Citations

Abstract: Background: Allergic contact dermatitis is a common, pruritic, debilitating skin disease, affecting at least 20% of the population. Objective: To prospectively validate a computer vision algorithm across all Fitzpatrick skin types. Methods: Each participant was exposed to 10 allergens. The reference criterion was obtained 5 days after initial patch placement by a board-certified dermatologist. The algorithm processed photographs of the test site obtained on Day 5. Human performance in reading the photographs was also evaluated. Results: A total of 206 evaluable participants [mean age 39 years, 66% (136/206) female, and 47% with Fitzpatrick skin types IV–VI] completed testing. Forty-two percent (87/206) of participants experienced 1 or more allergic reaction resulting in a total of 132 allergic reactions. The model provided high discrimination (AUROC 0.86, 95% CI: 0.82–0.90) and specificity (93%, 95% CI: 92%–94%) but with lower sensitivity (58%, 95% CI: 49%–67%). Human performance interpreting the photographs ranged from providing similar performance to the algorithm to providing superior performance when combined across readers. There were no serious adverse events. Conclusions: The combination of a smartphone capture of patch testing sites with deep learning yielded high discrimination across a diverse sample.

In the Spring of 2020, the United States of America (USA) deployed COVID-19 convalescent plasma (CCP) to treat hospitalized patients. Over 500,000 patients were treated with CCP during the first year of the pandemic. In this study, we estimated the number of actual inpatient lives saved by CCP treatment in the United States of America based on CCP weekly use, weekly national mortality data, and CCP mortality reduction data from meta-analyses of randomized controlled trials and real-world data. We also estimate the potential number of lives saved if CCP had been deployed for 100% of hospitalized patients or used in 15 to 75% of outpatients. Depending on the assumptions modeled in stratified analyses, we estimated that CCP saved between 16,476 and 66,296 lives. The CCP ideal use might have saved as many as 234,869 lives and prevented 1,136,133 hospitalizations. CCP deployment was a successful strategy for ameliorating the impact of the COVID-19 pandemic in the USA. This experience has important implications for convalescent plasma use in future infectious disease emergencies.

BACKGROUND: Systemic arterial compliance and venous capacitance are typically impaired in patients with heart failure with preserved ejection fraction (HFpEF), contributing to hemodynamic congestion with stress. Sodium-glucose cotransporter-2 inhibitors reduce hemodynamic congestion and improve clinical outcomes in patients with HFpEF, but the mechanisms remain unclear. This study tested the hypothesis that Dapagliflozin would improve systemic arterial compliance and venous capacitance during exercise in patients with HFpEF. METHODS: In this secondary analysis from the CAMEO-DAPA trial (Cardiac and Metabolic Effects of Dapagliflozin in Heart Failure With Preserved Ejection Fraction Trial), 37 patients with HFpEF (mean age 68 ± 9 years, women 65%) underwent invasive hemodynamic exercise testing with simultaneous echocardiography at baseline and following treatment for 24 weeks with Dapagliflozin or placebo. Radial artery pressure (BP) was measured continuously using a fluid-filled catheter with transformation to aortic pressure, central hemodynamics were measured using high-fidelity micromanometers, and stressed blood volume was estimated from hemodynamic indices fit to a comprehensive cardiovascular model. RESULTS: There was no statistically significant effect of Dapagliflozin on resting BP, but Dapagliflozin reduced systolic BP during peak exercise (estimated treatment difference [ETD], −18.8 mm Hg [95% CI, −33.9 to −3.7] P =0.016). Reduction in BP was related to improved exertional total arterial compliance (ETD, 0.06 mL/mm Hg/m 2 [95% CI, 0.003–0.11] P =0.039) and aortic root characteristic impedance (ETD, −2.6 mm Hg/mL*sec [95% CI: −5.1 to −0.03] P =0.048), with no significant effect on systemic vascular resistance. Dapagliflozin reduced estimated stressed blood volume at rest and during peak exercise (ETD, −292 mm Hg [95% CI, −530 to −53] P =0.018), and improved venous capacitance evidenced by a decline in ratio of estimated stressed blood volume to total blood volume (ETD, −7.3% [95% CI, −13.3 to −1.3] P =0.020). Each of these effects of Dapagliflozin at peak exercise were also observed during matched 20W exercise intensity. Improvements in total arterial compliance and estimated stressed blood volume were correlated with decreases in body weight, and reduction in systolic BP with treatment was correlated with the change in estimated stressed blood volume during exercise (r=0.40, P =0.019). Decreases in BP were correlated with reduction in pulmonary capillary wedge pressure during exercise (r=0.56, P <0.001). CONCLUSIONS: In patients with HFpEF, treatment with Dapagliflozin improved systemic arterial compliance and venous capacitance during exercise, while reducing aortic characteristic impedance, suggesting a reduction in arterial wall stiffness. These vascular effects may partially explain the clinical benefits with sodium-glucose cotransporter-2 inhibitors in HFpEF. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT04730947.

