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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

Efeitos da associação do sistema pré-MIV com NPPC com MIV suplementada de modo sequencial com LH sobre a produção in vitro de embriões bovinos

Pronunciate, Micheli January 2019 (has links)
Orientador: Marcelo Fabio Gouveia Nogueira / Resumo: In vivo, a maturação oocitária é gonadotrofina-dependente (FSH e LH) e, até haver o devido estímulo, o oócito é mantido em parada meiótica (prófase I) devido à manutenção dos níveis intraoocitários de cAMP. O FSH é o responsável pelo crescimento inicial do folículo antral enquanto o LH promove a maturação final oocitária (no estágio pós-desvio), sinalizando a produção de peptídeos EGF-like (fator de crescimento semelhante ao epidermal) nas células da granulosa. Estes se ligam ao seu receptor (EGFR) nas células do cumulus ativando a via da proteína cinase ativadora de mitógeno (MAPK), causando o fechamento das junções comunicantes do tipo GAP e culminando na retomada meiótica. Os peptídeos AREG (Ampirregulina)e EREG (Epirregulina) são utilizados na maturação in vitro em diferentes espécies e em substituição ou associação com o FSH. Alguns estudos demonstram que, quando maturados com esses peptídeos, os oócitos desenvolvem embriões de melhor qualidade, com maior número de células da massa celular interna e mais parecidos com aqueles maturados in vivo. No entanto, o oócito retirado do microambiente folicular retoma a meiose espontaneamente, de forma precoce e não sincronizada entre o núcleo e o citoplasma. Para melhorar os resultados da maturação in vitro, é importante retardar a retomada espontânea meiótica. A literatura descreve a eficácia do precursor do peptídeo natriurético tipo C (NPPC) em manter in vitro a concentração de cAMP oocitária similar à fisiológica. Diante disso... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In vivo, the oocyte maturation is gonadotropin-dependent (LH and FSH) and, until there is a due stimulation, the oocyte is maintained in meiotic arrest (prophase I) due to the maintenance of intra-oocyte levels of cAMP. The FSH is responsible for initial growth of the antral follicle while the LH promotes final oocyte maturation (post-deviation), signaling the production of EGF-like (Epidermal Growth Factor-like) peptides in the granulosa cells. They bind to their receptor (EGFR) on cumulus cells activating the mitogen-activating protein kinase (MAPK) pathway causing closure of Gap Junctions culminating in meiosis resumption. The AREG (amphiregulin) and EREG (epiregulin) peptides are used in vitro maturation in different species and in substitution or association with FSH. Same studies shown that when mature with these peptide, oocytes develop better-quality embryos, with more cells in the inner cell mass, and more similar to those in vivo. However, the oocyte removed from the follicular microenvironment, resumes meiosis spontaneously, early and not synchronized between the cytoplasm and nucleus. To improve the in vitro maturation results, it is important delay spontaneous meiotic resumption. The literature describes the efficacy of the C-type natriuretic peptide (NPPC) precursor in maintaining the physiological-like oocyte cAMP concentration in vitro. In this study, the effect of AREG on the abundance of oocyte and cumulus cell transcript was observed, as well as its effect ... (Complete abstract click electronic access below) / Mestre
2

Disease Tolerance, Epigenetic Inheritance, and Surviving Pathogenic Viral Infections

Silverstein, Noah J. 18 August 2021 (has links)
Health is often defined in terms of absence of disease or pathological processes, but this is a definition of exclusion and incomplete. For example, SARS-CoV-2 viral load does not reliably predict disease severity, and so individuals must vary in their ability to control inflammation and maintain normal tissue homeostasis. This host defense strategy is called disease tolerance, and better understanding of disease tolerance mechanisms could change the way that we treat disease and work to maintain health. The first project presented in this dissertation found that after accounting for effects of age and sex, innate lymphoid cells (ILCs), but not T cells, were lower in adults and children sick with COVID-19 or MIS-C, independent of lymphopenia. Furthermore, abundance of ILCs, but not of T cells, correlated inversely with disease severity. These blood ILCs were shown to produce amphiregulin, a protein implicated in disease tolerance and tissue homeostasis, and the percentage of amphiregulin-producing ILCs was lower in males. These results suggest that, by promoting disease tolerance, homeostatic ILCs decrease morbidity and mortality associated with SARS-CoV-2 infection, and that lower ILC abundance accounts for increased COVID-19 severity with age and in males. The second project describes a novel mouse model of epigenetic inheritance wherein paternal influenza A virus (IAV) infection results in less severe influenza disease in IAV infected offspring. This offspring phenotype was not attributable to differences in viral load, indicating a possible difference in disease tolerance. Paternal caloric deprivation decreased, and influenza B virus infection increased, offspring influenza disease severity, and in vitro fertilization demonstrated sperm are sufficient to transfer IAV-associated epigenetic inheritance phenotypes. These findings represent a foundation for further work that, by continuing to elucidate the mechanisms of disease tolerance and epigenetic inheritance, could provide novel therapeutic interventions to help promote and maintain health.
3

