Survey of spiking in the mouse visual system reveals functional hierarchy.

The anatomy of the mammalian visual system, from the retina to the neocortex, is organized hierarchically1. However, direct observation of cellular-level functional interactions across this hierarchy is lacking due to the challenge of simultaneously recording activity across numerous regions. Here we describe a large, open dataset-part of the Allen Brain Observatory2-that surveys spiking from tens of thousands of units in six cortical and two thalamic regions in the brains of mice responding to a battery of visual stimuli. Using cross-correlation analysis, we reveal that the organization of inter-area functional connectivity during visual stimulation mirrors the anatomical hierarchy from the Allen Mouse Brain Connectivity Atlas3. We find that four classical hierarchical measures-response latency, receptive-field size, phase-locking to drifting gratings and response decay timescale-are all correlated with the hierarchy. Moreover, recordings obtained during a visual task reveal that the correlation between neural activity and behavioural choice also increases along the hierarchy. Our study provides a foundation for understanding coding and signal propagation across hierarchically organized cortical and thalamic visual areas.

Hierarchical organization of cortical and thalamic connectivity.

The mammalian cortex is a laminar structure containing many areas and cell types that are densely interconnected in complex ways, and for which generalizable principles of organization remain mostly unknown. Here we describe a major expansion of the Allen Mouse Brain Connectivity Atlas resource1, involving around a thousand new tracer experiments in the cortex and its main satellite structure, the thalamus. We used Cre driver lines (mice expressing Cre recombinase) to comprehensively and selectively label brain-wide connections by layer and class of projection neuron. Through observations of axon termination patterns, we have derived a set of generalized anatomical rules to describe corticocortical, thalamocortical and corticothalamic projections. We have built a model to assign connection patterns between areas as either feedforward or feedback, and generated testable predictions of hierarchical positions for individual cortical and thalamic areas and for cortical network modules. Our results show that cell-class-specific connections are organized in a shallow hierarchy within the mouse corticothalamic network.

Limited Sustained Remission After Nucleos(t)ide Analog Withdrawal: Results From a Large, Global, Multiethnic Cohort of Patients With Chronic Hepatitis B (RETRACT-B Study).

INTRODUCTION: Complete viral suppression with nucleos(t)ide analogs (NAs) has led to a profound reduction in hepatocellular carcinoma and mortality among patients with chronic hepatitis B. Finite therapy yields higher rates of functional cure; however, initial hepatitis B virus (HBV) DNA and alanine aminotransferase (ALT) elevations are almost certain after treatment interruption. We aimed to analyze off-treatment outcomes beyond 12 months after NA cessation. METHODS: Patients with well-suppressed chronic hepatitis B who were hepatitis B e antigen-negative at NA cessation and remained off treatment without hepatitis B surface antigen (HBsAg) loss at 12 months were included (n = 945). HBV DNA and ALT fluctuations were allowed within the first 12 months. We used Kaplan-Meier methods to analyze outcomes beyond 12 months. Sustained remission was defined as HBV DNA <2,000 IU/mL and ALT <2× upper limit of normal (ULN) and an ALT flare as ALT ≥5× ULN. RESULTS: Cumulative probability of sustained remission was 29.7%, virological relapse was 65.2% with a mean peak HBV DNA of 5.0 ± 1.5 log 10 IU/mL, an ALT flare was 15.6% with a median peak ALT × ULN of 8.3 (5.7-11.3), HBsAg loss was 9.9% and retreatment was 34.9% at 48 months after NA cessation. A single occurrence of virological relapse or an ALT flare within the first 12 months off-treatment were associated with significantly lower rates of sustained remission beyond 12 months. DISCUSSION: Despite allowing for HBV DNA and ALT fluctuations within the first 12 months off-treatment, most patients without HBsAg loss did not maintain a sustained response thereafter. The best candidates for NA withdrawal are patients with low HBsAg levels at NA cessation, and those without profound or recurrent virological and biochemical relapses in the first off-treatment year.

On the physiological and structural contributors to the overall balance of excitation and inhibition in local cortical networks.

