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3691298 
Technical Report 
Organophosphate-related alterations in myelin and axonal transport in the living mammalian brain 
Terry, AV 
2013 
U.S. Army Medical Research and Materiel Command 
Fort Detrick, MD 
English 
Annual rept. 30 Sep 2012-29 Sep 2013.
The original document contains color images.
The overall goal of this project is to determine the underlying mechanisms for the neurological symptoms associated with Gulf War Illness. The central hypothesis is that subthreshold exposures to organophosphates-OPs (defined as exposures not associated with acute signs of toxicity) may have adversely affected axonal transport and/or myelin integrity in affected individuals. We are studying two OPs, a representative insecticide that was used in the first gulf war, chlorpyrifos (CPF), and a representative, nerve agent, diisopropylfluorophosphate (DFP) in rats. The first year of this proposal has been dedicated to Specific Aim No. 1: which has been designed to evaluate OP effects on axonal transport in the living rat brain using manganese-enhanced magnetic resonance imaging (MEMRI) of the optic nerve axonal projections from the retina to the superior colliculus. The following procedures have been conducted to date (N=4-6): (1) baseline MRI scans; (2) daily injections of vehicle or chlorpyrifos (3.0-18.0 mg/kg) x 14 days; (3) a second MRI scan on the day following the last drug injection; (4) a third scan after a 4 week (OP-free) washout period. For each animal, a separate 6 hour and 24 hour scan was performed after Mg2+ eye injection. The data analyzed to date appear to support our hypothesis that repeated OP exposure leads to persistent impairments in axonal transport in the brain of living animals. 
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