31 research outputs found
Estudo Molecular da Sensibilidade à Varfarina
Folheto técnico sobre o estudo molecular da sensibilidade à varfarina. A varfarina é o anticoagulante oral mais utilizado na terapêutica das doenças cardiovasculares. No entanto, dado
apresentar um intervalo terapêutico muito estreito e uma elevada variabilidade inter-individual na resposta, este
fármaco está associado a episódios hemorrágicos ou trombóticos por inadequação da dosagem administrada.
O Departamento de Promoção da Saúde e Prevenção de Doenças Não TransmissÃveis (DPSPDNT) implementou um
ensaio farmacogenético que permite identificar portadores de determinadas variantes genéticas que conferem
uma maior sensibilidade à varfarina e, por isso, um risco hemorrágico aumentado.N/
Novel large deletions in the human alpha-globin gene cluster: Clarifying the HS-40 long-range regulatory role in the native chromosome environment
Globin 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
Ocorrência e conservação de cetáceos nas águas em torno da Ilha de S. Tomé, arquipélago de São Tomé e PrÃncipe
O arquipélago equatorial de S. Tomé e PrÃncipe está situado no Golfo da Guiné e é constituÃdo por duas ilhas principais e diversos pequenos ilhéus. Determinadas zonas das águas costeiras da ilha de S. Tomé e do ilhéu das Rolas parecem constituir locais de agregação dos cetáceos devido aos seus elevados nÃveis de atividade biológica e potenciais presas. No entanto, em comparação com outras regiões do mundo, muito pouco se sabe acerca das comunidades de cetáceos que ocorrem neste arquipélago. Entre os anos 2002 e 2005 realizou-se um estudo para conhecimento das espécies de cetáceos que ocorrem naquelas águas. Foram observadas seis espécies: baleia-corcunda (Megaptera novaengliae). Golfinho-roaz (Tursiops truncatus), gorfinho-malhado-pantropical (Stenella attenuata), orca (Orcinus ama), cachalote (Physeter macrocephalus) e baleia-pilota (Globioephala spp). Em termos históricos, o arquipélago de S. Tomé e PrÃncipe é referido como uma provável área de reprodução de baleia-corcunda, desde o seculo XIX. Esta espécie, depois de ter sido o alvo principal da baleação comercial, parece estar a voltar a esta região, motivo pelo qual a sua conservação se toma prioritária. O paÃs não possui Iegislação especÃfica para a proteção dos mamÃferos marinhos que ali ocorrem, nem para a regulamentação das atividades humanas que lhes possam estar relacionadas. Neste sentido, é também de referir o crescimento do chamado turismo ambiental e atividades de observação de cetáceos que se tem verificado nos últimos anos naquela região. O presente estudo teve como objetivo a obtenção de dados acerca da ocorrência e distribuição das populações de cetáceos, os quais servirão de base para se criar Iegislação que regulamente as atividades humanas que afetam direta ou indiretamente estas populações. /ABSTRACT: São Tome and PrÃncipe is an equatorial archipelago located in the Gulf of Guinea and formed by two main islands and several islets. This archipelago seems to be an important area for cetaceans. Probably due to large concentrations of prey, as well as the existence of several small bays and shallow water that constitute preferred rest areas. However. in comparison to other areas of the world, little is known about cetacean communities in this archipelago. A biological research to study cetacean's occurrence was conducted between 2002 and 2005. Sightings of humpback whales (Megaptera novaengliae), bottlenose dolphins (Tursiops truncatus), and pantropical spotted dolphins (Stenella attenuata), orcas (Orcinus orca), sperm Whale (Shyster macrooephalus) and pilot whales (Globioephala spp) were recorded. Historically, this archipelago has also been reported as a possible breeding ground of humpback whales in the Gulf of Guinea region since the whaling period. After the end of the commercial whaling humpback whales seems to be returning to this coastal areas and its conservation must face as a priority. Sao Tome and Principe do not have any legislation regarding marine mammals or the marine environment. lt is also important to refer that a significant nature tourism and whale watching industry is presently beginning in the archipelago. The present research allowed obtaining new data on these cetacean’s populations and efforts are being made to create a legal background to regulate human activities that may affect directly or indirectly whales and dolphins' populations
Teachers’ perspectives and practices on biodiversity web portals as an opportunity to reconnect education with nature
Biodiversity loss is a complex issue and a risk that education cannot overlook. Teachers play a crucial role in how biodiversity, and in particular local biodiversity, is understood. To provide insight into how to improve communication on the subject, we investigate teachers’ perspectives and social representations regarding biodiversity, their fluency in terms of Internet use, their familiarity with biodiversity web portals and perceived pedagogical usefulness of technology. A sample of 243 K–12 schoolteachers of multiple scientific domains from eight Azorean islands answered an online survey, including three free-word association tests using inductive terms such as ‘Internet’, ‘biodiversity’ and ‘familiar biodiversity portals’. Overall, the schoolteachers failed to incorporate the multidimensionality of the biodiversity concept (including natural science teachers) or to show technological fluency, and they tended not to use biodiversity web portals as tools to engage students in teaching activities. Our results indicate that teachers’ perspectives about biodiversity need to be broadened and improved and that it is worth exploring whether information and communication technology represents a window of opportunity to do so. As an example, biodiversity web portals, which are widely recognized as trustworthy information repositories, may be used to engage teachers in this endeavour.This work was supported by Portuguese funds through ‘Fundação para a Ciência e a Tecnologia, I.P.’ (FCT), under the project ‘Field Guide’ (PTDC/CED-EDG/31182/2017), the ‘FCT multi-year project 2020– 2023’ (cE3c/GBA UIDB/00329/2020) and by FEDER in 85% and Azorean Public funds in 15% through ‘Operational Program Azores 2020’, under the project AZORESBIOPORTAL–PORBIOTA (ACORES-01-0145-FEDER-000072). IRA was supported by FCT, under the ‘Norma Transitória’ (DL57/2016/CP1375/ CT0003).info:eu-repo/semantics/publishedVersio
Haemolysis in sickle cell anaemia: a genotype/phenotype association study
Sickle-cell anaemia (SCA) is a clinically heterogeneous autosomal recessive monogenic chronic anaemia characterized by recurrent episodes of severe vaso-occlusion, haemolysis and infection. Several genetic and environmental modifiers have been suggested to modulate the onset and course of SCA.
