Rites of Passage as a Framework for Community Interventions with Youth

This article discusses the potential value of adopting a rites of passage framework for developing community interventions for youth and suggests principles for its application. We propose a contemporary working definition of the concept, how it could reshape the way we approach community and youth development, and 20 core components of a rites of passage process developed from our work experience spanning over 40 years

Rites of Passage as a Framework for Community Interventions with Youth

This article discusses the potential value of adopting a rites of passage framework for developing community interventions for youth and suggests principles for its application. We propose a contemporary working definition of the concept, how it could reshape the way we approach community and youth development, and 20 core components of a rites of passage process developed from our work experience spanning over 40 years

In vivo T1ρ and T2 mapping of articular cartilage in osteoarthritis of the knee using 3T MRI

SummaryObjectiveEvaluation and treatment of patients with early stages of osteoarthritis (OA) is dependent upon an accurate assessment of the cartilage lesions. However, standard cartilage dedicated magnetic resonance (MR) techniques are inconclusive in quantifying early degenerative changes. The objective of this study was to determine the ability of MR T1rho (T1ρ) and T2 mapping to detect cartilage matrix degeneration between normal and early OA patients.MethodSixteen healthy volunteers (mean age 41.3) without clinical or radiological evidence of OA and 10 patients (mean age 55.9) with OA were scanned using a 3Tesla (3T) MR scanner. Cartilage volume and thickness, and T1ρ and T2 values were compared between normal and OA patients. The relationship between T1ρ and T2 values, and Kellgren–Lawrence scores based on plain radiographs and the cartilage lesion grading based on MR images were studied.ResultsThe average T1ρ and T2 values were significantly increased in OA patients compared with controls (52.04±2.97ms vs 45.53±3.28ms with P=0.0002 for T1ρ, and 39.63±2.69ms vs 34.74±2.48ms with P=0.001 for T2). Increased T1ρ and T2 values were correlated with increased severity in radiographic and MR grading of OA. T1ρ has a larger range and higher effect size than T2, 3.7 vs 3.0.ConclusionOur results suggest that both in vivo T1ρ and T2 relaxation times increase with the degree of cartilage degeneration. T1ρ relaxation time may be a more sensitive indicator for early cartilage degeneration than T2. The ability to detect early cartilage degeneration prior to morphologic changes may allow us to critically monitor the course of OA and injury progression, and to evaluate the success of treatment to patients with early stages of OA

MRI texture analysis of subchondral bone at the tibial plateau

OBJECTIVES: To determine the feasibility of MRI texture analysis as a method of quantifying subchondral bone architecture in knee osteoarthritis (OA).   METHODS: Asymptomatic subjects aged 20-30 (group 1, n = 10), symptomatic patients aged 40-50 (group 2, n = 10) and patients scheduled for knee replacement aged 55-85 (group 3, n = 10) underwent high spatial resolution T1-weighted coronal 3T knee MRI. Regions of interest were created in the medial (MT) and lateral (LT) tibial subchondral bone from which 20 texture parameters were calculated. T2 mapping of the tibial cartilage was performed in groups 1 and 2. Mean parameter values were compared between groups using ANOVA. Linear discriminant analysis (LDA) was used to evaluate the ability of texture analysis to classify subjects correctly.   RESULTS: Significant differences in 18/20 and 12/20 subchondral bone texture parameters were demonstrated between groups at the MT and LT respectively. There was no significant difference in mean MT or LT cartilage T2 values between group 1 and group 2. LDA demonstrated subject classification accuracy of 97 % (95 % CI 91-100 %).   CONCLUSION: MRI texture analysis of tibial subchondral bone may allow detection of alteration in subchondral bone architecture in OA. This has potential applications in understanding OA pathogenesis and assessing response to treatment.   KEY POINTS: • Improved techniques to monitor OA disease progression and treatment response are desirable • Subchondral bone (SB) may play significant role in the development of OA • MRI texture analysis is a method of quantifying changes in SB architecture • Pilot study showed that this technique is feasible and reliable • Significant differences in SB texture were demonstrated between individuals with/without OA

Laser-induced modification of the patellar ligament tissue: comparative study of structural and optical changes

The effects of non-ablative infrared (IR) laser treatment of collagenous tissue have been commonly interpreted in terms of collagen denaturation spread over the laser-heated tissue area. In this work, the existing model is refined to account for the recently reported laser-treated tissue heterogeneity and complex collagen degradation pattern using comprehensive optical imaging and calorimetry toolkits. Patella ligament (PL) provided a simple model of type I collagen tissue containing its full structural content from triple-helix molecules to gross architecture. PL ex vivo was subjected to IR laser treatments (laser spot, 1.6 mm) of equal dose, where the tissue temperature reached the collagen denaturation temperature of 60 ± 2°C at the laser spot epicenterin the first regime, and was limited to 67 ± 2°C in the second regime. The collagen network was analyzed versus distance from the epicenter. Experimental characterization of the collagenous tissue at all structural levels included cross-polarization optical coherence tomography, nonlinear optical microscopy, light microscopy/histology, and differential scanning calorimetry. Regressive rearrangement of the PL collagen network was found to spread well outside the laser spot epicenter (>2 mm) and was accompanied by multilevel hierarchical reorganization of collagen. Four zones of distinct optical and morphological properties were identified, all elliptical in shape, and elongated in the direction perpendicular to the PL long axis. Although the collagen transformation into a random-coil molecular structure was occasionally observed, it was mechanical integrity of the supramolecular structures that was primarily compromised. We found that the structural rearrangement of the collagen network related primarily to the heat-induced thermo-mechanical effects rather than molecular unfolding. The current body of evidence supports the notion that the supramolecular collagen structure suffered degradation of various degrees, which gave rise to the observed zonal character of the laser-treated lesion

