Theoretical prediction of closed-shell paramagnetism for scandium and yttrium hydride.

Following chemical intuition, one would expect that all closed-shell molecules are diamagnetic. However, it is known that this is not the case for some second-row hydrides with low-lying unoccupied π orbitals due to an unquenching of the total angular momentum in the presence of an external magnetic field. In this article, the transition-metal hydrides ScH and YH are investigated, assuming a similar unquenching effect involving low-lying unoccupied π and δ orbitals formed from the metal d orbitals rather than the p orbitals. We are comparing results obtained with various quantum-chemical methods (HF, CCSD, CCSD(T), CCSDT) and basis sets. The obtained positive values for the magnetizabilities clearly indicate paramagnetic behavior. Vibrational effects on the magnetizability tensor are also considered, but these effects are small and do not change the overall conclusion that both ScH and YH are further examples for closed-shell paramagnetism.

Mucosal correlates of protection after influenza viral challenge of vaccinated and unvaccinated healthy volunteers.

The induction of systemic antibody titers against hemagglutinin has long been the main focus of influenza vaccination strategies, but mucosal immunity has also been shown to play a key role in the protection against respiratory viruses. By vaccinating and challenging healthy volunteers, we demonstrated that inactivated influenza vaccine (IIV) modestly reduced the rate of influenza while predominantly boosting serum antibody titers against hemagglutinin (HA) and HA stalk, a consequence of the low neuraminidase (NA) content of IIV and the intramuscular route of administration. The viral challenge induced nasal and serum responses against both HA and NA. Correlations between mucosal IgA and serum IgG against specific antigens were low, whether before or after challenge, suggesting a compartmentalization of immune responses. Even so, volunteers who developed viral shedding for multiple days had lower baseline titers across both systemic and mucosal compartments as compared to those with no shedding or a single day of shedding. Regression analysis showed that pre-challenge HA inhibition titers were the most consistent correlate of protection across clinical outcomes combining shedding and symptoms, with NA inhibition titers and HA IgG levels only predicting the duration of shedding. Despite the inclusion of data from multiple binding and functional antibody assays against HA and NA performed on both serum and nasal samples, multivariate models were unable to account for the variability in outcomes, emphasizing our imperfect understanding of immune correlates in influenza and the importance of refining models with assessments of innate and cellular immune responses.IMPORTANCEThe devastating potential of influenza has been well known for over 100 years. Despite the development of vaccines since the middle of the 20th century, influenza continues to be responsible for substantial global morbidity and mortality. To develop next-generation vaccines with enhanced effectiveness, we must synthesize our understanding of the complex immune mechanisms culminating in protection. Our study outlines the differences in immune responses to influenza vaccine and influenza infection, identifying potential gaps in vaccine-induced immunity, particularly at the level of the nasal mucosa. Furthermore, this research underscores the need to refine our imperfect models while recognizing potential pitfalls in past and future attempts to identify and measure correlates of protection.

Dynamics of SARS-CoV-2 Seroprevalence in a Large US population Over a Period of 12 Months.

Due to a combination of asymptomatic or undiagnosed infections, the proportion of the United States population infected with SARS-CoV-2 was unclear from the beginning of the pandemic. We previously established a platform to screen for SARS-CoV-2 positivity across a representative proportion of the US population, from which we reported that almost 17 million Americans were estimated to have had undocumented infections in the Spring of 2020. Since then, vaccine rollout and prevalence of different SARS-CoV-2 variants have further altered seropositivity trends within the United States population. To explore the longitudinal impacts of the pandemic and vaccine responses on seropositivity, we re-enrolled participants from our baseline study in a 6- and 12- month follow-up study to develop a longitudinal antibody profile capable of representing seropositivity within the United States during a critical period just prior to and during the initiation of vaccine rollout. Initial measurements showed that, since July 2020, seropositivity elevated within this population from 4.8% at baseline to 36.2% and 89.3% at 6 and 12 months, respectively. We also evaluated nucleocapsid seropositivity and compared to spike seropositivity to identify trends in infection versus vaccination relative to baseline. These data serve as a window into a critical timeframe within the COVID-19 pandemic response and serve as a resource that could be used in subsequent respiratory illness outbreaks.

Heart rate characteristic based modelling of atrial fibrillatory rate using implanted cardiac monitor data.

