Wrapping of single-stranded DNA by Replication Protein A and modulation through phosphorylation.

Single-stranded DNA (ssDNA) intermediates, which emerge during DNA metabolic processes are shielded by Replication Protein A (RPA). RPA binds to ssDNA and acts as a gatekeeper, directing the ssDNA towards downstream DNA metabolic pathways with exceptional specificity. Understanding the mechanistic basis for such RPA-dependent specificity requires a comprehensive understanding of the structural conformation of ssDNA when bound to RPA. Previous studies suggested a stretching of ssDNA by RPA. However, structural investigations uncovered a partial wrapping of ssDNA around RPA. Therefore, to reconcile the models, in this study, we measured the end-to-end distances of free ssDNA and RPA-ssDNA complexes using single-molecule FRET and Double Electron-Electron Resonance (DEER) spectroscopy and found only a small systematic increase in the end-to-end distance of ssDNA upon RPA binding. This change does not align with a linear stretching model but rather supports partial wrapping of ssDNA around the contour of DNA binding domains of RPA. Furthermore, we reveal how phosphorylation at the key Ser-384 site in the RPA70 subunit provides access to the wrapped ssDNA by remodeling the DNA-binding domains. These findings establish a precise structural model for RPA-bound ssDNA, providing valuable insights into how RPA facilitates the remodeling of ssDNA for subsequent downstream processes.

Microstructural Changes in the Brainstem Auditory Pathway in Children With Hearing Loss.

OBJECTIVE: To assess the utility of diffusion tensor imaging of the auditory pathway in children with sensorineural hearing loss (SNHL). STUDY DESIGN: Retrospective cohort study. SETTING: A single academic tertiary children's hospital. PATIENTS: Sixteen pediatric patients with bilateral SNHL of at least moderate severity in the poorer ear (eight male; mean age, 5.3 ± 4.9 yrs). Controls consisted of age- and sex-matched children with normal hearing who were imaged for nonotologic, non-neurologic medical concerns and found to have normal magnetic resonance imaging (MRI). INTERVENTIONS: Three Tesla MRI scanners were used for diffusion tensor imaging. MAIN OUTCOME MEASURES: Quantitative diffusion tensor metrics were extracted from the superior olivary nucleus (SON), inferior colliculus (IC), and ipsilateral fiber tracts between the SON and IC delineated by tractography. RESULTS: We identified differences in fractional anisotropy of the SON between the SNHL cohort and controls (0.377 ± 0.056 vs. 0.422 ± 0.052; p = 0.009), but not in the IC. There were no differences in the mean diffusivity (MD) values in the IC and SON. Among younger children (≤5 yrs), MD was decreased in the SNHL cohort compared with controls in the IC (0.918 ± 0.051 vs. 1.120 ± 0.142; p < 0.001). However, among older children (>5 yrs), there were no differences in MD (1.124 ± 0.198 vs. 0.997 ± 0.103; p = 0.119). There were no differences in MD or fractional anisotropy in the white matter fibers of the IC-SON tract. CONCLUSIONS: Our results suggest abnormal neural tracts along the central auditory pathway among children with SNHL. Longitudinal studies should assess the prognostic value of these MRI-based findings for assessing long-term outcomes and determining intervention efficacy.

Congenital Cytomegalovirus Testing Outcomes From the ValEAR Trial.

OBJECTIVE: To determine the positivity rate of congenital cytomegalovirus (cCMV) testing among universal, hearing-targeted CMV testing (HT-cCMV) and delayed targeted dried blood spot (DBS) testing newborn screening programs, and to examine the characteristics of successful HT-cCMV testing programs. STUDY DESIGN: Prospective survey of birth hospitals performing early CMV testing. SETTING: Multiple institutions. METHODS: Birth hospitals participating in the National Institutes of Health ValEAR clinical trial were surveyed to determine the rates of cCMV positivity associated with 3 different testing approaches: universal testing, HT-cCMV, and DBS testing. A mixed methods model was created to determine associations between successful HT-cCMV screening and specific screening protocols. RESULTS: Eighty-two birth hospitals were surveyed from February 2019 to December 2021. Seven thousand six hundred seventy infants underwent universal screening, 9017 infants HT-cCMV and 535 infants delayed DBS testing. The rates of cCMV positivity were 0.5%, 1.5%, and 7.3%, respectively. The positivity rate for universal CMV screening was less during the COVID-19 pandemic than that reported prior to the pandemic. There were no statistically significant drops in positivity for any approach during the pandemic. For HT-cCMV testing, unique order sets and rigorous posttesting protocols were associated with successful screening programs. CONCLUSION: Rates of cCMV positivity differed among the 3 approaches. The rates are comparable to cohort studies reported in the literature. Universal CMV prevalence decreased during the pandemic but not significantly. Institutions with specific order set for CMV testing where the primary care physician orders the test and the nurse facilitates the testing process exhibited higher rates of HT-cCMV testing.

