Showing papers on "Iodine published in 2003"
676 citations
TL;DR: In this article, a dual-fortified salt (DFS) containing iodized salt and micro-encapsulated iron was developed and tested in a series of studies in northern Morocco.
160 citations
TL;DR: In this paper, the iodide anion was adsorbed preferentially onto Pt co-catalyst as iodine atom, I. This iodide layer effectively suppressed the backward reaction of water formation from H 2 and O 2 to H 2 O over the Pt surface.
158 citations
TL;DR: In this paper, a new high performance liquid chromatography (HPLC) method was developed for the determination of iodine speciation, using anion exchange chromatography and spectrophotometry.
142 citations
TL;DR: Results show that higher concentrations of I(-) (> or =10 microM) had some detrimental effect on plant growth, while IO(3)(-) had little effect on the biomass production of spinach plants.
140 citations
TL;DR: Elimination of iodine deficiency in areas affected by Chernobyl may be important in reducing the effects of radiation exposure on the thyroid, and may have implications for the use of stable iodine in the case of population exposure to radioactive iodine.
Abstract: Background: Little is known about the joint effect of iodine deficiency and radiation exposure on the risk of thyroid cancer. No epidemiological studies have been published assessing the modifying effect of iodine deficiency on radiation-induced thyroid cancer following the Chernobyl accident. Methods: A population sample of 3070 individuals (2590 ages 6–18 and 480 adults) from 75 settlements in the most highly contaminated regions of the Bryansk Oblast of Russia was identified and sampled for urinary iodine measurements in 1996 and iodine deficiency in each geopolitical unit (raion) was estimated. All cases of thyroid cancer were identified in those born 1968–1986 who were resident in the study area in May–June 1986 (34 histologically confirmed cases). The risk of thyroid cancer was examined in relation to population estimates of thyroid radiation dose and urinary iodine excretion level. Results: The excess relative risk (ERR) of thyroid cancer was significantly associated with increasing thyroid radiation dose and was inversely associated with urinary iodine excretion levels. There was a joint effect of radiation exposure and iodine deficiency. At 1 gray (Gy) the ERR in territories with severe iodine deficiency was approximately two times that in areas of normal iodine intake. Conclusions: These findings suggest that elimination of iodine deficiency in areas affected by Chernobyl may be important in reducing the effects of radiation exposure on the thyroid. If confirmed by studies based on individuals they may have implications for the use of stable iodine in the case of population exposure to radioactive iodine. (authors)
126 citations
TL;DR: A colorimetric method is evaluated which detects the activity of endogenous peroxidases by their reaction with hydrogen peroxide, using tetramethylbenzidine as the chromogenic substrate, and was able to find an explanation for the increased total antioxidant status in the presence of iodide.
112 citations
TL;DR: The role played in thyroid hormonogenesis by iodide oxidation to iodine (organification) is well established and less compelling evidence exists of a role for iodide as an antioxidant in the breast.
Abstract: The role played in thyroid hormonogenesis by iodide oxidation to iodine (organification) is well established. Iodine deficiency may produce conditions of oxidative stress with high TSH producing a level of H2O2, which because of lack of iodide is not being used to form thyroid hormones. The cytotoxic actions of excess iodide in thyroid cells may depend on the formation of free radicals and can be attributed to both necrotic and apoptotic mechanisms with necrosis predominating in goiter development and apoptosis during iodide induced involution. These cytotoxic effects appear to depend on the status of antioxidative enzymes and may only be evident in conditions of selenium deficiency where the activity of selenium containing antioxidative enzymes is impaired. Less compelling evidence exists of a role for iodide as an antioxidant in the breast. However the Japanese experience may indicate a protective effect against breast cancer for an iodine rich seaweed containing diet. Similarly thyroid autoimmunity may also be associated with improved prognosis. Whether this phenomenon is breast specific and its possible relationship to iodine or selenium status awaits resolution.
102 citations
TL;DR: Iodine in soils is methylated and volatilized as CH3I by the action of soil bacteria and that iodine-volatilizing bacteria are ubiquitous in soil environments, suggesting the pathway of iodine volatiles by soil bacteria should be important for understanding the biogeochemical cycling of iodine.
