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Expressão do gene da tirosina quinase de Bruton e de sensores do estresse do retículo endoplasmático na agamaglobulinemia ligada ao X = Expression of Bruton's tyrosine kinase gene and endoplasmic reticulum stress sensors in X-linked agammaglobulinemia / Expression of Bruton's tyrosine kinase gene and endoplasmic reticulum stress sensors in X-linked agammaglobulinemiaRamalho, Vanessa Domingues, 1985- 24 August 2018 (has links)
Orientador: Maria Marluce dos Santos Vilela / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-24T17:02:47Z (GMT). No. of bitstreams: 1
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Previous issue date: 2014 / Resumo: A agamaglobulinemia ligada ao X (XLA; OMIM#300755) é caracterizada por um bloqueio na diferenciação dos linfócitos B na medula óssea, levando à profunda hipogamaglobulinemia e reduzido número ou ausência de linfócitos B periféricos. Os pacientes são susceptíveis a infecções recorrentes por bactérias encapsuladas e enterovírus. XLA é causada por mutações no gene da tirosina quinase de Bruton (BTK). Contudo, não há estudos de relação entre expressão protéica e o tipo de mutação, nem sobre as conseqüências da retenção intracelular do excesso de proteínas mal formadas. Os objetivos deste trabalho foram avaliar a expressão de BTK e sua relação com o tipo de mutação em pacientes com XLA, assim como verificar suas conseqüências nos sensores de estresse do retículo endoplasmático. O diagnóstico de XLA foi baseado em infecções recorrentes, níveis significativamente reduzidos de IgM, IgG e IgA, linfócitos B circulantes <2% e mutação identificada no gene BTK. A expressão dos transcritos de BTK foi avaliada por PCR quantitativo em tempo real em oito pacientes XLA e oito controles. Pela mesma técnica, foi avaliada a expressão de 10 genes do estresse do retículo endoplasmático em seis pacientes e seis controles. Foram caracterizadas quatro mutações missense, uma mutação nonsense, dois frameshifts e um defeito em sítio de splicing. As mutações do tipo nonsense, frameshift e defeito em sítio de splicing levaram à formação de stop codon prematuro. Foi detectado um perfil de expressão de BTK diferenciado nos pacientes com mutações com stop codon prematuro em comparação aos pacientes com mutações missense e controles saudáveis. Especificamente, os pacientes com mutações com stop codon prematuro apresentaram redução da expressão de BTK (P = 0,004). No entanto, verificamos que as mutações missense não afetaram a expressão de BTK. Por meio de imunocitoquímica, encontramos que as mutações com stop codon prematuro levaram à deficiência da expressão da proteína BTK e as do tipo missense resultaram na localização anormal da proteína no citoplasma celular, o que evidencia a síntese de proteína não funcional. Os pacientes com XLA apresentaram expressão aumentada do marcador de estresse do retículo endoplasmático XBP1 (P = 0,002). Em conclusão, a quantificação da expressão de mRNA para BTK é uma ferramenta para diferenciar as conseqüências mutacionais em pacientes com XLA. Ela também pode contribuir para o estudo de transcritos em outras doenças genéticas com diferentes tipos de mutação. Este é o primeiro relato de estresse do retículo endoplasmático na agamaglobulinemia ligada ao X / Abstract: X-linked agammaglobulinemia (XLA, OMIM # 300755) is characterized by a block in differentiation of B lymphocytes in the bone marrow, leading to profound hypogammaglobulinemia and few or no peripheral B lymphocytes. Patients are susceptible to recurrent infections by encapsulated bacteria and enteroviruses. XLA is caused by mutations in the Bruton tyrosine kinase gene (BTK). However, there have been no studies on the relationship between protein expression and the type of mutation, nor