Structure-guided mutagenesis of OSCAs reveals differential activation to mechanical stimuli

The dimeric two-pore OSCA/TMEM63 family has recently been identified as mechanically activated ion channels. Previously, based on the unique features of the structure of OSCA1.2, we postulated the potential involvement of several structural elements in sensing membrane tension1. Interestingly, while OSCA1, 2, and 3 clades are activated by membrane stretch in cell-attached patches (i.e., they are stretch-activated channels), they differ in their ability to transduce membrane deformation induced by a blunt probe (poking). In an effort to understand the domains contributing to mechanical signal transduction, we used cryo-electron microscopy to solve the structure of Arabidopsis thaliana (At) OSCA3.1, which, unlike AtOSCA1.2, only produced stretch- but not poke-activated currents in our initial characterization2. Mutagenesis and electrophysiological assessment of conserved and divergent putative mechanosensitive features of OSCA1.2 reveal a selective disruption of the macroscopic currents elicited by poking without considerable effects on stretch-activated currents (SAC). Our results support the involvement of the amphipathic helix and lipid-interacting residues in the membrane fenestration in the response to poking. Our findings position these two structural elements as potential sources of functional diversity within the family.

In praise of postgraduate career clinics: Translating health professionals' willingness to engagement

AIM

To capture and retain healthcare staff in postgraduate courses relevant to individual career aspirations, service requirements and continuous practice development (CPD) within an English UK university.

DESIGN

Two virtual career clinics for postgraduate practitioners to engage in CPD offers within the university. An online post-enrolment online survey to explore their experiences of engagement with the university.

METHODS

Mixed: qualitative and quantitative methods. Engaging 10 participants attended the career clinics, and 42 participants with an online survey.

RESULTS

The career clinics were well received by participants who mapped CPD requirements and individual career aspirations. The surveys exposed challenges with marketing and enrolment; however, these were mitigated with support. Four recommendations are presented within this paper applicable to the international postgraduate education of all health practitioners.

Effect of verbal instructions on trunk muscle activity during volitional preemptive abdominal contraction

OBJECTIVE

This study investigated the effect of Verbal Instruction (VI) strategies on trunk muscle contraction among healthy subjects. The effect of three VI Abdominal Drawing-In Maneuver (ADIM) and two VI Abdominal Bracing Maneuver (ABM) strategies on left Internal (LIO) and External Oblique (LEO) and bilateral superficial Multifidi (sMf) activation was examined.

DESIGN

Within-subjects, repeated measure design.

METHODS

Surface EMG (sEMG) measured LIO, LEO, and sMf activity in 28 subjects (mean age 23.5 ± 5.5 years). Testing included five supine hook-lying and five quiet standing conditions.

RESULTS

One-way ANOVAs demonstrated no significant main effect for ADIM or ABM in supine or standing (p > .05). Muscle activation amplitudes during VPAC conditions demonstrated higher mean values for standing versus supine (p < .05) except for two conditions involving LEO. Friedman Tests for dominant strategy demonstrated a significant main effect for ADIM-VI and ABM-VI strategies. Post-hoc testing generally showed the dominant strategy to be significantly higher versus others.

CONCLUSION

No single preferred VI cue for ADIM or ABM was observed. Each subject's dominant strategy dictated the most suitable VI. Standing was preferred for LIO and sMf activation, whereas position did not change LEO activation. Non-significant correlations between all muscle pairings during all ADIM and ABM strategies were observed. These findings may suggest the need for healthcare providers who understand the intricacies of trunk stability to teach and monitor VPAC with either ADIM or ABM options.

Mapping Single-Molecule Protein Complexes in 3D with DNA Nanoswitch Calipers

The ability to accurately map the 3D geometry of single-molecule complexes in trace samples is a challenging goal that would lead to new insights into molecular mechanics and provide an approach for single-molecule structural proteomics. To enable this, we have developed a high-resolution force spectroscopy method capable of measuring multiple distances between labeled sites in natively folded protein complexes. Our approach combines reconfigurable nanoscale devices, we call DNA nanoswitch calipers, with a force-based barcoding system to distinguish each measurement location. We demonstrate our approach by reconstructing the tetrahedral geometry of biotin-binding sites in natively folded streptavidin, with 1.5-2.5 Å agreement with previously reported structures.

Elevated plasma matrix metalloproteinases associate with Mycobacterium tuberculosis blood stream infection and mortality in HIV-associated tuberculosis

Mortality from HIV-associated tuberculosis (HIV-TB) is high, particularly among hospitalised patients. In 433 people living with HIV admitted to hospital with symptoms of TB, we investigated plasma matrix metalloproteinases (MMP) and matrix-derived biomarkers in relation to TB diagnosis, mortality and Mycobacterium tuberculosis (Mtb) blood stream infection (BSI). Compared to other diagnoses, MMP-8 was elevated in confirmed TB and in Mtb-BSI, positively correlating with extracellular matrix breakdown products. Baseline MMP-3, -7, -8, -10 and procollagen III N-terminal propeptide (PIIINP) associated with Mtb-BSI and 12-week mortality. These findings implicate MMP dysregulation in pathophysiology of advanced HIV-TB and support MMP inhibition as a host-directed therapeutic strategy for HIV-TB.

Real-world utilization of guideline-directed genetic testing in inherited cardiovascular diseases

Background

Cardiovascular disease continues to be the leading cause of death globally. Clinical practice guidelines aimed at improving disease management and positively impacting major cardiac adverse events recommend genetic testing for inherited cardiovascular conditions such as dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), long QT syndrome (LQTS), hereditary amyloidosis, and familial hypercholesterolemia (FH); however, little is known about how consistently practitioners order genetic testing for these conditions in routine clinical practice. This study aimed to assess the adoption of guideline-directed genetic testing for patients diagnosed with DCM, HCM, LQTS, hereditary amyloidosis, or FH.

Methods

This retrospective cohort study captured real-world evidence of genetic testing from ICD-9-CM and ICD-10-CM codes, procedure codes, and structured text fields of de-identified patient records in the Veradigm Health Insights Ambulatory EHR Research Database linked with insurance claims data. Data analysis was conducted using an automated electronic health record analysis engine. Patient records in the Veradigm database were sourced from more than 250,000 clinicians serving over 170 million patients in outpatient primary care and specialty practice settings in the United States and linked insurance claims data from public and private insurance providers. The primary outcome measure was evidence of genetic testing within six months of condition diagnosis.

Results

Between January 1, 2017, and December 31, 2021, 224,641 patients were newly diagnosed with DCM, HCM, LQTS, hereditary amyloidosis, or FH and included in this study. Substantial genetic testing care gaps were identified. Only a small percentage of patients newly diagnosed with DCM (827/101,919; 0.8%), HCM (253/15,507; 1.6%), LQTS (650/56,539; 1.2%), hereditary amyloidosis (62/1,026; 6.0%), or FH (718/49,650; 1.5%) received genetic testing.

