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PubMed2001

[Dust deposition and its measurement by 137Cs in the Gonghe Basin, Qinghai Province, China].

Through the dust observation at three sites in the Gonghe Basin, Qinghai Province, China and 137Cs analysis of dust samples, the 137Cs technique is firstly used to study the dust deposition by storm. The rate of dust deposition and its monthly distribution were determined and the dust source traced by 137Cs. It is apparent that the 137Cs model for accumulation rate must be modified because of the 137Cs redistribution from dust gain. These tentative results may be have some significant implications for further dust storm research.

Cesium Radioisotopes↗
PubMed2001

Exposure assessment to airborne endotoxin, dust, ammonia, hydrogen sulfide and carbon dioxide in open style swine houses.

Information is limited for the exposure levels of airborne hazardous substances in swine feed buildings that are not completely enclosed. Open-style breeding, growing and finishing swine houses in six farms in subtropical Taiwan were studied for the airborne concentrations of endotoxin, dust, ammonia, hydrogen sulfide and carbon dioxide. The air in the farrowing and nursery stalls as partially enclosed was also simultaneously evaluated. Three selected gases and airborne dusts were quantified respectively by using Drager diffusion tubes and a filter-weighing method. Endotoxin was analyzed by the Limulus amoebocyte lysate assay. Average concentration of airborne total endotoxin among piggeries was between 36.8 and 298 EU/m(3), while that for respirable endotoxin was 14.1-129 EU/m(3). Mean concentration of total dust was between 0.15 and 0.34 mg/m(3), with average level of respirable dust of 0.14 mg/m(3). The respective concentrations of NH3, CO2 and H2S were less than 5 ppm, 600-895 ppm and less than 0.2 ppm. Airborne concentrations of total dust and endotoxin in the nursery house were higher than in the other types of swine houses. The finishing house presented the highest exposure risk to NH3, CO2 and H2S. Employees working in the finishing stalls were also exposed to the highest airborne levels of respirable endotoxin and dust. On the other hand, the air of the breeding units was the least contaminated in terms of airborne endotoxin, dust, NH3, CO2 and H2S. The airborne concentrations of substances measured in the present study were all lower than most of published studies conducted in mainly enclosed swine buildings. Distinct characteristics, including maintaining swine houses in an open status and frequent spraying water inside the stalls, significantly reduce accumulation of gases and airborne particulates.

Air Pollution, Indoor↗
PubMed2001

Climate controls on dust storm occurrence in Maowusu Desert, Inner Mongolia, north China.

Dust storms occurring in arid and semi-arid regions play a main role in the evolution of landscapes. Climate is generally regarded to be important factors influencing the occurrence of dust storm, however, the way of climate controlling dust storms had been poorly understood. In this paper, we present the Ew Index model to describe the relationship between climate variables and dust storm frequency using the available meteorological data from three meteorological stations in Maowusu Desert. This index model explains 83.6%, 69.5% and 65.09% of the variance of dust storm frequency in three regions from the north to the south, respectively and this difference is probably caused by the difference of the human disturbance. The Ew Index model is an effective predictor of dust storm frequency and provides us a quite good understanding on the occurrence of dust storms in Maowusu Desert.

China↗
PubMed2002

Reducing dust using the electrocautery pencil with suction combined with the infusion catheter in mastectomy.

The dust from the vaporized tissue released during a mastectomy presents a hazard to the patients and the operating room personnel. More dust has been noted using the conventional electrocautery pencil in dissecting breast tissue than with the metal knife used in the past. It is very important to reduce the hazardous dust released during mastectomy. For this study 80 patients undergoing mastectomy for breast cancer from March to June 2001 were divided into two groups: 1) those whose dissections were performed with a combination of an electrocautery pencil and suction with an intravenous infusion catheter (40 cases) and 2) those whose dissections were performed with the conventional method in which the electrocautery pencil was handled by the surgeon and the metal suction tube was used separately by an assistant (40 cases). During mastectomy the personal air sampler was affixed to the operator's neck to collect the dust from the vaporized tissue. The concentrations of the total dust were significantly lower in the combined electrocautery-suction method (mean 5.56 +/- 3.26 microg/m3) than in the conventional method (mean 34.81 +/- 4.83 microg/m3) during mastectomy (P < 0.05). Although the operating time and blood loss were less in the combined method than in the conventional method this difference was not statistically significant (P > 0.05). The combined method of using the electrocautery pencil for dissecting breast tissue along with the intravenous infusion catheter reduced the concentrations of the total dust from the vaporized tissue plume. Furthermore this method reduces the hazards of dust to the surgeons and operating room personnel. Additionally the cost of this combined method is lower than that of the conventional method.

