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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

Ironing out the pathophysiology of neurodegeneration with brain iron accumulation (NBIA) : clinical investigations and disease modelling yield novel evidence of systemic dysfunction and provide a robust and accurate disease model of NBIA

Minkley, Michael 01 May 2018 (has links)
Neurodegeneration with Brain Iron Accumulation (NBIA) disorders, such as Phospholipase A2G6-Associated Neurodegeneration (PLAN) and Pantothenate Kinase-Associated Neurodegeneration (PKAN), are a group of rare early-onset, genetic disorders characterized by neurodegeneration and iron accumulation inside of the basal ganglia (BG), which is accompanied by progressive motor symptoms. In order to address the limitations in available models of NBIA, a B6.C3-Pla2g6m1J/CxRwb mouse model of PLAN was characterized. This model demonstrated key hallmarks of the disease presentation in NBIA, including a severe and early-onset motor deficit, neurodegeneration inside of the substantia nigra (SN) including a loss of dopaminergic function and the formation of abnormal spheroid inclusions as well as iron accumulation. The capture of these hallmarks of NBIA makes this an ideal animal research model for NBIA. Additionally, exploration of candidate systemic biomarkers of NBIA was performed in a case study of a patient with PLAN and in a cohort of 30 patients with PKAN. These investigations demonstrated reductions in transfer and slight, but not significant elevations in soluble transferrin receptor. No significant difference was seen in serum iron parameters. A systemic disease burden including chronic oxidative stress; elevated malondialdehyde, and inflammation; elevated C-reactive protein (CRP), IL-6 and TNFα was noted in both investigations. A number of candidate protein biomarkers including: fibrinogen, transthyretin, zinc alpha-2 glycoprotein and retinol binding protein were also identified. These markers correlated with measures of the severity of iron loading in the globus pallidus (GP); based on R2* magnetic resonance imaging (MRI) and the severity of motor symptoms (Barry-Albright Dystonia Rating Scale) making them potential candidates markers of dysfunction in NBIA. In the patient with PLAN, 37 weeks of therapy with the iron chelator deferiprone (DFP) as well as 20 months of therapy with the antioxidants alpha lipoic acid (ALA) and n-acetylcysteine (NAC) were efficacious in reducing the systemic oxidative and inflammatory disease burden, but it did not significantly alter the progression of the disease. In the antioxidant therapy, this efficacy was primarily due to ALA. When the cohort of patients with PKAN were treated with DFP for 18 months it was highly efficacious in lowering brain iron accumulation in the GP. No significant reduction in the speed of disease progression was seen in DFP treated patients compared to placebo based on initial analysis. Similar to the PLAN patient, DFP also mitigated the systemic disease burden in PKAN patients. In both cases DFP was well tolerated and had minimal impact on serum iron levels, TIBC and transferrin saturation. Collectively these investigations provide valuable insights into disease progression in NBIA. They also provide tools to aid further investigations in NBIA. These are provided in the form of a well-characterized B6.C3-Pla2g6m1J/CxRwb model of PLAN, which robustly captures the disease presentation seen in patients, as well as a panel of systemic blood-based markers of disease burden in NBIA and candidate markers of dysfunction in NBIA. These markers were used to assess two novel therapies in NBIA chelation with DFP and antioxidant therapy with ALA and NAC. / Graduate / 2019-04-19
2

Controle genético da coloração do tegumento e da concentração de ferro em sementes de feijão mesoamericano e andino / Genetic control of seed coat colorand of iron concentration in middle american and andean common bean seeds

