and the severity score (SS) were calculated. The ES was 0.25 +/- 0.12 in pulmonary carcinoma (n = 7), 0.08 +/- 0.07 in HP (n = 3), 0.06 +/- 0.04 in DPB (n = 3). The SS was 26.39 +/- 15.17 in pulmonary carcinoma, 4.75 +/- 5.57 in HP, 4.29 +/- 3.67 in DPB. In one case of central pulmonary carcinoma, segmental perfusion defect was evaluated semiquantitatively by bull's-eye image and circumferential profile curve. And in one case of HP, the change of regional pulmonary blood flow could be followed easily using extent and severity map. This new application of Bull's eye analysis to lung perfusion scintigraphy might be useful to evaluate regional pulmonary blood flow.

Whole-body distribution of iodine 123 metaiodobenzylguanidine in hypertrophic cardiomyopathy: significance of its washout from the heart.

Whole-body distribution of iodine 123 metaiodobenzylguanidine (123I-mIBG) was evaluated in 27 patients with hypertrophic cardiomyopathy (HCM). At 1 and 4 h after injection, anterior and posterior whole-body images were obtained with a dual-headed, camera-computer system. Patients were classified into three groups based on the septal wall thickness as determined by echocardiography: group 1 consisted of 7 patients with less than or equal to 15 mm septal thickness, group 2 included 12 patients with 16-19 mm septal thickness, and group 3 included 6 patients with greater than or equal to 20 mm septal thickness. Although the myocardial mIBG uptakes at 1 h were similar among these groups (1.84% +/- 0.19%, 1.95% +/- 0.38%, 1.98% +/- 0.57%, respectively; NS), mIBG washout from the heart in group 3 was faster than in groups 1 and 2 (31.5% +/- 13.0% vs. 15.8% +/- 11.0% (group 1, P less than 0.05), 17.6% +/- 7.3% (group 2, P less than 0.01)). There was a significant positive correlation between mIBG washout from the heart and septal thickness, with correlation coefficient r = 0.52 (P less than 0.01). The liver, lung, parotid gland, spleen and skeletal muscle showed similar mIBG uptake and washout among the three groups. We conclude from these data that mIBG washout from the heart in HCM was faster in patients with severe hypertrophy than in patients with mild to moderate hypertrophy, and hence it may be a useful parameter for evaluating the severity of altered adrenergic innervation and activities.

Two-dimensional echocardiography in acute myocardial infarction--relationship between left ventricular wall thickness and wall motion abnormalities.

An attempt was made to examine left ventricular wall thickness and wall motion using two-dimensional echocardiography from the acute phase to 1 month after onset of myocardial infarction. Motion abnormalities and thinning of the wall were observed from immediately after the onset. Few areas that were akinetic or dyskinetic and had a wall thickness of 7 mm or less during the acute phase showed improvements in wall motion 1 month later. However, some areas with a wall thickness of 8 mm or more did reveal improved wall motion even if they were akinetic or dyskinetic during the acute phase. Since the akinetic or dyskinetic areas with a wall thickness of 7 mm or less during the acute phase demonstrated a positive correlation with the peak CPK and nQ, and a negative correlation with the left ventricular ejection fraction 1 month after the onset, they were considered to be necrotic zones of myocardial infarction. The area of abnormal wall motion, on the other hand, was considered to correspond to a wider area including the ischemic as well as the necrotic zones. Evaluation of the necrotic and ischemic areas of infarction separately from the acute phase appears to be useful not only for the selection of treatment during the acute phase but also for predicting the cardiac function 1 month later and for determining the time of initiation and method of cardiac rehabilitation.

[An experimental and clinical study on the dissecting aortic aneurysm--usefulness of magnetic resonance imaging and the ultrasonic pulsed Doppler duplex system].

In the treatment of dissecting aortic aneurysm, it is important to understand the exact conditions of the disease. For this purpose Aortography (AOG) and X-ray computerized tomography (CT) have been used. Magnetic Resonance Imaging (MRI) and the ultrasonic pulsed Doppler duplex system are completely non-invasive and may be used instead of AOG and CT. Experimental aortic dissection was done surgically using modified Blanton's method in 8 mongrel dogs. MRI and the ultrasonic pulsed Doppler duplex system were used on these dogs before and after surgery which consisted of surgical closure of entry and insertion of Ivalon Sponge to false lumen. MRI patterns were classified into three: i.e., low, middle, and high intensity. The ultrasonic pulsed Doppler duplex system patterns were classified into four: i.e., normal flow, to and fro, turbulent flow and wall motion patterns respectively. These patterns of MRI and the ultrasonic pulsed Doppler duplex system were closely correlated to autopsy findings. These results indicated that MRI and the ultrasonic pulsed Doppler duplex system are useful to evaluate the changes of figures and hemodynamics of the false lumen. In the clinical study, MRI was performed on 26 patients of dissecting aortic aneurysm before and after surgery. These results were compared with those of AOG and CT. In the detection of the intimal flap, the main arterial branches, and the location of the entry and reentry, MRI was superior to CT and almost equal to AOG.