X-Message-Number: 14819
Date: Wed, 1 Nov 2000 08:24:05 -0800 (PST)
From: Doug Skrecky <>
Subject: glucose injections extend frozen frog survival

Title
  Freeze duration influences
  postfreeze survival in the frog Rana sylvatica.
Source
  Journal of Experimental Zoology.  280(2):197-201, 1998 Feb 1.
Abstract
  Survival, cryoprotection, and the time course for recovery of vital functions
  were studied in autumn-collected juvenile wood frogs (Rana sylvatica)
  following freezing at -1.5 degrees C for various periods. Frogs readily
  tolerated freezing for 3 or 9 d, but only 50% survived a 28-d freezing trial.
  Generally, the postfreeze return of vital functions
  (vascular circulation, pulmonary breathing, righting reflex, jumping reflex)
  occurred later in frogs frozen for longer periods. Augmenting endogenous
  levels of the cryoprotectant glucose (via injections) prior to freezing
  substantially increased freeze endurance, as these frogs had
  excellent survival after remaining frozen for as long as 49 d. The improved
  freeze endurance of glucose-loaded frogs apparently was not
  associated with a reduction in ice content but rather may reflect the greater
  availability of energy substrate needed to support metabolism of frozen
  ischemic tissues.

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