Functional mechanotransduction is required for cisplatin-induced hair cell death in the zebrafish lateral line.

Cisplatin, one of the most commonly used anticancer drugs, is known to cause inner ear hair cell damage and hearing loss. Despite much investigation into mechanisms of cisplatin-induced hair cell death, little is known about the mechanism whereby cisplatin is selectively toxic to hair cells. Using hair cells of the zebrafish lateral line, we found that chemical inhibition of mechanotransduction with quinine and EGTA protected against cisplatin-induced hair cell death. Furthermore, we found that the zebrafish mutants mariner (myo7aa) and sputnik (cad23) that lack functional mechanotransduction were resistant to cisplatin-induced hair cell death. Using a fluorescent analog of cisplatin, we found that chemical or genetic inhibition of mechanotransduction prevented its uptake. These findings demonstrate that cisplatin-induced hair cell death is dependent on functional mechanotransduction in the zebrafish lateral line.

In vivo screening for toxicity-modulating drug interactions identifies antagonism that protects against ototoxicity in zebrafish.

Introduction: Ototoxicity is a debilitating side effect of over 150 medications with diverse mechanisms of action, many of which could be taken concurrently to treat multiple conditions. Approaches for preclinical evaluation of drug-drug interactions that might impact ototoxicity would facilitate design of safer multi-drug regimens and mitigate unsafe polypharmacy by flagging combinations that potentially cause adverse interactions for monitoring. They may also identify protective agents that antagonize ototoxic injury. Methods: To address this need, we have developed a novel workflow that we call Parallelized Evaluation of Protection and Injury for Toxicity Assessment (PEPITA), which empowers high-throughput, semi-automated quantification of ototoxicity and otoprotection in zebrafish larvae via microscopy. We used PEPITA and confocal microscopy to characterize in vivo the consequences of drug-drug interactions on ototoxic drug uptake and cellular damage of zebrafish lateral line hair cells. Results and discussion: By applying PEPITA to measure ototoxic drug interaction outcomes, we discovered antagonistic interactions between macrolide and aminoglycoside antibiotics that confer protection against aminoglycoside-induced damage to lateral line hair cells in zebrafish larvae. Co-administration of either azithromycin or erythromycin in zebrafish protected against damage from a broad panel of aminoglycosides, at least in part via inhibiting drug uptake into hair cells via a mechanism independent from hair cell mechanotransduction. Conversely, combining macrolides with aminoglycosides in bacterial inhibition assays does not show antagonism of antimicrobial efficacy. The proof-of-concept otoprotective antagonism suggests that combinatorial interventions can potentially be developed to protect against other forms of toxicity without hindering on-target drug efficacy.

Fish in a Dish: Drug Discovery for Hearing Habilitation.

The majority of hearing loss is caused by the permanent loss of inner ear hair cells. The identification of drugs that modulate the susceptibility to hair cell loss or spur their regeneration is often hampered by the difficulties of assaying for such complex phenomena in mammalian models. The zebrafish has emerged as a powerful animal model for chemical screening in many contexts. Several characteristics of the zebrafish, such as its small size and external location of sensory hair cells, uniquely position it as an ideal model organism for the study of hair cell toxicity, protection, and regeneration. We have used this model to screen for drugs that affect each of these aspects of hair cell biology and have identified compounds that affect each of these processes. The identification of such drugs and drug-like compounds holds promise in the future ability to stem hearing loss in the human population.

Sensitivity to Deaf Culture Among Otolaryngology and Audiology Trainees.

