North America is a continent in the Earth's northern hemisphere and almost fully in the western hemisphere, bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the south and west by the North Pacific Ocean; South America lies to the southeast. It covers an area of about 24,480,000 km2 (9,450,000 sq mi), or about 4.8% of the planet's surface. As of July 2002, its population was estimated at more than 514,000,000. It is the third largest continent in area, after Asia and Africa, and is fourth in population after Asia, Africa, and Europe.
Etymology
A number of theories exist regarding the naming of North and South America. The most widely recognized is that they are named after Amerigo Vespucci, who was the first European to suggest that the Americas were not the East Indies, but a New World, previously undiscovered by Europeans. The second and less generally accepted is that the continents are named after an English merchant named Richard Amerike from Bristol, who is believed to have financed John Cabot's voyage of discovery from England to Newfoundland in 1497. A third and minutely explored belief that has been advanced is that America was named for a Spanish sailor bearing the ancient Visigothic name of 'Amairick'.
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[Mini-Review] Utility of Kallikrein-Related Peptidases (KLKs) as Cancer Biomarkers Emami, N., Diamandis, E. P. Mon, 29 Sep 2008 00:00:00 -0000
Background: The human kallikrein-related peptidase (KLK) family consists of 15 highly conserved serine proteases, which are encoded by the largest uninterrupted cluster of protease genes in the human genome. To date, several members of the family have been reported as potential cancer biomarkers. Although primarily known for their biomarker value in prostate, ovarian, and breast cancers, more recent data suggest analogous roles of KLKs in several other cancers, including gastrointestinal, head and neck, lung, and brain malignancies. Among the proposed KLK cancer biomarkers, prostate-specific antigen (also known as KLK3) is the most widely recognized member in urologic oncology.
Content: Despite substantial progress in the understanding of the biomarker utility of individual KLKs, the current challenge lies in devising biomarker panels to increase the accuracy of prognosis, prediction of therapy, and diagnosis. To date, multiparametric KLK panels have been proposed for prostate, ovarian, and lung cancers. In addition to their biomarker utility, emerging evidence has revealed a number of critical functional roles for KLKs in the pathogenesis of cancer and their potential use as therapeutic targets.
Summary: KLKs have biomarker utility in many cancer types but individually lack sufficient specificity or sensitivity to be used in clinical practice; however, groups of KLKs and other candidate biomarkers may offer improved performance.
[Mini-Review] High-Abundance Polypeptides of the Human Plasma Proteome Comprising the Top 4 Logs of Polypeptide Abundance Hortin, G. L., Sviridov, D., Anderson, N. L. Mon, 29 Sep 2008 00:00:00 -0000
Background: Plasma contains thousands of proteins, but a small number of these proteins comprise the majority of protein molecules and mass.
Content: We surveyed proteomic studies to identify candidates for high-abundance polypeptide chains. We searched the literature for information on the plasma concentrations of the most abundant components in healthy adults and for the molecular mass of the mature polypeptide chains in plasma. Because proteomic studies usually dissociate proteins into polypeptide chains or detect short peptide segments of proteins, we summarized data on individual peptide chains for proteins containing multiple subunits or polypeptides. We collected data on about 150 of the most abundant polypeptides in plasma. The abundant polypeptides span approximately the top 4 logs of concentration in plasma, from 650 to 0.06 µmol/L on a molar basis or from about 50 000 to 1 mg/L mass abundance.
Conclusions: Data on the concentrations of the high-abundance peptide chains in plasma assist in understanding the composition of plasma and potential approaches for clinical laboratory or proteomic analysis of plasma proteins. Development of more extensive databases regarding the plasma concentrations of proteins in health and diseases would promote diagnostic and proteomic advances.