Shrinkage

From:Barry Rittman

I think that you have to be really careful when talking about shrinkage
because of the large numbers of  factors that can affect shrinkage.
Some fixatives shrink and some swell tissues or individual tissue
components.
The fixative may or may not protect tissues in subsequent treatment and
while not eliminating shrinkage in these at least may minimize it.
The dehydrating and "clearing" agent used and the length of time in
these can affect shrinkage. The time and temperature in wax or plastic
also can have an effect.
If you are at all concerned about shrinkage then one way is to divide a
block into two. Get weight and volume measurements for each.
Freeze one half and process the other half as you normally would.
Again measure total volume of each.
Prepare standard sections from each block and stain.
Compare visually and measure the individual components that you are
interested.
Even counting the total nuclei in a field should be a useful comparison
because the paraffin processed tissue will have  a greater number per
unit volume.
When you have done this you should have a reasonable estimate of the
degree of shrinkage of the tissue as a whole and of the areas/components
that you are interested in.
This has to be done for each type of  tissue that you are processing.
Barry





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