Conclusions

Genetic testing is underutilized across multiple inherited cardiovascular conditions. This real-world data analysis provides insights into the delivery of genomic healthcare in the United States and suggests genetic testing guidelines are rarely followed in practice.

Deep learning in wastewater treatment: a critical review

Modeling wastewater processes supports tasks such as process prediction, soft sensing, data analysis and computer assisted design of wastewater systems. Wastewater treatment processes are large, complex processes, with multiple controlling mechanisms, a high degree of disturbance variability and non-linear (generally stable) behavior with multiple internal recycle loops. Semi-mechanistic biochemical models currently dominate research and application, with data-driven deep learning models emerging as an alternative and supplementary approach. But these modeling approaches have grown in separate communities of research and practice, and so there is limited appreciation of the strengths, weaknesses, contrasts and similarities between the methods. This review addresses that gap by providing a detailed guide to deep learning methods and their application to wastewater process modeling. The review is aimed at wastewater modeling experts who are familiar with established mechanistic modeling approach, and are curious about the opportunities and challenges afforded by deep learning methods. We conclude with a discussion and needs analysis on the value of different ways of modeling wastewater processes and open research problems.

Advancing beyond the Hippocampus to Preserve Cognition for Patients with Brain Metastases: Dosimetric Results from a Phase 2 Trial of Memory-Avoidance Whole Brain Radiotherapy

PURPOSE/OBJECTIVE(S)

Recent advances to preserve neurocognitive function in patients treated for brain metastases include stereotactic radiosurgery (SRS), hippocampal avoidance whole brain radiation therapy (HA-WBRT), and memantine administration. However, 23% of patients receiving HA-WBRT and memantine on NRG-CC001 still experienced executive function deterioration at 4 months, with 12% experiencing total recall and delayed recognition deterioration at 6 months. The hippocampus, corpus callosum, fornix, and amygdala are key neurocognitive substructures with a low propensity for brain metastases. Herein, we report our preliminary experience using an advanced "memory-avoidance" WBRT (MA-WBRT) approach sparing these substructures for patients with multiple (>15) brain metastases.

MATERIALS/METHODS

Ten consecutive patients treated with MA-WBRT on a phase 2 clinical trial (OSU-21074) were reviewed. In each patient, the hippocampi, amygdalae, corpus callosa, and fornix were contoured. Patients were not eligible for MA-WBRT if they had metastases in these substructures. A memory- avoidance region created using a 5mm volumetric expansion around these substructures. Hotspots were avoided in the hypothalamus and pituitary gland. Dose constraints for these avoidance structures were modeled after NRG CC-001 and include a D100% ≤ 9 Gy and a D0.03 cc ≤ 16 (acceptable to 20 Gy). Coverage of brain metastases was prioritized over memory avoidance dose constraints. Linac-based volumetric modulated arc therapy (VMAT) plans were generated for a prescription dose of 30 Gy in 10 fractions.

RESULTS

On average, the memory avoidance structure volume was 37.1 ccs (Range: 25.2-44.6 ccs), occupying 2.5% of the entire whole brain target volume. All treatment plans met the D100% dose constraint, and 8/10 plans met the D0.03cc constraint, with priority given to tumor coverage for the remaining 2 cases. VMAT spared the memory avoidance structures with a median dose range of 10.8-14.2 Gy and a maximum dose (D0.03cc) range of 15.6-22.7 Gy. The mean dose to the memory avoidance structures was 12.7 Gy (Range: 11.5-13.8 Gy). Target coverage (D98% > 25 Gy) and homogeneity (D2% ≤ 37.5 Gy) were achieved for all plans.

CONCLUSION

Modern VMAT techniques allow for sparing of the hippocampus, amygdala, corpus callosum, and fornix with good target coverage and homogeneity. Prospective quality of life and cognitive data including are being collected and include the Functional Assessment of Cancer Therapy - Brain (Fact-Br), Hopkins Verbal Learning Test (HLVT-R), Trail Making Test A/B (TMT-A/B) and Controlled Oral Word Association Test (COWAT). After enrollment is completed, these data will be evaluated to assess the efficacy of MA-WBRT to mitigate declines in quality of life and cognition after whole brain radiation.

Higher Temperatures in Socially Vulnerable US Communities Increasingly Limit Safe Use of Electric Fans for Cooling

As the globe warms, people will increasingly need affordable, safe methods to stay cool and minimize the worst health impacts of heat exposure. One of the cheapest cooling methods is electric fans. Recent research has recommended ambient air temperature thresholds for safe fan use in adults. Here we use hourly weather reanalysis data (1950-2021) to examine the temporal and spatial evolution of ambient climate conditions in the continental United States (CONUS) considered safe for fan use, focusing on high social vulnerability index (SVI) regions. We find that although most hours in the day are safe for fan use, there are regions that experience hundreds to thousands of hours per year that are too hot for safe fan use. Over the last several decades, the number of hours considered unsafe for fan use has increased across most of the CONUS (on average by ∼70%), with hotspots across the US West and South, suggesting that many individuals will increasingly need alternative cooling strategies. People living in high-SVI locations are 1.5-2 times more likely to experience hotter climate conditions than the overall US population. High-SVI locations also experience higher rates of warming that are approaching and exceeding important safety thresholds that relate to climate adaptation. These results highlight the need to direct additional resources to these communities for heat adaptive strategies.

The Association Between Central Line-Associated Bloodstream Infection and Central Line Access

OBJECTIVES

Identifying modifiable risk factors associated with central line-associated bloodstream infections (CLABSIs) may lead to modifications to central line (CL) management. We hypothesize that the number of CL accesses per day is associated with an increased risk for CLABSI and that a significant fraction of CL access may be substituted with non-CL routes.

DESIGN

We conducted a retrospective cohort study of patients with at least one CL device day from January 1, 2015, to December 31, 2019. A multivariate mixed-effects logistic regression model was used to estimate the association between the number of CL accesses in a given CL device day and prevalence of CLABSI within the following 3 days.

SETTING

A 395-bed pediatric academic medical center.

PATIENTS

Patients with at least one CL device day from January 1, 2015, to December 31, 2019.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

There were 138,411 eligible CL device days across 6,543 patients, with 639 device days within 3 days of a CLABSI (a total of 217 CLABSIs). The number of per-day CL accesses was independently associated with risk of CLABSI in the next 3 days (adjusted odds ratio, 1.007; 95% CI, 1.003-1.012; p = 0.002). Of medications administered through CLs, 88% were candidates for delivery through a peripheral line. On average, these accesses contributed a 6.3% increase in daily risk for CLABSI.

CONCLUSIONS

The number of daily CL accesses is independently associated with risk of CLABSI in the next 3 days. In the pediatric population examined, most medications delivered through CLs could be safely administered peripherally. Efforts to reduce CL access may be an important strategy to include in contemporary CLABSI-prevention bundles.

