Bone allografts in the osteosynthesis of traumatic fractures

Nos últimos anos, assistimos a importantes avanços científicos na área da segurança microbiológica, na imunologia e no conhecimento do comportamento biológico dos aloenxertos do aparelho locomotor, assim como a alterações da legislação que regulamenta as transplantações de orgãos e tecidos de origem humana, o que conduziu a alterações importantes na organização dos Bancos de Tecidos em todo o mundo. Os aloenxertos ósseos podem estar indicados na osteossíntese de fracturas ósseas traumáticas e no tratamento das complicações desse tipo de lesões, área que não tem sido suficientemente divulgada na literatura internacional. No período compreendido entre 1982 e 2007, o BancoTecidos dos HUC disponibilizou 5231 aloenxertos do aparelho locomotor para aplicação clínica. De entre estes e no período compreendido entre os anos 1994 e 2006, foram usados 1078 aloenxertos ósseos na osteossíntese de fracturas ósseas traumáticas e no tratamento de complicações de fracturas, na condição de medida terapêutica complementar: 500 esponjosos granulados, 98 maciços e 480 desmineralizados. O número das fracturas ósseas traumáticas e dos casos com complicações de fracturas foi de 420, distribuídos da seguinte forma: 290 localizados no fémur, 84 na tíbia, 32 no úmero e 14 no rádio. As lesões da extremidade distal do fémur representaram a causa mais frequente da aplicação dos aloenxertos. Nesta série, não foram confirmados casos de infecção associada ao aloenxerto, nem qualquer caso de transmissão de doenças virais aos receptores. A consolidação das fracturas foi conseguida entre os 3 e os 6 meses. Uma reabsorção parcial do enxerto foi verificada em 21 casos (5%), em correlação directa com as deficientes condições vasculares do leito receptor e com a técnica cirúrgica. A aplicação de aloenxerto ósseo no tratamento de fracturas ósseas e das suas complicações é um procedimento seguro e com resultados satisfatórios

Genetically engineered-MSC therapies for non-unions, delayed unions and critical-size bone defects

The normal bone regeneration process is a complex and coordinated series of events involving different cell types and molecules. However, this process is impaired in critical-size/large bone defects, with non-unions or delayed unions remaining a major clinical problem. Novel strategies are needed to aid the current therapeutic approaches. Mesenchymal stem/stromal cells (MSCs) are able to promote bone regeneration. Their beneficial effects can be improved by modulating the expression levels of specific genes with the purpose of stimulating MSC proliferation, osteogenic differentiation or their immunomodulatory capacity. In this context, the genetic engineering of MSCs is expected to further enhance their pro-regenerative properties and accelerate bone healing. Herein, we review the most promising molecular candidates (protein-coding and non-coding transcripts) and discuss the different methodologies to engineer and deliver MSCs, mainly focusing on in vivo animal studies. Considering the potential of the MSC secretome for bone repair, this topic has also been addressed. Furthermore, the promising results of clinical studies using MSC for bone regeneration are discussed. Finally, we debate the advantages and limitations of using MSCs, or genetically-engineered MSCs, and their potential as promoters of bone fracture regeneration/repair.This project is supported by Fundação para a Ciência e a Tecnologia (FCT)—in the framework of the project POCI-01-0145-FEDER-031402-R2Bone, under the PORTUGAL 2020 Partnership Agreement, through ERDF, co-funded by FEDER/FNR, and national funding (through FCT – Fundação para a Ciência e a Tecnologia, I.P., provided by the contract-program and according to numbers 4, 5 and 6 of art. 23 of Law No. 57/2016 of 29 August 2016, as amended by Law No. 57/2017 of 19 July 2017). RG, JHT, and MIA are supported by FCT, through the FCT Investigator Program (IF/00638/2014), SFRH/BD/112832/2015, and DL 57/2016/CP1360/CT0008, respectively

Evaluation of the postharvest quality of Cagaita fruits (Eugenia dysenterica DC.) coated with chitosan and associated with refrigeration

Cagaita fruits are subject to seasonality and perishability. This work aims to use scanning electron microscopy (SEM) to evaluate the physicochemical characteristics, texture, color and physical structure of cagaita fruits coated with different chitosan concentrations. The fruits were divided as follows: T0 (uncoated fruits), T1 (fruits coated with 1% (v/v) chitosan), T2 (fruits coated with 2% (v/v) chitosan) and T3 (fruits coated with 3% (v/v) chitosan). They were analyzed at 0, 10, 20 and 30 days of storage. Titratable acidity and soluble solids content showed no conservation of fruit characteristics; they showed better results for uncoated fruits, as well as weight loss, vitamin C and peak strain. The color of cagaita fruits confirmed ripening during storage regardless of treatment. Scanning electron microscopy showed that the film solution did not adhere, as desired, to the cell wall of fruits. As the results of fruits coated with 3% pectin were close to control, further studies should be carried out with higher coating percentages so that the fruit quality is maintained during storage.Keywords: Physical structure, film solution, quality, shelf life

Supersymmetric Monojets at the Large Hadron Collider

Supersymmetric monojets may be produced at the Large Hadron Collider by the process qg -> squark neutralino_1 -> q neutralino_1 neutralino_1, leading to a jet recoiling against missing transverse momentum. We discuss the feasibility and utility of the supersymmetric monojet signal. In particular, we examine the possible precision with which one can ascertain the neutralino_1-squark-quark coupling via the rate for monojet events. Such a coupling contains information on the composition of the neutralino_1 and helps bound dark matter direct detection cross-sections and the dark matter relic density of the neutralino_1. It also provides a check of the supersymmetric relation between gauge couplings and gaugino-quark-squark couplings.Comment: 46 pages, 10 figures. The appendix has been rewritten to correct an error that appears in all previous versions of the appendix. This error has no effect on the results in the main body of the pape

Learning Interpretable Rules for Multi-label Classification

Multi-label classification (MLC) is a supervised learning problem in which, contrary to standard multiclass classification, an instance can be associated with several class labels simultaneously. In this chapter, we advocate a rule-based approach to multi-label classification. Rule learning algorithms are often employed when one is not only interested in accurate predictions, but also requires an interpretable theory that can be understood, analyzed, and qualitatively evaluated by domain experts. Ideally, by revealing patterns and regularities contained in the data, a rule-based theory yields new insights in the application domain. Recently, several authors have started to investigate how rule-based models can be used for modeling multi-label data. Discussing this task in detail, we highlight some of the problems that make rule learning considerably more challenging for MLC than for conventional classification. While mainly focusing on our own previous work, we also provide a short overview of related work in this area.Comment: Preprint version. To appear in: Explainable and Interpretable Models in Computer Vision and Machine Learning. The Springer Series on Challenges in Machine Learning. Springer (2018). See http://www.ke.tu-darmstadt.de/bibtex/publications/show/3077 for further informatio