985 resultados para Receptores NMDA


Relevância:

10.00% 10.00%

Publicador:

Resumo:

El problema de controlar les emissions de televisió digital a tota Europa pel desenvolupament de receptors robustos i fiables és cada vegada més significant, per això, sorgeix la necessitat d’automatitzar el procés d’anàlisi i control d’aquests senyals. Aquest projecte presenta el desenvolupament software d’una aplicació que vol solucionar una part d’aquest problema. L’aplicació s’encarrega d’analitzar, gestionar i capturar senyals de televisió digital. Aquest document fa una introducció a la matèria central que és la televisió digital i la informació que porten els senyals de televisió, concretament, la que es refereix a l’estàndard "Digital Video Broadcasting". A continuació d’aquesta part, l’escrit es concentra en l’explicació i descripció de les funcionalitats que necessita cobrir l'aplicació, així com introduir i explicar cada etapa d’un procés de desenvolupament software. Finalment, es resumeixen els avantatges de la creació d’aquest programa per l’automatització de l’anàlisi de senyal digital partint d’una optimització de recursos.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Converging evidence favors an abnormal susceptibility to oxidative stress in schizophrenia. Decreased levels of glutathione (GSH), the major cellular antioxidant and redox regulator, was observed in cerebrospinal-fluid and prefrontal cortex of patients. Importantly, abnormal GSH synthesis of genetic origin was observed: Two case-control studies showed an association with a GAG trinucleotide repeat (TNR) polymorphism in the GSH key synthesizing enzyme glutamate-cysteine-ligase (GCL) catalytic subunit (GCLC) gene. The most common TNR genotype 7/7 was more frequent in controls, whereas the rarest TNR genotype 8/8 was three times more frequent in patients. The disease associated genotypes (35% of patients) correlated with decreased GCLC protein, GCL activity and GSH content. Similar GSH system anomalies were observed in early psychosis patients. Such redox dysregulation combined with environmental stressors at specific developmental stages could underlie structural and functional connectivity anomalies. In pharmacological and knock-out (KO) models, GSH deficit induces anomalies analogous to those reported in patients. (a) morphology: spine density and GABA-parvalbumine immunoreactivity (PV-I) were decreased in anterior cingulate cortex. KO mice showed delayed cortical PV-I at PD10. This effect is exacerbated in mice with increased DA from PD5-10. KO mice exhibit cortical impairment in myelin and perineuronal net known to modulate PV connectivity. (b) physiology: In cultured neurons, NMDA response are depressed by D2 activation. In hippocampus, NMDA-dependent synaptic plasticity is impaired and kainate induced g-oscillations are reduced in parallel to PV-I. (c) cognition: low GSH models show increased sensitivity to stress, hyperactivity, abnormal object recognition, olfactory integration and social behavior. In a clinical study, GSH precursor N-acetyl cysteine (NAC) as add on therapy, improves the negative symptoms and decreases the side effects of antipsychotics. In an auditory oddball paradigm, NAC improves the mismatched negativity, an evoked potential related to pre-attention and to NMDA receptors function. In summary, clinical and experimental evidence converge to demonstrate that a genetically induced dysregulation of GSH synthesis combined with environmental insults in early development represent a major risk factor contributing to the development of schizophrenia Conclusion Based on these data, we proposed a model for PSIP1 promoter activity involving a complex interplay between yet undefined regulatory elements to modulate gene expression.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

