X-Message-Number: 20091
From: "michaelprice" <>
References: <>
Subject: Why does cryo-suspension take so long? 
Date: Wed, 18 Sep 2002 00:28:18 +0100

Speed is of the essence in a suspension.  I'm concerned over the length 
of time cryo-perfusion-suspension takes.

The rat hippocampal brain slices (mentioned awhile back) equilibrated
sufficiently for vitrification in just 20 minutes.  

Why does the suspension of a human take so much longer?  How do 
we determine when the perfusion with cryo-protection agent is 

Is the slower vascular delivery of CPA related to the necessity of a
multi-stage ramped perfusion to avoid the osmotic dehydration shock?

Or is it because of poor vascular delivery of glycerol, or whateever CPA 
is used?  Perhaps we should remove the brain from the skull and
dunk it directly into CPA solution for quicker perfusion?  The cortex is
heavily fissured with a large surface area.  With the dura removed 
immersion of the brain in a CPA might ensure rapid perfusion/delivery.  
There's no reason why carotid CPA delivery can't be run in parallel.

I don't know how long it takes to remove a brain from the skull, but they
always seem to do it quickly in B-movies :-)

Michael C Price

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