Patterns of Bone Damage in Patients With Chronic Middle Ear Inflammation.

BACKGROUND: Despite different etiologies, chronic otitis media involves the damaging and restructuring of bone tissue. The inflammatory process destroys elements of the ossicular chain, and bone lesions may appear that allow the development of otogenous complications. AIMS/OBJECTIVES: A correlation between the degree of damage to the ossicular chain as well as the bony walls of the middle ear and the type of chronic inflammatory lesions was sought. Destructive changes to bones were observed using scanning microscopy. MATERIAL AND METHODS: The removed damaged fragments of the ossicles were prepared for evaluation with a scanning microscope. Preparations were sputter-coated with a thin layer of gold and subsequently evaluated. RESULTS: Of 220 surgeries carried out in the discussed period, destruction of the middle ear bone walls, opening the way for the development of intracranial complications, was found in 27 patients. Most of them had ongoing chronic otitis media with granulation. CONCLUSIONS: (1) Bone loss of the skull base was observed more frequently in patients with chronic otitis media with granulation than with cholesteatoma. (2) In chronic otitis media with cholesteatoma, damage to the ossicular chain was observed significantly more frequently than in the case of otitis media with granulation.

Polymeric middle ear prosthesis enriched with silver nanoparticles - first clinical results.

OBJECTIVE: Otitis media is one of the most common illnesses which may cause ossicles destruction and conductive hearing loss. However, nowadays the damaged middle ear bones may be replaced by a partial or total ossicular replacement prosthesis. The main aim of this article was to confirm the proper functioning of the new middle ear prosthesis. METHODS: This work describes first clinical trials conducted on a group of three patients with the case of interrupted ossicles continuity and chronic otitis media. The clinical trials were performed according to permission No. 157/KBL/OIL2016. The patients were subjected to the bones chain reconstruction via implanting a bactericidal middle ear prosthesis called Otoimplant. The following preoperative and postoperative parameters have been evaluated: Air-Bone-Gap values, mean ABG values in different frequencies, bone and air conductivity, speech audiometry and microbiological assessment. The patients' recovery was observed according to the study protocol on the 7th day and 1, 3, 6 and 12 months after the surgery. RESULTS: Audiological tests revealed that the mean Air-Bone-Gap was reduced by 36% in all the patients after 1 year. No bacteria or fungi were found in the middle ear spaces. CONCLUSIONS: Results confirm the bactericidal efficacy and hearing improvement of the Otoimplant.

A Review of Surgical Nuances and Outcomes of the Reverse Stapedotomy.

The stapes surgery has evolved through different eras of technical and technological development. The current standard of care is creating a stapedotomy with piston placement, and both these aspects have multiple variations and show well-established technological advances. The conventional technique has been fairly standardized,and it offers gratifying results to both the surgeon and the patient. To overcome certain procedural risks and potential complications, the reversal of steps technique was developed and streamlined by Ugo Fisch in the early 1980s. Since its beginning, the technique has been adopted by various centers, and surgical outcomes have been demonstrated to be at par with the conventional technique, with a reduced risk of complications. The aim of the present review is to detail the various surgical nuances and outcomes of this particular technique in a comprehensive narrative manner.

Chronic otitis media is initiated by a bulla cavitation defect in the FBXO11 mouse model.

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.

Can floseal™ be applied safely during otologic surgery? Assessment of ototoxicity in a chinchilla animal model.

BACKGROUND: In otologic surgery good visualization is paramount, and patients with bleeding diatheses or who need to be anti-coagulated can present a significant challenge. Here, we determine whether Floseal™, a hemostatic matrix, is ototoxic in a validated animal model. METHODS: Nine chinchillas housed in the animal care facilities of the Montreal Children's Hospital Research Institute were used for the study. After a myringotomy incision was made in each tympanic membrane, baseline auditory brainstem response measurements were performed at 8, 20, and 25 kHz. In each animal one ear was randomized to receive Floseal™ to the middle ear cavity, whereas the other ear served as the control and received 0.9% sodium chloride. Outcome measures included early (day 7) and late (day 30) auditory brainstem response, clinical evidence of facial nerve or vestibular disturbance and histological evidence of ototoxity. RESULTS: There was no significant hearing threshold shift on auditory brainstem response across all tested frequencies for both experimental and control ear. No animals receiving Floseal™ developed facial or vestibular nerve dysfunction and there was no histological evidence of ototoxicity. CONCLUSION: Based on the preliminary ototoxicity assessment on nine chinchillas, transtympanic Floseal™ does not appear to be ototoxic. More studies are warranted to assess the safety and applicability of the product in humans.

