Entering autofluorescence as a search term at
http://www.histosearch.com brought up 100 hits
all dated in the last 3 years. This is a problem
many people have, and the number and variety of
remedies indicate that there's no perfect solution.
In one recent comparative study, Baschong, Suetterlin
and Laeng (J. Histochem. Cytochem. 49:1565-1571, 2001)
found that staining for 30 min with 0.1% sudan black B 
in 70% alcohol, after immunofluorescent staining,
solved most autofluorescence problems. After staining
the dye was washed off with a jet of a modified Hanks's
solution and then immersed in the same solution for
10 minutes. The authors said this washing was necessary
to avoid formation of a black precipitate.

                            John Kiernan
                            London, Canada
-----------------------------------
"Hines, Edith M." wrote:
> 
> >         I am having some difficulty overcoming background staining on
> > formalin-fixed, paraffin-embedded, human lung tissue sections.  I have
> tried blocking
> > the tissues with chromotrope 2R, and with ammonium chloride.  Both of
> these
> > methods have not significantly reduced the amount of autofluorescence that
> I
> > observe.
> >          Any advice that may be able to provide would be greatly
> > appreciated.
> >
> > Thank you for your time,
> > Edie Hines
> > Research Technologist
> > Mayo Clinic Scottsdale
> > hines.edith@mayo.edu
> >