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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

Caracterização do fenótipo ósseo do modelo mgΔloxPneo da síndrome de Marfan e análise dos mecanismos de patogênese / Characterization of the skeletal phenotype of the mg?loxPneo mouse model of Marfan syndrome and analysis of the mechanisms of pathogenesis

Kawahara, Elisa Ito 02 December 2016 (has links)
A Síndrome de Marfan (SMF) é uma doença de caráter autossômico dominante que acomete o tecido conjuntivo. As principais manifestações clínicas afetam o sistema cardiovascular, ótico e ósseo. A SMF é causada por mutações no gene FBN1, que codifica a proteína extracelular fibrilina-1, componente principal das microfibrilas, que formam as fibras elásticas. Estudos mostraram que mutações no gene da fibrilina-1 levam a um aumento indiscriminado do TGF-Β ativo na matriz, que resulta nos principais fenótipos da doença. O Sistema Renina Angiotensina (RAS) tem como produto principal a Angiotensina II (Ang-II), envolvida na regulação da massa óssea e da atividade do TGF-Β. Estratégias terapêuticas para a SMF utilizando fármacos que agem no RAS têm sido alvos de estudos em modelos animais. Em camundongos, Ramipril, inibidor da ACE (Angiotensin-converting enzyme inhibitor, ACEi), aumenta a transcrição do gene Fbn1 em 35% e melhora a cifose, característica do fenótipo ósseo no modelo animal mgΔloxPneo. O mecanismo de ação do Ramipril no sistema ósseo ainda não está totalmente elucidado, sendo que pode agir por diminuição na produção de Ang-II e consequente diminuição nos níveis de TGF-Β, ou pela inibição de degradação da bradicinina (BK) pela Ang-II. A bradicinina ativa diretamente seu receptor B2R, que induz ações fisiológicas opostas às da Ang-II. O objetivo deste trabalho foi avaliar e compreender os mecanismos gerais da patogênese óssea do modelo murino mgΔloxPneo para a SMF. Para tanto, foi analisado o fenótipo ósseo dos animais mgΔloxPneo e selvagens controle e tratados com Ramipril. Foi verificado que, além da cifose, os animais mutantes apresentaram pior estrutura óssea. O tratamento melhorou a cifose, porém não alterou a qualidade óssea dos animais mutantes. Portanto, o efeito benéfico do Ramipril na cifose dos animais mgΔloxPneo não se deve a uma melhora da estrutura óssea, e pode estar relacionado à integridade do ligamento que sustenta a coluna vertebral. Com o intuito de testar a hipótese de que a sinalização pelo receptor B2R da BK possa estar envolvida no desenvolvimento do fenótipo ósseo dos animais mgΔloxPneo, foram gerados animais mgΔloxPneo e knockout para o receptor B2R. Os resultados mostram que o receptor B2R não interfere no desenvolvimento da cifose, sendo apenas o genótipo para Fbn1 o fator determinante para a manifestação desse fenótipo. Foi realizada a análise de RNA-seq para verificar genes e vias diferencialmente expressas que possam explicar o mecanismo de desenvolvimento do fenótipo ósseo dos animais mgΔloxPneo. Foram encontradas vias como da adesão focal, interação receptor-meio extracelular (MEC), junção ocludente, reparação por excisão de nucleotídeo e de reparação missmatch, que podem explicar alterações no metabolismo de células ósseas. Além disso, foram encontradas diferenças de expressão de genes relacionados ao metabolismo muscular esquelético, o que está de acordo com a hipótese de regulação parácrina entre o tecido muscular e ósseo, levando a uma pior estrutura óssea / Marfan syndrome (MFS) is an autosomal dominant disease that affects the connective tissue. The main clinical manifestations affect the cardiovascular, optical and bone systems. MFS is caused by mutations in the FBN1 gene, that encodes the extracellular protein fibrillin-1, a major component of microfibrils, which form elastic fibers. Studies have shown that mutations in the fibrillin-1 gene lead to an indiscriminate increase in active TGF-Β in the matrix, which results in the major phenotypes of the disease. The Renin Angiotensin System (RAS) has as its main product Angiotensin II (Ang-II), involved in bone mass regulation and TGF-Β activity. Therapeutic strategies using drugs targeting the RAS have been studied in animal models. Ramipril, an ACE inhibitor (Angiotensin-converting enzyme inhibitor, ACEi), increase Fbn1 gene expression in 35% and improve kyphosis index in the mgΔloxPneo mouse model for SMF. Its mechanism of action in bone tissue is not completely elucidated, and it may act by decreasing Ang-II production and consequent reduction in TGF-Β levels, or by inhibiting degradation of bradykinin (BK) by Ang II. BK directly activates its B2R receptor, which induces opposite physiological actions to Ang-II. This study aims to evaluate and understand the general mechanisms of bone pathogenesis in the mgΔloxPneo mouse model. We analyzed the bone phenotype of mgΔloxPneo and wildtype animals treated, or not, with Ramipril by measuring the kyphosis index (KI), micro computed tomography (μCT) and Real-time PCR (RT-PCR). We found that mutant animals showed a greater degree of kyphosis and an altered bone structure. Ramipril improved kyphosis but did not alter bone quality of mutant animals, while in wild type animals Ramipril decreased bone structure without altering KI. Therefore, the beneficial effect of Ramipril on mgΔloxPneo animals\' kyphosis is not due to an improvement in bone structure. In order to test the hypothesis where signaling through BK B2R receptor may be involved in the development of bone phenotype of mgΔloxPneo animals, a mouse model with the mgΔloxPneo mutation and knockout for B2R receptor was generated. The analysis of these animals show that the B2R receptor does not interfere with the development of kyphosis, with Fbn1 genotype as sole determinant for this phenotype manifestation. RNA-seq analysis was performed to verify differential expression of genes and altered cellular pathways, which could reveal mechanisms of bone phenotype development in mgΔloxPneo animals. Altered pathways found included focal adhesion, receptor- extracellular matrix (ECM) interaction, tight junction, nucleotide excision repair and missmatch repair, which may explain changes in bone cells metabolism. In addition, there were differences in gene expression related to skeletal muscle metabolism, which is in agreement with the paracrine regulation of bone and muscle tissue, leading to worst bone structure
2

