X-Message-Number: 29343
From: "Jordan Sparks" <>
References: <>
Subject: RE: Ice Blockers
Date: Thu, 22 Mar 2007 07:58:57 -0700

Everyone understands what the blood-brain barrier is, right?  In layman's
terms, it just means that the very small capillaries in the brain only allow
certain kinds of molecules to pass through.  So the ice blockers in question
are already very very near to the neurons we are trying to preserve in spite
of the fact that they cannot escape out of the capillaries.  Remember that
the goal of perfusion is to prevent extra cellular ice formation, not
intracellular.  So the perfusate gradually dehydrates the neurons to the
point where the intracellular solution is so concentrated that it will
vitrify when cooled.  The water that was inside the neurons passes easily
across the blood-brain barrier into the capillaries.  At this point, the
only water molecules that are at risk of forming ice are in the capillaries.
The ice blockers can do their job there just fine.  At least that's my
rudimentary understanding of the issues.

Jordan Sparks

-----Original Message-----

Is it true that 21CM's ice blockers don't cross the blood-brain barrier?  If
so, then how can they be useful?

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