RESUME : Dans ce travail effectué chez le rat adulte, l'excitotoxicité rétinienne est élicitée par injection intravitréenne de NMDA. Les lésions en résultant sont localisées dans la rétine interne. Elles prennent la forme de pycnoses dans la couche des cellules ganglionnaires (corps cellulaires des cellules ganglionnaires et amacrines déplacées) et dans la partie interne de la couche nucléaire interne (cellules amacrines). Cette localisation est liée à la présence de récepteurs au glutamate de type NMDA sur ces cellules. L'activation de ces récepteurs entraîne un influx calcique et l'activation de diverses enzymes (phospholipase A, calpaïnes, calmoduline, synthase d'oxyde nitrique). La signalisation se poursuit en aval en partie par les voies des Mitogen Activated Protein Kinase (MAPK) : ERK, p38, ]NK. Dans les expériences présentées, toutes trois sont activées après l'injection de NMDA. Dans les cascades de signalisation de JNK, trois kinases s'ancrent sur une protéine scaffold. Les MAPKKK phosphorylent MKK4 et MKK7, qui phosphorylent JNK. JNK a de nombreuses cibles nucléaires (dont le facteur de transcription c-Jun) et cytoplasmiques. La voie de JNK est bloquée par l'inhibiteur peptidique D-JNKI-1 en empêchant l'interaction de la kinase avec son substrat. L'inhibiteur est formé de 20 acides aminés du domaine de liaison JBD et de 10 acides aminés de la partie TAT du virus HIV. L'injection intravitréenne de D-JNKI-1 permet une diminution des taux de JNK et c-Jun phosphorylés dans les lysats de rétine. L'effet prépondérant est la restriction importante des altérations histologiques des couches internes de la rétine. L'évaluation par électrorétinogramme met en sus en évidence une sauvegarde de la fonction cellulaire. Ce travail a ainsi permis d'établir la protection morphologique et fonctionnelle des cellules de la rétine interne par inhibition spécifique de la voie de JNK lors d'excitotoxicité. SUMMARY Excitotoxicity in the retina associates with several pathologies like retinal ischemia, traumatic optic neuropathy and glaucoma. In this study, excitotoxicity is elicited by intravitreal NMDA injection in adult rats. Lesions localise in the inner retina. They present as pyknotic cells in the ganglion cell layer (ganglion cells and displaced amacrines) and the inner nuclear layer (amacrine cells). These cells express NMDA glutamate receptors. The receptor activation leads to a calcium flow into the cell and hence enzyme activation (phospholipase, calpains, calmodulin, nitric oxide synthase). The subsequent signaling pathways can involve the Mitogen Activated Protein Kinases (MAPK): ERK, p38 end JNK. These were all activated in our experiments. The signaling cascade organises around several scaffold proteins. The various MAPKKK phosphorylate MKK4 and MKK7, which phosphorylate JNK. JNK targets are of nuclear (c-Jun transcription factor) or cytoplasmic localisation. The peptidic inhibitor D-JNKI-1, 20 amino acids from the JNK binding domain JBD coupled to 10 amino acids of the TAT transporter, disrupts the binding of JNK with its substrate. Intravitreal injection of the inhibitor lowers phosphorylated forms of JNK and c-Jun in retinal extracts. It protects strongly against histological lesions in the inner retina and allows functional rescue.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

High doses of dextromethorphan (20-42 mg/kg/day) were given to four critically ill children with seizures and frequent epileptiform abnormalities in the EEG that were refractory to antiepileptic drugs. Their acute diseases (hypoxia, head trauma and hypoxia, neurodegenerative disease, hypoglycaemia) were thought to be due in part to N-methyl-D-aspartate (NMDA) receptor mediated processes. Treatment with dextromethorphan, an NMDA receptor antagonist, was started between 48 hours and 14 days after the critical incident. In three patients the EEG improved considerably within 48 hours and seizures ceased within 72 hours. In the patient with neurodegenerative disease the effect on the EEG was impressive, but the seizures were not controlled. Despite the improvement of the EEG the clinical outcome was poor in all children: three died in the critical period or due to the progressing disease; the patient with hypoglycaemia survived with severe neurological sequelae. Plasma concentrations of dextromethorphan varied between 74-1730 ng/ml and its metabolite dextrorphan varied between 349-3790 ng/ml. In one patient corresponding concentrations in CSF were lower than those in plasma. The suppression of epileptic discharges by the doses of dextromethorphan given suggests that such doses are sufficient to block NMDA receptors.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Presenilin 1 (PS1) mutations are responsible for a majority of early onset familial Alzheimer's disease (FAD) cases, in part by increasing the production of Abeta peptides. However, emerging evidence suggests other possible effects of PS1 on synaptic dysfunction where PS1 might contribute to the pathology independent of Abeta. We chose to study the L286V mutation, an aggressive FAD mutation which has never been analyzed at the electrophysiological and morphological levels. In addition, we analyzed for the first time the long term effects of wild-type human PS1 overexpression. We investigated the consequences of the overexpression of either wild-type human PS1 (hPS1) or the L286V mutated PS1 variant (mutPS1) on synaptic functions by analyzing synaptic plasticity and associated spine density changes from 3 to 15 months of age. We found that mutPS1 induces a transient increase observed only in 4- to 5-month-old mutPS1 animals in NMDA receptor (NMDA-R)-mediated responses and LTP compared with hPS1 mice and nontransgenic littermates. The increase in synaptic functions is concomitant with an increase in spine density. With increasing age, however, we found that the overexpression of human wild-type PS1 progressively decreased NMDA-R-mediated synaptic transmission and LTP, without neurodegeneration. These results identify for the first time a transient increase in synaptic function associated with L286V mutated PS1 variant in an age-dependent manner. In addition, they support the view that the PS1 overexpression promotes synaptic dysfunction in an Abeta-independent manner and underline the crucial role of PS1 during both normal and pathological aging.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

