[Protein-analysis] Re: Formalin-fixation after snap freezing

[Kyle Legate]

RWILLDMD from aol.com wrote:
>  
> My question:  Is it possible to fix the previously frozen samples in  
> formalin and continue analysis via immunohistochemistry for the protein  
> (specifically proinflammatory cytokine) expression?   Also, does minus  20 storage 
> (instead of minus 80) put the tissue at risk?
>  
I'm assuming you plan to section the tissue for IH studies. In this case 
I would embed the tissue, unfixed, directly in cryomatrix, cut in a 
cryotome, and fix them on the slide as you need them with 4% PFA on ice 
for 10-15 minutes. I have not had any problems in the past by storing 
blocks at -20 for a couple of months but it really depends on what 
you're trying to detect. Trial and error is the only way to know.