Objective. The objective of the present study is to investigate the feasibility of using heart rate characteristics to estimate atrial fibrillatory rate (AFR) in a cohort of atrial fibrillation (AF) patients continuously monitored with an implantable cardiac monitor. We will use a mixed model approach to investigate population effect and patient specific effects of heart rate characteristics on AFR, and will correct for the effect of previous ablations, episode duration, and onset date and time.Approach. The f-wave signals, from which AFR is estimated, were extracted using a QRST cancellation process of the AF episodes in a cohort of 99 patients (67% male; 57 ± 12 years) monitored for 9.2(0.2-24.3) months as median(min-max). The AFR from 2453 f-wave signals included in the analysis was estimated using a model-based approach. The association between AFR and heart rate characteristics, prior ablations, and episode-related features were modelled using fixed-effect and mixed-effect modelling approaches.Main results. The mixed-effect models had a better fit to the data than fixed-effect models showing h.c. of determination (R2 = 0.49 versusR2 = 0.04) when relating the variations of AFR to the heart rate features. However, when correcting for the other factors, the mixed-effect model showed the best fit (R2 = 0.04). AFR was found to be significantly affected by previous catheter ablations (p< 0.05), episode duration (p< 0.05), and irregularity of theRRinterval series (p< 0.05).Significance. Mixed-effect models are more suitable for AFR modelling. AFR was shown to be faster in episodes with longer duration, less organizedRRintervals and after several ablation procedures.

Atrial fibrillation episode patterns as predictor of clinical outcome of catheter ablation.

Methods for characterization of atrial fibrillation (AF) episode patterns have been introduced without establishing clinical significance. This study investigates, for the first time, whether post-ablation recurrence of AF can be predicted by evaluating episode patterns. The dataset comprises of 54 patients (age 56 ± 11 years; 67% men), with an implantable cardiac monitor, before undergoing the first AF catheter ablation. Two parameters of the alternating bivariate Hawkes model were used to characterize the pattern: AF dominance during the monitoring period (log(mu)) and temporal aggregation of episodes (beta1). Moreover, AF burden and AF density, a parameter characterizing aggregation of AF burden, were studied. The four parameters were computed from an average of 29 AF episodes before ablation. The risk of AF recurrence after catheter ablation using the Hawkes parameters log(mu) and beta1, AF burden, and AF density was evaluated. While the combination of AF burden and AF density is related to a non-significant hazard ratio, the combination of log(mu) and beta1 is related to a hazard ratio of 1.95 (1.03-3.70; p < 0.05). The Hawkes parameters showed increased risk of AF recurrence within 1 year after the procedure for patients with high AF dominance and high episode aggregation and may be used for pre-ablation risk assessment.

Repeatability and reproducibility of MRI-radiomic features: A phantom experiment on a 1.5 T scanner.

PURPOSE: Aim of this study is to assess the repeatability of radiomic features on magnetic resonance images (MRI) and their stability to variations in time of repetition (TR), time of echo (TE), slice thickness (ST), and pixel spacing (PS) using vegetable phantoms. METHODS: The organic phantom was realized using two cucumbers placed inside a cylindrical container, and the analysis was performed using T1-weighted (T1w), T2-weighted (T2w), and diffusion-weighted images. One dataset was used to test the repeatability of the radiomic features, whereas other four datasets were used to test the sensitivity of the different MRI sequences to image acquisition parameters (TR, TE, ST, and PS). Four regions of interest (ROIs) were segmented: two for the central part of each cucumber and two for the external parts. Radiomic features were extracted from each ROI using Pyradiomics. To assess the effect of preprocessing on the reduction of variability, features were extracted both before and after the preprocessing. The coefficient of variation (CV) and intra-class correlation coefficient (ICC) were used to evaluate variability. RESULTS: The use of intensity standardization increased the stability for the first-order statistics features. Shape and size features were always stable for all the analyses. Textural features were particularly sensitive to changes in ST and PS, although some increase in stability could be obtained by voxel size resampling. When images underwent image preprocessing, the number of stable features (ICC > 0.75 and mean absolute CV < 0.3) was 33 for apparent diffusion coefficient (ADC), 52 for T1w, and 73 for T2w. CONCLUSIONS: The most critical source of variability is related to changes in voxel size (either caused by changes in ST or PS). Preprocessing increases features stability to both test-retest and variation of the image acquisition parameters for all the types of analyzed MRI (T1w, T2w, and ADC), except for ST.

A new bipolar device for sealing and cutting: ex and in vivo studies for performance evaluation.

