The silent period in patients with chronic renal failure undergoing hemodialysis

Silent period was evaluated in 20 adult male patients with chronic renal failure undergoing hemodialysis. Readings were obtained by supramaximal stimulus to the median nerve, during maximum isometric effort of the abductor pollicis brevis muscle against resistance. Two types of abnormalities were observed, motor neuron hypoexcitability with elongated silent period, and motor neuron hyperexcitability with reduction or absence of silent period. Some abnormalities are probably linked with dialysis duration, but show no correlation to presence or absence of peripheral neuropathy. The silent period alterations described in this study could possibly correlate with some other clinical feature frequently seen in patients with chronic renal failure such as hypereflexia of the deep tendon reflexes.

Video target tracking by using competitive neural networks

A target tracking algorithm able to identify the position and to pursuit moving targets in video digital sequences is proposed in this paper. The proposed approach aims to track moving targets inside the vision field of a digital camera. The position and trajectory of the target are identified by using a neural network presenting competitive learning technique. The winning neuron is trained to approximate to the target and, then, pursuit it. A digital camera provides a sequence of images and the algorithm process those frames in real time tracking the moving target. The algorithm is performed both with black and white and multi-colored images to simulate real world situations. Results show the effectiveness of the proposed algorithm, since the neurons tracked the moving targets even if there is no pre-processing image analysis. Single and multiple moving targets are followed in real time.

Post-ganglionic Horner's syndrome: An unusual presentation of non-Hodgkin lymphoma

In this paper, we present the rare case of a patient with cervical lymphadenopathy diagnosed as a T-cell-rich B-cell non-Hodgkin lymphoma that manifested Horner's syndrome due to a post-ganglionic sympathetic neuron lesion caused by the tumor. Copyright © 2012 S. Karger AG, Basel.

Alterations in the duodenum myenteric neurons of Wistar rats after ingesting of 2,4 dichlorophenoxyacetic acid

The 2,4 dichlorophenoxyacetic acid (2,4-D) is a systemic herbicide whose effects in animal organic systems have been examined in previous studies, being the neurotoxicity considered the predominant effect. However, the studies that detect the 2,4-D neurotoxicity have merely focused in the central nervous system, and therefore, little is known about the effect of this herbicide in the enteric nervous system. This study aimed to verifying the 2,4-D effects on the myenteric neurons in duodenum of Wistar rats. Ten 60-day-old male Wistar rats (Rattus norvegicus) were divided in two groups: control group (C) that did not receive 2,4-D and experimental group (E) that received 5.0 mg of 2,4-D/kg for 15 days. At the end of experimental period, the animal were euthanized, the duodenum was collected and processed for NADPH-diaphorase histochemical analysis in order to expose the nitrergic myenteric neurons (NADPH-dp). In the light microscopy analysis, the whole-mount preparation obtained from duodenum of each animal were image-captured in 120 and 40 fields, for quantitative and morphometric analyses of myenteric neurons, respectively. The neuronal density was not affected when comparing the two groups, but an increase (p > 0.05) of 8.5% was observed in the cell body area of neurons in the E group. In conclusion, the ingestion of 2,4-D at a dosage of 5.0 mg/kg body weight for 15 days does not change the neuronal density, but promotes the hypertrophy of NADPH-dp myenteric neurons in duodenum of the rats of this study.

Naturalidade: o nível profundo da comunicaçao

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise da estabilidade transitória via rede neural Art-Artmap fuzzy Euclidiana modificada com treinamento continuado

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Intoxicação experimental por Ipomoea asarifolia em ovinos: achados clínicos, laboratoriais e anatomopatológicos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Projeto e implementação de redes neurais artificiais em distintos níveis de abstrações para o reconhecimento de deficiências de diversos macronutrientes e cultivares

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Intrinsic organization of the suprachiasmatic nucleus in the capuchin monkey

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A NEURAL NET FOR EXTRACTING KNOWLEDGE FROM NATURAL-LANGUAGE DATA-BASES

The present paper introduces a new model of fuzzy neuron, one which increases the computational power of the artificial neuron, turning it also into a symbolic processing device. This model proposes the synapsis to be symbolically and numerically defined, by means of the assignment of tokens to the presynaptic and postsynaptic neurons. The matching or concatenation compatibility between these tokens is used to decided about the possible connections among neurons of a given net. The strength of the compatible synapsis is made dependent on the amount of the available presynaptic and post synaptic tokens. The symbolic and numeric processing capacity of the new fuzzy neuron is used here to build a neural net (JARGON) to disclose the existing knowledge in natural language data bases such as medical files, set of interviews, and reports about engineering operations.

Efeitos de relevância versus repetição de estímulo lingüístico na indução da memória declarativa

In the LTP (Long-Term Potentiation) model of learning and memory formation, elaborated in the context of molecular neurobiology, the opening of NMDA (N-Metyl-D-Aspartate) channels to entry of calcium ions into the post-synaptic neuron depends on two excitatory events: the repeated activation of the post-synaptic neuron by only one pre-synaptic neuron (Alternative 1), or its concomitant activation by two or more pre-synaptic neurons (Alternative 2). With the purpose of testing these alternatives, in the context of Cognitive Psychology, we presented to 73 university students a sequence of slides, with the duration of 6 seconds each, containing sentences (one for each slide) considered as being relevant or irrelevant for the subjects. Relevant sentences (R1) were presented only one time, while irrelevant ones were divided in three groups: the first one with sentences presented only one time (I1), the second with sentences presented three times (I3) and the third with sentences presented five times (I5). We conjectured that relevant sentences presented only one time would mobilize two or more brain excitatory pathways (corresponding to Alternative 2 above), while repeated irrelevant sentences would progressively activate the same sensory pathway. After the presentation of the sentences, the subjects answered a written questionnaire with questions about each presented sentence. The results indicate a prevalence of correct answers to R1 over I1, I3 and I5, suggesting that the relevance factor has greater weight than repetition in the induction of declarative memories

Caracterização e infecção de células tronco mesenquimais e células semelhantes a neurônios, derivadas de cordão umbilical bovino pelo herpesvírus bovino Tipo 5 (BoHV-5)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Toxoplasmosis: morphological and morphometric evaluation of spinal cord neurons from nonsymptomatic seropositive dogs

The aim of this work was to analyze the neuron morphology and morphometry of cervical, thoracic and lumbar areas of nonsymptomatic seropositive dogs’ spinal cord for toxoplasmosis. Twenty indefinite-breed adult dogs were used; ten dogs were healthy, with negative serology for toxoplasmosis, and were used as the control group (group 1), and ten dogs were nonsymptomatic but seropositive for toxoplasmosis (group 2). After the microtomy, with interval of 100 micrometers (µm), the histological 5-µm-thick cuts were dyed by hematoxylin-eosin and Masson's trichrome techniques. The glass slides were analyzed under light microscope to examine the neuron morphology. The parameters considered for the morphometric analysis were area, perimeter, maximum diameter, minimum diameter and shape factor of cytoplasm and nucleus of neuron. The results were statistically analyzed by Student’s t test at 5% probability level. The morphological characteristics between the two groups were similar and according to literature. The morphometric results showed that there were changes in neurons size and structure, and increase and loss of star shape were noticed in seropositive animals. The results suggest that the neurons of these dogs, yet nonsymptomatic, can have lost their conductor function.