Discussion Summary - Webster

Our plain-English summary of Discussion Summary - Webster, by I. Webster (1973).

The study

• Author: I. Webster
• Published: BIOLOGICAL EFFECTS OF ASBESTOS (J.C. WAGNER, EDITOR), LYON: IARC SCIENTIFIC PUBLICATIONS, VOLUME 8, PP. 264 (1973)
• 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 one-page item was not a research study. It was the author's written summary of a discussion session in a conference volume on the biological effects of asbestos, and it reported what participants said or presented. An observation by Asheroft (as printed) and Heppleston, that severity of asbestosis was not related to how long asbestos had been in the lung in a small group of cases, was said to possibly show a limit of the idea of exposure duration. Dr Sluis-Cremer presented a survey of South African asbestos cement workers in which 180 of 1400 workers had uncalcified pleural plaques; plaque development was described as dose-response related. Mr Gibbs reported 530 cases of pleural plaques in a survey of 15,000 X-ray plates in Quebec. These appeared related to dust from surrounding rock rather than asbestos fibre and were associated with mining a layer present only at Thetford. Dr Governa reported that chrysotile combined with PHA or BSA reacted with lymphocytes. The author noted there was not enough time to discuss whether plaques play a role in pleural mesothelioma.

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: Discussion summary: the author's written account of a conference discussion session, reporting other participants' presentations and opinions. It contains no study by the author.
• Who was studied: No study population of its own. The participants' reports included South African asbestos cement workers (1400 workers) and a survey of 15,000 X-ray plates in Quebec.
• Exposure: Asbestos in general. Specific reports covered asbestos cement work in South Africa, underground mining and maintenance work in Quebec (Thetford area), and laboratory tests using chrysotile.
• Main results:
  • Reported by Dr Sluis-Cremer: of 1400 South African asbestos cement workers, 180 had uncalcified pleural plaques.
  • Reported in the Sluis-Cremer survey: rheumatoid factor (detected by a test printed as the 'HEA test') was positive in a significant number of employees with plaques. Plaque development was dose-response related but occurred in a particular group of workers, possibly indicating a susceptible population.
  • Reported by Mr Gibbs: 530 cases of pleural plaques were found in a survey of 15,000 X-ray plates in Quebec.
  • In the Gibbs report, the Quebec plaques were associated with mining a layer present only at Thetford.
  • Observation attributed to Asheroft (as printed) and Heppleston: in a small group of asbestosis cases, no relationship was found between the severity of asbestosis and the residence time of asbestos in the lung.
  • Reported by Dr Governa: in laboratory tests, both PHA and BSA combined with chrysotile reacted with lymphocytes. Splenic cells gave a negative reaction.
  • Opinion of Dr Navratil: calcified pleural plaques do not undergo malignant change.
  • Opinion of Dr Mancuso, contrary to evidence given by Davis and Gross: short asbestos fibres contributed to fibrosis but were difficult to measure in air samples.
• The authors' conclusion: The summary gives no overall conclusion of the author's own.
• Limitations the authors state:
  • The author noted that the discussion ran out of time before the possible role of pleural plaques in the development of pleural mesothelioma could be discussed.

Topics

Medical terms in this study, explained in our Lexicon: Asbestos-Cement, Pleural Plaques, Dose-response relationship, Chrysotile, Pleural Mesothelioma.

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