Dissecting the role of CLASP1 in the mammalian development

A mitose é o evento celular, através do qual uma células transmite uma cópias do seu DNA às células filhas. Este processo é mediado pelo fuso mitótico, o qual consiste numa rede bipolar microtubulos. A dinâmica dos microtubulos é regulada por proteínas associadas a estes (MAPs – Microtubule-Associated Proteins), tais como as proteínas associadas às extremidades positivas dos microtubulos (+TIPs – Plus-ends Tracking proteins). As proteínas associadas às CLIPs (CLASPs – CLIP-associated proteins) pertencem a esta família e estão altamente conservadas nos eucariotas. Estas interagem com os microtubulos regulando o fuso mitótico, a segregação dos cromossomas e o comportamento dos microtubulos ao nível do cinetocoro. Assim, as CLASPs têm sido descritas como essenciais à manutenção da integridade genética durante a divisão celular. Um modelo animal knockout para o gene Clasp1 é uma ferramenta indispensável à descoberta do papel da CLASP1 a nível fisiológico. Nos animais knockout foi observado um fenótipo letal, no qual 100% dos recém-nascidos morreram poucos minutos após o nascimento, no decurso de falência respiratória. Após análise histopatológica, observamos que os pulmões dos animais knockout apresentam um atraso no desenvolvimento. Porém, a análise da expressão de marcadores de diferenciação celular, mostrou que os pneumócitos tipo I e II estão presente e diferenciados nos animais knockout aquando do seu nascimento. No entanto, um defeito primário a nível pulmonar ainda não pode ser excluído. Níveis elevados de glicogénio no parênquima alveolar dos animais knockout sugerem imaturidade pulmonar ou deficiente produção do líquido surfactante. Adicionalmente, ainda não está esclarecido de que forma pode este atraso explicar a letalidade observada nos recémnascidos knockout. Verificamos também que expressão de CLASP1 é transiente ao longo do desenvolvimento, sendo particularmente elevada no cérebro, o que pode explicar o seu papel já descrito na biologia dos neurónios. A CLASP1 é ubiquamente expressa em mamíferos adultos, o que sugere que esta proteína é também importante em tecidos diferenciados. Nesta fase, o significado biológico da CLASP1 em mamíferos ainda não foi descortinado. No entanto, nenhum animal knockout para Clasp1 foi capaz de sobreviver ex uterus, o que sugere um papel fundamental desta proteína na fase final do desenvolvimento dos mamíferos.

Avaliação da satisfação dos dadores do Instituto Português do Sangue - Centro Regional de Sangue do Porto

No contexto da qualidade o grau de satisfação do dador é um indicador importante, permitindo melhorar os serviços e promover o seu retorno. Com o objectivo de avaliar o grau de satisfação dos dadores do IPS-Centro Regional de Sangue do Porto realizou-se estudo descritivo transversal, numa amostra de 512 dadores. Verificou-se que os dadores encontram-se Satisfeitos e Muito Satisfeitos com a instituição e que existe associação entre o grau de satisfação e 5 variáveis independentes. Conclui-se que os recursos humanos IPS-CRSP desempenham a sua função adequadamente, ficando identificada como área para melhoria o alargamento do horário de atendimento.

Neurokinin-1 receptor, a new modulator of lymphangiogenesis in obese-asthma phenotype

Aims Obesity and asthma are widely prevalent and associated disorders. Recent studies of our group revealed that Substance P (SP) is involved in pathophysiology of obese-asthma phenotype in mice through its selective NK1 receptor (NK1-R). Lymphangiogenesis is impaired in asthma and obesity, and SP activates contractile and inflammatory pathways in lymphatics. Our aim was to study whether NK1-R expression was involved in lymphangiogenesis on visceral (VAT) and subcutaneous (SAT) adipose tissues and in the lungs, in obese-allergen sensitized mice. Main methods Diet-induced obese and ovalbumin (OVA)-sensitized Balb/c mice were treated with a selective NK1-R antagonist (CJ 12,255, Pfizer Inc., USA) or placebo. Lymphatic structures (LYVE-1 +) and NK1-R expression were analyzed by immunohistochemistry. A semi-quantitative score methodology was used for NK1-R expression. Key findings Obesity and allergen-sensitization together increased the number of LYVE-1 + lymphatics in VAT and decreased it in SAT and lungs. NK1-R was mainly expressed on adipocyte membranes of VAT, blood vessel areas of SAT, and in lung epithelium. Obesity and allergen-sensitization combined increased the expression of NK1-R in VAT, SAT and lungs. NK1-R antagonist treatment reversed the effects observed in lymphangiogenesis in those tissues. Significance The obese-asthma phenotype in mice is accompanied by increased expression of NK1-R on adipose tissues and lung epithelium, reflecting that SP released during inflammation may act directly on these tissues. Blocking NK1-R affects lymphangiogenesis, implying a role of SP, with opposite physiological consequences in VAT, and in SAT and lungs. Our results provide a clue for a novel SP role in the obese-asthma phenotype.