INTRODUCTION: A novel multipurpose bipolar radiofrequency instrument, the Erbe Dissector (EDS), which simultaneously seals and cuts tissue, was developed. Ex vivo sealing rate and time, burst pressure, jaw temperature and thermal spread were studied in porcine renal arteries. MATERIAL AND METHODS: In vivo, 13 surgical tasks were performed in two pigs: beside sealing rate and time, overall performance in sharp and blunt dissection, tissue sticking, hemostasis, precision, etc., were evaluated by four surgeons compared with ENSEAL G2 (EG2) using surveys on a Likert scale (1 = very poor; 5 = very good). RESULTS: Ex vivo, the EDS sealing rate was 91.7% (33/36 arteries) at an average sealing time of 2.1 s (range 1.7-2.8) and a burst pressure of 1040 ± 350 mmHg. The maximum jaw temperature was 87 ± 4 °C and the mean lateral thermal spread was 0.8 ± 0.2 mm. In vivo, the sealing rate for arteries and veins was 92.6% (50/54) and the median seal and cut time was 1.6 s (range: 1.3-2.9). The average EDS performance score across all tasks was 4.4 ± 0.6 Likert points. For five shared tasks, EDS was better than EG2 (4.4 ± 0.5 versus 3.4 ± 0.6 Likert points; p = 0.016). CONCLUSIONS: EDS seals and cuts arteries and veins rapidly with good safety and user-friendliness.

Ensemble classification combining ResNet and handcrafted features with three-steps training.

Objective.This work presents an ECG classifier for variable leads as a contribution to the Computing in Cardiology Challenge/CinC Challenge 2021. It aims to integrate deep and classic machine learning features into a single model, exploring the proper structure and training procedure.Approach.From the initial 88 253 signals, only 84 210 were included. Low quality and unscored recordings were excluded. Three different database subsets of 40 365 recording each were created by dividing in three normal sinus rhythm and sinus bradycardia recordings. Each subset was used to train a different model with shared architecture integrated as an ensemble to provide the final classification through major voting. Models contained a deep branch composed of a modified ResNet with dilation convolutional layers and squeeze and excitation Block that took as input windowed ECG signals. This was concatenated with a wide branch that integrated 20 cardiac rhythm features into a fully connected 3-layered network. Three different training steps were studied: just the deep branch (D), wide integration and training (D+W), and a final fine tuning of the deep branch posterior to wide training (D+W+D).Main Results.Results obtained in a local test set formed by a stratified 12.5% split of the given full dataset were presented for 2-lead and 12-lead models. The best training method was the 3-step D + W + D procedure obtaining a challenge metric of 0.709 and 0.677 for 12 and 2-lead models respectively.Significance.Integration of handcrafted features and deep learning model not only may increase the generalization capacity of the network but also provide a path to add explicit information into the classification decision process. To the best of our knowledge this is the first work studying the training procedure to properly integrate both types of information for ECG signals classification.

Chemotherapy-induced Cardiac18F-FDG Uptake in Patients with Lymphoma: An Early Metabolic Index of Cardiotoxicity? / Aumento de Captação Cardíaca de 18F-FDG Induzida por Quimioterapia em Pacientes com Linfoma: Um Marcador Precoce de Cardiotoxicidade?

BACKGROUND: It is uncertain whether myocardial fluorodeoxyglucose uptake occurs solely due to physiological features or if it represents a metabolic disarrangement under chemotherapy. OBJECTIVE: To investigate the chemotherapy effects on the heart of patients with lymphoma by positron emission tomography associated with computed tomography scans (PET/CT) with 2-deoxy-2[18F] fluoro-D-glucose (18F-FDG PET/CT) before, during and/or after chemotherapy. METHODS: Seventy patients with lymphoma submitted to18F-FDG PET/CT were retrospectively analyzed. The level of significance was 5%.18F-FDG cardiac uptake was assessed by three measurements: left ventricular maximum standardized uptake value (SUVmax), heart to blood pool (aorta) ratio, and heart to liver ratio in all the exams. Body weight, fasting blood sugar, post-injection time, and the injected dose of18F-FDG between the scans were also compared. RESULTS: Mean age was 50.4 ± 20.1 years and 50% was female. The analysis was carried out in two groups: baseline vs. interim PET/CT, and baseline vs. post-therapy PET/CT. There was no significant difference in clinical variables or protocol scans variables. We observed an increase in left ventricular (LV) SUVmax from 3.5±1.9 (baseline) to 5.6±4.0 (interim), p=0.01, and from 4.0±2.2 (baseline) to 6.1±4.2 (post-therapy), p<0.001. A percentage increase ≥30% of LV SUVmax occurred in more than half of the sample. The rise of cardiac SUV was accompanied by an increase in LV SUVmax/Aorta SUVmax and LV SUVmean/Liver SUVmean ratios. CONCLUSION: This study showed a clear increase in cardiac18F-FDG uptake in patients with lymphoma during and/or after chemotherapy. The literature corroborates with these findings and suggests that18F-FDG PET/CT is a sensitive and reliable imaging exam to detect early metabolic signs of cardiotoxicity.

