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Author |
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Alia Shbeeb
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Biological
Sciences
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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. 
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Abstract |
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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.
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Faculty
Mentor |
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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.
Alias 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.
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Copyright ©
2001 by the Regents of the University
of California. All rights reserved.
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