OBJECTIVE: The Deaf community is an ethnolinguistic minority group. Low sensitivity to Deaf culture contributes to health disparities among Deaf patients. This study determines the level of sensitivity to Deaf culture among otolaryngology-head and neck surgery (OHNS) and audiology trainees. METHODS: Cross-sectional survey study of OHNS and audiology trainees from 10 large US institutions. Trainees were queried on their exposure to and comfort with Deaf patients and their education on, attitude toward, and awareness and knowledge of Deaf culture. Sensitivity to Deaf culture was operationalized as awareness and knowledge of Deaf culture. These were assessed using a 35-item instrument that was previously developed using a d/Deaf community-based participatory approach to research. We used T-tests to compare the sample to previous samples of medical students with training in Deaf culture (MS-TDCs) and general practitioners (GPs). RESULTS: There were 91 completed surveys (response rate 44.5%). Almost all were aware of Deaf culture (97.8%). The mean knowledge score was 55.0% (standard deviation (SD) 13.4%), which was significantly higher than that for GPs at 43.0% (SD 15.0%) (95% confidence interval 8.1%, 15.8%, P < .0001) but significantly lower than that for MS-TDCs at 69.0% (SD 13.0%)(CI -20.3%, -7.6%, P < .0001). Knowledge scores were comparable for OHNS and audiology trainees (P = .09). CONCLUSION: This sample of OHNS and audiology trainees was more sensitive to Deaf culture than GPs but less sensitive than MS-TDCs. Developing specialty-specific education may be warranted. LEVEL OF EVIDENCE: 4.

Association of Genetic Diagnoses for Childhood-Onset Hearing Loss With Cochlear Implant Outcomes.

Importance: In the US, most childhood-onset bilateral sensorineural hearing loss is genetic, with more than 120 genes and thousands of different alleles known. Primary treatments are hearing aids and cochlear implants. Genetic diagnosis can inform progression of hearing loss, indicate potential syndromic features, and suggest best timing for individualized treatment. Objective: To identify the genetic causes of childhood-onset hearing loss and characterize severity, progression, and cochlear implant success associated with genotype in a single large clinical cohort. Design, Setting, and Participants: This cross-sectional analysis (genomics) and retrospective cohort analysis (audiological measures) were conducted from 2019 to 2022 at the otolaryngology and audiology clinics of Seattle Children's Hospital and the University of Washington and included 449 children from 406 families with bilateral sensorineural hearing loss with an onset younger than 18 years. Data were analyzed between January and June 2022. Main Outcomes and Measures: Genetic diagnoses based on genomic sequencing and structural variant analysis of the DNA of participants; severity and progression of hearing loss as measured by audiologic testing; and cochlear implant success as measured by pediatric and adult speech perception tests. Hearing thresholds and speech perception scores were evaluated with respect to age at implant, months since implant, and genotype using a multivariate analysis of variance and covariance. Results: Of 406 participants, 208 (51%) were female, 17 (4%) were African/African American, 32 (8%) were East Asian, 219 (54%) were European, 53 (13%) were Latino/Admixed American, and 16 (4%) were South Asian. Genomic analysis yielded genetic diagnoses for 210 of 406 families (52%), including 55 of 82 multiplex families (67%) and 155 of 324 singleton families (48%). Rates of genetic diagnosis were similar for children of all ancestries. Causal variants occurred in 43 different genes, with each child (with 1 exception) having causative variant(s) in only 1 gene. Hearing loss severity, affected frequencies, and progression varied by gene and, for some genes, by genotype within gene. For children with causative mutations in MYO6, OTOA, SLC26A4, TMPRSS3, or severe loss-of-function variants in GJB2, hearing loss was progressive, with losses of more than 10 dB per decade. For all children with cochlear implants, outcomes of adult speech perception tests were greater than preimplanted levels. Yet the degree of success varied substantially by genotype. Adjusting for age at implant and interval since implant, speech perception was highest for children with hearing loss due to MITF or TMPRSS3. Conclusions and Relevance: The results of this cross-sectional study suggest that genetic diagnosis is now sufficiently advanced to enable its integration into precision medical care for childhood-onset hearing loss.

In vivo screening for toxicity-modulating drug interactions identifies antagonism that protects against ototoxicity in zebrafish.

