A Unique Presentation of Acute Biliary Ascites Due to Spontaneous Biliary Duct Perforation With Bowel Obstruction: A Case Report.

Biliary ascites due to spontaneous biliary duct perforation is a rare case presentation usually seen in the paediatric age group of 6-36 months. We are presenting the case of a 14-month-old baby with abdominal distention associated with abdominal pain, vomiting, fever, and a history of no passage of stools. Upon examination, the abdomen was tense and tender. On radiological investigations, gross free fluid was present in the abdominal cavity along with bowel obstruction and partial situs inversus of the spleen and stomach. The bowel obstruction was relieved by rectal stimulation, after which oral feeds were well tolerated. Bilious fluid was found on diagnostic paracentesis, confirming the diagnosis. The patient was managed further by broad-spectrum antibiotics and drainage of the free fluid. The management ranges from conservative treatment to Roux-en-Y anastomosis. A non-surgical diagnosis is uncommonly seen and helps improve the patient's prognosis if detected early. This case report highlights the importance of early diagnosis and non-surgical treatment modality in critical patients.

Visual Cortical Thickness Increases with Prolonged Artificial Vision Restoration.

The Argus II retinal prosthesis restores visual perception to late blind patients. It has been shown that structural changes occur in the brain due to late-onset blindness, including cortical thinning in visual regions of the brain. Following vision restoration, it is not yet known whether these visual regions are reinvigorated and regain a normal cortical thickness or retain the diminished thickness from blindness. We evaluated the cortical thicknesses of ten Argus II Retinal Prostheses patients, ten blind patients, and thirteen sighted participants. The Argus II patients on average had a thicker left Cuneus Cortex and Lateral Occipital Cortex relative to the blind patients. The duration of the Argus II use (time since implant in active users) significantly partially correlated with thicker visual cortical regions in the left hemisphere. Furthermore, in the two case studies (scanned before and after implantation), the patient with longer device use (44.5 months) had an increase in the cortical thickness of visual regions, whereas the shorter-using patient did not (6.5 months). Finally, a third case, scanned at three time points post-implantation, showed an increase in cortical thickness in the Lateral Occipital Cortex between 43.5 and 57 months, which was maintained even after 3 years of disuse (106 months). Overall, the Argus II patients' cortical thickness was on average significantly rejuvenated in two higher visual regions and, patients using the implant for a longer duration had thicker visual regions. This research raises the possibility of structural plasticity reversing visual cortical atrophy in late-blind patients with prolonged vision restoration.

Fertility and pregnancy outcomes in primary hyperparathyroidism: Observations from a large insured population.

CONTEXT: Primary hyperparathyroidism (PHPT) has initially been implicated in adverse maternal and neonatal outcomes, while subsequent population studies have failed to show an association. OBJECTIVE: To compare maternal, pregnancy, and neonatal outcomes in patients with and without PHPT. DESIGN: Retrospective matched-cohort study (2005-2020). SETTING: An integrated healthcare delivery system in Southern California. PATIENTS: Women aged 18-44 years were included. Patients with biochemical diagnosis of PHPT were matched 1:3 with eucalcemic controls (non-PHPT). MAIN OUTCOME MEASURES: Achievement of pregnancy, pregnancy outcomes (including rates of abortion, maternal complications), and neonatal outcomes (including hypocalcemia, need for intensive care). RESULTS: The cohort comprised 386 women with PHPT and 1158 age-matched controls. Pregnancy rates between PHPT and control groups were similar (10.6% vs 12.8%). The adjusted rate ratio of pregnancy was 0.89 (95% CI: 0.64-1.24) (PHPT vs non-PHPT). Twenty-nine pregnancies occurred in women with co-existing PHPT and 191 pregnancies occurred in controls, resulting in 23 (79.3%) and 168 (88.0%) live births, respectively (p=0.023). Neonatal outcomes were similar. Live birth rates were similar (86.4%, 80%, 79.2%) for those undergoing parathyroidectomy prior (n=22), during (n=5), or after pregnancy/never (n=24). Among patients who underwent parathyroidectomy during pregnancy, no spontaneous abortions occurred in women entering pregnancy with peak calcium <11.5 mg/dL [2.9 mmol/L]. CONCLUSIONS: We observed no difference in pregnancy rates between women with or without PHPT. Performing parathyroidectomy before pregnancy or during the second trimester appears to be a safe and successful strategy, and adherence to this strategy may be most critical for patients with higher calcium levels (≥11.5 mg/dL [2.9 mmol/L]).

