OBJECTIVES: This study was designed to evaluate cytotoxicity of TAFMAG, which is a trade name of natural mineral fiber mined and produced in China. METHODS: The cytotoxicity of TAFMAG was evaluated by measuring iron content, lipid peroxidation, erythrocyte hemolysis, and cytotoxicity in vitro. These results were compared with the data of chrystotile and wollastonite as a positive and negative control, respectively. RESULTS: There was significant increase of Fenton activity in TAFMAG and chrysotile with dose-response pattern. The iron chelating agent, desferrioxamine, significantly decreased Fenton activity of the particulates except wollastonite. TAFMAG and chrysotile fibers significantly increased malondialdehyde concentration from lipid peroxidation of the red blood cell membrane. In erythrocyte hemolysis test, TAFMAG & chrysotile had stronger effect on erythrocyte hemolysis than wollastonite with the concentration of 1,000g/ml. Furthermore, TAFMAG was more hemolytic than chrysotile with the concentration of 5.000 g/ml. There was a significant cytotoxic effect in TAFMAG and chrysotile on RAW cell compared with wollastonite. CONCLUSIONS: In vitro study suggested that TAFMAG may have a similar health hazard as usual asbestos.
Asbestos ; Asbestos, Serpentine ; China ; Deferoxamine ; Erythrocytes ; Hemolysis ; Iron ; Lipid Peroxidation ; Malondialdehyde ; Membranes ; Mineral Fibers

OBJECTIVES: Asbestos is a carcinogenic mineral substance formerly used widely in the construction industry, all forms of which, except for chrysotile asbestos, have been banned in the Philippines. This article aims to propose policy alternatives to reduce the health and economic effects of continued asbestos use in the country.
METHODS: Records of asbestos-related diseases, and asbestos industry-related data in the country were consolidated. The impact of continued asbestos use on the national economy were estimated incorporating natural mortality, regulations of the Department of Labor and Employment (DOLE), and concepts of multiplier effect and net present value. Round table discussions validated data and generated policy recommendations.
RESULTS: Filipinos directly and indirectly exposed to asbestos-containing materials (ACMs) are 5,289 and 30,000, respectively. The contributions of these groups to the national economy were estimated at PhP 1.08 Billion annually for workers directly exposed to ACMs and PhP 6.83 Billion annually for workers indirectly exposed. Two policy options--adjustment of threshold limit values, and a total ban--are presented.
CONCLUSION: A total ban on all forms of asbestos is shown to be the more cost-effective policy option for the country. It is recommended that government agencies, stakeholders in the asbestos industry, and the general public be involved in strategies for improving surveillance on asbestos exposure, increasing public awareness, and promoting the use of asbestos alternatives.

Asbestos, Serpentine ; Threshold Limit Values ; Construction Industry ; Philippines ; Asbestos ; Carcinogens ; Policy ; Government Agencies ; Employment

OBJECTIVETo clarify the dose-response relationship between asbestos dust exposure and lung cancer incidence in chrysotile asbestos miners by fixed cohort study and to investigate the incidence rates of lung cancer in exposure to different concentrations of asbestos dust.

METHODSA retrospective cohort study was conducted in 1932 asbestos miners who registered from January 1, 1981 to December 31, 1988, had worked for at least 1 year, and had no obvious cardiopulmonary diseases; the cohort study began in July 2009 and covered a time span of 29 years (1981 - 2009). The personal information, occupational history, disease history, and health data of these miners were recorded, and the monitoring data on dust concentrations in the mine over the years were collected. The dose-response relationship between asbestos dust concentration and lung cancer incidence was established by the method of life table; a regression equation was fitted to predict the excess incidence rates of lung cancer under the conditions of different working years and dust concentrations.

RESULTSA significant dose-response relationship was observed between cumulative exposure (Ce) and cumulative probability (Px) of lung cancer incidence, and the smokers hada higher Px than nonsmokers. When Ce was less than 2000 mg/m(3)·each year, Px reached 6.58/10000; when Ce was not less than 2000 mg/m(3)·and less than 3000 mg/m(3)·each year, Px reached 91.72/10000; when Ce was more than 5000 mg/m(3)·each year, Px was as high as 141.02/10000. The three models were fitted to obtain the optimal regression equation: Px = -0.0004Ce(2) + 0.0052Ce - 0.0011 (r(2) = 0.9387). In the workshop of asbestos mine in this study, the average dust concentration was 85 times higher than the limit in 2009, so the excess incidence rate of lung cancer was 112.598/10000 if the miners worked under this condition for 40 years, according to the equation.