Ototoxicity is a debilitating side effect of over 150 medications with diverse mechanisms of action, many of which could be taken concurrently to treat multiple conditions. Approaches for preclinical evaluation of drug interactions that might impact ototoxicity would facilitate design of safer multi-drug regimens and mitigate unsafe polypharmacy by flagging combinations that potentially cause adverse interactions for monitoring. They may also identify protective agents that antagonize ototoxic injury. To address this need, we have developed a novel workflow that we call Parallelized Evaluation of Protection and Injury for Toxicity Assessment (PEPITA), which empowers high-throughput, semi-automated quantification of ototoxicity and otoprotection in zebrafish larvae. By applying PEPITA to characterize ototoxic drug interaction outcomes, we have discovered antagonistic interactions between macrolide and aminoglycoside antibiotics that confer protection against aminoglycoside-induced damage to lateral line hair cells in zebrafish larvae. Co-administration of either azithromycin or erythromycin in zebrafish protected against damage from a broad panel of aminoglycosides, at least in part via inhibiting drug uptake into hair cells via a mechanism independent from hair cell mechanotransduction. Conversely, combining macrolides with aminoglycosides in bacterial inhibition assays does not show antagonism of antimicrobial efficacy. The proof-of-concept otoprotective antagonism suggests that combinatorial interventions can potentially be developed to protect against other forms of toxicity without hindering on-target drug efficacy.

Educational Environments and Secondary School Outcomes Among Students Who Are D/deaf and Hard of Hearing in Special Education.

PURPOSE: The purpose of this study is to provide updated national estimates on the annual number, educational environments, and secondary school outcomes of students who are D/deaf and hard of hearing (D/HH) receiving special education (SpEd) and related services in the United States. METHOD: We performed a retrospective cross-sectional descriptive analysis of Individuals with Disabilities Education Act, Part B, Section 618 data from 2012 to 2018. Participants included students 6-21 years old in SpEd with "hearing impairment" reported as their primary disability. The general population of students in secondary school served as a comparator, via Current Population Survey data. We described the annual number of students (a) overall, (b) by educational environment, and (c) by reason for exiting SpEd, including the proportion graduating from and dropping out of secondary school. We described variation over time. RESULTS: The median annual number of students was 67,655, with minimal variation by year. The proportion in general education (GenEd) for ≥ 80% of the day increased by 4.2% over 6 years from 57.8% to 62.0%, whereas the proportions in GenEd for < 40% and 40%-79% of the day decreased by 1.6% and 1.3%, respectively. Proportions in the remainder of the environments changed < 1.0% each. Of exiters, 86.8% of students graduated, whereas 3.9% dropped out, compared to a dropout rate of 5.0% in the general population. CONCLUSION: From 2012 to 2018, students who are D/HH receiving SpEd in the United States have spent increasingly more time in GenEd, most graduated from high school, and few dropped out, with dropout patterns appearing similar to the general population.

Impact of Eliminating Local Anesthesia on Immediate Postoperative Analgesia in Pediatric Ambulatory Adenotonsillectomy.

Our goal was to standardize intraoperative analgesic regimens for pediatric ambulatory tonsillectomy by eliminating local anesthetic use and to determine its impact on postoperative pain measures, while controlling for other factors. METHODS: We assembled a quality improvement team at an ambulatory surgery center. They introduced a standardized anesthetic protocol, involving American Society of Anesthesiologists Classification 1 and 2 patients undergoing adenotonsillectomy. Local anesthesia elimination was the project's single intervention. We collected pre-intervention data (79 cases) from July 5 to September 17, 2019 and post-intervention data (59 cases) from September 25 to December 17, 2019. The intervention requested that surgeons eliminate the use of local anesthetics. The following outcomes measures were evaluated using statistical process control charts and Shewhart's theory of variation: (1) maximum pain score in the post-anesthesia care unit, (2) total post-anesthesia care unit minutes, and (3) postoperative opioid rescue rate. RESULTS: No special cause variation signal was detected in any of the measures following the intervention. CONCLUSIONS: Our data suggest that eliminating intraoperative local anesthetic use does not worsen postoperative pain control at our facility. The intervention eliminated the added expenses and possible risks associated with local anesthetic use. This series is unique in its standardization of anesthetic regimen in a high-volume ambulatory surgery center with the exception of local anesthesia practices. The study results may impact the standardized clinical protocol for pediatric ambulatory adenotonsillectomy at our institution and may hold relevance for other centers.

