Management of Chronic Middle Ear Effusion

Management of chronic middle ear effusion must center around the reestablishment of normal eustachian tube function. If fluid does not clear with medical management, aspiration becomes necessary. A prosthetic eustachian tube is placed in the tympanic membrane in order to artificially ventilate the middle ear space while primary etiologic factors are being corrected.Unless recurrent or chronic ear disease of this nature is diligently treated, progressive damage may bring about irreversible hearing loss and the potentially dangerous disease, cholesteatoma of the ear.     

Levator veli palatini muscle and eustachian tube function

Thirty previously unoperated patients with submucous cleft palate, occult submucous cleft palate, and unilateral congenital paralysis of the levator veli palatini muscle were examined. All patients were subjected to a comprehensive otoscopic, endoscopic, audiologic, and tympanometric evaluation. A correlation was made between levator veli palatini muscle anomalies, eustachian tube orifice anomalies, and middle ear ventilation and disorders. Normal middle ear ventilation was found in 23 patients. Negative middle ear pressure that consequently normalized following treatment of coexisting sinusitis was found in 3 patients. Only in 4 patients was chronic middle ear disease found. In one of them, middle ear effusion disappeared following successful treatment of sinusitis. Our conclusion is that the levator veli palatini muscle has no significant function in the opening mechanism of the eustachian tube and must be considered as a velopharyngeal valve muscle only.     

Enzymatic Formation of G-Group Aflatoxins and Biosynthetic Relationship between G- and B-Group Aflatoxins

We detected biosynthetic activity for aflatoxins G₁ and G₂ in cell extracts of Aspergillus parasiticus NIAH-26. We found that in the presence of NADPH, aflatoxins G₁ and G₂ were produced from O-methylsterigmatocystin and dihydro-O-methylsterigmatocystin, respectively. No G-group aflatoxins were produced from aflatoxin B₁, aflatoxin B₂, 5-methoxysterigmatocystin, dimethoxysterigmatocystin, or sterigmatin, confirming that B-group aflatoxins are not the precursors of G-group aflatoxins and that G- and B-group aflatoxins are independently produced from the same substrates (O-methylsterigmatocystin and dihydro-O-methylsterigmatocystin). In competition experiments in which the cell-free system was used, formation of aflatoxin G₂ from dihydro-O-methylsterigmatocystin was suppressed when O-methylsterigmatocystin was added to the reaction mixture, whereas aflatoxin G₁ was newly formed. This result indicates that the same enzymes can catalyze the formation of aflatoxins G₁ and G₂. Inhibition of G-group aflatoxin formation by methyrapone, SKF-525A, or imidazole indicated that a cytochrome P-450 monooxygenase may be involved in the formation of G-group aflatoxins. Both the microsome fraction and a cytosol protein with a native mass of 220 kDa were necessary for the formation of G-group aflatoxins. Due to instability of the microsome fraction, G-group aflatoxin formation was less stable than B-group aflatoxin formation. The ordA gene product, which may catalyze the formation of B-group aflatoxins, also may be required for G-group aflatoxin biosynthesis. We concluded that at least three reactions, catalyzed by the ordA gene product, an unstable microsome enzyme, and a 220-kDa cytosol protein, are involved in the enzymatic formation of G-group aflatoxins from either O-methylsterigmatocystin or dihydro-O-methylsterigmatocystin.     

The occurrence of Mycoplasma arthritidis in the throat and middle ear of rats with chronic respiratory disease.

Twenty-three rats with chronic respiratory disease were examined for the presence of Mycoplasma arthritidis in the throat and middle ear. Samples were taken at necropsy and swabbed onto an agar medium. Morphologically typical colonies were subcultured and identified serologically. All of the rats showed evidence histopathologically of chronic respiratory disease, and typical M pulmonis colonies were isolated from 21 of 23. M arthritidis was isolated from 7 (30=) of the middle ears and 3 (13%) of the throats, confirming a previous observation of the occurrence of this organism in the middle ear of rats and also indicating it can be present in the throat.     