FUNDAMENTO: Ainda não está estabelecido se a captação de fluorodesoxiglicose no miocárdio ocorre exclusivamente por características fisiológicas ou se representa um desarranjo metabólico causado pela quimioterapia. OBJETIVO: Investigar os efeitos da quimioterapia no coração dos pacientes com linfoma por tomografia por emissão de pósitrons associada a tomografia computadorizada (PET/CT) com 2-[18F]-fluoro-2-desoxi-D-glicose (18F-FDG PET/CT) antes, durante e/ou após a quimioterapia. MÉTODOS: Setenta pacientes com linfoma submetidos a 18F-FDG PET/CT foram retrospectivamente analisados. O nível de significância foi de 5%. A captação de 18F-FDG foi avaliada por três medidas: captação máxima no ventrículo esquerdo ( standardized uptake value , SUV max), razão SUV cardíaco / aorta e SUV cardíaco / SUV no fígado. Também foram comparados peso corporal, glicemia de jejum, tempo pós-injeção e dose administrada de 18F-FDG entre os exames. RESULTADOS: A idade média foi de 50,4 ± 20,1 anos e 50% dos pacientes eram mulheres. A análise foi realizada em dois grupos ­ PET/CT basal vs. intermediário e PET/CT basal vs pós-terapia. Não houve diferença significativa entre as variáveis clínicas e do protocolo dos exames entre os diferentes momentos avaliados. Nós observamos um aumento na SUV máxima no ventrículo esquerdo de 3,5±1,9 (basal) para 5,6±4,0 (intermediário), p=0,01, e de 4,0±2,2 (basal) para 6,1±4,2 (pós-terapia), p<0,001. Uma porcentagem de aumento ≥30% na SUV máxima no ventrículo esquerdo ocorreu em mais da metade da amostra. O aumento da SUV cardíaca foi acompanhado por um aumento na razão SUV máxima no ventrículo esquerdo / SUV máxima na aorta e SUV média no ventrículo esquerdo /SUV média no fígado. CONCLUSÃO: O estudo mostrou um aumento evidente na captação cardíaca de 18F-FDG em pacientes com linfoma, durante e após quimioterapia. A literatura corrobora com esses achados e sugere que a 18F-FDG PET/CT pode ser um exame de imagem sensível e confiável para detectar sinais metabólicos precoces de cardiotoxicidade.

GASTRIC TWIST AFTER SLEEVE GASTRECTOMY: A PROPOSAL FOR ENDOSCOPIC CLASSIFICATION.

OBJECTIVE: The twisting of the gastric tube is one of the main causes of persistent reflux and food intolerance after sleeve gastrectomy (SG). To date, there is no classification for gastric twist after SG. This study aimed to propose an endoscopic classification for this condition and outline the clinical profile of these patients with sleeve gastrectomy. METHODS: Patients in the postoperative period of SG presenting endoscopic findings of gastric twist were included. All patients underwent an esophagogastroduodenoscopy 12 months after SG. The classification proposed consists of three degrees: degree I: mild rotation of the staple line without relevant shrinkage of the gastric lumen; degree II: moderate rotation of the staple line, leading to a focal area of fixed narrowing that requires additional maneuvers for its transposition; and degree III: severe rotation of the staple line leading to stenosis, with increased difficulty for transposition or complete blockage. RESULTS: Out of 2,723 patients who underwent SG, 45 (1.6%) presented gastric twist. Most patients were female (85%), with mean age of 39±10.4 years. In all, 41 (91.1%) presented degree I, 3 (6.7%) presented degree II, and 1 (2.2%) had degree III. Most patients were asymptomatic (n=26). Vomiting was the most prevalent symptom (15.5%). Statistically significant correlation of twisting degrees was not observed for both the presence of symptoms and the degrees of esophagitis. CONCLUSION: Gastric twist after SG is rare, with generally mild and asymptomatic presentation. The endoscopic classification was not statistically related to clinical presentation but set the ground for further analysis.

Aumento de Captação Cardíaca de 18F-FDG Induzida por Quimioterapia em Pacientes com Linfoma: Um Marcador Precoce de Cardiotoxicidade? / Chemotherapy-induced Cardiac18F-FDG Uptake in Patients with Lymphoma: An Early Metabolic Index of Cardiotoxicity?

