[Histonet] Asbestos fibres in tissues
I know you gave already had several replies to your question, but I
would like to add my 2 cents worth.
Several years ago while I was still working in England, I was part of a
major asbestososis-mesothelioma project. I was involved in examining
tissues from several hundred autopsies for asbestos fibres and/or
absbestos bodies. This project was initially sparked by the discovery of
asbestos-associated diseases in elderly females none of whom had ever
been employed in the industries traditionally associated with asbestos.
To cut a long story short, these women, who were mainly housewives, had
been exposed to powdered asbestos while assembling gas-masks during
World War II. The masks were intended to be used in the event of
"poisonous gas" attacks (which never occurred). The exposure to asbestos
was quite brief, sometimes only a couple of weeks working on the
assembly line. But, some 25-30 years later, they presented with
classical asbestos-associated diseases.
We did find patients with large numbers of asbestos fibres, but no
asbestos bodies; patients with few fibres/bodies, but massive
fibrosis/mesothelioma; and patients with large numbers of asbestos
bodies, but little evidence of fibrosis, etc. We also found that
specific types of asbestos were more likely to cause mesothelioma than
other types. Asbestos is a silicate and consequently will polarize
light, however, the fibres can be very fine and easily overlooked by the
inexperienced. After period of time, the ends of the fibres are coated
by an iron-containing protein material, producing the classical
"dumbell" shape. Additional protein-iron material will produce a fully
coated fibre. Coated fibres are no longer birefringent when viewed by
polarized light. The pathologist in charge of the project, Stephen
Phillips Jones, wrote several articles on these topics, and went on the
become on of Europe's most respected asbestosis experts.
As part of the project, we used a variety of procedures to find the most
effective/efficient means of identifying the presence of asbestos fibres
or bodies. The procedures we finally settled on require both fresh and
fixed autopsy tissues. The procedure we used for fresh tissues is as
Slice through a large portion of lung tissue (we routinely used the left
lower lobe) to expose the parenchyma. Squeeze the tissues very firmly to
extract the tissue fluids, using a funnel to collect the "juices" into a
large plastic centrifuge tube is most convenient. This is a messy,
bloody, seemingly crude procedure, but it works very well. Add a lysing
reagent to the "juices" to get rid of the red cells, I believe we used
saponin, but any lysing agent will work. Centrifuge the tissue fluid,
discard most of the supernatent and make wet preparations from the
concentrate. No staining is required. Asbestos bodies, if present, are
very conspicuous and easily identified. Asbestos fibres, much finer and
easily overlooked, can be identified by the use of polarized light.
The wet preps are not permanent and can be discarded after examination.
The lung tissue must be unfixed. Autolysis and putrefaction do not have
any effect on the asbestos content, although they make the procedure
For fixed tissues, we used the following procedure. From each processed
block of lung tissue, we cut a 30 micron section. This was dried as
usual, dewaxed, coverslipped, and examined using brightfield and
polarized light microscopy. Asbestos fibres or bodies were easily
identified.The section does not require staining.
As other Histonet members have commented, asbestos bodies are strongly
Perls' Prussian blue positive due to the ferric iron present in the
coating. However, the morphology of the asbestos body is unmistakable
and does not really require confirmation by special stains.
Some texts have recommended using microincineration to "cremate" the
cellular tissue components and leave a residue of asbestos-containing
ash that can be examined. We tried this method, but found it to be
unreliable, time-consuming and generally a pain in the %$#.
Hope these thoughts help, if you need any more suggestions, let me know.
Sorry for the late response, but I was down in Florida for the past
three weeks enjoying the beautiful weather, beaches, and scenery of the
Kamloops, BC, Canada
Fred Underwood wrote:
> I asked this question earlier, but am not sure it got posted. I'm
>looking for a technic to demonstrate asbestos fibers. Possbily by
>digesting the tissue. Thanks in advance.
>Fred Underwood HT(ASCP)
>Montgomery County Coroner
>Histonet mailing list
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