Hello again, to Joe, Jim and others, Jim and Joe - I think it goes without saying that you both make great and very appropriate points with regards to "high speed" sorting and, frankly, I thank you very much for posting these comments to the List. Right off the bat, I agree heartily that we ought refer to "high-pressure" sorting rather than "high speed," as we know that many people, when applying the later term, are thinking of little more than "events per second." There are far too many variables, from differing pressures, drive frequencies and stream velocities to inherent cell (or other particle) "fragilities" and media used, that perhaps even more specifics should be supplied when one wishes to talk of "faster" versus "slower." I was deliberately general in terms when posting my question, as I was looking for any reference(s)/data that may have even just addressed the question, whether at 25kHz, 66kHz, 100kHz or other, 10psi, 60psi, or more, immediately post-sort, one or four days later, etc. Because I suspect (and I've not been able to find much of anything) that there is little published data on this topic, I thought I'd cast a rod. It seems a wide open enough area (and one we'll likely never narrow too much), that perhaps I should be more specific: I would like to take an experimental look at this myself as it seems to me it may be useful (at least it will for our purposes here). I am thinking of comparing, roughly, the following conditions: 5-15 psi / 10-25ish kHz versus 50-60psi / 90-110kHz using primary human and/or murine immune system cells (probably just DCs and T and B cells for now), things such as media, culture, and perhaps any stimulation conditions being equal; looking at various indicators of life like proliferation and cytokine production; hours after sorting, a day or two later, then days later. In my little world this is all I'd like to look at for now. I am glad, however, that I posed my original question as I did, as I am pleased to see the type of discussion on the List as we have. There are innumerable different pre-, sorting, and post-sort conditions that can affect viability (another can of worms), and moving to talk of "high-pressure" versus "high speed" is at least a start. 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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