We examined the hemodynamic effects of 1, 1, 1-trichioroethane (TCE) inhalation in anesthetized dogs in acute inhalation experiments. Six adult mongrel dogs with spontaneous respiration were intubated, connected to a one-way valve. TCE was delivered by the tubular system connected to a 30-liter tedlar bag reservoir filled with 1v/v% of TCE. After TCE inhalation, the animals revealed a significant decrease in systemic arterial pressure following a decrease in systemic vascular resistance. Pulmonary arterial pressure, pulmonary vascular resistance and right cardiac work increased significantly. These changes were compatible with clinical manifestations of TCE intoxication in human beings. In conclusion, inhalation of TCE may not only decrease peripheral vascular resistance, but also induce transient disturbance of pulmonary blood flow with subsequent pressure overloading in the right ventricle.
Occupational exposure to mercury has long been associated with renal proximal injury and an increased incidence of proteinuria, as has such exposure to cadmium. Renal citrate excretion is very important with respect to acid-base balance since the metabolism of citrate generates three bicarbonate ions. In this study, we exposed isolated rat renal brush border membrane vesicles (BBMV) to mercury (Hg2+) and examined their citrate uptake characteristics. BBMV were prepared by the divalent cation precipitation method. Citrate uptake was measured by the Millipore rapid membrane filtration method. The preincubation of BBMV with 0.5 and 2mM HgCl2 for 1min significantly inhibited citrate uptake compared with that of BBMV without Hg preincubation. The analysis of the time course of citrate uptake during a 30-min preincubation of BBMV with 0.1mM Hg2+ also revealed a significant reduction in the uptake compared with that of the control BBMV without preincubation. These findings indicate that the preincubation of BBMV with mercury results in a time- and concentration-dependent inhibition of citrate uptake.
Dogs were exposed to 1% (v/v) (10, 000ppm) vapor of 1, 1, 1-Trichloroethane (1, 1, 1-TCE) by inhalation for 3 min repeated four times at 4hr intervals under continuous anesthesia. Changes in the 1, 1, 1-TCE concentration in blood with time, as well as distribution of 1, 1, 1-TCE in the organs and tissues (lungs, liver, kidneys, heart, brain, and fat around the kidneys and on the abdominal wall) upon completion of the four exposures were studied. Concentrations of 1, 1, 1-TCE in blood showed the highest level immediately after exposure, and fairly decreased in about 30 min after exposure. The half life of 1, 1, 1-TCE in blood was 4-12 min after exposure. Upon completion of the exposures (3 min inhalations repeated four times), 1, 1, 1-TCE concentrations per gram wet weight of each organ ranged from 0.1 to 0.5μg/g in the lungs, liver, kidneys, heart and brain. On the other hand, the 1, 1, 1-TCE concentration in fat ranged from 16.9 to 54.6μg/g, greatly exceeding those in other organs.
With objective to find out prevalence of Coal Worker's Pneumoconiosis and variation among readers in reading x-ray plates for pneumoconiosis, a retrospective epidemiological survey of Coal Worker's Pneumoconiosis was undertaken in 72 collieries of Madhya Pradesh and Orissa by re-reading of x-ray plates taken during the Periodical Medical Examination at the Occupational Health Units over a period of 5 years. Six readers, trained abroad in reading pneumoconiosis x-ray plates, were involved for the study. Each reader reported approximately one sixth of the available x-ray plates of all the collieries and classified on the 12 point scale of I.L.O. (International Labour Organisation) 1980 in special format. Total 43, 504 chest x-rays were reviewed. The overall prevalence was found to be 3.03%, ranging from 1.52% to 4.76% between 10 areas (group of mines). Major category of profusion was category-I (81.09%), followed by category-II (17.84%). Only 3 cases of Progressive Massive Fibrosis (PMF) were detected. Round shaped opacities are predominant (89.59%) in Coal Worker's Pneumoconiosis. Among the opacities, ‘p’ type is more prevalent (48.29%) followed by ‘q’ type (40.62%). There was variation amongst the different readers and ranged from 1.14% to 6.76% for reporting the prevalence of Coal Worker's Pneumoconiosis. However, when analysis of six readers for inter reader variation was conducted, that shows no abnormal deviation in the reading of any of the readers.
