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PubMed2005

High exposure to respirable dust and quartz in a labour-intensive coal mine in Tanzania.

Labour-intensive mines are numerous in several developing countries, but dust exposure in such mines has not been adequately characterized. The aim of this study was to identify and quantify the determinants of respirable dust and quartz exposure among underground coal mine workers in Tanzania. Personal respirable dust samples (n = 134) were collected from 90 underground workers in June-August 2003 and July-August 2004. The development team had higher exposure to respirable dust and quartz (geometric means 1.80 and 0.073 mg m(-3), respectively) than the mining team (0.47 and 0.013 mg m(-3)), the underground transport team (0.14 and 0.006 mg m(-3)) and the underground maintenance team (0.58 and 0.016 mg m(-3)). The percentages of samples above the threshold limit values (TLVs) of 0.9 mg m(-3) for respirable bituminous coal dust and 0.05 mg m(-3) for respirable quartz, respectively, were higher in the development team (55 and 47%) than in the mining team (20 and 9%). No sample for the underground transport team exceeded the TLV. Drilling in the development was the work task associated with the highest exposure to respirable dust and quartz (17.37 and 0.611 mg m(-3), respectively). Exposure models were constructed using multiple regression model analysis, with log-transformed data on either respirable dust or quartz as the dependent variable and tasks performed as the independent variables. The models for the development section showed that blasting and pneumatic drilling times were major determinants of respirable dust and quartz, explaining 45.2 and 40.7% of the variance, respectively. In the mining team, only blasting significantly determined respirable dust. Immediate actions for improvements are suggested to include implementing effective dust control together with improved training and education programmes for the workers. Dust and quartz in this underground mine should be controlled by giving priority to workers performing drilling and blasting in the development sections of the mine.

Coal Mining↗
PubMed2006

Mechanisms of particle-induced pulmonary inflammation in a mouse model: exposure to wood dust.

Repeated airway exposure to wood dust has long been known to cause adverse respiratory effects such as asthma and chronic bronchitis and impairment of lung function. However, the mechanisms underlying the inflammatory responses of the airways after wood dust exposure are poorly known. We used a mouse model to elucidate the mechanisms of particle-induced inflammatory responses to fine wood dust particles. BALB/c mice were exposed to intranasally administered fine (more than 99% of the particles had a particle size of < or = 5 microm, with virtually identical size distribution) birch or oak dusts twice a week for 3 weeks. PBS, LPS, and titanium dioxide were used as controls. Intranasal instillation of birch or oak dusts elicited influx of inflammatory cells to the lungs in mice. Enhancement of lymphocytes and neutrophils was seen after oak dust exposure, whereas eosinophil infiltration was higher after birch dust exposure. Infiltration of inflammatory cells was associated with an increase in the mRNA levels of several cytokines, chemokines, and chemokine receptors in lung tissue. Oak dust appeared to be a more potent inducer of these inflammatory mediators than birch dust. The results from our in vivo mouse model show that repeated airway exposure to wood dust can elicit lung inflammation, which is accompanied by induction of several proinflammatory cytokines and chemokines. Oak and birch dusts exhibited quantitative and qualitative differences in the elicitation of pulmonary inflammation, suggesting that the inflammatory responses induced by the wood species may rise via different cellular mechanisms.

Animals↗
PubMed1977

House dust mites in Iran.

In the Caspian Sea region of Iran asthma seems closely related to house dust allergy. Since a high proportion of house dust sensitive patients appear to be sensitive to house dust mites, an investigation was carried out to determine the occurrence, distribution and abundance of these species in Iranian house dust in order to assess their role and clinical importance in house dust allergy in Iran. Thirty-five samples of house dust collected from houses in the Caspian Sea region and five samples from other areas were examined for mites. The three pyroglyphid species Dermatophagoides pteronyssinus, D. farinae and Euroglyphus maynei, reported by European and Japanses workers to be common in house dust and to be a major source of house dust allergens, were found to occur in Iranian house dust and to account for nearly two-thirds of the total mit population present in the dust. Dermatophagoidex pteronyssinus was the most frequent and most numerous species recorded, occurring in 90% of the samples examined and forming 94% of the pyroglyphid and 60% of the total mite population. The frequency with which house dust mites were found in the Iranian Caspian Sea region coupled with the relatively high frequency of allergic bronchial asthma in this area suggests that they may well be an important precipitating factor in asthma in Iran.