Overall balance of excitation and inhibition in cortical networks is central to their functionality and normal operation. Such orchestrated co-evolution of excitation and inhibition is established through convoluted local interactions between neurons, which are organized by specific network connectivity structures and are dynamically controlled by modulating synaptic activities. Therefore, identifying how such structural and physiological factors contribute to establishment of overall balance of excitation and inhibition is crucial in understanding the homeostatic plasticity mechanisms that regulate the balance. We use biologically plausible mathematical models to extensively study the effects of multiple key factors on overall balance of a network. We characterize a network's baseline balanced state by certain functional properties, and demonstrate how variations in physiological and structural parameters of the network deviate this balance and, in particular, result in transitions in spontaneous activity of the network to high-amplitude slow oscillatory regimes. We show that deviations from the reference balanced state can be continuously quantified by measuring the ratio of mean excitatory to mean inhibitory synaptic conductances in the network. Our results suggest that the commonly observed ratio of the number of inhibitory to the number of excitatory neurons in local cortical networks is almost optimal for their stability and excitability. Moreover, the values of inhibitory synaptic decay time constants and density of inhibitory-to-inhibitory network connectivity are critical to overall balance and stability of cortical networks. However, network stability in our results is sufficiently robust against modulations of synaptic quantal conductances, as required by their role in learning and memory. Our study based on extensive bifurcation analyses thus reveal the functional optimality and criticality of structural and physiological parameters in establishing the baseline operating state of local cortical networks.

Association Between the Presence of Metabolic Comorbidities and Liver-Related Events in Patients With Chronic Hepatitis B.

BACKGROUND & AIMS: Patients with chronic hepatitis B (CHB) are at increased risk of hepatocellular carcinoma and (liver-related) mortality. In addition to hepatitis B-related factors, metabolic comorbidities may contribute to the progression of fibrosis. Therefore, we studied the association between metabolic comorbidities and adverse clinical outcomes in patients with CHB. METHODS: We conducted a retrospective cohort study of CHB patients attending the Erasmus MC University Medical Center (Rotterdam, The Netherlands) and CHB patients who underwent liver biopsy at the Toronto General Hospital (Toronto, Canada). The presence of metabolic comorbidities (ie, overweight, diabetes mellitus, hypertension, and dyslipidemia) was assessed based on chart review. The primary end point was liver-related events, defined as the first composite of hepatocellular carcinoma, liver transplantation, or liver-related mortality. RESULTS: We analyzed 1850 patients, of whom 926 (50.1%) were overweight, 161 (8.7%) had hypertension, 116 (6.3%) had dyslipidemia, and 82 (4.4%) had diabetes. During a median follow-up period of 7.3 years (interquartile range, 2.9-11.5 y), a total of 111 first events were recorded. Hypertension (hazard ratio [HR], 8.3; 95% CI, 5.5-12.7), diabetes (HR, 5.4; 95% CI, 3.2-9.1), dyslipidemia (HR, 2.8; 95% CI, 1.6-4.8), and overweight (HR, 1.7; 95% CI, 1.1-2.5) were associated with an increased risk for liver-related events. The presence of multiple comorbidities further increased the risk. Findings were consistent for patients with and without cirrhosis, among noncirrhotic hepatitis B e antigen-negative patients with hepatitis B virus DNA less than 2000 IU/mL and in multivariable analysis adjusting for age, sex, ethnicity, hepatitis B e antigen status, hepatitis B virus DNA, use of antiviral therapy, and the presence of cirrhosis. CONCLUSIONS: Metabolic comorbidities in CHB patients are associated with an increased risk for liver-related events, with the highest risk observed in patients with multiple comorbidities. Findings were consistent in various clinically relevant subgroups, underscoring the need for thorough metabolic assessment in patients with CHB.

Differential Relapse Patterns After Discontinuation of Entecavir vs Tenofovir Disoproxil Fumarate in Chronic Hepatitis B.

