In vitro monitoring of surface mechanical properties of poly(L-lactic acid) using microhardness

Poly(L-lactic acid) (PLLA) was immersed in a simulated body fluid (SBF) solution at 37.58C for distinct times. The variation of the surface mechanical properties of PLLA samples with immersion time was followed by microhardness. These measurements showed that PLLA microhardness decreased significantly ( 60%) after only 30 days of immersion. The results were explained in terms of hydrolytic degradation of the samples. The dependence of microhardness with the applied dwell time was also analyzed. The creep curves were successfully described by a power law. A decrease of the creep constant k as the immersion time increased was found. Differential scanning calorimetry was also used to analyze the changes in the physical properties of PLLA, namely in crystallinity degree (Xc) and glass transition temperature (Tg), as a function of the immersion time in SBF. A significant variation in the crystallinity degree of PLLA, initially nearly amorphous (Xc 5 9%), was detected after only 3 days of immersion (Xc 5 37%). The interpretation of this behavior was based on the hydrolysis process suffered by PLLA

Microhardness of starch based biomaterials in simulated physiological conditions

In this work the variation of the surface mechanical properties of starch-based biomaterials with immersion time was followed using microhardness measurements. Two blends with very distinct water uptake capabilities, starch/cellulose acetate (SCA) and starch/poly- (e-caprolactone) (SPCL), were immersed in a phosphate buffer solution (PBS) at 37.5 C for various times. The microhardness of the blends decreased significantly ( 50% for SPCL and 94% for SCA), within a time period of 30 days of immersion, reflecting the different hydrophilic character of the synthetic components of the blends. The dependence of microhardness on the applied loading time and load was also analysed and showed a power law dependency for SCA. Water uptake and weight loss measurements were performed for the same immersion times used in the microhardness experiments. The different swelling/degradation behaviour presented by the blends was related to the respective variation in microhardness. Moreover, complementary characterization of the mechanical properties of SCA and SPCL was accomplished by dynamic mechanical analysis (DMA) and creep measurements. Microhardness measurements proved to be a useful technique for characterizing the mechanical behaviour near the surface of polymeric biomaterials, including in simulated physiological conditions

Biomimetic Ca-P coatings Incorporating bisphosphonates produced on starch-based degradable biomaterials

In this study, sodium clodronate, a well-known therapeutic agent from the family of bisphosphonates (BPs), is incorporated in a biomimetic calcium phosphate (CaP) coating, previously formed on the surface of a starch-based biomaterial by a sodium silicate methodology, as a strategy to develop a site-specific drug delivery system for bone tissue regeneration applications. The effects on the resulting CaP coatings were evaluated in terms of morphology, chemistry, and structure. The dissolution of Ca and P from the coating and the release profiles of sodium clodronate was also assessed. As a preliminary approach, this first study also aimed at evaluating the effects of this BP on the viability of a human osteoblastic cell line since there is still little information available on the interaction between BPs and this type of cells. Sodium clodronate was successfully incorporated, at different doses, in the structure of a biomimetic CaP layer previously formed by a sodium silicate process. This type of BPs had a stimulatory effect on osteoblastic activity, particularly at the specific concentration of 0.32 mg/mL. It is foreseen that these coatings can, for instances, be produced on the surface of degradable polymers and then used for regulating the equilibrium on osteoblastic/osteoclastic activity, leading to a controlled regenerative effect at the interface between the biomaterial and bone

Exome sequencing study in patients with multiple sclerosis reveals variants associated with disease course

