Effectiveness of a targeted primary preventive intervention in a high-risk group identified using an efficiency score from data envelopment analysis: a randomised controlled trial of local residents in Japan.

OBJECTIVE: To determine whether a minimal intervention based on the data envelopment analysis (DEA)-identified efficiency score effectively prevents hypertension. DESIGN: Randomised controlled trial. SETTING: Takahata town (Yamagata, Japan). PARTICIPANTS: Residents aged 40-74 years belonged to the information provision group for specific health guidance. Participants with a blood pressure ≥140/90 mm Hg, those taking antihypertensive medication, or those with a history of cardiac diseases were excluded. Participants were consecutively assigned based on their health check-up visit at a single centre from September 2019 to November 2020 and were followed up at the check-up in the following year, until 3 December 2021. INTERVENTION: A targeted approach using minimal intervention. Target was identified using DEA and 50% of participants with higher risk were targeted. The intervention was notifying the results of their risk of hypertension according to the efficiency score obtained by the DEA. PRIMARY OUTCOME MEASURES: A reduction in the proportion of participants who developed hypertension (≥140/90 mm Hg or taking antihypertensive medication). RESULTS: A total of 495 eligible participants were randomised, and follow-up data were available for 218 and 227 participants in the intervention and control groups, respectively. The risk difference for the primary outcome was 0.2% (95% CI -7.3 to 6.9) with 38/218 (17.4%) and 40/227 (17.6%) events in the intervention and control group, respectively (Pearson's χ2 test, p=0.880). The adjusted OR of the effect of the intervention was 0.95 (95% CI 0.56 to 1.61, p=0.843), and that of the efficiency score (10-rank increase) was 0.81 (95% CI 0.74 to 0.89, p<0.0001). CONCLUSIONS: Minimal intervention to a high-risk population stratified by DEA was not effective in reducing the onset of hypertension in 1 year. The efficiency score could predict the risk of hypertension. TRIAL REGISTRATION NUMBER: UMIN000037883.

Melanin-producing medullary thyroid carcinoma with transformation to melanoma: A case report.

Only one case of melanoma arising from melanin-producing medullary thyroid carcinoma (MTC) has been reported previously. In the present study, a second such case was reported and compared with the previous one. The patient was an 86-year-old male who presented with a right anterior neck mass. Ultrasound revealed a nodule measuring 49x48x40 mm in the right lobe of the thyroid. The levels of serum calcitonin (2,298 pg/ml) and carcinoembryonic antigen (CEA; 27.0 ng/ml) were markedly elevated. Aspiration cytology revealed suspected malignant anaplastic thyroid carcinoma and total thyroidectomy without neck nodal dissection was performed. On gross observation, the nodule was well encapsulated, soft, solid and black. Light microscopy indicated that the nodule was composed mainly of large, occasionally huge, pleomorphic cells with a solid or alveolar growth pattern. On immunohistochemistry, these cells were positive for melan-A and S-100 protein, and negative for thyroid transcription factor 1, calcitonin, chromogranin A and CEA. In the subcapsular area, melanin-producing MTC was intimately intermingled with the pleomorphic cells. No primary site of the melanoma was detectable in other organs. At three years after surgery, the patient died due to metastasis of the melanoma to the brain. The previously reported case had no detectable recurrence or distant metastasis up to 11 years after surgery. In comparison with that case, the present case had a similar morphology but the outcome was poorer. Thus, the prognosis of melanoma that transforms from MTC appears to remain uncertain.

Efficacy of Additional Intervention to the Specific Health Guidance in Japan: The Takahata GENKI Project.

