Thyroid Iodine Content Research Articles

Effect of bisphenol S and bisphenol A on morphometric and hormonal changes of thyroid gland and iodine concentration in urine of Wistar rats

Effect of bisphenol S and bisphenol A on morphometric and hormonal changes of thyroid gland and iodine concentration in urine of Wistar rats

Thyroid Hormone Concentrations in Testudo spp. by Season and Sex

Thyroid hormones and the factors influencing them are rarely studied in tortoises. This study therefore aimed to calculate reference intervals (RI) for thyroid hormones and iodine concentrations by species, sexes, and seasons in four species of adult Mediterranean tortoises (Testudo spp.) and to evaluate possible correlations between plasma thyroid hormones, serum iodine, plasma protein, and increased liver and kidney values. Thyroid hormones (total tetraiodothyronine [tT4], free tetraiodothyronine [fT4], total triiodothyronine [tT3], and free triiodothyronine [fT3]) were measured in plasma from adult, healthy Hermann's (Testudo hermanni, n = 255), spur-thighed (Testudo graeca, n = 89), marginated (Testudo marginata, n = 72), and Russian tortoises (Testudo horsfieldii, n = 30). Species, sex, and seasonal variations were determined by Bayesian information criterion (BIC), and correlations between thyroid hormones, protein, iodine, and increased liver/kidney values were evaluated by Spearman's rank correlation test. Total T4 did not reveal any species, sex, or seasonal differences (RI: 0.102–0.455 µg/dl), while seasonal differences were found for fT4 (RI: spring 0.624–9.012; summer 0.379–5.476; fall 0.376–5.426 pmol/L). The tT3 concentrations differed significantly depending on species, season, and the interaction of species × season. Seasonal differences were also found for fT3 and iodine. Several significant (P ≤ 0.05) correlations were detected between the analytes, including a positive correlation between tT4 and fT4. These results provide a tool for the evaluation of thyroid hormone concentrations in Mediterranean tortoises and confirm the influence of season on thyroid function in these animals.

Schmallenberg virus infection suspected in a calf born to an imported heifer.

Schmallenberg virus infection suspected in a calf born to an imported heifer.

Effect of high-nitrate beetroot juice consumption on thyroid gland hormones and iodine levels in adults

Dietary nitrate supplementation has been widely investigated by the scientific community due to its beneficial effects on the cardiovascular system. However, there is evidence suggesting a possible effect of nitrate in scavenger iodine from the thyroid gland, which may affect thyroid hormone synthesis. Therefore, this study evaluated the effect of seven days of a nitrate-rich beetroot juice supplementation on thyroid hormones and iodine concentrations in healthy adults. Thirteen healthy adults were enrolled in a randomized, double-blind, crossover and placebo-controlled study. Participants ingested 140 mL of nitrate-rich beetroot juice (8.12 ± 3.61 mmol/day) or placebo (nitrate-depleted BJ) during one week. Before and after the supplementation period, blood and urine were drawn for analysis of thyroid hormones, iodine, nitrate and nitrite. No significant changes were observed in plasma triiodothyronine, thyroxine, nitrate and nitrite, and urinary iodine concentrations. In conclusion, these results suggest that one-week supplementation with a nitrate-rich beetroot juice intake does not affect thyroid function.

Controversy in the content and action of human extrathyroidal iodine

Total body iodine (I) content was reported in many studies of medical literature. But only thyroidal iodine content has been well estimate (by fluorescent scanning) in the normal human thyroid and now well established ( 5–15 mg). Similar methods was not available for other tissues and extrathyroidal organs. Many researchers reported different numbers of 10 -50 mg of total iodine content of human body. The Author in his researches reported different numbers from 60% to 70% of the total extrathyroidal iodine amount, and in this paper he summarizes the most evident figures from medical literature of radio-iodine in some extrathyroidal organs. The action of extrathyroidal iodine is an important new area of investigation, which might be useful for the study of carcinogenesis, apoptosis, immunity, atherosclerosis, antioxidant function and other neurological and degenerative diseases. The high and persistent I-uptake of aorta and arterial walls explain the antiatherosclerotic activity of iodine. Iodine is also important for the study of life and human evolution.

