Iodine

NHANES III measured serum TSH, total serum T 4 , antithyroperoxidase (TPOAb), and antithyroglobulin (TgAb) antibodies from a sample of 17,353 people aged >12 yr representing the geographic and ethnic distribution of the U.S. population. These data provide a reference for other studies of these analytes in the U.S.

The Guideline for Hand Hygiene in Health-Care Settings provides health-care workers (HCWs) with a review of data regarding handwashing and hand antisepsis in health-care settings. In addition, it provides specific recommendations to promote improved hand-hygiene practices and reduce transmission of pathogenic microorganisms to patients and personnel in health-care settings. This report reviews studies published since the 1985 CDC guideline (Garner JS, Favero MS. CDC guideline for handwashing and hospital environmental control, 1985. Infect Control 19867:231-43) and the 1995 APIC guideline (Larson EL, APIC Guidelines Committee. APIC guideline for handwashing and hand antisepsis in health care settings. Am J Infect Control 1995;23:251-69) were issued and provides an in-depth review of hand-hygiene practices of HCWs, levels of adherence of personnel to recommended handwashing practices, and factors adversely affecting adherence. New studies of the in vivo efficacy of alcohol-based hand rubs and the low incidence of dermatitis associated with their use are reviewed. Recent studies demonstrating the value of multidisciplinary hand-hygiene promotion programs and the potential role of alcohol-based hand rubs in improving hand-hygiene practices are summarized. Recommendations concerning related issues (e.g., the use of surgical hand antiseptics, hand lotions or creams, and wearing of artificial fingernails) are also included.

The present comments are restricted to the role of maternal thyroid hormone on early brain development, and are based mostly on information presently available for the human fetal brain. It emphasizes that maternal hypothyroxinemia -defined as thyroxine (T4) concentrations that are low for the stage of pregnancy -is potentially damaging for neurodevelopment of the fetus throughout pregnancy, but especially so before midgestation, as the mother is then the only source of T4 for the developing brain. Despite a highly efficient uterine -placental 'barrier' to their transfer, very small amounts of T4 and triiodothyronine (T3) of maternal origin are present in the fetal compartment by 4 weeks after conception, with T4 increasing steadily thereafter. A major proportion of T4 in fetal fluids is not protein-bound: the 'free' T4 (FT4) available to fetal tissues is determined by the maternal serum T4, and reaches concentrations known to be of biological significance in adults. Despite very low T3 and 'free' T3 (FT3) in fetal fluids, the T3 generated locally from T4 in the cerebral cortex reaches adult concentrations by midgestation, and is partly bound to its nuclear receptor. Experimental results in the rat strongly support the conclusion that thyroid hormone is already required for normal corticogenesis very early in pregnancy. The first trimester surge of maternal FT4 is proposed as a biologically relevant event controlled by the conceptus to ensure its developing cerebral cortex is provided with the necessary amounts of substrate for the local generation of adequate amounts of T3 for binding to its nuclear receptor. Women unable to increase their production of T4 early in pregnancy would constitute a population at risk for neurological disabilities in their children. As mild-moderate iodine deficiency is still the most widespread cause of maternal hypothyroxinemia in Western societies, the birth of many children with learning disabilities may already be preventable by advising women to take iodine supplements as soon as pregnancy starts, or earlier if possible.

Purpose The Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) has updated its 1999 guidelines on contrast medium-induced nephropathy (CIN). Areas covered Topics reviewed include the definition of CIN, the choice of contrast medium, the prophylactic measures used to reduce the incidence of CIN, and the management of patients receiving metformin. Key Points • Definition, risk factors and prevention of contrast medium induced nephropathy are reviewed. • CIN risk is lower with intravenous than intra-arterial iodinated contrast medium.

Organic-inorganic perovskites such as CH3NH3PbI3 are promising materials for a variety of optoelectronic applications, with certified power conversion efficiencies in solar cells already exceeding 21%. Nevertheless, state-of-the-art films still contain performance-limiting non-radiative recombination sites and exhibit a range of complex dynamic phenomena under illumination that remain poorly understood. Here we use a unique combination of confocal photoluminescence (PL) microscopy and chemical imaging to correlate the local changes in photophysics with composition in CH3NH3PbI3 films under illumination. We demonstrate that the photo-induced 'brightening' of the perovskite PL can be attributed to an order-of-magnitude reduction in trap state density. By imaging the same regions with time-of-flight secondary-ion-mass spectrometry, we correlate this photobrightening with a net migration of iodine. Our work provides visual evidence for photo-induced halide migration in triiodide...