Abstract: The roles of microorganisms in iodine volatilization from soils were studied. Soils were incubated with iodide ion (I-), and volatile organic iodine species were determined with a gas chromatograph. Iodine was emitted mainly as methyl iodide (CH3I), and CH3I emission was sometimes enhanced by the addition of glucose. Soils were then incubated with a radioactive iodine tracer (125I), and radioiodine emitted from soils was determined. The emission of iodine was enhanced in the presence of yeast extract but was inhibited by autoclaving of soils. The addition of streptomycin and tetracycline, antibiotics that inhibit bacterial growth, strongly inhibited iodine emission, while a fungal inhibitor cycloheximide caused little effect. Forty bacterial strains were randomly isolated from soils, and their capacities for volatilizing iodine were determined. Among these, 14 strains volatilized significant amounts of iodine when they were cultivated with iodide ion. Phylogenetic analysis based on 16S ribosomal DNA seque...
83 citations
TL;DR: Under conditions of alternative nutrition, there is a higher prevalence of iodine deficiency, which might be a consequence of exclusive or prevailing consumption of food of plant origin, no intake of fish and other sea products, as well as reduced iodine intake in the form of sea salt.
Abstract: Iodine content in food of plant origin is lower in comparison with that of animal origin due to a low iodine concentration in soil. Urinary iodine excretion was assessed in 15 vegans, 31 lacto- and la
77 citations
TL;DR: In this paper, the authors investigated urinary iodine concentration (UIC) in pregnant women and in female, non-pregnant controls in the canton of Berne, Switzerland, in 1992.
Abstract: We prospectively investigated urinary iodine concentration (UIC) in pregnant women and in female, non-pregnant controls in the canton of Berne, Switzerland, in 1992. Mean UIC of pregnant women [205 +/- 151 microg iodine/g creatinine (microg l/g Cr); no. = 153] steadily decreased from the first (236 +/- 180 microg l/g Cr; no. = 31) to the third trimester (183 +/- 111 microg l/g Cr, p < 0.0001; no. = 66) and differed significantly from that of the control group (91 +/- 37 microg l/g Cr, p < 0.0001; no. = 119). UIC increased 2.6-fold from levels indicating mild iodine deficiency in controls to the first trimester, demonstrating that high UIC during early gestation does not necessarily reflect a sufficient iodine supply to the overall population. Pregnancy is accompanied by important alterations in the regulation of thyroid function and iodine metabolism. Increased renal iodine clearance during pregnancy may explain increased UIC during early gestation, whereas increased thyroidal iodine clearance as well as the iodine shift from the maternal circulation to the growing fetal-placental unit, which both tend to lower the circulating serum levels of inorganic iodide, probably are the causes of the continuous decrease of UIC over the course of pregnancy. Mean UIC in our control group, as well as in one parallel and several consecutive investigations in the same region in the 1990s, was found to be below the actually recommended threshold, indicating a new tendency towards mild to moderate iodine deficiency. As salt is the main source of dietary iodine in Switzerland, its iodine concentration was therefore increased nationwide in 1998 for the fourth time, following increases in 1922, 1965 and 1980.
TL;DR: In this paper, a standardized, commercially available, sandwich fluoroimmunometric serum thyroglobulin assay was adapted for use on blood spots and validated in Swiss children.
TL;DR: Experiments suggested that the organic iodines were produced from the compounds released or contained in the media and cells were necessary for the considerable production of CH2I2 and CH2ClI, though CHI3 was produced by spent media with H2O2 or free iodine.
Abstract: Two strains of iodine-producing bacteria were isolated from marine samples. 16S rRNA gene sequences indicated the strains were most closely related to Roseovarius tolerans, and phylogenetic analysis indicated both belong to the same genus. 5 mM iodide inhibited the growth of strain 2S5-2 almost completely, and of strain S6V slightly. Both strains produced free iodine and organic iodine from iodide. CH2I2, CHI3 and CH2ClI were the main organic iodines produced by strain 2S5-2, and CHI3 and CH2I2 by strain S6V. Experiments using cells and spent media suggested that the organic iodines were produced from the compounds released or contained in the media and cells were necessary for the considerable production of CH2I2 and CH2ClI, though CHI3 was produced by spent media with H2O2 or free iodine.
