Re: [Histonet] theoretical question on fixing and section (formalin and cryosections)

From:Gayle Callis

"Right?"   Not necessarily.  Many people do unfixed bone frozen sections ( 
not fixed nor decalcified) and sectioned using the Tape Transfer Cryojane 
system, Instrumedics.  Some antigens hold up well with formalin fixation 
and decalcification followed by paraffin processing.    It will depend on 
what you want to see.  It is always advisable to use gentle 
decalcification,  buffered formic acid or EDTA,  but there are decalcified 
bone retrieval kits, Biogenex has one, to help counter the effects of 
decalcification.  Doing retrieval on frozen sections is sometimes difficult 
with section loss.

Remember that if an acid decalcifier can compromises the antigen EDTA is a 
good choice, followed by paraffin processing.

There are excellent review publications on the effects of decalcification 
on bone immunohistochemistry.  This is also true of the effects of fixation 
on antigens.  If you fix, decalcify and want to snap freeze, the acid would 
have to be rinsed out of bone, and the decalcified bone would need sucrose 
cryoprotection.  There are methods that fix, decalcify with bone snap 
frozen, for IHC.  Go to J Histochemstry and Cytochemistry, look up Kim 
Kusser as the author.  It is not a SHORT method, time consuming if one has 
to do more rapid diagnositic work.

At 11:22 AM 7/30/2004, you wrote:
>Hello all,
>This question refers to bone tissue.  If you want to do IHC, cryosections
>generally give better results, right?  Does it make sense to fix the tissue
>in 10% formalin, decalcify (say in formic acid), and then "embed" in OCT and
>freeze in dry ice to take cryosections?   It just seems like people do 10%
>formalin and follow that with paraffin embedding..
>Zarana Patel
>Histonet mailing list

Gayle Callis
Research Histopathology Supervisor
Veterinary Molecular Biology
Montana State University - Bozeman
PO Box 173610
Bozeman MT 59717-3610
406 994-6367 (lab with voice mail)
406 994-4303 (FAX)

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