A simple sampling and analytical method for monitoring carbon disulfide (CS2) vapor was investigated to assess exposure to low levels of CS2 in a viscose rayon factory. CS2 vapor was adsorbed on polymer beads (poly (2, 6-diphenyl-p-phenylene oxide)) packed in a diffusive sampling tube. The sampling tube was heated at 180°C for 7 min using a Daily Exposure Limit Test Apparatus, and thermally desorbed CS2 was measured by a stain tube for CS2. In laboratory experiments, the indicated CS2 levels measured by this method were highly correlated with calibrated CS2 concentrations (1-40ppm), exposure duration (1-8hr) and cumulative exposure levels. The CS2 values were stable up to 7 days after sampling when the diffusive tubes were stored at 4°C and 20°C. The effects of relative humidity, wind velocity and hydrogen sulfide on the measured values were negligible. In a field survey, 65 workers in a viscose rayon factory wore both the diffusive sampling tube and a commercially available 3M 3500 organic vapor monitor on their collar during their 8-hr work period. CS2 concentrations obtained by the two methods were comparable and the correlation coefficient was 0.931. This method proved to be useful in determining the concentrations of CS2 to which workers were exposed.
An infrasound experiment system has been constructed in order to investigate the effects of infrasound on human health from the point of view of industrial hygiene and to establish a method to assess it in working environments. Some measurements were carried out to evaluate the acoustic performance of the system in the low frequency sound range, including infrasound, and to clarify the points to be improved. As a result, it was found that the system had some weak points in the audible frequency range. They were considered to be causedBy the large capacity of the test chamber, and some countermeasures were required. On the other hand, in the infrasound range, it appeared that the higher harmonics of infrasound possibly affected the experiments and some limitations might be found necessary. But the frequency response of the chamber and the spatial uniformity of the reproduced infrasound proved to be satisfactory for the experiments in this range. Consequently it was concluded that the system could contribute to the study of infrasound.
Methods were developed for the determination of urinary phenylmercapturic acid (PMA), a metabolite specific for benzene, benzylmercapturic acid (BMA), a metabolite of toluene and phenylhydroxyethylmercapturic acids (PHEMAs), specific for styrene, in human beings. Methods involved sample clean up followed by deacetylation and derivatization of the compounds with o-phthaldialdehyde and 2-mercaptoethanol. The fluorescent derivatives were separated on reversed-phase columns with gradient runs and detected by a fluorescence detector. The detection limits were 0.5μg/l for PMA and BMA, and 7μg/l for PHEMAs. The background levels of PMA were higher in smokers than in nonsmokers, while no difference was found in the levels of BMA and PHEMAs. Coexposure to ethanol enanched the excretion of BMA in subjects experimentally exposed to toluene. Correlations were found between environmental benzene (r=0.74, log transformed data), toluene (r=0.74) or styrene (r=0.56) and specific mercapturic acids in workers. The usefulness of PMA, BMA and PHEMAs as biomarkers is critically evaluated.
A comparative study of challenge aerosols was conducted to review a performance test for dust respirators. The national approval test for dust respirator certification in Japan requires that air containing quartz particles of smaller than 2μm in diameter should be used as the test aerosol. Aerosols with broad size distributions may therefore be used as the test aerosols. In view of the international harmonization of respirator certification standards, it is necessary to use alternative test aerosols for the approval test for dust respirators. The present study was undertaken to measure the collection efficiency of filters by using three kinds of test aerosols, i.e., quartz dust, sodium chloride and dioctyl sebacate mist aerosols. We used the cartridges of dust respirators and filtering facepieces from eight Japanese and foreign manufacturers, all of which have been certified by the national approval test. Good correlation among themeasured collection efficiencies was found for the three test aerosols, but penetrations with sodium chloride and dioctyl sebacate mist aerosols were more than 10 times those of quartz dust aerosol.
Phthalic anhydride (PA), used in the chemical industry, binds to proteins and causes allergic reactions. It is important to study the characteristics of antibody to PA-protein. We produced specific IgG against PA-rabbit serum albumin (RSA) by administering subcutaneous injections of PA-RSA conjugate to two rabbits. Both rabbits' sera had high titers of IgG not only to PA-RSA but also to PA-human serum albumin (HSA) and HSA. In enzyme-linked immunosorbent assay (ELISA) and ELISA HSA inhibition, specific IgG to PA-HSA revealed cross-reactivity to three other phthalyl anhydride conjugates, hexahydrophthalic anhydride (HHPA)-HSA, methylhexahydrophthalic anhydride (MHHPA)-HSA, and methyltetrahydrophthalic anhydride (MTHPA)-HSA, in both sera. Titers of IgG to HHPA-HSA, MHHPA-HSA, and MTHPA-HSA were not significantly different. On affinity chromatography, highly specific IgG to PA hapten alone was purified. In the serum not binding to PA column, specific IgG to PA-HSA was significantly less than in original serum, but levels of specific IgG to other phthalyl anhydride-HSA were unchanged. Rabbits immunized with PA-RSA produced at least two types of IgG: one is to PA hapten alone and the other may be against new antigenic determinants (NADs) on HSA.
