[BioC] affy expression values
Larry
l.heisler@rogers.com
Mon, 29 Jul 2002 08:39:30 -0400
This is a multi-part message in MIME format.
------=_NextPart_000_0025_01C236DB.74C991A0
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Greetings Dr. Irizarry and Dr. Gautier,
I have a question regarding the affy procedures that I am hoping you can =
help me with. I am in the process of exploring use of affy analysis as =
an alternative to using the Affymetrix expression values and in doing so =
I am trying to understand the process for generating expression values. =
Specifically, the medianpolish default procedure used by the express =
function. =20
As I understand it, in calculating expression values for multiple chips, =
medianpolish does not treat the chips independently. It runs through =
this process of removing row and column medians for all the chips then =
generates an overall value for all the chips with corrections for each =
chip. The expression value generated is then calculated from these two =
values. Does this then mean that I should expect different results =
depending on the number of chips I am analyzing?=20
For example, I've run a subset of data through the process, using chips =
hybridized with extract from untreated cells and cells exposed to =
various treatment. I then analyzed the cells using 2 chips, 3 chips, 4 =
chips and 5 chips (ie. untreated + 1-4 treatments), and the results I =
obtained were different each time. Below is the values generated for 10 =
genes in for the untreated condition only.
gene 2 chips 3chips 4chips 5chips=20
untreated 203307_at 8.47863 8.42976 8.213314 8.44459=20
205793_x_at 9.063024 9.022368 8.84279 9.022368=20
209168_at 7.840245 7.743475 7.584038 7.817369=20
210260_s_at 10.42869 10.37537 10.02658 10.42127=20
210373_at 8.373434 8.366322 8.076776 8.366322=20
214692_s_at 8.729106 8.765005 8.457484 8.769177=20
215294_s_at 6.884695 6.95363 6.691277 6.849249=20
216017_s_at 8.90209 8.637539 8.472341 8.830136=20
217431_x_at 7.288174 7.246028 6.960451 7.288174=20
59437_at 7.960958 8.008521 7.547648 7.834895=20
I recognize that the values don't vary greatly, but I am concerned that =
having a treatment that causes profound effects to expression of certain =
genes may affect my results considerably (with respect to not having =
had done that treatment). =20
I hope my question is clear and would very much appreciate your comments =
on this.
Regards
Larry Heisler
Dept of Laboratory Medicine and Pathobiology
Program in Proteomics and Pathobiology
University of Toronto
Toronto, Ontario Canada
l.heisler@rogers.com
------=_NextPart_000_0025_01C236DB.74C991A0
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
<META content=3D"MSHTML 6.00.2600.0" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Greetings Dr. Irizarry and Dr.=20
Gautier,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I have a question regarding the affy =
procedures=20
that I am hoping you can help me with. I am in the process =
of=20
exploring use of affy analysis as an alternative to using the Affymetrix =
expression values and in doing so I am trying to understand the process =
for=20
generating expression values. Specifically, the medianpolish default =
procedure=20
used by the express function. </FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>As I understand it, in calculating =
expression=20
values for multiple chips, medianpolish does not treat the chips=20
independently. It runs through this process of removing row and column =
medians=20
for all the chips then generates an overall value for all the chips with =
corrections for each chip. The expression value generated is=20
then calculated from these two values. Does this then mean =
that I=20
should expect different results depending on the number of chips I =
am=20
analyzing? </FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2> For example, I've run a subset of =
data=20
through the process, using chips hybridized with extract from untreated =
cells=20
and cells exposed to various treatment. I then analyzed the cells =
using 2=20
chips, 3 chips, 4 chips and 5 chips (ie. untreated + 1-4 treatments), =
and the=20
results I obtained were different each time. Below is the values =
generated=20
for 10 genes in for the untreated condition only.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV>
<TABLE style=3D"WIDTH: 288pt; BORDER-COLLAPSE: collapse" cellSpacing=3D0 =
cellPadding=3D0 width=3D384 border=3D0 x:str>
<COLGROUP>
<COL style=3D"WIDTH: 48pt" span=3D6 width=3D64>
<TBODY>
<TR style=3D"HEIGHT: 12.75pt" height=3D17>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; WIDTH: 48pt; BORDER-BOTTOM: #c0c0c0; HEIGHT: 12.75pt; =
BACKGROUND-COLOR: transparent"=20
width=3D64 height=3D17></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; WIDTH: 48pt; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: =
transparent"=20
