Types of traumatic CNS injury

Focal injuries result from direct loading and can often occur without widespread, or diffuse, damage. Focal injuries are typically induced when an object penetrates the skull or vertebral column as a result of a motor vehicle accident, gunshot wound, or a blow. As a result, macroscopically visible damage is typically visible at the site of impact, and the clinical symptoms are often very specific to the area that is directly injured. Focal injuries to the brain include epidural hematomas and...

Current concepts of cerebral oxygen transport and energy metabolism after severe traumatic brain injury

Amelink1 and J.P. Muizelaar2 1 Rudolf Magnus Institute of Neuroscience, Department of Neurosurgery, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands 2Department of Neurosurgery, University of California at Davis Medical Center, 4860 Y Street, Suite 3740, Sacramento, Abstract Before energy metabolism can take place, brain cells must be supplied with oxygen and glucose. Only then, in combination with normal mitochondrial function,...

Traumatic mechanical insults

Loads are described as direct (e.g., physical contact between the head and another object) or indirect (e.g., as the result of motion of the head). In indirect loading, acceleration of the second body (e.g., the head) can act analogously to applied forces. Loads can be translational (linear), rotational, or angular (a combination of translational and rotational). The type of force and the direction, or plane, of loading, will also affect the resulting mechanical response in the tissue. The...

Revisiting and revising the Classical View of astrocytes in CNS trauma

As discussed in the introduction, TBI research to date has focused mainly on neuroprotection and given little consideration to the role of glial cells in injury. This has significant implications for the understanding of brain pathology after TBI since the population of glial cells in brain is actually much larger than neurons. Furthermore, the importance of the complex communication and interaction between astrocytes and neurons described above are becoming more apparent in normal brain...

Info

Schematic showing the relation between CBF and ischemic duration tissue infarction. (Adapted with permission from Jones et al., 1981.) Fig. 1. Schematic showing the relation between CBF and ischemic duration tissue infarction. (Adapted with permission from Jones et al., 1981.) arterio venous difference of oxygen (AVDO2) of (13-6.7) 6.3 vol (ml of 02 100ml of blood). Knowing how much blood is flowing to the brain ( 50ml 100g brain tissue min) and how much oxygen the brain extracts from...

Acute astrocyte loss following CNS insult

Astrocyte swelling is a prominent feature of both cerebral ischemia (Jenkins et al., 1982) and TBI (Castejon, 1998) and is considered to be an exaggerated extension of normal astrocyte function'' (Kimelberg, 1992). Astrocyte swelling is likely a prominent component of raised ICP after both ischemia and TBI and resulting in part from alterations in ion-transport mechanisms that leads to osmotically obligated water entry (Kimelberg et al., 1990). Cortical biopsies of human TBI complicated with...

Pvi

Normal PVI is 20-25 ml (Shapiro et al., 1980). However PVI has been observed as low as 6 ml after severe head injury, which indicates that in going from normoventilation (PaCO2 30 mm Hg) to strong hyperventilation (PaCO2 18 mm Hg) resulting in vasoconstriction, ICP could theoretically be decreased tenfold (Bouma et al., 1992a). (That this is not always desirable may be clear from the following example PaCO2 36 mm Hg, ICP 40 mm Hg, MABP 100 mm Hg, CBF 30 ml 100 g min AVDO2 6vol - CMRO2 1.8 ml...

References

Ackery, A., Tator, C. and Krassioukov, A. (2004) A global perspective on spinal cord injury epidemiology. J. Neurotrauma, 21 1355-1370. Attewell, R.G., Glase, K. and McFadden, M. (2001) Bicycle helmet efficacy a meta-analysis. Accid. Anal. Prev., 33 345-352. Berkowitz, M., O'Leary, P., Kruse, D. and Harvey, C. (1998) Spinal cord injury an analysis of medical and social costs. Demos Medical Publishing Inc., New York. Bigler, E. (2001) The lesion(s) in traumatic brain injury implications for...

Response phases of traumatic CNS injury Acute cellular response

Infinite Horizon Impactor

The initial damage that is a direct result of loading to the brain is defined as the primary phase of injury. Biomechanicians study this phase in order to determine tissue tolerances to mechanical loading because the effects of the mechanical insult can be more easily isolated from biochemical events occurring in the secondary or more chronic phase. Our understanding of tolerances at the cellular level is vital to developing better safety equipment and understanding mechanotransduction in the...

Role of glutamate in astrocyte pathology in CNS trauma

During normal neuronal activity extracellular glutamate in the synaptic cleft must be rapidly cleared to optimize the signal-to-noise ratio as well as to prevent neuronal damage from excitotoxic-ity. Glutamate is removed from the synapse by glutamate transporters located in the plasma membrane of neurons and adjacent astrocytes Kanner and Schuldiner, 1987 . The major glutamate removal mechanism is through the astrocyte-specific sodium-dependent glutamate transporters, GLT-1 and GLAST Danbolt,...

NMDAR are the most commonly studied mechanoactivated target

Alterations in ionic homeostasis have been observed across nearly all in vitro and in vivo models of TBI and therefore provide a natural starting point for identifying mechanoactivated receptors. Due to the role of glutamate receptors in both physiologic learning and memory and pathologic stroke and epilepsy conditions, N-methyl D-aspartate receptors NMDAR are among the most widely studied receptors responsible for the cytosolic calcium overload Gagliardi, 2000 Arundine and Tymianski, 2004 ....

List of Contributors

Michael's Hospital, Trauma Research, Toronto, ON M5B 1W8, Canada G.J. Amelink, Rudolf Magnus Institute of Neuroscience, Department of Neurosurgery, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands A.J. Baker, St. Michael's Hospital, Trauma Research, Toronto, ON M5B 1W8, Canada D.C. Baptiste, Division of Cellular and Molecular Biology, Toronto Western Research Institute and Krembil Neuroscience Centre, Toronto Western Hospital, 12th Floor Room...