PTH immunoassay interference: differential diagnosis with normocalcemic primary hyperparathyroidism?

The main diagnostic dilemma in normocalcemic hyperparathyroidism is differentiating this condition from secondary hyperparathyroidism and other causes of elevated parathyroid hormone (PTH) levels in eucalcemic patients, including potential assay interferences. Despite the analytical sensitivity of immunoassays, they may lack adequate accuracy due to several analytical interferences, such as the presence of heterophilic antibodies. Immunoassays for PTH measurement use the immunometric "sandwich" technique, and only a few cases of interference with this assay have been reported to date.

Alert for the high prevalence of vitamin D deficiency in adolescents in a large Brazilian sample.

Objective: To estimate the prevalence of vitamin D deficiency and severe deficiency in children and adolescents, in a large Brazilian sample.

Methodology: Results of 413,988 25(OH)D measurements in children and adolescents aged 0 to 18 years collected between 01/2014 and 10/2018 were obtained from the database of a Clinical Laboratory. In this population, 25 hydroxyvitamin D concentrations below 20 ng/mL are considered deficient, and below 12 ng/mL as severe deficiency.

False diagnosis of recurrent thyroid carcinoma: the importance of testing for heterophile antibodies.

Thyroglobulin (Tg) levels are important to predict recurrence in differentiated thyroid cancer patients.However, false-positive results can hence the request of unnecessary tests and treatments. We reported two cases of interference in thyroglobulin measurement and the workup to investigate them.

Thyroid dysfunction alters gene expression of proteins related to iron homeostasis and metabolomics in male rats.

Thyroid hormones (THs) are crucial in bodily functions, while iron is essential for processes like oxygen transport. Specialized proteins maintain iron balance, including ferritin, transferrin, ferroportin, and hepcidin. Research suggests that THs can influence iron homeostasis by affecting mRNA and protein expression, such as ferritin and transferrin.

Metabolomic analysis of follicular fluid from women with Hashimoto thyroiditis.

Hashimoto thyroiditis is an autoimmune disease characterized by hypothyroidism and a high level of anti-thyroid autoantibodies. It has shown to negatively impact female fertility; however, the mechanisms are unclear. Ovarian follicular fluid appears to be the key to understanding how Hashimoto thyroiditis affecst fertility.

Treatment of Graves' disease in Brazil: results of a survey among endocrinologists.

Objective: The objective of the study was to determine how physicians in Brazil manage Graves' disease in different scenarios including extrathyroidal manifestations.

Materials And Methods: This study was conducted via a digital survey. The respondents (n = 573) answered multiple-choice questions based on a clinical case and variations of the case regarding laboratory and imaging evaluation, treatment choice, and follow-up.

Alternation between toxic and proliferative effects of Roundup® on human thyroid cells at different concentrations.

Endocrine-disrupting and carcinogenic effects of glyphosate have long been suspected, but little is known about the effect of compounds used in real life at different concentrations, neither in normal nor in thyroid tumor cells. As cancer cells may have different sensitivities and the effect of the product containing glyphosate may be different from that produced by the active ingredient alone, including the Acceptable Occupational Exposure Level (AOEL=160µg/L) and the Acceptable Daily Intake (ADI=830µg/L) determined by ANVISA, we used two human thyroid-derived cell lines, Nthy-ori 3-1 (from normal follicular cells) and TPC-1 (from papillary carcinoma), to test 15 different concentrations of Roundup® Original DI. Trypan blue (TB), CCK-8 and BrdU assays were used to evaluate cytotoxicity, metabolic activity and proliferation with 24h and 48h exposures in technical and biological triplicates.

No association between vitamin D status and COVID-19 infection in São Paulo, Brazil.

In recent years the immunomodulatory actions of vitamin D, a steroid hormone, have been extensively studied. In 2020, due to the COVID-19 pandemic, the question arose as to 25(OH)D status would be related to susceptibility to SARS-CoV-2 infection, since several studies pointed out a higher prevalence and severity of the disease in populations with low levels of 25(OH)D. Thus, we investigated the 25(OH)D levels in adults "Detected" positive for SARS CoV-2 by RT-PCR (reverse transcriptase polymerase chain reaction) test, and in negative controls, "not Detected", using the Fleury Group's examination database, in Sao Paulo, Brazil.

Intergenerational thyroid hormone homeostasis imbalance in cerebellum of rats perinatally exposed to glyphosate-based herbicide.

Agrochemicals became a public health concern due to increased human exposure and possible endocrine disruption effects in several organs, including the brain. Thyroid hormones controls neurodevelopment, which turn them sensitive to endocrine disruptors (EDs). In this work, we evaluated the effect of glyphosate-based herbicides (GBH) as an intergenerational endocrine disrupter on thyroid homeostasis in cerebellar cells.

Androgens by immunoassay and mass spectrometry in children with 46,XY disorder of sex development.

Objective: Steroid measurement is a challenge in pediatric endocrinology. Currently, liquid chromatography with tandem mass spectrometry (LC-MS/MS) is considered a gold standard for this purpose. The aim of this study was to compare both LC-MS/MS and immunoassay (IA) for androgens before and after human recombinant chorionic gonadotropin (rhCG) stimulus in children with 46,XY disorders of sex development (DSD).

Thyroxine replacement modifies changes in deiodinase and thyroid hormone transporter expression induced by subclinical hypothyroidism in rats.

Purpose: The potential benefits of treating subclinical hypothyroidism (SCH) are unclear and still controversial. Thus, we surgically induced SCH in rats and evaluated the effects of thyroxine (T) replacement on the gene expression levels of deiodinases and thyroid hormone (TH) transporters in different tissues.

Methods: SCH was induced by hemithyroid electrocauterization.

Structural insights revealed by two novel THRB mutations.

