The TRH test provides valuable information in the diagnosis of central hypothyroidism in patients with known pituitary disease and low T4 levels.

Objective: To evaluate the value of the thyrotropin-releasing hormone (TRH) test in the diagnosis of central hypothyroidism (CH) in patients with pituitary disease. Methods: Systematic evaluation of 359 TRH tests in patients with pituitary disease including measurements of thyroxine (T4), TBG-corrected T4 (T4corr), baseline TSH (TSH0) and relative or absolute TSH increase (TSHfold, TSHabsolute). Results: Patients diagnosed with CH (n=39) show comparable TSH0 (p-value 0.824) but lower T4corr (p-value <0.001) and lower TSH increase (p-value <0.001) compared to patients without CH. In 54% (42 of 78 cases) of patients with low T4corr, the CH diagnosis was rejected based on a high TSHfold. In these cases, a spontaneous increase and mean normalization in T4corr (from 62 to 73 nmol/L, p-value <0.001) was observed during the follow-up period (7.6 ± 5.0 years). Three of the 42 patients (7%) were started on replacement therapy due to spontaneous deterioration of thyroid function after 2.8 years. Patients diagnosed with CH reported significantly more symptoms of hypothyroidism (p-value 0.005), although, symptoms were reported in most patients with pituitary disease. The TRH test did not provide clinical relevant information in patients with normal T4 or patients awaiting pituitary surgery (78%, 281 of 359). There were only mild and reversible adverse effects related to the TRH test except for possibly one case (0.3%) experiencing a pituitary apoplexy. Conclusion: The TRH test could be reserved to patients with pituitary disease, low T4 levels without convincing signs of CH. Approximately 50% of patients with a slightly decreased T4 were considered to have normal pituitary thyroid function based on the TRH test results.

Machine learning to improve false-positive results in the Dutch newborn screening for congenital hypothyroidism.

OBJECTIVE: The Dutch Congenital hypothyroidism (CH) Newborn Screening (NBS) algorithm for thyroidal and central congenital hypothyroidism (CH-T and CH-C, respectively) is primarily based on determination of thyroxine (T4) concentrations in dried blood spots, followed by thyroid-stimulating hormone (TSH) and thyroxine-binding globulin (TBG) measurements enabling detection of both CH-T and CH-C, with a positive predictive value (PPV) of 21%. A calculated T4/TBG ratio serves as an indirect measure for free T4. The aim of this study is to investigate whether machine learning techniques can help to improve the PPV of the algorithm without missing the positive cases that should have been detected with the current algorithm. DESIGN & METHODS: NBS data and parameters of CH patients and false-positive referrals in the period 2007-2017 and of a healthy reference population were included in the study. A random forest model was trained and tested using a stratified split and improved using synthetic minority oversampling technique (SMOTE). NBS data of 4668 newborns were included, containing 458 CH-T and 82 CH-C patients, 2332 false-positive referrals and 1670 healthy newborns. RESULTS: Variables determining identification of CH were (in order of importance) TSH, T4/TBG ratio, gestational age, TBG, T4 and age at NBS sampling. In a Receiver-Operating Characteristic (ROC) analysis on the test set, current sensitivity could be maintained, while increasing the PPV to 26%. CONCLUSIONS: Machine learning techniques have the potential to improve the PPV of the Dutch CH NBS. However, improved detection of currently missed cases is only possible with new, better predictors of especially CH-C and a better registration and inclusion of these cases in future models.

Effect of Radioimmunoassay on Accuracy of Thyroid Hormone Detection.