Animals↗
PubMed2004

Effects of furniture polish on release of cat allergen-laden dust from wood surfaces.

UNLABELLED: The purpose of this study was to evaluate the effects of furniture polish (FP) on the release of cat allergen (Fel d 1)-laden dust from wood surfaces and decay of Fel d 1 in dust over time. About 2 g of sieved (150 microm screen) allergen-laden dust was introduced as an aerosol into an experimental chamber by a Pitt-3 generator and allowed to settle onto two finished wood surfaces pre-treated with either distilled water (DW) or FP. After 24 h, each surface was vacuumed into separate plastic cassettes loaded with 37 mm diameter, 0.4 microm pore, polycarbonate filters. The recovered dust was weighed, extracted in phosphate-buffered saline, and assayed for Fel d 1 content using a two-site monoclonal antibody ELISA. After vacuuming, the remaining dust on the wood surfaces was wiped up with a water-moistened swab. The dusts were extracted from the swabs and assayed by ELISA for Fel d 1. More Fel d 1 was recovered by vacuuming from DW-pre-treated surfaces than from FP pre-treated surfaces (100% vs. 69 +/- 66%). On the contrary, more residual Fel d 1 (>99.9%) on the vacuumed surfaces was recovered from FP than from DW pre-treated surfaces by wet swabs. The concentration of Fel d 1 in dust did not change significantly at room temperature over 80 days. In conclusion, FP on wood surfaces makes dust stick to the surface, which likely reduces the release of allergen-laden dust from the wood surface. PRACTICAL IMPLICATIONS: Re-aerosolization of cat allergen-laden dusts from wood surfaces (e.g. wood floor or furniture) significantly increases the concentration of airborne cat allergens. Our study indicates that exposure to airborne cat allergens might be reduced by surface treatment with commercially available FP because cat allergen-laden dusts stuck more tightly to the wood surface treated with FP.

Air Pollution, Indoor↗
PubMed1976

Counteraction of poly(4-vinylpyridine-n-oxide) on the depression of viral interferon induction by coal dust.

The depressive activity of coal dust on interferon induction by influenza was markedly subverted when either coal dust or LLC-MK2 cell monolayers were pretreated with poly (4-vinylpyridine-N-oside). The polymer alone neither induced interferon synthesis, inhibited viral induction of interferon, influenced viral multiplication, nor affected cellular-induced resistance by interferon. Absorption of the polymer to coal dust not only occurred at a more rapid rate than to cell monolayers, but also less polymer was required to pretreat coal dust than cell monolayers to achieve comparable amelioration of interferon production. The polymer effectively negated the adverse activity of coal dust particles, irrespective of the latter's size (is less than 2.0 to 74.0 mum). Virus multiplication in the presence of coal dust=treated cell monolayers attained a level that was twofol higher than that noted with either polymer-pretreated coal dust or polymer-pretreated cell monolayers. Interferon production was almost completely inhibited in the presence of coal dust; pretreating coal dust or cells with the polymer abrogated this inhibitory activity of coal dust. It is tentatively suggested that coal dust particles per se directly interact with cell membranes to subvert interferon induction and that the formation of an absorbed polymerlayer on these complexes prevents their interaction.

Coal↗
PubMed1991

The protective role of zinc in the toxic action of coal dust upon mouse macrophages.