BACKGROUND AND AIMS: Whether entecavir (ETV) and tenofovir disoproxil fumarate (TDF) differentially affect relapse and outcomes following treatment discontinuation across different patient subpopulations remains unclear. We aimed to compare rates of off-therapy hepatitis B surface antigen (HBsAg) loss, virological and clinical relapse, and retreatment between chronic hepatitis B (CHB) patients who discontinued TDF or ETV therapy. METHODS: This study included 1402 virally suppressed CHB patients who stopped either ETV (n = 981) or TDF (n = 421) therapy between 2001 and 2020 from 13 participating centers across North America, Europe, and Asia. All patients were hepatitis B e antigen-negative at treatment discontinuation. Inverse probability of treatment weighting was used to balance the treatment groups. Outcomes were analyzed using survival methods. RESULTS: During a median off-treatment follow-up of 18 months, HBsAg loss occurred in 96 (6.8%) patients overall. Compared with ETV, TDF was associated with a higher rate of HBsAg loss (P = .03); however, the association was no longer significant after statistical adjustment (P = .61). Virological relapse occurred earlier among TDF-treated patients (P < .01); nonetheless, rates became comparable after the first year off therapy (P = .49). TDF was significantly associated with a higher clinical relapse rate than ETV throughout follow-up (P < .01). The development of a virological or clinical relapse did not affect the rate of HBsAg loss. Retreatment rates were not significantly different between the treatment groups. CONCLUSIONS: TDF and ETV have differential relapse patterns but are associated with similar rates of HBsAg loss and retreatment following discontinuation. Finite therapy can be considered for CHB patients on either TDF or ETV therapy.

Off-Therapy Response After Nucleos(t)ide Analogue Withdrawal in Patients With Chronic Hepatitis B: An International, Multicenter, Multiethnic Cohort (RETRACT-B Study).

BACKGROUND & AIMS: Functional cure, defined based on hepatitis B surface antigen (HBsAg) loss, is rare during nucleos(t)ide analogue (NA) therapy and guidelines on finite NA therapy have not been well established. We aim to analyze off-therapy outcomes after NA cessation in a large, international, multicenter, multiethnic cohort of patients with chronic hepatitis B (CHB). METHODS: This cohort study included patients with virally suppressed CHB who were hepatitis B e antigen (HBeAg)-negative and stopped NA therapy. Primary outcome was HBsAg loss after NA cessation, and secondary outcomes included virologic, biochemical, and clinical relapse, alanine aminotransferase flare, retreatment, and liver-related events after NA cessation. RESULTS: Among 1552 patients with CHB, cumulative probability of HBsAg loss was 3.2% at 12 months and 13.0% at 48 months of follow-up. HBsAg loss was higher among Whites (vs Asians: subdistribution hazard ratio, 6.8; 95% confidence interval, 2.7-16.8; P < .001) and among patients with HBsAg levels <100 IU/mL at end of therapy (vs ≥100 IU/mL: subdistribution hazard ratio, 22.5; 95% confidence interval, 13.1-38.7; P < .001). At 48 months of follow-up, Whites with HBsAg levels <1000 IU/mL and Asians with HBsAg levels <100 IU/mL at end of therapy had a high predicted probability of HBsAg loss (>30%). Incidence rate of hepatic decompensation and hepatocellular carcinoma was 0.48 per 1000 person-years and 0.29 per 1000 person-years, respectively. Death occurred in 7/19 decompensated patients and 2/14 patients with hepatocellular carcinoma. CONCLUSIONS: The best candidates for NA withdrawal are virally suppressed, HBeAg- negative, noncirrhotic patients with CHB with low HBsAg levels, particularly Whites with <1000 IU/mL and Asians with <100 IU/mL. However, strict surveillance is recommended to prevent deterioration.

Incidence of Hepatic Decompensation After Nucleos(t)ide Analog Withdrawal: Results From a Large, International, Multiethnic Cohort of Patients With Chronic Hepatitis B (RETRACT-B Study).

INTRODUCTION: Despite improvements in the management of chronic hepatitis B (CHB), risk of cirrhosis and hepatocellular carcinoma remains. While hepatitis B surface antigen loss is the optimal end point, safe discontinuation of nucleos(t)ide analog (NA) therapy is controversial because of the possibility of severe or fatal reactivation flares. METHODS: This is a multicenter cohort study of virally suppressed, end-of-therapy (EOT) hepatitis B e antigen (HBeAg)-negative CHB patients who stopped NA therapy (n = 1,557). Survival analysis techniques were used to analyze off-therapy rates of hepatic decompensation and differences by patient characteristics. We also examined a subgroup of noncirrhotic patients with consolidation therapy of ≥12 months before cessation (n = 1,289). Hepatic decompensation was considered related to therapy cessation if diagnosed off therapy or within 6 months of starting retreatment. RESULTS: Among the total cohort (11.8% diagnosed with cirrhosis, 84.2% start-of-therapy HBeAg-negative), 20 developed hepatic decompensation after NA cessation; 10 events were among the subgroup. The cumulative incidence of hepatic decompensation at 60 months off therapy among the total cohort and subgroup was 1.8% and 1.1%, respectively. The hepatic decompensation rate was higher among patients with cirrhosis (hazard ratio [HR] 5.08, P < 0.001) and start-of-therapy HBeAg-positive patients (HR 5.23, P < 0.001). This association between start-of-therapy HBeAg status and hepatic decompensation remained significant even among the subgroup (HR 10.5, P < 0.001). DISCUSSION: Patients with cirrhosis and start-of-therapy HBeAg-positive patients should be carefully assessed before stopping NAs to prevent hepatic decompensation. Frequent monitoring of viral and host kinetics after cessation is crucial to determine patient outcome.

