[Histonet] RE: whole mouse brains

[Catherine Simonson]

Yes, it is embedding, not encasing.  That's why you use the longer
processing schedule for larger tissues.  Brains and spines typically
require longer processing schedules than other tissues due to the higher
fat levels because of the myelin.  For whole mouse and rat brains, so long
as they are properly fixed, process on average for about 1.5 hours per
station.  Works like a charm, no issues.  Typical (trimmed in) brain
sections can get by on about 45 minutes per station.  I have even had to
process whole large animal organs, of course this was under a hood and took
several days to complete, but......

And, no, not all animal researchers perfuse.  Quite often, the brain is
removed prior to fixation.  And depending on what is to be done with the
slides after sectioning, frozens are not ideal.  Morphometry may be
altered, etc.  It all depends on the desired end result.

Sincerely,

Catherine Simonson, HT (ASCP)
The Jackson Laboratory
Bar Harbor, ME

On Mon, Apr 13, 2015 at 10:19 AM, Scouten, Charles <
Charles.Scouten <@t> leicabiosystems.com> wrote:

> Are you really embedding, or just encasing?  I have heard that paraffin
> cannot penetrate that deeply, that small sections are necessary for the
> paraffin to infiltrate the entire piece.  Is this not true?
>
> Why not use frozen sections?  You can encase the brain in premade gelatin
> molds see this link:
>
> http://www.leicabiosystems.com/research/neuroscience/tissue-sectioning/details/product/leica-brain-blocker-one/
> and section gelatin and all.  Every brain in the same plane of section.
>
> Do you use fixation perfusion, or just extract the soft brain?  Animal
> researchers routinely use perfusion for the better tissue quality.
>
> Cordially,
>
> Charles W. Scouten, Ph.D.
> Applications Specialist
> Leica Biosystems
> Charles.Scouten <@t> Leicabiosystems.com
> http://www.myneurolab.com
> Ph.  630 964 0501
> Cell  314 724 5920
>
>
> -----Original Message-----
> From: histonet-bounces <@t> lists.utsouthwestern.edu [mailto:
> histonet-bounces <@t> lists.utsouthwestern.edu] On Behalf Of Catherine Simonson
> Sent: Friday, April 10, 2015 12:38 PM
> To: histonet <@t> lists.utsouthwestern.edu
> Subject: [Histonet] RE: whole mouse brains
>
> Hey there!
>
> I embed whole mouse brains on a regular basis.  First, process on a longer
> schedule (about 1 to 1.5 hours per station, really.  Otherwise they are
> under processed and will not cut well and you will have problems getting
> them to stay on the slides during staining).  Use the deep molds.  Keep in
> mind that the tissue will shrink (about 20 - 30 %) during processing so
> they WILL fit for coronal sections.  If need be, trim some of the olfactory
> bulbs off (you probably would be facing those off on the microtome anyhow).
>
> Hope this helps,
>
> Catherine Simonson, HT (ASCP)
> The Jackson Laboratory
> Bar Harbor, ME
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