Hearing disorder following COVID-19 vaccination: A pharmacovigilance analysis using the Vaccine Adverse Event Reporting System.

WHAT IS KNOWN AND OBJECTIVE: Evidence on whether the coronavirus disease 2019 (COVID-19) vaccination could cause hearing-related adverse events is still conflicting. This study aims to access the association between COVID-19 vaccine and hearing disorder. METHODS: The Vaccine Adverse Event Reporting System (VAERS) was queried between January 2020 to November 2021. The disproportionality pattern for hearing impairment of COVID-19 vaccine was accessed by calculating the reporting odds ratio (ROR) and proportional reporting ratio (PRR). A further subgroup analysis based on the type of COVID-19 vaccine and the doses administered was performed. In addition, the disproportionalities for hearing dysfunction between COVID-19 and influenza vaccines were compared. RESULTS AND DISCUSSION: A total of 14,956 reports of hearing-related adverse events were identified with COVID-19 vaccination and 151 with influenza vaccine during the analytic period in VAERS. The incidence of hearing disorder following COVID-19 vaccination was 6.66 per 100,000. The results of disproportionality analysis revealed that the adverse events of hearing impairment, after administration of COVID-19 vaccine, was significantly highly reported (ROR 2.38, 95% confidence interval [CI] 2.20-2.56; PRR: 2.35, χ2 537.58), for both mRNA (ROR 2.37, 95% CI 2.20-2.55; PRR 2.34, χ2 529.75) and virus vector vaccines (ROR 2.50, 95% CI 2.28-2.73; PRR 2.56, χ2 418.57). While the disproportional level for hearing dysfunction was quite lower in influenza vaccine (ROR 0.36, 95% CI 0.30-0.42; PRR 0.36, χ2 172.24). WHAT IS NEW AND CONCLUSION: This study identified increased risk for hearing disorder following administration of both mRNA and virus vector COVID-19 vaccines compared to influenza vaccination in real-world settings.

Salicylate toxicity from chronic bismuth subsalicylate use.

A 79-year-old man presented to the emergency department with a 1-week history of worsening confusion, falls and hearing impairment. An initial workup for infectious, metabolic and structural causes was unrevealing. However, further history discovered that he had been ingesting one to two bottles of Pepto-Bismol (bismuth subsalicylate) daily for gastro-oesophageal reflux symptoms. On his second day of admission, the plasma salicylate concentration was 2.08 mmol/L (reference range 1.10-2.20 mmol/L), despite no sources of salicylate in hospital. He was diagnosed with chronic salicylate toxicity and Pepto-Bismol use was discontinued. The patient was treated supportively with isotonic intravenous fluids only and plasma salicylate concentration fell to less than 0.36 mmol/L. Concurrently, all his symptoms resolved. This case highlights the potential adverse effects of over-the-counter medications. The diagnosis of chronic salicylate toxicity is challenging, specifically in the elderly and in undifferentiated presentations, as it can be missed if not suspected.

Don't forget ototoxicity during the SARS-CoV-2 (Covid-19) pandemic!

Aim of this communication is to remind clinical professionals to be aware of ototoxic side effects of several specific drugs proposed for the treatment of the new virus SARS-CoV-2 (Covid-19). In particular, chloroquine and hydroxychloroquine, azithromycin, as well as antiviral drugs such as remdesivir, favipiravir and lopinavir can all present potential ototoxic side effects. The data in the literature do not offer specific information on their potential synergetic effects nor on their interactions.

Attenuation of auditory mismatch negativity in serotonin transporter knockout mice with anxiety-related behaviors.