Iodine concentration and content measured by dual-source computed tomography are correlated to thyroid hormone levels in euthyroid patients: a cross-sectional study in China

BackgroundThe aim of this study was to investigate the correlation of the dual energy CT measured iodine concentration and total iodine content with blood measured thyroid parameters.MethodsForty-three patients with normal thyroid function at our hospital from August 2017 to October 2019 were included in this retrospective study. Dual energy CT was used to scan the neck of thyroid patients. The mean iodine concentration and thyroid tissue volume were measured to calculate the total iodine content of the thyroid. Relevant tests of triiodothyronine (FT3), total triiodothyronine (TT3), total thyroxine (TT4), free thyroxine (FT4), and thyroid hormone (TSH) were conducted. The correlation of the thyroid mean iodine concentration and total iodine content with blood-measured thyroid function was analysed.ResultThe total iodine content in the thyroid was positively correlated with FT3 but negatively correlated with TSH. The mean iodine concentration of the thyroid was positively correlated with both FT3 and TT3.ConclusionThe thyroid iodine content measured by dual energy CT can be used to determine the human iodine nutritional status and evaluate thyroid function, which will facilitate the diagnosis and treatment of thyroid diseases.

The joint role of thyroid function and iodine concentration on gestational diabetes risk in a population-based study.

Iodine is essential for thyroid function, and iodine deficiency during pregnancy is common in Europe and the USA. However, no published studies have examined the role of iodine deficiency in the relation between thyroid function and gestational diabetes mellitus (GDM). We conducted a population-based, nested case-control study within the Finnish Maternity Cohort using pregnancy and perinatal outcome data from the Finnish Maternal Birth Register. We randomly selected 224 GDM cases with singleton pregnancies and 224 controls without GDM from all singleton births occurring in Finland during 2012-2013. Blood was drawn at 10-14weeks' gestation and analyzed for serum iodide, thyroglobulin, and thyroid-stimulating hormone (TSH) concentrations. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CI) of GDM. Very high thyroglobulin concentration (>95% percentile; >83μg/L) was not associated with significantly altered odds of GDM compared to those with normal levels (OR 0.41; 95% CI: 0.12, 1.38). High concentrations of TSH were also not associated with increased odds of GDM compared to normal levels of TSH (OR 0.45; 95% CI: 0.06, 3.18). Women in the lowest 5th percentile (<1.58ng/mL) of iodine did not have increased odds of GDM compared to those with iodide in the highest quartile (OR 0.39; 95% CI: 0.11, 1.35). Low levels of iodide and thyroid function in early pregnancy are not associated with increased risk of GDM in this mildly iodine-deficient population.

Concept and validation of a simple model of the intrathyroidal iodine kinetics

AIM of this study is the introduction and validation of a simple model of the intrathyroidal iodine kinetics, designed for optimizing radioiodine therapy planning and dose measurement in a routine clinical setting. The new model defines the intrathyroidal iodine kinetics as balance of the thyroidal iodine intake and -excretion, characterized by the two exponential equations A(t) = A(0) * (1-exp(-lambda(1) t)) and A(t) = A(0) * (exp(-lambda(2) t) -1), respectively. A(0) describes the theoretically maximum iodine uptake when the thyroidal iodine excretion is ignored, lambda(1) and lambda(2) represent the constants characterizing the iodine intake and excretion, respectively. The thyroidal iodine content at the time t equals the sum of both functions, which is A(t) = A(0) * (exp(-lambda(2) t)-exp(-lambda(1) t)). In 25 patients with autonomous goiter / nodules (n = 18), Graves' disease (n = 5), or endemic euthyroid goiter (n = 2), the iodine uptake in the thyroid during the radioiodine therapy as fraction of the applied activity was determined daily, with the remaining body covered by a lead shield. On average, 7.2 measurements were performed per patient (minimum 4, maximum 13). With these uptake values, individual regression curves were fitted using the above equation, and the difference between the actual measurements and the corresponding values of the regression curves was determined. The average deviation of the 179 uptake values from the calculated points of the respective regression curves was only 1.4%. There was no significant difference between the three disease groups. The distribution of the relative deviations during the individual courses was constant, systematic errors were not detected. Our results suggest that the intrathyroidal iodine kinetics can be precisely described with the model A(t) = A(0) * (exp(-lambda(2) t)-exp(-lambda(1) t)). With only three measurements, the trend of the curve can be calculated, which allows to determine the total radioiodine storage in the thyroid.

