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OBJECTIVES: This study aimed to evaluate potential therapeutic effect of Metagonimus yokogawai on the OVA-induced allergic rhinitis model. METHODS: OVA-sensitized mice were used to assess potential therapeutic effect of the extract protein of M. yokogawai (My-TP). My-TP was administrated via the intralymphatic route to cervical lymph nodes. The frequencies of sneezing or nasal rubbing were recorded. Histopathologic evaluation was performed for eosinophil infiltrations in the tissues of the nasal mucosa and skin. The mRNA relative expressions of the cytokine profiles including Th1, Th2, Th17, and Treg subsets in the nasal mucosa, cervical lymph nodes, and spleen were analyzed by quantitative real-time reverse-transcriptase polymerase chain reaction. The potential underlying mechanism was investigated by examining cytokine profiles including IL-4 and Treg subsets from lymphocytes of the spleen by flow cytometry. RESULTS: Intralymphatic injection of My-TP reduced allergic symptoms and eosinophil infiltration in the nasal mucosa. My-TP-treated group showed markedly decreased levels of OVA-specific IgE and WBC counts in nasal lavage. My-TP-treated group showed the decreased expression levels of IL-4, while those of IL-10 were increased in both the nasal mucosa. The levels of IFN-γ and IL-17 were also decreased in the nasal mucosa and cervical lymph nodes. The immunological mechanism may involve the downregulation of Th2 response and upregulation of Tregs in the nasal mucosa and cervical lymph nodes. CONCLUSIONS: Our results provide the first evidence of potential therapeutic effect of M. yokogawai in OVA-sensitized allergic rhinitis mice, suggesting that a Treg/Th2 reorganization may play a role in clinical course of allergic rhinitis.
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Antialérgicos/administración & dosificación , Productos Biológicos/administración & dosificación , Heterophyidae/química , Rinitis Alérgica/tratamiento farmacológico , Rinitis Alérgica/inmunología , Animales , Citocinas/metabolismo , Modelos Animales de Enfermedad , Eosinófilos/inmunología , Eosinófilos/patología , Ratones , Rinitis Alérgica/diagnóstico , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Terapia con Helmintos , Resultado del TratamientoAsunto(s)
Obstrucción de las Vías Aéreas/complicaciones , Obstrucción de las Vías Aéreas/terapia , Obesidad/complicaciones , Respiración Artificial/métodos , Índice de Severidad de la Enfermedad , Síndromes de la Apnea del Sueño/complicaciones , Síndromes de la Apnea del Sueño/terapia , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores de RiesgoRESUMEN
Hearing loss in older people can cause communication impairments, decreased quality of life, social isolation, depression, and dementia. Cochlear implant surgery is an effective treatment for older patients with hearing loss who cannot achieve satisfactory audiologic outcomes with hearing aids. However, older people have an increased risk of heart disease and often take medications that affect heart rhythm. Herein, we report a case of an 80-year-old woman who underwent cardioversion at 50J after cochlear implant surgery. Electrical impedance before and after cardioversion showed only minor changes without abnormality, and the cochlear implant functioned well. We believe that the electronic circuits of the cochlear implant may have been relatively tolerant to the electrical shock from the external defibrillator. Typically, cardioversion should be avoided in cochlear implant recipients because it may damage the implant. If cardioversion cannot be avoided, we strongly recommend starting cardioversion at the lowest energy level (50 J) and removing the sound processor of the implant during the procedure.
