RESUMO
Studies have shown cases of poisoning with plants from the genus Crotalaria (Leguminosae) mainly in animals. They induce damages in the central nervous system (CNS), which has been attributed to toxic effects of the pyrrolizidine alkaloid (PA) monocrotaline (MCT). Previously we demonstrated that both MCT and dehydromonocrotaline (DHMC), its main active metabolite, induce changes in the levels and patterns of expression of the main protein from astrocyte cytoskeleton, glial fibrillary acidic protein (GFAP). In this study we investigated the effect of MCT on rat cortical astrocyte/neuron primary co-cultures. Primary cultures were exposed to 10 or 100 µM MCT. The MTT test and the measurement of LDH activity on the culture medium revealed that after 24h exposure MCT was not cytotoxic to neuron/astrocyte cells. However, the cell viability after 72 h treatment decreased in 10-20%, and the LDH levels in the culture medium increased at a rate of 12% and 23%, in cultures exposed to 10 or 100 µM MCT. Rosenfeld staining showed vacuolization and increase in cell body in astrocytes after MCT exposure. Immunocytochemistry and Western blot analyses revealed changes on pattern of GFAP and ßIII-tubulin expression and steady state levels after MCT treatment, with a dose and time dependent intense down regulation and depolarization of neuronal ßIII-tubulin. Moreover, treatment with 100 µM MCT for 12h induced GSH depletion, which was not seen when cytochrome P450 enzyme system was inhibited indicating that it is involved in MCT induced cytotoxicity in CNS cells.
Assuntos
Astrócitos/efeitos dos fármacos , Cérebro/efeitos dos fármacos , Crotalaria , Monocrotalina/toxicidade , Neurônios/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Astrócitos/metabolismo , Astrócitos/patologia , Western Blotting , Forma Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Cérebro/embriologia , Cérebro/metabolismo , Cérebro/patologia , Técnicas de Cocultura , Crotalaria/química , Inibidores das Enzimas do Citocromo P-450 , Sistema Enzimático do Citocromo P-450/metabolismo , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Proteína Glial Fibrilar Ácida/metabolismo , Glutationa/metabolismo , Imuno-Histoquímica , L-Lactato Desidrogenase/metabolismo , Monocrotalina/isolamento & purificação , Neurônios/metabolismo , Neurônios/patologia , Ratos , Ratos Wistar , Fatores de Tempo , Tubulina (Proteína)/metabolismoRESUMO
The mammalian subventricular zone (SVZ) contains progenitors derived from cerebral cortex radial glia cells, which give rise to glutamatergic pyramidal neurons during embryogenesis. However, during postnatal life, SVZ generates neurons that migrate and differentiate into olfactory bulb γ-aminobutyric acid (GABA)ergic interneurons. In this work, we tested if SVZ cells are able to produce glutamatergic neurons if confronted with the embryonic cortical ventricular zone environment. Different from typical SVZ chain migration, cells from P9-P11 SVZ explants migrate into embryonic cortical slices individually, many of which radially oriented. An average of 82.5% of green fluorescent protein-positive cells were immunolabeled for neuronal marker class III ß-tubulin. Invading cells differentiate into multiple morphologies, including a pyramidal-like morphotype. A subset of these cells are GABAergic; however, about 28% of SVZ-derived cells are immunoreactive for glutamate. Adult SVZ explants also give rise to glutamatergic neurons in these conditions. Taken together, our results indicate that SVZ can be a source of glutamatergic cortical neurons when submitted to proper environmental cues.
