X-Message-Number: 2618
From:   (Sam Ralph)
Newsgroups: sci.cryonics
Subject: Re: Problem with Cryonics
Date: 19 Feb 1994 21:06:28 GMT
Message-ID: <2k5v0k$>
References: <> <>

Personally, I've never heard of freezing a dog or horse solid - and 
expect it to live. However, smaller animals like frogs and caterpillars 
can be frozen - often for weeks - and do just fine. These animals have 
two approaches, freeze solid or create some antifreeze. This isn't as 
silly as it sounds. Some caterpillars can have up to 40% of their blood 
volume present a small polyhydroxyalcohols. (like the stuff in your 
radiator). This amounts to when the mercury dips, they simply don't 
freeze. Frogs like rana sylvatica (sp?) do freeze, but not completely 
solid. Up to 65% of total body water is sequestered as ice. Earlier 
articles were correct in saying that ice doesn't form inside cells (it 
would wreak havoc on intracellular organisation). But rather, ice 
crystals must form outside and grow slowly so they don't damage cell 
membranes. The limit of 65% is imposed because rising osmotic pressure 
can crush membranes if the crystals don't do any damage. These frogs use 
glucose in ridiculously high concentrations to stave off freezing 100% of 
body water. This works for frogs, as for man well, it isn't quite that 
simple. There's also the question of reperfusion injury, but that's a 
whole other story.

  //Sam Ralph <>
  //Biochemistry Dept. 
  //Memorial U of Newfoundland

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