CONCLUSIONThere is a significant dose-response relationship between cumulative asbestos exposure and lung cancer incidence in chrysotile asbestos miners. The risk for lung cancer rises as asbestos exposure increases.

Asbestos, Serpentine ; toxicity ; Dust ; Female ; Humans ; Lung Neoplasms ; etiology ; Male ; Mining ; Occupational Exposure ; Retrospective Studies

OBJECTIVETo study the effects of aluminum citrate (AC), rare earth compounds (REC) and sodium selenite (SS) on the surface elements of chrysotile fibers and the inhibitory mechanisms of three compounds for chrysotile-induced biological activities.

METHODSAfter being soaked in 250, 500 and 1000 microg/ml aluminum citrate solutions, 125, 250, 500 and 1000 microg/ml mixed rare earths solutions or 125, 250, 500 and 1000 microg/ml sodium selenite solutions for 10 min or 1 hour, the fabrication and the levels of surface elements of chrysotile fibers were determined.

RESULTSAluminum citrate, mixed rare earths or sodium selenite all could be adsorbed by chrysotile fibers. After pretreatment of chrysotile fibers with aluminum citrate, mixed rare earths or sodium selenite solutions for 10 min or 1 hour, the corresponding elements or ion on the surface of chrysotile fibers increased with the increase of concentration of the solutions.

CONCLUSIONPretreatment of chrysotile with aluminum citrate, mixed rare earths or sodium selenite solutions can change the fabrication and the levels of surface elements of chrysotile fibers, and inhibit the biological activities of chrysotile by "sealing" some "active sites" on the surface of chrysotile fibers.

Asbestos, Serpentine ; chemistry ; toxicity ; Citric Acid ; chemistry ; Metals, Rare Earth ; chemistry ; Sodium Selenite ; chemistry

OBJECTIVETo analyze asbestos exposure level between 1984 and 2010 in a district of malignant mesothelioma with clustering incidence in Zhejiang Province, in order to improve the recognizing and early diagnosis of malignant mesothelioma, protect the health of workers.

METHODSMonitoring data of total asbestos dust concentration in the air of workplace from 1984 to 2010 in asbestos textile enterprises, family hand spinning operation, brake production, and asbestos board production in Zhejiang Province were collected in the local CDC. A total of 766 TWA copies of mass concentration were collected, and 1233 copies of MAC data. Asbestos mass concentration and fibre counting concentration of 29 points of family hand spinning operation were parallel determinated in the same time and the same sampling point. Raw asesbtos materials and dust composition of local asbestos processing corporations were collected and analyzed using X-ray diffraction method.

RESULTSRaw materials of asbestos used between 1984 and 2010 in this area were chrysotile from Sichuan, Qinghai, Xinjiang, Russia, Zimbabwe, and some were mixed with SiO2, CaCO3 and other impurities. Raw materials used in asbestos board production were blue asbestos. Dust concentration between 1960s and 1980s in asbestos processing plants far exceeded the national standard. After then the dust concentration decreased significantly, but still higher than the national standard. 95.2% of air dust concentrations in the workplaces of asbestos factories exceeded the standard, and dust concentrations of workplaces of raw material, spinning, weaving, carding and labor insurance were above 90% in which carding work had the highest median concentration. 37.9% of dust mass concentrations in hand spinning work exceeded the standard where textile machinery side had the highest value. Beating job in asbestos board manufacturing and grinding job in brake production had higher concentrations.

CONCLUSIONSMost of production technologies in asbestos processing industry exceed the standard level, indicating that the workers were at risk for malignant mesothelioma and other asbestos related diseases, which should draw high attention.

Asbestos ; analysis ; Asbestos, Crocidolite ; analysis ; Asbestos, Serpentine ; analysis ; China ; epidemiology ; Dust ; analysis ; Humans ; Lung Neoplasms ; epidemiology ; Mesothelioma ; epidemiology ; Occupational Diseases ; epidemiology ; Silicon Dioxide ; analysis ; Workplace

