Inactivation of α2-Macroglobulin by Activated Human Polymorphonuclear Leukocytes

The proteolytic activity of trypsin releases the dye Remazol Brilliant Blue from its high molecular weight substrate, the skin powder (Hide Powder Azure, Sigma), with an increase in absorbance at 595 nm. Active α2- macroglobulin (80 μg/ml) totally inhibits the proteolytic activity of trypsin (14 μg/ml) by trapping this protease. But after a 20 min incubation of α2-macroglobulin at 37°C with 2 × 106 human polymorphonuclear leukocytes activated by N-formyl-L-methionyl-L-leucyl-L-phenylalanine (10−7 M) and cytochalasin B (10−8 M), 100% of trypsin activity was recovered, indicating a total inactivation of α2-macroglobuHn. Incubation with granulocyte myeloperoxidase also inactivates α2-macroglobulin. Hypochlorous acid, a by-product of myeloperoxidase activity, at a concentration of 10−7 M also inactivates α2-macroglobulin, which indicates that an important cause of α2-macroglobulin inactivation by activated polymorphonuclear leukocytes could be the activity of myeloperoxidase

Isokinetic evaluation of knee muscles in soccer players: discriminant analysis [Avaliação isocinética dos músculos do joelho em jogadores de futebol: análise discriminante]; [Evaluación isocinética de los músculos de la rodilla en jugadores de fútbol: análisis discriminante]

Introduction: Muscle activity in soccer players can be measured by isokinetic dynamometer, which is a reliable tool for assessing human performance. Objectives: To perform isokinetic analyses and to determine which variables differentiate the under-17 (U17) soccer category from the professional (PRO). Methods: Thirty four players were assessed (n=17 for each category). The isokinetic variables used for the knee extension-flexion analysis were: peak torque (Nm), total work (J), average power (W), angle of peak torque (deg.), agonist/ antagonist ratio (%), measured for three velocities (60°/s, 120°/s and 300°/s), with each series containing five repetitions. Three Wilks' Lambda discriminant analyses were performed, to identify which variables were more significant for the definition of each of the categories. Results: The discriminative variables at 60°/s in the PRO category were: extension peak torque, flexion total work, extension average power and agonist/antagonist ratio; and for the U17s were: extension total work, flexion peak torque and flexion average power. At 120°/s for the PRO category the discriminant variables were: flexion peak torque and extension average power; for the U17s they were: extension total work and flexion average power. Finally at 300°/s, the variables found in the PRO and U17 categories respectively were: extension average power and extension total work. Conclusion: Isokinetic variables for flexion and extension knee muscles were able to significantly discriminate between PRO and U17 soccer players. RESUMO Introdução: A atividade muscular em jogadores de futebol pode ser medida por meio do dinamômetro isocinético, que é um instrumento confiável para avaliação do desempenho humano. Objetivos: Conduzir análises isocinéticas e discriminar quais variáveis diferenciam a categoria sub-17 (S17) da profissional (PRO). Métodos: Trinta e quatro jogadores de futebol (n=17 para cada categoria) foram avaliados. As variáveis isocinéticas utilizadas para a análise de extensão-flexão do joelho foram: pico de torque (Nm), trabalho total (J), potência média (W), ângulo de pico de torque (graus), razão agonista/antagonista (%), testadas em três velocidades (60°/s, 120°/s e 300°/s), com cada série contendo cinco repetições. Três análises discriminantes foram feitas usando o método Wilk's Lambda para identificar quais variáveis fariam uma discriminação significativa entre as duas categorias. Resultados: As variáveis discriminantes a 60°/s na categoria PRO foram: pico de torque extensores, trabalho total flexores, potência média de extensores e razão agonista/antagonista; e para os S17 foram: trabalho total de extensores, pico de torque de flexores e potência média de flexores. A 120°/s para a categoria PRO as variáveis discriminantes foram: pico de torque de flexores e potência média de extensores; para os S17 foram: trabalho total de extensores e potência média de flexores. A 300°/s, as variáveis encontradas para as categorias PRO e S17 foram, respectivamente: potência média de extensores e trabalho total de extensores. Conclusão: As variáveis isocinéticas para os músculos do joelho flexores e extensores foram capazes de fazer uma discriminação significativa entre jogadores de futebol PRO e S17. RESUMEN Introducción: La actividad muscular en jugadores de fútbol puede ser medida por medio del dinamómetro isocinético, que es un instrumento confiable para evaluación del desempeño humano. Objetivos: Conducir análisis isocinéticos y discriminar qué variables diferencian la categoría sub-17 (S17) de la profesional (PRO). Métodos: Fueron evaluados treinta y cuatro jugadores de fútbol (n=17 para cada categoría). Las variables isocinéticas utilizadas para el análisis de extensión-flexión de la rodilla fueron: pico de torque (Nm), trabajo total (J), potencia media (W), ángulo de pico de torque (grados), razón agonista/antagonista (%), probadas en tres velocidades (60°/s, 120°/s y 300°/s), con cada serie conteniendo cinco repeticiones. Fueron realizados tres análisis discriminantes usando el método Wilk's Lambda para identificar qué variables harían una discriminación significativa entre las dos categorías. Resultados: Las variables discriminantes a 60°/s en la categoría PRO fueron: pico de torque extensores, trabajo total flexores, potencia media de extensores y razón agonista/antagonista; y para los S17 fueron: trabajo total de extensores, pico de torque de flexores y potencia media de flexores. A 120°/s para la categoría PRO las variables discriminantes fueron: pico de torque de flexores y potencia media de extensores; para los S17 fueron: trabajo total de extensores y potencia media de flexores. A 300°/s, las variables encontradas para las categorías PRO y S17 fueron, respectivamente: potencia media de extensores y trabajo total de extensores. Conclusión: Las variables isocinéticas para los músculos de la rodilla flexores y extensores fueron capaces de hacer una discriminación significativa entre jugadores de fútbol PRO y S17