Autologous human nasal epithelial cell sheet using temperature-responsive culture insert for transplantation after middle ear surgery.

Postoperative mucosal regeneration of the middle ear cavity and the mastoid cavity is of great importance after middle ear surgery. However, the epithelialization of the mucosa in the middle ear is retarded because chronic inflammation without epithelialization aggravates gas exchange and clinical function. These environmental conditions in the middle ear lead to postoperative retraction and adhesion of the newly-formed tympanic membrane. Therefore, if the mucosa on the exposed middle ear bone surface can be rapidly regenerated after surgery, the surgical treatments for cholesteatoma and adhesive middle ear disease can potentially be improved. In this study, we successfully generated a cell sheet designed for the postoperative treatment of cholesteatoma. We used nasal cells to create an artificial middle ear mucosal cell sheet with a three-dimensional (3D) configuration similar to that of the middle ear mucosa. The sheets consisted of multi-layered mucosal epithelia and lower connective tissue and were similar to normal middle ear mucosa. This result indicates that tissue-engineered mucosal cell sheets would be useful to minimize complications after surgical operations in the middle ear and future clinical applications are expected. Copyright © 2015 John Wiley & Sons, Ltd.

Ectopic Mineralization and Conductive Hearing Loss in Enpp1asj Mutant Mice, a New Model for Otitis Media and Tympanosclerosis.

Otitis media (OM), inflammation of the middle ear, is a common cause of hearing loss in children and in patients with many different syndromic diseases. Studies of the human population and mouse models have revealed that OM is a multifactorial disease with many environmental and genetic contributing factors. Here, we report on otitis media-related hearing loss in asj (ages with stiffened joints) mutant mice, which bear a point mutation in the Enpp1 gene. Auditory-evoked brainstem response (ABR) measurements revealed that around 90% of the mutant mice (Enpp1asj/asj) tested had moderate to severe hearing impairment in at least one ear. The ABR thresholds were variable and generally elevated with age. We found otitis media with effusion (OME) in all of the hearing-impaired Enpp1asj/asj mice by anatomic and histological examinations. The volume and inflammatory cell content of the effusion varied among the asj mutant mice, but all mutants exhibited a thickened middle ear epithelium with fibrous polyps and more mucin-secreting goblet cells than controls. Other abnormalities observed in the Enpp1 mutant mice include over-ossification at the round window ridge, thickened and over-calcified stapedial artery, fusion of malleus and incus, and white patches on the inside of tympanic membrane, some of which are typical symptoms of tympanosclerosis. An excessive yellow discharge was detected in the outer ear canal of older asj mutant mice, with 100% penetrance by 5 months of age, and contributes to the progressive nature of the hearing loss. This is the first report of hearing loss and ear pathology associated with an Enpp1 mutation in mice. The Enpp1asj mutant mouse provides a new animal model for studying tympanosclerotic otitis and otitis media with effusion, and also provides a specific model for the hearing loss recently reported to be associated with human ENPP1 mutations causing generalized arterial calcification of infancy and hypophosphatemic rickets.

Middle ear mucosal regeneration with three-dimensionally tissue-engineered autologous middle ear cell sheets in rabbit model.

