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Padronização das técnicas de PNA e PCR em tempo real para detecção das mutações ativadoras no GNAS na síndrome de McCune-Albright / Standardization of the PNA and real time techniques for the detection of activating mutations in the GNAS in McCune-Albright syndromeMariani, Beatriz Marinho de Paula 05 October 2012 (has links)
A síndrome de McCune Albrigth (SMA) é uma doença genética não hereditária, com incidência estimada entre 1/100.000 e 1/1.000.000 casos/ano. A SMA caracteriza-se clinicamente pela tríade: displasia óssea fibrosa (FD), manchas cutâneas café-com-leite e hiperfunção endócrina tais como: síndrome de Cushing, pseudo-puberdade precoce, hipertiroidismo, acromegalia. O diagnóstico da SMA clássica é usualmente baseado no quadro clínico associado a dosagens hormonais e exames de imagem, principalmente cintilografia do esqueleto. No entanto, quadros atípicos e formas parciais muitas vezes dificultam o diagnóstico preciso da síndrome. O objetivo deste estudo foi padronizar dentre as técnicas de PNA (peptide nucleic acid) e PCT em Tempo Real, para a detecção de polimorfismos de base única (SNPs), a técnica mais sensível para a discriminação das mutações ativadoras da subunidade da proteína G. Para este estudo foram selecionados 32 pacientes, 1 masculino e 31 femininos, com SMA, todos em seguimento no Hospital das Clínicas da Faculdade de Medicina da USP. Como resultado positivo, apresentamos nesse trabalho pela primeira vez o uso do RT-PCR genotipagem na detecção das mutações ativadoras da proteína G, em DNA extraído de tecidos afetados e em leucócitos de sangue periférico, sendo a técnica considerada sensível o suficiente para discriminar de forma simples e rápida as mutações ativadoras da PGs. Sugerimos nesse estudo o uso da técnica de discriminação alélica pelo sistema Taqman. Essa técnica possibilita a detecção destas mutações gsp no sangue periférico mesmo numa baixa porcentagem, uma vez que nem sempre o tecido afetado (gônada, osso, hipófise) é disponível. / The McCune-Albright Syndrome (MAS) is a genetic disease, with incidence estimated at 1/100.000 and 1/1000000 cases per year. MAS is clinically characterized by the triad: bone fibrous dysplasia (FD) café-au-lait skin spots and endocrine hyperfunction, such as: precocious puberty (PP), Cushing's syndrome, hyperthyroidism and acromegaly. The diagnosis of MAS is originally based on clinical characteristics associated with hormonal and imaging studies. However, atypical and partial forms often hamper the accurate diagnosis of the syndrome. For this study we selected 32 patients, 1male and 31 females, all being treated in Hospital das Clínicas, School of Medicine, University of São Paulo. As a positive result, we showed for the first time the use of Real Time PCR/genotyping for the detection of activating mutations of the stimulatory G protein, using blood leucocytes DNA. This technique was sensible and can bring fast results for the patient and the physician, making the diagnosis easier. Our study proposes the use of allelic discrimination by Taqman system, which can be used as a probe that allows the identification of specific genotypes. These techniques could help detect these mutations in peripheral blood when the affected tissue is not available.
