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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.
61

Dopaminergic Denervation Enhances Susceptibility to Hydroxyl Radicals in Rat Neostriatum

Kostrzewa, R. M., Kostrzewa, J. P., Brus, R. 14 October 2000 (has links)
To determine if greater amounts of hydroxyl radical (·OH) are formed by dopamine (DA) denervation and treatment with L-dihydroxyphenylalanine (L-DOPA), the neostriatum was DA denervated (99% reduction in DA content) by 6-hydroxydopamine treatment (134μg icv, desipramine pretreatment) of neonatal rats. At 10 weeks the peripherally restricted dopa decarboxylase inhibitor carbidopa (12.5mg/kg i.p.) was administered 30min before vehicle, L-DOPA (60mg/kg i.p.), or the known generator of reactive oxygen species, 6-hydroxydopa (6-OHDOPA) (60mg/ kg i.p.); and this was followed 30min later (and 15 min before termination) by the spin trap, salicylic acid (8 μmoles icv). By means of a high performance liquid chromatographic method with electrochemical detection, we found a 4-fold increase in the non-enzymatically formed spin trap product, 2,3-dihydroxybenzoic acid (2,3-DHBA), with neither L-DOPA nor 6-OHDOPA having an effect on 2,3-DHBA content of the neostriatum. Basal content of 2,5-DHBA, the enzymatically formed spin trap product, was 4-fold higher vs. 2,3-DHBA in the neostriatum of untreated rats, while L-DOPA and 6-OHDOPA each reduced formation of 2,5-DHBA. We conclude that DA innervation normally suppresses ·OH formation, and that the antiparkinsonian drug L-DOPA has no effect (2,3-DHBA) or slightly reduces (2,5-DHBA) ·OH formation in the neostriatum, probably by virtue of its bathing the system of newly formed ·OH.
62

Levodopa Drug Induced Alteration of Thiol Homeostasis in Model Neurons Activates Apoptosis Signaling Kinase 1: Implications for the Treatment of Parkinson's Disease

Sabens, Elizabeth Ann January 2010 (has links)
No description available.
63

Characterization of the Zona Incerta

Green, Heather Joyce 01 January 2005 (has links)
Parkinson's Disease affects more than 1 million people in the United States with 60,000 new cases being diagnosed each year. Currently, there is no cure for Parkinson's Disease, but there are several treatment options available. Currently the most popular surgical option is Deep Brain Stimulation. Microelectrode recording helps identify nuclei as the microelectrode passes through them. While the firing frequencies of the target nuclei are well defined, other nuclei are not. This study will attempt to characterize the Zona Incerta, which is the structure directly above the Subthalamic Nucleus, a target nucleus. Characterization of the firing frequency of the Zona Incerta will help aid Deep Brain Stimulation procedures. Looking at the Interspike Intervals for 25 files showed that the average firing frequency is 11.6Hz. A file recorded in the STN was used for comparison and to validate the methods used. This yielded an average firing frequency of 37.5Hz.
64

