| radioactive thyroxine | Thyroxine in which a radioisotope of iodine (125I or 131I) is incorporated into its molecule; used in experiments tracing the metabolism of thyroxine. Synonym: labelled thyroxine, radiolabelled thyroxine, radiothyroxin. (05 Mar 2000) |
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| radiolabelled thyroxine | Thyroxine in which a radioisotope of iodine (125I or 131I) is incorporated into its molecule; used in experiments tracing the metabolism of thyroxine. Synonym: labelled thyroxine, radiolabelled thyroxine, radiothyroxin. (05 Mar 2000) |
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| hormone, thyroxine | A chemical substance made by the thyroid gland the thyroid gland uses iodine to make thyroid hormones. Thyroxine (t4), one of the most important thypoid hormones, has four iodine molecules attached to its molecular structure. (12 Dec 1998) |
| thyroxine | <drug, endocrinology> Thyroid hormone. (18 Nov 1997) |
| thyroxine-binding globulin | An alpha-globulin of blood with a strong binding affinity for thyroxine; triiodothyronine is bound to it much less firmly; a deficiency or excess of this protein may occur as a rare benign X-linked disorder. Synonym: thyroxine-binding protein. (05 Mar 2000) |
| thyroxine-binding protein | An alpha-globulin of blood with a strong binding affinity for thyroxine; triiodothyronine is bound to it much less firmly; a deficiency or excess of this protein may occur as a rare benign X-linked disorder. Synonym: thyroxine-binding protein. (05 Mar 2000) |
| thyroxine-binding proteins | A group of proteins that includes thyroxine-binding globulin, a glycoprotein that serves as the major and specific carrier of thyroxine in plasma, accounting for 70-75% of the bound thyroxine; thyroxine-binding prealbumin, an albumin that serves as the secondary carrier, accounting for between 20 and 25% of the bound thyroxine; and serum albumin, which accounts for the remaining bound thyroxine. (12 Dec 1998) |
| thyroxine sodium | A preparation obtained by the action of a limited amount of sodium carbonate upon thyroxine; it contains between 61 and 65% of iodine. See: sodium levothyroxine, sodium liothyronine. (05 Mar 2000) |
| labelled thyroxine | Thyroxine in which a radioisotope of iodine (125I or 131I) is incorporated into its molecule; used in experiments tracing the metabolism of thyroxine. Synonym: labelled thyroxine, radiolabelled thyroxine, radiothyroxin. (05 Mar 2000) |
| free thyroxine index | An arbitrary value obtained by multiplying the triiodothyronine uptake by the serum thyroxine concentration; it largely corrects for variations in thyroid-bound globulin concentration by providing a clinically valid estimate of the physiologically active free thyroxine; direct assay or laboratory measurement of free serum thyroxine yields a more accurate value. (05 Mar 2000) |
| air pollutants, radioactive | Pollutants, present in air, which exhibit radioactivity. (12 Dec 1998) |
| radioactive | Giving off radiation. (12 Dec 1998) |
| radioactive atom | <chemistry, physics> An atom with an unstable nucleus, which emits particulate or electromagnetic radiation (radioactive emission) to achieve greater stability. See: radionuclide, half-life, Becquerel. (05 Mar 2000) |
| radioactive constant | <physics, radiobiology> The fraction of the amount of a radionuclide that undergoes transition per unit time. Formally: Lamda=dP/dt Where dP is the probability of a given nucleus undergoing spontaneous nuclear transition in the time interval dt. (16 Dec 1997) |
| radioactive contamination | <radiobiology> Radioactive substance dispersed in material or places where it is undesirable. (16 Dec 1997) |
| radioactive cow | Colloquialism for radionuclide generator. See: cow. (05 Mar 2000) |