Adult↗
PubMed1992

Quantitative risk assessment for lung cancer from exposure to metal ore dust.

To quantitatively assess risk for lung cancer of metal miners, a historical cohort study was conducted. The cohort consisted of 1113 miners who were employed to underground work for at least 12 months between January 1, 1960 and December 12, 1974. According to the records of dust concentration, a cumulative dust dose of each miner in the cohort was estimated. There were 162 deaths in total and 45 deaths from lung cancer with a SMR of 2184. The SMR for lung cancer increased from 1019 for those with cumulative dust dose of less than 500 mg-year to 2469 for those with the dose of greater than 4500 mg-year. Furthermore, the risk in the highest category of combined cumulative dust dose and cigarette smoking was 46-fold greater than the lowest category of dust dose and smoking. This study showed that there was an exposure-response relationship between metal ore dust and lung cancer, and an interaction of lung cancer between smoking and metal ore dust exposure.

Adult↗
PubMed2002

[Quantitative experimental study of pneumoconiotic changes in the lungs by dusts containing free silica].

OBJECTIVE: To explore the integrative quantitative index of the extent of pneumoconiotic changes by dusts and to evaluate the extent of pulmonary injury by the dusts containing different contents of free silica. METHODS: In accordance with the morphometric principle, the areas of each kind of pathologic changes in the lung tissue sections of pneumoconiosis model were measured by utilizing a computer-aided graphic analyzer, and the volume density of each pathologic change and the value of pulmonary injury by dust(VPID) were calculated. Meanwhile the extent of pulmonary injury were compared among the rat groups treated with the dusts containing different contents of free silica. RESULTS: There were significant differences among each groups in the volume density of some pathologic changes in the same exposed periods. There were significant correlation between VPID and the content of free silica dust or the lung collagen content (r = 0.535-0.849, P < 0.005 or P < 0.01). Furthermore, the degree of cor relationship of VPID with both of the latter were higher than the sum of unweighted volume density of the various pathologic changes in lung. CONCLUSION: It is suitable, reasonable and simple to use VPID an index to indicate the extent of pulmonary injury by dust and to diagnose pneumoconiosis in pathology, and the extent of pulmonary injury by dust may be aggravated with the increasing of the content of free silica.

Animals↗
PubMed2003

[Morphological transformation of mouse NIH3T3 cells induced by nickel refining dusts in vitro].

OBJECTIVE: To study the biological effects of nickel-refining dust. METHODS: The cell phagocytosis, transformation activity, and cytotoxicity of the mouse NIH3T3 cells treated with nickel-refining dusts from two nickel-refining factories in China were observed, and the risk of carcinogenicity was studied. RESULTS: (1) Two samples of nickel-refining dusts could be phagocytosed by mouse NIH3T3 cells with different phagocytizing rates of 69.0% and 39.0% at 100.000 micro g/ml, and 78.0% and 47.0% at 200.000 micro g/ml respectively. The relative clone formation rates at 12.500 micro g/ml to 100.000 micro g/ml were 71.1% to 3.9% and 84.4% to 9.1%, respectively. The cytotoxicity expressed by clone formation rate was similar to that of Ni(2)O(3), but higher than that of TiO(2) and lower than the positive control of N-methyl-N'-nitro-N-nitroso-guanidine (MNNG). (2) MNNG, Ni(2)O(3) and the two samples of nickel-refining dusts could induce morphological transformation in NIH3T3 cells. The transformation rate at 12.500 micro g/ml to 50.000 micro g/ml were 1.9% to 3.6% and 0.9% to 2.5% respectively in a dose-dependent manner. (3) The NIH3T3 cells treated by MNNG and nickel-refining dusts could induce Con A agglutination, and may form as clone in soft agar. This finding proved the reliability of the transformed clone. CONCLUSIONS: The present study for the first time demonstrate that nickel-refining dusts have cell transformation activity. The findings provide a new experimental evidence for the carcinogenic risk of nickel-refining dusts, and for the aetiology of lung cancer in nickel-refining workers.