Getting to HBV cure: The promising paths forward.

Chronic HBV infection is a global public health burden estimated to impact nearly 300 million persons worldwide. Despite the advent of potent antiviral agents that effectively suppress viral replication, HBV cure remains difficult to achieve because of the persistence of covalently closed circular DNA (cccDNA), HBV-DNA integration into the host genome, and impaired immune response. Indefinite treatment is necessary for most patients to maintain level of viral suppression. The success of direct-acting antivirals (DAAs) for hepatitis C treatment has rejuvenated the search for a cure for chronic hepatitis B (CHB), though an HBV cure likely requires an additional layer: immunomodulators for restoration of robust immune responses. DAAs such as entry inhibitors, capsid assembly modulators, inhibitors of subviral particle release, cccDNA silencers, and RNA interference molecules have reached clinical development. Immunomodulators, namely innate immunomodulators (Toll-like receptor agonists), therapeutic vaccines, checkpoint inhibitors, and monoclonal antibodies, are also progressing toward clinical development. The future of the HBV cure possibly lies in triple combination therapies with concerted action on replication inhibition, antigen reduction, and immune stimulation. Many obstacles remain, such as overcoming translational failures, choosing the right endpoint using the right biomarkers, and leveraging current treatments in combination regimens to enhance response rates. This review gives an overview of the current therapies for CHB, HBV biomarkers used to evaluate treatment response, and development of DAAs and immune-targeting drugs and discusses the limitations and unanswered questions on the journey to an HBV cure.

Exploring the experiences of frontline nurses caring for COVID-19 patients.

AIM: This study seeks to gain a comprehensive understanding of the experiences of frontline nurses who provided direct care for COVID-19 patients. BACKGROUND: Due to the COVID-19 pandemic, the demands on healthcare systems have been higher than before. Although previous studies have explored the experiences of frontline nurses, these experiences could vary depending on each country's social, cultural, and historical contexts. INTRODUCTION: In the midst of the global pandemic, sharing the experiences of COVID-19 frontline nurses could have implications for both nursing and nursing policies that could be applied to future pandemics. METHODS: This descriptive qualitative study comprised 14 South Korean nurses with a minimum of one month of experience working within a COVID-19 department. Individual interviews were conducted on a virtual platform, and a thematic analysis was employed. The consolidated criteria for reporting qualitative studies were used to ensure a detailed reporting of the study. RESULTS: Four themes and 12 subthemes were developed. The themes included: (1) feeling forced into a world of uncertainty; (2) providing unique care for COVID-19 patients; (3) perceiving barriers to providing quality care; and (4) seeking meaning in caring for COVID-19 patients. DISCUSSION: Nurses recognized their unique roles in caring for COVID-19 patients and sought new meanings within their profession. However, the poor work environment exacerbated the physical and emotional burden among the nurses and compromised the provision of quality care. CONCLUSION: This study highlighted the nursing policy issues that need to be improved to ensure better quality care and a stronger healthcare system. IMPLICATIONS FOR NURSING POLICY: Governmental action is essential to ensure that nurses can maintain the quality of care they have provided during COVID-19 and any future pandemics.

Engineered receptors for human cytomegalovirus that are orthogonal to normal human biology.