The multifunctional host defense peptide SPLUNC1 is critical for homeostasis of the mammalian upper airway

Otitis media (OM) is a highly prevalent pediatric disease caused by normal flora of the nasopharynx that ascend the Eustachian tube and enter the middle ear. As OM is a disease of opportunity, it is critical to gain an increased understanding of immune system components that are operational in the upper airway and aid in prevention of this disease. SPLUNC1 is an antimicrobial host defense peptide that is hypothesized to contribute to the health of the airway both through bactericidal and non-bactericidal mechanisms. We used small interfering RNA (siRNA) technology to knock down expression of the chinchilla ortholog of human SPLUNC1 (cSPLUNC1) to begin to determine the role that this protein played in prevention of OM. We showed that knock down of cSPLUNC1 expression did not impact survival of nontypeable Haemophilus influenzae, a predominant causative agent of OM, in the chinchilla middle ear under the conditions tested. In contrast, expression of cSPLUNC1 was essential for maintenance of middle ear pressure and efficient mucociliary clearance, key defense mechanisms of the tubotympanum. Collectively, our data have provided the first in vivo evidence that cSPLUNC1 functions to maintain homeostasis of the upper airway and, thereby, is critical for protection of the middle ear.     

化脓性中耳炎病原菌感染的研究进展

化脓性中耳炎是耳鼻喉科临床常见疾病,可导致听力下降、鼓膜充血、鼓膜穿孔、耳鸣、耳痛及流脓等。化脓性中耳炎主要由微生物进入中耳引起感染,使中耳黏膜发生化脓性病变,且不同患者感染的病原菌不同。本文从化脓性中耳炎的发病机制、病原菌及其耐药性和治疗方法等几个方面进行综述,以期为临床化脓性中耳炎的诊断及合理用药提供参考。     

The structure of the middle ear epithelium of the rat and the effect of Eustachian tube obstruction

Summary The middle ear cavity of the rat is lined with ciliated and squamous epithelium. The arrangement of the ciliated cells, interspersed with secretory cells, in distinct tracts and their continuity with the ciliated epithelium of the Eustachian tube, suggests the existence of a mucociliary transport system for cleaning the middle ear cleft. The secretory cells produce either neutral or sulphated glycoproteins, dependent on their location. In addition to these secretions, the epithelium of the lower part of the Eustachian tube is bathed with secretory products of seromucous glands.Also in the areas with squamous epithelium, numerous small secretory cells, the character of which is only identifiable with the electronmicroscope, are present. It is concluded that the middle ear lining can be considered as a locally modified respiratory epithelium.Blockade of the mucociliary transport system, supposedly a crucial aetiological factor in secretory otitis media, by obstruction of the Eustachian tube, induces pathogenic behaviour of microorganisms normally present in the middle ear. This results in either a transient or a longstanding infective middle ear disease, associated with a large variety of changes of the mucosa, especially with respect to the secretory activity.The data obtained indicate that the increased secretory activity encountered in secretory otitis media cannot be attributed to the isolated effect of tubal occlusion, but rather to an infective process.     

3D finite element model of the chinchilla ear for characterizing middle ear functions

Chinchilla is a commonly used animal model for research of sound transmission through the ear. Experimental measurements of the middle ear transfer function in chinchillas have shown that the middle ear cavity greatly affects the tympanic membrane (TM) and stapes footplate (FP) displacements. However, there is no finite element (FE) model of the chinchilla ear available in the literature to characterize the middle ear functions with the anatomical features of the chinchilla ear. This paper reports a recently completed 3D FE model of the chinchilla ear based on X-ray micro-computed tomography images of a chinchilla bulla. The model consisted of the ear canal, TM, middle ear ossicles and suspensory ligaments, and the middle ear cavity. Two boundary conditions of the middle ear cavity wall were simulated in the model as the rigid structure and the partially flexible surface, and the acoustic-mechanical coupled analysis was conducted with these two conditions to characterize the middle ear function. The model results were compared with experimental measurements reported in the literature including the TM and FP displacements and the middle ear input admittance in chinchilla ear. An application of this model was presented to identify the acoustic role of the middle ear septa—a unique feature of chinchilla middle ear cavity. This study provides the first 3D FE model of the chinchilla ear for characterizing the middle ear functions through the acoustic-mechanical coupled FE analysis.     

