ferroactinolite and Lung-Neoplasms

The objective of this study is to describe the morphology, molecular structure, and chemistry of amphibole fibers from lung samples from workers in the chrysotile mines at Asbestos and Thetford Mines, Quebec. A fibrous tremolite-actinolite contaminant in an asbestos ore sample from the deposit at Asbestos was used for comparison. Lattice imaging was performed using high-resolution transmission electron microscopy (HRTEM). Silica-rich amorphous coatings (SIRA) that may be related to carcinogenesis are noted on all of the HRTEM photographs of fibers retained in lung, but not on fiber surfaces of the bulk comparison sample. Fibers found in lung samples and in a bulk comparison sample are produced primarily by splitting of thicker crystals and, as such, might not be considered asbestos fibers on the basis of certain mineralogical criteria. Implications of SIRA coatings with respect to carcinogenesis are worthy of further study.

Topics: Air Pollutants, Occupational; Asbestos, Amphibole; Cohort Studies; Lung Neoplasms; Mesothelioma; Microscopy, Electron, Transmission; Miners; Occupational Diseases; Quebec

One of the most significant diseases related to environmental asbestos exposure is malignant mesothelioma (MM). Sivas province is located in the Central Anatolia where asbestos exposure is common. We aimed to study clinical, demographical and epidemiologic features of the patients with MM in Sivas, along with the history of asbestos exposure. In total, 219 patients with MM who were diagnosed in our hospital between 1993 and 2010 were retrospectively analyzed in terms of demographical and clinical features. Rock, soil and house plaster samples were taken from the habitats of those patients and were evaluated with optical microscopy and X-ray diffraction methods. The age of the patients ranged between 18 and 85 years. The male-to-female ratio was 1.4:1. Most of the patients confirmed an asbestos exposure history. The most frequent symptoms of the patients were chest pain (60 %) and dyspnea (50 %). The gap between the start of first symptoms and the diagnosis date was approximately 4 months in average. The plaster materials used in most of the houses were made up of mainly carbonate and silicate minerals and some chrysotile. Ophiolitic units contained fibrous minerals such as serpentine (clino + orthochrysotile) chiefly and pectolite, brucite, hydrotalcite and tremolite/actinolite in smaller amounts. MM is not primarily related to occupational asbestos exposure in our region, and hence, environmental asbestos exposure may be indicted. Yet, single or combined roles and/or interactions of other fibrous and non-fibrous minerals in the etiology of MM are not yet fully understood and remain to be investigated.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Asbestos; Asbestos, Amphibole; Environmental Exposure; Female; Geology; Housing; Humans; Lung Neoplasms; Male; Mesothelioma; Mesothelioma, Malignant; Microscopy, Electron, Scanning; Middle Aged; Turkey; X-Ray Diffraction; Young Adult

Mining and processing of amphibolite is associated with workers' exposure to dust containing asbestos minerals (actinolite, tremolite) and with the presence of respirable fibers, i.e. small particles above 5 microns long and below 3 microns in diameter (with length-to-diameter ratio higher than 3:1). Results of epidemiological and laboratory studies show that such dust may be responsible for the development of cancer in dust-exposed people. This work reports the measurement results of concentrations of total dust, respirable fibers and mineral composition of samples collected in plant mining and processing amphibolite rock. Based on the results, cumulated exposure was calculated for the 10-, 20- and 30-year exposure periods. The cumulated exposure was classified into two categories: 0.1-1.0 f/cm3 years and 1.0-10 f/cm3. x years. It has been found that mining and processing of amphibolite is associated with increased risk of death from mesothelioma--11.2 x 10(-5) (crushers--10 years of exposure) to 240.0 x 10(-5) (miners--30 years of exposure). The risk of excessive mortality from lung cancer was not high (below 1. x 10(-4)) for all workplaces and periods of exposure.