Resumo Fundamento Ainda não está estabelecido se a captação de fluorodesoxiglicose no miocárdio ocorre exclusivamente por características fisiológicas ou se representa um desarranjo metabólico causado pela quimioterapia. Objetivo Investigar os efeitos da quimioterapia no coração dos pacientes com linfoma por tomografia por emissão de pósitrons associada a tomografia computadorizada (PET/CT) com 2-[18F]-fluoro-2-desoxi-D-glicose (18F-FDG PET/CT) antes, durante e/ou após a quimioterapia. Métodos Setenta pacientes com linfoma submetidos a 18F-FDG PET/CT foram retrospectivamente analisados. O nível de significância foi de 5%. A captação de 18F-FDG foi avaliada por três medidas: captação máxima no ventrículo esquerdo ( standardized uptake value , SUV max), razão SUV cardíaco / aorta e SUV cardíaco / SUV no fígado. Também foram comparados peso corporal, glicemia de jejum, tempo pós-injeção e dose administrada de 18F-FDG entre os exames. Resultados A idade média foi de 50,4 ± 20,1 anos e 50% dos pacientes eram mulheres. A análise foi realizada em dois grupos - PET/CT basal vs. intermediário e PET/CT basal vs pós-terapia. Não houve diferença significativa entre as variáveis clínicas e do protocolo dos exames entre os diferentes momentos avaliados. Nós observamos um aumento na SUV máxima no ventrículo esquerdo de 3,5±1,9 (basal) para 5,6±4,0 (intermediário), p=0,01, e de 4,0±2,2 (basal) para 6,1±4,2 (pós-terapia), p<0,001. Uma porcentagem de aumento ≥30% na SUV máxima no ventrículo esquerdo ocorreu em mais da metade da amostra. O aumento da SUV cardíaca foi acompanhado por um aumento na razão SUV máxima no ventrículo esquerdo / SUV máxima na aorta e SUV média no ventrículo esquerdo /SUV média no fígado. Conclusão O estudo mostrou um aumento evidente na captação cardíaca de 18F-FDG em pacientes com linfoma, durante e após quimioterapia. A literatura corrobora com esses achados e sugere que a 18F-FDG PET/CT pode ser um exame de imagem sensível e confiável para detectar sinais metabólicos precoces de cardiotoxicidade.

Abstract Background It is uncertain whether myocardial fluorodeoxyglucose uptake occurs solely due to physiological features or if it represents a metabolic disarrangement under chemotherapy. Objective To investigate the chemotherapy effects on the heart of patients with lymphoma by positron emission tomography associated with computed tomography scans (PET/CT) with 2-deoxy-2[18F] fluoro-D-glucose (18F-FDG PET/CT) before, during and/or after chemotherapy. Methods Seventy patients with lymphoma submitted to18F-FDG PET/CT were retrospectively analyzed. The level of significance was 5%.18F-FDG cardiac uptake was assessed by three measurements: left ventricular maximum standardized uptake value (SUVmax), heart to blood pool (aorta) ratio, and heart to liver ratio in all the exams. Body weight, fasting blood sugar, post-injection time, and the injected dose of18F-FDG between the scans were also compared. Results Mean age was 50.4 ± 20.1 years and 50% was female. The analysis was carried out in two groups: baseline vs. interim PET/CT, and baseline vs. post-therapy PET/CT. There was no significant difference in clinical variables or protocol scans variables. We observed an increase in left ventricular (LV) SUVmax from 3.5±1.9 (baseline) to 5.6±4.0 (interim), p=0.01, and from 4.0±2.2 (baseline) to 6.1±4.2 (post-therapy), p<0.001. A percentage increase ≥30% of LV SUVmax occurred in more than half of the sample. The rise of cardiac SUV was accompanied by an increase in LV SUVmax/Aorta SUVmax and LV SUVmean/Liver SUVmean ratios. Conclusion This study showed a clear increase in cardiac18F-FDG uptake in patients with lymphoma during and/or after chemotherapy. The literature corroborates with these findings and suggests that18F-FDG PET/CT is a sensitive and reliable imaging exam to detect early metabolic signs of cardiotoxicity.

Association between ventricular repolarization parameters and cardiovascular death in patients of the SWISS-AF cohort.