Iodine is an essential component of thyroid hormones; either low or high intake may lead to thyroid disease. We observed an increase in the prevalence of overt hypothyroidism, subclinical hypothyroidism, and autoimmune thyroiditis with increasing iodine intake in China in cohorts from three regions with different levels of iodine intake: mildly deficient (median urinary iodine excretion, 84 μg per liter), more than adequate (median, 243 μg per liter), and excessive (median, 651 μg per liter). Participants enrolled in a baseline study in 1999, and during the five-year follow-up through 2004, we examined the effect of regional differences in iodine intake on the incidence of thyroid disease.

Purpose: Bloodstream infections related to use of catheters, particularly central-line catheters, are an important cause of patient morbidity, mortality, and increased health care costs. This study evaluated the efficacy of skin disinfection with chlorhexidine gluconate compared with povidone-iodine solution in preventing catheter-related bloodstream infection. Data Sources: Multiple computerized databases (1966 to 2001), reference lists of identified articles, and queries of principal investigators and antiseptic manufacturers. Study Selection: Randomized, controlled trials comparing chlorhexidine gluconate with povidone-iodine solutions for cathetersite care. Data Extraction: Using a standardized form, two reviewers abstracted data on study design, patient population, intervention, and incidence of catheter-related bloodstream infection from all included studies. Data Synthesis: Eight studies involving a total of 4143 catheters met the inclusion criteria. All studies were conducted in a hospital setting, and various catheter types were used. The summary risk ratio for catheter-related bloodstream infection was 0.49 (95% CI, 0.28 to 0.88) in patients whose catheter sites were disinfected with chlorhexidine gluconate instead of povidoneiodine. Among patients with a central vascular catheter, chlorhexidine gluconate reduced the risk for catheter-related bloodstream infection by 49% (risk ratio, 0.51 [CI, 0.27 to 0.97]).

The prevalence of thyroid nodules in a healthy population is high: in the German Papillon study, nationwide ultrasound screening of more than 90 000 people using 7.5 MHz scanners revealed the presence of thyroid nodules in 33% of the normal population. A study employing more sensitive 13 MHz scanners has not been conducted so far. Six hundred and thirty-five consecutive patients (33% female, 67% male, mean 56.7 years) presenting for a preventive health check up underwent ultrasound screening of the thyroid gland (Siemens Acuson Antares, 13 MHz-linear scanner, B-mode and Power mode) and measurement of the basal TSH (thyroid stimulating hormone) value. Size and degree of vascularization of the thyroid gland and of nodules were determined and analysed retrospectively. In 432 of 635 patients, thyroid nodules could be detected with an increasing incidence with age, in 338 without goiter. Mean thyroid size was 12.3 mL for women and 20.5 mL for men correlating strongly with body weight. Fifty-three percentage of the nodules were smaller than 5 mm. Incidence of thyroid dysfunction was only 4%. No cancerous lesions could be found. Using the 13 MHz technology, we found a substantially higher prevalence of thyroid nodules (68%) than the Papillon study (33%). Even if our population is older than in Papillon, the difference remains in comparable age groups. This is due to the higher sensitivity of 13 MHz scanning. Our study underlines the clinical significance of iodine deficiency and should renew the discussion on routine iodine supplementation.

Background: After the Chernobyl nuclear power plant accident in April 1986, a large increase in the incidence of childhood thyroid cancer was reported in contaminated areas. Most of the radiation exposure to the thyroid was from iodine isotopes, especially 131 I. We carried out a populationbased case -control study of thyroid cancer in Belarus and the Russian Federation to evaluate the risk of thyroid cancer after exposure to radioactive iodine in childhood and to investigate environmental and host factors that may modify this risk. Methods: We studied 276 case patients with thyroid cancer through 1998 and 1300 matched control subjects, all aged younger than 15 years at the time of the accident. Individual doses were estimated for each subject based on their whereabouts and dietary habits at the time of the accident and in following days, weeks, and years; their likely stable iodine status at the time of the accident was also evaluated. Data were analyzed by conditional logistic regression using several different models. All statistical tests were two-sided. Results: A strong dose -response relationship was observed between radiation dose to the thyroid received in childhood and thyroid cancer risk ( P <.001). For a dose of 1 Gy, the estimated odds ratio of thyroid cancer varied from 5.5 (95% confi dence interval [CI] = 3.1 to 9.5) to 8.4 (95% CI = 4.1 to 17.3), depending on the risk model. A linear dose -response relationship was observed up to 1.5 -2 Gy. The risk of radiation-related thyroid cancer was three times higher in iodine-defi cient areas (relative risk [RR]= 3.2, 95% CI = 1.9 to 5.5) than elsewhere. Administration of potassium iodide as a dietary supplement reduced this risk of radiation-related thyroid cancer by a factor of 3 (RR = 0.34, 95% CI = 0.1 to 0.9, for consumption of potassium iodide versus no consumption). Conclusion: Exposure to 131 I in childhood is associated with an increased risk of thyroid cancer. Both iodine defi ciency and iodine supplementation appear to modify this risk. These results have important public health implications: stable iodine supplementation in iodine-defi cient populations may substantially reduce the risk of thyroid cancer related to radioactive iodines in case of exposure to radioactive iodines in childhood that may occur after radiation accidents or during medical diagnostic and therapeutic procedures.

