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peptide

(Encyclopedia)peptide, organic compound composed of amino acids linked together chemically by peptide bonds. The peptide bond always involves a single covalent link between the α-carboxyl (oxygen-bearing carbon) o...

gigantism

(Encyclopedia)gigantism, condition in which an animal or plant is far greater than normal in size. Plants are often deliberately bred to increase their size. However, among animals, gigantism is usually the result ...

dwarfism

(Encyclopedia)dwarfism, condition in which an animal or plant is less than normal in size and lacks the capacity for normal growth. Dwarfism is deliberately produced and perpetuated in certain species (e.g., in bre...

corticosteroid drug

(Encyclopedia)corticosteroid drug kôrˌtəkōstârˈoid [key], any one of several synthetic or naturally occurring substances with the general chemical structure of steroids. They are used therapeutically to mimic...

ectoderm

(Encyclopedia)ectoderm, layer of cells that covers the surface of an animal embryo after the process of gastrulation has occurred. This outer layer, together with the endoderm, or inner layer, is present in all ear...

secretion

(Encyclopedia)secretion, in biology, substance elaborated by the living material of an animal or plant. Secretions in humans can be produced by a single cell or by a group of cells commonly called a gland. Some sec...

Cushing, Harvey Williams

(Encyclopedia)Cushing, Harvey Williams, 1869–1939, American neurosurgeon, b. Cleveland, B.A. Yale, 1891, M.D. Harvard, 1895. Associated with Johns Hopkins (1896–1912), Harvard (1912–32), and Yale (1933–37),...

blackhead

(Encyclopedia)blackhead, yellowish or blackish plug of material accumulated in the duct of a sebaceous gland. The material consists of keratin (horny cells of the epidermis) and modified sebum (oily secretions of t...

Kendall, Edward Calvin

(Encyclopedia)Kendall, Edward Calvin, 1886–1972, American biochemist, b. South Norwalk, Conn., grad. Columbia (B.S., 1908; Ph.D., 1910). At St. Luke's Hospital, New York City, he did research on the thyroid gland...

estrogen

(Encyclopedia)CE5 estrogen ĕsˈtrəjən [key], any one of a group of hormones synthesized by the reproductive organs and adrenal glands in females and, in lesser quantities, in males. The estrogens cause the th...