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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.
41

Chosen Children? : An empirical study and a philosophical analysis of moral aspects of pre-implantation genetic diagnosis and germ-line gene therapy

Zeiler, Kristin January 2005 (has links)
With pre-implantation genetic diagnosis (PGD), genetic testing and selective transfer of embryos is possible. In the future, germ-line gene therapy (GLGT) applied to embryos before implantation, in order to introduce missing genes or replace mutant ones, may be possible. The objective of this dissertation is to analyse moral aspects of these technologies, as described by eighteen British, Italian and Swedish gynaecologists and geneticists. The objective is systematised into three parts: research interviews and qualitative analysis, philosophical analysis, and elaboration of a framework that supports the combination of analytic methods. PGD was described as positive since it enabled some couples at risk for a genetic disease to have a child without the disease. PGD was described as in different senses ‘better’ than methods for prenatal diagnosis and selective termination of pregnancy. It was also described as positive since it provided couples at risk with one more option, even if it did not result in the birth of a healthy child. However, interviewees were concerned about the difficulty of defining and evaluating genetic disease. They were also concerned about patients’ choices, and about exaggerated use or misuse. Whereas PGD gave rise to ambivalence in terms of how to understand, describe and evaluate it, GLGT was often described as unrealistic or undesirable. The results of the qualitative analysis are used in a philosophical analysis of the concepts of choice, autonomous choice, ambivalence, trust and ambivalence in trust relations. A set of distinct characteristics of each concept are elaborated. The results of the philosophical analysis are used in the discussion of the results of the qualitative analysis. The study shows that the technologies imply both ‘new’ ways to perform ‘old’ medical practices and ‘new’ practices. Old moral questions are reformulated. New moral questions are added. Against the background of this, the concept of genetic identity is discussed. Key words: empirical ethics, pre-implantation genetic diagnosis, germ-line gene therapy, qualitative research, philosophical analysis, medical progress, genetic disease, choice, autonomous choice, ambivalence, trust, genetic identity.
42

Detecção de padrões espaciais na distribuição dos pacientes portadores de doença genética com deficiência física da Associação de Assistência à Criança Deficiente (AACD) de Pernambuco

CAMPOS, Ana Clara Paixão 02 February 2013 (has links)
Submitted by (ana.araujo@ufrpe.br) on 2016-05-20T12:26:11Z No. of bitstreams: 1 Ana Clara Paixao Campos.pdf: 1515481 bytes, checksum: 29c30eb35f6e7da1f6e63d0971def668 (MD5) / Made available in DSpace on 2016-05-20T12:26:11Z (GMT). No. of bitstreams: 1 Ana Clara Paixao Campos.pdf: 1515481 bytes, checksum: 29c30eb35f6e7da1f6e63d0971def668 (MD5) Previous issue date: 2013-02-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Knowing the spatial pattern of patients with genetic disease with physical disabilities in the treatment of Pernambuco AACD is of great importance because it makes it possible to guide the basic care assistance to these individuals and provide solid basis for planning public health policies. However, there are few references in the literature using the tools of spatial analysis in the context of disability. This dissertation was structured in the form of two papers. In the first article the global Moran's I index was used to characterize the spatial pattern of the rate of patients with genetic disease with physical disabilities in the AACD treatment of Pernambuco and the results were compared with those obtained with the randomization test. In both approaches we found the existence of spatial pattern for the rate of patients with genetic disease with physical disabilities in the treatment of Pernambuco AACD when we took into account the rates of four municipalities closest to each location. In the second article we evaluated the performance of the global Moran's I index and the Mantel test with Spearman correlation, both using randomization to assess the statistical significance, regarding the ability to detect spatial pattern for the rate of patients with diseases genetic with physical disabilities in the AACD treatment of Pernambuco. The results showed that the global Moran's I index proved to be a more satisfactory method for detecting the spatial pattern, since it uses the information in its calculations of the neighborhood, and provide greater control of the rejection rates of the null hypothesis under study. / Conhecer o padrão espacial dos portadores de doença genética com deficiência física em tratamento na AACD de Pernambuco é de grande importância, pois torna possível orientar a assistência aos cuidados básicos desses indivíduos e fornecer base sólida para o planejamento de políticas públicas de saúde. Entretanto, existem poucas referências na literatura utilizando o instrumental da análise espacial no contexto da deficiência física. A presente dissertação foi estruturada na forma de dois artigos científicos. No primeiro artigo o Índice I global de Moran foi utilizado para caracterizar o padrão espacial da taxa de pacientes portadores de doença genética com deficiência física em tratamento na AACD de Pernambuco e os resultados encontrados foram comparados com os obtidos através do teste de aleatorização. Em ambas as metodologias constatou-se a existência de padrão espacial agregado para a taxa de pacientes portadores de doença genética com deficiência física em tratamento na AACD de Pernambuco quando se levou em consideração as taxas dos 4 municípios mais próximos de cada localidade. No segundo artigo foi avaliado o desempenho do índice I global de Moran e do teste de Mantel com correlação de Spearman, ambos utilizando aleatorização para avaliar a significância da estatística, no que tange a capacidade de detectar padrão espacial para a taxa de pacientes portadores de doenças genéticas com deficiência física em tratamento na AACD de Pernambuco. Os resultados indicaram que o índice I global de Moran mostrou-se uma metodologia mais satisfatória para detectar do padrão espacial, uma vez que utiliza em seus cálculos as informações da vizinhança, além de proporcionar maior controle das taxas de rejeição da hipótese nula em estudo.
43

