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Fons JM, Milmoe NJ, Dack MRG, Joshi L, Thompson H, Tucker AS. The interconnected relationships between middle ear bulla size, cavitation defects, and chronic otitis media revealed in a syndromic mouse model. Front Genet 2022; 13:933416. [PMID: 36299576 PMCID: PMC9590451 DOI: 10.3389/fgene.2022.933416] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 07/28/2022] [Indexed: 11/13/2022] Open
Abstract
High incidence of chronic otitis media is associated with human craniofacial syndromes, suggesting that defects in the formation of the middle ear and associated structures can have a knock-on effect on the susceptibility to middle ear inflammation. Patients with branchio-oto-renal (BOR) syndrome have several defects in the ear leading to both sensorineural and conductive hearing loss, including otitis media. 40% of BOR syndrome cases are due to Eya1 haploinsufficiency, with mouse models affecting Eya1, mimicking many of the defects found in patients. Here, we characterize the onset, consequences, and underlying causes of chronic otitis media in Eya1 heterozygous mice. Cavitation defects were evident in these mice from postnatal day (P)11 onwards, with mesenchyme around the promontory and attic regions of the middle ear space. This mesenchyme was still prominent in adult Eya1 heterozygous mice, while the wild-type littermates had fully aerated ears from P14 onwards. MicroCT analysis highlighted a significantly smaller bulla, confirming the link between bulla size defects and the ability of the mesenchyme to retract successfully. Otitis media was observed from P14, often presenting unilaterally, resulting in hyperplasia of the middle ear mucosa, expansion of secretory cells, defects in the motile cilia, and changes in basal epithelial cell markers. A high incidence of otitis media was identified in older mice but only associated with ears with retained mesenchyme. To understand the impact of the environment, the mouse line was rederived onto a super-clean environment. Cavitation defects were still evident at early stages, but these generally resolved over time, and importantly, no signs of otitis media were observed at 6 weeks. In conclusion, we show that a small bulla size is closely linked to defects in cavitation and the presence of retained mesenchyme. A delay in retraction of the mesenchyme predates the onset of otitis media, making the ears susceptible to its development. Early exposure to OM appears to exacerbate the cavitation defect, with mesenchyme evident in the middle ear throughout the animal’s life. This highlights that permanent damage to the middle ear can arise as a consequence of the early onset of OM.
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Azar A, Bhutta MF, Del-Pozo J, Milne E, Cheeseman M. Trans-cortical vessels in the mouse temporal bulla bone are a means to recruit myeloid cells in chronic otitis media and limit peripheral leukogram changes. Front Genet 2022; 13:985214. [PMID: 36246635 PMCID: PMC9555619 DOI: 10.3389/fgene.2022.985214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 08/29/2022] [Indexed: 11/13/2022] Open
Abstract
Chronic otitis media, inflammation of the middle ear, is a sequel to acute otitis media in ∼8% of children. Chronic otitis media with effusion is the most common cause of childhood deafness and is characterised by effusion of white blood cells into the auditory bulla cavity. Skull flat bones have trans-cortical vessels which are responsible for the majority of blood flow in and out of the bone. In experimental models of stroke and aseptic meningitis there is preferential recruitment of myeloid cells (neutrophils and monocytes) from the marrow in skull flat bones. We report trans-cortical vessels in the mouse temporal bone connect to the bulla mucosal vasculature and potentially represent a means to recruit myeloid cells directly into the inflamed bulla. The mutant mouse strains Junbo (MecomJbo/+) and Jeff (Fbxo11Jf/+) develop chronic otitis spontaneously; MecomJbo/+ mice have highly cellular neutrophil (90%) rich bulla exudates whereas Fbxo11Jf/+ mice have low cellularity serous effusions (5% neutrophils) indicating differing demand for neutrophil recruitment. However we found peripheral leukograms of MecomJbo/+ and Fbxo11Jf/+ mice are similar to their respective wild-type littermate controls with healthy bullae and infer preferential mobilization of myeloid cells from temporal bulla bone marrow may mitigate the need for a systemic inflammatory reaction. The cytokines, chemokines and haematopoietic factors found in the inflamed bulla represent candidate signalling molecules for myeloid cell mobilization from temporal bone marrow. The density of white blood cells in the bulla cavity is positively correlated with extent of mucosal thickening in MecomJbo/+, Fbxo11Jf/+, and EdaTa mice and is accompanied by changes in epithelial populations and bone remodelling. In MecomJbo/+ mice there was a positive correlation between bulla cavity WBC numbers and total bacterial load. The degree of inflammation varies between contralateral bullae and between mutant mice of different ages suggesting inflammation may wax and wane and may be re-initiated by a new wave of bacterial infection. Clearance of white blood cells and inflammatory stimuli from the bulla cavity is impaired and this may create a pro-inflammatory feedback loop which further exacerbates otitis media and delays its resolution.