Optimizing levodopa dosing routines for Parkinson’s disease

Thomas, Ilias January 2017 (has links)
This thesis in the field of microdata analysis aims to introduce dose optimizing algorithms for the pharmacological management of Parkinson’s disease (PD). PD is a neurodegenerative disease that mostly affects the motor functions of the patients and it is characterized as a movement disorder. The core symptoms of PD are: bradykinesia, postural instability, rigidity, and tremor. There is no cure for PD and the use of levodopa to manage the core symptoms is considered the gold standard. However, long term use of levodopa causes reduced medication efficacy, and side effects, such as dyskinesia, which can also be attributed to overmedication. When that happens precise individualized dosing schedules are required. The goal of this thesis is to examine if algorithmic methods can be used to find dosing schedules that treat PD symptoms and minimize manifestation of side effects. Data from three different sources were used for that purpose: data from a clinical study in Uppsala University hospital in 2015, patient admission chart data from Uppsala University hospital during 2011-2015, and data from a clinical study in Gothenburg University during 2016-2017. The data were used to develop the methods and evaluate the performance of the proposed algorithms.The first algorithm that was developed was a sensor-based method that derives objective measurements (ratings) of PD motor states. The construction of the sensor index was based on subjective ratings of patients’ motor functions made by three movement disorder experts. This sensor-based method was used when deriving algorithmic dosing schedules. Afterwards, a method that uses medication information and ratings of the patients’ motor states to fit individual patient models was developed. This method uses mathematical optimization to individualize specific parameters of dose-effects models for levodopa intake, through minimizing the distance between motor state ratings and dose-effect curves. Finally, two different dose optimization algorithms were developed and evaluated, that had as input the individual patient models. The first algorithm was specific to continuous infusion of levodopa treatment, where the patient’s state was set to a specific target value and the algorithm made dosing adjustments to keep that patients motor functions on that state. The second algorithm concerned oral administration of microtables of levodopa. The ambition with this algorithm was that the suggested doses would find the right balance between treating the core symptoms of PD and, at the same time, minimizing the side effects of long term levodopa use, mainly dyskinesia. Motor state ratings for this study were obtained through the sensor index. Both algorithms followed a principle of deriving a morning dose and a maintenance dose for the patients, with maintenance dose being an infusion rate for the first algorithm, and oral administration doses at specific time points for the second algorithm.The results showed that the sensor-based index had good test-retest reliability, sensitivity to levodopa treatment, and ability to make predictions in unseen parts of the dataset. The dosing algorithm for continuous infusion of levodopa had a good ability to suggest an optimal infusion rating for the patients, but consistently suggested lower morning dose than what the treating personnel prescribed. The dosing algorithm for oral administration of levodopa showed great agreement with the treating personnel’s prescriptions, both in terms of morning and maintenance dose. Moreover, when evaluating the oral medication algorithm, it was clear that the sensor index ratings could be used for building patient specific models.
65

Avaliação quantitativa dos efeitos da levodopa e da estimulação do núcleo subtalâmico sobre o equilíbrio em pacientes com doença de Parkinson / Quantitative evaluation of the effects of levodopa and bilateral subthalamic stimulation on postural control in patients with Parkinson´s disease

Rodrigues, Rachael Brant Machado 23 March 2016 (has links)
INTRODUÇÃO: Os efeitos da levodopa (LD) e da estimulação cerebral profunda (ECP) de núcleo subtalâmico (STN) sobre o equilíbrio e sintomas axiais são até o momento controversos. OBJETIVOS: Avaliar quantitativamente os efeitos da ECP de STN e da LD sobre o equilíbrio estático em pacientes com DP operados, em comparação com a LD em pacientes não operados. MÉTODOS: Trinta e um pacientes submetidos a ECP de STN entre 3 meses e 1 ano e meio antes da avaliação e 26 controles portadores de DP não operados, estágios Hoehn e Yahr 2 a 4 foram avaliados usando UPDRS para avaliação clínica e plataforma de força para avaliar oscilações posturais. O primeiro grupo foi avaliado com ECP e sem medicação, com ECP e com medicação e sem ECP e sem medicação. O segundo grupo foi avaliado com e sem medicação. Cada paciente foi avaliado com os olhos abertos e fechados. O deslocamento do centro de pressão anteroposterior, laterolateral, a área, velocidade e deslocamento total linear foram medidos pela plataforma de força. Os dados paramétricos foram comparados usando o teste t de Student e os dados não-paramétricos foram comparados pelo teste de Kruskal-Wallis. A avaliação clínica consistiu na parte 3 da escala UPDRS e na escala Hoehn e Yahr. Nível de significância estatística considerada foi p=0,05. RESULTADOS: Os pacientes não operados oscilaram mais quando sob efeito da levodopa do que sem medicação. No grupo operado, a maior oscilação é no grupo com ECP desligada e sem medicação. Tende a reduzir sob efeito da ECP apresenta redução significativa sob efeito simultâneo de ECP e levodopa. CONCLUSÃO: A associação da ECP de NST com medicação tem impacto positivo sobre o controle postural. O efeito da ECP de NST reverte o efeito negativo da levodopa sobre as oscilações observadas em pacientes não operados / INTRODUCTION: The effects of bilateral subthalamic (STN) DBS and medication on balance and on axial symptoms in PD have been so far inconsistent. OBJECTIVE: To assess quantitatively the effects of DBS on static balance in PD. METHODS: Thirty-one patients submitted to STN DBS over 3 months before and 26 non-operated controls with PD on Hoehn & Yahr stage \"on\" 2 to 4 were evaluated using UPDRS and a force plate to measure sway. The first group was evaluated on-DBS/off-medication, on-DBS/on-medication and off-DBS/off-medication. The second group was evaluated on and off medication. Each group was assessed with eyes open and then closed. Antero-posterior, laterolateral postural displacements of the center of pressure (COP), as well as 95% sway area, path length and speed of oscillation were analyzed and compared using t-Student test for parametrical data and Kruskal-Wallis test for non-parametrical data. Level of significance was set to p < 0.05. Clinical assessment consisted of UPDRS part 3 and Hoehn & Yahr scores for each of the conditions. RESULTS: Control patients tended to oscillate more in the on medication condition than off medication. DBS patients tended to oscillate more in the off-DBS/off medication condition, with a tendency to decrease the sway when on DBS/off medication with additional decrease when on DBS/on medication. CONCLUSION: Association of bilateral STN DBS and medication positively influences postural control in PD and surgery reverses the tendency of medication to increase body sway in non-operated patients
66

