Rapid alteration in circulating free thyroxine modulates pituitary type II 5\u27 deiodinase and basal thyrotropin secretion in the rat

TSH secretion is decreased by both T4 and T3. This negative feedback control of TSH secretion has been correlated with an increase in pituitary nuclear T3 content, and it is not clear whether T4 exerts its effect directly on the thyrotroph or after its deiodination to T3. However, levels of the pituitary enzyme catalyzing T4 to T3 conversion, 5\u27D-II, are decreased in the presence of an increased amount of T4. Thus, it is unclear why the thyrotroph would have a mechanism for modulating the production of T3, if T3 is, in fact, the sole bioactive signal providing negative feedback inhibition. To examine this apparent paradox, we administered EMD 21388, a compound which inhibits the binding of T4 to transthyretin resulting in a rapid increase in circulating free T4 levels, to rats pretreated with radiolabeled T4 and T3. We observed increases in pituitary and liver T4 content of greater than 150%, without increases in the respective tissue T3 contents. The EMD 21388-treated rats also exhibited a 25% decrease in pituitary 5\u27D-II activity (103.8 +/- 15.8 fmol 125I released.mg protein-1.h-1, vs. control, 137.4 +/- 15.9, mean +/- SE), as did rats treated with sodium salicylate, another compound that inhibits T4-TTR binding (100.8 +/- 7.1). TSH levels significantly decreased 2 h after the administration of EMD 21388. These data demonstrate that despite a T4-mediated decrease in pituitary 5\u27D-II activity, an increase in T4 independently decreases TSH secretion

Seaweed and Soy: Companion Foods in Asian Cuisine and Their Effects on Thyroid Function in American Women

Seaweeds and soy are two commonly eaten foods in Asia. Both have been reported to affect thyroid function, seaweed because of its iodine content and soy because of its goitrogenic effect. Twenty-five healthy postmenopausal women (mean age 58 years) completed a double-blinded randomized crossover study. Ten capsules (5 g/day) of placebo or seaweed (Alaria exculenta), providing 475 ug of iodine/day, were consumed daily for 7 weeks. A powdered soy protein isolate (Solae Co., St. Louis, MO) providing 2 mg of isoflavones/kg of body weight, was given daily during the last week of each treatment arm. On average, this provided 141.3 mg of isoflavones/day and 67.5 g of protein/day. Blood samples and 48-hour urine samples were collected before and after each intervention period, and urinary I/C (ug of iodine/g of creatinine) and serum thyroxine, free thyroxine index, total triiodothyronine, and thyroidstimulating hormone (TSH) were measured. Seaweed ingestion increased I/C concentrations (P \u3c .0001) and serum TSH (P \u3c .0001) (1.69 +/- 0.22 vs. 2.19 +/- 0.22 uU/mL, mean +/- SE). Soy supplementation did not affect thyroid end points. Seven weeks of 5 g/day seaweed supplementation was associated with a small but statistically significant increase in TSH. Soy protein isolate supplementation was not associated with changes in serum thyroid hormone concentrations

Urinary Iodine, Perchlorate, and Thiocyanate Concentrations in U.S. Lactating Women

Background: Iodine is an essential micronutrient for thyroid hormone production. Adequate iodine intake and normal thyroid function are important during early development, and breastfed infants rely on maternal iodine excreted in breast milk for their iodine nutrition. The proportion of women in the United States of childbearing age with urinary iodine concentration (UIC) <50 μg/L has been increasing, and a subset of lactating women may have inadequate iodine intake. UIC may also be influenced by environmental exposure to perchlorate and thiocyanate, competitive inhibitors of iodine transport into thyroid, and lactating mammary glands. Data regarding UIC in U.S. lactating women are limited. To adequately assess the iodine sufficiency of lactating women and potential associations with environmental perchlorate and thiocyanate exposure, we conducted a multicenter, cross-sectional study of urinary iodine, perchlorate, and thiocyanate concentrations in healthy U.S. lactating women. Methods: Lactating women ≥18 years of age were recruited from three U.S. geographic regions: California, Massachusetts, and Ohio/Illinois from November 2008 to June 2016. Demographic information and multivitamin supplements use were obtained. Iodine, perchlorate, and thiocyanate levels were measured from spot urine samples. Correlations between urinary iodine, perchlorate, and thiocyanate levels were determined using Spearman's rank correlation. Multivariable regression models were used to assess predictors of urinary iodine, perchlorate, and thiocyanate levels, and UIC <100 μg/L. Results: A total of 376 subjects (≥125 from each geographic region) were included in the final analyses [mean (SD) age 31.1 (5.6) years, 37% white, 31% black, and 11% Hispanic]. Seventy-seven percent used multivitamin supplements, 5% reported active cigarette smoking, and 45% were exclusively breastfeeding. Median urinary iodine, perchlorate, and thiocyanate concentrations were 143 μg/L, 3.1 μg/L, and 514 μg/L, respectively. One-third of women had UIC <100 μg/L. Spot urinary iodine, perchlorate, and thiocyanate levels all significantly positively correlated to each other. No significant predictors of UIC, UIC <100 μg/L, or urinary perchlorate levels were identified. Smoking, race/ethnicity, and marital status were significant predictors of urinary thiocyanate levels. Conclusion: Lactating women in three U.S. geographic regions are iodine sufficient with an overall median UIC of 143 μg/L. Given ubiquitous exposure to perchlorate and thiocyanate, adequate iodine nutrition should be emphasized, along with consideration to decrease these exposures in lactating women to protect developing infants

