Lorrel Brown

Biological Sciences

As a freshman, Lorrel Brown was encouraged by her father to try her hand at research. She found her research experience rewarding, especially working with scientists and fellow students and seeing knowledge passed on from person to person. She advises students to find a project that stimulates their curiosity, which will ensure a gratifying and enjoyable experience. Currently, Lorrel is a first-year medical student at Johns Hopkins University. She plans on combining her love of science and medicine to service as a physician who offers care in the United States and travels overseas on medical mercy missions. Lorrel also plays the piano, sings, studies ballet and jazz, volunteers, and tutors. triangle.gif (504 bytes)




Thimerosal, a preservative and anti-microbial agent used in vaccines, ophthalmic solutions, and cosmetics, is a mercury-containing compound that has raised public concern due to its potentially harmful effects. While past studies have implicated mercurial compounds in apoptosis, or programmed cell death, in human T-cells and cells of the central nervous system, no studies have examined the specific effect of thimerosal on neuronal cells, despite evidence that mercurial compounds readily cross the blood-brain barrier. This study examines whether thimerosal induces apoptosis in neuronal cells, and, if so, via which mechanism. To this end, neuronal cells were incubated in the absence and presence of thimerosal at various concentrations for various exposure times and then examined for cell viability, specific morphological changes associated with apoptosis, and changes in the mitochondrial environment. Thimerosal decreased neuronal cell viability in time- and dose-dependent trials, with 90% viability at 2 hr, decreasing to 60% viability at 24 hr (1 mM); at 5 mM thimerosal, viability decreased below 20% at 24 and 48 hr. Thimerosal caused depolarization of the mitochondrial membrane and enhanced superoxide generation. At 5 mM thimerosal, cytochrome c was released from mitochondria to the cytosol in 30% of cells at 1 hr and 85% of cells at 3 hr. Apoptosis-Inducing Factor was released in 40% and 90% of cells at 30 min and 1 hr, respectively. The results suggest that thimerosal causes apoptosis via the mitochondrial pathway and warrant continued efforts to find a replacement compound. triangle.gif (504 bytes)

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Faculty Mentor                                                                                                                

Leman Yel

College of Medicine

Lorrel Brown’s project, which looks into the effect of thimerosal to induce programmed cell death in neuronal cells, shows what an environmental hazardous agent can do in living cells. As such, it draws attention to potential adverse or toxic effects that can be induced by additives readily found in everyday hygiene and cosmetic products, and opens the door to many new and unexplored areas of research. Lorrel’s fascinating work sets an example for what a UCI undergraduate student can achieve through scientific curiosity, motivation, perseverance, and diligence. However, scientific productivity is not the only reward of faculty-mentored undergraduate research. Efficient information processing, analytical and forward thinking are permanent fringe benefits. triangle.gif (504 bytes)

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