Phenological phase affects carrot seed production sensitivity to climate change - A panel data analysis

New Zealand is a major producer of carrot seeds globally. Carrots are an important nutritional crop for human consumption. Since the growth and development of carrot seed crops mainly depend on climatic factors, seed yield is extremely susceptible to climate change. This modeling study was undertaken using a panel data approach to determine the impact of the atmospheric conditions (proxied by maximum and minimum temperature) and precipitation during the critical growth stages for seed production in carrot, viz., juvenile phase, vernalization phase, floral development phase, and flowering and seed development phase on carrot seed yield. The panel dataset was created using cross-sections from 28 locations within the Canterbury and Hawke's Bay regions of New Zealand that cultivate carrot seed crops and time series from 2005 to 2022. Pre-diagnostic tests were performed to test the model assumptions, and a fixed effect model was selected subsequently. There was significant (p < 0.01) variability in temperature and rainfall throughout different growing phases, except for precipitation at the vernalization phase. The highest rate of changes in maximum temperature, minimum temperature, and precipitation were recorded during the vernalization phase (+0.254 °C per year), floral development phase (+0.18 °C per year), and juvenile phase (-6.508 mm per year), respectively. Based on marginal effect analysis, the highest significant influence of minimum (187.724 kg/ha of seed yield decrease for each 1 °C increment) and maximum temperature (1 °C rise increases seed yield by 132.728 kg/ha), and precipitation (1 mm increment of rainfall decreases the seed yield by 1.745 kg/ha) on carrot seed yield were reported at vernalization, and flowering and seed development, respectively. The minimum and maximum temperatures have a higher marginal effect on carrot seed production. Analysis of the panel data demonstrates that the production of carrot seeds will be vulnerable to climatic change.

Taming the white bear: Lowering reactance pressures enhances thought suppression

Individuals fail to suppress certain thoughts, especially under conditions that tax cognitive resources. We investigated the impact of modifying psychological reactance pressures on thought suppression attempts. Participants were asked to suppress thoughts of a target item under standard experimental conditions or under conditions designed to lower reactance pressures. In the presence of high cognitive load, weakening associated reactance pressures resulted in greater success at suppression. The results suggest that reducing relevant motivational pressures can facilitate thought suppression, even when an individual experiences cognitive limitation.

The COVID-19 pandemic's impact on all-cause mortality disparities in Medicare: By race, income, chronic health, mental/behavioral health, disability

BACKGROUND

The Medicare-enrolled population is heterogeneous across race, ethnicity, age, dual eligibility, and a breadth of chronic health, mental and behavioral health, and disability-related conditions, which may be differentially impacted by the COVID-19 pandemic.

OBJECTIVE

To quantify changes in all-cause mortality prior-to and in the first year of the COVID-19 pandemic across Medicare's different sociodemographic and health-condition subpopulations.

METHODS

This observational, population-based study used stratified bivariate regression to investigate Medicare fee-for-service subpopulation differences in pre-pandemic (i.e., 2019 versus 2016) and pandemic-related (2020 versus 2019) changes in all-cause mortality.

RESULTS

All-cause mortality in the combined Medicare-Advantage (i.e., managed care) and fee-for-service beneficiary population improved by a relative 1% in the ten years that preceded the COVID-19 pandemic, but then escalated by a relative 15.9% in 2020, the pandemic's first year. However, a closer look at Medicare's fee-for-service subpopulations reveals critical differences. All-cause mortality had actually been worsening prior to the pandemic among most psychiatric and disability-related condition groups, all race and ethnicity groups except White Non-Hispanic, and Medicare-Medicaid dual-eligible (i.e., low-income) beneficiaries. Many of these groups then experienced all-cause mortality spikes in 2020 that were over twice that of the overall Medicare fee-for-service population. Of all 61 chronic health conditions studied, beneficiaries with schizophrenia were the most adversely affected, with all-cause mortality increasing 38.4% between 2019 and 2020.

CONCLUSION

This analysis reveals subpopulation differences in all-cause mortality trends, both prior to and in year-one of the COVID-19 pandemic, indicating that the events of 2020 exacerbated preexisting health-related inequities.

Association of Common Pediatric Surgeries With New Onset Chronic Pain in Patients 0-21 Years of Age in the United States

Chronic pain (CP) is a major public health issue. While new onset CP is known to occur frequently after some pediatric surgeries, its incidence after the most common pediatric surgeries is unknown. This retrospective cohort study used insurance claims data from 2002 to 2017 for patients 0 to 21 years of age. The primary outcome was CP 90 to 365 days after each of the 20 most frequent surgeries in 5 age categories (identified using CP ICD codes). Multivariable logistic regression identified surgeries and risk factors associated with CP after surgery. A total of 424,590 surgical patients aged 0 to 21 were included, 22,361 of whom developed CP in the 90 to 365 days after surgery. The incidences of CP after surgery were: 1.1% in age group 0 to 1 years; 3.0% in 2 to 5 years; 5.6% in 6 to 11 years; 10.1% in 12 to 18 years; 9.9% in 19 to 21 years. Some surgeries and patient variables were associated with CP. Approximately 1 in 10 adolescents who underwent the most common surgeries developed CP, as did a striking percentage of children in other age groups. Given the long-term consequences of CP, resources should be allocated toward identification of high-risk pediatric patients and strategies to prevent CP after surgery. PERSPECTIVE: This study identifies the incidences of and risk factors for chronic pain after common surgeries in patients 0 to 21 years of age. Our findings suggest that resources should be allocated toward the identification of high-risk pediatric patients and strategies to prevent CP after surgery.

1002. Complex Outpatient Antimicrobial Therapy (COpAT) Program at a Rural Academic Medical Center: Evaluation of First 100 Patients

Background

Literature shows early intravenous (IV) to oral (PO) antimicrobial transition for infective endocarditis (IE) and bone and joint infection (BJI) is noninferior to prolonged IV antimicrobial therapy. COVID-19 pandemic peaks resulted in critical shortages of staffed hospital beds spurring innovation. Outpatient parenteral antimicrobial therapy (OPAT), a well-established program using prolonged IV antimicrobials, faces challenges such as infusion resource needs and social circumstance limitations. Complex outpatient antimicrobial therapy (COpAT) uses PO in place of IV antimicrobials. We hypothesized rapid adoption of COpAT would decrease hospital length of stay and open beds while retaining satisfactory clinical outcomes.

