X-Message-Number: 9509
Date: Fri, 17 Apr 1998 11:32:48 -0700 (PDT)
From: Doug Skrecky <>
Subject: glycerol in skin

Authors
  Zieger MA.  Tredget EE.  Sykes BD.  McGann LE.
Institution
  Department of Biology, University of Waterloo, Ontario, Canada.
Title
  Injury and protection in split-thickness skin after very rapid cooling and
  warming.
Source
  Cryobiology.  35(1):53-69, 1997 Aug.
Abstract
  The ability of low glycerol concentrations and high cooling and warming rates
  to optimize the survival of frozen/thawed split-thickness porcine skin was
  investigated. 1H nuclear magnetic resonance spectroscopy was used to measure
  the diffusion kinetics of glycerol in skin at 4, 12, and 22 degrees C.
  Equilibrium concentrations were 44 to 69% of the external bathing medium.
  Rate constants for glycerol diffusion (D/l2) were calculated from the uptake
  data using a plane sheet model and a least squares method and were
  independent of external glycerol concentrations: D/l2 = 3.84 x 10(-4) 8-1 at
  4 degrees C with an activation energy of 11.2 +/- 4.3 kcal/mol. Skin was
  cooled rapidly (-5100 degrees C/min) after different times of glycerol
  permeation at 4 or 22 degrees C, and survival was assessed after warming
  (+5400 degrees C/min) by an oxygen consumption assay. Recovery of aerobic
  activity increased in a concentration-dependent manner, and reached 100%
  after a 10-min exposure to 2 M glycerol at 4 degrees C or 3 min at 22 degrees
  C, for an uptake of 1.1 M glycerol. Light micrographs of freeze-substituted
  skin showed a glycerol-dependent decrease in the nucleation and growth of ice
  in the dermis and epidermis after rapid cooling. A 5-mm exposure to 2 M
  glycerol at 22 degrees C resulted in the elimination of all observable
  epidermal ice, except for extremely small ice crystals (< or = 0.5 micron
  diameter) in the intercellular spaces and in few nuclei, and complete
  preservation of the fibrous structure of dermal collagen bundles. This
  cryoprotective mechanism has the potential to offer complete protection of
  both dermal and viable epidermal targets of freeze/thaw injury and may be
  applicable to other thin, membranous tissues.

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