The spinocerebellar ataxia-associated gene Tau tubulin kinase 2 controls the initiation of ciliogenesis.

The primary cilium has critical roles in human development and disease, but the mechanisms that regulate ciliogenesis are not understood. Here, we show that Tau tubulin kinase 2 (TTBK2) is a dedicated regulator of the initiation of ciliogenesis in vivo. We identified a null allele of mouse Ttbk2 based on loss of Sonic hedgehog activity, a signaling pathway that requires the primary cilium. Despite a normal basal body template, Ttbk2 mutants lack cilia. TTBK2 acts at the distal end of the basal body, where it promotes the removal of CP110, which caps the mother centriole, and promotes recruitment of IFT proteins, which build the ciliary axoneme. Dominant truncating mutations in human TTBK2 cause spinocerebellar ataxia type 11 (SCA11); these mutant proteins do not promote ciliogenesis and inhibit ciliogenesis in wild-type cells. We propose that cell-cycle regulators target TTBK2 to the basal body, where it modifies specific targets to initiate ciliogenesis.

Centrosome anchoring regulates progenitor properties and cortical formation.

Radial glial progenitor cells (RGPs) are the major neural progenitor cells that generate neurons and glia in the developing mammalian cerebral cortex1-4. In RGPs, the centrosome is positioned away from the nucleus at the apical surface of the ventricular zone of the cerebral cortex5-8. However, the molecular basis and precise function of this distinctive subcellular organization of the centrosome are largely unknown. Here we show in mice that anchoring of the centrosome to the apical membrane controls the mechanical properties of cortical RGPs, and consequently their mitotic behaviour and the size and formation of the cortex. The mother centriole in RGPs develops distal appendages that anchor it to the apical membrane. Selective removal of centrosomal protein 83 (CEP83) eliminates these distal appendages and disrupts the anchorage of the centrosome to the apical membrane, resulting in the disorganization of microtubules and stretching and stiffening of the apical membrane. The elimination of CEP83 also activates the mechanically sensitive yes-associated protein (YAP) and promotes the excessive proliferation of RGPs, together with a subsequent overproduction of intermediate progenitor cells, which leads to the formation of an enlarged cortex with abnormal folding. Simultaneous elimination of YAP suppresses the cortical enlargement and folding that is induced by the removal of CEP83. Together, these results indicate a previously unknown role of the centrosome in regulating the mechanical features of neural progenitor cells and the size and configuration of the mammalian cerebral cortex.

Maternally derived antibody titer dynamics and risk of hospitalized infant dengue disease.

Infants less than 1 y of age experience high rates of dengue disease in dengue virus (DENV) endemic countries. This burden is commonly attributed to antibody-dependent enhancement (ADE), whereby concentrations of maternally derived DENV antibodies become subneutralizing, and infection-enhancing. Understanding antibody-related mechanisms of enhanced infant dengue disease risk represents a significant challenge due to the dynamic nature of antibodies and their imperfect measurement processes. Further, key uncertainties exist regarding the impact of long-term shifts in birth rates, population-level infection risks, and maternal ages on the DENV immune landscape of newborns and their subsequent risks of severe dengue disease in infancy. Here, we analyze DENV antibody data from two infant cohorts (N = 142 infants with 605 blood draws) and 40 y of infant dengue hospitalization data from Thailand. We use mathematical models to reconstruct maternally derived antibody dynamics, accounting for discretized measurement processes and limits of assay detection. We then explore possible antibody-related mechanisms of enhanced infant dengue disease risk and their ability to reconstruct the observed age distribution of hospitalized infant dengue cases. We find that ADE mechanisms are best able to reconstruct the observed data. Finally, we describe how the shifting epidemiology of dengue in Thailand, combined with declining birth rates, have decreased the absolute risk of infant dengue disease by 88% over a 40-y period while having minimal impact on the mean age of infant hospitalized dengue disease.

Dengue.

