Tissue Iodine Research Articles

Expression and function of placental uric acid transporter GLUT9

Expression and function of placental uric acid transporter GLUT9

A Quantification Method for Breast Tissue Thickness and Iodine Concentration Using Photon-Counting Detector.

The purpose of contrast-enhanced digital mammography (CEDM) is to facilitate detection and characterization of the lesions in the breast using intravenous injection of an iodinated contrast agent. CEDM produces iodine images with gray levels proportional to iodine concentration at each pixel, which can be considered as quantification of iodine. While dual-energy CEDM requires an accurate knowledge of the thickness of compressed breast for the quantification, it is known that the accuracy of the built-in thickness measurement is not satisfactory. Triple-energy CEDM, which can provide a third image, can alleviate the limitation of dual-energy CEDM. If triple exposure technique is applied, it can lead to increased risk of motion artifact. An energy-resolving photon-counting detector (PCD) that can acquire multispectral X-ray images can reduce the risk of motion artifact. In this research, an easily implementable method for iodine quantification in breast imaging was suggested, and it was applied to the images of breast phantom with various iodine concentrations. The iodine concentrations in breast phantom simulate lesions filled with different iodine concentrations in the breast. The result shows that the proposed method can quantify the iodine concentrations in breast phantom accurately.

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.

Iodine contributes to osmotic acclimatisation in the kelp Laminaria digitata (Phaeophyceae).

Iodide (I⁻) retained by the brown macroalga Laminaria digitata at millimolar levels, possesses antioxidant activities, but the wider physiological significance of its accumulation remains poorly understood. In its natural habitat in the lower intertidal, L. digitata experiences salinity changes and osmotic homeostasis is achieved by regulating the organic osmolyte mannitol. However, I⁻ may also holds an osmotic function. Here, impacts of hypo- and hypersaline conditions on I⁻ release from, and accumulation by, L. digitata were assessed. Additionally, mannitol accumulation was determined at high salinities, and physiological responses to externally elevated iodine concentrations and salinities were characterised by chl a fluorometry. Net I⁻ release rates increased with decreasing salinity. I⁻ was accumulated at normal (35 S A) and high salinities (50 S A); this coincided with enhanced rETRmax and qP causing pronounced photoprotection capabilities via NPQ. At 50 S A elevated tissue iodine levels impeded the well-established response of mannitol accumulation and prevented photoinhibition. Contrarily, low tissue iodine levels limited photoprotection capabilities and resulted in photoinhibition at 50 S A, even though mannitol was accumulated. The results indicate a, so far, undescribed osmotic function of I⁻ in L. digitata and, thus, multifunctional principles of this halogen in kelps. The osmotic function of mannitol may have been substituted by that of I⁻ under hypersaline conditions, suggesting a complementary role of inorganic and organic solutes under salinity stress. This study also provides first evidence that iodine accumulation in L. digitata positively affects photo-physiology.

Lithium Therapy and Thyroid Disorders

Lithium is a first-line treatment for bipolar disorder and is associated with a variety of thyroid toxicities. The pathophysiology is complex but may include inhibiting the formation and release of thyroid hormones, increasing intrathyroidal iodine content, altering the hypothalamus-pituitary axis, and stimulating various cellular pathways such as insulin-like growth factor, tyrosine kinase, and Wnt/β-catenin signaling. Goiter, the most common manifestation,is noted in up to 50% of patients, which is followed by hypothyroidism seen in approximately 20% of patients. The incidence of hyperthyroidism is less frequent in lithium-treated patients but is still higher than in the general population. By decreasing thyroid hormone release, lithium can be used to treat hyperthyroidism, but limited data supporting its effectiveness and lithium’s associated toxicity limit its use to refractory cases only. Lithium can also increase retention of radioactive iodine in thyroid tissue and therefore has the potential to be an adjunct therapy for hyperthyroidism and thyroid cancer, but more research in this area is needed.

