Dictionary

pruritus See itching.

pruritic Itchy. For example, a scab may be pruritic.

proximal white subungual onychomycosis See onychomycosis, proximal white subungual.

protozoa A parasitic single-celled organism that can divide only within a host organism. For example, malaria is caused by the protozoa Plasmodium.

proto-oncogene A normal gene that, when altered by mutation, becomes an oncogene that can contribute to cancer. See oncogene.

prothrombin time A test that is done to gauge the integrity of part of the blood clotting process. Prothrombin time is commonly used to screen for bleeding disorders as well as to monitor the accuracy of blood-thinning treatment (anticoagulation) with drugs such as warfarin (brand names: Coumadin, Panwarfin, Sofarin). It measures the time needed for…

prothrombin A coagulation (clotting) factor that is needed for the normal clotting of blood. A cascade of biochemical events leads to the formation of the final clot. In this cascade, prothrombin is a precursor to thrombin. Also known as thrombinogen and simply pro. See also prothrombin time.

Proteus syndrome A disturbance of cell growth that causes overgrowth, asymmetry, and gigantism of bones, limbs, skin, and other organs. Its symptoms also include vascular malformations; raised, rough skin; and overgrowth of fat. John Merrick, the 19th-century Englishman known as the “elephant man,” is thought to have had Proteus syndrome. No specific treatment is available.

proteomics The study of the proteome, the complete set of proteins expressed by an organism, tissue, or cell. It includes the study of changes in protein expression patterns as related to diseases and environmental conditions.

proteinuria See albuminuria.

protein malnutrition See kwashiorkor.

protein-losing enteropathy A condition in which plasma protein is lost excessively to the gastrointestinal tract. Protein-losing enteropathy can be due to diverse causes, including gluten enteropathy, extensive ulceration of the intestine, intestinal lymphatic blockage, or infiltration of leukemic cells into the intestinal wall. Treatment can involve special diets and vitamin supplementation.