Sometimes we put it through an 18 gauge needle and syringe about 10 times. I think it says in Maniatis. --Julia Hsi Morris jhmorris at utmdacc.mda.uth.tmc.edu or zzhao at utmdacc.mda.uth.tmc.edu Dept. of Neuro-Oncology, Box 316 University of Texas M.D. Anderson Cancer Center Houston, TX