[Histonet] Atherosclerosis and freshly cut tissue

[Douglas A Gregg]

I would suggest that in future studies to try PLP fixative
(paraformaldehyde-lysine-periodate). I have had good experience with a
number of antigens that I have been able to preserve in wet tissue for
years. I work mainly with viruses. About half of the viral antigens tried
could be preserved for years. The other could only stand a few days to a
couple of weeks in fixative before losing their antigenicity. Retrieval
is needed in almost every case but staining can be as good as fresh
tissue even years later. Formalin fixed tissue usually failed completely
after a year even with the most robust antigens. PLP will turn yellow and
stain the tissues yellow to some extent after a few weeks or months, but
don't worry about it. This does not seem to affect the immunostaining.  I
might add that with some antigens it works better to leave the tissue in
the wet PLP until needed and then embed what you need to cut shortly
before immunostaining. I have lost staining in paraffin blocks in as
little as one month when the wet tissue re-embedded was fine. My record
is 12 years. 

Best of Luck,
Douglas Gregg
Veterinary Pathologist
Plum Island Animal Disease Center
Greenport,k NY 11944