X-Message-Number: 7504
From: Brian Wowk <>
Date: Wed, 15 Jan 1997 00:04:37 -0600
Subject: Visser method media report

Trygve Bauge <> writes on CryoNet:

>On the 14th of May 1996 the Norwegian newspaper Dagbladet carried the
>following article:
>
>(In translation:)
>Medical doctors at the Pretoria University in South Africa have found
>a new chemical mixture that enables the cryonic preservation of hearts,
>kidneys and livers. The organs can later be thawed and used as
>transplants.

	This is the "Visser method" that CI and Alcor are studying 
to adapt for use in cryonics.  Unfortunately these media reports
are simply not true (as best as we can determine).  There have been
no successful transplant results for any of these organs in any
animal model.  Moreover, the putative Visser agent, dimethylformamide 
(DMF) appears to be highly toxic to kidneys at 40% v/v concentration
(which is well below the minimum 52% concentration needed to vitrify).
While DMF has reduced toxicity at lower concentrations, such as 25%,  
the quantities of ice that form with such concentrations are fatal to
kidneys.  So claims of perfected kidney preservation appear
particularly implausible.

	The most remarkable achievement of the Visser method
to date is the recovery of a beating rat heart on a Langendorf
column following rapid cooling in liquid nitrogen.  Whether
this method (given the large quantities of ice that form in
slowly cooled non-toxic DMF solutions) will be extendable 
to a transplant model with long-term survival remains an open
question. 
    
***************************************************************************
Brian Wowk          CryoCare Foundation               1-800-TOP-CARE
President           Human Cryopreservation Services   
   http://www.cryocare.org/cryocare/

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