The likelihood of recurrent retraction and adhesion of newly formed tympanic membrane is high when middle ear mucosa is extensively lost during cholesteatoma and adhesive otitis media surgery. If rapid postoperative regeneration of the mucosa on the exposed bone surface can be achieved, prevention of recurrent eardrum adhesion and cholesteatoma formation, for which there has been no definitive treatment, can be expected. Suture-less transplantation of tissue-engineered mucosal cell sheets was examined immediately after the operation of otitis media surgery in order to quickly regenerate middle ear mucosa lost during surgery in a rabbit model. Transplantable middle ear mucosal cell sheets with a three-dimensional tissue architecture very similar to native middle ear mucosa were fabricated from middle ear mucosal tissue fragments obtained in an autologous manner from middle ear bulla on temperature-responsive culture surfaces. Immediately after the mucosa was resected from middle ear bone bulla inner cavity, mucosal cell sheets were grafted at the resected site. Both bone hyperplasia and granulation tissue formation were inhibited and early mucosal regeneration was observed in the cell sheet-grafted group, compared with the control group in which only mucosal removal was carried out and the bone surface exposed. This result indicates that tissue engineered mucosal cell sheets would be useful to minimize complications after the surgical operation on otitis media and future clinical application is expected.

Macroscopic description of the external and middle ear of paca (Cuniculus paca Linnaeus, 1766) / Descrição macroscópica da orelha externa e media da paca (Cuniculus paca Linnaeus, 1766)

Paca (Cuniculus paca), one of the largest rodents of the Brazilian fauna, has inherent characteristics of its species which can conribute as a new option for animal experimantation. As there is a growing demand for suitable experimental models in audiologic and otologic surgical research, the gross anatomy and ultrastructural ear of this rodent have been analyzed and described in detail. Fifteen adult pacas from the Wild Animals Sector herd of Faculdade de Ciências Agrárias e Veterinárias, Unesp-Jaboticabal, were used in this study. After anesthesia and euthanasia, we evaluated the entire composition of the external ear, registering and ddescribing the details; the temporal region was often dissected for a better view and detailing of the tympanic bulla which was removed and opened to expose the ear structures analyzed mascroscopically and ultrastructurally. The ear pinna has a triangular and concave shape with irregular ridges and sharp apex. The external auditory canal is winding in its path to the tympanic mebrane. The tympanic bulla is is on the back-bottom of the skull. The middle ear is formed by a cavity region filled with bone and membranous structures bounded by the tympanic membrane and the oval and round windows. The tympanic membrane is flat and seals the ear canal. The anatomy of the paca ear is similar to the guinea pig and from the viewpoint of experimental model has major advantages compared with the mouse ear.

A paca (Cuniculus paca), um dos maiores roedores da fauna brasileira, possui características inerentes à sua espécie que podem contribuir como uma nova opção de animal experimental; assim, considerando-se que há crescente busca por modelos experimentais apropriados para pesquisas audiológicas e otológica cirúrgicas foram analisados e descritos em detalhes a anatomia macroscópica e ultraestrutural da orelha desse roedor. Para o estudo, utilizaram-se 15 animais adultos provenientes do plantel do Setor de Animais Silvestres da Faculdade de Ciências Agrárias e Veterinárias, Unesp-Jaboticabal, Jaboticabal/SP. Após anestesia e eutanásia, avaliou-se toda a composição da orelha externa, registrando-se e descrevendo-se os detalhes, também se dissecou a região temporal para melhor visibilização e detalhamento da bula timpânica e estas foram removidas e abertas a fim de expor as estruturas da orelha, as quais foram analisadas, macroscopicamente e ultraestruturalmente. O pavilhão auricular apresenta forma triangular e côncava com cristas irregulares e ápice pontiagudo; o conduto auditivo externo é sinuoso em seu trajeto até a membrana timpânica; a bula timpânica encontra-se na parte posterior-inferior do crânio; a orelha média é formada por uma região cavitária preenchida por estruturas ósseas e membranosas. É delimitada pela membrana timpânica e as janelas redonda e oval, sendo a membrana timpânica de forma plana e que veda todo o conduto auditivo. A anatomia da orelha da paca é semelhante à da cobaia e do ponto de vista de modelo experimental apresenta grandes vantagens em comparação com a orelha do rato.