Polybrominated diphenyl ethers (PBDEs), used as flame retardants, are ubiquitous environmental contaminants. PBDEs act as endocrine disruptors via alterations in thyroid hormone homeostasis. We examined thyroid hormone concentrations and hepatic enzyme activity in weanling rats exposed to three commercial PBDE mixtures: DE-71, DE-79, and DE-83R. Female Long-Evans rats, 28 days old, were orally administered various doses of DE-71,

Hypervalent iodine reagents constitute a powerful tool in modern synthetic organic chemistry, promoting several important reactions. One such reaction is the ring contraction of cycloalkenes and cycloalkanones promoted by iodine(III) compounds, such as iodobenzene diacetate, iodosylbenzene, iodotoluene difluoride, and [hydroxy(tosyloxy)iodo]benzene (Koser´s reagent). This review covers all the literature related to the ring contraction of cyclic ketones and olefins promoted by iodine(III) species.

Abstract—The cardiovascular signs and symptoms,of thyroid disease are some of the most profound and clinically relevant findings that accompany,both hyperthyroidism,and hypothyroidism. On the basis of the understanding of the cellular mechanisms of thyroid hormone action on the heart and cardiovascular system, it is possible to explain the changes in cardiac output, cardiac contractility, blood pressure, vascular resistance, and rhythm disturbances

A general method for a highly regioselective, copper-catalyzed cross-coupling of two aromatic compounds by using iodine oxidant has been developed. The reactions involve an initial iodination of one arene followed by arylation of the most acidic C-H bond of the other coupling component. Cross-coupling of electron-rich arenes, electron-poor arenes, five-and six-membered heterocycles is possible in many combinations. Typically, 1/1.5 to 1/3 ratio of coupling components is used in contrast to existing methodology that often employs a large excess of one of the arenes. Common functionalities such as ester, ketone, aldehyde, ether, nitrile, nitro, and amine are well-tolerated.

Electronic spectra Positron annihilation lifetime spectroscopy a b s t r a c t Molecular charge-transfer complexes of the tetramethylethylenediamine (TMEDA) with picric acid (Pi-OH), benzene-1,4-diol (QL), tin(IV) tetrachloride (SnCl 4 ), iodine, bromine, and zinc chloride (ZnCl 2 ) have been synthesized and investigated by elemental and thermal analysis, electronic, infrared, Raman and proton-NMR, energy-dispersive X-ray spectroscopy, X-ray powder diffraction and positron annihilation lifetime spectroscopy, and scanning electron microscopy. In this work, three types of acceptors p-acceptors (Pi-OH and QL), r-acceptors (iodine and bromine), and vacant orbital acceptors (SnCl 4 and ZnCl 2 ) were covered. The results of elemental analysis indicated that the CT complexes were formed with ratios 1:1 and 1:2 for QL, SnCl 4 , and ZnCl 2 acceptors and iodine, Pi-OH, and Br 2 acceptors, respectively. The type of chelating between the TMEDA donor and the mentioned acceptors depends upon the behavior of both items. The positron annihilation lifetime parameters were found to be dependent on the structure, electronic configuration, and the power of acceptors. The correlation between these parameters and the molecular weight and biological activities of studied complexes was also observed. Regarding the electrical properties, the AC conductivity and the dielectric coefficients were measured as a function of frequency at room temperature. The TMEDA charge-transfer complexes were screened against antibacterial (Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa) and antifungal (Aspergillus flavus and Candida albicans) activities.

Increased micronutrient density in grain destined for human consumption may alleviate micronutrient de®ciencies (Fe, Zn, Cu, and I) in human populations around the world. The review of literature indicates that fertilization with inorganic and organic forms of micronutrients has a potential to increase their concentrations in grain. The most effective fertilization could be via soil (for Zn and, to some extent, Cu), foliarly (for Fe) and by adding fertilizers to the irrigation water (for iodine). Care should be exercised not to overfertilize crops with micronutrients because of consequent toxicity and losses in quality and quantity of grain yield. Effectiveness of various agricultural measures in increasing micronutrient density depends on soil type, crop, cultivar, rotation, and environmental and other factors, thus necessitating development of a speci®c set of measures for individual regions. Agricultural measures would need to be supplemented with appropriate changes in the milling technology to ascertain that increased micronutrient concentrations in some grain parts are passed into the food chain. # 0378-4290/99/$ ± see front matter # 1999 Elsevier Science B.V. All rights reserved. P I I : S 0 3 7 8 -4 2 9 0 ( 9 8 ) 0 0 1 3 1 -2