El nostre objectiu és avaluar l’impacte de la utilització de fetges de donants anti-HBc positius en pacients trasplantats per hepatitis B, els quals van ser revisats de manera retrospectiva. La probabilitat acumulada d’hepatitis B post-trasplantament al 1er, 5é i 10é any va ésser del 3,7%, 8,3% i 8,3% en els receptors d’un empelt anti-HBc+ en comparació amb el 2,7%, 9,8% i 9,8% en els que varen rebre un empelt anti-HBc- (p=0,99). La probabilitat de supervivència al 1er, 5é i 10é any dels receptors d’un òrgan anti-HBc+ va ésser del 87%, 82% i 58% front al 87%, 82% i 74% en els que varen rebre un anti-HBc- (p=0,73). La utilització de donants anti-HBc positius no afecta ni a la supervivència ni al desenvolupament de hepatitis B en pacients trasplantats per VHB.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Investigación producida a partir de una estancia en la University of Sidney, Australia, entre octubre del 2008 y enero del 2009. Se ha desarrollado el proyecto titulado "Papel de la interleucina 6 (IL6) en la regulación de la expresión de Osteopontina (OPN) y de CD44 tras axotomía del nervio facial". Tras efectuar una transección del nervio facial, se indujo una reactividad glial en el núcleo facial (NF) localizado en el tronco cerebral, utilizando ratones transgénicos que sobrexpresan IL6 bajo promotor GFAP (tg GFAP-IL6), es decir selectivamente en astrocitos. Se han utilizado técnicas histoquímicas e inmunohistoquímicas, así como también se ha completado el estudio utilizando análisis de RPA, western blotting y citometría de flujo para la identificación de poblaciones celulares. Los resultados obtenidos indican que la OPN se expresa constitutivamente en las neuronas del NF. Tras axotomía del nervio facial, la expresión de OPN y CD44 incrementa en los ratones WT, mientras que en los tg GFAP-IL6 disminuye significativamente, sugiriendo que la IL6 podría estar involucrada en la modulación de la expresión de ambas moléculas. Sin embargo, no se ha visto diferencias en otros receptores de OPN como la integrina Alpha-5. La ctometría de flujo corroboró algunos de los resultados histológicos sobre la reactividad microglial y permitió concluir que la proporción de microglía activada (CD11b+/CD45+mid) y macrófagos (CD11b+/CD45+high) que expresan CD44 incrementa en in los tg GFAP-IL6 versus WT donde la mayor parte de microglia activada mostraba un perfil CD11b+/CD45+low.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Antecedentes: La infección por CMV es la más frecuente que sufren los receptores de trasplante de órgano sólido (TOS) en los primeros meses del trasplante. Son abundantes las estrategias de prevención y tratamiento de la enfermedad por CMV que se han desarrollado. Métodos: El objetivo fue evaluar la incidencia y severidad de la enfermedad por CMV en 387 receptores de trasplante renal que recibieron tratamiento profiláctico (grupo de alto riesgo, n = 251) o realizaron seguimiento de PCR de CMV por ser grupo de bajo riesgo (n = 136) y recibieron tratamiento anticipado (n = 17) con valganciclovir oral (900 mg/día) cuando presentaron & 1000 copias/ml. Resultados: Presentaron enfermedad por CMV, 2 (11,76%) pacientes del grupo de riesgo estándar, descrita como enfermedad leve y 20 (7,96%) pacientes del grupo de alto riesgo, descrita como enfermedad leve en 15 casos y como enfermedad grave en 5 casos. Aquellos pacientes que desarrollaron la enfermedad, respondieron al tratamiento con ganciclovir endovenoso durante 14 días seguido de valganciclovir oral hasta completar tres meses. Conclusión: El tratamiento profiláctico con valganciclovir oral para la prevención de enfermedad o infección por CMV solamente es necesario en los receptores de TOS de alto riesgo.