on the consequences of the disruption of protein folding that results in intracellular retention. The objectives of this study were to evaluate BTK expression and its mutation type in patients with XLA, as well as to verify their consequences on the endoplasmic reticulum stress sensors. The XLA diagnosis was based on recurrent infections, significantly reduced levels of IgM, IgG and IgA, circulating B lymphocytes <2% and BTK gene mutation identified. The expression of BTK transcripts was assessed by quantitative real-time PCR in eight XLA patients and eight control subjects. By the same technique, the expression of 10 endoplasmic reticulum stress genes was measured in six patients and six controls. Four missense mutations, one nonsense mutation, two frameshifts and a splice site defect were characterized. Mutations of the nonsense type, frameshift and splice site defect led to a premature stop codon formation. A differential profile of expression of BTK was detected in patients with mutations that led to a premature stop codon compared to patients with missense mutations and healthy controls. Specifically, patients with mutations resulting in a premature stop codon exhibited reduced expression of BTK gene (P = 0.004). However, it was found that missense mutations did not affect BTK expression. By immunocytochemistry, we found that mutations with a premature stop codon impaired expression of BTK protein and that missense mutations led to an abnormal localization of the protein in the cell cytoplasm, showing the synthesis of a non-functional protein. Patients with XLA showed increased expression of the endoplasmic reticulum stress marker XBP1 (P = 0.002). In conclusion, the quantification of mRNA expression for BTK is a tool to differentiate mutational consequences in patients with XLA. It can also contribute to the study of transcripts in other genetic diseases with different types of mutation. This is the first report on endoplasmic reticulum stress in X-linked agammaglobulinemia / Doutorado / Saude da Criança e do Adolescente / Doutora em Ciências
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Mitochondrial DNA mutations in hepatocellular carcinoma (HCC) of Chinese patients.January 2004 (has links)
Fu Zhenming. / Thesis submitted in: December 2003. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 138-162). / Abstracts in English and Chinese. / List of abbreviations --- p.i / Abstract (in English) --- p.ii / 摘要(中文) --- p.iii / Acknowledgement --- p.iv / Chapter Chapter 1. --- Introduction and Objectives of Study --- p.1 / Chapter 1.1 --- Hepatocellular carcinoma in general --- p.2 / Chapter 1.1.1 --- "Epidemiology, risk factors" --- p.2 / Chapter 1.1.2 --- Pathology and staging --- p.4 / Chapter 1.1.3 --- Treatment --- p.6 / Chapter 1.1.4 --- Improvement of early detection and treatment of HCC --- p.7 / Chapter 1.2 --- General aspects of mitochondria and mitochondrial DNA (mtDNA) --- p.10 / Chapter 1.2.1 --- Structure and dynamics of mitochondria --- p.10 / Chapter 1.2.1.1 --- General introduction of mitochondria --- p.10 / Chapter 1.2.1.2 --- Respiration chain of mitochondria --- p.11 / Chapter 1.2.2 --- The mitochondrial genome --- p.14 / Chapter 1.2.2.1 --- Strucure --- p.14 / Chapter 1.2.2.2 --- Genes for structure proteins --- p.16 / Chapter 1.2.2.3 --- Genes for translation --- p.17 / Chapter 1.2.2.4 --- Imported proteins and RNAs --- p.17 / Chapter 1.2.3 --- Mitochondrial DNA maintenance --- p.19 / Chapter 1.2.4 --- Mitochondrial DNA replication --- p.25 / Chapter 1.2.5 --- Mitochondrial DNA transcription --- p.30 / Chapter 1.2.6 --- Mitochondrial DNA translation --- p.32 / Chapter 1.3 --- MtDNA diseases --- p.35 / Chapter 1.4 --- MtDNA mutation and HCC --- p.35 / Chapter 1.5 --- Aims of the study --- p.39 / Chapter Chapter 