Re: Using DNAse to stop samples clogging cytometer lines

Joanna

I have 3 CyAns that are heavily used and we do 
not have that problem.	We have each user run 
bleach and/or 1% Contrad70NF after every 
run.  You should not have to run DNAse.

Larry

At 09:25 AM 5/29/2008, you wrote:
>Hello everyone,
>
>In my core facility, I have a pretty heavily 
>used CyAn (at least 12 hours a day most
>days) that has lately been getting blocked quite 
>easily duirng sample runs even when
>samples are filtered immediately prior to 
>running them through the machine. I have a
>strong suspicion this relates to the presence of 
>dead cells in the samples releasing
>sticky DNA everywhere, particularly given the 
>fact that in some situations, the approach
>is to stain on one day and then leave the 
>samples over night to analyse the next day. I
>want to suggest to my users that they include 
>DNAse in their buffer to try to reduce this
>problem.
>
>DNAse is talked about in the archives of this 
>list from time to time and various
>concentrations are suggested but what is not 
>mentioned is how efficient it is when the
>samples are not at 37degrees. All our live 
>samples on this machine are on ice except for
>the moment when they are run through the 
>machine. Will DNAse still be any use? I have had
>a search through Current Protocols and I don't 
>think DNAse is mentioned in this context.
>
>If you have a DNAse protocol for this purpose, I 
>would love to know about it and would
>also appreciate any comments about the question 
>of temperature. This will really help in
>trying to solve this blocking problem which 
>takes up alot of time and causes quite a bit
>of inconvenience.
>
>Thanks very much for your help!
>
>Joanna
>
>
>--
>Joanna Roberts
>Flow Cytometry Core Facility
>Ecole Polytechnique Fédéral de Lausanne (EPFL)
>/Swiss Federal Institute of Technology
>
>Tél: +41 (21) 693 1814
>Tél: +41 (79) 832 7414
>
>EPFL-SV-SG FCCF
>Bâtiment AI
>Station 15
>CH 1015
>Lausanne
>Switzerland

Larry W. Arnold, Ph.D.
Research Professor and Director, Flow Cytometry Facility
Department of Microbiology and Immunology
CB# 7290
University of North Carolina
Chapel Hill, NC 27599
Phone: 919-966-1530
FAX: 919-843-5624
http://flowcytometry.med.unc.edu