[Histonet] Re: Immunohistochemistry fixation

[Robert Richmond]

Katherine Walters, Histology Director, Central Microscopy Research
Facilities, University of Iowa asks:

>>Has anyone has any experience using immunohistochemistry with the following fixation? Polyethylene glycol (PEG) solution:  25% glycol, 10% ethanol (95%), 10% formaldehyde (37%), and 55% distilled water. Specifically if there are any enzymatic reactions that I should avoid/block for/etc. - Thanks for any hints-I am pretty much wed to this fixative.

You may be wed to it, but you may be being two-timed if you are.
Polyethylene glycol (trade name Carbowax, from Dow Chemical) is not a
single substance, but comes in a wide range of molecular weights with
physical state anywhere from a watery liquid to a paraffin-like solid.
See the Wikipedia article.

If you're using a commercial product containing PEG, the manufacturer
may know the answer. If you're compounding it yourself, you may just
have to try the IHC's and see. Any publications should cite the
molecular weight (or Carbowax number) of the PEG in the fixative.

Bob Richmond
Samurai Pathologist
Knoxville TN