Previous attempts to reproduce striatonigral degeneration, the core pathology underlying Parkinsonism in multiple system atrophy, have been impeded by interactions in the neurotoxins used to ...replicate striatal and nigral degeneration in rodents. To overcome these interactions, we have developed a new model of striatonigral degeneration which uses a single unilateral administration of 1-methyl-4-phenylpyridinium ion (MPP
+) into the rat striatum. Spontaneous and drug-induced rotational behaviour, thigmotactic scanning, stepping adjusting steps and paw reaching deficits were compared in four groups of animals: group 1 (control), group 2 (20 μg quinolinic acid), group 3 (20 μg 6-hydroxydopamine), and group 4 (90 nmol MPP
+). MPP
+ administration resulted in the absence of the amphetamine-induced ipsilateral bias observed in the 6-hydroxydopamine group and of the apomorphine-induced ipsilateral bias observed in the quinolinic acid group. There was no thigmotactic scanning asymmetry in the MPP
+-injected rats compared to the quinolinic acid- and the 6-hydroxydopamine-injected rats. MPP
+ elicited a bilateral stepping adjustment deficit similar to that found in the quinolinic acid group when compared to controls. MPP
+ also elicited a more severe and significant contralateral deficit in paw reaching compared to controls, 6-hydroxydopamine and quinolinic acid groups. Histopathology revealed a significant reduction of the lesioned striatal surface (−47.53%) with neuronal loss and increased astrogliosis in the MPP
+ group grossly similar to that found in the quinolinic acid group. Contrary to the latter group, however, loss of intrastriatal and striatal-crossing fibre bundles was observed in the MPP
+ group as there was also some retrograde degeneration in the ipsilateral thalamic parafascicular nucleus. The mean loss of dopaminergic cells in the ipsilateral substantia nigra pars compacta in MPP
+ rats was less marked (−48.8%) than in the 6-hydroxydopamine rats (−63.6%) and was not significant in quinolinic acid rats (−5.2%).
This study shows that a single unilateral intrastriatal administration of MPP
+ induces a unique motor behaviour resulting from both nigral and striatal degeneration, but also from possible extrastriatal damage. This ‘single toxin–double lesion’ paradigm may thus serve as a rat model of striatonigral degeneration.
Context. The Planck satellite was successfully launched on May 14th 2009. We have completed the pre-launch calibration measurements of the High Frequency Instrument (HFI) on board Planck and their ...processing. Aims. We present the results ot the pre-launch calibration of HFI in which we have multiple objectives. First, we determine instrumental parameters that cannot be measured in-flight and predict parameters that can. Second, we take the opportunity to operate and understand the instrument under a wide range of anticipated operating conditions. Finally, we estimate the performance of the instrument built. Methods. We obtained our pre-launch calibration results by characterising the component and subsystems, then by calibrating the focal plane at IAS (Orsay) in the Saturne simulator, and later from the tests at the satellite level carried out in the CSL (Liège) cryogenic vacuum chamber. We developed models to estimate the instrument pre-launch parameters when no measurement could be performed. Results. We reliably measure the Planck-HFI instrument characteristics and behaviour, and determine the flight nominal setting of all parameters. The expected in-flight performance exceeds the requirements and is close or superior to the goal specifications.
Most observations of the solar corona beyond 2 Rs consist of broadband visible light imagery from coronagraphs. The associated diagnostics mainly consist of kinematics and derivations of the electron ...number density. While the measurement of the properties of emission lines can provide crucial additional diagnostics of the coronal plasma (temperatures, velocities, abundances, etc.), these observations are comparatively rare. In visible wavelengths, observations at these heights are limited to total eclipses. In the VUV range, very few additional observations have been achieved since the pioneering results of UVCS. One of the objectives of the Full Sun Imager (FSI) channel of the EUI telescope on board the Solar Orbiter mission has been to provide very wide field-of-view EUV diagnostics of the morphology and dynamics of the solar atmosphere in temperature regimes that are typical of the lower transition region and of the corona. FSI carries out observations in two narrowbands of the EUV spectrum centered on 17.4 nm and 30.4 nm that are dominated, respectively, by lines of Fe IX/X (formed in the corona around 1 MK) and by the resonance line of He II (formed around 80 kK in the lower transition region). Unlike previous EUV imagers, FSI includes a moveable occulting disk that can be inserted in the optical path to reduce the amount of instrumental stray light to a minimum. FSI detects signals at 17.4 nm up to the edge of its FOV (7~Rs), which is about twice further than was previously possible. Comparisons with observations by the LASCO and Metis coronagraphs confirm the presence of morphological similarities and differences between the broadband visible light and EUV emissions, as documented on the basis of prior eclipse and space-based observations. The very-wide-field observations of FSI are paving the way for future dedicated instruments.
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