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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Identification of defects in specific parallel #channels' of the human visual system

Wolf, Janet Elizabeth January 1996 (has links)
No description available.
2

Temporal processing in the normal and demyelinated human visual pathway

Edgar, Graham K. January 1988 (has links)
No description available.
3

Interferons in multiple sclerosis and optic neuritis

Salonen, Reijo. January 1983 (has links)
Thesis (doctoral)--University of Turku. / Includes reprints of 5 articles on which thesis is based.
4

Visual psychophysics and magnetic resonance imaging in demyelinating disease of the visual system

Caruana, P. January 1997 (has links)
No description available.
5

Human disorder of energy transduction : molecular pathology

Malik, Safarina Golfiani, 1963- January 2001 (has links)
Abstract not available
6

A qualitative and quantitative magnetic resonance diffusion study investigating the pathogenesis of cryptococcal-induced visual loss.

Moodley, Anandan A. 28 May 2014 (has links)
Background: Cryptococcal induced visual loss is common and increasingly becoming a debilitating consequence in survivors of cryptococcal meningitis (CM). Conflicting reports of the optic neuritis and papilloedema models of visual loss have delayed the introduction of effective interventional strategies for prevention and treatment of visual loss in CM. Qualitative and quantitative diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) of the optic nerves have proven useful in the examination of the microstructure of the optic nerve especially in optic neuritis. Its application has been extrapolated to other optic nerve disorders such as ischaemic optic neuropathy and glaucoma. The aim of this study is to elucidate the pathogenesis of cryptococcal-induced visual loss using diffusion imaging of the optic nerve as an investigational tool. Method: Full ethical approval was obtained from the Greys Hospital, Department of Health and University of KwaZulu Natal Ethics Committees. Reliable and reproducible optic nerve diffusion techniques were first developed and optimized on 29 healthy volunteers at Greys Hospital, Neurology and Radiology departments using a Philips 1.5 Tesla Gyroscan. Informed consent was also obtained from 95 patients suffering from CM (≥18 yrs. of age), 14 patients with papilloedema and 14 patients with optic neuritis from other causes, recruited from Greys and Edendale Hospitals. Patients underwent full neuro-ophthalmological assessments, CSF examination, haematological workup, CD4 count, (viral load for some), electrophysiological assessment of vision [Visual evoked potential (VEP) and Humphreys visual fields (HVF)], Magnetic Resonance Imaging (MRI) scan of the brain and orbits and DWI and DTI of the optic nerves. Results and Discussion: Visual loss is common in CM, occurring in 34.6-48%. Optic neuritis was uncommon as evidenced by a lack of signal change and lack of enhancement within the optic nerve in all patients scanned. The peri-optic CSF space was not dilated and the optic nerve diameter was not increased regardless of CSF pressure and visual status. Swollen optic discs occurred in only 25% of patients whereas raised intracranial pressure (> 20cmCSF) was demonstrated in 69-71% of patients. Therefore visual loss could not be explained by papilloedema alone. The VEP P100 latency was shown to be a useful screening test for subclinical optic nerve disease in CM, but HVF was not. The optic nerve diffusion imaging used was reliable and reproducible and produced diffusion parameters equivalent to other investigators in the field. Neither optic nerve movement nor the CSF signal was demonstrated to impact significantly on optic nerve diffusion parameters. Optic nerve diffusion imaging did not demonstrate similarities between CM and papilloedema or optic neuritis regardless of CSF pressure or vision. Conclusion: The rarity of optic neuritis in CM and the disparity between papilloedema and visual loss together with the lack of support from diffusion studies suggest a 3rd mechanism of visual loss viz. the optic nerve compartment syndrome. Good clinical support is provided by a case report for this hypothesis that shows re-opening of the peri-optic CSF space and return of the peri-optic CSF signal on MRI with lowering of intracranial pressure and antifungal treatment. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2013.
7

The therapeutic effect of LIF in EAE-associated axonal injury /

Alexandrou, Estella. January 2009 (has links)
Thesis (MPhil)--University of Melbourne, Centre for Neuroscience, The Howard Florey Institute, 2009. / Typescript. Includes bibliographical references (leaves 137-160)
8