This paper examines the relationship between early cognitive development, socio-economic status (SES), child health, and parenting quality in a developing country. We use a sample of over 3,000 predominantly poor pre-school age children from Ecuador, and analyze determinants of their scores on the Spanish version of the Peabody Picture Vocabulary Test (TVIP), a widely used test of language ability. We show that median age-normed test scores on the TVIP are much lower for older than younger children, and there is greater dispersion in scores among older children. We find that household socio-economic characteristics, in particular wealth and parental education, are "protective"-children from wealthier households and with more educated parents have higher scores. The associations of test scores with wealth and maternal education are larger for older children, suggesting that these factors have cumulative effects on cognitive ability. Last, we show that child health and measures of parenting quality are associated with performance on the TVIP. Children with lower hemoglobin levels perform worse on tests. Measures of parenting quality, in particular the degree to which parents are "responsive" and "harsh" toward children, and whether children are read to, account for a portion, although not the majority, of the association between SES and cognitive development.

Iodine deficiency is a global public health problem, and estimates of the extent of the problem were last produced in 2003. To provide updated global estimates of the magnitude of iodine deficiency in 2007, to assess progress since 2003, and to provide information on gaps in the data available. Recently published, nationally representative data on urinary iodine (UI) in school-age children collected between 1997 and 2006 were used to update country estimates of iodine nutrition. These estimates, alongside the 2003 estimates for the remaining countries without new data, were used to generate updated global and regional estimates of iodine nutrition. The median UI was used to classify countries according to the public health significance of their iodine nutrition status. Progress was measured by comparing current prevalence figures with those from 2003. The data available for pregnant women by year of survey were also assessed. New UI data in school-age children were available for 41 ...

To investigate the potential of spectral computed tomography (CT) (popularly referred to as multicolor CT), used in combination with a gold high-density lipoprotein nanoparticle contrast agent (Au-HDL), for characterization of macrophage burden, calcifi cation, and stenosis of atherosclerotic plaques.

A novel class of visible light-activated photocatalysts was prepared by codoping TiO 2 with cerium and iodine (Ce-I-TiO 2 ). The particles were characterized using the Brunauer-Emmett-Teller method, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UV-Visible light absorption. Particles of Ce-I-TiO 2 had greater photoabsorption in the 400-800 nm wavelength range than iodine-doped TiO 2 (I-TiO 2 ). The effects on the photocatalytic degradation of oxalic acid under visible light or UV-Visible light irradiation were investigated. The photocatalytic activity of Ce-I-TiO 2 calcined at 673 K was significantly higher than that of Ce-I-TiO 2 calcined at 773 K and I-TiO 2 calcined at 673 K in aqueous oxalic acid solution under visible light or UV-Visible light irradiation. Under visible light irradiation, oxalic acid was first adsorbed on the surface of the catalysts rather than reacted with free radicals in the bulk solution, and then oxidized by Å OH ads to CO 2 , which was verified by studying the effects of nitrogen purging and scavengers, as well as by gas chromatography/mass spectrometry.

Two natural waters were fortified with various levels of bromide or iodide ions (0-30 µM) and chlorinated in the laboratory to study the impact of bromide and iodide ions on the formation and speciation of disinfection byproducts. Trihalomethanes (THMs), haloacetic acids (HAAs), total organic halogen (TOX), and its halogen-specific fractions total organic chlorine (TOCl), bromine (TOBr), and iodine (TOI), were measured in this work. The molar yields of THMs and HAAs increased as the initial bromide concentration increased. No significant change in TOX concentration was found for varying bromide concentrations. However, TOX concentrations decreased substantially with increasing initial iodide concentrations. At higher levels of bromide, there was a decreasing level of unknown TOX and unknown TOCl but an increasing level of unknown TOBr. The extent of iodine substitution was much lower than that of bromine substitution when comparing identical initial concentrations because a substantial amount of iodide was oxidized to iodate by chlorine. The tendency toward iodate formation resulted in the unusual situation where higher chlorine doses actually caused reduced levels of iodinated organic byproducts. Quantitative assessment of the results of this study showed a good agreement with kinetic data in the literature.

In this paper, we demonstrate the effect of halide ions on the formation of biogenically prepared gold nanotriangles using the leaf extract of lemongrass (Cymbopogon flexuosus) plant. We have also studied the effect of halide ions on the morphology of biogenic nanotriangles. It has been shown that iodide ions have a greater propensity to transform flat gold nanotriangles into circular disklike structures as compared to other halide ions. The study also suggests that the presence of Clions during the synthesis promotes the growth of nanotriangles, whereas the presence of Iions distorts the nanotriangle morphology and induces the formation of aggregated spherical nanoparticles. The change in the morphology of gold nanotriangles has been explained in terms of the ability of the halide ions to stabilize or inhibit the formation of (111) faces to form [111] oriented gold nanotriangles. Last, we have also shown that the temperature is an important parameter for controlling the aspect ratio and the relative amounts of gold nanotriangles and spherical particles. The results show that, by varying the temperature of reaction condition, the shape, size, and optical properties of anisotropic nanoparticles can be fine-tuned.

