X-Message-Number: 8299
Date: Mon, 9 Jun 1997 08:29:01 -0700 (PDT)
From: Doug Skrecky <>
Subject: interesting bit on fractures 

   The incidence of fractures in cryopreserved arteries has been found
to be sensitive to the rewarming rate. Arteries cooled at 1 C/min to
-80 C, then cooled rapidly by transfer to nitrogen gas at -180 C had a
zero fracture rate when warmed slowly to -100 C, before being placed in
37 C water. When this transfer occurred at -120 C the fracture rate was
35%. When the transfer occurred at -140 C the fracture rate was further
increased to 89%. This rewarming rate dependance of fracturing has been
ascribed to the glass transition of -123 C of the DMSO cryoprotectant
which was used making the arteries very fragile at this temperature.
After slow warming to -100 C had softened the glass, fractures do not
occur regardless of the rewarming rate.

Reference: "Fractures in Cryopreserved Elastic Arteries"
           Cryobiology 34: 183-192 1997

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