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- Superparamagnetic hybrid microspheres affecting osteoblasts behaviourPublication . Fernandes Patrício, Tatiana Marisa; Panseri, Silvia; Montesi, Monica; Iafisco, Michele; Sandri, Monica; Tampieri, Anna; Sprio, SimoneThe present work describes biomimetic hybrid microspheres made of collagen type I-like peptide matrix (RCP) mineralised with Fe2+/Fe3+ doping hydroxyapatite (RCPFeHA) by a bio-inspired process. Superparamagnetic RCPFeHA microspheres are obtained by emulsification of the hybrid slurries in the presence of citrate ions, to achieve a biomimetic surface functionalisation improving the bioactivity and the dispersion ability in cell culture medium. A biological in vitro study correlates the osteoblast cells behaviour to calcium and iron ions released by the hybrid microspheres in culture media mimicking physiological or inflammatory environment, evidencing a clear triggering of cell activity and bio-resorption ability. In presence of the microspheres, the osteoblast cells maintain their typical morphology and no cell damage were detected, whereas also showing up-regulation of osteogenic markers. The ability of the hybrid microspheres to undergo bio-resorption and release bioactive ions in response to different environmental stimuli without harmful effects opens new perspectives in bone regeneration, as magnetically active bone substitute with potential ability of drug carrier and smart response in the presence of inflammatory states.
- Evaluation of Procalcitonin Accuracy for the Distinction Between Gram-Negative and Gram-Positive Bacterial Sepsis in Burn PatientsPublication . Cabral, Luís; Afreixo, Vera; Meireles, Rita; Vaz, Miguel; Frade, João Gonçalo; Chaves, Catarina; Caetano, Marisa; Almeida, Luís; Paiva, José-ArturSepsis is the main cause of death in burns. Early institution of antimicrobial therapy is crucial to optimize outcomes but superfluous therapy increases adverse events, microbial resistance, and costs. Blood cultures are the gold standard for diagnosis but can take 48 to 72 hours. Biomarkers are used to help sepsis diagnosis and distinction between Gram-negative and Gram-positive bacterial cause. The aim of this work is to evaluate procalcitonin (PCT) accuracy for this distinction in burn patients. Retrospective observational study of adult septic burn patients with ≥15% total burn surface area admitted from January 2011 to December 2014 at a Burn Unit in Portugal. A statistical analysis was done, evaluating the correlation between PCT levels on the day of the first positive blood culture and microbiological data for Gram-negative and Grand-positive bacteria. Patients with mixed bacterial and/or fungal blood cultures were excluded. Data were summarized by quartiles statistics. Blood cultures were positive in 189 patients: 75 (39.7%) showed growth for Gram-negative and 114 (60.3%) for Gram-positive bacteria. Patients with Gram-negative bacteria have significantly higher PCT levels. Receiver operating characteristic curve analysis showed accuracy for Gram-negative discrimination with area under the curve = 0.687. Most elevated levels were related to nonfermentative Gram-negative bacteria and by Klebsiella pneumoniae and other Enterobacteriaceae. PCT levels were significantly higher in burn patients with Gram-negative sepsis comparing to patients with Gram-positive sepsis and controls. The determination of PCT levels may help the choice of empirical antimicrobial therapy while microbiological culture results are not available, despite not fully ensuring the desirable degree of precision.