tremolite and Asbestosis

A 51-year-old man underwent pleuroscopy for radiologic pleural abnormalities. Pathologic examination of pleural and lung biopsy specimens concluded on hyalinized pleural plaques associated with mild asbestosis. Transmission electron microscopy analysis showed significant retention of tremolite asbestos fibers. The absence of any occupational exposure to asbestos and the existence of geologic deposits of tremolite in the Kabul area of Afghanistan suggest an environmental exposure during the patient's childhood spent in this region.

Topics: Afghanistan; Air Pollutants; Asbestos, Amphibole; Asbestosis; Biopsy; Environmental Exposure; Humans; Lung; Male; Middle Aged; Pleura; Pleural Diseases

Tissues obtained at autopsy or biopsy from 81 workers and 2 household persons, were chemically digested. The asbestos fibres recovered were characterized by analytical transmission electron microscopy. Among the 83 causes of death were 33 mesotheliomas, 35 lung cancers, 12 asbestosis and 3 from other cancers. Of the three major commercial asbestos fibre types, amosite was found to be the most prevalent fibre, occurring in approximately 76% of the cases, followed by chrysotile in approximately 60% and crocidolite in approximately 24%. Amosite and chrysotile were observed as the single commercial fibre in approximately 22 and approximately 17% of the cases respectively, whereas crocidolite and tremolite were found as the single fibre type in only approximately 2.5% of the cases. Among the fifteen cases where chrysotile and tremolite occurred together, the amount of chrysotile fibre always exceeded tremolite. However, tremolite was also found in ten additional cases where chrysotile was not detected. Amosite was present in four, amosite plus crocidolite in three, and crocidolite alone in one. Amosite was present in all of the insulation workers' lungs studied and was found in the highest concentration in this exposure category. The highest chrysotile concentration was found among workers in general trades. Although most prevalent in shipyard workers lungs, crocidolite concentration is not statistically different among the exposure groups studied. Although crocidolite was found in twenty cases, amosite accompanied it in eighteen of these. Eleven of the 20 cases were from shipyard workers. Of the 8 mesothelioma cases, 7 also contained amosite. Crocidolite alone only occurred in 1 of the 33 mesothelioma cases analysed. We concluded the following: crocidolite exposure occurred among USA insulators and a large percentage of other workers as well; insulation workers are primarily exposed to amosite; mixed fibre exposures are associated with more mesotheliomas than single fibre exposures; chrysotile only exposure is associated with approximately 12% of the mesothelioma cases studied; and if tremolite exposure is associated with chrysotile exposure, the chrysotile amount exceeds that for the associated tremolite.

Topics: Aged; Asbestos; Asbestos, Amosite; Asbestos, Amphibole; Asbestos, Crocidolite; Asbestos, Serpentine; Asbestosis; Autopsy; Biopsy; Female; Humans; Lung; Lung Neoplasms; Male; Microscopy, Electron; Middle Aged; Occupational Exposure; Organ Culture Techniques; United States

Worldwide studies have been published on the mortality of workers employed in asbestos-based materials for the production of clutches and brakes. However no one of these studies is related to Italian cases. Furthermore, not even surveys have been conducted in Italy to characterize the correlation between asbestos exposures and the possible occurring of asbestos-related disease. Our objectives are the following: i) to assess and quantify the asbestos exposure cases, ii) to describe the nature and the frequency of asbestos-related diseases among blue collar employees of an important factory producing brakes and clutches with chrysotile asbestos content from 1971 to 1993 and iii) to provide preliminary data on cumulative asbestos exposure estimated using lung fibre burden analysis. Critical appraisal of airborne asbestos fibre measurements and identification of cases of asbestos-related diseases between the blue collar employees, either notified to the local health authority or recovered from the Italian national Mesothelioma registry was investigated. Lung fibre burden analysis using the lung tissue samples from two deceased blue collar employees was also performed. Airborne asbestos fibre measurements (carried out in 1982) suggested asbestos fibres average concentrations of about 0.3 f/ml, while all 1992 measurements showed results below 0.1 f/ml. Furthermore, since 1988, we identified four cases of pleural plaques, three cases of asbestosis and seven cases of lung cancer. No case of malignant mesothelioma was found. In both lung cancer cases, analysed to measure the lung fibre burden, commercial amphiboles were absent or in limited concentration but chrysotile and, especially, tremolite asbestos were present in noticeable amount. In conclusion, since 1971 and up to early 1980s, exposure to chrysotile asbestos and talc, likely contaminated by tremolite, had been significant and comparable to levels causing asbestosis long-term risk. No case of malignant mesothelioma was found, that is consistent with the absence of amphiboles and with the lower risk of mesothelioma associated with the chrysotile asbestos. However a subset of the blue collar employees, the ones employed later on, could still have not reached the full risk condition, and so being still at risk of developing malignant mesothelioma. In the two lung cancer cases studied, the lung fibre burden was essentially made of chrysotile and tremolite. Lastly, lung cancer occurrence in the population of b. Nella letteratura scientifica sono presenti studi epidemiologici di mortalità su coorti di lavoratori addetti alla produzione di materiali di attrito in amianto ma non in Italia, dove neppure sono disponibili indagini conoscitive per caratterizzare l’esposizione ad amianto e la possibile presenza di patologie asbesto-correlate. Per questa ragione si è ricostruita la natura e l’entità dell’esposizione ad amianto, la frequenza e la tipologia delle patologie asbesto-correlate in lavoratori di una importante industria di materiali di attrito in asbesto crisotilo utilizzato dal 1971 al 1993; si sono inoltre forniti iniziali elementi per una stima dell’esposizione cumulativa ad asbesto dei lavoratori attraverso l’analisi del carico polmonare di fibre di amianto. Si è operata una valutazione dei monitoraggi ambientali e una rilevazione dei casi di patologie asbesto-correlate diagnosticati tra lavoratori della fabbrica, oltre all’analisi di campioni di tessuto polmonare di due lavoratori per la determinazione del carico residuo di fibre di amianto. Monitoraggi ambientali eseguiti nel 1982 indicavano concentrazioni medie di 0,3 fibre/cc e nel 1992 inferiori a 0,1 fibre/cc per tutti i campioni. Dal 1988 sono stati osservati 4 casi di placche pleuriche, 3 casi di asbestosi, 7 casi di tumore polmonare, nessun caso di mesotelioma maligno. In ambedue i casi di tumore polmonare con analisi delle fibre di amianto gli anfiboli erano assenti o con valori modesti mentre per il crisotilo e soprattutto per la tremolite le concentrazioni rilevate erano consistenti. In conclusione, dagli anni ’70 ai primi anni ’80 l’esposizione ad amianto crisotilo e a talco, in parte contaminati da tremolite, è risultata consistente e compatibile con casi di asbestosi. Non sono stati osservati casi di mesotelioma maligno. Non essendo stati usati anfiboli questo può essere dovuto al più basso rischio di mesotelioma associato al crisotilo, ma parte dei lavoratori assunti in anni successivi potrebbero non essere ancora a pieno rischio. Il carico polmonare di fibre nei due casi di tumore polmonare è essenzialmente dato dal crisotilo e dalla tremolite. La frequenza di tumori polmonari incidenti in questa coorte è verosimilmente sottostimata; il rischio di questa neoplasia dovrebbe essere valutato attraverso uno studio della mortalità della coorte.