Assuntos
Cérebro/citologia , Cérebro/embriologia , Ácido Glutâmico/fisiologia , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Neurogênese/fisiologia , Células Piramidais/citologia , Células Piramidais/metabolismo , Animais , Animais Recém-Nascidos , Diferenciação Celular/fisiologia , Células Cultivadas , Cérebro/crescimento & desenvolvimento , Técnicas de Cocultura , Camundongos , Camundongos Transgênicos , Técnicas de Cultura de ÓrgãosRESUMO
OBJECTIVE: To compare sonographic visualization of midline cerebral structures obtained by two-dimensional (2D) imaging and three-dimensional (3D) multiplanar and volume contrast imaging in the coronal plane (VCI-C), with transfrontal 3D acquisition. METHODS: Sixty consecutive healthy fetuses in vertex presentation at a mean gestational age of 24 (range, 20-33) weeks underwent 2D and 3D ultrasound examination. Sagittal cerebral planes were reconstructed using 3D acquisition from axial planes by multiplanar analysis and by VCI-C. The reconstructed midline images of both these techniques were compared with the midline structures visualized directly in the A-plane by transfrontal 3D acquisition using a sweep angle of 30 degrees . Measurement of the corpus callosum and cerebellar vermis and visualization of the fourth ventricle and the main vermian fissures were compared. The sharpness of the images was also assessed qualitatively. Mid-sagittal tomographic ultrasound imaging (TUI) was also performed. 3D planes were compared with 2D transfontanelle median planes obtained by transabdominal or, when required, transvaginal sonography. RESULTS: The midline plane could be obtained in 88% of multiplanar, 82% of VCI-C and 87% of transfrontal analyses. Measurements of the corpus callosum and cerebellar vermis obtained by 3D median planes were highly correlated. The clearest and sharpest definition of midline structures was obtained with transfrontal acquisition. Primary and secondary fissures of the cerebellar vermis could be detected in 13-26% of multiplanar, 18-35% of VCI-C and 52-79% of transfrontal analyses. 2D visualization was superior or equal to the 3D transfrontal approach in all the parameters compared. CONCLUSION: 3D planes obtained from axial acquisitions are simpler and easier to display than are transfrontal ones. However, artifacts and acoustic shadowing are frequent in 3D axial acquisition and spatial resolution is better in the direct visualization transfrontal technique. If the standard examination includes a view of the fetal facial profile, a quick 3D acquisition through the frontal sutures provides direct visualization for assessment of the midline structures. We believe that this volumetric methodology could represent a step towards incorporating a comprehensive fetal neuroscan into routine targeted organ evaluation.
Assuntos
Cérebro/diagnóstico por imagem , Cérebro/embriologia , Ecoencefalografia/métodos , Ultrassonografia Pré-Natal/métodos , Feminino , Idade Gestacional , Humanos , Processamento de Imagem Assistida por Computador , Imageamento Tridimensional , Gravidez , Segundo Trimestre da GravidezRESUMO
Nas concepçoes clássicas da Medicina Tradicional Chinesa, o Xin (Coraçao) representa um Zang (Orgao) de características bastante peculiares, com funçoes energéticas que o levam a ser descrito como "Imperador dos Zang (Orgaos)", exercendo influência sobre todos os outros Zang (Orgaos) e também controlando a atividade psíquica, a circulaçao de sangue e os vasos sangüíneos; expressa-se na língua e, para o seu equilíbrio energético, depende de um controle regulador do Shen (Rins). Sob enfoque da Medicina Ocidental, pode-se constatar, embriologicamente, que o coraçao mantém estreitas conexoes com os vasos sangüíneos, o encéfalo e a língua e, fisiologicamente, apresenta importante relaçao com os rins, intermediada pelo fator natriurético atrial. Estes aspectos da Medicina Ocidental, conforme sugerimos neste artigo, podem vir a constituir um suporte objetivo, que fundamente a abordagem filosófica que a Medicina Tradicional Chinesa dispensa a este tema.
Assuntos
Humanos , Acupuntura , Coração/embriologia , Coração/fisiologia , Cérebro/embriologia , Cérebro/fisiologia , Rim/fisiologia , Língua/embriologia , Língua/fisiologiaRESUMO
El presente estudio pretende analizar microscópicamente los defectos inducidos por el etanol cuando la exposición ocurre durante los primeros estadios de desarrollo en el pollo. En este estudio se emplearon huevos fecundados de gallina (White Leghorn). Los huevos fueron tratados con etanol en el día 0 (29, 40 y 60 por ciento) mediante instilación en la cámara de aire. El grupo control fue instilado con 0,1 ml de NaCI al 0,9 por ciento. Los huevos se incubaron a 37,8 ºC. Los embriones fueron extraídos, desde los huevos, después de 11 días de incubación y examinados con lupa esteroscópica. Las muestras obtenidas fueron fijadas en formol al 10 por ciento , fotografiadas y procesadas de acuerdo a las técnicas histológicas corrientes y por el método de picrosirius. El análisis microscópico por medio del método de picrosirius, reveló que el proceso de osificación membranosa presenta un menor desarrollo, además, una menor cantidad de colágeno tipo I en el hueso trabecular en los embriones postexposición a etanol con respecto al control
Assuntos
Animais , Embrião de Galinha , Embrião de Galinha/metabolismo , Etanol/farmacologia , Desenvolvimento Fetal/efeitos dos fármacos , Anormalidades Induzidas por Medicamentos , Cérebro/anormalidades , Cérebro/embriologia , Cérebro/metabolismo , Colágeno/deficiência , Grupos Controle , Embrião de Galinha , Instilação de Medicamentos , Microscopia , Malha Trabecular/anormalidades , Malha Trabecular/efeitos dos fármacosRESUMO
En tanto el encéfalo no pueda realizar cuando menos una de sus funciones básicas, el sistema sólo tendrá el potencial del funcionamiento encefálico del organismo humano. La definición tentaaativa del inicio de la vida encefálica humana es idéntica al inicio del aspecto operacional de éste sistema crítico. El uso del término "vida cerebral", es dificil de definir; sin embargo debe considerarse en el contexto de su capacidad estructural y funcional en su totalidad. La neurogénesis recapitula la ontogénia cerebral de la misma manera que la ontogénesis recapitula la filogénesis. En este trabajo se revisan los aspectos neurogenéticos y la ontogénesis del Sistema Nervioso.
