Time filter

Source Type

Molinos M.,Institute Engineering Biomedica INEB | Molinos M.,Abel Salazar Biomedical Sciences Institute | Almeida C.R.,Institute Engineering Biomedica INEB | Caldeira J.,Institute Engineering Biomedica INEB | And 5 more authors.
Journal of the Royal Society Interface

Intervertebral disc (IVD) degeneration is one of the major causes of low back pain, a problem with a heavy economic burden, which has been increasing in prevalence as populations age. Deeper knowledge of the complex spatial and temporal orchestration of cellular interactions and extracellular matrix remodelling is critical to improve current IVD therapies, which have so far proved unsatisfactory. Inflammation has been correlated with degenerative disc disease but its role in discogenic pain and hernia regression remains controversial. The inflammatory response may be involved in the onset of disease, but it is also crucial in maintaining tissue homeostasis. Furthermore, if properly balanced it may contribute to tissue repair/regeneration as has already been demonstrated in other tissues. In this review, we focus on how inflammation has been associated with IVD degeneration by describing observational and in vitro studies as well as in vivo animal models. Finally, we provide an overview of IVD regenerative therapies that target key inflammatory players. © 2015 The Author(s) Published by the Royal Society. All rights reserved. Source

Bre L.P.,University of Porto | Bre L.P.,National University of Ireland | Zheng Y.,National University of Ireland | Pego A.P.,University of Porto | And 2 more authors.
Biomaterials Science

Tissue adhesives are a versatile and valuable alternative for wound closure. With fast application, the prevention of body fluid leakage and additional trauma to the wound, adhesives are desirable, especially in friable tissues. Although several options are already in the market, these present some drawbacks, namely poor adhesion in wet substrates and toxicity. Here, the main adhesives both synthetic and biomimetic, commercially available and those still in research, are analyzed with a focus on their adhesion mechanisms. At present, the strongest adhesive able to replace sutures in skin wounds is cyanoacrylate based. However it is toxic and therefore cannot be used internally. More recently alternatives have emerged, with PEG-based adhesives being biocompatible but mainly used as tissue sealants due to their low strength. The most recent approaches under development try to mimic the adhesion strategies of several organisms, such as the extensively studied blue mussels, sandcastle worms, barnacles and geckos. Although no ideal results have been achieved so far, large improvements have been accomplished in the last decade and research is reaching to a new level where the results are starting to meet the needs for medical applications. © 2013 The Royal Society of Chemistry. Source

Goncalves H.,University of Porto | Costa A.,University of Porto | Costa A.,Institute Engineering Biomedica INEB | Ayres-De-Campos D.,University of Porto | And 5 more authors.
Medical and Biological Engineering and Computing

Evaluation of foetal heart rate (FHR) variability is an essential part of foetal monitoring, but a precise quantification of this parameter depends on the quality of the signal. In this study, we compared real FHR beat-to-beat signals with 4 Hz sampling provided by commercial foetal monitors on linear and nonlinear indices and analysed their clinical implications. Simultaneous acquisition of beat-to-beat signals and their 4 Hz sampling rate counterparts was performed using a scalp electrode, during the last hour of labour in 21 fetuses born with an umbilical artery blood (UAB) pH ≥ 7.20 and 6 born with an UAB pH < 7.20. For each case, the first and last 10 min segments were analysed, using time and frequency domain linear, and nonlinear FHR indices, namely mean FHR, low frequency, high frequency, approximate, sample and multiscale entropy. Significant differences in variability indices were found between beat-to-beat and 4 Hz sampled signals, with a lesser effect seen with 2 Hz sampling. These differences did not affect physiological changes observed during labour progression, such as decreased entropy and linear time domain indices, and increased frequency domain indices. However, significant differences were found in the discrimination between fetuses born with different UAB pHs, with beat-to-beat sampling providing better results in linear indices and 4 Hz sampling better results in entropy indices. In conclusion, different FHR sampling frequencies can significantly affect the quantification of variability indices. This needs to be taken into account in the interpretation of FHR variability and in the development of new equipment. © 2013 International Federation for Medical and Biological Engineering. Source

