[Histonet] the ongoing saga of muCD31 staining

[Christian Franci]

hey you zany histokids!
All told, Iv'e gotten several Ab's to work on FFPE sections.  The 
staining is reproducible, clean but it's never super strong.  It seems 
that any time you have to do enzyme digestion there's a VERY FINE line 
between under-digestion and over-digestion of the section and when you 
have several dozen to do at once, well, the timing is not always 
precise....
anyhow, I found a nice paper in Nature from 2006 from Gavin Thurston's 
group over at Regeneron.  They have these beautiful images of mouse 
blood vessels.  Of course, being a Nature paper, the details are rather 
vague... but, I noticed something interesting...
they used pyronin-y as a counter-stain not hematox.  I've personally 
never used this or heard of it...
Have any of you used this stain? is it simple to use or are there 
"tricks" involved? Can it be used in FFPE sections or just in frozen 
ones?

As usual, thanks in advance for any help you can give me.
Cheers
Chris