Browsing by Author "Costa, Pedro"
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- 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.
- 45Ti - Titanium: from cyclotron production to potential applications evaluationPublication . Costa, Pedro; Metello, Luís F.; Cunha, Lídia; Lass, Piotr; Currie, Geoff; Johnson, Richard R.; Gelbart, W.; Obermair, J.; Artner, Christoph; Alves, Francisco; Naia, M. DuarteIntroduction: Thousands of radioisotopes are known and virtually all may be artificially produced, however clinical applications of PET imaging are mainly based on 18F, 11C, 13N and 68Ga. This trend could change in the near future, since several groups worldwide are busy developing very promising new entities aiming to contribute for spreading the use and efficacy of clinical diagnostic using Nuclear Medicine imaging techniques. Our group is developing 45Ti-Titanium, assuming it as a potential candidate, since presenting interesting properties: physical half-life of 3.09h, together with relevant chemical properties, that enable radiolabelling with bifunctional chelates, ligands or could even be useful for studies concerning the distribution of new titanium-based chemotherapy drugs or titanium oxide nanoparticles. Considering that data characterizing excitation functions is necessary for radionuclide optimal production, this work aims to disseminate results regarding the determination of excitation function of 45Sc(p,n)45Ti reaction, studied as a potential route to produce 45Ti in low energy cyclotrons.
- 99mTc-MAA for Lung Perfusion Scintigraphy: Impact of Counting Method on the Effective Number of Particles Administered and Particle Aggregation Over TimePublication . Costa, Pedro; Cunha, Lídia; Soares, Sofia; Mendes, Ângela; Queiroz, Ana; Nunes, Amélia; Ferreira, Elisabete; Botelho, Elisa; Sousa, Maria C.; Castro, Rosa; Pires, Laucena; João, M. Faria; Metello, Luís F.: 99mTc-MAA (macroaggregates of albumin) is the selected radiopharmaceutical for the Lung Perfusion Scintigraphy. It is retained in lung capillaries by mechanical blockage resulting in local microembolization. Care should be taken concerning not only particle size but also the number of particles administered to patients, particularly those who present with special conditions (pulmonary hypertension, shunt or lung transplant). European Pharmacopoeia only requires the assessment of particle size. This work aims to characterize particle size and particle aggregation of two commercial brands of MAA kits and to compare particle counting methods
- 99mTc-MAA for Lung Perfusion Scintigraphy: Impact of Counting Method on the Effective Number of Particles Administered and Particle Aggregation Over TimePublication . Costa, Pedro; Cunha, Lídia; Soares, Sofia; Mendes, Ângela; Queiroz, A. Isabel; Nunes, Amélia; Ferreira, Elisabete; Botelho, Elisa; Sousa, Conceição; Castro, Rosa; Pires, Laucena; João, M. Faria; Metello, Luís F.Introduction: 99mTc-MAA (macroaggregates of albumin) is the selected radiopharmaceutical for the Lung Perfusion Scintigraphy. It is retained in lung capillaries by mechanical blockage resulting in local microembolization. Care should be taken concerning not only particle size butalso the number of particles administered to patients, particularly those who present with special conditions (pulmonary hypertension, shunt or lung transplant). European Pharmacopoeia only requires the assessment of particle size. This work aims to characterize particle size and particle aggregation of two commercial brands of MAA kits and to compare particle counting methods.
- Acetyl-L-Carnitine Improves Cell BioenergeticsPublication . Cunha, Lídia; Bravo, Joana; Costa, Pedro; Fernandes, Sílvia; Oliveira, Marta; Castro, Rosa; Metello, Luís F.; Summavielle, TeresaIntroduction: Acetyl-L-Carnitine (ALC), a natural occurring compound in all mammalian species, plays a variety of vital functions in the body. The most important are related to mitochondria, namely the transport of fatty acids for energy production through β oxidation and the control of acyl-CoA/CoA ratio. Due to this close interaction with cell bioenergetics, it plays a role in many diseases, especially those related to the mitochondria. We propose to characterize the action of ALC in mitochondrial bioenergetics and functional integrity.
- Application of Monte Carlo simulation codes to plan an activation experiment in Scandium-45 targetsPublication . Costa, Pedro; Metello, Luís F.; Alves, Francisco; Naia, M. DuarteData characterizing excitation functions of nuclear reactions are necessary for different applications, with the process of radionuclide production being assumed as a relevant example. This is the only way to define and optimize technical parameters involved in such a process. However, nuclear activation experimental studies are sometimes difficult to implement, and care should be taken before its execution, in order to obtain all relevant data, while correctly planning the experiences. In this context, Monte Carlo simulation tools are widely applied to overtake such difficulties. This work describes a case-study aiming to characterize nuclear reactions excitation functions induced by a proton beam and its interaction with a Scandium target – a specific situation that is not yet completely characterized and that might be of relevance, since it could be useful to produce medically relevant radionuclides (eg. Titanium-45).
- Assessing left ventricular dysfunction by the use of three distinct molecular imaging techniquesPublication . Reis, J.; Cunha, L.; Costa, Pedro; Neves, D.; Oliveira, T.; Ferrer-Antunes, A.; João, M. Faria; Metelo, Luís FranciscoLeft ventricular dysfunction might be assessed using distinct molecular imaging modalities. The most relevant are first pass radionuclide ventriculography (FPRV), multigated radionuclide angiography (MUGA) and gated blood-pool SPECT (GBPS) and are very often used for monitoring chemotherapy-related cardiomyopathy. This work aims to correlate these three molecular imaging techniques.
- Assessing radiobiological effects of diagnostic level doses of ionizing radiation on zebrafish using comet assayPublication . Lemos, Joana; Costa, Pedro; Cunha, Lídia; Carvalho, António Paulo; Neuparth, Teresa; Genésio, Paula; Ponte, Fernanda; Costa, Paulo; Crespo, Paulo; Metello, Luís F.This paper relates with the application of zebrafish – Danio rerio – to the study of radiobiological effects of medical diagnostic level – low doses – of ionizing radiation. In recent years, the use of zebrafish has grown considerably, pointing more and more as a very interesting model in biomedical research, essentially because of the level of homology shared with the human genome, complemented by an easy and reasonably affordable practical side.
- Assessing Radiobiological Effects of Low Doses of Ionizing Radiation on Zebrafish by Bidimensional Gel ElectrophoresisPublication . Lemos, Joana; Costa, Pedro; Cunha, Lídia; Campos, Alexandre; Carvalho, António Paulo; Vasconcelos, Vítor; Genésio, Paula; Ponte, Fernanda; Costa, Paulo; Crespo, Paulo; Metello, Luís F.Aim: This paper relates with a specific task from a larger research project oriented to the development and application of the Zebrafish – Danio rerio – to the study of radiobiological effects of medical diagnostic level – low doses – of ionizing radiation.
- Assessing radiobiological effects of low doses of ionizing radiation on zebrafish muscle by two-dimensional gel electrophoresisPublication . Lemos, Joana; Campos, A.; Carneiro, M.; Ribeiro, T.; Ponte, F.; Costa, Pedro; Cunha, L.; Carvalho, A.; Metelo, Luís FranciscoThis work relates with the application of zebrafish - Danio rerio - to the study of radiobiological effects of low doses of ionizing radiation. In recent years, the use of zebrafish has grown considerably, pointing more and more as a very interesting model in biomedical research, essentially because of the level of homology shared with the human genome, complemented by an easy and reasonably affordable practical side.