Asbestos Tissue Burden Study on Human Malignant Mesothelioma.

Abstract

Asbestos fibers in the lung and mesothelial tissues (mesotheliomatous tissue and hyaline plaque) taken from 151 human malignant mesothelioma cases were identified and characterized by high resolution analytical electron microscopy. Asbestos fibers were present in almost all of the lung tissue as well as in the mesothelial tissue. The most common asbestos types seen in the lung were an admixture of chrysotile with amphiboles followed by amphiboles alone and chrysotile alone. The majority of asbestos types seen in the mesothelial tissues were chrysotile alone, followed by chrysotile plus amphibole and amphibole alone. A disproportion of asbestos types between the lung and mesothelial tissues was frequently observed. The most common pattern of the disproportion was chrysotile plus amphibole(s) in the lung and chrysotile only in the mesothelial tissues, followed by amphibole(s) in the lung and chrysotile only in the mesothelial tissues. Such a disproportion was considered to have been caused by chrysotile fiber's strong capacity to translocate from the lung to mesothelial tissues. The number of asbestos fibers in the lung was 456.4 × × × × × 10 6 fibers/dry gram in maximum, 0.08 × × × × × 10 6 fibers/dry gram in minimum and 105 × × × × × 10 6 fibers/dry gram on average; in the mesothelial tissues it was 240.0 × × × × × 10 6 fibers/dry gram in maximum, 0.03 × × × × × 10 6 fibers/dry gram in minimum and 49.84 × × × × × 10 6 fibers/dry gram on average. These numbers were greater than those seen in the general population. The majority of asbestos fibers detected in the lung and mesothelial tissues were shorter than 5 µm in length. Asbestos fibers fit to Stanton's hypothetical dimensions (≥8.0 µm in length and ≤0.25 µm in diameter) were only 4.0%, since the majority of these fibers were shorter (<8 µm) and thinner (<0.25 µm) fibers. We concluded that such short, thin asbestos fibers should not be excluded from those contributing to the induction of human malignant mesothelioma. The present study supports that chrysotile asbestos can induce human malignant mesothelioma, since, in some of the mesothelioma cases, asbestos fibers detected in both the lung and mesothelial tissues, or lung tissue alone or mesothelial tissues alone were exclusively chrysotile fibers.

Quantitative Analysis of Asbestos Burden in a Series of Individuals with Lung Cancer and a History of Exposure to Asbestos

“…The number of papers is further reduced when a selection is made of those having used counting schemes that were at a sufficient magnification to permit inclusion of asbestos fibers below 5 µm in length as well as the longer, thinner individual fibers either of chrysotile or of the "fibrillar" structures of some amphiboles. These excluded fibers are the predominant forms found in tissue when the counting parameters of the study permit their inclusion Churg & Wiggs, 1985Churg & Vedal, 1994;Becklake & Case, 1994;Suzuki & Yuen, 2001;Dodson et al, 1990Dodson et al, , 1997Dodson et al, , 2000Sebastien et al, 1980;Nolan et al, 1994).…”

A study to evaluate asbestos fiber burden in lung and pleural malignancies

“…Most of the studies were done in occupationally exposed patients, [1,9] and [12] Most of the studies conducted in pleural tissue were done in mesothelioma cases. [1,13] Asbestos exposure and its attribution to the lung cancer was also studied. [14,15] Studies were also conducted to find the asbestos burden in nonoccupationally exposed patients.…”

Mesothelioma in a worker who spun chrysotile asbestos at home during childhood

“…While there has been some disagreement about the potency of chrysotile in causing mesothelioma [Cullen and Baloyi, 1991;Mossman et al, 1990;Landrigan, 1998;Rees et al, 1999;Hodgson and Darnton, 2000;McDonald et al, 2001;Nicholson, 2001;Suzuki and Yuen, 2001], the general consensus is that all forms of commercial asbestos cause human malignant mesothelioma [IPCS, 1998].…”