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Biomedical subjects

J Yamazaki

Publications and source records attributed to J Yamazaki.

At least 145 records · Page 8Linked to original sources
PubMed1987

[The evaluation of cardiac function and the effect of therapy in acute myocardial infarction--comparison by radio nuclide method in acute and chronic phase].

The cardiac function and the effect of therapy in patients with acute myocardial infarction (AMI) were assessed in over 100 patients by analysis of 201Tl-scintigraphy and 99mTc-gated pool study in our ICU. The cardiac function and 201Tl-defect ratio were compared with the results obtained in chronic phase. Sixteen of them were treated with intravenous urokinase (UK) within 6 hours from onset. The other 18 patients without UK treatment served as a control group. Significant correlation was recognized between 201Tl-defect ratio and peak-CPK levels, peak-GOT levels, peak-LDH levels. Significant correlation (r = -0.655, r = -0.713) were found between 201Tl-defect ratio and LVEF in acute and chronic phase. The UK group showed a significant increase of LVEF as compared with the control group in patients with antero-septal (A/S) AMI. In inferior (INF) AMI, no significant differences were observed UK and control group in LVEF, RVEF and 201Tl-defect ratio. In chronic phase, improvements of LVEF and 201Tl-defect ratio were observed in patients with A/S AMI. But no significant differences of LVEF, RVEF and 201Tl-defect ratio were observed in A/S AMI in acute and chronic phase. The UK group showed a significant increase of LVEF (50.1%) as compared with the control group of A/S AMI in chronic phase. We have demonstrated that a combination of 201Tl-scintigraphy and 99mTc-gated pool study are useful techniques in ICU, to evaluate the cardiac function and the effect of thrombolysis therapy and thus greatly contribute to the primary care of AMI cases.

Female↗
PubMed1986

The actions of ivermectin on cultured chick spinal cord neurons.

The effects of ivermectin (IVM) on cultured chick spinal neurons sensitive to GABA agonists were investigated. IVM caused a change of membrane potential which was associated with an increase in membrane conductance, apparently reversed at about -40 mV and weakened by repetitive application. Furthermore, this agent did not have any effects on either the actions of GABA agonists on neurons or [3H]GABA efflux from those cells. These results suggest that IVM increases membrane conductance through sites which are different from GABA recognition sites.

Animals↗
PubMed1986

Effects of carbamazepine and valproic acid on brain immunoreactive somatostatin and gamma-aminobutyric acid in amygdaloid-kindled rats.

Somatostatin and gamma-aminobutyric acid (GABA) concentrations were evaluated in the brain of kindled rats treated chronically with carbamazepine and valproic acid. Kindled seizures were almost completely blocked by treatment with carbamazepine, whereas the effect of valproic acid was partial, suppressing only generalized seizures. The duration of after-discharge in amygdala was suppressed by carbamazepine not by valproic acid. Carbamazepine induced a decrease in immunoreactive somatostatin concentration and an increase in GABA concentration in the temporal cortex of kindled rats. Valproic acid induced only an increase in GABA concentration. The results suggest that somatostatin may be associated with the suppression of focal seizure in amygdala and GABA may have a role in the suppression of generalized seizures.

Amygdala↗
PubMed1986

[Effect of hemodialysis on left and right ventricular function--evaluation using electrocardiogram gated radionuclide ventriculography].

Eighteen outpatients with chronic renal failure undergoing hemodialysis (HD) were studied. Immediately before and after HD, the left and right ventricular function measured by electrocardiogram gated radionuclide ventriculography (RNV). By HD, body weight changed 58.6 +/- 7.50 kg to 57.2 +/- 6.80 kg and BUN level changed 67.9 +/- 29.00 mg/dl to 37.1 +/- 18.96 mg/dl and creatinine level changed 11.3 +/- 3.90 mg/dl to 6.8 +/- 2.48 mg/dl. Before HD, cardiac output was 8.08 +/- 1.50 l/min and cardiac index was 5.00 +/- 0.87 l/(min m2). Left ventricular function improved (LVEF changed 60.4 +/- 6.85% to 64.2 +/- 8.7%, LVEF/LVET changed 0.237 +/- 0.048%/ms to 0.254 +/- 0.021%/ms) between before and after HD, but there was not significant difference. Right ventricular function improved (RVEF changed 41.2 +/- 8.00% to 50.0 +/- 11.96, RVEF/RVET changed 0.167 +/- 0.028%/ms to 0.209 +/- 0.059%/ms) between before and after HD, and there was significant difference (p less than 0.05).

Adult↗
PubMed1986

[Evaluation of the visualized left atrium by 201Tl myocardial scintigraphy].

201Tl myocardial scintigraphy was evaluated in patients with 18 mitral stenosis cases. Left atrium was to be seen in ANT (16.7%), LAO (16.7%), MLAO (16.7%) and L-LAT (11.1%), respectively. Furthermore, 201Tl uptake ratio of left atrium, right ventricle, pulmonary area tended significantly to increase in visible group compared with invisible group. PCW pressure was correlated with left atrial Tl uptake (r = 0.51, p less than 0.005), and it indicated some correlation between left atrial pressure and 201Tl uptake.