Topics: Aged; Air Pollutants, Occupational; Asbestos, Amphibole; Asbestos, Serpentine; Asbestosis; Automobiles; Female; Friction; Humans; Italy; Lung; Lung Neoplasms; Male; Manufacturing Industry; Mesothelioma; Middle Aged; Mineral Fibers; Occupational Exposure; Preliminary Data; Talc; Time Factors

Naturally occurring asbestos (NOA) fibers are found in geologic deposits that may be disturbed by mining, earthworks, or natural processes, resulting in adverse health risks to exposed individuals. The toxicities of Libby amphibole and NOA samples including Sumas Mountain chrysotile (SM), El Dorado tremolite (ED), and Ontario ferroactinolite cleavage fragments (ON) were compared in male Fischer 344 (F344) rats 15 mo after exposure. Rat-respirable fractions of LA and SM displayed greater mean lengths and aspect ratios than ED and ON. After a single intratracheal (IT) instillation (0.5 or 1.5 mg/rat), persistent changes in ventilatory parameters and a significant increase in lung resistance at baseline and after methacholine aerosol dosing were found only in rats exposed to 1.5 mg SM. High-dose ED significantly elevated bronchoalveolar lavage lactate dehydrogenase (LDH) activity and protein levels, while high-dose SM increased γ-glutamyl transferase and LDH activities. A moderate degree of lung interstitial fibrosis after exposure to 1.5 mg SM persisted 15 mo after exposure, unchanged from previous findings at 3 mo. LA induced mild fibrosis, while ED and ON produced minimal and no apparent fibrosis, respectively. Bronchioloalveolar carcinoma was observed 15 mo after exposure to LA or ED. Data demonstrated that SM, given by bolus IT dosing on an equivalent mass basis, induced greater pulmonary function deficits, airway hyperresponsiveness, and interstitial fibrosis than other NOA, although unlike LA and ED, no apparent evidence for carcinogenicity was found. All NOA samples except ON cleavage fragments produced some degree of long-term toxicity.

Topics: Airway Resistance; Animals; Asbestos; Asbestos, Amphibole; Asbestos, Serpentine; Asbestosis; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Bronchoconstrictor Agents; Carcinogens; gamma-Glutamyltransferase; Inhalation Exposure; Intubation, Intratracheal; L-Lactate Dehydrogenase; Male; Methacholine Chloride; Rats; Rats, Inbred F344; Respiratory Function Tests; Survival Analysis

Fibrous tremolite is a mineral species belonging to the amphibole group. It is present almost everywhere in the world as a natural contaminant of other minerals, like talc and vermiculite. It can be also found as a natural contaminant of the chrysotile form of asbestos. Tremolite asbestos exposures result in respiratory health consequences similar to the other forms of asbestos exposure, including lung cancer and mesothelioma. Although abundantly distributed on the earth's surface, tremolite is only rarely present in significant deposits and it has had little commercial use. Significant presence of amphibole asbestos fibers, characterized as tremolite, was identified in mineral powders coming from the milling of feldspar rocks extracted from a Sardinian mining site (Italy). This evidence raises several problems, in particular the prevention of carcinogenic risks for the workers. Feldspar is widespread all over the world and every year it is produced in large quantities and it is used for several productive processes in many manufacturing industries (over 21 million tons of feldspar mined and marketed every year). Until now the presence of tremolite asbestos in feldspar has not been described, nor has the possibility of such a health hazard for workers involved in mining, milling and handling of rocks from feldspar ores been appreciated. Therefore the need for a wider dissemination of knowledge of these problems among professionals, in particular mineralogists and industrial hygienists, must be emphasized. In fact both disciplines are necessary to plan appropriate environmental controls and adequate protections in order to achieve safe working conditions.

Topics: Aluminum Silicates; Asbestos; Asbestos, Amphibole; Asbestosis; Carcinogens; Humans; Italy; Mining; Occupational Diseases; Occupational Exposure; Potassium Compounds

Asbestosis is a chronic lung disease caused by inhalation of asbestos, a fibrous mineral. It is one of the most severe diseases resulting from environmental contamination. We found asbestosis in a female Japanese macaque over 25 years of age that died from senility. Clear needle-like crystals were deposited throughout the lung lobes, particularly in the perivascular areas. Asbestos bodies were observed in some of these crystals. Fibrosis without inflammation was observed in the periarterial and peribronchiolar regions. The crystals were identified as tremolite, and a total of 16,633,968 asbestos bodies and 465,334,411 tremolite fibers were observed in 1 g of dry lung tissue. No tumors or pleural adhesions were seen. This is the first report of spontaneous asbestosis in a nonhuman animal.