As the first-line antidepressant drugs, selective serotonin reuptake inhibitors (SSRIs) have efficacy in controlling the symptoms of depression. However, adverse events such as anxiety and hearing disorders were usually observed in patients and even healthy volunteers during the initial phase of SSRI administration. Hearing disorders, including auditory hallucination and tinnitus, are not only highly comorbid with mental disorders but also acknowledged factors that induce psychiatric disorders. The pharmacological and neural mechanisms underlying SSRI-induced anxiety and hearing disorders are not clear. In particularly, the methods evaluating hearing disorders are not well established in animal models, limiting the pre-clinical research on its mechanism. In the present study, we examined the mismatch negativity (MMN), a cognitive component of auditory event-related potential (ERP), to evaluate the hearing process of auditory cortex in mice. Under the acute administration of citalopram, a widely used SSRI, the anxiety-related behaviors and reduced MMN were observed in mice. Serotonin transporter (SERT) is a potential target of SSRIs. The anxiety-related behaviors and reduced MMN were also observed in SERT knockout mice, implying the role of SERT in anxiety and hearing disorders induced by SSRIs. Meanwhile, the auditory brainstem response and initial components of auditory ERP were kept intact in SERT knockout mice, suggesting that hearing neural pathway is less affected by serotonergic system. Our study suggests that the SERT deficient mice might represent a useful animal model in the investigation of the anxiety and hearing disorders during the SSRI treatment.

Phosphodiesterase-5 (PDE-5) Inhibitors and Ototoxicity: A Systematic Review.

OBJECTIVE: This study explores the current literature regarding associations between phosphodiesterase-5 (PDE-5) inhibitors and ototoxicity and provides a detailed summary and discussion of the findings. DATA SOURCES: A comprehensive electronic search of PubMed/MEDLINE, Scopus, and Cochrane Library for studies published from database inception through March 21, 2018. STUDY SELECTION: Basic science articles, epidemiological studies, randomized controlled trials, cohort studies, case reports, reviews, meta-analyses, press releases, and newsletters were included. The PRISMA search strategy was used to select papers. Search terms are included in the appendix (http://links.lww.com/MAO/A733). RESULTS: Twenty-two articles met the inclusion criteria. Among case reports, there were a total of nine patients, all male, with an average age of 57.4 years (37-79 years, SD = 13.87 years). Of the cases of hearing loss, 25% (2/8 cases) were bilateral and 75% (6/8) were unilateral; 22% (2/9) were associated with tinnitus; and 33% (3/9) had accompanying vestibular symptoms (including vertigo and dizziness). Among multipatient studies, all prospective studies failed to find a significant association between ototoxicity and PDE-5 inhibitor use. Results of the retrospective studies were also heterogeneous. Many key molecules in the PDE-5 inhibition pathway have been demonstrated to exist in the cochlea. However, mirroring the clinical studies, the basic science mechanisms have suggested both ototoxic and otoprotective effects. CONCLUSIONS: Currently, the literature is inconclusive regarding the interaction between PDE-5 inhibitor use and ototoxicity. Future study such as a double-blinded placebo controlled randomized trial with audiometric assessment would provide more sound evidence. Similarly, a unified molecular model is necessary.

Hearing Status in Survivors of Childhood Acute Myeloid Leukemia Treated With Chemotherapy Only: A NOPHO-AML Study.

BACKGROUND: As more children survive acute myeloid leukemia (AML) it is increasingly important to assess possible late effects of the intensive treatment. Hearing loss has only sporadically been reported in survivors of childhood AML. We assessed hearing status in survivors of childhood AML treated with chemotherapy alone according to 3 consecutive NOPHO-AML trials. PROCEDURE: A population-based cohort of children treated according to the NOPHO-AML-84, NOPHO-AML-88, and NOPHO-AML-93 trials included 137 eligible survivors among whom 101 (74%) completed a questionnaire and 99 (72%) had otologic and audiologic examination performed including otoscopy (72%), pure tone audiometry (70%), and tympanometry (60%). Eighty-four of 93 (90%) eligible sibling controls completed a similar questionnaire. RESULTS: At a median of 11 years (range, 4 to 25) after diagnosis, hearing disorders were rare in survivors of childhood AML and in sibling controls, with no significant differences. None had severe or profound hearing loss diagnosed at audiometry. Audiometry detected a subclinical hearing loss ranging from slight to moderate in 19% of the survivors, 5% had low-frequency hearing loss, and 17% had high-frequency hearing loss. CONCLUSIONS: The frequency of hearing disorders was low, and hearing thresholds in survivors of childhood AML were similar to background populations of comparable age.

