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Interferon was scarce and expensive until 1980, when the interferon gene was inserted into bacteria using recombinant DNA technology, allowing for mass cultivation and purification from bacterial cultures.
Approximately one in three babies in the United States is now delivered by cesarean section. The number of cesarean sections in the United States has risen 46% since 1996.
Cocaine was isolated in 1860 and first used as a local anesthetic in 1884. Its first clinical use was by Sigmund Freud to wean a patient from morphine addiction. The fictional character Sherlock Holmes was supposed to be addicted to cocaine by injection.
The heart is located in the center of the chest, with part of it tipped slightly so that it taps against the left side of the chest.
A cataract is a clouding of the eyes' natural lens. As we age, some clouding of the lens may occur. The first sign of a cataract is usually blurry vision. Although glasses and other visual aids may at first help a person with cataracts, surgery may become inevitable. Cataract surgery is very successful in restoring vision, and it is the most frequently performed surgery in the United States.