Defining Essential Services for Deaf and Hard of Hearing Children during the COVID-19 Pandemic.

COVID-19 is a rapidly growing global pandemic caused by a novel coronavirus. With no vaccine or definitive treatment, public health authorities have recommended a strategy of "social distancing," reducing individual interaction, canceling elective procedures, and limiting nonessential services. Health care providers must determine what procedures are considered "elective," balancing risk of treatment delays with that of coronavirus exposure to patient, family, and providers. Given critical periods for language development and the long-term impact of auditory deprivation, some audiologic and otologic services should be considered essential. In this article, we describe the experience of a quaternary referral pediatric hospital in Seattle, the epicenter of COVID-19 in the United States, and share strategies for risk minimization employed by Seattle Children's Hospital. We hope that this work can be a reference for other centers continuing care for children who are deaf and hard of hearing during the COVID-19 and future resource-limiting crises.

Reliability of Measuring Insertion Depth in Cochlear Implanted Infants and Children Using Cochlear View Radiography.

OBJECTIVES: Cochlear implant depth of insertion affects audiologic outcomes and can be measured in adults using plain films obtained in the "cochlear view." The objective of this study was to assess interrater and intrarater reliability of measuring depth of insertion using cochlear view radiography. STUDY DESIGN: Prospective, observational. SETTING: Tertiary referral pediatric hospital. SUBJECTS AND METHODS: Patients aged 11 months to 20 years (median, 4 years; interquartile range [IQR], 1-8 years) undergoing cochlear implantation at our institution were studied over 1 year. Children underwent cochlear view imaging on postoperative day 1. Films were deidentified and 1 image per ear was selected. Two cochlear implant surgeons and 2 radiologists evaluated each image and determined angular depth of insertion. Images were re-reviewed 6 weeks later by all raters. Inter- and intrarater reliability were calculated with intraclass correlation coefficients (ICCs). RESULTS: Fifty-seven ears were imaged from 42 children. Forty-nine ears (86%) had successful cochlear view x-rays. Median angular depth of insertion was 381° (minimum, 272°; maximum, 450°; IQR, 360°-395°) during the first round of measurement. Measurements of the same images reviewed 6 weeks later showed median depth of insertion of 382° (minimum, 272°; maximum, 449°; IQR, 360°-397°). Interrater and intrarater reliability ICCs ranged between 0.81 and 0.96, indicating excellent reliability. CONCLUSIONS: Postoperative cochlear view radiography is a reliable tool for measurement of cochlear implant depth of insertion in infants and children. Further studies are needed to determine reliability of intraoperatively obtained cochlear view radiographs in this population.

Pediatric Otolaryngology Divisional and Institutional Preparatory Response at Seattle Children's Hospital after COVID-19 Regional Exposure.

Coronavirus disease 2019 (COVID-19) is a novel coronavirus resulting in high mortality in the adult population but low mortality in the pediatric population. The role children and adolescents play in COVID-19 transmission is unclear, and it is possible that healthy pediatric patients serve as a reservoir for the virus. This article serves as a summary of a single pediatric institution's response to COVID-19 with the goal of protecting both patients and health care providers while providing ongoing care to critically ill patients who require urgent interventions. A significant limitation of this commentary is that it reflects a single institution's joint effort at a moment in time but does not take into consideration future circumstances that could change practice patterns. We still hope dissemination of our overall response at this moment, approximately 8 weeks after our region's first adult case, may benefit other pediatric institutions preparing for COVID-19.

Using the zebrafish lateral line to screen for ototoxicity.