Barotrauma during air travel: predictions of a mathematical model.

Middle ear barotrauma during flight is a painful disorder experienced by passengers who cannot properly regulate their middle ear pressure in response to the changing cabin pressures during ascent and descent. Previous reports emphasized the important role of poor eustachian tube function in disease pathogenesis but paid little attention to other moderating factors. Here we describe a mathematical model of middle ear pressure regulation and simulate the pressure response to the changes in cabin pressure experienced over typical flights. The results document buffering mechanisms that decrease the requisite efficiency of active, muscle-assisted eustachian tube opening for disease-free flight. These include the relative difference between destination and departure elevations and the ratio of maximum tympanic membrane volume displacement to middle ear volume, where greater absolute values require lesser efficiencies for disease-free flight. Also, the specific type of functional deficit is important since ears with a completely obstructed eustachian tube can be less susceptible to barotrauma than those with a eustachian tube that passively opens but fails to dilate in response to muscle activity. These buffering systems can explain why some children and adults with poor eustachian tube function do not experience middle ear barotrauma.     

Study of middle ear disease using tympanometry in general practice.

Tympanometry was used to provide evidence of middle ear effusions in a prospective study of middle ear disease in 264 children aged 3 months to 6 years in general practice. Adequate measurements on both ears were obtained in 220 children, of whom 68 (31%) had evidence of middle ear effusion in one ear (29 children) or both ears (39 children) at entry to the study. In 28 (42%) of the 68 children persistence of the tympanometric findings was recorded for at least three months. Children of European descent were more likely to have evidence of middle ear effusion at the initial examination compared with African and West Indian children, as were those children whose siblings had a positive history of otitis media compared with those whose siblings had no such history. Children under 3 years were more likely to have evidence of an effusion than older children. Middle ear effusion as shown by tympanometry was not associated with a previous history of otitis media in the child but was associated with recent symptoms of respiratory infection or otalgia. A previous consultation for otitis media was, however, strongly associated with a greater likelihood of a consultation for otitis media during the follow up period. Comparing evidence of effusion by tympanometry with that by pneumatic otoscopy showed that using the appearance of the eardrum alone the sensitivity of otoscopy was 55%; the addition of mobility improved the sensitivity to 76% with little reduction in specificity. Further studies on populations using tympanometry are needed to determine the natural history, aetiology, and indications for referring children with middle ear effusion.     

Nucleolus organizer and N-band distribution in morphologic and fluorescence variants of human chromosomes

Summary Three cases of morphologic variants of human D- or G-group chromosomes have been studied by N- and Ag-AS banding techniques. The results confirm our previous findings about the localization of nucleolus organizers on the secondary constrictions of acrocentric chromosomes. Preliminary results on the distribution and number of N bands in D- and G-group chromosomes with morphologic and fluorescence variants are reported     

Respiratory syncytial virus promotes Moraxella catarrhalis-induced ascending experimental otitis media

Otitis media (OM) is a polymicrobial disease wherein prior or concurrent infection with an upper respiratory tract virus plays an essential role, predisposing the middle ear to bacterial invasion. In episodes of acute bacterial OM, respiratory syncytial virus (RSV) is the most commonly isolated virus and thus serves as an important co-pathogen. Of the predominant bacterial agents of OM, the pathogenesis of disease due to Moraxella catarrhalis is the least well understood. Rigorous study of M. catarrhalis in the context of OM has been significantly hindered by lack of an animal model. To bridge this gap, we assessed whether co-infection of chinchillas with M. catarrhalis and RSV would facilitate ascension of M. catarrhalis from the nasopharynx into the middle ear. Chinchillas were challenged intranasally with M. catarrhalis followed 48 hours later by intranasal challenge with RSV. Within 7 days, 100% of nasopharynges were colonized with M. catarrhalis and homogenates of middle ear mucosa were also culture-positive. Moreover, within the middle ear space, the mucosa exhibited hemorrhagic foci, and a small volume of serosanguinous effusion was present in one of six ears. To improve upon this model, and based on epidemiologic data, nontypeable Haemophilus influenzae (NTHI) was included as an additional bacterial co-pathogen via intranasal administration four days before M. catarrhalis challenge. With this latter protocol, M. catarrhalis was cultured from the nasopharynx and middle ear homogenates of a maximum of 88% and 79% animals, respectively, for up to 17 days after intranasal challenge with M. catarrhalis. Additionally, hemorrhagic foci were observed in 79% of middle ears upon sacrifice. Thus, these data demonstrated that co-infection with RSV and NTHI predisposed to M. catarrhalis-induced ascending experimental OM. This model can be used both in studies of pathogenesis as well as to investigate strategies to prevent or treat OM due to M. catarrhalis.     

