Articles: brain-injuries.
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Journal of neurotrauma · May 2000
Three months of chronic ethanol administration and the behavioral outcome of rats after lateral fluid percussion brain injury.
This study examined the effects of 3 months of chronic ethanol administration (CEAn) on the behavioral outcome in rats after lateral fluid percussion (FP) brain injury. Rats were given either an ethanol liquid diet (ethanol diet groups) or a pair-fed isocaloric sucrose control diet (control diet groups) for 3 months. Then, rats from both diet groups were subjected to either lateral FP brain injury of moderate severity (1.8 atm) or to sham operation. ⋯ However, a trend towards cognitive impairment in the sham animals and a trend towards reduced deficits in the brain-injured animals were observed in the ethanol diet group. Histologic analysis of injured animals from both diet groups revealed similar extents of ipsilateral cortical and hippocampal CA3 damage. These results, in general, suggest that 3 months of CEAn does not significantly alter the behavioral and morphologic outcome of experimental brain injury.
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Journal of neurotrauma · May 2000
ReviewGender differences in acute CNS trauma and stroke: neuroprotective effects of estrogen and progesterone.
Increasing evidence has demonstrated striking sex differences in the pathophysiology of and outcome after acute neurological injury. Lesser susceptibility to postischemic and posttraumatic brain injury in females has been observed in experimental models. Additional evidence suggests this sex difference extends to humans as well. ⋯ Progesterone, on the other hand, has a membrane stabilizing effect that also serves to reduce the damage caused by lipid peroxidation. In addition, it may also provide neuroprotection by suppressing neuronal hyperexcitability. The following review will discuss experimental and clinical evidence for sex differences in outcome after acute brain trauma and stroke, review the evidence implicating estrogens and progestins as mediators of this neuroprotection following acute neurological injury, and finally, address the specific mechanisms by which these hormones may protect the brain following acute neurological injury.
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Journal of neurotrauma · May 2000
Astrocytes generate isoprostanes in response to trauma or oxygen radicals.
Previous studies have shown that oxygen radical scavengers prevent the reduced cerebral blood flow that occurs following experimental traumatic brain injury. The exact chemical species responsible for the posttraumatic reduction in flow is unknown. We tested whether isoprostanes, which are formed by non-cyclooxygenase-dependent free radical attack of arachidonic acid and are vasoconstrictors of the cerebral circulation, are increased in astrocytes following stretch-induced trauma or injury with a free radical generating system. ⋯ The hydroxyl generating system caused free and cell-bound isoprostanes to increase to more than 400% of control. After trauma, free and membrane bound isoprostanes increased to 321 +/- 34% and 229 +/- 23% of control, respectively, and posttraumatic increases were prevented by deferoxamine. Since astrocytes are in close proximity to cerebral vessels, posttraumatic free radical formation may increase the formation of isoprostanes, which in turn produce vasoconstriction and decrease cerebral blood flow.
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Am. J. Respir. Crit. Care Med. · May 2000
Implications of extubation delay in brain-injured patients meeting standard weaning criteria.
We hypothesized that variation in extubating brain injured patients would affect the incidence of nosocomial pneumonia, length of stay, and hospital charges. In a prospective cohort of consecutive, intubated brain-injured patients, we evaluated daily: intubation status, spontaneous ventilatory parameters, gas exchange, neurologic status, and specific outcomes listed above. Of 136 patients, 99 (73%) were extubated within 48 h of meeting defined readiness criteria. ⋯ Median hospital charges were $29,057.00 higher for extubation delay patients (p < 0.001). This study does not support delaying extubating patients when impaired neurologic status is the only concern prolonging intubation. A randomized trial of extubation at the time brain-injured patients fulfill standard weaning criteria is justifiable.
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Journal of neurotrauma · May 2000
Microdialysis-based long-term measurements of energy-related metabolites in the rat brain following a fluid percussion trauma.
The aim of the study was to evaluate an experimental approach based on a fluid percussion rat trauma model in combination with the microdialysis technique for the analysis of cerebral interstitial biochemical alterations following head trauma, and to test the hypothesis that the previously observed acute accumulation of lactate and increase in the lactate pyruvate ratio may persist for several days following trauma. We analyzed how lactate, pyruvate, and glucose were altered in the cortex adjacent to the contusion and in the contralateral side of the brain following a traumatic brain injury. The results were compared with those from sham-operated animals. ⋯ We conclude that the previously observed acute alterations in brain metabolism persist for at least 48 h posttrauma. Further, the measured parameters from the contralateral side can be used as controls since they did not differ from the sham group. Combining microdialysis with a fluid percussion trauma model may be a tool to explore secondary brain injury mechanisms and evaluate new therapies for the treatment of traumatic brain injury.