Topics: Animals; Asbestos, Amphibole; Asbestosis; Female; Macaca

Studies of the health effects of non-asbestiform asbestos minerals remain inconclusive. Nephrite is a type of non-asbestiform tremolite mineral. We assessed the risk for pulmonary fibrosis in workers who process nephrite.. A cross-sectional study that included 344 stone workers and their families was undertaken in Taiwan in 2010. The diagnostic criteria for pulmonary fibrosis included (1) radiographic fibrosis profusion of 1/1 or greater and (2) audible lung crackles confirmed by physician. The nephrite samples were analyzed using polarized light and transmission electron microscopy combined with selected-area electron diffraction and energy-dispersive x-ray spectroscopy.. After excluding 16 subjects with histories of tuberculosis or previous employment in metal casting and welding, as well as 23 family members who had not worked in the stone industry, we analyzed 305 subjects. Processing nephrite increased the risk for pulmonary fibrosis (odds ratio = 2.8 [95% confidence interval = 1.0-9.9] and unchanged after adjustment for age and smoking). Bulk sample analyses showed that the nephrite is a tremolite mineral composed of both asbestiform and non-asbestiform components. The cat's-eye nephrite had the highest asbestiform fibrous content, and the average length and aspect ratio of elongated mineral particles were the highest of all the nephrite types. Compared with workers processing other types of nephrite, workers processing cat's-eye nephrite had the highest risk for pulmonary fibrosis.. Processing non-asbestiform tremolite mineral may increase the risk for pulmonary fibrosis. Medical monitoring is warranted for workers with such exposure.

Topics: Adult; Air Pollutants, Occupational; Asbestos, Amphibole; Asbestosis; Cross-Sectional Studies; Extraction and Processing Industry; Female; Humans; Logistic Models; Male; Microscopy, Electron, Transmission; Middle Aged; Mineral Fibers; Minerals; Multivariate Analysis; Occupational Exposure; Proportional Hazards Models; Risk Factors; Spectrometry, X-Ray Emission; Surveys and Questionnaires; Taiwan

Asbestos is associated with South African diamond mines due to the nature of kimberlite and the location of the diamond mines in relation to asbestos deposits. Very little is known about the health risks in the diamond mining industry. The objective of this study was to explore the possibility of asbestos exposure during the process of diamond mining.. Scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis were used to identify asbestos fibres in the lungs of diamond mine workers who had an autopsy for compensation purposes and in the tailings and soils from three South African diamond mines located close to asbestos deposits. The asbestos lung fibre burdens were calculated. We also documented asbestos-related pathological findings in diamond mine workers at autopsy.. Tremolite-actinolite asbestos fibres were identified in the lungs of five men working on diamond mines. Tremolite-actinolite and/or chrysotile asbestos were present in the mine tailings of all three mines. Mesothelioma, asbestosis, and/or pleural plaques were diagnosed in six diamond mine workers at autopsy.. These findings indicate that diamond mine workers are at risk of asbestos exposure and, thus, of developing asbestos-related diseases. South Africa is a mineral-rich country and, when mining one commodity, it is likely that other minerals, including asbestos, will be accidentally mined. Even at low concentrations, asbestos has the potential to cause disease, and mining companies should be aware of the health risk of accidentally mining it. Recording of comprehensive work histories should be mandatory to enable the risk to be quantified in future studies.

Topics: Air Pollutants, Occupational; Asbestos; Asbestos, Amphibole; Asbestosis; Autopsy; Databases as Topic; Diamond; Environmental Monitoring; Epidemiological Monitoring; Female; Humans; Lung; Male; Mesothelioma; Mineral Fibers; Mining; Occupational Exposure; Pleura; Risk Assessment; Soil Pollutants; South Africa; Talc; Workers' Compensation

Mediterranean regions such as Greece, Turkey, Cyprus, Corsica and New Caledonia have experienced epidemics of malignant mesothelioma as a result of non-occupational, "domestic" exposure to tremolite asbestos and fibrous erionite. This exposure to tremolite asbestos and fibrous erionite is typified "domestic" due to its prevalence in regions with natural deposits of tremolite asbestos (or fibrous erionite) where the material from tremolite asbestos or fibrous erionite is used for domestic applications such as whitewashing. However, these exposures may be useful in examining the potential consequences of even small amounts of amphibole asbestos fibers in the ambient air. It can also elucidate the effects of fibers that behave like amphibole asbestos. However, this type of exposure is not useful for studying the potential effects of small amounts of asbestos in the ambient air of big cities due to the differing nature of the fiber types and modes of exposure between the regions.

Topics: Air Pollutants; Asbestos, Amphibole; Asbestosis; Calcinosis; Carcinogens, Environmental; Disease Outbreaks; Female; Humans; Male; Mediterranean Region; Mesothelioma; Mineral Fibers; Pleural Diseases; Zeolites

Vermiculite from the mine near Libby, Montana, is contaminated with tremolite asbestos and other amphibole fibers (winchite and richterite). Asbestos-contaminated Libby vermiculite was used in loose-fill attic insulation that remains in millions of homes in the United States, Canada, and other countries.. This report describes asbestos-related occupational respiratory disease mortality among workers who mined, milled, and processed the Libby vermiculite.. This historical cohort mortality study uses life table analysis methods to compare the age-adjusted mortality experience through 2001 of 1,672 Libby workers to that of white men in the U.S. population.. Libby workers were significantly more likely to die from asbestosis [standardized mortality ratio (SMR) = 165.8; 95% confidence interval (CI), 103.9-251.1], lung cancer (SMR = 1.7; 95% CI, 1.4-2.1), cancer of the pleura (SMR = 23.3; 95% CI, 6.3-59.5), and mesothelioma. Mortality from asbestosis and lung cancer increased with increasing duration and cumulative exposure to airborne tremolite asbestos and other amphibole fibers.. The observed dose-related increases in asbestosis and lung cancer mortality highlight the need for better understanding and control of exposures that may occur when homeowners or construction workers (including plumbers, cable installers, electricians, telephone repair personnel, and insulators) disturb loose-fill attic insulation made with asbestos-contaminated vermiculite from Libby, Montana.

