Before the Dam: A Fish-Mercury Contamination Baseline Survey at the Xingu River, Amazon Basin Before the Belo Monte Dam.

In the last decades, mega-diverse rivers worldwide (e.g., the Amazon and their tributaries) have experienced several human-driven transformations, although impact assessments oftentimes lack baseline data or reference values to better estimate observed disturbances. Herein, we assessed THg and δ15N in fish muscle tissue to determine biomagnification processes, also including seasonal assessments, concerning Hg in fish from the Belo Monte reservoir, located on the Xingu River, prior to its impoundment. A total of 312 samples from 19 fish species belonging to distinct feeding guilds were sampled. None presented THg concentrations above the threshold levels of 0.5 µg g-1 established by the World Health Organization. However, biomagnification was observed (R = 0.8; p < 0.001), also confirmed by a trophic magnification factor of 1.76 for the entire food web. The THg content in the water was less than 0.001 mg L-1 and only Hemiodus unimaculatus presented seasonal variations for THg. Therefore, at the time of this study, the Xingu River presented low Hg contamination levels in both water and target fish.

Mercury and methyl mercury in fishes from Bacajá River (Brazilian Amazon): evidence for bioaccumulation and biomagnification.

This study assessed total mercury (THg) and methyl mercury (MeHg) concentrations, bioaccumulation and biomagnification of THg through the food web in fishes consumed by indigenous communities of Bacajá River, the largest tributary of the right bank of Xingu River. In total, 496 fish (22 species) were sampled. Nine species had THg concentrations above the limit recommended by the World Health Organisation (0·5 µg g(-1) wet mass), and one exceeded the recommended level for Hg in predatory fishes by Brazilian law (1·0 µg g(-1) ). The average concentration of THg increased significantly with trophic guild (herbivorous to piscivorous) and trophic level, with higher accumulation in fishes with greater total length. Ninety-six per cent of all mercury was methylated. These results suggest that feeding habits determine THg concentrations in fishes and that Hg elimination rate is slow during growth, which allows greater accumulation. These findings show that fishes in the Bacajá River contain high concentrations of THg and MeHg.

fMRI of the sensorimotor cortex in patients with traumatic brain injury after intensive rehabilitation.

For evaluating the patterns of brain activation in sensorimotor areas following motor rehabilitation, seven male patients diagnosed with TBI underwent an fMRI study before and after being subjected to motor rehabilitation. Six patients showed a reduction in the BOLD signal of their motor cortical areas during the second fMRI evaluation. A decrease in cerebellum activation was also observed in two patients. Newly activated areas, were observed in four patients after treatment. In addition, an increase in the activation of the supplementary motor area (SMA) following rehabilitation was observed in only one test subject. The findings show that motor rehabilitation in TBI patients produces a decrease in the BOLD signal for the sensorimotor areas that were activated prior to treatment. In addition, we observed the recruitment of different brain areas to compensate for functional loss due to TBI in line with the cortical reorganisation mechanism.

Gait analysis following treadmill training with body weight support versus conventional physical therapy: a prospective randomized controlled single blind study.

STUDY DESIGN: Single-blind randomized, controlled clinical study. OBJECTIVES: To evaluate, using kinematic gait analysis, the results obtained from gait training on a treadmill with body weight support versus those obtained with conventional gait training and physiotherapy. SETTING: Thirty patients with sequelae from traumatic incomplete spinal cord injuries at least 12 months earlier; patients were able to walk and were classified according to motor function as ASIA (American Spinal Injury Association) impairment scale C or D. METHODS: Patients were divided randomly into two groups of 15 patients by the drawing of opaque envelopes: group A (weight support) and group B (conventional). After an initial assessment, both groups underwent 30 sessions of gait training. Sessions occurred twice a week, lasted for 30 min each and continued for four months. All of the patients were evaluated by a single blinded examiner using movement analysis to measure angular and linear kinematic gait parameters. Six patients (three from group A and three from group B) were excluded because they attended fewer than 85% of the training sessions. RESULTS: There were no statistically significant differences in intra-group comparisons among the spatial-temporal variables in group B. In group A, the following significant differences in the studied spatial-temporal variables were observed: increases in velocity, distance, cadence, step length, swing phase and gait cycle duration, in addition to a reduction in stance phase. There were also no significant differences in intra-group comparisons among the angular variables in group B. However, group A achieved significant improvements in maximum hip extension and plantar flexion during stance. CONCLUSION: Gait training with body weight support was more effective than conventional physiotherapy for improving the spatial-temporal and kinematic gait parameters among patients with incomplete spinal cord injuries.

The consumption of shark meat in the Amazon region and its implications for human health and the marine ecosystem.

