RE: A DNA analysis question -additional

From: Nicholas Terry (ntflow@odin.mdacc.tmc.edu)
Date: Tue Dec 21 1999 - 16:05:51 EST


Jim - greetings. No disagreements here.

-SNIP-

At 02:41 PM 12/21/99 -0600, you wrote:
>The width of the beam is not as big an issue as you have made it for
>pulse-width time-of-flight discrimination of doublets. 

Sure-but it can help.

>If the laser beam width is subtracted from the pulse width time-of-flight
signal in real time using a good biased amplifier, resolution is not a
problem.  The limits  of  detection depend only on how good your
hydrodynamic focusing is to deliver  all of  the cells or objects to the
same position in the beam at a steady velocity.  For  successful doublet
correction the only limit is that the heterogeneity of  nuclear  sizes  (if
you do fluorescence pulse width time-of-flight) or cell sizes (if  you do
light scatter pulse width time-of-flight). 
The implementation in commercial systems is the problem. 

-/SNIP-

I absolutely agree.

My point, made less than pellucidly, was that DNA flow cytometry is not
just immunophenotyping in the red (or blue, or whatever) channel.

Thanks for your useful input.
Best wishes,
Nick  


Nicholas Terry, M.A., Ph.D.,
Experimental Radiation Oncology - 066,
The University of Texas M. D. Anderson Cancer Center,
1515 Holcombe Blvd., Houston, Texas 77030.
'Phone: 713-792-3424,
'Fax: 713-794-5369.
http://drad52.mdacc.tmc.edu.
ntflow@odin.mdacc.tmc.edu.



This archive was generated by hypermail 2b29 : Wed Apr 03 2002 - 11:54:22 EST