Why not use a fluorochrome that is red, Alexa 546 is brilliant, red, and
you get specific staining for what you want to see in contrast with
autofluorescence - then the Alexa 488 doesn't fight with muted greenish
autofluorescence not easy to quench.  Ongoing problem, more answers in
Histonet archives also.  

Access this publication, J Histochem Cytochem 49(12):1565-1571,2001 Control
of autofluorescence of archival formaldehyde-fixed, paraffin embeddded
tissue in confocal laser scannin microscopy. Baschong, et al. 

PFA and formalin fixed tissues both will autofluoresce, this was an
excellent article on how they quenched, although on paraffin sections.  It
may work for frozens also, if you play with their methods.


Gayle Callis
MT,HT,HTL(ASCP)
Research Histopathology Supervisor
Veterinary Molecular Biology - Marsh Lab
Montana State University - Bozeman
S. 19th and Lincoln St
Bozeman MT 59717-3610

406 994-6367 (lab with voice mail)
406 994-4303 (FAX)

email: gcallis@montana.edu