<p>Studies of protein and peptide expression are vital in order to understand complex biological systems. As demonstrated in this thesis, on-line packed capillary liquid chromatography-Fourier transform ion cyclotron resonance mass spectrometry (LC-FTICR MS) is a useful analytical tool for such studies.</p><p>A proteomics method, based on global tryptic digestion and subsequent separation and detection of the peptides by LC-FTICR MS, was developed for qualitative analysis of body fluids. Initial experiments on cerebrospinal fluid (CSF) provided results that were comparable or superior to those achieved by more time- and sample-consuming techniques. The method was also successfully applied on plasma and amniotic fluid. One of the major challenges in proteomics is the broad dynamic range of proteins in biological matrices. The advantages of removing high-abundant components from CSF and plasma prior to MS were demonstrated.</p><p>In order to search for potential biomarkers, mass chromatograms of CSF from patients suffering from amyotrophic lateral sclerosis (ALS) and controls were compared using an in-house constructed pattern recognition program. ALS-specific patterns were observed, and four out of five unknown samples were correctly assigned. Alternative strategies to quantitatively compare two pools of samples rely on differential chemical labeling. The performance of one such method, quantification-using-enhanced-signal-tags, was investigated in complex sample analysis. The experimental intensity ratios were proven to be consistent with the prepared concentration ratios of abundant proteins in CSF.</p><p>Finally, the thesis reports on the first experiments where electron capture dissociation (ECD) was successfully incorporated in on-line LC-MS experiments. ECD and nozzle-skimmer fragmentation were applied to a sample of endocrine peptides extracted from mouse pancreatic islets. The two fragmentation methods provided complementary information. However, the method needs further optimization before it can be applied in the analysis of more complex samples, such as body fluids.</p>

Amyotrophic lateral sclerosis is a fatal, progressive neurodegenerative disease with unknown ethiology. The aim of this study was to increase understanding of the pathophysiological mechanisms of dying motor neurons and wasting muscle tissue in this particular disorder. Quantitative receptor autoradiographic methodology was applied on cervical spinal cord sections from patients with ALS to evaluate the specific binding of the acetylcholine transporter 3H-vesamicol in motor neurons. Despite a significant reduction of the number of ventral motor neurons in ALS, the 3H-vesamicol binding was not reduced in ALS compared to control cases, which suggests an increased metabolic activity in remaining motor neurons. Motor neurons dying in ALS might go through apoptosis (programmed cell death), so immunohistochemical and TUNEL techniques were applied on thoracic spinal cord from ALS patients to evaluate the possibility of an apoptotic process. The increased Bax expression indicates an apoptotic process and further, motor neurons were TUNEL-positive, indicating DNA degradation caused by programmed cell death. Muscle biopsies were obtained from ALS patients, and mRNA levels for the neurotrophic factors GDNF and BDNF were measured and compared to control subjects. GDNF levels were increased in muscle tissue in ALS whereas BDNF levels were unaltered. Levels of GDNF and BDNF were also measured in cerebrospinal fluid from ALS patients and controls using ELISA methodology. Levels of BDNF were unaltered in ALS cornpared to controls. GDNF however was not detectable in controls whereas 12 out of 15 ALS patients had measurab1e levels of GDNW. A marked upregulation of endogenous GDNF and GDNF mRNA in ALS CSF and muscle respectively is of special interest in relation to clinical trials where GDNF is administered to this group of patients.

