Preparation of extrapulmonary tissues and body fluids for quantitative transmission electron microscope analysis of asbestos and other mineral particle concentrations

Our plain-English summary of Preparation of extrapulmonary tissues and body fluids for quantitative transmission electron microscope analysis of asbestos and other mineral particle concentrations, by P.M. Cook (Annals of the New York Academy of Sciences, 1979).

The study

• Author: P.M. Cook
• Journal: Annals of the New York Academy of Sciences
• Published: 1979;330:717-24
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy.

In plain English

This workshop article from a US Environmental Protection Agency laboratory in Duluth, Minnesota, is a methods paper. It described existing ways of preparing tissue for counting asbestos and other mineral particles by transmission electron microscope. It set out requirements for quantitative analysis of tissues outside the lung and body fluids. Using Duluth drinking water amphibole fibers and stated assumptions, the author estimated the carbon extraction method would show about one fiber per 3700 grid squares. Assuming 2 cm3 of tissue were digested or ashed, filtered onto a 25 mm membrane filter and transferred directly to grids, about one fiber per 2.8 grid squares would be seen. The author described a urine preparation procedure. When urine samples with no detectable amphibole fibers were spiked with amphibole fibers, the method underestimated them by 29 percent. Membrane filters were described as usually chrysotile-contaminated, and crocidolite was found in one batch. A separate cited report found amphibole fibers in urine of people drinking the water. The author concluded that preparation techniques must be evaluated to show that particle numbers and characteristics stay unchanged.

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 paper (workshop presentation) reviewing tissue preparation techniques for transmission electron microscope analysis and describing a urine sample preparation procedure, with a spiking test of that procedure
• Who was studied: No defined group of people was counted. The paper used hypothetical calculations for tissues of deceased Duluth, Minnesota residents and urine samples (number not stated) from people with and without ingestion exposure.
• Exposure: Amphibole fibers in the Duluth municipal drinking water, approximately 50 million fibers per liter averaged over 20 years before a filtration plant was established in 1977. The author stated that people drinking the water had no other exposure to these fibers.
• Main results:
  • Hypothetical estimate for Duluth tissue (assumed about 5,000 fibers per gram): with the carbon extraction technique, about one amphibole fiber would be found per 3700 grid squares, which the author called an impossible task.
  • Hypothetical estimate: if 2 cm3 of tissue could be processed by chemical digestion or low temperature ashing and filtered on a 25 mm membrane filter, with grids prepared by direct transfer, about one amphibole fiber would be seen per 2.8 grid squares examined. About 20 fibers, or 56 grid squares, might be needed for good precision.
  • In urine samples with nondetectable amphibole fibers that were spiked with water containing amphibole fibers, the preparation method underestimated amphibole fibers by 29 percent.
  • Comparing low temperature ashed blank filters with carbon-coated blank filter grids indicated that most contaminating fibers sit inside the membrane rather than on its surface.
  • Crocidolite fiber contamination was found in one batch of membrane filters.
  • An attempt to prepare a whole blood sample by low temperature ashing gave insufficient sensitivity because of interfering debris.
  • Cited from a separate report (reference 21, Cook and Olson): urine from people ingesting amphibole fibers in drinking water contained amphibole fibers, and none were found in the urine of people with no history of such exposure.
• The authors' conclusion: The author concluded that tissue preparation techniques must be evaluated for their ability to keep particle numbers and characteristics unchanged from the original tissue. Only then can measured concentrations be related to disease incidence and exposure history.
• Limitations the authors state:
  • Replicate analysis of urine samples had not been attempted, because dividing a sample reduces sensitivity.
  • Hydrogen peroxide treatment of urine did not remove all interfering organic matter.
  • Ashing the membrane filter used in the urine method can introduce chrysotile fiber contamination from the filter itself.
  • Little or no information exists on the size of particle losses during tissue preparation.

Related studies

• Quantitative assessment of inorganic fibrous particulates in dust samples with an analytical transmission electron microscope — F.D. Pooley, N.J. Clark (1979)
• Oxygen incineration and electron microscope x-ray microanalysis of mineral particles in biological tissues — W.J. Henderson, C. Melville-Jones, et al. (1978)
• Determination of mineral fibre in human lung tissue by light microscopy and transmission electron microscopy — A.J. Rogers (1984)
• Quantitative characterization of the mesothelioma-inducing erionite series minerals by transmission electron microscopy and energy dispersive spectroscopy — M. Dogan (2012)
• Rapid and easy method for monitoring oxidative stress markers in body fluids of patients with asbestos or silica-induced lung diseases — K. Syslová, P. Kacer, et al. (2009)
• Current applications of molecular testing on body cavity fluids — D. Pinto, F. Schmitt (2020)

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