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W. G. Pritchard Lab Seminar: 11:15 AM - 12:15 PM, 106 McAllister Bldg

	            **Monday April 17, 2006**
	
Mathematics & Medicine: Transport vs Physiology in the Esophagus

James G. Brasseur

Department of Mechanical Engineering
Penn State University

Abstract:

I shall explore the interface between mathematics and medicine with an 
approach in which mathematical models are combined with in vivo data to 
generate new data of direct physiological importance. We integrate the 
local equations of motion across the esophageal wall to produce global 
differential equations with solutions that relate total muscle tension to 
intraluminal pressure and geometry. This model is combined with high-
resolution concurrent manometric and fluoroscopic data to predict the 
spatio-temporal patterning of wall tension in the esophageal circular 
muscle during bolus transport in the esophagus. We further develop a 
second model of "passive" wall tension parameterized using mano-
fluoroscopic data in the physiological resting state. The combination of 
the two mathematical models with in vivo concurrent manometry and imaging 
data generates new data that describes the neurophysiology of the 
esophagus and space-time distributions of circular muscle tone during 
esophageal peristalsis (contraction). We then reformulate the model and 
apply it to the opening of the lower esophageal sphincter in reflux, as an 
extension of physiological data to a part of parameter space inaccessible 
experimentally. In the process, an important discovery is made with 
functional and clinical implications. I hope to convince the audience that 
mathematical models can be viewed as extensions of physiological 
experiments when properly combined with data, and that such extensions 
have the potential to uncover important elements of physiology and 
function otherwise unattainable.

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