The zebrafish is a valuable model for studying hair cell development, structure, genetics, and behavior. Zebrafish and other aquatic vertebrates have hair cells on their body surface organized into a sensory system called the lateral line. These hair cells are highly accessible and easily visualized using fluorescent dyes. Morphological and functional similarities to mammalian hair cells of the inner ear make the zebrafish a powerful preparation for studying hair cell toxicity. The ototoxic potential of drugs has historically been uncovered by anecdotal reports that have led to more formal investigation. Currently, no standard screen for ototoxicity exists in drug development. Thus, for the vast majority of Food and Drug Association (FDA)-approved drugs, the ototoxic potential remains unknown. In this study, we used 5-day-old zebrafish larvae to screen a library of 1,040 FDA-approved drugs and bioactives (NINDS Custom Collection II) for ototoxic effects in hair cells of the lateral line. Hair cell nuclei were selectively labeled using a fluorescent vital dye. For the initial screen, fish were exposed to drugs from the library at a 100-muM concentration for 1 h in 96-well tissue culture plates. Hair cell viability was assessed in vivo using fluorescence microscopy. One thousand forty drugs were rapidly screened for ototoxic effects. Seven known ototoxic drugs included in the library, including neomycin and cisplatin, were positively identified using these methods, as proof of concept. Fourteen compounds without previously known ototoxicity were discovered to be selectively toxic to hair cells. Dose-response curves for all 21 ototoxic compounds were determined by quantifying hair cell survival as a function of drug concentration. Dose-response relationships in the mammalian inner ear for two of the compounds without known ototoxicity, pentamidine isethionate and propantheline bromide, were then examined using in vitro preparations of the adult mouse utricle. Significant dose-dependent hair cell loss in the mouse utricle was demonstrated for both compounds. This study represents an important step in validating the use of the zebrafish lateral line as a screening tool for the identification of potentially ototoxic drugs.

Comparison of MRI in pediatric cochlear implant recipients with and without retained magnet.

OBJECTIVE: To report and compare medical, radiological, and audiological outcomes in pediatric cochlear implant recipients who underwent 1.5 and 3 Tesla strength MRI with and without retained magnet. METHODS: Retrospective chart review at a tertiary care pediatric hospital and review of literature. Patients were identified via electronic medical records database search and were included if they had MRI after cochlear implant. RESULTS: Of twelve instances of MRI in pediatric cochlear implant recipients at our institution, two minor complications and one major complication were recorded. The rate of complication was equal between patients who underwent MRI with and without retained magnet. All minor complications resulted from MRI with retained magnet whereas the only major complication resulted from magnet removal. Two novel complications are reported, including: magnet removal resulting in silastic tear necessitating reimplantation and magnet dislocation with spontaneous reduction. Magnet removal significantly decreased the size of artifact, but did not alter the diagnostic utility of the MRI. While audiological measures varied chronologically from MRI scans, they did not appear to be appreciably altered by MRI. CONCLUSION: MRI with and without magnet retention appear to carry risks of both major and minor complications. For the regions of interest for each scan, MRI quality was not appreciably altered by magnet status. Audiological measures appear unaffected by magnet status during MRI however, this may reflect natural variation.

Unilateral Hearing Loss in Youth: Development of Candidate Items for a Condition-Specific Validated Instrument.

OBJECTIVE: This study interviewed youth with unilateral hearing, utilizing their responses to generate candidate items for a condition-specific patient-reported instrument. STUDY DESIGN: Mixed methods, cross-sectional. SETTING: Tertiary care children's hospital. PARTICIPANTS AND METHODS: Youth with unilateral hearing loss and normal hearing in the contralateral ear were identified and recruited for participation through query of an audiometric database and through hearing loss clinics. Interviews with the youth were qualitatively analyzed to identify common themes and generate items related to functional impact. A multi-institutional expert panel reviewed items with prespecified item selection criteria. Participants rated items for impact on daily life. For preliminary criterion validity assessment, statistical analyses explored correlations between functional scores and type and severity of hearing loss. RESULTS: Thirty-nine youth aged 9 to 18 years with unilateral hearing loss participated; 31% used a hearing device. Fifteen youth participated in interviews; thematic analysis, item crafting, and expert panel item review resulted in 41 items. Twenty-six youth responded to the items, reporting low functional scores in the domains of sound localization, ear positioning, and noise environment. They reported better levels of function in carrying out group conversations, focusing on schoolwork, and feeling safe during activities. Multivariate linear regression found that youth scored 0.4 points (or approximately 8%) lower on the functional impact scale with every 20-dB HL increase in pure tone average in the abnormal ear. CONCLUSION: Youth with unilateral hearing loss report functional impact, particularly related to sound localization, ear positioning, and noise environment; therefore, they may benefit from a condition-specific functional assessment instrument.