The safety and efficacy of radiofrequency ablation in benign pediatric thyroid disease in the US: An initial case series.

Objective: To evaluate the efficacy and safety of radiofrequency ablation (RFA) for benign nonfunctional thyroid nodules or functional lingual thyroid gland in a pediatric population. Methods: Four pediatric patients (four female; mean age 13.50 ± 4.04, range 8-17 years) with either benign thyroid nodules or mildly obstructive lingual thyroid glands were treated with RFA from 2020 to 2021 were evaluated. The inclusion criteria for RFA therapy were (i) age < 18 years; (ii) benign cytopathological results on ultrasound guided fine needle aspiration; (iii) pressure or pain symptoms caused by the thyroid nodules; (iv) dysphagia or obstruction caused by the lingual thyroid tissue; (v) follow up for >6 months with otolaryngology or endocrinology. Results: Two patients had benign non-functioning thyroid nodules and two had mildly obstructive functioning lingual thyroid glands. Mean follow up was 10.75 ± 4.79 months. Each patient underwent one RFA session with no complications. For the patients with thyroid nodules, there was >74% reduction in nodule size at last follow up with improvement in neck swelling and pain. For the patients with lingual thyroid glands, both did not have any other functional thyroid gland identified. Both had visible decrease in size of the gland as visualized transorally with improvement in dysphagia and obstructive symptoms when lying flat. Conclusion: RFA is a safe and effective option for managing benign thyroid nodules and lingual thyroid glands in a pediatric patient population. Level of evidence: 4.

Förster resonance energy transfer within the neomycin aptamer.

Förster resonance energy transfer (FRET) measurements between two dyes is a powerful method to interrogate both structure and dynamics of biopolymers. The intensity of a fluorescence signal in a FRET measurement is dependent on both the distance and the relative orientation of the dyes. The latter can at the same time both complicate the analysis and give more detailed information. Here we present a detailed spectroscopic study of the energy transfer between the rigid FRET labels Çmf (donor) and tCnitro (quencher/acceptor) within the neomycin aptamer N1. The energy transfer originates from multiple emitting states of the donor and occurs on a low picosecond to nanosecond time-scale. To fully characterize the energy transfer, ultrafast transient absorption measurements were performed in conjunction with static fluorescence and time-correlated single photon counting (TCSPC) measurements, showing a clear distance dependence of both signal intensity and lifetime. Using a known NMR structure of the ligand-bound neomycin aptamer, the distance between the two labels was used to estimate κ2 and, therefore, make qualitative statements about the change in orientation after ligand binding with unprecedented temporal and spatial resolution. The advantages and potential applications of absorption-based methods using rigid labels for the characterization of FRET processes are discussed.

Canal wall up versus canal wall down mastoidectomy techniques in the pediatric population with cholesteatoma: A systematic review and meta-analysis of comparative studies.