At present, the most important method for the detection of thyroid hormones in hospitals in China is radioimmunoassay. Besides radioimmunoassay, there are blood test and antibody test methods for thyroid hormone detection. However, after long-term clinical investigations, the accuracy of the results of thyroid hormone detection by radioimmunoassay has been affected by many factors. Possible influencing factors include inaccurate thyroid hormone test results due to improper way of blood collection by nurses and improper way of keeping and transporting blood samples by nurses. Therefore, this paper analyzes and discusses the influencing factors of the accuracy of thyroid hormone (T4) detection by radioimmunoassay technology. In this paper, we conducted research using statistical analysis of clinical data, improved separation methods for quality control in the laboratory, and blood specimen collection methods. Radioimmunoassay occurs with antibodies. Of the 10 batches of 964 cases in the improved separation methods for quality control in the laboratory, 154 mismatched items accounted for 16%, and the error of method and operation only accounted for 5.8% of unmatched specimens, most of which were the biochemical characteristics and clinical manifestations of thyroid hormones. The blood sample collection method research found that mild hemolysis had no significant effect on the measurement results, severe hemolysis had a tendency to affect the results, and blood collection tubes had no effect on the test results. Mild hemolysis refers to the increase in the rate of red blood cell destruction due to various internal and external factors in the body. The symptoms when mild hemolysis occurs are generally not obvious. Severe hemolysis refers to a disease caused by blood group incompatibility, mainly referring to immune hemolysis caused by blood group incompatibility between mother and baby, as well as severe jaundice or severe anemia. The statistical analysis of clinical data found that, among 160 patients, the reasons for the inaccuracy of T4 results using radioimmunoassay technology were as follows: 104 patients were inaccurate due to personal factors, and the results were due to hospital factors. A total of 56 patients had inaccurate results. During the measurement of thyroid hormone, it will be affected by many factors. For this reason, the influencing factors of the accuracy of radioimmunoassay should be clarified, and appropriate measures should be taken to deal with it, so as to give full play to the role of radioimmunoassay and improve the detection.

Effects of lead exposure on biomarkers of thyroid and renal function tests among panel beaters in Enugu Metropolis, Nigeria.

Background: Occupational lead (Pb) exposure causes multisystem effects at high and sustained low doses. However, there are inconsistencies in the dose-response effects on the thyroid and kidneys. Aim: This study aimed to assess the effects of Pb exposure on the biomarkers of thyroid and renal functions among panel beaters in Enugu Metropolis, Nigeria. Subjects and Methods: This was a cross-sectional analytical study of 428-panel beaters selected using a multistage sampling technique. Blood lead (BPb), thyroid, and kidney biomarkers were analyzed using atomic absorption spectrometer at 238.3 nm wavelength, enzyme-linked immunosorbent assay, and automated chemistry analyzer, respectively. Analyses were performed using median, mean, Chi-square, correlation, and statistical significance. Results: The median BPb levels were 10.0 µg/dl among participants with about half, 211 (49.3%) having BPb within reference levels. Though the mean values of thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), and creatinine (Cr) were within the reference values, the majority of 275 (64.25%) of the participants had non-euthyroid statuses. Significant differences were found in TSH (P = 0.001), thyroid status (P = 0.0129), and estimated glomerular filtration rate (P = 0.00384) between those with BPb within reference level and those with elevated levels. Conclusion: Though the mean levels of thyroid hormones and Cr were within their respective reference intervals, there was a preponderance of non-euthyroid status among participants in the present study with the majority of the participants falling within CKD grades 2 and 3.

Development of a selective fluorescence derivatization strategy for thyroid hormones based on the Sonogashira coupling reaction.

A new fluorescence derivatization technique for the determination of the thyroid hormones, 3,3',5-triiodo-L-thyronine (T3, triiodothyronine) and 3,3',5,5'-tetraiodo-L-thyronine (T4, L-thyroxine), in human serum was developed based on the Sonogashira coupling reaction. This derivatization reaction was recently utilized by our research group as a promising solution for the derivatization of ortho-substituted aryl halides that suffer from steric hindrance. T3 and T4 possess amino groups that could be derivatized by many reagents; however, these reagents are not useful in the case of biological analysis as they could non-selectively react with many biogenic amines and amino acids. Thus, herein we aimed at labeling the iodo-phenyl group of T3 and T4 as a selective fluorescence labeling approach suitable for biological analysis. The fluorescent alkyne, 2-(4-ethynylphenyl)-4,5-diphenyl-1H-imidazole (DIB-ET), can label the ortho-substituted aryl halides T3 and T4 in the presence of palladium and copper as catalysts, overcoming the steric hindrance of ortho-substitution. Furthermore, the application of the proposed method for the selective analysis of T3 and T4 in biological samples was successfully performed even in the presence of numerous biological components. The formed fluorescent derivatives produced from the reaction of DIB-ET and T3 and T4 could be determined by an HPLC system with fluorescence detection. The proposed method was successfully applied for the selective and sensitive determination of T3 and T4 in human serum with detection limits (S/N = 3) of 4.0 and 6.1 ng/mL and the recovery rate in the ranges of 84.3-92.1% and 81.3-84.9%, respectively. Therefore, the proposed method could be used as a new simple tool for the simultaneous determination of T3 and T4 in biological samples.

