At 11:22 am -0500 16/3/99, Mark A. KuKuruga wrote:
>Jill Martin wrote:
>
>> . . . I have an investigator who is looking at proliferation and would like
>> to see the uptake of Brdu in S-phase. We would like to do an accurate
>>cell
>> cycle analysis which will give us not only the percentage of each
>>phase but
>> the exact boundaries so that we can gate on them.
>
>Cell cycle fitting programs, like ModFit (verity) or MultiCycle (Phoenix) will
>fit your DNA histogram data and effectively define limits of your cycle
>compartments. These limits can then be transferred as gating criteria.
>
Hi Jill,
be aware that the fitted one-dimensional DNA distributions won't let you
assign any particular cell to its compartment. The reason for deconvolving
the histogram is indeed to "deblur" those boundaries, but it's the
histogram that gets deblurred not the cell data, and you end up with
probability information - you may find out how likely cells are to be in
each compartment, but not which ones are.
You'll notice that the results of modelling have overlapping distributions;
some of the S-phase generally ends up in the G0/G1 and G2/M "areas", and
vice versa - the closer the output is to the input, the better the fit
(generally).
You might be better off gating on the bivariate plot and forgetting the
deconvolution, at least you're just making two assumptions (that all of the
S-phase cells are labelled, and none of the G phase cells) rather than the
wide range of assumptions used in deconvolving and modelling.
Ray
Ray Hicks
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