DMSO in as a control

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marvins42
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DMSO in as a control

Hi all,

I've been working with some proliferation assays for a while, using 0.1% DMSO for my positive control.  However, on several assays, it doesn't work (i.e., I get higher cell numbers than my low control, but not nearly as high as they should be).   Recently, I had four assays tested in one day - all treated at the same time, same cells, same incubation, same evaluation, but the high control worked on only two of the assays.  I use the same DMSO as control and to dilute my compounds - the compounds all behave as they should, so it shouldn't be the stock solution.  No one knows what is causing the problem - I've cleaned the pipettes, used tips that prevent contamination by aerosolized compounds, checked my protocol.  Is there any reason why this is happening?  Any help would be greatly appreciated, thanks!! 

hcheung
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Hi marvins42,

Hi marvins42,

Do you use fresh DMSO solution for each time you perform the assay?

hcheung

marvins42
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Hi hcheung, thanks for

Hi hcheung, thanks for responding!

I use solution from the same stock as my compound dilutions.  The stock is maybe two or three months old.  I use a dilution plate for the compounds, and I put the DMSO on that as well (I don't resuse the DMSO ever).