New biomarkers are needed to improve knowledge about pathophysiology, in order to provide earlier correct diagnosis and to follow disease progression of the neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and Parkinson's disease (PD). The aim of this thesis was to find new biomarkers for these diseases. First, increased serum levels and unchanged levels in postmortal spinal cord of vascular endothelial growth factor (VEGF) were demonstrated. VEGF was not detected in cerebrospinal fluid (CSF) in ALS. Second, increased levels of fibroblast growth factor 2 were found in the CSF and serum of ALS patients. Both studies used enzyme-linked immunoassays. Third, a proteomics method for CSF analysis was explored, based on tryptic digestion and subsequent separation and detection of the peptides by on-line liquid chromatography-Fourier transform ion cyclotron resonance mass spectrometry. ALS-specific patterns were observed. Four out of five samples were correctly assigned, but no single protein biomarker could be identified. Fourth, [11C](L)-deprenyl-D2 (DED) positron emission tomography (PET) demonstrated increased retention in the pons and white matter in ALS. DED binds to monoamino oxidase B, which in the brain is primarily located in astrocytes. Thus evidence was provided that astrocytosis may be detected in vivo in ALS. Fifth, normal [11C]-PIB binding in five nondemented patients with PD was reported, in contrast to previous findings of increased retention in Alzheimer's disease reflecting amyloid aggregation. Finally, the combined use of fluorodeoxyglucose and L-[β 11C]-DOPA PET for the differential diagnosis of parkinsonian syndromes was evaluated. PET provided support for the clinical diagnosis in 62 out of 75 patients, and served to exclude suspected diagnoses in another five patients.

Studies of protein and peptide expression are vital in order to understand complex biological systems. As demonstrated in this thesis, on-line packed capillary liquid chromatography-Fourier transform ion cyclotron resonance mass spectrometry (LC-FTICR MS) is a useful analytical tool for such studies. A proteomics method, based on global tryptic digestion and subsequent separation and detection of the peptides by LC-FTICR MS, was developed for qualitative analysis of body fluids. Initial experiments on cerebrospinal fluid (CSF) provided results that were comparable or superior to those achieved by more time- and sample-consuming techniques. The method was also successfully applied on plasma and amniotic fluid. One of the major challenges in proteomics is the broad dynamic range of proteins in biological matrices. The advantages of removing high-abundant components from CSF and plasma prior to MS were demonstrated. In order to search for potential biomarkers, mass chromatograms of CSF from patients suffering from amyotrophic lateral sclerosis (ALS) and controls were compared using an in-house constructed pattern recognition program. ALS-specific patterns were observed, and four out of five unknown samples were correctly assigned. Alternative strategies to quantitatively compare two pools of samples rely on differential chemical labeling. The performance of one such method, quantification-using-enhanced-signal-tags, was investigated in complex sample analysis. The experimental intensity ratios were proven to be consistent with the prepared concentration ratios of abundant proteins in CSF. Finally, the thesis reports on the first experiments where electron capture dissociation (ECD) was successfully incorporated in on-line LC-MS experiments. ECD and nozzle-skimmer fragmentation were applied to a sample of endocrine peptides extracted from mouse pancreatic islets. The two fragmentation methods provided complementary information. However, the method needs further optimization before it can be applied in the analysis of more complex samples, such as body fluids.

No description available.

In this thesis we develop several kinds of latent variable models in order to address three types of bio-statistical problem. The three problems are the treatment effect of carcinogens on tumour development, spatial interactions between plant species and motor unit number estimation (MUNE). The three types of data looked at are: highly heterogeneous longitudinal count data, quadrat counts of species on a rectangular lattice and lastly, electrophysiological data consisting of measurements of compound muscle action potential (CMAP) area and amplitude. Chapter 1 sets out the structure and the development of ideas presented in this thesis from the point of view of: model structure, model selection, and efficiency of estimation. Chapter 2 is an introduction to the relevant literature that has in influenced the development of this thesis. In Chapter 3 we use the EM algorithm for an application of an autoregressive hidden Markov model to describe longitudinal counts. The data is collected from experiments to test the effect of carcinogens on tumour growth in mice. Here we develop forward and backward recursions for calculating the likelihood and for estimation. Chapter 4 is the analysis of a similar kind of data using a more sophisticated model, incorporating random effects, but estimation this time is conducted from the Bayesian perspective. Bayesian model selection is also explored. In Chapter 5 we move to the two dimensional lattice and construct a model for describing the spatial interaction of tree types. We also compare the merits of directed and undirected graphical models for describing the hidden lattice. Chapter 6 is the application of a Bayesian hierarchical model (MUNE), where the latent variable this time is multivariate Gaussian and dependent on a covariate, the stimulus. Model selection is carried out using the Bayes Information Criterion (BIC). In Chapter 7 we approach the same problem by using the reversible jump methodology (Green, 1995) where this time we use a dual Gaussian-Binary representation of the latent data. We conclude in Chapter 8 with suggestions for the direction of new work. In this thesis, all of the estimation carried out on real data has only been performed once we have been satisfied that estimation is able to retrieve the parameters from simulated data. Keywords: Amyotrophic lateral sclerosis (ALS), carcinogens, hidden Markov models (HMM), latent variable models, longitudinal data analysis, motor unit disease (MND), partially ordered Markov models (POMMs), the pseudo auto- logistic model, reversible jump, spatial interactions.