Diagnostic performance of Midkine ratios in fine-needle aspirates for evaluation of Cytologically indeterminate thyroid nodules.

BACKGROUND: Fine-needle aspiration cytology (FNAC) is a basic diagnostic tool for thyroid nodules. However, 15-30% of nodules are cytologically indeterminate. Midkine (MK), a pleiotropic growth factor, is often upregulated in patients with cancers. This study aimed to evaluate the role of MK and its ratios in fine-needle aspirates (FNA) for predicting thyroid malignancy. METHODS: This retrospective study included patients with thyroid nodules who underwent preoperative FNA and/or thyroidectomy between April 2017 and September 2017. MK levels in FNA washout were measured by enzyme-linked immunosorbent assay, and thyroglobulin (TG) and free thyroxine (FT4) levels in FNA washout were measured by chemiluminescent immunometric assays. RESULTS: A total of 217 patients with 242 nodules were included in this study. The concentrations of TG, FT4, MK/TG, MK/FT4, and FT4/MK were significantly different between papillary thyroid carcinomas and benign thyroid nodules. Both MK/TG and MK/FT4 ratios were positively correlated with maximum tumor diameter, extrathyroidal extension, and T and N stages. The area under the curve for MK/TG was 0.719 with a cutoff value of 55.57 ng/mg, while the area under the curve for MK/FT4 was 0.677 with a cutoff value of 0.11 µg/pmol. FNAC in combination with MK/FT4 had a higher sensitivity (95% vs. 91%) and accuracy (96% vs. 92%) than FNAC alone for cytologically indeterminate specimens, those of unknown significance, or those suspected of malignancy. CONCLUSIONS: MK/FT4 and MK/TG may have diagnostic utility for evaluation of papillary thyroid carcinomas, particularly for cytologically indeterminate thyroid nodules.

Association of Thyroid Dysfunction With Cognitive Function: An Individual Participant Data Analysis.

Importance: In clinical guidelines, overt and subclinical thyroid dysfunction are mentioned as causal and treatable factors for cognitive decline. However, the scientific literature on these associations shows inconsistent findings. Objective: To assess cross-sectional and longitudinal associations of baseline thyroid dysfunction with cognitive function and dementia. Design, Setting, and Participants: This multicohort individual participant data analysis assessed 114 267 person-years (median, 1.7-11.3 years) of follow-up for cognitive function and 525 222 person-years (median, 3.8-15.3 years) for dementia between 1989 and 2017. Analyses on cognitive function included 21 cohorts comprising 38 144 participants. Analyses on dementia included eight cohorts with a total of 2033 cases with dementia and 44 573 controls. Data analysis was performed from December 2016 to January 2021. Exposures: Thyroid function was classified as overt hyperthyroidism, subclinical hyperthyroidism, euthyroidism, subclinical hypothyroidism, and overt hypothyroidism based on uniform thyrotropin cutoff values and study-specific free thyroxine values. Main Outcomes and Measures: The primary outcome was global cognitive function, mostly measured using the Mini-Mental State Examination. Executive function, memory, and dementia were secondary outcomes. Analyses were first performed at study level using multivariable linear regression and multivariable Cox regression, respectively. The studies were combined with restricted maximum likelihood meta-analysis. To overcome the use of different scales, results were transformed to standardized mean differences. For incident dementia, hazard ratios were calculated. Results: Among 74 565 total participants, 66 567 (89.3%) participants had normal thyroid function, 577 (0.8%) had overt hyperthyroidism, 2557 (3.4%) had subclinical hyperthyroidism, 4167 (5.6%) had subclinical hypothyroidism, and 697 (0.9%) had overt hypothyroidism. The study-specific median age at baseline varied from 57 to 93 years; 42 847 (57.5%) participants were women. Thyroid dysfunction was not associated with global cognitive function; the largest differences were observed between overt hypothyroidism and euthyroidism-cross-sectionally (-0.06 standardized mean difference in score; 95% CI, -0.20 to 0.08; P = .40) and longitudinally (0.11 standardized mean difference higher decline per year; 95% CI, -0.01 to 0.23; P = .09). No consistent associations were observed between thyroid dysfunction and executive function, memory, or risk of dementia. Conclusions and Relevance: In this individual participant data analysis of more than 74 000 adults, subclinical hypothyroidism and hyperthyroidism were not associated with cognitive function, cognitive decline, or incident dementia. No rigorous conclusions can be drawn regarding the role of overt thyroid dysfunction in risk of dementia. These findings do not support the practice of screening for subclinical thyroid dysfunction in the context of cognitive decline in older adults as recommended in current guidelines.

