differetiation of cells - (Jan/16/2007 )

Hi,
I have spent the last couple of weeks growing U937 cells, and they are looking great. I need to differentiate them and am planning on using ATRA. I have ordered it and know I need to dilute it in ethanol, but am not sure the quantities. If anyone has any suggestions please let me know if possible!
Cheers
Loren

http://cancerres.aacrjournals.org/cgi/content/full/61/1/178

This paper says 40nM for 5 days.

Thank you exploresci!
I have added the ATRA and am now awaiting my results!