Round window fistula

Round window fistula as a cause of sudden hearing loss was diagnosed in five people. It was associated with a sudden change in middle ear pressure in three, with heavy lifing in one, and was probably caused by a significant blast exposure in the other. The clinical features of the condition are varied, with hearing loss and tinnitus being the only constant findings in our patients. One case demonstrates, perhaps for the first time, the association of an abnormally mobile portion of the round window membrane with vertigo and nystagmus. Suggestions on identification and management of round window fistula are made.     

Characteristics of tinnitus induced by head injury

OBJECTIVE: To determine if the characteristics of tinnitus produced by head trauma are specific and exclusive when compared with other origins of tinnitus. DESIGN: Retrospective study using clinic test results and data from the Tinnitus Data Registry compiled from questionnaires, interviews, and testing. Tinnitus produced by head injury was compared with tinnitus of mixed origins, including no known origin. SETTING: A tinnitus referral clinic where all patients must see an otologist or an ear, nose, and throat physician prior to attending the clinic. PATIENTS: All patients had severe to moderately severe constant tinnitus and presented with tinnitus as the primary symptom. RESULTS: No exclusive characteristics were found to describe head injury-induced tinnitus. The tinnitus for the group with head injury was statistically significantly (P = .004) louder and occurred with greater incidence of continuing pain in the ears. The group with head injury also had more episodes of dizziness and a more severe form of tinnitus. However, no marked difference was noted in pitch of tinnitus, complexity (number of sounds) of tinnitus, or the minimum masking level. CONCLUSIONS: This retrospective study found that tinnitus induced by head injury was significantly (P = .004) louder than tinnitus induced from other causes but, interestingly, did not require higher levels of masking. The patients with head injury-induced tinnitus more frequently (P = .0003) displayed residual inhibition although the duration of residual inhibition was not different from that of the comparison group. Other symptoms associated with the tinnitus onset were more frequently mentioned by the group with head trauma-induced tinnitus, except for the condition of pressure sensation in the ears. Using a severity questionnaire, the group with head trauma-induced tinnitus rated their tinnitus as being more severe than did the comparison group. However, such things as pitch of the tinnitus, masking level, acceptance of wearable maskers, general hearing level, and complexity of the tinnitus did not distinguish the two groups.     

Tinnitus and Hearing Loss in Hamsters (Mesocricetus auratus) Exposed to Loud Sound.

Hamsters were trained to go left and right to sounds on their left and right sides, respectively. Silent trials were occasionally given in which no sound was presented. Hamsters exposed to a loud 2- or 10-kHz tone in 1 ear often shifted their responding on the silent trials to the side of the exposed ear, suggesting that they perceived a sound in that ear (i.e., tinnitus). The degree of tinnitus was related to the degree of the accompanying hearing loss (estimated by the auditory brainstem response). However, a conductive hearing loss (plugging 1 ear) did not cause a hamster to test positive for tinnitus. Tinnitus could be demonstrated within minutes following tone exposure, indicating an immediate onset, as occurs in humans. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reduced performance of male and female athletes at 580 m altitude

Patients with craniocervical mandibular (TMD) disorders can present with tinnitus as a primary or secondary complaint. The embryology and functional anatomy of the middle ear, temporomandibular joint, muscles of mastication and associated tendons, ligaments, blood vessels, nerves and lymphatics was found to be helpful in establishing etiologic concepts which relate tinnitus to these temporomandibular disorders. In addition to etiologic concepts, treatment modalities are described. The authors relate their experiences as well as those of others with different patient populations.     

Indications for middle ear obliteration within the scope of cochlear implant management

