NR AXQD
AU Konold,T.; Bone,G.E.; Sicilia,A.S.; Spiropoulos,J.
TI Flash Visual Evoked Potential Recordings Reveal No Evidence of Visual Impairment in Bovine Spongiform Encephalopathy
QU International Conference - Prion 2007 (26.-28.9.2007) Edinburgh International Conference Centre, Edinburgh, Scotland, UK - Book of Abstracts: Pathology and Pathogenesis P03.156
IA http://www.prion2007.com/pdf/Prion Book of Abstracts.pdf
PT Konferenz-Poster
AB
Background: Disease-associated prion protein has been detected in the visual pathways of sheep with natural scrapie and human patients suffering from sporadic or variant Creutzfeldt-Jakob disease. In addition, bovine spongiform encephalopathy (BSE)-sensitive transgenic mice challenged with retina and optic nerve from a terminally diseased cow with BSE have succumbed to disease. Over-reactivity to visual stimuli is also a common clinical feature of BSE. This suggests that the visual pathways are affected by spongiform encephalopathies, which could be assessed clinically by measuring flash visual evoked potentials (FVEP).
Objective: To determine if BSE causes abnormalities in the visual pathways that could be detected by measuring FVEP.
Material and Methods: As part of a pilot study, FVEP were recorded from 16 adult Friesian steers from an experimental BSE study where steers were orally dosed with various single doses of BSE brainstem homogenate: Six steers displayed neurological signs consistent with BSE and with confirmation of the disease by immunohistochemistry and Western immunoblot, six were culled due to intercurrent diseases without confirmation of the disease, and four were control cattle, either unchallenged environmental controls (n=3) or orally challenged with BSE-free brain (n=1). Animals were not sedated during the recording. The stimuli were flashes of white light at 1.5 Hz, and one hundred evoked responses were averaged twice for each eye. The latencies of the positive and negative peaks (P1-3 and N1-2) and the corresponding amplitudes were determined.
Results: The generated waveforms were highly variable between individual cattle. The differences in the peak latencies and amplitudes between steers affected by BSE and all steers without pathological confirmation or control cattle only were statistically not significant (P>0.05, Mann-Whitney U test).
Conclusion: A dysfunction of the visual pathways in cattle with BSE was not evident when based on single measurements of FVEP. The high variability of waveforms makes interpretation very difficult but may be overcome if repeated measurements are taken during the course of the disease.
AD T. Konold, G.E. Bone, J. Spiropoulos, Veterinary Laboratories Agency Weybridge, Neuropathology, UK; A.S. Sicilia, Veterinary Laboratories Agency Weybridge, Molecular Pathogenesis and Genetics, UK
SP englisch
PO Schottland