The structure of the hexameric atrazine chlorohydrolase AtzA

Atrazine chlorohydrolase (AtzA) was discovered and purified in the early 1990s from soil that had been exposed to the widely used herbicide atrazine. It was subsequently found that this enzyme catalyzes the first and necessary step in the breakdown of atrazine by the soil organism Pseudomonas sp. strain ADP. Although it has taken 20 years, a crystal structure of the full hexameric form of AtzA has now been obtained. AtzA is less well adapted to its physiological role (i.e. atrazine dechlorination) than the alternative metal-dependent atrazine chlorohydrolase (TrzN), with a substrate-binding pocket that is under considerable strain and for which the substrate is a poor fit

A Preliminary Study on the Efficacy of a Community-Based Physical Activity Intervention on Physical Function-Related Risk Factors for Falls among Breast Cancer Survivors

Objective The aim of this study was to examine the effects of a 6-week community-based physical activity (PA) intervention on physical function-related risk factors for falls among 56 breast cancer survivors (BCS) who had completed treatments. Design This was a single-group longitudinal study. The multimodal PA intervention included aerobic, strengthening and balance components. Physical function outcomes based on the 4-meter walk, chair stand, one-leg stance, tandem walk, and dynamic muscular endurance tests were assessed at 6-week pre-intervention (T1), baseline (T2), and post-intervention (T3). T1-T2 and T2-T3 were the control and intervention periods, respectively. Results All outcomes, except the tandem walk test, significantly improved after the intervention period (p 0.05). Based on the falls risk criterion in the one-leg stance test, the proportion at risk for falls was significantly lower after the intervention period (p = 0.04), but not after the control period. Conclusions A community-based multimodal PA intervention for BCS may be efficacious in improving physical function-related risk factors for falls, and lowering the proportion of BCS at risk for falls based on specific physical function-related falls criteria. Further larger trials are needed to confirm these preliminary findings

Relationship between Temperament and Performance Traits in Yearling Cattle

To examine relationships between exit velocity (EV, objective measure of temperament) and performance traits, calves were weighed 14 days prior to weaning, at weaning, 128 days post weaning, and at time of carcass measurements. Exit velocity obtained on day -14 and carcass ultrasound measurements (n = 6) obtained on day 208 and carcass harvest measurements (n = 12) obtained on day 349 were used to determine correlations between EV, performance and carcass measurements. Exit velocity showed a tendency to be negatively correlated (P \u3c 0.15) with weaning weight (r = -0.40), but not correlated (P \u3e 0.05) with average daily gain post 128 days. Exit velocity was not correlated (P \u3e 0.05) with carcass ultrasound measurements or with yearling weight. Exit velocity was negatively correlated (P = 0.04) with carcass weight (r = -0.65). Although, EV was not correlated (P \u3c 0.05) with carcass harvest traits of back fat and longissimus muscle area, results indicated more excitable cattle could have less back fat and smaller longissimus muscle area. Results suggest with additional numbers EV may be useful as an objective measure of temperament to sort calves into specific outcome groups that differ in carcass quality traits

Maintained hand function and forearm bone health 14 months after an in-home virtual-reality videogame hand telerehabilitation intervention in an adolescent with hemiplegic cerebral palsy

Virtual reality videogames can be used to motivate rehabilitation, and telerehabilitation can be used to improve access to rehabilitation. These uses of technology to improve health outcomes are a burgeoning area of rehabilitation research. So far, there is a lack of reports of long-term outcomes of these types of interventions. The authors report a 15-year-old boy with hemiplegic cerebral palsy and epilepsy because of presumed perinatal stroke who improved his plegic hand function and increased his plegic forearm bone health during a 14-month virtual reality videogame hand telerehabilitation intervention. A total of 14 months after the intervention ended, repeat evaluation demonstrated maintenance of both increased hand function and forearm bone health. The implications of this work for the future of rehabilitation in children with neurological disabilities are discussed in this article

Achilles tendon material properties are greater in the jump leg of jumping athletes

Purpose: The Achilles tendon (AT) must adapt to meet changes in demands. This study explored AT adaptation by comparing properties within the jump and non-jump legs of jumping athletes. Non-jumping control athletes were included to control limb dominance effects. Methods: AT properties were assessed in the preferred (jump) and non-preferred (lead) jumping legs of male collegiate-level long and/or high jump (jumpers; n=10) and cross-country (controls; n=10) athletes. Cross-sectional area (CSA), elongation, and force during isometric contractions were used to estimate the morphological, mechanical and material properties of the ATs bilaterally. Results: Jumpers exposed their ATs to more force and stress than controls (all p≤0.03). AT force and stress were also greater in the jump leg of both jumpers and controls than in the lead leg (all p0.05). Conclusion: ATs chronically exposed to elevated mechanical loading were found to exhibit greater mechanical (stiffness) and material (Young’s modulus) properties

Progressive skeletal benefits of physical activity when young as assessed at the midshaft humerus in male baseball players

