Applying metabolomics to cardiometabolic intervention studies and trials: past experiences and a roadmap for the future

Metabolomics and lipidomics are emerging methods for detailed phenotyping of small molecules in samples. It is hoped that such data will: (i) enhance baseline prediction of patient response to pharmacotherapies (beneficial or adverse); (ii) reveal changes in metabolites shortly after initiation of therapy that may predict patient response, including adverse effects, before routine biomarkers are altered; and( iii) give new insights into mechanisms of drug action, particularly where the results of a trial of a new agent were unexpected, and thus help future drug development. In these ways, metabolomics could enhance research findings from intervention studies. This narrative review provides an overview of metabolomics and lipidomics in early clinical intervention studies for investigation of mechanisms of drug action and prediction of drug response (both desired and undesired). We highlight early examples from drug intervention studies associated with cardiometabolic disease. Despite the strengths of such studies, particularly the use of state-of-the-art technologies and advanced statistical methods, currently published studies in the metabolomics arena are largely underpowered and should be considered as hypothesis-generating. In order for metabolomics to meaningfully improve stratified medicine approaches to patient treatment, there is a need for higher quality studies, with better exploitation of biobanks from randomized clinical trials i.e. with large sample size, adjudicated outcomes, standardized procedures, validation cohorts, comparison witth routine biochemistry and both active and control/placebo arms. On the basis of this review, and based on our research experience using clinically established biomarkers, we propose steps to more speedily advance this area of research towards potential clinical impact

Does the Use of Computer-Generated Slide Presentations in the Classroom Affect Student Performance and Interest?

This paper examines how computer-assisted instruction affects students. The use of computer-generated slide presentations in an introductory economics course is examined for potential effects on student performance, student attitudes, and the evaluations of the instructor. Multiple sections of Introductory Economics are used to determine if the use of computer-generated slide presentations has any effect on students in the areas listed above. Control variables used are student ability, gender, classification, and prior exposure to economics. The results indicate that the use of computer-generated slide presentations has no effect on student performance, attitudes, or evaluation of the instructor.Economics; Introductory Economics

The impact of item-writing flaws and item complexity on examination item difficulty and discrimination value

Citation: Rush, B. R., Rankin, D. C., & White, B. J. (2016). The impact of item-writing flaws and item complexity on examination item difficulty and discrimination value. BMC Medical Education, 16(1). doi:10.1186/s12909-016-0773-3Background: Failure to adhere to standard item-writing guidelines may render examination questions easier or more difficult than intended. Item complexity describes the cognitive skill level required to obtain a correct answer. Higher cognitive examination items promote critical thinking and are recommended to prepare students for clinical training. This study evaluated faculty-authored examinations to determine the impact of item-writing flaws and item complexity on the difficulty and discrimination value of examination items used to assess third year veterinary students. Methods: The impact of item-writing flaws and item complexity (cognitive level I-V) on examination item difficulty and discrimination value was evaluated on 1925 examination items prepared by clinical faculty for third year veterinary students. Results: The mean (± SE) percent correct (83.3 % ± 17.5) was consistent with target values in professional education, and the mean discrimination index (0.18 ± 0.17) was slightly lower than recommended (0.20). More than one item-writing flaw was identified in 37.3 % of questions. The most common item-writing flaws were awkward stem structure, implausible distractors, longest response is correct, and responses are series of true-false statements. Higher cognitive skills (complexity level III-IV) were required to correctly answer 38.4 % of examination items. As item complexity increased, item difficulty and discrimination values increased. The probability of writing discriminating, difficult examination items decreased when implausible distractors and all of the above were used, and increased if the distractors were comprised of a series of true/false statements. Items with four distractors were not more difficult or discriminating than items with three distractors. Conclusion: Preparation of examination questions targeting higher cognitive levels will increase the likelihood of constructing discriminating items. Use of implausible distractors to complete a five-option multiple choice question does not strengthen the discrimination value. © 2016 The Author(s)

