X-Message-Number: 12352
Date: Tue, 31 Aug 1999 06:24:43 -0700 (PDT)
From: Doug Skrecky <>
Subject: formalin and RNA

  Gruber AD.  Moennig V.  Hewicker-Trautwein M.  Trautwein G.
  Institute of Pathology, School of Veterinary Medicine, Hannover, Germany.
  Effect of formalin fixation and long-term
  storage on the detectability of bovine viral-diarrhoea-virus
  (BVDV) RNA in archival brain tissue using polymerase chain reaction.
  Zentralblatt Fur Veterinarmedizin - Reihe B.  41(10):654-61, 1994 Dec.
  Detection of DNA or RNA in formalin-fixed, paraffin-embedded tissues using
  polymerase chain reaction (PCR) may be hindered by degradation of nucleic
  acids during tissue collection, preparation and archivation. This study
  describes investigations on the effect of formalin fixation and prolonged
  storage of paraffin-embedded tissues on bovine
  viral-diarrhoea (BVD)-virus RNA as a model system. Brain tissues from eight
  persistently BVDV-infected calves containing high amounts of the virus were
  fixed in 5% neutral-buffered formalin or 10% non-buffered formalin for
  different fixation times, respectively, and paraffin embedded. Subsequent
  detection of an 803 bp fragment from single tissue sections using nested PCR
  after reverse transcription (nested RT-PCR) demonstrated a loss of
  detectability of viral RNA after more than 10 days (10% non-buffered
  formalin) and 3 months (5% neutral-buffered formalin) of fixation. Additional
  studies with 280 initially BVDV-positive brain tissues from 25 persistently
  BVDV-infected calves after storage of up to 10 years
  revealed a loss of detectable RNA after more than 1 year of
  storage. For estimation of the higher sensitivity of nested
  RT-PCR compared to single step RT-PCR, serially diluted BVD virus suspensions
  were examined using both methods. Nested RT-PCR was found to be about
  100-fold more sensitive than single-step RT-PCR, and is therefore recommended
  as the appropriate technique for archival studies.

Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=12352