Nocebo belief and attitudes towards side effect disclosure: A general population-based online survey in Europe and North America.

BACKGROUND: With evidence for large nocebo effects in pain, guidelines for nocebo-minimizing strategies regarding side effect disclosure are emerging. While the ethical implications and effectiveness of such strategies have been the subject of investigations, the perspective of healthcare users are missing despite the stakes for patient autonomy. METHODS: In an online survey, 2766 adults (≥18 years) from a general population sample in Europe and North America responded to questions related to nocebo familiarity, nocebo beliefs and attitudes towards side effect disclosure. RESULTS: Only 474 (17%) were familiar with nocebo terminology, while 1379 (50%) were familiar with the concept of nocebo side effects. Belief in nocebo side effects was not well-established; 738 (31%) agreed that side effect information could increase side effect occurrence. Nocebo belief was associated with more negative attitudes towards side effect disclosure and 1962 (73%) indicated that positive framing was an acceptable way of disclosing side effect information. In general, the majority of participants (65-76%) held positive attitudes towards the disclosure of all potential side effects and 2309 (84%) favoured patient autonomy over nonmaleficence. Although the general patterns were similar in the European and North American sample, the latter showed stronger nocebo belief and stronger positive attitudes towards side effect disclosure. CONCLUSIONS: The study found a consistent, moderate association between nocebo belief and attitudes towards nondisclosure, alongside positive attitudes towards the use of framing. Together with the discovered discrepancy between nocebo familiarity and nocebo belief, these findings have implications for the implementation of nocebo education and risk framing strategies. SIGNIFICANCE STATEMENT: This is the first large-scale, general population-based study to contribute to the scientific discussion about nocebo side effects from the perspective of healthcare users. The findings have implications for the discussion on how to handle the medical and ethical problem of nocebo side effects in clinical practice.

Nurse prescribing and dispensing in South Africa: Gaps in the current legislative framework.

Background: Nurse prescribing and dispensing are central to ensuring universal health access in South Africa. Objective: To describe the historical development of the legal enablements of nurse prescribing and dispensing in South Africa and highlight gaps in the current legislative framework. Method: This is a discussion article. Results: We emphasise significant deficiencies in the current legislative landscape that pose challenges to these vital nursing practices and call for urgent revisions of the legislative framework, particularly the revision of Section 56 of the Nursing Act (33 of 2005) and its related regulations, to formalise authorisation of specialist nurse prescribers in public and private practice. This will also entail an application to the South African Health Products Regulatory Authority (SAPHRA) for the scheduling of substances by authorised nurse prescribers in the defined professional nurse and specialist nurse categories by the Minister of Health. Conclusion: There is a necessity for prompt legislative revisions to address identified deficiencies. Contribution: The contribution of this article lies in its advocacy for changes to the regulatory framework to further enable nurses to deliver safe and comprehensive health care.

Implications of subclinical tuberculosis for vaccine trial design and global effect.

Tuberculosis is a leading cause of death from an infectious agent globally. Infectious subclinical tuberculosis accounts for almost half of all tuberculosis cases in national tuberculosis prevalence surveys, and possibly contributes to transmission and might be associated with morbidity. Modelling studies suggest that new tuberculosis vaccines could have substantial health and economic effects, partly based on the assumptions made regarding subclinical tuberculosis. Evaluating the efficacy of prevention of disease tuberculosis vaccines intended for preventing both clinical and subclinical tuberculosis is a priority. Incorporation of subclinical tuberculosis as a composite endpoint in tuberculosis vaccine trials can help to reduce the sample size and duration of follow-up and to evaluate the efficacy of tuberculosis vaccines in preventing clinical and subclinical tuberculosis. Several design options with various benefits, limitations, and ethical considerations are possible in this regard, which would allow for the generation of the evidence needed to estimate the positive global effects of tuberculosis vaccine trials, in addition to informing policy and vaccination strategies.

The effectiveness of selection in a species affects the direction of amino acid frequency evolution.

