The use of Soluene and KOH as tissue digestants for the determination of asbestos in tissue

Our plain-English summary of The use of Soluene and KOH as tissue digestants for the determination of asbestos in tissue, by G.R. Grieger, I.M. Stewart (Environmental Health Perspectives, 1976).

The study

• Authors: G.R. Grieger, I.M. Stewart
• Journal: Environmental Health Perspectives
• Published: 1976;18:222-3
• Type of article: Letter
• Read it: PubMed · Publisher · Free full text

In plain English

This was a letter to the editor, not a full research report. While studying rats injected intravenously with a chrysotile suspension, the authors found that their early control samples, from animals not given asbestos, showed no detectable asbestos fibers. Later control samples digested with Soluene showed large amounts, in some cases higher than in similar organs of injected animals. In Soluene-treated control tissue, counts ranged from 0.25 million fibers per gram in heart to 24 million per gram in lung. The same tissue types prepared by low temperature ashing were all below the detection limit. After testing all their solvents and solutions, the authors found asbestos only in the Soluene. The supplier confirmed it had been filtered through an asbestos filter during manufacture. The contamination was variable and unpredictable. The authors concluded that Soluene is not suitable for measuring asbestos in tissue and that such data must be regarded as suspect. They suggested that KOH digestion may also risk contamination. They reported that low temperature ashing gave clean preparations, with good reproducibility on replicate lung samples from an asbestos-injected animal.

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 describing the authors' laboratory experience comparing tissue preparation methods for asbestos fiber counting
• Who was studied: Control (non-injected) rat tissue samples (muscle, lymph nodes, liver, spleen, lung, heart) from an animal study of intravenously introduced asbestos; number of animals and samples not given
• Exposure: In the underlying study, some rats were injected intravenously with a chrysotile suspension. The letter compares two tissue preparation methods for counting asbestos: digestion with Soluene and low temperature ashing in an oxygen plasma.
• Main results:
  • In control rat tissue prepared with Soluene, fibers per gram were: muscle 3 x 10^6, lymph nodes 3.5 x 10^6, liver 1.8 x 10^6, spleen 1.6 x 10^6, lung 24 x 10^6, heart 0.25 x 10^6. All the same tissue types prepared by low temperature ashing were below the detection limit (0.02 to 0.2 x 10^6 fibers per gram).
  • Some Soluene-prepared control samples showed asbestos levels higher than similar organs from animals injected with chrysotile.
  • Of all solvents and solutions tested, only the Soluene contained asbestos. The supplier confirmed it had been filtered through an asbestos filter at one stage of manufacture.
  • The extent of the Soluene contamination was variable and unpredictable.
  • Low temperature ashing gave clean preparations. Replicate samples on aliquots of lung tissue from an asbestos-injected animal showed good reproducibility. No asbestos was seen in similar organs from control animals.
• The authors' conclusion: The authors concluded that Soluene is not suitable as a tissue digestant for determining asbestos in tissue and that data obtained this way must be regarded as suspect. They suggested, based on published data on asbestos in caustic solutions, that KOH digestion also has a potential for contamination.

Related studies

• Determination of mineral fibre in human lung tissue by light microscopy and transmission electron microscopy — A.J. Rogers (1984)
• Detection and determination of chrysotile in talc USP — H.A. Rose (1974)
• A procedure for the isolation of amosite asbestos and ferruginous bodies from lung tissue and sputum — M.G. Williams, R.F. Dodson, et al. (1982)
• A rapid and simple method of extracting asbestos bodies from lung tissue by cytocentrifugation — A. Ehrlich, Y. Suzuki (1987)
• Preparation of extrapulmonary tissues and body fluids for quantitative transmission electron microscope analysis of asbestos and other mineral particle concentrations — P.M. Cook (1979)
• Breath Analysis for Early Detection of Malignant Pleural Mesothelioma: Volatile Organic Compounds (VOCs) Determination and Possible Biochemical Pathways — A. Di Gilio, A. Catino, et al. (2020)

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