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Biomedical subjects

Y Masuda

Publications and source records attributed to Y Masuda.

At least 865 records · Page 48Linked to original sources
PubMed1982

[Assessment of an intracardiac mural thrombus by contrast enhanced computed tomography].

The usefulness of computed tomography (CT) in the diagnosis of an intracardiac mural thrombus was examined by comparing with two-dimensional echocardiography (2-DE), left ventricular cineangiography (LVG), and operative findings. The following results were obtained: 1) Left atrial thrombi: Among 43 cases of valvular disease with mitral stenosis, left atrial thrombi were noted in 10 cases (13 regions) by CT. Out of these 13 regions, 2-DE detected six regions (Fig. 2). Among 11 patients who underwent operation, thrombi were present in four (six regions). Of these six regions, thrombus was suspected in one region and another one was undetectable, but detected in the remaining four regions by CT and was in good accord with the operative findings (Table 1). Left atrial thrombi were detected in two of 138 cases of coronary heart disease, and in one of 26 cases of cardiomyopathy by CT. 2) Left ventricular thrombi: Left ventricular thrombi were detected in 26 of 122 cases of myocardial infarction (21%) by CT, and had a particularly high incidence in the cases having a ventricular aneurysm (Fig. 4). Of 81 cases in which 2-DE was performed, left ventricular thrombi were detected in 13 cases by both CT and 2-DE, and were not detected in 59 cases by both methods. In nine cases 2-DE diagnosis was not consistent with CT (Table 2). Of 76 cases in which left ventricular cineangiography was performed, left ventricular thrombi were detected in 12 cases by both CT and LVG, and were not detected in 58 cases by both methods. There were six cases of disaccord between 2-DE and CT (Table 2). In two of five cases of congestive cardiomyopathy, left ventricular thrombi were noted by CT. CT was able to detect thrombi in the left atrial appendage, the left atrial lateral wall (Fig. 6), and the regions near the left ventricular apex, which were difficult to be investigated by 2-DE (Fig. 8). CT was, in particular, superior in depicting the size, location and property of thrombi. In addition, CT was able to depict clearly a small thrombus in the left ventricular apex to the extent of, or better than, left ventriculography. Therefore, contrast enhanced CT is a useful diagnostic method for the detection of intracardiac mural thrombi.

Cineangiography↗
PubMed1982

[Estimation of infarct size with 201Tl by multiprojection analysis].

Since mortality resulting from cardiac arrhythmia has been decreased by an introduction of CCU, power failure has become the major cause of death in patients with acute myocardial infarction. The power failure is assumed to be related to an infarct size. Therefore, noninvasive quantification of the infarct size is required for proper assessment of prognosis and treatment. Recently, a scintigraphic technique using radionuclide thallium-201 has developed, which is accumulated not in myocardial necrosis but in the intact myocardium. In this study, we tested two different parameters expressing the infarct size based on 5-projection myocardial scintigrams. One parameter is the ratio of the defect area to the total myocardium (% area), and the other is the ratio of a count decrease by the defect to total counts (% loss counts) in the planar image. Each parameter was obtained from uni- and multi-projection analysis. Six items were selected in the study including % area of 1-projection analysis, % area of 3-projection analysis, % area of 5-projection analysis, % loss counts of 1-projection analysis, % loss counts of 3-projection analysis, and % loss counts of 5-projection analysis. In 56 patients with the first attack of acute myocardial infarction, these parameters showed a clinically acceptable correlation with ejection fractions obtained by contrast ventriculography performed about 4 weeks later, with pulmonary end-diastolic pressure shortly after the onset, and with peak-CPK and sigma CPK obtained by 4 or 6 hourly measurements. Correlation coefficients between two parameters among 6 items showed no difference from each other. Scintigraphy was performed more than twice in 11 patients and the infarct size of these patients was decreased with the clinical course. Validity for estimates of the infarct size obtained with two parameters (% loss counts and % area) in different projection analysis was examined by a phantom model experiment and the clinical implications were discussed. In conclusion, an infarct size estimated by 201Tl scintigraphy provides useful informations about the size of necrosis and cardiac function in patients with acute myocardial infarction.

Adult↗
PubMed1982

[New echocardiographic criterion in the diagnosis of mitral valve prolapse].

Currently, echocardiographic diagnosis of mitral valve prolapse is made when the mitral leaflets protrude into the left atrium crossing the mitral ring. However, there remains the possibility that some mitral valve prolapse, particularly mild one, is overlooked by the currently used criterion. In the present study, new echocardiographic criterion in the diagnosis of mitral valve prolapse is proposed. The criterion includes the systolic dislocation of the mitral leaflets at its coaptation zone. The validity of the new criterion is supported by the following facts. (1) Dislocation of the mitral leaflets at the coaptation zone was never observed in healthy subjects. (2) Real-time two-dimensional echocardiograms from eight cases with a midsystolic click and a late systolic murmur, the characteristic phonocardiographic findings of mitral valve prolapse, invariably demonstrated the dislocation of either the anterior or posterior mitral leaflet at the coaptation zone leading to the diagnosis of mitral valve prolapse. Four of five cases with a midsystolic click and a holosystolic murmur were also diagnosed echocardiographically as mitral valve prolapse based on the proposed criterion. However, two of the former cases and one of the latter cases did not demonstrate the protrusion of the mitral leaflets into the left atrium crossing the mitral ring, indicating inability to diagnose mitral valve prolapse based on the commonly adopted criterion. (3) Based on the extent and degree of dislocation of the coaptation of the mitral leaflets, mitral valve prolapse could be classified into nine grades. It was found that the incidence of mitral regurgitation proved by phonocardiography or angiocardiography is higher as the grade of prolapse becomes greater.