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Padronização das técnicas de PNA e PCR em tempo real para detecção das mutações ativadoras no GNAS na síndrome de McCune-Albright / Standardization of the PNA and real time techniques for the detection of activating mutations in the GNAS in McCune-Albright syndromeBeatriz Marinho de Paula Mariani 05 October 2012 (has links)
A síndrome de McCune Albrigth (SMA) é uma doença genética não hereditária, com incidência estimada entre 1/100.000 e 1/1.000.000 casos/ano. A SMA caracteriza-se clinicamente pela tríade: displasia óssea fibrosa (FD), manchas cutâneas café-com-leite e hiperfunção endócrina tais como: síndrome de Cushing, pseudo-puberdade precoce, hipertiroidismo, acromegalia. O diagnóstico da SMA clássica é usualmente baseado no quadro clínico associado a dosagens hormonais e exames de imagem, principalmente cintilografia do esqueleto. No entanto, quadros atípicos e formas parciais muitas vezes dificultam o diagnóstico preciso da síndrome. O objetivo deste estudo foi padronizar dentre as técnicas de PNA (peptide nucleic acid) e PCT em Tempo Real, para a detecção de polimorfismos de base única (SNPs), a técnica mais sensível para a discriminação das mutações ativadoras da subunidade da proteína G. Para este estudo foram selecionados 32 pacientes, 1 masculino e 31 femininos, com SMA, todos em seguimento no Hospital das Clínicas da Faculdade de Medicina da USP. Como resultado positivo, apresentamos nesse trabalho pela primeira vez o uso do RT-PCR genotipagem na detecção das mutações ativadoras da proteína G, em DNA extraído de tecidos afetados e em leucócitos de sangue periférico, sendo a técnica considerada sensível o suficiente para discriminar de forma simples e rápida as mutações ativadoras da PGs. Sugerimos nesse estudo o uso da técnica de discriminação alélica pelo sistema Taqman. Essa técnica possibilita a detecção destas mutações gsp no sangue periférico mesmo numa baixa porcentagem, uma vez que nem sempre o tecido afetado (gônada, osso, hipófise) é disponível. / The McCune-Albright Syndrome (MAS) is a genetic disease, with incidence estimated at 1/100.000 and 1/1000000 cases per year. MAS is clinically characterized by the triad: bone fibrous dysplasia (FD) café-au-lait skin spots and endocrine hyperfunction, such as: precocious puberty (PP), Cushing's syndrome, hyperthyroidism and acromegaly. The diagnosis of MAS is originally based on clinical characteristics associated with hormonal and imaging studies. However, atypical and partial forms often hamper the accurate diagnosis of the syndrome. For this study we selected 32 patients, 1male and 31 females, all being treated in Hospital das Clínicas, School of Medicine, University of São Paulo. As a positive result, we showed for the first time the use of Real Time PCR/genotyping for the detection of activating mutations of the stimulatory G protein, using blood leucocytes DNA. This technique was sensible and can bring fast results for the patient and the physician, making the diagnosis easier. Our study proposes the use of allelic discrimination by Taqman system, which can be used as a probe that allows the identification of specific genotypes. These techniques could help detect these mutations in peripheral blood when the affected tissue is not available.
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Characterization of Putative Mammalian Adenylyl Cyclase Inhibitors Using the Fission Yeast Schizosaccharomyces pombePacella, Daniel January 2022 (has links)
Thesis advisor: Charles Hoffman / In both mammals and fission yeast, control of cAMP levels is maintained by adenylyl cyclases (ACs), which synthesize cyclic nucleotide, and by cyclic nucleotide phosphodiesterases (PDEs), which are responsible for its degradation. AC activity is regulated by G proteins, which respond to signals from G protein-coupled receptors (GPCRs) that detect extracellular signaling factors such as hormones. cAMP is a second messenger that has several effectors, with protein kinase A (PKA) being a primary target of activation that phosphorylates several downstream targets and results in modulation of pathways such as cell growth and gluconeogenesis. Aberrant cAMP regulation has been linked to several human disease states, such as McCune-Albright Syndrome, which