Maintenance of iodine intake

Maintenance of iodine intake

Ethiodized Oil Uptake Does Not Predict Doxorubicin Drug Delivery after Chemoembolization in VX2 Liver Tumors

Purpose To investigate the accuracy of ethiodized oil as an imaging marker of chemotherapy drug delivery after liver tumor chemoembolization in an animal model of hepatocellular carcinoma. Materials and Methods Eleven VX2 liver tumors (mean diameter, 1.9 cm ± 0.4) in six New Zealand White rabbits were treated with chemoembolization using ethiodized oil and doxorubicin emulsion, followed by immediate euthanasia. Postprocedure noncontrast computed tomography (CT) was used to evaluate intratumoral ethiodized oil distribution and calculate iodine content within four peripheral tumor quadrants and the tumor core at a central tumor slice (N = 55 total tumor sections). Liquid chromatography/tandem mass spectrometry (LC-MS/MS) was then used to directly measure doxorubicin concentration in the same tissue sections. Statistical correlation was performed between tissue iodine content and doxorubicin concentration by using linear regression. Results Chemoembolization was successfully performed in all tumors via the left or proper hepatic artery. A mean of 0.9 mL ± 0.6 ethiodized oil and 1.8 mg ± 1.2 doxorubicin were injected. CT-calculated tissue iodine content averaged 335 mg/mL ± 218. Corresponding LC-MS/MS analysis yielded a mean doxorubicin concentration of 15.8 μg/mL ± 14.3 in each sample. Although iodine content (391 mg/mL vs 112 mg/mL; P = .000) and doxorubicin concentration (18.0 μg/mL vs 7.2 μg/mL; P = .023) were significantly greater along peripheral tumor sections compared with the tumor core, no significant predictable correlation was evident between these measures ( R 2 = 0.0099). Conclusions Tissue ethiodized oil content is a poor quantitative predictor of local doxorubicin concentration after liver tumor chemoembolization. Future studies should aim to identify a better imaging marker for chemoembolization drug delivery.

Material Decomposition in Contrast-enhanced Digital Mammography Based on Photon Counting: Monte Carlo Simulation Studies

of the photons at 50-kVp. We simulated photons generated at 50 kVp and 11 mAs. We acquired two images, one below and one above the iodine K-edge using one exposure with energy selective windows. The calibration data were obtained for various combinations step wedge phantom of breast tissue equivalent materials and iodine. The images from the calibration phantom were used to produce the inverse mapping functions. Material decomposition was investigated in terms of a contrast-to-noise ratio (CNR). According to the results, the values of the CNR calculated the with dual energy technique were higher than that of a conventional X-ray system. The calculated values of the CNR with the cubic inverse mapping function were 50.082 times higher than those with the linear inverse mapping function for 0.2-mm iodine. The calculated values of the CNR with the quadratic inverse mapping function were 31.840 times higher than those with the linear inverse mapping function for 0.2-mm iodine. We demonstrated that the CdTe photon counting detector could reduce the radiation dose compared to two exposures with the dual energy technique. The calculated radiation dose of the one-exposure method had a 65% lower radiation dose than the dose of the two-exposure method. Our studies may be used as a basis for future studies on room-temperature semiconductor X-ray detectors. Eorts to reduce the errors in the inverse mapping functions and the scatter eects need to be investigated in the future.