Avaliação quantitativa dos efeitos da levodopa e da estimulação do núcleo subtalâmico sobre o equilíbrio em pacientes com doença de Parkinson / Quantitative evaluation of the effects of levodopa and bilateral subthalamic stimulation on postural control in patients with Parkinson´s disease

Rachael Brant Machado Rodrigues 23 March 2016 (has links)
INTRODUÇÃO: Os efeitos da levodopa (LD) e da estimulação cerebral profunda (ECP) de núcleo subtalâmico (STN) sobre o equilíbrio e sintomas axiais são até o momento controversos. OBJETIVOS: Avaliar quantitativamente os efeitos da ECP de STN e da LD sobre o equilíbrio estático em pacientes com DP operados, em comparação com a LD em pacientes não operados. MÉTODOS: Trinta e um pacientes submetidos a ECP de STN entre 3 meses e 1 ano e meio antes da avaliação e 26 controles portadores de DP não operados, estágios Hoehn e Yahr 2 a 4 foram avaliados usando UPDRS para avaliação clínica e plataforma de força para avaliar oscilações posturais. O primeiro grupo foi avaliado com ECP e sem medicação, com ECP e com medicação e sem ECP e sem medicação. O segundo grupo foi avaliado com e sem medicação. Cada paciente foi avaliado com os olhos abertos e fechados. O deslocamento do centro de pressão anteroposterior, laterolateral, a área, velocidade e deslocamento total linear foram medidos pela plataforma de força. Os dados paramétricos foram comparados usando o teste t de Student e os dados não-paramétricos foram comparados pelo teste de Kruskal-Wallis. A avaliação clínica consistiu na parte 3 da escala UPDRS e na escala Hoehn e Yahr. Nível de significância estatística considerada foi p=0,05. RESULTADOS: Os pacientes não operados oscilaram mais quando sob efeito da levodopa do que sem medicação. No grupo operado, a maior oscilação é no grupo com ECP desligada e sem medicação. Tende a reduzir sob efeito da ECP apresenta redução significativa sob efeito simultâneo de ECP e levodopa. CONCLUSÃO: A associação da ECP de NST com medicação tem impacto positivo sobre o controle postural. O efeito da ECP de NST reverte o efeito negativo da levodopa sobre as oscilações observadas em pacientes não operados / INTRODUCTION: The effects of bilateral subthalamic (STN) DBS and medication on balance and on axial symptoms in PD have been so far inconsistent. OBJECTIVE: To assess quantitatively the effects of DBS on static balance in PD. METHODS: Thirty-one patients submitted to STN DBS over 3 months before and 26 non-operated controls with PD on Hoehn & Yahr stage \"on\" 2 to 4 were evaluated using UPDRS and a force plate to measure sway. The first group was evaluated on-DBS/off-medication, on-DBS/on-medication and off-DBS/off-medication. The second group was evaluated on and off medication. Each group was assessed with eyes open and then closed. Antero-posterior, laterolateral postural displacements of the center of pressure (COP), as well as 95% sway area, path length and speed of oscillation were analyzed and compared using t-Student test for parametrical data and Kruskal-Wallis test for non-parametrical data. Level of significance was set to p < 0.05. Clinical assessment consisted of UPDRS part 3 and Hoehn & Yahr scores for each of the conditions. RESULTS: Control patients tended to oscillate more in the on medication condition than off medication. DBS patients tended to oscillate more in the off-DBS/off medication condition, with a tendency to decrease the sway when on DBS/off medication with additional decrease when on DBS/on medication. CONCLUSION: Association of bilateral STN DBS and medication positively influences postural control in PD and surgery reverses the tendency of medication to increase body sway in non-operated patients
67