Cisplatin-induced hair cell loss in zebrafish (Danio rerio) lateral line.

We have used time-lapse imaging to study cisplatin-induced hair cell death in lateral line neuromasts of zebrafish larvae in vivo. We found that cisplatin-induced hair cell death occurred much more slowly than had been shown to occur in aminoglycoside-induced hair cell death. By prelabeling hair cells with FM1-43FX, and assessing hair cell damage, it was established that cisplatin causes hair cell loss in the lateral line in a dose-dependent fashion. The kinetics of hair cell loss during exposure to different concentrations of cisplatin was also assessed and it was found that the onset of hair cell loss correlated with the accumulated dose of cisplatin. These data demonstrate the feasibility and repeatability of cisplatin damage protocols in the zebrafish lateral line and set the stage for future evaluations of modulation of cisplatin-induced hair cell death.

Mitochondrial calcium uptake underlies ROS generation during aminoglycoside-induced hair cell death.

Exposure to aminoglycoside antibiotics can lead to the generation of toxic levels of reactive oxygen species (ROS) within mechanosensory hair cells of the inner ear that have been implicated in hearing and balance disorders. Better understanding of the origin of aminoglycoside-induced ROS could focus the development of therapies aimed at preventing this event. In this work, we used the zebrafish lateral line system to monitor the dynamic behavior of mitochondrial and cytoplasmic oxidation occurring within the same dying hair cell following exposure to aminoglycosides. The increased oxidation observed in both mitochondria and cytoplasm of dying hair cells was highly correlated with mitochondrial calcium uptake. Application of the mitochondrial uniporter inhibitor Ru360 reduced mitochondrial and cytoplasmic oxidation, suggesting that mitochondrial calcium drives ROS generation during aminoglycoside-induced hair cell death. Furthermore, targeting mitochondria with free radical scavengers conferred superior protection against aminoglycoside exposure compared with identical, untargeted scavengers. Our findings suggest that targeted therapies aimed at preventing mitochondrial oxidation have therapeutic potential to ameliorate the toxic effects of aminoglycoside exposure.

Identification of small molecule inhibitors of cisplatin-induced hair cell death: results of a 10,000 compound screen in the zebrafish lateral line.

HYPOTHESIS: The zebrafish lateral line can be used to identify small molecules that protect against cisplatin-induced hair cell death. BACKGROUND: Cisplatin is a commonly used chemotherapeutic agent, which causes hearing loss by damaging hair cells of the inner ear. There are currently no FDA-approved pharmacologic strategies for preventing this side effect. The zebrafish lateral line has been used successfully in the past to study hair cell death and protection. METHODS: In this study, we used the zebrafish lateral line to screen a library of 10,000 small molecules for protection against cisplatin-induced hair cell death. Dose-response relationships for identified protectants were determined by quantifying hair cell protection. The effect of each protectant on uptake of a fluorescent cisplatin analog was also quantified. RESULTS: From this screen, we identified 2 compounds exhibiting dose-dependent protection: cisplatin hair cell protectant 1 and 2 (CHCP1 and 2). CHCP1 reduced the uptake of a fluorescent cisplatin analog, suggesting its protective effects may be due to decreased cisplatin uptake. CHCP2 did not affect uptake, which suggests an intracellular mechanism of action. Evaluation of analogs of CHCP2 revealed 3 additional compounds that significantly reduced cisplatin-induced hair cell death, although none exceed the effectiveness or potency of the parent compound. CONCLUSION: The zebrafish lateral line was used to identify 2 small molecules that protected against cisplatin-induced hair cell death.

Canertinib induces ototoxicity in three preclinical models.

