Chris said it perfectly!  

Additional info: If one wants to do enzyme histochemistry, this is the best
way to preserve most enzymes, which can be inactivated by heat of
processing or fixation

Many people complain about speed, but I can do frozen sections faster than
paraffin for immunohistochmistry, I do not have to wait while they fix,
then be processed, sectioning, rehydration, then some type of retrieval and
incubation of antibody. 

AND my murine CD markers (most commonly worked with here) just plain don't
work with NBF paraffin embedded tissue (FFPE)

I used to dislike frozens, and now prefer them to FFPE tissue by
simplifying much of what I do. 

A word to the wise, from Chris's last statement, you can save yourself a
lot of work IF you check antibody mfr specifications in order to know
whether frozen sections or paraffin is used.  Mfr's give info, although
some people successfully and with a great deal of work, test Ab on paraffin
embedded tissues.  Many antibodies are optimized on frozen sections by mfr
and NOT FFPE.

  

 

>From: "C.M. vander Loos" <c.m.vanderloos@amc.uva.nl>
>Subject: Re: Frozen Sections?
>To: Anila Syed <syedab@totalise.co.uk>

>>Hi Histonetters one and all,
>>
>>Can I ask a stupid question pls?
>>Thanks,
>>
>>I am confused as to the reasons why one would perform frozen section ihc
>>rather than wax embed the material, as it seems rather more
>>hassle to go through to work with the low temperatures etc.
>>
>>
>>Can some kind sole give me the low down on the pros and cons.
>>Many Thanks!!
>>
>>Anila
>
>************
>
>Hi Anila,
>
>Let me try to summarize some pros and cons.
>
>FORMALIN-FIXED AND PARAFFIN-EMBEDDED:
>- long time cheap storage at RT of tissue blocks (as you can keep them
>safely away of bugs and other creatures...)
>- superior tissue morphology
>- epitopes/antigens can be destroyed during fixation and/or embedding
procedure
>- possibility of tissue pretreatments in case of lost epitopes/antigens
>- tissue block-fixation will prevent the loss of soluble antigens
>
>FRESH FROZEN TISSUE BLOCKS:
>- laborious and expensive storage at -80°C
>- rather poor tissue morphology (depending on the tissue fixative used)
>- epitopes/antigens are optimally preserved (depending on the tissue
>fixative used)
>- tissue pretreatments not needed
>- soluble antigens might be lost or reallocated during fixation and/or
>staining steps
>  (option: PFA pre-fixation of small tissue samples > cryoprotection with
>sucrose > freezing > cryosectioning)
>
>(Any additions or comments, Histofolks???)
>
>
>As you see Anila your choice for either paraffin or cryo totally depends on
>what you would like to stain in your sections!!!
>
>Chris
>
>
>
>
>
Gayle Callis
Veterinary Molecular Biology
Montana State University
Bozeman MT 59717-3610
406 994-4705
406 994-4303