Search PubMed⌕ Search

Biomedical subjects

H Iguchi

Publications and source records attributed to H Iguchi.

At least 127 records · Page 7Linked to original sources
PubMed1993

EEG changes during mental calculation, reverse recitation and association exercises in patients with dementia of the Alzheimer type.

The cerebral functional impairment in dementia of the Alzheimer type (DAT) was a quantitatively assessed using easily repeatable electroencephalographic analysis. Waveform recognition was employed to analyze the EEG (electroencephalogram) changes displayed before and after tasks of mental calculation, reverse recitation and mental association. Marked decrements in the incidence of theta and alpha waves together with decrements of the average amplitude of alpha waves were noted in normal elderly subjects after mental calculation and reverse recitation. In the patients with DAT, mental association tasks evoked pronounced decrements in the average amplitude of theta waves, the average frequency of alpha waves, and both the average frequency and average amplitude of beta waves. These results indicate that analysis of EEG activity responses to mental tasks provides an objective assessment of dementia.

Aged↗
PubMed1993

Transport of Na+ and HCO3- out of red blood cells is simultaneous with a chloride shift in canine and human whole blood exposed to CO2-rich gas.

To study the release of Na+ from erythrocytes, arterial whole blood obtained from anesthetized and heparinized dogs (n = 8), or human (n = 9) venous blood was aerated with a CO2-rich gas mixture (15% CO2, 25% O2, 60% N2) at a rate of 1 l/min. To examine possible mechanisms involved in the release of sodium ions into plasma, CO2-rich gas was also passed through whole blood in the presence of acetazolamide (n = 8), SITS (n = 8), or furosemide (n = 8). The changes in blood gas parameters, plasma protein concentration, hematocrit, and plasma sodium, chloride, and bicarbonate ion concentrations were examined. When CO2-rich gas was passed through treated and untreated canine or human whole blood, PCO2 and plasma sodium and bicarbonate contents per ml of blood increased, while pH and plasma chloride content per ml of whole blood decreased. After 0 to 5 min of CO2-rich gassing, the mean rates of change in plasma ion contents per ml of whole blood per min were related by the following equations: (1) delta MCI- = a (delta MNa+), (2) delta MHCO3- = b(delta MNa+), (3) delta MHCO3- approximately equal to delta MNa+ + delta MCl-, (4) b approximately equal to 1 + a. These results suggest that the release of Na+ and HCO3- from erythrocytes into plasma in canine and human whole blood occurred in a one-to-one ratio simultaneously with, and probably independently of, the well-known chloride shift during a period of 0 to 5 min after the start of CO2-rich gassing.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed1993

[Evaluation of bladder tumor staging by submucosonography].

Submucosonography to stage tumors of the esophagus and stomach is well reported. Here we report our experience with a modified procedure to evaluate the stage of bladder tumor cystoscopically and compare the results of staging by other methods. The evaluation was carried out on accuracy 10 patients (10 bladder tumors). A water soluble contrast medium (CM: lohexol 33 mg/ml) was injected into the submucosa of the bladder cystoscopically. Usually the injected point was one centimeter to the urethral margin of the tumor and up to three points were selected. Within 30 minutes after the injection, the lateral and frontal X-ray pictures were taken. The accuracies of staging by submucosonography were compared with the results of other methods, i.g., ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI). By submucosonography, three categories depending on the diffusion of CM were classified as follows. Type I: (diffuse type) without disturbance of diffusion. Type II: (borderline type) between type I and III. Type III: (defect type) local disturbance of diffusion. Overall accuracies of each were 70.0% (submucosonography), 62.5% (US), 44.4% (CT), 66.7% (MRI) respectively. The accuracies of submucosonography were high in stage Ta, above stage T2 and low in stage T1.

Adult↗
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

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

Curvi-linear relation between acetone in breathing zone air and acetone in urine among workers exposed to acetone vapor.

An occupational health study was conducted on 45 acetone-exposed male workers in combination with 343 non-exposed men to examine the quantitative relationship between the intensity of acetone vapor exposure and the concentration of acetone in urine. The time-weighted average acetone concentrations were measured by means of diffusive samplers with water as absorbent, whereas urine samples were collected at the end of the shift as well as before the shift on the next morning. Acetone concentration in shift-end urine did not increase when the workers were exposed to acetone up to approx. 15 ppm, and this was followed by a gradual increase at a higher atmospheric acetone concentration, in a manner dependent to acetone vapor concentration. The comparison in acetone concentrations between the urine samples collected at the shift-end and those before the shift of the next morning showed that the levels in two sets of samples were the same among those exposed to 15 or less ppm acetone, whereas acetone in the shift-end samples was significantly higher than the counterpart levels in the pre-shift samples among those exposed to acetone at more than 15 ppm.

Acetone↗
PubMed1992

Production of chromogranin A and B derived peptides in human small cell lung carcinoma cell lines.