Methods

COpAT protocols (Image 1) and guidelines by infection type and isolated organism (Image 2) were created. Hospitalized patients including persons who inject drugs (PWID) were evaluated for IV to PO antimicrobial transition by an infectious diseases (ID) physician and then followed by an ID physician-pharmacist team. Demographic, ID, and clinical outcome data for the first 100 COpAT patients between December 2020 and February 2022 were obtained by retrospective chart review. Image 1.COpAT Inpatient and Outpatient Protocols

Image 2. COpAT Guidelines by Infection Type and Isolated Organism

MSSA = methicillin-susceptible Staphylococcus aureus; MRSA = methicillin-resistant Staphylococcus aureus; spp. = species; TMP/SMX = trimethoprim-sulfamethoxazole; DS = double strength; SSTI = skin and soft tissue infection; CAP = community-acquired pneumonia

Results

PWID accounted for 78% of COpAT patients. BJI followed by mixed infection (IE and BJI) was most prevalent (Image 3) with bacteremia in 53% of cases. Staphylococcus aureus was most frequently isolated (Image 4). Oral linezolid and fluoroquinolones, often in combination, were most commonly used. IV and PO antimicrobials were taken for a median 28 and 14 days, respectively. The COpAT program saved 1425 IV antimicrobial and 1363 hospital days. Assuming daily inpatient cost of $2050, cost avoided was $2,794,150. COpAT patients participated in ID follow-up and adhered to PO antimicrobials with low 30-day readmission rates (Image 5). Image 3.Infection TypeImage 4.Isolated Organism CoNS = coagulase-negative staphylococci Image 5.Clinical Outcomes

Conclusion

In a sample of 100 COpAT patients including PWID, IV to PO antimicrobial transition safely saved hospital days and mitigated critical bed shortages during pandemic peaks. A successful COpAT program requires a multidisciplinary group: close ID physician-pharmacist collaboration extending to OPAT and antimicrobial stewardship teams. With a COpAT program in place, even earlier IV to PO antimicrobial transitions should be studied.

Disclosures

All Authors: No reported disclosures.

334. Clinical Outcomes with Implementation of Accelerate Pheno Blood Culture Detection System for Gram Negative Bacteremia

Background

Bacteremia is a life-threatening illness. Delayed treatment increases patient morbidity and healthcare costs. Accelerate Pheno™ Blood Culture Detection System (AXDX) is a novel diagnostic technology for rapid detection of gram-negative bacteremia. Studies have shown accurate and faster time to speciation and sensitivity (TTSS) by AXDX compared to conventional modality. Our unique study examined the direct impact of AXDX on clinical outcomes and cost.

Methods

This retrospective study consisted of 213 patients aged 18 years and older admitted to our academic institution with gram-negative bacteremia. The pre-AXDX group had 109 patients admitted in 2019 and the post-AXDX group had 104 patients admitted in 2021. Demographics, microbes, TTSS, time to de-escalation of therapy (TTDeT), length of stay (LOS), readmissions, mortality rates, and Clostridioides difficile infection (CDI) rates were recorded.

Results

The pre-AXDX group had 51.4% females, mean age of 60.3 years, mean Charlson Comorbidity Index (CCMI) of 2.2, mean LOS of 21.2 days, and mean Pitt Bacteremia Score (PBS) of 2.4. The post-AXDX group had 52.0% females, mean age of 63.7 years, mean CCMI of 3.0, mean LOS of 15.0 days, and mean PBS of 2.7. Both groups’ top 2 sources of bacteremia were urinary and gastrointestinal and top 2 microbes were Escherichia coli and Klebsiella pneumoniae. Pre-AXDX's mean TTSS was 71.9 hours and 23.6 hours for post-AXDX. Pre-AXDX's mean TTDeT was 74.0 hours and 43.9 hours for post-AXDX. The pre-AXDX cohort had 7.4% more related readmissions, 5.5% more CDI, and 0.3% more inpatient mortality than post-AXDX group.

Conclusion

In addition to faster TTSS with AXDX as seen with previous studies, our study shows clinical advantages with AXDX use. Both groups were comparable in bacteremia sources and microbes. The post-AXDX group had higher CCMI and PBS scores, indicating they were more ill. Despite this, the pre-AXDX group had 30.05 hours longer TTDeT, 6.17 days longer mean LOS, 5.45% more CDI, 7.12% more readmissions, and 0.26% higher mortality. The pre-AXDX group also reported adverse reactions to antibiotics, while post-AXDX did not. Our data shows AXDX use improves clinical outcomes with reduced adverse effects, mortality and CDI rate and lower costs with less LOS and readmission rates.

Disclosures

All Authors: No reported disclosures.

Complications of oxidised regenerated cellulose at Caesarean section: A report of two cases

Two patients underwent surgical deliveries within four months of one another at a single maternity unit. Both patients had complications of infection-like symptoms such as offensive vaginal discharge and pyrexia, months following their caesarean sections resulting in further surgery. The incidents were thought to be secondary to woven oxidised regenerated cellulose (ORC) use. ORC must be used according to its relevant product literature which can vary between brands. Surgeons must keep abreast of changes to the haemostatic material provided to them and therefore the properties of each type, especially when faced with bleeding not suitable for suturing or electrocautery.

Choroid plexus-derived extracellular vesicles exhibit brain targeting characteristics

The brain is protected against invading organisms and other unwanted substances by tightly regulated barriers. However, these central nervous system (CNS) barriers impede the delivery of drugs into the brain via the blood circulation and are therefore considered major hurdles in the treatment of neurological disorders. Consequently, there is a high need for efficient delivery systems that are able to cross these strict barriers. While most research focuses on the blood-brain barrier (BBB), the design of drug delivery platforms that are able to cross the blood-cerebrospinal fluid (CSF) barrier, formed by a single layer of choroid plexus epithelial cells, remains a largely unexplored domain. The discovery that extracellular vesicles (EVs) make up a natural mechanism for information transfer between cells and across cell layers, has stimulated interest in their potential use as drug delivery platform. Here, we report that choroid plexus epithelial cell-derived EVs exhibit the capacity to home to the brain after peripheral administration. Moreover, these vesicles are able to functionally deliver cargo into the brain. Our findings underline the therapeutic potential of choroid plexus-derived EVs as a brain drug delivery vehicle via targeting of the blood-CSF interface.

Allelic polymorphism controls autoreactivity and vaccine elicitation of human broadly neutralizing antibodies against influenza virus

Human broadly neutralizing antibodies (bnAbs) targeting the hemagglutinin stalk of group 1 influenza A viruses (IAVs) are biased for IGHV1-69 alleles that use phenylalanine (F54) but not leucine (L54) within their CDRH2 loops. Despite this, we demonstrated that both alleles encode for human IAV bnAbs that employ structurally convergent modes of contact to the same epitope. To resolve differences in lineage expandability, we compared F54 versus L54 as substrate within humanized mice, where antibodies develop with human-like CDRH3 diversity but are restricted to single VH genes. While both alleles encoded for bnAb precursors, only F54 IGHV1-69 supported elicitation of heterosubtypic serum bnAbs following immunization with a stalk-only nanoparticle vaccine. L54 IGHV1-69 was unproductive, co-encoding for anergic B cells and autoreactive stalk antibodies that were cleared from B cell memory. Moreover, human stalk antibodies also demonstrated L54-dependent autoreactivity. Therefore, IGHV1-69 polymorphism, which is skewed ethnically, gates tolerance and vaccine expandability of influenza bnAbs.

