Evaluation of redox profiles in exogenous subclinical hyperthyroidism at two different levels of TSH suppression

ABSTRACT Objective: Evaluate the relationship between exogenous subclinical hyperthyroidism and oxidative stress through the analysis of the redox profile of patients with subclinical hyperthyroidism exogenous (SCH) grade I (TSH = 0.1 to 0.4 IU/mL) and grade II (TSH < 0.1 IU/mL). Subjects and methods: We analyzed 46 patients with SCH due to the use of TSH suppressive therapy with LT4 after total thyroidectomy along with 6 control euthyroid individuals (3M and 3W). Patients were divided into two groups, G1 with TSH ≥ 0.1-0.4 IU/mL (n = 25; and 7M 14W) and G2 with TSH < 0.1 IU/mL (n = 25; and 4M 21W). Venous blood samples were collected to measure the levels of markers for oxidative damage (TBARS, FOX and protein carbonylation), muscle and liver damage (CK, AST, ALT, GGT) and antioxidants (GSH, GSSG and catalase). Results: Individuals in G2 showed a GSH/GSSG ratio ~ 30% greater than those in G1 (p = 0.004) and a catalase activity that was 4 times higher (p = 0.005). For lipid peroxidation, the levels measured in G2 were higher than both control and G1 (p = 0.05). No differences were observed for both protein carbonyl markers. G1 and G2 presented with greater indications of cell injury markers than the control group. Conclusion: TSH suppression therapy with LT4 that results in subclinical hyperthyroidism can cause a redox imbalance. The greater antioxidant capacity observed in the more suppressed group was not sufficient to avoid lipid peroxidation and cellular damage.

Influence of Bottle-Feeding on Serum Bisphenol A Levels in Infants

Exposure to endocrine disrupting chemicals (EDCs), particularly during developmental periods, gives rise to a variety of adverse health outcomes. Bisphenol A (BPA) is a well-known EDC commonly found in plastic products including food and water containers, baby bottles, and metal can linings. This study investigates infant exposure to BPA and the effect of bottle-feeding on serum BPA levels in infants. Serum BPA levels in normal healthy infants 6 to 15 months of age (n=60) were evaluated by a competitive ELISA. BPA was detected in every study sample. Serum BPA levels of bottle-fed infants (n=30) were significantly higher than those of breast-fed infants (n=30) (96.58+/-102.36 vs 45.53+/-34.05 pg/mL, P=0.014). There were no significant differences in serum BPA levels between boys (n=31) and girls (n=29). No significant correlations were found between serum BPA levels and age, body weight, birth weight, and gestational age. Bottle-feeding seems to increase the risk of infant exposure to BPA. Establishment of health policies to reduce or prevent BPA exposure in infants is necessary.

Evaluation of blood Bisphenol A contents: a case study / Evaluación de las concentraciones de Bisfenol A en la sangre: estudio de caso

OBJECTIVE: It has been recently reported that Bisphenol A (BPA) may leach out into food, beverages and water samples from the plastic ware in which it is stored. Serious health hazards have been reported from BPA. The purpose of this study is to assess the BPA contents in blood and to assess the risk of cancer. METHOD: A total of 100 individuals were selected for study according to the following five age groups: 5-10, 11-20, 21-30, 31-40 and 41-50 years. They were then further divided into normal and diseased. Age, gender, education, source of drinking water, type of food, smoking habit, any exposure to chemicals and history of cancer were elicited during interview. Blood samples were collected and processed for analysis using reversed phase-high performance liquid chromatography (rp-HPLC) in isocratic mode. The mobile phase consisted of acetonitrile and water (1:1) at a flow-rate of 1 ml min-1. RESULTS: Bisphenol A contents found in blood samples of all age groups ranged from 1.53-3.98 (mean = 2.94, SD = 0.9). P-values, for the exposed people and those having a history of cancer, were < 0.05 showing a significant relationship between BPA and cancer. The United States Environmental Protection Agency (US EPA) has established a reference dose of 50 µg/L. Odd ratios and relative risk for smoking habit were < 1 while for all others they were > 1. CONCLUSION: It was concluded from the study that people using bottled water, packaged food, having a history ofcancer and who had been exposed to any type ofchemicals are at higher risk ofdisease.

