AT-752 targets multiple sites and activities on the Dengue virus replication enzyme NS5

AT-752 is a guanosine analogue prodrug active against dengue virus (DENV). In infected cells, it is metabolized into 2'-methyl-2'-fluoro guanosine 5'-triphosphate (AT-9010) which inhibits RNA synthesis in acting as a RNA chain terminator. Here we show that AT-9010 has several modes of action on DENV full-length NS5. AT-9010 does not inhibit the primer pppApG synthesis step significantly. However, AT-9010 targets two NS5-associated enzyme activities, the RNA 2'-O-MTase and the RNA-dependent RNA polymerase (RdRp) at its RNA elongation step. Crystal structure and RNA methyltransferase (MTase) activities of the DENV 2 MTase domain in complex with AT-9010 at 1.97 Å resolution shows the latter bound to the GTP/RNA-cap binding site, accounting for the observed inhibition of 2'-O but not N7-methylation activity. AT-9010 is discriminated ∼10 to 14-fold against GTP at the NS5 active site of all four DENV1-4 NS5 RdRps, arguing for significant inhibition through viral RNA synthesis termination. In Huh-7 cells, DENV1-4 are equally sensitive to AT-281, the free base of AT-752 (EC50 ≈ 0.50 μM), suggesting broad spectrum antiviral properties of AT-752 against flaviviruses.

Communicating with children about 'everyday' pain and injury: A Delphi study

BACKGROUND

'Everyday' pain experiences are potentially critical in shaping our beliefs and behaviours around injury and pain. Influenced by social, cultural and environmental contexts, they form the foundation of one's understanding of pain and injury that is taken into adulthood. How to best communicate to young children about their everyday pain experiences, in order to foster adaptive beliefs and behaviours, is unknown.

METHODS

In this Delphi survey, we sought expert opinion on the key messages and strategies that parents/caregivers can consider when communicating with young children (aged 2-7 years) about 'everyday' pain that is most likely to promote recovery, resilience and adaptive pain behaviours. Eighteen experts participated including specialists in paediatric pain, trauma, child development, and psychology; educators and parents. The survey included three rounds.

RESULTS

Response rate was over 88%. Two hundred fifty-three items were raised; 187 reached 'consensus' (≥80% agreement among experts). Key messages that the experts agreed to be 'very important' were aligned with current evidence-based understandings of pain and injury. Strategies to communicate messages included parent/caregiver role-modelling, responses to child pain, and discussion during and/or after a painful experience. Other key themes included promoting emotional development, empowering children to use active coping strategies, and resilience building.

CONCLUSIONS

This diverse set of childhood, pain and parenting experts reached consensus on 187 items, yielding 12 key themes to consider when using everyday pain experiences to promote adaptive pain beliefs and behaviours in young children.

Microplastics in beluga whale (Delphinapterus leucas) prey: An exploratory assessment of trophic transfer in the Beaufort Sea

Microplastics (MPs, <5 mm in length) have been identified as emerging contaminants in marine environments, with ingestion by a variety of biota being of increasing concern. Few studies exist on MP ingestion in Arctic fish, and there are currently no such data from the Beaufort Sea. We investigated MP abundance in five ecologically valuable species from three sampling sites in the Eastern Beaufort Sea to evaluate possible trophic-level pathways of MPs from prey to beluga whales. Polymer analysis confirmed that 21% of fish gastrointestinal tracts (n = 116) contained microplastic particles. Fish that contained MPs had a mean abundance of 1.42 ± 0.44 particles per individual and an overall mean abundance of 0.37 ± 0.16 particles. No plastic particles >5 mm were found, and 78% of the particles observed were fibers. Based on energetic needs, we estimate that individual beluga may ingest between 3800 and 145,000 microplastics annually through trophic transfer, with uncertain health implications.

Microplastics in beluga whales (Delphinapterus leucas) from the Eastern Beaufort Sea

Microplastics (MPs, particles <5 mm) represent an emerging global environmental concern, having been detected in multiple aquatic species. However, very little is known about the presence of MPs in higher trophic level species, including cetaceans. We worked with community based monitors and Inuvialuit hunters from Tuktoyaktuk (Northwest Territories, Canada) to sample seven beluga whales (Delphinapterus leucas) in 2017 and 2018. Microplastics were detected in the gastrointestinal tracts in every whale. We estimate that each whale contained 18 to 147 MPs in their GI tract (average of 97 ± 42 per individual). FTIR-spectroscopy revealed over eight plastic polymer types, with nearly half being polyester. Fibres made up 49% of MPs. The diversity of MP shapes and polymeric identities in beluga points to a complex source scenario, and ultimately raises questions regarding the significance and long-term exposure of this pollutant in this ecologically and culturally valuable species.

Post-traumatic stress symptoms in children and adolescents with chronic pain: A topical review of the literature and a proposed framework for future research

BACKGROUND AND OBJECTIVE

The co-occurrence of chronic pain and post-traumatic stress symptoms (PTSS) and post-traumatic stress disorder (PTSD) has gained increasing research attention. Studies on associations among pain and PTSS or PTSD in youth have largely been conducted in the context of acute injury or trauma. Less is known about the risk for co-occurrence with paediatric chronic pain. In this review, we (1) propose a conceptual framework to outline factors salient during childhood that may be associated with symptom severity, co-occurrence and mutual maintenance, (2) present relevant literature on PTSS in youth with acute and chronic pain and identify research gaps and (3) provide recommendations to guide paediatric research examining shared symptomatology.