Structural studies of Norrin dependent Wnt/beta-catenin signaling

Chang, Tao-Hsin January 2014 (has links)
Norrin is a secreted cystine-knot growth factor that plays critical roles in vascular development in the brain, retina, and cochlea, as well as the uterus. Although Norrin is unrelated to the lipid-modified morphogens Wnts, Norrin activates the canonical Wnt/β-catenin pathway by binding to receptor Frizzled4 cysteine-rich domain (Fz4-CRD) and co-receptors of low density lipoprotein receptor related protein 5/6 ectodomain (Lrp5/6-ECD) in conjunction with Tetraspanin-12 (Tspan-12). Like Wnts, Norrin has limited extracellular diffusion properties as a result of associating with heparan sulfate proteoglycans (HSPGs). Mutations lead to inherited disordered retinal vascularization diseases such as Norrie disease, familial exudative vitreoretinopathy and coats' disease. However, the molecular mechanism of how Norrin initiates signalling by engagement with Fz4, Lrp5/6, and HSPGs has remained unresolved. Here, novel strategies for protein production of recombinant human Norrin and Fz4-CRD as well as the complex are developed. The crystal structures of Norrin and its complex with Fz4-CRD, plus complex bound with the heparin mimic sucrose octasulphate, and unliganded structures of Fz4-CRD are presented. These structural data together with biophysical and cellular assays not only reveal the Fz4 and Lrp5/6 binding sites on distinct patches of the Norrin surface, but also indicate the HSPGs binding site on Norrin and Fz4-CRD as well as providing a framework to explain numerous disease-related mutations. Structural comparison with Xenopus Wnt8 in complex with mouse Fz8-CRD provides molecular insights for our understanding of ligand-receptor binding specificity and promiscuity, which has important implications for developing therapeutic strategies against Norrin dependent retinal disorders, and cancers caused by abnormal Wnt signaling.
44

Identification de causes génétiques du syndrome d’Evans pédiatrique / Identifying genetic causes of pediatric Evans syndrome

