871 resultados para parabiotic cultures


Relevância:

20.00% 20.00%

Publicador:

Resumo:

N-Methyl-D-aspartate (NMDA) receptor-mediated neurotoxicity may depend, in part, on the generation of nitric oxide (NO.) and superoxide anion (O2.-), which react to form peroxynitrite (OONO-). This form of neurotoxicity is thought to contribute to a final common pathway of injury in a wide variety of acute and chronic neurologic disorders, including focal ischemia, trauma, epilepsy, Huntington disease, Alzheimer disease, amyotrophic lateral scelerosis, AIDS dementia, and other neurodegenerative diseases. Here, we report that exposure of cortical neurons to relatively short durations or low concentrations of NMDA, S-nitrosocysteine, or 3-morpholinosydnonimine, which generate low levels of peroxynitrite, induces a delayed form of neurotoxicity predominated by apoptotic features. Pretreatment with superoxide dismutase and catalase to scavenge O2.- partially prevents the apoptotic process triggered by S-nitrosocysteine or 3-morpholinosydnonimine. In contrast, intense exposure to high concentrations of NMDA or peroxynitrite induces necrotic cell damage characterized by acute swelling and lysis, which cannot be ameliorated by superoxide dismutase and catalase. Thus, depending on the intensity of the initial insult, NMDA or nitric oxide/superoxide can result in either apoptotic or necrotic neuronal cell damage.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Voltage- and ligand-activated channels in embryonic neurons containing luteinizing hormone-releasing hormone (LHRH) were studied by patch-pipette, whole-cell current and voltage clamp techniques. LHRH neurons were maintained in explant cultures derived from olfactory pit regions of embryonic mice. Cells were marked intracellularly with Lucifer yellow following recording. Sixty-two cells were unequivocally identified as LHRH neurons by Lucifer yellow and LHRH immunocytochemistry. The cultured LHRH neurons had resting potentials around -50 mV, exhibited spontaneous discharges generated by intrinsic and/or synaptic activities and contained a time-dependent inward rectifier (Iir). Voltage clamp analysis of ionic currents in the LHRH neuron soma revealed a tetrodotoxin-sensitive Na+ current (INa) and two major types of K+ currents, a transient current (IA), a delayed rectifier current (IK) and low- and high-voltage-activated Ca2+ currents. Spontaneous depolarizing synaptic potentials and depolarizations induced by direct application of gamma-aminobutyrate were both inhibited by picrotoxin or bicuculline, demonstrating the presence of functional gamma-aminobutyrate type A synapses on these neurons. Responses to glutamate were found in LHRH neurons in older cultures. Thus, embryonic LHRH neurons not yet positioned in their postnatal environment in the forebrain contained a highly differentiated repertoire of voltage- and ligand-gated channels.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

"Some of the finest interpretations ot nature ever to be expressed by an were painted by the Minoan fresco artists of Crete. Discovered only since the turn of the 20th century, the Kinoan Bronze Age civilization was amazingly progressive and notably modern. Apparently, the Minoans gained their high standard of living mainly through economic prosperity and secarity provided by a great navy. Arts, architecture and craft relice uncovered have been numerous, well-preserved and invaluable sources of historical knowledge"

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper discusses how Bosnia and Herzegovina (BiH) can boost its stalled economy by generating jobs and increasing film-tourism, while simultaneously helping unite its culturally divided nation, by building a film/TV production industry looking to Northern Ireland's successful model following its similarly violent history. Evidence is presented substantiating that BiH has the infrastructure and workforce from which to grow a film/TV production industry, but it must be built through large-scale foreign productions like Northern Ireland did with Game of Thrones. Examining studies conducted by industry experts, strategies are offered for building a competitive and sustainable film/TV production industry in BiH. Results reveal more research is needed evidencing film/TV production can unify people from different ethno-religious/political groups in post-conflict societies.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Seventy-five years ago, Walter Benjamin showed us that the line between "production" and "reproduction" had begun to blur. Reproduction was no longer optional, consequential and degrading (the shredding of the original’s aura), but was instead being transformed into a principle of production itself: something was produced bearing in mind how it was to be reproduced. No longer did the original exist (in photography, film, music recordings), but instead diffusion, exhibition. The work existed precisely at the time and place of its enjoyment. Today, the cultural pirates of the new digital era take this principle to the extreme, with a certain characteristic also foreseen by Benjamin: a yearning to participate, to post-produce something captured in order to later return it to the Internet, modified in some way and made available to others. This postproduction is what is now often mixed up with reception, just as production and reproduction used to be in Benjamin’s day. Postproduction on the receiver’s side, which somehow augments and extends the received work, in other words creates an etymologically rigorous author-ization (auctor as the root of both author and augmentation). The cultural pirate only deserves redemption thanks to this creative augmentation.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

Relevância:

20.00% 20.00%

Publicador:

Resumo:

"Literature references": p. 337-340.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Mode of access: Internet.