TL;DR: Rapid introduction of iodized salt does not provoke significant thyroid autoimmunity in severely iodine-deficient children followed for 1 year and no child developed clinical or ultrasonographic evidence of thyroid autoimmune disease and/or iodine-induced hypothyroidism or hyperthyroidism.
Abstract: To determine if introduction of iodized salt induces thyroid autoimmunity in goitrous children, we conducted a prospective trial in iodine-deficient Moroccan schoolchildren (n = 323). Local salt was iodized at 25 μg iodine per gram of salt and distributed to households. Before introduction of iodized salt and at 10, 20, 40, and 52 weeks, we measured antithyroid peroxidase antibodies (TPO-Ab), antithyroglobulin antibodies (Tg-Ab), urinary iodine (UI), and thyroid hormones, and examined the thyroid using ultrasound. At baseline, median UI was 17 μg/L and the prevalence of goiter and hypothyroidism was 72% and 18%, respectively. Provision of iodized salt maintained median UI at 150-200 μg/L for the year (p < 0.0001). There was a significant increase in mean total thyroxine (T4) and a significant reduction in the prevalence of hypothyroidism (p < 0.001). There was a transient increase in the prevalence of detectable antibodies after introduction of iodized salt (p < 0.0001) with levels returning to baseline a...
TL;DR: Although the findings are not indicative of iodine deficiency in the overall population of the United States, the observed downward trend in iodine intake requires further close monitoring of iodine intake.
Abstract: Iodine is an essential requirement for thyroid hormone (TH) synthesis. The recommended daily iodine intake is variable, depending on the age of the subject; it is 40 µg/d during the neonatal period and 150 µg/d in the adult. The iodine requirement increases to approx 200 µg/d during pregnancy. Severe iodine deficiency, leading to various degrees of cretinism, is the major cause of mental and physical retardation in many developing countries, and its eradication is currently addressed by the International Council for Control of Iodine Deficiency Disorders (ICCIDD), United Nations International Children’s Education Fund (UNICEF), and World Health Organization (WHO). Mild to moderate iodine deficiency, ranging from 40–80 µg iodine daily, also is prevalent, including in many areas of continental Western Europe. In the United States, the average iodine intake in the 1988–1994 population was approx 150 µg/d, a decrease of more than 50% relative to 1971–1974 (1). A low iodine intake (<50 µg/d) was found in 11.7% of the population. Although the findings are not indicative of iodine deficiency in the overall population of the United States, the observed downward trend in iodine intake requires further close monitoring of iodine intake.
TL;DR: There is a high prevalence of iodine deficiency in these lactating postpartum subjects and Urine iodine as micrograms per gram of creatinine is a good predictor of breast milk iodine content.
Abstract: Iodine deficiency in the postpartum period has the potential to affect neonatal neuropsychointellectual development. We performed a cross-sectional study involving 50 postpartum women and their neonates, measuring maternal urine iodine, breast milk iodine, and neonatal thyroid stimulating hormone (TSH), and examining their interrelationships. Women were studied at a median (range) of 4 (3-9) days postpartum. Moderate to severe iodine deficiency (defined by urine iodine concentration < 50 μg/L) was found in 29 of the 50 subjects (58%). The median ± standard deviation (SD) urine iodine was 46.8 ± 28.5 μg/L and the mean urine iodine expressed in micrograms per gram of creatinine was 86.6 ± 45.6. The median (range) breast milk iodine was 84.0 μg/L (25.0-234.0). Breast milk iodine was significantly correlated with urine iodine in micrograms per gram of creatinine (r = 0.52, p < 0.001) but not with urine iodine measured in micrograms per liter (r = 0.19, p = 0.2). Six percent of neonates had whole-blood TSH val...
TL;DR: The results confirm that apoptosis is an important regulated and limited mechanism in goiter involution and may explain, why iodine supplementation even in high doses does not lead to thyroid atrophy but only normalisation of thyroid size.
