Toxicity of silver nanoparticles on different tissues in adult Danio rerio

Although silver nanoparticles (AgNP) are among the most studied nanomaterials by virtue of their broad application in many areas, little is known about their overall toxicity to aquatic organisms after their contamination of the water environment. This study aimed to analyze the effect of the exposure (96 h) to different AgNP concentrations on Danio rerio (zebrafish) tissues. AgNP were synthesized and characterized by transmission electron microscopy (TEM), showing spherical AgNP of 30.00 ± 16.80 nm size. The effects of different AgNP concentrations (1, 3, and 5 μg L^-1) on brain, muscle, gill, and liver tissues of zebrafish were investigated. The results show a significant decrease in brain and muscle acetylcholinesterase (AChE) activity. Liver and gill catalase (CAT) activity also decreased significantly. At the highest exposure concentration, muscle AChE was more inhibited (37.3%) than brain AChE (26.4%) and gill CAT was more inhibited (67.4%) than liver CAT (51.2%). D. rerio also showed gill morphological changes such as fusion of secondary lamellae, curvature, dilated marginal channel, and epithelial lifting. This study indicates that gill CAT together with morphological studies are potential biomarkers for AgNP.

Mechanomyography signals in spastic muscle and the correlation with the modified Ashworth scale

The modified Ashworth scale (MAS) is the most widely used measurement technique to assess levels of spasticity. In MAS, the evaluator graduates spasticity considering his/her subjective analysis of the muscular endurance during passive stretching. Therefore, it is a subjective scale. Mechanomyography (MMG) allows registering the vibrations generated by muscle contraction and stretching events that propagate through the tissue until the surface of the skin. With this in mind, this study aimed to investigate possible correlations between MMG signal and muscle spasticity levels determined by MAS. We evaluated 34 limbs considered spastic by MAS, including upper and lower limbs of 22 individuals of both sexes. Simultaneously, the MMG signals of the spastic muscle group (agonists) were acquired. The features investigated involved, in the time domain, the median energy (MMGME) of the MMG Z-axis (perpendicular to the muscle fibers) and, in the frequency domain, the median frequency (MMG_mf). The Kruskal-Wallis test (p<;0.001) determined that there were significant differences between intergroup MAS spasticity levels for MMG_me. There was a high linear correlation between the MMG_me and MAS (R²=0.9557) and also a high correlation as indicated by Spearman test (ρ=0.9856; p<;0.001). In spectral analysis, the Kruskal-Wallis test (p = 0.0059) showed that MMG_mf did not present significant differences between MAS spasticity levels. There was moderate linear correlation between MAS and MMG_mf (R²=0.4883 and Spearman test [ρ = 0.4590; p <; 0.001]). Between the two investigated features, we conclude that the median energy is the most viable feature to evaluate spasticity due to strong correlations with the MAS.

Apathy is not associated with performance in brief executive tests in patients with mild cognitive impairment and mild Alzheimer's disease

Neuropsychological correlates of apathy in Alzheimer's disease (AD) may shed some light on the neurobiology of this behavioral disorder. Whereas previous research has suggested an association between apathy and executive functions in AD, amnestic mild cognitive impairment (aMCI) cohorts point to an association with memory tests. We aimed to further investigate this issue in a sample of low educated, hitherto unexposed to cholinesterase inhibitors, aMCI (n=26) and mild AD (n=28) patients using brief executive tests, namely the Executive Interview (EXIT-25) and the Frontal Assessment Battery (FAB). Patients and controls (n=33) were included from a community-based survey of successful brain aging in Brazilian elderly (75+ years), The Pietà Study. The participants were submitted to a comprehensively neuropsychological assessment and apathy evaluation through the Apathy Scale (AS).We found a strong correlation in AD group between AS scores and functional performance measured by the Disability Assessment in Dementia (rho =-0.7 ; p<0,001). No association was found between any executive test performance and apathy symptoms. Apathy symptoms were also associated with the performance in memory tests and in the attention subscale of the Mattis Dementia Rating Scale. These findings reinforce the functional effect of apathy even in the mildest stages along the AD cognitive impairment spectrum, and challenges previous assumptions regarding the association between apathy and classical executive functions.

