Searching biocompounds in marine natural extracts with potential use in tumor prevention and treatment

Cancer is a multistage process characterized by three stages: initiation, promotion and progression; and is one of the major killers worldwide. Oxidative stress acts as initiator in tumorigenesis; chronic inflammation promotes cancer; and apoptosis inactivation is an issue in cancer progression. In this study, it was investigated the antioxidant, antiinflammatory and antitumor properties of hexane, ether, chloroform, methanol and water extracts of five species of halophytes: A. macrostachyum, P. coronopus, J. acutus, C. edulis and A. halimus. Antioxidant activity was assessed by DPPH• and ABTS•+ methods, and the total phenolics content (TPC) was evaluated by the Folin-Ciocalteau method. The anti-inflammatory activity of the extracts was determined by the Griess method, and by evaluating the inhibition of NO production in LPS-stimulated RAW- 264.7 macrophages. The cytotoxic activity of the extracts against HepG2 and THP1 cell lines was estimated by the MTT assay, and the results obtained were further compared with the S17 non-tumor cell line. The induction of apoptosis of J. acutus ether extract was assessed by DAPI staining. The highest antioxidant activities was observed in C. edulis methanol and the J. acutus ether extracts against the DPPH• radical; and J. acutus ether and A. halimus ether extracts against the ABTS•+ radical. The methanol extracts of C. edulis and P. coronopus, and the ether extract of J. acutus revealed a high TPC. Generally the antioxidant activity had no correlation with the TPC. The A. halimus chloroform and P. coronopus hexane extracts demonstrated ability to reduce NO production in macrophages (> 50%), revealing their anti-inflammatory capacity. The ether extract of J. acutus showed high cytotoxicity against HepG2 cancer cells, with reduced cellular viability even at the lowest concentrations. This outcome was significantly lower than the obtained with the non-tumor cells (S17). This result was complemented by the induction of apoptosis.

Synthesis and evaluation of polymer nanoparticles for delivery in RPE cells

Ocular pathologies are among the most debilitating medical conditions affecting all segments of the population. Traditional treatment options are often ineffective, and gene therapy has the potential to become an alternative approach for the treatment of several pathologies. Methacrylate polymers have been described as highly biocompatible and are successfully used in medical applications. Due to their cationic nature, these polymers can be used to form polyplexes with DNA for its delivery. This work aims to study the potential of PDMAEMA (poly(2-(N,N’-dimethylamino)ethyl methacrylate)) as a non viral gene delivery system to the retina. The first part of this work aimed to study the potential for gene delivery of a previously synthesized PDMAEMA polymer of high molecular weight (354kDa). In the second part, we synthesized by RAFT a PDMAEMA with a lower molecular weight (103.3kDa) and similarly, evaluated its ability to act as a gene delivery vehicle. PDMAEMA/DNA polyplexes were prepared at 5, 7.5, 10, 12.5 and 20 nitrogen/phosphorous (N/P) ratio for the 354kDa PDMAEMA and at 5 and 7.5 for the 103.3kDa PDMAEMA. Dynamic light scattering and zeta potential measurements confirmed the nanosize and positive charge of polyplexes for all ratios and for both polymers. Both high and low Mw PDMAEMA were able to efficiently complex and protect DNA from DNase I degradation. Their cytotoxicity was evaluated using a non-retinal cell line (HEK293) and a retinal pigment epithelium (RPE) cell line (D407). We have found that cytotoxicity of the free polymer is concentration and time dependent, as expected, and negligible for all the concentrations of the PDMAEMA-DNA polyplexes. Furthermore, for the concentrations to be used in vivo, the 354kDa PDMAEMA showed no signs of inflammation upon injection in the intravitreal space of C57BL/6 mice. The transfection efficiency, as evaluated by fluorescence microscopy and flow cytometry, showed that the D407 retinal cells were transfected by polyplexes of both high and low Mw PDMAEMA, but with varied efficiency, which was dependent on the N/P ratio. Althogether, these results suggest that PDMAEMA is a feasible candidate for non-viral gene delivery to the retina, and this work constitutes the basis of further studies to elucidate the bottleneck in transfection and further optimization of the material.

A fidelização de clientes e as ferramentas de gestão

Este relatório de estágio tenta descrever todo o trabalho levado a cabo pela estagiária num escritório de advogados e baseia-se na tentativa de implementar ferramentas de gestão à fidelização de clientes existentes ou futuros. Constatando que em ciclo recessivo, ou de abrandamento de crescimento económico, existe contração da procura de serviços jurídicos por parte das famílias e por parte das empresas, torna-se essencial inverter a tendência recorrendo a aplicação de ferramentas de gestão para dinamizar a carteira de clientes. A existência de fortes condicionantes ao nível do código deontológico e de sigilo profissional impostos pelo próprio Estatuto da Ordem dos Advogados, inviabilizam os tradicionais meios de captação de clientes, assim como não favorece a captação de novos clientes. O setor da advocacia tem por característica ser um sector tradicionalmente fechado a profissionais da área da gestão e da economia, com a consequente impossibilidade de estes virem a ser sócios destas sociedades civis, o que leva a que sejam setores por vezes inadaptados a novas realidades de gestão para combater ciclo recessivos ou de diminuição da procura. A utilização de ferramentas de gestão como as de Gestão do Relacionamento -CRM, permitirá recolher uma vantagem interna, potenciando clientes atuais e clientes em arquivo “morto”. A gestão da carteira de clientes torna-se assim fundamental para minimizar os impactos dos ciclos económicos menos positivos.

Crescimento, ecologia alimentar e reprodução de Trachurus trecae (Cadenat, 1949), na costa sul de Angola-Namibe

Dissertação de mestrado, Biologia Marinha, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015

New competitors and their intra-industry effects: the case of the hotel industry

Dissertação de Mestrado, Finanças Empresariais, Faculdade de Economia, Universidade do Algarve, 2015