BACKGROUND: Cochlear implants have gained worldwide acceptance as a reliable method of rehabilitation of profoundly hearing-impaired patients. Due to thorough patient selection major postoperative complications rarely occur and are flap related in most cases. Deafness can develop during chronic suppurative otitis media, either coincidentally or secondary to the medical treatment; normally this condition is regarded as a contraindication for cochlear implantation. In cases with a mastoid cavity after surgical treatment for cholesteatoma, the electrode covered only by the epithelial lining will likely become exposed or extruded. Therefore we suggest the obliteration of the middle ear cleft with abdominal fat and the blindsac closure of the external ear canal before cochlear implantation in these conditions. PATIENTS: The average age of our 12 patients was 48 years, whereas the youngest was 2 1/2 years of age. Due to chronic inflammatory ear disease. 11 patients had a mastoid cavity on both ears. Eight patients had a cholesteatoma, the chronic bone destroying process in the temporal bone of two female patients was considered as a fibroinflammatory pseudotumor. The child had a congenital deafness in both ears with a Mondini dysplasia in CT scan. She had already developed two episodes of pneumococcal meningitis which was caused by a defect in the stapes footplate through which a liquor-filled cystic sac herniated in the middle ear. Because of a massive liquorrhoea after opening of the sac, we decided to obliterate the middle ear cleft after successful insertion of the electrode array. RESULTS: All active electrodes of 10 Nucleus implants (Cochlear) and two Clarion devices (Advanced Bionics Corp.) were successfully inserted in the cochlea of the 12 patients. After an average follow-up of 15 months, a temporary facial palsy in one patient and an insufficient closure of a retroauricular fistula over the mastoid cavity in two cases were observed as postoperative complications. One patient with a fibroinflammatory pseudotumor developed a massive inflammatory reaction in the implanted ear two months after cochlear implantation, which could not be controlled by conservative treatment. The implant had to be removed and local conditions settled after administration of immunosuppressive treatment with cyclophosphamide. The patient received a new implant seven months ago. CONCLUSIONS: Implantation of a foreign body in a potentially infected space which communicates intracranially means a surgical challenge which can be managed by obliteration of the middle ear after subtotal petrosectomy with abdominal wall fat combined with a reliable closure of the external ear canal. In case of massive inflammation we would prefer a two-stage procedure.     

Nasopharyngeal colonization with nontypeable Haemophilus influenzae in chinchillas

Colonization of the nasopharynx by a middle ear pathogen is the first step in the development of otitis media in humans. The establishment of an animal model of nasopharyngeal colonization would therefore be of great utility in assessing the potential protective ability of candidate vaccine antigens (especially adhesins) against otitis media. A chinchilla nasopharyngeal colonization model for nontypeable Haemophilus influenzae (NTHI) was developed with antibiotic-resistant strains. This model does not require coinfection with a virus. There was no significant difference in the efficiency of NTHI colonization between adult (1- to 2-year-old) and young (2- to 3-month-old) animals. However, the incidence of middle ear infection following nasopharyngeal colonization was significantly higher in young animals (83 to 89%) than in adult chinchillas (10 to 30%). Chinchillas that had recovered either from a previous middle ear infection caused by NTHI or from an infection by intranasal inoculation with NTHI were completely protected against nasopharyngeal colonization with a homologous strain and were found to be the best positive controls in protection studies. Systemic immunization of chinchillas with inactivated whole-cell preparations significantly protected animals not only against homologous NTHI colonization but also partially against heterologous NTHI infection. In all protected animals, significant serum anti-P6 and anti-HMW antibody responses were observed. The outer membrane P6 and high-molecular-weight (HMW) proteins appear to be promising candidate vaccine antigens to prevent nasopharyngeal colonization and middle ear infection caused by NTHI.     

A matching-to-sample feedback technique for training self-control of tinnitus.

Treated 30 individuals (aged 24–82 yrs) with subjective tinnitus aurium with a matching-to-sample feedback procedure. Ss' tinnitus sounds were reproduced audiometrically on all characteristics and were presented to them in the noninvolved ear or in both ears when the tinnitus was binaural. This experimental sound was then reduced in 5-db steps within sessions, and Ss had the task of concentrating on reducing the loudness of their tinnitus until a match was achieved between it and the experimental sound at each new db level. Results show a significant difference in db levels from baseline to final training session. Nearly all Ss demonstrated a marked reduction in tinnitus loudness, with several eliminating it completely. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Congenital cholesteatomas in the tympanic membrane

The etiology of congenital middle ear (ME) cholesteatomas is unclear. One etiologic possibility of ME cholesteatoma may be progression of a congenital tympanic membrane (TM) cholesteatoma. We recently have encountered three cases of congenital tympanic membrane cholesteatoma. Each child, ages 1, 3, and 14 years, presented with cholesteatoma of the tympanic membrane extending into the middle ear. These children have not had previous otologic surgery including myringotomy, nor had they had repeated middle ear infections, perforation, or trauma. Neither the 3-year-old nor 14-year-old child complained of hearing loss. Audiograms demonstrated only a mild conductive loss. Each child underwent excision with tympanoplasty. Although the middle ear component of the cholesteatoma was always more extensive than the pearl seen, the point of attachment was the TM and not the middle ear. This demonstrates one possible source for congenital cholesteatomas.     

