CD 34 proliferation - (Mar/21/2010 )

Hi all,
I was trying to proliferate my CD34 cells for the last 3 weeks but the cells didn't grow, I am using HPGM media and different concentration of cytokines 50-100 ng/ml of SCF, TPO and FLT3, with different cell count 20,000-200,00.
Any recommendation?
Thank you in advance

What is the origin of your cells? i.e. Are they human, mouse...? How did you isolate them?

http://www.stemcell.com/ has some good stuff on there for stem cell culture such as the SFEM.