Author                                                                                                                              
 

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Alia Shbeeb

Biological Sciences

Alia Shbeeb says that research has dramatically influenced her career aspirations and perspectives of science, while allowing her to appreciate education and the acquisition of knowledge. One of the primary motivations behind her research project is the possibility that her results will contribute to improving the ability of astronauts to explore space and reduce orthostatic intolerance. Her experience with undergraduate research has helped pave the way toward her goal of pursuing a career in medicine while participating in clinical research. In addition to her academic pursuits, she enjoys playing tennis, swimming, and reading law and medical thriller novels. triangle.gif (504 bytes)

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Abstract                                                                                                                           
 

The objective of this study was to determine the effects of zero gravity on the fundamental calcium handling in vascular smooth muscle. Male Wistar rats were hindlimb unweighted (HU) for 20 days in order to simulate microgravity and its alteration of the cardiovascular system. Next, collection and analysis were performed on the contractile responses of abdominal aortas from both HU and control rats in the presence of various antagonists. HU-treated tissues displayed a reduced contractile response to norepinephrine, which indicates alteration of an a-receptor-mediated second messenger pathway. In addition, voltage-operated calcium channel function and protein mass were substantially reduced in HU-treated tissues, whereas HU-treatment seemed to have no effect on protein kinase C. This HU-induced alteration of voltage-operated calcium channels strongly suggests that reduced cytosolic calcium in HU-treated tissues may be an integral factor in the markedly reduced contractile response of the abdominal aorta to norepinephrine. Further studies are needed to determine cytosolic calcium levels in HU and control tissues and the mechanisms involved in the possible intracellular calcium level reduction.triangle.gif (504 bytes)

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Faculty Mentor                                                                                                                
 
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Ralph Purdy

College of Medicine

Alia Shbeeb has made an important contribution to our understanding of the effects of microgravity on vascular function. Using a rodent model, she showed that microgravity decreases arterial constriction, in part, by impairing the function of voltage-operated calcium channels. Vascular impairment underlies orthostatic intolerance (syncope on standing) experienced by space-adapted astronauts and 500,000 Americans who suffer from this syndrome chronically. Alia’s work points to calcium channels as a potential therapeutic target for the treatment of orthostatic intolerance. Both Alia and I have found it rewarding to work together on this project, and I encourage all students to become involved in faculty-mentored undergraduate research.triangle.gif (504 bytes)

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