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At least 595 records · Page 33Linked to original sources
PubMed1990

The application of dustiness tests to the prediction of worker dust exposure.

Laboratory bench tests, known as dustiness tests, have been used to evaluate and compare the potential of various powders to cause occupational dust exposure. Dustiness tests are used to develop products with reduced dust emissions. The correlation between dustiness test results and dust exposures was evaluated at two bag dumping and bag filling operations. At one bag dumping and one bag filling operation, there was evidence of a relationship between dustiness test results and dust exposures. In one case, regression analysis showed that dust exposures could be predicted to within nearly one order of magnitude. The variability in this prediction was caused by the inherent variability in the occupational dust exposures. In the other case, there was evidence of a correlation after the data had been adjusted for the effect of varying drop height. At the remaining two operations, no correlation between dust exposures and dustiness test results were observed. These results indicate that the relevance of dustiness tests to occupational dust exposure needs to be evaluated at each site. Because a better option does not exist, manufacturers should continue to use empirical dustiness tests to develop better products in the laboratory. The conclusions reached in the laboratory need to be validated by dust exposure measurements in the field, however.

Air Pollutants, Occupational↗
PubMed1991

Development of impactor size-selective dust samplers at the Elliot Lake Laboratory.

The Elliot Lake Laboratory designs and uses impactor size selectors for respirable and other dust samplers both in the laboratory and in mines. Advantages of the selectors are compact size, reproducibility of size-selection performance based on the high precision of drill manufacture and use, flexibility in design and layout, and manufacturing ease in a machine shop. The major problems in design and performance were secondary deposition of dust and overloading with coarse dust. Secondary deposition modified the calculated size selection and either limited the spacing between adjacent orifices or orifices and other features or required a final calibration. Overloading of the coarse dust deposition zone led to changes in size-selection characteristics as the dust load increased, giving a definite limit to acceptable dust collection quantities. The use of multiple stages increased the coarse dust-holding capability manyfold. All the dust samplers developed at the Elliot Lake Laboratory used two or more successive stages to increase dust-holding capacity.

Dust↗
PubMedDate not supplied

Dynamic monitoring of the dust pickup efficiency of vacuum cleaners.

This study evaluated a new method that uses an optical aerosol photometer for dynamically monitoring dust pickup efficiency during vacuuming. In the first stage of this study the new method was compared with built-in dirt sensors installed by vacuum cleaner manufacturers. Through parallel testing it has been shown that the widely available built-in dirt sensors are not sensitive enough to register small (< 53 microm) dust particles. Therefore, only the optical photometer was used in the rest of the experiments of this study to monitor the dust pickup efficiency while the vacuum cleaner was operated with different nozzles on clean and soiled carpet and vinyl sheet flooring. This method also was used to monitor dust pickup efficiency when vacuuming carpets originating from lead-contaminated homes. The dust pickup efficiencies obtained with the optical aerosol photometer have been compared with the surface lead concentrations found during different stages of cleaning. Results indicate that the dust mass concentration registered with the optical aerosol photometer at the nozzle outlet correlates well with the dust mass collected in the vacuum cleaner filter bag and with the surface lead level. Therefore, dynamic dust pickup monitoring can provide valuable information about the efficiency of cleaning when a vacuum cleaner is used. This suggests that a small aerosol photometer similar to a light-scattering smoke detector would be beneficial in vacuum cleaners used for cleaning surfaces contaminated with leaded dust and biological particles (including allergens).

Aerosols↗
PubMedDate not supplied

Comparison of coal mine dust size distributions and calibration standards for crystalline silica analysis.