Thesis (Ph. D.) -- University of Texas Southwestern Medical Center at Dallas, 2005. / Vita. Bibliography: 199-250.

Les maladies neurodégénératives (MND) comprennent principalement les maladies neuromusculaires, dont la sclérose latérale amyotrophique (SLA), les démences, dont la maladie d’Alzheimer, la maladie de Parkinson, la sclérose en plaques, la maladie de Huntington. Du fait de la multiplicité des facteurs à l’origine d’une perte pondérale, les MND sont à risque de dénutrition, ce qui peut altérer l’évolution de ces pathologies et la qualité de vie des patients. Le but de ce travail était d’étudier le statut nutritionnel et/ou l’effet de la prise en charge de patients atteints de SLA et de troubles cognitifs (démence vraie et/ou Mild Cognitive Impairment [MCI]) en France dans le cadre d’un réseau de santé, mais aussi en Afrique Centrale. Le réseau de santé Limousin Nutrition (LINUT) réalise des évaluations et interventions nutritionnelles au domicile de patients atteints de SLA et pour les résidents d’Etablissements d’Hébergement pour Personnes Agées Dépendantes (EHPAD). La première évaluation par le réseau des patients à domicile atteints de SLA retrouvait plus de troubles de la déglutition qu’en consultation spécialisée (60,0% vs 47,5%) ainsi que des troubles du goût (43,8%), non encore décrits lors de la SLA. Des améliorations de pratiques étaient proposées. Le réseau évaluait également des résidents en EHPAD, déments ou non déments, à la fois initialement et après un suivi d’environ 4 mois. La dénutrition touchait plus souvent les patients déments (56,1% vs 46,4% p=0,004), et les apports énergétiques de tous les résidents (26,4 ± 8,8 kcal/kg/j) étaient inférieurs aux recommandations. L’intervention du réseau permettait d’améliorer le statut nutritionnel des patients déments (+0,29 ± 0,07 point de MNA®/mois, p=0,003) ainsi que les apports énergétiques de tous les résidents à 4 mois. Les études « Epidémiologie de la Démence en Afrique Centrale » (EDAC) et « Epidemiology of Dementia in Central Africa » (EPIDEMCA) étaient menées en République Centrafricaine (RCA) et au Congo. Dans ces deux études, les personnes âgées démentes étaient plus souvent dénutries que les non démentes (EDAC : 34,7% vs 17,7%, p<0,0001 ; EPIDEMCA : 60,0% vs 31,3%, p<0,001). Dans l’étude EDAC, le fait de ne consommer qu’un repas par jour constituait un risque de dénutrition chez les déments (OR=7,23 [IC95% : 1,65-31,7, p=0,003]. De plus, les déments consommaient moins de fruits que les non déments (aucune consommation : 54,0% vs 36,7%, p=0,008). Dans l’étude EPIDEMCA, en RCA, une faible consommation d’oléagineux en zone rurale était associée à la présence d’une démence (OR=2,80 [IC95% : 1,02-7,70, p=0,046]), et une consommation d’alcool (quantités non étudiées) en population générale était négativement associée (OR=0,34 [IC95% : 0,14-0,83, p=0,018]). Aucune association n’était retrouvée au Congo. Des facteurs nutritionnels associés aux troubles cognitifs étaient identifiés : un Indice de Masse Corporelle <18,5kg/m2 , un périmètre brachial <24cm et une circonférence musculaire brachiale <5èmepercentile étaient associés en RCA à la démence (OR=2,66 [IC95% : 1,39-5,07, p=0,003] ; OR=1,97 [IC95% : 1,03-3,77, p=0,041] ; OR=2,94 [IC95% : 1,34-6,45, p=0,007], respectivement), et au Congo seule la circonférence musculaire brachiale <5èmepercentile était associée aux MCI (OR=3,61 [IC95% : 1,70-7,64, p=0,001]). Ces différents travaux permettent de disposer de nouvelles données concernant les patients atteints de SLA et de troubles cognitifs dans deux régions du globe. En France, une prise en charge par un réseau de santé est possible et semble améliorer le statut nutritionnel des personnes atteintes de MND. En Afrique Centrale, plusieurs facteurs associés aux troubles cognitifs ont été identifiés. Ces premiers résultats doivent être confirmés afin de proposer des moyens de prévention ciblés. / Neurodegenerative diseases (NDD) mainly concern neuromuscular diseases, including amyotrophic lateral sclerosis (ALS), dementia, including Alzheimer's disease, Parkinson's disease, multiple sclerosis, Huntington's disease. Due to the multiplicity of factors inducing a weight loss, the NDD are at risk of malnutrition, which can alter the evolution of these diseases and the quality of life of patients. The purpose of this work was to assess the nutritional status and / or the effect of treatment of patients with ALS and cognitive disorders (dementia and / or mild cognitive impairment [MCI]) in France with a health network, but also in Central Africa. The health network Limousin Nutrition (LINUT) realizes assessments and nutritional interventions in ALS patients at home and in residents of nursing homes (NH). The first evaluation by the network of ALS patients found more swallowing disorders than specialized consultation (60.0% vs. 47.5%) and taste disorders (43.8%), not further described in ALS. Improvements of practices were proposed. The network assessed also residents in NH, with or without dementia, initially and after a 4 months follow-up. Malnutrition affected more often demented patients (56.1% vs. 46.4% p=0.004), and energy intakes of all residents (26.4 ± 8.8 kcal/kg/d) were below the recommendations. The network intervention improved the nutritional status of patients with dementia (+0.29 ± 0.07 point of MNA®/month, p=0.003) and energy intake of all residents at 4 months. Two studies named