IMPORTANCE: The optimal surgical management of cholesteatoma remains controversial. Within pediatric otolaryngology, one of the most vital points of contention is the selection of canal wall-up (CWU) versus canal wall-down (CWD) procedures. Pediatric cholesteatoma has high rates of recurrence (16%-54%). In adults, there is evidence that the selection of surgical techniques affects recurrence rates. This has not been shown in children. OBJECTIVES: 1. To systematically review the literature on recurrent and residual cholesteatoma after CWU and CWD in children and perform a meta-analysis of the data. 2. To assess the rates of recurrent and residual cholesteatoma between CWU and CWD techniques in pediatric patients. 3. To assess hearing outcomes by evaluating postoperative differences in the air-bone gap (ABG) between CWU and CWD techniques. DATA SOURCES: A systematic search of PubMed, Embase, Scopus, and Cochrane Collaboration was performed from inception to May 1st, 2020, to identify studies that compared CWU and CWD procedures for acquired cholesteatoma in children. STUDY SELECTION: Search records were screened in duplicate by four reviewers. Inclusion criteria consisted of comparative randomized clinical trials and observational studies assessing outcomes of CWU and CWD techniques in the pediatric population. Studies involving patients with congenital cholesteatoma were excluded. DATA EXTRACTION AND SYNTHESIS: Four reviewers working independently and in duplicate systematically reviewed and extracted study data. Dichotomous variables were analyzed as risk ratios (RR), while continuous variables were compared using weighted mean differences (MD). The risk of bias was assessed using the CLARITY Scale. PRIMARY OUTCOMES AND MEASURES: The outcomes were recurrence, residual disease, air-bone gap (ABG), and air conductive (AC) thresholds. RESULTS: After screening 1036 publications, 17 retrospective cohort studies were selected. 1333 children were included; the overall mean age was ten years (SD 7.9), and the overall mean follow-up time was 5.9 years (SD 6.6). CWU and CWD techniques were performed in 60% (796) and 40% (537) cases. We did not find differences in cholesteatoma recurrence (RR: 1.50, 95% CI 0.94; 2.40; n = 544; I2 0%; Tau [2]: 0.00), or rates of residual cholesteatoma (RR 1.51, 95% CI 0.96; 2.38, n = 506; I2: 0%; Tau [2]: 0.00) in patients who underwent CWU and CWD mastoidectomy. The mean air-bone gap was lower with CWU than CWD (mean difference: 7.60, 95% CI -10.65; -4.54; n = 242; I2: 71%; Tau [2]: 5.98). CONCLUSION: and relevance: We show similar rates of recurrence and residual disease after either CWU or CWD tympanoplasty. Our results challenge the fundamental principle of CWD surgery as a standard technique, as there is no difference in rates of recurrence and residual disease in CWU and CWD. Moreover, audiometric results support CWU with improved hearing outcomes. TRIAL REGISTRATION: PROSPERO identifier: CRD42020184029.

Imaging guidance for cholesteatoma surgery using tissue autofluorescence.

Significance: Cholesteatoma is an expansile destructive lesion of the middle ear and mastoid, which can result in significant complications by eroding adjacent bony structures. Currently, there is an inability to accurately distinguish cholesteatoma tissue margins from middle ear mucosa tissue, causing a high recidivism rate. Accurately differentiating cholesteatoma and mucosa will enable a more complete removal of the tissue. Aim: Develop an imaging system to enhance the visibility of cholesteatoma tissue and margins during surgery. Approach: Cholesteatoma and mucosa tissue samples were excised from the inner ear of patients and illuminated with 405, 450, and 520 nm narrowband lights. Measurements were made with a spectroradiometer equipped with a series of different longpass filters. Images were obtained using a red-green-blue (RGB) digital camera equipped with a long pass filter to block reflected light. Results: Cholesteatoma tissue fluoresced under 405 and 450 nm illumination. Middle ear mucosa tissue did not fluoresce under the same illumination and measurement conditions. All measurements were negligible under 520 nm illumination conditions. All spectroradiometric measurements of cholesteatoma tissue fluorescence can be predicted by a linear combination of emissions from keratin and flavin adenine dinucleotide. We built a prototype of a fluorescence imaging system using a 495 nm longpass filter in combination with an RGB camera. The system was used to capture calibrated digital camera images of cholesteatoma and mucosa tissue samples. The results confirm that cholesteatoma emits light when it is illuminated with 405 and 450 nm, whereas mucosa tissue does not. Conclusions: We prototyped an imaging system that is capable of measuring cholesteatoma tissue autofluorescence.

Frequency-swept dynamic nuclear polarization.