In 1948, Wolff and Chaikoff reported that organic binding of iodide in the thyroid was decreased when plasma iodide levels were elevated (acute Wolff-Chaikoff effect), and that adaptation or escape from the acute effect occurred in approximately 2 days, in the presence of continued high plasma iodide concentrations. We later demonstrated that the escape is attributable to a decrease in iodide transport into the thyroid, lowering the intrathyroidal iodine content below a critical inhibitory threshold and allowing organification of iodide to resume. We have now measured the rat thyroid sodium/iodide symporter (NIS) messenger RNA (mRNA) and protein levels, in response to both chronic and acute iodide excess, in an attempt to determine the mechanism responsible for the decreased iodide transport. Rats were given 0.05% NaI in their drinking water for 1 and 6 days in the chronic experiments, and a single 2000-g dose of NaI ip in the acute experiments. Serum was collected for iodine and hormone measurements, and thyroids were frozen for subsequent measurement of NIS, TSH receptor, thyroid peroxidase (TPO), thyroglobulin, and cyclophilin mRNAs (by Northern blotting) as well as NIS protein (by Western

Background: Maternal hypothyroxinemia, due to gestational iodine deficiency, causes neurological dysfunctions in the progeny. Our aim was to determine the effects of delayed iodine supplementation (200 mg KI per day) to mildly hypothyroxinemic pregnant women at the beginning of gestation (i.e., having circulating free thyroxine [FT 4 ] within the 0th-10th percentile interval and normal thyrotropin [TSH]) on the neurobehavioral development of their children. Methods: Using the Brunet-Lézine scale, we evaluated the neurocognitive performance at 18 months of age in three groups of children. Group 1 included children of women with FT 4 above the 20th percentile at 4-6 gestational weeks and at full-term. Group 2 included children of mildly hypothyroxinemic women diagnosed during the first 12-14 gestational weeks and with FT 4 above the 20th percentile at full-term. Group 3 included children born to mildly hypothyroxinemic women at full-term, without iodine supplementation during gestation. Women of all groups were iodine supplemented from the day of enrollment until the end of lactation. Results: Before iodine supplementation, 33.0% of the women (114 out of 345) were hypothyroxinemic, with FT 4 below normal in 28 of them (8.1%). None were found to be hypothyroxinemic at full-term after supplementation. The mean (AESD) developmental quotient of children was 101.8 AE 9.7 in group 1 (n ¼ 13) vs. 87.5 AE 8.9 in group 3 (n ¼ 19; p < 0.001) and 92.2 AE 5.4 in group 2 (n ¼ 12; p < 0.05). The difference between groups 2 and 3 was not statistically significant. Delayed neurobehavioral performance was observed in 36.8% and 25.0% of children in groups 3 and 2, respectively, compared with no children in group 1. Differences ( p < 0.001) were found on gross and fine motor coordination and socialization quotients. No statistically significant differences were found on language quotients. Conclusions: A delay of 6-10 weeks in iodine supplementation of hypothyroxinemic mothers at the beginning of gestation increases the risk of neurodevelopmental delay in the progeny. Public health programs should address the growing problem of iodine deficiency among women of gestational age in developing and industrialized nations.

The purpose of this study was to evaluate whether 123-iodine metaiodobenzylguanidine (123-I MIBG) imaging predicts ventricular arrhythmias causing appropriate implantable cardioverter-defibrillator (ICD) therapy (primary end point) and the composite of appropriate ICD therapy or cardiac death (secondary end point).

The unified global efforts to mitigate the high burden of vitamin and mineral deficiency, known as hidden hunger, in populations around the world are crucial to the achievement of most of the Millennium Development Goals (MDGs). We developed indices and maps of global hidden hunger to help prioritize program assistance, and to serve as an evidence-based global advocacy tool. Two types of hidden hunger indices and maps were created based on i) national prevalence data on stunting, anemia due to iron deficiency, and low serum retinol levels among preschool-aged children in 149 countries; and ii) estimates of Disability Adjusted Life Years (DALYs) attributed to micronutrient deficiencies in 136 countries. A number of countries in sub-Saharan Africa, as well as India and Afghanistan, had an alarmingly high level of hidden hunger, with stunting, iron deficiency anemia, and vitamin A deficiency all being highly prevalent. The total DALY rates per 100,000 population, attributed to micronutrient deficiencies, were generally the highest in sub-Saharan African countries. In 36 countries, home to 90% of the world's stunted children, deficiencies of micronutrients were responsible for 1.5-12% of the total DALYs. The pattern and magnitude of iodine deficiency did not conform to that of other micronutrients. The greatest proportions of children with iodine deficiency were in the Eastern Mediterranean (46.6%), European (44.2%), and African (40.4%) regions. The current indices and maps provide crucial data to optimize the prioritization of program assistance addressing global multiple micronutrient deficiencies. Moreover, the indices and maps serve as a useful advocacy tool in the call for increased commitments to scale up effective nutrition interventions.