Negative hearing effects of a single course of IV aminoglycoside therapy in cystic fibrosis patients.

OBJECTIVE: Identify hearing effects of a single course of intravenous (IV) aminoglycoside antibiotics (AGs) therapy in adult cystic fibrosis (CF) patients. Determine whether the change is large enough to enable a proof-of-concept study of a new drug preventing AG-associated hearing loss. DESIGN: Retrospective case review of CF patients with sequential audiograms ± an intervening course of IV AG therapy. STUDY SAMPLE: 84 patients with no intervening IV AG treatment, 38 patients undergoing a single course of IV AGs. RESULTS: Using ASHA ototoxicity metrics, 45% of adult CF patients in the Single-IV group met the criteria for ototoxicity compared to 23% of the No-IV patients. Other hearing metrics including the average maximal threshold shift (TS) and average high frequency TS showed highly significant differences between groups. Testing only participants with mild or greater pre-therapy high frequency hearing loss further increased the differences between the two groups by every metric tested. CONCLUSION: Adult CF patients exposed to a single course of IV AGs have significantly greater TS than patients without IV AG exposure. Patients with mild to moderate hearing loss prior to AG-IVs are at increased risk of developing ototoxicity from subsequent parenteral AG therapy.

A Review of the FAERS Data on 5-Alpha Reductase Inhibitors: Implications for Postfinasteride Syndrome.

OBJECTIVE: To quantify reports made to the Food and Drug Administration Adverse Event Reporting System (FAERS), create a demographic of patient reports, and examine the cluster of symptoms to correlate consistency of postfinasteride syndrome (PFS) complaints. PFS is a provisional diagnosis encompassing a cluster of sexual, physical, and psychological and/or neurologic symptoms associated with 5-alpha reductase inhibitor use that emerge or continue after discontinuation of medication. MATERIALS AND METHODS: FAERS dataset of 5-alpha reductase inhibitors from April 2011 to October 2014 was obtained. Each FAERS report had 16 categories for completion, but not every report was fully completed. Statistical analysis compared variables of interest between the 2 doses of finasteride (1 mg vs 5 mg). RESULTS: From FAERS, 2048 monotherapy cases were identified: 1581 of finasteride 1 mg, 240 of finasteride 5 mg, and 226 of unreported doses. Possibly related to labeling changes, from 2011 to 2014, there was a significant increase in adverse events (AEs) reported involving 1 mg dosing. Finasteride use was reported with many sexual AEs including diminished libido, erectile dysfunction, and ejaculatory complaints. Other common AEs included dermatologic, metabolic, and psychological and/or neurologic complaints. There were more AE reports with the 1 mg dose than the 5 mg dose. One case of dutasteride reported back pain, not generally attributed to PFS. CONCLUSION: FAERS data suggests that finasteride exposure is reported with a diverse collection of symptoms, particularly in younger men on 1 mg dosage compared to older men on 5 mg. Many of these complaints fall well out of the realm of previously established AEs from long-term controlled studies.

Cycloserine Induced Suicidal Tendencies and Kanamycin Induced Ototoxicity in Indian MDR-TB Patient: A Case Report.

