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Biomedical subjects

S Yasui

Publications and source records attributed to S Yasui.

At least 109 records · Page 6Linked to original sources
PubMed1989

Structural changes in airways of rats exposed to nitrogen dioxide intermittently for seven days. Comparison between major bronchi and terminal bronchioles.

Structural changes caused by exposure to NO2 were compared between the largest intrapulmonary bronchi (major bronchi) and the terminal bronchioles. Rats were exposed to 50 ppm NO2 for 5 h a day for 7 consecutive days, and microscopic findings were assessed subjectively and quantitatively. Destruction of airway epithelium was present on Day 1, and the reparative phase was observed between Days 3 and 7. Light microscopy showed that on Day 1, loss of cilia and disintegration of epithelium occurred, and that the latter was worse in major bronchi than in terminal bronchioles; apical projections of Clara cells in terminal bronchioles were lost almost totally. Recovery of epithelium began by Day 3 and cilia by Day 5, and ciliogenesis progressed less promptly in terminal bronchioles. Clara cells did not return to normal during the experiment. Furthermore, a decrease in the airway diameter occurred in peripheral airways along with an increase in mural thickness in terminal bronchioles. Mural inflammation was also seen more conspicuously in terminal bronchioles. Electron microscopy revealed that epithelial cells lost secretory granules on Day 1 and began to repair them by Day 5 in major bronchi and by Day 7 in terminal bronchioles. It is likely that epithelium in terminal bronchioles is not particularly sensitive to NO2 compared with that in major bronchi, but that recovery occurs more promptly in major bronchi than in terminal bronchioles. Mechanisms underlying bronchoconstriction occurring preferentially in peripheral airways are also discussed.

Animals↗
PubMed1989

Assessment of right ventricular overload in patients with chronic pulmonary disease by 12-lead electrocardiography, vectorcardiography, and body surface electrocardiographic mapping.

Twenty-eight patients with chronic pulmonary diseases were examined with standard 12-lead electrocardiogram (ECG), vectorcardiogram (VCG), and body surface ECG mapping (MAP). The electrocardiographic findings were compared with results of 99 mTc radionuclide right ventriculography or T1-201 myocardial scintigraphy. In a stepwise multiple regression analysis between the electrocardiographic parameters and right ventricular ejection fraction, only the amplitude of the negative P wave in V2 (r = 0.69), the posterior force of P loop in VCG (r = 0.71), and the size of -2SD area at 50 msec QRS potential departure map (r = 0.55) were selected as the parameters in standard ECG, VCG, and MAP, respectively. On the radionuclide ventriculography and myocardial scintigraphy, 14 patients were judged to have right ventricular overload. The criteria by VCG, and MAP had better sensitivity and specificity for right ventricle overload than those by 12-lead ECG. VCG criteria of Chou et al had sensitivity of 93% and specificity of 71%. MAP criteria, departure index of F3 or F4 less than or equal to -2, had sensitivity of 86% and specificity of 79%. The electrocardiographic findings by standard 12-lead ECG, VCG and body surface ECG mapping are useful parameters for the noninvasive detection of right ventricular overload in patients with chronic pulmonary diseases.

Chronic Disease↗
PubMed1989

The correlation of the treadmill exercise test with cardiac hemodynamics in patients with previous myocardial infarction.

The correlation between the treadmill exercise test results and the hemodynamic data of 152 patients with previous myocardial infarction were investigated. The patients were classified into 4 groups as follows: H1 left ventricular end-diastolic pressure (LVEDP) less than or equal to 12 mmHg and cardiac index (CI) greater than or equal to 3.0 L/min/m2; H2 LVEDP greater than 12 mmHg and CI greater than or equal to 3.0 L/min/m2; H3 LVEDP less than or equal to 12 mmHg and CI less than 3.0 L/min/m2; and H4 LVEDP greater than 12 mmHg and CI less than 3.0 L/min/m2. The duration of the exercise was significantly shortened for group H4 than group H1 (p less than 0.01). The maximal ST segment elevation (mSTe) was significantly increased for group H3 and group H4, versus group H1 (p less than 0.05). The number of ST segment elevations and mSTe/maximal heart rate were significantly increased for group H3 (p less than 0.05) and group H4 (p less than 0.01) versus group H1. The incidence of exercise-induced premature ventricular contractions (PVCs) was significantly increased in group H3 and group H4, versus group H1 (p less than 0.05). There were no significant differences in the maximal heart rate, double product, and ST segment depression among the 4 groups. Our data indicate that the groups with impaired left ventricular functions tend to decrease the duration of the exercise and to increase ST segment elevation and PVC frequencies during exercise.