The Placenta as a Compensatory Iodine Storage Organ

The production of iodine-containing thyroid hormones necessary for brain development in the fetus depends not only on maternal dietary intake but also on placental iodine transport. The optimum level of iodine nutrition during pregnancy and the proportion of the pregnant population reaching this level have previously been evaluated. Little information exists on the ability of the placenta to either accumulate or store iodine. This study aims to investigate iodine uptake and tissue iodine content within placental tissue obtained from women delivering at term. Samples (∼1 cm(3)) obtained from placental cotyledons (n = 19), thyroid (n = 4), and uterine myometrial (n = 4) tissue were incubated for 6 hours with (125)I in the presence and absence of potassium perchlorate. To account for variation in tissue composition, results were expressed in cpm (125)I/μg DNA. Placental uptake of (125)I (375 cpm/μg DNA) was significantly higher than that of control myometrial tissue (226 cpm/μg DNA) (p < 0.05) and was ∼25% that of thyroid tissue (1702 cpm/μg DNA). Uptake of (125)I could be partially blocked in the thyroid and placenta, respectively, by potassium perchlorate (100 μM), which had no effect on uptake by myometrial tissue. Iodine content of tissue samples measured using an alkaline ashing technique with Sandell-Kolthoff colorimetry gave a mean value for total iodine of 30.4 ng/g placental tissue (range 21-50 ng/g), 1.74 ng/g myometrial tissue, and 1037 ng/g thyroid tissue. Placental iodine content was only ∼3% that of the thyroid, but on the basis that neonatal iodine stores are very low and highly sensitive to fluctuations in maternal iodine supply, we postulate that placental iodine bioavailability makes a significant contribution to protection against neonatal hypothyroidism. These findings suggest that the placenta has a role not only in uptake but also in storing iodine as a possible means of protecting the fetus from inadequacies in maternal dietary iodine intake.

202: The placenta as a significant modulator of iodine supply to the fetus

Iodide supply to the developing fetus is dependent on maternal dietary iodine intake and on functioning placental iodine transport; maternal iodine excretion falls precipitously at delivery. The aim of this study was to evaluate iodide uptake, tissue iodine content and transporter expression in placental tissue obtained from women undergoing prelabor cesarean section (CS) at term. The influences of different pregnancy-associated hormones on placental iodine uptake and its relationship to alterations in the expression levels of the iodide transporters, sodium iodide symporter (NIS) and Pendrin (PDS) were also assessed.

Iodine Content and Distribution in Extratumoral and Tumor Thyroid Tissue Analyzed with X-Ray Fluorescence and Time-of-Flight Secondary Ion Mass Spectrometry

The thyroid's ability to enrich and store iodine has implications for thyroid cancer genesis, progression, and treatment. The study objective was to investigate thyroid iodine content (TIC) in tumoral and extratumoral tissue in patients with papillary thyroid cancer (PTC) as opposed to thyroid healthy controls using two different techniques: X-ray fluorescence (XRF) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). Tissue samples from 10 patients with normal thyroids and 7 patients with PTC were collected. TIC was quantified with XRF, and the iodine stores were located on a histological level with TOF-SIMS. Mean TIC in controls was 0.6 mg/mL (range 0.3-1.2 mg/mL). For the cancer patients, the mean TIC was 0.8 mg/mL (range 0.2-2.3 mg/mL) in extratumoral thyroid tissue, but no iodine was detected in the tumors. TOF-SIMS investigation of the PTC patients showed significantly higher TIC in extratumoral tissue than in tumoral tissue. Iodine in the extratumoral tissue was predominantly located in the follicle lumen with a variation in concentration among follicles. XRF and TOF-SIMS are two complementary methods for obtaining insight into content and localization of iodine in the thyroid. XRF can be used in vitro or in vivo on a large number of samples or patients, respectively. TOF-SIMS on the other hand provides detailed images of the iodine location. The combined information from the two methods is of value for further studies on iodine metabolism in thyroid malignancy.

Dual-energy CT of the heart for diagnosing coronary artery stenosis and myocardial ischemia-initial experience

We aimed to evaluate the feasibility of diagnosing coronary stenosis and myocardial ischemia with a single dual-energy CT (DECT) acquisition. Thirty-five patients underwent contrast-enhanced, ECG-gated DECT of the heart while independently operating the two tubes of a dual-source CT system at high- and low-energy X-ray spectra. From the same raw data, coronary CTA (cCTA) studies were reconstructed for stenosis detection, and the myocardial blood-pool was analyzed by determining the tissue iodine content. Two independent observers analyzed all studies for stenosis and myocardial blood-pool deficits. Results were correlated with SPECT, coronary catheterization and cCTA on a segmental basis. cCTA had 98% sensitivity, 88% specificity and 92% accuracy for detection of >50% stenosis. DECT detected myocardial ischemia with 84% sensitivity, 94% specificity and 92% accuracy. Our initial experience may warrant further exploration of DECT as a possibly feasible single imaging investigation for the comprehensive diagnosis of coronary stenosis and myocardial ischemia.