INTRODUCTION: Cycloserine and Kanamycin are approved for treatment of multidrug-resistant tuberculosis with good tolerability in Tuberculosis patients and have various labeled adverse reactions but the neuropsychiatric adverse drug reactions with cycloserine are rarely explained. CASE REPORT: We present a case report on Cycloserine induced Suicidal tendencies and Kanamycin induced decrease in hearing sensation in Indian MDR-TB patient. A 55-year-old male patient who was diagnosed with MDR-TB was prescribed with category IV anti-tubercular therapy. Within one month of initiation of therapy, he developed repeated suicidal thoughts, joint pain, restlessness, depression, constipation, insomnia, tinnitus and a decrease in hearing sensation. RESULTS AND DISCUSSION: Cycloserine and kanamycin were closely associated with suicidal tendency and tinnitus followed by a decrease in hearing sensations respectively. On causality assessment using WHO-UMC Causality assessment scale, Adverse Drug Reaction with Cycloserine was found to be certain and for kanamycin, ADR was found to be possible. CONCLUSION: Early management of such fatal ADR can improve the compliance, thus preventing the relapse of infection as well as improving therapeutic outcome in Tuberculosis patients.

Sequential analysis as a tool for detection of amikacin ototoxicity in the treatment of multidrug-resistant tuberculosis.

OBJECTIVE: To investigate early detection of amikacin-induced ototoxicity in a population treated for multidrug-resistant tuberculosis (MDR-TB), by means of three different tests: pure-tone audiometry (PTA); high-frequency audiometry (HFA); and distortion-product otoacoustic emission (DPOAE) testing. METHODS: This was a longitudinal prospective cohort study involving patients aged 18-69 years with a diagnosis of MDR-TB who had to receive amikacin for six months as part of their antituberculosis drug regimen for the first time. Hearing was assessed before treatment initiation and at two and six months after treatment initiation. Sequential statistics were used to analyze the results. RESULTS: We included 61 patients, but the final population consisted of 10 patients (7 men and 3 women) because of sequential analysis. Comparison of the test results obtained at two and six months after treatment initiation with those obtained at baseline revealed that HFA at two months and PTA at six months detected hearing threshold shifts consistent with ototoxicity. However, DPOAE testing did not detect such shifts. CONCLUSIONS: The statistical method used in this study makes it possible to conclude that, over the six-month period, amikacin-associated hearing threshold shifts were detected by HFA and PTA, and that DPOAE testing was not efficient in detecting such shifts.

[The hearing function in the premature children following their treatment with the use of ototoxic antibiotics]. / Slukhovaia funktsiia nedonoshennykh detei posle lecheniia ototoksicheskimi antibiotikami.

The objective of the present study was the evaluation of the state of the auditory function in the premature children during the first year of life who underwent the neonatal treatment with various ototoxic antibiotics. A total of 232 newborn infants were available for the examination by the methods designed for recording distortion product optoacoustic emission (DPOAE) and short-latency auditory evoked potentials (SAEPs). The 'Statgraphics Centurion XV' program was used for the statistical treatment of the data obtained in the study. The results of recording DPOAE and SAEPs in 232 prematurely born children of different gestational age were used to evaluate their auditory function under conditions of treatment with various ototoxic antibiotics during the early neonatal period. It was shown that such treatment is likely to have an impact on the hearing function of premature children throughout the entire first year of life. Such influence can manifest itself as the enhanced threshold of the appearance of SAEPs peak V and the selective distortion of evoked responses recorded with the help of the DPOAE technique at a frequency of 4.6 kHz. It is concluded that all prematurely born children should be under observation of an otorhinolaryngologist-surdologist throughout the entire first year of life and, if appropriate, undergo the rehabilitative treatment at the earliest possible time. Moreover, the children with this condition must remain under the thorough follow-up care during at least 3 years including the yearly audiological evaluation and the comparative analysis of the results of previous observations for the timely identification of possible disturbances in the hearing function.