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Aleteo Atrial , Implantes Cocleares , Sordera , Pérdida Auditiva , Femenino , Humanos , Anciano , Anciano de 80 o más Años , Cardioversión Eléctrica/efectos adversos , Cardioversión Eléctrica/métodos , Aleteo Atrial/etiología , Calidad de Vida , Arritmias Cardíacas/etiología , Pérdida Auditiva/etiologíaRESUMEN
PURPOSE: Cluster analyses on inflammatory markers of chronic rhinosinusitis (CRS) in Asians from multicenter data are lacking. This multicenter study aimed to identify the endotypes of CRS in Koreans and to evaluate the relationship between the endotypes and clinical parameters. METHODS: Nasal tissues were obtained from patients with CRS and controls who underwent surgery. The endotypes of CRS were investigated by measuring interleukin (IL)-5, interferon (IFN)-γ, IL-17A, IL-22, IL-1ß, IL-6, IL-8, matrix metalloproteinase-9, eotaxin-3, eosinophil cationic protein, myeloperoxidase (MPO), human neutrophil elastase (HNE), periostin, transforming growth factor-ß1, total immunoglobulin E (IgE), and staphylococcal enterotoxin (SE)-specific IgE. We performed hierarchical cluster analysis and evaluated the phenotype, comorbidities, and Lund-Mackay computed tomography (LM CT) score in each cluster. RESULTS: Five clusters and 3 endotypes were extracted from 244 CRS patients: cluster 1 had no upregulated mediators compared to the other clusters (mild mixed inflammatory CRS); clusters 2, 3, and 4 had higher concentrations of neutrophil-associated mediators including HNE, IL-8, IL-17A, and MPO (T3 CRS); and cluster 5 had higher levels of eosinophil-associated mediators (T2 CRS). SE-specific IgE was undetectable in T3 CRS and had low detectable levels (6.2%) even in T2 CRS. The CRS with nasal polyps (CRSwNP) phenotype and LM CT scores showed no significant differences between T2 and T3 CRS, while the incidence of comorbid asthma was higher in T2 CRS than T3 CRS. In T3 clusters, higher levels of neutrophilic markers were associated with disease severity and CRSwNP phenotype. CONCLUSIONS: In Koreans, there is a distinct T3 CRS endotype showing a high proportion of CRSwNP and severe disease extent, along with T2 CRS.
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Rationale: The anatomic orientation of the epiglottis is such that it points in the opposite direction to inspiratory flow, thereby potentially making positive airway pressure (PAP) treatment challenging in patients with epiglottic collapse. However, no previous studies have analyzed PAP adherence in these patients. Objectives: This study aimed to analyze adherence to autotitrating PAP (APAP) treatment in patients with epiglottic collapse. Methods: We performed an age- and sex-matched case-control study. On the basis of their overnight level-I polysomnogram, patients were prescribed APAP in a tertiary hospital between July 2018 and March 2019. The site of airway collapse was diagnosed with drug-induced sleep endoscopy. Demographic factors, sleep questionnaire, polysomnography, and APAP usage statistics were analyzed. Results: Eighteen patients with epiglottic collapse (epi-group) and 36 without epiglottic collapse (control group) were analyzed. We found that 22.8% of patients in the epi-group terminated APAP within 2 weeks, whereas only 2.8% of patients in the control group terminated APAP within 2 weeks (P = 0.048). The percentage of days with usage over 4 hours was significantly lower in the epi-group (64.6% vs. 75.6%; P = 0.008). In addition, the adherence failure rate was 66.7% in the epi-group and 33.3% in the control group (P = 0.039). Patients with epiglottic collapse were also found to have lower body mass index, which is an unfavorable predictor of APAP adherence. Conclusions: This study suggests that patients with epiglottic collapse have a higher APAP adherence failure rate than patients without epiglottic collapse. Thus, patients with epiglottic collapse should be followed closely during treatment, and alternative therapies should probably be considered for these patients.