Dengue, caused by four closely related viruses, is a growing global public health concern, with outbreaks capable of overwhelming health-care systems and disrupting economies. Dengue is endemic in more than 100 countries across tropical and subtropical regions worldwide, and the expanding range of the mosquito vector, affected in part by climate change, increases risk in new areas such as Spain, Portugal, and the southern USA, while emerging evidence points to silent epidemics in Africa. Substantial advances in our understanding of the virus, immune responses, and disease progression have been made within the past decade. Novel interventions have emerged, including partially effective vaccines and innovative mosquito control strategies, although a reliable immune correlate of protection remains a challenge for the assessment of vaccines. These developments mark the beginning of a new era in dengue prevention and control, offering promise in addressing this pressing global health issue.

Assessing the role of multiple mechanisms increasing the age of dengue cases in Thailand.

The mean age of dengue hemorrhagic fever (DHF) cases increased considerably in Thailand from 8.1 to 24.3 y between 1981 and 2017 (mean annual increase of 0.45 y). Alternative proposed explanations for this trend, such as changes in surveillance practices, reduced mosquito­human contact, and shifts in population demographics, have different implications for global dengue epidemiology. To evaluate the contribution of each of these hypothesized mechanisms to the observed data, we developed 20 nested epidemiological models of dengue virus infection, allowing for variation over time in population demographics, infection hazards, and reporting rates. We also quantified the effect of removing or retaining each source of variation in simulations of the age trajectory. Shifts in the age structure of susceptibility explained 58% of the observed change in age. Adding heterogeneous reporting by age and reductions in per-serotype infection hazard to models with shifts in susceptibility explained an additional 42%. Reductions in infection hazards were mostly driven by changes in the number of infectious individuals at any time (another consequence of shifting age demographics) rather than changes in the transmissibility of individual infections. We conclude that the demographic transition drives the overwhelming majority of the observed change as it changes both the age structure of susceptibility and the number of infectious individuals. With the projected Thai population age structure, our results suggest a continuing increase in age of DHF cases, shifting the burden toward individuals with more comorbidity. These insights into dengue epidemiology may be relevant to many regions of the globe currently undergoing comparable changes in population demographics.

Protective Role of NS1-Specific Antibodies in the Immune Response to Dengue Virus through Antibody-Dependent Cellular Cytotoxicity.

BACKGROUND: Dengue virus (DENV) non-structural protein 1 (NS1) has multiple functions within infected cells, on the cell surface, and in secreted form, and is highly immunogenic. Immunity from previous DENV infections is known to exert both positive and negative effects on subsequent DENV infections, but the contribution of NS1-specific antibodies to these effects is incompletely understood. METHODS: We investigated the functions of NS1-specific antibodies and their significance in DENV infection. We analyzed plasma samples collected in a prospective cohort study prior to symptomatic or subclinical secondary DENV infection. We measured binding to purified recombinant NS1 protein and to NS1-expressing CEM cells, antibody-mediated NK cell activation by plate-bound NS1 protein, and antibody-dependent cellular cytotoxicity (ADCC) of NS1-expressing target cells. RESULTS: We found that antibody responses to NS1 were highly serotype-cross-reactive and that subjects who experienced subclinical DENV infection had significantly higher antibody responses to NS1 in pre-infection plasma than subjects who experienced symptomatic infection. We observed strong positive correlations between antibody binding and NK activation. CONCLUSIONS: These findings demonstrate the involvement of NS1-specific antibodies in ADCC and provide evidence for a protective effect of NS1-specific antibodies in secondary DENV infection.

Wastewater Surveillance for Infectious Disease: A Systematic Review.

Wastewater surveillance for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been shown to be a valuable source of information regarding SARS-CoV-2 transmission and coronavirus disease 2019 (COVID-19) cases. Although the method has been used for several decades to track other infectious diseases, there has not been a comprehensive review outlining all of the pathogens that have been surveilled through wastewater. Herein we identify the infectious diseases that have been previously studied via wastewater surveillance prior to the COVID-19 pandemic. Infectious diseases and pathogens were identified in 100 studies of wastewater surveillance across 38 countries, as were themes of how wastewater surveillance and other measures of disease transmission were linked. Twenty-five separate pathogen families were identified in the included studies, with the majority of studies examining pathogens from the family Picornaviridae, including polio and nonpolio enteroviruses. Most studies of wastewater surveillance did not link what was found in the wastewater to other measures of disease transmission. Among those studies that did, the value reported varied by study. Wastewater surveillance should be considered as a potential public health tool for many infectious diseases. Wastewater surveillance studies can be improved by incorporating other measures of disease transmission at the population-level including disease incidence and hospitalizations.

