Iodine radio

Impregnated Activated Carbon Used to Remove Gaseous Radio-Iodines from Gas Streams... 

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. 

Figure 3. Autoradiograph of radio-iodinated bovine serum albumin (BSA), adsorbed onto glass and subsequently immersed in phosphate-buffered saline for (from left to right) 0, 1, 2, 4, and 16 h. Reproduced from Michaeli et al. (7) with permission of Academic Press.

A sample of iodine-128 was produced in a Szilard-Chalmers reaction by irradiating a sample of ethyl iodide in a neutron source. The radio-iodine was extracted with sodium thiosulfate solution and then counted in a Geiger counter at various time Intervals. Use the tabulated data of t in minutes against C counts/min to find the rate equation and the half time. 

Fourth, they are difficult to measure in body fluids. There are very precise ways of measuring very small quantities, in plasma or urine, of almost all conventional medicines and this has made it possible to make the kinetic measurements we have been considering earlier. Some of the techniques for the big protein medicines are not as reliable. For example, one way of tracing a big molecule s progress through the body is to label it with a radioactive tracer. Biopharmaceuticals can be labelled with, for example, radio-iodine (Iodine-125) which can be counted in samples of plasma or urine. However as proteins are similar or identical to normal proteins they can be metabolised and the label can become part of a metabolite or another breakdown product. Counting the iodine radioactivity in this case will not be measuring the parent molecule alone. 

Radio-iodine, I, diffusely kills thyroid cells resulting in eventual and inevitable hypothyroidism which often makes substitution with thyroxine necessary. Administered as capsules it is an effective oral treatment for hyperthyroidism. Patient should not be pregnant or become pregnant in the month following treatment. Breast-feeding is contraindicated. Painful radiation thyroiditis may occur. 

Fig. 17. Chloramine-T (left) and Iodo-gen (right) reagents, used in radio-iodination reactions.

We thank the Royal Society (UK) for a postdoctoral fellowship (GRM) and the University of Otago for a research grant. We are grateful to Michael Crawford for production of biological artwork, Jesse Gale for technical advice on radio-iodination of proteins, Drs Sarah L. Heath and David S. Larsen for helpful discussions, Drs Sally P.A. McCormick, Stephen Faulkner, and Wolfgang Mohr for critically reading this manuscript, Tanya K. Ronson for her help with the references and Dr Katie Heslop for additional help with manuscript production. 

It is a sad story to tell, but this subtle shape-shifting is all too often invisible to the researcher. We will learn what melatonin does, by studying its radio-iodinated derivative. We will determine the quality of our synthetic analogs by measuring the displacement they make of iodinated melatonin from the melatonin receptor, lodomelatonin is not melatonin. It is a different compound. It has a different biochemistry and a different pharmacology. It is used in melatonin studies only because it can be seen. Melatonin itself is, by its nature, a dark traveler in a dark forest, and we still do not know how to study it directly. 

As part of a radio-iodine treatment for a thyroid problem, a sample of radioactive Nal is injected into a person at 9 00 A.M. on a certain day. The iodide goes almost immediately to the thyroid gland. If the sample has 10,000 cpm when injected, how many cpm will there be at 3 00 P.M. on the same day The half-life of the iodine-128 isotope is 25.08 min. 

Studies using radio-iodinated proteins in the TIRF apparatus permit a direct measurement of the amount adsorbed, thus allowing one to deduce if the quantum yield is also changed on adsorption84). 

Several of the alpha-ethyl analogues of ARIADNE were N,N-dialky lated, and were target compounds for halogenation with radio-iodine or radio-fluorine, for evaluation as potential brain blood-flow indicators. In these studies, all examples followed a common flow diagram. The reaction of the appropriate benzaldehyde... 

But, on the brighter side of the picture, you have a heavy atom here, and this atom is intrinsic to the central activity ofthe compound. So, these materials are naturals for radio-labelling experiments. 2C-I has been made radioactive with radio-iodine, but the most impressive findings have been made with the 3-carbon analog, DOI. 

Glanzmann C, Kaestner F, Horst W. Therapie der Hyperthyreose mit Radioisotopen des Jods Erfahrungen bei iiber 2000 Patienten. [Radio-iodine treatment of hyperthyroidism. Experience in more than 2000 patients.] Klin Wochenschr 1975 53(14) 669-78. 

Jialal I, Pillay NL, Asmal AC. Radio-iodine-induced hypoparathyroidism. A case report. S Afr Med J 1980 58(23) 939-40. 

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). 

Castenfors H, Allgoth AM. The effect of iodochlorohy-droxyquinoline, diiodohydroxyquinoline and dichlorohy-droxyquinaldine on the thyroid uptake of radio-iodine. Scand J Clin Lab Invest 1957 9(3) 270-2. 

Public interest in radioactive aerosols began in the mid-1950s, when world-wide fallout of fission products from bomb tests was first observed. The H-bomb test at Bikini Atoll in 1954 had tragic consequences for the Japanese fisherman, and the inhabitants of the Ronge-lap Atoll, who were in the path of the fallout. In 1957, radio-iodine and other fission products, released in the accident to the Windscale reactor, were tracked over much of Europe, and these events were repeated on a much larger scale after the Chernobyl accident. 

The first step of the analysis ensures isotopic exchange of the stable carrier and the radio-iodine in the sample. In this experiment, iodate carrier is added and then reduced to iodide with sodium sulfite to cause exchange among iodate, iodine, and iodide species. (Read the discussion in the Introduction to the Course on isotopic exchange.) The resulting iodide is purified by precipitation, first as silver iodide (Agl) and then, after dissolution, as palladium iodide (Pdl2). 

To select another eluent to replace perchlorate solution for the displacement of radio-iodine sorbed from milk on an anion exchange resin column in a method that is described in a published article. 

Selected reagents for elution of radio-iodine from anion-exchange resin... 

Step 7. Test your selected eluent in an aqueous system. Prepare a set of identical anion-exchange resin columns according to the article. Prepare a set of identical 1-L samples of tap water. Pipette into each sample 1 mL iodide carrier and 5 mL radio-iodine tracer and mix. Let samples flow through column at flow rate of no more than 5 mL per minute. Prepare 200 mL solutions of the selected eluting agents. 

Step 8. Pass each eluting agent through the resin column at flow of 5 mL per minute. Collect sequential 5-ml fractions of each eluent and measure the radio-iodine net count rate in each eluent fraction. Draw curve of net radioiodine count rate vs. eluted volume. Select the eluting solution that removes radio-iodine from the resin column most effectively, i.e., in the smallest volume. 

Step 10. Repeat Step 8 with the selected most effective eluting solution for the column that retained radio-iodine from milk. 

Report the volume required for 99% elution of radio-iodine, or the percent eluted with 200 mL if 99% elution was not attained. Prepare curve of radioiodine count rate as function of eluent fraction for each type of eluent to compare effectiveness. 

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