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- Low dose irradiation impact on proliferation rate and genetic damage in three-dimensional HepG2 cell culturesPublication . Costa, Pedro; Lemos, Joana; Kocevar, Barbara; Cunha, Lídia; Genésio, Paula; Ponte, Fernanda; Costa, Paulo S.; Sersa, Gregory; Metello, Luís F.Biological effects of low doses of ionizing radiation are not yet consistently studied and documented. In this context, more advanced and complex biological models should be applied to obtain relevant data. Recognizing the need to evolve and develop advanced biological models, in order to try overcome as much as possible known limitations and difficulties of the current monolayer cellular models, as well as the increasing difficulties to use advanced biological models, our group has been working to develop distinct advanced biological alternative models, namely three-dimensional cell cultures.
- Modern Radiobiology: Study of Ionizing Radiation Biological Effects using ThreeDimensional Cell CulturesPublication . Costa, Pedro; Lemos, Joana; Cunha, Lídia; Carvalho, António P.; Vasconcelos, Vítor; Genésio, Paula; Ponte, Fernanda; Costa, Paulo S.; Crespo, Paulo; Metello, Luís F.Biological effects of high doses of ionizing radiation are reasonably well studied and documented. Nevertheless, there is a clear lack of information and/or evidence concerning biological effects of Low Doses, namely at medical imaging levels, as those characterizing Nuclear Medicine and Radiology typical environments. Our group has being involved in the in vitro study of these low dose radiobiological effects. Preliminary experimental results with 100mGy external gamma irradiation of HepG2 monolayer cells showed a slight increase in the proliferation rate 24h, 48h and 72h post irradiation. These preliminary results also pointed into the presence of some Bystander effects 72h post irradiation, constituting the starting point and motivation for the need of a more accurate analysis , here presented.
- O uso de Ferramentas Tecnológicas no Ensino Superior Moderno: abordagem integrada e perspectivas de aplicação em caso práticoPublication . Vieira, Domingos; Costa, Pedro; Cunha, Lídia; Lemos, Joana; Ferreira, Sara; Metello, Luís F.A utilização de ferramentas tecnológicas no Ensino Superior como metodologia de ensino/aprendizagem apresenta-se cada vez mais generalizada. Consciente do facto, a Área Técnico-Científica de Medicina Nuclear da ESTSP.IPP, tem vindo a evoluir na integração gradual de algumas ferramentas tecnológicas na sua realidade específica quotidiana, sempre no sentido de aumentar a qualidade dos serviços que presta e a eficiência do processo, encarado na sua globalidade, acreditando na importante contribuição que podem vir a representar em termos de aumento da competitividade e da facilitação do alcance dos objectivos assumidos, particularmente em termos de ensino à distância e de internacionalização dos diversos projectos pedagógicos em que esta Área se encontra envolvida. Este trabalho tem como objectivo partilhar a experiência adquirida e o estado actual do uso de ferramentas tecnológicas no quotidiano, assim como os próximas etapas previstas no desenvolvimento de este projecto, considerado, por definição, como de longo-prazo. Serão apresentadas uma série de considerações, particularmente em termos da eficácia, inerentes à utilização quotidiana das várias ferramentas que foram já implementadas, sendo ainda tecidas uma série de recomendações e alertas, decorrentes da nossa experiência prática e potencialmente úteis aos que se estão a (ou pretendem) iniciar. O Espaço Europeu do Ensino Superior é declaradamente um desafio major para o qual temos que nos preparar da forma mais eficaz e competitiva, acreditando que a adopção de ferramentas tecnológicas – de uma forma atempada e sobretudo adequada aos objectivos específicos concretos de cada projecto pedagógico – pode vir a constituir um factor decisivo em termos do respectivo sucesso.
