Charge Compensation by Iodine Covalent Bonding in Lead Iodide Perovskite Materials

Metal halide perovskite materials (MHPs) are a family of next-generation semiconductors that are enabling low-cost, high-performance solar cells and optoelectronic devices. The most-used halogen in MHPs, iodine, can supplement its octet by covalent bonding resulting in atomic charges intermediate to I− and I0. Here, we examine theoretically stabilized defects of iodine using density functional theory (DFT); defect formation enthalpies and iodine Bader charges which illustrate how MHPs adapt to stoichiometry changes. Experimentally, X-ray photoelectron spectroscopy (XPS) is used to identify perovskite defects and their relative binding energies, and validate the predicted chemical environments of iodine defects. Examining MHP samples with excess iodine compared with near stoichiometric samples, we discern additional spectral intensity in the I 3d5/2 XPS data arising from defects, and support the presence of iodine trimers. I 3d5/2 defect peak areas reveal a ratio of 2:1, matching the number of atoms at the ends and middle of the trimer, whereas their binding energies agree with calculated Bader charges. Results suggest the iodine trimer is the preferred structural motif for incorporation of excess iodine into the perovskite lattice. Understanding these easily formed photoactive defects and how to identify their presence is essential for stabilizing MHPs against photodecomposition.

Excess Iodine Exposure Acutely Increases Salivary Iodide And Antimicrobial Hypoiodous Acid Concentrations In Humans

The lactoperoxidase (LPO)-hydrogen peroxide-halides reaction (LPO system) converts iodide and thiocyanate (SCN-) into hypoiodous acid (HOI) and hypothiocyanite (OSCN-), respectively. Since this system has been implicated in defense of the airways and oropharynx from microbial invasion, we measured the concentrations of these analytes in human saliva before and after iodine administration to test the hypothesis that an iodide load increases salivary iodide and HOI concentrations. Salivary iodide, SCN-, HOI and OSCN- were measured using standard methodology. Salivary iodide and HOI levels significantly increased after iodinated contrast injection compared with baseline levels, whereas there was no significant change in salivary SCN- and OSCN- levels. The contrast dye iodine load and changes of salivary iodide and HOI levels were positively correlated, suggesting that higher iodide in the circulation increases iodide output and salivary HOI production. Excess iodine exposure in humans increases the salivary output of iodide, increasing salivary HOI concentrations with no effect on SCN-/OSCN- levels. This first of its kind study suggests that a sufficient but safe iodide supplementation may augment the generation of antimicrobial HOI by the salivary LPO system against airborne viral pathogens, including coronaviruses and influenza viruses, a possible inexpensive means of effectively curbing viral pandemics.

Study of Urinary Iodine Level Assessment and its Relation to Thyroid Function during Pregnancy

Background The global effort to prevent iodine deficiency disorders through iodine supplementation, such as universal salt iodization, has achieved impressive progress during the last few decades. However, iodine excess, due to extensive environmental iodine exposure in addition to poor monitoring, is currently a more frequent occurrence than iodine deficiency. Iodine excess is a precipitating environmental factor in the development of autoimmune thyroid disease. Aim of the study to evaluate the urinary iodine level as a marker of iodine status in pregnant women in 3rd trimester and assess its relation to thyroid functions. Patients and Methods This Cross Sectional Study was conducted on 100 subjects with their ages ranging from 18-35 years old, pregnant females, at the third trimester, selected from Obstetric Out- patient Clinic of Ain shams University Hospitals. Samples were collected from participants in cairo, during the Spring and Summer from March to August. Results in our study, there was a significant negative correlation between Urinary Iodine level and TSH as Iodine difficient group has the Highest TSH, and the Highest Thyroid Volume, as there was a significant negative correlation between Urinary Iodine level and Thyroid Volume. Conclusion TSH level and Thyroid Volume were global effort to prevent iodine deficiency disorders through iodine supplementation, such as universal salt iodization, has achieved impressive progress during the last few decades. However, iodine excess, due to extensive environmental iodine exposure in addition to significantly higher in Iodine difficient group than Excess iodine group, And FT4 level was lower in Iodine difficient group than excess iodine group.

Factors associated with inadequate urinary iodine concentration among pregnant women in Mbeya region Tanzania.

