Subject: RE: Processing Fatty Tissues To: HistoNet 


The major problem with processing fatty tissues, assuming that they are
fixed properly, is that Ethanol is not a good solvent for fat and therefore
cannot penetrate the tissues completely, so the tissues are inadequately
dehydrated.
We have had some success with lipomas by adding a "degreasing" step of
xylene into the processing schedule.
70% ethanol
80% ethanol
90% ethanol
95% ethanol
Absolute ethanol
Xylene
Absolute ethanol
Xylene
Xylene
Paraffin
Paraffin
Paraffin
The first Absolute ethanol will dehydrate the tissue to some extent. The
next Xylene step will remove most of the fat and then the second Absolute
ethanol can complete the dehydration.
A compromise situation that we use routinely is to have
Absolute ethanol
50:50 Absolute ethanol:Xylene
Xylene
This is not quite as effective but it is less disruptive to the normal
schedule and handles moderately fatty tissues.
Laurie Reilly
Histopathology Phone 077 81 4468
Australian Institute of Tropical
Veterinary and Animal Science Fax 077 81 5558
James Cook University
Townsville. 4811
Australia.



At 01:18 PM 05/10/04 -0700, Bliss, Mary E. wrote:
>Hi All,
>
>
>
>How do other laboratorians  prepare fatty breast specimens for
>histology?  Are you doing anything special?  We had a case today which
>our doctor needs to have re-processed.  It appears unfixed, although it
>sat in formalin on the processor over the weekend before it processed on
>Sunday night.   The sections are large (too large in my opinion) and not
>adequately removed of fat. We are using toluene on our processors and
>have considered going to Xylene.  We have tried Penn fixx in the past,
>but discontinued using it years ago.  I know it is a complicated
>subject, but just thought I would see if anyone has any bits of wisdom.
>
>
>
>
>
>Mary E. Bliss
>
>Lead Histologist
>
>Northwest Pathology, P.S.
>
>3614 Meridian St. Suite 100
>
>Bellingham, WA 98225
>
>(360)734-2800 x601
>
>(360)734-3818 FAX
>
>
>
>
>
>_______________________________________________
>Histonet mailing list
>Histonet@lists.utsouthwestern.edu
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Mr.Laurie Reilly                                              Ph 07 4781 4468
Physiology & Pharmacology                           Fax  07 4779  1526
Aust.Inst.of Tropical Vet.& Animal Sc.
James Cook University
Townsville  Qld. 
4811                                      laurie.reilly@jcu.edu.au 

Australia.


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