Browsing by Author "Cabral, Abel Trigo"
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- Strontium-rich injectable hybrid system for bone regenerationPublication . Neves, Nuno; Campos, Bruno B.; Almeida, Isabel F.; Costa, Paulo C.; Cabral, Abel Trigo; Barbosa, Mário A.; Castro Ribeiro, Maria Cristina DeCurrent challenges in the development of scaffolds for bone regeneration include the engineering of materials that can withstand normal dynamic physiological mechanical stresses exerted on the bone and provide a matrix capable of supporting cellmigration and tissue ingrowth. The objective of the present workwas to develop and characterize a hybrid polymer–ceramic injectable systemthat consists of an alginatematrix crosslinked in situ in the presence of strontium(Sr), incorporating a ceramic reinforcement in the form of Sr-richmicrospheres. The incorporation of Sr in the microspheres and in the vehicle relies on the growing evidence that Sr has beneficial effects in bone remodeling and in the treatment of osteopenic disorders and osteoporosis. Sr-rich porous hydroxyapatite microspheres with a uniform size and a mean diameter of 555 μmwere prepared, and their compression strength and friability tested. A 3.5% (w/v) ultrapure sodium alginate solution was used as the vehicle and its in situ gelation was promoted by the addition of calcium (Ca) or Sr carbonate and Glucone-δ-lactone. Gelation times varied with temperature and crosslinking agent, being slower for Sr than for Ca, but adequate for injection in both cases. Injectability was evaluated using a device employed in vertebroplasty surgical procedures, coupled to a texture analyzer in compression mode. Compositions with 35%w ofmicrospheres presented the best compromise between injectability and compression strength of the system, the force required to extrude it being lower than 100 N.Micro CT analysis revealed a homogeneous distribution of themicrospheres inside the vehicle, and a mean inter-microspheres space of 220 μm. DMA results showed that elastic behavior of the hybrid is dominant over the viscous one and that the higher storage modulus was obtained for the 3.5%Alg–35%Sr-HAp-Sr formulation.
- Survival in the elderly following a proximal femur fracture: one-year follow-up studyPublication . Campos, Sónia; Alves, Sandra Maria; Cabral, Abel Trigo; Pina, Maria FátimaThe aim of this study was to determine the one year survival rate after a proximal femur fracture and to investigate the predictors for fatality. All patients that were admitted, with an acute proximal femur fracture caused by a fall of low energy impact from 1 May 2008 - 30 April 2009 in a main portuguese hospital were invited to participate in the study.