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Brown earned his B.A. from the University of Pennsylvania in 1962, and received his M.D. in 1966. After an internship at the Massachusetts General Hospital in Boston (1966-68), he came to the National Institutes of Health as a Clinical Associate and worked in Earl Stadtman's laboratory of biochemistry for three years. In 1971 he was appointed assistant professor at the University of Texas Southwestern Medical School, Dallas, and in 1977 he became professor of genetics and director of the Center of Genetic Diseases.

Brown's research interests have included digestive enzymes, particularly their role in the metabolism of cholesterol. However, he is perhaps best known for his studies of lipid receptors on body cells and their importance in removing cholesterol from the blood. Cholesterol is produced by mammalian cells as well as being taken up into cells from food. It is carried in the bloodstream by proteins called LDLs (low-density lipoproteins. commonly known as "bad cholesterol"). Brown worked on the genetic disease hypocholesterolemia. He found that sufferers from the disease lack a receptor on their cell surfaces to which the LDLs bind, and that this problem results in abnormally high levels of cholesterol in the bloodstream. Brown's research on cholesterol was done in collaboration with Joseph Goldstein, with whom he has had a long and fruitful scientific partnership since 1966. In 1984 Brown and Goldstein elucidated the gene sequence which codes for the LDL receptor, and opened up the possibility of synthesizing drugs to control cholesterol metabolism. They were jointly awarded the 1985 Nobel Prize in Physiology or Medicine.

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Lipmann was educated at the Universities of Königsberg and Berlin, earning his M.D. in 1922 and his Ph.D. in 1927. He then worked with Otto Meyerhof in Heidelberg and taught at the Kaiser Wilhelm Institute in Berlin (1927-31), but with the rise of the Nazis he decided to accept a position at the Carlsberg Foundation in Copenhagen. In 1939 Lipmann moved to America, where he worked at the Cornell Medical School (1939-41), Harvard (1941-49), and the Massachusetts General Hospital in Boston (1949-57), before becoming professor of biochemistry at the Rockefeller Institute for Medical Research in New York, a post he occupied until his retirement in 1970.

Working on the breakdown of glucose by a particular bacterium in 1937, Lipmann found that a certain oxidation would not proceed without the addition of some phosphate. Later he discovered that adenosine triphosphate (ATP) is the source of the phosphate that delivers the energy. He introduced the controversial "~" symbol to indicate a "high-energy" phosphate bond, representing for example ATP as ADP~P. It was not for this work, however, that Lipmann shared the 1953 Nobel Prize in Physiology or Medicine with Hans Krebs but for his discovery in 1947 of coenzyme A and its importance for intermediary metabolism. While working on the role of phosphate in cell metabolism, Lipmann discovered that a heat-stable factor was acting as a carrier of acetyl (CH3CO-) groups. It could be replaced by any other known cofactor. Lipmann eventually isolated and identified what he termed "cofactor A," or CoA, showing that it contained vitamin B2. He also showed that the two-carbon compound in the Krebs cycle that joined with oxaloacetic acid to form citric acid was in fact acetyl CoA. The coenzyme was soon shown to have wider applications than the Krebs cycle, when in 1950 Feodor Lynen found that it played a key role in the metabolism of fats.

Source

John Daintith, et al. eds. Biographical Encyclopedia of Scientists, 2nd ed. Bristol and Philadelphia: Institute of Physics Publishing, 1994.
Hazel Muir, ed. Larousse Dictionary of Scientists. New York: Larousse, 1994.

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Prusiner received his A.B. in chemistry in 1964 and his M.D. in 1968 from the University of Pennsylvania. Following his internship at the University of California, San Francisco, he came to the National Heart and Lung Institute in 1969 as a Clinical Associate. Working in Earl Stadtman's laboratory, he learned various aspects of the research process in biochemistry: developing assays, purifying macromolecules, documenting a discovery by many approaches, and writing clear manuscripts describing what is known and what remains to be investigated. As he later recalled, his three years at NIH were critical in his scientific education.

In 1972, Prusiner began a residency at the University of California, San Francisco in the department of neurology, where he became interested in a "slow virus" infection called Creutzfeld-Jakob disease (CJD) and the seemingly related diseases—kuru of the Fore people of New Guinea and scrapie of sheep. Prusiner joined the faculty there in 1974 and continued his studies on scrapie. Finally in 1982, he published a paper in which he claimed to have isolated the scrapie-causing agent. This agent, which he termed a "prion," was not like other known pathogens, such as viruses and bacteria, because it consisted only of protein and lacked the nucleic acid having genetic information. Prusiner's paper immediately set off a firestorm of criticism, especially from virologists, but by the mid 1990s, his discovery became widely accepted. For this work, he received the 1997 Nobel Prize in Physiology or Medicine.

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DeWitt Stetten, Jr., informally known as Hans, received his A.B. from Harvard in 1930 and his M.D. from the Columbia University College of Physicians and Surgeons in 1934. After his internship and residency at Bellevue Hospital in New York, he returned to Columbia University to study biochemistry. He received his Ph.D. in 1940. Stetten had taught biochemistry at Columbia for nine years before he was appointed assistant professor in biological chemistry at the Harvard Medical School in 1947. The following year he accepted the position of chief of the division of nutrition and physiology of the Public Health Research Institute of New York City.

In 1954 Stetten came to the National Institute of Arthritis and Metabolic Diseases as director of its intramural research program. Eight years later he left NIAMD to become the first dean of the Rutgers Medical School, but he came back to NIH in 1970 as director of the National Institute of General Medical Sciences. He also served as NIH deputy director for science from 1974 to 1979, and was instrumental in creating the NIH's Museum of Medical Research in 1987. The museum was named after him.

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