thrombotic thrombocytopenic purpura A life-threatening disease that involves embolism and thrombosis (plugging) of the small blood vessels in the brain and elsewhere in the body. Abbreviated TTP. TTP is characterized by the presence of platelet microthrombi (tiny traveling clots composed of platelets, the clotting cells in the blood), thrombocytopenia (lack of platelets), hemolytic anemia (from…
thrombus A clot in a blood vessel or within the heart.
thrush A yeast infection of the mucous membranes within the throat and mouth. Thrush looks like a light or white coating on the affected tissue, and it may cause irritation. Thrush is seen most often in infants, young children, elderly people (especially those who wear dentures or take medications that lower output of saliva), and…
thymine One member of the base pair A-T (adenine-thymine) in DNA.
thymiosis See yaws.
thymus An organ that is located in the upper chest behind the breastbone and in front of the lower neck in which the immune cells called T lymphocytes mature and multiply in early life. The thymus begins to shrink after puberty.
thymus and parathyroids, hypoplasia of See DiGeorge syndrome.
thyroglobulin A protein that is found primarily in the thyroid gland. Some thyroglobulin can be found in the blood, and this amount may be measured after thyroid surgery to determine whether thyroid cancer has recurred. Abbreviated Tg.
thyroglossal cyst See cyst, thyroglossal.
therapeutic cloning Cloning designed as therapy for a disease. In therapeutic cloning, the nucleus of a cell, typically a skin cell, is inserted into a fertilized egg whose nucleus has been removed. The nucleated egg begins to divide repeatedly to form a blastocyst. Scientists then extract stem cells from the blastocyst and use them to…
therapy The treatment of disease. Therapy is synonymous with treatment.
thermometer In medicine, a device used to measure the temperature of the human body. There are many types of medical thermometers, including oral thermometers (placed under the tongue), rectal thermometers (placed within the rectum), multipurpose thermometers (placed under the tongue, in the rectum, or under the armpit), eardrum thermometers (placed inside the ear), and basal…