PURPOSE: A tailored approach to individual risk factors for developing lifestyle-related diseases would help induce behavioral changes toward intervention acceptability. The addition of preventive healthcare programs to nationwide specific health guidance in Japan is adapted in a given region. PATIENTS AND METHODS: We conducted a prospective parallel-group comparison study on 195 eligible residents from Takahata, Japan, with a high risk of lifestyle-related diseases from 2014 to 2017 to examine whether such an intervention could improve the body mass index (BMI) and estimated glomerular filtration rate (eGFR). RESULTS: Of the 195 enrolled residents, 117 were assigned to the control group and 78 to the intervention group. They were ≤65 years old and had a BMI ≥25 kg/m2 and an eGFR ≤90 mL/kg/1.73 m2. We conducted certain interventions for each group, including additional blood testing, regular health guidance, and specific health guidance. After one year, neither BMI (intervention: 26.7 ± 2.17 kg/m2 vs control: 27.3 ± 2.12 kg/m2, p = 0.076) nor eGFR (intervention: 72.2 ± 11.1 mL/kg/1.73 m2 vs control: 73.1 ± 10.5 mL/kg/1.73 m2, p = 0.608) differed significantly between groups. However, after three years, the BMI in the intervention group (26.4 ± 2.05 kg/m2) was significantly reduced compared to that in the control group (27.4 ± 2.26 kg/m2; p = 0.005). CONCLUSION: The additional interventions might have contributed to a reduction in metabolic syndrome. TRIAL REGISTRATION: This study was registered in the UMIN-Clinical Trials Registry (ID:000013581). More information: https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000015868. The registration date was 31/03/2014.

Influence of Short-Term Dietary and Therapeutic Iodine Restriction on the Therapeutic Effects of Radioactive Iodine Therapy in Patients with Graves' Disease.

Background: Several studies have investigated the factors affecting the effects of radioactive iodine (131I) treatment (RAIT) in patients with Graves' disease. However, the influence of dietary or therapeutic iodine on the effect of RAIT has not been fully elucidated yet. The aim of this study was to investigate whether dietary or therapeutic iodine before RAIT influences the therapeutic effects of RAIT with a fixed-dose regimen and a short-term restriction of iodine intake in an iodine-sufficient area. Materials and Methods: We retrospectively analyzed 81 Japanese patients with Graves' disease treated with the following RAIT regimen: dietary iodine restriction for 7 days as well as discontinuation of antithyroid drugs (ATDs), potassium iodine (KI), or both for 5 days before RAIT. On the day of RAIT, we measured urinary iodine content to estimate daily iodine intake. After RAIT, we adjusted the dose of ATDs, KI, or both according to serum thyroid hormone levels every 1-2 months. Using the data from these patients, we investigated the effect of dietary and therapeutic iodine on the therapeutic effects of RAIT. The therapeutic effects at 1 year after RAIT were evaluated based on the necessity of ATDs, KI, or both. Results: Dietary iodine intake was weakly correlated with 131I uptake (RAIU), but the dose of therapeutic iodine was not correlated with RAIU. The therapeutic effects of RAIT were strongly negatively associated with estimated thyroid volume before RAIT. Neither dietary iodine intake nor therapeutic iodine before RAIT affected this association. Conclusion: This study did not find an association between short-term dietary or therapeutic iodine restriction before RAIT and the therapeutic effects of RAIT in an iodine-sufficient area.

Detection of Circulating Tumor DNA in Plasma: A Potential Biomarker for Esophageal Adenocarcinoma.

BACKGROUND: Recent literature has demonstrated the potential of "liquid biopsy" and detection of circulating tumor (ct)DNA as a cancer biomarker. However, to date there is a lack of data specific to esophageal adenocarcinoma (EAC). This study was conducted to determine how detection and quantification of ctDNA changes with disease burden in patients with EAC and evaluate its potential as a biomarker in this population. METHODS: Blood samples were obtained from patients with stage I to IV EAC. Longitudinal blood samples were collected from a subset of patients. Imaging studies and pathology reports were reviewed to determine disease course. Tumor samples were sequenced to identify mutations. Mutations in plasma DNA were detected using custom, barcoded, patient-specific sequencing libraries. Mutations in plasma were quantified, and associations with disease stage and response to therapy were explored. RESULTS: Plasma samples from a final cohort of 38 patients were evaluated. Baseline plasma samples were ctDNA positive for 18 patients (47%) overall, with tumor allele frequencies ranging from 0.05% to 5.30%. Detection frequency of ctDNA and quantity of ctDNA increased with stage. Data from longitudinal samples indicate that ctDNA levels correlate with and precede evidence of response to therapy or recurrence. CONCLUSIONS: ctDNA can be detected in plasma of EAC patients and correlates with disease burden. Detection of ctDNA in early-stage EAC is challenging and may limit diagnostic applications. However, our data demonstrate the potential of ctDNA as a dynamic biomarker to monitor treatment response and disease recurrence in patients with EAC.

