| CHARGE | coloboma, heart disease, atresia choanae, retarded growth and retarded development and/or CNS anomal... |
|---|---|
| ACH | acetylcholine; achalasia; active chronic hepatitis; adrenocortical hormone; amyotrophic cerebellar h... |
| AH | abdominal hysterectomy; absorptive hypercalciuria; accidental hypothermia; acetohexamide; acid hydro... |
| PNM | perinatal mortality; peripheral dysostosis, nasal hypoplasia, and mental retardation [syndrome]; per... |
| TD | tabes dorsalis; tardive dyskinesia; T-cell dependent; temporary disability; terminal device; tetanus... |
D factor
| 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) |
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| 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 derived lymphocyte | <haematology, immunology> A class of lymphocytes, so called because they are derived from the thymus and have been through thymic processing. Involved primarily in controlling cell-mediated immune reactions and in the control of B-cell development. The T-cells coordinate the immune system by secreting lymphokine hormones. There are 3 fundamentally different types of t cells : helper, killer, and suppressor. Each has many subdivisions. T-cells are also called t lymphocytes. They bear T-cell antigen receptors (CD3) and lack Fc or C3b receptors. Major T-cell subsets are CD4 (mainly helper cells) and CD8 (mostly cytotoxic or suppressor T-cells). Uncontrolled proliferation of this type of cell gives rise to T-cell leukaemia/lymphoma. (21 Jun 1999) |
| 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) |
| abstracting and indexing | Shortening or summarizing of documents; assigning of descriptors for referencing documents. (12 Dec 1998) |
| academies and institutes | Organizations representing specialised fields which are accepted as authoritative; may be non-governmental, university or an independent research organization, e.g., national academy of sciences, brookings institution, etc. (12 Dec 1998) |
| accounts payable and receivable | Short-term debt obligations and assets occurring in the regular course of operational transactions. (12 Dec 1998) |
| aged, 80 and over | A person 80 years of age and older. (12 Dec 1998) |
| algae and fungi | Algae represent a group of spore-propagating plants, unicellular or undifferentiated into root, stem, and leaf. They include seaweed and many unicellular fresh water plants, most of which contain chlorophyll. They account for about 90% of the earth's photosynthetic activity. Fungi are eukaryotic, heterotrophic organisms that live as saprobes or parasites and include mushrooms, yeasts, smuts, molds, etc. They lack chlorophyll. (12 Dec 1998) |