In vitro transference and molecular characterization of bla TEM genes in bacteria isolated from Portuguese ready-to-eat foods

The principal aim of this study was to investigate the possibility of transference to Escherichia coli of β-lactam resistance genes found in bacteria isolated from ready-to-eat (RTE) Portuguese traditional food. From previous screenings, 128 β-lactam resistant isolates (from different types of cheese and of delicatessen meats), largely from the Enterobacteriaceae family were selected and 31.3% of them proved to transfer resistance determinants in transconjugation assays. Multiplex PCR in donor and transconjugant isolates did not detect bla CTX, bla SHV and bla OXY, but bla TEM was present in 85% of them, while two new TEMs (TEM-179 and TEM-180) were identified in two isolates. The sequencing of these amplicons showed identity between donor and transconjugant genes indicating in vitro plasmid DNA transfer. These results suggest that if there is an exchange of genes in natural conditions, the consumption of RTE foods, particularly with high levels of Enterobacteriaceae, can contribute to the spread of antibiotic resistance.

Photoluminescence and electrical study of fluctuating potentials in Cu2ZnSnS4-based thin films

In this work, we investigated structural, morphological, electrical, and optical properties from a set of Cu2ZnSnS4 thin films grown by sulfurization of metallic precursors deposited on soda lime glass substrates coated with or without molybdenum. X-ray diffraction and Raman spectroscopy measurements revealed the formation of single-phase Cu2ZnSnS4 thin films. A good crystallinity and grain compactness of the film was found by scanning electron microscopy. The grown films are poor in copper and rich in zinc, which is a composition close to that of the Cu2ZnSnS4 solar cells with best reported efficiency. Electrical conductivity and Hall effect measurements showed a high doping level and a strong compensation. The temperature dependence of the free hole concentration showed that the films are nondegenerate. Photoluminescence spectroscopy showed an asymmetric broadband emission. The experimental behavior with increasing excitation power or temperature cannot be explained by donor-acceptor pair transitions. A model of radiative recombination of an electron with a hole bound to an acceptor level, broadened by potential fluctuations of the valence-band edge, was proposed. An ionization energy for the acceptor level in the range 29–40 meV was estimated, and a value of 172 ±2 meV was obtained for the potential fluctuation in the valence-band edge.

Study of optical and structural properties of Cu2ZnSnS4 thin films

Cu2ZnSnS4 is a promising semiconductor to be used as absorber in thin film solar cells. In this work, we investigated optical and structural properties of Cu2ZnSnS4 thin films grown by sulphurization of metallic precursors deposited on soda lime glass substrates. The crystalline phases were studied by X-ray diffraction measurements showing the presence of only the Cu2ZnSnS4 phase. The studied films were copper poor and zinc rich as shown by inductively coupled plasma mass spectroscopy. Scanning electron microscopy revealed a good crystallinity and compactness. An absorption coefficient varying between 3 and 4×104cm−1 was measured in the energy range between 1.75 and 3.5 eV. The band gap energy was estimated in 1.51 eV. Photoluminescence spectroscopy showed an asymmetric broad band emission. The dependence of this emission on the excitation power and temperature was investigated and compared to the predictions of the donor-acceptor-type transitions and radiative recombinations in the model of potential fluctuations. Experimental evidence was found to ascribe the observed emission to radiative transitions involving tail states created by potential fluctuations.

Neurokinin-1 receptor, a new modulator of lymphangiogenesis in obese-asthma phenotype