To elucidate the action of nitroglycol (Ng) on cardiac muscles, the contractile and chronotropic responses of the isolated rat cardiac muscles to Ng in a cumulative manner were investigated. Ng produced negative chronotropic and inotropic effects on spontaneously beating right atria in concentrations ranging from 10-7 to 3×10-4M. Ng also produced dose-dependent negative inotropic effects on electrically driven left atrial muscles. On the other hand, in right ventricle muscles, Ng induced positive inotropic effects. These results suggest that Ng acts directly on the cardiac muscles as well as vascular smooth muscles in acute poisoning.
Effects of single intraperitoneal (i.p.) administration of carbon tetrachloride (CC4), chloroform (CHCl3), and dichloromethane (CH2Cl2) on lipoproteins in plasma and liver were investigated in rats. Changes in lipoproteins caused by these solvents were compared with changes in traditional hepatotoxicity markers such as GPT (ALT). Following the administration, concentrations of lipoproteins (VLDL, LDL, HDL), triglyceride, cholesterol, and GPT activity in plasma were determined through changes in liver weight, liver content of triglyceride, malon dialdehyde (MDA), and glutathione (GSH). Time-course study revealed that changes in plasma and liver reached their peaks at 19 or 32hr following the administration of CCl4 or CHCl3. Peaks of changes were observed at 8 or 19hr following the administration of CH2Cl2. Dose dependency of these changes was investigated at dosages of 3, 30, and 300mg/kg of CCl4 or CHCl3, and 300, and 1, 000mg/kg of CH2Cl2. Significant decreases in triglyceride and apolipoproteins in VLDL fraction were observed at 3mg/kg of CCl4. Such VLDL components decreased at 30mg/kg of CHCl3. HDL decreased significantly at 300mg/kg of CH2Cl2 and marked increase in LDL occurred at 1, 000mg/kg of the solvent. Liver weight and liver content of triglyceride and MDA significantly increased at 30mg/kg of CCl4, while significant increase in GPT activity was observed at 300mg/kg of CCl4 and CHCl3. GPT increased significantly at 1, 000mg/kg of CH2Cl2. These results revealed that changes in plasma lipoproteins can serve as sensitive and simple markers for liver disorders caused by chlorinated hydrocarbon solvents such as CCl4, CHCl3, or CH2Cl2.
We investigated the parasympathetic nervous response to psychological test using heart rate variation (HRV) during deep breathing in elderly patients with hand-arm vibration syndrome and healthy controls. Average age (SD) of 16 patients with vibration-induced white finger (VWF), 13 patients without VWF and 12 healthy controls was 60.1 (2.8), 60.6 (4.2) and 58.8 (3.8), respectively. After an initial supine rest for 40min, psychological test (Stroop color word test and mirror drawing test) was performed for 20min. The indexes ofHRV (Mean R-R, SD, RMSSD and CV) were calculated. Blood pressure and heart rate were also measured. The indexes ofHRV did not differ between the groups before exposure. The SD, RMSSD and CV of the patients without VWF during supine deep breathing after 3min post-exposure supine rest were significantly lower than those of the control group (p<0.05). The Mean R-R of the patients without VWF significantly increased (p<0.05). Blood pressure did not differ in either before or after exposure measurements. The results suggest that the post-exposure response of the parasympathetic nervous system to psychological test reduced in the patients without VWF.
The workers were classified into two groups according to their median value of blood and urine lead levels and urine ALA levels. The group of workers whose blood lead levels were in a lower range (1-15μg/dl) exhibited significantly lower hematocrit, hemoglobin and erythrocytes than the group of the workers whose blood lead levels were in a higher range (16-39μg/dl) (P<0.001). However, there were no significant differences in the mean values of hematocrit, hemoglobin and erythrocyte counts between the workers whose urine lead or ALA levels were below the median value and those whose urine lead or ALA levels were above the median value. Because the bulk of blood lead is reported to exist in the soluble fraction of erythrocytes, low levels of blood lead are believed to exhibit low levels of anemia indicators.
A single intraperitoneal injection of lead acetate (200mg/kg body weight) increased the lipid peroxidation potential (LPP) measured as thiobarbituric acid-reactive substance (TBA-RS) in different tissues of Swiss mice. All the tissues taken for experimentation, generated significantly higher amount of TBA-RS in lead-treated mice when compared with the respective control value. However, none of the tissues could correspond to the control value after the lapse of four weeks post-treatment. Possibilities of differential responsiveness of tissues to generate lipid peroxides in lead-treated mice have been discussed.