Journal of neurotrauma
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Journal of neurotrauma · Jun 2011
Acute serum hormone levels: characterization and prognosis after severe traumatic brain injury.
Experimental traumatic brain injury (TBI) studies report the neuroprotective effects of female sex steroids on multiple mechanisms of injury, with the clinical assumption that women have hormonally mediated neuroprotection because of the endogenous presence of these hormones. Other literature indicates that testosterone may exacerbate injury. Further, stress hormone abnormalities that accompany critical illness may both amplify or blunt sex steroid levels. ⋯ Changes in the post-TBI adrenal response and peripheral aromatization influenced hormone TRAJ profiles and contributed to the abnormalities, including increased estradiol in men and increased testosterone in women. In addition to older age and greater injury severity, increased estradiol and testosterone levels over time were associated with increased mortality and worse global outcome for both men and women. These findings represent a paradigm shift when thinking about the role of sex steroids in neuroprotection clinically after TBI.
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Journal of neurotrauma · Jun 2011
Bimanual coordination and corpus callosum microstructure in young adults with traumatic brain injury: a diffusion tensor imaging study.
Bimanual actions are ubiquitous in daily life. Many coordinated movements of the upper extremities rely on precise timing, which requires efficient interhemispheric communication via the corpus callosum (CC). As the CC in particular is known to be vulnerable to traumatic brain injury (TBI), furthering our understanding of its structure-function association is highly valuable for TBI diagnostics and prognosis. ⋯ Finally, multiple regression analyses showed evidence of the high specificity of callosal subregions accounting for the variance associated with performance of the different bimanual coordination tasks. Whereas disruption in commissural pathways between occipital areas played a role in performance on the clinical tests of bimanual coordination, deficits in the switching task were related to disrupted interhemispheric communication in prefrontal, sensory, and parietal regions. This study provides evidence that structural alterations of several subregional callosal fibers in adults with TBI are associated with differential behavioral manifestations of bimanual motor functioning.
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Journal of neurotrauma · Jun 2011
Comparative StudyLong-term outcomes after uncomplicated mild traumatic brain injury: a comparison with trauma controls.
The question as to whether mild traumatic brain injury (mTBI) results in persisting sequelae over and above those experienced by individuals sustaining general trauma remains controversial. This prospective study aimed to document outcomes 1 week and 3 months post-injury following mTBI assessed in the emergency department (ED) of a major adult trauma center. One hundred and twenty-three patients presenting with uncomplicated mTBI and 100 matched trauma controls completed measures of post-concussive symptoms and cognitive performance (Immediate Post-Concussion Assessment and Cognitive Testing battery; ImPACT) and pre-injury health-related quality of life (SF-36) in the ED. ⋯ There were no significant group differences in psychiatric function. However, the group with mild TBI was more likely to report ongoing memory and concentration problems in daily activities. Further investigation of factors associated with these ongoing problems is warranted.
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Journal of neurotrauma · Jun 2011
Interaction between brain chemistry and physiology after traumatic brain injury: impact of autoregulation and microdialysis catheter location.
Bedside monitoring of cerebral metabolism in traumatic brain injury (TBI) with microdialysis is gaining wider clinical acceptance. The objective of this study was to examine the relationship between the fundamental physiological neuromonitoring modalities intracranial pressure (ICP), cerebral perfusion pressure (CPP), brain tissue oxygen (P(bt)O(2)), and cerebrovascular pressure reactivity index (PRx), and cerebral chemistry assessed with microdialysis, with particular focus on the lactate/pyruvate (LP) ratio as a marker of energy metabolism. Prospectively collected observational neuromonitoring data from 97 patients with TBI, requiring neurointensive care management and invasive cerebral monitoring, were analyzed. ⋯ These differences remained significant following adjustment for the influences of other important physiological parameters (ICP, CPP, P(bt)O(2), P(bt)CO(2), PRx, and brain temperature; mixed linear model), suggesting that they may reflect inherent tissue properties related to the initial injury. Despite inherent biochemical differences between less-injured brain and "perilesional" cerebral tissue, both tissue types exhibited relationships between established physiological variables and biochemistry. Decreases in perfusion and oxygenation were associated with deteriorating neurochemistry and these effects were more pronounced in perilesional tissue and when cerebrovascular reactivity was impaired.
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Journal of neurotrauma · Jun 2011
Activation of PI3 kinase/Akt signaling in chronic subdural hematoma outer membranes.
Chronic subdural hematoma (CSDH) is an angiogenic disease that is recognized as a cause of treatable dementia with unknown pathogenesis. Vascular endothelial growth factor (VEGF), a potent growth factor regulating angiogenesis through the phosphatidylinositol 3-kinase (PI3-kinase)/Akt pathway, has been implicated in its etiology. The status of this signaling pathway in CSDH outer membranes was examined in the present study, using outer membranes obtained during trepanation surgery. ⋯ PI3-kinase, Akt, eNOS, and VE-cadherin were detected in all cases. The magnitude of the expression of p-Akt varied among cases; however, the localization was revealed to be present in endothelial cells of vessels in CSDH outer membranes, together with VEGF and VE-cadherin detected in endothelial cells of vessels. These findings suggest that the PI3-kinase/Akt signaling is activated in CSDH outer membranes, and indicate the possibility that the PI3 kinase/Akt pathway might be activated by VEGF and play a critical role in the angiogenesis of CSDH.