Radioiodines

G. J. Raab md co-workers. Operating Experience Using Silver Reactors for Radioiodine Removal in the Hanford Purex Plant, ARH-SA-67, Atimtic Richfield Hmford Co., Richlmd, Wash., June 1970. 

Thyroid Uptake Systems. Studies involving absolute thyroid uptake can be performed without imaging using small amounts of or and a simple scintillation probe. This is caUbrated using a phantom, ie, a model of a portion of the human body, loaded with the isotope being used. This instmment is also useful for assaying thyroid exposure to radioiodine among personnel. 

Using any of the carrier proteins available in highly purified form, eg, TBG or TBPA, a convenient and accurate quantitative determination of and is possible by displacement of radioiodinated or T. This procedure enables their quick determination at low concentrations even in the presence of coundess other substances that occur in body duids (31). In a similar fashion, intact cell nuclei or solubilized proteins from rat fiver cell nuclei, which display high affinities for thyroid hormones, especially T, have been used to establish relative binding affinities of many thyromimetic compounds (7). 

The selective uptake of iodide ion by the thyroid gland is the basis of radioiodine treatment in hyperthyroidism, mainly with although various other radioactive isotopes ate also used (40,41). With a half-life of eight days, the decay of this isotope produces high energy P-particles which cause selective destmction within a 2 mm sphere of their origin. The y-rays also emitted are not absorbed by the thyroid tissue and are employed for external scanning. 

Radioiodine Testing of Nuclear-Grade Gas-Phase Adsorbents pH of Activated Carbon... 

However, the dry deposition rate for noble gases, tritium, carbon-14, and nonelemental radioiodine is so slow that this depletion mechanism is negligible within 50 miles of the release point. Elemental o radioiodine and other particulates are readily deposited. This transfer can be quantified as a transfer velocity (where concentration transfer velocity = deposition rate). The transfer velocity is proportional to windspeed and, as a consequence, the rate of depositirm is independent of windspeed since concentration in air is inversely proportional to windspeed. 

Radiation Therapeutic Radioiodine Atomic fallout infections Rubella virus Cytomegalovirus Herpes virus homlnis Toxoplasmosis... 

Astatine has been shown to be superior to radio-iodine for the destruction of abnormal thyroid tissue (p. 794) because of the localized action of the emitted a-particles which dissipate 5.9 MeV within a range of 70 fim of tissue, whereas the much less energetic /S-rays of radioiodine have a maximum range of ca. 2(K)0 fim. However, its general inaccessibility and high cost render its extensive application unlikely. 

Treatment with radioiodine or surgery If relapse after 1 year of antithyroid drug treatment After euthyroid ism is achieved... 

Radioiodinated derivatives have been prepared to define more closely the target site of a-conotoxins on the acetylcholine receptor (R. Myers, unpublished data). In membrane preparations from Torpedo electroplax, photoactivatable azidosalicylate derivatives of a-conotoxin GIA preferentially label the p and 7 subunits of the acetylcholine receptor. However, when the photoactivatable derivative is cross-linked to detergent solubilized acetylcholine receptor (AChR), only the 7 subunit is labeled. Since snake a-neurotoxins mainly bind to the a subunits of AChR and a-conotoxins compete directly with a-bungarotoxin, the cross-linking results above are both intriguing and problematic. 

Increased radioiodine uptake in the thyroid indicates increased hormone production by the thyroid gland. 

Gatley SJ, Gilford AN, Volkow ND, Lan R, Makriyannis A. Iodine-123 labeled AM251 a radioiodinated ligand which binds in vivo to the mouse brain CB1 cannabinoid receptor. Eur J Pharmacol 1996 307 301-308. 

The processes of both seed formation and fibril extension are dependent on temperature and on peptide concentration, with 37°C being required for establishing equilibrium within 24 h with 30 pM Pi 4o- A full description of the assay system may be found elsewhere [97,117], A 4 h reaction time is typically within the linear portion of the time course. This nucleus-dependent assay detects mainly inhibitors that are substoichiometric with the monomeric peptide, which is present at high concentration. It is relatively insensitive to inhibitors that target the monomeric peptide. Whether the inhibitors interact with the growing end of a seed or with a low abundance conformational form of the p peptide that is competent to add to the seed is difficult to determine at this time. Similar dose-response curves are obtained for Congo Red as an inhibitor with either thioflavin T (ThT) fluorescence or filtration of radioiodinated peptide readouts (Fig. 4) Caveats in the interpretation of both the ThT and radiometric filtration assays for the evaluation of putative inhibitors are discussed elsewhere [97]. 

Barry, P.J., Sampling for Airborne Radioiodine by Copper Screens, Health Phys. 15 243-250 (1986). 

Chattopadhyay et al., 1992), and a comparison of radiolabeling techniques for the crosslinker (Shephard et al., 1988). Other studies have involved the investigation of protein interactions using the label transfer nature of radioiodinated SASD (Gupta et al., 2005 Lindersson et al., 2005 LeFebvre et al., 2006). 

Radioiodination is the process of chemically modifying a molecule to contain one or more atoms of radioactive iodine. Early studies on protein modification determined that iodine in... 

The prevailing procedures for direct coupling of 125I to a protein or other molecule are through the use of oxidizing agents. The in situ preparation of an electrophilic radioiodine... 

The following sections discuss the major radioiodination reagents available for direct labeling as well as the main crosslinkers or modification reagents used for indirect labeling techniques. 

Chloramine-T, or N-chlorotoluenesulfonamide, has been one of the most popular oxidizing reagents used for radioiodination techniques since its introduction by Greenwood et al. in 1963 (Sigma). It has strong oxidizing properties that readily lead to the formation of the required... 

---