405 research outputs found

    Sync or separate? No compelling evidence for unintentional interpersonal coordination between Usain Bolt and Tyson Gay on the 100-meter world record race

    Get PDF
    In a recent observation article in Journal of Experimental Psychology: Human Perception and Performance (JEP:HPP; Varlet & Richardson, 2015) the 100-m sprint final of the World Championship in Athletics in Berlin of 2009 (i.e., the current world record race) was analyzed. That study reported occurrence of spontaneous, unintentional interpersonal synchronization between Usain Bolt and Tyson Gay, the respective winner and runner-up of that race. In the present commentary article, however, we argue that the results and conclusion of that study cannot be warranted because of methodological shortcomings. We addressed the same research question and reassessed the same race using an alternative data analysis method. These results revealed that as yet there is no sufficient ground to conclude that in the 100-m world record race synchronization occurred between Bolt and Gay. Yet, our reanalysis suggested that even at this very elite level the individual movement frequencies did seem to vary to such an extent that synchronization would theoretically still be possible, thereby providing incentives for further examination of potential unintentional synchronization in coactive sports

    PG-mediated closure of paracellular pathway and not restitution is the primary determinant of barrier recovery in acutely injured porcine ileum

    Get PDF
    Small bowel epithelium is at the frontline of intestinal barrier function. Restitution is considered to be the major determinant of epithelial repair as function recovers in parallel with restitution after acute injury. As such, studies of intact mucosa have largely been replaced by migration assays of cultured epithelia. These latter studies fail to account for the simultaneous roles played by villous contraction and paracellular permeability in recovery of barrier function. Non-steroidal anti-inflammatory drugs (NSAID) result in increased intestinal permeability and disease exacerbation in patients with IBD. Thus, we examined the reparative attributes of endogenous prostaglandins (PG) after injury of ileal mucosa by deoxycholate (6 mM) in Ussing chambers. Recovery of transepithelial resistance (TER) from 20–40 Ω.cm2 was abolished by indomethacin (INDO), whereas restitution of 40–100% of the villous surface was unaffected despite concurrent arrest of villous contraction. In the presence of PG, resident crypt and migrating epithelial cells were tightly apposed. In tissues treated with INDO, crypt epithelial cells had dilated intercellular spaces that were accentuated in the migrating epithelium. TER was fully rescued from the effects of INDO by osmotic-driven collapse of the paracellular space and PG-mediated recovery was significantly impaired by blockade of Cl− secretion. These studies are the first to clearly distinguish the relative contribution of paracellular resistance versus restitution to acute recovery of epithelial barrier function. Restitution was ineffective in the absence of PG-mediated paracellular space closure. Failure of PG-mediated repair mechanisms may underlie barrier failure resulting from NSAID use in patients with underlying enteropathy

    Prostaglandins I2 and E2 have a synergistic role in rescuing epithelial barrier function in porcine ileum.

    Get PDF
    Prostaglandins (PG) are cytoprotective for gastrointestinal epithelium, possibly because they enhance mucosal repair. The objective of the present studies was to assess the role of prostaglandins in intestinal repair. Intestinal mucosa from porcine ileum subjected to 1 h of ischemia was mounted in Ussing chambers. Recovery of normal transepithelial electrical resistance occurred within 2 h, and continued to increase for a further 2 h to a value twice that of control. The latter response was blocked by inhibition of prostaglandin synthesis, and restored by addition of both carbacyclin (an analog of PGI2) and PGE2, whereas the addition of each alone had little effect. Histologically, prostaglandins had no effect on epithelial restitution or villous contraction, indicating that elevations in transepithelial resistance were associated with increases in paracellular resistance. Furthermore, prostaglandin-stimulated elevations in resistance were inhibited with cytochalasin D, an agent known to stimulate cytoskeletal contraction. Synergistic elevations in transepithelial resistance, similar to those of carbacyclin and PGE2, were also noted after treatment with cAMP and {"type":"entrez-nucleotide","attrs":{"text":"A23187","term_id":"833253","term_text":"A23187"}}A23187 (a calcium ionophore). We conclude that PGE2 and PGI2 have a synergistic role in restoration of intestinal barrier function by increasing intracellular cAMP and Ca2+, respectively, which in turn signal cytoskeletal-mediated tight junction closure

    Ex vivo effect of gold nanoparticles on porcine synovial membrane

    Get PDF
    Gold nanoparticles (AuNPs) have great potential as carriers for local drug delivery and as a primary therapeutic for treatment of inflammation. Here we report on the AuNP-synovium interaction in an ex vivo model of intra-articular application for treatment of joint inflammation. Sheets of porcine femoropatellar synovium were obtained post mortem and each side of the tissue samples was maintained in a separate fluid environment. Permeability to AuNPs of different sizes (5−52 nm) and biomarker levels of inflammation were determined to characterize the ex vivo particle interaction with the synovium. Lipopolysaccharide or recombinant human interleukin-1β were added to fluid environments to assess the ex vivo effect of pro-inflammatory factors on permeability and biomarker levels. The synovium showed size selective permeability with only 5 nm AuNPs effectively permeating the entire tissues’ width. This process was further governed by particle stability in the fluid environment. AuNPs reduced matrix metalloproteinase and lactate dehydrogenase activity and hyaluronic acid concentrations but had no effect on prostaglandin E(2) levels. Exposure to pro-inflammatory factors did not significantly affect AuNP permeation or biomarker levels in this model. Results with ex vivo tissue modeling of porcine synovium support an anti-inflammatory effect of AuNPs warranting further investigation
    • …
    corecore