On the adsorption and reactivity of element 114, flerovium

Flerovium (Fl, element 114) is the heaviest element chemically studied so far. To date, its interaction with gold was investigated in two gas-solid chromatography experiments, which reported two different types of interaction, however, each based on the level of a few registered atoms only. Whereas noble-gas-like properties were suggested from the first experiment, the second one pointed at a volatile-metal-like character. Here, we present further experimental data on adsorption studies of Fl on silicon oxide and gold surfaces, accounting for the inhomogeneous nature of the surface, as it was used in the experiment and analyzed as part of the reported studies. We confirm that Fl is highly volatile and the least reactive member of group 14. Our experimental observations suggest that Fl exhibits lower reactivity towards Au than the volatile metal Hg, but higher reactivity than the noble gas Rn.

Control Yourself: Broad Implications of Narrowed Attention

Attention represents a key element of self-control, and multiple theoretical accounts have highlighted the role played by abundant attentional capacity in effecting successful self-regulation. What, then, are the consequences of living in today's world, in which attention can become so easily divided by a multitude of stimuli? In this article, we consider the implications of divided attention for self-control and show that although the end result is typically disinhibited behavior, under specified conditions, attentional limitation, or what we term attentional myopia, can be associated with enhanced restraint.

Immunogenicity of a germline-targeting nanoparticle in knock-in mice expressing human B cell receptors of the HIV gp41 neutralizing antibody, DH511

The Membrane Proximal External Region (MPER) of HIV Envelope represents a key target for vaccine development due to high neutralization breadth and potency of MPER-specific broadly neutralizing antibodies (bnAbs). However, neutralizing antibody responses to MPER epitopes are restricted by tolerance control and the MPER epitope is absent from many HIV immunogens under clinical investigation. Using computational design and yeast display, a candidate germline-targeting (GT5) immunogen was developed that bound strongly to the inferred human unmutated common ancestor (UCA) of the distal MPER bnAb DH511, as well as to several human DH511-like potential precursor antibodies. We studied the immunogenicity of a multimeric nanoparticle of the GT5 immunogen in a knock-in mouse line expressing human DH511.UCA B cell receptors (BCRs). Naïve DH511.UCA knock-in mice exhibited a reduction in overall B cell numbers, and DH511.UCA-bearing B cells expressed low levels of surface IgM and IgD, suggesting that DH511.UCA expression is subject to immune tolerance control. Nonetheless, following immunization with GT5 nanoparticles mixed with a saponin/monophosphoryl lipid A adjuvant, knock-in mice mounted robust anti-GT5 humoral responses, including anti-GT5 IgG in serum and GT5-specific germinal center B cells and T follicular helper cells in lymphoid tissues. Sequencing analysis of IgG+ GT5-specific B cells revealed improbable mutations in knock-in immunoglobulin genes of DH511.UCA. These studies will guide further optimization of immunogens with potential to select for development of bnAbs against MPER epitopes.

Supported by a grant from NIH (P01-AI138211) 

B cell convergence to distinct broadly reactive epitopes revealed by chimeric hemagglutinin vaccination

Seasonal influenza virus vaccines provide modest protection against endemic viruses but lack effectiveness against pandemic-threat viruses. Therefore, new immunogens and vaccine platforms that induce antibodies against broadly protective epitopes are needed to provide robust protection against seasonal and novel influenza viruses. In a phase 1 clinical trial, the chimeric hemagglutinin (cHA) immunogen induced antibody responses against the conserved HA stalk domain. However, the landscape of the B cell specificities and subsets induced by this vaccine remain undetermined. Using single cell RNA-sequencing and repertoire sequencing, we identified that formulation of the cHA vaccine differentially induced B cell responses against distinct epitopes. Notably, those participants that received an inactivated vaccine with a squalene-based adjuvant had a greater proportion of B cells targeting two conserved neutralizing epitopes of the stalk domain: the central stalk and anchor epitopes. Moreover, participants that received an inactivated vaccine with adjuvant had distinct transcriptional B cell subsets, including an increase in atypical memory B cells. B cell clonal overlap between acute and memory timepoints was substantial, with several multi-donor clones that targeted distinct broadly protective epitopes. In addition, we identified stalk targeting germline antibodies that could neutralize recent pandemic H1N1 viruses. Altogether, our study reveals that the inactivated cHA vaccine with an oil-in-water adjuvant promotes B cell activation and maturation against broadly protective epitopes.

Supported by National Institute of Allergy and Infectious Diseases (NIAID) National Institutes of Health grant numbers K99AI159136 (JJG), U19AI082724 (PCW), U19AI109946 (PCW), U19AI057266 (PCW), P01AI097092 (PP), R01AI145870-01 (PP), R21AI146529 (LC), and T32AI007244-36 (JH), the NIAID Centers of Excellence for Influenza Research and Surveillance (CEIRS) grant number HHSN272201400005C (PCW),  HHSN272201400008C (LC, FK, PP), and the NIAD Centers of Excellence for Influenza Research and Response (CEIRR) grant number 75N93019R00028 (PCW, FK, PP). This work was also partially supported by the NIAID Collaborative Influenza Vaccine Innovation Centers (CIVIC; 75N93019C00051, FK, PP, ABW, PCW).

COVID-19 is associated with higher risk of venous thrombosis, but not arterial thrombosis, compared with influenza: Insights from a large US cohort

Introduction

Infection with SARS-CoV-2 is typically compared with influenza to contextualize its health risks. SARS-CoV-2 has been linked with coagulation disturbances including arterial thrombosis, leading to considerable interest in antithrombotic therapy for Coronavirus Disease 2019 (COVID-19). However, the independent thromboembolic risk of SARS-CoV-2 infection compared with influenza remains incompletely understood. We evaluated the adjusted risks of thromboembolic events after a diagnosis of COVID-19 compared with influenza in a large retrospective cohort.

Methods

We used a US-based electronic health record (EHR) dataset linked with insurance claims to identify adults diagnosed with COVID-19 between April 1, 2020 and October 31, 2020. We identified influenza patients diagnosed between October 1, 2018 and April 31, 2019. Primary outcomes [venous composite of pulmonary embolism (PE) and acute deep vein thrombosis (DVT); arterial composite of ischemic stroke and myocardial infarction (MI)] and secondary outcomes were assessed 90 days post-diagnosis. Propensity scores (PS) were calculated using demographic, clinical, and medication variables. PS-adjusted hazard ratios (HRs) were calculated using Cox proportional hazards regression.

