Sequential Sectioning of the Ulnar Collateral Ligament of the Elbow in Cadaveric Arms with Ulnohumeral Laxity Assessed by Dynamic Ultrasonography

Objectives: Injury of the ulnar collateral ligament (UCL), whether acute or chronic, is potentially career-threatening for elite overhead throwing athletes. Dynamic ultrasound (DUS) allows for rapid, cost-effective, non-invasive, and non-radiating evaluation of the UCL and elbow joint both at rest and with applied stress. The purpose of this study was to determine the amount of cadaveric elbow valgus laxity with sequential UCL sectioning using DUS. Our objective was to quantify which portions of the UCL must be injured to cause the varying levels of laxity seen clinically on DUS testing. No prior study has used DUS to quantify valgus joint laxity with sequential cadaveric UCL sectioning. It was hypothesized that the change in laxity due to release of the anterior band of the UCL would be greater than that seen when the posterior and transverse bands were cut. Methods: Twelve cadaveric elbows were dissected free of skin and subcutaneous tissue by an experienced orthopaedic surgeon. Baseline DUS at rest and with applied valgus stress was then performed by an experienced ultrasonographer. Sequential sectioning of the medial elbow soft-tissue stabilizing structures was then carried out with valgus stress applied to the joint at each sectioning interval utilizing a standardized device (Telos, Marburg, Germany). First the transverse band of the UCL was released, followed by the posterior band, then the anterior bundle of the anterior band, the remaining posterior bundle of the anterior band, and finally the complete flexor pronator mass. Results: Mean ulnohumeral laxity in millimeters with 95% CIs was calculated for each step of the sequence. The deltas between each step of the dissection were also calculated with means and 95% CIs. Mean baseline laxity of the unstressed ulnohumeral joint at rest was 3.2 mm (CI, 2.2-4.2); with the addition of valgus stress, mean laxity was 4.7 mm (CI, 3.5-6.0). When the transverse band was cut, ulnohumeral laxity increased to a mean of 5.5 mm (CI, 4.0-7.0). With release of the posterior band, mean laxity was 6.4 mm (CI, 4.3-8.5). When the anterior bundle of the anterior band of the UCL was cut, mean ulnohumeral laxity was 8.4 mm (CI, 5.7-11.0) and when the entire anterior band was released, mean laxity was 10.9 mm (CI, 7.8-14.0). Complete release of the flexor pronator muscle mass resulted in mean ulnohumeral laxity of 15.5 mm (CI, 12.9-18.1). The largest deltas were observed with release of the anterior bundle of the anterior band (2.0 mm; CI, 1.0-3.0), the entire anterior band (2.6 mm; CI, 1.3-3.8), and flexor pronator mass (4.6 mm; CI, 1.3-3.8). Release of the transverse and posterior bands of the UCL resulted in deltas of 0.74 mm (CI, 0.1-1.3) and 0.9 mm (CI, 0.3-1.5) respectively. Conclusion: DUS allows for rapid, cost-effective, non-invasive, non-radiating evaluation of the elbow joint and UCL both at rest and with applied valgus stress. Previous studies have indicated that DUS can identify abnormalities of the UCL associated with chronic degeneration and ligamentous injury including thickening of the anterior band of the UCL as well as hypoechoic foci/calcifications. The results of the current cadaveric study suggest that different changes in clinical laxity are seen on DUS with injury of particular bands of the UCL. Early identification and localization of injury to a particular band of the UCL may allow more appropriate selection of patients who will benefit from operative treatment. © The Author(s) 2013

Social perception drives eye-movement related brain activity: evidence from pro- and anti-saccades to faces

Social stimuli such as faces attract and retain attention to a greater extent than other objects. Using fMRI, we investigated how the activity of oculomotor and visual brain regions is modulated when participants look towards or away from visual stimuli belonging to different categories (faces and cars). We identified a region within the superior frontal sulcus showing greater difference between anti- and pro-saccades to faces than to cars, and thereby supporting inhibitory control in a social context. In contrast, ventral occipito-temporal regions and the amygdala, which are associated with face perception, showed higher activity for pro-saccades than anti-saccades for faces, but the reverse for cars, suggesting that contextual, top-down mechanisms modulate the functional specialisation of areas involved in perception. In addition, during saccades in the presence of faces, we found increased functional connectivity between the frontal eye-fields and other cortical and subcortical oculomotor structures, namely the inferior frontal eye field, the posterior parietal cortex and the basal ganglia, possibly reflecting the higher demand put on the oculomotor system to inhibit responses to socially salient stimuli. For the first time, these data highlight neural bases for the different orienting responses towards or away from faces as compared to other objects