DATABASES AND DATA TREATMENT

Electronic databases (PubMed and Google Scholar) were used to identify relevant articles using the search terms 'child, adolescent, paediatric, chronic pain, acute pain, post-traumatic stress symptoms and post-traumatic stress disorder'. Studies were retrieved and reviewed based on relevance to the topic.

RESULTS

Our findings revealed that existing biobehavioural and ecological models of paediatric chronic pain lack attention to traumatic events or the potential development of PTSS. Paediatric studies are also limited by lack of a conceptual framework for understanding the prevalence, risk and trajectories of PTSS in youth with chronic pain.

CONCLUSIONS

Our new developmentally informed framework highlights individual symptoms and shared contextual factors that are important when examining potential associations among paediatric chronic pain and PTSS. Future studies should consider bidirectional and mutually maintaining associations, which will be aided by prospective, longitudinal designs. WHAT DOES THIS REVIEW ADD?: This review presents relevant literature on pain and PTSS in youth and proposes a conceptual framework to examine factors salient during childhood that may be associated with symptom severity, comorbidity and mutual maintenance of chronic pain and PTSS in paediatric populations. We highlight dynamic factors that may change across children's development and provide recommendations to guide paediatric research examining potential associations among PTSS and chronic pain.

Real-time evaluation of an optimized real-time PCR assay versus Brilliance chromogenic MRSA agar for the detection of meticillin-resistant Staphylococcus aureus from clinical specimens

A total of 1204 meticillin-resistant Staphylococcus aureus (MRSA) screens (3340 individual swabs) were tested to evaluate a staphylococcal cassette chromosome mec (SCCmec) real-time PCR. In total, 148 (12.3 %) of the screens were MRSA-positive, where 146 (12.1 %) were MRSA-positive by the SCCmec real-time PCR assay. In contrast, 128 (10.6 %) screens were MRSA-positive by culture. One hundred and twenty-six (10.5 %) of the screens were positive by both culture and PCR. Twenty of the 1204 screens (1.66 %) were negative by culture but positive by PCR; these samples were sequenced. In 14 of the cases, a homology search confirmed the sequence as SCCmec, indicating that these samples could be considered true positives. Two of the 1204 (0.2 %) screens were positive by culture and negative by PCR. The mean turnaround time (TAT) for PCR-negative swabs was 6 h 12 min and for PCR-positive swabs was 6 h 48 min. In comparison, for culture-negative swabs the mean TAT was 29 h 30 min and for culture-positive swabs was 69 h. The cost per swab for routine culture was £0.41 (€0.48) and that of the real-time PCR assay was £2.35 (€2.75). This optimized, in-house, inexpensive, real-time PCR test maintained a very high sensitivity and specificity when evaluated under real-time laboratory conditions. The TAT of this real-time PCR assay was substantially lower than that of chromogenic culture. It was also maintained throughout the entire process, which can be taken as an indirect measure of test performance. This study showed that implementation of a molecular test can be achieved with limited resources in a standard microbiology laboratory.

Electrochemical destruction of p-chlorophenol and p-nitrophenol -- Influence of surfactants and anode materials

The electrochemical oxidative removal of p-chlorophenol and p-nitrophenol was studied by cyclic voltammetry (CV) and constant current electrolysis on commercially available graphite and titanium substrate insoluble anodes (TSIA). The effect of cationic cetyl trimethylammonium bromide (CTAB), anionic sodium dodecyl sulphate (SDS) and non-ionic polyoxyethylene(23)lauryl ether (Brij-35) surfactants, which prevent adherent film formation on the electrode surface were also studied. CV experiments indicate that p-chlorophenol exhibits a relatively higher tendency for film formation on graphite and that sodium chloride is a better medium for the destruction of phenols. The electrochemical oxidation of phenols under galvanostatic conditions in chloride medium with CTAB enhanced the detoxification process with significantly lower fouling effects on TSIA. The surfactants, however, did not improve phenol removal on graphite under identical experimental conditions. A charge of 2.5F per mol was found to be sufficient to achieve 44-48% removal of phenol on both the electrodes in the absence of the surfactants. A 55-65% removal was achieved in the presence of the cationic surfactant on the TSIA electrode. Phenol was removed as a low molecular weight polymer (MW approximately 4450).

The effect of structure of oil phase, surfactant and co-surfactant on the physicochemical and electrochemical properties of bicontinuous microemulsion

Efforts were made to prepare bicontinuous microemulsions with ten different oil phases involving aliphatic, linear, and aromatic hydrocarbons as oil phases, two co-surfactants (n-butanol and n-pentanol) and two surfactants: cationic (CTAB) and anionic (SDS). Different weight percentages were employed for the preparation of cationic and anionic surfactant based microemulsions as reported in the literature. Out of the 40 compositions (10 oil phasesx2 co-surfactantsx2 surfactants) thus selected only 28 systems showed stable bicontinuous microemulsion phase. This behavior is explained on the basis of the structures of various constituents present in the microemulsions. Viscosity variations of stable bicontinuous microemulsions are found to depend mainly on the nature of co-surfactant. Conductivity behavior on the other hand depends mainly on the weight percentage and composition of aqueous phase. The solubility of pyrene in the oil phase determines the excimer formation and fluorescence behavior in microemulsions. The electron transfer property of both the water-soluble and the oil-soluble redox systems does not depend on the oil phase and the co-surfactant. The significance and importance of characterizing well defined bicontinuous microemulsions is thus highlighted.