T lymphocyte, cytotoxic A cell that expresses the CD8 transmembrane glycoprotein and is antigen specific. Abbreviated CTL. CTLs are able to search out and kill specific types of infected or abnormal cells. When they find cells carrying the peptide they are looking for, they induce those cells to secrete proteins that attract nearby macrophages (specialized…
T cell lymphoma A disease in which cells in the lymphoid system called T cells (or T lymphocytes) become malignant. T cell lymphomas account for a minority (about 15 percent) of non-Hodgkin lymphomas in the US, with the remainder comprised of malignancies of B lymphocytes. See also lymphoma; non-Hodgkin’s lymphoma.
T cell, peripheral A T cell that is found in the peripheral blood rather than in the lymphatic system.
T cell, CD8+ See T lymphocyte, cytotoxic.
T cell A type of white blood cell that is made in the bone marrow and migrates to the thymus gland, where it matures, differentiates into various types of T cells, and becomes active in the immune system. There are several types of mature T cells. Most of the T cells in the body belong…
T Thymine, one member of the adenine-thymine (A-T) base pair in DNA.
systolic Referring to the time at which ventricular contraction occurs, which is called systole. Systolic pressure is the maximum arterial pressure during contraction of the left ventricle of the heart. In a blood pressure reading, the systolic pressure is typically the first number recorded. For example, in a blood pressure of 120/80 (“120 over 80”),…
systemic-onset juvenile rheumatoid arthritis See arthritis, systemic-onset juvenile rheumatoid.
systemic-onset juvenile chronic arthritis See arthritis, systemic-onset juvenile rheumatoid.
systemic therapy Treatment that reaches cells throughout the body by traveling through the bloodstream.
syringoma A benign (noncancerous) skin tumor that derives from eccrine cells, specialized cells related to sweat glands. The skin lesions of syringoma usually appear during puberty or adult life, and consist of small bumps 1 to 3 mm in diameter that form under the surface of the skin. The most frequent site is the eyelids…
syringe A medical device that is used to inject fluid into, or withdraw fluid from, the body. A medical syringe consists of a needle attached to a hollow cylinder that is fitted with a sliding plunger. The downward movement of the plunger injects fluid; upward movement withdraws fluid. Medical syringes were once made of metal…