Neuregulin-1 (NRG1) ligand and its epidermal growth factor receptor (EGFR)/ERBB family regulate normal cellular proliferation and differentiation in many tissues including the cochlea. Aberrant NRG1 and ERBB signaling cause significant hearing impairment in mice. Dysregulation of the same signaling pathway in humans is involved in certain types of cancers such as breast cancer or non-small cell lung cancer (NSCLC). A new irreversible pan-ERBB inhibitor, canertinib, has been tested in clinical trials for the treatment of refractory NSCLC. Its possible ototoxicity was unknown. In this study, a significant dose-dependent canertinib ototoxicity was observed in a zebrafish model. Canertinib ototoxicity was further confirmed in two mouse models with different genetic backgrounds. The data strongly suggested an evolutionally preserved ERBB molecular mechanism underlying canertinib ototoxicity. Thus, these results imply that clinical monitoring of hearing loss should be considered for clinical testing of canertinib or other pan-ERBB inhibitors.

Upper aerodigestive magnetic foreign bodies in children.

OBJECTIVES/HYPOTHESIS: Small, powerful magnets are increasingly available in toys and other products, and are responsible for increasing numbers of foreign body injuries in children. Small, spherical, neodymium magnets available since 2008 are of particular concern. We aimed to identify all cases of upper aerodigestive foreign bodies at our institution over 15.5 years of study. STUDY DESIGN: Case series including all patients treated at an urban, tertiary care children's hospital who had upper aerodigestive magnetic foreign bodies, from January 1, 1998 through April 30, 2013. METHODS: We manually reviewed 7,049 patient records abstracted from billing data to identify all patients 0 to 20 years of age who had upper aerodigestive magnetic foreign bodies. RESULTS: We identified four cases of upper aerodigestive magnetic foreign bodies, one involving the hypopharynx, and three involving the upper esophagus. Three occurred in 2010 or later. Two cases involve the ingestion of multiple, spherical, neodymium magnets recently marketed as desktop toys. In both of these cases, there was a rapid development of mucosal injury at the site of attraction between two magnets. CONCLUSIONS: As small, powerful magnets become more ubiquitous, pediatric magnet foreign body injuries are increasing. Although most are gastrointestinal, we identified four recent cases involving the upper aerodigestive tract. Multiple magnets lodged in the hypopharynx or esophagus can rapidly cause pressure necrosis of mucosal tissues, and merit prompt management. Education regarding magnet safety and improved magnet safety standards are needed to reduce the risk of these injuries. LEVEL OF EVIDENCE: 4.

"In-bone" utricle cultures--a simplified, atraumatic technique for in situ cultures of the adult mouse (Mus musculus) utricle.

HYPOTHESIS: The "in-bone" method of culturing utricles described here is a reliable and atraumatic technique for culturing mature mouse hair cells and studying hair cell death and protection. BACKGROUND: The current in vitro technique for studying hair cells of the mature mouse utricle involves removal from the temporal bone and free floating culture in media. This technique can be problematic because of variability in the preservation of the sensory epithelium and a steep learning curve that results in injury of the sensory epithelium in less experienced hands. We present a new atraumatic technique of culturing the utricle in situ within the temporal bone. METHODS: Leaving the temporal bone largely intact, a window is opened in the bony vestibule overlying the mouse utricle. The entire temporal bone is then placed into culture media. Utricles were cultured in situ for several days with minimal damage to the epithelium. The utricles are then fixed in situ, removed from the temporal bone, and processed. A standardized aminoglycoside-induced hair cell damage protocol was developed. RESULTS: Mature mouse utricles maintained hair cell numbers for 3 days in culture. Exposure to neomycin resulted in significant dose-dependent hair cell toxicity (p < 0.0001, 1-way analysis of variance). Exposure to the protective drug tacrine resulted in significant protection against neomycin (p < 0.05, 3-way analysis of variance). CONCLUSION: The "in-bone" technique is a reliable and atraumatic method for culturing mature mouse utricles and studying hair cell death and protection. It is easily mastered and can make in vitro study of hair cells accessible to more research groups.