In the past several years, halogen bonds have been shown to be relevant in crystal engineering and biomedical applications. One of the reasons for the utility of these types of noncovalent interactions in the development of, for example, pharmaceutical ligands is that their strengths and geometric properties are very tunable. That is, substitution of atoms or chemical groups in the vicinity of a halogen can have a very strong effect on the strength of the halogen bond. In this study we investigate halogen-bonding interactions involving aromatically-bound halogens (Cl, Br, and I) and a carbonyl oxygen. The properties of these halogen bonds are modulated by substitution of aromatic hydrogens with fluorines, which are very electronegative. It is found that these types of substitutions have dramatic effects on the strengths of the halogen bonds, leading to interactions that can be up to 100% stronger. Very good correlations are obtained between the interaction energies and the magnitudes of the positive electrostatic potentials (σ-holes) on the halogens. Interestingly, it is seen that the substitution of fluorines in systems containing smaller halogens results in electrostatic potentials resembling those of systems with larger halogens, with correspondingly stronger interaction energies. It is also shown that aromatic fluorine substitutions affect the optimal geometries of the halogen-bonded complexes, often as the result of secondary interactions.

Objective: The relations between oral contraceptives (OC), hormone replacement therapy (HRT) for menopause, and other female hormone use and thyroid cancer risk was analyzed using the original data from 13 studies from North America, Asia and Europe. Methods: Based on 2,132 cases and 3,301 controls, odds ratios (OR) and the corresponding 95% confidence intervals (CI) were obtained by conditional regression models, conditioning on study and age at diagnosis, and adjusting for age, radiation exposure and parity. Results: Overall, 808 (38%) cases versus 1,290 (39%) controls had ever used OCs, corresponding to an OR of 1.2 (95% CI 1.0 to 1.4). There was no relation with duration of use, age at first use, or use before first birth. The OR was significantly increased for current OC users (OR=1.5, 95% 1.0 to 2.1), but declined with increasing time since stopping (OR=1.1 for >10 years since stopping). The association was stronger for papillary cancers (OR=1.6 for current users) than for other histologic types. No significant heterogeneity was observed across studies or geographic areas. Eight studies had data on HRT, for a total of 1,305 cases and 2,300 controls: 110 (8%) cases and 205 (9%) controls reported ever using HRT (OR=0.8; 95% CI 0.6 to 1.1). The ORs were 1.6 (95% to 0.9 to 2.9) for use of fertility drugs, and 1.5 (95% CI 1.1 to 2.1) for lactation suppression treatment. Conclusions: The studies considered in these analyses include most of the epidemiological data on the role of exogenous hormone use in the etiology of thyroid cancer, and they provide reassuring evidence on the absence of an association of practical relevance. The moderate excess risk in current OC users, if not due to increased surveillance for thyroid masses among OC users, is similar to that described for breast cancer, and would imply a role of female hormones on thyroid cancer promotion. There was no indication of increased thyroid cancer risk 10 or more years after discontinuing OC use.

The electrophysiological properties of the Na+fl-symporter (NIS) were examined in a cloned rat thyroid cell line (FRTL-5) using the whole-cell patch-clamp technique. When the holding potential was between-40 mV and-80 mV, 1 mM NaI and NaSCN induced an immediate inward current which was greater with SCN-than with I-. The reversal potential for Iand SCN-induced membrane currents was +50 inV. This is close to the value of +55 mV calculated by the Nernst equation for Na +. These results are consistent with I-and SCN-translocation via the NIS that is energized by the electrochemical gradient of Na + and coupled to the transport of two or more Na ÷. There was no change in the membrane current recording with C10 4 indicating that C10 4 was either not transported into the cell, or the translocation was electroneutral. C10 4 addition, however, did reverse the inward currents induced by I-or SCN-. These effects of I-, SCN-and C10 4 on membrane currents reflect endogenous NIS activity since the responses duplicated those seen in CHO ceils transfected with NIS. There were additional currents elicited by SCN-in FRTL-5 cells under certain conditions. For example at holding potentials of 0 and +30 mV, 1 mM SCN-produced an increasingly greater outward current. This outward current was transient. In addition, when SCN-was washed off the cells a transient inward current was detected. Unlike SCN-, 1-10 mM I-had no observable effect on the membrane current at holding potentials of 0 and +30 mV. The results indicate FRTL-5 cells may have a specific SCN-translocation system in addition to the SCN-translocation by the I-porter. Differences demonstrated in current response may explain some of the complicated influx and efflux properties of I-, SCN-and C10 4 in thyroid cells.