Sequential analysis as a tool for detection of amikacin ototoxicity in the treatment of multidrug-resistant tuberculosis / Análise sequencial como ferramenta na detecção da ototoxicidade da amicacina no tratamento da tuberculose multirresistente

ABSTRACT Objective: To investigate early detection of amikacin-induced ototoxicity in a population treated for multidrug-resistant tuberculosis (MDR-TB), by means of three different tests: pure-tone audiometry (PTA); high-frequency audiometry (HFA); and distortion-product otoacoustic emission (DPOAE) testing. Methods: This was a longitudinal prospective cohort study involving patients aged 18-69 years with a diagnosis of MDR-TB who had to receive amikacin for six months as part of their antituberculosis drug regimen for the first time. Hearing was assessed before treatment initiation and at two and six months after treatment initiation. Sequential statistics were used to analyze the results. Results: We included 61 patients, but the final population consisted of 10 patients (7 men and 3 women) because of sequential analysis. Comparison of the test results obtained at two and six months after treatment initiation with those obtained at baseline revealed that HFA at two months and PTA at six months detected hearing threshold shifts consistent with ototoxicity. However, DPOAE testing did not detect such shifts. Conclusions: The statistical method used in this study makes it possible to conclude that, over the six-month period, amikacin-associated hearing threshold shifts were detected by HFA and PTA, and that DPOAE testing was not efficient in detecting such shifts.

RESUMO Objetivo: Verificar a detecção precoce de ototoxicidade causada pelo uso de amicacina numa população tratada para tuberculose multirresistente (TBMR) por meio da realização de três testes distintos: audiometria tonal liminar (ATL), audiometria de altas frequências (AAF) e pesquisa de emissões otoacústicas por produto de distorção (EOAPD). Métodos: Estudo longitudinal de coorte prospectiva incluindo pacientes de ambos os sexos, com idade entre 18 e 69 anos, com diagnóstico de TBMR pulmonar e que necessitaram utilizar amicacina por seis meses em seu esquema medicamentoso antituberculose pela primeira vez. A avaliação auditiva foi realizada antes do início do tratamento e depois de dois e seis meses do início do tratamento. A análise dos resultados foi realizada por meio de análise estatística sequencial. Resultados: Foram incluídos 61 pacientes, mas a população final foi constituída de 10 pacientes (7 homens e 3 mulheres), em razão da análise sequencial. Ao se comparar os valores das respostas dos testes com aqueles encontrados na avaliação basal, foram verificadas mudanças nos limiares auditivos compatíveis com ototoxicidade após dois meses de tratamento através da AAF e após seis meses de tratamento através da ATL. Entretanto, essas mudanças não foram verificadas através da pesquisa de EOAPD. Conclusões: Ao se considerar o método estatístico utilizado nessa população, é possível concluir que mudanças nos limiares auditivos foram associadas ao uso da amicacina no período de seis meses por meio de AAF e ATL e que a pesquisa de EOAPD não se mostrou eficiente na identificação dessas mudanças.

Concurrent chemoradiotherapy with nedaplatin versus cisplatin in stage II-IVB nasopharyngeal carcinoma: an open-label, non-inferiority, randomised phase 3 trial.

