X-Message-Number: 12447 From: Thomas Donaldson <> Subject: To Doug Skrecky, about fixation Date: Tue, 21 Sep 1999 23:40:29 +1000 (EST) For Doug Skrecky: Your scientific postings have improved a lot over the last few years. However chemical fixation requires two kinds of experiment, both of which you have not posted (and which may not exist). First, we'd like to know if large organs can be completely fixed, and the damage that may occur during such a process simply because it may take some time. (Yes, some parts of a large organ can certainly be fixed, but do we fix all of it? The use of some fixatives by embalmers doesn't really answer this question). Second, unlike the case of cryobiology, I at least am unaware of ANY case in which an organ or tissue, even if small, has been first fixed and then brought back to life. Failing this, it would help a lot to have at least some more explicit idea as to how a fixed tissue (yes, folks, I'm most interested in brains here!!!) might be revived. This may depend on the particular fixative used --- it should, after all. But even if we have no actual case of a fixed tissue being revived, it would at least help to have some idea as to just how we might proceed to find a way to reverse that fixation. And waving your hands in the general direction of nanotechnology isn't good enough. I'm asking for some more explicit ideas. As an explanation of my question, I'll point out that sometimes fossils will show remarkable preservation of structure, even on a microscopic scale: but that information remains insufficient to revive the fossil. The chemical transformations caused by fixation may destroy information we want to preserve, even if the result looks very like the original tissue. Naturally we hope not, but hope is a fragile handle on the future. Best and long long life, Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=12447