Monitoring of metals, organic compounds and coliforms in water catchment points from the Sinos River basin

Unplanned use and occupation of the land without respecting its capacity of assimilation and environmental purification leads to the degradation of the environment and of water used for human consumption. Agricultural areas, industrial plants and urban centres developed without planning and the control of effluent discharges are the main causes of water pollution in river basins that receive all the liquid effluents produced in those places. Over the last decades, environmental management has become part of governmental agendas in search of solutions for the preservation of water quality and the restoration of already degraded resources. This study evaluated the conditions of the main watercourse of the Sinos River basin by monitoring the main physical, chemical and microbiological parameters described in the CONAMA Resolution no. 357/2005.The set of parameters evaluated at five catchment points of water human consumption revealed a river that has different characteristics in each reach, as the upper reach was class 1, whereas the middle and lower reaches of the basin were class 4. Monitoring pointed to households as the main sources of pollutants in those reaches, although metals used in the industrial production of the region were found in the samples analyzed.

Effect of kinin B2 receptor ablation on skeletal muscle development and myostatin gene expression

Bradykinin (BK) is an active peptide that binds to the kinin B(2) receptor and induces biological events during the development and adult life. In this study we aimed to investigate the effect of kinin B(2) receptor ablation in the postnatal skeletal muscle development and body composition in adult life. For studies of skeletal muscle development, control (C57Bl6 - WT) and B(2) receptor knockout mice (B(2)(-/-)) were sacrificed at 15, 30 and 90days after birth, the gastrocnemius skeletal muscle was weighed and myostatin gene expression evaluated by real time PCR. For energy balance determination, data from control and B(2)(-/-) at 90 and 120days were collected by calorimetric method. Body composition at 120days was determined by chloroform-methanol (total body fat) and Lowry-modified method (total body protein). The results show that B(2)(-/-) have significantly increased total body weight at 15, 30 and 90days of life, when compared to WT. The weight of the gastrocnemius skeletal muscle was also significantly increased at 30 and 90days of life. Body composition analyses revealed that B(2)(-/-) mice exhibit more total corporal protein and less total corporal fat. Energy balance revealed that B(2)(-/-) have increased metabolizable energy intake and energy expenditure when compared to control mice, resulting in a lower energy gain. Interestingly, myostatin mRNA expression was significantly decreased in 15 and 30days old B(2)(-/-) mice and after icatibant treatment of WT adult mice for 5days. In conclusion, together our results show that kinin B(2) receptor deletion increases lean mass, reduces fat mass and improves metabolism efficiency in mice. The mechanism involved in this phenotype could be related to the reduction of myostatin gene expression during postnatal life.

Normative data for healthy elderly on the phonemic verbal fluency task - FAS

Phonemic verbal fluency tests assess the production of words beginning with specific letters. Of these letters, the most frequently used are F, A and S. It is a sensitive test for assessing frontal lobe functions.

Objective

To provide normative data for the elderly Brazilian population on the FAS test and to investigate the effects of age and schooling on test performance.

Methods

The individuals were divided into three age groups (60-69, 70-79 and =80 years), and into four groups according to education (1-3, 4-7, 8-11 and 12 years). All subjects were assessed by the Mini Mental State Examination and the FAS. Data were analyzed with Student's t test, ANOVA, simple linear regression and Spearman's correlation.

Results

We evaluated 345 cognitively healthy volunteers, 66.66% being female, aged 60 to 93 years, with an educational level ranging from one to 24 years. The average (number of items) ±SD for the whole sample was 28.28±11.53. No significant effect of gender was observed (p=0.5). Performance on the MMSE and education exerted a direct influence on FAS scores (p<0.001), with education being the most significant factor. A positive correlation was found between FAS and the MMSE (r=0.404; p<0.001).

Conclusion

The performance of Brazilian elderly on the phonemic verbal fluency tests-FAS is significantly influenced by education, where individuals with higher educational level present better performance than those with fewer years of schooling. Age and gender did not prove significant with the FAS.

Bradykinin-related peptides from Phyllomedusa hypochondrialis

Bradykinin related peptides (BRPs) present in the water-soluble secretion and freshly dissected skin fragments of Phyllomedusa hypochondrialis were investigated by mass spectrometry techniques. Eighteen BRPs, along with their post-translational modifications, were characterized in the secretion by de novo MS/MS sequencing and direct MALDI imaging experiments of the frog skin. These molecules revealed strong sequence similarities to the main plasma kinin of some mammals and reptiles. Such a diversity of molecules, within the same peptide family, belonging to a single amphibian species may be related to functional specializations of these peptides and a variety of corresponding receptors that might be present in a number of different predators. Also, a novel analog, [Val]1,[Thr]6-bradykinyl-Gln,Ser had its biological activity positively detected in cell culture expressing the human bradykinin B2 receptor and in guinea pig ileum preparations.