Novas abordagens para o rastreio do cancro do colo do útero e para a prática clínica

Tese de mestrado, Biologia (Microbiologia Aplicada), 2009, Universidade de Lisboa, Faculdade de CiênciasA infecção persistente por um dos 15 Vírus do Papiloma Humano (HPV) de alto risco é considerada um factor necessário, mas não suficiente, para o desenvolvimento do cancro do colo do útero. Nos últimos anos, tem-se assistido a uma intensa procura de novos métodos moleculares de diagnóstico que permitam diferenciar entre as mulheres cujas lesões vão progredir para carcinoma invasivo e aquelas cujas lesões regredirão espontaneamente. No presente trabalho, foram desenvolvidas e implementadas metodologias de PCR em tempo real para a quantificação da carga viral, o estudo do estado físico do genoma viral na célula hospedeira e a quantificação dos transcritos dos oncogenes virais do HPV 16 e 18, com vista à identificação de indicadores de prognóstico para o desenvolvimento do cancro do colo do útero. A quantificação do DNA do HPV 16 e 18 permitiu identificar uma correlação positiva entre a carga viral e a gravidade da lesão. O estudo do estado físico do DNA do HPV 16 e 18, embora não tenha permitido estabelecer uma relação prognóstica entre o estado físico do DNA viral e o tipo de lesão, permitiu constatar que a integração do DNA do HPV 16 é um acontecimento precoce e que as formas exclusivamente integradas do HPV 18 aumentam com a gravidade da lesão. A quantificação do RNAm do E7 do HPV 16 permitiu estabelecer uma associação positiva entre a expressão dos transcritos virais e o grau da lesão. No caso do HPV 18, o pequeno número de casos estudados não permitiu estabelecer uma correlação. De acordo com os resultados obtidos, para além da tipificação dos HPV de alto risco, a quantificação da carga viral poderá ser um importante biomarcador para a identificação precoce dos casos com maior probabilidade de progressão e desenvolvimento de carcinoma do colo do útero e lesões percursoras.Persistant infection with one of the 15 high-risk human papillomaviruses (HPV) is a necessary but insufficient cause of cervical cancer development. In the last few years, there has been an intense pursuit for new molecular diagnostic methods that allow the differentiation between women whose lesions are destined to progress to invasive carcinoma and those whose lesions will spontaneously regress. In the present study real-time PCR methodologies for viral load quantification, for the assessment of the physical status of HPV DNA in the host genome and for the quantification of viral oncogene transcripts of HPV 16 and 18, were developed and implemented, aiming at finding prognostic indicators for the development of cervical cancer. Although the study of HPV 16 and 18 physical did not allow the establishment of a prognostic association between viral DNA physical status and lesion grade, it did allow the conclusion that HPV 16 DNA integration is an early event and that HPV 18 integrated-only forms increased with lesion severity. HPV 16 E7 mRNA quantification allowed the determination of a positive correlation between the level of viral transcripts expression and lesion grade. In the case of HPV 18, due to small sample size, no correlation was established. According to the results obtained, viral load, in addition to high-risk HPV testing, could become an important biomarker for the early identification of cases with increased probability of progression and development of cervical carcinoma and precursor lesions

The causes of unsuccess of entrepreneurial practices from technological start-ups