Macrophages from mice were cultured at 37 degrees C with 1640 medium containing 10% bovine serum. The macrophage suspension was made from 50 Swiss mice and was cultured in the following groups: control group; coal dust group (with added coal dust particles (10 micrograms/ml) smaller than 4 microns diameter); subdivided zinc-coal dust group (as coal dust group with zinc added in three different concentrations--namely, 10 ppm, 30 ppm, and 60 ppm). Cells were examined by light microscopy. Obvious differences were found in the rate of cell deaths between the coal dust group and the zinc-coal dust group after culture for 48 hours. The cell membranes were ruptured after culturing with coal dust, and the presence of zinc appeared in some degree to protect cell membranes from damage caused by the dust. Staining the cells with Gomori's modified method, showed that acid phosphatase particles in the zinc-coal dust group were more numerous than in the coal dust group. The results indicate that the trace element zinc may play an important part in protecting against the cytotoxic action of coal dust.

Acid Phosphatase↗
PubMed1991

Injurious effects of wool and grain dusts on alveolar epithelial cells and macrophages in vitro.

Epidemiological studies of workers in wool textile mills have shown a direct relation between the concentration of wool dust in the air and respiratory symptoms. Injurious effects of wool dust on the bronchial epithelium could be important in causing inflammation and irritation. A pulmonary epithelial cell line in vitro was therefore used to study the toxic effects of wool dust. Cells of the A549 epithelial cell line were labelled with 51Cr and treated with whole wool dusts and extracts of wool, after which injury was assessed. Also, the effects of grain dust, which also causes a form of airway obstruction, were studied. The epithelial injury was assessed by measuring 51Cr release from cells as an indication of lysis, and by monitoring cells which had detached from the substratum. No significant injury to A549 cells was caused by culture with any of the dusts collected from the air but surface "ledge" dust caused significant lysis at some doses. Quartz, used as a toxic control dust, caused significant lysis at the highest concentration of 100 micrograms/well. To determine whether any injurious material was soluble the dusts were incubated in saline and extracts collected. No extracts caused significant injury to epithelial cells. A similar lack of toxicity was found when 51Cr labelled control alveolar macrophages were targets for injury. Significant release of radiolabel was evident when macrophages were exposed to quartz at concentrations of 10 and 20 micrograms/well, there being no significant injury with either wool or grain dusts. These data suggest that neither wool nor grain dust produce direct injury to epithelial cells, and further studies are necessary to explain inflammation leading to respiratory symptoms in wool and grain workers.

Animals↗
PubMed1996

Bacterial and fungal flora of dust deposits in a pig building.

OBJECTIVE: The purpose of the study was to investigate the bacterial and fungal flora of dust deposits in a newly built pig grower finisher building. Viable bacterial counts and microbial species found in a barn which had never housed pigs were compared with those in a barn housing 144 pigs. METHODS: The quantitative streak plate method was used to measure viable bacterial counts on nutrient agar or sheep blood agar. Viable bacterial counts of the dust deposits were expressed as the number of colony forming units (CFUs)/mg of dust. Gram positive cocci and Gram negative bacilli were identified by an automated system. Identifications with a confidence interval > 90% were accepted at the species level. Fungi were identified to the genus level with slide culture preparations on cereal agar. RESULTS: The lowest viable bacterial count (4.8 x 10(4)/mg of dust) was found in the barn with no pigs. In the barn with pigs the highest viable bacterial count (2.1 x 10(6)/mg of dust) was in dust from the top of a partition close to pig activity. Six species of bacteria or fungi were found in dust from the room with no pigs, whereas 22 different microorganisms were detected in dust from the room with pigs. With the exception of Enterobacter agglomerans no other species of the family Enterobacteriaceae was found in dust deposits in this new pig building. Twelve species of Gram positive bacteria were found in the room housing pigs. CONCLUSIONS: The pig is not only a source but also a disperser of airborne bacteria in pig buildings. Speciation of the microbial flora in dust from the pig building suggests that many of the microorganisms were either of human or environmental origin. Nevertheless as some of these microorganisms are known opportunistic pathogens or allergens and because of the documented increased incidence of chronic respiratory symptoms in pig workers, precautions to reduce inhalation of microbial or dust particles by pig workers seem prudent.

Animals↗
PubMed1999

Ventilatory function and personal breathing zone dust concentrations in Lancashire textile weavers.