A phase II randomised controlled trial of amiloride as a neuroprotective treatment in optic neuritis : studying in vivo neurodegeneration, neuroprotection and cortical plasticity after an inflammatory insult to the visual system

McKee, Justin January 2017 (has links)
Basic science and early clinical trial evidence suggest the safe diuretic drug amiloride, may exert a neuroprotective effect in multiple sclerosis (MS) through blockade of the acid sensing ion channel. Neuroprotective treatments are a key unmet need in multiple sclerosis. Optic neuritis (ON) is a discrete CNS inflammatory event leading to neuro-axonal injury in the optic nerve and retina. The optic nerve is part of the visual system, one of the most functionally and structurally eloquent systems in the central nervous system, which affords a number of unique modalities to assess neurodegeneration and neuroprotection. The visual system can be classified into two parts, the anterior and posterior visual systems, which are defined by the lateral geniculate nucleus, where the two components synapse. The extent of neurodegeneration following ON in the anterior visual system can be imaged in vivo through scanning laser polarimetry (GDx) and optical coherence tomography (OCT). The posterior visual system can be imaged by quantitative and functional magnetic resonance imaging (MRI) of the brain, giving insights into white matter structural integrity and cortical plasticity over time. Combining these modalities in a longitudinal study, allows assessment of the impact of neurodegeneration in the anterior visual system on neurodegeneration downstream in the posterior visual system and on changes in functional connectivity over time in the visual cortex. Furthermore, in the clinical trial setting the neuroprotective effect of any intervention both on direct anterior neurodegeneration and downstream processes can be assessed. The functional relevance of changes in all of these biomarkers can be tested through a number of visual measures, including low contrast visual acuity. In MS, the contribution of transsynaptic neurodegeneration to the global neuronal loss experienced by patients is an area of incomplete understanding. In addition, the role of the visual cortex, through neuroplasticity, in aiding visual recovery from optic neuritis, is unclear. To address these issues, this thesis reports the results of the first clinical trial of amiloride in ON, and shows that despite the pre- and early clinical evidence of neuroprotection of amiloride, no neuroprotective benefit was found. It goes on to explore reasons for this lack of effect including the finding of early retinal neurodegeneration in ON, and the need for early recruitment windows in the future. From there, it makes a detailed assessment of the longitudinal changes in retinal OCT for 12 months following ON, including a novel finding of the temporal evolution of inner nuclear layer swelling, previously reported only cross-sectionally. Next, for the first time macular retinal neurodegeneration is shown to influence diffusion tensor MRI derived measures of white matter integrity in the optic radiations, indicating transsynaptic neurodegeneration. Finally, longitudinal changes in resting state functional connectivity following ON are found in the visual system for the first time. The interaction between this cortical functional, retinal neurodegeneration and visual recovery is probed.
9

Autonomic dysfunction in multiple sclerosis and optic neuritis

Saari, A. (Anne) 10 August 2010 (has links)
Abstract Multiple sclerosis (MS) is one of the major causes of disability in the young, mostly affecting people between 20–45 years of age. MS is considered as an autoimmune disorder, characterized by discrete areas of central nervous system inflammation, demyelination and axonal injury. Symptoms related to alterations of the autonomic nervous system are frequent in patients with MS. Bladder dysfunction or impairment of sexual performance is highly distressing for most MS patients, whereas the clinical relevance of other autonomic symptoms is less clear. The present study was designed to clarify the involvement of cardiovascular and sudomotor dysfunctions in patients with MS, to study the sudomotor functions in patients with optic neuritis (optic neuritis being a frequent initial manifestation of MS), and to assess the extent of demyelinative lesions in the CNS by using magnetic resonance imaging and by correlating the findings thus obtained with autonomic nervous system responses. The study showed cardiovascular autonomic regulation failure in MS patients manifesting itself both in the heart rate responses to deep breathing and in the heart rate and blood pressure responses in the tilt table test. In particular, midbrain lesions were found to be associated with cardiovascular dysfunction. MS patients also showed abnormal sympathetic skin responses indicating sudomotor failure. Focal MS lesions in the temporal lobe, in the pons and in the cerebellum were also associated with abnormal sympathetic skin responses. MS patients were also found to have an impairment in thermoregulatory sweating, which seemed to be related to disease severity and to total lesion volume in the brain. Sympathetic skin responses were also abnormal in optic neuritis patients, suggesting sudomotor autonomic failure. Patients with optic neuritis showed no thermoregulatory dysfunction.
10