As part of a wider research on the development and validation of vaso-occlusion early predictors in SCA, we have studied the association between haemolysis biomarkers (LDH, total bilirrubin and reticulocyte count) and the inheritance of genetic variants of ten candidate genes in a series of 99 paediatric SS patients (median current age of 9.9 years) followed-up in two general hospitals in Greater Lisbon area (median follow-up/patient of 5.0 years).
Although in a large number of tests a seemingly significant (i.e., p<0.05) association was observed, only the following ones were confirmed upon correction for the false discovery rate: (a) An elevated LDH was associated to haplotype 7 within VCAM1 gene. (b) A lower total bilirrubin was associated to the 3.7kb deletion at HBA gene, rs2070744_T allele and haplotypes 3 and 4 at NOS3 gene and haplotype 9 within VCAM1 gene and rs3783598_G and rs3917024_T alleles at VCAM1 gene promoter. (c) A diminished reticulocyte count was associated to the 3.7kb deletion at HBA gene, whereas an elevated count was associated to rs1984112_G allele at CD36 gene. Furthermore, at the phenotypic level all three haemolysis biomarkers were positively associated to left ventricle dilation, a common chronic complication of SCA.
On the whole, our findings suggest a complex genetic architecture for the haemolytic endophenotype in SCA involving multiple pathways, namely control of erythrocyte volume and haemoglobinisation, vascular cell adhesion, NO synthesis and lipid metabolism. Further mechanistic studies are needed to explore these avenues leading to a better understanding of the inter- and intra-individual clinical variability of SCA.
Acknowledgement: Work partially funded by FCT grants PIC/IC/83084/2007 and CIGMH
Haemolysis in sickle cell anaemia: a genotype/phenotype association study
Introduction: Sickle cell anaemia (SCA) is a clinically heterogeneous autosomal recessive monogenic anaemia characterised by chronic haemolysis and recurrent episodes of severe vaso-occlusion and infection. Several environmental and genetic determinants have been suggested to modulate the onset, course and outcome of SCA.
The level of chronic haemolysis has been considered a critical measure of SCA severity and a possible proximate cause of some disease complications such as stroke, pulmonary hypertension, priapism, leg ulceration and cholelithiasis. Thus, we proposed to search for genetic modifiers of this sub-phenotype and gain insights into the underlying mechanisms.
Patients and Methods: We studied the association between commonly measured haemolysis biomarkers (LDH, total bilirubin and reticulocyte count) and the inheritance of 41 genetic variants (34 SNP, 6 indel, 1 STR) of 10 candidate genes in a longitudinally observed series of 99 paediatric homozygous SCA patients (median current age of 9.9 yr) followed up in two general hospitals in Greater Lisboa area (median follow-up per patient of 5.0 yr). Candidate gene genotyping was performed by PCR-RFLP, Sanger sequencing, Gene Scan or Gap-PCR. All genotype distributions were tested for adherence to the Hardy-Weinberg equilibrium. When appropriate, haplotypes were inferred by software PHASE, version 2.1.1
Results: Although in a large number of tests seemingly significant association was observed only the following ones were confirmed upon correction for multiple comparisons: i) an increased serum LDH level was associated with haplotype 7 within VCAM1 gene; ii) a lower total bilirubin was associated with the 3.7-kb deletion at HBA gene, rs2070744_T allele at NOS3 gene, and haplotype 9 within VCAM1 promoter; and iii) a diminished reticulocyte count was associated with the 3.7-kb deletion at HBA, whereas an increased count was associated with rs1984112_G allele at CD36 gene.