Topics: Aged; Aluminum Silicates; Asbestos, Amphibole; Asbestosis; Cohort Studies; Humans; Lung Neoplasms; Male; Mesothelioma; Middle Aged; Mining; Montana; Occupational Exposure; Pleural Neoplasms; Retrospective Studies

Herein is reported the health surveillance document agreed upon during the Consensus Conference held in Rome at the Istituto Superiore di Sanità last year. The aim of the consensus conference was to define guidelines for epidemiologic and health surveillance of the resident population in the area of the Basilicata region exposed to tremolite pollution (Local Health Unit 3 territory Lagonegro, PZ). The health surveillance program for residents and the nested epidemiologic study evaluates for each resident willing to participate, individual exposure with a personal dosimeter, as well as the prevalence of obstructive, restrictive or mixed pulmonary functional patterns, searching for fiber and asbestos bodies in induced-sputum, the prevalence of non malignant asbestos disturbances related to pleural anomalies and, last but not least, provides information on risks and sensitization, advising on personal behaviour that could reduce the risks.

Topics: Asbestos, Amphibole; Asbestosis; Environmental Exposure; Humans; Population Surveillance; Practice Guidelines as Topic; Rome

The community of Libby, Montana has recently been the focus of national attention secondary to widespread amphibole contamination associated with vermiculite mining and processing.. Patients who had occupational and non-occupational exposure to amphibole asbestos in Libby, Montana were evaluated for progressive loss of pulmonary function.. Of the 123 patients evaluated, 94 demonstrated average age-corrected accelerated loss per year of vital capacity at 3.2%, total lung capacity (TLC) 2.3%, and DLCO 3.3%. All patients all had predominantly pleural changes with minimal to no interstitial disease.. The study demonstrates a progressive loss of pulmonary function in patients exposed to tremolite asbestos.

Topics: Aged; Asbestos, Amphibole; Asbestosis; Disease Progression; Female; Humans; Male; Mining; Montana; Occupational Exposure; Pleural Diseases; Prevalence; Respiratory Function Tests; Risk Factors

Lung tissue from 15 women who died from mesothelioma was evaluated for tissue burden of ferruginous bodies and uncoated asbestos fibers. The group contained individuals who had occupational exposure to asbestos and others had family members whose work history included vocations where contact with asbestos containing materials occurred.. Tissue samples from tumor free lung were digested and filtered and then investigated for ferruginous bodies by light microscopy and asbestos and non-asbestos fibers by analytical transmission electron microscopy (ATEM). Size and type of fibers were also analyzed.. Asbestos bodies were found in 13 of the 15 samples and asbestos fibers were found in all cases. The most commonly found uncoated asbestos fiber in these individuals was amosite whereas tremolite was the second most commonly found form. The asbestos fiber burden in these females was often of mixed types.. The asbestos body and fiber burden in these cases show variation in tissue burden. Some cases in this study had appreciable burden, which was attributed to secondhand exposure from occupationally exposed family members. Mesothelioma can occur also in individuals with comparatively low tissue burdens of asbestos.

Topics: Aged; Aged, 80 and over; Asbestos, Amosite; Asbestos, Amphibole; Asbestos, Crocidolite; Asbestosis; Body Burden; Environmental Exposure; Female; Humans; Lung; Lung Neoplasms; Mesothelioma; Microscopy, Electron; Middle Aged; Mineral Fibers; Occupational Exposure; Reproducibility of Results

Inhabitants of Metsovo in northwest Greece have been exposed to asbestos from use of a tremolite-containing whitewash ("luto" soil). As a result, they have increased incidence of malignant pleural mesothelioma and pleural calcifications (PCs). However, subjects with calcifications have a much lower incidence of mesothelioma than those without. A previous study of the two groups with BAL revealed higher proportional lymphocytosis among subjects with calcifications. We suggested that BAL lymphocytosis may be somehow correlated with "protection" against neoplasia.. The present report is a study of the liquid phase of BAL in the two groups. BAL specimens of 43 Metsovites (13 subjects with PCs and 30 subjects without PCs) and two control groups were examined. We measured total protein, albumin, IgG, IgA, and interleukin-6. Proteins were analyzed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and two-dimensional electrophoresis and further characterized using an appropriate computer program.. The most interesting finding was the presence of two additional protein spots corresponding to the electrophoretic site of Ig heavy chain and C(4) component of complement. The two proteins were present in all Metsovites with PCs but in none without PCs and also in none of the control groups.. This study further separates two groups of Metsovites with different reaction to asbestos, possibly as a result of different activation of alveolar macrophages. This difference leads the first group to the formation of PCs, BAL fluid lymphocytosis, and relative "protection" against malignancy, and the second group to no calcifications, no lymphocytosis, but also no protection against malignancy.