A trimeric glycoprotein complex on the surface of human cytomegalovirus (HCMV) binds to platelet-derived growth factor (PDGF) receptor α (PDGFRα) to mediate host cell recognition and fusion of the viral and cellular membranes. Soluble PDGFRα potently neutralizes HCMV in tissue culture, and its potential use as an antiviral therapeutic has the benefit that any escape mutants will likely be attenuated. However, PDGFRα binds multiple PDGF ligands in the human body as part of developmental programs in embryogenesis and continuing through adulthood. Any therapies with soluble receptor therefore come with serious efficacy and safety concerns, especially for the treatment of congenital HCMV. Soluble virus receptors that are orthogonal to human biology might resolve these concerns. This engineering problem is solved by deep mutational scanning on the D2-D3 domains of PDGFRα to identify variants that maintain interactions with the HCMV glycoprotein trimer in the presence of competing PDGF ligands. Competition by PDGFs is conformation-dependent, whereas HCMV trimer binding is independent of proper D2-D3 conformation, and many mutations at the receptor-PDGF interface are suitable for functionally separating trimer from PDGF interactions. Purified soluble PDGFRα carrying a targeted mutation succeeded in displaying wild type affinity for HCMV trimer with a simultaneous loss of PDGF binding, and neutralizes trimer-only and trimer/pentamer-expressing HCMV strains infecting fibroblasts or epithelial cells. Overall, this work makes important progress in the realization of soluble HCMV receptors for clinical application.

Molecular determinants of chaperone interactions on MHC-I for folding and antigen repertoire selection.

The interplay between a highly polymorphic set of MHC-I alleles and molecular chaperones shapes the repertoire of peptide antigens displayed on the cell surface for T cell surveillance. Here, we demonstrate that the molecular chaperone TAP-binding protein related (TAPBPR) associates with a broad range of partially folded MHC-I species inside the cell. Bimolecular fluorescence complementation and deep mutational scanning reveal that TAPBPR recognition is polarized toward the α2 domain of the peptide-binding groove, and depends on the formation of a conserved MHC-I disulfide epitope in the α2 domain. Conversely, thermodynamic measurements of TAPBPR binding for a representative set of properly conformed, peptide-loaded molecules suggest a narrower MHC-I specificity range. Using solution NMR, we find that the extent of dynamics at "hotspot" surfaces confers TAPBPR recognition of a sparsely populated MHC-I state attained through a global conformational change. Consistently, restriction of MHC-I groove plasticity through the introduction of a disulfide bond between the α1/α2 helices abrogates TAPBPR binding, both in solution and on a cellular membrane, while intracellular binding is tolerant of many destabilizing MHC-I substitutions. Our data support parallel TAPBPR functions of 1) chaperoning unstable MHC-I molecules with broad allele-specificity at early stages of their folding process, and 2) editing the peptide cargo of properly conformed MHC-I molecules en route to the surface, which demonstrates a narrower specificity. Our results suggest that TAPBPR exploits localized structural adaptations, both near and distant to the peptide-binding groove, to selectively recognize discrete conformational states sampled by MHC-I alleles, toward editing the repertoire of displayed antigens.

Longitudinal Assessment of Diagnostic Test Performance Over the Course of Acute SARS-CoV-2 Infection.

BACKGROUND: Serial screening is critical for restricting spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by facilitating timely identification of infected individuals to interrupt transmission. Variation in sensitivity of different diagnostic tests at different stages of infection has not been well documented. METHODS: In a longitudinal study of 43 adults newly infected with SARS-CoV-2, all provided daily saliva and nasal swabs for quantitative reverse transcription polymerase chain reaction (RT-qPCR), Quidel SARS Sofia antigen fluorescent immunoassay (FIA), and live virus culture. RESULTS: Both RT-qPCR and Quidel SARS Sofia antigen FIA peaked in sensitivity during the period in which live virus was detected in nasal swabs, but sensitivity of RT-qPCR tests rose more rapidly prior to this period. We also found that serial testing multiple times per week increases the sensitivity of antigen tests. CONCLUSIONS: RT-qPCR tests are more effective than antigen tests at identifying infected individuals prior to or early during the infectious period and thus for minimizing forward transmission (given timely results reporting). All tests showed >98% sensitivity for identifying infected individuals if used at least every 3 days. Daily screening using antigen tests can achieve approximately 90% sensitivity for identifying infected individuals while they are viral culture positive.

Association Between Seroclearance of Hepatitis B Surface Antigen and Long-term Clinical Outcomes of Patients With Chronic Hepatitis B Virus Infection: Systematic Review and Meta-analysis.

