RE: SEM
vanburen%flovax.dnet.wayne.edu@rocdec.roc.wayne.edu
Fri, 2 Aug 1996 16:17:37 -0400
>A friend of mine is not sure whether he would like to get a SEM for his
>Ventage. He's going to sort mainly the neoplastic cells. Any suggestions or
>advice? Thanx.
>
The SEM works well. Even though my fluorescense regions are usually
rectangular, my FSC/SSC region is usually non-rectangular (polygon). Keep
in mind, however, that with Consort32 (HP LYSYS II), you cannot use the SEM
with the ACDU. With a FACStation (CellQuest), you CAN use both at the same
time. Also, don't forget that you can use logical gates with the SEM; with
the standard sort comparitors, you essentially only get the AND function.
This is helpful, for instance, when I want to sort G1=R1 AND R2, and also
collect the "non-sort" G2=R1 AND NOT R2, (R1 is FSC/SSC, and R2 is
fluorescense). This is trivial if R2 is a histogram region, but no so if R2
is defined on two parameters, FLx/FLy.
>This made me wonder how 'elliptical' really the SEM elliptical gates are?
>Does anybody know the degree of approximation of ellipses the SEM uses? How
>many chanels wide are the little rectangles at the edges? Or is it
>completely different than I imagine?
>
The SEM uses the elliptical (or polygonal, or trapezoidal, or rectangular)
regions drawn by either HP LYSYS II or CellQuest. Both programs are capable
of making "pointy" ellipses that have 1-channel wide edges. The SEM sees
regions as "bitmaps". I'm not sure what the resolution of the bitmap is.
/\/\/\_ Eric Van Buren, vanburen%flovax.dnet@rocdec.roc.wayne.edu
\ \ \ Karmanos Cancer Institute and Wayne State University
\_^_/ Immunology & Microbiology, Detroit, Michigan