Topics: Adult; Aged; Asbestos, Amphibole; Asbestosis; Bronchoalveolar Lavage Fluid; Calcinosis; Complement C4; Environmental Exposure; Female; Greece; Humans; Immunoglobulin A; Immunoglobulin G; Immunoglobulin Heavy Chains; Interleukin-6; Lymphocytosis; Male; Mesothelioma; Middle Aged; Pleural Diseases; Pleural Neoplasms; Prognosis; Proteins

Environmental exposure to tremolite and erionite causes endemic diseases of the lung and pleura in Turkey. This study aimed to evaluate the impact of these exposures and further occupational exposures on fibre-related diseases in Turkish immigrants living in Belgium. The study included 51 males and 17 females that emigrated < 1-38 yrs ago. Most of them (n=46) had nonmalignant pleural lesions, one had asbestosis and one had mesothelioma. Environmental asbestos exposure was likely for the majority of patients (60%), but there were also reports of possible occupational asbestos (n = 14) and erionite (n = 2) exposure. Tremolite was the main fibre type in bronchoalveolar lavage fluid (BALF). Elevated concentrations of amosite or crocidolite were detected in only two patients. The delay elapsed since the end of the environmental exposure had no influence on the asbestos body or the tremolite fibre concentrations in the BALF of Turkish immigrants. Most fibre-related diseases in Turkish immigrants are probably due to environmental rather than occupational exposure. Precise information about geographical origin and occupation should be obtained when investigating these patients. Mineralogical analysis of bronchoalveolar lavage fluid gives valuable information on the type and intensity of exposure, especially in patients with both environmental and occupational exposure.

Topics: Adult; Aged; Asbestos, Amphibole; Asbestosis; Belgium; Emigration and Immigration; Environmental Exposure; Female; Humans; Male; Mesothelioma; Middle Aged; Mineral Fibers; Occupational Exposure; Pleural Neoplasms; Pneumoconiosis; Turkey; Zeolites

Topics: Aluminum Silicates; Asbestos, Amphibole; Asbestosis; Humans; Maximum Allowable Concentration; Mining; Neoplasms; United States; United States Environmental Protection Agency

The health effects of asbestos are intimately related to the fate of inhaled fibers in the lungs. The kinetics of asbestos fibers have been studied primarily in rodents. The objective of this study was to explore the application of these kinetic models to human autopsy data.. We analyzed the asbestos fiber content of the lungs of 72 Quebec chrysotile miners and millers and 49 control subjects using analytical transmission electron microscopy. Statistical methods included standard multivariate linear regression and locally weighted regression methods.. The lung burdens of asbestos bodies and chrysotile and tremolite fibers were correlated, as were the concentrations of short, medium, and long fibers of each asbestos variety. There were significant associations between the duration of occupational exposure and the burdens of chrysotile and tremolite. The concentration of chrysotile decreased with the time since last exposure but the concentration of tremolite did not. The clearance rate varied inversely with the length of chrysotile fibers. For fibers greater than 10 mu in length the clearance half-time was estimated to be 8 years.. The patterns in our data are compatible with both of the hypotheses suggested from rodent experiments; the existence of a long-term sequestration compartment and overload of clearance mechanisms in this compartment.

Topics: Aged; Aged, 80 and over; Asbestos, Amphibole; Asbestos, Serpentine; Asbestosis; Case-Control Studies; Humans; Lung Neoplasms; Male; Mesothelioma; Metabolic Clearance Rate; Microscopy, Electron; Middle Aged; Mineral Fibers; Mining; Multivariate Analysis; Regression Analysis

Environmental or domestic exposure to asbestos fibers originating from local soil is responsible for a high incidence of diseases in large rural areas of Turkey. Bronchoalveolar lavage fluids (BALF) were obtained for 65 Turkish subjects originating from these areas and for 42 Turkish controls. Asbestos bodies (ABs) and uncovered fibers (UFs) were quantified by phase contrast light microscopy. Total fiber burden was determined by transmission electron microscopy. The main asbestos types disclosed were tremolite and to a lesser extent chrysotile. AB and fiber concentrations were higher in environmentally exposed subjects (geometric mean [geometric standard deviation]: 5.20 [6.22] AB/ml, 444 [11.6] tremolite fibers/ml) than in control subjects (0.22 [1.45] AB/ml, 12.0 [15.4] tremolite fibers/ml) (p < 0.001). In subjects environmentally exposed in Turkey, AB burdens on tremolite were in the same range as those on commercial amphiboles in subjects occupationally exposed in Belgium. In Turkish subjects, values above either 1 AB/ml, 3 uncovered fiber/ml in light microscopy, or 300 fibers/ml in electron microscopy indicated usually an abnormal alveolar retention reflecting a significant cumulative exposure from environmental or domestic origin. These observations are probably valid for other areas in the world where diseases associated with environmental exposure to soil- derived asbestos fibers occur and for immigrants originating from these areas.

Topics: Adult; Aged; Asbestos; Asbestos, Amphibole; Asbestos, Serpentine; Asbestosis; Belgium; Bronchoalveolar Lavage Fluid; Carcinogens; Emigration and Immigration; Environmental Exposure; Female; Humans; Incidence; Male; Microscopy, Electron; Microscopy, Phase-Contrast; Middle Aged; Mineral Fibers; Occupational Exposure; Reproducibility of Results; Rural Health; Soil; Turkey

About 8% of our cases of mesothelioma occur in women, with a median age of 59 years. Our percentage is lower than other series reported in the literature because of the large number of occupationally exposed men referred to our laboratory. Tumor arose in the pleura in 86% of the women in our study, and the majority were epithelial. Pleural plaques were found in half of the women for which this information was available, and asbestosis was found in only 16%. A history of exposure to asbestos was identified in three quarters of the women, more than half of whom were household contacts of asbestos workers. Occupational exposure to asbestos was identified in only 19% of patients. An elevated tissue asbestos burden was noted in 70% of women from whom lung tissue was available for analysis. The main fiber type identified was amosite, followed by tremolite and chrysotile. These findings and those from other countries suggest a need for reassessment of the background rate of mesothelioma in industrialized nations.