Alves S.M.,Institute Engineering Biomedica INEB | Alves S.M.,University of Porto | Castiglione D.,Escola Nacional de Saude Publica Sergio Arouca | Oliveira C.M.,Institute Engineering Biomedica INEB | And 4 more authors.
Osteoporosis International

Summary: An age-period cohort model was fitted to analyse time effects on hip fracture incidence rates by sex (Portugal, 2000-2008). Rates increased exponentially with age (age effect). Incidence rates decreased after 2004 for women and were random for men (period effect). New but comprehensive fluctuations in risk were coincident with major political/economic changes (cohort effect). Introduction: Healthcare improvements have allowed prevention but have also increased life expectancy, resulting in more people being at risk. Our aim was to analyse the separate effects of age, period and cohort on incidence rates by sex in Portugal, 2000-2008. Methods: From the National Hospital Discharge Register, we selected admissions (aged ≥49 years) with hip fractures (ICD9-CM, codes 820.x) caused by low/moderate trauma (falls from standing height or less), readmissions and bone cancer cases. We calculated person-years at risk using population data from Statistics Portugal. To identify period and cohort effects for all ages, we used an age-period-cohort model (1-year intervals) followed by generalised additive models with a negative binomial distribution of the observed incidence rates of hip fractures. Results: There were 77,083 hospital admissions (77.4% women). Incidence rates increased exponentially with age for both sexes (age effect). Incidence rates fell after 2004 for women and were random for men (period effect). There was a general cohort effect similar in both sexes; risk of hip fracture altered from an increasing trend for those born before 1930 to a decreasing trend following that year. Risk alterations (not statistically significant) coincident with major political and economic change in the history of Portugal were observed around birth cohorts 1920 (stable-increasing), 1940 (decreasing-increasing) and 1950 (increasing-decreasing only among women). Conclusions: Hip fracture risk was higher for those born during major economically/politically unstable periods. Although bone quality reflects lifetime exposure, conditions at birthmay determine future risk for hip fractures. © International Osteoporosis Foundation and National Osteoporosis Foundation 2013. Source

Rodrigues L.R.,University of Campinas | Rodrigues L.R.,National Institute of Science and Technology in Biofabrication INCT BIOFABRIS | Rodrigues L.R.,Institute Engineering Biomedica INEB | Rodrigues L.R.,University of Porto | And 5 more authors.
Materials Research

The sol-gel process is a technique used to synthesize materials from colloidal suspensions and, therefore, is suitable for preparing materials in the nanoscale. In this work hydroxyapatite was used due to its known properties in tissue engineering. Hydroxyapatite Ca10(PO4) 6(OH)2 is a bioactive ceramic which is found in the mineral phase of bone tissue and is known for its great potential in tissue engineering applications. For this reason, this material can be applied as particle aggregates on ceramic slurry, coating or film on materials with a poorer biological response than hydroxyapatite. In this work, hydroxyapatite gel was obtained by the sol-gel process and applied as nanoparticle aggregation in the mixture of hydroxyapatite and tricalcium phosphate to form a ceramic slurry. This process is the polymer foam replication technique used to produce scaffolds, which are used in tissue engineering. For HA gel characterization it was used enviromental scanning electron microscopy (ESEM), transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray fluorescence (XRF). The crystallite size was calculated from XRD data using the Scherrer equation. The nanoparticles size before firing was approximately 5nm. The crystallite size calculated after calcination was approximately 63 nm. The EELS results showed that calcium phosphate was obtained before firing. After HA gel calcination at 500 °C the XRD results showed hydroxyapatite with a small content of beta-TCP. The scaffolds obtained by polymer foam replication technique showed a morphology with adequate porosity for tissue engineering. © 2012. Source

Discover hidden collaborations