Dynamic nuclear polarization (DNP) improves the sensitivity of NMR spectroscopy by the transfer of electron polarization to nuclei via irradiation of electron-nuclear transitions with microwaves at the appropriate frequency. For fields > 5 T and using g ∼ 2 electrons as polarizing agents, this requires the availability of microwave sources operating at >140 GHz. Therefore, microwave sources for DNP have generally been continuous-wave (CW) gyrotrons, and more recently solid state, oscillators operating at a fixed frequency and power. This constraint has limited the DNP mechanisms which can be exploited, and stymied the development of new time domain mechanisms. We report here the incorporation of a microwave source enabling facile modulation of frequency, amplitude, and phase at 9 T (250 GHz microwave frequency), and we have used the source for magic-angle spinning (MAS) NMR experiments. The experiments include investigations of CW DNP mechanisms, the advantage of frequency-chirped irradiation, and a demonstration of an Overhauser enhancement of ∼25 with a recently reported water-soluble BDPA radical, highlighting the potential for affordable and compact microwave sources to achieve significant enhancement in aqueous samples, including biological macromolecules. With the development of suitable microwave amplifiers, it should permit exploration of multiple new avenues involving time domain experiments.

Solid-Effect Dynamic Nuclear Polarization in Viscous Liquids at 9.4 T Using Narrow-Line Polarizing Agents.

Dynamic nuclear polarization (DNP) is a hyperpolarization method that is widely used for increasing the sensitivity of nuclear magnetic resonance (NMR) experiments. DNP is efficient in solid-state and liquid-state NMR, but its implementation in the intermediate state, namely, viscous media, is still less explored. Here, we show that a 1H DNP enhancement of over 50 can be obtained in viscous liquids at a magnetic field of 9.4 T and a temperature of 315 K. This was accomplished by using narrow-line polarizing agents in glycerol, both the water-soluble α,γ-bisdiphenylen-ß-phenylallyl (BDPA) and triarylmethyl radicals, and a microwave/RF double-resonance probehead. We observed DNP enhancements with a field profile indicative of the solid effect and investigated the influence of microwave power, temperature, and concentration on the 1H NMR results. To demonstrate potential applications of this new DNP approach for chemistry and biology, we show hyperpolarized 1H NMR spectra of tripeptides, triglycine, and glypromate, in glycerol-d8.

Prevalence of Cochlear Nerve Deficiency and Hearing Device Use in Children With Single-Sided Deafness.

OBJECTIVE: This study aimed to assess the prevalence of cochlear nerve deficiency (CND) in a cohort of pediatric patients with single-sided deafness (SSD). A secondary objective was to investigate trends in intervention and hearing device use in these children. STUDY DESIGN: Case series with chart review. SETTING: Pediatric tertiary care center. METHODS: Children ages 0 to 21 years with SSD (N = 190) who underwent computerized tomography (CT) and/or magnetic resonance imaging (MRI) were included. Diagnostic criteria for SSD included unilateral severe-to-profound sensorineural hearing loss with normal hearing sensitivity in the contralateral ear. Diagnostic criteria for CND included neuroradiologist report of an "aplastic or hypoplastic nerve" on MRI or a "stenotic cochlear aperture" on CT. RESULTS: The prevalence of CND was 42% for children with CT only, 76% for children with MRI only, and 63% for children with both MRI and CT. Of the children with MRI and CT, there was a 90% concordance across imaging modalities. About 36% of children with SSD had hearing devices that routed sound to the normal hearing ear (ie, bone conduction hearing device/contralateral routing of signal), while only 3% received a cochlear implant. Approximately 40% did not have a hearing device. Hearing device wear time averaged 2.9 hours per day and did not differ based on cochlear nerve status. CONCLUSION: There is a high prevalence of CND in children with SSD. Cochlear nerve status should be confirmed via MRI in children with SSD. The limited implementation and use of hearing devices observed for children with SSD reinforce the need for increased support for early and continuous intervention.

Updates in Eustachian Tube Dysfunction.

Eustachian tube dysfunction (ETD) is a common middle ear disorder in children that can have a significant impact on the quality of life. This review aims to provide an updated understanding of ETD and its clinical management. We will discuss the pathophysiology and diagnosis of ETD, as well as the medical and surgical treatment of ETD. We will also review studies of both adults and children with ETD, although special attention will be paid to children with ETD.

Artificial intelligence and tele-otoscopy: A window into the future of pediatric otology.