Topics: Adult; Aged; Aged, 80 and over; Asbestos, Amosite; Asbestos, Amphibole; Asbestos, Serpentine; Asbestosis; Female; Humans; Male; Mesothelioma; Middle Aged; Mineral Fibers; Peritoneal Neoplasms; Peritoneum; Pleura; Pleural Neoplasms

Tremolite is nearly ubiquitous and represents the most common amphibole fiber in the lungs of urbanites. Tremolite asbestos is not mined or used commercially but is a frequent contaminant of chrysotile asbestos, vermiculite, and talc. Therefore, individuals exposed to these materials or to end-products containing these materials may be exposed to tremolite. We have had the opportunity to do asbestos body counts and mineral fiber analysis on pulmonary tissue from five mesothelioma cases and two asbestosis cases with pulmonary tremolite burdens greater than background levels. There were no uncoated amosite or crocidolite fibers detected in any of these cases. Three patients were occupationally exposed to chrysotile asbestos; two patients had environmental exposures (one to vermiculite and one to chrysotile and talc) and one was a household contact of a shipyard worker. The tremolite burdens for the asbestosis cases were one to two orders of magnitude greater than those for the mesothelioma cases. Our study confirms the relationship between tremolite exposure and the development of asbestos-associated diseases. Furthermore, the finding of relatively modest elevations of tremolite content in some of our mesothelioma cases suggests that, at least for some susceptible individuals, moderate exposures to tremolite-contaminated dust can produce malignant pleural mesothelioma.

Topics: Adult; Aged; Asbestos; Asbestos, Amphibole; Asbestosis; Environmental Exposure; Female; Humans; Lung Neoplasms; Male; Mesothelioma; Middle Aged; Occupational Exposure

Chrysotile formation arises through serpentinization of ultramafics and silicified dolomitic limestones. Rock types tend to control the trace metal content and both the nature and amounts of admixed minerals in the ore, such as fibrous brucite (nemalite) and tremolite. Some associated minerals and trace metals are thought to play a role in biological potential. Tremolite, one of the important associated minerals, may occur with different morphological forms, called habits. These habits range from asbestiform (tremolite asbestos) to common blocky or non-fibrous form (tremolite cleavage fragments). The latter is most common in nature. Tremolite in chrysotile ore varies in habit and concentration, both factors determining the degree of risk following inhalation. Tremolite fibre is thought to be important in relation to the occurrence of mesothelioma. Chrysotile fibrils may vary in diameter. Dust clouds generated following manipulation vary in fibre number and surface area. Chrysotile fibres exhibit a range of physical characteristics. The fibre may be non-flexible ('stiff') and low in tensile strength ('brittle'), and may lack an ability to curl. This fibre, referred to as 'harsh', sheds water more quickly than its curly, flexible 'soft' variety. The behaviour of the harsh fibres is more amphibole-like and their splintery nature suggests an enhanced inhalation potential. Slip fibre ore from Canada tends to contain more fibrous brucite (nemalite) than cross-fibre ore in the same mine. Industrial manipulation, which includes chemical treatment, heating and milling, may impart new surface properties to chrysotile dusts. Biological potential may be enhanced (opening of fibre bundles) or reduced (disruption of surface bonds and lessened ability to interact with organic moieties). Leaching of magnesium from chrysotile occurs at a pH less than about 10. Chrysotile has been demonstrated to lose magnesium in vivo and undergo clearance from the lung. The biological potential of magnesium-depleted chrysotile is much reduced, or even eliminated. Reduction of mesothelioma-inducing and cytotoxic potential has been observed and quantified experimentally. Use of chrysotile products in high-temperature environments may heat the mineral to the point where it undergoes alteration of properties, especially by dehydroxylation. Chrysotile ore may vary in properties and associated minerals: it may form aerosols with different size distributions, especially fibre/fibril diameters a

Topics: Asbestos, Amphibole; Asbestos, Serpentine; Asbestosis; Humans; Lung Neoplasms; Mesothelioma; Pleural Neoplasms; Research; Surface Properties; Trace Elements

Studies of human lungs indicate that, for virtually all types of exposure, the relative proportion of amphibole asbestos retained in the lung far exceeds the proportion in the original dust and, conversely, the relative proportion of chrysotile is far less than that in the original dust. Although amphiboles appear to accumulate in lung in proportion to exposure and chrysotile does not, failure of chrysotile deposition is probably not the reason for the disproportionate retention of amphibole fibres. The available data suggest that chrysotile is deposited in the parenchyma but is cleared extremely rapidly, with the vast bulk of fibres removed from human lungs within weeks to months after inhalation; by comparison, amphibole clearance half-lives are of the order of years to decades. The mechanisms of preferential chrysotile clearance remain uncertain, but fragmentation of chrysotile into short fibres, possibly accompanied by extremely rapid dissolution of such fibres, appears to be important in this process. Chrysotile fibres do penetrate to the periphery of the lung, so that differences in mesothelial pathogenicity of chrysotile and amphiboles in regard to mesothelioma are not caused by failure of chrysotile to reach the pleura. The theory that the tremolite contaminant rather than the chrysotile itself is the cause of 'chrysotile-induced' disease (especially mesothelioma) is consistent with the available human data, but the contrary ideas that disease is caused either by the total transient burden of inhaled chrysotile fibres or by a small, sequestered, long-retained fraction of chrysotile fibres still need to be excluded.

