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Jehovah's Witnesses

(Encyclopedia)Jehovah's Witnesses, Christian group originating in the United States at the end of the 19th cent., organized by Charles Taze Russell, whose doctrine centers on the Second Coming of Christ. The Witnes...

multiple sclerosis

(Encyclopedia)multiple sclerosis (MS), chronic, slowly progressive autoimmune disease in which the body's immune system attacks the protective myelin sheaths that surround the nerve cells of the brain and spinal co...

midge

(Encyclopedia)midge, name for any of numerous minute, fragile flies in several families. The family Chironomidae consists of about 2,000 species, most of which are widely distributed. The herbivorous larvae are fou...

norepinephrine

(Encyclopedia)norepinephrine nôrˌĕpīnĕfˈrən [key], a neurotransmitter in the catecholamine family that mediates chemical communication in the sympathetic nervous system, a branch of the autonomic nervous sys...

myoglobin

(Encyclopedia)myoglobin mīˌəglōˈbĭn [key], protein molecule isolated from the cells of vertebrate skeletal muscle that is both a structural and functional relative of hemoglobin, the oxygen-transport protein ...

parathyroid hormone

(Encyclopedia)parathyroid hormone or parathormone, a hormone secreted by the parathyroid glands that regulates the metabolism of calcium and phosphate in the body. It has been purified extensively and appears to be...

mastiff

(Encyclopedia)mastiff măsˈtĭf [key], breed of very large, powerful working dog developed in England more than 2,000 years ago. It stands from 27 to 33 in. (68.6–83.8 cm) high at the shoulder and weighs from 16...

Armstrong, Lance

(Encyclopedia)Armstrong, Lance, 1971–, American cyclist, b. Dallas, Tex. He won (1991) the U.S. amateur cycling championship, turned professional (1992), and by the mid-1990s had won the Tour DuPont twice and was...

placebo

(Encyclopedia)placebo pləsēˈbō [key], inert substance given instead of a potent drug. Placebo medications are sometimes prescribed when a drug is not really needed or when one would not be appropriate because t...

caffeine

(Encyclopedia)caffeine kăfēnˈ [key], odorless, slightly bitter alkaloid found in coffee, tea, kola nuts (see cola), ilex plants (the source of the Latin American drink maté), and, in small amounts, in cocoa (se...