Nearly neutral theory predicts that species with higher effective population size (N e ) are better able to purge slightly deleterious mutations. We compare evolution in high-N e vs. low-N e vertebrates to reveal which amino acid frequencies are subject to subtle selective preferences. We take three complementary approaches, two measuring flux and one measuring outcomes. First, we fit non-stationary substitution models of amino acid flux using maximum likelihood, comparing the high-N e clade of rodents and lagomorphs to its low-N e sister clade of primates and colugos. Second, we compare evolutionary outcomes across a wider range of vertebrates, via correlations between amino acid frequencies and N e . Third, we dissect the details of flux in human, chimpanzee, mouse, and rat, as scored by parsimony - this also enables comparison to a historical paper. All three methods agree on which amino acids are preferred under more effective selection. Preferred amino acids tend to be smaller, less costly to synthesize, and to promote intrinsic structural disorder. Parsimony-induced bias in the historical study produces an apparent reduction in structural disorder, perhaps driven by slightly deleterious substitutions. Within highly exchangeable pairs of amino acids, arginine is strongly preferred over lysine, and valine over isoleucine, consistent with more effective selection preferring a marginally larger free energy of folding. These two preferences match differences between thermophiles and mesophilic relatives. These results reveal the biophysical consequences of mutation-selection-drift balance, and demonstrate the utility of nearly neutral theory for understanding protein evolution.

Assessing the longevity of attribute framing in attenuating the nocebo effect to brand and generic medication.

The perception of taking a generic, relative to brand, medication has been demonstrated to exacerbate the nocebo effect. Conversely, positive attribute framing has been shown to attenuate the nocebo effect. However, little is known about the longevity of positive attribute framing nor how it interacts with generic versus brand treatment cues. Healthy participants (N = 205) were randomised to receive either sham-modafinil capsules with a brand or generic appearance, in conjunction with standard negative side effect framing (brand-negative: N = 42; generic-negative: N = 41) or positive side effect framing (brand-positive: N = 40; generic-positive: N = 40). The remainder were randomised to a no-treatment control (N = 42). Participants were informed that modafinil could enhance alertness and cognitive performance and reduce fatigue. Critically, modafinil was described as having several potential side effects. Treatment-related side effects, alertness, fatigue and cognitive performance were measured at baseline, 30-min post-treatment and 24 h later. Nocebo and placebo effects were observed across modafinil-treated participants relative to control. Positive framing significantly reduced warned side effects for 24 h. Perceived side effect likelihood, severity, and worry mediated the nocebo, but not framing, effect. Results have important implications for the presentation of side effect information, providing a potential route to reduce unwanted negative effects of generic medication.

Innovations in the Treatment of Spinal Cerebrospinal Fluid Leaks.

Spontaneous spinal cerebrospinal fluid (CSF) leaks are uncommon but can be neurologically debilitating. When initial treatments fail, definitive repair or closure of the leak is indicated. Depending upon the type of leak present, innovative strategies for their treatment have been developed. Among them are open surgical techniques using a transdural approach for the closure of ventral CSF leaks, minimally invasive tubular techniques for the reduction and repair of lateral meningeal diverticula, and endovascular embolization of CSF-venous fistulas. Illustrative cases demonstrating the indications for and implementation of these techniques are provided.

Seracam: characterisation of a new small field of view hybrid gamma camera for nuclear medicine.

BACKGROUND: Portable gamma cameras are being developed for nuclear medicine procedures such as thyroid scintigraphy. This article introduces Seracam® - a new technology that combines small field of view gamma imaging with optical imaging - and reports its performance and suitability for small organ imaging. METHODS: The count rate capability, uniformity, spatial resolution, and sensitivity for 99mTc are reported for four integrated pinhole collimators of nominal sizes of 1 mm, 2 mm, 3 mm and 5 mm. Characterisation methodology is based on NEMA guidelines, with some adjustments necessitated by camera design. Two diagnostic scenarios - thyroid scintigraphy and gastric emptying - are simulated using clinically relevant activities and geometries to investigate application-specific performance. A qualitative assessment of the potential benefits and disadvantages of Seracam is also provided. RESULTS: Seracam's performance across the measured characteristics is appropriate for small field of view applications in nuclear medicine. At an imaging distance of 50 mm, corresponding to a field of view of 77.6 mm × 77.6 mm, spatial resolution ranged from 4.6 mm to 26 mm and sensitivity from 3.6 cps/MBq to 52.2 cps/MBq, depending on the collimator chosen. Results from the clinical simulations were particularly promising despite the challenging scenarios investigated. The optimal collimator choice was strongly application dependent, with gastric emptying relying on the higher sensitivity of the 5 mm pinhole whereas thyroid imaging benefitted from the enhanced spatial resolution of the 1 mm pinhole. Signal to noise ratio in images was improved by pixel binning. Seracam has lower measured sensitivity when compared to a traditional large field of view gamma camera, for the simulated applications this is balanced by advantages such as high spatial resolution, portability, ease of use and real time gamma-optical image fusion and display. CONCLUSION: The results show that Seracam has appropriate performance for small organ 99mTc imaging. The results also show that the performance of small field of view systems must be considered holistically and in clinically appropriate scenarios.