Morphology and ciliary motion of mucosa in the Eustachian tube of neonatal and adult gerbils.

The Eustachian tube is a small canal that connects the tympanic cavity with the nasal part of the pharynx. The epithelial lining of the Eustachian tube contains a ciliated columnar epithelium at the tympanic cavity and a pseudostratified, ciliated columnar epithelium with goblet cells near the pharynx. The tube serves to equalize air pressure across the eardrum and drains mucus away from the middle ear into the nasopharynx. Blockage of the Eustachian tube is the most common cause of all forms of otitis media, which is common in children. In the present study, we examined the epithelial lining of the Eustachian tube in neonatal and adult gerbils, with a focus on the morphological and functional development of ciliated cells in the mucosa. The length of the tube is ∼8.8 mm in adult gerbils. Scanning electron microscopy showed that the mucosal member near the pharyngeal side contains a higher density of ciliated cells and goblet cells than that near the tympanic side. The cilia beat frequency is 11 Hz. During development, the length of the Eustachian tube increased significantly between postnatal day 1 (P1) and P18. Scanning electron microscopy showed that the mucosa contained a high density of ciliated cells with a few goblet cells at P1. The density of ciliated cells decreased while the density of goblet cells increased during development. At P18, the mucosa appeared to be adult-like. Interestingly, the ciliary beat frequency measured from ciliated cells at P1 was not statistically different from that measured from adult animals. Our study suggests that the Eustachian tube undergoes significant anatomical and histological changes between P1 and P18. The tube is morphologically and functionally mature at P18, when the auditory function (sensitivity and frequency selectivity) is mature in this species.

Detection of bacterial biofilms in different types of chronic otitis media.

Biofilms are organized bacterial communities that may be homogeneous or heterogeneous. They play a significant role in the pathogenesis of chronic nasal sinusitis, chronic tonsillitis, cholesteatomas, and device-related infections. Despite this, few studies have been done that examine the presence of bacterial biofilms in tissues from patients with different types of COM or middle ear cholesteatomas. In the current study, we examined the presence of biofilms in surgical tissue specimens from humans with chronic ear infections using scanning electron microscopy (SEM). We hypothesize that bacterial biofilms present differently in patients with different types of chronic otitis media. Our results provide new insights regarding treatment of chronic otitis media. A prospective study was conducted in which middle ear tissues were obtained from 38 patients who underwent tympanoplasty and/or tympanomastoid surgery due to chronic ear infections. A total of 50 middle and mastoid tissue samples were processed for SEM analysis. In addition, 38 middle ear secretion specimens were obtained for routine bacterial culture analysis. Bacterial biofilms were present in 85 % (11 of 13) of patients with middle ear cholesteatoma, 92 % (12/13) of patients with chronic otitis suppurative media (CSOM), and 16 % of patients (2/12) with tympanic membrane perforation (TMP). Fungal biofilms were found in two cases of cholesteatoma. The positive coincidence rate between bacterial biofilms visualized by SEM and bacteria detected by culture was 82 %. Our findings suggest that bacterial biofilms are very common in CSOM and middle ear cholesteatomas. Positive bacterial cultures imply the presence of biofilm formation in CSOM and cholesteatomas. As such, our results provide new insights regarding treatment of chronic otitis media.

Establishment of cell lines from the human middle and inner ear epithelial cells.

The middle ear infection is the most common childhood infection. In order to elucidate the cell and molecular mechanisms involved in bacterial recognition and innate immune response, we have established a stable human middle ear cell line, which has contributed to the current knowledge concerning the molecular pathogenesis of the middle ear infection. The inner ear, a sensory organ responsible for hearing and balance, is filled with inner ear fluid, and disturbance of the fluid homeostasis results in dizziness and hearing impairment. It has been suggested that the endolymphatic sac (ES) may play a critical role in the fluid homeostasis of the inner ear. We have established a stable human ES cell line and are undertaking cell and molecular characterization of this cell line.

Sh3pxd2b mice are a model for craniofacial dysmorphology and otitis media.

