Search PubMed⌕ Search

Biomedical subjects

T Yasugi

Publications and source records attributed to T Yasugi.

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

Comparative evaluation of blood and urine analysis as a tool for biological monitoring of n-hexane and toluene.

Blood and urine samples were collected from 57 male Japanese solvent workers [exposed to n-hexane (Hex-A), ethyl acetate, and toluene (Tol-A) at 1.5, 2.3, and 2.3 ppm as GM-TWA, respectively] and also from 20 male nonexposed workers at the end of a 8-h shift, and analyzed for n-hexane (Hex-B) and toluene (Tol-B) in blood, and n-hexane (Hex-U), toluene (Tol-U), 2,5-hexanedione [both with (HD-U/cHYD) and without hydrolysis (HD-U/sHYD)] and hippuric acid (HA-U) in urine. Regression analysis showed that both Hex-B and Tol-B correlated significantly with corresponding exposure to the solvents. Solvents in urine (Hex-U and Tol-U) also correlated with solvents in air but with smaller correlation coefficients than the solvents in blood. Both HD-U/cHYD and HD-U/sHYD showed significant correlation with Hex-A, but HA-U failed to do so with Tol-A. Based on the correlation among biological exposure indicators and solvent concentration in air, sensitivity as an exposure indicator was compared between the solvent in blood and the metabolite in urine in terms of the lowest solvent concentration at which the exposed can be separated (with statistical significance) from the nonexposed (the lowest separation concentration; LSC). The LSC was 3.9 ppm for Hex-B, 1 to 2 ppm for HD-U/sHYD and 10 to 30 ppm for HD-U/cHYD, suggesting that HD-U/sHYD is superior even to Hex-B in detecting low n-hexane exposure; this high sensitivity of HD-U/sHYD is due to the absence of HD-U/sHYD in the urine from the nonexposed.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants, Occupational↗
PubMed1993

Immunohistochemical demonstration of membrane cofactor protein (MCP) of complement in normal and diseased kidney tissues.

The immunohistochemically stained membrane cofactor protein of complement (MCP/CD46), one of the complement regulatory proteins, was up-regulated in some diseased kidney tissues. MCP in diseased kidneys was strongly concentrated along the glomerular capillary walls as well as in the mesangial regions, while MCP in normal kidneys was weakly detected in all glomerular structural cells and in the epithelial cells of tubules. Since the enhanced staining was noted in those areas where depositions of C3b/C3c occurred, ongoing complement reaction might be responsible for the up-regulation of MCP expression. MCP expression may be up-regulated by complement fragments generated during complement activation in glomerulonephritis. Furthermore, anti-MCP staining was stronger in intensity in patients with moderate to massive proteinuria, indicating that up-regulation of MCP expression could be directly correlated to the kidney damage.

Antigens, CD↗
PubMed1993

Recombinant granulocyte-macrophage colony-stimulating factor modulates in vitro function of the peripheral blood mononuclear cells in lipoid nephrosis.

The effect of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) on the in vitro proliferation of peripheral blood lymphocytes (PBL) was evaluated in patients with lipoid nephrosis (LN). The cytokine increased the proliferation of LN PBL in response to phytohemagglutinin (PHA), measured by the [3H]thymidine uptake. The effects were abrogated by antibody against human GM-CSF. We then investigated the effect of GM-CSF on the release of interleukin-1 (IL-1) from peripheral blood monocytes (PBM) in LN patients and normals. In vitro IL-1 production by LN PBM treated with lipopolysaccharide (LPS) was enhanced by coculture with GM-CSF. Potentiation was approximately 2-fold. The immunological identity of the thymocyte comitogenic activity as IL-1 was confirmed by neutralization with a specific rabbit antihuman IL-1 antiserum. Taken together, these observations suggest that one mechanism by which GM-CSF acts to restore immune responses in LN patients may be enhancing the signals which enable activated monocytes/macrophages to secrete IL-1.

Adult↗
PubMed1993

Usefulness of thallium-201 re-injection method for the evaluation of myocardial viability.

