IN pertaining to this e-mail and many like it, I was wondering if there is a possible way to re-define the phrase "High-Speed Sorting". I tend to visualize this phrase to refer to events/sec as being analyzed by the instrument. In some cases it could be >10k/sec in some >30k/sec. All depending upon the operator. Viability comes into question in all aspects of sorting, whether High or Low. The factor that governs this is not the speed but the "pressure" at which sorting occurs. I can sort at 12k/sec on my Vantage at 30 psi up to 45 psi. I have even sorted at 12k/sec on the old FacStar at 15 PSI. Certain cell types do not do well at higher pressure greater than 25 psi some do well even at 60 PSI. When it comes to viability, is this immediate after sorting viable cells? Cells viable 4 hrs post sorting or even 24hr post sorting? Some cells may loose their potential to proliferate/respond at higher pressures. This is only seen after days of culture. In all. You have to take into account the sorting pressure and not the speed to evaluate the sorting effects on the cells. I suggest we refer to sorting as "high pressure sorting" vrs. "high speed sorting". IN doing so it would be wise to relate what pressure we are sorting at and what type of cell we are sorting. Many are doing the "High Speed Sorting", but I would bet that we are all using different pressures to achieve this. Jim Houston Coordinator, Flow Cytometry and Sorting Cell and Gene Therapy Program St. Jude Children's Research Hospital Memphis, TN 38105 ph:901-495-2926 -----Original Message----- From: Cliff McArthur [mailto:cytocliff@netscape.net] Sent: Monday, March 06, 2000 11:17 AM To: cyto-inbox Subject: HOW viable after high-speed sorting? Hi there, flow aficionados. I know we've all addressed the post-sort viability (after high-speed sorting) question many times over. What I am looking for is not "whether" but "how much," so to speak. To that end, I'd like to ask the List if anyone knows of any published work that has addressed the question not of whether or not cells are viable after such sorting (we know they are, or can be) but "how" viable, that is, do they produce less cytokine or other product, proliferate a little more slowly, or survive for less time, etc., etc. under the same conditions versus "low-speed" sorted cells? Shucks, references that just address this question, if it is not the primary objective of the work, would be great to have. If anyone is willing to share their unpublished insights, I'd love to hear them as well. Thank you very much, Cliff McArthur University of California at San Francisco Departments of Medicine and Immunology/Microbiology 415-502-6860 ____________________________________________________________________ Get your own FREE, personal Netscape WebMail account today at http://webmail.netscape.com.
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