Since 1982 standard calibration materials recommended for respirable crystalline silica analysis by the Mine Safety and Health Administration (MSHA) P7 Infrared Method and the National Institute for Occupational Safety and Health (NIOSH) X-ray Diffraction (XRD) Analytical Method 7500 have undergone minor changes in size distribution. However, a critical assumption has been made that the crystalline silica in ambient mine atmosphere respirable dust samples has also remained essentially unchanged in particle size distribution. Therefore, this work compared recent particle size distributions of underground coal mine dust and the silica component of these dusts with estimated aerodynamic particle size distributions of calibration standard materials MIN-U-SIL 5, Berkeley 5, and SRM 1878 used by two crystalline silica analysis techniques. Dust impactor sampling data for various locations in 13 underground coal mines were analyzed for the respirable mass median aerodynamic diameters. The data suggest that the MSHA P7 method will underestimate the silica content of the sample by at most 7.4% in the median size range 0.9 to 3.6 microm, and that it is unlikely one would obtain any significant error in the MSHA P7 method analysis when the method uses Berkeley 5, MIN-U-SIL 5, or SRM 1878 as a calibration standard material. The results suggest that the NIOSH Analytical Method 7500 would be more appropriate for a dust sample that is representative of the total (no cyclone classifier) rather than the respirable airborne dust, particularly because the mass fraction in the size range below 4 microm is usually a small percentage of the total airborne dust mass. However, NIOSH Analytical Method 7500 is likely to underestimate the silica content of an airborne respirable dust sample by only 5 to 10%. The results of this study also suggest that any changes that may have occurred in the median respirable size of airborne coal mine dust are not significant enough to cause any appreciable error in the current methods used for respirable crystalline silica analysis.

Coal↗
PubMed1994

The real-time dust exposures of sodium borate workers: examination of exposure variability.

As part of an epidemiologic study of acute respiratory irritation, an assessment of the short term (TWA-0.25 hr) and daily (TWA-6 hr) dust and boron exposures of workers in a sodium borate production facility was undertaken. A real-time continuous aerosol monitor was used in an active mode with an in-line filter to collect a TWA-6 gravimetric sample with a datalogger to store the continuous aerosol measurements. Over 430 person-days of personal exposure measurements were made, resulting in more than 10,000 15-minute average (TWA-0.25) dust concentration measurements. The arithmetic mean total dust concentrations for the 13 job groups exposed to sodium borate dust ranged from 0.29 to 18.95 mg/m3. The geometric standard deviation of the TWA-6 total dust exposures within the sodium borate exposed job groups had a median of 2.78. The geometric standard deviation of the TWA-0.25 total dust exposures had a median of 3.97. In most jobs the "within-day" variability accounted for over 50% of the total variability in exposure levels. In jobs with constant exposure to sodium borate, the second most important source of exposure variability was attributable to "between worker" differences. Where there was only intermittent exposure, the second most important source of exposure variability was "within-worker" variability. The implications of these findings for control strategies are discussed. Based on boron measurements, a substantial portion of a total dust air sample is nonborate material such as cigarette smoke, vehicle exhaust, ambient dust, or hydration mass. Thus, even in an environment where sodium borate is being packaged, total dust measurements are an overestimate of the actual borate exposure level.

Air Pollutants, Occupational↗
PubMed1995

Dust mite allergens in the office environment.

The objective of this study was to evaluate the extent of dust mite infestation and its contribution to the health complaints in office settings. The methodology recommended for residential dwellings was evaluated for use in the work environment. Der p I allergen-specific ELISA was chosen as a primary method. A liquid chromatography method for guanine is suggested as a backup method to cover a few cases where other mite species may be encountered. The levels of dust mite allergens were measured in 14 offices in response to numerous health complaints. Approximately one-half of the offices investigated were identified as having a dust mite population. Four offices showed levels of Der p I in the dust greater than 1 microgram/g. In two offices, the dust mite allergens were the source of the health complaints. In the other two offices, dust mite allergens were one of the contaminants in the office environment. In all cases, the infestation of dust mites in the offices was localized to a few specific work areas. Office chairs were the primary location where dust mites thrived. The remedial measures included regular cleanup of all fabric-covered office furnishings. Steam cleaning was recommended to eliminate dust mite populations.

Air Pollution, Indoor↗
PubMed1998

Organic dust exposures from work in dairy barns.

Environmental surveys were conducted in 85 barns, predominantly dairy, in central Wisconsin to characterize exposures to organic dusts and dust constituents from routine barn work. Environmental analytes included airborne dusts (total, inhalable inlet, and respirable), particle size distributions, endotoxins, total spore and bacteria counts, viable bacteria and fungi, histamine, cow urine antigen, mite antigen, ammonia, carbon dioxide, and hydrogen sulfide. The geometric mean (GM) concentration of airborne dusts include area total, 0.74 mg/m3; personal inhalable inlet, 1.78 mg/m3, and area respirable, 0.07 mg/m3. Viable bacteria and fungi, spores, endotoxins, histamine, cow urine antigen, and mite antigen were quantifiable constituents of these organic dusts and potential respiratory exposure hazards from routine dairy barn work. Endotoxin concentrations from the inhalable inlet samples ranged from 25.4 endotoxin units per cubic meter of air (EU/m3) to 34,800 EU/m3. The GM endotoxin concentration from these samples, 647 EU/m3, exceeds estimated threshold exposure levels for respiratory health effects. Ammonia was a common irritant quantified in most dairy barns. There were significant correlations between the concentrations of organic dusts and certain dust constituents, although in most instances these correlations were not strong. These sampling results demonstrate the complex nature of organic dusts and provide quantitative description of the exposures to toxic and immunogenic dust constituents during routine barn work.