A REVIEW OF OPERATIONS ON THE TEMPORAL BONE

The majority of temporal bone operations are performed for treatment of acute or chronic middle ear and mastoid infection, otosclerosis and perforations of the tympanic membrane.Far from being a thing of the past, temporal bone surgery is an expanding field in the antibiotic age.Since treatment with antibiotics may temporarily allay the symptoms of serious disease of the ear, great care must be taken in examination of patients with a suspicious history.     

Role of the pro-inflammatory cytokines tumor necrosis factor-alpha,interleukin-1 beta,interleukin-6 and interleukin-8 in the pathogenesis of the otitis media with effusion

Inflammation in the middle ear mucosa, caused usually by bacterial and viral pathogens, is the primary event in the middle ear predisposing the development of otitis media with effusion (OME). Numerous inflammatory mediators have been identified in OME. However, cytokines play a central role as initiators, mediators and regulators of middle ear inflammation and subsequent molecular-pathological processes in middle ear tissues, leading to histopathological changes in the middle ear cavity and the pathogenesis of OME. In this article, we aim to present an overview of current research developments in the pro-inflammatory cytokine involvement in the aetiology of otitis media with effusion.     

Cholesteatoma of the Ear

Cholesteatoma is a hazardous condition because of the erosion and tissue destruction, which result in deafness, and the complications which threaten life. Early diagnosis and treatment provide the best opportunity for eradication of the disease and preservation of hearing.The patient usually complains of intermittent or persistent ear drainage and of diminished hearing acuity. Close examination of the tympanic membrane reveals a perforation, which at times may be quite small, with epithelial extension into the middle ear space. In most instances surgical intervention is necessary for eradication of the disease.     

Passive smoking,salivary cotinine concentrations,and middle ear effusion in 7 year old children.

OBJECTIVE--To assess the contribution of passive exposure to tobacco smoke to the development of middle ear underpressure and effusion. DESIGN--Cross sectional observational study. SETTING--One third of the primary schools in Edinburgh. SUBJECTS--892 Children aged 6 1/2 to 7 1/2 were examined, and satisfactory tympanograms were obtained in 872. Results of assay of salivary cotinine concentrations were available for 770 children, and satisfactory tympanograms were available for 736 of these. END POINT--Correlation of the prevalence of middle ear underpressure and effusion with concentrations of the marker of nicotine, cotinine, in the saliva of the children. MEASUREMENTS AND MAIN RESULTS--Middle ear pressure and compliance were measured in both ears by impedance tympanometry. Salivary cotinine concentrations were assayed by gas-liquid chromatography. Cotinine concentrations increased with the number of smokers in the household. Girls had higher concentrations than boys, and children living in rented housing had higher concentrations than those living in housing owned by their parents. There was a trend towards more abnormal tympanometric findings with increasing cotinine concentration, the odds ratio for a doubling of the cotinine concentration being 1.14 (95% confidence interval 1.03 to 1.27). After adjustment for the sex of the child and housing tenure the odds ratio for a doubling of the cotinine concentration was 1.13 (1.00 to 1.28). CONCLUSIONS--The results of this study are consistent with those of case-control studies of children attending for an operation to relieve middle ear effusion. They indicate that the disease should be added to the list of recognised hazards associated with passive smoking. About one third of the cases of middle ear effusion in this study were statistically attributable to exposure to tobacco smoke.     

