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Biomedical subjects

S Yasui

Publications and source records attributed to S Yasui.

At least 55 records · Page 3Linked to original sources
PubMed1993

Effects of anti-mouse EGF antiserum on prenatal lung development in fetal mice.

To clarify the precise role of epidermal growth factor (EGF) on fetal lung development, rabbit anti-mouse EGF (anti-mEGF) antiserum was administered to pregnant mice from days 10 to 17 during late gestation. Control mice were administered either normal rabbit serum (NRS) or physiological saline (PS). Serum EGF was not detected in fetuses from anti-mEGF antiserum treated mothers, but the level in NRS treated control animals was 4.73 +/- 0.66 ng/mL. One day prior to birth, the fetuses were removed and their body and lung weights were measured. There was no difference between body weights and lung weights of anti-mEGF antiserum treated animals and NRS-treated control animals. On light microscopic morphometry, there was no obvious difference between pulmonary architecture of anti-mEGF antiserum treated animals and NRS treated control animals. On transmission electron microscopy, osmiophillic lamellar inclusion bodies were less prominent in the type II epithelial cells in anti-mEGF antiserum treated animals. Electron microscopic morphometric study revealed that the osmiophillic lamellar inclusion bodies in type II epithelial cells of anti-mEGF antiserum treated animals were fewer in number and had decreased area fraction. These findings support the previous finding that EGF promotes epithelial cell differentiation of the fetal lung without affecting body weight and lung weight.

Animals↗
PubMed1993

Changes in local cerebral glucose utilization and dopamine metabolism in the rat brain following acute administration of haloperidol.

The effects of acute administration of haloperidol on local cerebral glucose utilization (LCGU) in 26 discrete regions of the rat brain were examined by the quantitative autoradiographic [14C] 2-deoxy-D-glucose technique and compared with the changes in dopamine (DA) metabolism in 13 brain regions examined by a high performance liquid chromatographic assay. A moderate dose (0.25 mg/kg) of acute haloperidol significantly reduced LCGU in a few brain regions; a high dose (1.0 mg/kg) reduced LCGU in 11 regions including the prefrontal cortex, thalamus and other subcortical structures, but not in the caudate putamen or accumbens nucleus. However, the levels of DA metabolite in the caudate-putamen, accumbens nucleus, prefrontal cortex, and medial thalamus were strikingly elevated with both doses of haloperidol. Thus, the changes in LCGU did not parallel presynaptic DA metabolism in terms of direction or distribution, and they might represent mainly the activities of postsynaptic sites.

Animals↗
PubMed1993

Distribution of Porphyromonas gingivalis in adult periodontitis patients.

Porphyromonas gingivalis (P. gingivalis) is considered to be a pathogenic factor in adult or rapidly progressive periodontitis. The purpose of this study was to evaluate the distribution of P. gingivalis in the dentition of adult periodontitis patients using a nonradioactive DNA probe, and to compare the presence of P. gingivalis with clinical parameters. Twelve adult periodontitis patients were examined. Subgingival plaque samples were taken from 4 sites of all the remaining teeth using a paper point. At the same time, probing depth and bleeding on probing (BOP) were also recorded. Plaque samples were investigated using a whole genomic DNA probe from P. gingivalis (ATCC 33277) modified with bisulfite. The detection, percentage and amounts of P. gingivalis present were statistically compared with probing depth and BOP in each patient. P. gingivalis was detected in all patients examined. The detection percentage was 35% of all sample sites. When the probing depth was over 4 mm or BOP was positive, the detection percentage of P. gingivalis significantly increased (P < 0.01). As more P. gingivalis was identified, the percentage of sites with deep probing depth or that were BOP positive increased significantly (P < 0.01). However, P. gingivalis was also detected in clinically healthy sites, and P. gingivalis negative sites with deep probing depth or that were BOP positive existed in the same patient. These results indicate that P. gingivalis play an important role, but is not the only microorganism responsible for adult periodontitis.

Adult↗
PubMed1993

Lesions of the arytenoid region in a patient with exertional dyspnoea.

A 63 year old woman presented with a 3 year history of exertional dyspnoea. Spirometry suggested extrathoracic airway obstruction (decreased inspiratory flow and saw-tooth pattern of flow-volume curves), and bronchoscopy revealed structural lesions and a trembling motion in the arytenoid region, causing upper airway obstruction on forced respiratory efforts. As there were no abnormal findings other than the lesions, the exertional dyspnoea was probably caused by impaired movement of the arytenoid region.

Dyspnea↗
PubMed1992

A case of pediatric cardiomyopathy with severely restrictive physiology.