Développement de biomarqueurs diagnostiques et de suivi dans les maladies inflammatoires du système nerveux central en imagerie par résonnance magnétique et tomographie par cohérence optique / Development of imaging biomarkers for diagnosis and follow-up in inflammatory diseases of central nervous system using Magnetic Resonance Imaging and Optical Coherence Tomography

Outteryck, Olivier 11 December 2015 (has links)
INTRODUCTION._Le handicap associé aux maladies inflammatoires du système nerveux central (SNC), représentées par la sclérose en plaques (SEP) et la neuromyélite optique de Devic (NMOSD), est sous-tendu par la perte neuronale._x000D_La tomographie par cohérence optique (OCT) et l'imagerie par résonance magnétique (IRM) sont des outils robustes et reproductibles permettant de mesurer la perte axonale in vivo.OBJECTIFS.Développer des biomarqueurs OCT et IRM pour le diagnostic, le pronostic et le suivi des patients atteints de maladies inflammatoires du SNC.MATERIELS et METHODES.Notre IRM est de champ magnétique 3 teslas (Achieva, Philips, Best, Pays Bas). L'appareil OCT est de 4éme génération (Heidelberg Spectralis, Allemagne). (1) Nous avons développé une séquence en tenseur de diffusion (DTI) de la moelle épinière cervicale en acquisition coronale et (2) évalué les corrélations entre les paramètres DTI et le handicap clinique d'une cohorte de patients SEP. (3) Nous avons comparé la séquence 3D-Double Inversion Récupération (DIR) à la séquence 2D-STIR FLAIR coronal pour la détection des hypersignaux inflammatoires du nerf optique.Sur le plan OCT, (4) nous avons participé à une étude multicentrique pour la validation de critères de qualité OCT. (5) Nous avons réalisé une étude OCT comparative de patients SEP, NMOSD et de sujets sains, afin de mettre en évidence des paramètres OCT différenciant les 2 maladies, parmi lesquels l'épaisseur de la pRNFL (globale ou en secteurs) et des couches maculaires (logiciel de segmentation HEYEX). (6) Nous avons évalué la longueur de l'hypersignal DIR du nerf optique comme potentiel biomarqueur de la perte axonale rétinienne évaluée en OCT.RESULTATS.(1) Les paramètres DTI (fraction d'anisotropie [FA], diffusivité moyenne [MD] et radiale [rD]) étaient significativement différents entre les sujets SEP et sains. Chez les sujets SEP, la FA diminue, la MD et la rD augmentent.(2) Dans la SEP, la FA mesurée au sein de la moelle épinière cervicale (C2-C6) était modérément corrélée au handicap clinique du patient mesuré par le score EDSS et les scores fonctionnels pyramidal, sensitif et sphinctérien._x000D_(3) La séquence 3D-DIR était plus précise que le 2D STIR FLAIR pour la détection d'un hypersignal inflammatoire du nerf optique (Se 95%, Sp 94%) et montrait une concordance inter-observateur plus élevée (kappa = 0.96).(4) La concordance inter-observateur des critères de qualité OCT OSCAR-IB était substantielle (kappa = 0.7).(5) Nous mettons en évidence une atrophie rétinienne post ON comparable entre la SEP et la NMOSD. Les patients SEP présentent une atrophie maculaire et de la pRNFL temporale sur les yeux sans névrite optique. Nos résultats suggèrent une possible atrophie maculaire infraclinique chez les sujets NMOSD. Les corrélations entre OCT et handicap visuel étaient bonnes et nombreuses. Dans la NMOSD, les corrélations entre OCT et handicap clinique étaient moins nombreuses et liée à la présence d'un handicap visuel.