A Modeling Framework to Describe the Transmission of Bluetongue Virus within and between Farms in Great Britain

Recently much attention has been given to developing national-scale micro-simulation models for livestock diseases that can be used to predict spread and assess the impact of control measures. The focus of these models has been on directly transmitted infections with little attention given to vector-borne diseases such as bluetongue, a viral disease of ruminants transmitted by Culicoides biting midges. Yet BT has emerged over the past decade as one of the most important diseases of livestock.We developed a stochastic, spatially-explicit, farm-level model to describe the spread of bluetongue virus (BTV) within and between farms. Transmission between farms was modeled by a generic kernel, which includes both animal and vector movements. Once a farm acquired infection, the within-farm dynamics were simulated based on the number of cattle and sheep kept on the farm and on local temperatures. Parameter estimates were derived from the published literature and using data from the outbreak of bluetongue in northern Europe in 2006. The model was validated using data on the spread of BTV in Great Britain during 2007. The sensitivity of model predictions to the shape of the transmission kernel was assessed.The model is able to replicate the dynamics of BTV in Great Britain. Although uncertainty remains over the precise shape of the transmission kernel and certain aspects of the vector, the modeling approach we develop constitutes an ideal framework in which to incorporate these aspects as more and better data become available. Moreover, the model provides a tool with which to examine scenarios for the spread and control of BTV in Great Britain

The lancet weight determines wheal diameter in response to skin prick testing with histamine

BACKGROUND:Skin prick test (SPT) is a common test for diagnosing immunoglobulin E-mediated allergies. In clinical routine, technicalities, human errors or patient-related biases, occasionally results in suboptimal diagnosis of sensitization. OBJECTIVE:Although not previously assessed qualitatively, lancet weight is hypothesized to be important when performing SPT to minimize the frequency of false positives, false negatives, and unwanted discomfort. METHODS:Accurate weight-controlled SPT was performed on the volar forearms and backs of 20 healthy subjects. Four predetermined lancet weights were applied (25 g, 85 g, 135 g and 265 g) using two positive control histamine solutions (1 mg/mL and 10 mg/mL) and one negative control (saline). A total of 400 SPTs were conducted. The outcome parameters were: wheal size, neurogenic inflammation (measured by superficial blood perfusion), frequency of bleeding, and the lancet provoked pain response. RESULTS:The mean wheal diameter increased significantly as higher weights were applied to the SPT lancet, e.g. from 3.2 ± 0.28 mm at 25 g to 5.4 ± 1.7 mm at 265 g (p<0.01). Similarly, the frequency of bleeding, the provoked pain, and the neurogenic inflammatory response increased significantly. At 265 g saline evoked two wheal responses (/160 pricks) below 3 mm. CONCLUSION AND CLINICAL RELEVANCE:The applied weight of the lancet during the SPT-procedure is an important factor. Higher lancet weights precipitate significantly larger wheal reactions with potential diagnostic implications. This warrants additional research of the optimal lancet weight in relation to SPT-guidelines to improve the specificity and sensitivity of the procedure

International Consensus Statement on Rhinology and Allergy: Rhinosinusitis

Background: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR‐RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR‐RS‐2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence‐based findings of the document. Methods: ICAR‐RS presents over 180 topics in the forms of evidence‐based reviews with recommendations (EBRRs), evidence‐based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results: ICAR‐RS‐2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence‐based management algorithm is provided. Conclusion: This ICAR‐RS‐2021 executive summary provides a compilation of the evidence‐based recommendations for medical and surgical treatment of the most common forms of RS