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Affiliation(s)
- Ali Azar
- Developmental Biology Division, Roslin Institute and The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Mahmood F. Bhutta
- Brighton and Sussex Medical School, Brighton, United Kingdom
- Department of ENT, Royal Sussex County Hospital, Brighton, United Kingdom
| | - Jorge Del-Pozo
- Veterinary Pathology, The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Elspeth Milne
- Veterinary Pathology, The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Michael Cheeseman
- Developmental Biology Division, Roslin Institute and The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, Scotland, United Kingdom
- Division of Pathology, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, Scotland, United Kingdom
- Centre for Comparative Pathology, Division of Pathology, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, Scotland, United Kingdom
- *Correspondence: Michael Cheeseman,
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Abstract
ABSTRACT
Within the developing head, tissues undergo cell-fate transitions to shape the forming structures. This starts with the neural crest, which undergoes epithelial-to-mesenchymal transition (EMT) to form, amongst other tissues, many of the skeletal tissues of the head. In the eye and ear, these neural crest cells then transform back into an epithelium, via mesenchymal-to-epithelial transition (MET), highlighting the flexibility of this population. Elsewhere in the head, the epithelium loses its integrity and transforms into mesenchyme. Here, we review these craniofacial transitions, looking at why they happen, the factors that trigger them, and the cell and molecular changes they involve. We also discuss the consequences of aberrant EMT and MET in the head.
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Affiliation(s)
- Natalie J. Milmoe
- Centre for Craniofacial and Regenerative Biology, King's College London, London SE1 9RT, UK
| | - Abigail S. Tucker
- Centre for Craniofacial and Regenerative Biology, King's College London, London SE1 9RT, UK
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Del-Pozo J, MacIntyre N, Azar A, Glover J, Milne E, Cheeseman M. Chronic otitis media is initiated by a bulla cavitation defect in the FBXO11 mouse model. Dis Model Mech 2019; 12:12/3/dmm038315. [PMID: 30898767 PMCID: PMC6451434 DOI: 10.1242/dmm.038315] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 02/25/2019] [Indexed: 12/20/2022] Open
Abstract
Auditory bulla cavitation defects are a cause of otitis media, but the normal cellular pattern of bulla mesenchyme regression and its failure are not well understood. In mice, neural-crest-derived mesenchyme occupies the bulla from embryonic day 17.5 (E17.5) to postnatal day 11 (P11) and then regresses to form the adult air-filled bulla cavity. We report that bulla mesenchyme is bordered by a single layer of non-ciliated epithelium characterized by interdigitating cells with desmosome cell junctions and a basal lamina, and by Bpifa1 gene expression and laminin staining of the basal lamina. At P11-P12, the mesenchyme shrinks: mesenchyme-associated epithelium shortens, and mesenchymal cells and extracellular matrix collagen fibrils condense, culminating in the formation of cochlea promontory mucosa bordered by compact non-ciliated epithelial cells. FBXO11 is a candidate disease gene in human chronic otitis media with effusion and we report that a bulla cavitation defect initiates the pathogenesis of otitis media in the established mouse model Jeff (Fbxo11Jf/+). Persistent mesenchyme in Fbxo11Jf/+ bullae has limited mesenchymal cell condensation, fibrosis and hyperplasia of the mesenchyme-associated epithelium. Subsequent modification forms fibrous adhesions that link the mucosa and the tympanic membrane, and this is accompanied by dystrophic mineralization and accumulation of serous effusion in the bulla cavity. Mouse models of bulla cavitation defects are important because their study in humans is limited to post-mortem samples. This work indicates new diagnostic criteria for this otitis media aetiology in humans, and the prospects of studying the molecular mechanisms of murine bulla cavitation in organ culture. Summary: FBXO11 is a candidate disease gene for otitis media in humans and the authors report that a bulla cavitation defect initiates otitis media in the Fbxo11Jf/+ mouse model.