BACKGROUND: To report findings on ventilatory function and estimations of concentrations of personal breathing zone dust in Lancashire textile weavers. Weaving room dust is considered to be less harmful than that encountered in the cardroom or spinning room and weavers are generally thought to have less respiratory disability than carders or spinners. However, this occupational group has not been extensively studied. METHODS: Each person was given a respiratory symptom questionnaire (modified Medical Research Council, UK, questionnaire on respiratory diseases). Ventilatory function tests, forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) were performed on each person. A representative sample of workers from each occupational group underwent dust sampling in their personal breathing zone. Dust concentrations and ventilatory tests were analysed statistically with the Student's t test, Pearson's correlation coefficient, and forward step regression for relations with symptoms and environmental factors. Significance was p > or = 0.05. RESULTS: The FEV1 and FVC were reduced in workers with respiratory symptoms (non-specific chest tightness, shortness of breath, persistent cough, and wheezing) as well as in preparation room workers, current and former smokers, Asians, those working with predominantly cotton fibre (> 50% cotton) and starch size. Mean total dust concentration (pd1) in the personal breathing zone was 1.98 mg/m3. The corresponding value for total dust with large fibres lifted off the filter paper (pd2) was 1.55 mg/m3. There was a strong correlation (r = 0.94, p < 0.0001) between pd1 and pd2. Non-specific chest tightness was predicted by low dust concentrations and persistent cough by high dust concentrations. On regression analysis, impairment of ventilatory function (FEV1, FVC) was predicted by smoking, male sex, age, not working in the weaving shed, not being white, and personal dust concentrations. CONCLUSIONS: The FEV1 and FVC were impaired in smokers and those exposed to high dust concentrations in the personal breathing zone. Symptoms were inconsistently related to dust concentrations in the personal breathing zone.

Dust↗
PubMed2003

Inflammatory potential of dust from schools and building related symptoms.

AIMS: To test whether the inflammatory potential of dust samples might be used to differentiate schools with high and low prevalence of building related symptoms (BRS) among the occupants. METHODS: Ten schools with high prevalence of BRS and 10 schools with low prevalence were selected. Dust collected from floors, horizontal surfaces, and exhaust outlets was tested at five concentrations on the lung epithelial cell line A549. The potency of the dust (PF) to stimulate IL-8 secretion was calculated from the initial linear part of the dose-response curves. The organic fraction of the dust samples was determined by incineration. RESULTS: The schools with low prevalence of symptoms had a BRS% of 4.4-11.0 and the schools with high prevalence a BRS% of 19.6-31.9. The PF of floor dust and surface dust correlated, and the PF was associated with the organic content of the dust. The schools with low prevalence of symptoms had a significantly lower PF than the schools with high prevalence. Using the cut point value of 4.5 ng IL-8/mg floor dust, significantly more high prevalence schools were found above the cut point than below. CONCLUSION: The PF of the floor dust samples correlated significantly with the prevalence of symptoms in the schools. The content of endotoxin and microorganisms did not seem to explain the inflammatory potential of the dust or BRS, and the substances in the dust causing the inflammatory potential are presently unknown.

Adolescent↗
PubMed1985

Small airways disease and mineral dust exposure. Prevalence, structure, and function.

Previously we described a lesion of the small airways that appears related to mineral dust exposure and is found in asbestos and nonasbestos dust-exposed populations. To determine the usefulness of this lesion as a marker for mineral dust exposure, and to determine whether it produces functional consequences, we examined a group of 53 workers who had been either hard rock miners or in the asbestos, construction, and shipyard industries. The specific lesion (mineral dust airways disease (MDAD] consists of marked fibrosis and pigmentation of the respiratory bronchioles and was found in 13 of 53 workers with dust exposure, but only in 1 of 121 without dust exposure. Compared with age and smoking-matched dust-exposed control subjects, patients with this lesion had significant abnormalities of forced expiratory volume in one second (FEV1), forced expiratory flow during the middle half of the forced vital capacity (FEF25-75), vital capacity (VC), and nitrogen washout. In addition to fibrosis in the walls of respiratory bronchioles, these patients also had significant increases of fibrosis in the walls of membranous bronchioles, indicating that changes in the small airways are widespread in this subset of workers. We conclude that markedly abnormal small airways are present in some workers with mineral dust exposure; pathologic observation of this lesion is a good indicator of dust exposure, and its presence is associated with abnormalities of air flow greater than those induced by smoking alone. The presence of this lesion in only a portion of dust-exposed workers may account for contradictory results in past studies that attempted to demonstrate air flow abnormalities associated with mineral dust exposure.