Adult↗
PubMed1989

Spatial distribution of exercise-induced ST-segment depression and U-wave inversion in identifying the ischemic site in patients with coronary artery disease.

Eighty-seven unipolar electrocardiograms were simultaneously recorded before and after symptom-limited treadmill exercise in 75 patients with coronary artery narrowing (greater than equal to 70%) and without previous myocardial infarction. Body surface distributions of ST segment depression were divided into 3 types; upper, lower, and diffuse types. Body surface distributions of U-wave inversion were divided into 2 types; upper, and lower types. These distribution patterns were compared with the location of ischemia determined by T1-201 exercise myocardial perfusion imaging. For ST-segment depression, a considerable number of patients had diffuse-type ST depression, whether the site of ischemia was anterior (22/32, 69%), inferior (18/27, 67%) or both (5/5, 100%). However, upper-type ST depression was associated with anterior ischemia, and lower-type ST depression, with inferior ischemia. The sensitivity and specificity of the spatial distribution of ST depression in identifying the myocardial ischemic site were 27% and 95% for anterior ischemia. The sensitivity and specificity of the spatial distribution of St depression in identifying the myocardial ischemic site were 27% and 95% for anterior ischemia respectively, and 28% and 88% for inferior ischemia, respectively. The incidence of U-wave inversion was moderate (29/75, 39%), but the distribution pattern was specific for the site of ischemia; upper-type U inversion associated with anterior ischemia, and lower type with inferior ischemia. The sensitivity and specificity were 59% and 100% for anterior ischemia respectively, and 22% and 100% for inferior ischemia respectively. By a combination of ST-depression and U-inversion, the sensitivity and specificity were 78% and 95% for anterior ischemia, and 44% and 88% for inferior ischemia. Body surface electrocardiographic mapping provided important information in the non-invasive diagnosis of the site of myocardial ischemia.

Adult↗
PubMed1989

Relationship of thallium-201 defect and left ventricular function after dipyridamole infusion.

Tl-201 imaging and first-pass radionuclide ventriculography (RNV) by 4 min infusion of 0.56 mg/kg dipyridamole were performed on 22 patients with coronary artery disease in order to know the relationship of myocardial perfusion and left ventricular function after dipyridamole-infusion, and thereby to define whether Tl-201 defect with dipyridamole could imply myocardial ischemia. Initial and delayed Tl-201 images were divided into anterior, apical, and infero-posterior segments, and segmental perfusion defects were categorized as reversible, fixed and no defect. RNV on the 30-degree right anterior oblique view was also divided into anterior, apical, and infero-posterior wall to be evaluated for regional wall motion by a 5 point score before and after dipyridamole. Changes in left ventricular ejection fraction (LVEF) with dipyridamole were also calculated. Normal responses of regional wall motion and LVEF to dipyridamole were established from the data of 14 normal subjects. Reversible defects were closely associated (69%) with an abnormal response of regional wall motion (score decrease of 1 or more after dipyridamole). Both fixed defects and no defects showed little association with abnormal response of regional wall motion. Moreover, 77% of the patients having reversible-defect segment showed an abnormal response of LVEF (reduction of 3% or more following dipyridamole). However, patients without reversible defect did not show an abnormal response to dipyridamole. These results suggest that dipyridamole-induced Tl-201 defects represent a myocardial ischemia which causes a reduction of ventricular function.

Adult↗
PubMed1989

[The effect of foamy alveolar macrophages presented in bleomycin-injured rat lungs in pulmonary fibrosis].

Foamy alveolar macrophages (FAM) are observed in lungs injured by Bleomycin (BLM), but their relation to pulmonary fibrosis is not clearly understood. We purified FAM from BLM-instilled rat lungs by density gradient centrifugation on Percoll, and studied the effect of FAM on pulmonary fibrosis. The cells lavaged from the rat lungs 14 days after the administration of BLM (B) or saline (S), were applied on Percoll. After centrifugation, the cells layered on each interface were collected and named as SI, SII, SIII, and BI, BII, BIII in order of gravity. The BI layer included 8.5% of unfractionated cells (U). These BI cells were viable (88%), significantly larger than the others, nonspecific esterase positive cells, and included much ferritin and lysozyme, and were morphologically identified as alveolar macrophages (AM). Therefore, we called the BI cells FAM. We estimated the capacity of FAM (2.5 X 10(5] to synthesize DNA (3H-thymidine uptake) and RNA (3H-uridine uptake), and the activities of silica-stimulated FAM to cause proliferation of mouse thymocytes (IL-1 activity) and rat lung fibroblasts (FP activity), and to produce PGE2. FAM has a lower mitogenic activity but did not have been protein synthetic activity as compared with the others. Silica-stimulated FAM released less IL-1 than BII or BIII, and induced less fibroblast growth than BII, but induced as much as BIII, possibly because of the increased capacity of BIII cells to produce PGE2, which is known to inhibit fibroblast growth. In this way, FAM were considered to be "already activated" rather than "highly activated" cells, but the presence of FAM suggested that smaller or denser AM might receive bleomycin stimulation and release fibrogenic mediators (IL-1 or MDGF) into the alveolar spaces during FAM formation, and that AM might participate in the fibrogenic responses.