A rare case of a 6-year-old male with idiopathic familial cardiomyopathy manifesting severely restrictive physiology is reported. The patient showed congestive heart failure with dilatation of both atria with a normal ventricular cavity. A square-root configuration was revealed in the ventricular pressure tracings. His elder brother had died of hypertrophic cardiomyopathy at the age of 3 years. Endomyocardial biopsy disclosed marked disorganization of muscle bundles with hypertrophy of the myocytes and interstitial fibrosis. The patient died suddenly during hospitalization. Autopsy revealed diffuse hypertrophy of both the ventricular walls and the ventricular septum with extensive myocardial disorganization and interstitial fibrosis. These advanced myopathic changes in the myocardium may have been related to the restrictive physiology in this case.

Bundle-Branch Block↗
PubMed1992

On the square root intensity coding at the level of cone photoreceptors.

In psychophysics as well as in sensory physiology, the response amplitude R is often a power function of the stimulus intensity S over a wide range of S (i.e. R = aSk; a = constant). In vision, there is a recent report that such a power relationship ("square root intensity coding" if k = 0.5) may arise as early as at the cone photoreceptor level if the stimulus is a narrow slit of light. A simple model is presented here to account for this finding: strong electrical coupling with several neighboring cones can act to expand the dynamic range of the impaled cone in such a way as to produce a square root coding region for the responses to fine visual objects such as small spots and narrow slits.

Dose-Response Relationship, Radiation↗
PubMed1992

Lateral flagella of vibrios: serological classification and genetical similarity.

Lateral (L-) flagella-having vibrios were classified into 13 H-serogroups (flagellar antigen serogroups) by means of H-agglutination test. Vibrio parahaemolyticus was classified into 3 serogroups, HL1 to 3. V. alginolyticus and V. harveyi were classified into 5 and 3 serogroups, respectively, but 2 of those were serogroups common to the both species. V. fluvialis and V. furnissii constituted a same serogroup, HL8. Cross-reactivity between each serogroup was not observed in H-agglutination test, although some cross-reactivity was observed in gel diffusion test. Furthermore, similarity of DNA sequence of L-flagellar structure gene was demonstrated by dot blot hybridization test with a DNA probe of HL2 L-flagellar gene fragment. These results suggest conservation of DNA sequence of the L-flagellar gene of vibrios.

Cross Reactions↗
PubMed1992

Dipyridamole electrocardiography test for the assessment of the severity of coronary artery disease.

The purpose of this study was to investigate the relationship of dipyridamole-induced ST changes to the severity of coronary artery disease. The subjects were 100 patients without myocardial infarction who underwent coronary arteriography for the diagnosis of coronary artery disease. The dipyridamole injection test (D) (0.568 mg/kg/4 min), and symptom-limited treadmill exercise test (T) were performed separately. Body surface electrocardiographic mapping of 87 leads was performed in both tests. The incidences of significant ST depression greater than or equal to 0.10 mV, number of leads showing significant ST depression (nST) and the maximal voltage of ST depression (maxST) in D and T were compared to the number of diseased coronary arteries. In patients without significant coronary stenosis (0VD group), the incidence of ST depression in the dipyridamole test was significantly lower than that in the treadmill test (D 9% vs T 47%, p less than 0.01). While, in one vessel disease (1VD), two vessel disease (2VD), and three vessel disease (3VD) groups, there was no significant difference in the incidence of ST depression between the dipyridamole test and the treadmill test (in 1VD, D 44% vs. T 65%; in 2VD, D 67% vs. T 93%; and in 3VD, D 93% vs. T 96%). In the dipyridamole test, nST was 0.6 +/- 2.4 in 0VD, 4.5 +/- 6.9 in 1VD, 4.1 +/- 4.5 in 2VD, and 10.6 +/- 8.1 in 3VD. Significant differences were found between 0VD and 1VD (P less than 0.05), 0VD and 3VD (P less than 0.01), 1VD and 3VD (P less than 0.01), and 2VD and 3VD (p less than 0.01). The maxST in the dipyridamole test was 0.02 +/- 0.04 mV in 0VD, 0.10 +/- 0.12 mV in 1VD, 0.13 +/- 0.11 mV in 2VD, and 0.22 +/- 0.11 mV in 3VD. Significant differences were found between 0VD and 1VD (p less than 0.01), 0VD and 2VD (p less than 0.01), 0VD and 3VD (p less than 0.01), 1VD and 3VD (p less than 0.01), and 2VD and 3VD (P less than 0.01). For the diagnosis of 3VD, the dipyridamole ECG test had as high a sensitivity (93% vs 96%), higher specificity (68% vs 38%, p less than 0.01), and higher predictive accuracy (75% vs 54%, p less than 0.01) than the treadmill test.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1992

Dipyridamole electrocardiography test for the detection of severe coronary artery stenoses.