ImportanceIncreases in pulmonary capillary wedge pressure (PCWP) during exercise reduce pulmonary artery (PA) compliance, increase pulsatile right ventricular (RV) afterload, and impair RV-PA coupling in patients with heart failure with preserved ejection fraction (HFpEF). The effects of the sodium-glucose cotransporter 2 (SGLT2) inhibitor dapagliflozin on pulmonary vascular properties and RV-PA coupling are unknown.ObjectiveTo test the effect of dapagliflozin on right ventricular performance and pulmonary vascular load during exertion in HFpEF.Design, Setting, and ParticipantsEvaluation of the Cardiac and Metabolic Effects of Dapagliflozin in Heart Failure With Preserved Ejection Fraction (CAMEO-DAPA) randomized clinical trial demonstrated improvement in PCWP at rest and exercise over 24 weeks with dapagliflozin compared with placebo with participants recruited between February 2021 and May 2022. This secondary analysis evaluates the effects of dapagliflozin on pulsatile pulmonary vascular load and RV-PA coupling using simultaneous echocardiography and high-fidelity invasive hemodynamic testing with exercise. This was a single-center study including patients with hemodynamically confirmed HFpEF with exercise PCWP of 25 mm Hg or greater.InterventionsDapagliflozin or placebo for 24 weeks.Main Outcomes and MeasuresPulsatile pulmonary vascular load (PA compliance and elastance) and right ventricular performance (PA pulsatility index, RV systolic velocity [s′]/PA mean) during rest and exercise.ResultsAmong 37 randomized participants (mean [SD] age, 67.4 [8.5] years; 25 female [65%]; mean [SD] body mass index, 34.9 [6.7]; calculated as weight in kilograms divided by height in meters squared), there was no effect of dapagliflozin on PA loading or RV-PA interaction at rest. However, with exercise, dapagliflozin improved PA compliance (placebo-corrected mean difference, 0.57 mL/mm Hg; 95% CI, 0.11-1.03 mL/mm Hg; P = .02) and decreased PA elastance (stiffness; −0.17 mm Hg/mL; 95% CI, −0.28 to −0.07 mm Hg/mL; P = .001). RV function during exercise improved, with increase in PA pulsatility index (0.33; 95% CI, 0.08-0.59; P = .01) and increase in exercise RV s′ indexed to PA pressure (0.09 cm·s−1/mm Hg; 95% CI, 0.02-0.16 cm·s−1/mm Hg; P = .01). Improvements in pulsatile RV load and RV-PA coupling were correlated with reduction in right atrial (RA) pressure (PA elastance Pearson r = 0.55; P =.008; RV s′/PA elastance Pearson r = −0.60; P =.002) and PCWP (PA elastance Pearson r = 0.58; P &amp;lt;.001; RV s′/PA elastance Pearson r = −0.47; P = .02). Dapagliflozin increased resistance-compliance time (dapagliflozin, median [IQR] change, 0.06 [0.03-0.15] seconds; placebo, median [IQR] change, 0.01 [−0.02 to 0.05] seconds; P =.046), resulting in higher PA compliance for any exercise pulmonary vascular resistance.Conclusions and RelevanceResults of this randomized clinical trial reveal that treatment with dapagliflozin for 24 weeks reduced pulsatile pulmonary vascular load and enhanced dynamic RV-PA interaction during exercise in patients with HFpEF, findings that are related to the magnitude of PCWP reduction. Benefits on dynamic right ventricular–pulmonary vascular coupling may partially explain the benefits of SGLT2 inhibitors in HFpEF.Trial RegistrationClinicalTrials.gov Identifier: NCT04730947

Abstract Parkinson’s disease (PD) is marked by degeneration in the nigrostriatal dopaminergic pathway, affecting motor control via complex changes in the cortico-basal ganglia-thalamic motor network, including the primary motor cortex (M1). The modulation of M1 neuronal activity by dopaminergic inputs, particularly from the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc), plays a crucial role in PD pathophysiology. This study investigates how nigrostriatal dopaminergic degeneration influences M1 neuronal activity in rats using in vivo calcium imaging. Histological analysis confirmed dopaminergic lesion severity, with high lesion level rats showing significant motor deficits. Levodopa treatment improved fine motor abilities, particularly in high lesion level rats. Analysis of M1 calcium signals based on dopaminergic lesion severity revealed distinct M1 activity patterns. Animals with low dopaminergic lesion showed increased calcium events, while high lesion level rats exhibited decreased activity, partially restored by levodopa. These findings suggest that M1 activity is more sensitive to transient fluctuations in dopaminergic transmission, rather than to chronic high or low dopaminergic signaling. This study underscores the complex interplay between dopaminergic signaling and M1 neuronal activity in PD symptoms development. Further research integrating behavioral and calcium imaging data can elucidate mechanisms underlying motor deficits and therapeutic responses in PD.