Репрезентация национальной культуры в книгоиздании Армении : магистерская диссертация / Representation of national culture in Armenian publishing industry

Унанян, Д. А., Unanian, D. A. January 2019 (has links)
Master’s thesis “Representation of national culture in Armenian publishing industry” consists of two chapters. First chapter examines definitions essential to the research; characterizes major book market participants in Armenia; defines key trends in Armenian publishing industry. Second chapter is devoted to the analysis of publications issued by Armenian publishing houses; identification of means of representation of national culture in Armenian publishing industry and publications, such as content methods related to choosing particular topics – about history, Armenian culture, genocide, publications for diaspora, translated editions adapted for Armenian realities; visual and printing methods – design of translated and Armenian publications, which use national ornaments, national costumes, household items not only as informative illustrations, but also as book design elements not related directly to description of ornaments, costumes etc. Bibliography consists of 86 source materials. / Магистерская диссертация «Репрезентация национальной культуры в книгоиздании Армении» состоит из двух глав. В первой главе рас-сматриваются понятия, необходимые для исследования; характеризуются основные участники книжного рынка Армении; определяются ключевые тенденции книгоиздания Армении. Во второй анализируются выпускаемые армянскими издательствами издания; выявляются способы репрезентации национальной культуры в изданиях и издательской деятельности Армении, а именно: контент-способы, связанные с подбором определенных тем – об истории, культуре Армении, геноциде, издания для диаспоры, переводные издания, адаптируемые под армянские реалии; визуально-полиграфические способы – оформление переводных и армянских изданий, в котором используются национальные орнаменты, народные костюмы, бытовые элементы не только в качестве информативных иллюстраций, но и как элементы дизайна книг, не связанных напрямую с описанием орнаментов, костюмов и т. д. Библиографический список содержит 86 наименований.
4

How to Obtain a Mega-Intestine with Normal Morphology: In Silico Modelling of Postnatal Intestinal Growth in a Cd97-Transgenic Mouse

Hofmann, Felix, Thalheim, Torsten, Rother, Karen, Quaas, Marianne, Kerner, Christiane, Przybilla, Jens, Aust, Gabriela, Galle, Joerg 11 December 2023 (has links)
Intestinal cylindrical growth peaks in mice a few weeks after birth, simultaneously with crypt fission activity. It nearly stops after weaning and cannot be reactivated later. Transgenic mice expressing Cd97/Adgre5 in the intestinal epithelium develop a mega-intestine with normal microscopic morphology in adult mice. Here, we demonstrate premature intestinal differentiation in Cd97/Adgre5 transgenic mice at both the cellular and molecular levels until postnatal day 14. Subsequently, the growth of the intestinal epithelium becomes activated and its maturation suppressed. These changes are paralleled by postnatal regulation of growth factors and by an increased expression of secretory cell markers, suggesting growth activation of non-epithelial tissue layers as the origin of enforced tissue growth. To understand postnatal intestinal growth mechanistically, we study epithelial fate decisions during this period with the use of a 3D individual cell-based computer model. In the model, the expansion of the intestinal stem cell (SC) population, a prerequisite for crypt fission, is largely independent of the tissue growth rate and is therefore not spontaneously adaptive. Accordingly, the model suggests that, besides the growth activation of non-epithelial tissue layers, the formation of a mega-intestine requires a released growth control in the epithelium, enabling accelerated SC expansion. The similar intestinal morphology in Cd97/Adgre5 transgenic and wild type mice indicates a synchronization of tissue growth and SC expansion, likely by a crypt density-controlled contact inhibition of growth of intestinal SC proliferation. The formation of a mega-intestine with normal microscopic morphology turns out to originate in changes of autonomous and conditional specification of the intestinal cell fate induced by the activation of Cd97/Adgre5.

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