Bioactivity, biocompatibility and antimicrobial properties of a chitosan-mineral composite for periodontal tissue regeneration

A composite membrane of the polymer, chitosan, and the silver-exchanged mineral phase, tobermorite, was prepared by solvent casting and characterised by scanning electron microscopy and Fourier transform infrared spectroscopy. The in vitro bioactivity, cytocompatibility and antimicrobial activity of the composite were evaluated with respect to its potential application as a guided tissue regeneration (GTR) membrane. The in vitro bioactivity was verified by the formation of hydroxyapatite on the surface of the membrane in simulated body fluid and its cytocompatibility was established using MG63 human osteosarcoma cells. The presence of silver ions conferred significant antimicrobial activity against S. aureus, P. aeruginosa and E. coli. The findings of this investigation have indicated that the chitosansilver-tobermorite composite is a prospective candidate for GTR applications

Supramolecular thermoplastics and thermoplastic elastomer materials with self-healing ability based on oligomeric charged triblock copolymers

Supramolecular polymeric materials constitute a unique class of materials held together by non-covalent interactions. These dynamic supramolecular interactions can provide unique properties such as a strong decrease in viscosity upon relatively mild heating, as well as self-healing ability. In this study we demonstrate the unique mechanical properties of phase-separated electrostatic supramolecular materials based on mixing of low molar mass, oligomeric, ABA-triblock copolyacrylates with oppositely charged outer blocks. In case of well-chosen mixtures and block lengths, the charged blocks are phase separated from the uncharged matrix in a hexagonally packed nanomorphology as observed by transmission electron microscopy. Thermal and mechanical analysis of the material shows that the charged sections have a T-g closely beyond room temperature, whereas the material shows an elastic response at temperatures far above this T-g ascribed to the electrostatic supramolecular interactions. A broad set of materials having systematic variations in triblock copolymer structures was used to provide insights in the mechanical properties and and self-healing ability in correlation with the nanomorphology of the materials

Atomic force microscopy based nanoassay: A new method to study \u3b1-Synuclein-dopamine bioaffinity interactions