Telehealth in otolaryngology is gaining popularity as a potential tool for increased access for rural populations, decreased specialist wait times, and overall savings to the healthcare system. The adoption of telehealth has been dramatically increased by the COVID-19 pandemic limiting patients' physical access to hospitals and clinics. One of the key challenges to telehealth in general otolaryngology and otology specifically is the limited physical examination possible on the ear canal and middle ear. This is compounded in pediatric populations who commonly present with middle ear pathologies which can be challenging to diagnose even in the clinic. To address this need, various otoscopes have been designed to allow patients, their parents, or primary care providers to image the tympanic membrane and middle ear, and send data to otolaryngologists for review. Furthermore, the ability of these devices to capture images in digital format has opened the possibility of using artificial intelligence for quick and reliable diagnostic workup. In this manuscript, we provide a concise review of the literature regarding the efficacy of remote otoscopy, as well as recent efforts on the use of artificial intelligence in aiding otologic diagnoses.

Infectious Complications Following Cochlear Implant: Risk Factors, Natural History, and Management Patterns.

OBJECTIVE: To describe the natural history, detail the treatment patterns, and identify the risk factors for cochlear implant (CI) infections in a large US cohort. STUDY DESIGN: Retrospective study based on insurance claims. SETTING: Optum Data Mart database: 6101 patients who received CIs from 2003 to 2019. METHODS: Infections, treatments patterns, and timelines were described. A multivariable logistic regression model was used to assess the association between postoperative oral antibiotics and CI infection. RESULTS: The cohort includes 4736 (77.6%) adults and 1365 (22.4%) children. Between adult and pediatric patients, rates of CI infection (5.1% vs 4.5%, P = .18) and explantation (1.2% vs 0.8%, P = .11) were not significantly different. Infections typically occurred within 5 months of surgery. Children were diagnosed with CI infection earlier than adults (median difference, -1.5 months; P = .001). Postoperative oral antibiotic supply was not associated with lower risk of CI infection in either children or adults. However, among adults, otitis media was associated with higher odds of CI infection (odds ratio, 1.41; P < .001), while higher income was associated with lower odds of CI infection (odds ratio, 0.71; P = .03). CONCLUSIONS: Postoperative oral antibiotics were not associated with lower risk of infection or interventions. Otitis media episodes and lower income were associated with increased risk of infection among adults as well as intervention overall. Infection typically presented within the first 6 months after surgery, with children presenting earlier than adults. Overall, our findings serve as a resource for providers to consider in their care of patients with CIs.

MRI Correlates of Ototoxicity in the Auditory Pathway in Children Treated for Medulloblastoma.

OBJECTIVE: To assess diffusion and perfusion changes of the auditory pathway in pediatric medulloblastoma patients exposed to ototoxic therapies. STUDY DESIGN: Retrospective cohort study. SETTING: A single academic tertiary children's hospital. PATIENTS: Twenty pediatric medulloblastoma patients (13 men; mean age 12.0 ±â€Š4.8 yr) treated with platinum-based chemotherapy with or without radiation and 18 age-and-sex matched controls were included. Ototoxicity scores were determined using Chang Ototoxicity Grading Scale. INTERVENTIONS: Three Tesla magnetic resonance was used for diffusion tensor and arterial spin labeling perfusion imaging. MAIN OUTCOME MEASURES: Quantitative diffusion tensor metrics were extracted from the Heschl's gyrus, auditory radiation, and inferior colliculus. Arterial spin labeling perfusion of the Heschl's gyrus was also examined. RESULTS: Nine patients had clinically significant hearing loss, or Chang grades more than or equal to 2a; 11 patients had mild/no hearing loss, or Chang grades less than 2a. The clinically significant hearing loss group showed reduced mean diffusivity in the Heschl's gyrus (p = 0.018) and auditory radiation (p = 0.037), and decreased perfusion in the Heschl's gyrus (p = 0.001). Mild/no hearing loss group showed reduced mean diffusivity (p = 0.036) in Heschl's gyrus only, with a decrease in perfusion (p = 0.008). There were no differences between groups in the inferior colliculus. There was no difference in fractional anisotropy between patients exposed to ototoxic therapies and controls. CONCLUSIONS: Patients exposed to ototoxic therapies demonstrated microstructural and physiological alteration of the auditory pathway. The present study shows proof-of-concept use of diffusion tensor imaging to gauge ototoxicity along the auditory pathway. Future larger cohort studies are needed to assess significance of changes in diffusion tensor imaging longitudinally, and the relationship between these changes and hearing loss severity and longitudinal changes of the developing auditory white matter.

