HIV-1 Tat alters neuronal intrinsic excitability

Objective: In HIV+ individuals, the virus enters the central nervous system and invades innate immune cells, producing important changes that result in neurological deficits. We aimed to determine whether HIV plays a direct role in neuronal excitability. Of the HIV peptides, Tat is secreted and acts in other cells. In order to examine whether the HIV Tat can modify neuronal excitability, we exposed primary murine hippocampal neurons to that peptide, and tested its effects on the intrinsic membrane properties, 4 and 24 h after exposure. Results: The exposure of hippocampal pyramidal neurons to Tat for 4 h did not alter intrinsic membrane properties. However, we found a strong increase in intrinsic excitability, characterized by increase of the slope (Gain) of the input-output function, in cells treated with Tat for 24 h. Nevertheless, Tat treatment for 24 h did not alter the resting membrane potential, input resistance, rheobase and action potential threshold. Thus, neuronal adaptability to Tat exposure for 24 h is not applicable to basic neuronal properties. A restricted but significant effect on coupling the inputs to the outputs may have implications to our knowledge of Tat biophysical firing capability, and its involvement in neuronal hyperexcitability in neuroHIV

Programa de pesquisas da Embrapa Amazônia Oriental para o melhoramento genético de búfalos.

bitstream/item/18919/1/Doc-303.pdfVersão eletrônica. 1ª impressão: 2009

Derek Denny-brown: The Man Behind The Ganglia

The authors present an historical review about the main contributions of Professor Derek Denny-Brown to neurology. Some of his achievements include the first description of sensory neuronopathies, and some of the essential textbooks on the function and anatomy of the basal ganglia. In 2016, on the 35th anniversary of his death, modern neurologists are still strongly influenced by his legacy.75212712

Utilização de chuveiros na sala pré-ordenha e sua influência na produtividade de búfalas da raça Murrah (Bubalus bubalis).

O estudo foi realizado com 64 búfalas, em dois tratamentos (1 e 2), durante seis dias. No primeiro, antes da ordenha, os animais permaneceram 1h em sala de espera com acesso ao chuveiro No segundo, os animais não tiveram acesso ao chuveiro. Foram registrados Índice de Temperatura de Globo e Umidade (ITGU) e a Umidade Relativa (UR) das salas de ordenha e de espera, Temperatura de Corpo (TC), Frequência Respiratória (FR), Reatividade (REAT), Nível de Estresse (NEST) e a Produção Diária de Leite (PL). Os dados foram analisados com o auxílio do programa SAS. O efeito da FR não foi significativo (P>0,57) sobre a PL. Não houve diferença significativa na PL para a REAT. O NEST foi o mesmo nos dois tratamentos. As regressões da característica (PL_AJ) sobre ITGU Interno (ITGU_I), ITGU Externo (ITGU_E), TC e UR não foram significativas (P>0,12). No tratamento 2 foram observados maior número de animais em classes de estresse, verificou-se que o tratamento 1 possibilitou a mudança ( alguns animais) da zona de alerta ou estresse para a zona de conforto térmico em relação ao ITGU_I. No tratamento 2, todos os animais estavam em estresse térmico. Os animais submetidos ao estresse calórico em ambas as situações utilizaram com eficiência o seu sistema termorregulador, sem interferir na produção de leite

Genetic structuring and fixed polymorphisms in the gene period among natural populations of Lutzomyia longipalpis in Brazil

Citation: Costa, C. R. L., Freitas, M. T. D., Figueiredo, C. A. S., Aragao, N. C., da Silva, L. G., Marcondes, C. B., . . . Balbino, V. D. (2015). Genetic structuring and fixed polymorphisms in the gene period among natural populations of Lutzomyia longipalpis in Brazil. Parasites & Vectors, 8, 9. doi:10.1186/s13071-015-0785-6Background: Even one hundred years after being originally identified, aspects of the taxonomy of the sand fly Lutzomyia longipalpis, the principal vector of Leishmania infantum in the Americas, remain unresolved for Brazilian populations of this vector. The diversity of morphological, behavioral, biochemical, and ethological characters, as well as the genetic variability detected by molecular markers are indicative of the presence of a complex of species. Methods: In this study, a 525 bp fragment of the period gene was used to evaluate sympatric populations of L. longipalpis. A combination of probabilistic methods such as maximum likelihood and genetic assignment approach to investigate sympatric species of L. longipalpis were applied in three populations of Northeast Brazil. Results: Fixed polymorphisms in geographically isolated populations of L. longipalpis from two localities in the state of Ceara and one in the state of Pernambuco, Brazil, was identified in a 525 bp fragment of the gene period (per). Our results suggest a direct relationship between the number of spots found in males' tergites and the genetic variation in cryptic species of L. longipalpis. The fragment used in this study revealed the nature of the ancestral morphotype 1S. Conclusion: New polymorphisms were identified in the gene per which can be used as a genetic barcode to sympatric taxonomy of L. longipalpis. The per gene fragment confirmed the presence of two siblings species of L. longipalpis in Sobral and showed that these same species are present in two other localities, representing an expansion within the L. longipalpis species complex with regards to the states of Ceara and Pernambuco