Assuntos
Humanos , Medula Espinal/embriologia , Sistema Nervoso Central/anatomia & histologia , Cérebro/embriologia , Medula Espinal/fisiologia , Sistema Nervoso Central/embriologia , Desenvolvimento Fetal/fisiologia , Cérebro/fisiologiaRESUMO
El presente artículo presenta la descripción de un grupo de 22 pacientes en edad pediátrica, con trastornos de la migración neuronal estudiados en el Departamento Neuro Pediátrico del hospital Militar Central. Se enfatizan los hallazgos clínicos y se demuestra el valioso aporte de las imágenes diagnósticas para la identificación y clasificación de estas anomalías
Assuntos
Humanos , Gravidez , Recém-Nascido , Movimento Celular , Cérebro/anormalidades , Cérebro/embriologiaRESUMO
Las nuevas modalidades diagnósticas, y especialmente la Resonancia Magnética permiten diagnósticar con mayor frecuencia anormalidades de la migración neuronal y del surcado cerebral. Este artículo revisa gran parte de la literatura disponible y muestra ejemplos de éstas anormalidades, con énfasis en el diagnóstico imagenológico de las mismas
Assuntos
Humanos , Pré-Escolar , Lactente , Recém-Nascido , Cérebro , Cérebro/anormalidades , Cérebro/anatomia & histologia , Cérebro/embriologiaRESUMO
O crescimento do encéfalo foi estudado em 43 fetos humanos estagiados, usando o método alométrico ( Y = a Xb). Utilizando a correlaçao entre o peso do encéfalo (g) e os parâmetros fetais de crescimento: idade gestacional (spc) e perímetro cefálico (pc,mm). Os resultados mostram que o crescimento do encéfalo é alometricamente positivo no terceiro trimestre gestacional (b = 3,43 para spc e b = 3,88 para pc). Estes resultados sao importantes na determinaçao de anomalias congênitas do encéfalo e determinaçao da idade gestacional.
Assuntos
Humanos , Feminino , Gravidez , Cérebro/embriologia , Desenvolvimento Fetal , Terceiro Trimestre da Gravidez , Cérebro/crescimento & desenvolvimento , Idade Gestacional , Tamanho do ÓrgãoRESUMO
The existence and the morphological characteristics of pioneer axons in the anterior commissure (AC) were investigated in hamster embryos using fluorescent carbocyanine crystals implanted into the paleocortex. On embryonic days 12-13(E12-E13), a group of tortuous fibers was seen close to the midline. After this group of fibers reached the midline on E13.5-E14, pioneer axons were seen in the AC, and from E14.5 to E15.5 both pioneers and followers approached the targets, the former ahead of the latter by about 500 µm. Arborization took place as soon followers approached the targets, the former ahead of the latter by about 500 µm. Aarborization took place as soon as the followers reached the targets (E15.5-E16). The pioneer cells were labeled retrogradely and were seen in the most superficial layears of the paleocortex, along the rostrocaudal extent of the hemisphere. The fact that pionners appear only during or after crossing suggests the existence of factors either in the midline region and/or in the opposite hemisphere, which selectively accelerate the growth of the pioneers or decelerate the growth of the followers