Dear Robert, The Mitotic Index (MI) is what the name suggests, being a count of the number of mitotic cells visible (usually made with a microscope) and expressed as a fraction of the total. The DNA Index is a ratio figure of the amount of DNA in the normal (diploid) G1 peak of the cell cycle, compared to the DNA content of the abnormal G1 peak. This is usually measured by flow cytometry using a simple DNA fluorochrome (propidium iodide) where DNA content is assumed to be proportional to the amount of dye taken up by the nucleus, and therefore proportional to the intensity of fluorescence measured by the cytometer. The median channel of fluorescence is taken for each G1 peak, and the channel for the unknown peak divided by the channel for the diploid (control) peak. Thus Diploid cells will have a DNA index of 1, tetraploid =2, aneuploid somewhere in-between, and hypodiploid less than 1. For more details see a summary of the European consensus document (Ormerod et al) via the link on the UK flow cytometry/Royal Microscopical Society web page:- http://www.uwcm.ac.uk/uwcm/hg/hoy/index.html Best wishes, John.
This archive was generated by hypermail 2b29 : Wed Apr 03 2002 - 11:53:04 EST