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 Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=23175