Effect of Anodal Transcranial Direct Current Stimulation over the Motor Cortex for Cognition

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that modulates cortical excitability and influences cognition. The role of the primary motor cortex (M1) in cognition is controversial. Here, we investigated the offline effects of anodal and sham tDCS over M1 on cognitive tasks that require comparable motor skills, but different levels of working memory and attention. Twenty healthy young female adults received anodal tDCS and sham tDCS to the M1 on two separate testing days in a counter balanced order. The cognitive functions outcome variables were the response time from the Attention Switching Task (AST) and Motor Screening Task (MST) tests using the Cambridge Neuropsychological Test Automated Battery before and after the anodal/sham tDCS. Anodal tDCS significantly improved AST response times from baseline in congruent and incongruent condition and MST mean correct latency (all p < 0.05). There was a significant difference for AST tasks variable include AST Switching cost (mean, correct), AST Mean correct latency, in congruent, incongruent, blocks 3, 5 (non-switching blocks), block 7 (switching block) (p < 0.01) and MST mean latency (p < 0.05) between anodal and sham conditions. These results indicate that tDCS is a promising tool to an improvement in response time in task related attention and motor speed. However, this study warrants further research to determine the long-term effect on other cognitive functions and in different age and gender groups.

Utilidad de la tomografía computarizada multidetector en la evaluación postoperatoria de cirugías de derivación urinaria / Usefulness of multidetector computed tomography in the postoperative evaluation of urinary diversion surgery

Las cirugías de derivación urinaria son procedimientos que cada vez son más frecuentes, ya que sus indicaciones no son sólo neoplásicas, siendo también útiles en el manejo de otras patologías. Debido a este incremento, no es infrecuente observar complicaciones secundarias, ya sean en el postoperatorio temprano (menos de 30 días después de la cirugía) o tardío (más de 30 días). Dentro de éstas tenemos alteraciones de la motilidad intestinal (íleo paralítico, obstrucción), fugas anastomóticas, colecciones líquidas (linfocele, urinoma, absceso), fístulas, herniación paraestomal, estenosis ureterales, litiasis y recurrencia tumoral. Dada la gran cantidad de técnicas quirúrgicas usadas en estos procedimientos, es importante conocer los cambios anatómicos resultantes, ocasionalmente de difícil valoración. La tomografía computarizada multidetector (TCMD) tiene gran utilidad en el estudio de estos pacientes, especialmente mediante las técnicas de reconstrucción multiplanar, representando adecuadamente las estructuras urinarias y extraurinarias afectadas, y sus relaciones con estructuras adyacentes, permitiendo identificarlas acertada y rápidamente.

Urinary diversion surgeries are procedures that are becoming more frequent, as their indications are not only neoplastic, being useful also in managing other diseases. Due to this increase, it is not uncommon to observe secondary complications, whether in the early postoperative period (less than 30 days after surgery) or later (more than 30 days). Within these are alterations in intestinal motility (paralytic ileus, blockage), anastomotic leaks, fluid collections (lymphocele, urinoma, abscess), fistulas, parastomal herniation, ureteral obstruction, urolithiasis and tumor recurrence. Given the large number of surgical techniques used in these procedures, it is important to know the resulting anatomical changes, occasionally difficult to evaluate. Multidetector computed tomography (MDCT) is of great use in the study of these patients, especially with multiplanar reconstruction techniques, adequately representing the affected urinary and extra-urinary structures, and their relationship to adjacent structures, enabling their accurate and quick identification.

Genetic diversity and evidence of recent demographic expansion in waterbird populations from the Brazilian Pantanal

The present study determined nuclear and mitochondrial (mtDNA) levels of genetic variability and phylogeographic patterns in breeding populations of Roseate Spoonbill (N = 57), Wood Stork (N = 89), and Jabiru Stork (N = 30), sampled in the Brazilian Pantanal. These species were selected since they are bioindicators of wetlands’ health and are threatened in other parts of their distribution. As they are in close association with this ecosystem, they are appropriate for studying the effects of Pleistocene climatic changes on their demographic patterns. Levels of nuclear genetic diversity in Pantanal populations were not significantly different from those of other populations throughout the American continent, where they are considered threatened or of special concern. Reduced levels of mtDNA genetic diversity were observed in the Central American population of Jabiru Stork in comparison to the Pantanal population. Recent demographic expansion in the Pantanal was markedly evidenced by unimodal patterns of mismatch distribution and Fu’s Fs neutrality test in these three species. We hypothesize that the average time of population expansion (between 30,843 and 14,233 years before present) is associated to responses of these birds’ populations to paleoclimatic changes in these wetlands during the last glaciation period. We recommend special conservation efforts with the Jabiru Stork populations, a genetic monitoring program based on mtDNA, and an ecological characterization of these waterbirds species throughout their distribution range.

O presente estudo determinou níveis de variabilidade nuclear e mitocondrial (DNAmit) e padrões filogeográficos de populações reprodutivas de colhereiro (N = 57), cabeça-seca (N = 89) e tuiuiú (N = 30) do Pantanal brasileiro. Estas espécies foram selecionadas porque são bioindicadoras da integridade das áreas alagáveis e se encontram ameaçadas em outras partes da sua área de distribuição. Devido à sua estreita associação com esse tipo de ecossistema, seu estudo permite verificar os efeitos das mudanças climáticas do Pleistoceno nos seus padrões demográficos. Níveis de diversidade genética nuclear nas populações pantaneiras não diferiram significativamente dos encontrados em outras populações ao longo do continente americano onde são consideradas ameaçadas ou como de especial interesse para conservação. Níveis reduzidos de variabilidade genética DNAmit foram observados nas populações de tuiuiú da América Central, quando comparadas às populações do Pantanal. A expansão demográfica recente das três espécies no Pantanal ficou marcadamente evidenciada pelos padrões unimodais da distribuição das diferenças pareadas e pelo teste de neutralidade de Fs de Fu. Hipotetizamos que o tempo médio de expansão populacional (entre 30.843 e 14.233 anos antes do presente) está associado as respostas destas populações de aves às mudanças climáticas ocorridas nas áreas alagáveis durante o último período de glaciação. Recomendamos, esforços especiais na conservação das populações do tuiuiú, um programa de monitoramento genético baseado no DNAmit e a caracterização ecológica dessas espécies de aves aquáticas ao longo de suas áreas de distribuição.

