Interference with glycosaminoglycan-chemokine interactions with a probe to alter leukocyte recruitment and inflammation in vivo

In vivo leukocyte recruitment is not fully understood and may result from interactions of chemokines with glycosaminoglycans/GAGs. We previously showed that chlorite-oxidized oxyamylose/COAM binds the neutrophil chemokine GCP-2/CXCL6. Here, mouse chemokine binding by COAM was studied systematically and binding affinities of chemokines to COAM versus GAGs were compared. COAM and heparan sulphate bound the mouse CXC chemokines KC/CXCL1, MIP-2/CXCL2, IP-10/CXCL10 and I-TAC/CXCL11 and the CC chemokine RANTES/CCL5 with affinities in the nanomolar range, whereas no binding interactions were observed for mouse MCP-1/CCL2, MIP-1α/CCL3 and MIP-1β/CCL4. The affinities of COAM-interacting chemokines were similar to or higher than those observed for heparan sulphate. Although COAM did not display chemotactic activity by itself, its co-administration with mouse GCP-2/CXCL6 and MIP-2/CXCL2 or its binding of endogenous chemokines resulted in fast and cooperative peritoneal neutrophil recruitment and in extravasation into the cremaster muscle in vivo. These local GAG mimetic features by COAM within tissues superseded systemic effects and were sufficient and applicable to reduce LPS-induced liver-specific neutrophil recruitment and activation. COAM mimics glycosaminoglycans and is a nontoxic probe for the study of leukocyte recruitment and inflammation in vivo

The overall effects of end-of-course assessment on student performance: A comparison between multiple choice testing, peer assessment, case-based assessment and portfolio assessment

This study investigates the effect of method of assessment on student performance. Five research conditions go together with one of four assessment modes, namely: portfolio, case-based, peer assessment, and multiple choice evaluation. Data collection is done by means of a pre-test/post-test-design with the help of two standardised tests (N=816). Results show that assessment method does make a difference: assessments do not produce overall effects on student performance. Moreover, student-activating instruction efforts do not automatically result in more extensive learning gains. Finally, test results show, when compared to other assessments, a statistically significant positive effect of the multiple choice test on students' test scores. However, students' preparation level and the closed book format of the tests might serve explanatory purposes.01status: publishe

Towards an equilibrium model for creating powerful learning environments. Validation of a questionnaire on creating powerful learning environments during teacher training internships

Recently, many insights have been gained into how to create powerful learning environments. The goal of learning how to teach in this way has important consequences for teacher training. Firstly, scholars indicate the necessity to work out a theoretical framework for the student-teachers which is sufficiently complete, but still manageable, and which is operationalised into concrete educational approaches. The current article presents such a framework, based on a literature study. Key teaching activities were described by means of 13 dimensions. Aiming at a gradually more complex model for use in teacher education, these dimensions were summarized in a model with four interconnected main dimensions. Possible conflicts between the instructional activities of the four main dimensions were indicated. Teachers have to search for appropriate balances within these dilemmas. The whole is conceptualized as an "equilibrium model for creating powerful learning environments". Secondly, based on this framework, instruments could be constructed which facilitate research into approaches within teacher training which encourage learning how to teach in this way. A questionnaire to evaluate the degree of creating powerful learning environments during internships was, therefore, constructed and validated. Analyses indicate a suitable degree of reliability and validity. Furthermore, a confirmatory factor analysis indicates that the assumed theoretical structure was reflected by the experimental data. (Contains 5 tables and 3 notes.)01status: publishe

De effecten van de evaluatie-ervaring op de percepties van studenten over assessment

Deze studie onderzoekt de effecten van de concrete ervaring met een ongekende evaluatievorm op de percepties van studenten ten aanzien van deze evaluatievorm en ‘assessment’. Daartoe werd een cursus Ontwikkelings-psychologie ingericht waarbij vier evaluatievormen – namelijk een meerkeuzetoets, een casusexamen, een ‘peer assessment’ en een portfolio – werden toegekend aan vijf onderzoeksgroepen (N= 612). Data werden verzameld via een ‘pretest-posttest design’ met vragenlijsten. De resultaten tonen aan dat onbekende evaluatievormen aanvankelijk onbemind zijn. Onzekerheid over de procedure en de invloed op de prestaties leidt tot een kritische, weerhoudende attitude. Niettegenstaande ondervindt elke evaluatievorm na het examen een toename van positieve percepties, evenals verwante evaluatievormen. De proportionele toename verschilt echter van methode tot methode. Hoe positiever de ervaringen met de evaluatievorm, des te hoger is de toename van positieve percepties. Het nastreven van positieve ervaringen, zelfs met ongekende evaluatievormen, lijkt bijgevolg een aangewezen innovatiestrategie.01status: publishe

Educating for learning-focused teaching in teacher training: The need to link learning content with practice experiences within an inductive approach