Associations between the thyroid panel and serum protein concentrations across pregnancy.

Establishing any characteristic associations between the serum parameters of thyroid function and serum proteins in pregnancy may aid in elucidating the role of the thyroid gland in the regulation of pregnancy-specific metabolic processes and in selecting candidate biomarkers for use in their clinical assessment. Concentrations of thyroid stimulating hormone (TSH), free tri-iodothyronine (fT3) and free thyroxine (fT4), six electrophoretically separated protein fractions (albumin, alpha-1-, alpha2-, beta-1-, beta-2- and gamma-globulins), representative proteins-albumin (ALB), transferrin (TRF), alpha-2-macroglobulin (AMG) and ceruloplasmin (CER) were measured in 136 serum samples from 65 women in their consecutive trimesters of pregnancy. The concentrations of TSH, fT4 and fT3 were significantly correlated (p < 0.05) with the concentrations of the albumin, alpha-2- and beta-1 globulin fractions. Significant correlations (p < 0.05) which were positive between fT4 and ALB and negative between fT4 and TRF were established throughout pregnancy. Significant negative correlations (p < 0.05) were demonstrated for fT3 with alpha-2-globulin, AMG and CER. Changes in the serum concentrations of thyroid hormones seen between the trimesters were found to correlate with the concentrations of high-abundance serum proteins. Opposite directions of correlations between fT4 and ALB and fT4 and TRF observed throughout pregnancy may indicate the shared biological role of these parameters in maintaining maternal homeostasis and they suggest their potential use in the clinic as a simple biomarker panel. A negative correlation of fT3 with CER in the second trimester possibly reflects their involvement in the active regulation of metabolic processes.

Laboratory interference in the thyroid function test.

Thyroid hormones and thyroid-stimulating hormone (TSH) laboratory tests are commonly used worldwide, and their results have an important influence on decisions about treatment and further diagnostic processes. Any discrepancies between symptoms and laboratory results or between results of different tests should be closely investigated to avoid misdiagnosis and unnecessary treatment. Inconsistencies in hormone tests might be a result of physiological changes in hormonal balance, a disease, drug intake, or laboratory interference. Major factors that interfere with thyroid function tests are: heterophilic antibodies, macro TSH, biotin, thyroid hormones autoantibodies, anti-streptavidin, and anti-ruthenium antibodies. In this paper we discuss the influence of different factors on the procedures of hormonal immunoassays, as well as methods to minimise the risk of false results and misdiagnoses.

Characterization of patients diagnosed with congenital hypothyroidism at the Hospital Universitario San Ignacio between 2001 and 2017 / Caracterización de pacientes con hipotiroidismo congénito en el Hospital Universitario San Ignacio entre 2001 y 2017.

Introduction: Congenital hypothyroidism is a preventable cause of cognitive disability. Due to the absence of symptoms and signs in the newborn, it is necessary to perform screening tests. Its incidence ranges between 1:2,500 and 1:6,000. Objective: To describe the anthropometric and demographic characteristics, as well as the cord TSH levels, serum TSH, and serum T4L levels of the positive patients during screening and patients with confirmed congenital hypothyroidism. Materials and methods: We conducted a retrospective observational study for 17 years based on the review of clinical laboratory and medical records to describe the demographic and anthropometric characteristics of the patients at the time of diagnosis. Results: We analyzed 41,494 newborns in the 17 years of follow-up; 217 (0.52%) were positive in the screening test and the diagnosis was confirmed by serum tests (TSH and free T4) in 19 cases (8.76%) for an incidence of one for every 2,183 live births; 78.95% of the children with congenital hypothyroidism were born full-term and the average gestational age was 37.3 weeks, similar to that of those with no congenital hypothyroidism. There was no difference in the average weight and height at birth between the children with the condition and those who did not have it. TSH in the cord in the cases of congenital hypothyroidism was significantly higher than in the discarded cases. Conclusions: The incidence of congenital hypothyroidism was similar to that found in the literature. There were no relevant clinical differences between confirmed and ruled out cases reflecting the relevance of neonatal screening.

