I use the Fisher Microprobe station for my IHC staining which uses capillary
action to draw up the solutions onto the slide.  Last week, I finished up a
round of slides using the Vector Red cromagen (Alk-phos staining procedure)
with various primary antibodies of interest (vimentin, cytokeratin, c-myc,
MDM2).  Many of the tissues have a noticeably increased staining region on
the lower front of the tissue.  Kind of like the Vector Red settled due to
gravity and left a gradient of stain, even though the tissues were
completely covered with solution.

I  even tried to stain once keeping the slides horizontal during the
cromagen step, but that didn't seem to make that much of a difference.

Anyone seen anything like this before?  I never saw this with DAB.

*********************************
Catherine "Katie" Bresee Bennett
Sr. Research Technologist
Lovelace Respiratory Research Institute
Albuquerque, New Mexico