Biomedical Engineering Reference
In-Depth Information
Glossary
Arachidonic acid (AA, sometimes ARA): A polyunsaturated omega-6
fatty acid 20:4(!-6). It is the counterpart to the saturated arachidic acid
found in peanut oil. In chemical structures, arachidonic acid is a carboxylic
acid with a 20-carbon chain and four cis-double bonds; the first double
bond is located at the sixth carbon from the omega end. Some chemistry
sources dene \arachidonic acid" to designate any of the eicosatetraenoic
acids. However, almost all writings in biology, medicine, and nutrition
limit the term to all-cis-5,8,11,14-eicosatetraenoic acid. Arachidonic acid
is a polyunsaturated fatty acid present in the phospholipids (especially
phosphatidylethanolamine, phosphatidylcholine, and phosphatidylinosi-
tides) of membranes of the body's cells, and is abundant in the brain,
muscles, and liver. In addition to being involved in cellular signaling as
a lipid second messenger involved in the regulation of signaling enzymes,
such as PLC-, PLC-, and PKC-, -, and - isoforms, arachidonic acid
is a key inflammatory intermediate and can also act as a vasodilator.
ARO: A poorly differentiated thyroid carcinoma-derived cell line.
CD44: A cell-surface glycoprotein involved in cellcell interactions, cell ad-
hesion, and migration. In humans, the CD44 antigen is encoded by the
CD44 gene on Chromosome 11. CD44 is a receptor for hyaluronic acid
and can also interact with other ligands, such as osteopontin, collagens,
and matrix metalloproteinases (MMPs). CD44 function is controlled by
its post-translational modifications. This protein participates in a wide
variety of cellular functions including lymphocyte activation, recircula-
tion and homing, hematopoiesis, and tumor metastasis. Transcripts for
this gene undergo complex alternative splicing that results in many func-
tionally distinct isoforms.
Bonferroni correction: In statistics, is a method used to counteract the
problem of multiple comparisons. The correction is based on the idea
that if an experimentalist is testing n dependent or independent hypothe-
ses on a set of data, then one way of maintaining the family-wise error
rate is to test each individual hypothesis at a statistical significance level
of 1=n times what it would be if only one hypothesis were tested. So, if it
is desired that the significance level for the whole family of tests should
be (at most) , then the Bonferroni correction would be to conduct each
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