Production of chromogranin (Cg)A and B derived peptides [pancreastatin (PST), GAWK, CCB] was studied using human lung carcinoma derived cell lines. PST-like immunoreactivity (LI) was detected in the culture medium in 3 of 6 small cell lung carcinoma (SCLC) cell lines, while GAWK- and CCB-LIs were detected in 5 of 6 and all the 6 SCLC cell lines, respectively. CCB-LI was produced in large amounts in SCLC cell lines as compared to PST- and GAWK-LIs. In non-SCLC cell lines, on the other hand, PST- and GAWK-LIs were not detected. CCB-LI was detected in 1 of 7 non-SCLC cell lines, but not detected in the remainder. PST, GAWK and CCB-LIs, secreted by these cell lines, consisted of several peaks, and these peaks were different among cell lines. This suggests that processing of CgA and B is different in the cell lines. Production of CgA and B derived peptides seems to be a characteristic feature of SCLC, and among them, CCB LI may be a useful marker for SCLC.

Carcinoma, Small Cell↗
PubMed1992

Effect of LHRH on plasma 7B2 in patients with gonadotropin-producing pituitary adenomas.

Plasma immunoreactive (IR)-7B2 was measured in four patients with gonadotropin-producing pituitary adenomas. The basal level of plasma IR-7B2 was elevated in one of the four patients. Hyperresponse of plasma IR-7B2 to LHRH or LHRH/TRH was noted in two patients tested. 7B2 was positively stained in a paraffin-embedded section of gonadotropin-producing pituitary adenoma obtained at surgery. These findings suggest that 7B2 is produced in gonadotropin-producing pituitary adenomas and secreted into the blood stream under certain conditions. 7B2 may be a useful marker for gonadotropin-producing pituitary adenomas.

Adenoma↗
PubMed1992

A possible mechanism of endothelium-dependent relaxation induced by pirarubicin and carbachol in rat isolated aorta.

The mechanism of endothelium-dependent relaxation induced by pirarubicin, (2''R)-4'-O-tetrahydropyranyladriamycin, THP, or carbachol was investigated in the rat isolated aorta. The relaxant effect of THP (1.5 x 10(-6)-4.5 x 10(-5) M) or carbachol (10(-8)-10(-4) M) on the aorta with endothelium was decreased by lowering Ca2+ in the medium. The relaxation induced by THP was not inhibited by pretreatment with verapamil (10(-6)-10(-5) M), and that induced by carbachol was only partially inhibited. However, on replacement of all but 20 mM Na+ with either Li+ or choline, the THP- or carbachol-induced relaxation was inhibited. Furthermore, the relaxing effect of THP or carbachol was inhibited by pretreatment with amiloride (10(-4)-3 x 10(-4) M), with ouabain (10(-4)-10(-3) M), or with K(+)-depletion. These results suggest that the THP- or carbachol-induced relaxation depending on endothelium was affected by modifying the calcium ion concentration, and that a Na(+)-Ca2+ exchange process is involved.

Amiloride↗
PubMed1992

The effects of phentolamine and nitroglycerin on right-sided hemodynamics in cardiac patients can be explained by a shift of the systemic venous return curve and right-ventricular output curve.

The present study investigated the effects of phentolamine (PH) and nitroglycerin (NG) on the hemodynamics of the right heart in patients with cardiac disease. The patients were divided into a well-functioning left heart group (W group, n = 15) and a poorly-functioning left heart group (P group, n = 15). Right cardiac hemodynamic parameters and plasma noradrenaline (NA) and adrenaline (A) concentrations were measured before and after administering PH (0.1 mg/kg, i.v.) or NG (0.6 mg, sublingual). In a parallel animal study we obtained a systemic venous return curve by measuring mean circulatory pressure (MCP), mean right atrial pressure (RAP) and cardiac output, before and after administering PH (0.1 mg/kg, i.v.) or NG (12.5 micrograms/kg, i.v.) to anesthetized open-chest dogs (n = 14). We used MCP data (W group: 7.5 mmHg, P group: 10 mmHg) obtained in a separate series of human studies in our laboratory. We constructed the venous return curve by connecting the MCP point on abscissa with the cardiac index (CI)-RAP plot obtained in the clinical study. We also constructed the right ventricular output curve by connecting the point of -2 mmHg on the abscissa with the CI-RAP plot. We obtained the following results: (1) PH shifted the CI-RAP plot to the left and upwards, while NG shifted the CI-RAP plot to the left almost horizontally on the CI-RAP plane, where CI was plotted on ordinate and RAP on abscissa. The length [formula: see text] C = control point, PH = point after PH) of the shift of CI-RAP plot due to PH was greater in the P group than in W group, while there was no difference in the length [formula: see text] C = control point, NG = point after NG) of the shift of CI-RAP plot due to NG between P and W groups. (2) Both PH and NG significantly elevated plasma NA and A concentrations in both the W and P groups. In the P group, PH increased the plasma NA concentration significantly more than did NG, but both drugs increased plasma A concentration to a similar extent. (3) Both PH and NG significantly decreased the mean pulmonary arterial pressure with NG doing so significantly more than PH.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenergic alpha-Antagonists↗
PubMed1992

Antibody responses of swine to type A influenza viruses in the most recent several years.