Animals↗
PubMed2004

House dust mite allergen (Derp1 and Blot5) levels in asthmatics' home in Hongkong.

OBJECTIVE: To measure Derp1 and Blot5 allergen levels in asthmatics' homes in Hongkong. METHODS: Seventy houses were enrolled for a mite indoor environment study. Dust samples were obtained from two sites of each patients' house: bed and floor. Derp1 and Blot5 levels were quantified by a two-site monoclonal antibody-based ELISA technique. RESULTS: The levels of Derp1 allergens found in bed (geometric mean (GM) 3.43 microg/g of dust; 95%CI, 1.89-4.96 microg/g) and on the floor (GM 1.12 microg/g of dust; 95%CI, 0.71-1.53 microg/g) indicated significant differences (P=0.005). However, the levels of Blot5 allergens found in bed (GM 19.00 microg/g of dust; 95%CI, 0.89-38.90 microg/g) and on the floor (GM 6.14 microg/g of dust; 95%CI, 0.40-11.90 microg/g) showed no statistically significant difference. In addition, in regards to the exposure index for Derp1 and Blot5 allergens found in bed and on the floor, 17.6% in bed and 8.6% on the floor had levels of Blot5 > or = 10 microg/g of dust, higher than those obtained for Derp1 (7.2% and 0% in bed and on the floor respectively, P<0.05); higher percentages in bed and on the floor (25.0% and 35.7%) were observed for levels of Blot5 = 0 microg/g of dust as compared with Derp1 in bed and on the floor (4.3% and 14.5% respectively, P<0.05). CONCLUSIONS: Derp1 and Blot5 are the major allergens found in this regional study, Blot5 is a more potent allergen in Hongkong, probably reflecting the high level of exposure to Blomia tropicalis (Bt). Bt and Dermatophagoides pteronyssinus (Dp) allergens should be included for precise diagnosis and effective immuno-therapeutic treatment of mite allergy in Hongkong.

Allergens↗
PubMed2004

Ochratoxin A in grain dust--estimated exposure and relations to agricultural practices in grain production.

Ochratoxin A (OTA) is a nephrotoxin frequently contaminating grains. OTA inhalation during grain handling may therefore represent a health risk to farmers, and was the subject of this study. Airborne and settled grain dust was collected during grain work on 84 Norwegian farms. Climate and agricultural practices on each farm were registered. Penicillium spp., Aspergillus spp. and OTA in settled dust were measured. Settled dust contained median 4 microg OTA/kg dust (range 2-128), correlating with Penicillium spp. (median 40 cfu/mg; range 0-32000, rs =0.33; p < 0.01). Similar levels were found across grain species, districts and agricultural practices. Penicillium levels, but not OTA levels, were higher in storage than in threshing dust (p=0.003), and increased with storage time (rs =0.51, p < 0.001). Farmers were exposed to median 1 mg/m3 (range 0.2-15) dust during threshing and median 7 mg/m3 (range 1-110) dust during storage work, equalling median 3.7 pg/m3 (range 0.6-200) and median 40 pg/m3 (range 2-14000) OTA, respectively (p < 0.001). Agricultural practices could not predict OTA, Penicillium or Aspergillus contamination. Compared to oral intake of OTA, the inhalant exposure during grain work was low, although varying by more than 1,000-fold. However, the farmers may occasionally be highly exposed, particularly during handling of stored grain.

Carcinogens↗
PubMed2005

Respiratory effects of exposure to dust from herbs.