2. --- Materials and Methods --- p.41 / Chapter 2.1 --- Materials --- p.42 / Chapter 2.1.1 --- Chemicals --- p.42 / Chapter 2.1.2 --- Primers --- p.42 / Chapter 2.1.3 --- Enzymes --- p.45 / Chapter 2.1.4 --- Cell line --- p.45 / Chapter 2.1.5 --- Collection of specimens --- p.46 / Chapter 2.2 --- Methodology --- p.47 / Chapter 2.2.1 --- "DNA extraction from hcc tissues, cell line Hep3B and PBMCs" --- p.47 / Chapter 2.2.1.1 --- DNA extraction from HCC tissues --- p.47 / Chapter 2.2.1.2 --- DNA extraction from cell line Hep3B --- p.49 / Chapter 2.2.1.3 --- DNA extraction from and PBMCs --- p.50 / Chapter 2.2.1.3.1 --- Preparation of PBMCs --- p.50 / Chapter 2.2.1.3.2 --- DNA extraction from and PBMCs --- p.51 / Chapter 2.2.2 --- Detection of mt whole genome mutation by direct sequencing --- p.51 / Chapter 2.2.2.1 --- Design of mtDNA primers --- p.51 / Chapter 2.2.2.2 --- PCR amplification of the whole mt genome --- p.51 / Chapter 2.2.2.3 --- Direct sequencing of the whole mt genome --- p.52 / Chapter 2.2.2.3.1 --- Primer used in sequencing --- p.52 / Chapter 2.2.2.3.2 --- Purification of the PCR products of the whole mt genome --- p.53 / Chapter 2.2.2.3.3 --- Dye terminator cycle sequencing reaction --- p.53 / Chapter 2.2.2.3.4 --- Purification of extension products --- p.54 / Chapter 2.2.3 --- Detection of mtDNA control region mutation --- p.55 / Chapter 2.2.3.1 --- PCR amplification of D310 in the mtDNA control region --- p.55 / Chapter 2.2.3.2 --- Screening of D310 mutation by PFLDA --- p.55 / Chapter 2.2.3.2.1 --- Making 8% denatured gel mixture --- p.55 / Chapter 2.2.3.2.2 --- Setting up and Pouring the denatured gel --- p.56 / Chapter 2.2.3.2.4 --- Preparing and Loading the PCR products --- p.57 / Chapter 2.2.3.2.5 --- Electrophoresis --- p.57 / Chapter 2.2.3.2.6 --- "Gel fixing, silver staining and color development " --- p.58 / Chapter 2.2.3.3 --- Direct sequencing of D310 in the mtDNA control region --- p.59 / Chapter 2.2.4 --- Detection of mt DNA coding region mutation --- p.60 / Chapter 2.2.4.1 --- PCR amplification of the 5 respiratory chain subunit genes --- p.60 / Chapter 2.2.4.2 --- Restriction enzyme digestion of 5 genes in mtDNA coding region --- p.60 / Chapter 2.2.4.3 --- Screening of mtDNA coding region mutation by SSCP --- p.61 / Chapter 2.2.4.3.1 --- Making 6% 49:1 acrylamide/Bis SSCP gel mixture --- p.61 / Chapter 2.2.4.3.2 --- "Setting up the SSCP gel, loading sample, fixing, staining and developing of the gel " --- p.62 / Chapter 2.2.4.4 --- Sequencing conformation of the mtDNA coding region mutation --- p.62 / Chapter 2.2.5 --- Statistics --- p.63 / Chapter 2.2.5.1 --- The chi-square test --- p.63 / Chapter 2.2.5.2 --- The Friedman test --- p.63 / Chapter 2.2.5.3 --- Wilcoxon signed ranks test --- p.63 / Chapter Chapter 3. --- Results --- p.64 / Chapter 3.1 --- Detection mt DNA whole genome mutation --- p.65 / Chapter 3.1.1 --- Identification of mtDNA whole genome by direct sequencing --- p.65 / Chapter 3.2 --- Detection mt DNA D-loop mutation --- p.76 / Chapter 3.2.1 --- Screening of C-tract alteration in HCC tissus by PCR fragments length detection assay (PFLDA) --- p.76 / Chapter 3.2.2 --- Screening of coding region alteration in HCC tissues by SSCP --- p.77 / Chapter 3.2.2.1 --- Identification of C-tract alterations in HCC and non-tumorous tissues by direct sequencing --- p.77 / Chapter 3.2.3 --- Identification of C-tract alterations by direct sequencing --- p.82 / Chapter 3.2.3.1 --- Identification of C-tract alterations in HCC tissues by direct sequencing --- p.82 / Chapter 3.2.3.2 --- Identification of C-tract alteration in PBMC of normal subjects by direct sequencing --- p.82 / Chapter 3.2.3.3 --- Identification of C-tract alteration in PBMC of HCC patients by direct sequencing --- p.82 / Chapter 3.2.4 --- Statistics