Measurement of Fibres in Human Lung Tissues

Our plain-English summary of Measurement of Fibres in Human Lung Tissues, by V. Timbrell (1980).

The study

• Author: V. Timbrell
• Published: BIOLOGICAL EFFECTS OF MINERAL FIBRES (J.C. WAGNER, EDITOR), LYON: IARC SCIENTIFIC PUBLICATIONS, VOLUME 30., PP 113-126 (1980)
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This paper described a method called magnetic alignment and light scattering (MALS) for quickly measuring the fibres left after the organic material in autopsy lung tissue is digested away. The author applied it to residues from 311 lung tissue specimens from 80 subjects. Some of them had been exposed at work or in their surroundings to dust from the Paakkila anthophyllite mine in Finland. Transmission electron microscopy (TEM) was used alongside MALS on the few residues with enough fibres. The fibres were identified as anthophyllite. Among the 12 subjects with the highest fibre mass concentrations, four Paakkila employees ranked highest. Fibres in the lungs were similar in diameter to airborne fibres in the Paakkila mill but differed markedly in length. A three-year-old girl had the highest median fibre diameter and median length of all 80 subjects. The author conjectured that her father's working clothes were the source. The author concluded that childhood exposure to fibres could be particularly dangerous. Because few subjects had TEM analysis, the author said the largest fibre sizes found must be regarded as minimum values.

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: Methods study: a magnetic alignment and light scattering (MALS) technique, together with transmission electron microscopy (TEM), applied to fibre residues from digested autopsy lung tissue
• Who was studied: 311 autopsy lung tissue specimens from 80 subjects in Finland. Some had been exposed at work or in their surroundings to dust from the Paakkila anthophyllite mine. Detailed TEM data were reported for three Paakkila employees and a three-year-old girl, with four lung lobes each. Dates of death and specimen collection are not given.
• Exposure: Anthophyllite fibres from the Paakkila mine in Finland, through occupational or environmental exposure to airborne dust from the mine. All fibres examined by energy dispersive X-ray analysis in a sample of the residues were anthophyllite.
• Main results:
  • In the three Paakkila employees and the child, the data showed no regular pattern of fibre distribution among the four lung lobes in mass concentration, number concentration, median diameter or median length.
  • Of the 12 subjects with the highest fibre mass concentrations, four Paakkila employees ranked highest.
  • Fibres in the lung residues differed little in diameter from airborne fibres in the Paakkila mill.
  • Fibres in the lung residues differed markedly in length from fibres in the mill.
  • Of the 80 subjects, the three-year-old girl had the highest median fibre diameter and median length. The author conjectured that her father's working clothes were the source of the large fibres.
  • The highest ultimate fibre diameter (the thickest fibre found in a residue) for the child was 3.76 micrometres. The corresponding figure for the adults is cut off in the scanned text.
  • For the adults, the fibres found fitted a size limit implying that a 2-micrometre-diameter fibre was respirable if shorter than 25 micrometres, while a 1-micrometre fibre could be 100 micrometres long. For the child, the limit implied that a 100-micrometre-long fibre could have a diameter up to 1.73 micrometres.
• The authors' conclusion: The author concluded that the three-year-old girl had fibre concentrations similar to those of the most severely exposed adults and appreciably longer fibres than the adults. Taken with evidence that long fibres are more toxic and carcinogenic, this suggested that childhood exposure to fibres could be particularly dangerous.
• Limitations the authors state:
  • Only a small number of subjects had lung residues suitable for TEM analysis, so the diameters and lengths found for the largest respirable fibres must be regarded as minimum values.
  • Only a fraction of the lung residues contained enough fibre for complete TEM size measurements.

Topics

Medical terms in this study, explained in our Lexicon: Autopsy, Anthophyllite, Transmission Electron Microscopy (TEM).

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