Towards a more refined insight in the critical motivating features of choice : an experimental study among recreational rope skippers

Objective: The question whether choice is a motivation and engagement-enhancing practice is a much debated subject, both theoretically as well as in practice. Therefore, the present study examined the impact of different types of choice on engagement and intended perseverance. Design: and method: In a sample of Belgian rope skippers (n = 159; M-age = 17.17; SDage = 8.43) an experimental field design was implemented, in which three different choice conditions were compared to a no-choice comparison group. Results: Results indicated that being offered choice with regard the type of exercises (i.e. option choice) were mixed, with choice yielding a clear engagement and perseverance-enhancing effect compared to a no choice control group in cases the offered options differed clearly from one another (i.e., high contrast option choice), while no benefits were observed in case choice options leaned closely to one another (i.e. low contrast option choice). Athletes' involvement in the order of exercises during a training session (i.e. action choice) tended to enhance athletes' engagement, but not their intentional perseverance, compared to a no choice control group. Finally, all experimentally offered choices yielded a positive effect on two aspects of autonomy need satisfaction, that is, perceived choice and felt volition. These two variables functioned as a chain of mechanisms through which different types of choice related to athlete engagement and intended perseverance. These effects emerged irrespective of rope-skippers' dispositional indecisiveness. Conclusion: The discussion highlights the importance of a nuanced discussion regarding the topic of choice, thereby contrasting the different pros and cons associated with each type of choice

MECHANICAL MUSCLE PROPERTIES AFTER TWO TYPES OF PLYOMETRIC TRAINING

Strength training effects may be highly specific. This suggestion is not always supported by previous research. Most training studies use strength measures to evaluate the effect of the program. It seems reasonable that a measure of strength does not fully describe the training adaptation. Therefore the design of this experiment is different. All subjects performed a set of 18 maximal contractions (isometric, isokinetic and plyometric) before and after training. Based on this set of measurements a mechanical muscle model was quantified. The coefficients of the model represent muscle properties which underlie force development (force-length, force-velocity relationship and contraction history). By studying the changes of the coefficients an attempt is made to speculate further on the underlying mechanisms which. may be responsible for the strength increase. The proposed study is designed to evaluate the use of a muscle model in investigating training programs. The subjects were divided in 3 groups: one control group (N=10) and two training groups (N=2*10). The training program involved plyometric contractions for the elbowflexors 3 dayslweek for a period of 6 weeks. These plyometric movements consisted of two successive contractions (concentric + kccentric) over an amplitude of 120" at 60"ls. The only difference between both training programs was the fact that sequence of those contractions was reversed namely concentric-eccentric for the CE-group and eccentricconcentric for the EC-group. The three groups (CE, EC. Control) showed no difference in isometric strength pre and post training. For the dynamic strength a significant improvement (P < 0.05) was observed only for both training groups. CE-training resulted in a significant change of the coefficients representing the force-velocity relationship (P < 0.05 for the ecc. part and P < 0.01 for the conc. part). The negative effect of a concentric contraction history was significantly reduced after the EC-training (P < 0.05). It can be concluded that both training groups made similar gains in dynamic force. However, analysis using the model showed that the cause of these force gains was different. For the CE-group the improvement in dynamic force can be attributed to an ameliorated force-velocity relationship whereas for the ECgroup this was due to a reduced influence of the concentric contraction historv. Specific changes in force development after training can be studied using a muscle model. These findings are a useful contribution in determining specific effects of training

Development and validation of the characteristics of resilience in sports teams inventory

This multi-study paper reports the development and initial validation of an inventory for the Characteristics of Resilience in Sports Teams (CREST). In four related studies, 1225 athletes from Belgium and the United Kingdom were sampled. The first study provided content validity for an initial item set. The second study explored the factor structure of the CREST, yielding initial evidence but no conclusive results. In contrast, the third and fourth study provided evidence for a two-factor measure, reflecting (a) the team’s ability to display resilient characteristics and (b) the vulnerabilities being displayed under pressure. Overall, the CREST was shown to be reliable at the between-players and the between-teams level, as well as over time. Moreover, its concurrent validity was verified by linking the characteristics of team resilience with various relevant team processes. Its discriminant validity was established by comparing the CREST measures with individual athletes’ resilient traits. In conclusion, the CREST was argued to be a usable state-like measure of team-level resilient characteristics and vulnerabilities. To gain further understanding of team resilience as a process, this measurement could be used in future process-oriented research examining adverse events and sports team’s pre- and post-adversity functioning