Physical activity benefits the skeleton, but there is contrasting evidence regarding whether benefits differ at different stages of growth. The current study demonstrates that physical activity should be encouraged at the earliest age possible and be continued into early adulthood to gain most skeletal benefits. INTRODUCTION: The current study explored physical activity-induced bone adaptation at different stages of somatic maturity by comparing side-to-side differences in midshaft humerus properties between male throwing athletes and controls. Throwers present an internally controlled model, while inclusion of control subjects removes normal arm dominance influences. METHODS: Throwing athletes (n = 90) and controls (n = 51) were categorized into maturity groups (pre, peri, post-early, post-mid, and post-late) based on estimated years from peak height velocity (10 years). Side-to-side percent differences in midshaft humerus cortical volumetric bone mineral density (Ct.vBMD) and bone mineral content (Ct.BMC); total (Tt.Ar), medullary (Me.Ar), and cortical (Ct.Ar) areas; average cortical thickness (Ct.Th); and polar Strength Strain Index (SSIP) were assessed. RESULTS: Significant interactions between physical activity and maturity on side-to-side differences in Ct.BMC, Tt.Ar, Ct.Ar, Me.Ar, Ct.Th, and SSIP resulted from the following: (1) greater throwing-to-nonthrowing arm differences than dominant-to-nondominant arm differences in controls (all p < 0.05) and (2) throwing-to-nonthrowing arm differences in throwers being progressively greater across maturity groups (all p < 0.05). Regional analyses revealed greatest adaptation in medial and lateral sectors, particularly in the three post-maturity groups. Years throwing predicted 59% of the variance of the variance in throwing-to-nonthrowing arm difference in SSIP (p < 0.001). CONCLUSION: These data suggest that physical activity has skeletal benefits beginning prior to and continuing beyond somatic maturation and that a longer duration of exposure to physical activity has cumulative skeletal benefits. Thus, physical activity should be encouraged at the earliest age possible and be continued into early adulthood to optimize skeletal benefits

The Redox Cofactor F-420 Protects Mycobacteria from Diverse Antimicrobial Compounds and Mediates a Reductive Detoxification System

A defining feature of mycobacterial redox metabolism is the use of an unusual deazaflavin cofactor, F420. This cofactor enhances the persistence of environmental and pathogenic mycobacteria, including after antimicrobial treatment, although the molecular basis for this remains to be understood. In this work, we explored our hypothesis that F420 enhances persistence by serving as a cofactor in antimicrobial-detoxifying enzymes. To test this, we performed a series of phenotypic, biochemical, and analytical chemistry studies in relation to the model soil bacterium Mycobacterium smegmatis. Mutant strains unable to synthesize or reduce F420 were found to be more susceptible to a wide range of antibiotic and xenobiotic compounds. Compounds from three classes of antimicrobial compounds traditionally resisted by mycobacteria inhibited the growth of F420 mutant strains at subnanomolar concentrations, namely, furanocoumarins (e.g., methoxsalen), arylmethanes (e.g., malachite green), and quinone analogues (e.g., menadione). We demonstrated that promiscuous F420H2-dependent reductases directly reduce these compounds by a mechanism consistent with hydride transfer. Moreover, M. smegmatis strains unable to make F420H2 lost the capacity to reduce and detoxify representatives of the furanocoumarin and arylmethane compound classes in whole-cell assays. In contrast, mutant strains were only slightly more susceptible to clinical antimycobacterials, and this appeared to be due to indirect effects of F420 loss of function (e.g., redox imbalance) rather than loss of a detoxification system. Together, these data show that F420 enhances antimicrobial resistance in mycobacteria and suggest that one function of the F420H2-dependent reductases is to broaden the range of natural products that mycobacteria and possibly other environmental actinobacteria can reductively detoxify

Functional polymorphisms in the P2X7 receptor gene are associated with stress fracture injury

Context: Military recruits and elite athletes are susceptible to stress fracture injuries. Genetic predisposition has been postulated to have a role in their development. The P2X7 receptor (P2X7R) gene, a key regulator of bone remodelling, is a genetic candidate that may contribute to stress fracture predisposition. Objective: To evaluate the putative contribution of P2X7R to stress fracture injury in two separate cohorts, military personnel and elite athletes. Methods: In 210 Israeli Defence Forces (IDF) military conscripts, stress fracture injury was diagnosed (n=43) based on symptoms and a positive bone scan. In a separate cohort of 518 elite athletes, self-reported medical imaging scan-certified stress fracture injuries were recorded (n=125). Non-stress fracture controls were identified from these cohorts who had a normal bone scan or no history or symptoms of stress fracture injury. Study participants were genotyped for functional SNPs within the P2X7R gene using proprietary fluorescence-based competitive allele-specific PCR assay. Pearson Chi-square (χ2) tests, corrected for multiple comparisons, were used to assess associations in genotype frequencies. Results: The variant allele of P2X7R SNP rs3751143 (Glu496Ala- loss of function) was associated with stress fracture injury, while the variant allele of rs1718119 (Ala348Thr- gain of function) was associated with a reduced occurrence of stress fracture injury in military conscripts (P<0.05). The association of the variant allele of rs3751143 with stress fractures was replicated in elite athletes (P<0.05), whereas the variant allele of rs1718119 was also associated with reduced multiple stress fracture cases in elite athletes (P<0.05). Conclusions: The association between independent P2X7R polymorphisms with stress fracture prevalence supports the role of a genetic predisposition in the development of stress fracture injury

The vulnerability of public spaces: challenges for UK hospitals under the 'new' terrorist threat

This article considers the challenges for hospitals in the United Kingdom that arise from the threats of mass-casualty terrorism. Whilst much has been written about the role of health care as a rescuer in terrorist attacks and other mass-casualty crises, little has been written about health care as a victim within a mass-emergency setting. Yet, health care is a key component of any nation's contingency planning and an erosion of its capabilities would have a significant impact on the generation of a wider crisis following a mass-casualty event. This article seeks to highlight the nature of the challenges facing elements of UK health care, with a focus on hospitals both as essential contingency responders under the United Kingdom's civil contingencies legislation and as potential victims of terrorism. It seeks to explore the potential gaps that exist between the task demands facing hospitals and the vulnerabilities that exist within them