OBJETIVO: Se ha reportado recientemente que el bisfenol A (BPA) puede filtrarse a alimentos, bebidas y agua, a partir de los recipientes plásticos en que aquellos se almacenan. En tal sentido, se han reportado serios casos de riesgo para la salud a causa del BPA. El propósito de este estudio es evaluar la concentración de BPA en sangre, y el consiguiente riesgo de enfermedades cancerosas. MÉTODO: Un total de 100 individuos fueron seleccionados para el estudio, de acuerdo con los siguientes cinco grupos etarios: 5-10, 11-20, 21-30, 31-40 y 41-50 años. Dichos grupos fueron divididos entonces sobre la base de sujetos normales frente a enfermos. En la entrevista se tomó nota de la edad, el género, la educación, la fuente de agua potable, el tipo de comida, el hábito de fumar, cualquier exposición a productos químicos, así como la historia de cáncer. Las muestras de sangre fueron recogidas y procesadas para realizar análisis, utilizando cromatografía líquida de alta eficacia de fase reversa (rp-HPLC) en modo isocrático. La fase móvil consistió en acetonitrilo y agua (1:1) con una tasa de flujo de 1 ml min-1. RESULTADOS: Las concentraciones de bisfenol-A halladas en las muestras de sangre de todos los grupos etarios, oscilaron de 1.53 - 3.98 (M = 2.94, SD = 0.9). Los valores P para las personas expuestas y con una historia de cáncer, fueron < 0.05, indicando una relación directa entre el BPA y el cáncer. La Agencia de Protección Ambiental de los Estados Unidos (US EPA) ha establecido una dosis de referencia de 50 µg/L. El cociente de probabilidades (odd ratios) y el riesgo relativo con respecto al hábito de fumar fueron < 1 mientras que para todos los otros casos otros fueron >1. CONCLUSIÓN: A partir del estudio se concluye que las personas que usan agua embotellada, alimentos empaquetados, así como las personas que poseen una historia de cáncer, y los individuos que habían estado expuestos a cualquier tipo de productos químicos, presentan un mayor riesgo de enfermedad.

Urinary, Circulating, and Tissue Biomonitoring Studies Indicate Widespread Exposure to Bisphenol A / Estudos de biomonitoração do sistema urinário, circulatório e tecidos indicam grande exposição ao Bisfenol A

Bisphenol A (BPA) is one of the highest-volume chemicals produced worldwide, and human exposure to BPA is thought to be ubiquitous. Thus, there are concerns that the amount of BPA to which humans are exposed may cause adverse health effects. We examined many possibilities for why biomonitoring and toxicokinetic studies could come to seemingly conflicting conclusions. More than 80 published human biomonitoring studies that measured BPA concentrations in human tissues, urine, blood, and other fluids, along with two toxicokinetic studies of human BPA metabolism were examined. Unconjugated BPA was routinely detected in blood (in the nanograms per milliliter range), and conjugated BPA was routinely detected in the vast majority of urine samples (also in the nanograms per milliliter range). In stark contrast, toxicokinetic studies proposed that humans are not internally exposed to BPA. Available data from biomonitoring studies clearly indicate that the general population is exposed to BPA and is at risk from internal exposure to unconjugated BPA. The two toxicokinetic studies that suggested human BPA exposure is negligible have significant deficiencies, are directly contradicted by hypothesis-driven studies, and are therefore not reliable for risk assessment purposes.

Bisfenol A (BPA) é um dos produtos químicos mais produzido em todo o mundo, e a exposição humana a ele é considerada onipresente. Assim, há preocupações de que a quantidade de BPA para o qual os seres humanos estão expostos podem causar efeitos adversos à saúde. Nós examinamos muitas possibilidades sobre o porquê estudos de biomonitorização e toxicocinética podem chegar a conclusões aparentemente conflitantes. Mais de 80 estudos publicados de biomonitorização humana que mediram a concentração de BPA em tecidos humanos, urina, sangue e outros fluidos, juntamente com dois estudos de toxicocinética do metabolismo humano BPA foram examinados. BPA não conjugado foi detectado no sangue (nonanogramas por mililitro gama), e BPA conjugado foi detectado na grande maioria das amostras de urina. Em contraste, estudos de toxico-cinética propuseram que os seres humanos não são internamente expostos ao BPA. Dados disponíveis de estudos de biomonitorização indicam que a população em geral está exposta ao BPA e em risco de exposição interna ao BPA não conjugado. Os dois estudos de toxicocinética, que sugeriram a exposição humana ao BPA é insignificante, têm deficiências significativas e estão diretamente refutados por outros estudos e, portanto não são confiáveis para fins de avaliação de risco.