Areas of the heart which are supposedly absent of myocardial viability due to persistent thallium defect in exercise thallium myocardial scintigraphy sometimes recover ventricular wall motion through coronary revascularization. To avoid such underestimation of myocardial viability, a "re-injection method" was developed. At the peak of supine ergometer exercise in 51 patients with coronary artery disease, 111 MBq thallium was injected. Conventional exercise and 3 h-delay images were then obtained using single photon emission computed tomography. Subsequently, 55 MBq thallium was injected and a re-injection image was obtained 1 h later. Each image was divided into 12 segments and compared by left ventriculography and coronary angiography. Redistribution was found in 36 patients (71%) on the delayed images and in 44 patients (86%) on either the delayed or the re-injection images (p < 0.05). There were 127 redistribution segments (38%) on the delayed images and 163 (49%) on the re-injection images out of 336 defects on the exercise images (p < 0.001). In normokinetic segments with significant coronary stenosis and in hypokinetic segments, redistribution was found in 42% and 45% of the defects, respectively, on the delayed images, and in 65% and 62% of the defects, respectively, on the re-injection images (p < 0.01). However, no significant differences were observed between the delayed and either the delayed or re-injection images in the akinetic segments. These results suggest that the re-injection method is useful for avoiding underestimation of myocardial viability.

Aged↗
PubMed1993

Assessment of ejection fraction of the right and left ventricles in patients with acute myocardial infarction by magnetic resonance imaging.

Right and left ventricular function in acute myocardial infarction (AMI) was assessed by ECG-gated magnetic resonance imagine (MRI) in 64 patients and 8 volunteers. Five short axis images for intrinsic cardiac long-axis of the left ventricle were obtained at 9 msec and 309 msec after the R wave as end-diastole and end-systole. Right and left ventricular volumes were measured by Simpson's rule. The intraobserver variabilities in right and left ventricular ejection fraction (RVEF: r = 0.94, LVEF: 0.89) were excellent. The interobserver variabilities in RVEF (r = 0.61) and LVEF (r = 0.77) were fair. LVEF, but not RVEF, was significantly reduced in patients with AMI. Among left ventricular dysfunction (LVEF < or = 40%) patients, 50% exhibited right ventricular dysfunction (RVEF < or = 40%). Among patients without left ventricular dysfunction, only 12% exhibited right ventricular dysfunction. In left ventricular and biventricular dysfunction compared with control, the left ventricular end-diastolic volume index increased (65 +/- 10 ml/m2, 68 +/- 12 ml/m2 vs 54 +/- 8 ml/m2), the end-systolic volume index increased (40 +/- 16 ml/m2, 43 +/- 7 ml/m2 vs 18 +/- 1 ml/m2), and the right ventricular end-diastolic volume index decreased (52 +/- 13 ml/m2, 53 +/- 20 ml/m2 vs 65 +/- 8 ml/m2). MRI can thus be used to assess ventricular systolic function. Since patients with left ventricular dysfunction revealed a high incidence of right ventricular dysfunction, an interaction between the left and right ventricles may occur in ventricular dysfunction.

Adult↗
PubMed1993

[Usefulness and safety of dobutamine stress thallium myocardial scintigraphy].

Pharmaceutical stress test is performed for diagnosis of coronary artery disease in patients who can not perform exercise test. We studied whether high dose dobutamine stress test is useful and safe. Subjects consisted of 133 patients (pts) in doubutamine stress test and 45 pts in exercise test. Dobutamine stress test was initiated by 10 micrograms/kg/min, followed by 10 micrograms/kg/min increment every 3 minutes. Maximal doubutamine dose was 40 micrograms/kg/min for 3 minutes. Endpoints of dobutamine stress were as follows: ST depression equal to or more than (> or =) 0.2 mV: 30 pts, > or = 75% predictive maximum heart rate: 20 pts, > or = 20 mmHg systolic blood pressure fallen: 10 pts, 40 micrograms/kg/min for 3 minutes: 10 pts, chest pain: 7 pts, pressure rate product (PRP) > or = 25,000: 1 patient. Side effects of dobutamine stress test were as follows: palpitation: 52%, arrhythmia: 13%, angina and dyspnea: 7%, headache: 6%. These symptoms were disappeared within 2 minutes. One patient, who performed dobutamine test 2 day after PTCA, had myocardial infarction. At peak of dobutamine stress test, systolic blood pressure, heart rate and PRP were increased similar to exercise test. However, diastolic blood pressure was not changed. The concentration at peak of dobutamine was 25.5 +/- 7.8 micrograms/kg/min. The duration of dobutamine stress test was 7.3 +/- 2.3 minutes. The 65 patients (49%) need more than 20 micrograms/kg/min of dobutamine which was maximal loading dose in previous reports. For diagnosis of coronary artery disease, sensitivity was 91% (31/34) and specificity was 70% (7/10). From these data, high dose dobutamine stress test is useful and relatively safe stress method for diagnosis of coronary disease. This stress test would be performed in patients who can not perform exercise test.

Adult↗
PubMed1993

[Usefulness of electrocardiogram gated 99mTc-methoxy isobutyl isonitrile (MIBI) single photon emission computed tomography for detection of wall motion abnormality of left ventricle].