Here, we evaluated the levels of As, Hg, Pb, and Cd in shark meat sold along the Amazon Coast of Brazil and used nitrogen stable isotope values to determine trophic position and to assess element biomagnification. From market samples, a total of 13 species were identified via molecular analysis, including those listed as endangered and vulnerable by the IUCN Red List. Arsenic was present in significantly higher concentrations than all other elements, followed by Hg, with the highest mean concentrations recorded in M. higmani (As: 19.46 ± 8.79 µg/g ww) and C. acronotus (Hg: 1.12 ± 0.68 µg/g ww). Lead and Cd were recorded at much lower levels in all species. The EWI of individual elements were above PTWI for all species when considering Hg, seven species for inorganic arsenic (iAs), and one species for Pb. The weekly consumption of 10 species should be reduced to less than 416.39 g, which is equivalent to the daily estimated fish consumption rate in the region. The mean (±SD) δ15N values of species ranged from 10.7 ± 0.51‰ in M. higmani to 14.2 ± 0.59‰ in C. porosus, indicating feeding over >1 trophic level. Arsenic was negatively correlated with δ15N values, while Hg was positively correlated indicating biodilution and biomagnification, respectively. Our results indicate that the sale and consumption of shark meat will expose consumers to potentially harmful levels of iAs and Hg, as well as contributing to the population decline of species including those that are currently categorized as threatened.

Heavy metals in the bottom sediments of the Furo of Laura estuary, Eastern Amazon, Brazil.

The Furo of Laura is an economically important river in the Amazon estuary. Thus, in the present study, we evaluated the metal distribution (Al, Cd, Co, Cu, Cr, Fe, Ni, and Mg) in the bottom sediments of this river. The sediments were sampled at four points every 2months for a year with an Ekman-Birge sampler. After microwave acid digestion, the metal levels were determined by optical emission spectrometry with inductively coupled plasma. The particle size and organic matter content influenced the concentration of the metals. The sediments were not enriched by the analyzed metals; the estuary therefore retained the characteristics of an uncontaminated environment, thus serving as a reference environment for comparison.

Mercury concentration in different tissues of Podocnemis unifilis (Troschel, 1848) (Podocnemididae: Testudines) from the lower Xingu River - Amazonian, Brazil.

Studies using chelonians as biosentinels of environment quality or health risks associated with turtle consumption are very rare, especially in the Amazon basin. This study aims to measure Mercury levels (Hg) in muscle, liver, fat and blood of Podocnemis unifilis from the lower Xingu River, assessing the possible difference in concentration between sexes and also evaluating the potential bioaccumulation along different body sizes. Samples were collected during the dry season (October 2012) and Mercury (Hg) concentrations were analysed by Cold Vapor Atomic Absorption Spectrometry (CVAAS). A total of 29 specimens of P. unifilis of different sizes showed low levels lower than 0.2 mg/Kg). Higher Hg concentrations were found in the liver, and significant correlations between Hg concentrations in the different tissues were also detected. There was no difference between males and females and a negative correlation was found between Hg concentration and body size.

Mercury concentration in different tissues of Podocnemis unifilis (Troschel, 1848) (Podocnemididae: Testudines) from the lower Xingu River – Amazonian, Brazil / Concentrações de mercúrio em diferentes tecidos de Podocnemis unifilis (Podocnemididae: Testudines) do baixo Rio Xingu – Amazônia, Brasil

Studies using chelonians as biosentinels of environment quality or health risks associated with turtle consumption are very rare, especially in the Amazon basin. This study aims to measure Mercury levels (Hg) in muscle, liver, fat and blood of Podocnemis unifilis from the lower Xingu River, assessing the possible difference in concentration between sexes and also evaluating the potential bioaccumulation along different body sizes. Samples were collected during the dry season (October 2012) and Mercury (Hg) concentrations were analysed by Cold Vapor Atomic Absorption Spectrometry (CVAAS). A total of 29 specimens of P. unifilis of different sizes showed low levels lower than 0.2 mg/Kg). Higher Hg concentrations were found in the liver, and significant correlations between Hg concentrations in the different tissues were also detected. There was no difference between males and females and a negative correlation was found between Hg concentration and body size.