Synthesis and evaluation of sesamol derivatives as inhibitors of monoamine oxidase / Idalet Engelbrecht

Engelbrecht, Idalet January 2014 (has links)
Parkinson’s disease is an age-related neurodegenerative disorder. The major symptoms of Parkinson’s disease are closely linked to the pathology of the disease. The main pathology of Parkinson’s disease consists of the degeneration of neurons of the substantia nigra pars compacta (SNpc), which leads to reduced amounts of dopamine in the brain. One of the treatment strategies in Parkinson’s disease is to conserve dopamine by inhibiting the enzymes responsible for its catabolism. The monoamine oxidase (MAO) B isoform catalyses the oxidation of dopamine in the central nervous system and is therefore an important target for Parkinson’s disease treatment. Inhibition of MAO-B provides symptomatic relief for Parkinson’s disease patients by increasing endogenous dopamine levels as well as enhancing the levels of dopamine after administration of levodopa (L-dopa), the metabolic precursor of dopamine. Recent studies have shown that phthalide can be used as a scaffold for the design of reversible MAO inhibitors. Although phthalide is a weak MAO-B inhibitor, substitution on the C5 position of phthalide yields highly potent reversible MAO-B inhibitors. In the present study, sesamol and benzodioxane were used as scaffolds for the design of MAO inhibitors. The structures of sesamol and benzodioxane closely resemble that of phthalide, which suggests that these moieties may be useful for the design of MAO inhibitors. This study may be viewed as an exploratory study to discover new scaffolds for MAO inhibition. Since substitution at C5 of phthalide with a benzyloxy side chain yielded particularly potent MAO inhibitors, the sesamol and benzodioxane derivatives possessed the benzyloxy substituent in the analogous positions to C5 of phthalide. These were the C5 and C6 positions of sesamol and benzodioxane, respectively. The sesamol and benzodioxane derivatives were synthesised by reacting sesamol and 6- hydroxy-1,4-benzodioxane, respectively, with an appropriate alkyl bromide in the presence of potassium carbonate (K2CO3) in N,N-dimethylformamide (DMF). 6-Hydroxy-1,4- benzodioxane, in turn, was synthesised from 1,4-benzodioxan-6-carboxaldehyde. The structures of the compounds were verified with nuclear magnetic resonance (NMR) and mass spectrometry (MS) analyses, while the purities were estimated by high-pressure liquid chromatography (HPLC). Sixteen sesamol and benzodioxane derivatives were synthesised. To determine the inhibition potencies of the synthesised compounds the recombinant human MAO-A and MAO-B enzymes were used. The inhibition potencies were expressed as the corresponding IC50 values. The results showed that the sesamol and benzodioxane derivatives are highly potent and selective inhibitors of MAO-B and to a lesser extent MAOA. The most potent MAO-B inhibitor was 6-(3-bromobenzyloxy)-1,4-benzodioxane with an IC50 value of 0.045 μM. All compounds examined displayed selectivity for the MAO-B isoform over MAO-A. Generally the benzodioxane derivatives were found to be more potent inhibitors of human MAO-A and MAO-B than the sesamol derivatives. The reversibility and mode of MAO-B inhibition of a representative derivative, 6-(3- bromobenzyloxy)-1,4-benzodioxane, was examined by measuring the degree to which the enzyme activity recovers after dialysis of enzyme-inhibitor complexes, while Lineweaver- Burk plots were constructed to determine whether the mode of inhibition is competitive. Since MAO-B activity is completely recovered after dialysis of enzyme-inhibitor mixtures, it was concluded that 6-(3-bromobenzyloxy)-1,4-benzodioxane binds reversibly to the MAO-B enzyme. The Lineweaver-Burk plots constructed were linear and intersected on the y-axis. Therefore it may be concluded that 6-(3-bromobenzyloxy)-1,4-benzodioxane is a competitive MAO-B inhibitor. To conclude, the C6-substituted benzodioxane derivatives are potent, selective, reversible and competitive inhibitors of human MAO-B. These compounds are therefore promising leads for the future development of therapy for Parkinson’s disease. / MSc (Pharmaceutical Chemistry), North-West University, Potchefstroom Campus, 2015
68