Post-operative atrial fibrillation is influenced by beta-blocker therapy but not by pre-operative atrial cellular electrophysiology

We investigated whether post-cardiac surgery (CS) new-onset atrial fibrillation (AF) is predicted by pre-CS atrial cellular electrophysiology, and whether the antiarrhythmic effect of beta-blocker therapy may involve pre-CS pharmacological remodeling. Atrial myocytes were obtained from consenting patients in sinus rhythm, just prior to CS. Action potentials and ion currents were recorded using whole-cell patch-clamp technique. Post-CS AF occurred in 53 of 212 patients (25%). Those with post-CS AF were older than those without (67 ± 2 vs 62 ± 1 years, P = 0.005). In cells from patients with post-CS AF, the action potential duration at 50% and 90% repolarization, maximum upstroke velocity, and effective refractory period (ERP) were 13 ± 4 ms, 217 ± 16 ms, 185 ± 10 V/s, and 216 ± 14 ms, respectively (n = 30 cells, 11 patients). Peak L-type Ca2+ current, transient outward and inward rectifier K+ currents, and the sustained outward current were −5.0 ± 0.5, 12.9 ± 2.4, −4.1 ± 0.4, and 9.7 ± 1.0 pA/pF, respectively (13-62 cells, 7-19 patients). None of these values were significantly different in cells from patients without post-CS AF (P > 0.05 for each, 60-279 cells, 29-86 patients), confirmed by multiple and logistic regression. In patients treated >7 days with a beta-blocker pre-CS, the incidence of post-CS AF was lower than in non-beta-blocked patients (13% vs 27%, P = 0.038). Pre-CS beta-blockade was associated with a prolonged pre-CS atrial cellular ERP (P = 0.001), by a similar degree (∼20%) in those with and without post-CS AF. Conclusion: Pre-CS human atrial cellular electrophysiology does not predict post-CS AF. Chronic beta-blocker therapy is associated with a reduced incidence of post-CS AF, unrelated to a pre-CS ERP-prolonging effect of this treatment

Improved Path Planning Onboard the Mars Exploration Rovers

A revised version of the AutoNav (autonomous navigation with hazard avoidance) software running onboard each Mars Exploration Rover (MER) affords better obstacle avoidance than does the previous version. Both versions include GESTALT (Grid-based Estimation of Surface Traversability Applied to Local Terrain), a navigation program that generates local-terrain models from stereoscopic image pairs captured by onboard rover cameras; uses this information to evaluate candidate arcs that extend across the terrain from the current rover location; ranks the arcs with respect to hazard avoidance, minimization of steering time, and the direction towards the goal; and combines the rankings in a weighted vote to select an arc, along which the rover is then driven. GESTALT works well in navigating around small isolated obstacles, but tends to fail when the goal is on the other side of a large obstacle or multiple closely spaced small obstacles. When that occurs, the goal seeking votes and hazard avoidance votes conflict severely. The hazard avoidance votes will not allow the rover to drive through the unsafe area, and the waypoint votes will not allow enough deviation from the straight-line path for the rover to get around the hazard. The rover becomes stuck and is unable to reach the goal. The revised version of AutoNav utilizes a global path-planning program, Field D*, to evaluate the cost of traveling from the end of each GESTALT arc to the goal. In the voting process, Field D* arc votes supplant GESTALT goal-seeking arc votes. Hazard avoidance, steering bias, and Field D* votes are merged and the rover is driven a preset distance along the arc with the highest vote. Then new images are acquired and the process as described is repeated until the goal is reached. This new technology allows the rovers to autonomously navigate around much more complex obstacle arrangements than was previously possible. In addition, this improved autonomy enables longer traverses per Sol (a day on Mars), and can make planning drives easier for operators on Earth