We evaluated whether the newly developed perfusion imaging agent "99mTc-methoxy isobutyl isonitrile (MIBI)" has a possibility to detect wall motion abnormality of left ventricle. Electrocardiogram (ECG) gated single photon emission computed tomography (SPECT) was performed in 6 patients with myocardial infarction (anterior: 3 and inferior: 3). Apical and basal short axis images were selected from each patient and circumferential analysis was performed on end-diastolic (ED) and end-systolic (ES) images respectively. Count in end-diastole (EDC) and count in end-systole (ESC) were obtained, then % (ESC-EDC) and (ESC-EDC)/EDC were calculated. Wall motion of left ventricle was evaluated by either ultrasonic cardiogram or left ventriculography. Left ventricle was divided into anterior, septal, posterior and lateral areas and then each area was divided into apical and basal segments (finally the heart was divided into 8 segments). Of 48 segments, 33 segments showed normal wall motion and 15 segments showed abnormal wall motion: hypokinesis, akinesis and dyskinesis. % (ESC-EDC) was 74.39 +/- 16.85% in segment of normal wall motion and 33.27 +/- 23.56% in segment of abnormal wall motion (p < 0.001). (ESC-EDC)/EDC was 48.67 +/- 13.35% in segment of normal wall motion and 23.33 +/- 18.83% in segment of abnormal wall motion (p < 0.001). From these data, lower limit of % (ESC-EDC) and (ESC-EDC)/EDC in normal wall motion was defined as 40 and 22 respectively: mean -2SD of normal wall motion. Sensitivity of diagnosis of abnormal wall motion was 73% in % (ESC-EDC) and 60% in (ESC-EDC)/EDC (n.s.). Specificity was 94% and 97% (n.s.).(ABSTRACT TRUNCATED AT 250 WORDS)

Electrocardiography↗
PubMed1992

[Pregnancy in Cushing's syndrome].

Pregnancy in cases of Cushing's syndrome is rare. A pregnant patient with Cushing's syndrome due to an adrenal adenoma who was diagnosed in the third trimester is described. She underwent conservative treatment for Cushing's syndrome and delivered a normal infant by Caesarean section. Currently, 121 pregnancies in 97 patients have been reported, but a principle for the treatment of the mother and fetus has not yet been established. We reviewed pregnancy in Cushing's syndrome based on the world literature and evaluated the choice of treatment to take. In the first trimester of pregnancy, therapeutic abortion or surgical treatment, such as adrenalectomy or resection of the pituitary tumor in Cushing's syndrome, is recommended for patients with severe hypercorticism (plasma cortisol > or = 30 micrograms/dl, urinary 17-OHCS > or = 15 mg/day, urinary free cortisol > or = 1000 micrograms/day), while conservative treatment is recommended for patients with mild hypercorticism (plasma cortisol < 30 micrograms/dl, urinary 17-OHCS < 15 mg/day, urinary free cortisol < 1000 micrograms/day). In the second trimester of pregnancy, surgical treatment is recommended for patients with severe hypercorticism, while conservative treatment is recommended for patients with mild hypercorticism. In the third trimester of pregnancy, Caesarean section is recommended for most cases. Drug treatments such as with metyrapone should be limited to patients showing severe hypercorticism or a maternal high risk who have contraindications to surgical treatment.

Adenoma↗
PubMed1992

Altered basal firing pattern and postactivation inhibition of locus coeruleus neurons in spontaneously hypertensive rats.

We compared the spontaneous unit activity and inhibition of impulse activity following antidromic activation (postactivation inhibition, PAI) of locus coeruleus (LC) neurons in spontaneously hypertensive rats (SHR) with those of LC neurons in Wistar-Kyoto rats (WKY). Spontaneous spikes of the LC were analyzed by interspike time histograms. The basal unit activity and variation coefficient of the interspike interval were decreased in SHR. The duration of the PAI which was yielded by antidromic activation from the dorsal noradrenergic bundle was shortened in SHR. These findings suggest that SHR LC neurons possess an altered basal firing pattern and inhibitory mechanism.

Action Potentials↗
PubMed1992

Comparative evaluation of urinalysis and blood analysis as means of detecting exposure to organic solvents at low concentrations.

