Hi Bob, I have some data on cell volume measurements in lymphoid cells. The reference is: MDR1/P-glycoprotein function II. Effect of hypotonicity and inhibitors on Cl- efflux and volume regulation. Weaver JL, Aszalos A, McKinney L. Am. J. Physiol. 270 (Cell Physiol. 39): C1453-C1460, (1996). The bottom line is that in a lymphoid cell lines, FS signals decrease with increased cell volume (Coulter volume measurements). This decrease in FS is thought to be due to the absorption of the normal cell surface villi found on lymphoid cells with the increased cell volume. We looked at a non-lymphoid cell line (NIH 3T3) but did not see any change in either scatter parameter associated with cell volume changes. -Jim Weaver ************************************************* * * * James L. Weaver Ph.D. * * Division of Applied Pharmacology Research * * Office of Testing & Research * * CDER MOD-1, FDA * * 8301 Muirkirk Rd, Laurel MD 20708 * * * * Phone: 301-827-8237 * * Fax: 301-594-3037 * * Email:WEAVER@CDER.FDA.GOV * * * * This email is my personal communication and * * is not in any way official U.S. FDA Policy * ************************************************* * -----Original Message----- * From: Zucker.Robert@EPAMAIL.EPA.GOV * [mailto:Zucker.Robert@EPAMAIL.EPA.GOV] * Sent: Thursday, June 13, 2002 12:44 AM * To: Cytometry Mailing List * Subject: Apoptosis light scatter detection * * * * At a recent lecture on apoptosis, the hypothesis was put fourth that * cell volume accompanied by ion changes were the very significant and * initial events during apoptosis in lymphoid cells. It was * suggested that * these changes came prior to caspase changes, mitochondrial changes, * membrane potential changes and nuclear fragmentation. * * 1. What is the current thinking regarding the sequential * events in the * apoptosis process that can be detected by fluorescent-based * assays like * flow cytometry? * * 2. After the lecture, I asked the speaker the question regarding the * capability of a flow cytometer to detect early size changes * using light * scatter. Does the flow cytometer have a sufficient sensitivity to * measure early volume changes by light scatter? What is the * percentage * decrease in cellular volume that would be necessary to * effectively make * the conclusion that cell volume size changes are the initial event in * the apoptosis pathway? The speaker did not think this was a relevant * question and felt it was only a technical question in which * the operator * of the equipment could easily answer. In my opinion in order to prove * the hypothesis that cell volume is indeed an initial event in the * apoptosis pathway, one has to understand how effective the flow * cytometer will be in determining early size changes using the light * scatter parameters. Can small changes in light scatter be * detected early * in the apoptosis process and thus be used as an initial * measurable flow * cyotmetric event in the apoptosis pathway? * Bob * * * Robert M. Zucker, PhD * U.S. Environmental Protection Agency * Office of Research and Development * National Health and Environmental Effects Research Laboratory * Reproductive Toxicology Division, MD 72 * Research Triangle Park, North Carolina, 27711 * Tel: 919-541-1585; fax 919-541-4017 * e-mail: zucker.robert@epa.gov * * *
This archive was generated by hypermail 2b29 : Sun Jan 05 2003 - 19:26:13 EST