Hi Greg,
For any that have ISH staining, we add to the protocol that fixation should be
24-32h. Tissues are transferred to 70% EtOH after that. One thing to note is
that for brain tissue, it should not be in 70% for longer than 24 hours,
because tissue artifacts (vacuolization) will occur.
Background:
I read on a vendor website that tissues stained using In situ hybridization
should not exceed 32 hours fixation. Greater than 32 hours can produce
false negative results because the validated retrieving protocol can be
inadequate.
We in fact have seen evidence of this in our lab