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Epiglotis , Apnea Obstructiva del Sueño , Humanos , Estudios de Casos y Controles , Presión de las Vías Aéreas Positiva Contínua , Polisomnografía , Apnea Obstructiva del Sueño/terapiaRESUMEN
PURPOSE: Head rotation is thought to have an effect on obstructive sleep apnea (OSA) severity. However, keeping the head rotated fully during sleep is difficult to maintain, and the effect of head rotation is not the same in all OSA patients. Thus, this study aimed to identify whether less head rotation has an effect on airway patency and determine the responder characteristics to the head rotation maneuver (HRM). METHODS: We recruited 221 patients who underwent overnight polysomnography and drug-induced sleep endoscopy (DISE) in a tertiary hospital from June 2019 to July 2020. Airway patency and the site of airway collapse were determined in the supine position with the head at 0, 30, and 60 degrees of rotation (HRM0°, HRM30°, and HRM60°, respectively) during DISE. The site of collapse was determined using the VOTE classification system: the velum (palate), oropharyngeal lateral walls, tongue base, and epiglottis. Each structure was labeled as 0, 1, or 2 (patent, partially obstructed, and completely obstructed, respectively). Airway response to the HRM30° and 60° and the clinical characteristics associated with airway opening were analyzed. RESULTS: The study population had a median age of 52 (25-61) years, a body mass index of 26.7(24.6-29.4) kg/m2, and the apnea-hypopnea index (AHI) of 28.2(13.7-71.9) events/h. HRM influenced airway patency positively not only with HRM60° (p<0.001) but also following limited rotation (HRM30°, p<0.001). Patients with tongue base (40.0% with HRM 60°) and epiglottic (52.6% with HRM 60°) collapse responded particularly well to HRM. Multivariate analysis revealed that lower AHI (p<0.001) and an absence of oropharyngeal lateral walls collapse (p = 0.011) were significant predictors of responders to HRM. CONCLUSION: Head rotation improved airway obstruction in OSA patients, even with a small degree of rotation, and should be further explored as a potential form of therapy in appropriately selected patients.
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Obstrucción de las Vías Aéreas/terapia , Orofaringe/patología , Choque , Apnea Obstructiva del Sueño/terapia , Adulto , Endoscopía , Epiglotis/fisiología , Cabeza/fisiología , Humanos , Persona de Mediana Edad , Análisis Multivariante , Orofaringe/fisiopatología , Hueso Paladar/fisiología , Polisomnografía , Rotación , Sueño , Centros de Atención Terciaria , Lengua/fisiologíaRESUMEN
INTRODUCTION: Foreign body (FB) aspiration is one of the causes of respiratory distress in infants is an extremely dangerous and potentially life-threatening event. The diagnosis of FB aspiration is difficult because the signs and symptoms vary according to the degree of airway blockage or location of the FB. PATIENT CONCERNS: An 11-month-old female infant visited a hospital because of a sudden onset cough. She was relatively healthy without fever, rhinorrhea cyanosis, or poor feeding. On physical examination, auscultation revealed inspiratory stridor without wheezing and crackles. DIAGNOSIS: Croup was suspected when considering the history, physical examination, and imaging. However, she did not respond to a 4-day course of treatment for croup. Flexible laryngoscopic examination was performed, and we identified a thin, flat, and sharp FB embedded in the subglottic region. INTERVENTIONS: Emergency surgery was performed to remove the FB. Short-term intravenous corticosteroids and antibiotics were used to prevent laryngeal swelling and aspiration pneumonia. OUTCOMES: One week after the procedure, the laryngeal mucosa had completely healed. CONCLUSION: FB aspiration should be considered in an infant with an impression of croup. In particular, if there is no response to medical or conservative treatment for croup, further evaluation is needed.