The purpose of this research is to study the main features of successful technological start-ups, to validate if the theory that is shown in this paper applies to reality, defining some guidelines that allow entrepreneurs to better understand what variables contribute to achieve success or failure. The scope of this research is focused on two very trending areas nowadays: entrepreneurship and technology. Both contribute a great deal to the country’s evolution in which they are operating and it’s respective competitive advantage, they also help developing the economy, job creation and to increase knowledge and skills of their workforce. The methodology consisted on a survey performed to a group of technological entrepreneurs, distinguishing the successful experiences from the unsuccessful ones. This approach allows one to identify some important correlations on both cases. The main conclusions that came from the survey were that successful entrepreneurs have bigger experience, with good management skills and market sensitivity. On the other hand, the unsuccessful entrepreneurs that were studied seemed to lack proactivity and overall accurate planning, with their biggest constraint being the time-to-market. In the end, this study is intended to help technological entrepreneurs to understand some of the requirements needed to start/adapt their business in the best way to achieve the success of their venture.O objetivo deste estudo é analizar as principais características de start-ups tecnológicas bem sucedidas, permitindo validar se a teoria que nesta dissertação é levantada se aplica à realidade, definindo, desta forma, algumas linhas de orientação que permitam ao empreendedor perceber que variáveis contribuem para que atinja o sucesso ou o fracasso. O âmbito da presente dissertação evoca duas temáticas muito em voga nos dias de hoje: empreendedorismo e tecnologia. Ambas contribuem visivelmente para a evolução do país em que se enquadram e respetiva vantagem competitiva, auxiliando no desenvolvimento da economia, criação de emprego, aumento do conhecimento e competências. A metodologia utilizada consistiu num inquérito realizado a um grupo de empreendedores do setor tecnológico, distinguindo os casos de sucesso dos de insucesso. Esta abordagem permitiu identificar algumas correlações que parecem importantes em ambos os casos. As principais conclusões que advieram desta dissertação identificam que os empreendedores de sucesso têm maior experiência, bons conhecimentos de gestão e conhecimento do mercado no qual entram. Por outro lado, os empreendedores entrevistados que não foram bem sucedidos aparentam falta de proatividade e de planeamento detalhado nos seus negócios, sendo que a maior dificuldade para este grupo está relacionada com o tempo que demora a entrar no mercado desejado. Este estudo pretende ajudar os empreendedores do setor tecnológico a compreender alguns dos requisitos necessários para começar/adaptar o seu negócio à melhor forma de atingir o sucesso do mesmo

Optimal Interest Rate Rules in Inflation Targeting Frameworks

This work describes the main characteristics of an inflation targeting regime and derives the optimal solution for interest rates according to an original methodology for two models based on the Phillips and IS curves containing general exogenous variables and a complete loss-function.

r-filters: a Hodrick-Prescott Filter Generalization

A two-parameter family of filters is proposed in which the HP filter is considered as the lowest order member. While the HP filter converges to linear time trend as the smoothing factor grows, the higher order members of the proposed family converge to higher order polynomial time trends. The filter order - the new parameter introduced - allows to set the filter selectivity. Furthermore, two different methods to implement these filters are presented.

The Will-to-Live Scale: validity and reliability among portuguese adolescents

This work presents psychometric analyses of the Will-to-Live Scale (WTLS) among Portuguese adolescents. Two studies were carried out to establish the psychometric characteristics of the WTLS. Findings of both studies pointed out that the WTLS has satisfactory reliability and validity. Principal component analysis and confirmatory factor analysis of the WTLS evidenced a unidimensional structure. Different types of reliability estimates of the WTLS were also good. Findings also supported the convergent validity of the WTLS through significant positive correlations, between will-to-live and life satisfaction, satisfaction with family life, positive affect, self-esteem, and emotional intelligence, and negative associations with negative affect, depression, anxiety, and stress. Findings of this research indicate that the WTLS is a valid and reliable tool among Portuguese adolescents

Psychometric evaluation of the Portuguese Satisfaction with Family Life Scale

The purpose of this study is to examine the psychometric properties of the Satisfaction with Family Life Scale (SWFLS) among Portuguese adolescents. This scale assesses a person’s global evaluation of family satisfaction. The participants were 252 high school students from public schools in Lisbon, aged 15–19 years (M = 16.87; SD = 1.21). Confirmatory factor analysis confirmed a one-factor model of the SWFLS among Portuguese adolescents. The SWFLS showed adequate psychometric properties, with good internal consistency. Subsequent analyses indicated that the SWFLS scores were related to a measure of family satisfaction, as well as wellbeing (life satisfaction, self-esteem) and current interpersonal functioning (social support and loneliness). These findings are interpreted as supporting the validity of the SWFLS. The findings of this research indicate that the Portuguese version of the SWFLS is a brief, psychometrically sound instrument to assess family life satisfaction

