X-Message-Number: 11544
Date: Sun, 11 Apr 1999 18:24:09 -0700 (PDT)
From: Doug Skrecky <>
Subject: fragmented DNA and postmortum delay

Authors
  Lucassen PJ.  Chung WC.  Vermeulen JP.  Van Lookeren Campagne M.  Van
  Dierendonck JH.  Swaab DF.
Institution
  Graduate School Neurosciences Amsterdam, Netherlands Institute for Brain
  Research, The Netherlands.
Title
  Microwave-enhanced in situ end-labeling of
  fragmented DNA: parametric studies in relation to postmortem delay and
  fixation of rat and human brain.
Source
  Journal of Histochemistry & Cytochemistry.  43(11):1163-71, 1995 Nov.
Abstract
  In situ end-labeling (ISEL) identifies DNA fragmentation in
  apoptotic or necrotic nuclei in tissue sections. However, application of ISEL
  on human brain requires conservation of DNA integrity during the postmortem
  delay (PMD) and good accessibility of fragmented DNA after (prolonged) tissue
  fixation. We therefore investigated ISEL in relation to PMD and fixation in
  rat and human brain. Application on a unilateral lesion model in perfused rat
  brain revealed that prolonged post-fixation strongly diminished ISEL results.
  However, microwave pre-treatment can counteract these masking effects without
  inducing nonspecific labeling contralaterally. On the other hand, in briefly
  post-fixed, perfused brain or immersion-fixed rat and human PMD brain,
  microwave pre-treatment was deleterious and induced strong nonspecific
  labeling. In young rat brain, PMD did not influence the low numbers of
  apoptotic nuclei until 24 hr PMD, when massive nuclear labeling occurred. In
  human cortex, DNA fragmentation patterns were independent of duration of
  fixation or PMD and were already present from 4.25 hr PMD onwards. Our data
  suggest that ISEL on human brain represents antemortem DNA damage rather than
  PMD artifacts. Furthermore, microwave pre-treatment appears beneficial only
  in particular fixation conditions.

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