Trends and Healthcare Use Following Different Cholesteatoma Surgery Types in a National Cohort, 2003-2019.

OBJECTIVE: To describe national trends in cholesteatoma management. STUDY DESIGN AND SETTING: Retrospective analysis Optum Clinformatics® Database from 2003 to 2019. PATIENTS: 16,179 unique adult and pediatric patients who received cholesteatoma surgery. INTERVENTIONS AND MAIN OUTCOME MEASURES: Patients were categorized into three groups by initial surgical modality: canal wall down (CWD), canal wall up (CWU), and tympanoplasty without mastoidectomy (TnoM). Three major comparisons between groups were performed: 1) temporal trends, 2) clinical and sociodemographic determinants, and 3) healthcare use in terms of total costs and incidence of postoperative imaging and subsequent surgery. RESULTS: Overall, 23.2% received initial CWD surgery, 44.3% CWU, and 32.5% TnoM. 1) The incidence of initial CWD surgery decreased (odds ratios [OR] = 0.98, 95% confidence intervals [CI] [0.97,0.99]), while CWU increased (OR = 1.02, 95% CI [1.01,1.03]), and TnoM remained stable over the study period (OR = 0.99, 95% CI [0.98,1.00]). 2) Relative to CWU, TnoM surgery was less likely in adults, patients with prior complications, and non-White patients, while being more likely in patients with higher household income. CWD was more likely than CWU in adults, patients with prior complications, and non-White patients, while income had no effect. 3) Postoperative costs for CWU and CWD were similar. In 2 years following initial surgery, postoperative imaging and/or subsequent surgery was performed in 45.48% of CWD, 57.42% of CWU, and 41.62% of TnoM patients. CONCLUSIONS: Incidence of initial CWD surgery decreased and social disparities in cholesteatoma management were observed. Postoperative imaging or second-look surgery were performed in less than 60% of patients with initial CWU surgery and over 40% of patients with initial CWD.

Shortwave infrared otoscopy for diagnosis of middle ear effusions: a machine-learning-based approach.

Otitis media, a common disease marked by the presence of fluid within the middle ear space, imparts a significant global health and economic burden. Identifying an effusion through the tympanic membrane is critical to diagnostic success but remains challenging due to the inherent limitations of visible light otoscopy and user interpretation. Here we describe a powerful diagnostic approach to otitis media utilizing advancements in otoscopy and machine learning. We developed an otoscope that visualizes middle ear structures and fluid in the shortwave infrared region, holding several advantages over traditional approaches. Images were captured in vivo and then processed by a novel machine learning based algorithm. The model predicts the presence of effusions with greater accuracy than current techniques, offering specificity and sensitivity over 90%. This platform has the potential to reduce costs and resources associated with otitis media, especially as improvements are made in shortwave imaging and machine learning.

The risk of ergonomic injury across surgical specialties.

Lack of ergonomic training and poor ergonomic habits during the operation leads to musculoskeletal pain and affects the surgeon's life outside of work. The objective of the study was to evaluate the severity of ergonomic hazards in the surgical profession across a wide range of surgical subspecialties. We conducted intraoperative observations using Rapid Entire Body Assessment (REBA) score system to identify ergonomic hazards. Additionally, each of the ten surgical subspecialty departments were sent an optional 14 question survey which evaluated ergonomic practice, environmental infrastructure, and prior ergonomic training or education. A total of 91 surgeons received intraoperative observation and were evaluated on the REBA scale with a minimum score of 0 (low ergonomic risk <3) and a maximum score of 10 (high ergonomic risk 8-10). And a total of 389 surgeons received the survey and 167 (43%) surgeons responded. Of the respondents, 69.7% reported suffering from musculoskeletal pain. Furthermore, 54.9% of the surgeons reported suffering from the highest level of pain when standing during surgery, while only 14.4% experienced pain when sitting. Importantly, 47.7% stated the pain impacted their work, while 59.5% reported pain affecting quality of life outside of work. Only 23.8% of surgeons had any prior ergonomic education. Both our subjective and objective data suggest that pain and disability induced by poor ergonomics are widespread among the surgical community and confirm that surgeons rarely receive ergonomic training. Intraoperative observational findings identified that the majority of observed surgeons displayed poor posture, particularly a poor cervical angle and use of ergonomic setups, both of which increase ergonomic risk hazards. This data supports the need for a comprehensive ergonomic interventional program for the surgical team and offers potential targets for future intervention.