Multilaboratory Assessment of a New Reference Material for Quality Assurance of Cell-Free Tumor DNA Measurements.

We conducted a multilaboratory assessment to determine the suitability of a new commercially available reference material with 40 cancer variants in a background of wild-type DNA at four different variant allele frequencies (VAFs): 2%, 0.50%, 0.125%, and 0%. The variants include single nucleotides, insertions, deletions, and two structural variations selected for their clinical importance and to challenge the performance of next-generation sequencing (NGS) methods. Fragmented DNA was formulated to simulate the size distribution of circulating wild-type and tumor DNA in a synthetic plasma matrix. DNA was extracted from these samples and characterized with different methods and multiple laboratories. The various extraction methods had differences in yield, perhaps because of differences in chemistry. Digital PCR assays were used to measure VAFs to compare results from different NGS methods. Comparable VAFs were observed across the different NGS methods. This multilaboratory assessment demonstrates that the new reference material is an appropriate tool to determine the analytical parameters of different measurement methods and to ensure their quality assurance.

Impact of Polymerase Fidelity on Background Error Rates in Next-Generation Sequencing with Unique Molecular Identifiers/Barcodes.

Liquid biopsy and detection of tumor-associated mutations in cell-free circulating DNA often requires the ability to identify single nucleotide variants at allele frequencies below 0.1%. Standard sequencing protocols cannot achieve this level of sensitivity due to background noise from DNA damage and polymerase induced errors. Addition of unique molecular identifiers allows identification and removal of errors responsible for this background noise. Theoretically, high fidelity enzymes will also reduce error rates in barcoded NGS but this has not been thoroughly explored. We evaluated the impact of polymerase fidelity on the magnitude of error reduction at different steps of barcoded NGS library construction. We find that barcoding itself displays largest impact on error reduction, even with low fidelity polymerases. Use of high fidelity polymerases in the barcoding step of library construction further suppresses error in barcoded NGS, and allows detection of variant alleles below 0.1% allele frequency. However, the improvement in error correction is modest and is not directly proportional to polymerase fidelity. Depending on the specific application, other polymerase characteristics such as multiplexing capacity, PCR efficiency, buffer requirements and ability to amplify targets with high GC content may outweigh the relatively small additional decrease in error afforded by ultra-high fidelity polymerases.

Plasma circulating tumor DNA as a potential tool for disease monitoring in head and neck cancer.

BACKGROUND: Recommendations for perioperative therapy in head and neck cancer are not explicit and recurrence occurs frequently. Circulating tumor DNA is an emerging cancer biomarker, but has not been extensively explored for detection of recurrence in head and neck cancer. METHODS: Patients diagnosed with head and neck squamous cell carcinoma were recruited into the study protocol. Tumors were sequenced to identify patient-specific mutations. Mutations were then identified in plasma circulating tumor DNA from pre-treatment blood samples and longitudinally during standard follow-up. Circulating tumor DNA status during follow-up was correlated to disease recurrence. RESULTS: Samples were taken from eight patients. Tumor mutations were verified in seven patients. Baseline circulating tumor DNA was positive in six patients. Recurrence occurred in four patients, two of whom had detectable circulating tumor DNA prior to recurrence. CONCLUSION: Circulating tumor DNA is a potential tool for disease and recurrence monitoring following curative therapy in head and neck cancer, allowing for better prognostication, and/or modification of treatment strategies.

miRNA profiling of primary lung and head and neck squamous cell carcinomas: Addressing a diagnostic dilemma.

