Metacognitive self-assessment scale: psychometric properties and clinical implications.

Metacognition is a higher-order psychological construct that has been conceptualized as the ability to identify and describe mental states, beliefs, and intentions of self and others. The Metacognition Self-Assessment Scale (MSAS), was developed to assess different functions of metacognition, being a potential asset in fields such as psychotherapy and clinical neuropsychology. However, a reliability and validity study is still lacking, as well, the study with other related metacognitive constructs. This research describes the psychometric analysis of the MSAS in a cross-sectional design and the study of the relationship between metacognitive functions, meta-beliefs and cognitive fusion. The sample comprised 194 participants from the general population (76% women), with an average age of 32 years old. Exploratory factor analysis, Cronbach alpha, test-retest, and validity procedures through bivariate correlations with convergent/divergent measures were conducted. The scale showed satisfactory psychometric properties with good internal consistency along with appropriate convergent/divergent validity. Metacognition and cognitive fusion were negatively correlated, while negative meta-beliefs and mastery predicted the variance of cognitive fusion. Decentering-differentiation factor correlated negatively with cognitive fusion and personal discomfort. These results suggest that MSAS may be a reliable tool to assess metacognition in the Portuguese population. Clinical implications are discussed.

In Vitro Assessment of the Efficacy of a Macrocyclic Chelator in Reversing Methylmercury Toxicity.

Methylmercury (MeHg) is a highly neurotoxic compound to which human populations are exposed via fish consumption. Once in cells, MeHg actively binds thiols and selenols, interfering with the activity of redox enzymes such as thioredoxin (Trx) and the selenoenzyme thioredoxin reductase (TrxR) which integrate the thioredoxin system. In fact, it has been shown that inhibition of this system by MeHg is a critical step in the unfolding of cell death. Current clinical approaches to mitigate the toxicity of MeHg rely on the use of chelators, such as meso-2,3-dimercaptosuccinic acid (DMSA) which largely replaced British anti-Lewisite or 2,3-dimercapto-1-propanol (BAL) as the prime choice. However, therapeutic efficacy is limited and therefore new therapeutic options are necessary. In this work, we evaluated the efficacy of a macrocyclic chelator, 1-thia-4,7,10,13-tetraazacyclopentadecane ([15]aneN4S), in preventing MeHg toxicity, namely by looking at the effects over relevant molecular targets, i.e., the thioredoxin system, using both purified enzyme solutions and cell experiments with human neuroblastoma cells (SH-SY5Y). Results showed that [15]aneN4S had a similar efficacy to DMSA and BAL in reversing the inhibition of MeHg over purified TrxR and Trx by looking at both the 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) reduction assay and insulin reduction capability. In experiments with cells, none of the chelating agents could reverse the inhibition of TrxR by MeHg, which corroborates the high affinity of MeHg to the selenol in TrxR active site. [15]aneN4S and BAL, unlike DMSA, could prevent inhibition of Trx, which allows the maintenance of downstream functions, although BAL showed higher toxicity to cells. Overall these findings highlight the potential of using [15]aneN4S in the treatment of MeHg poisoning and encourage further studies, namely in vivo.

Risk assessment of methylmercury in pregnant women and newborns in the island of Madeira (Portugal) using exposure biomarkers and food-frequency questionnaires.

Methylmercury (MeHg) is a contaminant present in fish which exerts a severe impact on health predominantly exhibiting neurotoxicity that might irreversibly affect fetal neurodevelopment. Fish consumption in Portugal is the third highest in the world, particularly high in regions with fishing tradition such as the Madeira Archipelago. Therefore, this study aimed at assessing the risk of exposure to MeHg in a population of pregnant women residing in Madeira. Blood samples from pregnant women (533) and umbilical cord (194) were collected from volunteer participants collected at primary health services in Madeira (Portugal) and analyzed for total mercury (HgT) level. A food-frequency questionnaire was used to estimate exposure and indices of risk while HgT in blood were correlated with estimated exposure. Analysis of HgT levels in blood indicated that 30% of pregnant women surpassed the maximum safe level of 10 µg/L recommended by the WHO, which was derived from the consumption of predatory fish, rich in MeHg. In addition, HgT levels in cord blood were 1.3 fold higher than in maternal blood, indicating the high risk of exposure to MeHg in this population. It is thus important to provide nutritional advice concerning fish consumption as a food choice in order to reduce fetal exposure and potential neurologic damage.

Assessment of total and organic mercury levels in blue sharks (Prionace glauca) from the south and southeastern Brazilian coast.

Mercury occurrence was evaluated in samples of edible muscle tissue of 27 blue sharks (Prionace glauca) caught in the Atlantic Ocean, adjacent to the south and southeastern Brazilian coast, indicating a slight increase in comparison with previous data obtained for the same studied area and being higher than those fish caught at different sites of the Atlantic Ocean. Total Hg concentrations ranged from 0.46 to 2.40 mg kg(-1) with the organic Hg fraction ranging between 0.44 and 2.37 mg kg(-1). A negative correlation between total Hg concentration in muscle tissue and blue shark size was obtained, and 40% of samples analyzed had Hg concentrations higher than 1.0 mg kg(-1) Hg, the maximum concentration permitted in Brazilian predator fish. Data obtained showed that total Hg can be used as a reliable predictor of organic Hg in blue shark muscle because 95 to 98% of the total Hg measured was found to be organic mercury. The wide range of Hg concentrations obtained for our set of samples can be explained by the heterogeneity of sampled population and the large size of the studied area. Given the adverse toxicological effects of Hg on animals and humans, a regular monitoring program of Hg contamination in Brazilian marine ecosystem can be recommended.