A group of 150 people occupationally exposed to dust from herbs were examined. As a reference group, 50 urban dwellers, not exposed to any kind of organic dust were examined. People were subjected to routine physical examination and to lung function examinations with the LUNGTEST 500 spirometer (MES, Kraków, Poland). The spirometric values of the forced expiratory volume in one second (FEV (1)), vital capacity (VC) and FEV(1)/VC were recorded before and after work. Physical chest examination revealed pathological crepitations in 10 people (6.7 %). The mean baseline spirometric values in the study and reference groups did not show significant differences compared to the normal values. In the herb workers exposed to organic dust the post-shift decrease of all analysed spirometric values was noted. The post-shift decrease of some spirometric values (VC, VC % of normal values) was highly significant (p < 0.01). There was evidenced of a significant positive correlation between the age of examined people and decrease of VC and FEV(1) values. In 12 exposed workers the decrease of FEV(1) or FEV(1) % of normal values higher than 15 % was noted. 50 % of these workers cultivated thyme (Thymus vulgaris L.). This may suggest that dust from herbs, especially thyme dust, may cause acute airway obstruction. In the group showing significant decrease of FEV(1)/FEV(1) % of normal values ( > 15 %) the frequency of reported respiratory work-related symptoms (83.3 %) was higher than in the rest of exposed group (61.5 %). In conclusion, occupational exposure to dust from herbs may cause harmful effects on the respiratory system among herb processing workers. This indicates the need for use of prophylactic measures in this professional group, the more so as number of people occupationally exposed to dust from herbs is growing.

Adolescent↗
PubMed2005

Wood dust exposure in wood industry and forestry.

The aim of the study was to determine occupational exposure in Croatian wood processing industry and forest workers to harmful effects of wood dust on the risk of nose, nasal cavity and lung carcinoma. Mass concentrations of respirable particles and total wood dust were measured at two wood processing plants, three woodwork shops, and one lumbering site, where 225 total wood dust samples and 221 respirable particle samples were collected. Wood dust mass concentration was determined by the gravimetric method. Mass concentrations exceeding total wood dust maximal allowed concentration (MAC, 3 mg/m3) were measured for beechwood and oakwood dust in 38% (79/206) of study samples from wood processing facilities (plants and woodwork shops). Mass concentrations of respirable particles exceeding MAC (1 mg/m3) were recorded in 24% (48/202) of samples from wood processing facilities (mean 2.38 +/- 2.08 mg/m3 in plants and 3.6 +/- 2.22 mg/m3 in woodwork shops). Thus, 13% (27/206) of work sites in wood processing facilities failed to meet health criteria according to European guidelines. Launching of measures to reduce wood dust emission to the work area is recommended.

Croatia↗
PubMedDate not supplied

[Relation between Der p2 and Der f2 antigen levels in house dust and the degree of sensitization in asthmatic patients].

BACKGROUND: The continuous exposure to high levels of environmental allergens, as dust mite, gets worse the reactivity of the airways as mentioned in previous studies. In other international studies, it has been determined the levels of house dust mite antigen needed to sensitize asthmatic patients, but few studies in Mexico have measured the concentration of house dust mite antigen before the initial treatment and correlated the sensitization to it with the levels of total IgE and the skin test. OBJECTIVE: To determine the minimum concentration of house dust mite antigen required to sensitize patients with asthma at the Distrito Federal and if it exists a correlation between the different concentration of the antigen, the results of the skin test and the total IgE. MATERIAL AND METHODS: Thirty patients with asthma and positive skin test to Dermatophagoides pteronyssinus took part in the study. We made a home visit to measure the concentration of Der p2 and Der f2 in house dust and we scheduled a visit at our hospital to measure the IgE total level. We did a statistical analysis with the chi square test and the correlation coefficient of Pearson and we found that the lower level needed to sensitize was 0.2 micrograms of antigen per gram of house dust. It did not exist a correlation between the total IgE levels and the concentration of the mite antigen. CONCLUSION: To a higher level of the house dust mite antigen we found more sensitization to it, as shown by the skin test but without direct relation with the total IgE levels in patients with asthma.

Adolescent↗
PubMed2005

[Experimental study on the DNA damage of NIH/3T3 cells induced by nickel-refining dusts].