Introducción. El hipotiroidismo congénito es una causa prevenible de discapacidad cognitiva. Dada la ausencia de signos y síntomas al nacer, es necesario hacer pruebas de tamización para detectarlo. Su incidencia oscila entre uno de cada 2.500 y uno de cada 6.000 nacidos vivos. Objetivo. Describir las características antropométricas y demográficas de los participantes, así como medir la concentración de tirotropina (TSH) en sangre de cordón umbilical y de TSH y tiroxina libre (T4 libre) en el suero de los recién nacidos positivos en la prueba de tamización y de aquellos con hipotiroidismo congénito confirmado. Materiales y métodos. Se hizo un estudio observacional retrospectivo de un periodo de 17 años mediante la revisión de los registros de laboratorio clínico y las historias para establecer las características demográficas y antropométricas en el momento del nacimiento. Resultados. Se analizaron 41.494 recién nacidos. Se encontraron 217 (0,52 %) recién nacidos con prueba positiva de tamización, 19 (8,76 %) de ellos con diagnóstico confirmado mediante pruebas séricas (TSH y T4 libre), para una incidencia de uno por cada 2.183 nacidos vivos. El 78,95 % de los casos de hipotiroidismo congénito correspondió a nacidos a término, el promedio de la edad gestacional fue de 37,3 semanas, similar al de quienes no lo presentaban. No hubo diferencia en el promedio de peso ni en la talla al nacer entre los afectados y los no afectados. La concentración de TSH en sangre de cordón umbilical fue significativamente mayor en los casos de hipotiroidismo congénito que en los recién nacidos sanos. Conclusiones. La incidencia de hipotiroidismo congénito fue similar a la encontrada en los estudios consultados. No hubo diferencias clínicas relevantes entre los casos confirmados y los descartados, lo que resalta la pertinencia de la tamización neonatal para el diagnóstico temprano y el tratamiento oportuno.

Study of reference intervals for free triiodothyronine, free thyroxine, and thyroid-stimulating hormone in an elderly Chinese Han population.

The clinical manifestations of thyroid diseases in elderly patients are often atypical. This study aimed to establish reference intervals for thyroid function in the elderly in order to help diagnose thyroid diseases in this population. A total of 5345 healthy individuals were examined and divided into three groups according to their age: 4297 individuals aged < 65 years (19-64), 719 individuals aged between 65 and 79 years, and 329 individuals aged between 80 and 100 years. Levels of free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), thyroid peroxidase antibody, and thyroglobulin antibody were measured in these subjects by using a fully automated analyzer. The following free triiodothyronine, free thyroxine, and thyroid-stimulating hormone reference intervals were obtained from each age group: For individuals aged < 65 years (19-64 years), FT3, FT4, and TSH were 3.40-6.44, 10.26-19.25 pmol/L and 0.50-4.81 µIU/mL, respectively. For individuals aged between 65 and 79 years, FT3, FT4 and TSH ranged between 3.01-5.91, 10.04-19.76 pmol/L, and 0.54-5.51 µIU/mL, respectively. For individuals aged between 80 and 100 years, FT3, FT4, and TSH varied between 2.82-5.57, 9.79-21.22 pmol/L, 0.31-6.28 µIU/mL respectively. FT3 concentration was lower and the concentrations of FT4 and TSH were higher in individuals aged ≥ 65 years than in those aged <65 years (P<0.0001; P = 0.0039; P<0.0001, respectively). In conclusion, establishment of a reference interval would allow clinicians to diagnose diseases more accurately and easily.

Interpretation of thyroid function tests during pregnancy.

Thyroid hormones are crucial for normal pregnancy and fetal development. Large physiological changes occur during pregnancy, posing challenges for the correct interpretation of thyroid function tests. TSH concentrations are the principal first test to rule out thyroid disease taking into account trimester-specific reference ranges. Free T4 (FT4) measurements by immuno-assays may be subject to interference by endogenous and exogenous factors. The relevance of measuring free T3 (FT3) during pregnancy is unclear. Thyroid autoimmunity is well-reflected by the presence of antibodies against TPO. TPO-antibody positivity is associated with an increased risk of adverse pregnancy outcomes.