Topics: Animals; Asbestos, Amosite; Asbestos, Amphibole; Asbestos, Crocidolite; Asbestos, Serpentine; Asbestosis; Guinea Pigs; Humans; Lung; Mesothelioma; Mining; Occupational Exposure; Pleura; Pleural Neoplasms; Textile Industry; Time Factors

Topics: Asbestos; Asbestos, Amosite; Asbestos, Amphibole; Asbestos, Crocidolite; Asbestos, Serpentine; Asbestosis; Humans; Mesothelioma; Pleural Neoplasms; Risk Factors

To attempt to determine the mineralogic factors that relate to the appearance of specific types of asbestos-related disease in workers with heavy mixed exposure to amphiboles and chrysotile, we analyzed the pulmonary asbestos fiber burden in a series of 144 shipyard workers and insulators from the Pacific Northwest. Amosite was found in all lungs, and tremolite and chrysotile in most lungs, but the vast majority of fibers were amosite. Tremolite and chrysotile concentrations were significantly correlated, indicating that the tremolite originated from chrysotile products, but no correlation was found between tremolite or chrysotile concentration and amosite concentration. Time since last exposure was correlated with decreasing amosite concentration and the calculated clearance half time was about 20 yr. In a multiple regression analysis that accounted for the presence of more than one disease in many subjects, a high concentration of amosite fibers was correlated with the presence of airway fibrosis and asbestosis, whereas subjects with mesothelioma, lung cancer, pleural plaques, or no asbestos-related disease had about the same, much lower, amosite concentration. No relationship was found between the concentration of chrysotile or tremolite and any disease. Analysis of fiber size measures (length, width, aspect ratio, surface, mass) showed that pleural plaques were strongly associated with high aspect ratio amosite fibers and suggested that mesotheliomas were associated with low aspect ratio amosite fibers.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Aged; Aged, 80 and over; Asbestos, Amosite; Asbestos, Amphibole; Asbestos, Serpentine; Asbestosis; British Columbia; Construction Materials; Female; Humans; Lung; Male; Middle Aged; Northwestern United States; Occupational Exposure; Regression Analysis; Ships; Time Factors

Retention patterns in lung tissue (determined by transmission electron microscopy and energy dispersive spectrometry) of chrysotile, tremolite, and crocidolite fibres were analysed in 69 dead asbestos cement workers and 96 referents. There was an accumulation of tremolite with time of employment. Among workers who died within three years of the end of exposure, the 13 with high tremolite concentrations had a significantly longer duration of exposure than seven in a low to intermediate category (medians 32 v 20 years; p = 0.018, one sided). Crocidolite showed similar patterns of accumulation. In workers who died more than three years after the end of exposure, there were no correlations between concentrations of amphibole fibres and time between the end of exposure and death. Chrysotile concentrations among workers who died shortly after the end of exposure were higher than among the referents (median difference in concentrations 13 million fibres (f)/g dry weight; p = 0.033, one sided). No quantitative differences in exposure (duration or intensity) could be shown between workers with high and low to intermediate concentrations. Interestingly, all seven workers who had had a high intensity at the end of exposure (> 2.5 f/ml), had low to intermediate chrysotile concentrations at death, whereas those with low exposure were evenly distributed (31 subjects in both concentration categories); hence, there was a dependence between last intensity of exposure and chrysotile concentration (p = 0.014). Among 14 workers with a high average intensity of exposure, both those (n = 5) with high tissue concentrations of chrysotile and those (n = 10) with high tissue concentrations of tremolite fibres had more pronounced fibrosis than those with low to intermediate concentrations (median fibrosis grades for chrysotile: 2 v 1, p = 0.021; for tremolite: 2 v 0.5, p = 0.012). Additionally, workers who died shortly after the end of exposure with high concentrations of chrysotile and crocidolite had smoked more than those with low intermediate concentrations (medians for chrysotile 35 v 15 pack-years, p = 0.030; for crocidolite 37 v 15 pack-years, p = 0.012). The present data indicate that chrysotile has a relatively rapid turnover in human lungs, whereas the amphiboles, tremolite and crocidolite, have a slower turnover. Further, chrysotile retention may be dependent on dose rate. Chrysotile and crocidolite deposition and retention may be increased by tobacco smoking; chrysotile

Topics: Aged; Asbestos, Amphibole; Asbestos, Crocidolite; Asbestos, Serpentine; Asbestosis; Female; Humans; Industry; Lung; Male; Microscopy, Electron; Occupational Exposure; Silicate Cement; Smoking; Time Factors

Diagnosis of asbestosis and bronchiolo-alveolar carcinoma was made in a 55-year-old Turkish woman who was a nonsmoker. She originated from and was living in an area with a high prevalence of environmental diseases attributed to tremolite asbestos. Mineralogic analysis of lung tissue revealed very high concentrations of asbestos bodies (1.64 x 10(6)/g of dry tissue) and tremolite fibers (173.7 x 10(6) of dry tissue). This case illustrates the following points: (1) In some areas, environmental exposure can lead to cumulated fiber retention comparable to occupational exposure and thus can represent a risk for lung fibrosis (asbestosis). (2) Lung cancer as a complication of environmental asbestosis also should be considered as a potential environmental disease.

Topics: Adenocarcinoma, Bronchiolo-Alveolar; Asbestos, Amphibole; Asbestosis; Environmental Exposure; Female; Humans; Lung Neoplasms; Middle Aged

To examine how fiber type, fiber concentration, and fiber size correlate with the presence of asbestos-related disease in workers with heavy chrysotile exposure, we used analytic electron microscopy to determine the fiber content of the lungs of 94 long-term chrysotile miners and millers from the region of Thetford Mines, Quebec. Mesothelioma, airway fibrosis, and asbestosis were strongly associated with a high tremolite fiber concentration, whereas pleural plaques and carcinoma of the lung showed no relationship to tremolite burden. Similar patterns were seen for chrysotile concentration, but further analysis suggested that the apparent effect of chrysotile probably was due to the high correlation (r = 0.70) between chrysotile and tremolite concentration rather than to an independent effect of chrysotile. Increased tremolite-chrysotile ratio was marginally associated with the presence of pleural plaques but not with any other disease. Very high correlations (r > 0.90) between the concentrations of fibers longer or shorter than 8 microns prevented assessment of the effects of long compared with short fibers. Pleural plaques were very strongly associated with higher mean tremolite fiber aspect ratios, but no differences in mean fiber size (length, width, aspect ratio, surface area, and mass) were seen for any other disease. Total fiber size measures (total fiber length/g and others) showed differences similar to fiber concentration for mesothelioma, airways fibrosis, and asbestosis, but no one measure was clearly better than another or better than fiber concentration. We conclude that, in this population of heavily exposed chrysotile miners and millers, the presence of airways fibrosis and asbestosis and, probably, mesothelioma reflects high tremolite burden.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aged; Asbestos; Asbestos, Amphibole; Asbestos, Serpentine; Asbestosis; Humans; Lung; Lung Neoplasms; Mesothelioma; Microscopy, Electron; Middle Aged; Mining; Particle Size; Pleural Diseases; Pulmonary Fibrosis; Quebec; Regression Analysis; Silicic Acid