of the analysis of C-tract alterations --- p.82 / Chapter 3.3 --- Detection mt DNA mutation in the coding region --- p.87 / Chapter Chapter 4. --- Discussion --- p.98 / Chapter 4.1 --- Detection mtDNA whole genome mutation --- p.99 / Chapter 4.2 --- Detection mtDNA D-loop mutation --- p.107 / Chapter 4.3 --- Detection mtDNA mutation in the coding region --- p.119 / Chapter 4.4 --- Possible mechanisms of mtDNA mutation in HCC carcinogenesis --- p.125 / Chapter 4.5 --- Proposals for prospective studies --- p.126 / Chapter 4.5.1 --- Function of C7 in D310 --- p.128 / Chapter 4.5.2 --- Function changes of mtDNA coding region mutation --- p.130 / Chapter 4.5.3 --- Detection of D310 C-tract mutation in patients' plasma --- p.131 / Chapter 4.5.4 --- Relationship between nMSl and mtMSI --- p.132 / Chapter 4.6 --- Summary --- p.134 / References --- p.137
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Endocrine tumour development : with special focus on chromosome arms 1p and 11q /Nord, Brita, January 2002 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 7 uppsatser.
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Molecular alterations in squamous cell carcinomas of the skin : emphasis on genes on chromosome 9q /Eklund, Lena K., January 2004 (has links) (PDF)
Diss. (sammanfattning) Linköping : Univ., 2004. / Härtill 4 uppsatser.
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Genetic causes of mitochondrial complex I deficiency in childrenHinttala, R. (Reetta) 22 December 2006 (has links)
Abstract
The mitochondrial oxidative phosphorylation system is composed of five multisubunit enzyme complexes. Complex I is the first and largest of these, containing 46 subunits, seven encoded by mitochondrial DNA (mtDNA) and the rest by nuclear DNA. Isolated complex I deficiency is a major cause of metabolic errors in infancy and childhood, presenting as encephalomyopathies or multisystem disorders. Due to the bigenomic origin of complex I, the genetic causes of these defects can be either mitochondrial or nuclear.
The object of the present work was to identify the underlying genetic cause in cases of children with complex I deficiency and to obtain more information on the structurally and functionally important sites of complex I subunits. The complete coding region of mtDNA was analysed by conformation-sensitive gel electrophoresis and subsequent sequencing. In addition, nine nuclear genes encoding conserved subunits of complex I were sequenced. The structural and functional consequences of the new sequence variants were further elucidated using mutagenesis of homologous residue in bacterial NDH-1 or by studying complex I assembly and expression in patient cell lines.
Analysis of the mtDNA coding region in 50 children revealed four definitely pathogenic mutations, 3460G>A, 10191T>C, 11778G>A and 14487T>C, in seven patients. In addition, two novel mtDNA base pair substitutions were identified, 3866T>C in a patient with muscle weakness and short stature and 4681T>C in a patient with Leigh syndrome. The latter mutation causes a Leu71Pro amino acid exchange in the ND2 subunit. Cybrid clones harbouring this mutation retained the complex I defect, and reduced amounts of fully assembled complex I were detected in patient cell lines. The 3866T>C mutation leads to a Ile187Thr amino acid substitution in the ND1 subunit, and functional studies of the homologous amino acid substitution in E. coli showed that this had an effect on the assembly or stability of the NDH-1 holoenzyme. Sequencing of the nine nuclear-encoded complex I genes revealed only one novel base pair substitution with pathogenic potential. Further studies are needed, however, to establish the role of the Arg18Cys substitution in the mitochondrial leading peptide of the TYKY subunit.