Risk Factors for Nonplatelet Thromboxane Generation After Coronary Artery Bypass Graft Surgery

BACKGROUND: Persistent thromboxane (TX) generation while receiving aspirin therapy is associated with an increased risk of cardiovascular events. The Reduction in Graft Occlusion Rates (RIGOR) study found that aspirin-insensitive TXA2 generation, indicated by elevated urine 11-dehydro-TXB2 (UTXB2) 6 months after coronary artery bypass graft surgery, was a potent risk factor for vein graft thrombosis and originated predominantly from nonplatelet sources. Our goal was to identify risks factors for nonplatelet TXA2 generation. METHODS AND RESULTS: Multivariable modeling was performed by using clinical and laboratory variables obtained from 260 RIGOR subjects with verified aspirin-mediated inhibition of platelet TXA2 generation. The strongest variable associated with UTXB2 6 months after surgery, accounting for 47.2% of the modeled effect, was urine 8-iso-prostaglandin (PG)F2alpha, an arachidonic acid metabolite generated nonenzymatically by oxidative stress (standardized coefficient 0.442, P \u3c 0.001). Age, sex, race, lipid therapy, creatinine, left ventricular ejection fraction, and aspirin dose were also significantly associated with UTXB2 (P \u3c 0.03), although they accounted for only 4.8% to 10.2% of the modeled effect. Urine 8-iso-PGF2alpha correlated with risk of vein graft occlusion (odds ratio 1.67, P=0.001) but was not independent of UTXB2. In vitro studies revealed that endothelial cells generate TXA2 in response to oxidative stress and direct exposure to 8-iso-PGF2alpha. CONCLUSIONS: Oxidative stress-induced formation of 8-iso-PGF2alpha is strongly associated with nonplatelet thromboxane formation and early vein graft thrombosis after coronary artery bypass graft surgery. The endothelium is potentially an important source of oxidative stress-induced thromboxane generation. These findings suggest therapies that reduce oxidative stress could be useful in reducing cardiovascular risks associated with aspirin-insensitive thromboxane generation

The effects of grape seed extract on glycemic control, serum lipoproteins, inflammation, and body weight: A systematic review and meta-analysis of randomized controlled trials

The aim of this systematic review and meta-analysis was to analyze the effects of grape seed extract (GSE) on glycemic control and serum lipoproteins, inflammation and body weight. Two independent authors systematically searched online databases including EMBASE, Scopus, PubMed, Cochrane Library, and Web of Science from inception until May 30, 2019. Cochrane Collaboration risk of bias tool was applied to assess the methodological quality of included trials. The heterogeneity among the included studies was assessed using Cochrane's Q test and I-square (I2) statistic. Data were pooled using a random-effects model and weighted mean difference (WMD) was considered as the overall effect size. Fifty trials were included in this meta-analysis. Pooling effect sizes from studies demonstrated a significant decrease in fasting plasma glucose (FPG) (WMD): �2.01; 95 confidence interval (CI): �3.14, �0.86), total cholesterol (TC; WMD: �6.03; 95 CI: �9.71, �2.35), low-density lipoprotein (LDL) cholesterol (WMD: �4.97; 95 CI: �8.37, �1.57), triglycerides (WMD: �6.55; 95 CI: �9.28, �3.83), and C-reactive protein (CRP) concentrations (WMD: �0.81; 95 CI: �1.25, �0.38) following GSE therapy. Grape seed did not influence HbA1c, HDL cholesterol levels, and anthropometric measurements. This meta-analysis demonstrated that GSE intake significantly reduced FPG, TC, LDL cholesterol, triglycerides, and CRP levels. © 2019 John Wiley & Sons, Ltd

Project Coolbit: Can your watch predict heat stress and thermal comfort sensation?

10.1088/1748-9326/abd130ENVIRONMENTAL RESEARCH LETTERS16

Design and manufacture of a novel system to simulate the biomechanics of basic and pitching shoulder motion

Objectives: Cadaveric models of the shoulder evaluate discrete motion segments using the glenohumeral joint in isolation over a defined trajectory. The aim of this study was to design, manufacture and validate a robotic system to accurately create three-dimensional movement of the upper body and capture it using high-speed motion cameras. Methods: In particular, we intended to use the robotic system to simulate the normal throwing motion in an intact cadaver. The robotic system consists of a lower frame (to move the torso) and an upper frame (to move an arm) using seven actuators. The actuators accurately reproduced planned trajectories. The marker setup used for motion capture was able to determine the six degrees of freedom of all involved joints during the planned motion of the end effector. Results: The testing system demonstrated high precision and accuracy based on the expected versus observed displacements of individual axes. The maximum coefficient of variation for displacement of unloaded axes was less than 0.5% for all axes. The expected and observed actual displacements had a high level of correlation with coefficients of determination of 1.0 for all axes. Conclusions: Given that this system can accurately simulate and track simple and complex motion, there is a new opportunity to study kinematics of the shoulder under normal and pathological conditions in a cadaveric shoulder model