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The group I metabotropic glutamate receptor 5 (mGluR5) has been implicated in the development of cortical sensory maps. However, its precise roles in the synaptic function and plasticity of thalamocortical (TC) connections remain unknown. Here we first show that in mGluR5 knockout (KO) mice bred onto a C57BL6 background cytoarchitectonic differentiation into barrels is missing, but the representations for large whiskers are identifiable as clusters of TC afferents. The altered dendritic morphology of cortical layer IV spiny stellate neurons in mGluR5 KO mice implicates a role for mGluR5 in the dendritic morphogenesis of excitatory neurons. Next, in vivo single-unit recordings of whisker-evoked activity in mGluR5 KO adults demonstrated a preserved topographical organization of the whisker representation, but a significantly diminished temporal discrimination of center to surround whiskers in the responses of individual neurons. To evaluate synaptic function at TC synapses in mGluR5 KO mice, whole-cell voltage-clamp recording was conducted in acute TC brain slices prepared from postnatal day 4-11 mice. At mGluR5 KO TC synapses, N-methyl-D-aspartate (NMDA) currents decayed faster and synaptic strength was more easily reduced, but more difficult to strengthen by Hebbian-type pairing protocols, despite a normal developmental increase in alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)-mediated currents and presynaptic function. We have therefore demonstrated that mGluR5 is required for synaptic function/plasticity at TC synapses as barrels are forming, and we propose that these functional alterations at the TC synapse are the basis of the abnormal anatomical and functional development of the somatosensory cortex in the mGluR5 KO mouse.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Aim We report four cases of acquired severe encephalopathy with massive hyperkinesia, marked neurological and cognitive regression, sleep disturbance, prolonged mutism, and a remarkably delayed recovery (time to full recovery between 5 and 18mo) with an overall good outcome, and its association with anti-N-methyl-d-aspartate (anti-NMDA) receptor antibodies. Method We reviewed the four cases retrospectively and we also reviewed the literature. Results Anti-NMDA receptor antibodies (without ovarian teratoma detected so far) were found in the two children tested in this study. Interpretation The clinical features are similar to those first reported in 1992 by Sebire et al.,(1) and rarely recognized since. Sleep disturbance was not emphasized as part of the disorder, but appears to be an important feature, whereas coma is less certain and difficult to evaluate in this setting. The combination of symptoms, evolution (mainly seizures at onset), severity, paucity of abnormal laboratory findings, very slow recovery, and difficult management justify its recognition as a specific entity. The neuropathological substrate may be anatomically close to that involved in encephalitis lethargica, in which the same target functions (sleep and movement) are affected but in reverse, with hypersomnolence and bradykinesia. This syndrome closely resembles anti-NMDA receptor encephalitis, which has been reported in adults and is often paraneoplastic.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