Altered thyroid hormone profile in patients with Alzheimer's disease.

BACKGROUND: Epidemiological studies have linked higher levels of thyroid hormones (THs) to increased risk of Alzheimer's disease (AD), whereas in advanced AD, THs have been unchanged or even decreased. In early AD dementia, little is known whether THs are related to AD neuropathology or brain morphology. METHODS: This was a cross-sectional study of 36 euthyroid AD patients and 34 healthy controls recruited at a single memory clinic. Levels of THs were measured in serum and cerebrospinal fluid (CSF). In addition, we determined AD biomarkers (amyloid-ß1-42, total tau and phosphorylated tau) in CSF and hippocampal and amygdalar volumes using magnetic resonance imaging. RESULTS: Serum free thyroxine (FT4) levels were elevated, whereas serum free triiodothyronine (FT3)/FT4 and total T3 (TT3)/total T4 (TT4) ratios were decreased, in AD patients compared to controls. In addition, serum TT4 was marginally higher in AD (p = 0.05 vs. the controls). Other TH levels in serum as well as CSF concentrations of THs were similar in both groups, and there were no correlations between THs and CSF AD biomarkers. However, serum FT3 correlated positively with left amygdalar volume in AD patients and serum TT3 correlated positively with left and right hippocampal volume in controls. CONCLUSIONS: Thyroid hormones were moderately altered in mild AD dementia with increased serum FT4, and in addition, the reduced T3/T4 ratios may suggest decreased peripheral conversion of T4 to T3. Furthermore, serum T3 levels were related to brain structures involved in AD development.

Trust your Endocrinologist - Report and Recommendations on the Ordering of Reverse T3 Testing.

Laboratory testing for markers of thyroid function is essential for the diagnosis of thyroid disease, yet, the landscape of thyroid function testing is complex and inappropriate test orders are common. Reverse T3 (rT3) is frequently seen on thyroid function testing menus as a marker of nonthyroidal illness. However, the diagnostic utility of rT3 for this indication is questionable, and testing of rT3 is not recommended by any professional practice guidelines. We reviewed a set of rT3 orders at our institution, and identified that 11 of 20 orders appeared inappropriate with respect to clinical context. These orders were less likely to have been placed at the recommendation of an endocrinologist relative to appropriate orders. We recommend that all providers refer to professional guidelines for thyroid function testing, and consult with an endocrinologist for appropriate usage of esoteric or non-standard thyroid function tests.

Cyclodextrin-based superparamagnetic host vesicles as ultrasensitive nanobiocarriers for electrosensing.

A carbohydrate-based nanohybrid of superparamagnetic nanoparticles embedded in unilamellar bilayer vesicles of amphiphilic ß-cyclodextrins (magnetic cyclodextrin vesicles, mCDVs) has been engineered as a novel magnetic biorecognition probe for electrosensing. As a proof-of-concept, the synergistic properties of these mCDVs on a magneto nanocomposite carbon-paste electrode (mNC-CPE) have been used for the picomolar determination of thyroxine (T4) as a model analyte (taking advantage of the host-guest chemistry of ß-cyclodextrin and T4), resulting in the most sensitive electrochemical T4 system reported in the literature. Accordingly, a first demonstration of mCDVs as alternative water-soluble magnetic nanobiocarriers has been devised foreseeing their successful use as alternative electrochemical biosensing platforms for the supramolecular trace determination of alternative targets.

Flexible MoS2-Polyimide Electrode for Electrochemical Biosensors and Their Applications for the Highly Sensitive Quantification of Endocrine Hormones: PTH, T3, and T4.

Flexibile biosensors have a lot of applications in measuring the concentration of target bioanalytes. In combination with its flexibility, electrochemical sensors containing 2D materials have particular advantages such as enlarged area compatibility, transparency, and high scalability. A flexible biosensor was fabricated by direct synthesis of molybdenum disulfide (MoS2) on a polyimide (PI) substrate, which can be used as the working electrode in electrochemistry platforms. The direct formation of 2D-MoS2 on the PI was achieved using plasma-enhanced chemical vapor deposition (PE-CVD). Since the MoS2 provides higher electrical conductivity, the MoS2-Au-PI flexible sensor is able to provide highly sensitive detection of target proteins with a relatively fast response via cyclic voltammetry. To evaluate the high performance of the fabricated sensor, we selected the endocrine-related hormones parathyroid hormone (PTH), triiodothyronine (T3), and thyroxine (T4) as analytes because they are one of the most important markers for the determination of endocrinopathy, however, they are very difficult to quantify. The newly developed biosensor achieved highly sensitive detection of the hormones and could determine their location with high accuracy. In addition, we performed electrochemical measurements of hormones obtained from 30 clinical patients' sera with confirmed agreement and compared with the measurements performed with standard immunoassay equipment (E 170, Roche Diagnostics, Germany).