Recently, many insights have been gained into the design of powerful learning environments. Teacher training must take account of this knowledge when educating the teachers of the future. This study investigates possible approaches within teacher training which could encourage student teachers towards learning-focused teaching activities. The main question is whether students from institutions where these activities were taught in a more inductive way pay more attention to these aspects during teaching practice than those from other institutions. This inductive approach is concretized by the following: (a) modelling of these teaching activities by the teacher trainers; (b) coaching the teaching practice experiences and giving hints; (c) taking the students' learning experiences as starting points for reflection. Three existing teacher-training institutions were chosen to provide different and ecologically valid settings in a feasible way. Comparisons of the institutional approaches with the approaches during teaching practice confirm the importance of an inductive approach in which different practice experiences, systematically aimed at making the students restructure their conceptual frameworks of learning and instruction, are used for reflection. (c) 2006 Elsevier Ltd. All rights reserved.status: publishe

Interference with glycosaminoglycan-chemokine interactions with a probe to alter leukocyte recruitment and inflammation in vivo

In vivo leukocyte recruitment is not fully understood and may result from interactions of chemokines with glycosaminoglycans/GAGs. We previously showed that chlorite-oxidized oxyamylose/COAM binds the neutrophil chemokine GCP-2/CXCL6. Here, mouse chemokine binding by COAM was studied systematically and binding affinities of chemokines to COAM versus GAGs were compared. COAM and heparan sulphate bound the mouse CXC chemokines KC/CXCL1, MIP-2/CXCL2, IP-10/CXCL10 and I-TAC/CXCL11 and the CC chemokine RANTES/CCL5 with affinities in the nanomolar range, whereas no binding interactions were observed for mouse MCP-1/CCL2, MIP-1α/CCL3 and MIP-1β/CCL4. The affinities of COAM-interacting chemokines were similar to or higher than those observed for heparan sulphate. Although COAM did not display chemotactic activity by itself, its co-administration with mouse GCP-2/CXCL6 and MIP-2/CXCL2 or its binding of endogenous chemokines resulted in fast and cooperative peritoneal neutrophil recruitment and in extravasation into the cremaster muscle in vivo. These local GAG mimetic features by COAM within tissues superseded systemic effects and were sufficient and applicable to reduce LPS-induced liver-specific neutrophil recruitment and activation. COAM mimics glycosaminoglycans and is a nontoxic probe for the study of leukocyte recruitment and inflammation in vivo.status: publishe

Interference with Glycosaminoglycan-Chemokine Interactions with a Probe to Alter Leukocyte Recruitment and Inflammation In Vivo

In vivo leukocyte recruitment is not fully understood and may result from interactions of chemokines with glycosaminoglycans/GAGs. We previously showed that chlorite-oxidized oxyamylose/COAM binds the neutrophil chemokine GCP-2/CXCL6. Here, mouse chemokine binding by COAM was studied systematically and binding affinities of chemokines to COAM versus GAGs were compared. COAM and heparan sulphate bound the mouse CXC chemokines KC/CXCL1, MIP-2/CXCL2, IP-10/CXCL10 and I-TAC/CXCL11 and the CC chemokine RANTES/CCL5 with affinities in the nanomolar range, whereas no binding interactions were observed for mouse MCP-1/CCL2, MIP-1 alpha/CCL3 and MIP-1 beta/CCL4. The affinities of COAM-interacting chemokines were similar to or higher than those observed for heparan sulphate. Although COAM did not display chemotactic activity by itself, its co-administration with mouse GCP-2/CXCL6 and MIP-2/CXCL2 or its binding of endogenous chemokines resulted in fast and cooperative peritoneal neutrophil recruitment and in extravasation into the cremaster muscle in vivo. These local GAG mimetic features by COAM within tissues superseded systemic effects and were sufficient and applicable to reduce LPS-induced liver-specific neutrophil recruitment and activation. COAM mimics glycosaminoglycans and is a nontoxic probe for the study of leukocyte recruitment and inflammation in vivo

Theoretical isoelectric points and carboxyterminal amino acid sequences of mouse chemokines.

<p>Basic amino acids (arginine, R; lysine, K) are underlined.</p

Effects of COAM co-treatment on LPS-induced systemic inflammation in the liver.

<p>(A) Co-application of COAM (2 mg/mouse) with intraperitoneally administrated LPS (1 mg/kg) decreases neutrophil infiltration to the liver at 4 h of inflammation; (B) representative images of neutrophils present in the liver sinusoids of LPS- and LPS plus COAM-treated mice (green cells – autofluorescent hepatocytes; 20x; scale bars represent 50 µm). Quantification of extracellular neutrophil elastase (C) and histone (D) within the livers of LPS and LPS+COAM-treated animals (mean area of staining per 20×FOV ± SD; scale bars represent 45 µm). Intravital visualization of NET deposition in the liver vasculature of LPS-treated and LPS plus COAM-treated mice (E). Staining for extracellular neutrophil elastase (NE) and histone illustrates clear deposition of these characteristic molecules of NETs in the liver after either treatment. In addition, overlay of histone and elastase staining is shown. Staining for extracellular DNA is presented with a higher magnification to clearly picture Sytox green deposition along the liver sinusoids; areas of the extDNA deposition are marked with red arrows. Neutrophil, elastase and histones were measured in five FOV/mouse, n = 5–7 animals per group; *<i>P</i><0.05.</p

Numbers of neutrophil-endothelial cell interactions observed 30 min following surgical preparation of the cremaster muscle after 3 h pretreatment with saline or COAM.

<p>*Numbers represent means ± SEM.</p