Asbestosis is a chronic inflammatory disorder of lower respiratory tract in which alveolar wall are progressively thickened by a fibrotic process. Fibrotic process characterized by an expansion of fibroblast and collagenous extracellular matrix secreted from this fibroblast. Alveolar macrophage is believed to be a primary target cell and major participant in the evolution of lung fibrosis after asbestos inhalation. Alveolar macrophage are known to release a variety of substance that induce tissue damage and stimulate inflammatory cells and fibroblast. Macrophage also release a variety of metabolite of arachidonic acid. Of these, PGE(2) is known to suppress fibroblast proliferation. Asbestos may be a very effective stimulus for fibroblasts without triggering the relase of PGE(2). To assess the fibrogenic properties of asbestos according to kind and dosage of asbestos and the ability of PGE(2) to suppress the proliferation of fibroblast, alveolar macrophages cultured with crocidolite, amosite and chrysotile in presence or absence of PGE(2)10(-5)M. At 24 hours after alveolar macrophage cultured with various stimuli, the released fibronectin and TNF-alpha was measured. Viability of alveolar macrophages was observed and growth promoting activity of macrphage supernatant to fibroblasts was quantified. The results were as follows; 1. The viability of alveoair macrophages stimulated with asbestos fiber was markedly decreased compared with control group except chrysotile 10 microgram group. Crocidolite and amosite were more cytotoxic than chrysotile. 2. All of asbestos augmented fibronectin production in concentration dependent fashion. 3. There was a significant positive correlation between TNF-alpha production in supernatant and fiber concentration. 4. Supernatant from alveolar macrophages cultured with asbestos were inducible a significant increase in fibroblast proliferation. 5. Incubation of avieolar macrophages with asbestos in the presence of PGE(2) resulted in significant decrease of TNF-alpha production in supernant. 6. Supernatant from alveolar macrophages cultured with asbestos were inducible a: sig nificnat decrease in fibroblast proliferation when PGE(2) was added. The result of this study strongly suggested that crocidolite and amosite were more cytotoxic and fibrogenic and exogenous PGE(2) suppressed fibroblast proliferation following exposed to asbestos.
Animals ; Arachidonic Acid ; Asbestos* ; Asbestos, Amosite ; Asbestos, Crocidolite ; Asbestos, Serpentine ; Asbestosis ; Collagen ; Extracellular Matrix ; Fibroblasts* ; Fibronectins ; Fibrosis ; Inhalation ; Lung ; Macrophages ; Macrophages, Alveolar ; Rats* ; Respiratory System ; Tumor Necrosis Factor-alpha

Asbestos is a fibrous silicate that was widely used because of its heat resistance properties. Asbestos exposure affects workers involved in mining or processing asbestos or those involved in the use of asbestos in the shipbuilding, construction, and textile- and insulation-manufacturing industries. There are three commonly available types of asbestos; chrysotile (white asbestos), amosite (brown asbestos), and crocidolite (blue asbestos). All three have been associated with cancerous and non-cancerous lung disease. Asbestos-related diseases includes benign pleural effusion, pleural plaques, diffuse pleural thickening (a non-malignant disease affecting the lung lining), rounded atelectasis, asbestosis (a scarring of the lung tissue caused by asbestos), mesothelioma and lung cancer. Mesothelioma is a malignant pleural or peritoneal tumor that rarely occurs in patients who have not been exposed to asbestos. The latency period of most asbestos-related disease is 10 years or longer, asbestos-related disease remains an important public health issue. The clinical diagnosis of asbestos related diseases should be based on a detailed interview of the patient and occupational data on asbestos exposure, signs and symptoms, radiological and lung physiological findings and selected cytological, histological and other laboratory studies. Radiological imaging plays a pivotal role in the diagnosis and management of asbestos-related disease.
Asbestos ; Asbestos, Amosite ; Asbestos, Crocidolite ; Asbestos, Serpentine ; Asbestosis ; Cicatrix ; Compensation and Redress ; Hot Temperature ; Humans ; Latency Period (Psychology) ; Lung ; Lung Diseases ; Lung Neoplasms ; Mesothelioma ; Mining ; Pleural Effusion ; Public Health ; Pulmonary Atelectasis ; Silicates ; Workers' Compensation

OBJECTIVETo determine there was excessive risk of malignant tumors or not among workers exposure to chrysotile fiber alone by applying a meta-analysis technique.

METHODSAll data meeting the criteria of cohort studies on cancer mortality among workers exposed only to chrysotile would incorporate into the meta-analysis. The pooled standardized mortality ratios (SMR) and their corresponding 95% confidence intervals (95% CI) for main cancer sites were calculated using two approaches of unweighted ratio and random effects model. The heterogeneity and its sources of the results were examined with a Q-statistic and Z-score test.

