Hi,
    Your doctors reluctance was correct. Prefer has a number of detrimental
effects upon immuno stains. My experience has been in imunohistochemistry
(IHC) and not immunoflourescence (IF) with Prefer. (Our IFs are done on
frozens) Many antibodies do not work or leave a lot of background.
    I understand an aversion to formaldehyde, but as I have said before it is
a necessary evil. Antibody manufacturers optimize and product test their
reagents using formalin fixed paraffin embedded tissue or on frozens. They
cannot test every fixative that comes out, nor should they, as standardization
would become impossible. So, like it or not we are stuck with formaldehyde.
Amos Brooks

"P. Emry" wrote:

> Hi all,
>
> I am working with a post doc who wants to inject some "fluorescent
> retrograde neurotracers" in to pigs and use paraformaldehyde to fix the
> specimens. (Forgive me if I have muddled that up.)
>
> He is being very kind in considering my formaldehyde aversions and
> said he would work after I go home.  He is reluctant to use my
> substitute Prefer thinking it may effect the fluorescent signal.
>
> Have any of you worked with Prefer or any other
> formaldehyde-paraformaldehyde substitute for that use?  (I have never used
> paraform. and have no idea how it differs from formaldehyde.)
>
> I am sure he will want some references if possible.
>
> Thanks,
>
> Trisha