(6) Nous avons mis en évidence une bonne association (p<0.0001) entre la longueur de l'hypersignal DIR du nerf optique, l'épaisseur de la pRNFL, le volume des couches maculaires internes et le handicap visuel. Près de 40% des yeux indemnes de NO présentaient un hypersignal du nerf optique.CONCLUSIONS.Nous avons développé une séquence DTI analysant la moelle épinière cervicale, applicable en routine et de façon prospective. Les corrélations entre la FA ou la MD et le handicap restent toutefois modérées [...] / BACKGROUND.Inflammatory diseases affecting the central nervous system (CNS) are mainly represented by multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD). Both diseases may be associated with slight to severe clinical disability. There is a need for developing imaging biomarkers which could be used for diagnostic purposes and as potential therapeutic biomarkers. Optical coherence tomography (OCT) and magnetic resonance imaging (MRI) are robust and reproducible tools enabling us to measure axonal loss in vivo.OBJECTIVES.To develop OCT and MRI biomarkers for the diagnosis, prognosis and follow-up of inflammatory diseases affecting CNS.METHODS.Our MRI is a 3 teslas MRI (Achieva, Philips, Best the Netherlands) devoted to research at CHRU de Lille. The OCT tool is a 4th generation spectral-domain OCT (Heidelberg Spectralis, Germany).(1) We firstly developped a coronal diffusion tensor imaging (DTI) sequence for cervical spinal cord and (2) applied it to a large MS cohort in order to evaluate potential DTI/clinical disability correlations. (3) We interested in 3D-Double Inversion Recovery (DIR) sequence for the detection of T2 optic nerve hypersignal and compare its diagnosis accuracy with coronal 2D STIR-FLAIR sequence.Considering OCT, (4) we participated to a multicenter study for validating OCT quality criteria by measuring inter rater agreement. (5) We made a comparative OCT study in MS, NMOSD and healthy controls (HC), in order to describe potential OCT parameters differentiating both diseases. OCT parameters will be peripapillary retinal nerve fiber layers thickness (pRNFL; global and values per quadrants) and macular layers thickness evaluated by HEYEX segmentation software. (6) We investigated the length of optic nerve DIR hypersignal as a potential biomarker for retinal axonal loss measured by OCT.RESULTS.(1) The DTI parameters (fractional anisotropy [FA], mean diffusivity [MD], radial diffusivity [rD]) were significantly different between HC and MS patients. FA was reduced. MD and rD were increased.(2) In MS, FA within cervical spinal cord (C2-C6) was moderately correlated with physical disability measured by EDSS, pyramidal, sensory and bowel/urinary functional scores.(3) 3D-DIR sequence was more accurate than 2D STIR FLAIR for the detection of optic nerve hypersignal (Se 95%, Sp 94%) and showed the higher inter-rater agreement (kappa = 0.96).(4) The inter-rater agreement for OSCAR-IB quality criteria for retinal OCT was substantial (kappa = 0.7).(5) We found comparable post ON atrophy between MS and NMOSD and significant macular and temporal pRNFL atrophy in MS non ON eyes. We suggested possible subclinical macular atrophy in NMOSD. Correlations were good and numerous between OCT parameters and visual disability in both diseases. In NMOSD, correlations between OCT and clinical disability were fewer and more related to visual disability.(6) We found good associations (p<0.0001) between optic nerve DIR hypersignal length, pRNFL thicknesses, inner retinal layers volumes and visual disability. A subclinical radiological involvement of non ON eyes was found in 38.5%.CONCLUSION.We developed a DTI sequence for cervical spinal cord analysis which seems applicable in routine and in a prospective follow-up. However, correlations between FA or MD and clinical disability remain moderate.OCT may help to differentiate NMOSD and MS by focusing on the non ON eyes (temporal pRNFL atrophy more severe in MS). Moreover we discuss the possibility of subclinical retinal degenerative process in NMOSD.We showed the 3D-DIR interest in optic nerve inflammatory lesion detection. 3D-DIR sequence which has largely been considered as a marker of demyelination, may be more pathologically specific (i.e retinal axonal loss) by focusing on a specific part of the CNS (i.e optic nerve). Optic nerve DIR hypersignal may be a new biomarker of retinal axonal loss.

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