BACKGROUND: The effect of the ventricular repolarization heterogeneity has not been systematically assessed in patients with atrial fibrillation (AF). Aim of this study is to assess ventricular repolarization heterogeneity as predictor of cardiovascular (CV) death and/or other CV events in patients with AF. METHODS: From the multicenter prospective Swiss-AF (Swiss Atrial Fibrillation) Cohort Study, we enrolled 1711 patients who were in sinus rhythm (995) or AF (716). Resting ECG recordings of 5-min duration were obtained at baseline. Parameters assessing ventricular repolarization were computed (QTc, Tpeak-Tend, J-Tpeak and V-index). RESULTS: During AF, the V-index was found repeatable (no differences when computed over the whole recording, on the first 2.5-min and on the last 2.5-min segments). During a mean follow-up time of 2.6 ± 1.0 years, 90 patients died for CV reasons. In bivariate Cox regression analysis (adjusted for age only), the V-index was associated with an increased risk of CV death, both in the subgroup of patients in sinus rhythm (SR) as well as those in AF. In multivariate analysis adjusted for clinical risk factors and medications, both prolonged QTc and V-index were independently associated with an increased risk of CV death (QTc: hazard ratio [HR] 2.78, 95% CI 1.79-4.32, p < 0.001; V-index: HR 1.73, 95% CI 1.12-2.69, p = 0.014). CONCLUSIONS: QTc and V-index, measured in a single 5-min ECG recording, were independent predictors of CV death in a cohort of patients with AF and might be a valuable tool for further risk stratification to guide patient management. Clinical Trial Identifier Swiss-AF study: NCT02105844.

Great Expectations of COVID-19 Herd Immunity.

There is a common preconception that reaching an estimated herd immunity threshold through vaccination will end the COVID-19 pandemic. However, the mathematical models underpinning this estimate make numerous assumptions that may not be met in the real world. The protection afforded by vaccines is imperfect, particularly against asymptomatic infection, which can still result in transmission and propagate pandemic viral spread. Immune responses wane and SARS-COV-2 has the capacity to mutate over time to become more infectious and resistant to vaccine elicited immunity. Human behavior and public health restrictions also vary over time and among different populations, impacting the transmissibility of infection. These ever-changing factors modify the number of secondary cases produced by an infected individual, thereby necessitating constant revision of the herd immunity threshold. Even so, vaccination remains a powerful strategy to slow down the pandemic, save lives, and alleviate the burden on limited health care resources.

Sex Differences in Influenza: The Challenge Study Experience.

BACKGROUND: Preclinical animal studies and retrospective human studies suggest that adult females have worse outcomes from influenza than males. Prospective studies in humans are missing. METHODS: Data from 164 healthy volunteers who underwent influenza A/California/04/2009/H1N1 challenge were compiled to compare differences between sexes. Baseline characteristics, including hormone levels, hemagglutination inhibition (HAI) titers, neuraminidase inhibition (NAI) titers, and outcomes after challenge were compared. Linear and logistic regression models were built to determine significant predictor variables with respect to outcomes of interest. RESULTS: HAI titers were similar between the sexes, but NAI titers were higher in males than females at 4 weeks and 8 weeks postchallenge. Females were more likely to have symptoms (mean, 0.96 vs 0.80; P = .003) and to have a higher number of symptoms (median, 3 vs 4; P = .011) than males. Linear and logistic regression models showed that prechallenge NAI titers, but not HAI titers or sex hormone levels, were predictive of all shedding and symptom outcomes of interest. CONCLUSIONS: Females in our cohorts were more likely to be symptomatic and to have a higher number of symptoms than males. NAI titers predicted all outcomes of interest and may explain differential outcomes between the sexes.

Gastric twist after sleeve gastrectomy: a proposal for endoscopic classification / Torção gástrica após gastrectomia vertical: uma proposta de classificação endoscópica

ABSTRACT - BACKGROUND: The twisting of the gastric tube is one of the main causes of persistent reflux and food intolerance after sleeve gastrectomy (SG). To date, there is no classification for gastric twist after SG. OBJECTIVE: This study aimed to propose an endoscopic classification for this condition and outline the clinical profile of these patients with sleeve gastrectomy. METHODS: Patients in the postoperative period of SG presenting endoscopic findings of gastric twist were included. All patients underwent an esophagogastroduodenoscopy 12 months after SG. The classification proposed consists of three degrees: degree I: mild rotation of the staple line without relevant shrinkage of the gastric lumen; degree II: moderate rotation of the staple line, leading to a focal area of fixed narrowing that requires additional maneuvers for its transposition; and degree III: severe rotation of the staple line leading to stenosis, with increased difficulty for transposition or complete blockage. RESULTS: Out of 2,723 patients who underwent SG, 45 (1.6%) presented gastric twist. Most patients were female (85%), with mean age of 39±10.4 years. In all, 41 (91.1%) presented degree I, 3 (6.7%) presented degree II, and 1 (2.2%) had degree III. Most patients were asymptomatic (n=26). Vomiting was the most prevalent symptom (15.5%). Statistically significant correlation of twisting degrees was not observed for both the presence of symptoms and the degrees of esophagitis. CONCLUSION: Gastric twist after SG is rare, with generally mild and asymptomatic presentation. The endoscopic classification was not statistically related to clinical presentation but set the ground for further analysis.