Animals↗
PubMed1989

Development and clinical application of DNA probe specific for Peptostreptococcus micros.

P. micros is thought to be an important pathogen in the etiology of certain inflammatory lesions, however, the role of this microorganism is uncertain due to the lack of rapid and reliable method to identify this species. The purpose of this study was to develop a DNA probe specific for the detection of P. micros in order to evaluate its prevalence in oral infectious lesions. The whole genomic DNA from P. micros was partially digested and inserted into the vector pUC 13. Four recombinant clones were selected, purified and screened against reference strains of Peptostreptococcus species to check the species specificity and then applied to clinical isolates. The sensitivity and specificity of the DNA probe for P. micros was 99.2% and 100%, respectively. P. micros could be detected in 7.2% of subgingival dental plaques from the patients with adult periodontitis and in 16.1% of the endodontic lesions with periapical pathosis. In the endodontic lesions, there was a good correlation between the clinical symptoms and the presence of P. micros. These data strongly suggested that the DNA probe can be useful in the detection of P. micros and that this microorganism is important in certain periodontal and endodontic lesions.

Aggressive Periodontitis↗
PubMed1989

[Enhancement of enamel crystallinity with gel method during orthodontic treatment. The 1st report: Application of electron probe X-ray microanalyser].

This paper is to review the gel method of strengthening tooth enamel substance around bonded brackets and morphological observations and elemental analyses of the chopped cross section of the three below-mentioned groups were carried out by electron probe X-ray microanalyser (EPMA) for a relative review. Group I: bracket-bonded extracted tooth enamel in application of the silica-hydro gel method. Group II: bracket-bonded extracted tooth enamel in application of the gelatin gel method. Group III: bracket-bonded extracted tooth enamel in application of neither method. The results obtained were as follows: 1) As a result of making morphological observations through secondary electron image and back scattered electron image, the adhesive condition of the brackets and the state of the chopped cross sections were favorable and these combined observation proved effective as a supplementary method of elemental analysis. 2) Through qualitative analyses, Ca, P, F, O, Na, Mg and Cl were recognized as content elements on the experimental side (the non-bracket side) as well as on the control side (the bracket side) from group I through III. 3) In making ultrahigh-speed wide-area surface analyses (elemental concentration map), the incorporation of F was recognized from enamel cuticle to approximately 200 microns in group I and to 50-100 microns in group II, and the distribution of Ca was totally consistent, and P showed the slight downward trend from enamel cuticle to dentoenamel junction. 4) The incorporation of F was acknowledged to be until 150-200 microns on the experimental side of group I and to be until 80 microns on the experimental side of group II by line analyses. 5) As regards F on the experimental and the control side in group I as well as in group II through a quantitative analysis, the experimental side clearly revealed a high concentration of F and acknowledged 1% level to be a significant distinction. From the foregoing results through the electron probe X-ray microanalyser, strengthening tooth enamel substance in vitro by application of the gel method proved to be effective, and the silica-hydro gel method was indicated to be superior to the gelatin gel method.

Dental Bonding↗
PubMed1989

[The study of the lung accumulation of I-123 IMP by the broncho-alveolar lavage].

We studied the accumulated portion and the movement of I-123 IMP in the lung. Ten subjects were studied. They were four patients with fibrosing lung disease, two with lung cancer, and four with other lung disease. They underwent the broncho-alveolar lavage (BAL) for the diagnosis of their disease. 1.5 mCi of I-123 IMP was injected into the ante-cubital vein. The BAL examination was carried out about 40 minutes after the injection of I-123 IMP. The subjects' blood was sampled at the same time. The total BAL liquid (BAL-T) was divided into the fluid component (BAL-F) and the cell component (BAL-C) by centrifugation. The radioactivities in BAL-T, BAL-F, BAL-C, and serum (B-S) were measured by the well-counter. The average of BAL-T/B-S, BAL-F/B-S and BAL-C/B-S were 6.86, 4.26 and 2.71 respectively. It was confirmed that I-123 IMP was transported from the pulmonary capillary to the alveolar space and was taken up by the alveolar cells. It was considered that the analysis of the I-123 IMP release from the lung showed not only the endothelial cell uptake function but also the interstitial and material cells' amine transport and uptake function.

