Articles: brain-injuries.
-
Journal of neurotrauma · Oct 1994
Different cerebral hemodynamic responses following fluid percussion brain injury in the newborn and juvenile pig.
The present study was designed to characterize the influence of early developmental changes on the relationship among systemic arterial pressure, cerebral hemodynamics, and cerebral oxygenation during the first 3 h following percussion brain injury. Anesthetized newborn (1-5 days old) and juvenile (3-4 weeks old) pigs equipped with a closed cranial window were connected to a percussion device consisting of a saline-filled cylindrical reservoir with a metal pendulum. Brain injury of moderate severity (1.9-2.3 atm) was produced by allowing the pendulum to strike a piston on the cylinder. ⋯ These data show that the effects of comparable brain injury level were very different in newborn and juvenile pigs. Further, these data suggest that reductions in cerebral blood flow following brain injury are more dependent on changes in reactivity of arterioles. Finally, these data suggest that the decrease in cerebral oxygenation, an index of metabolism, coupled with reduced cerebral blood flow, could result in profound hypoperfusion after brain injury.
-
Journal of neurotrauma · Oct 1994
Modification of the cortical impact model to produce axonal injury in the rat cerebral cortex.
Diffuse axonal injury (DAI) is a form of brain injury that is characterized by morphologic changes to axons throughout the brain and brainstem. Previous biomechanical studies have shown that primary axonal dysfunction, ranging from minor electrophysiologic disturbances to immediate axotomy, can be related to the rate and level of axonal deformation. Some existing rodent head injury models display varying degrees of axonal injury in the forebrain and brainstem, but the extent of axonal damage in the forebrain has been limited to the contused hemisphere. ⋯ Neurofilament immunohistochemistry revealed numerous axonal retraction balls in the subcortical white matter and overlying deep cortical layers in the right hemisphere beneath the contralateral craniotomy. Retraction balls were not seen at these positions in normals, sham controls, or animals that received cortical impact without contralateral craniotomy and dural opening. The results from these physical modeling and animal experiments indicate that opening of the contralateral dura mater permits translation of sufficient mechanical deformation across the midline to produce a more widespread pattern of axonal injury in the forebrain, a pattern that is distinct from those produced by existing fluid percussion and cortical impact techniques.
-
Journal of neurotrauma · Oct 1994
Neurofilament 68 and neurofilament 200 protein levels decrease after traumatic brain injury.
We have examined the effect of lateral cortical impact injury on the levels of axonal cytoskeletal proteins in adult rats. Traumatic brain injury (TBI) causes a significant decrease in the protein levels of two prominent neurofilament (NF) proteins, NF68 and NF200. We employed quantitative immunoreactivity measurements on Western blots to examine NF68 and NF200 levels in homogenates of hippocampal and cortical tissue taken at several intervals postinjury. ⋯ This NF68 antigenicity pattern suggests the production of NF68 breakdown products caused by the pathologic activation of neuronal proteases, such as calpain. Putative NF68 breakdown products increase significantly until 1 day postinjury, suggesting that NF degradation may be ongoing until that time and indicating that a potential therapeutic window may exist within the first 24 h postinjury. In summary, these data identify specific biochemical alterations of the neuronal cytoskeleton following TBI and lay a foundation for further investigation of postinjury cytoskeletal changes in neuronal processes.
-
Neurosurg. Clin. N. Am. · Oct 1994
ReviewIntegrated multimodality monitoring in the neurosurgical intensive care unit.
The selection of variables for continuous monitoring in the neurosurgical intensive care unit is based upon the requirement for constant perfusion and oxygenation of the brain and knowledge of the frequency and prognostic significance of abnormal values. Both arterial and intracranial pressure must be considered in the form of cerebral perfusion pressure. Body temperature and arterial oxygen saturation are essential to monitoring. Measurement of jugular venous oxygen saturation and cerebral blood flow velocity provide information of value in determining the source of raised intracranial pressure, the most appropriate means of treating it, and the safety of therapy.
-
The sources of fever and infection in neurosurgical patients in the intensive care unit are varied and complex. Benign postoperative fever due to atelectasis of the lungs or from central nervous system sources are difficult to define. Distinguishing between these "benign" sources and true nosocomial bacterial infections can be a difficult clinical process. Empiric antibiotic regimens are outlined, and some guidelines are proposed for the management of infected catheters.