A serological survey was conducted on 4,080 swine sera collected for the years 1985-90. The swine sera positive to A/New Jersey/8/76 (swine type H1N1) strain were observed in annual (10-20%) and monthly (20-40%) incidences during the observation period except for occasional months. Antibodies to recent human H1N1 viruses in swine were recognized in relation to the human H1N1 influenza epidemics. Antibody responses of swine to human H3N2 strains appeared irrespective of human epidemics with the virus in the years 1985-87. However, in 1988 almost no antibodies to three human H3N2 isolates of 1983-88 were observed for this year except a few months though the human epidemic occurred in the area. Although in 1989-90 many swine had antibodies to the three strains in the percentage of 3 to 35, no antibody to the latest isolate, A/Hokkaido/20/89 (H3N2), was found for almost all the months of both years. These findings differed markedly from the possible relationship between the prevalence of H3N2 virus-antibodies in swine and the human influenza epidemics, which were described previously in many reports including our studies.

Animals↗
PubMed1991

Evidence for secretion of 7B2 by A- and B-cells of hamster pancreatic islets.

7B2 is a neuroendocrine protein, and in the pancreatic islets the presence of 7B2 in A- and B-cells was immunohistochemically demonstrated. In order to examine 7B2 secretion by A- and B-cells of pancreatic islets, we prepared isolated hamster pancreatic islet cells as well as an A-cell-rich culture, and studied 7B2 secretion under certain stimulations. 7B2 was secreted by isolated hamster pancreatic islet cells. This secretion was stimulated by theophylline and arginine, but glucose had a weak effect on the 7B2 secretion. Such a response of 7B2 to the stimulations was different from that of insulin or glucagon. 7B2 secretion was also noted in the A-cell-rich culture. These results suggest that 7B2 is secreted by both A- and B-cells of the hamster pancreatic islets and its secretion is regulated under certain conditions.

Animals↗
PubMed1991

Early decreases in pulmonary, hepatic and renal glutathione levels in response to cadmium instillation into rat trachea.

After instillation of cadmium (Cd) into the rat trachea, reduced and oxidized glutathione (GSH and GSSG) levels in the lung, liver and kidney were studied in relation to Cd concentrations and metallothionein (Mt) contents. Rats instilled with Cd developed haemorrhagic pneumonia, which deteriorated with a marked swelling of the lung throughout the experimental period of 48 h. The total glutathione (GSH + GSSG) level in the organs decreased after 6 h to 60-70% of the control levels. The decreased glutathione level was never restored to the control level within 48 h in the lung, and was possibly due to the pneumonia. Completely recovered glutathione was seen in other organs. The GSSG level did not decrease significantly in the lung or liver but lowered significantly after 12 h and 24 h. The GSSG fraction in the amount of total glutathione was 10% or more in the lung and 5% or less in the liver or kidney. This finding indicated that the total glutathione level was mainly changed by the decrease in the GSH fraction. Cadmium in the lung increased to 7.3 ppm 3 h after Cd instillation and decreased to 2.5 ppm within 48 h. Cadmium in the liver and kidney gradually increased with time, and after 48 h reached 1.1 and 2.3 ppm, respectively. This indicated a transportation of Cd from the lung to these organs. Moreover, the early stage of Cd accumulation coincided with the total glutathione decrease in the organs. After Cd instillation, pulmonary, hepatic and renal Mt started to increase at 3 or 6 h, and markedly increased at 24 h or later.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

2-Acetylfuran, a confounder in urinalysis for 2,5-hexanedione as an n-hexane exposure indicator.

The apparent amount of 2,5-hexanedione, a biomarker of n-hexane expsoure in occupational health, in the urine of both exposed and non-exposed subjects varied not only as a function of the pH at which the urine sample was hydrolyzed but also depending on the capillary column used for gas chromatographic (GC) analysis of the urinary hydrolyzates after extraction with dichloromethane. The formation of a compound, identified by gas chromatography-mass spectrometry (GC-MS) as 2-acetylfuran, following acid hydrolysis was a major cause of confounding effects. This compound was hardly separated from 2.5-hexanedione on a capillary column such as DB-WAX, whereas separation could be achieved on a DB-1 capillary column. 2-Acetylfuran was formed when a urine sample was heated at a pH of less than 2 for hydrolysis, and the amount detected in urine did not differ between exposed and non-exposed subjects, indicating that the formation of 2-acetylfuran is independent of n-hexane exposure. When urinary hydrolysis is used, hydrolysis at a pH of less than 0.5, extraction with dichloromethane, and GC analysis on a non-polar capillary column are proposed to be the best analytical conditions for 2,5-hexanedione analysis in biological monitoring of exposure to n-hexane.

Confounding Factors, Epidemiologic↗