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Cuerpos Extraños/diagnóstico , Tos , Crup/diagnóstico , Diagnóstico Diferencial , Femenino , Cuerpos Extraños/diagnóstico por imagen , Cuerpos Extraños/cirugía , Humanos , Lactante , LaringoscopíaRESUMEN
STUDY OBJECTIVES: The purpose of this study was to analyze patients with epiglottic collapse, especially their clinical characteristics related to obstructive sleep apnea and phenotype labeling using drug-induced sleep endoscopy. METHODS: An age-sex matched case-control study was conducted to compare the clinical characteristics of patients with epiglottic collapse (Epi group) and patients without epiglottic collapse (non-Epi group). All patients underwent drug-induced sleep endoscopy January, 2015, to March, 2019, in a tertiary hospital for suspected sleep apnea symptoms. Demographic factors, underlying disease, overnight polysomnography, and their phenotype labeling using drug-induced sleep endoscopy were analyzed. RESULTS: There was no difference in age, sex, the prevalence of hypertension, diabetes, cerebrovascular disease, and coronary artery disease. However, the body mass index was significantly lower in patients in the Epi group (P < .001). Additionally, the apnea-hypopnea index was lower (P = .001), and the lowest oxygen saturation was significantly higher in the Epi group (P = .042). The phenotype labeling on drug-induced sleep endoscopy showed that the prevalence of velum concentric collapse and oropharyngeal lateral wall collapse was lower, and that of tongue-base collapse was higher in the Epi group. Multilevel obstructions were more common in the Epi group. However, the Epi group showed a good response to mandibular advancement or positional therapy. CONCLUSIONS: Although there was no difference in the underlying characteristics and self-reported symptom scores between the groups, the patients with epiglottic collapse showed significantly lower body mass index and obstructive sleep apnea severity. Additionally, patients with epiglottic collapse were expected to respond well to oral devices or positional therapy.
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Obstrucción de las Vías Aéreas , Apnea Obstructiva del Sueño , Estudios de Casos y Controles , Presión de las Vías Aéreas Positiva Contínua , Endoscopía , Humanos , PolisomnografíaRESUMEN
OBJECTIVE: We analyzed the clinical characteristics of patients with isolated epiglottic collapse (IEC) who had an epiglottic anteroposterior (AP) collapse as the only cause of snoring during drug-induced sleep endoscopy (DISE). METHODS: A retrospective analysis of 334 consecutive DISE examinations was performed. Patients who had only epiglottic AP collapse were designated as the IEC group. There were four age- and sex-matched controls for each case, and these patients were designated as the control group. Demographic factors, polysomnography findings, cephalometry, and awake nasopharyngoscopic findings were analyzed. RESULTS: A total of 11 IEC cases and 44 controls were included. The IEC group had a significantly lower apnea-hypopnea index, higher minimum oxygen saturation level, lower body mass index, and shorter mandible plane to hyoid distance than the controls. However, there were no differences in epiglottic shape or curvature between the two groups. In addition, no IEC was noted during awake endoscopy. Nine (81.8%) epiglottic collapses were resolved with the mouth open and jaw thrust maneuver, which simulated the use of an oral appliance. Six (54.4%) were resolved with head turning, mimicking the lateral sleep position. CONCLUSION: The clinical characteristics of IEC patients differed from the control group, and IEC could not be identified during awake endoscopy. Therefore, patients with severe snoring but AHI < 5 or mild sleep apnea on polysomnographic findings and DISE, should be considered likely to have IEC. In addition, use of an oral appliance is recommended as an effective treatment for IEC.
