It may be in your best interests to do frozen sections per Terry Hacker's
suggestion, be sure to cryoprotect in 20% sucrose, and possible cut a bit
thicker, say even 10 um or so.  

It certainly is easy to visualize areas of blue color against white
OCT/frozen tissue background IF you get a high concentration of color in an
area of the embryo.  

You can let these frozen sections air dry for 30 min or longer, and
counterstain with nuclear fast red. 


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