RESUMO - RACIONAL: A torção do tubo gástrico ou twist é uma das principais causas de refluxo persistente e intolerância alimentar após a gastrectomia vertical (GV). Até o momento, não há uma classificação proposta para a torção gástrica após GV. OBJETIVO: Propor uma classificação endoscópica para essa condição e descrever o perfil clínico desses pacientes. MÉTODOS: Pacientes no pós-operatório de GV apresentando achados endoscópicos de twist foram incluídos. Os pacientes foram submetidos a uma esofagogastroduodenoscopia 12 meses após a cirurgia. A classificação consiste em três graus. Grau I: rotação leve da linha de grampos, sem redução relevante do lúmen gástrico. Grau II: rotação moderada da linha de grampos, levando a uma área de estreitamento focal que requer manobras adicionais para a progressão do aparelho. Grau III: rotação severa da linha de grampos, levando à estenose, com grande dificuldade de progressão ou obstrução completa. RESULTADOS: Dos 2.723 pacientes que foram submetidos à GV, 45 (1,6%) apresentaram twist. A maioria dos pacientes era do sex feminino (85%), com idade média de 39±10.4 anos. Quarenta e um (91,1%) apresentaram twist grau I, 3 (6,7%) apresentaram twist grau II e apenas 1 (2,2%) apresentou twist grau III. A maioria dos pacientes eram assintomáticos (n=26). O sintoma mais prevalente foi vômito (15,5%). Não foi observada correlação estatisticamente significante entre o grau de twist e a presença de sintomas ou esofagite. CONCLUSÃO: Twist após GV é raro e geralmente assintomático. A classificação endoscópica proposta não foi estatisticamente relacionada com apresentação clínica, porém estabelece um referencial para análises futuras.

Undiagnosed SARS-CoV-2 seropositivity during the first 6 months of the COVID-19 pandemic in the United States.

Asymptomatic SARS-CoV-2 infection and delayed implementation of diagnostics have led to poorly defined viral prevalence rates in the United States and elsewhere. To address this, we analyzed seropositivity in 9089 adults in the United States who had not been diagnosed previously with COVID-19. Individuals with characteristics that reflected the U.S. population (n = 27,716) were selected by quota sampling from 462,949 volunteers. Enrolled participants (n = 11,382) provided medical, geographic, demographic, and socioeconomic information and dried blood samples. Survey questions coincident with the Behavioral Risk Factor Surveillance System survey, a large probability-based national survey, were used to adjust for selection bias. Most blood samples (88.7%) were collected between 10 May and 31 July 2020 and were processed using ELISA to measure seropositivity (IgG and IgM antibodies against SARS-CoV-2 spike protein and the spike protein receptor binding domain). The overall weighted undiagnosed seropositivity estimate was 4.6% (95% CI, 2.6 to 6.5%), with race, age, sex, ethnicity, and urban/rural subgroup estimates ranging from 1.1% to 14.2%. The highest seropositivity estimates were in African American participants; younger, female, and Hispanic participants; and residents of urban centers. These data indicate that there were 4.8 undiagnosed SARS-CoV-2 infections for every diagnosed case of COVID-19, and an estimated 16.8 million infections were undiagnosed by mid-July 2020 in the United States.

Heart Rate Variability and Clinical Features as Predictors of Atrial Fibrillation Recurrence After Catheter Ablation: A Pilot Study.

Single-procedure catheter ablation success rate is as low as 52% in atrial fibrillation (AF) patients. This study evaluated the feasibility of using clinical data and heart rate variability (HRV) features extracted from an implantable cardiac monitor (ICM) to predict recurrences in patients prior to undergoing catheter ablation for AF. HRV-derived features were extracted from the 500 beats preceding the AF onset and from the first 2 min of the last AF episode recorded by an ICM of 74 patients (67% male; 57 ± 12 years; 26% non-paroxysmal AF; 57% AF recurrence) before undergoing their first AF catheter ablation. Two types of classification algorithm were studied to predict AF recurrence: single classifiers including support vector machines, classification and regression trees, and K-nearest neighbor classifiers as well as ensemble classifiers. The sequential forward floating search algorithm was used to select the optimum feature set for each classification method. The optimum weighted voting method, which used an optimum combination of the single classifiers, was the best overall classifier (accuracy = 0.82, sensitivity = 0.76, and specificity = 0.87). Clinical and HRV features can be used to predict rhythm outcome using an ensemble classifier which would enable a more effective pre-ablation patient triage that could reduce the economic and personal burden of the procedure by increasing the success rate of first catheter ablation.