Aged↗
PubMed1989

[Detection of coronary artery disease by exercise radionuclide ventriculography: using sector analysis].

Exercise first-pass radionuclide ventriculography was performed on 65 patients with coronary artery disease (CAD) and 18 control subjects with normal coronary artery, Left ventricle (LV) was divided into 5 sectors in radial, and volume curves were generated for whole LV and each sector for estimating LVEF and time to end systole (TES). The differences of TES between whole LV and each sector were calculated and these 5 differences were averaged (Variation of TES). We defined this Variation of TES as an index of LV asynchrony, and used for detection of CAD. The overall sensitivity and specificity for identifying CAD were 63% and 83% (LVEF during exercise), 51% and 83% (delta LVEF). Variation of TES during exercise had a sensitivity and a specificity of 88% and 83%, and was more sensitive than both LVEF during exercise and delta LVEF (p less than 0.01). In conclusion, Variation of TES was a good marker of LV asynchrony and useful for the detection of CAD.

Coronary Disease↗
PubMed1988

Measurement of DC and AC spectral sensitivities of retinal horizontal cells by "voltage clamp by light".

The method of "voltage clamp by light" was applied to measure spectral sensitivities of second-order visual neurons, namely L- and R/G-type horizontal cells in the carp retina. The present equipment employs (i) a ceramic photomodulator to facilitate a fast servomechanical control of retinal illuminance, (ii) an electronic circuit to compensate for the synaptic transmission delay, and (iii) a manual selection switch for the system to operate on negative feedback for either depolarizing or hyperpolarizing responses to light. These features allowed us to determine quickly and simultaneously both DC and AC spectral sensitivities, although the AC case was examined only at 1 Hz in this report. In L-type cells, the AC spectral sensitivity was similar in shape to the DC result. These sensitivity curves differed from microphotospectrometric absorption of red-sensitive cones: in L-type cells at both ends of the visible spectrum and in R/G units with deep-red light.

Animals↗
PubMed1988

Local conduction delay causes R-wave amplitude increase in patients with effort angina.

Eighty-seven unipolar electrocardiograms distributed over the entire thorax were simulataneously recorded before and after treadmill exercise in 43 patients. Exercise-induced R-wave amplitude change (delta R) and peak R time (time from the onset of QRS to the peak of R wave), were calculated for each lead. The maximal delta R of 87 leads was designated as the max delta R. After exercise, regional delay of peak R time (greater than or equal to 10 msec) on the chest was observed in 13 patients. These patients had significantly higher max delta R than those without such regional peak R time delay (0.71 +/- 0.31mV vs. 0.33 +/- 0.20mV, p less than 0.01). In each case, the site of peak R time delay was almost the same as the site of max delta R. There was no significant difference in the peak heart rate, rise of the systolic blood pressure (delta BPs) during exercise or extent of ischemic ST depression between patients with and without peak R time delay. We concluded that ventricular condition delay plays an important role in the increase of R-wave amplitude after exercise in patients with effort angina pectoris.

Adult↗
PubMed1988

Diagnosis of right ventricular involvement in chronic inferior myocardial infarction by means of body surface QRS changes.

ST segment elevation in right precordial leads is thought to be good predictor of right ventricular involvement in patients with acute inferior myocardial infarction. This view, however, is rapidly disappearing. Therefore, using QRS changes in body surface potential maps in the chronic phase, we have attempted to differentiate patients with or without right ventricular involvement. Thirty patients with chronic inferior myocardial infarction (2 or more months after onset) were studied, in whom 87 unipolar ECGs and right ventriculograms were recorded. The patients were then divided into three groups depending on the locations of their abnormal QRS potentials (-2SD area) exceeding the normal range (mean -2SD). In group A, the -2SD area was located predominantly on the right inferior chest, in group B on the left inferior chest, and in group N on both the right and left inferior chests equally. The results showed that group A had a lower right ventricular ejection fraction (RVEF) compared with group B (A, 40 +/- 7%; B, 53 +/- 10%; p less than .001), while there was no difference in left ventricular ejection fraction between the two groups (49 +/- 11% and 49 +/- 11%, respectively). Moreover, right ventricular asynergy occurred in 14 of the 18 patients (78%) of group A but in only one of the 10 patients (10%) of group B. Group N was presumed to be intermediate between groups A and B.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

The effect of cigarette smoke on bleomycin-induced pulmonary fibrosis in hamsters.