Sample Preparation for in vitro Analysis of Iodine in Thyroid Tissue using X-ray Fluorescence

Iodine is enriched and stored in the thyroid gland. Due to several factors, the size of the thyroid iodine pool varies both between individuals and within individuals over time. Excess iodine as well as iodine deficiency may promote thyroid cancer. Therefore, knowledge of iodine content and distribution within thyroid cancer tissue is of interest. X-ray fluorescence analysis (XRF) and secondary ion mass spectrometry (SIMS) are two methods that can be used to assess iodine content in thyroid tissue. With both techniques, choice of sample preparation affects the results. Aldehyde fixatives are required for SIMS analysis while a freezing method might be satisfactory for XRF analysis. The aims of the present study were primarily to evaluate a simple freezing technique for preserving samples for XRF analysis and also to use XRF to evaluate the efficacy of using aldehyde fixatives to prepare samples for SIMS analysis. Ten porcine thyroids were sectioned into four pieces that were either frozen or fixed in formaldehyde, glutaraldehyde, or a modified Karnovsky fixative. The frozen samples were assessed for iodine content with XRF after 1 and 2 months, and the fixed samples were analyzed for iodine content after 1 week. Freezing of untreated tissue yielded no significant iodine loss, whereas fixation with aldehydes yielded an iodine loss of 14–30%, with Karnovsky producing the least loss.

Placental tissue iodine level and blood magnesium concentration in pre-eclamptic and normal pregnancy

Objective To assess iodine concentration in the placental tissue and magnesium concentration in the blood of women with severe pre-eclampsia in northeast Anatolia and compare these values with those of healthy pregnant women from the same region. Methods Placental tissue and blood specimens were obtained from 20 severely pre-eclamptic and 15 healthy pregnant women. Iodine levels in placental tissue were determined by the Foss method based on the Sandell–Kolthoff reaction. Results Placental tissue iodine levels were lower in women with severe pre-eclampsia than in healthy pregnant women (4.30 ± 1.36 ng of iodine/mg protein vs. 7.71 ± 2.84 ng of iodine/mg tissue protein; P < 0.001), as were blood magnesium levels (1.63 ± 0.05 mg/dL vs. 1.87 ± 0.05 mg/dL; P < 0.001). There was a positive correlation between placental tissue iodine levels and blood magnesium levels in women with severe pre-eclampsia ( r = 0.55, P < 0.05), but no such correlation was observed in healthy pregnant women ( r = 0.23, P = 0.41). Conclusion Magnesium assimilation is known to be defective when iodine levels are insufficient. In northeast Anatolia, where iodine deficiency is common, clinical trials of iodine supplementation should be considered for pre-eclamptic therapy.

Long-term effects of high iodine intake: inhibition of thyroid iodine uptake and organification in Wistar rats