Craniofacial defects that occur through gene mutation during development increase vulnerability to eustachian tube dysfunction. These defects can lead to an increased incidence of otitis media. We examined the effects of a mutation in the Sh3pxd2b gene (Sh3pxd2b(nee)) on the progression of otitis media and hearing impairment at various developmental stages. We found that all mice that had the Sh3pxd2b(nee) mutation went on to develop craniofacial dysmorphologies and subsequently otitis media, by as early as 11 days of age. We found noteworthy changes in cilia and goblet cells of the middle ear mucosa in Sh3pxd2b(nee) mutant mice using scanning electronic microscopy. By measuring craniofacial dimensions, we determined for the first time in an animal model that this mouse has altered eustachian tube morphology consistent with a more horizontal position of the eustachian tube. All mutants were found to have hearing impairment. Expression of TNF-α and TLR2, which correlates with inflammation in otitis media, was up-regulated in the ears of mutant mice when examined by immunohistochemistry and semi-quantitative RT-PCR. The mouse model with a mutation in the Sh3pxd2b gene (Sh3pxd2b(nee)) mirrors craniofacial dysmorphology and otitis media in humans.

Aggressive low grade middle ear adenocarcinoma with multiple recurrences: a case report.

BACKGROUND: Primary tumours of the middle ear are much less commonly encountered in clinical practice than non neoplastic lesions. Middle ear adenocarcinoma is a very rare, locally invasive neoplasm assumed to arise from the middle ear mucosa. Because the natural course and clinical behavior of this neoplasm are far from established, the sporadic reports of such cases continue to provide basis for better understanding. CASE DESCRIPTION: A case of low grade adenocarcinoma of the middle ear is described in details with regard to its clinical presentation, radiological findings, histopathological, immunohistochemical and ultrastructural findings. The tumour recurred four times.

Detection of bacteria in healthy middle ears during cochlear implantation.

OBJECTIVE: To assess whether free-living and/or biofilm bacteria are present in the putative sterile middle ear cavity before insertion of the electrode array during cochlear implantation. DESIGN: Prospective study. SETTING: Tertiary academic hospital. PATIENTS: The study included 45 healthy children (with or without a history of otitis media) undergoing cochlear implantation. INTERVENTIONS: Transmission electron microscopy or scanning electron microscopy was used to detect the presence of bacteria. MAIN OUTCOME MEASURE: Presence of both free-living bacteria and biofilm bacteria on the epithelial surface of biopsy specimens of middle ear mucosa. RESULTS: A majority of all mucosal specimens from clinically healthy tympanic cavities displayed inflammatory areas as well as dispersed, nonmatrix-enclosed bacteria. Also, rarely, fragments of biofilms were found. CONCLUSIONS: The presence of bacteria in the tympanic cavity, which is generally assumed to be sterile in healthy individuals, may provide an explanation for infectious complications after cochlear implantation. However, the possibility that the electrode array of a cochlear implant will actually become contaminated during insertion is unlikely because of the small amounts and dispersed presence of bacteria, which may account for the relatively low incidence of infectious complications after cochlear implantation.

Conhecimento da anatomia da orelha de cobaias e ratos e sua aplicação na pesquisa otológica básica / Understanding the anatomy of ears from guinea pigs and rats and its use in basic otologic research

O uso de mostras animais é importante na pesquisa otológica e o conhecimento da anatomia de sua orelha permite sua utilização adequada. OBJETIVO: Estudar a anatomia da orelha da cobaia e do rato por microscopia óptica de luz (MOL) e microscopia eletrônica de varredura (MEV) e suas vantagens anatômicas na pesquisa otológica básica. MATERIAL E MÉTODO: Os ossos temporais, as bulas timpânicas e cócleas de três cobaias e ratos albinos foram fotografados e analisados ao MOL e MEV. RESULTADOS: O rato não é tão simples de manipular como a cobaia, e freqüentemente apresenta otite média. O rato apresenta uma junção frágil da bula timpânica, duas e meia espiras na cóclea e a membrana timpânica não veda todo o conduto auditivo externo. A cobaia possui uma bula inteiriça, martelo e bigorna fundidos e três e meia espiras na cóclea. Pela MEV a cobaia e o rato possuem Membrana Tectória, Membrana de Raissner e o Órgão de Corti. As Células de Hensen estão presentes somente na cobaia. CONCLUSÃO: A cobaia foi considerada de fácil manipulação para a microdissecção, pelo tamanho e rigidez do osso temporal, e para experimentos cirúrgicos envolvendo o estribo, janela oval e a membrana timpânica. Pela MEV nota-se semelhança entre cobaia e rato, podendo ambos serem utilizados em estudos da orelha interna.

