Enlightened by science

A love of science and a desire to help others has landed junior Denine Ledyard on a team of researchers studying human mast cells and their role in treating asthma and other allergies.

Denine Ledyard

Graduate students often do most of the work in research laboratories. But in one tiny, darkened biology lab, junior Denine Ledyard spends her days hunched over a petri dish, studying human mast cells.

Mast cells contain granules that store a variety of mediators. Every time something happens that needs attention from the body's immune system, mast cells rush to the rescue. Think of them as cell-sized emergency technicians. First they evaluate the environment, checking the temperature and examining the problem, then they administer first-aid—secreting the appropriate mediator.

If the problem is a blood clot, say, mast cells might secrete heparin or chondroitin sulfate, powerful anticoagulants to keep the blood flowing.

But sometimes the rescuers overmedicate. If the problem is inhaled pollen, mast cells often flood the body with histamines, causing the runny nose and itchy eyes so familiar to allergy sufferers.

Scientists know that mast cell surfaces are covered with receptors, tiny gates that open and close in response to signals from the cell's environment. What researchers don't fully understand is what signals cause the gates to open, how they open and what mediators are secreted in response to various signals.

Ledyard and other researchers working with biology Assistant Professor Malgosia Wilk-Blaszczak are characterizing one specific receptor to understand everything about how, when and why it works.

Ledyard began her UTA studies as part of the Summer Bridge Research Program, a partnership with Tarrant County College. A scholarship, awarded through the Louis Stokes Alliance for Minority Participation, has assisted her. Although many undergraduates undertake research projects, Ledyard may be unique in her persistence.

"Very soon many undergraduates realize that experimental work requires long-term commitment, hard work and dedication," Dr. Wilk said. "What makes Denine so special is that despite all the difficulties, she stuck with her desire to do science—she's stayed in the lab for almost two years now."

Under the direction of Melanie Aschenberg, a graduate researcher in Dr. Wilk's lab, Ledyard conducts whole-cell patch clamping experiments. She lowers an ultra-thin, sharp-pointed glass pipette onto a mast cell and hopes that a good seal will form. An electronic probe is threaded down the center of the pipette to measure electrical currents running through the cell membrane.

To complete the experiment, the seal between pipette and cell must be maintained for 20 minutes, a difficult and frustrating assignment.

"I learned all my swear words in the lab," Ledyard said with a laugh. Some days she works with dozens of pipettes and cells but can take the full set of measurements only once or twice.

Still, the painstaking work must be performed for researchers to know what's happening within the mast cells and how to control the secretions. An understanding of mast cells will lead to more effective treatments for asthma and other severe allergies. Further research will help explain the cells' role in infection protection and inflammatory diseases.

Ledyard's research career has only begun. "I've always been interested in science," she said. "I thought about medical school, but doctors can only use what information is already known. They can only help a few people. Researchers can help so many more."


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