Background: Deficient and excess iodine intake during pregnancy can lead to serious health problems. In Tanzania, information available on iodine status during pregnancy is minimal. The aim of this study was to assess the iodine status and its association with sociodemographic factors in pregnant women in the Mbeya region, Tanzania. Method: A cross sectional survey involving 420 pregnant women (n=420) aged between 15-49 years registered in antenatal care clinics was conducted. Data were collected via interviews and laboratory analysis of urinary iodine concentration (UIC). Results: Median UIC was 279.4μg/L (+/-26.1) to 1915μg/L. Insufficient iodine intake (UIC below 150μg/L) was observed in 17.14% of participants, sufficient intake in 24.29% and 58.57% had intakes above the recommended level (>250μg/L). Rungwe district council (DC) had the highest proportion of patients (27.9%) with low iodine levels, while Chunya and Mbarali DCs had the greatest proportion of those with UIC’s, over the WHO recommended level. Fish consumption and education status were associated with increased risk of insufficient iodine while individuals in Mbalali DC aged between 35-49 years were associated with increased risk of UIC above recommended level. Conclusion: Both deficient and excess iodine intake remains a public health problem, especially in pregnant women in Tanzania. Therefore, educational programs on iodine intake are needed to ensure this population has an appropriate iodine intake to prevent any health risks to the mother and the unborn child.

“Fueling the Fire” - Irish Sea-Moss Resulting in Jod-Basedow Phenomenon in a Patient With Grave’s Disease

Background: Jod-Basedow phenomenon is a rare cause of thyrotoxicosis due to excess iodine intake. Herbal supplements containing sea-moss have high iodine amount which may precipitate thyrotoxicosis in patients with underlying Grave’s disease or autonomous thyroid nodules. Clinical Case: A seemingly healthy 28-year-old female presented to the ED with chief complaint of fatigue with associated anxiety, palpitations and weight loss. On admission her temperature was 100.4 F, pulse 126 bpm and blood pressure 116/56 mmHg. Exam was unremarkable for thyroid goiter or orbitopathy. Labs revealed WBC count 3.4 x103/µL (ref range 4.0-11.0) with neutropenia, hemoglobin 4.3 g/dL (11.7-15.7), platelet 49 x103/µL (150-450). Liver transaminases (AST, ALT, and alkaline phosphatase) were elevated with levels up to 4 times the upper limit of normal. She was diagnosed with hemolytic anemia secondary to severe Vitamin B12 deficiency due to pernicious anemia. TSH was <0.01 mIU/L (0.27-4.20), free T4 2.46 ng/dL (0.8-1.9) and total T3 139 ng/dL (76-181). The patient subsequently endorsed remote history of hyperthyroidism diagnosed 7 years ago however she could not recall the underlying etiology or the name of medication she was treated with. She reportedly stopped this medication after 1 month due to developing goiter. She also endorsed intermittent use of store-bought supplement of Irish sea moss and bladderwrack in last 2 years. Further workup revealed elevated TSI and TBII antibody titers establishing diagnosis of Grave’s disease. Thyroid ultrasound showed normal sized heterogeneous hypervascular gland with no nodules. I-123 thyroid uptake and scan showed diffuse moderately elevated radioiodine uptake of 16.8% and 40.8% at 4 and 24 hours, respectively. Thionamide therapy was withheld due to concern of neutropenia and transaminitis. She was treated with beta-blocker after which her vital signs normalized. Labs 1 week after stopping sea moss showed TSH 0.01 mIU/L and free T4 1.4 ng/dL. Conclusion: Irish sea moss is a readily available herbal supplement with high, variable amounts of iodine. Despite little scientific evidence, it is often marketed to improve goiter amongst other health benefits. The recommended daily iodine intake per the FDA is 150 mcg. Higher amounts are expected to initially cause a short-lived suppression of thyroid function; the Wolff-Chaikoff effect, followed by “escape” and accelerated production of thyroid hormone in abnormal thyroid gland, known as Jod-Basedow phenomenon. In our case, the patient unknowingly worsened her underlying Grave’s disease due to the Jod-Basedow effect. Of note, apparantly she had a longer than expected course of Wolff-Chaikoff effect preceding the thyrotoxic state due to sporadic irregular intake of sea moss. Discontinuing sea moss led to clinical and biochemical improvement of hyperthyroidism without requiring thionamide therapy.

