Investigation and analysis of asbestos fibers and accompanying minerals in biological materials

Abstract

A method is described for isolating asbestos fibers contained in biological tissues. It consists in incinerating the biological material in activated oxygen at 150°C, and attacking the ash by 1N HC1 for 18 hr. The residue is then filtered on a membrane covered with a carbon film. Electron microscope examination of the deposit makes it possible to determine fiber concentrations when the weight or volume of primary material is known, and to make size analyses. By x-ray diffraction, the mineralogical nature of the asbestos is determined by comparison with an aluminum reference diagram. For x-ray diffraction, a micromethod is used, with an ash sample of about 10 μg. These techniques are used for identifying and counting asbestos fibers in small fragments of lungs or other organs. It was found that asbestos fibers generally go along with other minerals which may be abundant. Most fibers found in lung are less than 5 μm long. Counts on lungs of asbestos workers give concentrations often greater than 107 particles per gram of dry tissue. The evolution of inhaled chrysotile seems to be different from that of amphiboles. In the case of pleural mesothelioma, a comparison of fibers within the tumor with fibers in the adjacent parenchyma shows only slight differences in the particle sizes, but marked differences in their nature, with a chrysotile enrichment in the pleural zone. Pleural plaques were analyzed in the same way. After decalcification, many small sized asbestos fibers were found. The same technique is now being used for determining ingested particles. A great number of observations concerning fiber counts, their nature and sizes, and the presence of various clays minerals will be necessary to establish the role of the different factors in the formation of lesions caused by the inhalation or the ingestion of asbestos fibers. ImagesFIGURE 2.FIGURE 3.FIGURE 3.

Quantitative Assessment of Asbestos Fibers in Normal and Pathological Pleural Tissue—A Scoping Review

“…Table 2 reports the number of asbestos fibers found in each tissue; studies are listed in chronological order of publication. Le Bouffant [6] described a method for isolating asbestos fibers in biological tissues. The author analyzed the concentration of asbestos fibers in 12 samples (pleural and lung tissue) from 5 cases (no gender information provided), affected by pleural mesothelioma and pleural fibrosis; the subjects were asbestos workers.…”

“…The studies were performed on autopsy samples or biopsies (some studies did not specify if the biopsies were acquired from autopsies or living patients). Most of the studies (eight) analyzed pleural plaques (or fibrosis) [6,[8][9][10][11][12]15,17]; normal pleural tissue was analyzed in four studies [7,13,14,16] and pleural mesothelioma tissue was analyzed in three studies [6,12,17]. All the studies are a collection of cases which were available to the authors; therefore, the level of evidence associated with these studies is that of a case series.…”

“…Asbestos fibers were detected in 111 samples (78%) and were not detected (or detectable) in 31 samples (22%). Most of the studies reported both chrysotile and amphiboles fibers [6,[9][10][11][12][13][15][16][17]; two studies reported only chrysotile asbestos [7,8] and one study (only one patient) reported amphiboles fibers only [14].…”

“…The PubMed search yielded 184 articles that were independently evaluated by two of the authors (FSV, PC); 57 articles were discarded after reading the title, 58 after reading the abstract, and 59 after checking the full text. The references of each relevant article were manually searched, yielding two more papers; finally we identified 12 studies that fit our inclusion criteria [6][7][8][9][10][11][12][13][14][15][16][17].…”

“…The 12 studies included were published between December 1974 and February 2001. Only 5 articles were published in the 1970s and 1980s [6][7][8][9][10]; most of the articles (7 papers) were published in the 1990s [11][12][13][14][15][16][17]. Remarkably, we could not locate any article fitting our inclusion criteria published in the last 20 years (from 2001 to 2021).…”