- 3D vs 2D Cell Cultures in the Evaluation of Radiobiological Effects of Exposition to Low Doses - Medical Imaging Levels - of Ionizing RadiationPublication . Costa, Pedro; Caires, Hugo; Lemos, Joana; Cunha, Lídia; Bravo, Joana; Bravo, Isabel; Silva, Regina; Summavielle, Teresa; Metello, Luís F.Pretending to develop advanced biological models to study biological effects of low doses of ionizing radiation and following the actual policies on Animal Sciences, based on 3 R’s Rule (to Reduce, Refine and Replace) – that limits as much as possible the application of animal models – scientific research using cellular models is constantly increasing. Nevertheless, the intrinsic limitations of actual cellular models quite often had been recognized on a significant number of papers pointing a significant number of non-concordances between results obtained using in vitro and in vivo studies. Actually, an increasing number of authors admit that three-dimensional cell culture (and spheroid cell culture in particular) could represent an interesting solution and a step further on use of cellular models. The work here to be presented reflects the first phase on the use of this methodology on the study, evaluation and quantification of cellular effects of low doses – starting on medical imaging level - of exposition to ionizing radiation.
- Efeitos Biológicos das Radiações IonizantesPublication . Lemos, Joana; Metello, Luís F.
- Study of the Influence of Patient Hydration in Bone ScintigraphyPublication . Ferreira, Sara; Cunha, Lídia; Osório, Soraia; Matias, Mariana; Lemos, Joana; Vieira, Domingos; Soares, Sofia; Fonseca, Abigaíl; Silva, José Alexandre; Amorim, Inês; Castro, Rosa; Metello, Luís F.The bone scintigraphy is a diagnosis method noninvasive and sensitive in detecting early bone lesions, constituting about 35% of all tests performed in the Service of Nuclear Medicine, of the Hospital of Santo Antonio, in the city of Porto, where the following study took place. One of the important technical details in preparing the patient for this examination is the hydration following the administration of the radiopharmaceutical. The aim of this study focused on assessing the value of hydration on the quality of the image in a bone scintigraphy.
- Is there a need for attenuation correction in the 99mTc-DMSA scans on pediatric patients?Publication . Nogueira, Fábio; Lemos, Joana; Oliveira, Marta; Silva, José A.; Sousa, Maria C.; Cunha, Lídia; Metello, Luís F.Introduction: The quantification of th e differential renal function in adults can be difficult due to many factors - on e of the se is the variances in kidney depth and the attenuation related with all the tissue s between the kidney and the camera. Some authors refer that t he lower attenuation i n p ediatric patients makes unnecessary the use of attenuation correction algorithms. This study will com pare the values of differential renal function obtained with and with out attenuation correction techniques . Material and Methods: Images from a group consisting of 15 individuals (aged 3 years +/ - 2) were used and two attenuation correction method s were applied – Tonnesen correction factors and the geometric mean method . The mean time of acquisition (time post 99m Tc - DMSA administration) was 3.5 hours +/ - 0.8h. Results: T he absence of any method of attenuation correction apparently seems to lead to consistent values that seem to correlate well with the ones obtained with the incorporation of methods of attenuation correction . The differences found between the values obtained with and without attenuation correction were not significant. Conclusion: T he decision of not doing any kind of attenuation correction method can apparently be justified by the minor differences verified on the relative kidney uptake values. Nevertheless, if it is recognized that there is a need for a really accurate value of the relative kidney uptake, then an attenuation correction method should be used.