Air Microbiology↗
PubMed2002

In vitro bioavailability of heavy metals in pressure-treated wood dust.

Pressure treatment with chromium, copper, and arsenic (CCA) is the most prevalent method for protecting wood used in outdoor construction projects. Although these metals are tightly bound to the wood fibers and are not released under most conditions of use, we examined the bioavailability of metals in CCA pressure-treated wood dust in vitro. Cytotoxicity and metallothionein (MT) mRNA expression were examined in V79 Chinese hamster lung fibroblast cells incubated with respirable-size wood dust generated by sanding CCA-treated and untreated (control) Southern yellow pine. In colony survival studies, increased cytotoxicity (p < 0.05) occurred in V79 cells treated with CCA wood dust (351 +/- 77 microg/ml, mean +/- SE) compared with control wood dust (883 +/- 91 microg/ml). Increased cytotoxicity with CCA wood dust also occurred in an arsenic resistant subline of V79 cells, thus suggesting that arsenic was not responsible for the increased cytotoxicity. Metallothionein mRNA was significantly increased after 48 h of treatment with CCA wood dust compared with control wood dust. Incubation of CCA wood dust in cell culture media resulted in the transfer of copper, but not chromium or arsenic, into the media. Moreover, the treatment of cells with this filtered extract resulted in significantly increased metallothionein mRNA, suggesting that bioavailable copper is responsible for inducing metallothionein mRNA in V79 cells. Thus, these bioassays suggest that metals become bioavailable during in vitro culture of phagocytic V79 cells with CCA wood dust.

Animals↗
PubMed1993

Exposure to house dust mite allergen of children admitted to hospital with asthma.

Eighty-two children admitted to hospital with exacerbations of asthma were studied to determine how many were exposed to house dust mites at the time of admission and displayed immediate hypersensitivity to house dust mites. The concentration of house dust mite allergen (Der p I) was measured in dust obtained from the child's mattress, bedroom floor and living room floor. Sixty-two (75%) children admitted had been exposed to > 10 microg Der p I/g. Sixty-seven (82%) children were sensitive to house dust mite (RAST > or = 1 +, or weal > or = 3 mm): 49 (60%) children were both exposed and sensitive. In contrast in a control group of 44 children, 31 (70%) (n.s.) were exposed to > 10 microg Der p I/g, 10 (23%) (P<0.001) were sensitive to house dust mite, and 7 (16%) (P<0.001) were both exposed and sensitive. Seventy-three homes were revisited 6 months after the child's initial admission. During the preceding month 14 children had been readmitted, 12 were fully investigated; of these 10 were both sensitive to house dust mite and still exposed to > 10 microg Der p I/g. In contrast, of the remaining 62 children who were not readmitted, only 19 were both sensitive and still exposed to > 10 microg Der p I/g (P<0.001). In conclusion, the majority of children admitted to hospital with exacerbations of asthma were exposed to house dust mite allergen and were house dust mite sensitive. Further the results suggest that continued exposure to higher concentrations of mite allergen may be associated with the risk of readmission.

Adolescent↗
PubMed1991

Dust from carpeted and smooth floors. IV. Solid material, proteins and allergens collected in the different filter stages of vacuum cleaners after ten days of use in schools.