Abstract: Iodine induced thyroid involution is caused by apoptosis rather than necrosis. This effect of iodide on apoptosis of thyroid epithelial cells may be not a direct one but mediated by iodinated derivatives i.e. of polyunsaturated fatty acids, especially of iodolactones, which have previously shown to inhibit thyroid cell proliferation. We studied the influence on apoptosis of iodide (2 microM and 20 microM) and iodolactone (0.05 microM and 0.5 microM), with and without TSH (1 mU/ml), using a well characterized ex vivo- culture system of intact porcine thyroid follicles in three-dimensional culture. Apoptosis and necrosis was evaluated by electron-microscopy. Stimulation with 2 and 20 microM iodide rapidly induced a rate of apoptosis (4 - 6 %) comparable to about 40-fold lower doses of delta-iodolactone (0.05 microM and 0.5 microM). Addition of TSH (1 mU/ml) caused a slight but not significant further increase of the incidence of apoptotic cells. The rate of necrotic thyroid epithelial cells (1 - 2 %) was similar in all experiments. As delta-iodolactone in very low concentrations--comparable to iodide in higher concentrations--not only inhibits growth but also induces apoptosis, it has to be supposed that the effect of iodide is mediated by this iodinated compound. However, further experiments are necessary to confirm this hypothesis. In addition it could be demonstrated, that apoptosis is a very rapid and limited process in intact follicles. This also may explain, why iodine supplementation even in high doses does not lead to thyroid atrophy but only normalisation of thyroid size. These results confirm that apoptosis is an important regulated and limited mechanism in goiter involution.
TL;DR: In this mini-review, issues regarding thiocyanate overload and thyroid disease will be summarized.
Abstract: Thiocyanate [SCN - ] is a complex anion which is a potent inhibitor of iodide transport. It is the detoxification product of cyanide and can easily be measured in body fluids. Consumption of naturally occurring goitrogens,certain environmental toxins and cigarette smoke can significantly increase SCN - concentrations to levels potentially capable of affecting the thyroid gland. Goiter endemics were reported to develop when the critical urinary iodine/ SCN - ratio decreases below 3 μg iodine per mg SCN - . Iodine supplementation completely reverses the goitrogenic influence of SCN - . SCN - is also generated from cigarette smoking as a detoxifying product of cyanide. During the past two decades many reports dealt with the possible effects of cigarette smoking on thyroid hormone synthesis, thyroid gland size and thyroid autoimmunity including infiltrative ophtalmopathy of Graves' disease. In this mini-review, issues regarding thiocyanate overload and thyroid disease will be summarized.
TL;DR: The reduction of iodate to iodide in laboratory cultures of the marine microalga Isochrysis galbana was found to be essentially independent on the presence or absence of nitrate reductase activity.
TL;DR: High NIS expression at both transcriptional and translational level and its ability to transport iodine in human breast tumors is reported and provides supportive evidence for use of radioiodine as an additional treatment modality of human breast carcinoma.
Abstract: Sodium iodide symporter (NIS) is a molecule involved in active accumulation of iodine in thyroid gland for the biosynthesis of thyroid hormone. Its expression has also been demonstrated in extra-thyroidal tissues including lactating mice mammary gland and also in human breast cancers. Iodide transport in thyroid cells through NIS is the basis for using radioiodine for diagnosis and treatment of differentiated thyroid carcinoma. The similar approach may prove beneficial for the diagnosis and treatment of breast cancer if iodine uptake, its retention and NIS expression can be shown unequivocally in malignant tumors. The aim of the present study was to investigate NIS expression, in vivo iodine transport ability and fate of iodine in human breast tumors. Women (age 33-58 years) with infiltrating duct carcinoma confirmed by FNAC and subsequent histopathology were the subject of this study. Expression of NIS RNA and protein was confirmed by RNAase protection assay, western blot and immunohistochemistry respectively in surgically excised breast tumor tissue. Iodine transport ability and its nature was assessed both in vivo and in vitro. We report high NIS expression at both transcriptional and translational level and its ability to transport iodine in human breast tumors. The in vivo iodine transport ability was confirmed by scintigraphy. Unlike thyroid, perchlorate and thiocyanate do not inhibit iodine transport in breast tumors. The presence of iodinated proteins suggests the longer retention time. The unequivocal demonstration of NIS expression, its functionality and retention of iodine by organification further provides supportive evidence for use of radioiodine as an additional treatment modality of human breast carcinoma.