The above findings emphasize the contribution of mtDNA mutations to the aetiology of pediatric patients with complex I deficiency. Furthermore, two LHON primary mutations were identified in the present cohort of patients, although the clinical signs differed considerably from the classical symptoms of LHON. This suggests that the phenotype caused by primary LHON mutations is more variable than has so far been thought.
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The role of <em>BACH1</em>, <em>BARD1</em> and <em>TOPBP1</em> genes in familial breast cancerKarppinen, S.-M. (Sanna-Maria) 16 June 2009 (has links)
Abstract
Approximately 5–10% of all breast cancer cases are estimated to result from a hereditary predisposition to the disease. Currently no more than 25–30% of these familial cases can be explained by mutations in the known susceptibility genes, BRCA1 and BRCA2 being the major ones. Additional predisposing genes are therefore likely to be discovered. This study evaluates whether germline alterations in three BRCA1-associated genes, BACH1 (i.e. BRIP1/FANCJ), BARD1 and TOPBP1, contribute to familial breast cancer.
Altogether 214 Finnish patients having breast and/or ovarian cancer were analysed for germline mutations in the BACH1 gene. Nine alterations were observed, four of which located in the protein-encoding region. The previously unidentified Pro1034Leu was considered a possible cancer-associated alteration as it appeared with two-fold higher frequency among cancer cases compared to controls. All the other observed alterations were classified as harmless polymorphisms.
Mutation analysis of the BARD1 gene among 126 Finnish patients having family history of breast and/or ovarian cancer revealed seven alterations in the protein-encoding region. The Cys557Ser alteration was seen at an elevated frequency among familial cancer cases compared to controls (p = 0.005, odds ratio [OR] 4.2, 95% confidence interval [CI] 1.7–10.7). The other alterations appeared to be harmless polymorphisms. To evaluate further the possible effect of Cys557Ser on cancer risk, a large case-control study was performed, consisting of 3,956 cancer patients from the Nordic countries. The highest prevalence of Cys557Ser was found among breast and ovarian cancer patients from BRCA1/BRCA2 mutation-negative families (p < 0.001, OR 2.6, 95% CI 1.7–4.0). In contrast, no significant association with male breast cancer, ovarian, colorectal or prostate cancer was observed.
The current study is the first evaluating the role of TOPBP1 mutations in familial cancer predisposition. The analysis of 125 Finnish patients having breast and/or ovarian cancer revealed one putative pathogenic alteration. The commonly occurring Arg309Cys allele was observed at a significantly higher frequency among familial cancer cases compared to controls (p = 0.002, OR 2.4, 95% CI 1.3–4.2). The other 18 alterations observed were classified as harmless polymorphisms.
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Hereditary predisposition to breast cancer—evaluation of candidate genesRapakko, K. (Katrin) 04 May 2007 (has links)
Abstract
In Western countries, breast and ovarian cancer are among the most frequent malignancies affecting women. Approximately 5–10% of the cases in the general population have been suggested to be attributed to inherited disease susceptibility. BRCA1 and BRCA2 are the main genes associated with predisposition to breast and ovarian cancer. Mutations in these two genes explain a major part of the families displaying a large number of early-onset breast and/or ovarian cancers, but at least one third of the cases appear to be influenced by other, as yet unidentified genes. Therefore, it is likely that defects in other cancer predisposing genes, perhaps associated with lower disease penetrance and action in a polygenic context, will also be discovered.
In the present study, the contribution of germline mutations in putative breast and/or ovarian cancer susceptibility genes, based on their biological function, has been investigated in Finnish breast cancer families. The role of large genomic deletions or other rearrangements in the BRCA1 and BRCA2 genes was evaluated by Southern blot analysis, and mutation analysis of TP53, RAD51, the BRC repeats of BRCA2, and 53BP1 was performed by conformation sensitive gel electrophoresis and DNA sequencing.