Caracterização do fenótipo ósseo do modelo mgΔloxPneo da síndrome de Marfan e análise dos mecanismos de patogênese / Characterization of the skeletal phenotype of the mg?loxPneo mouse model of Marfan syndrome and analysis of the mechanisms of pathogenesis

Elisa Ito Kawahara 02 December 2016 (has links)
A Síndrome de Marfan (SMF) é uma doença de caráter autossômico dominante que acomete o tecido conjuntivo. As principais manifestações clínicas afetam o sistema cardiovascular, ótico e ósseo. A SMF é causada por mutações no gene FBN1, que codifica a proteína extracelular fibrilina-1, componente principal das microfibrilas, que formam as fibras elásticas. Estudos mostraram que mutações no gene da fibrilina-1 levam a um aumento indiscriminado do TGF-Β ativo na matriz, que resulta nos principais fenótipos da doença. O Sistema Renina Angiotensina (RAS) tem como produto principal a Angiotensina II (Ang-II), envolvida na regulação da massa óssea e da atividade do TGF-Β. Estratégias terapêuticas para a SMF utilizando fármacos que agem no RAS têm sido alvos de estudos em modelos animais. Em camundongos, Ramipril, inibidor da ACE (Angiotensin-converting enzyme inhibitor, ACEi), aumenta a transcrição do gene Fbn1 em 35% e melhora a cifose, característica do fenótipo ósseo no modelo animal mgΔloxPneo. O mecanismo de ação do Ramipril no sistema ósseo ainda não está totalmente elucidado, sendo que pode agir por diminuição na produção de Ang-II e consequente diminuição nos níveis de TGF-Β, ou pela inibição de degradação da bradicinina (BK) pela Ang-II. A bradicinina ativa diretamente seu receptor B2R, que induz ações fisiológicas opostas às da Ang-II. O objetivo deste trabalho foi avaliar e compreender os mecanismos gerais da patogênese óssea do modelo murino mgΔloxPneo para a SMF. Para tanto, foi analisado o fenótipo ósseo dos animais mgΔloxPneo e selvagens controle e tratados com Ramipril. Foi verificado que, além da cifose, os animais mutantes apresentaram pior estrutura óssea. O tratamento melhorou a cifose, porém não alterou a qualidade óssea dos animais mutantes. Portanto, o efeito benéfico do Ramipril na cifose dos animais mgΔloxPneo não se deve a uma melhora da estrutura óssea, e pode estar relacionado à integridade do ligamento que sustenta a coluna vertebral. Com o intuito de testar a hipótese de que a sinalização pelo receptor B2R da BK possa estar envolvida no desenvolvimento do fenótipo ósseo dos animais mgΔloxPneo, foram gerados animais mgΔloxPneo e knockout para o receptor B2R. Os resultados mostram que o receptor B2R não interfere no desenvolvimento da cifose, sendo apenas o genótipo para Fbn1 o fator determinante para a manifestação desse fenótipo. Foi realizada a análise de RNA-seq para verificar genes e vias diferencialmente expressas que possam explicar o mecanismo de desenvolvimento do fenótipo ósseo dos animais mgΔloxPneo. Foram encontradas vias como da adesão focal, interação receptor-meio extracelular (MEC), junção ocludente, reparação por excisão de nucleotídeo e de reparação missmatch, que podem explicar alterações no metabolismo de células ósseas. Além disso, foram encontradas diferenças de expressão de genes relacionados ao metabolismo muscular esquelético, o que está de acordo com a hipótese de regulação parácrina entre o tecido muscular e ósseo, levando a uma pior estrutura óssea / Marfan syndrome (MFS) is an autosomal dominant disease that affects the connective tissue. The main clinical manifestations affect the cardiovascular, optical and bone systems. MFS is caused by mutations in the FBN1 gene, that encodes the extracellular protein fibrillin-1, a major component of microfibrils, which form elastic fibers. Studies have shown that mutations in the fibrillin-1 gene lead to an indiscriminate increase in active TGF-Β in the matrix, which results in the major phenotypes of the disease. The Renin Angiotensin System (RAS) has as its main product Angiotensin II (Ang-II), involved in bone mass regulation and TGF-Β activity. Therapeutic strategies using drugs targeting the RAS have been studied in animal models. Ramipril, an ACE inhibitor (Angiotensin-converting enzyme inhibitor, ACEi), increase Fbn1 gene expression in 35% and improve kyphosis index in the mgΔloxPneo mouse model for SMF. Its mechanism of action in bone tissue is not completely elucidated, and it may act by decreasing Ang-II production and consequent reduction in TGF-Β levels, or by inhibiting degradation of bradykinin (BK) by Ang II. BK directly activates its B2R receptor, which induces opposite physiological actions to Ang-II. This study aims to evaluate and understand the general mechanisms of bone pathogenesis in the mgΔloxPneo mouse model. We analyzed the bone phenotype of mgΔloxPneo and wildtype animals treated, or not, with Ramipril by measuring the kyphosis index (KI), micro computed tomography (μCT) and Real-time PCR (RT-PCR). We found that mutant animals showed a greater degree of kyphosis and an altered bone structure. Ramipril improved kyphosis but did not alter bone quality of mutant animals, while in wild type animals Ramipril decreased bone structure without altering KI. Therefore, the beneficial effect of Ramipril on mgΔloxPneo animals\' kyphosis is not due to an improvement in bone structure. In order to test the hypothesis where signaling through BK B2R receptor may be involved in the development of bone phenotype of mgΔloxPneo animals, a mouse model with the mgΔloxPneo mutation and knockout for B2R receptor was generated. The analysis of these animals show that the B2R receptor does not interfere with the development of kyphosis, with Fbn1 genotype as sole determinant for this phenotype manifestation. RNA-seq analysis was performed to verify differential expression of genes and altered cellular pathways, which could reveal mechanisms of bone phenotype development in mgΔloxPneo animals. Altered pathways found included focal adhesion, receptor- extracellular matrix (ECM) interaction, tight junction, nucleotide excision repair and missmatch repair, which may explain changes in bone cells metabolism. In addition, there were differences in gene expression related to skeletal muscle metabolism, which is in agreement with the paracrine regulation of bone and muscle tissue, leading to worst bone structure
3