To investigate the effects of chronic iodine excess on thyroid function, thyroid peroxidase (TPO) activity, and expression of sodium-iodide symporter (NIS). 500 Wistar rats were randomly exposed to 4 doses of iodine 4 microg/d (G0, control), 6 microg/d (G1), 12 microg/d (G2), and 24 microg/d (G3) for 1, 2, 4 and 8 months. The urine iodine and tissue iodine was determined by arsenic/cerium catalyzing spectrophotograph. Radioimmunoassays were used to detect thyrotropin (TSH), free thyroxin (FT4), free triiodothyronine (FT3), total thyroxin (TT4), and total triiodothyronine (TT3). Guaiacol reaction method and potassium iodide oxygenation method were used to determine the activity of TPO. Suspension of single cells from thyroid tissue was made and the positive rate of NIS was determined by flow cytometry. The expression of NIS protein was assayed by immunohistochemistry. The urine iodine levels of G1, G2, and G3 were 1.5, 3, and 6 times of G0 respectively. FT4, FT3, and total iodine were found progressively accumulated in thyroid tissue with the elevation of iodine intake. The TPO activities of G2 and G3 at the 8th month were 0.17 +/- 0.04 and 0.15 +/- 0.03 respectively, both significantly lower than that of G0 (0.4 +/- 0.23, P < 0.05). The levels of iodine intake at different time points of G1-3 were significantly reduced in a iodine-dose dependent manner (r = -0.63 to -0.78, P < 0.01). The 131I intake at month 8 of G1, G2, and G3 were 56%, 49%, and 39% that of G0 respectively. At month 8 the NIS positive rates of G2 and G3 were significantly lower than that of G0 (both P < 0.05). The NIS protein positive rate was positively correlated with NIS protein expression intensity (r = 0.7-0.72, P < 0.01). The iodine content of thyroid tissue was negatively correlated with TPO activity, iodine intake rate, NIS protein positive rate and expression intensity (r = -0.62 to -0.88, P < 0.05). Moderate iodine excess continuously suppresses the thyroid iodine uptake and organification, which presents a mechanism for iodine-induced thyroid failure.

A preliminary study on tailoring of fillet iodine concentrations in adult Atlantic salmon (Salmo salar L.) through dietary supplementation

The present study was performed to assess to what degree supplemented dietary iodine (I) was retained in selected tissues, including the fillet of adult Atlantic salmon (Salmo salar) reared in sea water. Atlantic salmon weighing approximately 1.5 kg were randomly assigned to three net pens per treatment and fed moist pellets (based on minced saithe and herring) supplemented with 0, 40 or 80 mg iodine (as KI) kg−1 on dry weight basis for 150 days. The iodine concentrations in the experimental feeds were analysed to be 10, 54 and 86 mg kg−1 dry weight, respectively. Growth, mortality and blood haemoglobin concentration (Hb) were recorded. Iodine concentrations were measured in muscle, liver and kidney after 90 and 150 days of feeding by inductively coupled plasma-mass spectrometry. In addition, plasma thyroxine (T4) and triiodo-thyronine (T3) were determined. The weight gain during the period was approximately 1 kg for all treatments. There were no mortalities, and blood Hb levels were within normal ranges. The iodine concentration in muscle, liver and kidney were all affected by the dietary iodine level, despite wide intratreatment variation. After 150 days, fillets of fish fed 10, 54 and 86 mg I kg−1 showed mean concentrations of 0.4, 0.5 and 0.9 mg I kg−1 wet weight, respectively, whereas the iodine concentration in the liver and the kidney increased approximately three times in the dietary groups. Similarly, plasma T4 and T3 showed great variation within the treatments. No significant correlations were found between individual tissue iodine concentration and thyroid hormone concentration in any of the groups at any sampling time. This preliminary feeding experiment showed that fillet iodine in adult Atlantic salmon can be increased up to 1.4 mg I kg−1 wet weight by dietary iodine 80 times the minimum requirement for salmonids, without impacting health, performance or plasma thyroid hormone status.

MEASUREMENT OF TRACE METALS IN THYROID NODULES IN IRAN BY PIXE

A PIXE (Proton Induced X-ray Emission) analysis is applied for measuring the concentration of 21 major and minor trace metal elements (in the range of Z =13-53) for normal, adenoma and carcinoma human thyroid tissues. A 2.0 MeV proton beam was employed to excite the samples. The thyroid samples were obtained from 14 patients during surgical operations, with which normal and damaged parts are concerned as an aid to understand the mechanisms of formation of thyroid cancer and as a complementary diagnostic tool. Thirty samples were measured in total. Fourteen samples of them were in pairs, i.e.14 tumor samples with 14 corresponding healthy tissue specimens taken at a distance from the tumor. The statistical analysis of the results shows the lower levels of the mean value of iron and iodine in the carcinoma tissues than those in the normal tissues; especially iodine is about one tenth of the normal value. On the contrary, the elevation of the mean value for calcium and zinc in the carcinoma tissues in comparison with the normal ones is observed, while in the adenoma tissues copper is very lower than those in the normal thyroid. The concentration of iron in the adenoma is two times of normal tissues.