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Affiliation(s)
- Jorge Del-Pozo
- Veterinary Pathology, The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh EH25 9RG, UK
| | - Neil MacIntyre
- Veterinary Pathology, The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh EH25 9RG, UK
| | - Ali Azar
- Developmental Biology Division, Roslin Institute and The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh EH25 9RG, UK
| | - James Glover
- Developmental Biology Division, Roslin Institute and The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh EH25 9RG, UK
| | - Elspeth Milne
- Veterinary Pathology, The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh EH25 9RG, UK
| | - Michael Cheeseman
- Developmental Biology Division, Roslin Institute and The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh EH25 9RG, UK .,Centre for Comparative Pathology & Division of Pathology, University of Edinburgh, Institute of Genetics & Molecular Medicine, Crewe Road, Edinburgh EH4 2XR, UK
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Rigueur D, Roberts RR, Bobzin L, Merrill AE. A requirement for Fgfr2 in middle ear development. Genesis 2018; 57:e23252. [PMID: 30253032 DOI: 10.1002/dvg.23252] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 09/17/2018] [Accepted: 09/18/2018] [Indexed: 12/12/2022]
Abstract
The skeletal structure of the mammalian middle ear, which is composed of three endochondral ossicles suspended within a membranous air-filled capsule, plays a critical role in conducting sound. Gene mutations that alter skeletal development in the middle ear result in auditory impairment. Mutations in fibroblast growth factor receptor 2 (FGFR2), an important regulator of endochondral and intramembranous bone formation, cause a spectrum of congenital skeletal disorders featuring conductive hearing loss. Although the middle ear malformations in multiple FGFR2 gain-of-function disorders are clinically characterized, those in the FGFR2 loss-of-function disorder lacrimo-auriculo-dento-digital (LADD) syndrome are relatively undescribed. To better understand conductive hearing loss in LADD, we examined the middle ear skeleton of mice with conditional loss of Fgfr2. We find that decreased auditory function in Fgfr2 mutant mice correlates with hypoplasia of the auditory bulla and ectopic bone growth at sites of tendon/ligament attachment. We show that ectopic bone associated with the intra-articular ligaments of the incudomalleal joint is derived from Scx-expressing cells and preceded by decreased expression of the joint progenitor marker Gdf5. Together, these results identify a role for Fgfr2 in development of the middle ear skeletal tissues and suggest potential causes for conductive hearing loss in LADD syndrome.