Postoperative pain control and opioid use with transversus abdominis plane block and scheduled multimodal pain management in patients undergoing cesarean section.

OBJECTIVE: The impact of a transversus abdominis plane (TAP) block in patients undergoing cesarean section requires further evaluation. The aim of this study was to compare postoperative pain scores and opioid use in cesarean surgery patients undergoing either a TAP block and scheduled multimodal pain management (SMPM) or SMPM alone. METHODS: In this retrospective, dual cohort study, cesarean surgery patients underwent neuraxial anesthesia and a TAP block (SMPM/TAP) or SMPM; the TAP block incorporated ropivacaine (20-30 mL) administered bilaterally. The group analyses involved a comparison of postoperative pain scores using the visual analog scale and opioid consumption at 24 and 24-48 h. RESULTS: There were 94 (52.8%) patients in the SMPM/TAP group and 84 (47.2%) subjects in the SMPM alone group. At 24 h postoperatively, the SMPM/TAP group exhibited significantly lower pain scores (4.07 vs 4.54) than the SMPM group (P < 0.001) and reduced opioid consumption (2.29 vs 3.28 mg; P < 0.001). However, at 24-48 h, the SMPM group demonstrated lower pain scores (5.46 vs 5.98) compared to the SMPM/TAP group (P < 0.001) and reduced opioid consumption (8.75 vs 10.21 mg; P < 0.001); overall opioid consumption was higher (12.50 vs 12.02 mg) in the SMPM/TAP group (P < 0.001). CONCLUSION: The TAP block improved cesarean surgery patients' pain scores and reduced opioid consumption at 24 h postoperatively but the effect of the TAP block was ephemeral as the SMPM/TAP group exhibited inferior pain scores and greater opioid consumption compared to the SMPM group at 24-48 h postoperatively.

A Review on the Use of Artificial Intelligence in Fracture Detection.

Artificial intelligence (AI) simulates intelligent behavior using computers with minimum human intervention. Recent advances in AI, especially deep learning, have made significant progress in perceptual operations, enabling computers to convey and comprehend complicated input more accurately. Worldwide, fractures affect people of all ages and in all regions of the planet. One of the most prevalent causes of inaccurate diagnosis and medical lawsuits is overlooked fractures on radiographs taken in the emergency room, which can range from 2% to 9%. The workforce will soon be under a great deal of strain due to the growing demand for fracture detection on multiple imaging modalities. A dearth of radiologists worsens this rise in demand as a result of a delay in hiring and a significant percentage of radiologists close to retirement. Additionally, the process of interpreting diagnostic images can sometimes be challenging and tedious. Integrating orthopedic radio-diagnosis with AI presents a promising solution to these problems. There has recently been a noticeable rise in the application of deep learning techniques, namely convolutional neural networks (CNNs), in medical imaging. In the field of orthopedic trauma, CNNs are being documented to operate at the proficiency of expert orthopedic surgeons and radiologists in the identification and categorization of fractures. CNNs can analyze vast amounts of data at a rate that surpasses that of human observations. In this review, we discuss the use of deep learning methods in fracture detection and classification, the integration of AI with various imaging modalities, and the benefits and disadvantages of integrating AI with radio-diagnostics.

From Bench-to-Bedside: How Artificial Intelligence is Changing Thyroid Nodule Diagnostics, a Systematic Review.

