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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.
71

Estudo molecular do gene FANCA em pacientes com quadro clínico de Anemia de Fanconi / Molecular study of the gene FANCA in patients with compatible clinical of Fanconi Anemia

Gonçalves, Claudia Estela, 1970- 27 August 2018 (has links)
Orientador: Carmen Sílvia Bertuzzo / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-27T12:57:33Z (GMT). No. of bitstreams: 1 Goncalves_ClaudiaEstela_D.pdf: 2258187 bytes, checksum: 7cac2852cc031e31eba1a31c62d9dda2 (MD5) Previous issue date: 2014 / Resumo: A Anemia de Fanconi (AF) é uma alteração genética caracterizada por múltiplas anomalias congênitas, anormalidades hematológicas e predisposição a uma variedade de tumores. A incidência mundial da AF em todo o mundo é de aproximadamente três por milhão e a frequência de heterozigotos é estimada em um para 300 na Europa e Estados Unidos. É uma doença causada por mutações em genes relacionados ao sistema de reparo. Até o momento foram descritos 16 genes que podem estar multados. São eles: FANCA, FANCB, FANCC, FNCD1, FANCD2, FANCE, FANCF, FANCG, FANCI, FANCJ, FANCL, FANCM, FANCN, FANCO, FANCP E PANCQ. Os grupos mais frequentes são o FANCA e FANCC. De qualquer modo devido a essa heterogeneidade gênica, o diagnóstico molecular dessa alteração é complexo. Com o intuito de testar uma estratégia diagnóstica, o presente trabalho se propôs a identificar as mutações mais frequentes no gene FANC por PCR e digestão enzimática e investigar mutações no gene FANCA, por meio da Reação em Cadeia da Polimerase seguida de digestão enzimática da mutação Brasileira e posterior sequenciamento dos 43 éxons em 60 pacientes portadores de Anemia de Fanconi DEB positivos. Foram detectados 19 pacientes (27,94%), como sendo do grupo C e 16 pacientes como grupo A (23,53%). A mutação ?3788-3790 do gene FANCA teve uma frequência alélica de 15,4%. Foram encontradas 3 mutações intrônicas, 1 mutação sinônima e 1 mutação de sentido trocado no gene FANCA. Não foram encontradas correlações com as manifestações hematológicas, renais, baixo peso, malformações congênitas de membros, machas e pigmentação de pele, sexo e idade / Abstract: The Fanconi Anemia (FA) is a genetic disorder characterized by multiple congenital and hematological abnormalities and predisposition to a variety of tumors. The worldwide incidence of AF is approximately three per million and the frequency of heterozygotes is estimated at one in 300 in Europe and the United States. It is a disease caused by mutations in genes involved in the repair system. So far have been described 16 genes that may be mutated. They are: FANCA , FANCB , FANCC , FNCD1 , FANCD2 , FANCE , FANCF , FANCG , FANCI , FANCJ , FANCL , FANCM , FANCN , FANCO , FANCP And PANCQ . The most common groups are the FANCA and FANCC. However due to this genetic heterogeneity, molecular diagnosis of this change is complex. In order to test a diagnostic strategy, the present study aimed to identify the most frequent mutations in the FANC gene by PCR and restriction enzyme digestion and investigate mutations in the FANCA gene, using the polymerase chain reaction followed by enzymatic digestion of the mutation Brazilian and subsequent sequencing of the 43 exons in 60 patients with Fanconi Anemia positive DEB. 19 patients (27.94%) were detected as group C and 16 patients as group A (23.53%). The ?3788 - 3790 mutation in the FANCA gene had an allelic frequency of 15.4%. Three intronic mutations, one synonymous mutation and one mutation changed direction in FANCA gene were found. No correlation with hematologic, renal, low weight manifestations of congenital malformations members, butches and skin pigmentation, age and sex were found / Doutorado / Clinica Medica / Doutora em Clínica Médica
72

Studium regulace a funkce DNA-opravných enzymů UBE2T a FANCL / Study of regulation and function of DNA repair enzymes UBE2T and FANCL

