205 Reber M.E. Bldg.
Tel:814-865-3159
Fax:814-865-1344
Email:brasseur@psu.edu
Dr. Brasseur has developed major research programs in the biomechanics and physiology of the gastro-intestinal tract, in the development of large-eddy simulation methods for turbulent flows, and in the dynamics and structure of turbulent flows. Dr. Brasseur's biomechanics programs center on the mechanical, muscular and neuromuscular processes involved in the function and dysfunction of the pharynx and pharyngo-esophageal segment, the esophagus, gastro-esophageal segment, and stomach. Of particular interest is the neurophysiological function of luminal musculature in generating bolus transport, the function of the gastro-esophageal junction and associated surgical procedures for gastro-esophageal reflux disease, the mixing and emptying dynamics underlying normal gastric physiology, and the process of drug release from the gastric cavity. These programs have been supported by several grants from the National Institutes of Health, Janssen Pharmaceutica, AstraZeneca Pharmaceuticals, and Bard Endoscopic Technologies, Inc., and have involved close collaborations with researchers at Northwestern Medical School, Zürich University Hospital in Switzerland, University of New South Wales and Adelaide Royal Hospital in Australia, Temple University in Philadelphia, the Medical College of Wisconsin, and The Johns Hopkins Medical School.
Dr. Brasseur's research contains three basic elements: the analysis of biological
data from a mechanical perspective, the development and application of mathematical
and numerical models, and the application of data analysis techniques in a
clinical setting. We analyze digitized fluoroscopic, MRI and high frequency
ultrasound images of fluid movement through the pharynx, esophagus, stomach,
and corresponding sphincters, collected concurrently with high resolution manometric
pressure data and draw biologically relevant conclusions on the mechano-physiological
processes that underlie GI function. We have been particularly interested in
the interplay between the contractile behavior of circular vs. longitudinal
muscle using high-frequency ultrasound data. The application of mathematical
and numerical models may be regarded as “extending” the biological
data to obtain detailed knowledge unavailable experimentally. Our fluid models
of esophageal bolus transport apply what is called “lubrication-theory” while
out models of the pharynx and stomach are based on the lattice-Boltzmann numerical
method. The models are always combined with biological data with an emphasis
on issues of physiological and clinical interest.
Representative Publications in Biomechanics and Physiology
Pal, A., Williams, R.B., Cook, I.J, Brasseur, J.G.. 2003 Intrabolus pressure
gradient identifies pathological constriction in the upper esophageal sphincter
during
flow. in press, Am. J. Physiol.
Nicosia, M.A., Brasseur, J.G. 2002 A Model for estimating muscle tension in
vivo during esophageal bolus transport. J. Theor. Biol. 219: 235 - 255.
Pal., A. Brasseur, J.G. 2002 The mechanical advantage of local longitudinal
shortening of the human esophagus. J. Biomechanical Eng. 142: 94-100.
Nicosia, M.A., Brasseur, J.G., Liu, J-L., Miller, L.S. 2001 Longitudinal shortening
in the human esophagus from high-frequency ultrasonography. Amer. J. Physiol.
281 (Gastrointest. Liver Physiol.): G1022-G1033.
Indireshkumar, K., Brasseur, J.G., Faas, H., Hebbard, G.S., Kunz, P., Dent,
J., Boesinger, P., Feinle, C., Fried, M., Li, M., Schwizer, W. 2000 Relative
contributions of "pressure pump" and "peristaltic pump" to
slowed gastric emptying, Amer. J. Physiol. 278 (Gastrointest. Liver Physiol.):
G604-G616.
Wu, S.J., Shung, K.K., Brasseur, J.G. 1998 In situ measurement of doppler
power vs. flow turbulence intensity in red cell suspensions. Ultrasound
in Medi.and
Biol. 24: 1009-1021.
Li, M., J. G. Brasseur, W. J. Dodds. Analysis of normal and abnormal esophageal
transport using computer simulations. Amer. J Physiol. 266: G652-G543,
1994.
Brasseur, J. G. and W. J. Dodds. Interpretation of intraluminal manometric
measurements in terms of swallowing mechanics. Dysphagia 6: 100-119,
1992.