counting of neurospheres: got some tricks? - (Dec/11/2006 )

Hello,
I am cultivating neurospheres in a 24well-plate and i need to count them with a precie protocol because the effects of my cytokines are rather subtle.
I am currently using a microscope with a X10 to X20 magnification but i hav no landmark and my countings aren't precise enough and they lack efficiency. How do you guys count yours neurospheres?

Could this help you a bit?:

http://www.stemcell.com/technical/techtip....;content_type=2