University of Wisconsin-Madison College of Engineering Annual Report 2003
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Biomedical Engineering

Robert Radwin, Walter Block, Mary Sesto and Terry Richard

Working hands: Certain workplace exertions may harm muscles

Every day, working Americans exert their muscles in repetitive and forceful jobs. And as a result, work-related musculoskeletal disorders in the United States annually account for nearly 70 million physician office visits and cost more than $45 billion in compensation, lost wages and lost productivity, according to the Institute of Medicine.

Stretched arm

Stretched arm (19K JPG)

Normal arm

Normal arm (20K JPG)

Professor Robert Radwin (left), Assistant Professor Walter Block (seated), Associate Professor Tom Best (not pictured), Assistant Scientist Mary Sesto (standing) and Mechanical Engineering Professor Terry Richard (right) are investigating the physiological, anatomical and biomechanical properties of muscles and tendons involved in repetitive manual work. The research is supported in part by a three-year, $540,000 grant from the National Institute for Occupational Safety and Health, and by a magnetic resonance imaging (MRI) scanner GE Medical Systems recently donated to the department.

One aspect of the group's research includes studying how power hand tools used in manufacturing plants act on the hands and arms.

"Not only do people have to produce forces to use these tools, but the tools produce rapidly building forces as well," says Radwin. "The tool operator has to respond by contracting their muscles to prevent losing control. Sometimes the tools are stronger than the operator, thereby stretching the muscles."

Recent studies show these stretching contractions, called eccentric, might be harmful to muscles, he says. In controlled experiments, the researchers expose volunteers to eccentric exertions, and using both mechanical means and MRI, measure changes in the muscles and tendons.

The group hopes its results will show how these contractions occur in the workplace, whether they are involved in work-related disorders and, ultimately, how to prevent injuries.

Imaging the body's activities

Scientists regularly examine cells in labs. However, a $1.2 million National Cancer Institute grant is fostering collaborations to improve the biological understanding and imaging techniques doctors need to view cellular activities deep within the human body in real time.

Professor Thomas Grist, the grant's principal investigator, is working with Visiting Professor of Animal Science Marek Malecki to develop a contrast agent that will work with magnetic resonance imaging (MRI). Malecki is bioengineering antibodies or parts of antibodies that can target certain molecules or cells in the body.

Assistant Professor Nimmi Ramanujam and Pharmacology Assistant Professor Patricia Keely are studying how mammary tumor cells interact with collagen, a protein across which they migrate when cancer cells metastasize. And Assistant Professor Walter Block, Professor Charles Mistretta and Radiology and Neurological Surgery Professor Howard Rowley are hoping to develop MRI strategies with the speed and coverage of computed tomography.

While the main purpose of the grant is to increase understanding of biology and molecular imaging as they relate to cancer, Grist says findings could apply to other areas, including cardiovascular diseases. The key is that both analysis and imaging will be conducted within the body in real time. "In terms of medical imaging, this is going to be the frontier," he says.

Study aims straight for the heart of pulmonary disease

Assistant Professor Naomi Chesler's research on pulmonary system pressures may help some women ages 21 to 40 breathe easier. Chesler and graduate student Ryan Kobs are studying the mechanical and biological mechanisms behind the changes in arteries in women who have primary pulmonary hypertension. The rare disease progressively narrows the blood vessels in the lungs, causing high blood pressure and eventually, heart failure.

It's a vicious cycle, says Chesler, in which increased pressures lead to smaller vessels, which leads to increased resistance within the vessels, which leads to higher pressures. "And on it goes," she says.

Studying the mechanical and biological properties of arteries in mice, they've learned that the vessel walls are stiffer at higher pressures and are viscoelastic. Chesler and Kobs also discovered the vessels thicken and stiffen with exposure to hypoxia, or oxygen deprivation. Their next step is to examine the role of changes in elastin, collagen and smooth-muscle cells in the remodeling process.

Armed with an understanding of the mechanics and biology of the pulmonary vessels, researchers then can focus on developing minimally invasive diagnostic techniques or possibly finding a cure for the disease, says Chesler. The study is supported with funding from the Wisconsin Alumni Research Foundation and a three-year, $238,139 Whitaker Foundation grant.


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Copyright 2003 The Board of Regents of the University of Wisconsin System
Date last modified: 03-Oct-2003
Date created: 03-Oct-2003