Intrinsically Disordered Proteins (IDPs) are characterized by the lack of well-defined 3-D structure and show high conformational plasticity. For this reason, they are a strong challenge for the traditional characterization of structure, supramolecular assembly and biorecognition phenomena. We show here how the fine tuning of protein orientation on a surface turns useful in the reliable testing of biorecognition interactions of IDPs, in particular \u3b1-Synuclein. We exploited atomic force microscopy (AFM) for the selective, nanoscale confinement of \u3b1-Synuclein on gold to study the early stages of \u3b1-Synuclein aggregation and the effect of small molecules, like dopamine, on the aggregation process. Capitalizing on the high sensitivity of AFM topographic height measurements we determined, for the first time in the literature, the dissociation constant of dopamine-\u3b1-Synuclein adducts

Assessment of Skeletal Muscle Contractile Properties by Radial Displacement: The Case for Tensiomyography

Skeletal muscle operates as a near-constant volume system; as such muscle shortening during contraction is transversely linked to radial deformation. Therefore, to assess contractile properties of skeletal muscle, radial displacement can be evoked and measured. Mechanomyography measures muscle radial displacement and during the last 20 years, tensiomyography has become the most commonly used and widely reported technique among the various methodologies of mechanomyography. Tensiomyography has been demonstrated to reliably measure peak radial displacement during evoked muscle twitch, as well as muscle twitch speed. A number of parameters can be extracted from the tensiomyography displacement/time curve and the most commonly used and reliable appear to be peak radial displacement and contraction time. The latter has been described as a valid non-invasive means of characterising skeletal muscle, based on fibre-type composition. Over recent years, applications of tensiomyography measurement within sport and exercise have appeared, with applications relating to injury, recovery and performance. Within the present review, we evaluate the perceived strengths and weaknesses of tensiomyography with regard to its efficacy within applied sports medicine settings. We also highlight future tensiomyography areas that require further investigation. Therefore, the purpose of this review is to critically examine the existing evidence surrounding tensiomyography as a tool within the field of sports medicine

Biocompatible polymeric microparticles produced by a simple biomimetic approach

The use of superhydrophobic surfaces to produce polymeric particles proves to be biologically friendly since it entails the pipetting and subsequent cross-linking of polymeric solutions under mild experimental conditions. Moreover, it renders encapsulation efficiencies of ∼100%. However, the obtained particles are 1 to 2 mm in size, hindering to a large extent their application in clinical trials. Improving on this technique, we propose the fabrication of polymeric microparticles by spraying a hydrogel precursor over superhydrophobic surfaces followed by photo-cross-linking. The particles were produced from methacrylamide chitosan (MA-CH) and characterized in terms of their size and morphology. As demonstrated by optical and fluorescence microscopy, spraying followed by photo-cross-linking led, for the first time, to the production of spherical particles with diameters on the order of micrometers, nominal sizes not attainable by pipetting. Particles such as these are suitable for medical applications such as drug delivery and tissue engineering.We thank Ivo Aroso and Ana Isabel Neto for their valuable support with FTIR and compression experiments, respectively. A.M.S.C. thanks FCT for financial support through grant BIM/PTDC/CTM-BPC/112774/2009_02. M.A.-M. thanks CONACyT (Mexico) for financial support through post-doc grant no. 203732. N.M.O. thanks FCT for financial support through Ph.D. scholarship no. SFRH/BD/73172/2010. This work was funded by the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. REGPOT-CT2012-316331-POLARIS, by FEDER through the Competitive Factors Operation Program-COMPETE, and by national funds through FCT - Fundacao para a Ciencia e a Tecnologia in the scope of project PTDC/CTM-BIO/1814/2012

A descriptive study of a manual therapy intervention within a randomised controlled trial for hamstring and lower limb injury prevention

The journal has been informed by its publisher BioMed Central that contrary to the statement in this article [Wayne Hoskins, Henry Pollard, Chiropractic & Osteopathy 2010, 18:23], they have been advised by the authors' institution Macquarie University, that its Human Research Ethics Committee did not approve this study. Because the study was conducted without institutional ethics committee approval it has been retracted