Estudos utilizando quelônios como biosentinelas de qualidade ambiental ou de riscos à saúde associados ao consumo de tartarugas são raros, especialmente na bacia amazônica. Neste estudo foram medidos os níveis de mercúrio no músculo, fígado, gordura e sangue de Podocnemis unifilis do baixo Rio Xingu. Foram avaliadas as possíveis diferenças de concentração entre os sexos e também o potencial de bioacumulação ao longo de diferentes tamanhos corporais. A etapa de amostragem ocorreu durante o período seco (Outubro de 2012) e a quantificação de Mercúrio (Hg) foi realizada através de digestão ácida e análises por Espectrometria de Absorção Atômica com Vapor Frio (CVAAS). Um total de 29 amostras de Podocnemis unifilis, mesmo em diferentes tamanhos, mostraram concentrações de Hg menores que 0,2 mg/kg. As concentrações mais elevadas de Hg foram encontradas no fígado, e também foram detectadas correlações significativas entre as concentrações de Hg nos tecidos. Não foram observadas diferenças significativas entre machos e fêmeas, sendo registrada correlação negativa entre a concentração de Hg e o tamanho do corpo.

[Gait analysis and quality of life evaluation after gait training in patients with spinal cord injury]. / Analisis de la marcha y evaluación de la calidad de vida después del entrenamiento de la marcha en pacientes con lesion medular.

INTRODUCTION: Over recent years it has become possible to retrain motor activity among patients with partial spinal cord injury, especially for walking. AIM. To assess the impact of gait training on a treadmill with body weight support, regarding temporospatial parameters and quality of life. PATIENTS AND METHODS: Twelve patients of both sexes were evaluated. They had been diagnosed with partial spinal cord injury of traumatic origin at least 12 months earlier. They were able to walk and their motor function below the level of the injury was partially preserved and classified as level C or D. After the initial evaluation, the participants were trained on a treadmill with body weight support, with two sessions per week lasting 30 minutes each, over a four-month period, thus totaling 30 sessions. The patients' temporospatial gait parameters and quality of life were analyzed before and after the training. RESULTS: There were improvements in all the temporospatial parameters evaluated (p < 0.0001), but no changes in quality of life were seen (p > 0.05). CONCLUSION: Treadmill training with body weight support among patients with spinal cord injury was effective in improving the temporospatial gait parameters, but without changing their quality of life.

[Effect of neuromuscular electrical stimulation and isotonic exercises in flexor and extensor muscles of knee of hemiplegic patients]. / Efecto de la estimulación eléctrica neuromuscular y de los ejercicios isotónicos en los músculos flexores y extensores de la rodilla en pacientes hémiplejicos.

AIM: To verify the muscular force and resistance to the movement of the flexor and extensor muscles of the knee of patients with spasticity after treatment with neuromuscular electrical stimulation (NMES) and isotonic exercises. PATIENTS AND METHODS: The patients this study were divided into group 1 (NMES) and group 2 (isotonic exercises). Their muscular torque and resistance to the movement of the flexor and extensor knee muscles were measured by the isokinetic dynamometer and the degree of spasticity by the modified Ashworth scale before and after ten sessions. RESULTS: Alterations in the scores of the modified Ashworth scale were not observed. An increase in the flexor torque in group 1 (p = 0.041) and in group 2 (p = 0.001) was verified. In the passive mode, group 1 presented a reduction of resistance to the flexion movement (p = 0.026), while in group 2, a reduction of resistance to both the flexion (p = 0,029) and extension movements (p = 0.019) was verified. CONCLUSIONS: The two therapeutical resources had their efficiency proven only for the increase of the force of the flexor muscles. The resistance to movement, the isotonic exercises were more effective because they promoted a reduction in the resistance of the flexor and extensor knee muscles.

A contribution to the establishment of reference values for total mercury levels in hair and fish in amazonia.

Studies on mercury levels in the Amazonian Region have typically lacked background or reference parameters. A sectional study on Hg concentration in hair and fish was conducted, together with an assessment of the prevalence of signs and symptoms related to Hg poisoning, in four communities in the Amazon Basin not impacted by gold mining, located either by a river course (Santana do Ituqui and Caxiuanã) or by a lake (Aldeia do Lago Grande and Vila do Tabatinga). Mercury determinations in hair and fish were made by flameless atomic absorption spectrophotometry. Mean total Hg in hair was 4.33 microg/g (0.40-11.60 microg/g) in 321 individuals from Santana do Ituqui, 3.98 microg/g (0.40-11.76 microg/g) for 316 persons in Aldeia do Lago Grande, 5.46 microg/g (0.37-49.85 microg/g) for 504 individuals from Vila do Tabatinga and 8.58 microg/g (0.61-45.59 microg/g) for 203 inhabitants from Caxiuanã. Fish consumption was very high in all those communities but no signs or symptoms associated with Hg poisoning were found. Mean Hg concentration in fish varied from 0.006 to 2.529 microg/g for carnivores and from 0.008 to 0.871 microg/g for noncarnivores. These values suggest that further studies including a larger number of communities would eventually lead to values of "normal" Hg concentration in the Amazonian Region quite above the limits suggested by the World Health Organization.