Echocardiography↗
PubMed1982

Developmental and behavioral effects of maternal alcohol exposure in rats.

Fostered rat offspring whose mothers had been administered 7.5% alcohol solution (4.85 g/kg/day) as drinking fluid during 0-17 days of gestation were compared with equivalent groups whose dams had given ad libitum and restricted volume of tap water in the following behavioral tests: reflex test, swimming behavior test, open-field test, radial-maze learning and two-way avoidance learning. The treatment with alcohol resulted in developmental delay in ear-flaps uncurling, placing reflex, swimming behavior, walking in addition to reduction in body weight at 1 and 7 days of age. The treated group also exhibited decreased open-field activity and deficit in the avoidance learning. The results show that maternal alcohol consumption produces developmental and behavioral deficits in offspring, which are comparable to the fetal alcohol syndrome (FAS) in man.

Animals↗
PubMed1981

Analysis of pressure profile in the occluded airway obtained at the beginning of inspiration in steady state hypercapnia.

Using the steady state CO2 response test, we measured inspiratory mouth occlusion pressure and ventilatory volume in 38 normal subjects. At each degree of hypercapnia, 5 occlusion trials were performed. Occlusion pressure (Pt) and the timed differentials (dp/dtt) measured at 0.025-s intervals from the onset of inspiration until 0.2 s, dp/dt at 1 cmH2O pressure (dp/dt1 cmH2O), and peak dp/dt (dp/dtpeak) were determined. To evaluate the usefulness of these indexes, coefficients of variation and correlation coefficients with VT, normalized VE (VN), PACO, and inspiratory flow without occlusion were calculated. Coefficients of variation in Pt decreased with time from the onset of inspiration, being lowest at P.2. In contrast, those for dp/dtt were lowest at 0.075 sec, and thereafter rapidly increased. Correlation coefficients between Pt and respiratory parameters were high (0.94 to 0.98) for most times except at the very beginning of inspiration. Those between dp/dt and respiratory parameters were somewhat lower (0.91 to 0.97). Correlation of tidal volume with occlusion pressure was poor, thus the occlusion analysis was considered inappropriate to evaluate tidal volume output.

Adolescent↗
PubMed1981

Development of tolerance to the stimulatory effect of neuroleptic butyrophenones on pituitary-adrenal activity in rats.

The effects of repeated administration of haloperidol (HAL) and clofluperol (CLO) on the responsiveness of pituitary-adrenal system to these drugs were studied in rats. Chronic treatment of animals with a daily i.p. dose of 5 mumol/kg of the drugs resulted in markedly attenuated responses of plasma corticosterone (CS) to challenge of the same dose of the same drug as compared to the acute treatment which caused a large increase in the plasma CS levels. Animals receiving a chronic HAL treatment showed a complete cross-tolerance to the stimulatory effect of CLO and a nearly complete cross-tolerance to that of chlorpromazine. The adrenal cortices of animals tolerant to HAL responded normally to exogenous ACTH. This result indicates that the tolerance to the stimulatory action of the butyrophenones may occur in the hypothalamo-pituitary axis.

Animals↗
PubMed1981

Carbon tetrachloride-induced loss of microsomal glucose 6-phosphatase and cytochrome P-450 in vitro.

Rat liver microsomes were incubated in the presence of NADPH and CCl4 under various conditions, and losses of glucose 6-phosphatase (G-6-Pase) and cytochrome P-450 were examined in terms of lipid peroxidation and CCl4 metabolism. Loss of G-6-Pase activity correlated well with the enhancement of lipid peroxidation. Loss of cytochrome P-450 was also dependent on the lipid peroxidation, under aerobic conditions. However, the cytochrome was destroyed under anaerobic conditions in which lipid peroxidation and loss of G-6-Pase were greatly suppressed. This anaerobic loss of cytochrome P-450 may be linked with the metabolism of CCl4 by this hemoprotein, as evidenced by the observation that CCl4 metabolism occurred only under anaerobic conditions and was inhibited by carbon monoxide accompanied by the suppression of the loss of cytochrome P-450.

Animals↗
PubMed1981

Modeling of digestive tract lesions using silicone rubber RTV (KE-12).

In order to produce life-size models of digestive tract lesions, we applied silicone rubber RTV (KE-12) over the surface of the resected fresh, half-fixed or completely-fixed specimens to achieve their impressions. Into these impressions, super-hard plaster, acrylics and lysine base were separately poured, with the resultant casts realizing faithful replicas of the original patterns, finely reproducing their mucosal micro-structures. A photofluorogram of the silicone rubber pattern taken by using softex could reveal roentgenographic micromucosal features on a single plane. Clinically, endoscopic casting of lesions in similar procedures could produce their models, providing data available for estimation of the size and depth of an ulcer. Our method would be of help in dynamical pursuit of digestive tract lesions, as well as for comparison of the vital realities of lesions and their histopathological findings. The method may further contribute to reducing the dosage of x-ray bombardment in gastric fluoroscopy.

Animals↗