Genetic variability in three Amazon parrot species

Parrots of the genus Amazona are among the most threatened species of the Order Pscittaciformes. This work describes allozyme polymorphisms in three Amazon parrot species - the Blue-fronted Amazon (Amazona aestiva), the Orange-winged Amazon (Amazona amazonica), and the Festive Amazon (Amazona festiva) -, and provides useful data for the evaluation of their genetic variability. We electrophoretically analyzed blood samples from 68 wild-caught individuals, maintained in captivity in three Brazilian zoos. Eight of the ten studied enzyme loci exhibited polymorphism. Glucosephosphate isomerase (Gpi) proved to be a diagnostic locus for the identification of these Amazon species. The expected average heterozygosity of the Blue-fronted Amazon (0.060) differed significantly from the expected heterozygosities of the Orange-winged Amazon and the Festive Amazon (0.040 and 0.039, respectively). This result was discussed as a consequence of hybridization between two geographic A. aestiva subspecies, and alternatively as a particular trait of this species. Genetic variability of the Blue-fronted Amazon compared to birds in general is not low on a species-wide level, despite the fact that this parrot is one of the most illegally traded species. Allozyme analysis proved to be an useful tool in monitoring the genetic variation within the genus Amazona and can be applied in the management program of other threatened species of this genus.

Papagaios do gênero Amazona estão entre as espécies mais ameaçadas da Ordem Psittaciformes. O presente trabalho descreve polimorfismos enzimáticos em três espécies de papagaios do gênero Amazona: o papagaio verdadeiro (Amazona aestiva), o papagaio do mangue (Amazona amazonica) e o papa-cacau (Amazona festiva). Estes dados foram utilizados para avaliação da variabilidade genética dessas espécies. Foram analisadas, através de eletroforese, amostras de sangue de 68 indivíduos capturados na natureza e mantidos em cativeiro em três zoológicos brasileiros. Oito dentre dez locos enzimáticos analisados exibiram polimorfismo. O loco da Glicose Fosfato Isomerase (Gpi) demonstrou ser um loco diagnóstico para a identificação dessas espécies de papagaios. A heterozigosidade média esperada para A. aestiva (0,060) diferiu significativamente das heterozigosidades esperadas para A. amazonica e A. festiva (0,042 e 0,039, respectivamente). Este resultado foi discutido como uma conseqüência de hibridização entre duas subespécies geográficas de A. aestiva e, alternativamente, como uma característica particular da espécie. Comparada a aves em geral, a variabilidade genética de A. aestiva não é baixa, apesar deste papagaio ser uma das espécies mais comercializadas ilegalmente. A análise alozímica demonstrou ser uma ferramenta útil para o monitoramento da variabilidade genética do gênero Amazona, podendo ser aplicada em programas de manejo destas e de outras espécies ameaçadas pertencentes ao mesmo gênero.

Genetic structure in Brazilian breeding colonies of the Roseate Spoonbill (Platalea ajaja, Aves: Threskiornithidae)

Roseate Spoonbills (Platalea ajaja, Linnaeus) are wading birds present in two of the most important Brazilian wetlands: the Pantanal wetlands and Rio Grande do Sul marshes. Natural populations of these species have not been previously studied with variable nuclear molecular markers. In order to support decision making regarding the management and conservation of these populations, we estimated and characterized the distribution of genetic variability among five Brazilian breeding colonies. The average observed heterozygosity in Brazilian Roseate Spoonbill populations (Ho = 0.575) did not differ significantly from the value determined in a U.S. wild-caught sample of 15 individuals, using data generated by the same set of microsatellite loci. Considering that the U.S. population underwent a recent reduction in size, we discuss this result supposing that the U.S. population was not genetically affected or that both populations had suffered a bottleneck. Global F(ST) indicated the lack of genetic differentiation among colonies, indicating the occurrence of past and/or present gene flow among them. Analysis of molecular variance revealed that most of the genetic variation is distributed within the colonies. Results are explained by a recent origin of colonies or by high levels of gene flow. Management decisions should take into consideration the fact that, even in the presence of high genetic exchange, ecological adaptations to different environments are important for species survival.

Hexokinase polymorphism in Apis mellifera and its use for africanized honeybee identification

Neste trabalho é descrito o alto grau de polimorfismo da hexoquinase (HK) em abelhas africanizadas do Brasil e confirmado o monomorfismo deste sistema em abelhas de origem européia. A detecçäo da alozima 87 em abelhas africanizadas do Brasil é explicada pela introduçäo de Apis mellifera scutellata no país em 1956. A frequência do gene HK nas populaçöes brasileiras analisadas é maior em Luiz Antonio, Estado de Säo Paulo, localidade próxima a Rio Claro, centro inicial de dispersäo dos enxames africanos. A frequência deste alelo diminui à medida que populaçöes situadas a uma maior distância deste centro säo amostradas, particularmente, em áreas mais ao sul do país, onde a atividade apícola com base em abelhas européias foi mais intensa. A detecçäo deste polimorfismo se reveste de significativa importância para o rastreamento de genes africanos em populaçöes de Apis mellifera existentes no continente americano