L'objectiu d'aquest projecte és l'anàlisi, disseny i la seva corresponent implementació d'una solució basada en programari per a poder gestionar un conjunt de fabriques de televisors i monitors en quan a la gestió de l'estoc d'escandall, la gestió de les OF's i la gestió dels FR.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

La resolució de la problemàtica exposada al llarg d'aquest treball s'aborda en dues fases. Una primera constitueix un estudi teòric dels diversos conceptes implicats: SIG, cartografia, geodèsia i GPS, amb especial atenció al tipus de receptors GPS disponibles al mercat. La segona part és eminentment pràctica i està formada per l'exposició de la solució adoptada per a respondre a les necessitats de l'empresa

Relevância:

10.00% 10.00%

Publicador:

Resumo:

There is increasing recognition of an autoimmune origin of pharmacoresistant epileptic disorders. Besides the paraneoplastic limbic encephalopathies (LE), reports of syndromes of non-paraneoplastic LE are increasingly reported in the last 5-10 years. Three antibodies are now relatively well described: Voltagegated potassium channels (VGKC), Glutamic acid decarboxylase (GAD) and N-methyl-D-apartate receptor-(NMDA) antibodies. We review clinical syndromes, associated imaging and laboratory findings. While most reports arise from adult populations, children and adolescents are also concerned as evidenced by increasing observations. Early recognition is mandatory, since early immunomodulatory treatment appears to be related to significant better outcome.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Background: Androgens are key regulators of prostate gland maintenance and prostate cancer growth, and androgen deprivation therapy has been the mainstay of treatment for advanced prostate cancer for many years. A long-standing hypothesis has been that inherited variation in the androgen receptor (AR) gene plays a role in prostate cancer initiation. However, studies to date have been inconclusive and often suffered from small sample sizes. Objective and Methods: We investigated the association of AR sequence variants with circulating sex hormone levels and prostate cancer risk in 6058 prostate cancer cases and 6725 controls of Caucasian origin within the Breast and Prostate Cancer Cohort Consortium. We genotyped a highly polymorphic CAG microsatellite in exon 1 and six haplotype tagging single nucleotide polymorphisms and tested each genetic variant for association with prostate cancer risk and with sex steroid levels. Results: We observed no association between AR genetic variants and prostate cancer risk. However, there was a strong association between longer CAG repeats and higher levels of testosterone (P = 4.73 × 10−5) and estradiol (P = 0.0002), although the amount of variance explained was small (0.4 and 0.7%, respectively). Conclusions: This study is the largest to date investigating AR sequence variants, sex steroid levels, and prostate cancer risk. Although we observed no association between AR sequence variants and prostate cancer risk, our results support earlier findings of a relation between the number of CAG repeats and circulating levels of testosterone and estradiol.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The TNF-related apoptosis inducing ligand (TRAIL)/TRAIL receptor system participates in crucial steps in immune cell activation or differentiation. It is able to inhibit proliferation and activation of T cells and to induce apoptosis of neurons and oligodendrocytes, and seems to be implicated in autoimmune diseases. Thus, TRAIL and TRAIL receptor genes are potential candidates for involvement in susceptibility to multiple sclerosis (MS). To test whether single-nucleotide polymorphisms (SNPs) in the human genes encoding TRAIL, TRAILR-1, TRAILR-2, TRAILR-3 and TRAILR-4 are associated with MS susceptibility, we performed a candidate gene case-control study in the Spanish population. 59 SNPs in the TRAIL and TRAIL receptor genes were analysed in 628 MS patients and 660 controls, and validated in an additional cohort of 295 MS patients and 233 controls. Despite none of the SNPs withstood the highly conservative Bonferroni correction, three SNPs showing uncorrected p values<0.05 were successfully replicated: rs4894559 in TRAIL gene, p = 9.8×10(-4), OR = 1.34; rs4872077, in TRAILR-1 gene, p = 0.005, OR = 1.72; and rs1001793 in TRAILR-2 gene, p = 0.012, OR = 0.84. The combination of the alleles G/T/A in these SNPs appears to be associated with a reduced risk of developing MS (p = 2.12×10(-5), OR = 0.59). These results suggest that genes of the TRAIL/TRAIL receptor system exerts a genetic influence on MS.