RNA - Isolation - Which protocol is the likely best of RNA Isolation? (Mar/13/2002 )

Hi,
I would like to isolate RNA from Cultured cells.
How many cells are at least necessary to be able to isolate RNA from them?
And which is the best reagent to use for isolation? (RNAZOL, TRIZOL or others?)

Thank you.
Dirk

trizol

I also use Trizol and never failed.