Histone deacetylase inhibitors in multiple myeloma

Novel drugs such as bortezomib and high-dose chemotherapy combined with stem cell transplantation improved the outcome of multiple myeloma patients in the past decade. However, multiple myeloma often remains incurable due to the development of drug resistance governed by the bone marrow microenvironment. Therefore targeting new pathways to overcome this resistance is needed. Histone deacetylase (HDAC) inhibitors represent a new class of anti-myeloma agents. Inhibiting HDACs results in histone hyperacetylation and alterations in chromatine structure, which, in turn, cause growth arrest differentiation and/or apoptosis in several tumor cells. Here we summarize the molecular actions of HDACi as a single agent or in combination with other drugs in different in vitro and in vivo myeloma models and in (pre-)clinical trials

Coaching the coach : intervention effects on need-supportive coaching behavior and athlete motivation and engagement

The present intervention study examined whether youth sport coaches can be trained in adopting a need-supportive (i.e., autonomy support and structure) coaching style to the benefit of youth athletes' autonomous motivation and engagement. Participants were 43 coaches (33 men, 10 women) and 326 youth athletes (221 boys, 105 girls), active in 12 team or individual sports. Sport coaches were randomly assigned to either a control or intervention condition. The training involved a workshop trajectory spanning four sessions on how to incorporate a (more) need-supportive coaching style. As for coaches' self-reported coaching style, results of multilevel modelling revealed positive effects on autonomy support and control at posttest, and additional effect on structure and control from pre-test to follow-up (i.e., 4 months later) compared to coaches in the control condition. As for athletes' reports, multilevel modelling showed that athletes of coaches in the intervention, relative to those involved in the control group, perceived their coach to be more autonomy-supportive, more structuring, and less chaotic from pre-to posttest, with these effects being more pronounced for athletes of team sports. Further, athletes of coaches in the intervention group reported being more autonomously motivated and more engaged compared to those of coaches in the control group. Overall, the present findings indicate that sport coaches can become more skilled in adopting a need-supportive coaching style, to the benefit of athletes' autonomous motivation and engagement

Systemic levels of interleukin-6 and matrix metalloproteinase-9 in patients with multiple myeloma may be useful as prognostic indexes of bone disease

Multiple myeloma is characterized by accelerated production of the proteolytic enzyme matrix metalloproteinase (MMP)-9. We hypothesized that myeloma- produced MMP-9 may influence the rate of bone turnover in a paracrine manner. Thus, we examined the correlations of MMP-9 levels, disease severity, and bone turnover rate as evaluated by markers of bone formation and resorption. Thirty-seven newly diagnosed multiple myeloma patients (nine of Durie-Salmon stage I, 12 of stage II and 16 of stage III) and 12 age-matched controls were studied. Serum MMP-9 levels were significantly higher at stage II compared to stage I (188.78 91.27 vs. 59.25 33.09 ng/mL, p-0.004). Additionally, free urine pyridinolines (F-Pyd), free urine deoxy-pyridinolines (F-Dpd) and urine N-telopeptide fragment (NTx) were elevated, their level correlating with disease stage (p-0.001, p-0.03, p-0.001, respectively), as were bone marrow infiltration and serum interleukin- 6 (IL-6) levels (p-0.0001, p-0.01, respectively). MMP-9 levels were lower in patients compared with controls (p-0.001), whereas IL-6 and bone resorption marker levels were higher in patients than in controls (p-0.001 in all cases). Significant correlation was found between infiltration, MMP-9, free urine pyd, free urine dpd and NTx for each stage of the disease (p-0.03, p-0.003, p-0.002, p-0.003 and p-0.001, respectively). Levels of MMP-9 and of IL-6 in multiple myeloma correlate well with bone turnover rate and may be useful in disease evaluation

PTHrP-induced MCP-1 production by human bone marrow endothelial cells and osteoblasts promotes osteoclast differentiation and prostate cancer cell proliferation and invasion in vitro