OBJECTIVE: To study the effects of nickel-refining dusts on DNA damage in mouse NIH/3T3 cell. METHOD: DNA damage of mouse NIH/3T3 cell induced by two nickel-refining dust samples was determined with single cell gel electrophoresis (SCGE) technique. RESULTS: (1) Under the condition of the same treatment time, the tailed cell (%) of NIH/3T3 cells increased with the increase in doses of nickel-refining dusts (35.5%, 69.7%, 85.2%, 41.3%, 75.7%, 89.2% respectively except for sample 2, 50 microg/ml, 24 h group), and DNA strand breaks reached the peak value at 4 h of exposure; (2) When we treated the NIH/3T3 cells with the same dose of nickel-refining dusts, the tail rate at 4 h was higher than those at 2 h and 24 h of exposure; (3) Both sample 1 and sample 2 with different doses of nickel-refining dusts could induce higher comet tail, DNA%, tail length (except for 12.5 microg/ml), extent of TM (except for sample 1, 12.5 microg/ml) than in control group (P < 0.05). The DNA damage range was significantly increased in different tested doses of nickel-refining dusts and the damage range reached the peak value when the cells were treated for 4 h. CONCLUSION: Nickel-refining dusts could induce different degree DNA damage in NIH/3T3 cells.

Animals↗
PubMedDate not supplied

Critical analysis of studies concerning reports of respiratory sensitization to certain wood dusts.

Studies have been published reporting that exposures to certain wood dusts are sensitizing, resulting in respiratory symptoms in susceptible individuals. Many of the publications in this field are case reports that collectively have a number of important shortcomings. Illuminating these should further our understanding of whether respiratory sensitization results from occupational exposure to particular wood dusts. The aim of this study was to critically review and understand the evidence to date regarding reported respiratory sensitization in connection with wood dusts from oak, beech, pine, ash, and western red cedar. Publications dealing with these commercially important woods in North America have been selected from the Pubmed/Medline database (1966 to the present) using the key word, wood dust. These articles, along with supporting references on procedures and techniques, are reviewed according to the strengths and weaknesses of evidence and conclusions presented. Evidence from skin testing, specific immunoglobulin E measurements, and basophil histamine release tests suggests that reported symptoms are not likely to be immunologically derived. Because of methodological problems, challenge tests with specific wood dusts do not support the conclusion that reactions to certain wood dusts are specific. Experiments with nonspecific bronchoconstrictive agents indicate that a number of study subjects possess hyperresponsive airways. Thus, select individuals can demonstrate various respiratory symptoms in the woodworking industry, but any specificity or direct cause is currently unproved. Current studies do not support that exposure to wood dusts from a number of common North American wood species causes immunologic sensitization in woodworkers. Rather, symptoms reported in some studies of exposed workers seem to follow the paradigm for nonspecific respiratory responses in individuals with hyperresponsive airways.

Allergens↗
PubMed2006

[The cytotoxicity of nickel-refining dusts for chinese hamster lung cells and effects on gap junctional intercellular communication].

OBJECTIVE: To investigate the cytotoxicity of the nickel-refining dusts for Chinese hamster lung (CHL) cells and the effects of nickel-refining dusts on the gap junctional intercellular communication (GJIC) of CHL cells. METHODS: The cytotoxicity of the nickel-refining dusts for the CHL cells was determined in two nickel-refining dusts samples with the CHL cells as the target cells by MTT method while the effects of nickel-refining dusts on the CJIC of the CHL cells were investigated using the scrape-loading and dye transfer (SLDT) technique. RESULTS: There were no significant difference in the CHL proliferation between all dosage groups in the two samples and the control group at 6 and 12 hours (P > 0.05). The survival rate of cells in all dosage groups were all decreased at 36 hours (P < 0.05), presenting the dosage-reaction relationship and the time-reaction relationship. IC(50) was 21.36 and 23.07 micro/ml for the two samples respectively at 36 hours. Compared with the control group, the transport of Lucifer Yellow (LY) from the injury line to the adjacent cells was decreased when the CHL cells were treated with nickel-refining dusts of 25.00, 50.00 and 100.00 microg/ml (P < 0.01). CONCLUSION: The nickel-refining dusts have cytotoxicity for the CHL cells cultivated in vitro, can inhibit the growth of the cells and at a certain concentration can inhibit the GJIC function of CHL cells.