Aged↗
PubMed2003

Differential responses of rat alveolar macrophages to carpet dust in vitro.

Epidemiological studies of workers in carpet weaving units in carpet industries have shown a direct relation between the concentration of carpet dust in the air and respiratory symptoms. To predict the health risk of carpet weavers, this preliminary study was conducted to evaluate the toxic potential of different types of workplace dust by using alveolar macrophages (AMs). Several parameters were observed for cytotoxicity such as cell viability, the release of lactate dehydrogenase (LDH) in rat AMs treated with different concentration of carpet dust and haemolytic potential of erythrocytes. In addition, reactive oxygen/nitrogen species-inducing effects of carpet dust were assessed by nitric oxide (NO), reduced glutathione (GSH) release and hydrogen peroxide (H2O2) generation in AMs. Results of cell viability and hemolytic assay showed a direct correlation between increasing the dust concentration with enhancing the toxic effect. Knotted and tufted carpet dust increases the release of LDH, NO, GSH and H2O2 production with increasing dust concentration. Present observations have revealed that dusts collected from tufted carpet weaving units exhibited more toxicity to AMs than knotted carpet dust. These data further suggest that injurious effects of carpet dust to AMs could pave a way to evaluate the toxic potential of the different types of workplace dusts and component(s) involved in it.

Animals↗
PubMed2005

Feasibility of using subject-collected dust samples in epidemiologic and clinical studies of indoor allergens.

Studies of indoor allergen exposures are often limited by the cost and logistics of sending technicians to homes to collect dust. In this study we evaluated the feasibility of having subjects collect their own dust samples. The objectives were to compare allergen concentrations between subject- and technician-collected samples and to examine the sample return rate. Using a dust collection device and written instructions provided to them by mail, 102 subjects collected a combined dust sample from a bed and bedroom floor. Later the same day, a technician collected a side-by-side sample. Dust samples were weighed and analyzed for the cat allergen Fel d 1 and the dust mite allergen Der p 1. Fifty additional subjects who were enrolled by telephone were mailed dust collection packages and asked to return a dust sample and questionnaire by mail. A technician did not visit their homes. Correlations between subject- and technician-collected samples were strong for concentrations of Fel d 1 (r = 0.88) and Der p 1 (r = 0.87). With allergen concentrations dichotomized at lower limits of detection and clinically relevant thresholds, agreements between methodologies ranged from 91 to 98%. Although dust weights were correlated (r = 0.48, p < 0.001), subjects collected lighter samples. Among the group of 50 subjects, 46 returned a dust sample and completed questionnaire. The median number of days to receive a sample was 15. With some limitations, subject-collected dust sampling appears to be a valid and practical option for epidemiologic and clinical studies that report allergen concentration as a measure of exposure.

Adult↗
PubMed2001

Pharmacologic properties of brewery dust extracts in vitro.