No description available.

Fundação de Amparo a Pesquisa do Estado de Alagoas / Esta pesquisa tem por objeto refletir sobre a expressão da vida psíquica do sujeito acometido pela Esclerose Lateral Amiotrófica (ELA), compreendida na vivência do seu corpo silenciado. Por esse termo designamos a peculiar condição do sujeito que, com o avanço da doença, tende a perder tanto a articulação da fala quanto dos movimentos, com um grave prejuízo em sua capacidade de se comunicar. Pretendemos compreender a expressão psíquica de tal sujeito a partir da interação dos cuidadores, familiares e profissionais de saúde no convívio com esse sujeito na fase avançada da doença. Utilizamos o método clínicoqualitativo de investigação (Turato, 2005), cuja pertinência à pesquisa humana em saúde está em buscar interpretar significados psicológicos e socioculturais trazidos por sujeitos afetados por doença, bem como dos cuidadores, familiares e profissionais. O número de participantes foi determinado pelo critério de saturação (Minayo, 1994), em que o pesquisador fecha o grupo quando determinado número de entrevistas já alcança o nível de informações esperadas. Coletamos depoimentos livres de oito participantes, sendo quatro profissionais de saúde com experiência no atendimento a casos de ELA: um neurologista, uma psicóloga, uma fonoaudióloga e uma fisioterapeuta, e quatro cuidadores e/ou familiares de pessoas acometidas pela ELA: uma filha de paciente, uma cuidadora contratada, uma esposa e uma viúva de paciente. Os participantes foram questionados a partir de dois aspectos de sua interação com o sujeito acometido pela ELA; em primeiro lugar, perguntamos de que modo, no convívio com o sujeito, conseguiam captar, interpretar e compreender suas vicissitudes. Em seguida, questionamos quais os recursos utilizados para o estabelecimento de uma comunicação intersubjetiva entre este profissional de saúde, familiar ou cuidador e o sujeito acometido pela ELA. Consideramos, finalmente, que a expressão-compreensão de vida psíquica do sujeito com ELA abrange uma gradação que vai desde elementos pragmáticos a posições relacionais por parte cuidadores, cuja complementaridade tem por efeito a apreensão dos conteúdos subjetivos dos pacientes