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Affiliation(s)
- Diana Rigueur
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, California.,Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Ryan R Roberts
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, California.,Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Lauren Bobzin
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, California.,Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Amy E Merrill
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, California.,Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
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Bluestone CD, Hebda PA, Alper CM, Sando I, Buchman CA, Stangerup SE, Felding JU, Swarts JD, Ghadiali SN, Takahashi H. 2. Eustachian Tube, Middle Ear, and Mastoid Anatomy; Physiology, Pathophysiology, and Pathogenesis. Ann Otol Rhinol Laryngol 2016; 194:16-30. [PMID: 15700932 DOI: 10.1177/00034894051140s105] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Charles D Bluestone
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh, Pennsylvania, USA
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Abstract
OBJECTIVES To develop normative data for wideband middle-ear reflectance in a newborn hearing-screening population and to compare test performance with 1-kHz tympanometry for prediction of otoacoustic emission (OAE) screening outcome. DESIGN Wideband middle-ear reflectance (using both tone and chirp stimuli from 0.2 to 6 kHz), 1-kHz tympanometry, and distortion-product (DP) OAEs were measured in 324 infants at two test sites. Ears were categorized into DP pass and DP refer groups. RESULTS Normative reflectance values were defined over various frequency regions for both tone and chirp stimuli in ambient pressure conditions, and for reflectance area indices integrated over various frequency ranges. Receiver operating characteristic analyses showed that reflectance provides the best discriminability of DP status in frequency ranges involving 2 kHz and greater discriminability of DP status than 1-kHz tympanometry. Repeated-measures analyses of variance established that (a) there were significant differences in reflectance as a function of DP status and frequency but not sex or ear; (b) tone and chirp stimulus reflectance values are essentially indistinguishable; and (c) newborns from two geographic sites had similar reflectance patterns above 1 kHz. Birth type and weight did not contribute to differences in reflectance. CONCLUSIONS Referrals in OAE-based infant hearing screening were strongly associated with increased wideband reflectance, suggesting middle-ear dysfunction at birth. Reflectance improved significantly during the first 4 days after birth with normalization of middle-ear function. Reflectance scores can be achieved within seconds using the same equipment used for OAE screening. Newborns with high reflectance scores at stage I screening should be rescreened within a few hours to a few days, because most middle-ear problems are transient and resolve spontaneously. If reflectance and OAE are not passed upon stage II screening, referral to an otologist for ear examination is suggested along with diagnostic testing. Newborns with normal reflectance and a refer result for the OAE screen should be referred immediately to an audiologist for diagnostic testing with threshold auditory brainstem response because of higher risk for permanent hearing loss.
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Affiliation(s)
- Lisa L Hunter
- Audiology Division, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229-3039, USA.
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Richter CA, Amin S, Linden J, Dixon J, Dixon MJ, Tucker AS. Defects in middle ear cavitation cause conductive hearing loss in the Tcof1 mutant mouse. Hum Mol Genet 2010; 19:1551-60. [DOI: 10.1093/hmg/ddq028] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Balci A, Sangun O, Okuyucu S, Karazincir S, Akoglu E, Altintas Y, Egilmez E. The prevalence and significance of incidental middle ear and mastoid cavity abnormalities on MRI in a pediatric population. Int J Pediatr Otorhinolaryngol 2008; 72:1849-54. [PMID: 18986714 DOI: 10.1016/j.ijporl.2008.09.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2008] [Revised: 08/29/2008] [Accepted: 09/04/2008] [Indexed: 10/21/2022]
Abstract
OBJECTIVE The purposes of this study were to determine the prevalence of abnormalities in the middle ear and mastoid cavity on the magnetic resonance imaging (MRI) in children and correlate the results with clinical data, tympanometric findings and paranasal sinus changes. MATERIALS AND METHODS A total of 85 consecutive pediatric patients for suspected non-inflammatory intracranial pathologies were prospectively examined. MRI was conducted for the suspected intracranial pathology. All patients were also examined by an otolaryngologist for otologic pathologies. A tympanometry examination was performed in patients prior to MRI scan. RESULTS In 23 (27.1%) of 85 (39 males, 46 females) children, MRI demonstrated middle ear and/or mastoid cavity abnormalities. MRI abnormalities of the middle ear and/or mastoid cavity were correlated with clinical data and tympanometric findings. CONCLUSIONS Incidental abnormal signal intensities in the middle ear and/or mastoid cavity are frequent in children, especially in first years of life. MRI will demonstrate incidental middle ear and mastoid cavity abnormalities seems to have clinical significance.