To investigate the effect of cigarette smoke on the development of bleomycin (BLM)-induced pulmonary fibrosis in hamsters, four experimental groups were studied: a control group (C), a cigarette smoke-inhaled group (T), a BLM-administered group (B), and a cigarette smoke-inhaled plus BLM-administered group (TB). Groups T and TB were exposed to sidestream smoke of cigarettes for 30 min/day, 5 days/wk. Groups B and TB were administered 0.5 mg BLM hydrochloride per 100 g body weight endotracheally once on day 30 (Day 0) after housing start. Quantitative morphometry of the lungs revealed that Group TB showed less lung fibrotic change compared with Group B, but based on qualitative observation, the fibrotic lesions of Group TB were intermingled with slight emphysematous changes. Neutrophils in bronchoalveolar lavage fluid were remarkably increased in both the groups, with a peak on Day 1, but the increase in Group TB lasted longer. Alveolar macrophages were increased in both smoking groups (T and TB) compared to the non-smoking groups (C and B). These results suggest that cigarette smoke reduces BLM-induced lung fibrotic changes; however, it simultaneously causes derangement of alveolar architecture. The persistence of increased neutrophils in the early phase after BLM accompanied by exposure to cigarette smoke may play an important role in the mechanism by which smoke ameliorates the effect of BLM.

Animals↗
PubMed1988

Relationship between late potentials and left ventricular function in patients with coronary artery disease.

We examined the relationship between late potentials and left ventricular function from a hemodynamic point of view in 50 patients with prior myocardial infarction. Late potentials were found in 15 (30%) of 50 patients. A left ventricular aneurysm was found in 28 patients. Late potentials were detected in 14 (50%) of 28 patients with the aneurysm but in 1 (5%) of 22 patients without it (p less than 0.01). In the 50 patients, a hemodynamic data from the late potential positive group (n = 15) were compared to those from the late potential negative group (n = 35). The late potential positive group had a significantly lower ejection fraction, cardiac index and stroke volume than the late potential negative group. We further studied the 28 patients with left ventricular aneurysm in a similar way. The cardiac index and stroke volume were also significantly lower in the late potential positive group. The ejection fraction tended to be lower in the late potential positive group. These results suggest that left ventricular function and left ventricular aneurysm are among the factors that influence the development of late potentials.

Adult↗
PubMed1988

Clinical significance of body surface isochrone maps for predicting ventricular arrhythmias in patients with previous myocardial infarction.

To investigate the utility of body surface isochrone maps for estimating ventricular arrhythmias in patients with previous myocardial infarction, we compared findings of body surface isochrone maps with those of signal-averaged electrocardiograms (SAECGs) and an incidence of ventricular tachycardia (VT). Body surface isochrone mapping was performed in 50 patients with previous myocardial infarction. Eighty-seven unipolar electrocardiograms distributed over the patient's anterior chest and back were recorded simultaneously. For each lead, the activation time was measured as the duration from the onset of QRS to the peak of the R wave. SAECGs were recorded in the same patients to detect late potential (LP) which was considered to last more than 30 msec. Activation delay on isochrone maps (D) was found in 31 of 50 patients. The group D+ had a lower ejection fraction and higher incidence of VT (8/31 (25.8%) vs. 1/19 (5.3%)) and LP (13/31 (41.9%) vs. 2/19 (10.5%)) than the group D-. There were four patients with sustained VT who had both D and LP. For predicting VT, D has a sensitivity of 88.9% and a specificity of 43.8%. It was decided that abnormal delay on body surface isochrone maps indicates slow conduction of the surviving myocardium and is related to the occurrence of ventricular arrhythmias. We concluded that body surface isochrone maps can be useful in predicting life-threatening arrhythmias in patients with previous myocardial infarction.

Aged↗
PubMed1988

Bleomycin-stimulated hamster alveolar macrophages release interleukin-1.

The capacity of alveolar macrophages (AM) of bleomycin-instilled hamsters to proliferate mouse thymocytes (interleukin-1 activity) and hamster fibroblasts (fibroblast proliferation (FP) activity was studied. Using bleomycin-instilled hamsters, the FP activity of AM culture supernatants was increased significantly on days 1, 5, and 10 after instillation of bleomycin. The interleukin-1 (IL-1) activity, however, was increased significantly on day 1 only as compared with saline-treated hamsters. Next, normal AM were stimulated in vitro by bleomycin. After being fractionated by chromatography, their culture supernatant showed IL-1 activity, which also indicated FP activity. These results suggest that bleomycin directly stimulates AM to release IL-1 in the fibrogenic responses.

Animals↗