Athletes in medicine: A systematic review of performance of athletes in medicine.

INTRODUCTION: As interest in medicine grows, admissions committees must review an increasingly competitive pool of medical school and residency candidates. Nearly all admissions committees have moved towards a holistic review, which considers an applicant's experiences and attributes in addition to academic metrics. As such, identifying nonacademic predictors of success in medicine is necessary. Parallels between skills necessary to succeed in athletics and in medicine have been drawn, including teamwork, discipline and resiliency. This systematic review synthesises the current literature to evaluate the relationship between participation in athletics and performance in medicine. METHODS: The authors searched five databases to conduct a systematic review following PRISMA guidelines. Included studies assessed medical students, residents or attending physicians in the United States or Canada and used prior athletic participation as a predictor or explanatory variable. The review examined associations between prior athletic participation and outcomes in medical school, residency and/or as an attending physician. RESULTS: Eighteen studies evaluating medical students (78%), residents (28%) or attending physicians (6%) met inclusion criteria for this systematic review. Twelve (67%) studies specifically assessed participants based on skill level, and five (28%) studies specifically assessed participants based on type of athletic participation (team versus individual). Sixteen studies (89%) found that former athletes performed significantly better than their counterparts (p < 0.05). These studies found significant associations between prior athletic participation and better outcomes in multiple performance indicators, including exam scores, faculty ratings, surgical errors and burnout. CONCLUSIONS: Current literature, although limited, suggests that prior participation in athletics may be a predictor of success in medical school and residency. This was demonstrated through objective scoring methods, such as USMLE, and subjective outcomes, such as faculty ratings and burnout. Specifically, multiple studies indicate that former athletes demonstrated increased surgical skill proficiency and decreased burnout as medical students and residents.

Ultrasound guided lumbar erector spinae block: A case series on a novel technique for the treatment of acute low Back pain.

Low back pain is among one of the most common presentations to the emergency department (ED). Regional anesthesia has recently gained traction as an option for analgesia in ED patients, especially in the wake of the opioid epidemic. Data on lumbar application of the ESPB in the setting of acute, refractory low back pain in the ED is scarce. We describe a series of three cases of patients who presented to the ED with severe low back pain refractory to traditional therapy, successfully treated using lumbar ESPB. Lumbar ESPB may be an effective approach to achieving rapid analgesia in patients who present with low back pain who may otherwise be poor candidates for more traditional therapy, such as with opioids or NSAIDs, or who may have refractory pain despite use of these medications.

Centrioles control the capacity, but not the specificity, of cytotoxic T cell killing.

Immunological synapse formation between cytotoxic T lymphocytes (CTLs) and the target cells they aim to destroy is accompanied by reorientation of the CTL centrosome to a position beneath the synaptic membrane. Centrosome polarization is thought to enhance the potency and specificity of killing by driving lytic granule fusion at the synapse and thereby the release of perforin and granzymes toward the target cell. To test this model, we employed a genetic strategy to delete centrioles, the core structural components of the centrosome. Centriole deletion altered microtubule architecture as expected but surprisingly had no effect on lytic granule polarization and directional secretion. Nevertheless, CTLs lacking centrioles did display substantially reduced killing potential, which was associated with defects in both lytic granule biogenesis and synaptic actin remodeling. These results reveal an unexpected role for the intact centrosome in controlling the capacity but not the specificity of cytotoxic killing.

Ordered Regression Models: a Tutorial.

