Re: glycol methacrylate sections

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From:"Barry Rittman" <>
To:histology <>
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My personal view is that the viewer should be able to get the information from
the section if it is in the 1-3 micron range. Obviously potential resolution
possible will be less with thicker sections.
I think that too much emphasis is placed on having sections at a specific
When viewing sections of tissue with which you are very familiar, at any
thickness there are certain characteristics that you get used to and so you can
always have a guestimate of thickness and this will be within a reasonable range.
The most important criteria here are that the tissue is the same, the same
individual has prepared the tissue and sections including all aspects of
processing, sectioning and staining.  Having said this  there is still room for
debate about whether you can determine a difference in the half micron range.
This is especially true if the tissue is prepared elsewhere or the staining times
are changed.
If you really wish to determine the thickness why not use a dye for the GMA and
compare the areas around the tissue for intensity of staining either by
densitometry or spectrophotometry? (most of the oil soluble dyes will stain the
methacrylates if incorporated before polymerization).
Barry wrote:

> Would anyone with some fairly extensive GMA (or other plastics) viewing
> experience care to briefly discuss the following?  What is your comfort level
> with being assured of the thickness of the section?  That is, if you are
> looking at a well-processed, well sectioned, well-stained kidney biopsy, how
> confident are you to state that this section is 1.5 microns versus 2.0
> microns thick by microscopic viewing alone.  Note I am not talking about
> cutting one at 1.5 and another at 2.0 and then guessing which might look a
> little thinner.  But what about viewing a single slide and stating with
> confidence that this section is at 1.0 or 1.5 or 2.0 microns?  Where is your
> comfort level for making this assessment?  In addition,  what is your idea of
> slide readability for diagnostic purposes?  If something is requested at 1.0
> to 2.0 microns, is 2.5 microns "too thick" to read?  Obviously this may have
> to do with the specimen and the pathology involved, but how precisely crucial
> do you consider the thickness of the section to within a micron or so of the
> requested value?
> Thanks,
> Ray in Seattle

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