Journal of neurotrauma
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Journal of neurotrauma · Jul 2013
Hypothermia and pharmacological regimens that prevent overexpression and overactivity of the extracellular calcium-sensing receptor protect neurons against traumatic brain injury.
Traumatic brain injury (TBI) leads to acute functional deficit in the brain. Molecular events underlying TBI remain unclear. In mouse brains, we found controlled cortical impact (CCI) injury induced overexpression of the extracellular calcium-sensing receptor (CaSR), which is known to stimulate neuronal activity and accumulation of intracellular Ca(2+) and concurrent down-regulation of type B or metabotropic GABA receptor 1 (GABA-B-R1), a prominent inhibitory pathway in the brain. ⋯ Mild hypothermia, an established practice of neuroprotection for brain ischemia, partially but significantly blunted all of the above effects of CCI. Administration of CaSR antagonist NPS89636 mimicked hypothermia to reduce loss of brain tissue and motor functions in the CCI mice. These data together support the concept that CaSR overexpression and overactivity play a causal role in potentiating TBI potentially by stimulating excitatory neuronal responses and by interfering with inhibitory GABA-B-R signaling and that the CaSR could be a novel target for neuroprotection against TBI.
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Journal of neurotrauma · Jul 2013
Biomarkers track damage after graded injury severity in a rat model of penetrating brain injury.
The goal of this project was to determine whether biochemical markers of brain damage can be used to diagnose and assess the severity of injury in a rat model of penetrating ballistic-like brain injury (PBBI). To determine the relationship between injury magnitude and biomarker levels, rats underwent three discrete PBBI severity levels defined by the magnitude of the ballistic component of the injury, calibrated to equal 5%, 10%, or 12.5% of total rat brain volume. Cortex, cerebrospinal fluid (CSF), and blood were collected at multiple time points. ⋯ In plasma, SBDP150 was elevated at 5 min after 10% PBBI and at 6 h after 12.5% PBBI. UCH-L1 levels in plasma were elevated acutely at 5 min post-injury reflecting injury severity and rapidly decreased within 2 h. Overall, our results support the conclusion that biomarkers are effective indicators of brain damage after PBBI and may also aid in the assessment of injury magnitude.
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Journal of neurotrauma · Jul 2013
Rat injury model under controlled field-relevant primary blast conditions: acute response to a wide range of peak overpressures.
We evaluated the acute (up to 24 h) pathophysiological response to primary blast using a rat model and helium driven shock tube. The shock tube generates animal loadings with controlled pure primary blast parameters over a wide range and field-relevant conditions. We studied the biomechanical loading with a set of pressure gauges mounted on the surface of the nose, in the cranial space, and in the thoracic cavity of cadaver rats. ⋯ The immunostaining against immunoglobulin G (IgG) of brain sections of rats sacrificed 24-h post-exposure indicated the diffuse blood-brain barrier breakdown in the brain parenchyma. At high blast intensities (peak overpressure of 190 kPa or more), the IgG uptake by neurons was evident, but there was no evidence of neurodegeneration after 24 h post-exposure, as indicated by cupric silver staining. We observed that the acute response as well as mortality is a non-linear function over the peak overpressure and impulse ranges explored in this work.
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Journal of neurotrauma · Jul 2013
Proton MR spectroscopy correlates diffuse axonal abnormalities with post-concussive symptoms in mild traumatic brain injury.
There are no established biomarkers for mild traumatic brain injury (mTBI), in part because post-concussive symptoms (PCS) are subjective and conventional imaging is typically unremarkable. To test whether diffuse axonal abnormalities quantified with three-dimensional (3D) proton magnetic resonance spectroscopic imaging (¹H-MRSI) correlated with patients' PCS, we retrospectively studied 26 mTBI patients (mean Glasgow Coma Scale [GCS] score of 14.7), 18- to 56-year-olds and 13 controls three to 55 days post-injury. All were scanned at 3 Tesla with T1- and T2-weighted MRI and 3D ¹H-MRSI (480 voxels over 360 cm³, ∼30% of the brain). ⋯ The PCS-positive patients (n=15) had lower WM NAA than the controls (n=12; 7.0 ± 0.6 versus 7.9 ± 0.5mM; p=0.0007). Global WM NAA, therefore, showed sensitivity to the TBI sequelae associated with common PCS in patients with mostly normal neuroimaging, as well as GCS scores. This suggests a potential biomarker role in a patient population in which objective measures of injury and symptomatology are currently lacking.
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Journal of neurotrauma · Jul 2013
Triage of children with moderate and severe traumatic brain injury to trauma centers.
Outcomes after pediatric traumatic brain injury (TBI) are related to pre-treatment factors including age, injury severity, and mechanism of injury, and may be positively affected by treatment at trauma centers relative to non-trauma centers. This study estimated the proportion of children with moderate to severe TBI who receive care at trauma centers, and examined factors associated with receipt of care at adult (ATC), pediatric (PTC), and adult/pediatric trauma centers (APTC), compared with care at non-trauma centers (NTC) using a nationally representative database. The Kids' Inpatient Database was used to identify hospitalizations for moderate to severe pediatric TBI. ⋯ Multiple regression analyses showed receipt of care at a trauma center was associated with age and polytrauma. We concluded that almost 84% of children with moderate to severe TBI currently receive care at a Level I or Level II trauma center. Children with trauma to multiple body regions in addition to more severe TBI are more likely to receive care a trauma center relative to a NTC.