Comments on Dodson et al., A technical comparison of evaluating asbestos concentration by phase contrast microscopy (PCM), scanning electron microscopy (SEM), and analytical transmission electron microscopy (ATEM) as illustrated from data generated from a case report

Our plain-English summary of Comments on Dodson et al., A technical comparison of evaluating asbestos concentration by phase contrast microscopy (PCM), scanning electron microscopy (SEM), and analytical transmission electron microscopy (ATEM) as illustrated from data generated from a case report, by V.L. Roggli, T.A. Sporn, K.J. Butnor (Inhalation Toxicology, 2008).

The study

• Authors: V.L. Roggli, T.A. Sporn, K.J. Butnor
• Journal: Inhalation Toxicology
• Published: 2008;20(12):1113-4; author reply 1115-7
• Type of article: Comment, Letter
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This is a letter to the editor, not a new study. The authors responded to a 2008 article by Dodson and colleagues that used one case to compare ways of measuring asbestos in lung tissue, including scanning electron microscopy (SEM) and analytical transmission electron microscopy (ATEM). The letter writers had analyzed the same case in their own 2003 publication. They disputed Dodson's claim that ATEM found elevated chrysotile that SEM missed. They wrote that their earlier analysis had found elevated levels of both amosite and chrysotile in that case. They argued that what matters is how a person's fiber levels compare with an unexposed reference group measured by the same laboratory. They also cited other studies on the biases of each method, and animal studies that did not show disease effects for fibers shorter than five microns. Drawing on 10 published and five unpublished cases, they stated that among mesothelioma patients whose only recognized asbestos exposure was to friction products, increased chrysotile was invariably accompanied by increased commercial amphiboles (amosite or crocidolite). The authors concluded that this casts serious doubt on claims that the chrysotile in such patients came from friction products.

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: Letter to the editor commenting on a published article (Dodson et al., 2008). It presents no new study data.
• Who was studied: The letter comments on the Summary section of Dodson et al. (2008), a case report. That case was also 'case 1' in the letter writers' 2003 study of 10 cases. The letter also refers to five further cases the writers had studied since then, which were unpublished.
• Exposure: Asbestos in lung tissue: chrysotile and commercial amphiboles (amosite, crocidolite), in mesothelioma patients whose only recognized asbestos exposure was to friction products.
• Main results:
  • The authors called Dodson et al.'s statement inaccurate. Dodson et al. had said that ATEM at 15,000x found a significantly elevated chrysotile concentration in this case that SEM at 1,000x did not. The authors said their earlier publication had reported elevated amosite and chrysotile in the same case.
  • The authors argued that exact fiber counts differ between laboratories. In their view, what is relevant is comparison with an unexposed reference population analyzed by the same laboratory. On that basis, they said Dodson et al.'s findings were no different from their own.
  • Citing another study (Roberson et al., 1992), the authors stated that ATEM is biased toward detecting chrysotile and SEM toward detecting commercial amphiboles such as amosite.
  • The authors stated that, despite the limitations of both techniques, SEM and ATEM agree notably in fiber burden analyses of mesothelioma patients. They supported this by citing other studies, including Dodson et al. 2005 and their own analysis of more than 400 cases.
  • The authors disputed Dodson et al.'s concern about short fibers. They cited animal inhalation studies by Davis and colleagues that did not show disease-causing effects for fibers under five microns in length.
  • Based on their 10 published cases and five additional unpublished cases, the authors stated the following. Among mesothelioma patients whose only recognized asbestos exposure was to friction products, an increased chrysotile level was invariably associated with increased commercial amphiboles (amosite or crocidolite).
• The authors' conclusion: The authors noted that commercial amphiboles have not been used in friction products in the USA. They concluded that their findings cast serious doubt on claims that increased chrysotile in such patients came from friction products.

Topics

Medical terms in this study, explained in our Lexicon: phase contrast microscopy (PCM), Scanning Electron Microscopy (SEM), Analytical Transmission Electron Microscopy (ATEM).

Related studies

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