Updates on Thyroid Disease in Rabbits and Guinea Pigs.

Hyperthyroidism seems to be a rare, but likely underdiagnosed disease of guinea pigs (Cavia porcellus) and rabbits (Oryctolagus cuniculus). Diagnosis is confounded by nonspecific clinical signs, lack of validated assays, and species-specific reference intervals. With increasing English-language publications on the topic, naturally occurring thyroid disease is likely to be increasingly diagnosed in exotic small mammals. The most consistently observed clinical signs include weight loss with or without a change in appetite and a palpable cervical mass. Diagnosis is supported by elevated blood thyroxine concentrations. Treatment may include thyreostatic agents, radioactive iodine, or surgical thyroidectomy.

Neonatal Thyroxine, Maternal Thyroid Function, and Cognition in Mid-childhood in a US Cohort.

OBJECTIVE: Examine the associations of maternal thyroid hormones, maternal dietary information, and newborn T4 levels with cognitive outcomes in mid-childhood. METHODS: We studied 921 children born 1999-2003 at gestational age ≥ 34 weeks, who were participants in Project Viva, a prospective pre-birth cohort study in Massachusetts. We examined maternal dietary information, maternal thyroid hormone levels, and neonatal levels of T4. Research staff performed cognitive testing in mid-childhood (median age 7.7 years). RESULTS: We included 514 women with measured first trimester thyroid hormone concentrations (mean 10.2 weeks); 15% of women had a thyroid stimulating hormone (TSH) level ≥ 2.5 mU/L, and 71% were college graduates. Newborn T4 was collected from 375 infants (mean 17.6 µg/dl; SD 4.0), on day 2 (mean 1.9 days; SD 0.7) as part of the newborn screening program. Mean (SD) verbal and nonverbal IQ, memory, and motor scores of children were 113.2 (14.3), 107.1 (16.7), 17.1 (4.4), and 92.5 (16.6) points, respectively. In multivariable analysis, first trimester maternal thyroid function (total T3, total T4, free T4, thyroid stimulating hormone (TSH) or total thyroid peroxidase (TPO) antibody levels) or newborn T4 were not associated with any of the cognitive outcomes in mid-childhood after adjustment for sociodemographic and perinatal variables. CONCLUSIONS FOR PRACTICE: Maternal or neonatal thyroid hormone levels were not associated with cognitive outcomes in mid-childhood in this population with generally normal thyroid function. As we studied a highly educated cohort residing in an iodine-sufficient area, findings may not be generalizable.

Cuidado con la biotina: un problema creciente en la práctica clínica / Awareness of biotin: A growing problem in clinical practice

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Ultra performance liquid chromatography - tandem mass spectrometer method applied to the analysis of both thyroid and steroid hormones in human hair.

Hair is increasingly used as a biological matrix of interest for the assessment of hormone secretion over extended periods of time. This study described the development and the validation of a sensitive UPLC-MS/MS method for simultaneous analysis of steroid and thyroid hormones in human hair. The gradient designed in this method enables to obtain a satisfactory separation of 9 hormones of interest: cortisol, cortisone, THE, THF, α-THF, triiodothyronine (T3) and thyroxine (T4), estradiol, and testosterone. Several methodological parameters of extraction (such as the used of "cut hair" versus "pulverized hair", the extraction time, the incubation solvent purification on SPE column and hydrolysis) that may influence the determination of hormones levels in human hair, have thus been tested here. Therefore, the results obtained highlighted the necessity of using a C18 SPE purification method for the determination of both steroid and thyroid hormones in hair. This method allows reaching suitable levels of sensitivity for cortisol and cortisone since the results obtained pointed out concentration levels of cortisol in hair of volunteers similar to those observed in the literature. This method could also offer an important impact in the field of hormone analysis since it allows, for the first time, the quantification of both T3 and T4 in human hair.