Percorrer por autor "Seixas, Maria Teresa"
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- Facts related to the collection of biological samples in the National Health Examination Survey - Portuguese Component of the European Health Examination SurveyPublication . Silva, Marta Barreto da; Francisco, Vânia; Rasteiro, Paula; Sousa, Eduardo; Vicente, A.M.; Bourbon, Mafalda; Martins, Fátima; Seixas, Maria Teresa; Fernandes, Aida; Beleza, Álvaro; Mendonça, Francisco; Gil, Ana Paula; Dias, Carlos MatiasThe objective of the National Health Examination Survey (NHES), which corresponds to the Portuguese component of the European Health Examination Survey (EHES), is to collect health data, related risk factors and biological samples of the Portuguese population, using the EHES recommended methodology. These surveys involve an interview, clinical and physical measurements and blood collection. In this context, we herein describe the pilot study performed in S. Brás de Alportel in the Algarve region. For this pilot study, we have recruited 221 individuals (95 males and 126 females), between 25 and 91 years old, who were enrolled in the Health Centre of S. Brás de Alportel (Algarve). For each participant, we have collected 16.5 ml of total blood, in five different Vacutainer® tubes, which was later processed into serum, plasma and DNA. We have performed several biochemical analyses(total cholesterol, LDL,HDL, glucose, tryglicerides, creatinine, ALT, AST, -GT, CRP and iron) and a complete blood count. From the 221 participants in this pilot study, we were able to collect blood to 219 (99.5%). To 185 of these (84.5%) we were able to collect the total amount of blood. The biochemical analyses were performed in all the samples. The total blood count was performed in 103 samples (47%) due to transport constraints. We have also collected DNA from 210 participants (95.9%). We have created a biobank comprising 1847 serum aliquots and 959 plasma aliquots, which have been stored at - 80°C and 210 DNA aliquots which have been stored at 4°C. In conclusion, during this study, we have optimized the logistics and procedures to perform the large scale study for the NHES and EHES. In addition, we have created a biobank comprising detailed questionnaire data, physical and clinical data and biological samples from a representative sample of S. Brás de Alportel in Algarve, Portugal. This biobank will allow us to perform future studies, including the determination of the prevalence of gene variants of public health interest, the characterization of gene-environment interactions in the development of chronic diseases and the genetic structure of the Portuguese population. The success rate, the quality of the data and of the biological samples was high and comparable to similar studies.
- Hemoglobin variants with electrophoretic mobility similar to hemoglobin SPublication . Miranda, Armandina; Faustino, Paula; Gonçalves, João; Seuanes, Filomena; Copeto, Sandra; Loureiro, Pedro; Costa, Alcina; Costa, Sandra; Seixas, Maria TeresaHemoglobinopathies are among the most common inherited diseases around the world and are one of the world’s major health problems. They are monogenic diseases of autosomal recessive transmission resulting from mutations affecting the genes responsible for the synthesis of globin chains. Abnormal hemoglobins (Hb), named Hb variants, are caused by structural defects resulting from an altered amino acid sequence in globin chains, being Hb S the more frequent and pathogenic/disease associated. The aim of this work was to identify and characterize Hb variants with mobility similar to Hb S when using common laboratorial methodologies, such as isoelectric focusing and high pressure ion exchange chromatography (HPLC). Hemoglobin analysis was performed by isoelectric focusing and HPLC. Globin chain variants were classified in alpha or beta type by reversed phase high performance chromatography. Hb S was confirmed by the solubility test. In order to identify the rare Hb variants, molecular analyses were performed in patient’s DNA. From 2010 to 2016, in the routine practice of our laboratory, 601 cases of variants of Hb were detected with mobility Hb S-like. Amongst them, 433 were confirmed as being Hb S (72.0%). Others hemoglobins also with clinical relevance, Hb D and Hb Lepore, were prevalent, 90 (15.0%) and 61 (10.2%), respectively. The remaining 17 cases were classified as rare (2.8%) and 10 of them were identified by molecular studies as: Hb Maputo (1), Hb G-Coushata (1), Hb Summer Hill (1), Hb Setif (1), Hb G Waimanalo (1), Hb D Iran (1) Hb Oleander (1), Hb Ottawa (1), Hb Etobicoque (1) and Hb Matsue-Oki (1). Hb Matsue-Oki was found in compound heterozygosity with the –α3.7kb-thalassemia deletion. We can conclude that combining the results obtained by the different biochemical methodologies allow the presumptive identification of the more prevalent variants, namely Hb S, Hb D and Hb Lepore, and direct the molecular study for the definitive identification. This study also revealed that several rare variants have similar mobility as Hb S and, consequently, some safety measures should be applied in order to achieve their accurate identification. A correct laboratorial diagnosis is essential for proper patient’s clinical management and genetic counselling.
- Hemoglobinas variantes com mobilidade eletroforética semelhante à da Hemoglobina SPublication . Miranda, Armandina; Seuanes, Filomena; Copeto, Sandra; Loureiro, Pedro; Costa, Alcina; Costa, Sandra; Seixas, Maria Teresa; Gonçalves, João; Gonçalves, João; Faustino, PaulaAs hemoglobinopatias são doenças monogénicas hereditárias, de transmissão autossómica recessiva, resultantes de mutações nos genes codificantes para as cadeias de globina da hemoglobina (Hb), ou nas suas regiões regulatórias. Encontram-se entre as doenças hereditárias mais comuns e constituem um dos principais problemas de saúde a nível mundial.