STUDY OBJECTIVES: To study the effects of extracts of brewery dust on isolated guinea pig tracheal smooth muscle in vitro. DESIGN: Parallel pharmacologic intervention on guinea pig tracheal rings that were obtained from the same animal. SETTING: Mount Sinai School of Medicine, Department of Pulmonary Medicine. MATERIAL: The isolated guinea pig tracheal tissue of 18 guinea pigs. INTERVENTIONS: Pretreatment of guinea pig rings by mediator-modifying agents before challenge with the brewery dust extracts. MEASUREMENTS AND RESULTS: The effect of brewery dust extracts on isolated guinea pig tracheal smooth muscle was studied using water-soluble extracts of dust obtained from brewery materials, including hops, barley, and brewery yeast. Dust extracts were prepared as a 1:10 (wt/vol) aqueous solution. Dose-related contractions of nonsensitized guinea pig tracheas were demonstrated using these extracts. The dust extracts contained significant quantities of bacterial components (eg, endotoxin and n-formyl-methionyl-leucyl-phenylalanine), but these agents were not thought to contribute directly to the constrictor effect of the dusts. Pharmacologic studies were performed by pretreating guinea pig tracheal tissue with the following drugs known to modulate smooth muscle contraction: atropine; indomethacin; pyrilamine; LY171883; nordihydroguaiaretic acid; captopril; thiorphan; verapamil; and TMB8. The constrictor effects of the dust extracts were inhibited by a wide variety of agents, the patterns of which depended on the dust extract. Atropine consistently and strikingly reduced the contractile effects of these extracts. These observations may suggest an interaction of the extracts with parasympathetic nerves or, more directly, with muscarinic receptors. The inhibition of contraction by the blocking of other mediators was less effective and varied with the dust extract. CONCLUSIONS: We suggest that brewery dust extracts cause a dose-related airway smooth muscle constriction by nonimmunologic mechanisms involving a variety of airway mediators and, possibly, cholinergic receptors. This effect is not dependent on presensitization of the guinea pigs.

Animals↗
PubMed2001

Risk of exposure to house dust pyroglyphid mites in Poland.

During the period of 1989-2000, 335 house dust samples were collected from dwellings at 27 different localities in Poland. Mite allergen exposure was measured in house dust samples collected by performing of mite taxa determination and measuring of the mite allergen levels by a semiquantitative guanine method (Acarex(R) test). Mites were found in 158 of the samples examined (47.2%). A total 3,714 mites were isolated and 15 species identified, including four species from the family Pyroglyphidae (house dust mites). Among them, Dermatophagoides farinae (DF) was predominant (approximately 67% of the total count), followed by D. pteronyssinus (DP) (17.6%) and Euroglyphus maynei (EM) (1.6%). Hirstia chelidonis (HCh) was found for the first time in house dust samples in Poland. DF was predominant in Iwonicz-Zdroj (96.6%), Katowice (91.8%), Sosnowiec (89.4%), Chorzow (94.8%), Bytom (50.9%), Swiêtochlowice (96.7%) and generally in Upper Silesia (88.2%), whereas DP dominated in Lod (92.9%), Wodzislaw (80.9%), Krakow (45.6%) and Bielsko-Biala (24.8%). Only 14.3% of the mites collected were alive. Total mean number of domestic mites per gram of dust (in all samples examined) was 204.1 +/- 1079.8. The greatest number of mites per 1 gram of dust was 14,971.4. Mite densities and levels of mite allergens (expressed as Acarex test steps) in samples from beds, floors and upholstery furnitures at particular localities in Poland, and in dwellings of atopic versus non-atopic subjects were compared. Highest mite concentrations were usually found in dust from beds, carpets and shutters. D. farinae was distinctly more abundant both per 1 gram of dust and per 1 sample than the species D. pteronyssinus. Other pyroglyphid mites, E. maynei and H. chelidonis, occurred in very small numbers. No significant differences were found between the counts of mites (total and live) in the dwellings of atopic and non-atopic persons. Approximately 49.5% of samples showed positive levels of the mite allergens (Acarex test steps). An influence of some abiotic indoor factors on the mite prevalence in the examined dwellings was analysed separately in relation to samples of bed dust, floor dust and dust from upholstery furnitures. The density of mites was influenced mainly by the type of heating, temperature, type of sleeping accommodation, type of floor or furniture, sampling method, and type of building, whereas levels of the mite allergens were associated with the mite density, relative humidity, month, sampling method, type of building and type of heating.

Air Pollution, Indoor↗
PubMed2002

[Changes in bronchoalveolar lavage fluid of rats exposed to metal grinding dusts].