Lévy, Eva 11 May 2016 (has links)
Le syndrome d'Evans est défini par l'existence concomitante ou séquentielle de cytopénies auto-immunes, le plus souvent, anémie hémolytique et thrombopénie immunologique. Chez l'enfant, il peut être secondaire à une infection, une maladie auto-immune systémique ou un déficit immunitaire primitif. Alternativement, chez une grande partie des patients, l'étiologie n'est pas clairement identifiée. Les patients atteints de syndrome d'Evans présentent parfois d'autres atteintes, telles une auto-immunité d'organe, une lymphoprolifération bénigne ou un déficit immunitaire. L'objectif de ce travail était d'identifier des causes génétiques chez des enfants présentant un syndrome d'Evans sans étiologie sous-jacente identifiée. Nous avons centré notre étude sur des formes sévères à début pédiatrique en faisant l'hypothèse qu'une maladie monogénique serait plus fréquente dans ce groupe de patients. Nous avons mis à profit les technologies de séquençage haut débit « nouvelle génération » (NGS) pour réaliser et analyser le séquençage de l'exome de patients et de certains de leurs apparentés afin de mettre en évidence des gènes candidats potentiels. Ce travail a permis l'identification de 4 gènes candidats : LRBA, CTLA-4, STAT3 (mutations gain de fonction) et NFKBIA. L'implication des 3 premiers gènes dans de nouvelles maladies monogéniques où l'auto-immunité est au premier plan a été confirmée par d'autres équipes au cours de ce travail. Pour chacun de ces gènes, nous avons poursuivi 2 objectifs complémentaires : d'une part, tenter de valider l'implication des gènes identifiés dans la maladie des patients. Nous avons pour cela utilisé des approches et techniques variées : biochimie et protéomique afin d'identifier des partenaires protéiques, microscopie confocale pour localiser les protéines et leurs interactions, tests cellulaires in vitro pour mettre en évidence un défaut fonctionnel, marquages en cytométrie en flux pour identifier des modifications dans les sous-populations lymphocytaires. D'autre part, nous avons recherché d'autres mutations de ces gènes chez des patients de phénotype clinique similaire. Nous avons ainsi constitué et exploré 3 cohortes de patients présentant des mutations de LRBA, CTLA-4 ou STAT3. Nous avons rassemblé une cohorte de 18 patients porteurs d'une mutation de LRBA, répartis dans 11 familles. Cela nous a permis de préciser et d'étendre le spectre clinique de cette maladie de découverte récente, avec en particulier des atteintes articulaires sévères s'associant à un diabète précoce, ou des entéropathies. Nous avons identifié 15 nouvelles mutations de transmission autosomique récessive dans le gène LRBA, codant une protéine de fonction inconnue dont l'absence entraine une maladie principalement caractérisée par une poly-auto-immunité. Nous avons identifié 29 partenaires protéiques potentiels de LRBA et précisé la localisation de LRBA dans les différents compartiments cellulaires. Nous avons également établi une cohorte de 12 patients dans 10 familles présentant un déficit en CTLA-4 par haplo-insuffisance. Au delà de la mise en évidence de 9 nouvelles mutations, nous avons décrit une famille où la variation est transmise de façon autosomique récessive. Dans les déficits en LRBA et CTLA-4, nous avons mis en évidence une diminution du pourcentage de lymphocytes T régulateurs parmi les PBMC et une diminution de l'expression de CTLA-4 dans les lymphocytes T activés. Ceci corrobore l'interaction entre ces 2 protéines décrite en parallèle par une autre équipe. Nous avons montré que les spectres cliniques des déficits en LRBA et CTLA-4, fortement chevauchant dans les premières descriptions publiées, pourraient se différencier, malgré l'implication des lymphocytes T régulateurs dans ces 2 maladies. (...) / Evans syndrome is defined by the occurence of autoimmune cytopenias, either at the same time or sequential, mainly autoimmune hemolytic anemia and immune thrombocytopenia. In children, it may be secondary to infections, systemic autoimmune disease, or primary immune deficiency, though in most patients, its etiology isn't obvious. Patients affected with Evans syndrome can also present other features, such as autoimmunity toward a particular organ, benign lymphoproliferation or immunodeficiency. The main goal of this work was to identify genetic causes in children presenting an Evans syndrome without a known underlying etiology. We focused our study on severe, early onset forms of the disease, with the hypothesis that a monogenic disease would be more frequent in this group of patients. Taking advantage of high throughput "Next Generation" sequencing (NGS) techniques, we sequenced and analyzed exome from patients and their relatives in search for adequate candidate genes. We identified 4 candidate genes: LRBA, CTLA-4, STAT3 (gain-of-function mutations), and NFKBA. Implication of the first 3 genes in new monogenic diseases with autoimmunity as a key feature was also confirmed by others during the course of this work. For each gene, we pursued 2 complementary goals: First, we sought to validate the implication of the gene in the patients' disease. To do so, we used various techniques and approaches: biochemistry and proteomics to identify protein partners, confocal microscopy to localize proteins and interactions, in vitro cellular assays to bring to light functional defect, flow cytometry to identify changes in lymphocytes subpopulations. We also looked for other mutations of each gene in patients with a similar clinical presentation. Hence we created and explored 3 cohorts of patients presenting with mutations of LRBA, CTLA-4 or STAT3. We constituted a cohort of 18 patients with LRBA mutations within 11 families. We then were able to precise and extend the clinical spectrum of this recently described disease. In particular, we observed patients with severe chronic arthritis associated with diabetes mellitus or enteropathies. We identified 15 new mutations of autosomal recessive transmission in the LRBA gene, coding a protein of unknown function, which absence is responsible for a disease mainly characterized by autoimmune features. We identified 29 candidate protein partners of LRBA and precized LRBA localisation in cell compartiments. We also established a cohort of 12 patients within 10 families presenting CTLA-4 haploinsufficiency. Beyond describing 9 new mutations, we report a family with autosomal recessive transmission.In LRBA and CTLA-4 deficiencies, we showed a decrease of regulatory T lymphocyte subset proportion among PBMC and a decrease of CTLA-4 expression in activated T cells. These results support the interaction between these 2 proteins, described concurrently by another team. We showed that the clinical spectra of these 2 diseases, although widely overlapping in first published reports, could be different despite a role of regulatory T cells in both. Hence, organ-specific autoimmunity and lymphoproliferation are more frequent in LRBA deficiency whereas granuloma and hypogammaglobulinemia are more present in CTLA-4 deficiency. Theses results suggests a role of genetic modifyers, which remain to identify. Among our cohort of patients with Evans syndrome, we also identified 5 patients within 5 families presenting gain-of-function mutations of STAT3. 3 of those mutations were reported by others during our work and appeared de novo in our patients. Functional validation of the 4th one is in progress. The last mutation follows a recessive transmission and could exemplify a new transmission modality of this disease. (...)
45