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Epiglotis/fisiopatología , Síndromes de la Apnea del Sueño/etiología , Ronquido/etiología , Adulto , Estudios de Casos y Controles , Endoscopía , Epiglotis/cirugía , Femenino , Humanos , Masculino , Estudios Retrospectivos , Apnea Obstructiva del Sueño/etiologíaRESUMEN
BACKGROUND: In this study we evaluated the effects of inferior turbinate radiofrequency ablation (RFA), performed after septoplasty, on patients with allergic rhinitis (AR) symptoms. METHODS: This was a prospective, randomized, controlled study involving 60 patients with both a deviated nasal septum (DNS) and AR. Those who underwent septoplasty/sham surgery constituted the Septo-Sham group and those who underwent septoplasty/RFA formed the Septo-RFA group. Demographic factors, pre- and postoperative symptom scores for allergic rhinitis (SFARs), and Nasal Obstruction and Septoplasty Effectiveness Scale (NOSE) scores were calculated. We subdivided the total SFAR (tSFAR) scores into scores for nasal obstruction (SFAR-NO) and scores for symptoms other than nasal obstruction (SFAR-SONO); the latter included rhinorrhea, itching, and sneezing. RESULTS: The baseline characteristics were similar between the groups. The 2 types of surgery improved both the NOSE and SFAR scores. In subgroup analysis according to the type of symptoms, both types of surgery showed improvement in SFAR-NO and SFAR-SONO scores. However, the extent of improvement did not differ between the groups, regardless of the type of symptoms. CONCLUSION: For patients with both DNS and AR, both types of surgery afford postoperative symptomatic improvement. Both types of surgery yielded improvement in both nasal obstruction and symptoms other than nasal obstruction. However, performing RFA after septoplasty did not afford further short-term symptomatic improvements. Thus, septoplasty without RFA may be optimal for patients with both DNS and AR.
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Obstrucción Nasal/terapia , Tabique Nasal/cirugía , Ablación por Radiofrecuencia/métodos , Rinitis Alérgica/terapia , Rinoplastia , Cornetes Nasales/cirugía , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Obstrucción Nasal/cirugía , Periodo Posoperatorio , Estudios Prospectivos , Rinitis Alérgica/cirugía , Resultado del Tratamiento , Adulto JovenRESUMEN
INTRODUCTION: Methicillin-resistant staphylococcus aureus is an emerging problem for the treatment of chronic suppurative otitis media, and also for pediatric tympanostomy tube otorrhea. To date, there are no effective topical antibiotic drugs to treat methicillin-resistant staphylococcus aureus otorrhea. OBJECTIVE: In this study, we evaluated the ototoxicity of topical KR-12-a2 solution on the cochlea when it is applied topically in the middle ear of guinea pigs. METHODS: The antimicrobial activity of KR-12-a2 against methicillin-resistant staphylococcus aureus strains was examined by using the inhibition zone test. Topical application of KR-12-a2 solution, gentamicin and phosphate buffered saline were applied in the middle ear of the guinea pigs after inserting ventilation tubes. Ototoxicity was assessed by auditory brainstem evoked response and scanning electron microscope examination. RESULTS: KR-12-a2 produced an inhibition zone against methicillin-resistant staphylococcus aureus from 6.25 µg. Hearing threshold in the KR-12-a2 and PBS groups were similar to that before ventilation tube insertion. However, the gentamicin group showed elevation of the hearing threshold and there were statistically significant differences compared to the phosphate buffered saline or the KR-12-a2 group. In the scanning electron microscope findings, the KR-12-a2 group showed intact outer hair cells. However, the gentamicin group showed total loss of outer hair cells. In our experiment, topically applied KR-12-a2 solution did not cause hearing loss or cochlear damage in guinea pigs. CONCLUSION: In our experiment, topically applied KR-12-a2 solution did not cause hearing loss or cochlear damage in guinea pigs. The KR-12-a2 solution can be used as ototopical drops for treating methicillin-resistant staphylococcus aureus otorrhea; however, further evaluations, such as the definition of optimal concentration and combination, are necessary.