Aims: Obesity and asthma are widely prevalent and associated disorders. Recent studies of our group revealed that Substance P (SP) is involved in pathophysiology of obese-asthma phenotype in mice through its selective NK1 receptor (NK1-R). Lymphangiogenesis is impaired in asthma and obesity, and SP activates contractile and inflammatory pathways in lymphatics. Our aim was to study whether NK1-R expression was involved in lymphangiogenesis on visceral (VAT) and subcutaneous (SAT) adipose tissues and in the lungs, in obeseallergen sensitized mice. Main methods: Diet-induced obese and ovalbumin (OVA)-sensitized Balb/c mice were treated with a selective NK1-R antagonist (CJ 12,255, Pfizer Inc., USA) or placebo. Lymphatic structures (LYVE-1+) and NK1-R expression were analyzed by immunohistochemistry. A semi-quantitative score methodology was used for NK1-R expression. Key findings: Obesity and allergen-sensitization together increased the number of LYVE-1+ lymphatics in VAT and decreased it in SAT and lungs. NK1-R was mainly expressed on adipocyte membranes of VAT, blood vessel areas of SAT, and in lung epithelium. Obesity and allergen-sensitization combined increased the expression of NK1-R in VAT, SAT and lungs. NK1-R antagonist treatment reversed the effects observed in lymphangiogenesis in those tissues. Significance: The obese-asthma phenotype in mice is accompanied by increased expression of NK1-R on adipose tissues and lung epithelium, reflecting that SP released during inflammation may act directly on these tissues. Blocking NK1-R affects lymphangiogenesis, implying a role of SP, with opposite physiological consequences in VAT, and in SAT and lungs. Our results provide a clue for a novel SP role in the obese-asthma phenotype.

A theoretical study on modelling the respiratory tract with ladder networks by means of intrinsic fractal geometry

Fractional order modeling of biological systems has received significant interest in the research community. Since the fractal geometry is characterized by a recurrent structure, the self-similar branching arrangement of the airways makes the respiratory system an ideal candidate for the application of fractional calculus theory. To demonstrate the link between the recurrence of the respiratory tree and the appearance of a fractional-order model, we develop an anatomically consistent representation of the respiratory system. This model is capable of simulating the mechanical properties of the lungs and we compare the model output with in vivo measurements of the respiratory input impedance collected in 20 healthy subjects. This paper provides further proof of the underlying fractal geometry of the human lungs, and the consequent appearance of constant-phase behavior in the total respiratory impedance.

Sistema de deteção de arritmias

Esta dissertação apresenta o trabalho realizado no âmbito da unidade curricular de Tese/Dissertação (TEDI), do 2º ano, do Mestrado em Engenharia Eletrotécnica e de Computadores no ramo de Automação e Sistemas. O principal objetivo desta dissertação consiste no desenvolvimento de um sistema que permita efetuar a deteção de um determinado número de anomalias num sinal eletrocardiográfico. O coração é um dos órgãos mais importantes do corpo humano. É ele que recebe e bombeia o sangue pelo organismo. Isto é, recebe sangue pobre em oxigénio, encaminha-o para os pulmões onde será enriquecido em oxigénio. O sangue enriquecido em oxigénio é então encaminhado novamente para o coração que será enviado para todas as partes do corpo humano. O eletrocardiograma desempenha um papel fundamental de modo a diagnosticar eventuais anomalias no correto funcionamento do coração. Estas anomalias podem dever-se a diversos fatores como tabaco, colesterol, pressão sanguínea alta ou diabetes entre outros. As anomalias associadas ao ritmo cardíaco são denominadas de arritmias. As arritmias são fundamentalmente originadas pela alteração da frequência ou do ritmo cardíaco. Utilizando a lógica difusa, pretendeu-se desenvolver um sistema que fizesse a identificação de um determinado número de tipos de batimentos entre os quais: o bloqueio do ramo esquerdo (LBBB), bloqueio do ramo direito (RBBB), contração prematura ventricular (VPC) e contração prematura auricular (APC). Todos os desenvolvimentos efetuados, a nível de programação, são neste documento relatados de forma a constituírem um possível guia para a utilização deste tipo de sistemas. Mais ainda, descrevem-se nele toda a pesquisa efetuada e as alternativas de desenvolvimento selecionadas. O Sistema de Deteção de Arritmias (SDA) desenvolvido mostrou-se eficaz desde que o utilizador consiga identificar corretamente os parâmetros que lhe são pedidos. A interface gráfica desenvolvida permitiu também uma maior facilidade durante a análise do sinal eletrocardiográfico.

Bioelectrochemically-assisted reductive dechlorination of 1,2-dichloroethane by a Dehalococcoides-enriched microbial culture

The aim of this study was to verify the possibility to use a polarized graphite electrode as an electron donor for the reductive dechlorination of 1,2-dichloroethane, an ubiquitous groundwater contaminant. The rate of 1,2-DCA dechlorination almost linearly increased by decreasing the set cathode potential over a broad range of set cathode potentials (i.e., from −300 mV to −900 mV vs. the standard hydrogen electrode). This process was primarily dependent on electrolytic H2 generation. On the other hand, reductive dechlorination proceeded (although quite slowly) with a very high Coulombic efficiency (near 70%) at a set cathode potential of −300 mV, where no H2 production occurred. Under this condition, reductive dechlorination was likely driven by direct electron uptake from the surface of the polarized electrode. Taken as a whole, this study further extends the range of chlorinated contaminants which can be treated with bioelectrochemical systems.