Diimidazo[1,2-c:4'',5''-e]pyrimidines: adenosine agonist activity demonstrated by microphysiometry

Vertigo and dizziness are not common in childhood, but are probably present more often than was formerly thought. These symptoms caused mainly by o700is media and middle ear effusion, two of the most common diseases in children, have been neglected for a long time, both in the literature and in practice, until recently. The purpose of this study was to determine objectively the incidence of balance-related symptoms in children with long-lasting middle ear effusion and to discover whether these symptoms resolve after the insertion of ventilation tubes. One hundred thirty-six children, ages 4 to 9 years, were given electronystagmographic tests and the Bruininks-Oseretsky tests for motor proficiency before and after tube ventilation of the middle ear. The results were compared with those in 74 healthy children with no history of middle ear diseases. Pathologic findings were found in 58% of the children with chronic middle ear effusion, as compared with only 4% of the control group. The symptoms and signs of balance disturbances resolved in 96% of the children after ventilation tube insertion. The results of this study indicate that balance-related symptoms often encountered in young children may result from chronic middle ear effusion and that these symptoms will resolve after evacuation of the effusion and ventilation of the middle ear.     

Middle ear mucosa pathophysiology and healing processes in children with otitis media with effusion (OME)

Most otitis media with effusion (OME) in children heals spontaneously, but it is sometimes persistent and intractable. The major factors determining these different courses of OME are unknown. Identifying such factors would be clinically helpful. Factors affecting on the outcome of OME were studied experimentally and clinically. In animal experiment OME was induced in rabbit by occluding the Eustachian tube. Clinical study was conducted by investigating a histology of the middle ear mucosa, sampled from 64 children with OME (87 ears) who underwent middle ear tube ventilation. Furthermore, these cases studied how the degree of mastoid pneumatization before and after treatment, changes in the volume of the middle ear air cavity and the course after removal of the middle ear ventilation tube affected lesions in the middle ear mucosa. In animals, histology of the middle ear mucosa showed that in the early stages, the subepithelial layer of the middle ear mucosa was characterized by edematous hypertrophy and enlarged blood vessels. In later stages, it became fibrous as a result of chronic inflammation. These results suggest that lesions of the subepithelial layer are unlikely to recover. In clinical cases, histological changes in mucosal samples were rated on a two-point scale: changes in the epithelium and changes in the subepithelial layer. Re-pneumatization, a sign of healing of middle ear mucosal inflammation, was seen 12 months to 18 months after surgery. Among patients in whom the tube was left inserted for more than 18 months, only 11% had unfavorable outcomes and the recurrence rate was low. All patients who had recurrence of disease despite more than 18 months of tube insertion had prolonged inflammation in the middle ear mucosa. There results indicate that the air cavity returns to approximately normal degree of pneumatization more than 18 months after surgery, and that the extent of lesions in the middle ear mucosa, especially the subepithelial layer, is closely related to the healing of OME.     

