1,720,987 research outputs found
Intestinal ischemia/reperfusion promotes brain damage via microglia activation: can we do something now?
No full textNeuroprotective properties of xenon and helium in an in vitro model of traumatic brain injury: one small step or one big jump?
No full textThe cholinergic system in Down's syndrome.
No full textThe cholinergic system is one of the most important modulatory neurotransmitter systems in the brain. Alterations of the transmission communicators are accompanied by reduction of the cortical activity, which is associated with a learning and memory deficit. Down's syndrome is a pathological condition characterized by a high number of abnormalities that involve the brain.The cholinergic system is involved in alterations of the neurological system such as severe learning difficulties.To explain these alterations, important results are obtained from studies about murine trisomy 16 (animal model of Down's syndrome).The results obtained provide useful elements in the improvement of knowledge about the neurological and neurotransmissional alterations that are responsible for the neurobiological characteristics of Down's syndrome.These data potentially justify, in these patients, the therapeutic use of drugs that are principally administered to improve the severe learning difficulties of people with Alzheimer's disease, and suggest a trend which generates a hypothesis worthy of further exploration. © 2006 Sage Publications
Anaesthetic-related neuroprotection: intravenous or inhalational agents?
No full textIn designing the anaesthetic plan for patients undergoing surgery, the choice of anaesthetic agent may often appear irrelevant and the best results obtained by the use of a technique or a drug with which the anaesthesia care provider is familiar. Nevertheless, in those surgical procedures (cardiopulmonary bypass, carotid surgery and cerebral aneurysm surgery) and clinical situations (subarachnoid haemorrhage, stroke, brain trauma and post-cardiac arrest resuscitation) where protecting the CNS is a priority, the choice of anaesthetic drug assumes a fundamental role. Treating patients with a neuroprotective agent may be a consideration in improving overall neurological outcome. Therefore, a clear understanding of the relative degree of protection provided by various agents becomes essential in deciding on the most appropriate anaesthetic treatment geared to these objectives. This article surveys the current literature on the effects of the most commonly used anaesthetic drugs (volatile and gaseous inhalation, and intravenous agents) with regard to their role in neuroprotection. A systematic search was performed in the MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINHAL®) and Cochrane Library databases using the following keywords: 'brain' (with the limits 'newborn' or 'infant' or 'child' or 'neonate' or 'neonatal' or 'animals') AND 'neurodegeneration' or 'apoptosis' or 'toxicity' or 'neuroprotection' in combination with individual drug names ('halothane', 'isoflurane', 'desflurane', 'sevoflurane', 'nitrous oxide', 'xenon', 'barbiturates', 'thiopental', 'propofol', 'ketamine'). Over 600 abstracts for articles published from January 1980 to April 2010, including studies in animals, humans and in vitro, were examined, but just over 100 of them were considered and reviewed for quality. Taken as a whole, the available data appear to indicate that anaesthetic drugs such as barbiturates, propofol, xenon and most volatile anaesthetics (halothane, isoflurane, desflurane, sevoflurane) show neuroprotective effects that protect cerebral tissue from adverse events--such as apoptosis, degeneration, inflammation and energy failure--caused by chronic neurodegenerative diseases, ischaemia, stroke or nervous system trauma. Nevertheless, in several studies, the administration of gaseous, volatile and intravenous anaesthetics (especially isoflurane and ketamine) was also associated with dose-dependent and exposure time-dependent neurodegenerative effects in the developing animal brain. At present, available experimental data do not support the selection of any one anaesthetic agent over the others. Furthermore, the relative benefit of one anaesthetic versus another, with regard to neuroprotective potential, is unlikely to form a rational basis for choice. Each drug has some undesirable adverse effects that, together with the patient's medical and surgical history, appear to be decisive in choosing the most suitable anaesthetic agent for a specific situation. Moreover, it is important to highlight that many of the studies in the literature have been conducted in animals or in vitro; hence, results and conclusions of most of them may not be directly applied to the clinical setting. For these reasons, and given the serious implications for public health, we believe that further investigation--geared mainly to clarifying the complex interactions between anaesthetic drug actions and specific mechanisms involved in brain injury, within a setting as close as possible to the clinical situation--is imperative
Neuroprotection by erythropoietin administration after experimental traumatic brain injury.