The accumulation of dust, proteins and allergens from alder, birch, timothy, cat, dog, mite, hen egg white, codfish and mould in schools was investigated by analysing the content of vacuum cleaners after 10 days of use. The main goals were to compare the dust accumulation on carpeted and smooth floors and to estimate to what degree the three vacuum cleaner filter stages (i.e. the disposable bag, the main filter and the microfilter) collected dust, proteins and allergens. Carpeted floors accumulated more dust, proteins and allergens per unit area than smooth floors. Histamine release studies of some of the dust extracts showed that the dust from carpeted floors released histamine from passively sensitized basophils at concentrations for which dust from smooth floors gave low or no histamine release. The analyses showed that most of the dust, proteins and allergens were retained in the dust bags. Less than 1% of the vacuumed material had accumulated in the main filters, which, according to the manufacturer, detain 99.5% of particles greater than 2 microns. By the use of a scanning electron microscope (SEM), particle deposits were observed in the microfilters. These deposits, which represented less than 0.1% of the total mass, showed no significant allergenic activity. Thus, for the field conditions of this study, the microfilters were not needed for cleaning the exit air of allergens, although they were useful for removing fine (less than 2 microns) particles.

Air Pollutants↗
PubMed1994

Fungal propagules in house dust. I. Comparison of analytic methods and their value as estimators of potential exposure.

The presence of viable mold propagules in house dust was investigated by 10 different analytic methods, in order to determine to what extent different results are obtained when different analytic methods are used. Moreover, the value of this measurement as an estimator of the potential exposure to fungi in epidemiologic studies was assessed. Floor and mattress dust was sampled in 60 homes in The Netherlands during autumn 1990. For investigation of the variability in time, sampling was repeated in 20 homes after 6 weeks. Each analytic method is characterized by a unique combination of culture medium, suspension medium, and dilution step. The highest mean number of colony-forming units (CFU)/g dust was obtained by suspension of at least 100 mg dust in a peptone or sucrose solution in a ratio of 1:50 (w/w), followed by 10-fold dilution and plating on DG18 agar (geometric mean (GM) approximately 60,000 CFU/g dust). The lowest mean number of CFU/g dust was obtained by direct plating of 30 mg dust on V8 agar (GM approximately 5300 CFU/g dust). The mean coefficient of variation of duplicate analyses varied from 11%, for suspension in sucrose and plating on DG18 agar, to 27%, for suspension and dilution in sucrose in combination with V8 agar. The highest mean number of species isolated was obtained by direct plating of 30 mg dust on DG18 agar (mean number of species: 17). Suspension and dilution on DG18 or V8 agars yielded an average of approximately six species. In duplicate analyses, the mean percentage of agreement for the species isolated varied from approximately 35%, for suspension and dilution, to 60%, for direct plating.(ABSTRACT TRUNCATED AT 250 WORDS)

Colony Count, Microbial↗
PubMed1979

Smoking impairs long-term dust clearance from the lung.

The time for the long-term clearance of dust from human lungs was measured. Three heavy cigarette smokers and nine nonsmokers inhaled a harmless trace amount of magnetic dust, Fe3O4. From periodic measurements with a sensitive magnetic detector of the amount of this dust remaining in the lungs, a clearance curve was determined for each subject. This magnetic tracer method allows clearance to be safely followed for a much longer time than with radioactive tracer methods. The dust clearance in the smokers is considerably slower than in the nonsmokers. After about a year, 50 percent of the dust originally deposited remained in the lungs of the smokers whereas only 10 percent remained in the lungs of the nonsmokers. The smokers therefore retained five times more dust than the nonsmokers. This impaired clearance of Fe3O4 suggests impaired clearance in smokers of other dusts, such as toxic occupational and urban dusts. The higher retention of these dusts may contribute to the higher incidence of lung diseases in smokers.

Adult↗
PubMed1994

Prediction of the comparative intensity of pneumoconiotic changes caused by chronic inhalation exposure to dusts of different cytotoxicity by means of a mathematical model.

A multicompartmental mathematical model has been used to simulate variations in the cytotoxicity of dusts in the kinetics of the retention, in the pulmonary region and tracheobronchial lymph nodes, of practically insoluble quartzite and titanium dioxide dust particles deposited on the free surfaces of the acini from alveolar air. Experiments with these dusts were conducted on rats exposed to virtually the same dust concentrations in the air for an experimental period of 20 weeks and a period of 10 weeks after exposure. Satisfactory approximation to the experimental data on the retention of these dusts is obtained by using the model parameters that depend either on damage to lung macrophages by phagocytosed particles or on the response of the host organism to this damage by enhanced recruitment of neutrophilic leucocytes; all the other variables of the model being unchanged. The values of the "action integral" computed from this model and multiplied by the index of comparative cytotoxicity of particles in vitro satisfactorily approximate to quantitative differences in the intensity of pneumoconioses caused by the dusts under study by the end of the experimental period. On the whole, the results of the mathematical model agree with the hypothesis that the cytotoxicity of particles plays a key part in both the process of retention of dust in the lung parenchyma and lung associated lymph nodes, and the pathological process caused by the retained dust. Thus given the factors and conditions on which the deposition of practically insoluble dusts in the pulmonary region depends, it is necessary to take into account the multiplicative nature of these two effects of cytotoxicity when predicting the comparative risk of pneumoconiosis.