Possobom, Micheli Thaise Della Flora 24 February 2014 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The acceptance of the beans by consumers is related to seed coat color and nutritional value. The objectives of this work were: (1) to verify the existence of maternal effect for the color parameters "L", a* and b* and for the iron concentration in Middle American and Andean common bean seeds; (2) to investigate the distribution of iron in the seed coat and embryo of the Middle American and Andean common bean seeds; (3) to estimate heritability and gain with the selection for the parameters "L", a* and b* and for the iron concentration in common bean seeds of different gene pools; and (4) to select recombinant with seed coat color of highest commercial demand and with high iron concentration in the seeds. To do this, were performed controlled crosses between Middle American lines CNFP 10104 and CHC 01-175, and Andean lines Cal 96 and Hooter to obtain F1, F1 reciprocal, F2, F2 reciprocal and backcrosses (RC11 e RC12) generations for each hybrid combination. Parents and generations obtained were evaluated in two field experiments (normal rainy and dry season) in Santa Maria - RS. Significant maternal effect was obtained for all color parameters in the Middle American and Andean gene pool. In CNFP 10104 x CHC 01-175 crossing high broad sense heritability estimates were obtained for luminosity (h2b: 76.66 to 78.09%), chromaticity a* (h2b: 73.08 to 89.31%) and chromaticity b* (h2b: 88.63 to 90.11%) values in normal rainy and dry season. In Cal 96 x Hooter crossing the parameters luminosity (h2b: 95.07%), chromaticity a* (h2b: 86.19%) and chromaticity b* (h2b: 92.50%) showed high broad sense in dry season. For iron concentration, maternal effect was significant only for the Middle American gene pool. The iron concentration was higher in seed coat of Middle American lines, and superior in embryo of Andean lines. Estimates of narrow sense heritability for the iron concentration of 54.69% and broad sense heritability of 70.20% for CNFP 10104 x CHC 01-175 crossing and broad sense heritability of 62.27% for Cal 96 x Hooter crossing were observed. A F2 plant with iron concentration of 132.99 mg kg- 1 of dry matter was obtained from CNFP 10104 x CHC 01-175 crossing. The selection of F3 seeds (seed coat in F2) from the crossings performed should be promising to obtain common bean lines with seeds colored according to the market demand and with high iron concentration in seeds. / A aceitação dos grãos de feijão pelos consumidores está relacionada à coloração do tegumento e ao valor nutricional. Assim, foram objetivos desse trabalho: (1) verificar a existência de efeito materno para os parâmetros de coloração L , a* e b* e a concentração de ferro em sementes de feijão Mesoamericano e Andino; (2) investigar a distribuição do ferro no tegumento e no embrião das sementes de feijão Mesoamericano e Andino; (3) obter estimativas de herdabilidade e de ganho com a seleção para os parâmetros L , a* e b* e para a concentração de ferro em sementes de feijão de diferentes grupos gênicos; e (4) selecionar recombinantes com coloração de tegumento de maior demanda no comércio e com alta concentração de ferro nas sementes de feijão. Para tanto, realizaram-se cruzamentos controlados entre as linhagens Mesoamericanas CNFP 10104 e CHC 01-175 e entre as linhagens Andinas Cal 96 e Hooter para a obtenção das gerações F1, F1 recíproco, F2, F2 recíproco e retrocruzamentos (RC11 e RC12) para cada combinação híbrida. Os genitores e as gerações obtidas foram avaliados em dois experimentos a campo (safra e safrinha) em Santa Maria - RS. Efeito materno significativo foi obtido para todos os parâmetros de coloração no grupo Mesoamericano e Andino. No cruzamento CNFP 10104 x CHC 01-175 foram obtidas estimativas de herdabilidade em sentido amplo de alta magnitude, nos cultivos de safra e de safrinha, para os valores de luminosidade (h2a: 76,66 a 78,09%), cromaticidade a* (h2a: 73,08 a 89,31%) e cromaticidade b* (h2a: 88,63 a 90,11%). No cruzamento Cal 96 x Hooter, também, se obteve alta herdabilidade em sentido amplo, no cultivo de safrinha, para luminosidade (h2a: 95,07%), cromaticidade a* (h2a: 86,19%) e cromaticidade b* (h2a: 92,50%). Para a concentração de ferro foi observado efeito materno significativo somente para o grupo Mesoamericano. A concentração de ferro nas sementes de feijão foi maior no tegumento das linhagens Mesoamericanas e no embrião das linhagens Andinas. Estimativas de herdabilidade para a concentração de ferro em sentido restrito de 54,69% e em sentido amplo de 70,20% foram observadas para o cruzamento CNFP 10104 x CHC 01-175 e em sentido amplo de 62,27% para o cruzamento Cal 96 x Hooter. Uma planta F2 com concentração de ferro de 132,99 mg kg-1 na matéria seca foi obtida a partir do cruzamento CNFP 10104 x CHC 01-175. A seleção de sementes F3 (tegumento em F2) a partir dos cruzamentos realizados deverá ser promissora para a obtenção de linhagens de feijão com coloração de tegumento com maior demanda no comércio e com alta concentração de ferro nas sementes.

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