Germline TP53 mutations were searched for in 108 Finnish breast cancer families without BRCA1 or BRCA2 alterations. In this study, the pathogenic TP53 germline mutation, Arg248Gln, was identified in only one family. This family showed a strong family history of breast cancer and other cancers also fulfilling the criteria for Li-Fraumeni-like syndrome. Germline TP53 mutations are expected to be found in cancer families with clinical features seen in Li-Fraumeni or Li-Fraumeni-like syndromes.
In this study, large deletions in BRCA1 and BRCA2 were not observed in 82 breast and/or ovarian cancer families. Likewise, no disease-related aberrations were detected in RAD51, the BRC repeats of BRCA2 or 53BP1 in the 126 breast and/or ovarian cancer families studied. The obtained results were validated by comparing to the occurrence in 288–300 female cancer-free control individuals. These results do not support the hypothesis that alterations in these particular genomic regions play a significant role in breast cancer predisposition in Finland. Thus, there are still genes to be discovered to explain the molecular background of breast cancer.
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Melanoma primário da mucosa oral: estudo imunoistoquímico e molecular da via da MAPK / Primary oral mucosal melanoma: an immunohistochemistry and molecular study of MAPK pathwayHsieh, Ricardo 27 June 2012 (has links)
INTRODUÇÃO: O melanoma primário da cavidade oral é uma neoplasia agressiva, rara e originada a partir da proliferação de melanócitos malignos da mucosa. Ele representa aproximadamente de 0,2 a 8% de todos os melanomas. Estudos recentes apontam algumas vias moleculares tem sido encontradas por estarem envolvidas na patogenia dos melanomas. Dentre essas vias destaca-se a via proliferativa da MAPK (mitogen activated protein kinase), esta cascata de sinalização está envolvida no controle do crescimento celular, proliferação e migração, e tem sido relacionada com um papel importante no desenvolvimento e progressão do melanoma cutâneo. OBJETIVOS: Analisar a expressão proteica e mutação pontual dos componentes da via MAPK e correlacionar com os dados clínicos-histológicos. MATERIAL E MÉTODOS: Através da imunoistoquímica avaliar a expressão proteica dos anticorpos RAS; BRAF; MEK1; MEK2; ERK1 e ERK2 em 35 casos de melanomas orais organizados em matriz (TMA: Tissue Microarray) e através de pirosequenciamento avaliar a mutação pontual dos genes BRAF; NRAS; KRAS em 14 casos de melanomas orais. RESULTADOS: Idade dos pacientes entre 9 e 91 anos, sem predileção por sexo, 75% caucasianos, 71,42% acometeram o palato, 80% com aspecto histológico grau III. A análise da expressão proteica foi: RAS (28,57%); BRAF (82,85%); MEK1 (0%); MEK2 (51,43%); ERK1 (20%)e ERK2 (74,28%). Na análise molecular observamos mutações para BRAF (9/14 casos) e NRAS (2/14 casos). CONCLUSÃO: Todos os aspectos da via MAPK necessita de outras elucidações em melanomas de áreas foto-protegidas e melanomas de mucosa e comparando diferentes populações. Entretanto, os resultados deste presente estudo apontam importante alterações na cascata RAS-RAF-MEK-ERK e estes são indicadores de prognóstico ruim em melanomas primários da mucosa oral, independente da exposição solar / BACKGROUND: Primary melanoma of the oral cavity is an aggressive and rare neoplasm and originated from the proliferation of malignant melanocytes of the mucosa. It represents approximately 0.2 to 8% of all melanomas. Recent studies indicate some molecular pathways have been found to be involved in the pathogenesis of melanomas. Among these means there is a proliferative MAPK pathway (\"mitogen activated protein kinase\"), this signaling pathway is involved in controlling cell growth, proliferation and migration, and it has been associated with a role in the development and progression of melanoma skin. OBJECTIVES: To analyze protein expression and mutation of components of the MAPK pathway and to correlate with the clinical, histological data. MATERIALS AND METHODS: Using immunohistochemistry to evaluate the protein expression of RAS, BRAF, MEK1, MEK2, ERK1 and ERK2 antibodies in 35 cases of oral melanomas organized array (TMA: Tissue Microarray) and using pyrosequencing to assess the mutation of the BRAF, NRAS, KRAS