X-Message-Number: 14809
From: Brent Thomas <>
Subject: re: Frozen Frogs -- not so interesting after all
Date: Tue, 31 Oct 2000 11:24:04 -0500

Brian Wowk made a connection that I didn't see in the earlier
article...sadly these frogs were not deep frozen but only
lightly frozen -- still a better "whole organism" response than we see in
the larger mammals (i.e. dogs/pigs) but sadly
not quite where we need to be for long term storage without freezer burn.

From: Brent Thomas 
Sent: Tuesday, October 31, 2000 11:19 AM
To: ''
Subject: RE: Frozen Frogs

you know i did wonder about that a bit...

from the article it quotes:

    Soon, Ken Storey of Carleton University will put them in the freezer and
they will
              become curvy, amphibian mounds of ice, hard as rock, with no
heartbeat, no other sign
              of life.

It appears I was mistakenly equating "hard as rock" with "frozen solid" (ie
deep frozen) but thats kind of why
i posted it to the group...for comment and explanation.

still i do wonder if the "endogenous cryoprotectants" might still provide
functional protection than applied cryoprotectants (which was the basic
thrust of my comment on the story).

thanks for the comment!

-----Original Message-----
From: Brian Wowk [mailto:]
Sent: Tuesday, October 31, 2000 11:22 AM
Subject: Frozen Frogs

Dear Mr. Thomas,

	Re your CryoNet message today: Ken Storey's frogs
are not "frozen solid".  They are at temperatures only a few
degrees below 0'C.  Much of the water in these animals
remains in the liquid state (its freezing point having been
depressed by endogenous cryoprotectants).  Chemistry
still goes on at these temperatures, and these frogs cannot
survive indefinitely in this state.  If you cooled them to a
temperature at which chemistry truly stops (below -100'C)
they would most certainly die.

	It's a bit of a stretch to argue that Frog's protective
strategies will be useful for achieving anything other than
perhaps extended *short term* preservation of organs.
Long-term preservation of complex organs cannot be
achieved by freezing because the amount of ice that
forms at deep sub-zero temperatures is fundamentally
incompatible with whole organ recovery.

----Brian Wowk

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