Oropharyngeal tumors of dogs--a clinical study of 79 cases

Secretory otitis media is defined as a fluid in the middle ear without signs or symptoms of infection. As the aetiology and pathogenesis of the disease are unknown, and as it affects children aged from 3 to 12 years, treatment procedures proposed for management of secretory otitis media, are not uniform. Some authors [1, 4, 6] consider that functional or mechanical obstructions of the Eustachian tube could provoke secretory otitis. The purpose of the treatment is to remove exudate from the middle ear and appropriately ventilate it for a longer period. That could instantly normalize the hearing and exclude the appearance of late complications of secretory otitis. Although the disease could heal spontaneously, the treatment should be performed immediately for preventing sequelae of secretory otitis. The aim of the study was to evaluate possible aetiologic factors of secretory otitis in our population, and to evaluate results of lympanometry in children with exudate in the middle ear. There were 65 children, aged from 3 to 12 years (Table 1), who complained of deafness and were examined at the ORL Department in Banja Luka. The clinical examination revealed the integrity and color of tympanic membrane, scars, adhesions and atrophic areas. Audiometry and tympanometry had been performed in addition. Patients who proved to have exudate in the middle ear received nasal decongestants and mucolitics during three months, and were evaluated every three weeks by audiometry and tympanometry. Pathologic findings in the nose and epipharynx were the most common findings: enlarged adenoids in 38 (58%) patients, hypetrophic rhinitis in 15 (23%) and allergic rhinitis in 5 (8%) patients. Frequent relapses of middle ear infection in the first three years of life were found in 26 (40%) patients and early first attacks in the first year of life in 15 (23%) patients (Table 2). Premature onset (15%) and allergy (21%) had also been frequently found. Results of tympanometry and audiometry are shown in Table 3. Exudate in the middle ear and type B tympanogram were found in 86 ears, while in other patients dysfunction of the Eustachian tube and type C1 and C2 tympanograms were found. After 6 weeks the exudate disappeared in 16 ears and tympanogram converted in type A and type C2, while the initially found C1 tympanogram was transformed in type A in 5 of 13 ears. After 12 weeks the tympanogram type B was found in 46 ears, while in 40 ears (47%) the tympanogram was changed in type A and type C2. After 6 and 12 weeks of therapy tympanometric types were statistically examined by chi 2 test. We have found a significant difference in tympanometric types and prevalence of type A and C1 tympanograms. Paracentesis and insertion of ventilating tubes were done in 46 ears with the remaining exudate. We have found mucous exudate in 35 (76%) ears associated with retraction and scars of tympanic membrane (Table 4), what indicated that the longer duration of mucous exudate caused degenerative changes in the middle ear. Serous exudate, found in 9 ears (24%), did not affect the color and integrity of the tympanic membrane. Sensitivity of tympanometry in detection of exudate in the middle ear was 96%. Secretory otitis media is a frequent disease in childhood, that could cause functional and morphological sequelae in the middle ear. As for now, there is no unique concept of diagnosis and treatment of the disease, and it is still a current problem. We suggest a three-month evaluation of tympanometric and audiometric patterns, repeated every three weeks, in children suspected of having exudate in the middle ear. There is a large trend of spontaneous disappearance of exudate in the middle ear and changing of tympanogram type. Such children should be evaluated over the period of one year, and if there is no relapse additional treatment should not be carried out. If exudate in the middle ear persists for three months and type of the tympanogram is unchanged, myringotomy and insert     

Biofeedback-based behavioral treatment for chronic tinnitus: Results of a randomized controlled trial.

Many tinnitus sufferers believe that their tinnitus has an organic basis and thus seek medical rather than psychological treatments. Tinnitus has been found to be associated with negative appraisal, dysfunctional attention shift, and heightened psychophysiological arousal, so cognitive-behavioral interventions and biofeedback are commonly suggested as treatments. This study developed and investigated the efficacy of a biofeedback-based cognitive-behavioral treatment for tinnitus. In total, 130 tinnitus patients were randomly assigned to an intervention or a wait-list control group. Treatment consisted of 12 sessions of a biofeedback-based behavioral intervention over a 3-month period. Patients in the wait-list group participated in the treatment after the intervention group had completed the treatment. Results showed clear improvements regarding tinnitus annoyance, diary ratings of loudness, and feelings of controllability. Furthermore, changes in coping cognitions as well as changes in depressive symptoms were found. Improvements were maintained over a 6-month follow-up period in which medium-to-large effect sizes were observed. The treatment developed and investigated in this study is well accepted and leads to clear and stable improvements. Through demonstration of psychophysiological interrelationships, the treatment enables patients to change their somatic illness perceptions to a more psychosomatic point of view. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Overexpression of Glut1 and Glut3 in stage I nonsmall cell lung carcinoma is associated with poor survival

We report the electrophysiologic findings of myoclonus in a patient with Huntington's disease (HD). This patient was studied postoperatively after a bilateral fetal cell transplant in his striatum. Incomplete transient improvement was seen in the myoclonus, followed by gradual deterioration. The myoclonus itself had a cortical correlate and was associated with an enlarged somatosensory evoked potential (SEP), consistent with the presence of cortical reflex myoclonus. An enlarged SEP has not been previously reported in myoclonus associated with HD. The postulated mechanisms for myoclonus, when it occurs in HD, have differed in the literature. The reason for the transient improvement of the myoclonus following transplantation is unclear, but this case raises the possibility that basal ganglia circuits may modulate cortical myoclonic activity.     

Features of aspergillosis in ENT. Clinical features of aspergillosis in ENT (author's transl)

Etiology, pathogenesis and clinical features of fungal diseases in ENT caused by Aspergillus are discussed. In this paper special stress is put upon the diagnosis and therapy of the Aspergillosis of the paranasal sinuses and the ear. Out of a group of 65 patients with Aspergillosis of the nose and paranasal sinuses 25 were examined in detail. Two of them suffered from a malignancy, while the remainder of the group had been in general good health. It was remarkable, that many patients got into touch with domestic animals, garden mould and soil of ornamental plants. In X-ray 12 calcareous concrements were detected. In one case only histological signs of an invasion of Aspergillus could be demonstrated. Fungus infections of cavity of radical mastoidectomy and external ear were often seen and easily diagnosed because of their clinical appearance. In the last years we have neither observed Aspergillosis of the middle and inner ear, nor of the larynx.     