Ordinal outcomes are common in the social, behavioral, and health sciences, but there is no commonly accepted approach to analyzing them. Researchers make a number of different seemingly arbitrary recoding decisions implying different levels of measurement and theoretical assumptions. As a result, a wide array of models are used to analyze ordinal outcomes, including the linear regression model, binary response model, ordered models, and count models. In this tutorial, we present a diverse set of ordered models (most of which are under-utilized in applied research) and argue that researchers should approach the analysis of ordinal outcomes in a more systematic fashion by taking into consideration both theoretical and empirical concerns, and prioritizing ordered models given the flexibility they provide. Additionally, we consider the challenges that ordinal independent variables pose for analysts that often go unnoticed in the literature and offer simple ways to decide how to include ordinal independent variables in ordered regression models in ways that are easier to justify on conceptual and empirical grounds. We illustrate several ordered regression models with an empirical example, general self-rated health, and conclude with recommendations for building a sounder approach to ordinal data analysis.

Cryptorchidism Review for the Primary Care Provider.

Cryptorchidism, or undescended testes, is the most common disorder of the genitals seen at birth. Due to its high prevalence and short- and long-term sequelae, it is crucial that primary care providers are familiar with the appropriate management of cryptorchidism. This paper serves to review the embryology, diagnosis, management, and treatment of cryptorchidism with the goal of serving as a valuable reference for providers managing pediatric and neonatal urological issues in the primary care setting, using the American Urological Association's most recent guidelines on the subject. Importantly, it also serves as a review of the long-term consequences of cryptorchidism (even after repair) and reinforces the need for continued surveillance for complications throughout a patient's life.

A Retrospective Cohort Study to Evaluate a Swallow Study Use in the NICU Population to Optimize Feeding Support.

INTRODUCTION: Premature neonates demonstrate difficulties with swallowing due to neurological immaturity as well as a weaker suck reflex compared to full term infants. Swallowing starts to mature by 33-34 weeks of gestational age. In neonates, dysphagia is evaluated clinically by speech-language pathologists and a swallow study is ordered for infants with swallowing difficulties. However, leaving the NICU to undergo a swallow study puts infants under environmental stressors and a swallow study exposes infants to radiation. There is a concern that swallow studies are being over-utilized in the NICU. METHODS: All premature infants born before 36 weeks GA admitted to the Sanford Boekelheide NICU between January 2015 and December 2019 who underwent a swallow study were enrolled in data analysis. Deidentified data was collected retrospectively through electronic medical record review and RedCap was utilized for data storage. Infants were divided in two cohorts; those who underwent a feeding change (feeding thickening) following a swallow study vs those who continued with prior feedings. Infant demographics and characteristics were assessed to identify a group of infants who are at high risk of aspiration. RESULTS: A total of 179 infants were identified. DISCUSSION: A swallow study can identify infants at high risk for aspiration, however, many could potentially be avoided by allowing more time for infant maturation.

Individual, Household, and Community Drivers of Dengue Virus Infection Risk in Kamphaeng Phet Province, Thailand.

BACKGROUND: Dengue virus (DENV) often circulates endemically. In such settings with high levels of transmission, it remains unclear whether there are risk factors that alter individual infection risk. METHODS: We tested blood taken from individuals living in multigenerational households in Kamphaeng Phet province, Thailand for DENV antibodies (N = 2364, mean age 31 years). Seropositivity ranged from 45.4% among those 1-5 years old to 99.5% for those >30 years. Using spatially explicit catalytic models, we estimated that 11.8% of the susceptible population gets infected annually. RESULTS: We found that 37.5% of the variance in seropositivity was explained by unmeasured household-level effects with only 4.2% explained by spatial differences between households. The serostatus of individuals from the same household remained significantly correlated even when separated by up to 15 years in age. CONCLUSIONS: These findings show that despite highly endemic transmission, persistent differences in infection risk exist across households, the reasons for which remain unclear.

Healthcare Personnel (HCP) Attitudes About Coronavirus Disease 2019 (COVID-19) Vaccination After Emergency Use Authorization.