Temporary Single-Cell Coating for Bioprocessing with a Cationic Polymer

Temporary single-cell coating is a useful tool for cell processing, allowing manipulation of cells to prevent cell attachment and agglomeration, before re-establishing normal cell function. In this work, a speckled coating method using a known polycation [poly(l-lysine), PLL] is described to induce cell surface electrostatic charges on three different cell types, namely, two bone cancer cell lines and fibroblasts. The morphology of the PLL speckled coating on the cell surface, internalization and metabolization of the polymer, and prevention of cellular aggregations are reported. Polymer concentration was found to be the key parameter controlling both capsule morphology and cell health. This approach allows a temporary cell coating over the course of 1–2 h, with cells exhibiting phenotypically normal behavior after ingesting and metabolizing the polymer. The process offers a fast and efficient alternative to aid single-cell manipulation for bioprocessing applications. Preliminary work on the application of PLL speckled cell coating in enabling reliable bioprinting is also presented

AXL modulates extracellular matrix protein expression and is essential for invasion and metastasis in endometrial cancer

The receptor tyrosine kinase AXL promotes migration, invasion, and metastasis. Here, we evaluated the role of AXL in endometrial cancer. High immunohistochemical expression of AXL was found in 76% (63/83) of advanced-stage, and 77% (82/107) of high-grade specimens and correlated with worse survival in uterine serous cancer patients. In vitro, genetic silencing of AXL inhibited migration and invasion but had no effect on proliferation of ARK1 endometrial cancer cells. AXL-deficient cells showed significantly decreased expression of phospho-AKT as well as uPA, MMP-1, MMP-2, MMP-3, and MMP-9. In a xenograft model of human uterine serous carcinoma with AXL-deficient ARK1 cells, there was significantly less tumor burden than xenografts with control ARK1 cells. Together, these findings underscore the therapeutic potentials of AXL as a candidate target for treatment of metastatic endometrial cancer

The experimental gas-phase structures of 1,3,5-trisilylbenzene and hexasilylbenzene and the theoretical structures of all benzenes with three or more silyl substituents

The structures of 1,3,5-trisilylbenzene and hexasilylbenzene in the gas phase have been determined by electron diffraction, and that of 1,3,5-trisilylbenzene by X-ray crystallography. The structures of three trisilylbenzene isomers, three tetrasilylbenzenes, pentasilylbenzene and hexasilylbenzene have been computed, ab initio and using Density Functional Theory, at levels up to MP2/6-31G*. The primary effect of silyl substituents is to narrow the ring angle at the substituted carbon atoms. Steric interactions between silyl groups on neighbouring carbon atoms lead first to displacement of these groups away from one another, and then to displacement out of the ring plane, with alternate groups moving to opposite sides of the ring. In the extreme example, hexasilylbenzene, the SiCCSi dihedral angle is 17.8(8)°

Targeting lentiviral vectors to antigen-specific immunoglobulins

Gene transfer into B cells by lentivectors can provide an alternative approach to managing B lymphocyte malignancies and autoreactive B cell-mediated autoimmune diseases. These pathogenic B cell Populations can be distinguished by their surface expression of monospecific immunoglobulin. Development of a novel vector system to deliver genes to these specific B cells could improve the safety and efficacy of gene therapy. We have developed an efficient rnethod to target lentivectors to monospecific immunoglobulin-expressing cells in vitro and hi vivo. We were able to incorporate a model antigen CD20 and a fusogenic protein derived from the Sindbis virus as two distinct molecules into the lentiviral Surface. This engineered vector could specifically bind to cells expressing Surface immunoglobulin recognizing CD20 (αCD20), resulting in efficient transduction of target cells in a cognate antigen-dependent manner in vitro, and in vivo in a xenografted tumor model. Tumor suppression was observed in vivo, using the engineered lentivector to deliver a suicide gene to a xenografted tumor expressing αCD20. These results show the feasibility of engineering lentivectors to target immunoglobulin-specific cells to deliver a therapeutic effect. Such targeting lentivectors also Could potentially be used to genetically mark antigen-specific B cells in vivo to study their B cell biology