BACKGROUND & AIMS: Seroclearance of hepatitis B surface antigen (HBsAg) is the desired end point of treatment for chronic hepatitis B virus (HBV) infection, according to guidelines. We performed a systematic review and meta-analysis to evaluate the strength of the association between HBsAg seroclearance and long-term clinical outcomes. METHODS: We performed a systematic review of the PubMed, EMBASE, and Cochrane Library databases for articles that assessed HBsAg status and reported the incidence of hepatocellular carcinoma (HCC), liver decompensation, liver transplantation, and/or all-cause mortality during follow-up evaluation. We performed a meta-analysis of rate ratios (RR) using a random-effects model independently for each end point and for a composite end point. RESULTS: We analyzed data from 28 studies, comprising a total of 188,316 patients with chronic HBV infection (treated and untreated), and 1,486,081 person-years (PY) of follow-up evaluation; 26 reported data on HCC, 7 on liver decompensation, and 13 on liver transplantation and/or death. The composite event rates were 0.19/1000 PY for the HBsAg seroclearance group and 2.45/1000 PY for the HBsAg-persistent group. Pooled RRs for the HBsAg seroclearance group were 0.28 for liver decompensation (95% CI, 0.13-0.59; P = .001), 0.30 for HCC (95% CI, 0.20-0.44; P < .001), 0.22 for liver transplantation and/or death (95% CI, 0.13-0.39; P < .001), and 0.31 for the composite end point (95% CI, 0.23-0.43; P < .001). No differences in RR estimates were observed among subgroups of different study or patient characteristics. CONCLUSIONS: In a systematic review and meta-analysis, we found seroclearance of HBsAg to be associated significantly with improved patient outcomes. The results are consistent among different types of studies, in all patient subpopulations examined, and support the use of HBsAg seroclearance as a primary end point of trials of patients with chronic HBV infection.

Ultra-Long-term Follow-up of Interferon Alfa Treatment for HBeAg-Positive Chronic Hepatitis B Virus Infection.

BACKGROUND AND AIMS: Interferon-alpha (IFN-α) treatment for chronic hepatitis B (CHB) virus infection is finite and leads to relatively higher functional cure rates (HBsAg loss) than nucleo(s)tide analogue (NA) therapy. Effects of pegylated (PEG)/conventional IFN-α treatment on clinical outcomes were evaluated in an ultra-long-term follow-up of CHB patients. METHODS: HBeAg-positive patients treated with (PEG)IFN-α at a tertiary referral centre between 1977-2014 were included. We reviewed medical charts and consulted the municipal registry for patient information. Patients were invited for a single visit at the outpatient clinic in the case of missing follow-up data. The endpoints included serum HBeAg/HBsAg loss and incidence of clinical events, using life table methods and person-years to analyze the incidence of events. Patients were censored upon retreatment. RESULTS: The study cohort included 267 patients, 67% male, 58% Caucasian, with a median age of 32 years. The median follow-up duration was 11.5 years. The 5 and 10-year cumulative incidence of HBsAg loss were 14% and 32%, respectively. Baseline factors associated with a higher rate of HBsAg loss were male sex, Caucasian race, genotype A, age ≥40 years, and cirrhosis. HBsAg loss rates did not differ significantly between those who received short-term (≤24 weeks) vs long-term (>24 weeks) therapy. Both HBeAg and HBsAg loss were significantly associated with improved clinical outcomes. Early response (HBeAg loss) was associated with more HBsAg loss and better patient outcomes. CONCLUSIONS: During long-term follow-up, high rates of HBsAg loss were observed from a single (PEG)IFN-α course. Its persistent effects suggest that a role for IFN-α remains, potentially in novel combination therapies in search of a functional cure.

Effects of on-treatment ALT flares on serum HBsAg and HBV RNA in patients with chronic HBV infection.