BACKGROUND: It remains unclear whether disease course in multiple sclerosis (MS) is influenced by genetic polymorphisms. Here, we aimed to identify genetic variants associated with benign and aggressive disease courses in MS patients. METHODS: MS patients were classified into benign and aggressive phenotypes according to clinical criteria. We performed exome sequencing in a discovery cohort, which included 20 MS patients, 10 with benign and 10 with aggressive disease course, and genotyping in 2 independent validation cohorts. The first validation cohort encompassed 194 MS patients, 107 with benign and 87 with aggressive phenotypes. The second validation cohort comprised 257 patients, of whom 224 patients had benign phenotypes and 33 aggressive disease courses. Brain immunohistochemistries were performed using disease course associated genes antibodies. RESULTS: By means of single-nucleotide polymorphism (SNP) detection and comparison of allele frequencies between patients with benign and aggressive phenotypes, a total of 16 SNPs were selected for validation from the exome sequencing data in the discovery cohort. Meta-analysis of genotyping results in two validation cohorts revealed two polymorphisms, rs28469012 and rs10894768, significantly associated with disease course. SNP rs28469012 is located in CPXM2 (carboxypeptidase X, M14 family, member 2) and was associated with aggressive disease course (uncorrected p value < 0.05). SNP rs10894768, which is positioned in IGSF9B (immunoglobulin superfamily member 9B) was associated with benign phenotype (uncorrected p value < 0.05). In addition, a trend for association with benign phenotype was observed for a third SNP, rs10423927, in NLRP9 (NLR family pyrin domain containing 9). Brain immunohistochemistries in chronic active lesions from MS patients revealed expression of IGSF9B in astrocytes and macrophages/microglial cells, and expression of CPXM2 and NLRP9 restricted to brain macrophages/microglia. CONCLUSIONS: Genetic variants located in CPXM2, IGSF9B, and NLRP9 have the potential to modulate disease course in MS patients and may be used as disease activity biomarkers to identify patients with divergent disease courses. Altogether, the reported results from this study support the influence of genetic factors in MS disease course and may help to better understand the complex molecular mechanisms underlying disease pathogenesis

A Spatial Distribution Study of Faunal Remains from Two Lower Magdalenian Occupation Levels in El Mirón Cave, Cantabria, Spain

Abstract: Human behaviour can be reconstructed by analysing specific activities and campsite organization using spatial analysis. The dense occupation layers of the Lower Cantabrian Magdalenian in the Northern Spain reveal varied aspects of Upper Palaeolithic lifeways, including evidence of specific localized activities. The outer vestibule of El Mirón cave has a particularly rich and intact Lower Magdalenian occupation horizon, Levels 15–17. The excavations in the outer vestibule “Cabin” area of the site revealed excellent bone preservation. Artefacts and faunal remains were individually recorded and sediments water-screened to yield a large sample of archaeological finds and spatial data. Zooarchaeological analysis provided the taxonomic, anatomic and taphonomic determination of the faunal individual finds. Smaller animal remains were categorized and counted; special attention was given to the identification of anthropogenic modifications such as burnt bones or bone flakes. These small refuse items are considered to be useful, in situ indicators of localized activities. The spatial distribution analysis of this dense and complex palimpsest of El Mirón Lower Cantabrian Magdalenian layers required GIS based methods including density analysis, heatmaps and cluster analysis. Based on the spatial distribution of Level 15 and 16 faunal remains, different activity areas were identified comprising hearth, working and dropping zones. These results imply the deliberately segregated use of space within the Lower Cantabrian Magdalenian site area, in which bone-processing activities played a central rol

Pantropical variability in tree crown allometry

Aim: Tree crowns determine light interception, carbon and water exchange. Thus, understanding the factors causing tree crown allometry to vary at the tree and stand level matters greatly for the development of future vegetation modelling and for the calibration of remote sensing products. Nevertheless, we know little about large‐scale variation and determinants in tropical tree crown allometry. In this study, we explored the continental variation in scaling exponents of site‐specific crown allometry and assessed their relationships with environmental and stand‐level variables in the tropics. / Location: Global tropics. / Time period: Early 21st century. / Major taxa studied: Woody plants. / Methods: Using a dataset of 87,737 trees distributed among 245 forest and savanna sites across the tropics, we fitted site‐specific allometric relationships between crown dimensions (crown depth, diameter and volume) and stem diameter using power‐law models. Stand‐level and environmental drivers of crown allometric relationships were assessed at pantropical and continental scales. / Results: The scaling exponents of allometric relationships between stem diameter and crown dimensions were higher in savannas than in forests. We identified that continental crown models were better than pantropical crown models and that continental differences in crown allometric relationships were driven by both stand‐level (wood density) and environmental (precipitation, cation exchange capacity and soil texture) variables for both tropical biomes. For a given diameter, forest trees from Asia and savanna trees from Australia had smaller crown dimensions than trees in Africa and America, with crown volumes for some Asian forest trees being smaller than those of trees in African forests. / Main conclusions: Our results provide new insight into geographical variability, with large continental differences in tropical tree crown allometry that were driven by stand‐level and environmental variables. They have implications for the assessment of ecosystem function and for the monitoring of woody biomass by remote sensing techniques in the global tropics

