DNA fragmentation - (Jun/20/2012 )

Hi to All

I am trying to assess apoptosis induction by DNA fragmentation (DNA laddering).
I lysed my cells by lysis buffer and purified DNA by Phenol-chloroform- isoamylalcohol. But unfortunately I have'nt detect the ladder until now. I seed the cells in 6 well duplicate for each concentration. and I run 6microgram DNA in agarose gel .
I would be glad and appreciated If anybody introduce a sufficient protocol.
thanks

Have you tried everything in this protocol?

http://www.immunologia.unimore.it/SITO%20AC/APOBOOK98/CHAP4.HTM