Journal of neurotrauma
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Significant cardiovascular and autonomic dysfunction occurs after spinal cord injury (SCI). It is now recognized that cardiovascular disease is a leading cause of morbidity and mortality in SCI. Patients with SCI may also suffer severe orthostatic hypotension and autonomic dysreflexia. ⋯ Although no studies have examined the sympathetic arm of the baroreflex in those with SCI, despite this being arguably more important to blood pressure regulation than the cardiovagal baroreflex, nine articles have examined sympathetic responses to orthostatic challenges; these findings are reviewed. Future studies are needed to describe whether dysfunctional baroreflex sensitivity after SCI is due to arterial stiffening or a neural component. Further, measurement of forearm vascular conductance and/or muscle sympathetic nerve activity is required to directly evaluate the sensitivity of the sympathetic arm of the baroreflex in those with SCI.
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Journal of neurotrauma · Oct 2012
Persistence of disability 24 to 36 months after pediatric traumatic brain injury: a cohort study.
This study examined the outcome of 0- to 17-year-old children 36 months after traumatic brain injury (TBI), and ascertained if there was any improvement in function between 24 and 36 months. Controls were children treated in the emergency department for an arm injury. Functional outcome 36 months after injury was measured by the Pediatric Quality of Life Inventory (PedsQL), the self-care and communication subscales of the Adaptive Behavior Assessment Scale-2nd edition (ABAS-II), and the Child and Adolescent Scale of Participation (CASP). ⋯ Compared to the baseline assessment, children with moderate or severe TBI had significantly poorer functioning on the ABAS-II and poorer participation in activities (CASP). There was no significant improvement in any group on any outcomes between 24 and 36 months. Post-injury interventions that decrease the impact of these deficits on function and quality of life, as well as preventive interventions that reduce the likelihood of TBI, should be developed and tested.
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Journal of neurotrauma · Oct 2012
Cerebrovascular responses to orthostatic stress after spinal cord injury.
Orthostatic hypotension (OH) is a debilitating condition affecting individuals with spinal cord injury (SCI) that may be associated with cerebral hypoperfusion. We studied orthostatic cerebral control in individuals with SCI with different levels and severities of injury to spinal cardiovascular autonomic pathways. We measured beat-to-beat cardiovascular and cerebrovascular responses to passive orthostatic stress in 16 controls and 26 subjects with chronic SCI. ⋯ Individuals with autonomically complete SCI reported increased severity of symptoms relative to controls (p<0.05). Symptom severity was correlated with the efficacy of dynamic autoregulation. During orthostatic stress, SCI individuals have impaired cerebrovascular control that is related to the level and severity of autonomic injury.
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In order to quantify degenerative and regenerative changes and analyze the contribution of multiple factors to the outcome after neurite transection, we cultured adult mouse dorsal root ganglion neurons, and with a precise laser beam, we transected the nerve fibers they extended. Cell preparations were continuously visualized for 24 h with time-lapse microscopy. More distal cuts caused a more elongated field of degeneration, while thicker neurites degenerated faster than thinner ones. ⋯ Branching slowed the regenerative process, while simultaneous degeneration of uncut neurites increased it. Proximal lesions, small neuronal size, and extensive and rapid neurite degeneration were predictive of death of an injured neuron, which typically displayed necrotic rather than apoptotic form. In conclusion, this in vitro model proved useful in unmasking many new aspects and correlates of mechanically-induced neurite injury.
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Journal of neurotrauma · Oct 2012
A discrimination task used as a novel method of testing decision-making behavior following traumatic brain injury.
Traumatic brain injury (TBI) results in a multitude of deficits following injury. Some of the most pervasive in humans are the changes that affect frontally-mediated cognitive functioning, such as decision making. The assessment of decision-making behavior in rodents has been extensively tested in the field of the experimental analysis of behavior. ⋯ Upon reaching criterion, a reversal discrimination was evaluated in which the reinforcer was placed in unscented sand. Finally, a novel scent discrimination (basil versus coffee with basil reinforced), and a reversal (coffee) were evaluated. The results indicated that the Dig task is a simple experimental preparation that can be used to assess deficits in decision-making behavior following TBI.