Appropriateness of Repeated Clinical Alerts to Add Angiotensin Converting Enzyme Inhibitor Therapy in Diabetic Patients with Medicare Part D Coverage

Hryshko, Patrick, Johnson, Zac, Scovis, Nicki January 2014 (has links)
Class of 2014 Abstract / Specific Aims: To identify reasons that an angiotensin converting enzyme inhibitor (ACEi) would not be indicated in diabetic patients with repeated clinical alerts to add ACEi therapy for preservation of renal function and/or hypertension. In addition, to identify if these repeated clinical alerts to add ACEi therapy are appropriate. Methods: Eligible patient charts were reviewed by researchers using a data dictionary to complete a standardized spreadsheet with patient demographic information (age, gender, and location), type of diabetes mellitus, evidence indicative of comorbid hypertension, action taken by pharmacist in response to clinical alert (letter sent to patient and letter sent to prescriber), and rationale of that action. This data, along with SOAP notes of patient interactions, was used by researchers to classify the repeated clinical alert as appropriate or inappropriate. Main Results: There were a total of 200 charts reviewed (male n = 61 (30.5%), female n = 139 (69.5%), mean age = 70 ± 11 years). Reasons for not contacting patients again include previous failure or adverse drug reaction (n = 62, 31.0%), patient did not meet call script requirements (n = 55, 27.5%), patient did not have diabetes or hypertension (n = 20, 10.0%), potential drug-disease interaction (n = 17, 8.5%), overlapping or previously addressed alerts (1.9%), or documentation was provided for “other” reasons (n = 43, 21.5%). The previous failure or adverse drug reaction rationale was appropriate in 32 of 62 repeated clinical alerts (52%; χ2= 10.15). The patient did not have diabetes or hypertension rationale was appropriate in 11 of 20 repeated clinical alerts (55%, χ2= 2.72). The potential drug-disease interaction rationale was appropriate in 3 of 17 repeated clinical alerts (8%, χ2= 9.89). The patient did not meet call script requirements rationale was appropriate in 31 of 55 repeated clinical alerts (56%, χ2= 6.91). The overlapping or previous alerts rationale was appropriate in 2 of 3 repeated clinical alerts (67%, χ2= 0.18). The “other” rationale were appropriate in 22 of 43 repeated clinical alerts (51%, χ2= 7.21) Overall, retrigger alerts were considered appropriate 50.5% of the time compared to the predicted value of 90% (χ2= 347 > critical value = 3.84 for p = 0.05 Conclusion: There are multiple reasons pharmacists do not recommend initiating ACEi therapy in patients with diabetes. Although the Medication Management Center (MMC) has rationale of these reasons documented after individual patient interactions, there are still several reasons why a retrigger alert would be appropriate despite that rationale. In addition, retrigger alerts were not considered appropriate as frequently as expected.

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