Thanks for the response. It has been more than 20 years since I
worked with this stuff. What I am attempting to model the effect on
cancerous plasma cells of the drug Cytoxan. The patient has Multiple
Myeloma and has under gone two transplants and a stem cell boost. The
patient had relapsed again I is under going a new chemo regimen of
Dex, Velcade and Cytoxan. We so far have five sample points of 8.58,
5.80, 2.04, 1.42 and 1.28. The data looks like it is a decaying
exponential. The last two points have brought the patient into the
normal range but now appear to be tapering off. Each sample point is
the cancer marker for that week.

I can not seem to get the screen shot for function argument.

Though at this point there is not sufficient data to model this
situation I believe I am on the right track. I have never worked with
this capability it Excel so the reason for the post.


Hopefully, you can give me more help with how to use this capability
in Excel.

Thanks,
oldman


On Fri, 12 Jun 2009 19:34:19 -0700 (PDT), Herbert Seidenberg
wrote:

Excel 2007
http://en.wikipedia.org/wiki/Biological_half-life
...isotope decays perfectly according to first order kinetics ... a
living organism follows more complex kinetics....
I suspect that you are seeing a second order rate equation curve.
Here is a comparison:
http://www.mediafire.com/file/uzuizg...06_12_09a.xlsx