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Rhythmic Rx. Parkinson's disease (PD) is a severe, progressive neurological disorder affecting a growing population of elderly people. It is most often treated with medication, a treatment that tends to become less effective with time, leaving patients severely disabled and unable to care for themselves. People with PD can often be identified by their walk -- small, shuffling steps and characteristic stiffness in both the upper and lower parts of the body.

In groundbreaking work, Robert Wagenaar, a SAR associate professor and chairman of the department of physical therapy, Terry Ellis, a SAR clinical assistant professor of physical therapy, and doctoral student Ying Hui Chou (SAR'04), all at Sargent College's Center for Neurological Rehabilitation, are investigating new therapeutic interventions for people with PD. These interventions hold promise for restoring more normal walking patterns and may help to delay intensive regimens of medication and subsequent deterioration in quality of life.

The researchers observed that while normally people use a variety of gait patterns, shifting patterns seamlessly as their walking speeds up, people with PD seem to be stuck in a single pattern. PD patients also show very little variability within a single pattern -- the small adjustments in body position that occur in response to small changes in the environment don't happen for people with PD. The researchers have found that rhythmic stimulation -- both auditory (music with a strong beat) and visual (repeating visual patterns such as stripes on the floor) -- helps people with PD increase their ability to switch between gait patterns and hence walk with a more normal pattern at appropriate speeds. Their steps get longer, their pace quickens, and their arms and body move more normally.

Using a sophisticated new virtual reality system to more precisely control visual effects, the investigators are seeking to learn how to maximize the therapeutic value of rhythmic input for people with Parkinson's disease, and to understand more about the neurological impact of rhythm on the brain.

Abracadabra. Imagine putting a collection of tiny building blocks of various shapes and sizes into a container, shaking for a time, and opening the container to find a fully functional dollhouse, complete with doors, windows, rooms, and stairways. Joe Tien, an ENG assistant professor of biomedical engineering, proposes to use an analogous process, known as self-assembly, to organize cells into more fully functional engineered tissue than is possible with the processes currently in use.

Crystal growth, one of the basic processes used by materials scientists, is one example of self-assembly. In this case chemical building blocks "grow themselves," creating complex and often useful three-dimensional geometric structures. Biological systems use self-assembly to create very complex, small-scale structures, such as cells and viruses. Tien's research, for which he recently won a Provost's Innovation Fund award, will develop biological self-assembly on a larger scale, as a process to engineer complex tissue capable of replacing damaged tissue in organs such as the liver, pancreas, blood vessels, lungs, and brain.

Current methods of tissue engineering rely on seeding mixtures of isolated cells onto a biodegradable scaffold. The addition of growth factors may promote the growth of different types of cells, but generally the resulting tissue contains a limited variety of cells, is relatively flat, and possesses little internal structure. Biologically engineered skin, for example, can be successfully grown by current methods, but functioning kidneys, hearts, and livers cannot.

Tien's technique relies on creating small structures built from tiny gel components of various shapes that are coated on one or more surfaces with thin liquid films. Shaking a number of the gel components together causes them to form into three-dimensional structures -- the pieces are attracted and bound together by capillary action between the coated surfaces. The shapes of the gel components are designed so that the final structure resembles the natural structure of the tissue to be replaced.

Tien's first goal is to incorporate several different kinds of cells into branching structures that will function as a vascular network. The successful creation of such networks is an essential first step toward creating complex organs that rely on a vascular system to nourish their cells and carry away waste products.

"Research Briefs" is written by Joan Schwartz in the Office of the Provost. To read more about BU research, visit http://www.bu.edu/research.

29 March 2002
Boston University
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