RE:

From: Robert C. Leif, Ph.D. (rleif@rleif.com)
Date: Wed Jan 19 2000 - 17:12:39 EST


From: Robert C. Leif
To: cyto-inbox

The best way to measure size is with a focused flow Coulter Counter. These
are available in many clinical laboratories, since they provide the 5 part
white cell differential for the high end Coulter hematology instruments.
Flow cytometers and sorters often do not measure true Low angle light
scatter. This scatter is in the Mie region and is often blocked by the
obscuration bar. The elliptical laser beam shape is optimized for
fluorescence.

-----Original Message-----
From: Ellen Cahir McFarland [mailto:ecahir@rics.bwh.harvard.edu]
Sent: Tuesday, January 18, 2000 9:00 AM
To: cyto-inbox
Subject:



Dear all,
I am new to the list, but am interested in your input.
>
> I have some questions about the relationship of FSC to size. I have been
> trying to evaluate a B cell line for their mitochodrial potential using
> DiOC6, a potential sensitive dye. When I induce cell death in this line, I
> see two populations that differ in about 40 channels (mean) on FL-1 (log
> scale, FL1-H) for DiOC6 staining.. I also see a shift in the population by
> FSC by about 2 fold (600 to 300) on a linear scale. I want to be sure that
> the change in DiOC6 fluorescence is related to the change in potential and
> not size.
>
> Is there a relatively straight forward relationship between size and FSC?
> Does 2 fold mean 2 fold diameter? volume? neither?
>
> I never see a cell with high FSC that has low potential and the opposite
> is true also..
>
> Thanks so much.
> Ellen


Ellen Cahir McFarland

Postdoctoral Fellow
Kieff Lab
Brigham and Women's Hospital and
Harvard University
181 Longwood Ave 8th floor MCP
Boston, MA 02115
phone 617-525-4270
fax   617-525-4251
ecahir@rics.bwh.harvard.edu



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