width=3D64><FONT face=3DArial size=3D2>gene</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; WIDTH: 48pt; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: =
transparent"=20
width=3D64><FONT face=3DArial size=3D2>2 chips</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; WIDTH: 48pt; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: =
transparent"=20
width=3D64><FONT face=3DArial size=3D2>3chips</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; WIDTH: 48pt; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: =
transparent"=20
width=3D64><FONT face=3DArial size=3D2>4chips</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; WIDTH: 48pt; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: =
transparent"=20
width=3D64><FONT face=3DArial size=3D2>5chips</FONT></TD></TR>
<TR style=3D"HEIGHT: 12.75pt" height=3D17>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; HEIGHT: 12.75pt; BACKGROUND-COLOR: =
transparent"=20
height=3D17><FONT face=3DArial size=3D2>untreated</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"><FONT=20
face=3DArial size=3D2>203307_at</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"8.4786296538910708"><FONT face=3DArial=20
size=3D2>8.47863</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"8.4297602050965708"><FONT face=3DArial=20
size=3D2>8.42976</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"8.2133144444841708"><FONT face=3DArial=20
size=3D2>8.213314</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"8.4445901712901907"><FONT face=3DArial=20
size=3D2>8.44459</FONT></TD></TR>
<TR style=3D"HEIGHT: 12.75pt" height=3D17>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; HEIGHT: 12.75pt; BACKGROUND-COLOR: =
transparent"=20
height=3D17><FONT face=3DArial size=3D2></FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"><FONT=20
face=3DArial size=3D2>205793_x_at</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"9.0630243266422497"><FONT face=3DArial=20
size=3D2>9.063024</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"9.0223678130284508"><FONT face=3DArial=20
size=3D2>9.022368</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"8.8427902051310703"><FONT face=3DArial=20
size=3D2>8.84279</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"9.0223678130284508"><FONT face=3DArial=20
size=3D2>9.022368</FONT></TD></TR>
<TR style=3D"HEIGHT: 12.75pt" height=3D17>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; HEIGHT: 12.75pt; BACKGROUND-COLOR: =
transparent"=20
height=3D17><FONT face=3DArial size=3D2></FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"><FONT=20
face=3DArial size=3D2>209168_at</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"7.8402454550732399"><FONT face=3DArial=20
size=3D2>7.840245</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"7.7434752994981499"><FONT face=3DArial=20
size=3D2>7.743475</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"7.58403803265095"><FONT face=3DArial=20
size=3D2>7.584038</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"7.8173686456628202"><FONT face=3DArial=20
size=3D2>7.817369</FONT></TD></TR>
<TR style=3D"HEIGHT: 12.75pt" height=3D17>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; HEIGHT: 12.75pt; BACKGROUND-COLOR: =
transparent"=20
height=3D17><FONT face=3DArial size=3D2></FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"><FONT=20
face=3DArial size=3D2>210260_s_at</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"10.428687620808001"><FONT face=3DArial=20
size=3D2>10.42869</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"10.3753653045646"><FONT face=3DArial=20
size=3D2>10.37537</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"10.026582192965201"><FONT face=3DArial=20
size=3D2>10.02658</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"10.4212654458644"><FONT face=3DArial=20
size=3D2>10.42127</FONT></TD></TR>
<TR style=3D"HEIGHT: 12.75pt" height=3D17>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; HEIGHT: 12.75pt; BACKGROUND-COLOR: =
transparent"=20
height=3D17><FONT face=3DArial size=3D2></FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"><FONT=20
face=3DArial size=3D2>210373_at</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"8.3734340419048507"><FONT face=3DArial=20
size=3D2>8.373434</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"8.3663222142458196"><FONT face=3DArial=20
size=3D2>8.366322</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"8.0767762976939306"><FONT face=3DArial=20
size=3D2>8.076776</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"8.3663222142458196"><FONT face=3DArial=20
size=3D2>8.366322</FONT></TD></TR>
<TR style=3D"HEIGHT: 12.75pt" height=3D17>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; HEIGHT: 12.75pt; BACKGROUND-COLOR: =
transparent"=20
height=3D17><FONT face=3DArial size=3D2></FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"><FONT=20
