Impact of Center Experience on Patient Radiation Exposure During Transradial Coronary Angiography and Percutaneous Intervention: A Patient-Level, International, Collaborative, Multi-Center Analysis.

BACKGROUND: The adoption of the transradial (TR) approach over the traditional transfemoral (TF) approach has been hampered by concerns of increased radiation exposure-a subject of considerable debate within the field. We performed a patient-level, multi-center analysis to definitively address the impact of TR access on radiation exposure. METHODS AND RESULTS: Overall, 10 centers were included from 6 countries-Canada (2 centers), United Kingdom (2), Germany (2), Sweden (2), Hungary (1), and The Netherlands (1). We compared the radiation exposure of TR versus TF access using measured dose-area product (DAP). To account for local variations in equipment and exposure, standardized TR:TF DAP ratios were constructed per center with procedures separated by coronary angiography (CA) and percutaneous coronary intervention (PCI). Among 57 326 procedures, we demonstrated increased radiation exposure with the TR versus TF approach, particularly in the CA cohort across all centers (weighted-average ratios: CA, 1.15; PCI, 1.05). However, this was mitigated by increasing TR experience in the PCI cohort across all centers (r=-0.8; P=0.005). Over time, as a center transitioned to increasing TR experience (r=0.9; P=0.001), a concomitant decrease in radiation exposure occurred (r=-0.8; P=0.006). Ultimately, when a center's balance of TR to TF procedures approaches 50%, the resultant radiation exposure was equivalent. CONCLUSIONS: The TR approach is associated with a modest increase in patient radiation exposure. However, this increase is eliminated when the TR and TF approaches are used with equal frequency-a guiding principle for centers adopting the TR approach

Downregulation of the Hsp90 System Causes Defects in Muscle Cells of Caenorhabditis Elegans

The ATP-dependent molecular chaperone Hsp90 is required for the activation of a variety of client proteins involved in various cellular processes. Despite the abundance of known client proteins, functions of Hsp90 in the organismal context are not fully explored. In Caenorhabditis elegans, Hsp90 (DAF-21) has been implicated in the regulation of the stress-resistant dauer state, in chemosensing and in gonad formation. In a C. elegans strain carrying a DAF-21 mutation with a lower ATP turnover, we observed motility defects. Similarly, a reduction of DAF-21 levels in wild type nematodes leads to reduced motility and induction of the muscular stress response. Furthermore, aggregates of the myosin MYO-3 are visible in muscle cells, if DAF-21 is depleted, implying a role of Hsp90 in the maintenance of muscle cell functionality. Similar defects can also be observed upon knockdown of the Hsp90-cochaperone UNC-45. In life nematodes YFP-DAF-21 localizes to the I-band and the M-line of the muscular ultrastructure, but the protein is not stably attached there. The Hsp90-cofactor UNC-45-CFP contrarily can be found in all bands of the nematode muscle ultrastructure and stably associates with the UNC-54 containing A-band. Thus, despite the physical interaction between DAF-21 and UNC-45, apparently the two proteins are not always localized to the same muscular structures. While UNC-45 can stably bind to myofilaments in the muscular ultrastructure, Hsp90 (DAF-21) appears to participate in the maintenance of muscle structures as a transiently associated diffusible factor

The structural basis of interlamellar cohesion in the intervertebral disc wall

The purpose of this study was to investigate the structural mechanisms that create cohesion between the concentric lamellae comprising the disc annulus. Sections, 50–60 µm thick, were obtained using a carefully chosen cutting plane that incorporated the fibrous component in alternating lamellae as in-plane and cross-sectioned arrays. These sections were then subjected to microtensile stretching both across (radial) and along (tangential) the in-plane fibre direction, in their fully hydrated state. Structural responses were studied by simultaneously viewing the sections using high-resolution Nomarski interference contrast light microscopy. Additional bulk samples of annulus were fixed while held in a constant, radially stretched state in order to investigate the potential for interlamellar separation to occur in a state more representative of the intact disc wall. The study has provided a detailed picture of the structural architecture creating disc wall cohesion, revealing a complex hierarchy of interconnecting relationships within the disc wall, not previously described. Importantly, because our experimental approach offers a high-resolution view of the response of the interlamellar junction to deformation in its fully hydrated condition, it is a potentially useful method for investigating subtle changes in junction cohesion resulting from both early degeneration and whole-disc trauma

Safety in Mixed Martial Arts: a 7-Year Review of Cancelled MMA Bouts in Calgary, Alberta, During the Pre-bout Medical Examination Period

Abstract Background Presently, there is no literature that examines the reasons for the cancellation of amateur or professional mixed martial arts (MMA) bouts. The purpose of this study was to review the circumstances that lead to the cancellation of MMA bouts by Calgary ringside physicians during the pre-bout examination period and to identify any emerging patterns that may guide the regulatoin of this sport. Methods The case-series  was constructed from the Calgary Combative Sports Commission pre-bout examination records and the medical records submitted by each athlete from January 2010 to December 2016. Results Cancelled bouts in the pre-bout examination periods represented 5.4% of all MMA bouts in Calgary. A total of 25 reasons lead to bout cancellation and included the following: failure to obtain required neuroimaging (28.0%), neuroimaging abnormalities (24.0%), incomplete routine screening investigations (16.0%), exceeding maximum weight differential between the two athletes (16.0%), injury in the pre-competition period (8.0%), dehydration (4.0%), and ECG abnormalities (4.0%). The abnormalities on neuroimaging (n of 6) included the following: post traumatic gliosis on MRI (n = 1, 16.7%), flares diffusely and findings consistent with microhemorrhage on MRI (n = 1, 16.7%), chronic orbital fracture with fat pad extrusion on CT (n = 2, 33.3%), lacunar infarct on MRI (1), and unspecified MRI abnormality (n = 1, 16.7%). Twenty-two athletes had bouts cancelled and of these three athletes had their bouts stopped for two reasons. Conclusions The following recommendations are presented and include: the creation of guidelines regarding pre- and post-bout neuroimaging, the implementation of industry-wide minimum medical screening standards, the adoption of a longitudinal approach to weight monitoring, the development of competent ringside physician groups, and active oversight by the Combative Sports Commission during the matchmaking process