Tree height integrated into pantropical forest biomass estimates

Copyright © 2012 European Geosciences Union. This is the published version available at http://www.biogeosciences.net/9/3381/2012/bg-9-3381-2012.htmlAboveground tropical tree biomass and carbon storage estimates commonly ignore tree height (H). We estimate the effect of incorporating H on tropics-wide forest biomass estimates in 327 plots across four continents using 42 656 H and diameter measurements and harvested trees from 20 sites to answer the following questions: 1. What is the best H-model form and geographic unit to include in biomass models to minimise site-level uncertainty in estimates of destructive biomass? 2. To what extent does including H estimates derived in (1) reduce uncertainty in biomass estimates across all 327 plots? 3. What effect does accounting for H have on plot- and continental-scale forest biomass estimates? The mean relative error in biomass estimates of destructively harvested trees when including H (mean 0.06), was half that when excluding H (mean 0.13). Power- and Weibull-H models provided the greatest reduction in uncertainty, with regional Weibull-H models preferred because they reduce uncertainty in smaller-diameter classes (≤40 cm D) that store about one-third of biomass per hectare in most forests. Propagating the relationships from destructively harvested tree biomass to each of the 327 plots from across the tropics shows that including H reduces errors from 41.8 Mg ha−1 (range 6.6 to 112.4) to 8.0 Mg ha−1 (−2.5 to 23.0). For all plots, aboveground live biomass was −52.2 Mg ha−1 (−82.0 to −20.3 bootstrapped 95% CI), or 13%, lower when including H estimates, with the greatest relative reductions in estimated biomass in forests of the Brazilian Shield, east Africa, and Australia, and relatively little change in the Guiana Shield, central Africa and southeast Asia. Appreciably different stand structure was observed among regions across the tropical continents, with some storing significantly more biomass in small diameter stems, which affects selection of the best height models to reduce uncertainty and biomass reductions due to H. After accounting for variation in H, total biomass per hectare is greatest in Australia, the Guiana Shield, Asia, central and east Africa, and lowest in east-central Amazonia, W. Africa, W. Amazonia, and the Brazilian Shield (descending order). Thus, if tropical forests span 1668 million km2 and store 285 Pg C (estimate including H), then applying our regional relationships implies that carbon storage is overestimated by 35 Pg C (31–39 bootstrapped 95% CI) if H is ignored, assuming that the sampled plots are an unbiased statistical representation of all tropical forest in terms of biomass and height factors. Our results show that tree H is an important allometric factor that needs to be included in future forest biomass estimates to reduce error in estimates of tropical carbon stocks and emissions due to deforestation

Consensus statement on the use of alemtuzumab in daily clinical practice in Spain

Introducción: Alemtuzumab es un fármaco de alta eficacia aprobado por la Agencia Europeade Medicamentos como tratamiento modificador de la enfermedad en pacientes con esclerosismúltiple remitente recurrente.Objetivo: Elaborar un documento de consenso sobre el manejo de alemtuzumab en la práctica clínica habitual, que sea de aplicación en el ámbito español.Desarrollo: Un grupo de expertos en esclerosis múltiple revisó las publicaciones disponibles hasta diciembre de 2017, de tratamiento con alemtuzumab y esclerosis múltiple. Se incluyeron trabajos sobre eficacia, efectividad y seguridad, despistaje de infecciones y vacunación, admi-nistración y monitorización. La propuesta inicial de recomendaciones fue desarrollada por un grupo coordinador con base en la evidencia disponible y en su experiencia clínica. El proceso de consenso se llevó a cabo en 2 etapas; se estableció como porcentaje inicial de acuerdo grupal el 80%. El documento final con todas las recomendaciones acordadas por el grupo de trabajo se sometió a revisión externa y los comentarios recibidos fueron considerados por el grupo coordinador. Conclusiones: El documento aportado pretende ser una herramienta útil para facilitar el manejo del fármaco en condiciones de práctica clínica habitualtIntroduction: Alemtuzumab is a highly effective drug approved by the European Medicines Agency as a disease-modifying drug for the treatment of relapsing-remitting multiple sclerosis. Objective: A consensus document was drafted on the management of alemtuzumab in routineclinical practice in Spain. Development: A group of multiple sclerosis specialists reviewed articles addressing treatment with alemtuzumab in patients with multiple sclerosis and published before December 2017. The included studies assessed the drug’s efficacy, effectiveness, and safety; screening for infections and vaccination; and administration and monitoring aspects. The initial proposed recommendations were developed by a coordinating group and based on the available evidence and their clinical experience. The consensus process was carried out in 2 stages, with the initial threshold percentage for group agreement established at 80%. The final document with all the recom-mendations agreed by the working group was submitted for external review and the comments received were considered by the coordinating group. Conclusion: The present document is intended to be used as a tool for optimising the management of alemtuzumab in routine clinical practiceLa elaboración de este manuscrito ha sido financiada por Sanofi-Genzym