Effects of Geophagy on Hemoglobin Level and Iodine Absorption /Assimilation in Albino Rats

Geophagic behaviour has been reported to increase exposure to Lead (Pb) that could influence the bioavailability and assimilation of iron and iodine through metal-metal interactions. Similarly, calcium that is naturally contained in kaolin tends to inhibit the absorption and assimilation of iron. In order to investigate these interactions 80 female albino rats aged 12 weeks and weighing between 212-261g were served with Pb contaminated kaolin pellets in a manner to simulate human consumption of this clay. The size, content of the thyroid gland in iodine, urinary/faecal iodine excretion and hemoglobin level were analytically monitored during this experiment and statgraphic 5.0 used for data analyses. The results show increased thyroid volume, decreased thyroid iodine content, increased urinary iodine excretion and adequate iodine absorption as kaolin is introduced into an iodine sufficient diet. Hemoglobin levels of the various test groups compared to the control group are statistically significant. The study reveals that that kaolin-eating does not influence iodine absorption but, it influences its assimilation at the level of the thyroid gland in albino rats. The study also reveals that the consumption of kaolin affects hemoglobin level.

Evaluation of energy spectrum CT for the measurement of thyroid iodine content.

BackgroundThis study aims to provide a reference for the diagnosis of iodine deficiency disorder by evaluating the normal thyroid iodine content by energy spectrum computed tomography (CT) and calculating the iodine content ratio of thyroid to sternocleidomastoid.MethodsThe thyroid glands of 226 patients were scanned by energy spectrum CT, and the images were analyzed using the GSI Viewer software. Based on the imaging findings, the iodine levels of the thyroid lobes as well as the bilateral sternocleidomastoids were evaluated, and their iodine content ratios were calculated.ResultsNo statistically significant difference was found in the thyroid iodine content between the left and right thyroid lobes (p > 0.05). However, there was a significant difference in the thyroid iodine content between men and women (p < 0.01). Additionally, the thyroid iodine content was found to decrease gradually with age. The iodine content ratio of thyroid to sternocleidomastoid was 96.6271 ± 33.2442.ConclusionGemstone energy spectrum CT can be used for the measurement of thyroid iodine content in the human body. It can play a significant role in the diagnosis of iodine deficiency disorder.

In Pursuit of Genes of Glucose Metabolism

If you don't know where you're going, you might wind up someplace else—Yogi Berra My professional journey, once I accepted the fact that I would not play first base for the Chicago Cubs, was not accomplished in a straight line. I entered medical school intending to become a family physician but soon became interested in research. I took an internal medicine residency at the University of California, San Francisco (UCSF), then a long research fellowship in the nascent field of molecular biology at the National Institutes of Health (NIH), and followed that with training in clinical endocrinology at the University of Wisconsin. I spent the next fifteen years dividing my time between the clinic and laboratory at the University of Iowa. Finally, I decided to concentrate on research and spent the next twenty-three years at Vanderbilt University. For the past eleven years, I have been at the University of Iowa, where I helped establish a new diabetes research center. My research journey also had several different directions. Upon reflection, I guess I ended up “someplace else” by choice, and it certainly has been an interesting trip. It is one I unreservedly recommend.

The Effect of Radionuclide Pollution on Thyroid Hormones Levels and Iodine Concentration in the Hair of Children

The Effect of Radionuclide Pollution on Thyroid Hormones Levels and Iodine Concentration in the Hair of Children

Alterations of thyroid volume and nodular size during and after pregnancy in a severe iodine-deficient area.

The effects of pregnancy on thyroid nodules were investigated in a few number of studies. We aimed to evaluate the prevalence of thyroid nodules, the changes in size, volume and number of nodules during pregnancy and after delivery in pregnant women. This prospective study was performed in a severe iodine-deficient area and included 83 pregnant women (mean age 30·4±5·5years). We evaluated thyroid hormone levels, ultrasound examination of thyroid and urine iodine concentration (UIE) at each trimester and at 3-month post-partum period (PP). All patients with thyroid nodules >1cm underwent fine-needle aspiration biopsy (FNAB) after the last visit at the PP. Twenty-six women had thyroid nodules on thyroid ultrasonography at the first trimester. The volume of single/dominant nodule showed enlargement during pregnancy and remained at the PP; however, it was not significant (first trimester: 0·83±0·8ml; second trimester: 0·92±1ml; third trimester: 0·99±1·2ml; PP: 0·92±1·2ml). The maximum diameter of single/dominant nodule in the third trimester of pregnancy (12·6±5·4mm) was greater than the first trimester (11·9±4·8mm) (P=0·002). The number of nodules did not change during pregnancy. The mean TV increased during pregnancy and remained 3months after delivery (P<0·001), and the maximum value of TV was reached in the third trimester (14·2±7·9ml). FNAB results revealed a 6·6% prevalence of malignancy among the nodules. Thyroid nodules were present in 30·1% of pregnant women. While size of the single/dominant thyroid nodule increased significantly during pregnancy, the number of nodules did not change.