To investigate the relationship between dipyridamole-induced ST depression and the severity of coronary artery stenosis, the dipyridamole injection test (D) at 0.568 mg/kg/4 min, and the symptom limited treadmill exercise test (T) were performed separately in 16 normal volunteers and 167 patients who underwent coronary arteriography [91 patients without myocardial infarction (non-MI group) and 76 patients with previous myocardial infarction (MI group)]. Standard 12-lead electrocardiogram and body surface mapping of 87 leads were recorded in both tests. None of the normal volunteers had significant ST depression (greater than or equal to 0.10 mV) in D or T. Regarding the non-MI group, D had as high an incidence of ST depression as T (83% vs 93%) in patients with maximal coronary stenosis greater than or equal to 90%, while in those with maximum coronary stenosis less than 90%, D had a lower incidence of ST depression than T (16% vs 48%, p less than 0.01). For the MI group, the incidence of ST depression was compared to the maximal coronary artery stenosis supplying the non-infarcted area. In patients with maximal coronary artery stenosis greater than or equal to 90%, D had as high an incidence of ST depression as T (71% vs 64%). While, D had a lower incidence of ST depression than T (19% vs 35%, p less than 0.05) in those with maximum coronary artery stenosis less than 90%. For the diagnosis of coronary artery stenosis of greater than or equal to 90%, D had as high sensitivity (non-MI group, 82% vs 93%; MI group, 71% vs 64%) and higher specificity (non-MI group, 84% vs 52%, p less than 0.01; MI group, 81% vs 65%, p less than 0.05) compared with T. This study demonstrated that dipyridamole ECG is a sensitive and specific test to detect severe coronary artery stenosis.

Adult↗
PubMed1992

Clinical application of a newly developed surveying system for designing and fabricating removable partial dentures.

In this paper, some problems in commercially available surveying systems were discussed, and a clinical technique for designing and fabricating clasps by using an improved 'Digital Surveyor' and a computer system were presented. This system has the advantages as follows: (1) morphological factors on abutment teeth could be measured and evaluated using the improved 'Digital Surveyor' and its accessories set, (2) clasps providing with proper mechanical properties according to various conditions in the mouth could be designed and fabricated precisely and easily. It became clear that conventional surveying methods involved empirical rules should be re-examined and replaced by the more rational surveying method like this system.

Computer-Aided Design↗
PubMed1992

Effects of heat treatment on mechanical properties of base metal wrought wire clasps.

The purpose of this study is to determine the effects of heat treatment and soldering on the change of shape and mechanical properties of cobalt-chromium-nickel alloy wrought wire clasps. The change of distance between the tips of the clasp arm was measured and mechanical properties were examined using the bending test. The following results were obtained. 1) By heat treatment at 500-700 degrees C for 10 minutes, bending rigidity and deflection at the proportional limit of the clasp arm increased significantly (p < 0.01), while permanent deformation after the bending test decreased considerably (p < 0.01). Concerning the deformation of clasp arms by heating, the distance between clasp tips increased remarkably above 500 degrees C (p < 0.01). 2) These mechanical properties of clasp arms were improved both by electric resistance soldering with silver solder and by heat treatment at 500 degrees C for 10 minutes after soldering. From these results, it was concluded that electric resistance soldering and adequate heat treatment were very effective to improve the mechanical properties of the clasp arm, especially to increase the deflection at the proportional limit and reduce the permanent deformation.

Chemical Phenomena↗
PubMed1991

Dilatation of the left ventricular cavity on dipyridamole thallium-201 imaging: a new marker of triple-vessel disease.

To investigate the significance and mechanism of dilatation of the left ventricular cavity on dipyridamole thallium-201 imaging, we performed both dipyridamole thallium-201 imaging and dipyridamole radionuclide angiography on 83 patients with known angiograms. The dipyridamole/delayed ratio of the left ventricular dimension from the thallium-201 image was defined as the left ventricular dilatation ratio (LVDR). An LVDR greater than the mean + two standard deviations in patients without coronary artery disease was defined as abnormal. Twenty-two of 83 patients showed an abnormal LVDR, and 18 of the 22 patients (82%) had triple-vessel disease. By defect and washout analysis, the sensitivity and specificity for correctly identifying the patients as having triple-vessel disease was 72% and 76%, respectively, whereas LVDR had a sensitivity of 72% and a specificity of 93%. When LVDR was used in combination with the defect and washout criteria, sensitivity increased to 84% without a loss of specificity. In those 22 patients with abnormal LVDRs, end-diastolic volume measured by radionuclide angiography did not change after dipyridamole infusion. Dilatation of the left ventricular cavity on dipyridamole thallium-201 imaging reflected relative subendocardial hypoperfusion induced by dipyridamole rather than actual chamber enlargement. The LVDR was moderately sensitive and highly specific for triple-vessel disease and provided complementary information to dipyridamole thallium-201 imaging.

