On Wed, 6 Oct 1999, Heike Grabsch wrote:

> I am looking for a protocol to use acridine orange staining for the 
> demonstration of DNA and RNA in formalin fixed paraffin embeded tissue 
> sections. In the textbook I only find a procedure for cell smears or do 
> you use it in the same manner?.

  Yes, but you will probably not get the different fluorescent
  colours (green DNA, orange-red RNA) if the fixative was formaldehyde.
  The method works best after an alcoholic fixative such as Carnoy.
  Bouin's fixative completely prevents the 2-colour effect. 

  For a DNA + RNA stain for formaldehyde-fixed material, methyl green
  & pyronine is excellent, but needs care to get it working well. Like
  so many staining methods, it is better after almost any fixative
  other than neutral formaldehyde. 

  You can do various photographic tricks to get enhanced images of
  nucleic acid staining. I will post something about this to
  HistoNet in the near future.

 John A. Kiernan,
 Department of Anatomy & Cell Biology,
 The University of Western Ontario,
 LONDON,  Canada  N6A 5C1