TL;DR: A new method (“Fast B”) is presented that is rapid, inexpensive, reliable, and flexible for assessing urinary iodine concentration and is extended previous approaches with improved conditions.
Abstract: International groups recommend the following median urinary iodine concentration as the best single indicator of iodine nutrition in populations: severe deficiency, 0–0.15 μmol/L (0–19 μg/L); moderate deficiency, 0.16–0.38 μmol/L (20–49 μg/L); mild deficiency, 0.40–0.78 μmol/L (50–99 μg/L); optimal iodine nutrition, 0.79–1.56 μmol/L (100–199 μg/L); more than adequate iodine intake, 1.57–2.36 μmol/L (200–299 μg/L); and excessive iodine intake, ≥2.37 μmol/L (≥300 μg/L) (1). The range in which the median falls is more important than the precise number (2)(3).
Many methods for assessing urinary iodine exist (3)(4)(5)(6)(7)(8), most based on the Sandell–Kolthoff reaction (9), in which iodide catalyzes the reduction of ceric ammonium sulfate (yellow) to the colorless cerous form in the presence of arsenious acid. Although iodide is the chemical form for both the catalytic reaction and in urine, some preliminary treatment is needed to rid urine of impurities, most commonly by acid digestion (3)(5). We have extended previous approaches (5)(6)(10) with improved conditions and here present a new method (“Fast B”) that is rapid, inexpensive, reliable, and flexible.
The equipment required for the Fast B method includes a heating block, Pyrex test tubes (13 × 100 mm), two fixed-volume pipettes (0.5 mL and 1.0 mL), one adjustable pipette (0–200 μL), and a multipet (Eppendorf) for quick reagent volume additions of 0.125 and 0.1 mL. The basic chemicals used are potassium iodate, arsenic trioxide, ammonium persulfate, ammonium cerium(IV) sulfate dihydrate, sodium chloride, ferroine, and sulfuric acid.
The solutions used in the assay are as follows:
Patent•
30 Sep 2003
TL;DR: In this article, an article of manufacture (such as an identification document) capable of being laser engraved with a grayscale image, wherein the identification document (10) is a tnultilayer structure comprising at least one layer (52) which, comprises a host material and a laser enhancing additive.
Abstract: The invention provides for an article of manufacture (such as an identification document (10) capable of being laser engraved with a grayscale image, wherein the identification document (10) is a tnultilayer structure comprising at least one layer (52) which, comprises a host material and a laser enhancing additive. The host material comprises a material, such as a polymer, modified by a first process, whereby the host material modified by the first process has increased thermal conductivity as compared to the host material before the first process. The laser enhancing additive comprises a first quantity of at least one copper potassium iodide (CuKI3), Copper Iodide (CuI), potassium iodide (KI), sodium iodide (NaI), an aluminum iodide (A1I) and a second quaintly of at least one substance selected from the group consisting of zinc sulfide (ZnS), barium sulfide (BaS), alkyl sulfonate and thioester.
TL;DR: A compartmental model describing the distribution and retention of radioactive iodide in thyroid and other organs is presented, designed primarily for radiation dosimetry of iodine radionuclides used in nuclear medicine, but may also be useful for occupational radiation protection.
Abstract: A compartmental model describing the distribution and retention of radioactive iodide in thyroid and other organs is presented. The model is developed from published ICRP models. It is designed primarily for radiation dosimetry of iodine radionuclides used in nuclear medicine, but may also be useful for occupational radiation protection. In the proposed model, the distribution of iodide to the thyroid is assumed to be more rapid than in earlier models. Uptakes in stomach wall and salivary glands are considered, and the absorbed doses to these organs calculated. The partitioning of iodide between stomach wall and content is also discussed. Recirculation of organic iodine is also taken into account. Age-dependent half-times for iodide in the thyroid, as well as for organically-bound iodine are presented. The proposed model is applicable for dose estimations with different uptakes in the thyroid as well as for the situation when the thyroid is blocked, completely or incompletely.
Journal Article•
TL;DR: This is the first report demonstrating that a therapeutic dose of nonradioactive iodide has potent efficacy and high selectivity against lung cancer when used in combination with genetic modification of cancer cells to express the NIS/TPO genes.