Synthesis and evaluation of sesamol derivatives as inhibitors of monoamine oxidase / Idalet Engelbrecht

Engelbrecht, Idalet January 2014 (has links)
Parkinson’s disease is an age-related neurodegenerative disorder. The major symptoms of Parkinson’s disease are closely linked to the pathology of the disease. The main pathology of Parkinson’s disease consists of the degeneration of neurons of the substantia nigra pars compacta (SNpc), which leads to reduced amounts of dopamine in the brain. One of the treatment strategies in Parkinson’s disease is to conserve dopamine by inhibiting the enzymes responsible for its catabolism. The monoamine oxidase (MAO) B isoform catalyses the oxidation of dopamine in the central nervous system and is therefore an important target for Parkinson’s disease treatment. Inhibition of MAO-B provides symptomatic relief for Parkinson’s disease patients by increasing endogenous dopamine levels as well as enhancing the levels of dopamine after administration of levodopa (L-dopa), the metabolic precursor of dopamine. Recent studies have shown that phthalide can be used as a scaffold for the design of reversible MAO inhibitors. Although phthalide is a weak MAO-B inhibitor, substitution on the C5 position of phthalide yields highly potent reversible MAO-B inhibitors. In the present study, sesamol and benzodioxane were used as scaffolds for the design of MAO inhibitors. The structures of sesamol and benzodioxane closely resemble that of phthalide, which suggests that these moieties may be useful for the design of MAO inhibitors. This study may be viewed as an exploratory study to discover new scaffolds for MAO inhibition. Since substitution at C5 of phthalide with a benzyloxy side chain yielded particularly potent MAO inhibitors, the sesamol and benzodioxane derivatives possessed the benzyloxy substituent in the analogous positions to C5 of phthalide. These were the C5 and C6 positions of sesamol and benzodioxane, respectively. The sesamol and benzodioxane derivatives were synthesised by reacting sesamol and 6- hydroxy-1,4-benzodioxane, respectively, with an appropriate alkyl bromide in the presence of potassium carbonate (K2CO3) in N,N-dimethylformamide (DMF). 6-Hydroxy-1,4- benzodioxane, in turn, was synthesised from 1,4-benzodioxan-6-carboxaldehyde. The structures of the compounds were verified with nuclear magnetic resonance (NMR) and mass spectrometry (MS) analyses, while the purities were estimated by high-pressure liquid chromatography (HPLC). Sixteen sesamol and benzodioxane derivatives were synthesised. To determine the inhibition potencies of the synthesised compounds the recombinant human MAO-A and MAO-B enzymes were used. The inhibition potencies were expressed as the corresponding IC50 values. The results showed that the sesamol and benzodioxane derivatives are highly potent and selective inhibitors of MAO-B and to a lesser extent MAOA. The most potent MAO-B inhibitor was 6-(3-bromobenzyloxy)-1,4-benzodioxane with an IC50 value of 0.045 μM. All compounds examined displayed selectivity for the MAO-B isoform over MAO-A. Generally the benzodioxane derivatives were found to be more potent inhibitors of human MAO-A and MAO-B than the sesamol derivatives. The reversibility and mode of MAO-B inhibition of a representative derivative, 6-(3- bromobenzyloxy)-1,4-benzodioxane, was examined by measuring the degree to which the enzyme activity recovers after dialysis of enzyme-inhibitor complexes, while Lineweaver- Burk plots were constructed to determine whether the mode of inhibition is competitive. Since MAO-B activity is completely recovered after dialysis of enzyme-inhibitor mixtures, it was concluded that 6-(3-bromobenzyloxy)-1,4-benzodioxane binds reversibly to the MAO-B enzyme. The Lineweaver-Burk plots constructed were linear and intersected on the y-axis. Therefore it may be concluded that 6-(3-bromobenzyloxy)-1,4-benzodioxane is a competitive MAO-B inhibitor. To conclude, the C6-substituted benzodioxane derivatives are potent, selective, reversible and competitive inhibitors of human MAO-B. These compounds are therefore promising leads for the future development of therapy for Parkinson’s disease. / MSc (Pharmaceutical Chemistry), North-West University, Potchefstroom Campus, 2015
69