Tracking relations among bacterial and protozoan communities in wastewater treatment plants

Background: Understanding the interactions between prokaryotic and eukaryotic populations in complex environments can be challenging. Particularly, there is a recognized difficulty in establishing how the interactions between the bacterial and the protozoan populations can affect the performance of wastewater treatment plants (WWTP). Objectives: In order to determine the relationships between microbial communities (protozoa, metazoa and filamentous bacteria) and abiotic parameters (physical-chemical and operational), thirty seven WWTP with activated sludge process were studied in Portugal, during two years, in a trimestral sampling strategy. Methods: Samples were collected to enable a molecular characterization of the microbiota. In order to ensure the diversity of microorganisms, 100 samples were selected based on their geographic localization and time-spaced to track relationships within bacteria and protozoa. A 16S rRNA gene PCR-DGGE approach was carried out for bacterial community fingerprinting. The resulting profiles were analysed together with the results obtained from the survey of the protozoa populations. Finally, the study of the correlations between the physical-chemical and operational parameters and the microbial communities was also investigated. Conclusions: The study of these interactions constitutes a strategy for the understanding of how the different metabolic groups of prokaryotic and protozoa are affected by the relations between this populations, allowing a better prediction of the overall community dynamics. This will allow setting the conditions that better contribute to improve the wastewater treatment while increasing the knowledge of overall communities networking in complex environments

Interactions between eukaryotic and prokaryotic microorganisms in activated sludge: a molecular approach to improve wastewater treatment

Wastewater treatment is one of the most important biotechnological processes which are used worldwide to treat municipal and industrial sewage. Activated-sludge processes aim to achieve a maximal reduction of the Biological Oxygen Demand (BOD) of wastewater with a minimal production of biological solids. Even though many microbiological methods are available to study the activated sludge communities, many recent questions on the role of certain microorganisms are kept unanswered. A crucial addressed by the present work is to know if the presence of different groups of bacteria and protozoa lead to significant consequences on the process performance. Focusing on the importance of the interactions between the prokaryotic and the eukaryotic populations, the work will contribute to the knowledge of how microbial communities are established in a complex environment as the activated sludge processes

Prokaryotic and eukaryotic populations in activated-sludge

Protozoa play a direct role by reducing through grazing the amount of freely-suspended and loosely-attached bacterial cells. Also, filamentous bacteria, although endangering the performance of wastewater treatment plants (WWTP), should be considered as normal components of the activated-sludge microbial community.Correlations between plant performance and the abundance of certain species have been studied, being the Sludge Biotic Index (1) the best known method to assess the activated-sludge plant performance through the analysis of protozoa and small metazoan communities. However, few studies have established reliable relationships between the prokaryotic and eukaryotic populations (2). The present work presents data on the prevalence, abundance and distribution of protozoa, small metazoa and filamentous bacteria on 37 activated-sludge Portuguese WWTP operating under different environmental conditions, during one year, including data on the correlations between the prokaryotic and eukaryotic components. The most frequent protozoa were the crawling (CC) and the attached sessile (ASC) ciliates, being Aspidisca cicada, Epistylis spp. and Microthorax sp. the most abundant. The most frequent filamentous bacteria were Types 0041/0675, 0092, 1851, Nocardioforms, Microthrix parvicella, Nostocoida limicola II and Haliscomenobacter hydrossis; only the former four were found dominant in all samples. Correlations were found to be significantly positive (p<0,05) between Nostocoida limicola II and Type 0092 and negative between Thiothrix II and Microthrix parvicella. Correlations between filamentous bacteria and protozoa were significantly positive (p<0,05) for freely swimming ciliates (FSC) and Type 0092 and for flagellates (F)/Thiothrix II. Negative correlations were found for FSC and Microthrix parvicella, F and Nocardioforms