Term
| epidemiologic risk factors for multiple sclerosis |
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Definition
1. peak age of incidence is 20-40 yrs
2. women more commonly affected 2:1
3. more common in people who live(d) in a temperate zone up until age 15 |
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Term
| genetics of multiple sclerosis |
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Definition
genetic predisposition
gene linkages: HLA DR2 and polymorphisms of IL-2 and IL-7 receptor genes |
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Term
| immunology of multiple sclerosis |
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Definition
1. oligoclonal IgG in CSF
2. antibodies to myelin and oligodendroglia
3. T-cells react against myelin in vitro |
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Term
| immune response during plaque formation |
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Definition
1. activated T-cells and monocytes leave blood vessels and accumulate in brain tissue and perivascular spaces
2. damage tissue directly or through secretion of pro-inflammatory cytokines |
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Term
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Definition
| alters cytokine production and favors anti-inflammatory differentiation of T-cells |
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Term
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Definition
| prevents migration of inflammatory cells out of blood vessels |
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Term
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Definition
1. decrease in tissue density
2. loss of oligodendrocytes
3. mostly reactive astrocytes |
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Term
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Definition
| myelin stops abruptly - plaque is sharply demarcated |
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Term
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Definition
preservation of some axons - major event is removal of myelin and oligodendroglial cells
axons are distorted and dented by presence of macrophages - function can return after inflammatory response ends |
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Term
| findings in demarcation zone |
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Definition
demarcation zone is filled with T-cells and oligos attempting to remylinate
macrophages are sharply cut off at demarcation zone |
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Term
| Perivascular demyelination |
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Definition
1. plaques tend to follow teh course of small veins and do not respect tract boundaries
2. perivascular lymphocytes in young plaque reflect an immune reaction
3. may impair venous outflow
4. perivascular space infiltration by monocytes and macrophages
5. monocytes have receptors for TNFalpha |
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Term
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Definition
1. lesions may extend into gray matter
2. U fibers in cerebrum not spared
3. periventricular common, and the corpus callosum is a common target |
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Term
| evolution of enhancing lesion on MRI |
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Definition
hyperintense region to a blackhole
breakdown of BBB allows gadolinium enhancement |
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