Animals↗
PubMed2006

[Dust particles mainly containing silicon found in the cells of granulomas of sarcoidosis].

OBJECTIVE: To investigate if there are dust particles in the cells of granulomas of sarcoidosis and analyze its composition and the possible correlation between the sarcoidosis and the composition of dust particles. METHODS: The samples of 50 patients with sarcoidosis and 6 patients with silicosis as control were collected by biopsy and/or autopsy sampling. The pathological varieties of the granulomas and the situation of the dust particles within the cells of granulomas were observed using hematoxylin and eosin staining, Warthin-Starry silver staining, immunohistochemistry staining as well as the transmission electron microscope, and the X-Ray spectrum chemical element analysis in the samples from these two kinds of diseases. RESULTS: The dust particles containing silicon as the main chemical element were present in epithelioid cells and multinucleate giant cells in all the samples. The quantity of the particles deposited in sarcoidosis was less than that in the silicosis. Moreover, the dust cells were found in the granulomas and the visceral pleural lymphatic vessels in the pleura and the hilar pulmonary lymph nodes in sarcoidosis and silicosis. The pathological varieties of the granulomas in sarcoidosis and silicosis were similar. CONCLUSION: There are less silicon dust particles in the cells of granulomas of sarcoidosis than in those of the silicotic nodules, which indicates that the silicon dust particles may be related to the sarcoidosis.

Adolescent↗
PubMed1975

A cell kinetic study of the alveolar wall following dust deposition.

The stathmokinetic technique was used to study quantitatively the proliferative response of cells comprising the alveolar wall of inbred mice which had inhaled coal or quartz. The exposures occupied 4 weeks and the observations continued over an extended period thereafter. Control observations suggested that mitotic inhibition was induced solely by residence in the exposure chamber, since cessation of exposure was quickly followed by a temporary rise of proliferative activity. This feature was not apparent when dust was inhaled, though with comparable exposure to both coal and quartz there was an elevation in mitotoic incidence of alveolar wall cells in dust-free areas of lung at a later interval. In dust-laden areas the rise was less in evidence, a situation that persisted throughout the post-exposure survival. The difference in mitotic incidence between dust-free and dust-containing areas was more evident after coal than after quartz inhalation, whilst in higher concentration a quartz aerosol induced a continued depression of mitotic activity. The proliferative response seen in the alveolar walls of control and dusted mice is most likely to be contributed by the interstitial precursors of alveolar macrophages, cells which are recognized to be marrow derived. The changes observed in mitotic incidence are interpreted in terms of demand for alveolar macrophages according to the nature of the dust and the inintensity of the exposure.

Animals↗
PubMed1990

A comparative environmental and medical study of dust exposure in jute and cotton mills in Burma.

Jute is extensively cultivated and processed in Burma, as well as "lower-grade" cotton. This study was conducted there to compare dust exposure in jute and cotton mills, to study the acute and chronic effects of dust exposure on workers, and to establish exposure-response relationship. A sample of 799 male and female workers in two jute mills and two cotton textile mills, as well as a control group of 153 matching subjects, was examined, and dust exposure in the work environment was evaluated. Very high dust concentrations existed in the early stages of jute processing and sorting, which were reduced when jute fibers got cleaner, as in drawing and spinning, and were related to the grade of the processed fiber. Much lower concentrations of dust existed in the cotton mills, but exceeded the TLV (ACGIH) only in opening and cleaning and in carding operations. However, byssinosis occurred only in workers exposed to cotton dust, particularly among males, and its prevalence was related to the level and duration of dust exposure. Chronic bronchitis, cough and wheezing occurred at higher rates among all workers than in the control, while irritation to nose and throat, eyes and skin prevailed only among jute workers. A significant reduction in FVC, FEV1.0 and PEF (before and during shift) was observed in workers compared to control subjects, and was related to workers' exposure and age; however, this reduction was not related to symptoms of different respiratory conditions. "Cheroots" smoking was found to be an important potentiating factor in the occurrence of non-specific respiratory diseases and reduction in FEV1.0, particularly among jute workers.

Adult↗