Animals↗
PubMed2000

Laryngeal and hypopharyngeal cancers and occupational exposure to formaldehyde and various dusts: a case-control study in France.

OBJECTIVES: A case-control study was conducted in France to assess possible associations between occupational exposures and squamous cell carcinomas of the larynx and hypopharynx. METHODS: The study was restricted to men, and included 201 hypopharyngeal cancers, 296 laryngeal cancers, and 296 controls (patients with other tumour sites). Detailed information on smoking, alcohol consumption, and lifetime occupational history was collected. Occupational exposure to seven substances (formaldehyde, leather dust, wood dust, flour dust, coal dust, silica dust, and textile dust) was assessed with a job exposure matrix. Exposure variables used in the analysis were probability, duration, and cumulative level of exposure. Odds ratios (ORs) with their 95% confidence intervals (95% CIs) were estimated by unconditional logistic regression, and were adjusted for major confounding factors (age, smoking, alcohol, and when relevant other occupational exposures). RESULTS: Hypopharyngeal cancer was found to be associated with exposure to coal dust (OR 2.31, 95% CI 1.21 to 4.40), with a significant rise in risk with probability (p<0.005 for trend) and level (p<0.007 for trend) of exposure. Exposure to coal dust was also associated with an increased risk of laryngeal cancer (OR 1.67, 95% CI 0.92 to 3.02), but no dose-response pattern was found. A significant relation, limited to hypopharyngeal cancer, was found with the probability of exposure to formaldehyde (p<0.005 for trend), with a fourfold risk for the highest category (OR 3.78, 95% CI 1.50 to 9.49). When subjects exposed to formaldehyde with a low probability were excluded, the risk also increased with duration (p<0.04) and cumulative level of exposure (p<0.14). No significant association was found for any other substance. CONCLUSION: These results indicate that exposure to formaldehyde and coal dust may increase the risk of hypopharyngeal cancer.

Aged↗
PubMed2001

Cumulative exposure to dust causes accelerated decline in lung function in tunnel workers.

OBJECTIVES: To examine whether underground construction workers exposed to tunnelling pollutants over a follow up period of 8 years have an increased risk of decline in lung function and respiratory symptoms compared with reference subjects working outside the tunnel atmosphere, and relate the findings to job groups and cumulative exposure to dust and gases. METHODS: 96 Tunnel workers and a reference group of 249 other heavy construction workers were examined in 1991 and re-examined in 1999. Exposure measurements were carried out to estimate personal cumulative exposure to total dust, respirable dust, alpha-quartz, oil mist, and nitrogen dioxide. The subjects answered a questionnaire on respiratory symptoms and smoking habits, performed spirometry, and had chest radiographs taken. Radiological signs of silicosis were evaluated (International Labour Organisation (ILO) classification). Atopy was determined by a multiple radioallergosorbent test (RAST). RESULTS: The mean exposure to respirable dust and alpha-quartz in tunnel workers varied from 1.2-3.6 mg/m3 (respirable dust) and 0.019-0.044 mg/m3 (alpha-quartz) depending on job task performed. Decrease in forced expiratory volume in 1 second (FEV1) was associated with cumulative exposure to respirable dust (p<0.001) and alpha-quartz (p=0.02). The multiple regression model predicted that in a worker 40 years of age, the annual decrease in FEV1 would be 25 ml in a non-exposed non-smoker, 35 ml in a non-exposed smoker, and 50-63 ml in a non-smoking tunnel worker (depending on job). Compared with the reference group the odds ratio for the occurrence of new respiratory symptoms during the follow up period was increased in the tunnel workers and associated with cumulative exposure to respirable dust. CONCLUSIONS: Cumulative exposures to respirable dust and alpha-quartz are the most important risk factors for airflow limitation in underground heavy construction workers, and cumulative exposure to respirable dust is the most important risk factor for respiratory symptoms. The finding of accelerated decline in lung function in tunnel workers suggests that better control of exposures is needed.