BACKGROUND: We previously reported on coronavirus disease 2019 (COVID-19) vaccination intent among healthcare personnel (HCP) before emergency use authorization. We found widespread hesitancy and a substantial proportion of HCP did not intend to vaccinate. METHODS: We conducted a cross-sectional survey of HCP, including clinical and nonclinical staff, researchers, and trainees between 21 February and 19 March 2021. The survey evaluated vaccine attitudes, beliefs, intent, and acceptance. RESULTS: Overall, 3981 (87.7%) of respondents had already received a COVID-19 vaccine or planned to get vaccinated. There were significant differences in vaccine acceptance by gender, age, race, and hospital role. Males (93.7%) were more likely than females (89.8%) to report vaccine acceptance (P < .001). Mean age was higher among those reporting vaccine acceptance (P < .001). Physicians and scientists showed the highest acceptance rate (97.3%), whereas staff in ancillary services showed the lowest acceptance rate (79.9%). Unvaccinated respondents were more likely to be females, to have refused vaccines in the past due to reasons other than illness or allergy, to care for COVID-19 patients, or to rely on themselves when making vaccination decision. Vaccine acceptance was more than twice previous intent among Black respondents, an increase from 30.8% to 73.8%, and across all hospital roles with all > 80% vaccine acceptance. CONCLUSIONS: The majority of HCP were vaccinated, much higher than reporting intent before vaccine was available. However, many HCP-particularly ancillary services-are still hesitant. Feasible and effective interventions to address the hesitant, including individually-tailored education strategies are needed, or vaccine can be mandated.

Naïve human pluripotent stem cells respond to Wnt, Nodal and LIF signalling to produce expandable naïve extra-embryonic endoderm.

Embryonic stem cells (ESCs) exist in at least two states that transcriptionally resemble different stages of embryonic development. Naïve ESCs resemble peri-implantation stages and primed ESCs the pre-gastrulation epiblast. In mouse, primed ESCs give rise to definitive endoderm in response to the pathways downstream of Nodal and Wnt signalling. However, when these pathways are activated in naïve ESCs, they differentiate to a cell type resembling early primitive endoderm (PrE), the blastocyst-stage progenitor of the extra-embryonic endoderm. Here, we apply this context dependency to human ESCs, showing that activation of Nodal and Wnt signalling drives the differentiation of naïve pluripotent cells toward extra-embryonic PrE, or hypoblast, and these can be expanded as an in vitro model for naïve extra-embryonic endoderm (nEnd). Consistent with observations made in mouse, human PrE differentiation is dependent on FGF signalling in vitro, and we show that, by inhibiting FGF receptor signalling, we can simplify naïve pluripotent culture conditions, such that the inhibitor requirements closer resemble those used in mouse. The expandable nEnd cultures reported here represent stable extra-embryonic endoderm, or human hypoblast, cell lines.This article has an associated 'The people behind the papers' interview.

p120-catenin regulates WNT signaling and EMT in the mouse embryo.

Epithelial-to-mesenchymal transitions (EMTs) require a complete reorganization of cadherin-based cell-cell junctions. p120-catenin binds to the cytoplasmic juxtamembrane domain of classical cadherins and regulates their stability, suggesting that p120-catenin may play an important role in EMTs. Here, we describe the role of p120-catenin in mouse gastrulation, an EMT that can be imaged at cellular resolution and is accessible to genetic manipulation. Mouse embryos that lack all p120-catenin, or that lack p120-catenin in the embryo proper, survive to midgestation. However, mutants have specific defects in gastrulation, including a high rate of p53-dependent cell death, a bifurcation of the posterior axis, and defects in the migration of mesoderm; all are associated with abnormalities in the primitive streak, the site of the EMT. In embryonic day 7.5 (E7.5) mutants, the domain of expression of the streak marker Brachyury (T) expands more than 3-fold, from a narrow strip of posterior cells to encompass more than one-quarter of the embryo. After E7.5, the enlarged T+ domain splits in 2, separated by a mass of mesoderm cells. Brachyury is a direct target of canonical WNT signaling, and the domain of WNT response in p120-catenin mutant embryos, like the T domain, is first expanded, and then split, and high levels of nuclear ß-catenin levels are present in the cells of the posterior embryo that are exposed to high levels of WNT ligand. The data suggest that p120-catenin stabilizes the membrane association of ß-catenin, thereby preventing accumulation of nuclear ß-catenin and excessive activation of the WNT pathway during EMT.