Results

There were 417,975 COVID-19 patients (median age 57y, 61% women), and 345,934 influenza patients (median age 47y, 66% women). Compared with influenza, patients with COVID-19 had higher venous thromboembolic risk (HR 1.53, 95% CI 1.38–1.70), but not arterial thromboembolic risk (HR 1.02, 95% CI 0.95–1.10). Secondary analyses demonstrated similar risk for ischemic stroke (HR 1.11, 95% CI 0.98–1.25) and MI (HR 0.93, 95% CI 0.85–1.03) and higher risk for DVT (HR 1.36, 95% CI 1.19–1.56) and PE (HR 1.82, 95% CI 1.57–2.10) in patients with COVID-19.

Conclusion

In a large retrospective US cohort, COVID-19 was independently associated with higher 90-day risk for venous thrombosis, but not arterial thrombosis, as compared with influenza. These findings may inform crucial knowledge gaps regarding the specific thromboembolic risks of COVID-19.

Disparities in quality of life, social distress and employment outcomes in Australian cancer survivors

PURPOSE

To examine how socio-demographic, comorbidities and information needs influence quality of life (QoL) outcomes of survivors of breast, colorectal, or prostate cancer, non-Hodgkin lymphoma or melanoma.

METHODS

Cross-sectional postal survey with eligible participants identified through a population-based cancer registry. QoL outcomes were assessed by EQ-5D-5L, social difficulties index (SDI) and, for those employed at diagnosis, current employment. Regression analyses explored associations between outcome variables and cancer type, age, time since diagnosis, residential location, socio-economic disadvantage, comorbidities and unmet information needs. Mediation analyses examined whether comorbidities and information needs explained relationships between outcome variables and socio-economic disadvantage.

RESULTS

2115 survivors participated. Mean EQ-5D-5L scores (mean = 0.84) were similar to population averages and SDI scores were low for the entire sample (mean = 3.80). In multivariate analyses, being aged over 80, greater socio-economic disadvantage, comorbidities and unmet information needs decreased EQ-5D-5L scores. Higher SDI scores were associated with socio-economic disadvantage, comorbidities and unmet information needs. Not being employed was associated with being aged over 50, more comorbidities and socio-economic disadvantage. Comorbidities but not information needs partially mediated the impact of socio-economic disadvantage on EQ-5D-5L and SDI accounting for 17% and 14% of the total effect of socio-economic disadvantage respectively. Neither comorbidities nor information needs mediated the association between socio-economic disadvantage and employment outcomes.

CONCLUSIONS

To improve quality of life, survivorship care should be better tailored to address the needs of individuals given their overall health and impact of comorbidities, their age and type of cancer and not simply time since diagnosis.

Single-molecule mechanical fingerprinting with DNA nanoswitch calipers

Decoding the identity of biomolecules from trace samples is a longstanding goal in the field of biotechnology. Advances in DNA analysis have substantially affected clinical practice and basic research, but corresponding developments for proteins face challenges due to their relative complexity and our inability to amplify them. Despite progress in methods such as mass spectrometry and mass cytometry, single-molecule protein identification remains a highly challenging objective. Towards this end, we combine DNA nanotechnology with single-molecule force spectroscopy to create a mechanically reconfigurable DNA nanoswitch caliper capable of measuring multiple coordinates on single biomolecules with atomic resolution. Using optical tweezers, we demonstrate absolute distance measurements with ångström-level precision for both DNA and peptides, and using multiplexed magnetic tweezers, we demonstrate quantification of relative abundance in mixed samples. Measuring distances between DNA-labelled residues, we perform single-molecule fingerprinting of synthetic and natural peptides, and show discrimination, within a heterogeneous population, between different posttranslational modifications. DNA nanoswitch calipers are a powerful and accessible tool for characterizing distances within nanoscale complexes that will enable new applications in fields such as single-molecule proteomics.

First Study on Nihonium (Nh, Element 113) Chemistry at TASCA

Nihonium (Nh, element 113) and flerovium (Fl, element 114) are the first superheavy elements in which the 7p shell is occupied. High volatility and inertness were predicted for Fl due to the strong relativistic stabilization of the closed 7p 1/2 sub-shell, which originates from a large spin-orbit splitting between the 7p 1/2 and 7p 3/2 orbitals. One unpaired electron in the outermost 7p 1/2 sub-shell in Nh is expected to give rise to a higher chemical reactivity. Theoretical predictions of Nh reactivity are discussed, along with results of the first experimental attempts to study Nh chemistry in the gas phase. The experimental observations verify a higher chemical reactivity of Nh atoms compared to its neighbor Fl and call for the development of advanced setups. First tests of a newly developed detection device miniCOMPACT with highly reactive Fr isotopes assure that effective chemical studies of Nh are within reach.

Machine learning approaches improve risk stratification for secondary cardiovascular disease prevention in multiethnic patients

Objectives

Identifying high-risk patients is crucial for effective cardiovascular disease (CVD) prevention. It is not known whether electronic health record (EHR)-based machine-learning (ML) models can improve CVD risk stratification compared with a secondary prevention risk score developed from randomised clinical trials (Thrombolysis in Myocardial Infarction Risk Score for Secondary Prevention, TRS 2°P).

Methods

We identified patients with CVD in a large health system, including atherosclerotic CVD (ASCVD), split into 80% training and 20% test sets. A rich set of EHR patient features was extracted. ML models were trained to estimate 5-year CVD event risk (random forests (RF), gradient-boosted machines (GBM), extreme gradient-boosted models (XGBoost), logistic regression with an L₂ penalty and L₁ penalty (Lasso)). ML models and TRS 2°P were evaluated by the area under the receiver operating characteristic curve (AUC).

Results

The cohort included 32 192 patients (median age 74 years, with 46% female, 63% non-Hispanic white and 12% Asian patients and 23 475 patients with ASCVD). There were 4010 events over 5 years of follow-up. ML models demonstrated good overall performance; XGBoost demonstrated AUC 0.70 (95% CI 0.68 to 0.71) in the full CVD cohort and AUC 0.71 (95% CI 0.69 to 0.73) in patients with ASCVD, with comparable performance by GBM, RF and Lasso. TRS 2°P performed poorly in all CVD (AUC 0.51, 95% CI 0.50 to 0.53) and ASCVD (AUC 0.50, 95% CI 0.48 to 0.52) patients. ML identified nontraditional predictive variables including education level and primary care visits.

Conclusions

In a multiethnic real-world population, EHR-based ML approaches significantly improved CVD risk stratification for secondary prevention.

COVID-19 is associated with higher risk of venous thrombosis, but not arterial thrombosis, compared with influenza: Insights from a large US cohort

Introduction

Infection with SARS-CoV-2 is typically compared with influenza to contextualize its health risks. SARS-CoV-2 has been linked with coagulation disturbances including arterial thrombosis, leading to considerable interest in antithrombotic therapy for Coronavirus Disease 2019 (COVID-19). However, the independent thromboembolic risk of SARS-CoV-2 infection compared with influenza remains incompletely understood. We evaluated the adjusted risks of thromboembolic events after a diagnosis of COVID-19 compared with influenza in a large retrospective cohort.

