Zugl.: Giessen, Universiẗat, Diss., 2004.

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published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy

Glaucoma is a devastating blinding disease, caused by retinal ganglion cell (RGC) loss via apoptosis and clinically associated with raised intraocular pressure (IOP). Mainstream theories of glaucoma's pathogenesis detail loss of RGCs via indirect links to lOP; including mechanodistortion of optic nerve axons, trophic factor deficiency, ischaemia or excitotoxicity. A novel concept in the pathogenesis of glaucoma is that pressure alone could be a direct stimulus for RGC loss. Currently available glaucoma treatments are solely aimed at lowering lOP. Reduction ofIOP has been shown to reduce glaucomatous progression however RGC losses continue. Neuroprotection is an emerging field of research offering hope to neurodegenerative diseases, including glaucoma. This thesis investigated known glaucoma therapeutics with suggested neuroprotective activity in an in vitro glaucoma model using the RGC-5 cell line. To evaluate therapies, a suitable in vitro model was initially evaluated. The RGC-5 cell line was immunochemically demonstrated to possess NSE, a neuronal marker and Thy-1, an RGC marker. Glutamate excitotoxicity was investigated however excessive concentrations were required to cause significant in vitro RGC-5 cytotoxicity. Using a modified hydrostatic pressure model, reproducible pressure-induced RGC-5 apoptosis was demonstrated. Apoptosis was detected using cell morphology and confirmed with both early (caspase-3 and annexin V) and late (TUNEL) apoptotic markers. Despite the advantages of rapid, objective quantification, results indicated that flow cytometry of RGC-5 cells was not technically possible. I defined a modified laser scanning cytometry protocol, allowing for objective apoptosis quantification of TUNEL stained cells. Brimonidine is postulated to mediate receptor mediated RGC protection. Experiments conducted for this thesis, were the first to immunochemically demonstrate alpha2 adrenergic receptor expression on human RGCs and the RGC-5 cell line, suggesting direct cell mediated protection on the target neuron of glaucoma is possible and that the RGC-5 line is a useful in vitro target for experimentation. Both brimonidine and betaxolol were shown to confer protection to the RGC-5 cell line from pressure-induced apoptosis, under defined conditions. These results suggest that these drugs may confer direct cell-mediated protection, rather than indirect protection conferred via other retinal or glial cells, the anterior segment, the vasculature or some other means.

Thesis (Ph. D.)--University of Hong Kong, 1994. / Includes list of author's publication (leaves viii-xiv). Includes bibliographical references (leaves 253-281).

In order to understand biological intelligence I wanted to map the simplest example that could still demonstrate learning. Learning, or classical conditioning, has long been shown to occur in decapitated insects, hence this was a logical target, specifically the most studied insect, the fruit fly (Drosophila melanogaster). This learning occurs in the insect equivalent of the spinal cord, referred to as the ventral nervous system (VNS). The initial task was to resolve the gross neuroanatomy of the VNS. Standardising the neuroanatomical regional boundaries into 3D painted domains, clarifying textural descriptions, as well as matching the literature synonyms, were all combined into the Drosophila nomenclature. This enables existing knowledge, from the literature, to be easily queried as well as providing a basis for future additions. These clarified anatomical definitions were agreed by a workshop of researchers with experience in the VNS. Definitions will be published to form the basis for a more detailed nomenclature to be developed upon. In order to combine 3D images taken from different flies, a template was chosen, and an alignment pipeline tool devised. This alignment pipeline enabled samples of secondary lineages, that make up the bulk of the neurons in the VNS, to be aligned. This lineage atlas provided fixed internal boundary points for the neuroanatomy to be defined against. Previous work has provided detailed information on these lineages, as well as showing their likely homologous relationship as a gross functional unit within behavioural circuits. By constructing a spatial atlas of these lineages, a gross connection plan can be devised, targeting future research. This lineage atlas, in combination with NBLAST, enables the identification of single neurons to their developmental origin simply by using their morphology. The template with neuroanatomical definitions has been made publicly available via VirtualFlyBrain.org (VFB) and FlyBase.org. The alignment pipeline has been made available via a web interface for researchers to align their own data to the any of the VFB templates. This project provides an anatomical and developmental gross map of the VNS to enable greater development of the connectome.

Le porcelet a un système immunitaire immature à la naissance, ceci est compensé par la protectionsystémique (colostrum) et humoral (lait) de la mère. Cette immunité passive n’est pas le seul transfertmaternel, la microflore et probablement d’autres substances humorales sont aussi transmis, favorisant ledéveloppement de la réponse immune en Immunoglobuline A (IgA).Lors d’un élevage conventionnel, la réponse IgA se développe autour de 3 semaines. La question est desavoir quelle est l’influence de la durée de lactation sur le développement de l’intestin du jeune porcelet. Pourcela, nous avons définis 3 groupes de porcelets sevrés à 1, 2 et 3 semaines et un groupe contrôle non sevré.Nous avons étudié en cinétique à 7, 14, 21 et 28 jours la concentration en IgA du sang et la microfloreintestinale. De plus, l’analyse du répertoire VDJ (chaîne lourde) des IgA a été réalisée à 28 jours.Les résultats montrent qu’une lactation très réduite (à 1 semaine) provoque, à 21 jours, une déficienceen IgA sériques (spécifiques et totaux) et une diversification de la flore. Il en résulte une plus grande diversitédu répertoire IgA dans le ganglion mésentérique. / The neonate piglet has an immature immune system, consequently it receives from its mother asystemic and local mucosal protect via the colostrum and milk respectively. The mother is not contribute onlyby passive immunity but also by transmission of microflora and presumably other humoral substancesfavouring the onset of Immunoglobulin A (IgA) immune response.As IgA response increased in conventional breeding, i.e at 3 weeks of age, we ask the question of theinfluence of suckling onto the IgA development in neonatal gut. For that purpose we defined 3 groups ofpiglets weaned at 1, 2 and 3 weeks and 1 group no weaned. We looked IgA products in blood and intestinalmicroflora at days 7, 14, 21, 28 and the IgA heavy VDJ repertoire development at the same age, day 28.The results show that very short suckling (1 week only) led to lower seric IgA (specific and total)concentration and higher flora diversity, at day 21 and consequently larger IgA diversity in the mesentericlymph node (MLN).

No description available.

Thesis (M.S.)--University of Michigan, 2002. / Includes bibliographical references.

published_or_final_version / abstract / Anatomy / Doctoral / Doctor of Philosophy