Serum and tissue iodine concentrations in rats fed diets supplemented with kombu powder or potassium iodide.

Serum and tissue iodine concentration was measured in rats fed a diet supplemented with powdered kombu (Saccharina sculpera) or potassium iodide to evaluate the absorption of iodine from kombu. Eighteen male 5-wk-old Wistar rats were divided into three groups and fed a basal AIN93G diet (iodine content, 0.2 mg/kg) or the basal diet supplemented with iodine (183 mg/kg) either in the form of kombu powder or potassium iodine (KI) for 4 wk. There were no differences in weight gain or serum biochemistry tests (alanine aminotransferase and aspartate aminotransferase activity, and total serum cholesterol and triglyceride concentration) after iodine supplementation. In addition, serum levels of the thyroid hormones thyroxine and triiodothyronine, as well as thyroid-stimulating hormone, were not affected. On the other hand, serum and tissue (thyroid, liver and kidney) iodine concentrations were markedly elevated after iodine supplementation. There was no difference in thyroid iodine concentration between KI and kombu supplementation. However, there was a significant difference observed in the iodine concentrations of serum, liver and kidney between the two iodine sources; rats fed KI had iodine concentrations in these tissues 1.8 to 1.9 times higher than those in rats fed kombu powder. These results suggest that the absorption of iodine from kombu is reduced compared to that from potassium iodide.

Hypothyroxinemia Induced by Mild Iodine Deficiency Deregulats Thyroid Proteins during Gestation and Lactation in Dams

The main object of the present study was to explore the effect on thyroidal proteins following mild iodine deficiency (ID)-induced maternal hypothyroxinemia during pregnancy and lactation. In the present study, we established a maternal hypothyroxinemia model in female Wistar rats by using a mild ID diet. Maternal thyroid iodine content and thyroid weight were measured. Expressions of thyroid-associated proteins were analyzed. The results showed that the mild ID diet increased thyroid weight, decreased thyroid iodine content and increased expressions of thyroid transcription factor 1, paired box gene 8 and Na+/I− symporter on gestational day (GD) 19 and postpartum days (PN) 21 in the maternal thyroid. Moreover, the up-regulated expressions of type 1 iodothyronine deiodinase (DIO1) and type 2 iodothyronine deiodinase (DIO2) were detected in the mild ID group on GD19 and PN21. Taken together, our data indicates that during pregnancy and lactation, a maternal mild ID could induce hypothyroxinemia and increase the thyroidal DIO1 and DIO2 levels.

An International Delphi Study of the Causes of Death and the Criteria Used to Assign Cause of Death in Bovine Perinatal Mortality

The objective of the present study was to elicit opinion from two groups of veterinarians [subject matter experts and non-subject matter experts] about the causes of bovine perinatal mortality and the criteria used to assign such causes. The subject matter experts were selected on the basis of their scientific publications or experience of working in a veterinary diagnostic or research laboratory in the area of bovine perinatal mortality. The non-subject matter experts were self-selected as cattle veterinarians without particular expertise in bovine perinatology. A total of 74 veterinarians (46 subject matter experts and 28 non-subject matter experts) from 23 countries responded. The study was conducted using Delphi methodology over seven rounds. Respondents were asked to agree the causes of bovine perinatal mortality and for each cause to agree the supporting diagnostic criteria. There was a close agreement between groups on 16 causes of death apart from intra-uterine growth retardation (IUGR) and micronutrient imbalances which were accepted by fewer subject matter experts. There was inter-group consensus on the criteria to diagnose accidents, congenital defects, dystocia, hyperthermia, infections, premature placental separation, prematurity and prolonged calving. There was inter-group consensus on the criteria to diagnose anoxia, apart from gingival cyanosis; on haemorrhage, apart from haemorrhagic anaemia; on IUGR, apart from organ weights; and on iodine imbalance, apart from goitre and thyroid iodine content. The results from this study highlighted the current lack of standardization of the criteria used to define the cause of death for bovine perinatal mortality and the need for such standardization.

Effets de la restriction alimentaire appliquée à des rates adultes sur la croissance osseuse et la structure histologique de la thyroïde chez leurs jeunes

Study purposeOur objective was the study of the development and the maturation of pups whose mothers were subjected to intermittent fasting. Materials and methodsEight pregnant female Wistar rats were distributed into two groups of four adult females. The rats of the first group were subjected to intermittent fasting beginning on the 14th day of gestation and continued 21 days after parturition. The rats of the second group were normally fed. The young of both groups of rats were sacrificed at the age of 21 days. ResultsThe pups of the female rats submitted to food restriction showed a reduction of the body weight (–35%), of the thyroid iodine content (P<0.001) and of segment thyroxin (P<0.05). The histological study revealed that these pups presented colloid depletion of this follicular thyroid, non-anastomosing trabeculae, cortical bone thinning, decreased bone mineral content, absence of osteoid formation and decreased number of osteoclasts. ConclusionDietary restriction imposed on adult rats, from gestation, led to the installation in their pups of a state of malnutrition and a description of thyroid histology. This thyroid abnormality is associated with hypothyroidism that led, at least in part, to the collapse of the ability to regulate bone remodeling.