CONTEXT: Use of artificial intelligence (AI) to predict clinical outcomes in thyroid nodule diagnostics has grown exponentially over the past decade. The greatest challenge is in understanding the best model to apply to one's own patient population, and how to operationalize such a model in practice. EVIDENCE ACQUISITION: A literature search of PubMed and IEEE Xplore was conducted for English-language publications between January 1, 2015 and January 1, 2023, studying diagnostic tests on suspected thyroid nodules that used AI. We excluded articles without prospective or external validation, nonprimary literature, duplicates, focused on nonnodular thyroid conditions, not using AI, and those incidentally using AI in support of an experimental diagnostic outside standard clinical practice. Quality was graded by Oxford level of evidence. EVIDENCE SYNTHESIS: A total of 61 studies were identified; all performed external validation, 16 studies were prospective, and 33 compared a model to physician prediction of ground truth. Statistical validation was reported in 50 papers. A diagnostic pipeline was abstracted, yielding 5 high-level outcomes: (1) nodule localization, (2) ultrasound (US) risk score, (3) molecular status, (4) malignancy, and (5) long-term prognosis. Seven prospective studies validated a single commercial AI; strengths included automating nodule feature assessment from US and assisting the physician in predicting malignancy risk, while weaknesses included automated margin prediction and interobserver variability. CONCLUSION: Models predominantly used US images to predict malignancy. Of 4 Food and Drug Administration-approved products, only S-Detect was extensively validated. Implementing an AI model locally requires data sanitization and revalidation to ensure appropriate clinical performance.

Exploration biases forelimb reaching strategies.

The brain can generate actions, such as reaching to a target, using different movement strategies. We investigate how such strategies are learned in a task where perched head-fixed mice learn to reach to an invisible target area from a set start position using a joystick. This can be achieved by learning to move in a specific direction or to a specific endpoint location. As mice learn to reach the target, they refine their variable joystick trajectories into controlled reaches, which depend on the sensorimotor cortex. We show that individual mice learned strategies biased to either direction- or endpoint-based movements. This endpoint/direction bias correlates with spatial directional variability with which the workspace was explored during training. Model-free reinforcement learning agents can generate both strategies with similar correlation between variability during training and learning bias. These results provide evidence that reinforcement of individual exploratory behavior during training biases the reaching strategies that mice learn.

GPR161 structure uncovers the redundant role of sterol-regulated ciliary cAMP signaling in the Hedgehog pathway.

The orphan G protein-coupled receptor (GPCR) GPR161 plays a central role in development by suppressing Hedgehog signaling. The fundamental basis of how GPR161 is activated remains unclear. Here, we determined a cryogenic-electron microscopy structure of active human GPR161 bound to heterotrimeric Gs. This structure revealed an extracellular loop 2 that occupies the canonical GPCR orthosteric ligand pocket. Furthermore, a sterol that binds adjacent to transmembrane helices 6 and 7 stabilizes a GPR161 conformation required for Gs coupling. Mutations that prevent sterol binding to GPR161 suppress Gs-mediated signaling. These mutants retain the ability to suppress GLI2 transcription factor accumulation in primary cilia, a key function of ciliary GPR161. By contrast, a protein kinase A-binding site in the GPR161 C terminus is critical in suppressing GLI2 ciliary accumulation. Our work highlights how structural features of GPR161 interface with the Hedgehog pathway and sets a foundation to understand the role of GPR161 function in other signaling pathways.

Diagnostic performance of molecular testing in indeterminate (Bethesda III and IV) thyroid nodules with Hürthle cell cytology.