Measuring Community Urbanicity and Its Influence on Household Food Security Across Nepal's Agroecological Zones.

Background: Urbanization influences food systems and food security, but research on these associations in low- and middle-income countries remain limited, partly because of the binary and unstandardized "urban compared with rural" classifications. Objectives: To develop a community urbanicity scale, to assess its associations with household food security, and to explore whether agricultural occupation modifies this relationship across the 3 agroecological zones (mountain, hill, Tarai) of Nepal. Methods: Data came from a nationally and agroecologically representative, multistaged 2013 agri-food system survey of 4285 households with children <5 y in 63 communities (wards) in Nepal. A novel community-level urbanicity scale was constructed using factor analysis that included 8 domains. Multilevel mixed effects logistic regression was used to assess associations between urbanicity and household food security (measured using the validated Household Food Insecurity Access Scale), and to investigate modifying effects of agricultural occupation. Results: Urbanicity scores ranged between 13 and 69, of a possible 80 points. Most agricultural households in the mountains (67%) and hills (54%) were categorized food insecure. Increases in urbanicity were negatively associated with food insecurity, controlling for other factors (odds ratio [OR] per 10-unit urbanicity difference OR: 0.82; confidence interval [CI]: 0.71, 0.94; P ≤ 0.05). Agricultural occupation may have positively influenced this association though was not a statistically significant effect measure modifier (P = 0.07). Conclusions: The novel scale shows more nuance within Nepal's agroecological zones, which had similar urbanicity-to-food security relationships as well as overlapping urbanicity score distributions. Research and policy efforts should consider using scales providing more precise urbanicity measurement, and thus informative assessments on its role in predicting food insecurity, especially in agriculturally reliant populations.

Multiomic analysis identifies a high-risk signature that predicts early clinical failure in DLBCL.

Recent genetic and molecular classification of DLBCL has advanced our knowledge of disease biology, yet were not designed to predict early events and guide anticipatory selection of novel therapies. To address this unmet need, we used an integrative multiomic approach to identify a signature at diagnosis that will identify DLBCL at high risk of early clinical failure. Tumor biopsies from 444 newly diagnosed DLBCL were analyzed by WES and RNAseq. A combination of weighted gene correlation network analysis and differential gene expression analysis was used to identify a signature associated with high risk of early clinical failure independent of IPI and COO. Further analysis revealed the signature was associated with metabolic reprogramming and identified cases with a depleted immune microenvironment. Finally, WES data was integrated into the signature and we found that inclusion of ARID1A mutations resulted in identification of 45% of cases with an early clinical failure which was validated in external DLBCL cohorts. This novel and integrative approach is the first to identify a signature at diagnosis, in a real-world cohort of DLBCL, that identifies patients at high risk for early clinical failure and may have significant implications for design of therapeutic options.

Superficial Neurocristic EWSR1::FLI1 Fusion Tumor: A Distinctive, Clinically Indolent, S100 Protein/SOX10-Positive Neoplasm.

It is now understood that identical gene fusions may be shared by different entities. We report a distinctive neoplasm of the skin and subcutis, harboring the Ewing sarcoma-associated EWSR1::FLI1 fusion but differing otherwise from Ewing sarcoma. Slides and blocks for 5 cutaneous neoplasms coded as other than Ewing sarcoma and harboring EWSR1::FLI1 were retrieved. Immunohistochemical and molecular genetic results were abstracted from reports. Methylation profiling was performed. Clinical information was obtained. The tumors occurred in 4 men and 1 woman (median: 25 years of age; range: 19-69 years) and involved the skin/subcutis of the back (2), thigh, buttock, and chest wall (median: 2.4 cm; range: 1-11 cm). Two tumors were present "years" before coming to clinical attention. The lesions were multinodular and circumscribed and consisted of nests of bland, round cells admixed with hyalinized collagenous bands containing spindled cells. Hemorrhage and cystic change were often present; necrosis was absent. All were diffusely S100 protein/SOX10-positive; 4 of 5 were CD99-negative. One tested case was strongly positive for NKX2.2. A variety of other tested markers were either focally positive (glial fibrillary acidic protein, p63) or negative. Molecular genetic results were as follows: EWSR1 exon 7::FLI1 exon 8, EWSR1 exon 11::FLI1 exon 5, EWSR1 exon 11::FLI1 exon 6, EWSR1 exon 7::FLI1 exon 6, and EWSR1 exon 10::FLI1 exon 6. Methylation profiling (3 cases) showed these to form a unique cluster, distinct from Ewing sarcoma. All patients underwent excision with negative margins; one received 1 cycle of chemotherapy. Clinical follow-up showed all patients to be alive without disease (median: 17 months; range: 11-62 months). Despite similar gene fusions, the morphologic, immunohistochemical, epigenetic, and clinical features of these unique EWSR1::FLI1-fused neoplasms of the skin and subcutis differ substantially from Ewing sarcoma. Interestingly, EWSR1 rearrangements involved exons 10 or 11, only rarely seen in Ewing sarcoma, in a majority of cases. Superficial neurocristic EWSR1::FLI1 fusion tumors should be rigorously distinguished from true cutaneous Ewing sarcomas.

