X-Message-Number: 12602
Date: Wed, 20 Oct 1999 10:27:45 -0700 (PDT)
From: Doug Skrecky <>
Subject: membrane damage may be a drawback to ethylene glycol

(but I think this can be blocked)
---------- Forwarded message ----------
  Reid TJ.  Esteban G.  Clear M.  Gorogias M.
  Department of Hematology and Vascular Biology, Walter Reed Army Institute of
  Research, Washington, DC 20307-5100, USA. 
  Platelet membrane integrity during storage and activation.
  Transfusion.  39(6):616-24, 1999 Jun.
  BACKGROUND: The platelet cell membrane appears to undergo a lipid-phase
  transition on cooling from 23 degrees C to 4 degrees C. Consequences of this
  phase transition are leakage of cellular material and irreversible cellular
  damage. Whether agents, of known benefit in protecting membranes and proteins
  from cooling and drying injury, could also protect platelets was
  investigated. Leakage of cytosolic components was assessed by measuring the
  release of fluorescein into the surrounding medium. STUDY DESIGN AND METHODS:
  Fresh platelets were suspended in 5 percent dimethyl sulfoxide (DMSO) or in 5
  mM of one the following agents: glucose, trehalose, sucrose, glycerol,
  ethylene glycol, 1,2-propanediol, or
  L-proline. Platelets were loaded with 10 nMfluorescein diacetate (FD),
  chilled at 4 degrees C for 24 hours or frozen at -1 degree C per minute to
  -70 degrees C, warmed rapidly at 37 degrees C, and centrifuged, and the
  supernatant was measured for the presence of fluorescein. The effect of FD on
  platelets was assessed by agglutination with ristocetin, aggregation with
  thrombin and ADP, platelet-induced clot retraction, and expression of
  p-selectin. Platelet function and activation before and after freezing or
  cooling were measured by the same methods. RESULTS: By flow cytometry, 98
  percent of the platelets incorporated FD. The trapped fluorescein resulted in
  neither platelet activation (p = 0.9) nor reduction of platelet function (p =
  0.12-0.94) from that in control platelets. Freezing of platelets in DMSO
  caused far less release of fluorescein than did freezing with other agents
  (p<0.001) or chilling of platelets at 4 degrees C for 24 hours (p<0.0001).
  Supernatant levels of fluorescein correlated inversely with platelet
  function. Fluorescein was also shown to be released during aggregation with
  thrombin or ADP but not during agglutination with ristocetin. CONCLUSIONS:
  Release of fluorescein into the surrounding medium indicated a loss of
  platelet membrane integrity and function. Cellular loading with FD is a
  simple method of studying membrane integrity of platelets and other cells.

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