Adult↗
PubMed1992

Dust- and endotoxin-related respiratory effects in the animal feed industry.

A cross-sectional study of 315 animal feed workers was undertaken in 14 animal feed mills in the Netherlands. Primary aims were to explore relationships between exposure to organic dust and respiratory symptoms and chronic lung function changes. The study comprised monitoring dust and endotoxin exposure, spirometric lung function measurements (FVC, FEV1, mean midexpiratory flow, and flow-volume parameters) and a questionnaire for respiratory symptoms. The exposure was measured in two periods, during spring and autumn. The average 8-h personal inspirable dust exposure was 9 mg/m3 grain dust (range, 0.2 to 150 mg/m3) and 25 ng/m3 endotoxin (range, 0.2 to 470 ng/m3) based on 530 personal dust measurements. On the basis of these measurements and the occupational history of the workers, the number of years "worked in dust" and an estimate of the cumulative dust and endotoxin exposure were calculated. The prevalence of most chronic respiratory symptoms tended to decrease with increasing years of exposure. The "healthy worker effect" is probably responsible for this finding. In general, a strong negative association between most of the exposure variables and lung function was found. The endotoxin exposure was more strongly related to decreases in lung function than the dust exposure. The estimated effects of an average (cumulative) endotoxin exposure on lung function were greater, with a higher statistical significance, than for an exposure to dust. These results suggest that endotoxin exposure is an important factor in the development of respiratory impairment. The lung function changes occur at endotoxin levels ranging from 0.2 to 470 ng/m3.

Adult↗
PubMed1983

Variations in the histological patterns of the lesions of coal workers' pneumoconiosis in Britain and their relationship to lung dust content.

The lungs of 490 British coal miners were examined for comparisons of the lesions of coal workers' pneumoconiosis with lung dust content and dust exposure. Variations were found in histological appearances that formed a range, the extremes of which indicated two separate patterns of disease. In men from high rank collieries, whose lung dust had a high carbon content and little ash, most of the nodules of simple pneumoconiosis were evenly pigmented with dust, and where progressive massive fibrosis (lesions greater than 1 cm in diameter) had developed, this appeared to be by the enlargement of a single lesion. In men from low rank collieries where the ash content of lung dust was high, the centers of the nodules were often free of dust particles and in extreme cases these lesions were very similar to silicotic nodules. If PMF developed in these cases, it often appeared to be by the fusion of closely spaced groups of smaller nodules. While there appeared to be little difference between the lung dust composition of men from high rank collieries and the dust to which they had been exposed, in men from low rank collieries the proportion of the noncoal minerals in the lungs was usually higher than it had been in the mine dust. This indicated some form of differential retention of these components, which was progressively more marked in men with the more serious grades of pneumoconiosis.

Coal Mining↗
PubMed2002

Lymphocyte activation after exposure to swine dust: a role of humoral mediators and phagocytic cells.

Exposure to swine dust causes intense airway inflammation with multifold increase in inflammatory cells and secretion of pro-inflammatory cytokines. This in vitro study focuses on the swine-dust activation of lymphocytes in whole blood, in phagocyte-depleted whole blood and in peripheral blood mononuclear cells (PBMC), in order to investigate whether phagocytic cells and/or soluble mediators are involved in the activation of T-cells following exposure to organic dust from a swine confinement house. T-cell activation was analysed by flow cytometry with double staining for CD3 and the activation marker CD69. Swine dust (50 microg) incubated (24 h) with heparinized whole blood was shown to activate 27.6% of the T-cells, while swine dust incubated with whole blood depleted from phagocytic cells or PBMC only activated 4.5%, and 4.8% of the T-cells, respectively. Plasma separated from whole blood preincubated with swine dust for 24 h stimulated as much as 32.4% of PBMC T-cells and contained high levels of interleukin (IL)-12 (14 pg x mL) and interferon (IFN)-gamma (2284 pg x mL(-1)), while plasma from PBMC incubated with swine dust contained low levels of IL-12 (2 pg x mL(-1)) and IFN-gamma (196 pg x mL(-1)). This study demonstrates that activation of T-cells by organic dust from a swine confinement building seems to require phagocytic cells, most likely acting through the release of soluble mediators. Also, conditioned plasma from swine-dust exposed whole blood, which was capable of activating T-cells, contained high concentrations of interleukin-12 and interferon-y.

Adult↗