Often when trying to analyze DNA histograms for cell cycle or DNA analysis, the use of simple region markers on the histogram is not adequate.  Especially if the DNA histogram exhibits a lot of debris from poor sample preparation and/or there are multiple DNA populations with different DNA content in the same histogram.  When these conditions arise, it is necessary to use a powerful mathematical model to remove the debris component and deconvolute the multiple peaks in the histogram.

The MultiCycle AV DNA tool in FCS Express addresses this problem in a seamless manner.  The Dean/Jett method, which is considered the gold standard for cell cycle modeling, was first proposed in 1974.  In 1980, a modification by Fox was added to the Dean/Jett method to better fit data with complication S phase distributions.  Multicycle AV uses the Dean/Jett/Fox model.

In addition, sophisticated debris subtraction models developed over the past decade by leaders in the field of cell cycle analysis, Rabinovitch & Bagwell, are applied to the debris component.  This results in accurate, simple-to-understand cell cycle results from even the most complicated DNA histogram.

FCS Express is pleased to announce that De Novo Software has partnered with Phoenix Flow Systems and the University of Washington to combine the comprehensive DNA analysis capabilities of Multicycle AV with FCS Express.

You can now obtain the best of both worlds: the ease of use, flexible data analysis, and flexible reporting of FCS Express as well the complete suite of DNA modeling tools available in Multicycle for cell cycle analysis.

The DNA fitting engine in Multicycle has been used for over a decade by researchers all over the world and is described in several publications:

• Dean P. and Jett J., Mathematical analysis of DNA distribution derived from flow micro-fluorimetry., Cell Biology 60: 523, 1974.
• Fox M.  A Model for the Computer Analysis of Synchronous DNA Distributions Obtained by Flow Cytometry. Cytometry Volume 1, No.1 71:77, 1980.
• Rabinovitch, P.S.  DNA content histogram and cell-cycle analysis.  Methods in Cell Biology. 41:263-296, 1994.
• Rabinovitch, P.S.  Practical considerations for DNA content and cell cycle analysis.  In:  Clinical Flow Cytometry:  Principles and Applications (Bauer, K.D., Duque, R.E., and Shankey, T.V., eds.)  Williams and Wilkins, Baltimore, pp. 117‑142, 1992.
• Rabinovitch, P.S. DNA Histogram Analysis. In: Cell Growth and Division, 2nd Edition. (G. Studinski, ed.). Oxford University Press, Oxford, 1996.
• Kallioniemi, O-P., Visakorpi, T., Holli, K., Isola, J.J., and Rabinovitch, P.S.  Automated peak detection and cell cycle analysis of flow cytometric histograms.  Cytometry 16:250-255, 1994

Multicycle contains many different features to help optimize your DNA analysis:

• Multiple levels of automation, including manual, semi automated (auto detect number of cycles) and full automation (autofit) modes.
• Extremely convenient visualization of differences in fitting models, allowing comparison of appearance of the fitting result and their associated cell cycle statistics. This approach also allows intuitive and accurate assessment of the confidence of fitting parameters. The confidence estimation is based upon both the statistical confidence of a particular models and the variability in fitting results obtained by comparison of the six models automatically applied.
• Multicycle uses advanced and well documented methods of debris and aggregate software compensation, allowing the most accurate results over a broad range of sample quality and preparation methods.
• Multicycle provides a full spectrum of cell cycle statistical output that may be incorporated into your report generation, including simple and clear summary, interpretation and confidence statements.

Since Multicycle is integrated directly with FCS Express, all the features that you expect from FCS Express are available with your DNA analysis: reporting, tokens, batch processing, PowerPoint presentations and much more.

For information regarding MultiCycle AV, please visit our DNA MultiCycle Knowledge Base page.

FCS Express comes with Multicycle for free. It allows users to fit up to 3 cell cycles with background, debris, and aggregate correction within a sample.

• Learn more about DNA Analysis and modeling with MultiCycle with the free PDF, Introduction to Cell Cycle Analysis by Rabinovitch.
• Learn more about the cycles and modeling used within MultiCycle AV with the free PDF, MultiCycle AV Cell Cycle Data Display Explained.
• Learn more about MultiCycle AV in FCS Express with our DNA Analysis Recorded Webinar.
• To access our DNA Analysis tutorial, click here.
• For a summary of the Cycles and Models used in MultiCycle AV, click here.
• Multicycle is showing Inter-model or Intra-model errors for my cell cycle data. What does this mean?
  • Intra-model errors occur when the observed values in the data vary widely from what is expected in the model.
    • Some variables to that can contribute to an Intramodel error are:
      • Wide %CV of peaks
      • Low numbers of cells
      • Samples which contain more than one cell cycle and the various cell cycles overlap.
      • Poorly defined peaks.
  • Inter-model errors occur when the Gaussian fitting of each of the different models offered in Multicycle provides highly variable numbers.