Iodine

About: Iodine is a research topic. Over the lifetime, 8936 publications have been published within this topic receiving 139981 citations. The topic is also known as: I & element 53.

Antithyroid effects of lithium.

Abstract: Lithium has been reported to be goitrogenic when used for the treatment of manic-depressive psychosis. To investigate the effects of lithium on iodine metabolism, male Sprague-Dawley rats were placed on a low iodine (LID) or normal iodine diet (NID) containing enough Li(2)CO(3) to give serum lithium levels of 0.23-0.86 mEq/liter (human therapeutic range is 0.6-1.6 mEq/liter). The following effects were noted with lithium treatment: (a) thyroid weight increased concomitant with a slowing of thyroidal iodine release; (b) the ability to concentrate iodide was increased only after goiters were established; (c) on the LID, (131)I uptake was elevated throughout all phases of treatment, even when the release rate was normal; (d) iodine organification was unaffected but the proportion of (131)I present as iodothyronines was decreased; (e) the thyroidal (127)I content was increased; (f) despite these changes, the serum PBI remained normal as did the thyroxine turnover rate; and (g) thyrotropin (TSH) levels in serum were the same as controls except for a slight elevation early in the course of treatment; TSH levels did not correlate with goitrogenesis. When LiCl was injected in large doses into intact rats (giving serum lithium levels of 3.08-3.89 mEq/liter), the iodide concentrating mechanism, (131)I uptake, and (131)I release rates were depressed. Similar experiments in hypophysectomized rats receiving TSH demonstrated these to be local antithyroid effects not mediated through the pituitary. The discrepancy between acute and chronic responses to lithium, and the dissociation between the inhibition of iodine release and stimulatory effects is discussed.

Age- and sex-adjusted iodine/creatinine ratio. A new standard in epidemiological surveys? Evaluation of three different estimates of iodine excretion based on casual urine samples and comparison to 24 h values.

Abstract: Objective: The most accurate way to measure urinary iodine excretion in epidemiological surveys is still debated. We propose a new principle of estimating iodine excretion based on casual urine samples. Material and methods: A total of 123 24 h urine samples and corresponding casual urine samples were collected from 31 subjects. Iodine excretion was expressed as 24 h iodine excretion and three different estimates: iodine concentration in the casual sample, iodine=gram creatinine in the casual sample, and the new principle — iodine=creatinine ratio in the casual sample, adjusted for expected creatinine excretion of the individual. Results: All three estimates based on casual urine samples correlated significantly to 24 h values with a r (Pearson) of 0.37 for iodine concentration, 0.61 for iodine=creatinine ratio and 0.62 for the age- and sex-adjusted iodine=creatinine ratio. The median iodine excretion in the entire group was 143mg=day in 24 h samples, 87mg=l as iodine concentration, 77mg=g creatinine as iodine=creatinine ratio and 126mg=day as age- and sex-adjusted iodine=creatinine ratio. Conclusion: Age- and sex-adjusted iodine=creatinine ratio is a more accurate and unbiased estimate of iodine excretion in epidemiological surveys of adults than the two most frequently used estimated: iodine concentration and iodine=gram creatinine, as these two estimates may introduce a bias depending on the composition of the investigated group. The adjusted iodine=creatinine ratio is superior to the other estimates, especially when individual estimates of 24 h iodine excretion is required or cohorts of selected groups are investigated. Sponsorship: This work was supported by grants from the Medical Research Foundation Region Greater Copenhagen, Faroe Islands and Greenland; the Wedell-Wedellsborg Foundation; Musikforlaeggerne Agnes and Knut Morks Foundation. Descriptors: iodine; urine; methods; epidemiology; evaluation studies European Journal of Clinical Nutrition (2000) 54, 361‐363

Identification and characterization of a putative human iodide transporter located at the apical membrane of thyrocytes.

Abstract: Iodide transport by thyrocytes is a two step process involving transporters located either in the basal or in the apical membranes of the cell. The sodium iodide symporter (NIS) is localized in the basolateral membrane facing the bloodstream and mediates iodide accumulation into thyrocytes. Pendrin has been proposed as an apical transporter. In order to identify new iodide transporters, we developed a PCR cloning strategy based on NIS sequence homologies. From a human kidney cDNA library, we characterized a gene, located on chromosome 12q23, that encodes a 610 amino acid protein sharing 46% identity (70% similarity) with the human NIS. Functional analysis of the protein expressed in mammalian cells indicates that it catalyzes a passive iodide transport. The protein product was immunohistochemically localized at the apical pole of the thyroid cells facing the colloid lumen. These results suggest that this new identified protein mediates iodide transport from the thyrocyte into the colloid lumen through the apical membrane. It was designated hAIT for human Apical Iodide Transporter.

Association between dietary iodine intake and prevalence of subclinical hypothyroidism in the coastal regions of Japan.

Abstract: The prevalence of thyroid dysfunction in relation to iodine intake was studied in adults (n = 1061) in five coastal areas of Japan that produce iodine-rich seaweed (kelp). The prevalence of hyperthyroidism (TSH 5.0 mU/L) varied from 0-9.7%. The relative frequency of above normal iodide concentration in the morning urine (> or = 75 mumol/L) [high urinary iodide (UI)] varied from 3.7%-30.3%. Together with previously reported results of a noncoastal city, the frequency of high UI correlated significantly with that of hypothyroidism with negative thyroid autoantibody (r = 0.829, n = 6, P < 0.05) but not with positive thyroid autoantibody (r = 0.278, NS) or with that of hyperthyroidism (r = 0.038, NS). Hypothyroidism was more prevalent in thyroid autoantibody-negative subjects with high UI (group II, 12.1%) than with normal UI (group I, 2.3%) (P < 0.001). The TSH [21.9(6.5-73.7)mU/L] (mean +/- SD) and thyroglobulin [288 (182-456) micrograms/L] levels in group II were significantly higher than the respective levels in group I [9.6(3.7-25.3)mU/L and 123 (38-399) micrograms/L] (P < 0.05). Free T4 of group II (9.9 +/- 3.9 pmol/L) was significantly lower than in group I (14.2 +/- 3.9 pmol/L) (P < 0.05). These results indicate that 1) the prevalence of hypothyroidism in iodine sufficient areas may be associated with the amount of iodine ingested; 2) hypothyroidism is more prevalent and marked in subjects consuming further excessive amounts of iodine; and 3) excessive intake of iodine should be considered an etiology of hypothyroidism in addition to chronic thyroiditis in these areas.

Chalcogenide Aerogels as Sorbents for Radioactive Iodine

Abstract: Iodine (129I and 131I) is one of the radionuclides released in nuclear fuel reprocessing and poses a risk to public safety due to its involvement in human metabolic processes. In order to prevent the release of hazardous radioactive iodine into the environment, its effective capture and sequestration is pivotal. In the context of finding a suitable matrix for capturing radioactive iodine, several sulfidic chalcogels were explored as iodine sorbents including NiMoS4, CoMoS4, Sb4Sn3S12, Zn2Sn2S6, and K0.16CoSx (x = 4–5). All of the chalcogels showed high uptake, reaching up to 225 mass % (2.25 g/g) of the final mass owing to strong chemical and physical iodine–sulfide interactions. Analysis of the iodine-loaded specimens revealed that the iodine chemically reacted with Sb4Sn3S12, Zn2Sn2S6, and K0.16CoSx to form the metal complexes SbI3, SnI4, and, KI, respectively. The NiMoS4 and CoMoS4 chalcogels did not appear to undergo a chemical reaction with iodine since iodide complexes were not observed with these s...