Journal of neurotrauma
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Polyuria contributes to bladder overdistention, which confounds both lower and upper urinary tract management in individuals having a spinal cord injury (SCI). Bladder overdistention post-SCI is one of the most common triggers for autonomic dysreflexia, a potentially life-threatening condition. Post-SCI polyuria is thought to result from loss of vascular tone in the lower extremities, leading to edema and subsequent excess fluid, resulting in polyuria. ⋯ Step training (30 min/day, 6 days/week) did not alleviate polyuria in the moderate SCI contusion group. These results indicate that (1) mild injuries retaining weight-bearing locomotion that should have mild, if any, edema/loss of vascular tone still exhibit severe polyuria, and (2) step training was unable to reduce post-SCI polyuria. Taken together, these results indicate that the current mechanistic hypothesis of post-SCI polyuria may be incomplete.
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Journal of neurotrauma · Oct 2012
Acetylcholinesterase inhibition interacts with training to reverse spatial learning deficits after cortical impact injury.
Cholinergic mechanisms are known to play a key role in cognitive functions that are profoundly altered in traumatic brain injury (TBI). The present investigation was designed to test the ability of continuous administration, starting at the time of injury, of physostigmine (PHY), an acetylcholinesterase (AChE) inhibitor that crosses the blood-brain barrier (BBB), to ameliorate the alterations of learning and memory induced by cerebral cortex impact injury in rats under isoflurane anesthesia. Learning and memory were assessed with the Morris water maze implemented during days 7-11 (WM1), and days 21-25 post-TBI (WM2), with four trials per day for 3 days, followed by target reversal and 2 additional days of training. ⋯ In WM2 tests, PHY improved within- and between-sessions performance at both dose levels. We found that continuous AChE inhibition interacted with repeated training on the water maze task to completely reverse the deficits seen in learning and memory induced by TBI. The PHY treatment also reduced the amount of brain tissue loss as measured using cresyl violet staining.
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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.