Be careful what you wish for: Individuals perceived to desire status are afforded less status.

In multiple studies, we found that people who are viewed as possessing a stronger desire for status are, ironically, afforded lower status by others. Coworkers who were viewed as having a higher (versus lower) desire for status (Study 1a and 1b), and individuals who were described as having a higher desire for status (versus a lower desire for status or no information), were afforded lower status (Studies 2, 3a, and 3b). Mediation analyses and an experimental manipulation of the mediator (Study 3a and 3b) suggested that the observed negative effect of desire for status on status was mediated primarily by perceptions of low prosociality. These findings have important implications for status organizing processes in groups.

Prospective Evaluation of the Kaiser Permanente Prostate Cancer Risk Calculator in Biopsy-Naïve Men with Mild PSA Elevations.

INTRODUCTION: Our goal was to assess the impact of providing prostate cancer risk estimates to patients and urologists among biopsy-naïve men with mild PSA elevations. METHODS: This prospective intervention study was conducted in urology departments in Kaiser Permanente Northern California among biopsy-naïve men with mild PSA elevations (<10 ng/mL) between March 2021 and March 2023. The intervention was providing prostate cancer risk estimates for intermediate-/high-grade cancer (Grade Groups 2-5) and any cancer to patients and urologists using our previously validated risk calculator. Biopsy outcomes were compared to a historical comparison group biopsied between January 2016 and December 2019. RESULTS: Over 24 months, the risk calculator was used to estimate risk for 1962 men, of whom 1455 (74%) accepted the biopsy. The men who accepted the biopsy had higher predicted intermediate-/high-grade cancer risks (median 24%, interquartile range [IQR] 17%-31%, vs 20%, IQR 14%-29%; P < .0001) and higher predicted risks for any cancer (median 48%, IQR 40%-56%, vs 45%, IQR 37%-53%, respectively; P < .0001) than those who declined the biopsy. Compared to the historical group, use of the risk calculator resulted in a biopsy population enriched with intermediate-/high-grade cancer: 29% vs 25%; similar rates of low-grade cancer: 24% vs 24%; and fewer negative biopsies: 47% vs 51%, respectively; overall P = .013. CONCLUSIONS: In biopsy-naïve men with mild PSA elevations, use of this risk calculator resulted in a biopsy population that had more intermediate-/high-grade cancer and fewer negative biopsies compared to a historical group.

Optimizing Amorphous Molybdenum Sulfide Thin Film Electrocatalysts: Trade-Off between Specific Activity and Microscopic Porosity.

Amorphous molybdenum sulfide (a-MoSx) is a promising candidate to replace noble metals as electrocatalysts for the hydrogen evolution reaction (HER) in electrochemical water splitting. So far, understanding of the activity of a-MoSx in relation to its physical (e.g., porosity) and chemical (e.g., Mo/S bonding environments) properties has mostly been derived from bulk electrochemical measurements, which provide limited information about electrode materials that possess microscopic structural heterogeneities. To overcome this limitation, herein, scanning electrochemical cell microscopy (SECCM) has been deployed to characterize the microscopic electrochemical activity of a-MoSx thin films (ca. 200 nm thickness), which possess a significant three-dimensional structure (i.e., intrinsic porosity) when produced by electrodeposition. A novel two-step SECCM protocol is designed to quantitatively determine spatially resolved electrochemical activity and electrochemical surface area (ECSA) within a single, high-throughput measurement. It is shown for the first time that although the highest surface area (e.g., most porous) regions of the a-MoSx film possess the highest total activity (measured by the electrochemical current), they do not possess the highest specific activity (measured by the ECSA-normalized current density). Instead, the areas of highest specific activity are localized at/around circular structures, coined "pockmarks", which are tens to hundreds of micrometers in size and ubiquitous to a-MoSx films produced by electrodeposition. By coupling this technique with structural and elemental composition analysis techniques (scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy) and correlating ECSA with activity and specific activity across SECCM scans, this work furthers the understanding of structure-activity relations in a-MoSx and highlights the importance of local measurements for the systematic and rational design of thin film catalyst materials.