BACKGROUND: Indeterminate thyroid nodules with Hürthle cell cytology remain a diagnostic challenge. The low benign call rate and positive predictive value of first-generation molecular tests precluded their use to rule out malignancy. We examined the diagnostic performance of current tests. METHOD: This subset analysis of our prospective randomized trial compared the benign call rate and positive predictive value of Afirma Gene Sequencing Classifier and Thyroseq v3 in Bethesda III and IV nodules with Hürthle cell cytology. Molecular test samples were obtained at initial fine-needle aspiration (8/2017-7/2022) and reflexively sent for processing. RESULTS: Molecular testing was performed on 140 Hürthle cell nodules. Of 79 nodules tested with the Afirma Gene Sequencing Classifier, the benign call rate was 84% (66/79). Nine of 66 nodules with benign results were resected, with no malignancies. Twelve of 13 nodules with suspicious results were resected, revealing 3 malignancies-2 papillary thyroid carcinomas and one Hürthle cell carcinoma (positive predictive value 25%). Of 61 nodules tested with Thyroseq v3, the benign call rate was 56% (34/61; (P < .01 versus Afirma Gene Sequencing Classifier). Five of 34 nodules with negative results were resected, with no malignancies. Nineteen of 27 nodules with positive results were resected, revealing 3 malignancies-2 papillary thyroid carcinomas and 1 Hürthle cell carcinoma (positive predictive value 16%). CONCLUSION: The high benign call rate of current molecular tests in Hürthle cell nodules strengthens their value in enabling patients to avoid surgery.

Applications of Latissimus Dorsi Grafts in Reverse Shoulder Arthroplasty.

The shoulder joint is a multiaxial joint in the upper body known for its high degree of motion. It is also infamously known for recurrent dislocations compared to other joints. These dislocations are mainly fixed by closed reduction methods like the Hippocrates technique, Stimpson's gravity technique, and the most commonly used modified Kocher's technique. The modified Kocher's technique uses traction followed by external rotation, adduction, and internal rotation. Rotator cuff tears are associated with shoulder joint dislocations. Rotator cuff tears slowly heal and persist for 10-20 years, irrespective of their etiology. When left untreated, fibrosis can set in the joint. After fibrosis, it is repaired with a reverse shoulder arthroplasty. Reverse shoulder arthroplasty allows a greater degree of movement compared to the conventional arthroplasty. In reverse shoulder arthroplasty, the latissimus dorsi tendon is removed from its original insertion and attached to the humerus around the insertion of the deltoid muscle. This change increases the torque and external rotation of the joint and provides better results than the surgeries where the tendon transfer is not done. This article compiles the various etiologies of shoulder dislocation and its treatment, shoulder arthroplasty. It discusses the indications and contraindications of total and reverse total arthroplasty. This article aims to compare conventional shoulder arthroplasty and reverse shoulder arthroplasty. It highlights the advantages of using latissimus dorsi grafts in reverse shoulder arthroplasty in shoulder joint dislocations.

Oral Human Papillomavirus Infection among Smokeless Tobacco-using Tribal Women in Mysuru, India.

Smokeless tobacco (SLT) is consumed by more than 300 million people worldwide. Studies show high use among Indian indigenous women who are also at high risk for oral cancers. Both human papillomavirus infection (HPV) and SLT have been associated with oral cancer, this study examined the presence of high-risk HPV in oral samples collected from tribal smokeless tobacco users in Mysuru, India. Between June and August 2019, 100 tribal females (50 SLT-users and 50 non-users) from rural Mysuru District, Karnataka, were enrolled in a cross-sectional study. Following informed consent, demographic data and oral samples were collected and processed using a digene HC2 High-Risk HPV DNA test (Qiagen, USA). On average participants were 45.5 (SD: ±6.6) years. Chronic SLT users were mostly married (73%), Hindu (100%), illiterate (62%), and employed (90%). One woman was positive for high-risk HPV infection. Oral HPV infection was low in this sample and this is consistent with the literature from other low and middle-income countries. SLT use is high in this group so interventions to reduce tobacco use are warranted.

Immunological Nuances and Complications of Pediatric Organ Transplant: A Narrative Review.