Adult↗
PubMed1991

Signal-averaged body surface mapping for the assessment of low-amplitude potentials. Detailed maps during early ventricular activation in normal subjects.

Body surface isopotential maps around early ventricular activation were investigated in 30 normal subjects by the use of the authors' signal-averaged body surface mapping system. The number of beats averaged was 96-154 (mean, 127). Two distinct patterns were recognized in the appearance of a maximum at the onset of ventricular activation: the maximum in the first type (n = 16) was located on the right anterior chest; the maximum in the second type (n = 14) was on the central or left anterior chest. The site of the earliest ventricular activation was considered to be different in each of these types. During early ventricular activation, 25 subjects (83%) had two minima: one was on the left lateral chest and the other was on the left back. The two minima probably reflect two different receding activation fronts in the ventricles. The data in the present study are important to the understanding of the early ventricular activation process, as well as the diagnosis of heart diseases in which this process is disturbed.

Adolescent↗
PubMed1991

Changes of lung surfactant and pressure-volume curve in bleomycin-induced pulmonary fibrosis.

We investigated whether alveolar surface force increased and participated in the lung pressure-volume relationship in bleomycin-induced pulmonary fibrosis in hamsters and, if so, whether lung surfactant was hampered in the lungs. On the air-filled pressure-volume curve, decreases of lung volume from control level were significantly higher at 3-8 cmH2O pressure on day 10 than on day 30. Because the change of lung tissue elasticity evaluated from the saline-filled pressure-volume curve was equal for the 2 days, the higher decrease of air volume on day 10 was due primarily to contribution of alveolar surface force. Pressure differences between deflation limbs of air-filled and saline-filled pressure-volume curves, which represented net alveolar surface force, were significantly higher at any lung volume between 50 and 90% total lung capacity on day 10, but almost no significance was observed on day 30. Phospholipid concentration in bronchoalveolar lavage fluid significantly decreased on day 10 but had improved by day 30. Analysis of phospholipid species in purified lung surfactant showed decreased fractions of disaturated phosphatidylcholine and phosphatidylglycerol on day 10. Surface-active properties of the surfactant, measured by a modified Wilhelmy balance, were remarkably hampered on day 10, but most of them had improved by day 30. We consider that the quantitative and functional abnormalities of lung surfactant have a part in the aggravation of lung mechanics in the acute phase of pulmonary fibrosis.

Animals↗
PubMed1991

Effect of altered activation sequence on epicardial QRST area and refractory period in dogs.

BACKGROUND: We investigated the effects of activation sequence on cardiac surface QRST areas and refractory periods in experiments on dogs. METHODS AND RESULTS: Right and left ventricular pacings were performed, and the pacing site was altered every 6 minutes. After 4 minutes of a given pacing, 54 unipolar electrograms distributed over the entire cardiac surface were recorded. Next, refractory periods at electrode sites near pacing electrodes were measured. Paired right ventricular/left ventricular (RV/LV) pacing data were obtained six or seven times in each sample. Although the QRST isoarea maps during the two activation orders were qualitatively similar, it was recognized consistently from the right ventricle-left ventricle difference map that leads around the RV free wall had positive values and that leads around the LV free wall and apex had negative values. Compared with the same leads at RV and LV pacing, QRST areas were larger when pacing sites were near the leads. The local QRST areas of individual leads at which we measured local refractory period were consistently larger during drive from proximal pacing sites than during drive from distant pacing sites. Refractory periods were consistently longer during proximal pacing than during distal pacing, and there was a positive correlation between change in local QRST area and change in refractory period (r = 0.64) during altered activation sequence, whereas there was an inverse correlation between change in QRST area and change in refractory period (r = -0.91) during localized myocardial warming. CONCLUSIONS: Both local QRST areas and local refractory periods were dependent on the activation sequence, and there was a positive correlation between QRST areas and refractory periods during various activation sequences compared with localized myocardial warming.

Animals↗
PubMed1991

Coronary artery aneurysm without stenosis in association with Osler-Weber-Rendu disease--a case report.

A fifty-three-year-old woman presented with coronary artery aneurysm in association with Osler-Weber-Rendu disease (hereditary hemorrhagic telangiectasia) manifested also by large pulmonary arteriovenous fistulas. The arterial dye dilution curves were unusually distorted owing to the right-to-left shunts. The coronary artery aneurysm was located in multiple sites but was not accompanied by stenotic lesions. Coronary artery aneurysm without stenosis is a rare pathologic state and has not been previously reported in association with hereditary telangiectasia.

Arteriovenous Fistula↗