Presence of specific IgG antibody to grain dust does not go with respiratory symptoms.
A high prevalence of work-related symptoms in relation to grain dust exposure has been reported in grain dust workers, but the role of the specific IgG antibody is unknown. To study the possible role of specific IgG (sIgG) and specific IgG4 (sIgG4) in the development of work-related symptoms, sIgG and sIgG4 subclass antibodies against grain dust antigens were determined by ELISA in sera from 43 workers and 27 non-exposed controls. They were compared with results of specific IgE antibodies, exposure intensity and the presence of respiratory symptoms. SIgG and sIgG4 antibodies were detectable in almost all sera of exposed workers, and the prevalence were significantly higher than those of controls (p<0.05). Higher sIgG4 was noted in workers with specific IgE (p<0.05). The correlation between sIgG and exposure duration was significant (p<0.05). There was no association between the prevalence of sIgG and sIgG4 and the presence of respiratory symptoms, or work stations. In conclusion, these results suggest that the existence of sIgG and sIgG4 might represent a response to grain dust exposure and may unlikely play a role in the etiology of respiratory symptoms. (+info)
Exposure of farmers to phosmet, a swine insecticide.
OBJECTIVES: The goal of this study was to measure dermal and inhalation exposures to phosmet during application to animals and to identify what determinants of exposure influence the exposure levels. METHODS: Ten farmers were monitored using dermal patches, gloves, and air sampling media during normal activities of applying phosmet to pigs for insect control. Exposures were measured on the clothing (outer), under the clothing (inner), on the hands, and in the air. Possible exposure determinants were identified, and a questionnaire on work practices was administered. RESULTS: The geometric mean of the outer exposure measurements was 79 microg/h, whereas the geometric mean of the inner exposure measurements was 6 microg/h. The geometric mean for hand exposure was 534 microg/h, and the mean air concentration was 0.2 microg/m3. Glove use was associated with the hand and total dermal exposure levels, but no other determinant was associated with any of the exposure measures. The average penetration through the clothing was 54%, which dropped to 8% when the farmers wearing short sleeves were excluded. The farmers reported an average of 40 hours a year performing insecticide-related tasks. CONCLUSIONS: Farmers who applied phosmet to animals had measurable exposures, but the levels were lower than what has been seen in other pesticide applications. Inhalation exposures were insignificant when compared with dermal exposures, which came primarily from the hands. Clothing, particularly gloves, provided substantial protection from exposures. No other exposure determinant was identified. (+info)
Increase in interleukin-6 and fibrinogen in peripheral blood after swine dust inhalation.
OBJECTIVES: The inhalation of dust from swine confinement buildings causes inflammatory responses in the airways with a rise of interleukin-6 (IL-6). The purpose of this study was to confirm the increase in serum IL-6 after inhalation of swine dust and investigate a possible increase in plasma fibrinogen. METHODS: Eight healthy nonsmoking volunteers inhaled dust for 4 hours inside a swine confinement building. Inhalable dust and endotoxin were sampled. The concentrations of IL-6 and fibrinogen were determined in serum and plasma. RESULTS: The study showed a clear increase in the concentrations of IL-6 and fibrinogen after exposure. CONCLUSIONS: As fibrinogen is an important risk factor for ischemic heart disease, the increased concentration of fibrinogen among persons exposed to swine dust may increase the risk for this disease. (+info)
Butadiene diolepoxide- and diepoxybutane-derived DNA adducts at N7-guanine: a high occurrence of diolepoxide-derived adducts in mouse lung after 1,3-butadiene exposure.
Butadiene (BD) is a high production volume chemical and is known to be tumorigenic in rodents. BD is metabolized to butadiene monoepoxide (BMO), diepoxybutane (DEB) and butadiene diolepoxide (BDE). These epoxides are genotoxic and alkylate DNA both in vitro and in vivo, mainly at the N7 position of guanine. In this study, a 32P-post-labeling/thin-layer chromatography (TLC)/high-pressure liquid chromatography (HPLC) assay for BDE and DEB adducts at the N7 of guanine was developed and was used in determining the enantiomeric composition of the adducts and the organ dose of BD exposure in lung. Exposure of 2'-deoxyguanosine (dGuo), 2'-deoxyguanosine-5'-phosphate (5'-dGMP) and 2'-deoxyguanosine-3'-phosphate (3'-dGMP) to racemic BDE followed by neutral thermal hydrolysis gave two products (products 1 and 2) that were identified by MS and UV and NMR spectroscopy as a diastereomeric pair of N7-(2,3,4-trihydroxybutan-1-yl)-guanines. Exposure of dGuo nucleotides to RR/SS DEB (also referred to as dl DEB) followed by thermal depurination resulted in a single product coeluting with the BDE product 1. If the reaction mixture of BDE and 5'-dGMP was analyzed by HPLC before hydrolysis of the glycosidic bond, four major nucleotide alkylation products (A, B, C and D) with identical UV sepectra were detected. The products were isolated and hydrolyzed, after which A and C coeluted with product 1 and B and D coeluted with the product 2. The major adduct of DEB-exposed 5'-dGMP was N7-(2-hydroxy-3,4-epoxy-1-yl)-dGMP (product E). A 32P-post-labeling assay was used to detect BDE- and DEB-derived N7-dGMP adducts in DNA. Levels of adducts increased with a dose of BDE and DEB and exhibited a half life of 30 +/- 3 (r = 0.98) and 31 +/- 4 h (r = 0.95), respectively. Incubation of DEB-modified DNA at 37 degrees C at neutral pH for up to 142 h did not lead to an increase of N7-(2,3,4-trihydroxybutan-1-yl)-dGMP in the DNA. These observations led to the conclusion that the N7-(2,3, 4-trihydroxybutan-1-yl)-dGMP adducts in DNA can be used as a marker of BDE exposure and that N7-(2-hydroxy-3,4-epoxy-1-yl)-dGMP adducts are related to DEB exposure. Dose-related levels of BDE- and DEB-derived adducts were detected in lungs of mice inhaling butadiene. Most of the N7-dGMP adducts (73%; product D) were derived from the 2R-diol-3S-epoxide of 1,3-butadiene. The data presented in this paper indicate that in vivo, 98% of N7-dGMP alkylation after BD exposure is derived from BDE, and approximately 2% of the adducts were derived from DEB and BMO. (+info)
Should we be frightened of bracken? A review of the evidence.
