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 cell, CD8+ See T lymphocyte, cytotoxic.
T cell, peripheral A T cell that is found in the peripheral blood rather than in the lymphatic system.
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 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…
tabes dorsalis See neurosyphilis, tabes.
tablespoon An old-fashioned but convenient household measure of capacity that is equal to about 15 cc of liquid.
TACE Transarterial chemoembolization, a procedure in which the blood supply to a tumor is blocked (embolized) and chemotherapy is administered directly into the tumor. For example, TACE has been used to treat some liver cancers.
syncope, defecation The temporary loss of consciousness upon defecating (having a bowel movement). See also syncope; syncope, situational; vasovagal reaction.
syncope, micturition The temporary loss of consciousness upon urinating (micturation). See also syncope; syncope, situational; vasovagal reaction.
syncope, situational The temporary loss of consciousness in a particular kind of situation. The situations that trigger this reaction are diverse and include having blood drawn, straining while urinating or defecating, and coughing. The reaction can be caused also by emotional stress, fear, or pain. When experiencing the trigger condition, the person often becomes pale…
syncope, swallowing The temporary loss of consciousness upon swallowing. See also syncope; syncope, situational; vasovagal reaction.