in 14 cases of oral melanomas. RESULTS: Age of patients between 9 and 91 years, regardless of gender, 75% Caucasian, 71.42% in palate, 80% with histologic grade III. Analysis of protein expression was: RAS (28.57%); BRAF (82.85%); MEK1 (0%), MEK2 (51.43%); ERK1 (20%) and ERK2 (74.28%). Molecular analysis we found BRAF mutations (9/14 cases) and NRAS (2/14 cases). CONCLUSION: All aspects of the MAPK pathway requires further elucidation in melanomas of photo-protected areas and mucosal melanomas and comparing different populations. However, the results of this study indicate important changes in the cascade RAS-RAF-MEK-ERK and these are indicators of poor prognosis in primary melanomas of the oral mucosa, regardless of sun exposure
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Molecular genetic studies on cystinuriaHarnevik, Lotta January 2007 (has links)
Cystinuria is defined as an inherited disorder characterized by increased urinary excretion of cystine and the dibasic amino acids arginine, lysine and ornithine. The only clinical manifestation of cystinuria is renal cystine stone formation due to the low solubility of cystine in the urine. Cystinuria can be attributed to mutations in the SLC3A1 and SLC7A9 genes in the majority of all cases and it has been a common expectation that molecular genetic studies of cystinuria would aid in understanding of the varying clinical outcome seen in the disease. Besides human, the disease has been most extensively studied in the domestic dog. The present study was undertaken to investigate the molecular genetic basis of cystinuria in patients from Sweden and to correlate genetic findings with phenotypes produced regarding cystine and dibasic amino acid excretion. Further, attempts were made to elucidate the molecular genetics of cystinuria in the dog. The entire coding sequences of the SLC3A1 and SLC7A9 genes were analysed by means of SSCA and DNA sequencing in 53 cystinuria patients and genetic findings were related to urinary excretion of cystine and dibasic amino acids in a subset of the patient group. We detected a total number of 22 different mutations in the SLC3A1 and SLC7A9 genes, 18 of which were described for the first time. We have found a probable genetic cause of cystinuria in approximately 74 % of our patients and a possible contribution to the disease in another 19 %. Mutations in the SLC3A1 gene is the major cause of cystinuria in our group, with only a minor contribution of SLC7A9 mutations. The group of patients presenting SLC3A1 mutations in a heterozygous state or lacking mutations in both genes had higher values of total urinary cystine and dibasic amino acids compared to patients homozygous for SLC3A1 mutations. The reason for this discrepancy remains unclear, but the possible impact of medical treatment with sulfhydryl compounds on total cystine values was ruled out. Sequencing of the full-length canine SLC7A9 cDNA was accomplished using the RACE technology and results from mutation analyses of SLC7A9 and SLC3A1 in cystinuric dogs showed that only two out of 13 dogs have mutations with possible impact on protein function in these genes. DNA sequencing was used for all exons of both genes in the dog, and in human cystinuria patients, all samples lacking mutations or showing heterozygosity after SSCA screening were sequenced in both genes as well. This implies that all point mutations present have been detected, but the possibility of mutations escaping PCR based methods as well as mutations in regulatory parts of the SLC3A1 and SLC7A9 genes remains in cases lacking a full molecular genetic explanation of the disease. Finally, clinical and genetic data from our study of cystinuria both in man and dog exemplifies that manifestation and clinical severity of cystinuria is not determined by genetic alterations in the SLC3A1 and SLC7A9 alone. Environmental factors, congenital malformations and modulating genetic factors are all possible contributors to the clinical outcome of cystinuria.
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Molecular genetic studies on cystinuria /Harnevik, Lotta, January 2007 (has links) (PDF)
Diss. (sammanfattning) Linköping : Linköpings universitet, 2007. / Härtill 4 uppsatser.
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