X-Message-Number: 9482 Date: Mon, 13 Apr 1998 21:10:17 -0700 (PDT) From: Doug Skrecky <> Subject: optimal cooling rate may be 1 C/hour for kidneys Cryobiology 21: 529-535 1984 "The Effect of Cooling and Warming Rate on Cortical Cell Function Glycerolized Rabbit Kidneys" Abstract: Experiments previously reported (Cryobiology 19: 668 1982) suggested that rabbit kidneys permeated with 2 M glycerol are least damaged during freezing and thawing if they are cooled very slowly (1 C/hr). Using similar techniques of glycerolization, cooling, storage at -80 C, rewarming, and deglycerolization, active cell function in cortical tissue slices prepared from such kidneys has now been studied. Oxygen uptake, tissue K/Na ratio after incubation, and slice/medium PAH ratio after incubation were measured. Kidneys cooled at 3.1 C/min and warmed at 4.2 C/min gave poor results in the previous studies and the lowest levels of cell function in the present experiments. Kidneys cooled at 1 C/hr exhibited degrees of slice function that were dependant on warming rate: warming at 1 C/min was better than warming at either 1 C/hr or 20 C/min. These results refine the previously drawn conclusions, (loc cit) and indicate optimal cooling and warming rates for rabbit kidneys containing 2 M glycerol, in the region of 1 C/hr cooling and 1 C/min warming. These rates are much lower than have hitherto been used by others for any system. Some implications of these findings are discussed. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=9482