Objective tinnitus and velar myoclonus: apropos of a case of a child

The syndrome in which velar myoclonus is associated with objective tinnitus is rare, and in the adult corresponds most commonly with a lesion in the dentato-rubro-olivary tract. In the child, no lesion can usually be found. The disorders of function resulting from this syndrome are very disabling. Many forms of treatment have been proposed, and the results have been found to be disappointing. The authors report the case of a child in which muscle relaxants were used to very good effect, and emphasize the fact that the natural history of the condition in childhood is one of spontaneous remission, so that aggressive treatment is not appropriate.     

Evaluation of cefaclor in acute otitis media caused by ampicillin-resistant H. influenzae

Cefaclor was used to treat 13 children with acute otitis media caused by ampicillin-resistant strains of Hemophilus influenzae. The children were re-examined on days 4, 10, and 28. Pharmacologic compliance was assessed by means of a bioinhibition assay on a urine specimen obtained on days 4, 7, and 10. Nine of the 13 children had evidence by tympanogram of residual otitis media with effusion (secretory otitis media). Of these, three were noted to have a bulging, yellow or grey eardrum, which suggested an ongoing acute process. A second middle ear culture was obtained from two of the 3 children, but no pathogens were recovered. Two others had recurrence of otitis shortly after cessation of therapy. Cefaclor is an acceptable antibiotic for the treatment of ampicillin-resistant acute otitis media; but, after cefaclor therapy, some children continued to have a bulging eardrum and sterile pus in the middle ear or had recurrences of otitis soon after cessation of therapy.     

Wegener''s granulomatosis presenting as a recurrence of chronic otitis media

INTRODUCTION: Tinnitus is still one of the most frequent symptoms encountered by the otorhinolaryngologist. Diagnosis and therapy present high demands due to the complex etiology and secondary symptoms. PATHOPHYSIOLOGY: In contrast to objective ear ringing with a physical sound source near the ear, tinnitus is faulty coding within the auditory system. Damage due to all kinds of causes can lead to a change of spontaneous activity in the auditory system. The result is a subjective auditory impression which is increased by further learning processes. DIAGNOSTICS: The aim of otorhinolaryngologic and especially audiologic diagnostic studies is to find the cause of the tinnitus. Modern methods for the objectivation of tinnitus are still experimental. The psychosomatic diagnostic studies evaluate secondary symptoms. THERAPY: Acute tinnitus is treated like sudden deafness. For chronic forms, the analysis of the causes is particularly important for developing an individual consultation and therapy plan. Providing information of the patient is the first step for a sensible treatment of the symptoms. The retraining therapy represents a learning process to reduce subjective symptoms, inconvenience, and loudness. Supportive therapy includes the use of instrumentation and medication. CONCLUSION: Acute tinnitus is often curable. However, only palliative treatment is available for chronic tinnitus. The otorhinolaryngologist plays a crucial role in the management of the disorder.     