An inadequate supply of iodine during gestation results in damage to the foetal brain that is irreversible by mid-gestation unless timely interventions can correct the accompanying maternal hypothyroxinemia. Even mild to moderate maternal hypothyroxinemia may result in suboptimal neurodevelopment. This review mainly focuses on iodine and thyroid hormone economy up to mid-gestation, a period during which the mother is the only source for the developing brain of the foetus. The cerebral cortex of the foetus depends on maternal thyroxine (T 4 ) for the production of the 3 0 ,3,5-tri-iodothyronine (T 3 ) for nuclear receptor-binding and biological effectiveness. Maternal hypothyroxinemia early in pregnancy is potentially damaging for foetal brain development. Direct evidence has been obtained from experiments on animals: even a relatively mild and transient hypothyroxinemia during corticogenesis, which takes place mostly before mid-gestation in humans, affects the migration of radial neurons, which settle permanently in heterotopic locations within the cortex and hippocampus. Behavioural defects have also been detected. The conceptus imposes important early changes on maternal thyroid hormone economy that practically doubles the amount of T 4 secreted something that requires a concordant increase in the availability of iodine, from 150 to 250-300 mg I day 21 . Women who are unable to increase their production of T 4 early in pregnancy constitute a population at risk for having children with neurological disabilities. As a mild to moderate iodine deficiency is still the most widespread cause of maternal hypothyroxinemia, the birth of many children with learning disabilities may be prevented by advising women to take iodine supplements as soon as pregnancy starts, or earlier if possible, in order to ensure that their requirements for iodine are met.

Measuring serum Tg and performing a diagnostic whole body scan (DxWBS) has become the standard for follow-up of patients with differentiated thyroid carcinoma. The primary aim of this study was to determine whether recombinant human TSH (rhTSH)-stimulated Tg alone is sufficiently sensitive to identify residual cancer in patients with no clinical evidence of disease and undetectable or very low serum Tg levels during thyroid hormone (TH) therapy. A secondary aim was to investigate the frequency of tumor in such patients. One hundred and seven consecutive patients, aged 10.9 -85.3 yr (median, 36.3), at the time of initial surgery who had Tg levels on TH therapy that were undetectable (95% <0.5 ng/ml) or low (4% 0.6 ng/ml, 1% 1.0 ng/ml) and who underwent rhTSHstimulated testing 10 months to 35 yr (median, 3.5 yr) after initial thyroidectomy and 131 I ablation were retrospectively studied. Many (50%) were at high risk of tumor recurrence, and 5 had distant metastases during the course of their disease. In response to rhTSH, Tg ranged from 0.5 or less to 17.9 ng/ml, remaining at 0.5 ng/ml or less in 68 (64%) patients and increasing to levels between 0.6 and 2 ng/ml in 19 (18%) others and to levels higher than 2 ng/ml in 20 (19%) patients. Eleven patients (10%), all of whom had rhTSH-stimulated serum Tg levels above 2 ng/ml, were found to have persistent tumor in lung (4 patients), lymph nodes (5 patients, 3 with cervical central compartment, 1 bilateral cervical, and 1 with mediastinal nodes) identified by fine needle cytology, surgical pathology, posttherapy whole body scans, or computed tomography and, in two patients, with high serum Tg values alone (4.6 and 7.0 ng/ml after rhTSH and, respectively, 28.5 and 70.6 ng/ml after TH withdrawal), although in neither could the tumor site be identified. Thirteen patients (12%) were treated with surgery or 131 I, and in some cases both, as a result of the rhTSH studies; 10 had tumor, 1 had residual uptake in the thyroid bed visible on rhTSH-stimulated diagnostic whole body scan (DxWBS), and 2 had high serum Tg levels, presum-ably originating from a tumor site that could not be identified. A patient's tumor status, even in retrospect, usually was not predictable on the basis of Tg during TH therapy or tumor node metastasis status: among patients found to have tumor after rhTSH, serum Tg during TH therapy was 0.5 ng/ml or less in 55% and 0.6 ng/ml in 36%, and tumor node metastasis status was T2N1 or less in 82%. In no case did the rhTSH-stimulated DxWBS show the site of persistent tumor. There were correlations between visible thyroid bed uptake on DxWBS and quantitated 131 I uptake (r 2 ‫؍‬ 0.11; P ‫؍‬ 0.001), between DxWBS and rhTSH-stimulated Tg (r 2 ‫؍‬ 0.54; P ‫؍‬ 0.001), and between rhTSH-stimulated Tg and 131 I uptake (r 2 ‫؍‬ 0.66; P ‫؍‬ 0.0001). There was no statistically significant difference (P ‫؍‬ 0.4) in bed 131 I uptake in patients with rhTSH-stimulated serum Tg levels of 0.5 ng/ml or less compared with that in subjects with higher rhTSH-Tg levels. An rhTSH-stimulated Tg level greater than 2 ng/ml had a sensitivity of 100%, a negative predictive value of 100%, and a false positive rate of 9%. The rhTSH Tg had a substantially better performance than the other studies; the false negative rates were 64% for Tg higher than 0.5 ng/ml on TH therapy, 73% for rhTSH-stimulated DxWBS showing uptake, and zero for an rhTSH-stimulated Tg more than 2 ng/ml. In conclusion, of 107 patients who were clinically free of disease, 10% had persistent tumor (4 with pulmonary metastases and 5 with regional disease) that was only identified with an rhTSH-stimulated serum Tg level greater than 2 ng/ ml. This study shows that tumor amenable to early therapy may be found when rhTSH-stimulated serum Tg rises above 2 ng/ml without performing a DxWBS, which merely provides data concerning the completeness of thyroid ablation, but not persistent tumor. An elevated rhTSH-stimulated Tg greater than 2 ng/ml warrants further study. (

