Hello,
Someone I know is having major issues and I need your help. The problem is
as follows:
She is running  IHC on paraffin embedded tissue(mouse/human xenograph),
Rabbit polyclonal VEGF.
The assay was working fine three months ago with the same reagents and the
exact same tissue. At the time she used Citra Ag retrieval for 5 min., and
proceeded with basic IHC.
Now, the only way she can get a signal is by using Tris/EDTA(pH10)
pretreatment boil/simmer/steam(she's tried it all) for 10-15 min. This is
okay for small sections, but she needs to do larger sections which encompass
multiple organs(kidney,intestine,spleen). These larger sections come right
off the slide. Thus, she is stuck between no signal and the tissue coming
off the slide. She has used positive slides, silane adhesive...all of the
usual tricks. I have asked everyone else I know and have run the full gambit
of tricks.

Help,
Matthew