The purpose of this study was to determine whether the inhabitants of villages environmentally exposed to asbestos, in northeast Corsica, had a higher incidence of pleural plaques. X-rays were obtained from subjects aged over 50 yrs, with no occupational exposure to asbestos or history of pleural disease, in one village exposed to asbestos, Murato, and a nonexposed, control village, Vezzani. In addition, the mineral content of the air and parietal pleura of animals in the exposed zone was studied, using transmission electron microscopy. The incidence of bilateral pleural plaques in the exposed population was 41%, as compared to 7.5% in the nonexposed population (p < 0.00001). The levels of airborne tremolite were higher in Murato (6-72 ng.m-3) than in Vezzani (< 1 ng.m-3), but chrysotile levels were similar. Significant numbers of chrysotile and tremolite fibres were identified in the parietal pleura of animals from the exposed village. This study confirms the well-known correlation between bilateral pleural plaques and environmental exposure to low levels of asbestos.

Topics: Aged; Air Pollutants; Animals; Asbestos; Asbestos, Amphibole; Asbestos, Serpentine; Asbestosis; Dogs; Environmental Exposure; Female; France; Goats; Humans; Incidence; Male; Middle Aged; Pleura; Pleural Diseases; Prevalence; Silicic Acid

Endemic PCs and high incidence of malignant mesothelioma from household use of asbestos have been reported in Metsovo in northwestern Greece ("Metsovo lung"). In the present study, we present similar findings in six more areas of Greece. Like Metsovo, all these areas are located within ophiolite belts. Like Metsovo, material similar to "Metsovo whitewash" has been used for various domestic uses. Asbestos fibers (chrysotile, antigorite and tremolite) were found in three of the six areas. Also, in two, MPM has been diagnosed. These findings suggest that "Metsovo lung" occurs in several areas of Greece and has similar etiology and epidemiology.

Topics: Aged; Asbestos; Asbestos, Amphibole; Asbestosis; Calcinosis; Environmental Exposure; Greece; Humans; Incidence; Mesothelioma; Middle Aged; Pleural Diseases; Pleural Neoplasms; Silicic Acid; Soil

To determine which mineral parameters relate to the degree of interstitial fibrosis (asbestosis) in the lungs of chrysotile miners and millers, we graded fibrosis histologically and correlated fibrosis grades with fiber concentration and mean size, surface area, and mass, and with total sample fiber length, surface area, and mass in 21 cases. A positive correlation of fibrosis grade with tremolite concentration and a lesser correlation with chrysotile concentration was found for whole lungs, specific sites within lungs, and, for tremolite, single microscopic fields. No correlations were found for measures of chrysotile fiber size, surface area, or mass, but tremolite mean fiber length, aspect ratio, and surface area were, surprisingly, negatively correlated with fibrosis grade. Measures based on total rather than on mean case or site parameters failed to show correlations with fibrosis. We conclude that: (1) degree of pulmonary fibrosis reflects fiber concentration at both a bulk and a microscopic level; (2) mean fiber length and parameters related to mean fiber length also correlate with fibrosis grade, but, contrary to predictions from animal studies, this correlation is negative, suggesting that short fibers may be more important in the genesis of pulmonary fibrosis than is commonly believed; (3) there is no evidence that parameters such as total fiber length, surface area, or mass provide predictors of degree of fibrosis.

Topics: Aged; Asbestos; Asbestos, Amphibole; Asbestos, Serpentine; Asbestosis; Humans; Lung; Male; Microscopy, Electron; Mining; Silicic Acid

We report four cases of pleural plaques found at autopsy in individuals who resided in or near the chrysotile mining town of Thetford Mines, Quebec, and who had never been employed in the chrysotile mining and milling industry. Three of these patients were farmers, and one was a road construction worker. Lung asbestos content of these cases was compared with that of a group of nine persons living in the same vicinity who did not have pleural plaques. The plaque group was found to have an equal chrysotile content but about a fourfold elevation in median tremolite content, a statistically significant increase. Fiber sizes were the same in both groups. Also, one plaque case had an elevated level of relatively long titanium oxide fibers. These observations suggest that environmental pleural plaques in this region of Quebec are probably caused by exposure to tremolite derived from local soil and rock and that other types of mineral fibers such as titanium oxide may occasionally also be the cause of such lesions.

Topics: Aged; Asbestos; Asbestos, Amphibole; Asbestos, Serpentine; Asbestosis; Environmental Pollution; Humans; Lung; Male; Mining; Pleural Diseases; Quebec; Silicic Acid; Silicon Dioxide; Titanium

Topics: Asbestos, Amphibole; Asbestosis; Humans; Mesothelioma; Pleural Neoplasms; Risk Factors; Silicic Acid; Silicon Dioxide

Topics: Adult; Asbestos; Asbestos, Amphibole; Asbestosis; Environmental Exposure; Female; Hodgkin Disease; Humans; Male; Mesothelioma; Middle Aged; Pleural Neoplasms; Rural Population; Silicic Acid; Stomach Neoplasms; Turkey

Topics: Aged; Asbestos; Asbestos, Amphibole; Asbestosis; Environmental Exposure; Greece; Humans; Silicic Acid