face=3DArial size=3D2>214692_s_at</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"8.7291063126486304"><FONT face=3DArial=20
size=3D2>8.729106</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"8.7650052646408199"><FONT face=3DArial=20
size=3D2>8.765005</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"8.4574843841862002"><FONT face=3DArial=20
size=3D2>8.457484</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"8.7691766634891408"><FONT face=3DArial=20
size=3D2>8.769177</FONT></TD></TR>
<TR style=3D"HEIGHT: 12.75pt" height=3D17>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; HEIGHT: 12.75pt; BACKGROUND-COLOR: =
transparent"=20
height=3D17><FONT face=3DArial size=3D2></FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"><FONT=20
face=3DArial size=3D2>215294_s_at</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"6.8846951379075403"><FONT face=3DArial=20
size=3D2>6.884695</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"6.9536303939127801"><FONT face=3DArial=20
size=3D2>6.95363</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"6.6912769974755602"><FONT face=3DArial=20
size=3D2>6.691277</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"6.8492487027644096"><FONT face=3DArial=20
size=3D2>6.849249</FONT></TD></TR>
<TR style=3D"HEIGHT: 12.75pt" height=3D17>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; HEIGHT: 12.75pt; BACKGROUND-COLOR: =
transparent"=20
height=3D17><FONT face=3DArial size=3D2></FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"><FONT=20
face=3DArial size=3D2>216017_s_at</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"8.9020900765987605"><FONT face=3DArial=20
size=3D2>8.90209</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"8.6375391095834608"><FONT face=3DArial=20
size=3D2>8.637539</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"8.4723405132201997"><FONT face=3DArial=20
size=3D2>8.472341</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"8.8301360436540595"><FONT face=3DArial=20
size=3D2>8.830136</FONT></TD></TR>
<TR style=3D"HEIGHT: 12.75pt" height=3D17>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; HEIGHT: 12.75pt; BACKGROUND-COLOR: =
transparent"=20
height=3D17><FONT face=3DArial size=3D2></FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"><FONT=20
face=3DArial size=3D2>217431_x_at</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"7.2881739681123001"><FONT face=3DArial=20
size=3D2>7.288174</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"7.2460279805281003"><FONT face=3DArial=20
size=3D2>7.246028</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"6.9604507213518998"><FONT face=3DArial=20
size=3D2>6.960451</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"7.2881739681123001"><FONT face=3DArial=20
size=3D2>7.288174</FONT></TD></TR>
<TR style=3D"HEIGHT: 12.75pt" height=3D17>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; HEIGHT: 12.75pt; BACKGROUND-COLOR: =
transparent"=20
height=3D17><FONT face=3DArial size=3D2></FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"><FONT=20
face=3DArial size=3D2>59437_at</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"7.96095786675121"><FONT face=3DArial=20
size=3D2>7.960958</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"8.0085213058109801"><FONT face=3DArial=20
size=3D2>8.008521</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"7.5476482311749402"><FONT face=3DArial=20
size=3D2>7.547648</FONT></TD>
<TD=20
style=3D"BORDER-RIGHT: #c0c0c0; BORDER-TOP: #c0c0c0; BORDER-LEFT: =
#c0c0c0; BORDER-BOTTOM: #c0c0c0; BACKGROUND-COLOR: transparent"=20
align=3Dright x:num=3D"7.8348951315787199"><FONT face=3DArial=20
size=3D2>7.834895</FONT></TD></TR></TBODY></TABLE></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I recognize that the values don't vary =
greatly, but=20
I am concerned that having a treatment that causes profound effects to=20
expression of certain genes may affect my results considerably =
(with=20
respect to not having had done that treatment). </FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I hope my question is clear and would =
very much=20
appreciate your comments on this.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Regards</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Larry Heisler</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Dept of Laboratory Medicine and=20
Pathobiology</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Program in Proteomics and =
Pathobiology</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>University of Toronto</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Toronto, Ontario Canada</FONT></DIV>
<DIV><FONT face=3DArial size=3D2><A=20
href=3D"mailto:l.heisler@rogers.com">l.heisler@rogers.com</A></FONT></DIV=
>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV></BODY></HTML>
------=_NextPart_000_0025_01C236DB.74C991A0--