RESULTS26 chrysotile-exposed alone cohorts were summarized. The significantly elevated meta-SMRs for all deaths (1.28), all cancers (1.26), cancers of respiratory organs (2.24), cancer of lung (2.29) and cancer of stomach (1.27) were observed. The significantly elevated meta-SMRs for lung cancer within occupational strata were observed among textile workers (3.64), asbestos products manufacturers (3.07), miners and millers (2.24), cement products workers (1.22), and for stomach cancer among asbestos products manufacturers (1.48). Meta-SMRs for cancers at other sites were not significant.

CONCLUSIONThere were excessive risks of lung cancer and mesothelioma among workers exposure to chrysotile fiber alone, and likely no convincing indication of an etiological association between chrysotile exposure and cancers at other sites.

Asbestos ; poisoning ; Asbestos, Serpentine ; poisoning ; Cohort Studies ; Humans ; Neoplasms ; etiology ; mortality ; Occupational Exposure ; adverse effects ; Respiratory Tract Neoplasms ; etiology ; Survival Rate

OBJECTIVES: To obtain reference values for the pulmonary asbestos and non-asbestos fiber contents of residents in Korea and to compare them with similar results from Japan. METHODS: The autopsied lung specimens from 22 deceased people (20 males and 2 females) in Pohang, without any known occupational history of asbestos exposure, were analyzed for incidence of asbestos and non-asbestos fibers by transmission electron microscopy with energy dispersive X-ray analysis after using low temperature ashing procedures. RESULTS: Chrysotile fiber (46.2%) was the major fiber type found in the lungs of the subjects. The asbestos fiber concentrations found in males and females were 0.09x106 fibers/(g of dry lungs) and 0.30x106 fibers/(g of dry lungs), respectively, showing a geometric mean concentration 0.09x106 fibers/(g of dry lung tissue), due to the predominance of males in the sample. The non-asbestos fiber contents in males and females were 4.61x106 fibers/(g of dry lungs) and 17.79x106 fibers/(g of dry lungs), respectively, with a geometric mean concentration 5.21x106 fibers/(g of dry lung tissue). CONCLUSIONS: Residents in Pohang had significantly lower levels of both asbestos and non-asbestos fibers than urban residents in Korea. Furthermore, Koreans had significantly lower levels of both asbestos and non-asbestos fibers than Japanese.
Asbestos* ; Asbestos, Serpentine ; Asian Continental Ancestry Group ; Female ; Gyeongsangbuk-do* ; Humans ; Incidence ; Japan ; Korea ; Lung* ; Male ; Microscopy, Electron, Transmission ; Reference Values

OBJECTIVETo investigate the apoptosis rate and the reactive oxygen species (ROS) level induced by chrysotile fibers in BEAS-2B cells and the blockage effect of free radical scavengers on the induction of chrysotile fibers.

METHODSThe cell survival rate, the morphological variation of BEAS-2B cells, the apoptosis rate, the expression levels of gene caspase-3 and the ROS generation level were measured by using trypan blue phagocytosis, hematoxylin and eosin staining, oligonucleosomal DNA fragmentation assay, FCM, RT-PCR and fluorescent probe DCFH-DA in the suspension (0, 5, 10, 20, 100 and 200 microg/cm(2)) and the filtrate (0, 100, 200, 400, 800 and 1600 microg/ml) of chrysotile fibers. Addition of free radical scavengers such as catalase, dimethyl sulfoxide and mannitol prevented the radical generation and gene expression.

RESULTSSurvival rates of BEAS2B cells treated by the suspension (0, 5 and 10 microg/cm(2)) and the filtrate (0, 100 and 200 microg/ml) of chrysotile fibers for 24 hours were above 90%. The apoptotic rates of BEAS-2B were increased with the concentration of suspension and filtrate from chrysotile fibers (P < 0.05). Otherwise, caspase-3 mRNA and ROS were stimulated by chrysotile fibers. Free radical scavengers such as CAT, DMSO and mannitol could reduce these stimulations. The ROS blocking rate of suspension of chrysotile fibers was 23.7%, 21.6% and 11.2% respectively, and that of filtrate was 37.9%, 40.3% and 10.6% respectively.

CONCLUSIONApoptosis is induced in BEAS-2B cells exposed to chrysotile fibers suspension and filtrate. Generation of ROS plays an important role in chrysotile fibers-induced BEAS-2B cell apoptosis.

Apoptosis ; drug effects ; Asbestos, Serpentine ; toxicity ; Cell Line ; Drug Antagonism ; Epithelial Cells ; drug effects ; metabolism ; pathology ; Free Radical Scavengers ; pharmacology ; Humans ; Oxidative Stress ; Reactive Oxygen Species ; metabolism