Consenso de expertos sobre el uso de alemtuzumab en la práctica clínica diaria en España

Introducción: Alemtuzumab es un fármaco de alta eficacia aprobado por la Agencia Europea de Medicamentos como tratamiento modificador de la enfermedad en pacientes con esclerosis múltiple remitente recurrente. Objetivo: Elaborar un documento de consenso sobre el manejo de alemtuzumab en la práctica clínica habitual, que sea de aplicación en el ámbito español. Desarrollo: Un grupo de expertos en esclerosis múltiple revisó las publicaciones disponibles hasta diciembre de 2017, de tratamiento con alemtuzumab y esclerosis múltiple. Se incluyeron trabajos sobre eficacia, efectividad y seguridad, despistaje de infecciones y vacunación, administración y monitorización. La propuesta inicial de recomendaciones fue desarrollada por un grupo coordinador con base en la evidencia disponible y en su experiencia clínica. El proceso de consenso se llevó a cabo en 2 etapas; se estableció como porcentaje inicial de acuerdo grupal el 80%. El documento final con todas las recomendaciones acordadas por el grupo de trabajo se sometió a revisión externa y los comentarios recibidos fueron considerados por el grupo coordinador. Conclusiones: El documento aportado pretende ser una herramienta útil para facilitar el manejo del fármaco en condiciones de práctica clínica habitual.Introduction: Alemtuzumab is a highly effective drug approved by the European Medicines Agency as a disease-modifying drug for the treatment of relapsing-remitting multiple sclerosis. Objective: A consensus document was drafted on the management of alemtuzumab in routine clinical practice in Spain. Development: A group of multiple sclerosis specialists reviewed articles addressing treatment with alemtuzumab in patients with multiple sclerosis and published before December 2017. The included studies assessed the drug's efficacy, effectiveness, and safety; screening for infections and vaccination; and administration and monitoring aspects. The initial proposed recommendations were developed by a coordinating group and based on the available evidence and their clinical experience. The consensus process was carried out in 2 stages, with the initial threshold percentage for group agreement established at 80%. The final document with all the recommendations agreed by the working group was submitted for external review and the comments received were considered by the coordinating group. Conclusion: The present document is intended to be used as a tool for optimising the management of alemtuzumab in routine clinical practice

Pantropical variability in tree crown allometry

Aim Tree crowns determine light interception, carbon and water exchange. Thus, understanding the factors causing tree crown allometry to vary at the tree and stand level matters greatly for the development of future vegetation modelling and for the calibration of remote sensing products. Nevertheless, we know little about large‐scale variation and determinants in tropical tree crown allometry. In this study, we explored the continental variation in scaling exponents of site‐specific crown allometry and assessed their relationships with environmental and stand‐level variables in the tropics. Location Global tropics. Time period Early 21st century. Major taxa studied Woody plants. Methods Using a dataset of 87,737 trees distributed among 245 forest and savanna sites across the tropics, we fitted site‐specific allometric relationships between crown dimensions (crown depth, diameter and volume) and stem diameter using power‐law models. Stand‐level and environmental drivers of crown allometric relationships were assessed at pantropical and continental scales. Results The scaling exponents of allometric relationships between stem diameter and crown dimensions were higher in savannas than in forests. We identified that continental crown models were better than pantropical crown models and that continental differences in crown allometric relationships were driven by both stand‐level (wood density) and environmental (precipitation, cation exchange capacity and soil texture) variables for both tropical biomes. For a given diameter, forest trees from Asia and savanna trees from Australia had smaller crown dimensions than trees in Africa and America, with crown volumes for some Asian forest trees being smaller than those of trees in African forests. Main conclusions Our results provide new insight into geographical variability, with large continental differences in tropical tree crown allometry that were driven by stand‐level and environmental variables. They have implications for the assessment of ecosystem function and for the monitoring of woody biomass by remote sensing techniques in the global tropics