Abstract: We assessed a nonradioactive approach to induce apoptosis in non-small cell lung cancer by a novel iodide uptake and retention mechanism. To enhance tumor apoptosis, we transduced non-small cell lung cancer cells with retroviral vectors containing the sodium iodide symporter (NIS) and thyroperoxidase (TPO) genes. Expression of NIS and TPO facilitated concentration of iodide in tumors. As a consequence of the marked increase in intracellular levels of iodide, apoptosis was seen in >95% of NIS/TPO-modified lung cancer cells. Intraperitoneal injection of potassium iodide resulted in significant tumor volume reduction in NIS/TPO-modified tumor xenografts without apparent adverse effects in SCID mice. Iodide induced an increase in the level of reactive oxygen species. Iodide-induced apoptosis is sensitive to N-acetylcysteine inhibition, suggesting an important role by reactive oxygen species in this apoptotic process. In addition, iodide-induced apoptosis is associated with overexpression of CDKN1A (p21/Waf1)and down-regulation of survivin at both mRNA and protein levels. This is the first report demonstrating that a therapeutic dose of nonradioactive iodide has potent efficacy and high selectivity against lung cancer when used in combination with genetic modification of cancer cells to express the NIS/TPO genes.
TL;DR: X-ray crystal structural analysis of two Benziodazole-based phenyliodonium derivatives provides insight into facile interchange between benziodazoles and iminium benziodoxoles under acidic or basic conditions.
TL;DR: The molecular-iodine and iodide-ion contents of corn amylose and corn starch complexes were determined by a differential method requiring titrations with both KIO3 and Na2S2O3 as mentioned in this paper.
TL;DR: In this paper, the thyroid gland was protected from 123/131I uptake by potassium iodide during radiolabeled metaiodobenzylguanidine (MIBG) administration in children with neuroblastoma.
Abstract: BACKGROUND
During radiolabeled metaiodobenzylguanidine (MIBG) administration in children with neuroblastoma, the thyroid is protected from 123/131I uptake by potassium iodide. Despite this protection, up to 64% of patients develop thyroid dysfunction. The authors introduce a new method of radiation protection for the thyroid gland.
METHODS
In a prospective cohort study, 34 children with neuroblastoma who received MIBG were given thyroxine, methimazole, and potassium iodide for protection of the thyroid gland. Protection started 1 day before the start of diagnostic 123I-MIBG and was continued until 4 weeks after the last therapeutic 131I-MIBG dose. Follow-up measurements were performed every 3 months after the protection was stopped. Visualization of the thyroid on MIBG images was reviewed by three nuclear medicine physicians. Results were compared with a historic control group of children who had received potassium iodide for thyroid protection during MIBG administration.
RESULTS
After a mean follow-up of 19 months, there were 23 evaluable patients. Thyroid function was normal in 86% of survivors compared with 44% of children in the historic control group (P = 0.011; Pearson chi-square test). Scintigraphic visualization of the thyroid diminished substantially after the new protection (21.5% vs. 5.3%, respectively; P = 0.000).
CONCLUSIONS
The results of the current study indicate that compared with potassium iodide alone, combined thyroxine, methimazole, and potassium iodide protect the thyroid more effectively against radiation damage from 123/131I during diagnostic and therapeutic MIBG administration in children with neuroblastoma. Cancer 2003;98:389–96. © 2003 American Cancer Society.
DOI 10.1002/cncr.11523
TL;DR: Findings suggest that selected combinations of NHR ligands should be examined in a limited trial to determine if their administration to patients allows the use of radioactive iodine for diagnosis and possibly treatment of metastatic breast cancer.
