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Abstract We studied the mechanism that may explain the relative resistance of thyrocytes to H 2 O 2 compared to other cell types. Ability to degrade H 2 O 2 , glutathione peroxidase (GPx) activity, heme oxygenase-1 (HO-1) expression, cell survival and capacity to repair DNA damage after H 2 O 2 exposure or irradiation were measured in human thyrocytes in primary culture and compared to the values obtained in human T-cells and different cell lines. Compared to other cell types, thyrocytes presented a low mortality rate after H 2 O 2 exposure, rapidly degraded extracellular H 2 O 2 and presented a high basal seleno-dependent GPx activity. Only in thyrocytes, H 2 O 2 up-regulated GPx activity and expression of HO-1 mRNA. These effects were not reproduced by irradiation. DNA damage caused by H 2 O 2 was more slowly repaired than that caused by irradiation and not repaired at all in T-cells. Our study demonstrates that the thyrocyte has specific protective mechanisms against H 2 O 2 and its mutagenic effects. Highlights • Resistance of the tested cell types against irradiation was relatively equal. • Resistance against H 2 O 2 was largely dependent on the cell type, T-cells being the more fragile. • Thyrocyte is well protected against H 2 O 2 and oxidative stress by several defense mechanisms. • In thyrocyte exposure to H 2 O 2 leads to upregulation of antioxidant genes. • Disability of these protective mechanisms could be responsible for the appearance of mutations leading to thyroid cancer. [ABSTRACT FROM AUTHOR]

Objective The effects of endogenous subclinical hyperthyroidism ( eSCH) on heart and bone have been well documented. There are only limited data available regarding the impact of eSCH on weight regulation and lipid metabolism. Our aim was to evaluate the changes in body weight and metabolic parameters after total thyroidectomy in patients with pre-operative eSCH compared with pre-operative patients with euthyroid (EUT). Design A retrospective study of 505 patients who underwent total thyroidectomy for benign multinodular goitre in an academic hospital in Brussels (Belgium) was performed. Patient's Measurements Two hundred and 25 patients were included ( eSCH group: n = 74; EUT group: n = 151). The mean follow-up time was 26·1 ± 0·8 months and was similar in both groups. Results Absolute BMI gain was significantly greater in the eSCH group than in the EUT group (1·11 ± 0·17 vs 0·33 ± 0·13 kg/m2; P = 0·003). A significant increase in LDL cholesterol was observed in the eSCH group (16·1 ± 3·8 mg/dl; P < 0·001 ) but not in the EUT group (0·0 ± 3·0 mg/dl; P = 0·88). In a multivariate model, pre-operative TSH levels were the main factor significantly associated with increases in BMI or LDL cholesterol. Post-operative median TSH levels and L-thyroxine substitution were similar in both groups. Conclusion After total thyroidectomy, increases in weight and serum cholesterol were observed in the eSCH group. Given that post-operative TSH levels were similar in the two groups, these observations are probably due to the correction of eSCH, suggesting a direct effect of eSCH on body weight regulation and lipid metabolism. [ABSTRACT FROM AUTHOR]

Objective The use of thyroid lobectomy in the treatment of unilateral, benign nodules is limited by the potential of nodular recurrence in the remaining lobe. This study aimed to assess the rate and clinical impact of nodular recurrence in the contralateral lobe after thyroid lobectomy and to identify predictive factors of recurrence. Design Single-centre retrospective study. Patients Records of patients that underwent lobectomy for unilateral thyroid nodules between 1991 and 2010 were reviewed and 270 patients were included. Exclusion criteria were: presence of contralateral nodule(s) ≥5 mm on preoperative ultrasound, diagnosis of cancer necessitating completion thyroidectomy or pseudonodules. Recurrence was defined as the occurrence of nodule(s) ≥5 mm in the remaining lobe on at least one postoperative ultrasound. A set of clinical, imaging, histological and biochemical parameters was tested as predictors of recurrence using logistic regression. Results After a median follow-up of 78 months (range, 12-277 months), the global recurrence rate was 42% and recurrence of nodules of a size ≥1 cm occurred in 19%. Reoperation rate was 1·1%. 90% of patients were treated postoperatively by levothyroxine. Median time to nodular recurrence was 4 years. Preoperative contralateral lobe volume and resected thyroid weight were identified as significant predictors of recurrence ( P = 0·045 and P = 0·03 respectively). Conclusions Thyroid lobectomy is an effective therapeutic strategy for unilateral, benign nodules, resulting in a low rate of clinically relevant nodular relapse in a mildly iodine-deficient area. Patients with uninodular disease and a contralateral lobe of normal size are particularly good candidates for lobectomy. [ABSTRACT FROM AUTHOR]

The letter published in the Clinical Chemistry & Laboratory Medicine journal highlights the urgent need to adopt age-specific upper reference limits for thyroid-stimulating hormone (TSH) in the elderly. As individuals age, TSH levels tend to increase, leading to potential misdiagnoses of subclinical hypothyroidism and unnecessary treatment with levothyroxine. The European Thyroid Association and the United States National Academy of Clinical Biochemistry recommend age-specific TSH reference ranges to accurately diagnose and manage thyroid disorders in older individuals. It is crucial for clinicians to consider age-related changes in TSH levels, comorbidities, and other influencing factors when deciding on interventions for elevated TSH levels in the elderly. [Extracted from the article]

The article, titled "Use of thyroid function tests in urine: a position statement of the Belgian Thyroid Club," discusses the use of urine testing for thyroid hormones and argues against its reliability and usefulness in diagnosing and managing thyroid disorders. The authors highlight limitations such as lack of sensitivity and specificity, susceptibility to interference, and lack of standardized assays and reference ranges. They emphasize that blood testing for thyroid hormones is the only evidence-based method recommended by international scientific societies for the diagnosis and management of thyroid diseases. [Extracted from the article]