%0 Journal Article %T Periodic Oscillations of Blood Cell Populations in Chronic Myelogenous Leukemia %A Michael C. Mackey %A Chunhua Ou %A Laurent Pujo-Menjouet %A Jianhong Wu %J Quantitative Biology %D 2004 %I arXiv %X We develop some techniques to prove analytically the existence and stability of long period oscillations of stem cell populations in the case of periodic chronic myelogenous leukemia. Such a periodic oscillation $p_\infty $ can be analytically constructed when the hill coefficient involved in the nonlinear feedback is infinite, and we show it is possible to obtain a contractive returning map (for the semiflow defined by the modeling functional differential equation) in a closed and convex cone containing $p_\infty $ when the hill coefficient is large, and the fixed point of such a contractive map gives the long period oscillation previously observed both numerically and experimentally. %U http://arxiv.org/abs/q-bio/0409002v1