X-Message-Number: 23175
From: "Basie" <>
Subject: Ambiguity about cryoprotectants
Date: Sun, 28 Dec 2003 00:12:46 -0500

"Although it is certain that glycerol can exert an important cryoprotectant
influence on many insects, there still exists a certain ambiguity as to its
precise role. Looking at some data on the point, we find examples of three
cases: In one case, for example the lepidopteran mentioned earlier, Monema
flavescens, the prepupae accumulate glycerol (to about 5% of fresh weight)
and gain protection from freezing. In a second case, insects accumulate
glycerol, but they do not gain protection. This occurs in extreme cases in
some species. For example, larvae of the beetle Dendroctanus manticolae
accumulate up to 23% of fresh body weight in glycerol and gain no protection
from freezing. In a third case, insects do not accumulate glycerol, but they
are able to tolerate very cold ambient temperatures. Larvae of the
lepidopteran Hestina japonica, for example, can tolerate freezing to -15 oC
with no increases in body glycerol."

What evidence is there that cryoprotectants at the level used can actually
protect humans?  Maybe one day someone with a lot of money will pay a
laboratory that do this kind of thing to infuse a 1000 mice with different
concentrations of cryoprotectants and see which ones have the least tissue
damage. Such study may even make it into the serious scientific journals.



Basie

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