OBJECTIVE: To determine whether microRNA (miRNA) profiling of primary lung and head and neck squamous cell carcinomas could be useful to identify a specific miRNA signature that can be used to further discriminate between primary lung squamous carcinomas and metastatic lesions in patients with a history of head and neck squamous cell cancer. METHODS: Specimens of resected primary head and neck and lung squamous cell carcinomas were obtained from formalin-fixed, paraffin-embedded blocks. Paraffin blocks were sectioned and deparaffinized, and total RNA was isolated and profiled. Quantitative polymerase chain reaction was performed to verify array results. RESULTS: Twelve head and neck and 16 lung squamous cell carcinoma samples met quality control metrics and were included for analysis. Forty-eight miRNAs were differentially expressed (P < .05) between the 2 groups. Of these, 30 were also significantly associated (q < .25) with tumor type in 2 independent sets of primary head and neck and lung squamous carcinomas profiled by The Cancer Genome Atlas consortium, including miR-34a and miR-10a. The ratio of miR-10a and miR-10b was especially predictive of primary cancer site in all 3 data sets, with area under the (receiver operating characteristics) curve values ranging from 0.922 to 0.982. Quantitative polymerase chain reaction confirmed the association of miR-34a expression and the miR-10:miR-10b ratio with tumor type. CONCLUSIONS: MicroRNA expression may be useful for discriminating between head and neck and lung squamous cell carcinomas, including miR-34a and the miR-10a:miR-10b ratio. This differentiation has clinical importance because it could help determine the appropriate therapeutic approach.

Cutoff value of thyroid uptake of (99m)Tc-pertechnetate to discriminate between Graves' disease and painless thyroiditis: a single center retrospective study.

Thyroid uptake of (99m)Tc-pertechnetate is a useful way to determine the cause of thyrotoxicosis. In daily clinical practice, (99m)Tc-pertechnetate uptake is used to discriminate between Graves' disease and painless thyroiditis when clinical information is not enough to make the distinction. However, since the optimal cutoff value of (99m)Tc-pertechnetate uptake has not yet been elucidated, our aim was to determine this value. We recruited patients with thyrotoxicosis in whom (99m)Tc-pertechnetate uptake was measured in clinical settings between 2009 and 2013. Three experienced endocrinologists (who were blinded to the value of (99m)Tc-pertechnetate uptake and initial treatment) diagnosed the cause of thyrotoxicosis based on thyrotropin, free triiodothyronine, free thyroxine, and thyrotropin receptor antibody levels, and by ultrasound findings and using images of thyroid uptake of (99m)Tc-pertechnetate without the actual values. Ninety-four patients diagnosed as having Graves' disease or painless thyroiditis were finally included. According to the diagnosis, the optimal cutoff value of (99m)Tc-pertechnetate uptake was determined by receiver operating characteristics analysis. A cutoff value of 1.0% provided optimal sensitivity and specificity of 96.6% and 97.1%, respectively. Then, its validity was confirmed in 78 patients with confirmed Graves' disease or painless thyroiditis diagnosed at another institute. Applying this cutoff value to the patients with thyrotoxicosis revealed positive and negative predictive values for Graves' disease of 100% and 88.9%, respectively. In conclusion, a cutoff value for (99m)Tc-pertechnetate uptake of 1.0% was useful to discriminate between Graves' disease and painless thyroiditis.

Telomere shortening in breast cancer correlates with the pathological features of tumor progression.

Telomeres are involved in the maintenance of genomic stability. Telomere alteration has been observed in most human cancer types, and is known to be a feature of malignancy. The aim of the present study was to evaluate whether the telomere length of breast cancer cells correlates with TNM stage and several pathological features. We investigated a total of 44 breast cancers, including 17 scirrhous, 15 papillotubular and 12 solid-tubular carcinomas. Telomere lengths were determined by tissue quantitative fluorescence in situ hybridization (Q-FISH), and compared according to the TNM stage, histological tumor size, lymph node metastases, vascular invasion and immunohistochemical status (ER, PR, HER2 status and Ki67 labeling index). In all histological types, telomeres of cancer cells were significantly shorter than those of normal epithelial cells. Mean telomere length was significantly less in patients with TNM stage III, and in those with large tumors, lymph node metastases and vascular invasion. Our results suggest that the telomere length of cancer cells is strongly correlated with the degree of cancer progression.

