[Histonet] RE: Histonet Digest, Vol 36, Issue 5

[Pixley, Sarah (pixleysk)]

Dear David Finkelstein:
I apologize for not thinking harder about your problem before I wrote.
You have snap frozen brains, while I am working with paraformaldehyde
fixed brains. Big difference. I am able to take the room temperature (or
fridge temp) brains and coat them with OCT and then freeze both OCT and
brains together. This works fine and cuts fine. We don't really have too
many problems with the brains coming out of the OCT. Occasionally they
do come out, but not often.

So this may perhaps explain the differences. Otherwise, other details
are that we cut at either 14 um or 20 um, and we thaw mount onto slides.
We cut at -20 degrees C.

Another suggestion is to use another embedding matrix. I like the
Shandon Thermo M1 embedding matrix because it doesn't curl as badly as
OCT. But right now we are using OCT because when you make a big block of
it, OCT is easier to cut than the M1.

Sarah Pixley

Message: 2
Date: Sun, 5 Nov 2006 12:10:30 +1100
From: "David Finkelstein" <dfinkelstein <@t> mhri.edu.au>
Subject: [Histonet] embedding multiple snap frozen brains
To: <histonet <@t> lists.utsouthwestern.edu>
Message-ID: <001701c70077$30654580$0300a8c0 <@t> davidfink>
Content-Type: text/plain;	charset="us-ascii"

Dear Stephen Peters  and Sarah Pixley,
I am very interested in your methods on freezing brains.
My question is I have never been able to cut brains that have been
covered with OCT.  How do you do it.???  Suggestions please?

Most histologists I know leave the bit of brain that they want sticking
out
of the OCT.   The OCT is a different hardness to the brain. If cutting
nonfixed brain at -14oc  the OCT is too soft and fixed brains at -25o C
the
OCT is to hard.   It is even harder to get the hardness\temperature
right
for foetal tissue.
The solution has been leave it sticking out of the OCT.
David

Assoc. Professor David Finkelstein,
The Mental Health Research Institute of Victoria,
155 Oak Street, Parkville, Victoria 3052 AUSTRALIA