The effect of teprotumumab infusion on ocular alignment in patients with symptomatic thyroid eye disease.

BACKGROUND: Thyroid eye disease (TED) can result in proptosis and ocular misalignment, leading to eye pain, diplopia, and vision loss. Teprotumumab, a humanized antibody against insulin-like growth factor 1 receptor, was approved in 2020 for the treatment of TED. The purpose of this study was to describe the effect of a full course of teprotumumab on ocular misalignment. METHODS: The medical records of patients who underwent treatment with teprotumumab for active moderate-to-severe TED at a single institution from April 2020 to September 2023 were reviewed retroactively. Sensorimotor examination was performed at each visit using simultaneous prism-cover testing. Demographic information and previous history of radioactive iodine, steroids, strabismus surgery, and smoking were extracted from the record for analysis. RESULTS: A total of 19 patients were treated during the study period, of whom 11 had strabismus and diplopia. The initial absolute horizontal misalignment in these 11 was 6.0Δ ± 1.5Δ, vertical misalignment was 7.7Δ ± 2.4Δ, and total misalignment was 11.5Δ ± 2.0Δ. On completion of treatment, these measurements decreased by 2.0Δ ± 1.5Δ, 2.2Δ ± 1.0Δ, and 3.2Δ ± 1.6Δ, respectively (P = 0.10, 0.02, and 0.04, resp.). Eight patients (73%) had a decrease in their strabismus, and 5 (46%) reported complete resolution of their diplopia at the final visit. No factors were predictive of which patients would have resolution of their misalignment. Of the remaining 3 patients who had no improvement in ocular alignment, 2 (66%) underwent strabismus surgery. Of the 8 patients with improvement of strabismus, only a single patient (13%) underwent strabismus surgery for persistent diplopia. CONCLUSIONS: In our study cohort, a full course of teprotumumab coincided with complete resolution of diplopia in 46% of patients and a decrease in strabismus in 73% of patients.

A nationwide, population-based study on specialized care for acute heart failure throughout the COVID-19 pandemic.

AIMS: The COVID-19 pandemic disrupted the delivery of care for patients with heart failure (HF), leading to fewer HF hospitalizations and increased mortality. However, nationwide data on quality of care and long-term outcomes across the pandemic are scarce. METHODS AND RESULTS: We used data from the National Heart Failure Audit (NHFA) linked to national records for hospitalization and deaths. We compared pre-COVID (2018-2019), COVID (2020), and late/post-COVID (2021-2022) periods. Data for 227 250 patients admitted to hospital with HF were analysed and grouped according to the admission year and the presence of HF with (HFrEF) or without reduced ejection fraction (non-HFrEF). The median age at admission was 81 years (interquartile range 72-88), 55% were men (n = 125 975), 87% were of white ethnicity (n = 102 805), and 51% had HFrEF (n = 116 990). In-hospital management and specialized cardiology care were maintained throughout the pandemic with an increasing percentage of patients discharged on disease-modifying medications over time (p < 0.001). Long-term outcomes improved over time (hazard ratio [HR] 0.92, 95% confidence interval [CI] 0.90-0.95, p < 0.001), mainly driven by a reduction in cardiovascular death. Receiving specialized cardiology care was associated with better long-term outcomes both for those who had HFrEF (HR 0.79, 95% CI 0.77-0.82, p < 0.001) and for those who had non-HFrEF (HR 0.87, 95% CI 0.85-0.90, p < 0.001). CONCLUSIONS: Despite the disruption of healthcare systems, the clinical characteristics of patients admitted with HF were similar and the overall standard of care was maintained throughout the pandemic. Long-term survival of patients hospitalized with HF continued to improve after COVID-19, especially for HFrEF.

Increasing Adoption of Left Atrial Appendage Occlusion in Isolated Coronary Artery Bypass Grafting.

