Physiology, Signal Processing and Biotelemetry Laboratories

Keck Center for Microfocal Imaging
The Keck Center for Microfocal Angiography, lauched in 1994 by a grant to Marquette University from the W.M. Keck Foundation, possesses unique capabilities for x-ray microfocal imaging research. Led by Dr. Dawson, a present focus of the center is on physiological and pathophysiological studies of the lung. The microfocal imaging system, uses a 3 micrometer focal spot x-ray tube, and is the only one of its kind for biological studies. The microfocal imaging system enables the examination of blood vessels and small airways as small as 30 microns.

The x-ray microfocal imaging technology is used to study conditions such as asthma, lung tumor perfusion, and Infant Respiratory Distress Syndrome in dynamic, planer imaging and computed tomography (CT) modes.

Lung Physiology Laboratory
The circulation of the blood through the lungs plays a vital role in transporting oxygen from the lungs to the rest of the body. In addition, many blood-borne substances are metabolized on passage through the pulmonary circulation. These functions can be compromised in patients with high pulmonary blood pressure, blood clots in the lung vessels, respiratory failure, and other conditions. Studies conducted i n the Lung Physiology Laboratory at the VA Medical Center in Milwaukee are designed to determine the nature of the damage to the pulmonary circulation caused by these conditions in terms of the nervous and chemical control of the pulmonary vascular muscle and the influence of mechanical obstruction. Another objective is to develop methods that do not require extensive surgery for evaluating the nature and magnitude of the lung damage. Experimental data are collected using appropriate animal models of normal and abnormal circulation. The data are evaluated using mathematical models of the circulation of the blood through the lungs. An important aspect of the research involves the determination of which aspects of the mathematical model are useful for making such evaluations in a clinical setting. The Lung Physiology Laboratory is headed by Drs. C. Dawson with collaboration from S. Audi, A. Clough, R. Johnson , G. Krenz, M. Merker, L. Olson, D. Rickaby, and D. Roerig.

Current research projects funded by the VA, the NIH-HLBI, the American Heart Association, and the Whitaker Foundation include the study of pulmonary disposition of various lipophilic amine compounds which possess unique characteristics making them suitable indicator probes in the multiple indicator dilution method, pulmonary endothelial metabolism and oxidation/reduction using optical instrumentation, and cellular bioreactors, mathematical models of the chemical kinetics of the effect of shear stress on nitric oxide production in the lung, fractal models of pulmonary hemodynamics, and ligand binding kinetics of the pulmonary endothelium.

Biotelemetry & Implantable Electronic Device Laboratory
Cardiovascular Function Laboratory This laboratory, under the direction of Dr. D. Jeutter, is a first rate facility for the design and prototype development of biomedical devices such as multiple channel telemeters and wireless transcutaneous radio frequency powering systems for applications such as auditory prosthesis, artificial heart, nerve regeneration stimulator (Regenerative Electrical Stimulation), and for a variety of monitoring and powering needs in research. The facilities include modern, fully equipped radio frequency capability including a digital spectrum analyzer, s-parameter based network analyzer, CAD circuit analysis and design, printed circuit CAD, high frequency oscilloscopes, power meter, synthesize d radio frequency generator, and a precision oven. A darkroom allows for the complete fabrication of printed circuit boards from photographic negative through chemical etching of the boards. Complete system development from concept through realization of working prototypes is, therefore, available.

Cardiovascular Function Laboratory
The physiologic properties of the heart and arterial system encompass the primary focus of this laboratory located in the Medical College of Wisconsin's Department of Anesthesiology. Six independent state-of-the-art hemodynamic data acquisition and analysis laboratories enable the application of complex physiologic models to experimentally measure pressure, flow, volume, and wall motion waveforms. These variables can be studied under normal as well as pathological conditions including myocardial ischemia , myocardial infarction and ventricular failure in order to understand the causes and treatments of such diseases. New areas of research led by Dr. D. Warltier include stimulation of new coronary blood vessel growth (angiogenesis) and the identification of endogenous growth factors resulting from ischemia.