Therapeutic approach in blast injuries of the ear

Otic blast injury is caused by arrhythmic air blast wave. The perforation of the tympanic membrane is the commonet finding associated with lacerations of mucosa in the middle ear. Makki [6] published 34 cases of myringoplasty after war blast injuries. However, healing of such perforations is common; Kerr [7] noted a healing rate of 83% after the blast injury. The aim of the study was to evaluate different therapic procedures of otic blast injuries. There were 74 patients with bilateral otic blast injuries, who underwent otomycroscopic examination. The following parameters were noted: Integrity of tympanic membrane and size of perforation, presence of haemorrhagic exudate in the middle ear and median value of conductive deafness (Table 2). Main symptoms, presented in Table 1 were: pain, deafness and otohaematorrhoea. The first group of 19 patients received antibiotics by parenteral way during 7 days according to the bacterial finding in ear exudate. Healing rate was dependent on the size of tympanic membrane perforation, and rated from 71% in perforation of one third of tympanic membrane to 25% in total perforation of tympanic membrane. Data are presented in Table 3. The second group of 24 patients received the same therapy as the first treatment, plus otomycroscopic removal of haemorrhagic exudate, lacerated middle ear mucosa, and repair of tympanic membrane lacerations. Healing rate was significantly better than the one obtained in the first group (Table 4). Persistent tympanic perforation, as indicator of failed therapy, was present in 5 (35%) of all examined ears with two thirds of tympanic membrane perforation in the first group, while in the second group the rate was 3 (12%). The third group received the same therapy as the second treatment, including administration of amicacyn into the external auditory canal. The results were statistically compared by chi 2 test, and we found that the second therapy protocol was significantly better. There was no significant difference between the second and the third therapy protocols. We found blast ruptures of tympanic membrane and auditory ossicles chain discontinuity in 88% of examined ears. In our material the high incidence of total tympanic membrane ruptures and subtotal ruptures (48%) is quite different in comparison to other authors [5-7]. We consider it as the effect of high power blast wave. Loss of conductive hearing was present in 91% of blast injured patients, while 7.4% of patients had mixed, predominantly senzoneural deafness. Consequently, in addition to mechanic blast injuries acoustic trauma could profoundly damage the inner ear. Spontaneous healing of tympanic membrane occurred in 71% of injured persons and this was a better result than the results obtained by other authors [3, 4, 6]. The spontaneous healing of tympanic membrane failed if infection of the middle ear occurred or blast caused the total tympanic membrane perforation. In the second and third therapy protocols significantly higher healing of tympanic membrane ruptures was evident; it rated from 88% to 91%. Better results could be explained by the effect of optimal healing conditions, based on removal of exudate from the middle ear and necrotic parts of tympanic membrane, completed by fitting of lacerated parts of tympanic membrane and antibiotic prophylaxis. Healing of tympanic membrane without scars and adhesions was more frequent than in patients treated only with antibiotics. Incidence of undesired outcome of persistent perforation of tympanic membrane was reduced. To prevent posttraumatic complications in the middle ear, we recommend early cleaning of margins, reposition of lacerated fragments of tympanic membrane, and removal of haemorrhagic exudate. Myringoplasty should be performed if spontaneous healing of tympanic membrane did not occur after 6 months. CONCLUSION: Otic blast injury was frequently found in war induced trauma. (ABSTRACT TRUNCATED)     

Treatment of Menière's disease with betahistine (author's transl)

Betahistine was gien to 86 patients with Meniere's disease in a thric daily dose of 8 mg. All patients except for three had earlier been treated medically without success. Symptomatic improvement occurred overall in 82,5%, including in 66% ear pressure symptoms, in 59.5% headache in 57% tinnitus, and in 35% hearing, although this latter statistically was not confirmed. The duration of administration of betahistine is therapeutically important and benefit from 4 months' continued use was demonstrated. After stopping treatment, the therapeutic effects were maintained and more than 6 months later improvement in hearing and ear pressure symptoms was still recorded. There was though a deterioration in symptoms of vertigo, tinnitus and headache in 18% over the same period. The shorter the duration of the symptoms the better the therapeutic effect gained. Improvement estimations of 81% in patients affected for up to 1 month, of 65% in patients affected from 1 to 12 months, and of 50% in patients affected more than one year were obtained. These results compare averagedly with the widely varible results of others. The management of Meniere's disease with betahistine can be regarded as an improvement in the conservative therapy of this disorder.     

Alterations in gastric physiology in Helicobacter pylori infection: causes of different diseases or all epiphenomena?

Although mice of the C3H strain normally respond to bacterial lipopolysaccharide with appropriate immune system activation, mice of the C3H/HeJ substrain do not because of a gene defect. This suggests they may be more susceptible to opportunistic bacterial infections and more likely to have otitis media than a normally responding substrain, such as the C3H/HeSnJ. Therefore these two substrains were evaluated for incidence of spontaneous middle ear disease at 2, 4, 6, 10, 12, 15, and 18 months of age. Auditory brain stem response audiometry to pure tones of 4, 8, 16, 24, and 32 kHz was performed to establish the impact of middle ear disease on auditory function. None of the lipopolysaccharide-responsive C3H/HeSnJ mice demonstrated middle ear disease. However, middle ear disease was present in 33% of the C3H/HeJ mice. The conductive loss caused by the otitis media resulted in auditory brain stem response threshold shifts of 15 to 40 dB SPL, lowered peak amplitudes, and increased latencies. Reduced lipopolysaccharide responsiveness by C3H/HeJ mice makes them less capable of reacting immunologically to bacterial infection and presumably underlies the failure to clear middle ear disease. The C3H/HeJ mouse may provide a valuable model in which to study lipopolysaccharide biologic activity and related middle ear inflammatory or immune mechanisms.