Risk-Taking in Disorders of Natural and Drug Rewards: Neural Correlates and Effects of Probability,Valence, and Magnitude

Pathological behaviors toward drugs and food rewards have underlying commonalities. Risk-taking has a fourfold pattern varying as a function of probability and valence leading to the nonlinearity of probability weighting with overweighting of small probabilities and underweighting of large probabilities. Here we assess these influences on risk-taking in patients with pathological behaviors toward drug and food rewards and examine structural neural correlates of nonlinearity of probability weighting in healthy volunteers. In the anticipation of rewards, subjects with binge eating disorder show greater risk-taking, similar to substance-use disorders. Methamphetamine-dependent subjects had greater nonlinearity of probability weighting along with impaired subjective discrimination of probability and reward magnitude. Ex-smokers also had lower risk-taking to rewards compared with non-smokers. In the anticipation of losses, obesity without binge eating had a similar pattern to other substance-use disorders. Obese subjects with binge eating also have impaired discrimination of subjective value similar to that of the methamphetamine-dependent subjects. Nonlinearity of probability weighting was associated with lower gray matter volume in dorsolateral and ventromedial prefrontal cortex and orbitofrontal cortex in healthy volunteers. Our findings support a distinct subtype of binge eating disorder in obesity with similarities in risk-taking in the reward domain to substance use disorders. The results dovetail with the current approach of defining mechanistically based dimensional approaches rather than categorical approaches to psychiatric disorders. The relationship to risk probability and valence may underlie the propensity toward pathological behaviors toward different types of rewards.     

Use of Faropenem as an Indicator of Carbapenemase Activity in the Enterobacteriaceae

The aim of this study was to determine the ability of a disc susceptibility test using faropenem (10 μg) to predict carbapenemase activity in Enterobacteriaceae. A collection of 166 isolates of carbapenemase-producing Enterobacteriaceae (CPE) and 82 isolates of Enterobacteriaceae that produced other β-lactamases was compiled from diverse sources. Disc susceptibility testing was performed using the CLSI/EUCAST methodology with discs of faropenem (10 μg), temocillin (30 μg), and four carbapenems (each 10 μg). A further prospective evaluation of the faropenem disc susceptibility test was performed using 205 consecutive isolates referred to a United Kingdom reference laboratory in parallel with molecular methods for carbapenemase detection. Of 166 isolates of CPE, 99% showed growth up to the edge of a 10-μg faropenem disc compared with only 6% of other β-lactamase producers (sensitivity, 99%; specificity, 94%). A “double zone” around 10-μg faropenem discs was frequently associated with OXA-48 producers. Of the carbapenems, the most useful agent was imipenem, where a zone diameter of ≤23 mm as a predictor of carbapenemase activity had a sensitivity of 99% and a specificity of 85%. The presence of no zone of inhibition around a 30-μg temocillin disc was a consistent feature of strains producing OXA-48 carbapenemase. For 205 isolates of Enterobacteriaceae referred to a United Kingdom reference laboratory, growth up to a 10-μg faropenem disc correctly identified 84 of 86 carbapenemase producers (98% sensitivity), with a specificity of 87%. Disc susceptibility testing using faropenem (10 μg) is a simple, convenient, and highly predictive screening test for carbapenemase-producing Enterobacteriaceae.     

Changes in exertion-related symptoms in adults and youth who have sustained a sport-related concussion

ObjectivesTo identify the symptoms responsible for cessation of exercise testing and evaluate changes in post-concussion symptom scores on the Post-Concussion Symptom Scale (PCSS) from the Sport-Concussion Assessment Tool (SCAT5) immediately, 1–4 h, and 6–12 h following completion of the Buffalo Concussion Treadmill Test (BCTT) in youth and adults who have sustained a sport-related concussion.DesignProspective case-series.MethodsIndividuals who were diagnosed with a sport-related concussion and self-reported difficulties with exertion were referred to perform an exertional treadmill test. Individuals were recruited from a university sports medicine clinic. Change in PCSS symptom severity scores were operationally defined as a change ≥4 points.ResultsForty-five individuals aged 13–57 years consented to participate. A total of 14/24 (58.3%) female and 13/21 (61.9%) male participants reported an increase in symptom severity scores immediately following the BCTT. At 1–4 h, 5/10 (50.0%) males and 5/14 (35.7%) females who completed the PCSS had elevated symptom severity scores compared to pre-exertion. Only 24.2% (3/17 males and 5/16 females) of participants completing the PCSS at 6–12 h reported increased symptom severity scores.ConclusionExertional testing is an important component of a multifaceted assessment following concussion; however, previous research evaluating symptom responses to exertion is limited. This study provides evidence to suggest individuals who experience an exacerbation of concussion-associated symptoms after exertion are likely to return to pre-exertion levels within the same day. Future research monitoring symptoms following exertion and throughout recovery should be performed in tandem with physiological measures to better understand the source of symptoms.     

