Re: Cow ears

From:Gayle Callis

You did not say how large the specimens are?  with a conventional microtome
or a larger microtome for huge sections?  

Two things that may help. Look at your processing schedule, and also the
type of paraffin you use.  You may have to extend processing schedule just
because of the dense nature of cow ear! Hopefully you have vacuum/pressure
capabilities, for longer dehydration/clearing/infiltration with harder
paraffin, ie Tissue Prep 2, embed in same paraffin. Also, if you use 1
change of xylene, then one change of Clearite 3 or Propar, OR two of the
latter clearants, you may get better sectioning.  These are less hardening
to tissue and use ambient temperatures for processing to get rid of extra
heat that tends to dry out leaner animal tissues.  Harder paraffin gives
more support and cuts nicely, we use it for decalcified bone samples and
dense tissues. If you do not want to infiltrate with TP2, infiltrate with
your regular paraffin and embed in Tissue Prep 2 for extra support around
ear. There are other equivalent paraffins on the market, hopefully vendors
will come forth.  

After trimming block, soak it on an ice block covered with ice water for 15
min or so.  You can even use warm water, then go to cold ice water to make
sure the specimen is as firm as possible for sectioning.   

Second:  use high profile disposable blade, rather than low profile, they
are sturdier due to bit more thickness and width, this helps prevent any
instability and they are just as sharp as low profile blades.   Disposable
blades we prefer for decalcified bone and tough tissues, ie cow ears, are
DuraEdge (Statpath has these), Richard Allan Edge Rite, Sakura Finetek
Accuedge, and Olympus teflon coated blades.  

 At 09:23 AM 7/26/02 -0400, you wrote:
>Hi all!
>Can anyone give me some helpful suggestions for sectioning cow ears?
>Frankly, they cut like leather!
>Jeanine Bartlett, HT(ASCP)
>Centers for Disease Control
>Infectious Disease Pathology Activity
>1600 Clifton Rd., N.E.  MS-G32
>Atlanta, GA  30333 
Gayle Callis
Research Histopathology Supervisor
Veterinary Molecular Biology - Marsh Lab
Montana State University - Bozeman
19th and Lincoln St
Bozeman MT 59717-3610

406 994-6367 (lab with voice mail)
406 994-4303 (FAX)


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