Organ transplantation is considered an exaggerated immune state in which the body reacts in an elaborate cascade of reactions against the lifesaving graft transplanted. Unrepairable organ damage is the main indication for a pediatric patient to undergo a transplant. The host and the donor must fulfill the criteria for a successful transplant to have as few side effects as possible. There has been much-needed research in the domain of surgery of organ transplantation, thereby extending into the pediatric age group. This article elaborates on the post-transplant management, the immuno-biochemistry aspect, and its post-surgery treatment. The post-surgery period requires great emphasis as morbidity and mortality are highest. There is much to understand about managing transplant patients to avoid complications such as infections, hypertension, or side effects of immunosuppressive drugs. The treating clinician faces the challenges of managing the dose and frequency of immuno-suppressive medicines to prevent complications in the patients. If the dose is inadequate, there are chances of graft rejection. If the immuno-suppression is prolonged, there may be chances of infections in the patient. This article aims to summarize the mechanism of graft rejection and put forth the need for further research about creating a universal protocol for managing a patient's immune system post-transplant. The authors hope this protocol will help the clinician better understand the patient's current state and help in appropriately using immuno-suppressive drugs. It calls upon the need for a reliable and easily repeatable battery of investigations that will help solve this dilemma.

Resistance to Resilience: Understanding Post-surgical Hormone Therapy in Breast Cancer Care.

Breast cancer is one of the most common types of cancer affecting women worldwide. Over the years, breast cancer has become a major public health concern, and its incidence is rising globally. The treatment of breast cancer does not stop with surgical intervention, but adjuvant therapies are administered to improve patient outcomes post-surgery based on the type of breast cancer diagnosed. This review focuses on the value of hormone therapy (HT) in improving the prognosis of breast cancer patients and why adhering to adjuvant treatment post-surgery is difficult for patients. HT aims to reduce the chances of breast cancer recurrence after surgical treatment. Even though HT is life-saving, patients tend to not adhere to the therapy due to various factors such as side effects, age-related issues, and socioeconomic status. Most patients stop adhering to the therapy as the duration can be as long as 5-10 years, and the quality of life is greatly impacted due to the side effects of the treatment. This review examines the possible factors leading to non-adherence to HT and tries to propose possible interventions that might improve patient compliance with the treatment. This article not only focuses on the impact of side effects of HT on patients' quality of life but also tries to understand the problems faced by breast cancer patients in adhering to HT.

The Application of Deep Learning to Electroencephalograms, Magnetic Resonance Imaging, and Implants for the Detection of Epileptic Seizures: A Narrative Review.

Epilepsy is a neurological disorder characterized by recurrent seizures affecting millions worldwide. Medically intractable seizures in epilepsy patients are not only detrimental to the quality of life but also pose a significant threat to their safety. Outcomes of epilepsy therapy can be improved by early detection and intervention during the interictal window period. Electroencephalography is the primary diagnostic tool for epilepsy, but accurate interpretation of seizure activity is challenging and highly time-consuming. Machine learning (ML) and deep learning (DL) algorithms enable us to analyze complex EEG data, which can not only help us diagnose but also locate epileptogenic zones and predict medical and surgical treatment outcomes. DL models such as convolutional neural networks (CNNs), inspired by visual processing, can be used to classify EEG activity. By applying preprocessing techniques, signal quality can be enhanced by denoising and artifact removal. DL can also be incorporated into the analysis of magnetic resonance imaging (MRI) data, which can help in the localization of epileptogenic zones in the brain. Proper detection of these zones can help in good neurosurgical outcomes. Recent advancements in DL have facilitated the implementation of these systems in neural implants and wearable devices, allowing for real-time seizure detection. This has the potential to transform the management of drug-refractory epilepsy. This review explores the application of ML and DL techniques to Electroencephalograms (EEGs), MRI, and wearable devices for epileptic seizure detection. This review briefly explains the fundamentals of both artificial intelligence (AI) and DL, highlighting these systems' potential advantages and undeniable limitations.