Oxidative stress and thyroid impairment after gibberellic acid treatment in pregnant and lactating rats and their offspring

Gibberellic acid (GA₃) has been worldwide used in agriculture as a plant growth regulator. The purpose of this study is to assess the effects of GA₃ on the morphology and the thyroid hormone levels in adult rats and their suckling pups. Animals were given daily 200 ppm GA₃ in drinking water from the 14th day of pregnancy until day 14 after delivery. Compared with a control group, GA₃-treated mothers and pups showed an increase in body and thyroid weights, a decrease in plasma FT₄ and FT₃ levels, which were more pronounced in pups than in their mothers. Thyroid iodine content was also decreased in pups. These biochemical modifications corresponded histologically; the majority of follicles had cubical epithelial cells, which surrounded empty vesicular cavities. Toxicity was objectified by a significant increase in plasma malondialdehyde, protein carbonyls, and advanced oxidation protein products levels in GA₃-treated dams and their suckling pups; while, the activities of superoxide dismutase, catalase, and glutathione peroxidase were decreased in plasma of both dams and their pups. Moreover, a significant decline was observed in plasma glutathione, nonprotein thiols, and vitamin C levels. We conclude that GA₃ treatment affects thyroid function and plasma antioxidant status in adult rats and their progeny.

Marginal iodide deficiency and thyroid function: Dose–response analysis for quantitative pharmacokinetic modeling

Severe iodine deficiency (ID) results in adverse health outcomes and remains a benchmark for understanding the effects of developmental hypothyroidism. The implications of marginal ID, however, remain less well known. The current study examined the relationship between graded levels of ID in rats and serum thyroid hormones, thyroid iodine content, and urinary iodide excretion. The goals of this study were to provide parametric and dose–response information for development of a quantitative model of the thyroid axis. Female Long Evans rats were fed casein-based diets containing varying iodine (I) concentrations for 8 weeks. Diets were created by adding 975, 200, 125, 25, or 0 μg/kg I to the base diet (∼25 μg I/kg chow) to produce 5 nominal I levels, ranging from excess (basal + added I, Treatment 1: 1000 μg I/kg chow) to deficient (Treatment 5: 25 μg I/kg chow). Food intake and body weight were monitored throughout and on 2 consecutive days each week over the 8-week exposure period, animals were placed in metabolism cages to capture urine. Food, water intake, and body weight gain did not differ among treatment groups. Serum T4 was dose-dependently reduced relative to Treatment 1 with significant declines (19 and 48%) at the two lowest I groups, and no significant changes in serum T3 or TSH were detected. Increases in thyroid weight and decreases in thyroidal and urinary iodide content were observed as a function of decreasing I in the diet. Data were compared with predictions from a recently published biologically based dose–response (BBDR) model for ID. Relative to model predictions, female Long Evans rats under the conditions of this study appeared more resilient to low I intake. These results challenge existing models and provide essential information for development of quantitative BBDR models for ID during pregnancy and lactation.

X-ray fluorescence analysis (XFA) of thyroidal iodine content (TIC) with an improved measuring system.

X-ray fluorescence analysis is based on the principal that the electron structure of stable iodine in the thyroid is excited by Americium-241 gamma rays to emit a characteristic fluorescence radiation which is proportional to the amount of iodine present in the gland. A stationary measuring system consisting of a 11.1 GBq Am-241 source and a high-purity Germanium detector with spectrum analyser has been improved by a PC guided method for sonographic definition of the measuring volume. The lower limit of detectibility of the system corresponds to 0.01 mg of Iodine per ml of thyroid volume; the in vivo precision given as coefficient of variation amounts to 15%. The thyroid is exposed with a radiation dose of 6 microSv per measurement. First studies with this improved system carried out in 50 female volunteers between 20 and 40 years of age with normal thyroid volumes resulted in a mean iodine concentration of the thyroid of 0.665 +/- 0.304 mg/ml. The mean iodine excretion in urine was normal with 10.8 +/- 10.4 microg/dl.