Transaldolase 1 is required for Neutrophil Extracellular Trap (NET) Formation

Morath, Jakob Paul 12 June 2020 (has links)
Transaldolase-Mangel (TALDO) ist ein extrem seltener, angeborener Stoffwechseldefekt, von dem weltweit nur 34 Fälle bekannt sind. Der Defekt geht auf den Verlust des Enzyms Transaldolase 1 aus dem nicht-oxidativen Pentosephosphat-Weg (nicht-oxPPW) zurück und äußert sich in einem weiten Spektrum klinischer Symptome. Die schwerwiegendsten Folgen sind Leber- und Nierenmangelfunktionen, die zum sehr frühen Tod führen können. Desweiteren leiden 15 % der Patienten an wiederkehrenden Infektionen. Neutrophile Granulozyten (Neutrophile) sind die häufigsten weißen Blutkörperchen im Menschen und essentiell für die angeborene Immunantwort gegen Infektionserreger. Ich habe hier funktionale Aspekte von TALDO-Neutrophilen untersucht. Der oxidative Pentosephosphat-Weg (oxPPW) stellt das Reduktionsäquivalent NADPH bereit, welches indirekt für die Entstehung von reactive oxygen species (ROS)-abhängigen Neutrophil Extracellular Traps (NETs) verantwortlich ist. Der Beitrag des nicht-oxPPW zur ROS-abhängigen NET-Bildung ist bislang nicht bekannt. In dieser Arbeit konnte ich für Neutrophile aus drei TALDO-Patienten eine jeweils komplett abwesende Entstehung ROS-abhängiger NETs und einen deutlich verringerten oxidativen Burst nach PMA-Stimulation zeigen. Um diese Beobachtungen in einem unabhängigen Modelsystem zu bestätigen, habe ich mit Hilfe des CRISPR-Cas9-Systems, ‚knock-out‘ Mutanten von Transaldolase 1 und dessen Partnerenzym Transketolase in der Neutrophil-ähnlichen Zelllinie PLB-985 hergestellt. Die dergestalt genetisch manipulierten Zellen waren nicht mehr zu PMA-induziertem Zelltod in der Lage. Dies ist somit der erste genetische Beweis für die Abhängigkeit des oxidativen Burst und der Bildung von NETs vom nicht-oxPPW. Diese Erkenntnis trägt zum einen zum mechanistischen Verständnis der NET-Entstehung bei und liefert zum anderen eine potentielle Erklärung für einige der bei TALDO beobachteten Symptome. Desweiteren wurden einige der metabolischen Erfordernisse für die Bildung von NETs mit Hilfe von Inhibitoren untersucht. Die erhaltenen Erkenntnisse zeigen, dass das initiale Maximum des oxidativen Bursts für NET-Bildung unerheblich ist und vielmehr die ROS-Generierung nach ca. 50 Minuten entscheidende Bedeutung für diese hat. / Transdaldolase 1-deficiency (TALDO) is a rare genetic disease with only 34 described cases globally. Transaldolase 1 is part of the non-oxidative pentose phosphate pathway (PPP) and its deficiency results in many clinical symptoms including kidney and liver failure, which can lead to early child-mortality. Some of these patients suffer from recurrent infections, for example in the respiratory tract. Neutrophils are the most abundant white blood cells and essential for the innate immune defence against bacterial and fungal pathogens. The PPP generates reduced NADPH that is crucial for the generation of superoxide by the NADPH oxidase NOX2. In turn, NOX2 is essential for neutrophil extracellular trap (NET) formation. NETs occur through the neutrophil-specific cell death netosis and consist of chromatin decorated with granular proteins. Here I report that neutrophils of three TALDO patients did not make NETs. Deletion of transaldolase 1, and its partner enzyme transketolase, in the neutrophil-like PLB-985 cell line reduced ROS generation and cell death. This confirms that transaldolase 1 is required for NET formation. We present, to the best of our knowledge, the first genetic evidence that the non-oxidative PPP is required for ROS generation and NET formation. Furthermore, some of the metabolic requirements for NET formation were assessed. The obtained data indicate that the initial peak of the oxidative burst is irrelevant for NET formation but the ROS generation after 50 minutes on the contrary has crucial significance.

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