Methods

We used a US-based electronic health record (EHR) dataset linked with insurance claims to identify adults diagnosed with COVID-19 between April 1, 2020 and October 31, 2020. We identified influenza patients diagnosed between October 1, 2018 and April 31, 2019. Primary outcomes [venous composite of pulmonary embolism (PE) and acute deep vein thrombosis (DVT); arterial composite of ischemic stroke and myocardial infarction (MI)] and secondary outcomes were assessed 90 days post-diagnosis. Propensity scores (PS) were calculated using demographic, clinical, and medication variables. PS-adjusted hazard ratios (HRs) were calculated using Cox proportional hazards regression.

Results

There were 417,975 COVID-19 patients (median age 57y, 61% women), and 345,934 influenza patients (median age 47y, 66% women). Compared with influenza, patients with COVID-19 had higher venous thromboembolic risk (HR 1.53, 95% CI 1.38–1.70), but not arterial thromboembolic risk (HR 1.02, 95% CI 0.95–1.10). Secondary analyses demonstrated similar risk for ischemic stroke (HR 1.11, 95% CI 0.98–1.25) and MI (HR 0.93, 95% CI 0.85–1.03) and higher risk for DVT (HR 1.36, 95% CI 1.19–1.56) and PE (HR 1.82, 95% CI 1.57–2.10) in patients with COVID-19.

Conclusion

In a large retrospective US cohort, COVID-19 was independently associated with higher 90-day risk for venous thrombosis, but not arterial thrombosis, as compared with influenza. These findings may inform crucial knowledge gaps regarding the specific thromboembolic risks of COVID-19.

1065 Exposing the Incidence of Ileus in Pelvic and Acetabular Fractures: A Retrospective Case Analysis

Background

Paralytic ileus is a temporary inhibition of gastrointestinal mobility in the absence of mechanical obstruction. Ileus has previously been observed in up to 40% of patients undergoing bowel surgery, leading to increased morbidity and length of stay. Pelvic and acetabular fractures are often caused by high energy trauma and are associated with a risk of visceral injury. This is the first study to report the incidence of and risk factors for ileus following admission with pelvic and/or acetabular fractures.

Method

All patients over the age of 16 presenting to a major trauma centre throughout 2019 were included. Data included patient demographics, injury pattern, fracture management and presence of ileus. Previous studies identified patients as having ileus if they failed to tolerate an oral diet and open their bowels for more than three days (GI-2). Analysis assessed risk factors for ileus as well as its effect on length of stay.

Results

An incidence of ileus of 40.35% was observed in the 57 included patients. Ileus was three times more common in patients with a diagnosis of diabetes mellitus (p = 0.56) and 2.5 times more common in the presence of an open pelvic/acetabular fracture (p = 0.73). Length of stay was significantly longer in patients under 65 years identified as having ileus (p = 0.046). Gender, age, opiate use, fracture management and surgical approach were not identified as risk factors.

Conclusions

The authors have identified the essentiality of early risk factor identification and hope to encourage further research to create a prognostic tool.

965 Complication Rates in Operatively Managed Ankle Fracture/Dislocations - The Effect of Pre-Reduction Imaging and Compliance with BOAST 12 Guidance

Aim

The BOAST-12 guidelines for the management of ankle fractures aims to optimise functional recovery and reduce complications. They advise against having radiographs prior to urgent reduction of clinically deformed ankles as it could cause an unacceptable delay to subsequent management. Our study aimed to assess the effect of time to acceptable reduction on the risk of complications and time to definitive reduction.

Method

This was a retrospective observational study of patients with ankle fracture-dislocations between 2013 to 2017 at the Northern General Hospital’s Emergency Department (ED). Information collected from 2 patient groups (with and without pre-reduction radiographs), included patient demographics, time to accepted reduction, number of manipulations, operations, and subsequent complications.

Results

242 patients were identified. Time from arrival in ED to acceptable reduction was significantly longer in patients with pre-reduction radiographs versus patients without (184.5 vs 82 minutes, p &lt; 0.00), but did not increase the overall risk of complications (p = 0.62). Pre-reduction radiographs were associated with insignificantly higher rates of post-traumatic osteoarthritis (p = 0.17) and slightly longer wait time for definitive intervention (1 vs 2 days, p = 0.72). However, this had no relationship with the number of manipulations (p = 0.53).

Conclusions

The use of pre-reduction radiographs significantly increased time to acceptable reduction of ankle fracture-dislocations. However, this was not associated with increased risk of complications or time to definitive management.

Integrating 31-Gene Expression Profiling With Clinicopathologic Features to Optimize Cutaneous Melanoma Sentinel Lymph Node Metastasis Prediction

National guidelines recommend sentinel lymph node biopsy (SLNB) be offered to patients with > 10% likelihood of sentinel lymph node (SLN) positivity. On the other hand, guidelines do not recommend SLNB for patients with T1a tumors without high-risk features who have < 5% likelihood of a positive SLN. However, the decision to perform SLNB is less certain for patients with higher-risk T1 melanomas in which a positive node is expected 5%-10% of the time. We hypothesized that integrating clinicopathologic features with the 31-gene expression profile (31-GEP) score using advanced artificial intelligence techniques would provide more precise SLN risk prediction.

Physical attractiveness predicts endorsement of specific evolutionary psychology principles

Evolutionary psychology has emerged as a controversial discipline, particularly with regard to its claims concerning the biological basis of sex differences in human mate preferences. Drawing on theories of motivated inference, we hypothesized that those who are most likely to be privileged by specific aspects of the theory would be most likely to support the theory. In particular, we predicted that physical attractiveness would be positively associated with endorsement of predictions of evolutionary psychology concerning mating strategies. Two studies confirmed this hypothesis. In Study 1, participants rated as higher in physical attractiveness were more likely to support specific principles of evolutionary psychology. In Study 2, a manipulation designed to boost self-perceived physical attractiveness increased endorsement of those same principles. Observer-rated physical attractiveness generally predicted individuals’ support of the theoretical principles better than did gender, political orientation, or self-esteem. Results suggest that those most likely to benefit according to certain predictions of evolutionary psychology are also those most likely to be sympathetic toward its relevant principles.

Improved individual and population-level HbA1c estimation using CGM data and patient characteristics

Machine learning and linear regression models using CGM and participant data reduced HbA1c estimation error by up to 26% compared to the GMI formula, and exhibit superior performance in estimating the median of HbA1c at the cohort level, potentially of value for remote clinical trials interrupted by COVID-19.