Adult↗
PubMed1986

Exercise-induced renal dysfunction studied by 99mTc-DTPA in hypertensives and normotensive controls.

With the purpose of studying the effect of exercise on renal function in hypertensive patients, renal dynamic studies were performed with the aid of 99mTc-diethylenetriamine pentaacetate (DTPA). Serial renal images were taken at rest and during bicycle ergometric stress in 14 hypertensive patients (H) and 14 normotensive controls (N). Renograms were constructed, and glomerular filtration rate was determined by the method of Gates [2]. Exercise resulted in a prolongation of peak time, an increase in radioisotope retention rate at 10 minutes (10-min counts/peak counts) on renograms, and a decrease of GFR in both H and N. Plasma renin activity, aldosterone, and catecholamines were all elevated during exercise in both H and N. Our data indicate that the exercise-induced renal dysfunction demonstrated by 99mTc-DTPA renograms is not specific to H but can also be observed in N, which may have resulted from changes common to H and N, as indicated by the change of GFR and humoral factors. These findings suggest that the renal response to exercise may be a more complex pathophysiologic process than that measured by the DTPA renogram, at least in its simplified form, and should encourage further work in this area in order to elucidate the underlying process of hypertension.

Adult↗
PubMed1986

Description of a novel microcomputer program to analyze left ventricular segmental wall motion during normal sinus rhythm and sinus tachycardia.

The authors have written a program to describe left ventricular (LV) regional wall motion (RWM) for a Tektronix 4051 graphic system and an MC68000, 32-bit word based microcomputer utilizing interactive graphics methods. Proper wall motion of 16 defined regions of the LV endocardial perimeter (RAO angiographic views) were computed from the magnitudes of fixed vectors fixed to analogous positions along the LV perimeter from end-diastole to end-systole (Figure 1). It was assumed that (1) LV contraction, tangential to the perimeter, produced RWM at large angles to the direction of contraction, and (2) LV contraction occurred uniformly along the anterolateral and posteromedial perimeters. All motion vectors were computed following digitization of the LV perimeters from projected images of 35-mm cineangiographic frames corrected for linear and nonlinear distortion. Digitization input was accurate to less than 0.3 mm and area computation demonstrated errors of less than 1.5%. A normal group (NG) without coronary artery (CA) disease (N = 31) defined a set of Gaussian distributed referent values for mean WM (magnitude of motion vectors) for all segments. WM amplitudes for the CA disease group (N = 125) demonstrated significant diviation in the areas supplied by occluded or stenosed coronary arteries. Qualitative and quantitative evaluation of the adequacy of coronary circulation and/or collateral vessel development could be made by inspection of WM amplitude computer plots. Proper WM was found to be highly specific for numbers and distribution of coronary arteries diseased.

Cineangiography↗
PubMed1986

Clinical application of time-dependent perimetry: 1. Results in normal subjects.

A perimeter was constructed, using red light-emitting diodes by remodeling a Foerster's perimeter, to test three time-dependent visual functions, ie, double flash resolution (DFR), which is the time threshold of double flash separation, critical flicker fusion frequency (CFF), which is the threshold of flicker separation and perceptual delay (PD), which is the difference in perception between two locations of the visual field. In 10 normal subjects, the DFR and CFF were determined in the center of the field and in 12 points in the paracentral field 10 degrees away from the center. The CFF value was lower in the center than in the paracentral field where no significant difference was found among various meridians. The DFR values showed a marked individual variation. The value was significantly higher in the upper and lower paracentral fields than in the nasal and temporal fields: the DFR in the center of the field showed no significant difference from the DFR in the nasal and temporal paracentral field. The PD was determined between the center and paracentral fields. Individual variation was small and no significant difference was found among the paracentral fields. These results in normal subjects offer a reference for clinical application of the present test methods for various diseases.

Flicker Fusion↗
PubMed1985

Radionuclide imaging for assessment of myocarditis and postmyocarditic state in infant and children. Thallium-201 myocardial imaging and technetium-99m-HSA gated equilibrium ventriculography.

T1-201 myocardial imaging and Tc-99m-HSA gated equilibrium ventriculography were performed in 1 infant and 11 children between 2 months old and 12 years old with myocarditis. The time of first evaluation was between 1 week and 13 months after the onset. Their clinical manifestations were congestive heart failure in 2 patients, pericardial effusion in 2 patients, syncope in 1 patient, convulsions in 1 patient and palpitations in 7 patients. Significant elevation of virus antibody titer was demonstrated in 6 patients. A perfusion defect was observed with T1-201 imaging in 9 of 12 patients with myocarditis. A right ventricular image was observed in 5 patients. A reduced LVEF was present in 4 patients and a reduced RVEF was found in 2 patients. Cardiac catheterization was performed in 8 patients and an endomyocardial biopsy was done in 7. The myocardial specimens revealed postmyocarditic pathological changes upon microscopic evaluation. No coronary artery obstructive or stenotic lesions were observed in these patients. T1-201 myocardial imaging is a useful non-invasive technique for evaluating the cardiac performance and myocardial damage in acute myocarditis and the postmyocarditic state. We conclude that T1-201 uptake of myocardium is dependent upon both regional coronary perfusion and the activity of myocardial cells in patients with myocarditis and in the postmyocarditic state.

Angiography↗