Effect of levodopa on cortico-striatal and cortico-cerebellar circuits in Parkinson's disease

Martinu, Kristina 09 1900 (has links)
La maladie de Parkinson (MP) est la deuxième maladie neurodégénérative la plus commune. Les symptômes principalement observés chez les patients atteints de la MP sont la rigidité, les tremblements, la bradykinésie et une instabilité posturale. Leur sévérité est souvent asymétrique. La cause principale de ces symptômes moteurs est la dégénérescence du circuit dopaminergique nigro-striatal qui mène à un débalancement d’activité du circuit cortico-striatal. Ce débalancement de circuits est le point essentiel de cette thèse. Dans les protocoles de recherche décrits ici, des patients atteints de la MP (avant et après une dose de levodopa) et des participants contrôles sains ont effectué des mouvements auto-initiés ou en réponse à des stimulis externes pendant que l’on mesurait leur activité cérébrale en imagerie par résonance magnétique fonctionnelle (IRMf). Dans cette thèse, nous abordons et mettons en évidence quatre (4) points principaux. En première partie (chapitre 2), nous présentons un recensement de la littérature sur les cicruits cortico-striataux et cortico-cérébelleux dans la MP. En utilisant des méthodes de neuroimagerie, des changements d’activité cérébrale et cérébelleuse ont été observés chez les patients atteints de la MP comparés aux participants sains. Même si les augmentations d’activité du cervelet ont souvent été attribuées à des mécanismes compensatoires, nos résultats suggèrent qu’elles sont plus probablement liées aux changements pathophysiologiques de la MP et à la perturbation du circuit cortico-cérébelleux. En général, nous suggérons (1) que le circuit cortico-cérébelleux est perturbé chez les patients atteints de la MP, et que les changements d’activité du cervelet sont liés à la pathophysiologie de la MP plutôt qu’à des mécanismes compensatoires. En deuxième partie (chapitre 3), nous discutons des effets de la levodopa sur les hausses et baisses d’activité observés chez les patients atteints de la MP, ainsi que sur l’activité du putamen pendant les mouvements d’origine interne et externe. De nombreuses études en neuroimagerie ont montré une baisse d’activité (hypo-activité) préfrontale liée à la déplétion de dopamine. En revanche, l’utilisation de tâches cognitives a montré des augmentations d’activité (hyper-activité) corticale chez les patients atteints de la MP comparés aux participants sains. Nous avons suggéré précédemment que ces hypo- et hyper-activités des régions préfrontales dépendent de l’implication du striatum. Dans cette thèse nous suggérons de plus (2) que la levodopa ne rétablit pas ces hyper-activations, mais plutôt qu’elles sont liées à la perturbation du circuit méso-cortical, et aussi possiblement associées à l’administration de médication dopaminergique à long terme. Nous montrons aussi (3) que la levodopa a un effet non-spécifique à la tâche sur l’activité du circuit cortico-striatal moteur, et qu’elle n’a pas d’effet sur l’activité du circuit cortico-striatal cognitif. Nous montrons enfin (chapitre 4) que la levodopa a un effet asymétrique sur les mouvements de la main droite et gauche. À peu près 50% des patients atteints de la MP démontrent une asymétrie des symptômes moteurs, et ceci persiste à travers la durée de la maladie. Nos résultats suggèrent (4) que la levodopa pourrait avoir un plus grand effet sur les patrons d’activations des mouvements de la main la plus affectée. / Parkinson’s disease (PD) is the second most common neurodegenerative disease, mainly manifested by tremor, rigidity, bradykinesia and postural instability, and often an asymmetry of symptom severity of the left and right sides of the body. The depletion of dopamine of the nigrostriatal pathway is the primary cause of the motor symptoms observed in patients with PD, leading to an imbalance in basal-ganglia prefrontal circuits. In the protocols described here, patients with PD before and after levodopa administration and healthy participants performed self-initiated (SI) and externally triggered (ET) movements with the left and right hand during functional magnetic resonance imaging (fMRI). In the chapters of this thesis, we argue and provide evidence for four main points. The first portion (chapter 2) provides a literature review on cortico-striatal and cortico-cerebellar circuit disruption in PD. Using neuroimaging techniques, changes in cerebral and cerebellar activity have been observed in patients with PD compared with healthy participants. Although increases in activity in the cerebellum have often been interpreted as compensatory mechanisms, we provide evidence that they are more likely to be related to pathophysiological changes of the disease, and the disruption of the cortico- cerebellar circuit. In general, we argue (1) is that activity in the cerebellum is linked to the pathophysiology of PD. In the second section (chapter 3) we discuss the effect of levodopa on the patterns of cortical hypo- and hyper-activity in PD, as well as the activity of the putamen in SI and ET movements. Many studies have shown cortical hypo-activity in relation to nigrostriatal dopamine depletion. In contrast, some cognitive studies have also identified increases in cortical activity in patients with PD as compared with healthy control participants. We have previously suggested that cortical hypo- and hyper-activations depend on striatal recruitment. In this thesis, we further show that hyper-activations in the prefrontal cortex are not reestablished with levodopa administration. We suggest (2) that they are rather associated with mesocortical dopamine circuit dysfunction, and perhaps linked with long- term dopaminergic medication administration. Furthermore, we show (3) that levodopa has a non-task specific effect on the motor cortico-striatal loop, but does not affect the cognitive cortico-striatal circuit. Finally (chapter 4), we show that the effect of levodopa on movements of the left and right hands is not symmetrical. Previous studies have shown that in about 50% of patients, one side of the body is more severely affected, and this asymmetry persists throughout the duration of the disease. Our results suggest (4) that levodopa may have stronger effects on the cerebral hemodynamic patterns related to the movements of the more affected hand than on those of the less affected hand.
70