Imprinted Gene Expression and Function of the Dopa Decarboxylase Gene in the Developing Heart

Dopa decarboxylase (DDC) synthesizes serotonin in the developing mouse heart where it is encoded by Ddc_exon1a, a tissue-specific paternally expressed imprinted gene. Ddc_exon1a shares an imprinting control region (ICR) with the imprinted, maternally expressed (outside of the central nervous system) Grb10 gene on mouse chromosome 11, but little else is known about the tissue-specific imprinted expression of Ddc_exon1a. Fluorescent immunostaining localizes DDC to the developing myocardium in the pre-natal mouse heart, in a region susceptible to abnormal development and implicated in congenital heart defects in human. Ddc_exon1a and Grb10 are not co-expressed in heart nor in brain where Grb10 is also paternally expressed, despite sharing an ICR, indicating they are mechanistically linked by their shared ICR but not by Grb10 gene expression. Evidence from a Ddc_exon1a gene knockout mouse model suggests that it mediates the growth of the developing myocardium and a thinning of the myocardium is observed in a small number of mutant mice examined, with changes in gene expression detected by microarray analysis. Comparative studies in the human developing heart reveal a paternal expression bias with polymorphic imprinting patterns between individual human hearts at DDC_EXON1a, a finding consistent with other imprinted genes in human.

1005 Antibiotic-Impregnated Calcium Sulfate Beads Are Not Effective in the Primary Prevention of Infection in Open Femur and Tibia Fractures

Introduction

Infection is a major complication of open fractures. Antibiotic-impregnated calcium sulfate (AICS) beads are widely used as an adjuvant to systemic antibiotics. Whilst their efficacy in the secondary prevention of infection is established, we present the first retrospective study evaluating AICS beads in the primary prevention of infection in open fractures.

Method

214 open femur and tibia fractures in 207 patients were reviewed over a seven-year period. 148 fractures received only systemic antibiotic prophylaxis. 66 fractures also received AICS beads. The occurrence of acute infection (wound infection and acute osteomyelitis) was recorded, as well as that of long-term complications (chronic osteomyelitis, non-union and death).

Results

Fractures that received AICS with systemic antibiotics had an overall acute infection rate of 42% (28/66), compared to 43% (63/148) in fractures that received only systemic antibiotics (p &gt; 0.05). There was no significant difference in infection rate even when fractures were stratified by Gustilo-Anderson grade. There was also no significant difference in the rate of long-term complications.

Conclusions

Our results indicate that the adjuvant use of AICS beads is not effective for the primary prevention of acute infection or long-term complications in open leg fractures. Further research is needed to elucidate the factors influencing the outcomes of AICS use.

Prediction of Prolonged Opioid Use After Surgery in Adolescents: Insights From Machine Learning

BACKGROUND

Long-term opioid use has negative health care consequences. Patients who undergo surgery are at risk for prolonged opioid use after surgery (POUS). While risk factors have been previously identified, no methods currently exist to determine higher-risk patients. We assessed the ability of a variety of machine-learning algorithms to predict adolescents at risk of POUS and to identify factors associated with this risk.

METHODS

A retrospective cohort study was conducted using a national insurance claims database of adolescents aged 12-21 years who underwent 1 of 1297 surgeries, with general anesthesia, from January 1, 2011 to December 30, 2017. Logistic regression with an L2 penalty and with a logistic regression with an L1 lasso (Lasso) penalty, random forests, gradient boosting machines, and extreme gradient boosted models were trained using patient and provider characteristics to predict POUS (≥1 opioid prescription fill within 90-180 days after surgery) risk. Predictive capabilities were assessed using the area under the receiver-operating characteristic curve (AUC)/C-statistic, mean average precision (MAP); individual decision thresholds were compared using sensitivity, specificity, Youden Index, F1 score, and number needed to evaluate. The variables most strongly associated with POUS risk were identified using permutation importance.

RESULTS

Of 186,493 eligible patient surgical visits, 8410 (4.51%) had POUS. The top-performing algorithm achieved an overall AUC of 0.711 (95% confidence interval [CI], 0.699-0.723) and significantly higher AUCs for certain surgeries (eg, 0.823 for spinal fusion surgery and 0.812 for dental surgery). The variables with the strongest association with POUS were the days' supply of opioids and oral morphine milligram equivalents of opioids in the year before surgery.

CONCLUSIONS

Machine-learning models to predict POUS risk among adolescents show modest to strong results for different surgeries and reveal variables associated with higher risk. These results may inform health care system-specific identification of patients at higher risk for POUS and drive development of preventative measures.

Eating up cognitive resources: Does attentional consumption lead to food consumption?

What is the role played by attentional load in eating? Does attending to an unrelated task generally lead to overeating, perhaps by preventing individuals from focusing on a goal to limit consumption? Or does such attentional diversion typically lead to reductions in eating, perhaps by preventing people from noticing tempting features of relevant food cues? Past research has supported each of these two propositions, but comparisons between existing studies have been hampered to the extent that various experimental manipulations differ in the degree to which they occupy attention, as well as differing in the particular type of attentional resources they exploit. To resolve existing discrepancies in the literature, in a series of studies, we made use of a working memory manipulation, the n-back task (Kirchner, 1958), that can be systematically modified to induce varying levels of cognitive load, allowing for rigorous comparisons of the effects of different levels of attentional load on eating. These studies revealed a complex pattern of results. Analysis of findings from three studies employing within-subjects designs documented a linear relationship, in that participants consumed less food when completing a higher cognitive-load task than when completing a lower cognitive-load task. Three studies employing between-subjects designs highlighted a less consistent pattern of results, but when combined in a mini-meta-analysis, suggested the opposite linear relationship, with participants assigned to higher cognitive-load conditions generally consuming more food than participants assigned to lower cognitive-load conditions. We conducted two additional studies to reconcile these conflicting patterns of data. Neither finding received unequivocal support, although both studies found that participants ate less when engaged in higher cognitive-load tasks than lower cognitive-load tasks. The precise nature of the relationship between attentional load and eating remains elusive.

Single-molecule force spectroscopy reveals the dynamic strength of the hair-cell tip-link connection

The conversion of auditory and vestibular stimuli into electrical signals is initiated by force transmitted to a mechanotransduction channel through the tip link, a double stranded protein filament held together by two adhesion bonds in the middle. Although thought to form a relatively static structure, the dynamics of the tip-link connection has not been measured. Here, we biophysically characterize the strength of the tip-link connection at single-molecule resolution. We show that a single tip-link bond is more mechanically stable relative to classic cadherins, and our data indicate that the double stranded tip-link connection is stabilized by single strand rebinding facilitated by strong cis-dimerization domains. The measured lifetime of seconds suggests the tip-link is far more dynamic than previously thought. We also show how Ca2+ alters tip-link lifetime through elastic modulation and reveal the mechanical phenotype of a hereditary deafness mutation. Together, these data show how the tip link is likely to function during mechanical stimuli.