One hundred and forty-three workers exposed to one or more of toluene, xylene, ethylbenzene, styrene, n-hexane, and methanol at sub-occupational exposure limits were examined for the time-weighted average intensity of exposure by diffusive sampling, and for biological exposure indicators by means of analysis of shift-end blood for the solvent and analysis of shift-end urine for the corresponding metabolite(s). Urinalysis was also performed in 20 nonexposed control men to establish the "background level." Both solvent concentrations in blood and metabolite concentrations in urine correlated significantly with solvent concentrations in air. Comparison of blood analysis and urinalysis as regards sensitivity in identifying low solvent exposure showed that blood analysis is generally superior to urinalysis. It was also noted that estimation of exposure intensity on an individual basis is scarcely possible even with blood analysis. Solvent concentration in whole blood was the same as that in serum in the case of the aromatics, except for styrene. It was higher in blood than in serum in the case of n-hexane, and lower in the cases of styrene and methanol.

Acetates↗
PubMed1992

Formic acid excretion in comparison with methanol excretion in urine of workers occupationally exposed to methanol.

A semiautomated head-space gas chromatographic (GC) method was developed for measuring formic acid in urine. The method consists of heating 1 ml urine sample in a 20-ml air-tight vial in the presence of 1 ml sulfuric acid and 2 ml ethanol at 60 degrees C for 30 min for ethyl esterification and air-liquid equilibrium, followed by automatic injection of 1 ml head-space air into a flame ionization detector GC. The detection limit was 1 mg/l for formic acid. The method was applied to measure formic acid in the shift-end urine samples from 88 workers exposed to methanol at 66.6 ppm (as geometric mean) and in urine samples from 149 nonexposed controls. Methanol concentrations were also determined. Regression analysis showed that urinary formic acid concentrations, as observed or corrected for either creatinine concentration or specific gravity of urine (1.016), correlated significantly with time-weighted average intensities of exposure to methanol vapor. Men excreted significantly more formic acid than women. Comparison with methanol excretion suggested, however, that urinary formic acid is less sensitive than urinary methanol as an indicator of methanol vapor exposure, primarily because the background level for formic acid (26 mg/l as arithmetic mean, or 23 mg/l as geometric mean) is more than ten times higher than the level for methanol (1.9 mg/l as arithmetic mean, or 1.7 mg/l as geometric mean). After theoretical methanol exposure at infinite concentration, the urinary formic acid/methanol ratio should be about 0.4.

Adult↗
PubMed1992

Monitoring of workers exposed to a mixture of toluene, styrene and methanol vapours by means of diffusive air sampling, blood analysis and urinalysis.

Exposure of 34 male workers to combined toluene, styrene and methanol was monitored by personal diffusive sampling of solvent vapours in breathing zone air, analysis of shift-end blood for the 3 solvents and analysis of shift-end urine for hippuric, mandelic and phenylglyoxylic acids and methanol. The exposure of most of the workers was below current occupational exposure limits. Regression analysis showed that a linear correlation exists for each of the 3 solvents between any pairs of the concentrations in air, blood and urine. Namely, toluene, styrene and methanol concentrations in blood obtained at the end of a shift are linearly related to the time-weighted average intensity of exposure to corresponding solvents, and also hippuric, mandelic and phenylglyoxylic acids as well as methanol in shift-end urine. The concentrations of hippuric, mandelic and phenylglyoxylic acids as well as methanol in urine correlated with the respiratory exposure intensity. Comparison of the present results with the exposure--excretion relationship after occupational exposure to the individual solvent showed that no modification in metabolism is induced by the combined exposure when exposure is low, as in the present case.

Air Pollutants, Occupational↗
PubMed1992

Occupational dimethylformamide exposure. 1. Diffusive sampling of dimethylformamide vapor for determination of time-weighted average concentration in air.

A diffusive sampling method with water as absorbent was examined in comparison with 3 conventional methods of diffusive sampling with carbon cloth as absorbent, pumping through National Institute of Occupational Safety and Health (NIOSH) charcoal tubes, and pumping through NIOSH silica gel tubes to measure time-weighted average concentration of dimethylformamide (DMF). DMF vapors of constant concentrations at 3-110 ppm were generated by bubbling air at constant velocities through liquid DMF followed by dilution with fresh air. Both types of diffusive samplers could either absorb or adsorb DMF in proportion to time (0.25-8 h) and concentration (3-58 ppm), except that the DMF adsorbed was below the measurable amount when carbon cloth samplers were exposed at 3 ppm for less than 1 h. When both diffusive samplers were loaded with DMF and kept in fresh air, the DMF in water samplers stayed unchanged for at least for 12 h. The DMF in carbon cloth samplers showed a decay with a half-time of 14.3 h. When the carbon cloth was taken out immediately after termination of DMF exposure, wrapped in aluminum foil, and kept refrigerated, however, there was no measurable decrease in DMF for at least 3 weeks. When the air was drawn at 0.2 l/min, a breakthrough of the silica gel tube took place at about 4,000 ppm.min (as the lower 95% confidence limit), whereas charcoal tubes could tolerate even heavier exposures, suggesting that both tubes are fit to measure the 8-h time-weighted average of DMF at 10 ppm.