Thyroglobulin suppresses thyroid-specific gene expression in cultures of normal but not neoplastic human thyroid follicular cells.

CONTEXT: It was shown in the rat thyroid that thyroglobulin (Tg) stored in the follicular lumen is a potent regulator of thyroid-specific gene expression to maintain the function of individual follicles. However, the actions of Tg as a regulatory molecule in human thyroid have not been studied. OBJECTIVE: Our objective was to determine the effect of Tg on gene expression in normal and diseased human thyroid and to examine whether the proposed model of negative-feedback autocrine regulation of thyroid function by Tg is applicable in the human as well as the rat. DESIGN: Primary cultures of human thyrocytes were established from normal thyroid, Graves' disease thyroid, adenomatous goiter, follicular adenoma, and papillary carcinoma tissues obtained during surgery. Cells were stimulated with physiologic (ie, follicular) concentrations of Tg, and mRNA and protein expression of genes involved in thyroid hormonogenesis were evaluated. The effects of Tg on thyroid-specific gene expression were also assessed in 2 human papillary carcinoma cell lines. RESULTS: Transcript levels of genes participating in thyroid hormone biosynthesis were significantly reduced by Tg in thyrocyte cultures derived from normal and Graves' thyroid, but not in cultures derived from thyroid neoplasms and adenomatous goiter. CONCLUSION: It was confirmed that Tg acts as a negative-feedback regulator of gene expression in human thyrocytes, suggesting that Tg signaling may constitute a common mechanism for maintaining thyroid homeostasis in species with follicular thyroid morphology. However, certain diseases of intrinsic thyroid overgrowth appear to be associated with an escape from the regulatory mechanism of Tg.

Amplification of the human epidermal growth factor receptor 2 gene in differentiated thyroid cancer correlates with telomere shortening.

The human epidermal growth factor receptor 2 (HER2) proto-oncogene plays an important role in the development and progression of breast and gastric cancer. Monitoring of the HER2 status and treatment with trastuzumab was performed initially in breast cancer, and subsequently in gastric cancer. However, the HER2 status of thyroid cancer remains unexplored. Telomere alteration and telomerase activity have been observed in most human cancers and are known to be a feature of malignancy. The aims of this study were to clarify the HER2 status of thyroid cancer and to examine any correlations to various characteristics of malignancy. We investigated 69 cases of differentiated thyroid cancers with reference to: i) telomere length as measured using tissue quantitative fluorescence in situ hybridization (Q-FISH), ii) expression of human telomerase reverse transcriptase (hTERT) as determined by immunohistochemistry (IHC), and iii) overexpression of the HER2 protein as determined by IHC and amplification of the HER2 gene as determined by fluorescence in situ hybridization (FISH). The telomeres of thyroid cancers, especially follicular carcinomas, were significantly shorter compared to those of adjacent normal tissues. Positivity for hTERT expression and HER2 amplification were observed in approximately 70 and 22% of thyroid cancers, respectively. Our data demonstrated that telomeres in HER2-positive cancers were significantly shorter compared to those in HER2-negative cancers. These results suggest that highly malignant differentiated thyroid cancer can be detected by monitoring HER2 status and telomere shortening, and that trastuzumab therapy may be effective for refractory thyroid cancer.

Internal structure of a disease name and its application for ICD coding.

ICD-coding is a complex and difficult task. Coding results vary a great deal depending on each coder's ability. Although the Japanese Standard Disease-Code Master facilitates the coding tasks, it also engenders post-coordination problems derived from combinations of basic diseases (with ICD code) and modifiers. Post-coordination sometimes alters the original ICD code dramatically. To solve this problem, this paper presents a proposal for using internal structures of disease names to correct the ICD code. First, we built an internal structure analyzer, which achieved high (83.7%) accuracy. Results demonstrated that the analyzed output is helpful for precise ICD-coding tasks.

Utilization of three-dimensional computed tomography for papillary thyroid carcinoma arising in the thyroglossal duct remnant: report of a case.