Modeling human adaptive immune responses with tonsil organoids.

Most of what we know about adaptive immunity has come from inbred mouse studies, using methods that are often difficult or impossible to confirm in humans. In addition, vaccine responses in mice are often poorly predictive of responses to those same vaccines in humans. Here we use human tonsils, readily available lymphoid organs, to develop a functional organotypic system that recapitulates key germinal center features in vitro, including the production of antigen-specific antibodies, somatic hypermutation and affinity maturation, plasmablast differentiation and class-switch recombination. We use this system to define the essential cellular components necessary to produce an influenza vaccine response. We also show that it can be used to evaluate humoral immune responses to two priming antigens, rabies vaccine and an adenovirus-based severe acute respiratory syndrome coronavirus 2 vaccine, and to assess the effects of different adjuvants. This system should prove useful for studying critical mechanisms underlying adaptive immunity in much greater depth than previously possible and to rapidly test vaccine candidates and adjuvants in an entirely human system.

Use of Diagnostic Testing and Intervention for Sensorineural Hearing Loss in US Children From 2008 to 2018.

Importance: Early detection and intervention of pediatric hearing loss is critical for language development and academic achievement. However, variations in the diagnostic workup and management of pediatric sensorineural hearing loss (SNHL) exist. Objective: To identify patient and clinician factors that are associated with variation in practice on a national level. Design, Setting, and Participants: This cross-sectional study used the Optum claims database to identify 53 711 unique children with SNHL between January 1, 2008, and December 31, 2018. Main Outcomes and Measures: National use rates and mean costs for diagnostic modalities (electrocardiogram, cytomegalovirus testing, magnetic resonance imaging, computed tomography, and genetic testing) and interventions (speech-language pathology, billed hearing aid services, and cochlear implant surgery) were reported. The associations of age, sex, SNHL laterality, clinician type, race/ethnicity, and household income with diagnostic workup and intervention use were measured in multivariable analyses. Results: Of 53 711 patients, 23 735 (44.2%) were girls, 2934 (5.5%) were Asian, 3797 (7.1%) were Black, 5626 (10.5%) were Hispanic, 33 441 (62.3%) were White, and the mean (SD) age was 7.3 (5.3) years. Of all patients, 32 200 (60.0%) were seen by general otolaryngologists, while 7573 (14.10%) were seen by pediatric otolaryngologists. Diagnostic workup was received by 14 647 patients (27.3%), while 13 482 (25.1%) received intervention. Use of genetic testing increased (odds ratio, 1.22 per year; 95% CI, 1.20-1.24), whereas use of computed tomography decreased (odds ratio, 0.93 per year; 95% CI, 0.92-0.94) during the study period. After adjusting for relevant covariables, children who were seen by pediatric otolaryngologists and geneticists had the highest odds of receiving workup and intervention. Additionally, racial/ethnic and economic disparities were observed in the use of most modalities of diagnostic workup and intervention for pediatric SNHL. Conclusions and Relevance: This cross-sectional study identified factors associated with disparities in the diagnostic workup and intervention of pediatric SNHL, thus highlighting the need for increased education and standardization in the management of this common sensory disorder.

Total Synthesis of (+)-Petromyroxol, (-)-iso-Petromyroxol, and Possible Diastereomers.

The total synthesis of (+)-petromyroxol (1) and its seven diastereomers including the (-)-iso-petromyroxol (2) is described. The employed strategy involves the use of easily available C5-epimeric epoxides 5 and 5' and nonselective anomeric C1-allylation, proceeding with or without inversion at C2, thereby giving the possibility of synthesizing all possible diastereomers. Extensive two-dimensional (2D) NMR analyses of all eight diastereomers have been carried out to assign the chemical shifts of the central carbons and the corresponding attached hydrogens and to learn how the C/H-chemical shifts of the tetrahydrofuran ring were influenced by the adjacent centers.