Multiple sclerosis : clinical and laboratory research
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Rising multiple sclerosis incidence over the last 50 years and geographic patterns of occurrence suggest an environmental role in the causation of this multifactorial disease. Design options for epidemiological studies of environmental causes of multiple sclerosis are limited by the low incidence of the disease, possible diagnostic delay and budgetary constraints. We describe scientific and methodological issues considered in the development of the Australian Multicentre Study of Environment and Immune Function (the Ausimmune Study), which seeks, in particular, to better understand the causes of the well-known MS positive latitudinal gradient. ⋯ Cases are persons with an incident first demyelinating event (rather than prevalent multiple sclerosis), sourced from a population base using a two tier notification system. Controls, matched on sex, age (within two years) and region of residence, are recruited from the general population. Biases common in case-control studies, eg, prevalence-incidence bias, admission-rate bias, non-respondent bias, observer bias and recall bias, as well as confounding have been carefully considered in the study design and conduct of the Ausimmune Study.
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Controlled Clinical Trial
Optic nerve magnetization transfer imaging and measures of axonal loss and demyelination in optic neuritis.
Magnetization transfer imaging is an MRI technique that provides quantitative information about in vivo tissue integrity, including myelin and axonal content, and is expressed as the magnetization transfer ratio (MTR). The optic neuritis lesion can model the MS lesion in vivo and permits use of non-invasive markers of optic nerve myelination (visual evoked potential [VEP] latency) and retinal neuroaxonal loss (optical coherence tomography [OCT]) to provide further information about the in vivo substrates of optic nerve MTR. Twenty-five patients with optic neuritis were studied using an optic nerve MTR sequence, quantitative visual function testing, VEPs and OCT, along with 15 controls. ⋯ OCT-quantified retinal neuroaxonal loss also correlated with MTR. In conclusion, markers of optic nerve myelination and axonal loss both correlate with optic nerve MTR. Because axonal loss following optic neuritis also results in myelin loss, the relative contributions of the two pathological conditions to the MTR measures cannot be estimated from this study.
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Clinical Trial
Deep grey matter "black T2" on 3 tesla magnetic resonance imaging correlates with disability in multiple sclerosis.
T2 hypointensity (black T2, BT2) in the deep grey matter of multiple sclerosis (MS) patients correlate weakly with disability at 1.5 T. BT2 is likely to be caused by abnormal iron deposition. ⋯ We observed a significant correlation between expanded disability status scale and signal intensity on 3 T MRI in the globus pallidus and the caudate nucleus (r = -0.5, P < 0.05). BT2 at 3 T may be a useful MRI measure associated with disability in MS and warrants further study.