Topics: Adult; Asbestos, Amphibole; Carcinogens; Dust; Environmental Monitoring; Humans; Lung Neoplasms; Maximum Allowable Concentration; Mesothelioma; Mining; Occupational Exposure; Poland; Risk Assessment; Time Factors

The vermiculite ore and concentrate of a mine and mill located near Libby, Montana was found to be contaminated with a fiber of the tremolite/acetinolite series. A study was conducted to estimate the exposure-response relationship for mortality for 575 men who had been hired prior to 1970 and employed at least 1 year at the Montana site. Individual cumulative fiber exposure (fiber-years) was calculated. Results indicated that mortality from nonmalignant respiratory disease (NMRD) and lung cancer was significantly increased compared to the U.S. white male population. For those workers more than 20 years since hire, the standard mortality rate (SMR) for lung cancer (ICDA 162-163) was 84.7, 225.1, 109.3, and 671.3 for less than 50, 50-99, 100-399, and more than 399 fiber-years respectively. Corresponding results for NMRD (ICDA 460-519) were 327.8, 283.5, 0, and 278.4. Based on a linear model for greater than 20 years since hire, the estimated percentage increase in lung cancer mortality risk was 0.6% for each fiber-year of exposure. At 5 fiber-years, the estimated percentage was 2.9% from an unrestricted (nonthreshold) linear model and 0.6% from a survival model.

Topics: Aluminum Silicates; Asbestos, Amphibole; Humans; Lung Neoplasms; Male; Mesothelioma; Minerals; Mining; Montana; Occupational Diseases; Silicon Dioxide; Smoking; Time Factors

The role of chrysotile asbestos in the genesis of mesotheliomas in humans is disputed. We analyzed the asbestos content of the lung in 6 long-term chrysotile miners and millers who had pleural mesotheliomas. In five patients, only chrysotile ore components (chrysotile and tremolite/actinolite/anthophyllite types of amphibole asbestos) were found, while the sixth patient presented both chrysotile ore components and amosite, a type of asbestos that is not derived from the mining process. The mean number of fibers/g dry lung for the 5 patients with mesothelioma containing only chrysotile ore components was higher (chrysotile 64 X 10(6) and tremolite group 540 X 10(6] than in a group of long-term chrysotile miner control subjects who had no asbestos-related disease (chrysotile 23 X 10(6), tremolite group 58 X 10(6], but some patients with mesothelioma had fiber burdens near the mean of the control range. Fiber sizes and aspect ratios in the mesothelioma group were approximately the same as those in the control subjects, and analysis of fiber distribution failed to show any preferential localization in the periphery of the lung. However, the concentration ratio of tremolite in the lungs of the mesothelioma cases compared to the control cases was 9.3, while the ratio of chrysotile was only 2.8. Our findings provide strong evidence that chrysotile mine dust (chrysotile and amphibole components) can produce mesotheliomas in humans; the greater relative amounts of tremolite group amphiboles present in the patients with mesothelioma raise the possibility that these fibers may be important in the pathogenesis of the tumors.

Topics: Aged; Asbestos; Asbestos, Amphibole; Asbestos, Serpentine; Humans; Lung; Lung Neoplasms; Male; Mesothelioma; Middle Aged; Minerals; Occupational Diseases

Oncogenesis and in vitro data (reported elsewhere in detail) are compared on the basis of relative activity by mass and by dimensional fiber parameters. When tumor induction is compared to the number of fibers of various lengths and aspect ratios in the dose in rats to the degree of tumor induction, a degree of difference with the long thin fiber concept of tumorigenesis by mineral fibers is noted. Consistency is re-established, however, when cognizance is taken of the change in the length and aspect ratio that took place during residence in the lung. This change resulted in a severalfold excess for ferroactinolite of all fiber lengths with high aspect ratios, produced as a result of longitudinal splitting of the introduced fibers. The response by mass in the in vitro procedures did not mimic oncogenesis. When mass was so adjusted that there were an equal number of mineral fibers, aspect ratio greater than 3, for dose for the two minerals, agreement was closer in both the rabbit alveolar macrophage toxicity test and the clonal cytotoxicity assay in Chinese hamster ovary cells. When activity was related to the number of mineral fibers, the same aspect ratio computed to have been contained in the mass dose, agreement with the relative induction of lung tumors was closer. In all cases, erythrocyte lysis was more active in reflecting the number of mineral fibers.

Topics: Animals; Asbestos; Asbestos, Amosite; Asbestos, Amphibole; Lung; Lung Neoplasms; Minerals; Pleura; Pleural Neoplasms; Rats; Rats, Inbred F344