BACKGROUND: Recent randomized trial data showed fewer strokes with left atrial appendage occlusion (LAAO) following cardiac surgery in patients with atrial fibrillation. We developed a quality initiative to increase LAAO adoption. METHODS: Among 11,099 patients undergoing isolated CABG between January 2019-March 2021 at 33 hospitals in Michigan, those with atrial fibrillation undergoing first-time, on-pump CABG were eligible (n=1,241). A goal LAAO rate of 75% was selected as a quality improvement target through a statewide collaborative. An interrupted time series analysis evaluated the change in LAAO rate before (January-December 2019) versus after (January 2020-March 2021) implementation. RESULTS: Implementation of the quality metric improved LAAO rate from 61% (357/581) before to 79% (520/660) after implementation (p<0.001). Compared to patients not undergoing concomitant LAAO, LAAO patients (71%, 877/1,241) were older, more frequently male, and had a lower STS-PROM (2.9±3.5% vs. 3.7±5.7%, p=0.003), while other baseline characteristics including CHA2DS2-VASc scores were similar. Mean bypass and cross-clamp times were 7 and 6 minutes longer, respectively, in the LAAO group among those who did not undergo concomitant ablation. Operative mortality, major morbidity, blood product administration, and thromboembolic events were similar between groups. Interrupted time series analysis showed a significant increase in LAAO rate after implementation (p=0.009). CONCLUSIONS: LAAO in patients with atrial fibrillation undergoing isolated CABG did not add operative risk versus isolated CABG without LAAO. A statewide quality improvement initiative was successful in increasing the rate of concomitant LAAO and could be further evaluated as a potential quality metric in cardiac surgery.

Non-hemorrhagic cerebellar contrast enhancement on intraoperative MRI during a supratentorial glioma resection: Concerning finding of no significance.

Intraoperative magnetic resonance imaging (iMRI) is a powerful tool used to verify maximal safe resection of gliomas. However, unsuspected new or incidental findings can present difficult clinical scenarios. Here we present a case of a large supratentorial glioma resection where new, incidental bilateral cerebellar hemispheric enhancement was noted on iMRI. A 52-year-old male with a large intra-axial mass spanning the right temporal and parietal lobes underwent a craniotomy for tumor resection utilizing iMRI. Imaging displayed new, remote, bilateral cerebellar enhancement. Upon completion of surgery, the patient was extubated and was at his neurological baseline. An immediate CT scan showed no abnormalities in the cerebellum, and the duration of his hospital stay was unaffected by this finding. An MRI 24 hours after the procedure demonstrated complete resolution of the enhancement. New, remote contrast enhancement in the cerebellum raises concerns for the potentially emergent, well-defined pathology known as remote cerebellar hemorrhage (RCH). However, here we describe a case where these findings turned out to be clinically insignificant, CT-negative, and self-limiting. Therefore, here we call this finding remote non-hemorrhagic cerebellar contrast enhancement (RNHCCE) to differentiate it from RCE, and we discuss nuances and management considerations for differentiating the two.

Divergent ecological selection maintains species boundaries despite gene flow in a rare endemic tree, Quercus acerifolia (maple-leaf oak).

Strong gene flow from outcrossing relatives tends to blur species boundaries, while divergent ecological selection can counteract gene flow. To better understand how these two forces affect the maintenance of species boundaries, we focused on a species complex including a rare species, maple-leaf oak (Quercus acerifolia), which is found in only four disjunct ridges in Arkansas. Its limited range and geographic proximity to co-occurring close relatives create the possibility for genetic swamping. In this study, we gathered genome-wide SNPs using restriction-site associated DNA sequencing (RADseq) from 190 samples of Q. acerifolia and three of its close relatives, Q. shumardii, Q. buckleyi, and Q. rubra. We found that Q. shumardii and Q. acerifolia are reciprocally monophyletic with low support, suggesting incomplete lineage sorting, introgression between Q. shumardii and Q. acerifolia, or both. Analyses that model allele distributions demonstrate that admixture contributes strongly to this pattern. Populations of Q. acerifolia experience gene flow from Q. shumardii and Q. rubra, but we found evidence that divergent selection is likely maintaining species boundaries: 1) ex situ collections of Q. acerifolia have a higher proportion of hybrids compared to the mature trees of the wild populations, suggesting ecological selection against hybrids at the seed/seedling stage; 2) ecological traits co-vary with genomic composition; and 3) Q. acerifolia shows genetic differentiation at loci hypothesized to influence tolerance of radiation, drought, and high temperature. Our findings strongly suggest that in maple-leaf oak, selection results in higher divergence at regions of the genome despite gene flow from close relatives.