[Histonet] Re: [freezing rat brain flat on slides] HiDi V36, #23-8

[David A. Wright]

Hi Histonet folks

I just wanted to add that, like Patsy, I freeze brain pieces
onto glass slides and get surfaces so flat that I hardly lose
any tissue when I start cutting - which is nice for
stereological calculations.  

I cut frozen rat brains (divided up in a brain mold) on a
sliding microtome. That means I don't have access to the
freezing unit of a cryostat, and I put the glass slide (or a
square from one) + brain piece on a piece of dry ice in an ice
bucket or styrofoam box.  When frozen (they are sucrose
equilibrated), I put an oval collar of parafilm round the
chunk, fill it with OCT and store all the pieces from 1 brain
on their slide in a 50ml conical in the freezer till I can cut
them.

In addition to the flatness, one of the things I like is that
I can see through the slide (before I freeze it) that I
haven't got any air bubbles in the lateral ventricles (they
are hydrocephalic).  [Any bubbles shrink so much on freezing
it distorts the brain shape.]
 -David
>------------------------------

>Message: 8
>Date: Fri, 17 Nov 2006 10:35:22 -0700
>From: pruegg <@t> ihctech.net
>Subject: RE: [Histonet] freezing brain slices

For Mohs we always froze the tissue on a glass slide so that
it would be flat, just lay the tissue on a slide that is in
the cryostat, add OCT and allow to freeze quickly.  Once
frozen, a touch with the thumb on the slide will allow the
tissue to be released and it can then be attached to a
cryostat chuck with the flat slide side up.  The surface comes
out really flat.
>Patsy
>
--------------------------------------
David A. Wright. PhD
Section of Neurosurgery
University of Chicago