As pegylated interferon alpha (PEG-IFN-α) is increasingly used in combination regimens of novel drugs, we aimed to characterize ALT flares and their relationship with serum HBsAg and HBV RNA kinetics in a large combined cohort of chronic hepatitis B (CHB) patients on PEG-IFN-α-based therapy. In this post hoc analysis of four international randomized trials, 269/130/124/128 patients on PEG-IFN-α monotherapy, PEG-IFN-α plus nucleos(t)ide analogue (NA) de novo combination, PEG-IFN-α add-on to NA or NA monotherapy were included, respectively. A flare was defined as an episode of ALT ≥5 × ULN. The association between flares and HBsAg and HBV RNA changes were examined. On-treatment flares occurred in 83/651 (13%) patients (median timing/magnitude: week 8 [IQR 4-12], 7.6 × ULN [IQR 6.2-10.5]). Flare patients were more often Caucasians with genotype A/D and had higher baseline ALT, HBV DNA, HBV RNA and HBsAg levels than the no-flare group. More flares were observed on PEG-IFN-α monotherapy (18%) and PEG-IFN+NA de novo combination (24%) vs. PEG-IFN-α add-on (2%) or NA monotherapy (1%) (p < .001). On-treatment flares were significantly and independently associated with HBsAg and HBV RNA decline ≥1 log10 at the final visit declines started shortly before the flare, progressing towards 24 weeks thereafter. On-treatment flares were seen in 16/22 (73%) patients who achieved HBsAg loss. In conclusion, ALT flares during PEG-IFN-α treatment are associated with subsequent HBsAg and HBV RNA decline and predict subsequent HBsAg loss. Flares rarely occurred during PEG-IFN-α add-on therapy and associated with low HBsAg loss rates. Combination regimens targeting the window of heightened response could be promising.

Nonalcoholic Steatohepatitis Is Associated With Liver-Related Outcomes and All-Cause Mortality in Chronic Hepatitis B.

BACKGROUND AND AIMS: Chronic hepatitis B (CHB) and nonalcoholic fatty liver disease are increasingly observed together in clinical practice, and development of nonalcoholic steatohepatitis (NASH) represents another leading cause of liver-related morbidity and mortality. Our aims were to determine whether biopsy-proven NASH impacts clinical outcomes in CHB patients and assess prognostic risk factors. APPROACH AND RESULTS: CHB patients attending two tertiary centers in North America and Europe over 13 years with available clinical and biopsy data were included. Patients were categorized as no-NASH or probable/definite NASH based on standardized histological assessment. Clinical events (death, decompensation, transplant, and hepatoma) were evaluated, and Kaplan-Meier survival estimates and Cox proportional hazards regression were used to analyze the incidence of events. There were 1,089 CHB patients, classified as no-NASH (n = 904, 83%) or NASH (n = 185, 17%), with 52 (6%) versus 27 (15%) experiencing outcome events during follow-up, respectively. In the multivariable analysis adjusting for age, sex, hepatitis B e antigen serostatus, and diabetes, the presence of NASH and concomitant advanced fibrosis (AF) was significantly associated with clinical outcomes (hazard ratio [95% confidence interval], 4.8 [2.6-9.0], P < 0.01) when compared to absence of NASH and AF (reference). NASH and AF were associated with a greater risk of outcomes compared to AF (P = 0.01) or NASH alone (P < 0.01). Of the three histological determinants of NASH, ballooning and inflammation, but not steatosis, were independently associated with clinical outcomes (P < 0.05) in place of NASH. NASH was significantly associated with increased risk of hepatocellular carcinoma and death (P < 0.01) but not decompensation (P = 0.33). CONCLUSIONS: In our large combined tertiary center cohort, patients with concomitant NASH and CHB had more AF and shorter time to development of liver-related outcomes or death compared to patients with CHB alone. Among patients with AF, superimposed NASH predicted poorer clinical outcomes.

Conformational Engineering of HIV-1 Env Based on Mutational Tolerance in the CD4 and PG16 Bound States.