Assessment of IGRT variability for lung SBRT

PurposeThe purpose of this project was to assess factors that may influence variability in the pre-treatment kilovoltage cone beam computed tomography (kV CBCT) image matching process for lung stereotactic body radiation therapy (SBRT).Methods and materialsPre-treatment CBCT and planning CT data sets of previously-treated lung SBRT patients were gathered and anonymized from four radiotherapy centers in Alberta. Eight radiation therapists (RTTs) and four radiation oncologists (ROs) were recruited from the same four cancer centers for image matching. Identical data sets were provided to each user, but the order of image sets was randomized independently for each user to remove any learning bias. Inter-user variabilities were then investigated as functions of various factors, including image origin (source institution/machine), user's institution (local matching protocol), profession (RTT vs. RO), years of experience and image quality (presence/absence of added noise).ResultsVery little variation in image matching between different users was observed. The mean differences from the consensus means for different image sets were less than 1 mm in all directions, and cases that exceeded 3 mm (i.e. clinically significant differences) were extremely rare. Image origin, user's institution, and profession (RTT vs. RO) didn't lead to any meaningful clinical differences, while image quality didn't introduce any statistically significant differences. In addition, no discernible trend was seen between user's experience and deviation from the user mean. Overall, no meaningful differences in inter-user variabilities for the different factors investigated were found in this study.ConclusionsThere appears to be an adequate standardization across the province of Alberta in terms of CBCT image matching process. No clinically significant differences were observed as functions of various factors investigated in this study. Consistency in matching between RTTs and ROs in this study suggests that RTTs do not need systematic RO approval of their lung CBCT match. It should be noted that RTTs at the centers in this study receive comprehensive training in CBCT-based image matching.     

From the Cover: Supercell tornadoes are much stronger and wider than damage-based ratings indicate

Tornadoes cause damage, injury, and death when intense winds impact structures. Quantifying the strength and extent of such winds is critical to characterizing tornado hazards. Ratings of intensity and size are based nearly entirely on postevent damage surveys [R. Edwards et al., Bull. Am. Meteorol. Soc. 94, 641–653 (2013)]. It has long been suspected that these suffer low bias [C. A. Doswell, D. W. Burgess, Mon. Weather Rev. 116, 495–501 (1988)]. Here, using mapping of low-level tornado winds in 120 tornadoes, we prove that supercell tornadoes are typically much stronger and wider than damage surveys indicate. Our results permit an accurate assessment of the distribution of tornado intensities and sizes and tornado wind hazards, based on actual wind-speed observations, and meaningful comparisons of the distribution of tornado intensities and sizes with theoretical predictions. We analyze data from Doppler On Wheels (DOW) radar measurements of 120 tornadoes at the time of peak measured intensity. In striking contrast to conventional damage-based climatologies, median tornado peak wind speeds are ∼60 m⋅s⁻¹, capable of causing significant, Enhanced Fujita Scale (EF)-2 to -3, damage, and 20% are capable of the most intense EF-4/EF-5 damage. National Weather Service (NWS) EF/wind speed ratings are 1.2 to 1.5 categories (∼20 m⋅s⁻¹) lower than DOW observations for tornadoes documented by both the NWS and DOWs. Median tornado diameter is 250 to 500 m, with 10 to 15% >1 km. Wind engineering tornado-hazard-model predictions and building wind resistance standards may require upward adjustment due to the increased wind-damage risk documented here.

Tornadoes cause direct harm to people, infrastructure, and communities (1). Quantifying tornado risk requires accurate knowledge of their wind speeds and the size of the areas at risk from these intense winds. However, since direct measurements of tornado winds are rare, tornado intensity and size are nearly always inferred indirectly from postevent damage surveys applying the Fujita (F) or Enhanced Fujita (EF) scales (2–5) to infer maximum wind speeds. Statistics concerning tornado frequency, intensity, and size are derived from these surveys. However, because most tornadoes do not damage well-engineered structures, from which the most intense wind speeds can be inferred, and many occur in primarily rural areas, damage-based tornado wind speed and size estimations are likely severely low biased (6–11). A limited climatology (12), using Doppler On Wheels (DOW) radar data (13–15), suggested that tornadoes may be larger and more intense than indicated by these surveys. In-situ observations of wind speeds reliably demonstrable to be inside the radius of maximum winds of tornadoes are very rare (16, 17) and inadequate for deriving a statistically meaningful climatology. It is no exaggeration to state that, until now, statistics concerning even the most basic characteristics of tornadoes, including intensity and size, could not be quantified with confidence.