Journal of neurotrauma
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Journal of neurotrauma · Jul 2011
Cortical excitability changes in patients with sleep-wake disturbances after traumatic brain injury.
Although chronic sleepiness is common after head trauma, the cause remains unclear. Transcranial magnetic stimulation (TMS) represents a useful complementary approach in the study of sleep pathophysiology. We aimed to determine in this study whether post-traumatic sleep-wake disturbances (SWD) are associated with changes in excitability of the cerebral cortex. ⋯ Similarly to that reported in patients with narcolepsy, the cortical hypoexcitability may reflect the deficiency of the excitatory hypocretin/orexin-neurotransmitter system. These observations may provide new insights into the causes of chronic sleepiness in patients with TBI. A better understanding of the pathophysiology of post-traumatic SWD may also lead to better therapeutic strategies in these patients.
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Amiloride is a drug approved by the United States Food and Drug Administration, which has shown neuroprotective effects in different neuropathological conditions, including brain injury or brain ischemia, but has not been tested in spinal cord injury (SCI). We tested amiloride's therapeutic potential in a clinically relevant rat model of contusion SCI inflicted at the thoracic segment T10. ⋯ Our data indicate that higher levels of MOG correlate with improved locomotor recovery after SCI, and that this may explain the beneficial effects of amiloride after SCI. Given that amiloride treatment after SCI caused a significant preservation of myelin levels, and improved locomotor recovery, it should be considered as a possible therapeutic intervention after SCI.
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Journal of neurotrauma · Jul 2011
Short-term moderate hypocapnia augments detection of optimal cerebral perfusion pressure.
An autoregulation-oriented strategy has been proposed to guide neurocritical therapy toward the optimal cerebral perfusion pressure (CPPOPT). The influence of ventilation changes is, however, unclear. We sought to find out whether short-term moderate hypocapnia (HC) shifts the CPPOPT or affects its detection. ⋯ Moderate HC did not shift this CPPOPT but enabled its detection in another 17 patients (CPPOPT left: 83.94±14.82; right: 85.28±14.73 mm Hg). The detection of CPPOPT was achieved via significantly improved Mx-autoregulatory index and an increase of CPP mean. It appeared that short-term moderate HC augmented the detection of an optimum CPP, and may therefore usefully support CPP-guided therapy in patients with TBI.
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Journal of neurotrauma · Jul 2011
Traumatic axonal injury in the optic nerve: evidence for axonal swelling, disconnection, dieback, and reorganization.
Traumatic axonal injury (TAI) is a major feature of traumatic brain injury (TBI) and is associated with much of its morbidity. To date, significant insight has been gained into the initiating pathogenesis of TAI. However, the nature of TAI within the injured brain precludes the consistent evaluation of its specific anterograde and retrograde sequelae. ⋯ Concomitant with this evolving axonal pathology, focal YFP fluorescence quenching occurred and mapped precisely to immunoreactive loci positive for Texas-Red-conjugated-IgG, indicating that blood-brain barrier disruption and its attendant edema contributed to this phenomenon. This was confirmed through the use of antibodies targeting endogenous YFP, which demonstrated the retention of intact immunoreactive axons despite YFP fluorescence quenching. Collectively, the results of this study within the injured optic nerve provide unprecedented insight into the evolving pathobiology associated with TAI.
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Journal of neurotrauma · Jul 2011
Comparative StudyObjective measures of motor dysfunction after compression spinal cord injury in adult rats: correlations with locomotor rating scores.
Precise assessment of motor deficits after traumatic spinal cord injury (SCI) in rodents is crucial for understanding the mechanisms of functional recovery and testing therapeutic approaches. Here we analyzed the applicability to a rat SCI model of an objective approach, the single-frame motion analysis, created and used for functional analysis in mice. Adult female Wistar rats were subjected to graded compression of the spinal cord. ⋯ FSA co-varied with RHI only in the severely impaired rats, while RHI and CLS were barely correlated. Our findings suggest that the numerical parameters estimate, as intended by design, predominantly different aspects of locomotion. The use of these objective measures combined with BBB rating provides a time- and cost-efficient opportunity for versatile and reliable functional evaluations in both severely and moderately impaired rats, combining clinical assessment with precise numerical measures.