Single-cell RNA sequencing reveals characteristics of myeloid cells in pulmonary post-acute sequelae of SARS-CoV-2.

Background: Although our understanding of the immunopathology and subsequent risk and severity of COVID-19 disease is evolving, a detailed account of immune responses that contribute to the long-term consequences of pulmonary complication in COVID-19 infection remain unclear. Few studies have detailed the immune and cytokine profiles associated with post-acute sequalae of SARS-CoV-2 infection with persistent pulmonary symptoms (PPASC). However, the dysregulation of the immune system that drives pulmonary sequelae in COVID-19 survivors and PASC sufferers remains largely unknown. Results: To characterize the immunological features of pulmonary PASC (PPASC), we performed droplet-based single-cell RNA sequencing to study the transcriptomic profiles of peripheral blood mononuclear cells (PBMCs) from participants naïve to SARS-CoV-2 (Control) and infected with SARS-CoV-2 with chronic pulmonary symptoms (PPASC). We analyzed more than 34,139 PBMCs by integrating our dataset with previously reported control datasets (GSM4509024) cell distribution. In total, 11 distinct cell populations were identified based on the expression of canonical markers. The proportion of myeloid-lineage cells ([MLCs]; CD14 + /CD16 + monocytes and dendritic cells) was increased in PPASC compared to controls. MLCs from PPASC displayed up-regulation of genes associated with pulmonary symptoms/fibrosis, while glycolysis metabolism-related genes were downregulated. Similarly, pathway analysis showed that fibrosis- related ( VEGF , WNT , and SMAD ) and cell death pathways were up-regulated, but immune pathways were down-regulated in PPASC. In PPASC, we observed interactive VEGF ligand- receptor pairs among MLCs, and network modules in CD14 + (cluster 4) and CD16 + (Cluster 5) monocytes displayed a significant enrichment for biological pathways linked to adverse COVID- 19 outcomes, fibrosis, and angiogenesis. Further analysis revealed a distinct metabolic alteration in MLCs with a down-regulation of glycolysis/gluconeogenesis in PPASC compared to SARS- CoV-2 naïve samples. Conclusion: This study offers valuable insights into the immune response and cellular landscape in PPASC. The presence of elevated MLC levels and their corresponding gene signatures associated with fibrosis, immune response suppression, and altered metabolic states suggests their potential role as a driver of PPASC.

The anti-viral immune response of the adult host robustly modulates neural stem cell activity in spatial, temporal, and sex-specific manners.

Viruses induce a wide range of neurological sequelae through the dysfunction and death of infected cells and persistent inflammation in the brain. Neural stem cells (NSCs) are often disturbed during viral infections. Although some viruses directly infect and kill NSCs, the antiviral immune response may also indirectly affect NSCs. To better understand how NSCs are influenced by a productive immune response, where the virus is successfully resolved and the host survives, we used the CD46+ mouse model of neuron-restricted measles virus (MeV) infection. As NSCs are spared from direct infection in this model, they serve as bystanders to the antiviral immune response initiated by selective infection of mature neurons. MeV-infected mice showed distinct regional and temporal changes in NSCs in the primary neurogenic niches of the brain, the hippocampus and subventricular zone (SVZ). Hippocampal NSCs increased throughout the infection (7 and 60 days post-infection; dpi), while mature neurons transiently declined at 7 dpi and then rebounded to basal levels by 60 dpi. In the SVZ, NSC numbers were unchanged, but mature neurons declined even after the infection was controlled at 60 dpi. Further analyses demonstrated sex, temporal, and region-specific changes in NSC proliferation and neurogenesis throughout the infection. A relatively long-term increase in NSC proliferation and neurogenesis was observed in the hippocampus; however, neurogenesis was reduced in the SVZ. This decline in SVZ neurogenesis was associated with increased immature neurons in the olfactory bulb in female, but not male mice, suggesting potential migration of newly-made neurons out of the female SVZ. These sex differences in SVZ neurogenesis were accompanied by higher infiltration of B cells and greater expression of interferon-gamma and interleukin-6 in female mice. Learning, memory, and olfaction tests revealed no overt behavioral changes after the acute infection subsided. These results indicate that antiviral immunity modulates NSC activity in adult mice without inducing gross behavioral deficits among those tested, suggestive of mechanisms to restore neurons and maintain adaptive behavior, but also revealing the potential for robust NSC disruption in subclinical infections.