Evolution of the middle ear apparatus in Talpid moles

The middle ear structures of eight species of mole in the family Talpidae (Mammalia: Eulipotyphla) were studied under light and electron microscopy. Neurotrichus, Parascalops, and Condylura have a simple middle ear cavity with a loose ectotympanic bone, ossicles of a "microtype" morphology, and they retain a small tensor tympani muscle. These characteristics are ancestral for talpid moles. Talpa, Scalopus, Scapanus, and Parascaptor species, on the other hand, have a looser articulation between malleus and ectotympanic bone and a reduced or absent orbicular apophysis. These species lack a tensor tympani muscle, possess complete bullae, and extensions of the middle ear cavity pneumatize the surrounding basicranial bones. The two middle ear cavities communicate in Talpa, Scapanus, and Parascaptor species. Parascaptor has a hypertrophied malleus, a feature shared with Scaptochirus but not found in any other talpid genus. Differences in middle ear morphology within members of the Talpidae are correlated with lifestyle. The species with middle ears closer to the ancestral type spend more time above ground, where they will be exposed to high-frequency sound: their middle ears appear suited for transmission of high frequencies. The species with derived middle ear morphologies are more exclusively subterranean. Some of the derived features of their middle ears potentially improve low-frequency hearing, while others may reduce the transmission of bone-conducted noise. By contrast, the unusual middle ear apparatus of Parascaptor, which exhibits striking similarities to that of golden moles, probably augments seismic sensitivity by inertial bone conduction.     

Study of age-related changes in Middle ear transfer function

Abstract

Osteoporosis (OP) is common with advancing age. Several studies have shown a strong correlation between OP and otosclerosis. However, no studies have investigated OP of the malleus, incus or stapes in the human middle ear, its effect on middle ear transfer function. Here, we investigate whether these three ossicles develop OP, and how this affects middle ear transfer function. The effect of OP on middle ear transfer function was investigated in simulations based on a finite element (FE) method. First, the FE model used in our previous study was refined, and optimized by introducing viscoelastic properties to selected soft tissues of the middle ear. Then, the FE model was used to simulate OP of the three ossicles and assess its influence on middle ear transfer function. Other possible age-related changes, such as stiffness of the joints or ligaments in the middle ear, were also investigated. The results indicated that OP of the ossicles could increase the high frequency displacement of both the umbo and stapes footplate (FP). However, the stiffness of the middle ear soft tissue can lead to the decrease of middle ear gain at lower frequencies. Furthermore, loosening of these joints or ligaments could increase displacement of the umbo and stapes FP. In conclusion, although age-related hearing loss is most commonly conceived of as sensorineural hearing loss (SNHL), we found that age-related changes may also include OP and changes in joint stiffness, but these will have little effect on middle ear transfer function in elderly people.     

Middle ear sample collection in the chinchilla

Use of the chinchilla as a model of middle ear infection in auditory research necessitates accessing the middle ear to collect samples or inoculate bacteria. This column describes a simple technique for middle ear access. The procedure is also useful for investigating and treating middle ear infections in chinchillas.     

Computer-integrated finite element modeling of human middle ear

 The objective of this study was to produce an improved finite element (FE) model of the human middle ear and to compare the model with human data. We began with a systematic and accurate geometric modeling technique for reconstructing the middle ear from serial sections of a freshly frozen temporal bone. A geometric model of a human middle ear was constructed in a computer-aided design (CAD) environment with particular attention to geometry and microanatomy. Using the geometric model, a working FE model of the human middle ear was created using previously published material properties of middle ear components. This working FE model was finalized by a cross-calibration technique, comparing its predicted stapes footplate displacements with laser Doppler interferometry measurements from fresh temporal bones. The final FE model was shown to be reasonable in predicting the ossicular mechanics of the human middle ear. Received: 18 February 2002 / Accepted: 6 June 2002 The preparation of temporal bone histological sections of Robert K. Dyer, Jr., MD is gratefully recognized. The Whitaker Foundation supported this work (Research Grant RG-98-0305).