Childhood Tumors
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Neuronal Responses to Injury | ||
Wallerian Degeneration – breakdown of axon distal to injury | ||
Central Chromatolysis – neuronal cell body clearing proximal to injury (may be reversible) | ||
Retrograde Degeneration – neuron undergoes atrophy when the distal axon is damaged | ||
Trans-synaptic Degeneration – neuron undergoes atrophy when main synaptic input is lost | ||
Causes of Neuronal injury: anoxic/ischemic, excitotoxicity, apoptosis, metabolic storage disease | ||
Demyelination: (stain black with Marchi’s or Sudan Black; unstained with Weigert-Pal or Loyez) Primary – specific destruction of myelin (precedes axon damage) Secondary – follows nerve cell death and axon destruction |
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CELL
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IMMUNOHISTOCHEMISTRY
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REACTION TO INJURY
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Neuron | Neurofilament, Synaptophysin, NSE | Central chromatolysis, Wallerian degeneration, neuronopathy, retrograde degeneration, Trans-synaptic degeneration, Ischemia |
Astrocyte | GFAP, Vimentin | Proliferation, Hypertrphy (gemistocyte), Gliosis |
Oligodendrocyte | Leu 7, galactocerebroside | Swelling, Proliferation |
Ependyma | Weak GFAP | Atrophy, Loss (granular ependymitis) |
Microglia | B cell and Macrophage markers | Proliferation, microglial nodule, rod cell shape |