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Affiliation(s)
- Ali Balci
- Mustafa Kemal University, Faculty of Medicine, Department of Radiology, Antakya 31100, Hatay, Turkey.
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Lim DJ, Hermansson A, HellstrÖ SO, Hussl B, Alper CM, Uno Y, Andalibi A, Jung TTK, Bakaletz LO, Kawauchi H, Buchman CA, Kerschner J, Cayé-Thomasen P, Lin J, Chole RA, Merchant SN, Herman P, Lee HY, Kang SH, Paparella MM. 3. Animal Models; Anatomy and Pathology; Pathogenesis; Cell Biology and Genetics. Ann Otol Rhinol Laryngol 2005. [DOI: 10.1177/000348940511401s01] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Abstract
OBJECTIVE Persistent embryonic connective tissue has been considered to be a cause of chronic otitis media with effusion in neonates and of cholesteatoma in later life. As part of a study of pneumatization and resorption of embryonic connective tissue from the middle ear of pre- and postnatal infants, inflammatory processes of variable extents have been observed within the embryonic connective tissue. The aim of the present study was to characterize this inflammation and to detect patterns in its presence and distribution. MATERIAL AND METHODS Twenty fetal temporal bones obtained at 4-8 months of development and 31 temporal bones from children who died of sudden infant death syndrome aged < 1 year were studied to assess the inflammation within the middle ear cleft and specifically in the embryonic connective tissue. RESULTS Sixteen of 27 (59.3%) pre- and 10/31 (32.2%) postnatal specimens displayed a non-specific inflammatory lymphocytic infiltration without signs of bacterial infection or the presence of or reaction to amniotic contents. Eleven of 27 prenatal temporal bones (40.7%) and 16/31 (51.6%) postnatal specimens showed no evidence of histologic middle ear inflammation. The presence or absence of inflammation was independent of age. CONCLUSION Our observations indicate resorption of the embryonic connective tissue with individual variations indicating that genetic factors are responsible for the development of the middle ear spaces during the phases of development studied.
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Miura M, Sando I, Orita Y, Hirsch BE. Histopathologic study of the temporal bones and Eustachian tubes of children with cholesterol granuloma. Ann Otol Rhinol Laryngol 2002; 111:609-15. [PMID: 12126017 DOI: 10.1177/000348940211100708] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Six temporal bone-eustachian tube (ET) specimens with cholesterol granuloma (CG), obtained from 6 children 6 months to 15 years of age, were studied histopathologically to obtain further information about the pathogenesis of CG. We observed CG in the mastoid air cells in 5 ears, the mastoid antrum in 1 ear, the aditus ad antrum in 2 ears, and the epitympanum in 1 ear. All 6 cases exhibited a large amount of remaining mesenchyme that was in continuity with the hematopoietic bone marrow in the locations in which CG was present. All cases demonstrated otitis media with effusion and inflammation of the ET. Apparent morphological abnormalities of the ET and its associated structures, including hypoplastic ET cartilage and an abnormal tensor veli palatini muscle, were noted in 3 of the 6 cases. Furthermore, the posterior cartilaginous portion of the ET that includes its narrowest portion was completely filled with effusion in 2 of the 3 cases with the ET anomaly. The findings obtained were compared with data from age-matched control cases. Our results suggest that the source of erythrocytes in the remaining mesenchyme is the hematopoietic bone marrow. The pathogenesis of CG in children is likely promoted by ET dysfunction resulting in failure of ventilation of the middle ear.
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Affiliation(s)
- Makoto Miura
- Department of Otolaryngology, University of Pittsburgh School of Medicine, Pennsylvania 15213, USA
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