I was wondering if phosphate buffered saline (PBS) can be used as a temporary 
holding solution for tissue after primary fixation, and how long can the tissue 
remain in PBS?  If not, what is a better holding solution?  Some of our 
researchers after fixation in 4% paraformaldehyde will put the tissue in 70% 
alcohol.  This is overdeyhdrating the tissue by the time we process it, and I 
was wondering if we safely put this tissue in PBS instead. 

Bob Meyer, HTL 
Northwestern University