HIV-1 infection is initiated by viral Env engaging the host receptor CD4, triggering Env to transition from a "closed" to "open" conformation during the early events of virus-cell membrane fusion. To understand how Env sequence accommodates this conformational change, mutational landscapes decoupled from virus replication were determined for Env from BaL (clade B) and DU422 (clade C) isolates interacting with CD4 or antibody PG16 that preferentially recognizes closed trimers. Sequence features uniquely important to each bound state were identified, including glycosylation and binding sites. Notably, the Env apical domain and trimerization interface are under selective pressure for PG16 binding. Based on this key observation, mutations were found that increase presentation of quaternary epitopes associated with properly conformed trimers when Env is expressed at the plasma membrane. Many mutations reduce electrostatic repulsion at the Env apex and increase PG16 recognition of Env sequences from clades A and B. Other mutations increase hydrophobic packing at the gp120 inner-outer domain interface and were broadly applicable for engineering Env from diverse strains spanning tiers 1, 2, and 3 across clades A, B, C, and BC recombinants. Core mutations predicted to introduce steric strain in the open state show markedly reduced CD4 interactions. Finally, we demonstrate how our methodology can be adapted to interrogate interactions between membrane-associated Env and the matrix domain of Gag. These findings and methods may assist vaccine design.IMPORTANCE HIV-1 Env is dynamic and undergoes large conformational changes that drive fusion of virus and host cell membranes. Three Env proteins in a trimer contact each other at their apical tips to form a closed conformation that presents epitopes recognized by broadly neutralizing antibodies. The apical tips separate, among other changes, to form an open conformation that binds tightly to host receptors. Understanding how Env sequence facilitates these structural changes can inform the biophysical mechanism and aid immunogen design. Using deep mutational scans decoupled from virus replication, we report mutational landscapes for Env from two strains interacting with conformation-dependent binding proteins. Residues in the Env trimer interface and apical domains are preferentially conserved in the closed conformation, and conformational diversity is facilitated by electrostatic repulsion and an underpacked core between domains. Specific mutations are described that enhance presentation of the trimeric closed conformation across diverse HIV-1 strains.

Has Breast Surgery Shattered the Glass Ceiling? Trends in Female Representation at The American Society of Breast Surgeons Annual Meeting 2009-2019.

BACKGROUND: Our study sought to evaluate gender representation and the impact of gender on the large volume of research presented at The American Society of Breast Surgeons (ASBrS) Annual Meeting, the largest breast surgery meeting in the United States. METHODS: Publicly available ASBrS meeting programs and proceedings from 2009 to 2019 were reviewed to ascertain proportions of female engagement in society positions, contributions to scientific sessions, and subsequent manuscript publications. Trend analyses for temporal changes in gender representation and univariate tests of associations between authorship gender and publication success were performed. RESULTS: Women comprised 44.8% of members of the board of directors, 41.7% of committee chairs, and 54.8% of committee members. There were significant annual increased proportions of female committee members (3.2% per year, p = 0.01) and chairs (6.0% per year, p = 0.03). Women represented > 50% of all speakership positions, except keynote (42.2%). For oral, quickshot, and poster scientific presentations, > 70% of first authors and > 60% of senior authors were women. The meeting-related publication rate with female senior authorship was higher than that with male senior authorship (41.0% vs. 36.3%, p = 0.04). CONCLUSIONS: Although female surgeons remain a minority at most conferences, women have represented the majority of participants in committees, speakership, and scientific presentations at the ASBrS Annual Meeting over the past 10 years. The glass ceiling in breast surgery has been shattered, but efforts to improve gender equity must continue, not only in breast surgery, but all surgical specialties.

Synchronization dependent on spatial structures of a mesoscopic whole-brain network.

Complex structural connectivity of the mammalian brain is believed to underlie the versatility of neural computations. Many previous studies have investigated properties of small subsystems or coarse connectivity among large brain regions that are often binarized and lack spatial information. Yet little is known about spatial embedding of the detailed whole-brain connectivity and its functional implications. We focus on closing this gap by analyzing how spatially-constrained neural connectivity shapes synchronization of the brain dynamics based on a system of coupled phase oscillators on a mammalian whole-brain network at the mesoscopic level. This was made possible by the recent development of the Allen Mouse Brain Connectivity Atlas constructed from viral tracing experiments together with a new mapping algorithm. We investigated whether the network can be compactly represented based on the spatial dependence of the network topology. We found that the connectivity has a significant spatial dependence, with spatially close brain regions strongly connected and distal regions weakly connected, following a power law. However, there are a number of residuals above the power-law fit, indicating connections between brain regions that are stronger than predicted by the power-law relationship. By measuring the sensitivity of the network order parameter, we show how these strong connections dispersed across multiple spatial scales of the network promote rapid transitions between partial synchronization and more global synchronization as the global coupling coefficient changes. We further demonstrate the significance of the locations of the residual connections, suggesting a possible link between the network complexity and the brain's exceptional ability to swiftly switch computational states depending on stimulus and behavioral context.