Full text linkA large body of evidence indicates that the hormone erythropoietin (EPO) exerts beneficial effects in the central nervous system (CNS). To date, EPO's effect has been assessed in several experimental models of brain and spinal cord injury. This study was conducted to validate whether treatment with recombinant human EPO (rHuEPO) would limit the extent of injury following experimental TBI. Experimental TBI was induced in rats by a cryogenic injury model. rHuEPO or placebo was injected intraperitoneally immediately after the injury and then every 8 h until 2 or 14 days. Forty-eight hours after injury brain water content, an indicator of brain edema, was measured with the wet-dry method and blood-brain barrier (BBB) breakdown was evaluated by assay of Evans blue extravasation. Furthermore, extent of cerebral damage was assessed. Administration of rHuEPO markedly improved recovery from motor dysfunction compared with placebo group (P < 0.05). Brain edema was significantly reduced in the cortex of the EPO-treated group relative to that in the placebo-treated group (80.6 ± 0.3% versus 91.8% ± 0.8% respectively, P < 0.05). BBB breakdown was significantly lower in EPO-treated group than in the placebo-treated group (66.2 ± 18.7 μg/g versus 181.3 ± 21 μg/g, respectively, P < 0.05). EPO treatment reduced injury volume significantly compared with placebo group (17.4 ± 5.4 mm3 versus 37.1 ± 5.3 mm3, P < 0.05). EPO, administered in its recombinant form, affords significant neuroprotection in experimental TBI model and may hold promise for future clinical applications. © 2007 Elsevier B.V. All rights reserved
Postoperative cognitive dysfunction: toward the Alzheimer disease: Pathomechanism Hypothesis
No full textAlzheimer’s disease (AD), a chronic and progressive deterioration of memory and other cognitive domains, is the
most common form of dementia. Because of related health and social impact, there is growing interest in assessing potential
relationship between anesthesia and the onset and progression of chronic neurodegenerative disorders, including AD. Currently,
preclinical and clinical research is addressed to identify underlying pathomechanisms, patient risk factors, and the use of the
least provocative drugs and techniques, to minimize the incidence of chronic neurodegenerative disorders. Preclinical studies are
providing an increasing body of evidences on some of the mechanisms that link anesthetics to neuronal programmed cell death
(apoptosis) and accumulation of misfolded proteins in the aging brain. Therefore, risk factors and pathomechanisms of chronic
neurodegenerative disorders, including AD, and persistent postoperative-postanesthesia cognitive dysfunction may overla
Neuroprotective potential of erythropoietin and darbepoetin alfa in an experimental model of sciatic nerve injury. Laboratory investigation
No full textObject. The objectives of this study were to examine whether the systemic administration of recombinant human erythropoietin (rHuEPO) and its long-lasting derivative darbepoetin alfa expedited functional recovery in a rat model of sciatic nerve injury, and to compare the effects of these agents in the model. Methods. Thirty male Sprague-Dawley rats received a crush injury to the left sciatic nerve and subsequently underwent either placebo treatment, daily injections of rHuEPO, or weekly injections of darbepoetin alfa. Results. Both rHuEPO and darbepoetin alfa were effective in reducing neurological impairment and improving compound muscle action potentials following nerve injury. Darbepoetin alfa, however, shortened the duration of peripheral nerve recovery and facilitated recovery from the neurological and electrophysiological impairment following crush injury significantly better than rHuEPO. Examination of the footprint length factor data revealed that darbepoetin alfa-treated animals recovered preinjury function by postoperative Day 10, 4 days earlier than animals treated with rHuEPO and 11 days earlier than animals treated with placebo. Conclusions. These results suggest that recovery of neurological function in a model of peripheral nerve injury is more rapid with weekly administration of darbepoetin alfa than with daily rHuEPO treatment. Agents that facilitate nerve regeneration have the potential to limit the extent of motor endplate loss and muscle atrophy. The administration of EPO in its long-lasting recombinant forms affords significant neuroprotection in peripheral nerve injury models and may hold promise for future clinical applications
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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