Abstract: Iodide uptake by normal and cancerous thyroid cells is an active process mediated by the sodium/iodide symporter (NIS). Using quantitative real-time RT-PCR, we found that all 22 fresh human breast cancer samples had very low NIS expression similar to levels in untreated MCF-7 breast cancer cells. 9-cis retinoic acid (9-cis RA), a ligand for both retinoic acid receptor (RAR)/retinoic X receptor (RXR) heterodimers as well as RXR/RXR homodimers, markedly induced NIS mRNA expression in MCF-7 breast cancer cells in a dose- and time-dependent fashion, with maximal levels occurring at 12 h. All-trans retinoic acid, ATRA, a RAR specific ligand had a similar potency. Among eight breast cancer cell lines, three out of four estrogen receptor (ER)-positive and zero of four ER-negative cell lines responded to 9-cis RA by increasing their expression of NIS. Combining a RAR with a RXR selective ligand enhanced both NIS mRNA expression and iodide uptake in MCF-7 cells. Similarly, a ligand for proliferator-activated receptor gamma (PPARgamma) when combined with 9-cis RA synergistically increased both NIS mRNA levels and iodide uptake in these MCF-7 cells. The iodide uptake was blocked by KClO4. In conclusions, these findings suggest that selected combinations of NHR ligands should be examined in a limited trial to determine if their administration to patients allows the use of radioactive iodine for diagnosis and possibly treatment of metastatic breast cancer.
TL;DR: Mild-to-moderate iodine deficiency exists in Lesotho and Iodine deficiency was more severe in the mountains than the lowlands and is still a concern for public health.
Abstract: Objective To estimate the prevalence of goitre, urinary iodine status, coverage of supplementation of iodized oil capsules, and current use of iodized salt in children in Lesotho. Methods Cross-sectional study of children from 50 primary schools in Lesotho. Thyroid glands of children aged 8–12 years were measured by palpation and graded according to the WHO, UNICEF, and the International Council for the Control of Iodine Deficiency’s (ICCIDD) joint criteria. The use of iodized oil capsules was determined by a structured questionnaire and verified with the children’s health booklets. Iodine content of household salt samples was analysed. Casual urine samples were analysed for urinary iodine. Findings Median urinary iodine concentrations of 26.3 mg/l (range 22.3–47.9 mg/l) indicated moderate iodine deficiency. More children in the mountains than in the lowlands were severely iodine deficient (17.7% vs 1.9%). Adjusted prevalence of goitre (4.9%) increased with age, was higher in girls than boys, and ranged from 2.2% to 8.8% in the different districts; this indicated no public health problem. Overall, 94.4% of salt samples were iodized, and coverage of supplementation with iodized oil capsules was 55.1%. Conclusion Mild-to-moderate iodine deficiency exists in Lesotho. Iodine deficiency was more severe in the mountains than the lowlands and is still a concern for public health. Use of iodized salt coupled with iodized oil supplementation effectively controls iodine deficiency disorders. Effective monitoring programmes would ensure the use of adequately iodized salt throughout Lesotho and serve to evaluate progress towards optimal iodine nutrition. Iodized oil capsule supplementation should continue in the mountains.
TL;DR: In this article, the reaction mechanism is modelled by spreadsheet, with parallel rate determining steps involving couplets such as HOI with I2OH−, all in pre-equilibrium with each other.
Abstract: Phosphate and borate buffers used commonly in the study of the disproportionation of iodine(0) into iodate (I(+5)) and iodide (I(−1)) catalyse the reaction. This offers significant advantages when the reaction is used to contain radio-iodine in a rupturing fission reactor, e.g., Three Mile Island. Here, such buffer catalysis has been investigated in solutions 0.20 mol l−1 in phosphate, borate, acetate or carbonate, with between 0–0.10 mol l−1 iodide. The reaction mechanism is modelled by spreadsheet, with parallel rate determining steps involving couplets such as HOI with I2OH−, all in pre-equilibrium with each other. At a given iodide concentration the kinetics are characterised by a peak in the graph of apparent rate constant versus pH. The peaks for hydroxide and each of the buffers except carbonate, coincided; carbonate displayed slightly anomalous behaviour at higher concentrations of iodide (0.10 mol l−1). The presence of a pKa in the pH domain occupied by the peak was not found to have any significant bearing on the result. The apparent rate constant for disproportionation increased linearly with phosphate concentration when the pH was that of the top of the peak. However, with the pH set on the shoulders of the peak catalysis increased initially, but then became saturated. It is not possible to ascribe, as in simpler systems, a single value to the catalytic activity of each buffer, which would apply across the entire reaction domain. In phosphate, a combination of parallel rate determining reactions involving I2OH−/IO−, I2OH−/HOI and HOI/IO− couplets was found to offer the best solution to the simultaneous fitting of the model to several sets of data. The reactivity of these couplets is investigated by means of molecular orbital theory.