Elongated particulate burden in an individual who died of mesothelioma and had an occupational history as a talc "mucker".

INTRODUCTION: Tissue from a 77-year-old man diagnosed with mesothelioma was referred with a request for identification of the presence of fibrous structures in tissue samples. The individual's work history including working as a "mucker" at a specific "industrial" talc mine. METHODS: Ferruginous bodies in the tissue digests as well as asbestos fibers were found. A bulk sample of a talc containing product from that mine was also analyzed. DISCUSSIONS/CONCLUSIONS: The correlation between the unique asbestos mineral/fibrous content of the talc to which he was exposed and findings of the same type of asbestos found in his lung is discussed. The type of asbestos found (tremolite) is a "non-commercial" type of asbestos that has been identified in some talc deposits. Tremolite, like all forms of asbestos is a causative agent for mesothelioma-the disease from which this individual suffered.

A clinical evaluation and tissue fiber burden analysis of a lifetime resident of Libby, Montana with adenocarcinoma of the lung.

INTRODUCTION: Vermiculite mining operations near Libby, Montana were active from the 1920s to 1990. Rail facilities for shipment of the mined material as well as some vermiculite processing activities were ongoing within the community of Libby. A fibrous component within the mined material has been associated with asbestos-related diseases in vermiculite miners and in the local citizens of the community. CLINICAL HISTORY/METHODS: We present a clinical case history and tissue fiber burden analysis of an individual with a multifocal adenocarcinoma of the lung who was a lifelong resident of Libby and whose history of exposure was as a member of the general population there. RESULTS/DISCUSSION: To our knowledge this is the first time tissue from a member of the general population of Libby, Montana has been evaluated and shown to contain an appreciable presence of "Libby amphibole" fibers.

Tissue burden evaluation of elongated mineral particles in two individuals with mesothelioma and whose work history included manufacturing tile.

Two cases with diagnosis of mesothelioma were referred to our laboratories with a request for tissue burden analysis in order to determine the presence of ferruginous bodies and uncoated elongated mineral particles in tissue samples. The individuals shared in common a past background of working in tile manufacturing facilities where industrial talc was used in the production of the products. Both were found to have ferruginous bodies in their lung tissues as well as elongated talc fibers/ribbons and elevated numbers of noncommercial amphiboles in their tissues. To our knowledge, this is the first report of tissue assessment for the presence of elongated mineral particles in individuals whose exposures to talc occurred were while working in the manufacture of tile products and who developed the fiber-related cancer - mesothelioma.

A clinical assessment and lung tissue burden from an individual who worked as a Libby vermiculite miner.

During its days of operation (1920s-1990), the world's largest source of vermiculite was extracted from a mine located near Libby, Montana. The material mined at this site was shipped for various commercial applications to numerous sites in the United States. There was a "fibrous" component with toxic potential within the vermiculite deposit that has resulted in "asbestos-like" diseases/deaths being reported in numerous studies involving miners as well as residents of the town of Libby. The present case involves the clinical assessments of an individual who worked at the mine from 1969 to 1990. He had no other known occupational exposures to fibrous materials. He developed a clinical picture that included "asbestos-like" pathological features and eventually an adenocarcinoma. The clinical assessment including radiographic features will be presented. The evaluation will also include the analytical evaluation of the fibrous/ferruginous body composition of the lung tissue. This is to our knowledge the first time such an extensive evaluation has been conducted in a vermiculite miner from Libby, Montana.

Biodurability/retention of Libby amphiboles in a case of mesothelioma.

Mesothelioma is considered a signal tumor for exposure to asbestos (fibrous materials) and can occur decades after first exposure. The present case study reports on tissue burden of fibrous dust in a person who used a vermiculite material (Zonolite) as an attic insulator some 50 years prior to her death. The exposure occurred in two construction/renovation projects in her private residencies. She potentially had exposures to wall board/joint compounds during renovations. She additionally was reported to occasionally be involved in occupational activity, including drilling holes in presumed asbestos-containing electrical boxes. The tissue burden analysis revealed the presence of noncommercial amphibole asbestos fibers and consistent presence in the lung and lymph samples of Libby amphibole fibers. The findings of Libby amphibole fibers in human tissue can be attributed to exposure to Libby vermiculite. This study illustrates that analytical transmission electron microscopy can distinguish these structures from "asbestos" fibers. Further, the findings indicate that a population of these structures is biodurable and retained in the tissue years after first/last exposure.

Mesothelioma in an individual following exposure to crocidolite-containing gaskets as a teenager.

Mesothelioma is considered a signal tumor for asbestos exposure and typically occurs decades after first exposure to asbestos. Tissue analysis often indicates past exposure to mixed types of asbestos. This report describes the case of a 58-year-old man who developed mesothelioma after reported exposure to crocidolite from asbestos-containing gaskets beginning at age 16 during three summers during high school and for approximately four hours per day during the last semester of his senior year. He had no further known exposure to asbestos. Analytical transmission electron microscopy analysis of digested tissue samples revealed elevated levels of crocidolite asbestos fibers and the presence of crocidolite cored ferruginous bodies. This case is unique in that it establishes that relatively short and/or intense exposures to crocidolite asbestos traumatically released from a previously classified Category 1 nonfriable asbestos-containing material (NESHAP) was confirmed via tissue burden analysis years following the historically defined exposures.

A technical comparison of evaluating asbestos concentration by phase-contrast microscopy (PCM), scanning electron microscopy (SEM), and analytical transmission electron microscopy (ATEM) as illustrated from data generated from a case report.

As reported in the literature, there are more than 30 different standard methods available for the analysis of asbestos in a variety of situations. The methods include those for determining asbestos concentration in air, water, bulk building materials, surface dust, soil, and lung tissue (Millette, 2006; Dodson, 2006). Knowledge of the various methodologies is essential in determining which methodology is appropriate for any given situation. To better understand the use of various techniques in evaluating asbestos, we use an example of an individual who was a machinist in an auto supply/parts business. His work activity during much of his professional career included grinding, arcing, and drilling brake components. Asbestos has been identified as an important component of friction products, particularly brakes, and exposure to asbestos brake dust is of concern, particularly in workers where grinding, arcing, sanding, and drilling of brake components are recognized as releasing appreciable dust. Various methods can be used to evaluate asbestos in tissue and air. The case reported herein was of an individual who died from a pleural mesothelioma. Paraffin-embedded lung tissue was examined by a laboratory using scanning electron microscopy (SEM) and was reported to contain elevated asbestos body concentrations and five fibers, of which two were asbestos (one chrysotile and one tremolite). Tissue from the same paraffin block was analyzed by the laboratory of one of us (RFD) using analytical transmission electron microscopy (ATEM). While one might think the number of asbestos bodies and fibers would be similar using SEM and ATEM, this was not the case. Slightly elevated numbers of ferruginous asbestos bodies were detected in the digestate by light microscopy. Large numbers of uncoated chrysotile fibers were found by ATEM, but not by SEM. The majority of the chrysotile structures were fibrils whose detection required resolution levels attainable only at higher magnification by ATEM. The findings in this case clearly indicate that analysis of lung tissue digestates by ATEM at a higher magnification (15,000x) identifies significant numbers of asbestos fibers that are not identified by SEM at 1000x. These results further indicate that if causation of an asbestos-induced disease such as mesothelioma is based on asbestos concentration of lung tissue, erroneous conclusions can be made by analyzing tissue only by SEM. Thus, the methodologies that are available to analyze asbestos in lung tissue are extensively discussed here with respect to the type of procedure that should be utilized in various situations.