Assessment of mineral fibres from human lung tissue

Our plain-English summary of Assessment of mineral fibres from human lung tissue, by J.M. Davis, B. Gylseth, A. Morgan (Thorax, 1986).

The study

• Authors: J.M. Davis, B. Gylseth, A. Morgan
• Journal: Thorax
• Published: 1986;41(3):167-75
• Type of article: Review
• Cited by: 25 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Summary of the article

This review summarised the discussions and conclusions of an international workshop on technical problems in estimating the mineral fibre content of human lung tissue. The workshop was held in Oxford from 17 to 19 September 1984 and was sponsored by the North Atlantic Treaty Organisation and the British Asbestosis Research Council. Its aim was to make results from different laboratories more directly comparable. The authors noted that tissue blocks taken centimetres apart could give fibre counts differing by an order of magnitude. They suggested pooling several blocks from peripheral and central regions of the upper and lower lobes. They reviewed tissue digestion and ashing methods, sources of fibre loss and contamination, light and electron microscopic counting, the definition of a fibre (the 3:1 aspect ratio was retained), and fibre identification by electron diffraction and energy dispersive x ray analysis. They recommended that published work report standard reference points such as fibres longer than 5 µm, together with analytical sensitivity and detection limits. They discussed how fibrosis and the clearance and dissolution of chrysotile complicated relating fibre burden to asbestosis and mesothelioma, and the uncertain role of asbestos bodies. In a recent trial, seven laboratories analysed lungs from six asbestos-exposed individuals. The laboratories agreed well on which cases had high or low fibre levels, but their actual counts correlated poorly. The workshop recommended a three-stage international counting trial organised from Edinburgh.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

This article was a review summarising an international workshop held in Oxford from 17 to 19 September 1984 on technical problems in measuring mineral fibres, including asbestos, in human lung tissue. It reported that tissue blocks taken only centimetres apart may give fibre counts differing by an order of magnitude, and suggested pooling several blocks from central and peripheral regions of both upper and lower lobes. Low temperature plasma ashing normally gave higher counts than chemical digestion. Filtered light microscope preparations were said to give counts five times higher than wet preparations. The review noted that chrysotile is cleared from the lung over time. As a result, workers exposed mainly to chrysotile may show more amphibole fibres at necropsy. In a cited trial, seven laboratories counting fibres from the lungs of six asbestos-exposed people recognised high or low levels well, but their actual counts correlated poorly. The authors concluded that comparing counts from different laboratories is at present dangerous. They described a planned international counting trial to be organised from Edinburgh.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Review article summarising the discussions and conclusions of an international workshop
• Who was studied: No study population of its own. The paper reports on an international workshop of scientists held in Oxford, 17 to 19 September 1984, and reviews published work on fibre counts from human lung tissue.
• Exposure: Mineral fibres in human lung tissue, mainly asbestos: chrysotile and the amphiboles crocidolite, amosite and tremolite. Man made mineral fibres are also mentioned.
• Main results:
  • Fibre counts from tissue blocks taken only centimetres apart may vary by an order of magnitude.
  • The suggested compromise for a single count was to take several tissue blocks from peripheral and central regions of both upper and lower lobes and process them together.
  • Low temperature plasma ashing normally produces higher fibre counts than chemical digestion of tissue alone.
  • Light microscope counts from filtered (Millipore) preparations are known to be five times higher than those from wet preparations.
  • The usual counting definition of a fibre is an aspect ratio greater than 3:1. The workshop resisted changing it, and recommended that published work report at least fibres longer than 5 micrometres.
  • Workers exposed mainly to chrysotile are often found at necropsy to have more amphibole than chrysotile in their lungs. In Canadian chrysotile miners, most of the dust found was tremolite.
  • Lung asbestos counts, mainly amphibole, appear correlated with degrees of pulmonary fibrosis (asbestosis), but the actual figures vary widely.
  • Some cases of mesothelioma have lung fibre counts within the range found in the normal urban population.
  • Only a small proportion of lung fibres, probably no more than 1%, become coated as asbestos bodies.
  • In laboratory comparison schemes, competent laboratories counting standard specimens differed two to four-fold.
  • In a cited exercise, seven laboratories counted fibres from the lungs of six asbestos-exposed individuals. They recognised high or low fibre levels well, but correlation between their actual counts was poor.
• The authors' conclusion: The authors concluded that laboratories may be internally consistent, but comparing counts from different laboratories is at present dangerous. They described a three-stage international counting trial to be organised from Edinburgh.

Topics

Medical terms in this study, explained in our Lexicon: Paraffin Block, Tissue Digestion, Aspect Ratio (Length-to-diameter ratio), Analytical Sensitivity, Fibrosis, Chrysotile, Mesothelioma, Asbestos Bodies.

Related studies

• Determination of mineral fibre in human lung tissue by light microscopy and transmission electron microscopy — A.J. Rogers (1984)
• Analysis and interpretation of inorganic mineral particles in "lung" tissues — A.R. Gibbs, F.D. Pooley (1996)
• Mineral fibres, fibrosis, and asbestos bodies in lung tissue from deceased asbestos cement workers — M. Albin, L. Johansson, et al. (1990)
• Lung dust analysis in the assessment of past exposure of man-made mineral fibre workers — J.C. McDonald, B.W. Case, et al. (1990)
• Beryllium detection in human lung tissue using electron probe X-ray microanalysis — K.J. Butnor, T.A. Sporn, et al. (2003)
• Sectioning and imaging hard mineral fibres in biological tissues — N.F. Johnson, K. Ibe (1981)

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