Purpose: Among the inheritable forms of impaired sensitivity to thyroid hormone, resistance to thyroid hormone (RTH) due to mutations in the thyroid hormone receptor beta gene (THRB) is the first and best known described defect, revealing a wide phenotypic variability with an incompletely understood physiopathology. The objective of this study was to evaluate two novel mutations in THRB, N331H and L346R, in an attempt to provide a rational understanding of the harmful effects caused by them.

Methods: The mutations of two patients with RTHβ were reproduced for analysis of gene transactivation by dual-luciferase reporter assay, and for molecular modeling for crystallography-based structural assessment.

Evaluation of neuroglobin and cytoglobin expression in adult rats exposed to silver nanoparticles during prepubescence.

Silver nanoparticles (AgNPs) are clusters of silver atoms with diameters that range from 1 to 100 nm. Due to the various shapes and large surface areas, AgNPs have been employed in the food and textile industries and medical fields. Therefore, because of the widespread use of these compounds, the aim of this study was to evaluate the effect of AgNP exposure on the gene and protein expression levels of Neuroglobin (Ngb) and Cytoglobin (Cygb), in the rat cortex, hippocampus and cerebellum.

Thyroid Function Disruptors: from nature to chemicals.

The modern concept of thyroid disruptors includes man-made chemicals and bioactive compounds from food that interfere with any aspect of the hypothalamus-pituitary-thyroid axis, thyroid hormone biosynthesis and secretion, blood and transmembrane transport, metabolism and local action of thyroid hormones. This review highlights relevant disruptors that effect populations through their diet: directly from food itself (fish oil and polyunsaturated fatty acids, pepper, coffee, cinnamon and resveratrol/grapes), through vegetable cultivation (pesticides) and from containers for food storage and cooking (bisphenol A, phthalates and polybrominated diphenyl ethers). Due to the vital role of thyroid hormones during every stage of life, we review effects from the gestational period through to adulthood, including evidence from in vitro studies, rodent models, human trials and epidemiological studies.

Novel immunoassay for TSH measurement in rats.

Measuring thyroid hormones is an important aspect for the study of metabolism and for monitoring diseases in both human and animal models. The traditional method for hormone measurement in rats is the radioimmunoassay (RIA). However, the RIA is associated with some practical disadvantages, including the use of radioactive material, the need for specialized equipment and expert staff, the short shelf-life of kits according to the half-life of the radioisotope and high costs.

Anatomical specificity of the brain in the modulation of Neuroglobin and Cytoglobin genes after chronic bisphenol a exposure.

The aim of this study was to investigate the influence of Bisphenol A (BPA) exposure on Neuroglobin (Ngb) and Cytoglobin (Cygb) as well as oxidative stress gene expression in the cerebellum, hippocampus, hypothalamus and cortex. Male Wistar rats were randomly divided into 3 groups: Control and two groups receiving 2 different daily BPA dosages, 5 or 25 mg/kg from postnatal day 50 (PND50) through PND90 and they were euthanized at PND105. In the cortex, we found an increase in Ngb gene expression and also in superoxide dismutase 1 and Catalase (Cat).

Perinatal exposure to glyphosate-based herbicide alters the thyrotrophic axis and causes thyroid hormone homeostasis imbalance in male rats.

Glyphosate-based herbicides (GBHs) are widely used in agriculture. Recently, several animal and epidemiological studies have been conducted to understand the effects of these chemicals as an endocrine disruptor for the gonadal system. The aim of the present study was to determine whether GBHs could also disrupt the hypothalamic-pituitary-thyroid (HPT) axis.

The absence of mutations in homeobox candidate genes HOXA3, HOXB3, HOXD3 and PITX2 in familial and sporadic thyroid hemiagenesis.

Background: The molecular mechanisms leading to the formation of the two thyroid symmetrical lobes, which are impaired in thyroid hemiagenesis (TH), are little known.

Objective: The aim of this work was to search for mutations in thyroid developmental candidate genes HOXA3, HOXB3, HOXD3 and PITX2.

Methods: Total DNA from peripheral blood was extracted and then the entire coding region of all these genes was amplified by polymerase chain reaction and direct sequencing.

Ion channelopathies in endocrinology: recent genetic findings and pathophysiological insights.

Ion channels serve diverse cellular functions, mainly in cell signal transduction. In endocrine cells, these channels play a major role in hormonal secretion, Ca(2+)-mediated cell signaling, transepithelial transport, cell motility and growth, volume regulation and cellular ionic content and acidification of lysosomal compartments. Ion channel dysfunction can cause endocrine disorders or endocrine-related manifestations, such as pseudohypoaldosteronism type 1, Liddle syndrome, Bartter syndrome, persistent hyperinsulinemic hypoglycemia of infancy, neonatal diabetes mellitus, cystic fibrosis, Dent's disease, hypomagnesemia with secondary hypocalcemia, nephrogenic diabetes insipidus and, the most recently genetically identified channelopathy, thyrotoxic hypokalemic periodic paralysis.

Minireview: Thyrotropin-releasing hormone and the thyroid hormone feedback mechanism.

Thyroid hormone (TH) plays a critical role in development, growth, and cellular metabolism. TH production is controlled by a complex mechanism of positive and negative regulation. Hypothalamic TSH-releasing hormone (TRH) stimulates TSH secretion from the anterior pituitary.

Clinical and molecular analysis of thyroid hypoplasia: a population-based approach in southern Brazil.

Background: Congenital hypothyroidism (CH) is mainly due to developmental abnormalities leading to thyroid dysgenesis (TD). TD encompasses very distinct morphologic subtypes of disease. This study examined and compared the phenotype in TD variants and searched for genetic alterations in sporadic thyroid hypoplasia (TH), the most misdiagnosed form of CH.