is the result of elevated cAMP levels. Whereas the targeting of PDEs with drugs and selective inhibitors has been very successful, the AC-inhibiting compounds identified to date are unfavorable for clinical use. Inhibitors may not necessarily bind to and inhibit a given AC directly but instead act on a regulatory pathway such as calmodulin signaling. Theoretically, they also may bind to the G protein, interfere with the AC-G protein stimulatory complex, or regulate a factor of AC transcription. Since more than one AC species is expressed in many human cell types, it is difficult to selectively reduce cAMP levels. Therefore, for an AC inhibitor to be favored as a candidate for drug development, it is likely that the compound should directly bind to and inhibit the AC. This thesis describes my studies on a scaffold of 41 structurally related BCAC compounds, called the BCAC51 scaffold, that was identified in a high-throughput screen (HTS) with Schizosaccharomyces pombe strains transformed with GNAS and either mammalian AC4 or AC7. I carried out a series of experiments to examine whether the compounds bind to and inhibit mammalian ACs directly. The most active compounds were further characterized for potency and specificity against a panel of ACs. Several compounds significantly reduced cAMP production, but it could not be determined if the compounds directly or indirectly altered AC activity. I also cloned and constructed strains expressing the human wild-type AC5 gene and the AC5 R418W mutant, which has shown an increased sensitivity to GNAS. cAMP assays on these strains using various BCAC compounds showed that while most compounds had similar effects on both forms of AC5, BCAC62 was significantly more effective on the wild-type enzyme than on the mutant AC5, although the reason for this is unclear. To test whether the compounds could reduce AC activity in the absence of GNAS (basal activity), a flow cytometry study was carried out using a PKA-repressed GFP reporter. Results suggested that BCAC compounds do reduce basal-AC activity and therefore do not act by binding to and inhibiting GNAS, by interfering with the AC-GNAS stimulatory complex, nor by stimulating PDE. Finally, I developed a molecular genetic screen for mutant alleles of an AC gene that confer compound-resistance. One cycle of the screen is near completion, and the screen provides a foundation for future examination of compound-resistant AC candidates. The results presented in this thesis serve as a basis for further research into members of the BCAC51 compound series being putative direct inhibitors of mammalian ACs. / Thesis (BS) — Boston College, 2022. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Scholar of the College. / Discipline: Biology.
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Etiologies héréditaires et somatiques des adénomes hypophysaires : étude du gène Men1 et du locus Gnas / Hereditary and somatic etiologies of pituitary adenomas : study of the Men1 gene and the Gnas locusRomanet, Pauline 09 July 2018 (has links)
La Néoplasie Endocrinienne Multiple de type 1 (NEM1) est une maladie génétique qui associe hyperparathyroïdie primaire, tumeurs neuroendocrines digestives et adénomes hypophysaires. Elle est due à des mutations non récurrentes du gène MEN1, parfois difficile à classer. Nous avons rassemblé et analysé les données cliniques et génétiques de 1676 patients français porteurs d’une variation de MEN1 des 4 laboratoires experts du groupe TENGEN. De ce travail, nous avons alimenté une base de données de variants (UMD MEN1) et établir le profil mutationnel de MEN1 en France. Dans une seconde partie, nous avons établi des recommandations pour la classification des variants faux sens de MEN1 en adaptant les Guidelines de l’ACMG-AMP (American College of Medical Genetics).Le Syndrome de McCune-Albright (SMA) est du à des mutations postzygotiques activatrices récurrentes du gène GNAS, responsables d’un mosaïcisme somatique, souvent indétectables dans le sang. En utilisant une technique de PCR quantitative ultrasensible, le taux de détection des mutations R201C et R201H est de 50% dans le sang de 16 patients présentant 1 à 3 lésions majeures du SMA. Pour la 1ere fois, nous avons retrouvé ces mutations dans l’ADN circulant de 3/4 patients testés.Ces