- Hemoglobinas variantes com mobilidade eletroforética semelhante à da Hemoglobina SPublication . Miranda, Armandina; Seuanes, Filomena; Copeto, Sandra; Loureiro, Pedro; Costa, Alcina; Costa, Sandra; Seixas, Maria Teresa; Gonçalves, João; Faustino, PaulaIntrodução: As hemoglobinopatias são doenças monogénicas hereditárias, de transmissão autossómica recessiva, resultantes de mutações nos genes codificantes para as cadeias de globina da hemoglobina (Hb), ou nas suas regiões regulatórias. Encontram-se entre as doenças hereditárias mais comuns e constituem um dos principais problemas de saúde a nível mundial. As variantes das hemoglobinas são causadas por defeitos estruturais resultantes de alterações na sequência de aminoácidos nas cadeias de globina, sendo a Hb S a mais frequente e associada a patologia. As hemoglobinopatias são as únicas, entre todas as doenças genéticas, em que a deteção de portadores é possível por testes hematológicos e bioquímicos. No entanto, a análise molecular do respetivo gene, deve ser realizada para a identificação definitiva de casos complexos ou quando os resultados hematológicos/bioquímicos não são conclusivos. A identificação de hemoglobinopatias é frequentemente presuntiva, com base em tempos de retenção e padrões de migração, e deve ser baseada preferencialmente no mínimo em duas metodologias com princípios de separação diferentes. A identificação definitiva requer a análise do respetivo gene, espectrometria de massa ou sequenciação de proteínas 1, 2 .Os procedimentos analíticos mais comumente utilizados devem ter capacidade de detetar as variantes de hemoglobina clinicamente mais significativas: Hb S, Hb C, Hb D Punjab, Hb Lepore , Hb E e Hb OArab. .Objetivo: Caraterizar e identificar as variantes de Hb com mobilidade eletroforética semelhante à Hb S..
- Novel large deletions in the human alpha-globin gene cluster: Clarifying the HS-40 long-range regulatory role in the native chromosome environmentPublication . Coelho, Andreia; Isabel, Picanço; Filomena, Seuanes; Seixas, Maria Teresa; Paula, FaustinoGlobin genes, which encode the protein subunits of hemoglobin (Hb), are organized in two different gene clusters and present a coordinated and differential pattern of expression during development. Concerning the human α-globin gene cluster (located at chromosome region 16p13.3), four upstream highly conserved elements known as multispecies conserved sequences (MCS-R1-4) or DNase I hypersensitive sites (HSs) are implicated in the long-range regulation of downstream gene expression. However, only the absence of the MCS-R2 site (HS-40) has proven to drastically downregulate the expression of those genes, and consequently, it has been regarded as the major and crucial distal regulatory element. In this study, Multiplex Ligation-dependent Probe Amplification was used to screen for deletions in the telomeric region of the short arm of chromosome 16, in an attempt to explain the α-thalassemia or the HbH disease present in a group of Portuguese patients. We report four novel and five uncommon deletions that remove the α-globin distal regulatory elements and/or the complete α-globin gene cluster. Interestingly, one of them occurred de novo and removes all HSs except HS-10, while other eliminates only the HS-40 site, the latter being replaced by the insertion of a 39 nucleotide orphan sequence. Our results demonstrate that HS-10 alone does not significantly enhance the α-globin gene expression. The absence of HS-40 in homozygosity, found in a patient with Hb H disease, strongly downregulates the expression of α-globin genes but it is not associated with a complete absence of α-globin chain production. The study of naturally occurring deletions in this region is of great interest to understand the role of each upstream regulatory element in the native human erythroid environment.
- Variantes da hemoglobina com mobilidade eletroforética semelhante à da hemoglobina SPublication . Miranda, Armandina; Seuanes, Filomena; Copeto, Sandra; Loureiro, Pedro; Picanço, Isabel; Costa, Alcina; Costa, Sandra; Seixas, Maria Teresa; Gonçalves, João; Faustino, PaulaAs hemoglobinopatias são doenças genéticas relacionadas com défice da hemoglobina, a proteína vital para o transporte de oxigénio no organismo. De entre elas salienta-se a Drepanocitose causada pela variante S da hemoglobina (HbS) em homozigotia. Neste estudo pretendeu-se identificar as variantes de hemoglobina cujo padrão de migração eletroforética é semelhante ao da HbS. Foram investigados 660 casos de variantes com as características acima referidas detetadas por focagem isoelétrica. Para a identificação presuntiva foi efetuado o teste de solubilidade e a caracterização por HPLC de troca iónica e de fase reversa. A identificação das variantes raras foi efetuada através de sequenciação de Sanger do respetivo gene globínico. De entre os casos estudados, 467 foram confirmados como sendo HbS (70,8%), 101 HbD (15,3%) e 74 HbLepore (11,2%). Os restantes 18 casos (2,7%) foram classificados como variantes raras tendo sido 11 identificadas por sequenciação de DNA. Concluímos que a combinação metodológica utilizada é adequada pois permitiu o correto diagnóstico das variantes mais frequentes e com relevância clínica (HbS, HbD e HbLepore) e, nos casos raros, direcionou o estudo molecular para a análise do gene globínico alterado. A correta identificação de cada variante é essencial para um adequado acompanhamento clínico e aconselhamento genético do doente e seus familiares.