Conclusion: On the whole, our findings suggest a complex genetic architecture for the SCA haemolysis process involving multiple pathways, namely control of vascular cell adhesion, NO synthesis and erythrocyte volume and haemoglobinisation.Partially funded by FCT: PIC/IC/83084/2007 and PEst-OE/SAU/UI0009/201
Cultural probes for environmental education:Designing learning materials to engage children and teenagers with local biodiversity
Direct contact with nature is paramount in deepening children’s and teenagers’ interest in biodiversity. Learning materials chosen to convey information and engage participants during outings in nature-rich environments are varied and can support rich learning experiences. For this purpose, learning materials can be acquired "off-the-shelf" or developed for site-specific locations or projects. However, there is little guidance on potential techniques for those wishing to generate contextually relevant materials. With the view of responding to this challenge, we propose the cultural probes technique. We demonstrate that the technique, commonly used in qualitative research to generate novel insights in conversation with participants, can instigate innovative and thoughtful approaches to materials designed for children and teenagers to explore nature. We present a toolkit that draws on the literature on cultural probes, inquiry-based learning, and the value of sensory, emotional, and aesthetic experiences in environmental education for structuring interactions with participants. To test our approach, we applied a descriptive research design and mixed-methods approach for collecting questions from youths between the ages of 10 and 18, inspired by a nature walk and a set of exploratory tasks executed through the toolkit. Specifically, we tested our toolkit along a trail in the Nature Park of Terceira, situated in the Azores, a Portuguese volcanic archipelago in the North Atlantic. Here, we present and reflect on the data collected during one visit organized over two days with two groups of participants and one post-trail activity directed at both groups. Results demonstrate that the open-ended and playful nature of cultural probes offers a novel way to engage youths with nature-rich environments through questioning. This contribution further highlights the potential of cultural probes for instigating encounters that tap into the value of sensory, emotional, and aesthetic experience in nature, with positive outcomes for participants
Hemoglobin variants with electrophoretic behavior similar to hemoglobin S
As hemoglobinopatias são doenças genéticas relacionadas com défice da
hemoglobina, a proteÃna 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
caracterÃsticas 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 globÃnico. 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. ConcluÃmos que a combinação
metodológica utilizada é adequada pois permitiu o correto diagnóstico
das variantes mais frequentes e com relevância clÃnica (HbS, HbD e
HbLepore) e, nos casos raros, direcionou o estudo molecular para a análise
do gene globÃnico alterado. A correta identificação de cada variante é
essencial para um adequado acompanhamento clÃnico e aconselhamento
genético do doente e seus familiares.Hemoglobinopathies are genetic diseases related to hemoglobin deficiency,
the vital protein for the transpor t of ox ygen in the body. Among
them, the most significant is Sickle Cell Anemia caused by homoz ygosity
for the hemoglobin variant S (HbS). The aim of this work was to identif y
hemoglobin variants with electrophoretic mobility similar to HbS. In this
study we analysed 660 cases of variants with HbS-like mobility in isoelectric
focusing. For the presumptive identification the solubility test was
per formed followed by ion-exchange HPLC and reversed phase-HPLC.
The rare variants identification was per formed by Sanger sequencing of
the corresponding globin gene. Among the evaluated cases, 467 were
confirmed as HbS (70.8%), 101 HbD (15.3%) and 74 HbLepore (11.2%).
The remaining 18 cases (2.7%) were classified as rare variants and 11 of
them were identified by DNA sequencing. We can conclude that the methodological
combination used allows the correct diagnosis of the more
frequent and clinical relevant variants (HbS, HbD and HbLepore) and, in
the other cases, helps to direct the molecular study for the analysis of the
affected globin gene. The correct laboratorial diagnosis of each variant is
essential for the adequate clinical follow-up and genetic counselling of the
patients and their relatives.info:eu-repo/semantics/publishedVersio
The Field Guide app:Connecting island communities to local conservation through mobile interaction
C&T'21: 10th International Conference on Communities & Technologies: Wicked Problems in the Age of Tech - Seattle, United States, June 20–25, 2021.Here we present Field Guide, a mobile application (app) designed to connect communities to nature-rich environments, which play a crucial role in nature conservation efforts. The app aligns to a mode of science communication that seeks to establish direct contact between publics and specialised scientific communities, most commonly known as the ’ask a scientist’ approach. Field Guide uses a geolocation positioning system to offer users the opportunity to pose questions to scientists whilst exploring a nature conservation site. In this demo, we display the app as a mock-up presentation before its first use by children and teenagers during afield-trip to a nature trail later in 2021.The Field Guide project is funded by The Foundation for Science and Technology (FCT), Portugal, grant number PTDC/CEDEDG/31182/2017; IRA was funded by national funds through FCT – Fundação para a Ciência e a Tecnologia, I.P., under the Norma Transitória – DL57/2016/CP1375/CT0003.info:eu-repo/semantics/publishedVersio