mutations sont retrouvées aussi dans 30 à 40% des adénomes somatotropes. Le locus GNAS est soumis à empreinte parentale, responsable d’une expression mono-allélique de GNAS dans certains tissus comme l’hypophyse. Dans une série de 57 adénomes somatotropes nous avons montré une perturbation de l’empreinte de GNAS, associée à une relâche de l’empreinte mais n’entraînait pas d’augmentation de l’expression du gène GNAS. / The Multiple Endocrine Neoplasia 1 (MEN1) is due to MEN1 mutations and characterized by a broad spectrum of lesions including hyperparathyroidism, pituitary adenomas and neuroendocrine tumors. Missense variants are frequent and could lead wrong interpretation. We collected and analyzed all the 370 variants of 1676 patients sequenced for ten years by the TENGEN network (French oncogenetics of neuroendocrine tumors). We registered them in the UMD MEN1 database. Then, consensus was reached to validate adjustments to the ACMG-AMP guidelines for MEN1 locus-specific interpretation of missense variants. The McCune-Albright syndrome (MAS) is a rare pediatric mosaic genetic disorder. MAS results from recurrent post-zygotic GNAS mutations, not detectable in blood DNA by Sanger. We develop an ultrasensitive quantitative PCR using digital droplet PCR™ (ddPCR™) in order to target the R201C and R201H GNAS mutations. After a validation study, we clinically evaluated ddPCR™ in the whole blood DNA or circulating cell-free DNA (ccfDNA) of patients presented with at least 1 MAS lesion. First we detected in ccfDNA the mosaic somatic GNAS mutant. The ddPCR™ showed a mutation detection rate of 50% in blood DNA of the 16 included patients and 3/4 in ccfDNA.GNAS mutations are also reported in 30 to 40% of somatotroph tumors. GNAS is encoded by an imprinted locus, responsible for a mono-allelic expression in pituitary. We explored the GNAS locus methylation status of 57 somatotroph adenomas and showed disturbance. We studied the impact on GNAS, SST2R and AIP expression of this disturbance. We showed an imprinting relaxation not associated with an increased expression of GNAS.
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Zur Klinik und Genetik von Skelettdysplasien mit Modellierungsstörungen, Hyperostose und SkleroseTinschert, Sigrid 08 March 2004 (has links)
Die Homöostase des Knochengewebes wird durch das balancierte Zusammenspiel von Ossifikation und Resorption gewährleistet. Eine in Relation zur Resorption zu starke Ossifikation führt zur Modellierungsstörung, Hyperostose und Sklerose. Knochenerkrankungen mit diesen Merkmalen werden als Sklerosierende Skelettdysplasien erfasst. Gegenstand der vorliegenden Arbeit sind fünf Skelettdysplasien aus dem Formenkreis der Sklerosierenden Skelettdysplasien: (1) Craniometaphysäre Dysplasie, autosomal dominante Form (MIM #123000); (2) Metaphysäre Dysplasie, Typ Braun-Tinschert (MIM *605946); (3) Caffey-Syndrom (MIM *114000); (4) McCune-Albright-Syndrom (MIM #174800); (5) Melorheostose (MIM 155950). Diese werden auf unterschiedlichen pathogenetischen Ebenen charakterisiert, die den Etappen des Weges entsprechen, der mit der Analyse des Phänotyps beginnt und zu einer Aufklärung des Basisdefektes führt. Die Arbeit gliedert sich ein in die Reihe von Bemühungen, zum molekularen Verständnis von Erkrankungen des Skelettsystems beizutragen. / Homeostasis of bone tissue is maintained by the balanced process of bone formation and resorption. Increased ossification in relation to resorption gives rise to conditions with modelling defects, hyperostosis and sclerosis. Skeletal diseases with these signs are classified as sclerosing bone dysplasias. The work presented here focuses on five skeletal dysplasias from the group of sclerosing bone dysplasias: (1) Craniometaphyseal dysplasia, autosomal dominant form (MIM #123000); (2) Metaphyseal dysplasia, Braun-Tinschert type (MIM *605946); (3) Caffey syndrome (MIM *114000); (4) McCune-Albright syndrome (MIM #174800); (5) Melorheostosis (MIM 155950). They were investigated at different pathogenetic levels that represent different steps on the path from phenotypic characterisation to clarification of the respective basic molecular defect. This work has contributed to our understanding of the molecular basis of skeletal diseases.
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