BACKGROUND: Cisplatin-based concurrent chemoradiotherapy is currently considered to be the standard treatment regimen for patients with advanced nasopharyngeal carcinoma, but has well known side-effects such as gastrointestinal reactions, nephrotoxicity, and ototoxicity. Nedaplatin was developed to decrease the toxic effects induced by cisplatin, and in this trial we assessed whether a nedaplatin-based concurrent chemoradiotherapy regimen was non-inferior to a cisplatin-based regimen in patients with locoregional, stage II-IVB nasopharyngeal carcinoma. METHODS: We did an open-label, non-inferiority, phase 3, randomised, controlled trial at two centres in China. Patients aged 18-65 years with non-keratinising stage II-IVB (T1-4N1-3 or T3-4N0) nasopharyngeal carcinoma, a Karnofsky score of at least 70, and adequate haematological, renal, and hepatic function were randomly assigned (1:1) to receive intravenously either nedaplatin 100 mg/m2 or cisplatin 100 mg/m2 on days 1, 22, and 43 for three cycles concurrently with intensity-modulated radiotherapy. Randomisation was done manually using a computer-generated random number code and patients were stratified by treatment centre and clinical stage. Patients and clinicians were not masked to treatment allocation. The primary endpoint was progression-free survival at 2 years; non-inferiority was shown if the upper limit of the 95% CI for the difference in 2-year progression-free survival between the two groups did not exceed 10%. Analyses were by both intention to treat and per protocol, including all patients who received at least one complete cycle of chemotherapy. This trial is registered with ClinicalTrials.gov, number NCT01540136, and is currently in follow-up. FINDINGS: Between Jan 16, 2012, and July 16, 2014, we randomly assigned 402 patients to nedaplatin-based (n=201) or cisplatin-based (n=201) concurrent chemoradiotherapy. In the intention-to-treat population, 2-year progression-free survival was 89·9% (95% CI 85·8-94·0) in the cisplatin group and 88·0% (83·5-94·5) in the nedaplatin group, with a difference of 1·9% (95% CI -4·2 to 8·0; pnon-inferiority=0·0048). In the per-protocol analysis (cisplatin group, n=197; nedaplatin group, n=196), 2-year progression-free survival was 89·7% (95% CI 85·4-94·0) in the cisplatin group and 88·7% (84·2-94·5) in the nedaplatin group, with a difference of 1·0% (95% CI -5·2 to 7·0; pnon-inferiority=0·0020). A significantly higher frequency of grade 3 or 4 vomiting (35 [18%] of 198 in the cisplatin group vs 12 [6%] of 200 in the nedaplatin group, p<0·0001), nausea (18 [9%] vs four [2%], p=0·0021), and anorexia (53 [27%] vs 26 [13%], p=0·00070) was observed in the cisplatin group compared with the nedaplatin group. 11 (6%) patients in the nedaplatin group had grade 3 or 4 thrombocytopenia compared with four (2%) in the cisplatin group (p=0·065). Patients in the cisplatin group had a higher frequency of any grade or grade 3 or 4 late auditory or hearing toxicities than did patients in the nedaplatin group (grade 3 or 4: three [2%] in the nedaplatin group vs 11 [6%] in the cisplatin group, p=0·030). No patients died from treatment-related causes. INTERPRETATION: Our findings show that nedaplatin-based concurrent chemoradiotherapy represents an alternative doublet treatment strategy to cisplatin-based concurrent chemoradiotherapy for patients with locoregional, advanced nasopharyngeal carcinoma. Further investigations are needed to explore the potential use of this treatment as induction or adjuvant chemotherapy or in combination with other agents. FUNDING: National Key R&D Program of China, National Natural Science Foundation of China, Sun Yat-sen University Clinical Research 5010 Program, Sci-Tech Project Foundation of Guangzhou City, National Key Basic Research Program of China, Special Support Plan of Guangdong Province, Sci-Tech Project Foundation of Guangdong Province, Health & Medical Collaborative Innovation Project of Guangzhou City, National Science & Technology Pillar Program during the Twelfth Five-year Plan Period, PhD Start-up Fund of Natural Science Foundation of Guangdong Province, Cultivation Foundation for the Junior Teachers in Sun Yat-sen University, and Fundamental Research Funds for the Central Universities.

Drug-Induced Ototoxicity: Diagnosis and Monitoring.

Ototoxicity diagnosis and management has historically been approached using a variety of methods. However, in recent years a consensus on useful and practical approaches has been developed through clinical guidelines of the American Speech Language Hearing Association, the American Academy of Audiology, and multiple clinical trials published in peer-reviewed literature. Some of the guidelines and approaches are used to detect and monitor ototoxicity, while others are used to grade adverse events. Some of the audiologic measures are primary, while others are adjunct measures and may be tailored to the specific needs of the patient or clinical trial. For some types of monitoring, such as drug-induced tinnitus or dizziness, validated paper survey instruments can be both sensitive and easy for fragile patients. This review addresses the characteristics of some of the most common clinical ototoxins and the most common methods for detecting and monitoring ototoxicity in clinical practice and clinical trials.