Air Pollutants, Occupational↗
PubMed1992

Occupational dimethylformamide exposure. 2. Monomethylformamide excretion in urine after occupational dimethylformamide exposure.

The relationship between the 8-h time-weighted average (TWA) intensity of exposure to N,N-dimethylformamide (DMF) vapor (with little possibility of skin contact with liquid DMF) and the subsequent excretion of N-monomethylformamide (MMF) precursor in shift-end urine samples was examined in 116 workers exposed to DMF and 92 workers exposed to DMF in combination with toluene. Urinary MMF level was examined also in 42 non-exposed subjects. The TWA vapor concentration in breathing zone air of each worker was successfully measured by means of a recently developed diffusive sampler in which water was used as an absorbent. The examination of gas chromatographic (GC) conditions for MMF determination showed that the formation of MMF was not saturated when the injection port temperature was set at 200 degrees C, reached a plateau at 250 degrees C, and showed no additional increase at 300 degrees C. There was a linear relationship between DMF in air and MMF in urine with a regression equation of y = 1.65 x + 1.69 (r = 0.723, P less than 0.01), where y is MMF (unit; mg/l, uncorrected for urine density) in urine and x is DMF (ppm) in air, when only those exposed to DMF were selected, and the injection port temperature was set at 250 degrees C. From this equation, it was possible to estimate that about 10% of the DMF absorbed will be excreted into urine as the MMF precursor. The slope of the regression line was significantly smaller among those exposed to DMF and toluene in combination as compared with those with DMF exposure only.

Adult↗
PubMed1992

Occupational dimethylformamide exposure. 3. Health effects of dimethylformamide after occupational exposure at low concentrations.

A factory survey was conducted in a plant where N,N-dimethylformamide (DMF) was in use during the production of polyurethane plastics and related materials. In all, 318 DMF-exposed workers (195 men and 123 women) and 143 non-exposed controls (67 men and 76 women) were examined for time-weighted average exposure (to DMF and other solvents by diffusive sampling), hematology, serum biochemistry, subjective symptoms, and clinical signs. Most of the exposed workers were exposed only to DMF, whereas others were exposed to a combination of DMF and toluene. DMF exposure in the former group was up to 7.0 ppm (geometric mean on a workshop basis), whereas it was up to 2.1 ppm in combination with 4.2 ppm toluene. Both hematology and serum biochemistry, results (including aspartate and alanine aminotransferases, gamma-glutamyl transpeptidase and amylase) were essentially comparable among the 3 groups. There was, however, a dose-dependent increase in subjective symptoms, especially during work, and in digestive system-related symptoms such as nausea and abdominal pain in the past 3-month period. The prevalence rate of alcohol intolerance complaints among male (assumedly) social drinkers was also elevated in relation to DMF dose.

Adolescent↗
PubMed1992

Detection of late potentials. Comparison of two commercial high-resolution ECG systems.

Signal-averaged electrocardiogram (SAECG) is used for detection of ventricular late potentials (LPs) in cardiac patients. As many commercial SAECG systems become available, it is essential to determine if they provide equivalent diagnostic information. Two high-resolution (Hi-Res) ECG systems (MAC-12, Marquette Electronics, Inc (MEI), Milwaukee, WI and LVP101, Arrhythmia Research Technology (ART), Austin, TX) were tested on 143 subjects (13 controls and 130 cardiac patients, 21 of whom were tested for inducible ventricular tachycardia [VT]). Late potential measurements (total QRS duration, high-frequency low-amplitude signal duration, and root-mean-square voltage) obtained from the two systems were in good agreement in most of the controls and patients. Application of Multicenter criteria for the MEI system and Gomes criteria for the ART system yielded very good agreement in LP diagnosis (at least 2 parameters abnormal). The two Hi-Res systems predicted inducible VT with good accuracy. The MEI system gave slightly higher sensitivity (90% vs 70%) and specificity (91% vs 82%) than the ART system in patients tested for inducible VT. In controls, both systems gave the same specificity (92%) and the LP diagnosis agreed in all controls (100%). Although the number of patients was small, neither sensitivity nor specificity were significantly different between the two systems at p < 0.05. To conclude, MEI and ART Hi-Res systems gave very similar LP diagnoses when appropriate criteria were applied.

Cardiac Pacing, Artificial↗