Paul wrote:
>I have tissues which were fixed in glutaraldehyde and then embedded in
>paraffin.
>Does anyone have experience in performing IHC on sections processed this way?
>Routine methods (antigen retrieval with citrate buffer etc.) do not seem to
>produce good results.
>The tissue were originally designated for EM.
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Dear Paul,
The only way to get results on your glutaraldehyde fixed tissue is change
to another, glutaraldehyde compatible antibody directed against the antigen
of interest. When such an antibody  is not available you have to start with
fresh tissue all over again. When above mentioned options are not possible,
the following treatments might be of use:
- when applicable: removing osmiumtetroxide with 10% hydrogenperoxide in
distilled water. Keep your section in this solution until the black osmium
contrast has dissapeared.
- treatment of section with 0.1% sodiumborohydrid in PBS for 15 minutes.
Sodiumborohydrid might unmask the antigen because it reduces double bonds
(a.o. those introduced by glutaraldehyde fixation). This has only an effect
when the epitope is not chemically changed by the glutaraldehyde.
- similar effect can be obtained by enzymatic treatment, e.g., trypsin
Hope this is of help, Peter

========================================
Peter van de Plas
AURION
Costerweg 5
6702 AA Wageningen
The Netherlands
phone: (31)-317-497676
fax: (31)-317-415955
http://www.aurion.nl