Fractionation of eucalyptus globulus wood by glycerol-water pretreatment: optimization and modeling

A glycerol-organosolv process can be a good alternative for Eucalyptus wood fractionation into its main compounds, improving the enzymatic saccharification of the cellulose. A study of process variables - glycerol−water percent content, temperature, and process time - was carried out using a Box-Behnken experimental design. The cellulose obtained from pretreated solids was recovered almost quantitatively, leading to a solid with a high percentage of cellulose (77 g/100 g of pretreated solid), low lignin content (9 g/100 g of pretreated solid), and 18% of residual hemicellulose in the solid at 200 °C, 56% of glycerol−water and 69 min. The enzymatic saccharification was enhanced achieving 98% cellulose-to-glucose conversion (under conditions: liquid to solid ratio 20 g/g and enzyme loading 20 FPU/g of solid). This study contributes to the improvement of biomass fractionation by exploring an eco-friendly treatment which allows for almost complete wood fractionation into constituents and high levels of glucose recovery available for subsequent yeast fermentation to bioethanol.The authors A. Romani and F. B. Pereira thank to the Portuguese Foundation for Science and Technology (FCT, Portugal) for their fellowships (grant number: SFRH/BPD/77995/2011 and SFRH/BD/64776/2009, respectively)

The Major Surface-Associated Saccharides of Klebsiella pneumoniae Contribute to Host Cell Association

Analysing the pathogenic mechanisms of a bacterium requires an understanding of the composition of the bacterial cell surface. The bacterial surface provides the first barrier against innate immune mechanisms as well as mediating attachment to cells/surfaces to resist clearance. We utilised a series of Klebsiella pneumoniae mutants in which the two major polysaccharide layers, capsule and lipopolysaccharide (LPS), were absent or truncated, to investigate the ability of these layers to protect against innate immune mechanisms and to associate with eukaryotic cells. The capsule alone was found to be essential for resistance to complement mediated killing while both capsule and LPS were involved in cell-association, albeit through different mechanisms. The capsule impeded cell-association while the LPS saccharides increased cell-association in a non-specific manner. The electrohydrodynamic characteristics of the strains suggested the differing interaction of each bacterial strain with eukaryotic cells could be partly explained by the charge density displayed by the outermost polysaccharide layer. This highlights the importance of considering not only specific adhesin:ligand interactions commonly studied in adherence assays but also the initial non-specific interactions governed largely by the electrostatic interaction forces

Enumeration of Functional T-Cell Subsets by Fluorescence-Immunospot Defines Signatures of Pathogen Burden in Tuberculosis

IFN-γ and IL-2 cytokine-profiles define three functional T-cell subsets which may correlate with pathogen load in chronic intracellular infections. We therefore investigated the feasibility of the immunospot platform to rapidly enumerate T-cell subsets by single-cell IFN-γ/IL-2 cytokine-profiling and establish whether immunospot-based T-cell signatures distinguish different clinical stages of human tuberculosis infection.We used fluorophore-labelled anti-IFN-γ and anti-IL-2 antibodies with digital overlay of spatially-mapped colour-filtered images to enumerate dual and single cytokine-secreting M. tuberculosis antigen-specific T-cells in tuberculosis patients and in latent tuberculosis infection (LTBI). We validated results against established measures of cytokine-secreting T-cells.Fluorescence-immunospot correlated closely with single-cytokine enzyme-linked-immunospot for IFN-γ-secreting T-cells and IL-2-secreting T-cells and flow-cytometry-based detection of dual IFN-γ/IL-2-secreting T-cells. The untreated tuberculosis signature was dominated by IFN-γ-only-secreting T-cells which shifted consistently in longitudinally-followed patients during treatment to a signature dominated by dual IFN-γ/IL-2-secreting T-cells in treated patients. The LTBI signature differed from active tuberculosis, with higher proportions of IL-2-only and IFN-γ/IL-2-secreting T-cells and lower proportions of IFN-γ-only-secreting T-cells.Fluorescence-immunospot is a quantitative, accurate measure of functional T-cell subsets; identification of cytokine-signatures of pathogen burden, distinct clinical stages of M. tuberculosis infection and long-term immune containment suggests application for treatment monitoring and vaccine evaluation