| T-mycoplasma | A microorganism that can infect peoples' bladders, ureaplasmas are similar to mycoplasmas. (09 Oct 1997) |
|---|---|
| t-phages | A series of 7 virulent phages which infect e. Coli. The t-even phages t2, t4 (bacteriophage t4), and t6, and the phage t5 are called "autonomously virulent" because they cause cessation of all bacterial metabolism on infection. Phages t1, t3 (bacteriophage t3), and t7 (bacteriophage t7) are called "dependent virulent" because they depend on continued bacterial metabolism during the lytic cycle. The t-even phages contain 5-hydroxymethylcytosine in place of ordinary cytosine in their DNA. (12 Dec 1998) |
| t-suppressor cell | A type of immune cells, also called t8 cells, these cells close down the immune response after it has destroyed invading organisms. T8 cells are sensitive to high concentrations of circulating lymphokine hormones and release their own lymphokines after an immune response has achieved its goal, signalling all other participants to cease their attack. Some memory B-cells remain to ward off a repeat attack by the invading organism. (12 Dec 1998) |
| T1 | In magnetic resonance, the time for 63% of longitudinal relaxation to occur; the value is a function of magnetic field strength and the chemical environment of the hydrogen nucleus; for protons in fat and in water, in a 1.5T magnet, about 250 msec and 3000 msec respectively. A T1-weighted image will have a bright fat signal. (05 Mar 2000) |
| T2 | In magnetic resonance, the time for 63% of transverse relaxation to occur; the value is a function of magnetic field strength and the chemical environment of the hydrogen nucleus; for protons in fat and in water, in a 1.5T magnet, about 60 msec and 250 msec respectively. A T2-weighted image will have a bright water signal. (05 Mar 2000) |
| t3 | <endocrinology, hormone> One of two main hormones produced by the thyroid gland. Free triiodothyronine is that not bound by thyroid binding globulin in the plasma and the levels are are high in hyperthyroidism, nephrotic syndrome and renal failure and low in acute hepatitis, hypothyroidism and pregnancy. Abbreviation: T3 (27 Sep 1997) |
| T3 uptake test | A test of thyroid function in which triiodothyronine (T3) is added to a patient's serum in vitro to measure the relative affinities of serum proteins and of an added competitive substance for T3; higher T3 uptakes are associated with hyperthyroidism. Synonym: T3 uptake test. (05 Mar 2000) |
| T4 | Thyroxine, a thyroid hormone. (The number 4 is usually in subscript.) thyroid hormones are essential for the function of every cell in the body. They help regulate growth and the rate of chemical reactions (metabolism) in the body. (12 Dec 1998) |
| t4 cell | T helper cells which are targets for HIV infection. (09 Oct 1997) |
| t4 helper lymphocyte | A specific type of lymphocyte, derived from the thymus gland, that plays an important role in cellular immunity. T4 lymphocytes (CD4 cells) are decreased (absolute counts less than 200) in patients with AIDS resulting in compromised immune function. (27 Sep 1997) |
| T5 D15 exonuclease | <enzyme> Highly efficient 5'-3'-exonuclease which possesses additionally a tightly associated single-strand-specific endonuclease activity; used for the destruction of the partially polymerised species and ssdna present in a typical polymerization reaction Registry number: EC 3.1.- (26 Jun 1999) |
| t8 cell | A type of immune cells, T8 cells close down the immune response after it has destroyed invading organisms. T8 cells are sensitive to high concentrations of circulating lymphokine hormones and release their own lymphokines after an immune response has achieved its goal, signalling all other participants to cease their attack. Some memory B-cells remain to ward off a repeat attack by the invading organism. T8 cells are also called t-suppressor cells. (12 Dec 1998) |
| Ta | Symbol for tantalum. (05 Mar 2000) |
| TAB vaccine | A suspension of killed typhoid and paratyphoid A and B bacilli. See: typhoid vaccine. Synonym: TAB vaccine. (05 Mar 2000) |
| tabanid | Common name for flies of the family Tabanidae. Origin: L. Tabanus, gadfly (05 Mar 2000) |