Hušková, Andrea January 2019 (has links)
Due to the action of endogenous and exogenous agents, DNA is subject up to 70,000 lesions per day, thus the existence of repair mechanisms and enzymes is more than necessary. We know basic mechanisms of several specific DNA repair pathways, of which the Fanconi anaemia (FA) repair pathway is one of the least explored. FA is a rare, autosomal recessive disorder characterized by early onset bone marrow failure, developmental defects, genomic instability and predisposition to acute myeloid leukaemia and solid tumours. The primary diagnosis of FA is a hypersensitivity to cross-linking agents of DNA due to inactivation of one of the 21 genes from the FA repair pathway, the so-called FANC genes (FA complementation group). The molecular defect in FA is an impaired repair of DNA interstrand cross-links (ICLs). The ICLs are cytotoxic lesions that inhibit the process of DNA replication and transcription. A crucial step in the FA pathway that initiates ICL repair is a monoubiquitination of FANCD2. FANCD2 monoubiquitination is a base for the recruitment of additional proteins that coordinate DNA repair. Ubiquitin is recruited via activating enzyme E1 (UBA1), ubiquitin-conjugating enzyme E2T (UBE2T) and transferred onto FANCD2 by multisubunit E3 ligase (FA core complex). There are up to 11 different proteins...
73

Regulation and Targeting of the FANCD2 Activation in DNA Repair

Caceres, Valentina Celeste 01 January 2015 (has links)
Fanconi anemia (FA) is a genome instability syndrome that is clinically manifested by bone marrow failure, congenital defects, and elevated cancer susceptibility. The FA pathway is known to regulate the repair of DNA interstrand crosslinks in part through DNA homologous recombination (HR) repair. Up to today 16 FA proteins have been discovered that may participate in the common pathway. Cells that have mutations in the FA genes are hypersensitive to DNA damaging agents and display chromosome instability. A key regulatory event in the FA pathway is monoubiquitination of FANCD2-FANCI heterodimer that is mediated by a multi-component E3 ubiquitin ligase complex called FA core complex. Current model suggests that once the FANCD2-FANCI heterodimer is monoubiquitinated it relocates to chromatin where it interacts with other key repair proteins to facilitate DNA repair. More than 90% of the FA cases are presumed to be associated with defects in the monoubiquitination reaction, suggesting the significance of the modification in the pathogenesis of the disease. Despite the significance, the molecular interplay between the FA core complex and the FANCD2-FANCI heterodimer remains enigmatic. We are interested in the assembly mechanism of the various FA subcomplexes into the core complex, and we are actively investigating how the FANCD2-FANCI heterodimer is recruited to these putative subcomplexes. As the FA pathway is a crucial determinant for cellular resistance to DNA damaging agents, there have been hypotheses that disruption of this pathway may be beneficial in enhancing chemosensitivity of certain cancer cells. In collaboration with Dr. Cai’s chemistry lab, we will develop a screen platform to identify a small molecules to interrupt the monoubiquitination reaction. Completion of these studies will enhance the much-needed knowledge of the key enzymatic reaction in the pathway, and perhaps the information can be used for development of novel chemotherapeutic strategies.
74

Regulation of the Fanconi Anemia Pathway by Deubiquitination

Yang, Kailin January 2012 (has links)
Fanconi anemia (FA) is a rare genetic disease characterized by bone marrow failure and cancer predisposition. Cell lines derived from FA patient exhibit chromosomal instability and sensitivity to DNA interstand crosslinkers (ICLs) like mitomycin (MMC). The key event in Fanconi anemia pathway is the regulated ubiquitination and deubiquitination of FANCD2 and FANCI. Upon DNA damage, FANCD2 and FANCI are monoubiquitinated by FA core complex. They then move into the chromatin and serve as the landing site for downstream players, like FANCP/SLX4 and FAN1. USP1, the deubiquitinating enzyme (DUB), removes ubiquitin from FANCD-Ub/FANCI-Ub, and this step is required for the integrity of FA pathway. This dissertation addresses how USP1 is regulated in the cell. In Chapter 2, we discovered UAF1/WDR48 as a critical binding partner for USP1, by activating its enzymatic activity in vitro and in vivo. We then generated DT40 knockout cell lines of USP1 and UAF1. We showed that USP1/UAF1 complex is functionally required for homologous recombination (HR). Interestingly, PCNA-Ub is also a substrate for USP1. We discovered that hELG1, through its binding to USP1/UAF1 complex, regulates the deubiquitination of PCNA-Ub and translesion DNA synthesis (TLS). Then in Chapter 3, we discovered a tandem repeat of SUMO-like domains (SLD1 and SLD2) in the C terminus of UAF1. SLD2 binds directly to a SUMO-like domain-interacting motif (SIM) on FANCI. Deletion of the SLD2 of UAF1 or mutation of the SIM of FANCI disrupts UAF1/FANCI binding and inhibits FANCD2 deubiquitination. The SLD2 sequence of UAF1 also binds to a SIM on hELG1, and targets the USP1/UAF1 complex to its PCNA-Ub substrate. We proposed the regulated targeting of USP1/UAF1 to its DNA repair substrates, FANCD2-Ub and PCNA-Ub, by SLD-SIM interactions coordinates HR and TLS. Originating from USP1/UAF1 complex, we worked out a general mechanism of DUB regulation by WD40 proteins, which involved in two more DUBs, USP12 and USP46 (discussed in Chapter 4 and Appendix A). Lastly in Chapter 5, through bioinformatic analysis we identified a series of novel proteins containing ubiquitin-binding zinc fingers (UBZ). We then focused on SNM1A and FAAP20/C1orf86, and characterized their function in DNA crosslink repair.
75