The glucocorticoid antagonist mifepristone attenuates sound-induced long-term deficits in auditory nerve response and central auditory processing in female rats.

Systemic corticosteroids have been the mainstay of treatment for various hearing disorders for more than 30 yr. Accordingly, numerous studies have described glucocorticoids (GCs) and stressors to be protective in the auditory organ against damage associated with a variety of health conditions, including noise exposure. Conversely, stressors are also predictive risk factors for hearing disorders. How both of these contrasting stress actions are linked has remained elusive. Here, we demonstrate that higher corticosterone levels during acoustic trauma in female rats is highly correlated with a decline of auditory fiber responses in high-frequency cochlear regions, and that hearing thresholds and the outer hair cell functions (distortion products of otoacoustic emissions) are left unaffected. Moreover, when GC receptor (GR) or mineralocorticoid receptor (MR) activation was antagonized by mifepristone or spironolactone, respectively, GR, but not MR, inhibition significantly and permanently attenuated trauma-induced effects on auditory fiber responses, including inner hair cell ribbon loss and related reductions of early and late auditory brainstem responses. These findings strongly imply that higher corticosterone stress levels profoundly impair auditory nerve processing, which may influence central auditory acuity. These changes are likely GR mediated as they are prevented by mifepristone.-Singer, W., Kasini, K., Manthey, M., Eckert, P., Armbruster, P., Vogt, M. A., Jaumann, M., Dotta, M., Yamahara, K., Harasztosi, C., Zimmermann, U., Knipper, M., Rüttiger, L. The glucocorticoid antagonist mifepristone attenuates sound-induced long-term deficits in auditory nerve response and central auditory processing in female rats.

Transcriptomic analysis of chicken cochleae after gentamicin damage and the involvement of four signaling pathways (Notch, FGF, Wnt and BMP) in hair cell regeneration.

Unlike mammalian hair cells, which are essentially unable to regenerate after damage, avian hair cells have a robust capacity for regeneration. The prerequisite for understanding the above difference is knowing the genetic programming of avian hair cell regeneration. Although the major processes have been known, the precise molecular signaling that induces regeneration remains unclear. To address this issue, we performed a high-throughput transcriptomic analysis of gene expression during hair cell regeneration in the chick cochlea after antibiotic injury in vivo. A total of 16,588 genes were found to be expressed in the cochlea, of which about 1000 genes were differentially expressed among the four groups studied, i.e., 2 days (d) or 3 d post-treatment with gentamicin or physiological saline. The differentially expressed genes were distributed across approximately one hundred signaling pathways, including the Notch, MAPK (FGF), Wnt and TGF-ß (BMP) pathways that have been shown to play important roles in embryonic development. Some differentially expressed genes (2-3 in each pathway) were further verified by qRT-PCR. After blocking Notch, FGF or BMP signaling, the number of regenerating hair cells and mitotic supporting cells increased. However, the opposite effect was observed after suppressing the Wnt pathway or enhancing BMP signaling. To our knowledge, the present study provided a relatively complete dataset of candidate genes and signaling pathways most likely involved in hair cell regeneration and should be a useful start in deciphering the genetic circuitry for inducing hair cell regeneration in the chick cochlea.

Therapeutic and protective effects of autologous serum in amikacin-induced ototoxicity.

OBJECTIVE: Possible therapeutic and protective benefits of intratympanic autologous serum application in amikacin-induced ototoxicity were investigated. METHODS: Twenty-four guinea pigs were separated equally into two groups: therapeutic (group A) and protective (group B). Transient evoked otoacoustic emissions were recorded before and after autologous serum application. Apoptotic cells were identified in the organ of Corti, spiral limbus and spiral ganglion by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling ('TUNEL') method. RESULTS: Transient evoked otoacoustic emission responses at 1, 1.4 and 2.8 kHz improved without significance after autologous serum application in group A (p > 0.05). A significantly protective effect of autologous serum was determined at 4 kHz in group B (p < 0.05). There were significantly fewer apoptotic cells at the spiral limbus in the therapeutic and protective groups compared to the control group (p < 0.05). CONCLUSION: Autologous serum may offer protection against ototoxicity-induced hearing loss, but it cannot restore hearing. Immunohistochemically, autologous serum significantly decreases activation of the intrinsic pathway of pro-apoptotic signalling in mesenchymal cells compared to neurons and neurosensory cells.

