Clinical performance of the Roche cobas e411 automated assay system for thyrotropin-receptor antibodies for the diagnosis of Graves' disease.

BACKGROUND: The clinical performance of the Roche cobas e411 automated assay for the measurement of thyrotropin (TSH)-receptor antibodies (TRAbs) for the diagnosis of Graves' disease was evaluated in the setting of new referrals to a specialized thyroid clinic. METHODS: The final diagnosis of 102 new patients attending their first outpatient appointment at a thyroid clinic was correlated with the TRAbs result. In all cases, the diagnosis was made independently of the TRAbs result by the same consultant (ADT) based on clinical examination, thyroid function tests (TSH, free thyroxine, total triiodothyronine measured on Architect; Abbot Diagnostics), and a technetium-99m uptake and scan. TRAbs were measured using the cobas e411 (Roche Diagnostics). The clinical sensitivity and specificity of the assay were determined and compared with other published performance characteristics of the assay. RESULTS: Optimal sensitivity (95%) and specificity (98%) were obtained using a cut-off of 1.6 IU/L. The positive and negative predictive values at this cut-off were calculated as 98% and 94%, respectively. CONCLUSIONS: Using a cut-off of 1.6 IU/L, considered independently of thyroid function tests, the Roche cobas e411 automated immunoassay for TRAbs is a convenient, sensitive and specific tool for the differential diagnosis of hyperthyroidism.

Differential effects of doses and forms of dietary selenium on immune cell numbers in the skin of ultraviolet-irradiated and unirradiated mice.

The effect of three different doses of dietary L-selenomethionine (SM) and sodium selenite (SS) on skin selenium (Se) content, glutathione peroxidase (GPx) activity, Langerhans cell (LC) and mast cell numbers in ultraviolet radiation-B (UVB)-irradiated and unirradiated C3H/HeN mice was determined. After weaning, groups of mice were given Se-deficient, Se-adequate, or Se-high diets. Six weeks later, some animals in each group were exposed to a single UVB dose (acute), while others were exposed three times weekly for the following 40 weeks (chronic). The skin Se content and GPx activity increased in all the Se-supplemented groups, and the latter was not altered by UVB exposure. Generally, the Se-containing diets caused an increase in LC numbers at 6 weeks and a further rise at 40 weeks, but did not prevent the loss induced by acute or chronic UVB radiation. Skin mast cell numbers were highest in animals fed the Se-deficient diet after 6 and 40 weeks. Acute and chronic UVB radiation decreased the mast cell number and dietary Se did not prevent the reduction. While the present study shows that Se plays an important role in governing the number of LCs and mast cells in the skin, no protective effect against the immunomodulating properties of UVB radiation on these cell types was observed. However, this conclusion may only apply to the experimental conditions chosen, and additional studies at different Se dosages and reduced intensities of chronic UVB exposure are required to confirm the results.

Mechanisms of selenium-mediated protection from photocarcinogenesis and cell death are not solely p53-dependent.

Recent studies published in Oncogene and Proc. Natl. Acad. Sci. USA ascribe a role for selenium, acting through wild type p53, in protecting skin cells in culture from ultraviolet radiation-induced death. While selenium clearly protects cells against ultraviolet radiation-induced death, data that we present and discuss in this letter shows that wild type p53 is not required for such protection. Moreover the non-physiologically high levels of selenium used in some studies leads us to question the relevance of such effects for selenium-induced photoprotection.

Endocrine measurements in survivors and non-survivors from critical illness.

OBJECTIVE: To compare measurements of thyroid and adrenal function between survivors and non-survivors in critical illness. DESIGN AND SETTING: Prospective, observational study at the medical/surgical intensive care unit (ICU) at Royal Infirmary of Edinburgh, Scotland. PATIENTS: 163 patients admitted to the intensive care unit over a 4-month period. INTERVENTIONS: We took blood samples within 1 h of ICU admission, and at 08:00 hours on the subsequent 2 days of ICU admission. We measured serum total (TT(4)) and free (fT(4)) thyroxine, total (TT(3)) and free (fT(3)) tri-iodothyronine, thyrotropin (TSH) and plasma cortisol concentrations. MEASUREMENTS AND RESULTS: TT(3) and TT(4) concentrations were significantly less in non-survivors than in survivors on admission and on day 1 but not on day 2. Cortisol concentrations were higher in non-survivors on admission and on day 1 but not on day 2. TSH, fT(3) and fT(4) concentrations did not differ significantly between survivors and non-survivors at any time. Only TT(4) and cortisol were independent predictors of outcome. Prediction of outcome from the admission sample values was not better than using APACHE II scoring. CONCLUSIONS: Thyroid hormone and cortisol concentrations differ between survivors and non-survivors on admission to intensive care, but the values overlap. These differences do not allow accurate prediction of outcome from critical illness.