This report presents a rare and interesting case of papillary thyroid carcinoma arising in a thyroglossal duct remnant (TDR) that was diagnosed by three-dimensional computed tomography (3DCT). The patient, a 61-year-old woman, presented with a painless mass in the anterior suprahyoid region that had gradually enlarged over a 2-year period. Three-dimensional CT successfully revealed the thyroglossal duct (TD) descending from the tumor to the isthmus of the thyroid. An ultrasonography-guided fine-needle aspiration biopsy of the tumor was positive for carcinoma. A total thyroidectomy was performed in addition to the Sistrunk procedure. The histological findings indicated papillary thyroid carcinoma arising in the TDR and thyroid papillary microcarcinoma in the left thyroid lobe. The patient underwent radioactive iodine ablation and thyroid suppression therapy. This is apparently the first reported case of papillary thyroid carcinoma arising in a TDR evaluated using 3DCT. Three-dimensional CT was able to clarify the relative locations of the tumor, TD, and thyroid in the present case, and visualization of the TD allowed a definitive preoperative diagnosis that would not otherwise have been possible using conventional imaging techniques. This case suggests that 3DCT may therefore play an important role in providing definitive information on patients with anterior neck masses that are difficult to diagnose.

Iodide-induced chemokines and genes related to immunological function in cultured human thyroid follicles in the presence of thyrotropin.

BACKGROUND: It is well known that iodide exacerbates thyroid function in subclinical hypothyroid patients with autoimmune thyroiditis. To investigate the immunological mechanism of iodine-induced thyroid dysfunction, we studied the effect of iodide in cultured human thyroid follicles, which respond to physiological concentrations of human thyrotropin (TSH) (0.3-10 microU/mL) and maintain the Wolff-Chaikoff effect. MATERIALS AND METHODS: Thyroid follicles obtained from Graves' patients at subtotal thyroidectomy were precultured in medium containing 0.5% fetal calf serum and 10(-8) M iodide for 5 days, and then cultured with the medium containing bovine TSH (30 microU/mL) and low (10(-8)M) or high (10(-5)M) concentrations of iodide. After 3-72 hours of culture, the effect of iodide on thyroid cell mRNA expression was analyzed by microarray and reverse transcriptase-polymerase chain reaction. RESULTS: After 48 hours of culture, iodide nearly doubled the mRNA expression levels of the immunity-associated genes (intercellular adhesion molecule-1, transforming growth factor beta 1-induced protein, early growth response gene 1, guanylate-binding protein 1, and annexin A1) and decreased the mRNA expression of sodium-iodide symporter to less than 20%. Further, the mRNA expression levels of chemokines (CCL2, CXCL8, and CXCL14) increased nearly twofold, whereas their receptors did not show any significant response. Real-time polymerase chain reaction analyses confirmed that iodide increased the mRNA expression levels of these genes in a time- and concentration-dependent manner. Immunohistochemical studies revealed that the chemokines were expressed mainly in the thyroid follicular cells in addition to the immune cells. The iodide-induced increase in CCL2 was greater in thyroid follicles obtained from thyroid gland that had been moderately infiltrated with the immunocompetent cells. CONCLUSION: We have demonstrated that iodide stimulates thyroid follicular cells to produce chemokines, particularly CCL2, CXCL8, and CXCL14. These chemokines and intercellular adhesion molecule-1 would attract immunocompetent cells into thyroid gland. These in vitro findings suggest that iodide at high concentrations may induce thyroid dysfunction through not only biochemical but also immunological mechanisms, particularly in patients with autoimmune thyroid disorders.

Follicular carcinoma arising from the pyramidal lobe of the thyroid.

We present a rare case of follicular carcinoma arising from the pyramidal lobe of the thyroid in a 21-year-old woman. Radical resection of the thyroid isthmus was performed, followed by adjuvant hormonal therapy with levothyroxine. After 15 months of follow-up, the patient remains disease-free. Thyroid carcinoma in children and adolescents is rare, and also rarely arises in the pyramidal lobe. To our knowledge, this is the first report of this type of neoplasm arising from the thyroid pyramidal lobe. We are following up this case carefully, and if recurrence or metastasis or both occur, we plan to perform total thyroidectomy and ablation with (131)I. This case suggests the importance of the differential diagnosis of midline cervical masses and the management of this type of neoplasm in adolescents.