Reprogramming Pediatric Genetic Disorders: Pearson Syndrome, Ring 14 Syndrome, and Fanconi Anemia

Cherry, Anne Blanche Cresswell 04 June 2015 (has links)
The effect of a single genetic mutation can vary greatly between different types of cells. The mutated gene may not be expressed in one tissue but may cause a devastating loss of function in another. To learn about disease mechanisms and generate novel therapies, genetic disorders must be studied in the types of cells where the mutations are most deleterious. Recently, scientists have begun manipulating cellular identity to create the cell types most affected by various genetic diseases. This dissertation describes the experience of generating reprogramming models for three genetic disorders: Ring 14 syndrome, Pearson syndrome, and Fanconi anemia.
76

Loss of rad51 in zebrafish (Danio rerio) : a novel Fanconi anaemia model

Botthof, Jan Gregor January 2017 (has links)
RAD51 is an indispensable homologous recombination protein, necessary for strand invasion and crossing over. It has recently been designated as a Fanconi anaemia (FA) gene, following the discovery of two patients carrying dominant negative mutations. FA is a hereditary DNA repair disorder characterised by various congenital abnormalities, progressive bone marrow failure and cancer predisposition. The cellular and molecular pathology of FA is poorly understood, resulting in a severe lack of effective treatment options. In this thesis, I describe the first viable vertebrate model of RAD51 loss. Phenotypic characterisation of zebrafish rad51 loss-of-function mutants showed that they develop key features of FA, including hypocellular kidney marrow, sensitivity to crosslinking agents and decreased size. Taking advantage of the unique properties of the zebrafish model, I show that some of these symptoms stem from both decreased proliferation, as well as increased apoptosis of embryonic haematopoietic stem and progenitor cells. Co-mutation of p$L was able to rescue the haematopoietic defects seen in the single mutants, but led to tumour development, underscoring the role of rad51 as a tumour suppressor. I further demonstrate that prolonged inflammatory stress can exacerbate the haematological impairment, leading to an additional decrease in kidney marrow cell numbers. In contrast, prolonged aldehyde-derived stress did not induce symptoms in the mutant fish. These findings strengthen the assignment of RAD51 as a Fanconi gene and provide more evidence for the notion that aberrant p53 signalling during embryogenesis leads to the haematological defects seen later in life in FA. It also strengthens the evidence for the involvement of haematopoietic stress, such as inflammation, in the development of bone marrow failure. Further research on this novel zebrafish FA model will lead to a deeper understanding of the molecular basis of bone marrow failure in FA and the cellular role of RAD51.
77

Estudo do padrão facial em pacientes com anemia de Fanconi / Lúcia Fátima de Castro Ávila ; orientadora, Marina de Oliveira Ribas

Ávila, Lúcia Fátima de Castro January 2011 (has links)
Tese (doutorado) - Pontifícia Universidade Católica do Paraná, Curitiba, 2010 / Bibliografia: f. 41-44 / Anemia de Fanconi (AF) é uma doença genética autossômica recessiva, com falência da medula óssea, malformações congênitas ósseas: anomalias de crânio, face e membros superiores atraso do crescimento e associação a neoplasias. Este estudo avaliou o padrão / Fanconi Anemia (FA) is an autosomal recessive genetic disease, with bone marrow failure, congenital osseous anomalies such as skull, face and upper limb anomalies, growth delay and it presents association with neoplasia. This study evaluated craniofacial
78

Avaliação de fatores de risco na experiência de doença cárie em pacientes portadores de anemia de Fanconi / Lisiane Cândido ; orientadora, Marina de Oliveira Ribas