OBJECTIVE: To assess the risk to human health of the plant bracken (Pteridium sp). DESIGN: An evaluation of studies of human and animal populations exposed to bracken, together with a review of expert reports and advice to the public. MAIN RESULTS: Bracken induced disease has been demonstrated in animals in both laboratory and field studies. Depending on the species, diseases in animals associated with the plant have included; cancers of the alimentary and urogenital tract, lung and breast; haematuria; retinal degeneration; and, thiamine deficiency. Potential exposure of human populations is through: food either directly (people in some parts of the world eat bracken as a traditional dish) or indirectly by consuming animals fed on bracken; milk; water; inhalation and ingestion of spores; and insect vectors. Four studies of human populations (two analytical and two observational) failed to assess adequately confounding factors and other sources of bias, so that conclusions about a risk to human health from bracken cannot firmly be drawn. Establishing exposure is also extremely difficult in populations (such as the United Kingdom) where direct consumption of bracken is rare. CONCLUSION: Bracken is a common plant worldwide. It is toxic to many animal species and to several organ systems. There is no tumour (or other disease) that is pathognomic of exposure in animals, though cancers of the alimentary and urogenital tract seem to be the most commonly associated. It is not possible to extrapolate from animal models to humans. Studies of human populations, do not establish a clear risk of bracken to human health, largely because of methodological problems. Testing the evidence against traditional criteria of causality only fulfils the criterion of biological plausibility. Despite this, current public information implies a serious risk to human health from bracken, and increasing media coverage of the subject is likely to lead to greater public concern. Further epidemiological studies are required. (+info)
Determinants of exposure to inhalable particulate, wood dust, resin acids, and monoterpenes in a lumber mill environment.
In a lumber mill in the northern inland region of British Columbia, Canada, we measured inhalable particulate, resin acid, and monoterpene exposures, and estimated wood dust exposures. Potential determinants of exposure were documented concurrently, including weather conditions, tree species, wood conditions, jobs, tasks, equipment used, and certain control measures. Over 220 personal samples were taken for each contaminant. Geometric mean concentrations were 0.98 mg/m3 for inhalable particulate, 0.49 mg/m3 for estimated wood dust, 8.04 micrograms/m3 for total resin acids, and 1.11 mg/m3 for total monoterpenes. Multiple regression models for all contaminants indicated that spruce and pine produced higher exposures than alpine fir or mixed tree species, cleaning up sawdust increased exposures, and personnel enclosure was an effective means of reducing exposures. Sawing wood in the primary breakdown areas of the mill was the main contributor to monoterpene exposures, so exposures were highest for the barker operator, the head rig operator, the canter operator, the board edgers, and a roving utility worker in the sawmill, and lowest in the planer mills (after kiln drying of the lumber) and yard. Cleaning up sawdust, planing kiln-dried lumber, and driving mobile equipment in the yard substantially increased exposures to both inhalable particulate and estimated wood dust. Jobs at the front end of the sawmill where primary breakdown of the logs takes place had lower exposures. Resin acid exposures followed a similar pattern, except that yard driving jobs did not increase exposures. (+info)
Occupational exposure to dust in quartz manufacturing industry.
Owing to the abundance of a sedimentary rock, 65 small-scale quartz manufacturing enterprises, employing 650 workers, have been established in the region studied. Quartz powder manufacturing involves various processes and operations, such as manual handling of quartz stones, crushing, grinding, sieving, screening, mixing, storing and bagging. Results demonstrate that each of these operations generates high concentrations of airborne 'total' dust and respirable dust, which contain a very high percentage (> 75%) free silica. The estimated average exposure to airborne 'total' dust was 22.5 mg m-3 (Permissible Limit of Exposure 1.08 mg m-3), and respirable dust 2.93 mg m-3 (PLE 0.36 mg m-3). This shows that 'total' dust exposure was 7.7 times higher than respirable dust. Since the present work systems and practices may pose a serious health risk to the workers, public and the environment, suitable preventive and control measures have been suggested for improvement in the workplace. (+info)
Systemic sclerosis (scleroderma) in two iron ore mines.
Six males with systemic sclerosis were observed in the work forces of two iron ore mines. The usual spectrum of clinical features encountered in systemic sclerosis patients were present. Histologic examination of pulmonary tissue was performed on three of the cases and showed features of both silicosis and scleroderma but to different degrees and stages of development. Exposure to high levels of silica-containing dusts had occurred in all six cases. (+info)