X-Message-Number: 16570 Date: Sun, 17 Jun 2001 19:53:48 -0400 (EDT) From: Ben Best <> Subject: Ice blockers and CI protocol On Sat, 16 Jun 2001, Charles Platt wrote: > As has been stated here, 21CM ice blocker is available for purchase by > any interested party, can be used in conjunction with existing protocol, > and had not been purchased by CI (the last time I checked). I do not believe that CI should include ice blockers in its current protocols -- which use high concentrations of glycerol that will reduce ice formation but not result in vitrification. I have strongly advised CI against the use of ice blockers. To quote from the ice-blocker section of the vitrification essay on my website: "As a cautionary note, it should be mentioned that use of ice-blocker without sufficient cryoprotectant (or rapid-enough cooling) to cause vitrification can result in ice formation that is more damaging than the ice that would have formed at a higher temperature if no ice-blocker had been used. Ice-formation at higher temperature tends to be extracellular -- and dehydrates the cells. At lower temperature osmosis is less active. So if ice-blockers simply result in ice formation at a lower temperature, the ice that forms at those temperatures is more likely to be inside the cells, thus causing greater damage. " For more background, I refer readers to the ice-blocker section of the vitrification essay on my website: http://www.benbest.com/cryonics/vitrify.html -- Ben Best -------------------------------------------- Ben Best () http://www.benbest.com/ Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=16570