X-Message-Number: 15463
Date: Sat, 27 Jan 2001 11:05:07 -0800 (PST)
From: Doug Skrecky <>
Subject: PEG and Vitrification: Toxicity

> Message #15454 From: "Henry R. Hirsch" <>
> 
> Doug Skrecky's message #15143 on vitrification and polyethylene glycol 
> (PEG) reminded me of a recent PEG experience. I drank 4 liters (!) of PEG 
> solution to clean out my colon in preparation for a colonoscopy. It was not 
> pleasant, but I survived quite well, as expected.
> 
High molecular (eg: 10,000) PEG is not absorbed from the colon, so
toxicity is not an issue. The same does not apply to low molecular
weight. My flies start dieing when fed PEG 200. There have been cases
where even high weight PEG is absorbed from wounds and caused
toxicity. Absorbed PEG is metabolised to the poison ethylene glycol.
 
> This indicates that PEG at low concentrations is not toxic. PEG is not too 
> different chemically from the widely used automotive antifreeze ethylene 
> glycol, which, at higher concentrations, IS  toxic. Have any experiments 
> been reported other than the one Doug cited that are relevant to 
> application of PEG to perfusates for cryonics?
> 
Cryobiology 29: 585-598 1992
"Critical Cooling Rates for Aqueous Cryoprotectants in the Presence of
Sugars and Polysaccharides"

Short version of the above: PEG 400 leaves other sugars and
polysaccharides in the dust.....

Cryobiology 29: 511-518 1992
"Cryoprotectation of Purified Rat Kidney Transamidinase by Polyethylene
Glycol"

Short version of the above: 0.01% of PEG 4000, 8000 or 10,000 exerts
COMPLETE cryoprotection. 

Cryobiology 29: 87-94 1992
"Freezing Preservation of the Mammalian Cardiac Explant. II Comparing the
Protection Effect of Glycerol and polyethylene Glycol"

Short version of the above: Polyethylene glycol kicks glycerol's butt.
PEG was superior at reducing ice content via dehydration.

Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=15463