In the past decade, due to a growing awareness of the importance of air quality and air pollution control, many diagnostic tools and techniques have been developed to detect and quantify the concentration of pollutants such as NO x , SO x , CO, and CO 2 . We present here an Incoherent Broad-Band Cavity-Enhanced Spectroscopy (IBB-CEAS) setup which uses a LED emitting around 625 nm for the simultaneous detection of NO 2 and NO 3 . The LED light transmitted through a high finesse optical cavity filled with a gas sample is detected by a low resolution spectrometer. After calibration of the spectrometer with a NO 2 reference sample, a linear multicomponent fit analysis of the absorption spectra allows for simultaneous measurements of NO 2 and NO 3 concentrations in a flow of ambient air. The optimal averaging time is found to be on the order of 400 s and appears to be limited by the drift of the spectrometer. At this averaging time the smallest detectable absorption is 2×10 −10 cm −1 , which corresponds to detection limits of 600 pptv for NO 2 and 2 pptv for NO 3 . This compact and low cost instrument is a promising diagnostic tool for air quality control in urban environments.

The emerging public health importance of zinc and selenium and the continuing public health challenges of iron and iodine draw attention to the unmet need for improved biomarkers of trace element status. Currently available biomarkers of these four trace elements are critiqued including the outstanding lack of satisfactory biomarkers for the assessment of zinc intake and status. Other trace elements are reviewed briefly including copper, for which human dietary deficiencies and excesses have been documented, and chromium, which is of possible but unconfirmed public health significance. Evolving strategies of considerable potential include molecular techniques such as the measurement of metallothionein mRNA in lymphocytes as a biomarker of zinc status, an assay that can now be performed with a dried blood spot. The judicious application of tracer techniques also has a role in advancing the quality of zinc biomarkers. Also of special current interest is full definition of the potentia...

150 mg iodine are daily required for thyroid hormone synthesis. The thyroid gland has intrinsic mechanisms that maintain normal thyroid function even in the presence of iodine excess. Large quantities of iodide are present in drugs, antiseptics, contrast media and food preservatives. Iodine induced hyperthyroidism is frequently observed in patients affected by euthyroid iodine deficient goiter when suddenly exposed to excess iodine. Possibly the presence of autonomous thyroid function permits the synthesis and release of excess quantities of thyroid hormones. The presence of thyroid autoimmunity in patients residing in iodine-insufficient areas who develop iodine-induced hyperthyroidism has not been unanimously observed. In iodine-sufficient areas, iodine-induced hyperthyroidism has been reported in euthyroid patients with previous thyroid diseases. Euthyroid patients previously treated with antithyroid drugs for Graves' disease are prone to develop iodine-induced hyperthyroidism. As well, excess iodine in hyperthyroid Graves' disease patients may reduce the effectiveness of the antithyroid drugs. Occasionally iodine-induced hyperthyroidism has been observed in euthyroid patients with a previous episode of post-partum thyroiditis, amiodarone destructive or type II thyrotoxicosis and recombinant interferon-a induced destructive thyrotoxicosis. Amiodarone administration may induce thyrotoxicosis. Two mechanisms are responsible for this condition. One is related to excess iodine released from the drug, approximately 9 mg of iodine following a daily dose of 300 mg amiodarone. This condition is an iodineinduced thyrotoxicosis or type I amiodarone-induced thyrotoxicosis. The other mechanism is due to the amiodarone molecule that induces a destruction of the thyroid follicles with a release of preformed hormones. This condition is called amiodarone-induced destructive thyrotoxicosis or type II thyrotoxicosis. Patients developing type I thyrotoxicosis in general have preexisting nodular goiter whereas those developing type II thyrotoxicosis have a normal thyroid gland. The latter group of patients, after recovering from the destructive process, may develop permanent hypothyroidism as the consequence of fibrosis of the gland.