X-Message-Number: 9543
Date: Fri, 24 Apr 1998 05:00:18 -0700 (PDT)
From: Doug Skrecky <>
Subject: temperature and permeability

Authors
  Paynter SJ.  Fuller BJ.  Shaw RW.
Institution
  Department of Obstetrics and Gynaecology, University of Wales College of
  Medicine, Heath Park, Cardiff, United Kingdom.
Title
  Temperature dependence of mature mouse oocyte membrane permeabilities in the
  presence of cryoprotectant.
Source
  Cryobiology.  34(2):122-30, 1997 Mar.
Abstract
  Knowledge of cell membrane permeability characteristics facilitates the
  design of cryopreservation protocols which minimize damage from osmotic
  stress and reduce the incidence of intracellular freezing. Such permeability
  characteristics can be determined for oocytes from volume measurements taken
  during exposure to cryoprotectant. Individual mouse oocytes were held using
  negative pressure applied to the zona pellucida by means of a micropipet.
  Each oocyte was perfused with 1 ml 1.5 mol liter-1 dimethyl sulfoxide (Me2SO)
  or propane-1,2-diol at 30, 23, or 10 degrees C. The osmotic response of each
  oocyte before, during, and after perfusion was recorded by videomicroscopy
  until equilibrium was reached. Mean cell diameter across three axes was used
  to calculate oocyte volume, assuming sphericity, and, using mathematical
  modeling, values for hydraulic conductivity (Lp) were found to be 0.64, 0.41,
  and 0.20 micron min-1 atm-1 in the presence of Me2SO and 0.53, 0.36 and 0.15
  in the presence of propane-1,2-diol at 30, 23, and 10 degrees C,
  respectively. Cryoprotectant permeability (omega) was 0.37, 0.16, and 0.035
  for Me2SO and 0.43, 0.24, and 0.04 for propane-1,2-diol, while the reflection
  coefficient was 0.98, 0.94, and 0.99 (Me2SO) and 0.76, 0.99, and 0.95
  (propane-1,2-diol) all at 30, 23, and 10, respectively. The corresponding
  activation energies (Ea) were 11.65 and 12.23 kCal mol-1 for Lp and 23.52 and
  22.48 kCal mol-1 for omega, in the presence of Me2SO and propane-1,2-diol,
  respectively. Values generated for Lp and associated Ea were similar to those
  found for mouse oocytes in the absence of cryoprotectant, while omega and its
  Ea were similar to those found for oocytes of other species.

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