Seguridad vial, asma y rinitis: reflexiones / Road safety, asthma and rhinitis: reflections

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Salicylate-induced frequency-map reorganization in four subfields of the mouse auditory cortex.

Salicylate is the active ingredient in aspirin, and in high-doses it is used as an experimental tool to induce transient hearing loss, tinnitus, and hyperacusis. These salicylate-induced perceptual disturbances are associated with tonotopic-map reorganization and neural activity modulation, and such neural correlates have been examined in the central auditory pathway, including the auditory cortex (AC). Although previous studies have reported that salicylate induces increases in noise-burst-evoked neural responses and reorganization of tonotopic maps in the primary AC, little is known about the effects of salicylate on other frequency-organized AC subfields such as the anterior auditory, secondary auditory, and dorsomedial fields. Therefore, to examine salicylate-induced spatiotemporal effects on AC subfields, we measured sound-evoked neural activity in mice before and after the administration of sodium salicylate (SS, 200 mg/kg), using flavoprotein auto-fluorescence imaging. SS-treatment gradually reduced responses driven by tone-bursts with lower (≤8 kHz) and higher (≥25 kHz) frequencies over 3 h, whereas evoked responses to tone-bursts within middle-range frequencies (e.g., 12 and 16 kHz) were sustained and unchanged in the four subfields. Additionally, in each of the four subfields, SS-treatment induced similar reorganization of tonotopic maps, and the response areas selectively driven by the middle-range frequencies were profoundly expanded. Our results indicate that the SS-induced tonotopic map reorganizations in each of the four AC subfields were similar, and only the extent of the activated areas responsive to tone-bursts with specific frequencies was subfield-dependent. Thus, we expect that examining cortical reorganization induced by SS may open the possibility of new treatments aimed at altering cortical reorganization into the normative functional organization.

When students become patients: TB disease among medical undergraduates in Cape Town, South Africa.

BACKGROUND: Medical students acquire latent tuberculosis (TB) infection at a rate of 23 cases/100 person-years. The frequency and impact of occupational TB disease in this population are unknown. METHODS: A self-administered questionnaire was distributed via email and social media to current medical students and recently graduated doctors (2010 - 2015) at two medical schools in Cape Town. Individuals who had developed TB disease as undergraduate students were eligible to participate. Quantitative and qualitative data collected from the questionnaire and semi-structured interviews were analysed with descriptive statistics and a framework approach to identify emerging themes. RESULTS: Twelve individuals (10 female) reported a diagnosis of TB: pulmonary TB (n=6), pleural TB (n=3), TB lymphadenitis (n=2) and TB spine (n=1); 2/12 (17%) had drug-resistant disease (DR-TB). Mean diagnostic delay post consultation was 8.1 weeks, with only 42% of initial diagnoses being correct. Most consulted private healthcare providers (general practitioners (n=7); pulmonologists (n=4)), and nine underwent invasive procedures (bronchoscopy, pleural fluid aspiration and tissue biopsy). Substantial healthcare costs were incurred (mean ZAR25 000 for drug-sensitive TB, up to  ZAR104 000 for DR-TB). Students struggled to obtain treatment, incurred high transport costs and missed academic time. Students with DR-TB interrupted their studies and experienced severe side-effects (hepatotoxicity, depression and permanent ototoxicity). Most participants cited poor TB infection-control practices at their training hospitals as a major risk factor for occupational TB. CONCLUSIONS: Undergraduate medical students in Cape Town are at high risk of occupationally acquired TB, with an unmet need for comprehensive occupational health services and support.