- Study of Non-Targeted Effects Induced on Cell Lines Using Low Doses of Ionizing RadiationPublication . Caires, Hugo R.; Costa, Pedro; Lemos, Joana; Silva, Regina; Bravo, Isabel; Cunha, Lídia; Metello, Luís F.The LNT - Linear-no-Threshold model, used to analyze dose-effect ratios after biological irradiation exposures, theorizes that effects produced are directly proportional to the irradiating doses, with a linear without threshold pattern. Nevertheless, there is a relevant number of evidence, accumulated essentially over the last decade, suggesting that risks inherent to low doses of irradiation cannot be strictly predicted by the LNT model. Among those, there is a significant number of experimental evidence for a variety of low dose induced biological phenomena, which seems to have an impact on modulating the shape of dose-effect curves, namely for expositions below 0.2 Sv, causing the deviation of LNT model. Accumulated evidence demonstrate that cell irradiation induces biological effects, both to directly irradiated cells as well as to cells not exposed to any kind of ionizing radiation, present in a mixed population. This assumption is breaking the classical idea, based on the belief that damage to cellular DNA is only induced by purely ionizing events in cells directly irradiated. This phenomenon, based on cell communication pathways, is termed “Bystander Effect” - clearly highlighted between the “non-targeted effects” of irradiation not considered by the LNT model - being considered one of the biggest paradigm shifts of modern radiobiology.
- Developing advanced biological models to study effects of low doses of ionizing radiation: our experience.Publication . Lemos, Joana; Costa, Pedro; Cunha, Lídia; Carvalho, António P.; Vasconcelos, Vítor; Silva, Regina; Fernandes, Sílvia; Santos, João; Cunha, Micaela; Crespo, Paulo; Metello, Luís F.; Alves, F.The biological effects of high doses of ionizing radiation are reasonably well studied and documented. Nevertheless, there is a clear lack of evidence concerning biological effects of Low Doses, namely at medical imaging levels, as those characterizing Nuclear Medicine and Radiology typical environments. Recognizing limitations and translational difficulties of the actual monolayer cellular models, our group has produced efforts to develop advanced biological models, namely using three-dimensional cell cultures and a less explored animal model (Zebrafish - which allow access to inter-generational data, while characterized by a great genetic homology). This work aims to exhibit preliminary results already obtained
- Preclinical Imaging: an Essential Ally in Modern BiosciencesPublication . Cunha, Lídia; Horvath, Ildiko; Ferreira, Sara; Lemos, Joana; Costa, Pedro; Vieira, Domingos; Veres, Dániel S.; Szigeti, Krisztián; Summavielle, Teresa; Máthé, Domokos; Metello, Luís F.Translational research is changing the practice of modern medicine and the way in which health problems are approached and solved. The use of small-animal models in basic and preclinical sciences is a major keystone for these kinds of research and development strategies, representing a bridge between discoveries at the molecular level and clinical implementation in diagnostics and/or therapeutics. The development of high-resolution in vivo imaging technologies provides a unique opportunity for studying disease in real time, in a quantitative way, at the molecular level, along with the ability to repeatedly and non-invasively monitor disease progression or response to treatment. The greatest advantages of preclinical imaging techniques include the reduction of biological variability and the opportunity to acquire, in continuity, an impressive amount of unique information (without interfering with the biological process under study) in distinct forms, repeated or modulated as needed, along with the substantial reduction in the number of animals required for a particular study, fully complying with 3R (Replacement, Reduction and Refinement) policies. The most suitable modalities for small-animal in vivo imaging applications are based on nuclear medicine techniques (essentially, positron emission tomography [PET] and single photon emission computed tomography [SPECT]), optical imaging (OI), computed tomography (CT), magnetic resonance imaging (MRI), magnetic resonance spectroscopy imaging (MRSI), and ultrasound. Each modality has intrinsic advantages and limitations. More recently, aiming to overcome the inherent limitations of each imaging modality, multimodality devices designed to provide complementary information upon the pathophysiological process under study have gained popularity. The combination of high-resolution modalities, like micro-CT or micro-MRI, with highly sensitive techniques providing functional information, such as micro-PET or micro-SPECT, will continue to broaden the horizons of research in such key areas as infection, oncology, cardiology, and neurology, contributing not only to the understanding of the underlying mechanisms of disease, but also providing efficient and unique tools for evaluating new chemical entities and candidate drugs. The added value of small-animal imaging techniques has driven their increasing use by pharmaceutical companies, contract research organizations, and research institutions.
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