Prostate cancer (PCa) preferentially metastasizes to bone resulting in osteoblastic lesions with underlying osteolytic activities. The mechanisms through which PCa cells promote osteolytic activities and subsequent osteoblastic bone formation remain poorly understood. Parathyroid hormone-related protein (PTHrP), produced by bone cells and PCa, binds to receptors on osteoblasts and stimulates bone formation and resorption. We have previously reported that MCP-1 acts as a paracrine and autocrine factor for PCa progression. However, the role of PTHrP in regulating MCP-1 expression in bone microenvironment, specifically by human bone marrow endothelial cells (HBME) and osteoblasts (hFOB), as well as by PCa cells, has not been studied. Accordingly, we first determined the effect of PTHrP on MCP-1 expression by bone cells and PCa cells. PTHrP induced both MCP-1 protein and mRNA expression by HBME and hFOB cells, but not by PCa LNCaP and PC3 cells. To further determine the mechanisms of PTHrP-induced MCP-1 transcription, analysis of the MCP-1 promoter was performed. MCP-1 promoter activity was induced by PTHrP. Both C/EBPΒ and NF-ΚB binding elements are required for PTHrP-induced MCP-1 transcription. Finally, when a constitutively-active PTH receptor construct was transfected into HBME and hFOB cells, MCP-1 production was increased. The conditioned media collected from these cells induced osteoclast differentiation and PC3 proliferation and invasion in vitro . These inductions were partially inhibited by MCP-1 neutralizing antibody. We conclude that PTHrP-induced MCP-1 production by HBME and hFOB cells promotes osteoclast differentiation in vitro and such induction may play a critical role in PCa development in the bone microenvironment. © 2007 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56050/1/22704_ftp.pd

Vascular Stem/Progenitor Cell Migration Induced by Smooth Muscle Cell-Derived Chemokine (C-C Motif) Ligand 2 and Chemokine (C-X-C motif) Ligand 1 Contributes to Neointima Formation

Recent studies have shown that Sca-1+ (stem cell antigen-1) stem/progenitor cells within blood vessel walls may contribute to neointima formation, but the mechanism behind their recruitment has not been explored. In this work Sca-1+ progenitor cells were cultivated from mouse vein graft tissue and found to exhibit increased migration when cocultured with smooth muscle cells (SMCs) or when treated with SMC-derived conditioned medium. This migration was associated with elevated levels of chemokines, CCL2 (chemokine (C-C motif) ligand 2) and CXCL1 (chemokine (C-X-C motif) ligand 1), and their corresponding receptors on Sca-1+ progenitors, CCR2 (chemokine (C-C motif) receptor 2) and CXCR2 (chemokine (C-X-C motif) receptor 2), which were also upregulated following SMC conditioned medium treatment. Knockdown of either receptor in Sca-1+ progenitors significantly inhibited cell migration. The GTPases Cdc42 and Rac1 were activated by both CCL2 and CXCL1 stimulation and p38 phosphorylation was increased. However, only Rac1 inhibition significantly reduced migration and p38 phosphorylation. After Sca-1+ progenitors labeled with green fluorescent protein (GFP) were applied to the adventitial side of wire-injured mouse femoral arteries, a large proportion of GFP-Sca-1+-cells were observed in neointimal lesions, and a marked increase in neointimal lesion formation was seen 1 week post-operation. Interestingly, Sca-1+ progenitor migration from the adventitia to the neointima was abrogated and neointima formation diminished in a wire injury model using CCL2−/− mice. These findings suggest vascular stem/progenitor cell migration from the adventitia to the neointima can be induced by SMC release of chemokines which act via CCR2/Rac1/p38 and CXCR2/Rac1/p38 signaling pathways. Stem Cells 2016;34:2368–2380

Tracking human multiple myeloma xenografts in NOD-Rag-1/IL-2 receptor gamma chain-null mice with the novel biomarker AKAP-4

<p>Abstract</p> <p>Background</p> <p>Multiple myeloma (MM) is a fatal malignancy ranking second in prevalence among hematological tumors. Continuous efforts are being made to develop innovative and more effective treatments. The preclinical evaluation of new therapies relies on the use of murine models of the disease.</p> <p>Methods</p> <p>Here we describe a new MM animal model in NOD-Rag1null IL2rgnull (NRG) mice that supports the engraftment of cell lines and primary MM cells that can be tracked with the tumor antigen, AKAP-4.</p> <p>Results</p> <p>Human MM cell lines, U266 and H929, and primary MM cells were successfully engrafted in NRG mice after intravenous administration, and were found in the bone marrow, blood and spleen of tumor-challenged animals. The AKAP-4 expression pattern was similar to that of known MM markers, such as paraproteins, CD38 and CD45.</p> <p>Conclusions</p> <p>We developed for the first time a murine model allowing for the growth of both MM cell lines and primary cells in multifocal sites, thus mimicking the disease seen in patients. Additionally, we validated the use of AKAP-4 antigen to track tumor growth <it>in vivo </it>and to specifically identify MM cells in mouse tissues. We expect that our model will significantly improve the pre-clinical evaluation of new anti-myeloma therapies.</p