if you do not have massive, synchronous apoptosis, then the ladder fraction
will be vanishingly small. You can improve the possibility of detecting it
by using end-labeling, which reduces the bias of mass. Purification of
the DNA essentially removes the bulk intact DNA to concentrate the ladder,
but you may find that you are measuring only artifactually broken DNA. See
our paper (Zakeri, Lockshin et al in the spring of 1993, FASEB J, or
articles by F. Oberhammer, M. Sikorska, and J. Isaacs. (If you can't
find them by a literature search, check back. I have my database on another
computer.)
Richard A. Lockshin
Dept. of Biol. Sci.
St. John's University
8000 Utopia Parkway
Jamaica NY 11439 USA
Phone: 718: 990 1854
Fax: 718: 380-8543