Abstract Aims Mobile devices such as smartphones and watches can now record single-lead electrocardiograms (ECGs), making wearables a potential screening tool for cardiac and wellness monitoring outside of healthcare settings. Because friends and family often share their smart phones and devices, confirmation that a sample is from a given patient is important before it is added to the electronic health record. Methods and results We sought to determine whether the application of Siamese neural network would permit the diagnostic ECG sample to serve as both a medical test and biometric identifier. When using similarity scores to discriminate whether a pair of ECGs came from the same patient or different patients, inputs of single-lead and 12-lead medians produced an area under the curve of 0.94 and 0.97, respectively. Conclusion The similar performance of the single-lead and 12-lead configurations underscores the potential use of mobile devices to monitor cardiac health.

Importance Factors associated with clinical heterogeneity in Alzheimer disease (AD) lay along a continuum hypothesized to associate with tangle distribution and are relevant for understanding glial activation considerations in therapeutic advancement. Objectives To examine clinicopathologic and neuroimaging characteristics of disease heterogeneity in AD along a quantitative continuum using the corticolimbic index (CLix) to account for individuality of spatially distributed tangles found at autopsy. Design, Setting, and Participants This cross-sectional study was a retrospective medical record review performed on the Florida Autopsied Multiethnic (FLAME) cohort accessioned from 1991 to 2020. Data were analyzed from December 2022 to December 2023. Structural magnetic resonance imaging (MRI) and tau positron emission tomography (PET) were evaluated in an independent neuroimaging group. The FLAME cohort includes 2809 autopsied individuals; included in this study were neuropathologically diagnosed AD cases (FLAME-AD). A digital pathology subgroup of FLAME-AD cases was derived for glial activation analyses. Main Outcomes and Measures Clinicopathologic factors of heterogeneity that inform patient history and neuropathologic evaluation of AD; CLix score (lower, relative cortical predominance/hippocampal sparing vs higher, relative cortical sparing/limbic predominant cases); neuroimaging measures (ie, structural MRI and tau-PET). Results Of the 2809 autopsied individuals in the FLAME cohort, 1361 neuropathologically diagnosed AD cases were evaluated. A digital pathology subgroup included 60 FLAME-AD cases. The independent neuroimaging group included 93 cases. Among the 1361 FLAME-AD cases, 633 were male (47%; median [range] age at death, 81 [54-96] years) and 728 were female (53%; median [range] age at death, 81 [53-102] years). A younger symptomatic onset (Spearman ρ = 0.39, P &amp;lt; .001) and faster decline on the Mini-Mental State Examination (Spearman ρ = 0.27; P &amp;lt; .001) correlated with a lower CLix score in FLAME-AD series. Cases with a nonamnestic syndrome had lower CLix scores (median [IQR], 13 [9-18]) vs not (median [IQR], 21 [15-27]; P &amp;lt; .001). Hippocampal MRI volume (Spearman ρ = −0.45; P &amp;lt; .001) and flortaucipir tau-PET uptake in posterior cingulate and precuneus cortex (Spearman ρ = −0.74; P &amp;lt; .001) inversely correlated with CLix score. Although AD cases with a CLix score less than 10 had higher cortical tangle count, we found lower percentage of CD68-activated microglia/macrophage burden (median [IQR], 0.46% [0.32%-0.75%]) compared with cases with a CLix score of 10 to 30 (median [IQR], 0.75% [0.51%-0.98%]) and on par with a CLix score of 30 or greater (median [IQR], 0.40% [0.32%-0.57%]; P = .02). Conclusions and Relevance Findings show that AD heterogeneity exists along a continuum of corticolimbic tangle distribution. Reduced CD68 burden may signify an underappreciated association between tau accumulation and microglia/macrophages activation that should be considered in personalized therapy for immune dysregulation.

Abstract Context Circulating lactate concentration is an important determinant of exercise tolerance. Objective This work aimed to determine the role of hyperglycemia on lactate metabolism during exercise in individuals with type 1 diabetes (T1D). Methods The protocol at the University of Virginia compared 7 T1D participants and 7 participants without diabetes (ND) at euglycemia (5.5 mM) or hyperglycemia (9.2 mM) in random order in T1D and at euglycemia in ND. Intervention included [1-13C] lactate infusion, exercise at 65% maximal oxygen uptake (VO2max), euglycemia, and hyperglycemia visits. The main outcome measure was lactate turnover before, during, and after 60 minutes of exercise at 65% VO2max. Results A 2-compartment model with loss only from the peripheral compartment described lactate kinetics. Volume of distribution of the accessible compartment was similar between T1D and ND individuals (P = .76) and concordant with plasma volume (∼40 mL/kg). Circulating lactate concentrations were higher (P &lt; .001) in T1D participants during exercise at hyperglycemia than euglycemia. Exercise-induced lactate appearance did not differ (P = .13) between hyperglycemia and euglycemia. However, lactate clearance (CL) was lower (P = .03) during hyperglycemia than euglycemia in T1D participants. There were no differences in any of the aforementioned parameters between T1D and ND participants during euglycemia. Conclusion Hyperglycemia modulates lactate metabolism during exercise by lowering CL, leading to higher circulating lactate concentrations in T1D individuals. This novel observation implies that exercise during hyperglycemia can lead to higher circulating lactate concentrations thus increasing the likelihood of reaching the lactate threshold sooner in T1D, and has high translational relevance both for providers and recreationally active people with T1D.