OBJECTIVE: To investigate the effects of composite grinding dusts on rat respiratory system. METHODS: Rats were administrated with grinding dusts by intratracheal injection. After 2 weeks, the total numbers of cells, the percentage of differential cell, the survival rate of cell, and the activity of lactate dehydrogenase(LDH) and alkaline phosphatase(ALP) in bronchoalveolar lavage fluid were analyzed. RESULTS: Along with increasing concentration of grinding dusts, the total number of cells in lavage also increased, and was more than that in quartz group. Compared with control group, the percentage of neutrophil in lavage of rats treated with grinding dust and quartz significantly increased and meanwhile that of macrophage significantly decreased[PMN: quartz group (33.83 +/- 4.54)%; grinding dusts group (26.50 +/- 3.99)%, (36.00 +/- 3.58)%, (38.00 +/- 2.10)% at 10, 25, 50 mg/ml respectively. Macrophages: quartz group (62.17 +/- 4.54)%; grinding dusts group (70.83 +/- 3.66)%, (60.83 +/- 2.14)%, (58.17 +/- 2.48)%] while those in control group were (2.83 +/- 0.75)%, (95.67 +/- 1.21)% respectively. The cell survival rate in lavage in control group was 80%, but that in grinding dust and TiO2 group significantly decreased(P < 0.01). The activity of LDH and ALP in all rats treated with dusts obviously increased, and there was significant difference compared with control group(P < 0.01 or P < 0.05). Furthermore, there was significant difference between grinding dust group and quartz group, and between grinding dust group and TiO2 group respectively. CONCLUSION: Metal grinding dust is very harmful to rat's lung cells and may cause fibrogenesis in the lungs.

Alkaline Phosphatase↗
PubMed1989

[Pathogenic effects of titanium dioxide dust on the lung of dogs--a histopathological and ultrastructural study].

Titanium dioxide (TiO2) dust has generally been regarded as a "nuisance dust" in experimental animals and men. In this experiment, 16 dogs were exposed intratracheally to TiO2 dust for 9-15 months. The scanning electron microscopy with energy dispersive analysis of X-ray (SEM-EDAX), performed to identify the elemental composition of dust particles used in the study and in the focal lesions of the lungs, showed that dust particles were nearly pure titanium. Dust in the lung deposited mainly in the respiratory bronchioles and adjacent alveoli, with many alveoli filled by compacted dust particles. The pulmonary responses consisted of slight alveolitis, centrilobular emphysema, focal collapse of alveoli, and fibroblast hyperplasia with a few collagen fibres surrounding some of the TiO2-dust foci. Electron microscopically, many alveolar macrophages with intact nuclei contained a great amount of dust particles in their lysosomes, and in the dust foci, most of type I pneumocytes disappeared and type I pneumocytes showed hyperplasia. The alveolar subepithelial basement membrane were markedly thickened and bundles of collagen fibres were formed in the interstice. These findings suggest that TiO2 dust is one of the sorts which probably induce mild lung fibrosis in case a large amount is deposited in the lung tissue.

Animals↗
PubMed1988

Pulmonary injury in laboratory animals induced by Huai-Nan coal mine respirable dust.

The BAL technique was used to assess the pulmonary injury of coal dust and rock dust in Huai-Nan coal mine in Anhui Province. Dust suspended in saline and dust-free supernatant were instilled intratracheally to Wistar rats and Syrian hamsters. Saline was used in treating controls. The animals were sacrificed 24 h after treatment, their lungs were lavaged, and pulmonary damage was evaluated by cellular and biochemical assays of lavage fluid. Pulmonary injury was expressed by the cell toxicity index (CTI). CTI is the product of the number of times of meaningful parameters for treated groups compared to controls (LDH, acid phosphatase, and polymorphonuclear neutrophils in this case). The CTI values were found to be 5.19, 2.28, and 5.15 for rock dust, coal dust, and Shanghai suspended particulates, respectively. The toxicity of rock dust is higher than that of coal dust, but is similar to that of Shanghai suspended particulates. The cell toxicity of dust suspension solution is higher than that of dust-free supernatant. CTI can be used as an indicator of the relative toxicity of respirable dusts in in vivo studies.

Acid Phosphatase↗