You may have come across the 0.2% figure because years ago French cryobiologist Pierre Boutron defined successful vitrification as less than 0.2% ice formation. So that's the convention we use our own lab (21CM). Tissue that shows less than 0.2% ice formation following cooling and rewarming during DSC (differential scanning calorimeter) measurement we regard as vitrified.
Alcor cannot yet do vitrification for whole bodies, so ice formation in a whole body procedure with 7 Molar glycerol is probably around 20%.
We haven't published on B2C, although I can tell you the toxicity is quite high. We'll soon be switching Alcor to M22, which we have published on. It has a much lower toxicity, and lower viscosity so it can be perfused faster with less exposure time before vitrification.
In response to your earlier question, we don't really know what causes cryoprotectant toxicity. Nobody does (yet). Sometimes, if the toxicity is so bad that structure is affected, you can clearly see the cause of the problems. Usually, though, toxicity occurs in absence of any structural damage. The cause is probably enzyme denaturation, but which ones?
Biochemistry would be an excellent field to study if you want to become a cryobiologist.
The vitrification solution currently used for neuropatients, called B2C, is "hyperstable." That means it's impossible to freeze under any circumstances. If tissue concentration approaches the perfused cryoprotectant concentration, which happens in ideal cases, the percent ice formed will be 0%.
You may have come across the 0.2% figure because years ago French cryobiologist Pierre Boutron defined successful vitrification as less than 0.2% ice formation. So that's the convention we use our own lab (21CM). Tissue that shows less than 0.2% ice formation following cooling and rewarming during DSC (differential scanning calorimeter) measurement we regard as vitrified.
Alcor cannot yet do vitrification for whole bodies, so ice formation in a whole body procedure with 7 Molar glycerol is probably around 20%.
We haven't published on B2C, although I can tell you the toxicity is quite high. We'll soon be switching Alcor to M22, which we have published on. It has a much lower toxicity, and lower viscosity so it can be perfused faster with less exposure time before vitrification.
In response to your earlier question, we don't really know what causes cryoprotectant toxicity. Nobody does (yet). Sometimes, if the toxicity is so bad that structure is affected, you can clearly see the cause of the problems. Usually, though, toxicity occurs in absence of any structural damage. The cause is probably enzyme denaturation, but which ones?
Biochemistry would be an excellent field to study if you want to become a cryobiologist.
Re:Cryonics is REALLY UNDER EStiMAteD
« Reply #2 on: 2004-11-04 01:21:03 »
I think in addition to toxicity issues of the cryopreservation fluid, it is also important to consider immediate to long-term external factors, such as:
--Is the storage facility safe and secure? Is it susceptible to electrical storms, tectonic tremors, or unauthorized human interference?
--Are all the facets of the hardware built to withstand the period of time for which they are to be in use, possibly longer? (Gaskets, metal hoses, etc.)
--Is there an emergency backup system to prevent against premature thaw due to power interruption?
Of course, I'm thinking about a specific incident involving a cryonics facility on the West Coast of the U.S....but it does raise issues. It's like a time capsule thing...how do you guarantee that there will actually be someone who knows exactly what to do to reanimate the preserved specimens? How do you guarantee that they will be able to perform this task with whatever equipment they have at their disposal?
Re:Cryonics is REALLY UNDER EStiMAteD
« Reply #3 on: 2004-11-05 10:25:27 »
At the recent WTA conference in Toronto, Keith Henson asked the audience how many were signed up for cryonics. A decade ago most would have raised their hands. This year there were only a scattered few, maybe 10%. Why aren't new transhumanists signing up?
I'd be interested to hear from eveyone here why they haven't signed up yet. a) Never heard of it b) The technology is impossible c) Don't want to wake up in the future d) Even if successful, it won't be me e) Technology possible, but too unlikely to consider f) Too expensive g) Service not available where I live h) Worried about what other people would think i) Other (please specify)
Of course, I'm thinking about a specific incident involving a cryonics facility on the West Coast of the U.S....but it does raise issues. It's like a time capsule thing...how do you guarantee that there will actually be someone who knows exactly what to do to reanimate the preserved specimens? How do you guarantee that they will be able to perform this task with whatever equipment they have at their disposal?
How do YOU guarantee that there wont be anyone who knows exactly what to do to reanimate the preserved specimens? cmon dude, centuries ago... ppl just dreamt of flyin.. & now we got aeroplanes... same applies to ur case... science is evolving!
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