Invariant neural dynamics drive commands to control different movements.

It has been proposed that the nervous system has the capacity to generate a wide variety of movements because it reuses some invariant code. Previous work has identified that dynamics of neural population activity are similar during different movements, where dynamics refer to how the instantaneous spatial pattern of population activity changes in time. Here, we test whether invariant dynamics of neural populations are actually used to issue the commands that direct movement. Using a brain-machine interface (BMI) that transforms rhesus macaques' motor-cortex activity into commands for a neuroprosthetic cursor, we discovered that the same command is issued with different neural-activity patterns in different movements. However, these different patterns were predictable, as we found that the transitions between activity patterns are governed by the same dynamics across movements. These invariant dynamics are low dimensional, and critically, they align with the BMI, so that they predict the specific component of neural activity that actually issues the next command. We introduce a model of optimal feedback control (OFC) that shows that invariant dynamics can help transform movement feedback into commands, reducing the input that the neural population needs to control movement. Altogether our results demonstrate that invariant dynamics drive commands to control a variety of movements and show how feedback can be integrated with invariant dynamics to issue generalizable commands.

Determining the Time of Booster Dose Based on the Half-Life and Neutralization Titers against SARS-CoV-2 Variants of Concern in Fully Vaccinated Individuals.

Although mRNA-based COVID-19 vaccines reduce the risk of severe disease, hospitalization and death, vaccine effectiveness (VE) against infection and disease from variants of concern (VOC) wanes over time. Neutralizing antibodies (NAb) are surrogates of protection and are enhanced by a booster dose, but their kinetics and durability remain understudied. Current recommendation of a booster dose does not consider the existing NAb in each individual. Here, we investigated 50% neutralization (NT50) titers against VOC among COVID-19-naive participants receiving the Moderna (n = 26) or Pfizer (n = 25) vaccine for up to 7 months following the second dose, and determined their half-lives. We found that the time it took for NT50 titers to decline to 24, equivalent to 50% inhibitory dilution of 10 international units/mL, was longer in the Moderna (325/324/235/274 days for the D614G/alpha/beta/delta variants) group than in the Pfizer (253/252/174/226 days) group, which may account for the slower decline in VE of the Moderna vaccine observed in real-world settings and supports our hypothesis that measuring the NT50 titers against VOC, together with information on NAb half-lives, can be used to dictate the time of booster vaccination. Our study provides a framework to determine the optimal time of a booster dose against VOC at the individual level. In response to future VOC with high morbidity and mortality, a quick evaluation of NAb half-lives using longitudinal serum samples from clinical trials or research programs of different primary-series vaccinations and/or one or two boosters could provide references for determining the time of booster in different individuals. IMPORTANCE Despite improved understanding of the biology of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), the evolutionary trajectory of the virus is uncertain, and the concern of future antigenically distinct variants remains. Current recommendations for a COVID-19 vaccine booster dose are primarily based on neutralization capacity, effectiveness against circulating variants of concern (VOC), and other host factors. We hypothesized that measuring neutralizing antibody titers against SARS-CoV-2 VOC together with half-life information can be used to dictate the time of booster vaccination. Through detailed analysis of neutralizing antibodies against VOC among COVID-19-naive vaccinees receiving either of two mRNA vaccines, we found that the time it took for 50% neutralization titers to decline to a reference level of protection was longer in the Moderna than in the Pfizer group, which supports our hypothesis. In response to future VOC with potentially high morbidity and mortality, our proof-of-concept study provides a framework to determine the optimal time of a booster dose at the individual level.

