Re: Rat Brain

From:"John C. Dennis" <>


How was the brain fixed?  Was the animal perfused or was the tissue
dissected out then fixed by immersion?  Except for neonates up to PN15 or
so, I perfuse the animals then dissect out he brains, cut them into left
and right hemishperes, and "post-fix" by immersion overnight.  If the
tissue is dissected out fresh and not blocked into small hunks, then the
fixation will be incomplete.

If the tissue is over processed, i.e. run too long in the infiltrattion
solutions, especially in the xylene (or substitues) and paraffin steps, it
becomes brittle (?) and you see venetian blind effect and
other symptoms of overprocessing including having your sections come

Perhaps you can ask the folks who processed the tissue.  At all events,
good luck.

John Carroll Dennis
Anatomy, Physiology, and Pharmacology
109 Greene Hall
Auburn University, AL  36849

On Tue, 5 Jun 2001, Louise Strande wrote:

> Dear Histonetters:
> A friend brought me a block of rat brain to cut.  (I have never cut
> brain tissue before).  The tissue had been formalin fixed and paraffin
> embedded.  When I tried to cut it, the tissue just crumbled out of the
> block.  If I used moist heat and then chilled the block, I could get a
> small ribbon,(six or seven sections) but then the tissue  would
> crumble.  I'm not sure it was processed properly.  Does anyone have a
> good protocol for fixing and processing rat brain?  Also, my friend
> would like to cut thick sections (from 40 to 100 microns thick)  What do
> I need to do that?  Any help would be appreciated.
> Louise Strande
> UMDNJ, Camden NJ

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