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Antibacterianos/toxicidad , Catelicidinas/toxicidad , Cóclea/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Fragmentos de Péptidos/toxicidad , Administración Tópica , Animales , Antibacterianos/administración & dosificación , Umbral Auditivo , Catelicidinas/administración & dosificación , Cóclea/fisiopatología , Modelos Animales de Enfermedad , Potenciales Evocados Auditivos del Tronco Encefálico , Cobayas , Células Ciliadas Auditivas/efectos de los fármacos , Masculino , Pruebas de Sensibilidad Microbiana , Microscopía Electrónica de Rastreo , Otitis Media Supurativa/microbiología , Fragmentos de Péptidos/administración & dosificación , Reproducibilidad de los Resultados , Infecciones Estafilocócicas/tratamiento farmacológico , Resultado del TratamientoRESUMEN
BACKGROUND & OBJECTIVE: External auditory canal cholesteatoma (EACC) is caused by an invasion of squamous tissue into a localized area of periosteitis in the bony canal wall. The clinical characteristics of pediatric EACC are still unknown because of its rare occurrence. To date, only a single paper has reported that pediatric EACC has a less aggressive growth pattern compared to adult EACC. Further studies are required to understand the clinical behavior of EACC, i.e., its aggressiveness. The purpose of this study was to evaluate the clinical characteristics of pediatric EACC. MATERIALS AND METHODS: The clinical records of all patients diagnosed with EACC in our department from January 1, 2012 to February 29, 2016 were retrospectively reviewed, focusing on the extension of bone erosion, symptoms, and clinical findings. RESULTS: Seven patients had primary pediatric EACC (age range, 5-17 years). All patients showed unilateral EACC. Otalgia and intermittent otorrhea were common symptoms. Bacterial cultures were performed for four patients with otorrhea, which was controlled by diluted vinegar irrigation with a topical antibiotic solution. The most common bone destruction sites were the inferior and posterior walls. All patients required surgical treatment. Four patients (patient nos. 1, 3, 4, and 5) were treated via a postauricular transcanal approach. Three patients (patient nos. 2, 6, and 7) required mastoidectomy. CONCLUSION: Pediatric EACC is not less aggressive than adult EACC. Therefore, early diagnosis and adequate treatment are necessary. Further studies are required to elucidate the clinical features of pediatric spontaneous EACC.
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Enfermedades Óseas/etiología , Colesteatoma/complicaciones , Colesteatoma/cirugía , Dolor de Oído/etiología , Adolescente , Antibacterianos/uso terapéutico , Niño , Preescolar , Colesteatoma/microbiología , Conducto Auditivo Externo , Femenino , Humanos , Masculino , Apófisis Mastoides/cirugía , Estudios RetrospectivosRESUMEN
OBJECTIVE: Recently, minimally invasive transcanal myringotomy (MITM), which is a useful surgical technique for early stage congenital cholesteatoma (CC) in children, was introduced. The purpose of this study is to evaluate the short-term surgical results of MITM in pediatric early stage CC. MATERIALS AND METHODS: We retrospectively reviewed the charts of 24 patients who underwent MITM between January 2013 and October 2015. RESULTS: The patients' ages ranged from 1 to 16 years (mean, 2.6 years). There were 17 male and 7 female patients. The right side (n = 13) was affected twice as often as the left side (n = 11). The most common site was the anterosuperior quadrant (15 cases). The diameter of the CC on axial computed tomography images ranged from 2.8 to 5.7 mm (mean, 3.9 mm). CCs were graded according to Potsic's system: 18 cases were classified as stage I, 3 case as stage II, and 3 cases as stage III. AllCCs except 1 were closed type. In21 patients, the tympanic membrane closed naturally without recurrence. Three patients showed small persistent dry perforation. Natural closure occurred in these patients, who were treated with paper patches. CONCLUSION: MITM is a simple, effective technique for removing an early stage CC from the middle ear, and it can minimize operative time, length of hospitalization, and postoperative morbidity.
