For those interested functional analysis of progenitor cells using rat
calvaria model, access this publication

Two color image analysis discrimates between mineralized and unmineralized
bone nodules in vitro. Purpura KA et al. Biotechniques 34(6):1188, June 2003. 

The technics alone were worth the time to read.  
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