RE: [Histonet] RE: Tissue fixation help

From:Rene J Buesa

Sometimes the pathologists give a diagnosis on a frozen section "pending" of a definitive diagnosis when "permanent sections" (i.e. paraffin sections are done). In our laboratory it was routine to process what was left of the tissue used for the frozen section and one of the elements to take into consideration was the size and shape of the paraffin sections vs. that of the frozen section. In our laboratory we routinely obtained a reduction in size of the order of 20 to 25% (sometimes a little more or a little less, depending on the nature of the tissue: the harder it was, the less shrinkage).
Rene J.

"Rittman, Barry R"  wrote:
Several reasons
Perhaps the major one is that frozen and paraffin sections of equal
thickness show a different morphology. Frozen tissue is said to have a
general shrinkage of soft tissues of around 2-5% while in paraffin this
may reach 25 -30%. Sections of equal thickness therefore contain
different volumes of tissue and will stain to different degrees. The
final image therefore does not always allow for easy comparison.

-----Original Message-----
[] On Behalf Of Charles
Sent: Monday, October 03, 2005 2:54 PM
To: Patsy Ruegg; C.M. van der Loos;
Subject: RE: [Histonet] RE: Tissue fixation help

Just very curious. Why would anybody paraffin embed after the tissue
had already been frozen? Either way gets it hard enough to cut, which is
the purpose of both procedures.

Charles W. Scouten, Ph.D. 
5918 Evergreen Blvd. 
St. Louis, MO 63134 
Ph: 314 522 0300 x 342
FAX 314 522 0377 

-----Original Message-----
[] On Behalf Of Patsy
Sent: Monday, October 03, 2005 2:46 PM
To: 'C.M. van der Loos';
Subject: RE: [Histonet] RE: Tissue fixation help

I too have thawed tissue in rt formalin and then processed and embedded
in paraffin which good morphology and IHC results (haven't tried with
antibodies to phosphorylated sites but other IHC has been fine, it all
depends on if the samples was properly frozen in the first place) I
tried to do this with some heart tissue which had just been placed in a
-80dc freezer with out snap freezing in OCT and it was awful, but the
frozen section was bad as well.

Patsy Ruegg, HT(ASCP)QIHC
IHCtech, LLC
Fitzsimmons BioScience Park
12635 Montview Blvd. Suite 216
Aurora, CO 80010
wk email
web site

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-----Original Message-----
[] On Behalf Of C.M. van
der Loos
Sent: Sunday, October 02, 2005 11:43 PM
Subject: [Histonet] RE: Tissue fixation help


Long time ago we thawed a frozen tissue sample directly in
temp.) NBF (24-48 hs). Morphology was kept surprisingly well.
at that time phosphorylated antibodies were not even existant....

Chris van der Loos, PhD
Dept. of Pathology
Academic Medical Center M2-230
Meibergdreef 9
NL-1105 AZ Amsterdam
The Netherlands

phone: +31 20 5665631

Date: Fri, 30 Sep 2005 08:25:24 -0400
From: Angela McNabola 
Subject: [Histonet] Tissue fixation help
To: [1]
Good Morning,
Does anybody on the histonet have any experience with taking
that has
been snap frozen in minus 80, and then "thawed" out and formalin
paraffin embedded?
I won't get into the reasons why we have to do this, but does
have a
protocol (or just slowly thaw it out and fix it??). How did your
turn out,
especially when using phosphorlyated antibodies? Did you get
morphology of
your tissue?
thanks in advance!
Angela McNabola, MS HT(ASCP)SLS, QIHC
Bayer Healthcare
400 Morgan Lane
West Haven, CT 06516


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