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Colesteatoma del Oído Medio/cirugía , Colesteatoma/congénito , Ventilación del Oído Medio/métodos , Adolescente , Niño , Preescolar , Colesteatoma/diagnóstico por imagen , Colesteatoma/cirugía , Colesteatoma del Oído Medio/diagnóstico por imagen , Femenino , Hospitalización , Humanos , Lactante , Tiempo de Internación , Masculino , Procedimientos Quirúrgicos Mínimamente Invasivos , Tempo Operativo , Otoscopía , Recurrencia , Estudios Retrospectivos , Tomografía Computarizada por Rayos X , Resultado del TratamientoRESUMEN
Abstract Introduction Methicillin-resistant staphylococcus aureus is an emerging problem for the treatment of chronic suppurative otitis media, and also for pediatric tympanostomy tube otorrhea. To date, there are no effective topical antibiotic drugs to treat methicillin-resistant staphylococcus aureus otorrhea. Objective In this study, we evaluated the ototoxicity of topical KR-12-a2 solution on the cochlea when it is applied topically in the middle ear of guinea pigs. Methods The antimicrobial activity of KR-12-a2 against methicillin-resistant staphylococcus aureus strains was examined by using the inhibition zone test. Topical application of KR-12-a2 solution, gentamicin and phosphate buffered saline were applied in the middle ear of the guinea pigs after inserting ventilation tubes. Ototoxicity was assessed by auditory brainstem evoked response and scanning electron microscope examination. Results KR-12-a2 produced an inhibition zone against methicillin-resistant staphylococcus aureus from 6.25 µg. Hearing threshold in the KR-12-a2 and PBS groups were similar to that before ventilation tube insertion. However, the gentamicin group showed elevation of the hearing threshold and there were statistically significant differences compared to the phosphate buffered saline or the KR-12-a2 group. In the scanning electron microscope findings, the KR-12-a2 group showed intact outer hair cells. However, the gentamicin group showed total loss of outer hair cells. In our experiment, topically applied KR-12-a2 solution did not cause hearing loss or cochlear damage in guinea pigs. Conclusion In our experiment, topically applied KR-12-a2 solution did not cause hearing loss or cochlear damage in guinea pigs. The KR-12-a2 solution can be used as ototopical drops for treating methicillin-resistant staphylococcus aureus otorrhea; however, further evaluations, such as the definition of optimal concentration and combination, are necessary.
Resumo Introdução O staphylococcus aureus resistente à meticilina é um problema emergente não só para a otite média supurativa crônica, mas também para casos de otorreia crônica em crianças com tubo de ventilação. Até o momento, não há antibióticos tópicos efetivos para a otorreia causada por staphylococcus aureus resistente à meticilina. Objetivo Nesse estudo, avaliamos a ototoxicidade da solução tópica de KR-12-a2 na cóclea quando aplicada topicamente na orelha média de cobaias. Método A atividade antimicrobiana de KR-12-a2 contra cepas de staphylococcus aureus resistente à meticilina foi avaliada utilizando-se o teste de zona de inibição de crescimento. Foram aplicados na orelhas médias de 3 grupos de cobaias, ou solução tópica de KR-12-a2, ou gentamicina ou solução salina tamponada com fosfato após timpanostomia. A ototoxicidade foi avaliada através do exame auditivo de potencial evocado auditivo de tronco encefálico e por microscopia eletrônica de varredura. Resultados O KR-12-a2 produziu uma zona de inibição contra o staphylococcus aureus resistente à meticilina a partir de 6,25 µg. Alterações do limiar de audição no grupo KR-12-a2 e no grupo com solução salina foram semelhantes aos observados antes da inserção do tubo de ventilação. No entanto, o grupo gentamicina apresentou um limiar auditivo mais elevado, estatisticamente significativo em comparação ao grupo solução salina ou ao grupo KR-12-a2. Nos achados da microscopia eletrônica, o grupo KR-12-a2 apresentou células ciliadas externas intactas. No entanto, o grupo gentamicina apresentou perda total das células ciliadas externas. Em nosso experimento, a solução de KR-12-a2 aplicada topicamente não causou perda auditiva ou dano coclear em cobaias. Conclusão Em nosso experimento, a solução de KR-12-a2 aplicada topicamente não causou perda auditiva ou dano coclear em cobaias. A solução de KR-12-a2 pode ser utilizada como gotas otológicas para o tratamento da otorreia causada por staphylococcus aureus resistente à meticilina; no entanto, são necessárias outras avaliações, para a definição da concentração e das associações ideais.