Decision Support for Treatment of Patients with Advanced Parkinson’s Disease / Beslutsstöd för behandling av patienter med avancerad Parkinsons sjukdom

Westin, Jerker January 2010 (has links)
The overall aim of this thesis was to develop, deploy and evaluate new IT-based methods for supporting treatment and assessment of treatment of advanced Parkinson’s disease. In this condition a number of different motor and non-motor symptoms occur in episodes of varying frequency, duration and severity. In order to determine outcome of treatment changes, repeated assessments are necessary. Hospitalization for observation is expensive and may not be representative for the situation at home. Paper home diaries have questionable reliability and storage and retrieval of results are problematic. Approaches for monitoring using wearable sensors are unable to address important non-motor symptoms. A test battery system consisting of both self-assessments of symptoms and motor function tests was constructed for a touch screen mobile phone. Tests are performed on several occasions per day during test periods of one week. Data is transmitted over the mobile net to a central server where summaries in different symptom dimensions and an overall test score per patient and test period are calculated. There is a web application that graphically presents the results to treating clinical staff. As part of this work, a novel method for assessment of spiral drawing impairment useful during event-driven sampling was developed. To date, the system has been used by over 100 patients in 10 clinics in Sweden and Italy. Evidence is growing that the test battery is useful, reliable and valid for assessment of symptoms during advanced Parkinson’s disease. Infusion of a levodopa/carbidopa gel into the small intestine has been shown to reduce variation in plasma drug levels and improve clinical response in this patient category. A pharmacokinetic-pharmacodynamic model of this intestinal gel infusion was constructed. Possibly this model can assist the process of individualization of dosage for this treatment through in numero simulations. Results from an exploratory data analysis indicate that severity measures during oral levodopa treatment may be factors to consider when deciding candidates for infusion treatment.

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