Cândido, Lisiane, 1979- January 2009 (has links)
Dissertação (mestrado) - Pontifícia Universidade Católica do Paraná, Curitiba, 2009 / Bibliografia: f. 20-22 / OBJETIVOS: Avaliar e correlacionar fatores de risco à doença cárie, como dieta, higienização bucal e microbiota bucal potencialmente cariogênica (Streptococcus mutans) com experiência de doença cárie por meio de levantamento de índice CPO-D/ ceo-d em paci / OBJECTIVES: This study was aimed to evaluate and to correlate risk factors for the caries disease with caries experiences by DMFT / dmft index in patients presenting with Fanconi´s anemia (FA). MATERIAL AND METHOD: 31 FA patients aged between 4 to 20 were
79

Análise da microbiota bucal de pacientes com anemia de fanconi submetidos ao transplante de células tronco hematopoéticas

Furquim, Camila Pinheiro January 2010 (has links)
Orientador: Prof. Dr. Cassius Carvalho Torres-Pereira / Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências da Saúde, Programa de Pós-Graduação em Odontologia. Defesa: Curitiba, 2016 / Inclui referências : f. 69-79 / Área de concentração / Resumo: A anemia de Fanconi (AF) é uma síndrome genética rara caracterizada por instabilidade cromossômica e dificuldade de reparo do DNA. Pacientes com AF desenvolvem o carcinoma de células escamosas (CCE) na boca mais cedo e com maior frequência que a população em geral, especialmente após o transplante de células tronco hematopoéticas (TCTH). Embora tenha aumentado a evidência de um papel etiológico da microbiota local e o processo de carcinogênese; não existem informações sobre a microbiota bucal de pacientes com AF. O objetivo desse estudo foi explorar a microbiota salivar de 61 pacientes com AF e comparar os resultados com a condição de saúde bucal e fatores de riscos associados ao desenvolvimento do CCE. Depois de responder a um questionário e ser submetido a um exame clínico intrabucal, todos os pacientes passaram por um etapa de coleta de saliva e as amostras foram analisadas utilizando o sequenciamento do gene 16S rRNA (Região Hipervariável :V3-V4 Miseq, Illumina). O perfil microbiano associado aos parâmetros clínicos e dados retirados de prontuário médico foram analisados utilizando modelos lineares. A mediana de idade da amostra estudada foi de 22 anos e a maioria deles haviam sido submetidos ao TCTH (n=53). Os filos bacterianos mais abundantes foram Firmicutes (média da abundância relativa ± desvio padrão(DP)) (42,1% ± 10,1%) e Bacteroidetes (25,4% ± 11,4%). O histórico de doença do enxerto contra o hospedeiro (DECH) bucal (n=27) estava associada com maiores proporções de Firmicutes (43,8% x 38,5%, p = 0,05) quando comparados com os que não apresentaram DECH. Altos níveis de sangramento gengival foram associados com os genêros Prevotella (22,25% x 20%), Streptococcus (19,83% x 17,61%), Porphyromonas (3,63% x 1,42%, p = 0,03), Treponema (1,02% x 0,28%, p = 0,009), Parvimonas (0,28% x 0,07%, p = 0,02) e Dialister (0,27% x 0,10%, p = 0,04). Por fim, pacientes transplantados à mais de 11 anos mostraram níveis mais elevados de Streptococcus (18,4%), Haemophilus (12,7%) e Neisseria (6,8%). Em conclusão, pacientes com AF que apresentavam piores condições de higiene bucal abrigavam maiores proporções de gêneros de bactérias compatíveis com doença periodontal. Foram observadas diferenças microbianas específicas, na presença de longo tempo de transplante, histórico de GVHD e mucosite, bem como, na presença de lesões com potencial de malignidade. Palavras-chave: Anemia de Fanconi. Câncer bucal. Microbiota. Saliva. Bactéria. Sequenciamento de Nucleotídeos de Alto Rendimento. / Abstract: Fanconi anemia (FA) is a rare genetic disease characterized by chromosomal instability and impaired DNA damage repair. FA patients develop oral squamous cell carcinoma (OSCC) earlier and more frequently than the general population, especially after hematopoeitic stem cell transplantation (HSCT). Although evidence of an etiological role of the local microbiome and carcinogenesis has grown, no information exists regarding the oral microbiome of FA patients. The aim of this study was to explore the salivary microbiome of 61 FA patients regarding their oral health status and OSCC risk factors. After answering a questionnaire and receiving oral clinical examination, saliva samples were collected and analyzed using 16rRNA sequencing (V3-V4 hypervariable region, MiSeq, Illumina). The microbial profiles associated with medical and clinical parameters were analyzed using general linear models. Patients were young (mean age = 22 yrs old) and most of them had received HSCT (n=53). The most abundant phyla were Firmicutes (mean relative abundance ± SD) (42.1%±10.1%) and Bacteroidetes (25.4%±11.4%). A history of graft-versus-host disease (GVHD) (n=27) was associated with higher proportions of Firmicutes (43.8% x 38.5%, p=0.05). High levels of gingival bleeding were associated with the genera Prevotella (22.25% x 20%), Streptococcus (19.83% x 17.61%), Porphyromonas (3.63% x 1.42%, p=0.03), Treponema (1.02% x 0.28%, p=0.009), Parvimonas (0.28% x 0.07%, p=0.02) and Dialister (0.27% x 0.10%, p=0.04). Finally, participants transplanted longer than 11 years showed highest levels of Streptococcus (18.4%), Haemophilus (12.7%) and Neisseria (6.8%). In conclusion, FA patients with poor oral hygiene harbored higher proportions of genera of bacteria compatible with gingival disease. Specific microbial differences were observed in the presence of a history of long time since HSCT, history of oral GVHD and mucositis as well when potential malignant oral lesion was present. Keywords: Fanconi anemia. Oral cancer. Microbiome. Saliva. Bacteria. Massively-Parallel Sequencing.
80