Abbreviated Outpatient Upper Extremity Fracture Care to Avoid Clinic and Hospital Environmental Encounters During the COVID-19 Pandemic: A New Approach to Fracture Care?

BACKGROUND: To minimize in-person visits during the COVID-19 pandemic, a new fracture care protocol for children with complete and stable, nondisplaced or minimally displaced upper extremity (UE) fractures has been implemented. This protocol involves immobilization with a bivalved cast, which allows for home cast removal during a telemedicine visit, and no follow-up radiographs, thus eliminating the requirement for a return to clinic. The purpose of this study is to evaluate the outcomes and parent satisfaction of this new abbreviated fracture care protocol. METHODS: Between May 2020 and April 2021, during the COVID-19 pandemic, children with complete and stable, nondisplaced or minimally displaced UE fractures were treated with a bivalved cast and 1 follow-up telemedicine visit for home cast removal. A prospective longitudinal study of these patients was performed. The PROMIS Upper Extremity questionnaire was administered at enrollment and 3 months follow-up. Parents completed a satisfaction survey after home cast removal. Demographic data and information regarding complications were collected. A historical cohort of controls treated with standard cast in 2019 was used for comparison. RESULTS: A total of 56 patients with a mean age of 8±3 years (range 2 to 15) were prospectively enrolled in this study. Parent-reported PROMIS Upper Extremity scores showed a significant increase from 24.9 (95% confidence interval=20.8-29.1) at enrollment to 51.6 (95% confidence interval=50.8-52.5) at 3 months follow-up (P<0.001). Results of the satisfaction survey (n=39) showed all parents were either very satisfied (85%) or satisfied (15%). In addition, 10% of parents would have initially preferred to come into clinic for cast removal and 90% of parents would prefer this new treatment plan in the future. Patients in the abbreviated care cohort returned to clinic for a median 1 in-person visits, compared with 2 for historical controls (n=183, P<0.001). Abbreviated care patients received fewer (1.0) radiographs than controls (2.0, P<0.001). Complication rate did not differ between the groups (P=0.77). CONCLUSIONS: Complete and stable, nonminimally or minimally displaced UE fractures can be cared for safely and effectively in a single in-person visit, with a telemedicine cast removal visit. Parents are satisfied with this abbreviated protocol and prefer it to additional in-person visits. LEVEL OF EVIDENCE: Level III.

ß-Pix directs collective migration of anterior visceral endoderm cells in the early mouse embryo.

Collective epithelial migration is important throughout embryonic development. The underlying mechanisms are poorly understood but likely involve spatially localized activation of Rho GTPases. We previously reported that Rac1 is essential for generating the protrusive activity that drives the collective migration of anterior visceral endoderm (AVE) cells in the early mouse embryo. To identify potential regulators of Rac1, we first performed an RNAi screen of Rho family exchange factors (guanine nucleotide exchange factor [GEF]) in an in vitro collective epithelial migration assay and identified ß-Pix. Genetic deletion of ß-Pix in mice disrupts collective AVE migration, while high-resolution live imaging revealed that this is associated with randomly directed protrusive activity. We conclude that ß-Pix controls the spatial localization of Rac1 activity to drive collective AVE migration at a critical stage in mouse development.

A Concise Review of Neonatal Dermatology.

Skin findings in neonates carry a wide differential diagnosis, ranging from self-limiting rashes to something more sinister, as cutaneous changes can be an indicator of a serious underlying infectious process. Even benign rashes can cause great concern for families and providers. Pathologic rashes pose a potential risk to the neonate's health. Therefore, it is important to diagnose skin findings and provide any necessary treatment swiftly and accurately. This article provides a concise review of neonatal dermatology with the goal to aid providers in diagnosing and managing neonatal skin conditions.