X-Message-Number: 9950
Date: Sun, 28 Jun 1998 09:31:48 -0700 (PDT)
From: Doug Skrecky <>
Subject: can membranes be chemically preserved?  

  Of the aldehyde fixatives formaldehyde is known to offer the most
stabilization of cellular membranes in the short term. What about long term
storage? Can formaldehyde cut it? Is it good enough to serve as an
inexpensive alternative to cryonics? You decide. The following is a series
of quotes to help you decide from (J Histochemistry Cytochemistry 10:
704-709 1962) entitled "The Action of Formaldehyde Solutions on Human Brain
Lipids".
  Quotes from text:
  "Cholesterol: The cholesterol content showed a slight increase of 20.8%
in fresh white matter to 23.4% after 24 years of fixation. ...... Our
conclusions are in agreement with Rodnight's that the cholesterol content
remains unaffected by storage in formaldehyde solutions.
  Cerebrosides and sulphatides: The amount of cerebrosides and sulphatides
showed an increase from 35.5% in fresh white matter to 38.6% after 24 years
of fixation. We conclude on the same grounds as was the case with the
cholesterol content that these lipids remain substantially intact during
formaldehyde storage.
  Phospholipids: The breakdown of many phospholipids is shown in the
decrease of the phosphorus content of the total lipid extracts as
illustrated in figuare 3. The slope of this curve indicates that this
process is nearly completed after 16 years of storage.
  Lecithin and lysolecithin: ... It is remarkable that no lecithin can be
demonstrated after 12 years of storage, whereas a small amount of
lysolecithin is present even after a fixation of 24 years.
  Sphingomyelin: No breakdown of sphingomyelin could be detected.
  Phosphatidylethanolamine and lysophosphatidyethanolamine: ...The further
slow breakdown illustrated in figuare 5 is comparable with that of lecithin
and phosphatidylserine.
  Phosphatidylserine and lysophosphatidylserine: Phosphatidylserine also is
completely broken down.
  Phosphoinositides: .... remains unaffected.

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