Iodoral-Induced Iatrogenic Hypothyroidism

Background: Iodine is essential for the formation of thyroid hormones. Therefore, the thyroid gland is generally able to maintain normal hormone synthesis despite changes in iodine availability. When there is an increase in iodide load, the thyroid gland is able to inhibit the formation of organic iodide via the Wolff-Chaikoff effect (WCE). This prevents the formation of large quantities of thyroid hormones, thus preventing hyperthyroidism1. Continued exposure to excess iodine is also overcome by the “escape” phenomenon and hormone synthesis resumes in a normal fashion2. However, some patients may lack this autoregulation and develop hypothyroidism. Clinical Case: An 86-year-old male with a history of subclinical hypothyroidism initially presented to his PCP for evaluation of cognitive decline. Workup revealed a TSH of 10 mcIU/mL (0.34 – 5.6 mcIU/mL), a normal FT4 and a negative TPOAb. It was subsequently revealed that the patient was started on Iodoral 12.5 mg daily, an iodine/potassium iodide supplement, 1 month prior to presentation by a naturopathic doctor. Prior to all this, his TSH had always ranged between 4 – 6 mcIU/mL for many years. It was recommended that he discontinue Iodoral and repeat thyroid labs in the future. Despite this, the patient continued on varying doses of Iodoral supplementation. Repeat labs obtained 8 months later revealed an elevated TSH of 99 mcIU/mL and a low FT4 of 0.43 ng/mL (0.6 – 2.6 ng/mL). Despite these numbers, he was asymptomatic and did not exhibit any overt signs of hypothyroidism. He was referred to Endocrinology and finally stopped taking Iodoral.7 weeks post-discontinuation, his repeat labs showed a resolution of hypothyroidism and return to his baseline subclinical disease with a TSH of 8.2 mcIU/mL and a normal FT4. A urine iodine/creatinine was normal at 244.2 ug/g (35 – 540 ug/g) indicating that there was no residual iodine excess from the Iodoral. Conclusion: As far as we are aware, we present the first reported case of Iodoral-induced iatrogenic hypothyroidism. As with past cases of iodine-induced hypothyroidism, our patient had underlying thyroid disease in subclinical hypothyroidism which could explain why he was unable to escape from the WCE. The half-life of Iodoral is unknown but it is generally understood that the effects of iodide are reversed between 2 to 4 weeks after withdrawal. Our patient did not repeat his thyroid function tests until 7 weeks post-discontinuation but did demonstrate a return to baseline with no other intervention. Reference: 1. Markou K, Georgopoulos N, Kyriazopoulou V, Vagenakis AG. Iodine-Induced hypothyroidism. Thyroid. 2001 May;11(5):501-10. doi: 10.1089/105072501300176462. PMID: 11396709.2. Torti JF, Correa R. Potassium Iodide. 2020 Oct 12. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan–. PMID: 31194460.

Iodine, Seaweed, and the Thyroid

<b><i>Backgound:</i></b> Even a minor iodine deficiency can result in adverse thyroidal health consequences while excess iodine intake can also result in thyroid function disorders. One source of iodine is seaweed which as a foodstuff is enjoying an increasing profile in Western countries. Apart from its potential involvement in thyroidal health, gaseous iodine released from seaweeds plays a significant role in influencing coastal climate through cloud formation. <b><i>Summary:</i></b> Sources of dietary iodine, its assessment, recommended dietary intake, and consequences of iodine excess are outlined. The benefits and possible dangers of dietary intake of iodine-rich seaweed are described. Studies linking seaweed intake to breast cancer prevalence are discussed as is the role of gaseous iodine released from seaweeds influencing weather patterns and contributing to iodine intake in coastal populations. <b><i>Key Messages:</i></b> Universal salt iodization remains the optimum method of achieving optimum iodine status. Promoting increased dietary iodine intake is recommended in young women, in early pregnancy, and in vegan and vegetarian diets. Even where iodine intake is enhanced, regular assessment of iodine status is necessary. Caution against consumption of brown seaweeds (kelps) is required as even small amounts can have antithyroid actions while product labelling may be insufficient. Gaseous iodine produced from seaweeds can have a significant effect on cloud formation and associated global warming/cooling. Increased overall iodine deposition through rainfall and apparent uptake in populations dwelling in seaweed-rich coastal regions may provide a partial natural remedy to global iodine deficits.

Thyroid Function of Infants Breastfed by Mothers with Graves Disease Treated with Inorganic Iodine: A Study of 100 Cases

Context We previously reported that inorganic iodine therapy in lactating women with Graves disease (GD) did not affect the thyroid function in 25 of 26 infants despite their exposure to excess iodine via breast milk. Objective To further assess thyroid function in infants nursed by mothers with GD treated with inorganic iodine. Design Case series Setting Tajiri Thyroid Clinic, Japan Participants One hundred infants of lactating mothers with GD treated with potassium iodide (KI) for thyrotoxicosis Main Outcome Measures Infant blood thyrotropin (TSH) and free thyroxine (FT4) levels were measured by the filter paper method. Subclinical hypothyroidism was defined as TSH ≥10 μIU/mL and ≥5 μIU/mL in infants aged &lt;6 and ≥6 months, respectively. Results Overall, 210 blood samples were obtained from 100 infants. The median infant age was 5 (range, 0-23) months; median maternal KI dose, 50 (4-100) mg/day; median blood TSH level, 2.7 (0.1-12.3) μIU/mL; and median blood FT4 level, 1.04 (0.58-1.94) ng/dL. Blood TSH level was normal in 88/100 infants. Twelve infants had subclinical hypothyroidism; among them, blood TSH levels normalized after maternal KI withdrawal or stopping breastfeeding in 3 infants. In 7 infants, blood TSH levels normalized during KI administration without stopping breastfeeding. Two infants could not be followed up. Conclusion In Japan, inorganic iodine therapy for lactating women with GD did not affect thyroid function in most of the infants. Approximately 10% of infants had mild subclinical hypothyroidism, but blood TSH level normalized during continued or after discontinuing iodine exposure in all followed up infants.