The effect of calcium and magnesium on activity, immunogenicity, and efficacy of a recombinant N1/N2 neuraminidase vaccine.

Despite the importance of immunity against neuraminidase (NA), NA content and immunogenicity are neglected in current influenza vaccines. To address this, a recombinant N1/N2 NA vaccine (NAV) was developed. Stability assays were used to determine optimal temperature and buffer conditions for vaccine storage. The effect of divalent cation-related enhancement of NA stability and activity on N1 and N2 immunogenicity and efficacy against viral challenge was assessed. Differences in activity between N1 and N2 and cation-related activity enhancement did not translate into differences in immunogenicity or efficacy. NAV-vaccinated mice showed robust antibody titers against N1 and N2, and after challenge with influenza A (H1N1) virus, decreased viral titers and decreased antiviral and inflammatory responses by transcriptomic analysis. These findings provide guidance for optimal storage and assessment of NA-based vaccines and confirm the importance of NA in influenza vaccination strategies in attenuating viral replication and limiting inflammatory responses necessary to clear infection.

Mapping a Pandemic: SARS-CoV-2 Seropositivity in the United States.

Asymptomatic SARS-CoV-2 infection and delayed implementation of diagnostics have led to poorly defined viral prevalence rates. To address this, we analyzed seropositivity in US adults who have not previously been diagnosed with COVID-19. Individuals with characteristics that reflect the US population (n = 11,382) and who had not previously been diagnosed with COVID-19 were selected by quota sampling from 241,424 volunteers (ClinicalTrials.gov NCT04334954). Enrolled participants provided medical, geographic, demographic, and socioeconomic information and 9,028 blood samples. The majority (88.7%) of samples were collected between May 10th and July 31st, 2020. Samples were analyzed via ELISA for anti-Spike and anti-RBD antibodies. Estimation of seroprevalence was performed by using a weighted analysis to reflect the US population. We detected an undiagnosed seropositivity rate of 4.6% (95% CI: 2.6 - 6.5%). There was distinct regional variability, with heightened seropositivity in locations of early outbreaks. Subgroup analysis demonstrated that the highest estimated undiagnosed seropositivity within groups was detected in younger participants (ages 18-45, 5.9%), females (5.5%), Black/African American (14.2%), Hispanic (6.1%), and Urban residents (5.3%), and lower undiagnosed seropositivity in those with chronic diseases. During the first wave of infection over the spring/summer of 2020 an estimate of 4.6% of adults had a prior undiagnosed SARS-CoV-2 infection. These data indicate that there were 4.8 (95% CI: 2.8-6.8) undiagnosed cases for every diagnosed case of COVID-19 during this same time period in the United States, and an estimated 16.8 million undiagnosed cases by mid-July 2020.

Mapping a Pandemic: SARS-CoV-2 Seropositivity in the United States

Asymptomatic SARS-CoV-2 infection and delayed implementation of diagnostics have led to poorly defined viral prevalence rates. To address this, we analyzed seropositivity in US adults who have not previously been diagnosed with COVID-19. Individuals with characteristics that reflect the US population (n = 11,382) and who had not previously been diagnosed with COVID-19 were selected by quota sampling from 241,424 volunteers (ClinicalTrials.gov NCT04334954). Enrolled participants provided medical, geographic, demographic, and socioeconomic information and 9,028 blood samples. The majority (88.7%) of samples were collected between May 10th and July 31st, 2020. Samples were analyzed via ELISA for anti-Spike and anti-RBD antibodies. Estimation of seroprevalence was performed by using a weighted analysis to reflect the US population. We detected an undiagnosed seropositivity rate of 4.6% (95% CI: 2.6 - 6.5%). There was distinct regional variability, with heightened seropositivity in locations of early outbreaks. Subgroup analysis demonstrated that the highest estimated undiagnosed seropositivity within groups was detected in younger participants (ages 18-45, 5.9%), females (5.5%), Black/African American (14.2%), Hispanic (6.1%), and Urban residents (5.3%), and lower undiagnosed seropositivity in those with chronic diseases. During the first wave of infection over the spring/summer of 2020 an estimate of 4.6% of adults had a prior undiagnosed SARS-CoV-2 infection. These data indicate that there were 4.8 (95% CI: 2.8-6.8) undiagnosed cases for every diagnosed case of COVID-19 during this same time period in the United States, and an estimated 16.8 million undiagnosed cases by mid-July 2020.