Differential diagnosis and appropriate treatment of four thyrotoxic patients with Graves' disease required to take amiodarone due to life-threatening arrhythmia.

We report the treatment of four thyrotoxic patients. Two were cases of type I amiodarone-induced thyrotoxicosis (AIT) treated with methimazole. The third Graves' disease patient, who became hypothyroid 25 years after subtotal thyroidectomy, developed type II AIT. Furthermore, one case with heart failure and ventricular tachycardia, who developed an adverse reaction to antithyroid agents and was prescribed amiodarone, underwent total thyroidectomy. The clinical course was uneventful, and the patient is doing well. Since amiodarone contains a large amount of iodine, it is frequently difficult to make a differential diagnosis. Surgical treatment of Graves' disease patients is recommended when immediate control of hyperthyroidism and heart failure is required.

Amiodarone reversibly decreases sodium-iodide symporter mRNA expression at therapeutic concentrations and induces antioxidant responses at supraphysiological concentrations in cultured human thyroid follicles.

CONTEXT: Amiodarone, a potent antiarrhythmic, iodine-containing agent, is a highly active oxidant exerting cytotoxic effects on thyrocytes at pharmacological concentrations. Patients receiving amiodarone usually remain euthyroid, but occasionally develop thyroid dysfunction. Although there is a general consensus that amiodarone-associated hypothyroidism is iodine induced, the destructive mechanism of thyroid follicles in amiodarone-induced thyrotoxicosis remains unknown. OBJECTIVE: To elucidate the mechanism by which amiodarone elicits thyroid dysfunction. DESIGN: Human thyroid follicles were cultured with thyroid-stimulating hormone (TSH) and amiodarone at therapeutic (1-2 microM) and pharmacological (10-20 microM) concentrations, and the drug-induced effect on whole human gene expression was analyzed by cDNA microarray. Microarray data were confirmed by real-time PCR and Western blot. MAIN OUTCOMES: Amiodarone at 1-2 muM decreased the expression level of the sodium-iodide symporter (NIS) to nearly half, but did not affect genes participating in thyroid hormonogenesis (thyroid peroxidase, thyroglobulin, pendrin, and NADPH oxidase). Higher concentrations (10-20 microM) decreased the expression of all these genes, accompanied by increased expression of antioxidant proteins such as heme oxygenase 1 and ferritin. When thyroid follicles obtained from a patient with Graves' disease who had been treated with amiodarone were cultured in amiodarone-free medium, TSH-induced thyroid function was intact, suggesting that amiodarone at a maintenance dose did not elicit any cytotoxic effect on thyrocytes. The ultrastructural features of cultured thyroid follicles were compatible with these in vitro findings. CONCLUSION: These in vitro and ex vivo findings suggest that patients taking maintenance doses of amiodarone usually remain euthyroid, probably due to escape from the Wolff-Chaikoff effect mediated by decreased expression of NIS mRNA. Further, amiodarone is not cytotoxic for thyrocytes at therapeutic concentrations but elicits cytotoxicity through oxidant activity at supraphysiological concentrations. We speculate that when amiodarone-induced prooxidant activity somehow exceeds the endogenous antioxidant capacity, the thyroid follicles will be destroyed and amiodarone-induced destructive thyrotoxicosis may develop.

Povidone iodine-induced overt hypothyroidism in a patient with prolonged habitual gargling: urinary excretion of iodine after gargling in normal subjects.

Iodine-induced hypothyroidism that develops in patients who gargle routinely with povidone iodine is well known. Usually the hypothyroidism is mild and resolves spontaneously upon cessation of gargling. Here, we report a 63-year-old patient with overt hypothyroidism that developed due to habitual gargling with povidone iodine for more than 10 years. The urinary excretion of iodine was estimated to be greater than 5 mg/day, based on values obtained from 18 normal subjects who gargled three times a day (4.6+/-2.1 mg, mean+/-SD). After discontinuation of the gargling, the patient has been euthyroid for more than 10 months.