The use of animal samples is important in otologic research and understanding the anatomy of their ears help make proper use of them in research projects. AIM: to study guinea pig's and rat's ears under light microscopy(LM) and scanning electron microscopy(SEM) and understand their anatomical advantages in basic otologic research. MATERIALS AND METHODS: The temporal bones, tympanic bullas and cochleas from three albino guinea pigs and rats were photographed and analyzed under LM and SEM. RESULTS: Rats aren't as simple to handle as guinea pigs, and often present with otitis media. Rats have a fragile junction of the tympanic bulla, two and half turns in the cochlea, and their tympanic membranes do not seal off the entire external auditory canal. Guinea pigs have full bullas, their incus and malleus are fused and they have three and half cochlear turns. Under SEM, guinea pigs and rats have Tectori Membrane, Raissner's Membrane and the Organ of Corti. Only guinea pigs have Hensen's Cells. CONCLUSION: Guinea pigs were considered easy to handle for microdissection purposes because of the size and robustness of their temporal bones, and for surgical experiments involving the stapes, the oval window and the tympanic membrane. Under SEM there are similarities guinea pigs and rats, and both can be used in inner ear studies.

Estudio morfológico del oído medio e interno de la Chinchilla laniger / Morphological study of the middle and internal ear of Chinchilla laniger

Introducción: La Chinchilla laniger, roedor originario de la Cordillera de Los Andes, ha sido utilizada como modelo de investigación otológica por más de 40 años. Sin embargo, no existe un estudio anatómico e histológico detallado del oído de este animal. La mayoría de las investigaciones se han desarrollado en neurofisiología de la audición. Objetivos: Describir macroscópica y microscópicamente el oído medio e interno de la Chinchilla laniger. Material y método: Estudio realizado en cinco chinchillas adultas (previa aprobación del Comité de Bioética sobre la Investigación en Animales). Macroscopía: Se realizó una cirugía vía conducto auditivo externo y se estudió también con una tomografía computada de oído s. Microscopía: Disección, fijación e inclusión en parafina. Tinción con hematoxilina-eosina. Resultados: Vía conducto auditivo externo se realiza un colgajo timpanomeatal similar al de estapedectomía. Se accede a la caja timpánica por el cuadrante posterosuperior Se observa que el martillo presenta un delgado mango unido verticalmente al tímpano. Presenta una cabeza con un gran proceso anterior en vez de ligamento timpanomaleolar anterior. Su cabeza se une al yunque, fusionándose. El proceso lenticular del yunque se une a un delgado estribo, en el cual se observa el vestigio de la arteria estapedial, entre las cruras. El promontorio es visible fácilmente dado su tamaño y prominencia. La ventana oval se encuentra levemente más superoanterior que la ventana redonda. La cóclea da 3 y media vueltas sobre el modiolo. El órgano de Corti, sáculo, utrículo y crista ampularis se identificaron en los cortes histológicos. Conclusiones: El estudio morfológico detallado de un modelo de investigación como la chinchilla es imprescindible para el desarrollo de nuevos estudios en audición.

