Browsing by Author "Carmo, S."
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- Direct production of 99mTc-Technetium using low energy cyclotrons and radionuclidic purity: our results so far using natMo-MolybdenumPublication . Metelo, Luís Francisco; Costa, Pedro; Cunha, L.; Jonhson, R.; Matei, L.; Gelbart, W.; Obermair, J.; Artner, C.; Lass, P.; Currie, G.; Craciun, L.; Niculae, D.; Carmo, S.; Alves, F.; Botello, M.Despite the global crisis concerning 99mTc delivering to Nuclear Medicine Departments there isn’t yet a reliable solution. The cyclotron direct production of 99mTc, using the 100Mo(p,2n)99mTc nuclear reaction is our attempt to approach the problem, aiming to become efficient, reliable and sustainable from points of view as reducing drastically the radioactive waste being produced and becoming beneficial for all the involved parts. Between several critical factors, radionuclidic purity of cyclotron-produced 99mTc is being pointed as an issue of concern.
- Osteoclastogenic differentiation of human precursor cells over micro- and nanostructured hydroxyapatite topographyPublication . Costa-Rodrigues, Joao; Carmo, S.; Perpétuo, I. P.; Monteiro, F. J.; Fernandes, M. H.Background: Surface topography is a key parameter in bone cells–biomaterials interactions. This study analyzed the behavior of human osteoclast precursor cells cultured over three hydroxyapatite (HA) surfaces ranging from a micro- to nanoscale topography. Methods: HA surfaces were prepared with microsized HA particles, at 1300 °C (HA1), andwith nanosized HA particles at 1000 °C (HA2) and 830 °C (HA3). Human osteoclast precursorswere cultured in the absence or presence of M-SCF and RANKL. Results: HA surfaces had similar chemical composition, however, HA1 and HA3 presented typical micro- and nanostructured topographies, respectively, and HA2 profile was between those of HA1 and HA3. The decrease on the average grain diameter to the nanoscale range (HA3)was accompanied by an increase in surface area, porosity and hydrophilicity and a decrease in roughness. Compared to HA1 surface, HA3 allowed a lower osteoclastic adhesion, differentiation and function. Differences in the cell response appeared to be associated with the modulation of relevant intracellular signaling pathways. Conclusions: The decrease in HA grain size to a biomimetic nanoscale range, appears less attractive to osteoclastic differentiation and function, compared to the HA microsized topography. General significance: This observation emphasizes the role of surface topography in designing advanced biomaterials for tailored bone cells response in regenerative strategies.
- Using low energy medical cyclotrons to produce 99mTc - TechnetiumPublication . Metello, L. F.; Gelbart, W.; Cunha, L.; Carmo, S.; Artner, C.; Alves, F.This paper refers to work in progress, addressing the global trouble in delivering 99mTc to Nuclear Medicine Departments, Aiming to develop an efficient, safe and economical way to directly produce Technetium 99metastable (99mTc) using lowenergy - so-called “medical” - cyclotrons. The present delivery strategy has intrinsic limitations because it is not only based on old nuclear reactors, but also limits the weekly agenda workflow. Our approach is distinct, and is based on the broad distribution network of the low energy cyclotrons and the accessibility of Molybdenum 100 (100Mo) as the target material, so the system here presented, is not based on the use of Nuclear Reactors and highly enriched (or even low enriched) Uranium 235 (235U), but entirely complying with the current international trends and directives, concerning the need to reduce the use of this potential highly critical target material. The direct production technique is based on the nuclear reaction 100Mo(p,2n)99mTc whose production yields have already been widely documented. The 99mTc is produced in a routine, reliable and efficient manner that, remaining always flexible, entirely blends with established protocols.