Radio-potassium

As an example consider the exchange reaction between benzyl iodide and free iodide ions, Eq. (3-43).6 Mixing ethanolic solutions of benzyl iodide and radio-labeled potassium iodide started the isotopic exchange. At different times, samples were withdrawn and added to a benzene-water mixture, causing separation into two layers. The aqueous layer contained the iodide ions, and the organic layer contained the benzyl iodide. The activity of 1311 was determined in each layer. 

Such mechanisms might be questioned since in a recent work Goodman and Arnon (55) demonstrated the absence of initiator s fragments in the resulting polymer. In the course of their studies, polymerisation of y-benzyl-i.-glutamate was initiated in dioxane by 9-fluorenyl potassium or by radio-active sodium methoxide. The polymer produced by the former initiator was precipitated and examined spectrophotometrically. For Mjl ratio of 60 its degree of polymerisation was found from its intrinsic viscosity, to be about 180 and its solution did not absorb at A = 300 mfi where a strong absorption band (e = 104) of the fluorenyl moiety should appear. On the other hand, all the fluorenyl residues were found in the solution left after precipitation of the polymer. 

The treatment of amiodarone-induced hyperthyroidism is difficult. It often does not respond to conventional therapy with carbimazole, methimazole, or radio-iodine. However, corticosteroids and the combination of methimazole with potassium perchlorate have been reported to be effective (52), even if amiodarone is continued (53). Other regimens that have been used include combinations of corticosteroids with carbimazole (54), corticosteroids and benzylthiouracil (55), or propylthiouracil (SEDA-15, 170). Potassium perchlorate has also been used (SEDA-21, 199). Other forms of treatment that have been successful have been plasma exchange and in very severe cases subtotal thyroidectomy (56) or total thyroidectomy (SEDA-15,170 SEDA-17, 220 57). 

The main modification for practical use in endocrine safety pharmacology is the application of this method to satellite groups of animals in a repeated dose study. Most pelleted animal feeds nowadays contain a standard amount of iodine (it may be useful to check the specification). Therefore, the addition of potassium iodine to the drinking water is not required. In this satellite groups, the animals are injected with a standard dose of radio-iodine after the last treatment, and the dose of radioactivity accumulated in the thyroid glands after a standard time interval (e.g. two hours) is determined and evaluated. 

In one assay developed to measure this activity, ion-paired reversed-phase HPLC (Cis) was used to separate the reactants from the products. The mobile phase was 0.065 M potassium phosphate with 1 mM tetrabutylammonium phosphate adjusted to pH 3.6 with phosphoric acid and 3% acetonitrile. The column was eluted isocratically and monitored at 254 nm and with a radio-... 

With the exception of some early potassium-argon ages of nearly 5 Ga, and which are believed to be analytical artifacts, aU high quality radio-metric ages of CAIs are no older than 4.56-4.57 Ga. This observation suggests that whole CAIs are not themselves presolar objects, although it does not rule out the possibility that presolar CAI precursors were reprocessed (melted or otherwise completely recrystallized) in the earliest solar system. For more on CAI chronology, see Chapter 1.16. 

Figure 4. Radio-HPLC chromatograms showing accumulation of CoA esters from [U- C]hexadecanoyl-CoA by rat heart mitochondria in the presence of (A) 0,(C) 2mM potassium maleate. Rat heart mitochondria were incubated with 90 xM [U- Clhexadecanoyl-CoA and CoA esters analysed by radio HPLC. The chromatograms are representative of 3-S incubations. Peak identification 1, TCA cycle intermediates, 2, acetyl- 3, dec-2-enoyl- 4, 3-hydroxydodecanoyl- 5, decanoyl- 6, dodec-2-enoyl- 7, 3-hydroxytetradecanoyl- ...

In an NMR experiment, transitions are induced between these levels with radio frequency fields applied at or near the resonant frequency a o (Abragam, 1961 Slichter, 1990). The alkali metals are good candidates for NMR experiments because there are a number of abundant, stable nuclear isotopes, Li, Li, Na, Rb, Rb, and Cs. The exception is potassium the isotope possesses only a weak magnetic moment and occurs with low natural abundance. 

R. Gupta, W. Happer, L. Lam, S. Svanberg Hyperfine structure measurements of excited S states of the stable isotopes of potassium, rubidium and cesium by cascade radio-frequency spectroscopy. Phys. Rev. A8, 2792 (1973)... 

Orlova, A., Bruskin, A., Sivaev, I. et al. 2006. Radio-iodination of monoclonal antibody using potassium... 

Iodized Oil Iodine in poppy seed oil-lipiodol is extensively used in radiology as a radio-contrast medium to demonstrate holes (cavities) in the lung. Available both by injection (lipiodol) and by mouth (oriodol) for the instant correction of iodine deficiency Iodized Salt Salt to which potassium iodate or potassium iodide has been added at a recommended level of 20—40 milligrams of iodine per kilogram of salt Kiwanis International A World Service Group including more than 10,000 clubs and over 500,000 members based in the USA... 

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