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/ Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=7504