Rationale and design of a randomized study comparing the Watchman FLX device to DOACs in patients with atrial fibrillation.

BACKGROUND: Percutaneous left atrial appendage (LAA) closure (LAAC) was developed as a nonpharmacologic alternative to oral anticoagulants (OACs) in patients with atrial fibrillation (AF) who are at an increased risk for stroke or systemic embolism. The Watchman device permanently seals off the LAA to prevent thrombi from escaping into the circulation. Previous randomized trials have established the safety and efficacy of LAAC compared to warfarin. However, direct OACs (DOACs) have become the preferred pharmacologic strategy for stroke prevention in patients with AF, and there is limited data comparing Watchman FLX to DOACs in a broad AF patient population. CHAMPION-AF is designed to prospectively determine whether LAAC with Watchman FLX is a reasonable first-line alternative to DOACs in patients with AF who are indicated for OAC therapy. STUDY DESIGN: A total of 3,000 patients with a CHA2DS2-VASc score ≥2 (men) or ≥3 (women) were randomized to Watchman FLX or DOAC in a 1:1 allocation at 142 global clinical sites. Patients in the device arm were to be treated with DOAC and aspirin, DOAC alone, or DAPT for at least 3 months postimplant followed by aspirin or P2Y12 inhibitor for 1-year. Control patients were required to take an approved DOAC for the duration of the trial. Clinical follow-up visits are scheduled at 3- and 12-months, and then annually through 5 years; LAA imaging is required at 4 months in the device group. Two primary end points will be evaluated at 3 years: (1) composite of stroke (ischemic/hemorrhagic), cardiovascular death, and systemic embolism compared for noninferiority, and (2) nonprocedural bleeding (International Society on Thrombosis and Haemostasis [ISTH] major and clinically relevant nonmajor bleeding) tested for superiority in the device arm against DOACs. The third primary noninferiority end point is the composite of ischemic stroke and systemic embolism at 5 years. Secondary end points include 3- and 5-year rates of (1) ISTH-defined major bleeding and (2) the composite of cardiovascular death, all stroke, systemic embolism, and nonprocedural ISTH bleeding. CONCLUSIONS: This study will prospectively evaluate whether LAAC with the Watchman FLX device is a reasonable alternative to DOACs in patients with AF. CLINICAL TRIAL REGISTRATION: NCT04394546.

GPR161 structure uncovers the redundant role of sterol-regulated ciliary cAMP signaling in the Hedgehog pathway.

The orphan G protein-coupled receptor (GPCR) GPR161 is enriched in primary cilia, where it plays a central role in suppressing Hedgehog signaling1. GPR161 mutations lead to developmental defects and cancers2,3,4. The fundamental basis of how GPR161 is activated, including potential endogenous activators and pathway-relevant signal transducers, remains unclear. To elucidate GPR161 function, we determined a cryogenic-electron microscopy structure of active GPR161 bound to the heterotrimeric G protein complex Gs. This structure revealed an extracellular loop 2 that occupies the canonical GPCR orthosteric ligand pocket. Furthermore, we identify a sterol that binds to a conserved extrahelical site adjacent to transmembrane helices 6 and 7 and stabilizes a GPR161 conformation required for Gs coupling. Mutations that prevent sterol binding to GPR161 suppress cAMP pathway activation. Surprisingly, these mutants retain the ability to suppress GLI2 transcription factor accumulation in cilia, a key function of ciliary GPR161 in Hedgehog pathway suppression. By contrast, a protein kinase A-binding site in the GPR161 C-terminus is critical in suppressing GLI2 ciliary accumulation. Our work highlights how unique structural features of GPR161 interface with the Hedgehog pathway and sets a foundation to understand the broader role of GPR161 function in other signaling pathways.