Introduction: Chinchilla laniger is a rodent that has been used as a model of ear research for more than 40 years; nevertheless, a macroscopic and microscopic detailed study of the ear in this animal is lacking. Purposes: Jo describe the anatomy and histology of the middle and inner ear of Chinchilla laniger. Materials and methods: Five adult chinchillas were used in this study. The macroscopic study was made with a computed tomography of the ear and then dissection under a microscope. For the microscopic study ears were dissected, fixed, decalcified, included in paraffin and then sectioned and stained with hematoxylin-eosin. Results: A tympanomeatal flap was made via the external acoustic meatus, similar to a stapedectomy The tympanic cavity was accessed through the posterosuperior quadrant to examine the malleus. A thin manubrium attached vertically to the eardrum could be observed. The malleus head is characterized by a large anterior process, instead of the anterior tympanomallear ligament, and it was fused to the incus. The lenticular process of the latter joined a thin stapedius, in which the vestige of the stapedial artery was observed (between the cruras). The promontory was visible easily because of its size and prominence. The oval window was located more superoanterior than the round window. The cochlea gave 31/2 turns around the modiolus. The organ of Corti, saccule, utricle and ampullary crest were identified in the histological sections. Conclusions: The ear of Chinchilla laniger is similar to the human ear supporting its use as a model in ear research. The study of the ear specially the cochlea, is difficult and needs great dedication in order to obtain good results.

The role of chronic infection in children with otitis media with effusion: evidence for intracellular persistence of bacteria.

OBJECTIVE: Demonstrate mucosal bacterial infection in children with otitis media with effusion (OME). STUDY DESIGN AND SETTING: Middle ear mucosal biopsies from 11 children with OME were examined for bacteria utilizing transmission electron microscopy. This was correlated with standard culture and polymerase chain reaction (PCR) of middle ear effusions. RESULTS: Gram-positive coccal bacteria were demonstrated in middle ear mucosal epithelial cells of 4 of 11 (36%) children. Morphological appearance of bacteria and detection of pneumolysin DNA by PCR in middle ear fluid suggests a role for persistent intracellular infection with Streptococcus pneumoniae and other gram-positive cocci in some cases of OME. CONCLUSION: Intracellular bacterial infection of middle ear mucosal epithelial cells in children with OME may be an important mechanism for bacterial persistence, and contribute to inflammation and mucus production in the pathogenesis of this condition. SIGNIFICANCE: Persistent intracellular infection is a novel paradigm for OME pathogenesis in children and may influence antibiotic effectiveness in treatment of this condition.

Secretory meningioma of the middle ear: a light microscopic, immunohistochemical and ultrastructural study of one case.

A 66-year-old woman was referred with left hearing loss. A probable diagnosis of left secretory otitis media with effusion was formulated. A left myringotomy was performed to remove hyperplastic hard tissue from the tympanic cavity. A high resolution CT scan of the temporal bone disclosed a soft-tissue mass completely involving the mastoid and tympanic cavity, surrounding the ossicular chain which appeared spared with no signs of infiltration. The histopathologic, immunohistochemical and ultrastructural response was secretory meningioma, a rare variant of conventional meningothelial meningioma in atypical sites.

Middle ear mucosa regeneration by grafting of artificial mucosa.

CONCLUSION: Artificial middle ear mucosa (AMEM), a sheet of mucosal cells grown on collagen gel populated with fibroblasts, is useful as graft material that is able to promote mucosal regeneration after middle ear surgery. OBJECTIVES: Regeneration of the middle ear mucosa and pneumatization of the mastoid cavity is critical for good prognosis. We examined whether implantation of AMEM into damaged middle ear cavity would promote mucosal regeneration. MATERIALS AND METHODS: AMEM was prepared as described previously using epithelial cells and fibroblasts isolated from the rabbit middle ear. We implanted AMEM into rabbit middle ear from which mucosa had been surgically removed and evaluated its histological and functional recovery 8 weeks later. Three other groups were used for comparison: a normal control group, a mucosa-eliminated group, and a collagen-implanted group. RESULTS: AMEM grew to be morphologically similar to the native middle ear mucosa. Electron microscope studies showed that implanted AMEM has basal lamina and cilia. AMEM implantation suppressed bone hyperplasia and granulation, leading to better mucosal regeneration. Mucosal gas exchange was also significantly improved after implantation.