Comparison of iodine contents in gastric cancer and surrounding normal tissues

It has been suggested that iodine plays an important role in gastric cancer. Gastric cancer ranks first among the cancers in the north-eastern Anatolia region, Turkey, where iodine deficiency is common. In this study, iodine levels were determined in gastric cancer and surrounding normal tissues in 19 patients with gastric cancer. Tissue iodine levels were determined by the Foss method based on the Sandell-Kolt-hoff reaction. Tissue iodine levels were lower in gastric cancer tissue (17.8+/-3.4 ng I/mg protein, mean+/-SEM) compared with surrounding normal tissue (41.7+/-8.0 ng I/mg protein) (p<0.001). There was positive correlation between the iodine levels in gastric cancer tissue and surrounding normal tissue (r = 0.845, p<0.001). There was no significant difference in iodine levels in cancer and surrounding normal tissue between male and female subjects. The iodine deficiency in our region may be one of the factors for increased gastric cancer prevalence. Our results support the hypothesis that iodine plays an important role in gastric cancer development.

Absence of interference of serum IgGs from patients with breast cancer and thyroid autoimmunity on the function of human iodide symporter gene stably transfected in CHO cells

The cause of the association between breast cancer (BC) and thyroid autoimmunity is still unknown. Na+/I- symporter (NIS) is highly expressed in BC cells, and previous studies demonstrated that iodine content in BC is lower than in remote normal breast tissue, suggesting a disorder of iodide uptake in BC. In this study, we evaluated the presence of putative serum autoantibodies able to block the function of NIS in BC patients with thyroid autoimmunity. IgGs were obtained from: a) 11 patients with BC and high antithyroglobulin (TgAb) and antithyroperoxidase (TPOAb) autoantibodies serum concentration; b) 34 patients with Hashimoto's thyroiditis (HT) (1 was euthyroid, 4 had subclinical hypothyroidism and 29 were overtly hypothyroid); c) 15 control subjects. The biological activity of NIS was studied using a chinese hamster ovary (CHO) cell line stably expressing NIS (NIS-CHO). The course of iodide accumulation in NIS-CHO was studied after addition of Na125 I in culture medium. The accumulation of iodide linearly increased between 2 and 10 min, reaching a plateau at 45 min. The preincubation of NIS-CHO with IgGs purified from sera of BC with the highest levels of TPOAb and TgAb caused an inhibition of iodine uptake of no more than 5%. Similar results were obtained using IgGs purified from patients with HT and control subjects. Our data showed no interference of autoantibodies on iodine uptake in patients with BC and thyroid autoimmunity and the very low percentage of inhibition of iodine uptake cannot explain the lower content of iodine in BC tissue.

The effect of dietary arsenic additions on the distribution of selenium and iodine in eggs and tissues of laying hens.

The aim of the work was to determine the short-term effect (19 days) of dietary As additions (30 microg As/g in the form As2O3) on the Se and I concentrations in eggs and tissues of 49-week-old Rhode Island Red laying hens. Se and I concentrations were determined in eggs collected from the 8th to the 10th and from the 17th to the 19th days of the experiment. After 19 days, blood was collected by anterior heart puncture, and after slaughter the liver, kidney, lung, muscle (musculus pectoralis superficialis) and feathers were collected. Se and I concentrations were determined by radiochemical neutron activation analysis and the results expressed on a dry matter basis. In the control and the exposed group, the highest Se concentrations were found in kidney, followed by liver, blood, lung, muscle, and feathers. In the control group the highest I concentration was found in feathers, followed by kidney, blood, lungs, liver, and muscle. In the trial group, the order was almost the same, except that blood concentration was lower than in liver. As2O3 added to the feed significantly increased the Se concentration in the lung (p = 0.0216), I concentration in muscle (p = 0.0112) and significantly decreased I concentration in blood (p = 0.0371). It had no effect on the concentrations of Se and I in egg yolk and white.