| T-L | thoracolumbar; thymus-dependent lymphocyte |
|---|---|
| MBLA | methylbenzyl linoleic acid; mouse-specific bone-marrow-derived lymphocyte antigen |
| CTL | cervico-thoraco-lumbar; control; cytolytic C lymphocyte; cytotoxic T-lymphocyte |
| HLA-LD | human lymphocyte antigen-lymphocyte defined |
| LD | labor and delivery; laboratory data; labyrinthine defect; lactate dehydrogenase; laser Doppler; lear... |
| congenital aplasia of thymus | diGeorge syndrome |
|---|---|
| cortex of thymus | The outer part of a lobule of the thymus; it surrounds the medulla and is composed of masses of closely packed lymphocytes. (05 Mar 2000) |
| hypoplasia of the thymus and parathyroids | Also known as the digeorge syndrome (dgs), this disorder is characterised by (1) low blood calcium levels (hypocalcaemia) due to underdevelopment (hypoplasia) of the parathyroid glands needed to control calcium; (2) underdevelopment (hypoplasia) of the thymus, an organ behind the breastbone in which lymphocytes mature and multiply; and (3) defects of the outflow tracts from the heart. most cases of dgs are due to a microdeletion in chromosome band 22q11.2. A small number of cases have defects in other chromosomes, notably 10p13. Named after the american paediatric endocrinologist angelo digeorge. Another name for dgs is the third and fourth pharyngeal pouch syndrome (since the faulty structures in dgs are embryologically derived from the third and fourth pharyngeal pouches). (12 Dec 1998) |
| thymus | <anatomy> The lymphoid organ in which T lymphocytes are educated, mature and multiply. It is composed of stroma (thymic epithelium) and lymphocytes, almost entirely of the T-cell lineage. In mammals the thymus is just anterior to the heart within the rib cage, in other vertebrates in rather undefined regions of the neck or within the gill chamber in teleost fish. The thymus regresses as the animal matures. (18 Nov 1997) |
| thymus and parathyroids, hypoplasia of | See third and fourth pharyngeal pouch syndrome. (12 Dec 1998) |
| thymus-dependent zone | <anatomy> Mid cortical region of lymph node, area that is particularly depleted of T lymphocytes in thymectomised animals and is referred to as the thymus dependent area. (18 Nov 1997) |
| thymus extracts | Extracts of the thymus that contain specific, but uncharacterised factors or proteins with specific activities; three distinct substances are already known: thymotoxin, thymin and thymosin. (12 Dec 1998) |
| thymus gland | A bilaterally symmetric lymphoid organ situated in the anterior superior mediastinum. Each of its two lobes consists of an outer zone, the cortex, relatively rich in lymphocytes (thymocytes), and an inner zone, the medulla, relatively rich in epithelial cells. The thymus is the site of the production of T-lymphocytes. The thymus reaches its maximal development at about puberty and then undergoes a gradual process of involution resulting in a slow decline of immune function throughout adulthood. (12 Dec 1998) |
| thymus hormones | Humoral factors secreted by the thymus gland. They participate in the development of the lymphoid system and the maturation of the cellular immune response. (12 Dec 1998) |
| thymus hyperplasia | Enlargement of the thymus. A condition described in the late 1940's and 1950's as pathological thymic hypertrophy was status thymolymphaticus and was treated with radiotherapy. Unnecessary removal of the thymus was also practiced. It later became apparent that the thymus undergoes normal physiological hypertrophy, reaching a maximum at puberty and involuting thereafter. The concept of status thymolymphaticus has been abandoned. Thymus hyperplasia is present in two thirds of all patients with myasthenia gravis. (12 Dec 1998) |
| thymus-independent antigen | An antigen that does not require T helper cell activation in order for the host's B-cells to be stimulated. Repeating polymers such as polysaccharides are examples of T-independent antigens. (05 Mar 2000) |
| thymus treatment | Treatment of disease by administration of extracts of thymus gland. (05 Mar 2000) |
| lobules of thymus | Areas of thymic tissue 0.5 to 2 mm in diameter with a cortex and medulla. Synonym: lobuli thymi. (05 Mar 2000) |
| antigens, differentiation, b-lymphocyte | Membrane antigens associated with maturation stages of B-lymphocytes, often expressed in tumours of B-cell origin. (12 Dec 1998) |
| antigens, differentiation, t-lymphocyte | Antigens expressed on the cell membrane of T-lymphocytes during differentiation, activation, and normal and neoplastic transformation. Their phenotypic characterization is important in differential diagnosis and studies of thymic ontogeny and T-cell function. (12 Dec 1998) |