Brooke McGuire

I recently finished my master's degree from the Program in Applied Mathematics from the University of Arizona. I am currently working towards a Ph.D. from the Biomedical Engineering Program, also at the University of Arizona. I am working with Dr. Tim Secomb developing a mathematical model to investigate how various aspects of oxygen transport from the microcirculation into exercising muscle tissue affect maximum oxygen consumption. The model is based on Krogh's tissue cylinder model, with the assumptions that the capillaries are uniform and evenly spaced, and that each capillary is the exclusive oxygen supply for a cylindrical region of tissue surrounding it. The present model includes axial decline of oxygen within the blood as it flows along the capillary, and it examines the effects of a Michaelis-Menten form for the oxygen consumption rate on overall consumption. We also include the effects of intravascular resistance to oxygen diffusion within the capillary and the effects of myoglobin facilitated oxygen diffusion within the tissue. The model can be used to estimate maximal oxygen consumption and to predict oxygen levels within the tissue cylinder. Theses results can be used to investigate the relative importance of intravascular resistance and resistance to diffusion within the tissue to overall oxygen delivery. Recent experimental evidence suggests that enzyme activity in the mitochondria during the Kreb's cycle is the limiting factor for oxygen consumption. Our model is consistent with the results of these experiments as well as experimental measurements of maximal oxygen consumption. According this model, oxygen levels are low in most of the tissue at maximal consumption. Under these conditions, intravascular resistance greatly reduces oxygen delivery to the tissue. While finishing my masters degree I was partially supported by the Flinn/IGERT initiative. Not only did the Flinn/IGERT initiative give me financial support that lessened my teaching responsibilities and allowed me to concentrate more fully on my research, it also gave me an opportunity to discuss my work with both students and faculty from a variety of disciplines. As my research continues, I continue to turn to many of the contacts which I developed through the Flinn/IGERT initiative.