Análise de falha de pega em 2012 pacientes com anemia de Fanconi submetidos a transplante de células tronco hematopoiéticas no Hospital de Clínicas da Universidade Federal do Paraná

Sola, Caroline Bonamin dos Santos 28 May 2013 (has links)
Resumo: A Anemia de Fanconi (AF) é uma doença genética rara caracterizada por instabilidades cromossômicas que geram anormalidades somáticas de graus variáveis, falência medular progressiva e susceptibilidade aumentada a neoplasias. O único tratamento curativo é o transplante de células tronco hematopoéticas (TCTH), entretanto a toxicidade e falha de pega ainda são limitantes para sua realização. A falha de pega do enxerto ou rejeição é uma complicação grave e potencialmente fatal que ocorre em até 30% dos pacientes com AF submetidos ao TCTH, dependendo do tipo de doador e regime de condicionamento utilizado. Entre Janeiro de 1985 e Outubro de 2011, 238 pacientes com AF realizaram TCTH nessa instituição. Duzentos e doze pacientes foram avaliáveis quanto à pega medular e divididos em 3 grupos. O grupo 1 foi constituído por 25 pacientes que tiveram falha primária de pega (FPP). O grupo 2 por 9 pacientes com falha secundária de pega (FSP) ou evolução para leucemia e o grupo 3, com 178 casos com pega medular adequada. Os pacientes com falha primária e secundária de pega apresentaram maior duração de doença e maior número de transfusões sanguíneas prévias ao TCTH do que o grupo com pega medular (p=0,001 e p<0,001). Doador não aparentado (NAP) foi utilizado em 84% dos pacientes do G1 e apenas 33% do G3 (p<0,001); houve ainda menor número de transplantes totalmente compatíveis no G1 do que nos outros grupos (p<0,001). A fonte de células foi sangue de cordão umbilical (SCU) em 56% dos pacientes do G1 e 13% no G3. Na análise multivariada os fatores associadas a uma maior FPP foram maior número de transfusões (p=0,003), a utilização de doadores NAP (p=0,001) ou com incompatibilidades HLA (p=0,025) ou a ausência de fludarabina no regime de condicionamento (p=0,005). O fator predisponente para pega medular não sustentada ou evolução para leucemia foi maior número de transfusões (p=0,032). Vinte e quatro pacientes foram submetidos a um novo TCTH, sendo 20 do G1 e 4 do G2 e apenas seis pacientes estão vivos. A incidência cumulativa para a falha de pega foi de 18,9%, sendo maior nos transplantes com doadores NAP (36,2%) e com SCU (40%). A falha de pega ou rejeição é uma complicação extremamente grave e mais frequente nos transplantes não aparentados, com incompatibilidades e em pacientes mais transfundidos. Novos regimes de condicionamento, imunomodulação ou redução do tempo para o encontro de doadores NAP podem ser alternativas na tentativa de reduzir a incidência da rejeição nos pacientes com AF.

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