WRF-Comfort: simulating microscale variability in outdoor heat stress at the city scale with a mesoscale model

Urban overheating and its ongoing exacerbation due to global warming and urban development lead to increased exposure to urban heat and increased thermal discomfort and heat stress. To quantify thermal stress, specific indices have been proposed that depend on air temperature, mean radiant temperature (MRT), wind speed, and relative humidity. While temperature and humidity vary on scales of hundreds of meters, MRT and wind speed are strongly affected by individual buildings and trees and vary on the meter scale. Therefore, most numerical thermal comfort studies apply microscale models to limited spatial domains (commonly representing urban neighborhoods with building blocks) with resolutions on the order of 1 m and a few hours of simulation. This prevents the analysis of the impact of city-scale adaptation and/or mitigation strategies on thermal stress and comfort. To solve this problem, we develop a methodology to estimate thermal stress indicators and their subgrid variability in mesoscale models – here applied to the multilayer urban canopy parameterization BEP-BEM within the Weather Research and Forecasting (WRF) model. The new scheme (consisting of three main steps) can readily assess intra-neighborhood-scale heat stress distributions across whole cities and for timescales of minutes to years. The first key component of the approach is the estimation of MRT in several locations within streets for different street orientations. Second, mean wind speed and its subgrid variability are downscaled as a function of the local urban morphology based on relations derived from a set of microscale LES and RANS simulations across a wide range of realistic and idealized urban morphologies. Lastly, we compute the distributions of two thermal stress indices for each grid square, combining all the subgrid values of MRT, wind speed, air temperature, and absolute humidity. From these distributions, we quantify the high and low tails of the heat stress distribution in each grid square across the city, representing the thermal diversity experienced in street canyons. In this contribution, we present the core methodology as well as simulation results for Madrid (Spain), which illustrate strong differences between heat stress indices and common heat metrics like air or surface temperature both across the city and over the diurnal cycle.</p

Curved Beam Computed Tomography based Structural Rigidity Analysis of Bones with Simulated Lytic Defect: A Comparative Study with Finite Element Analysis

In this paper, a CT based structural rigidity analysis (CTRA) method that incorporates bone intrinsic local curvature is introduced to assess the compressive failure load of human femur with simulated lytic defects. The proposed CTRA is based on a three dimensional curved beam theory to obtain critical stresses within the human femur model. To test the proposed method, ten human cadaveric femurs with and without simulated defects were mechanically tested under axial compression to failure. Quantitative computed tomography images were acquired from the samples, and CTRA and finite element analysis were performed to obtain the failure load as well as rigidities in both straight and curved cross sections. Experimental results were compared to the results obtained from FEA and CTRA. The failure loads predicated by curved beam CTRA and FEA are in agreement with experimental results. The results also show that the proposed method is an efficient and reliable method to find both the location and magnitude of failure load. Moreover, the results show that the proposed curved CTRA outperforms the regular straight beam CTRA, which ignores the bone intrinsic curvature and can be used as a useful tool in clinical practices

Left Atrial Structure in Relationship to Age, Sex, Ethnicity, and Cardiovascular Risk Factors MESA (Multi-Ethnic Study of Atherosclerosis)

This research was supported by contracts N01-HC-95159, N01-HC-95160, N01-HC-95161, N01- HC-95162, N01-HC-95163, N01-HC-95164, N01-HC-95165, N01-HC-95166, N01-HC-95167, N01- HC-95168 and N01-HC-95169 from the National Heart, Lung, and Blood Institute and by grants UL1-TR-000040 and UL1-TR-001079 from the National Center for Research Resources. Prof. Petersen and Drs. Zemrak and Mohiddin gratefully acknowledge funding from the National Institute for Health Research Cardiovascular Biomedical Research Unit at Barts. Prof. Petersen’s work is supported by awards establishing the Farr Institute of Health Informatics Research at University College London Partners from the Medical Research Council, in partnership with Arthritis Research United Kingdom, the British Heart Foundation, Cancer Research United Kingdom, the Economic and Social Research Council, the Engineering and Physical Sciences Research Council, the National Institute of Health Research, the National Institute for Social Care and Health Research (Welsh Assembly Government), the Chief Scientist Office (Scottish Government Health Directorates), and the Wellcome Trust (MR/K006584/1)