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At least 181 records · Page 10Linked to original sources
PubMed1976

Experimental viral infections of the inner ear. I. Acute infections of the newborn hamster labyrinth.

Acute viral infections of the inner ear were produced in neonatal hamsters. Viruses were inoculated percutaneously through the temporal cartilage into the endolymphatic and perilymphatic spaces of the labyrinth or were inoculated intracerebrally to reach the perilymphatic spaces via the cochlear aqueduct. Selective vulnerability of inner ear structures was demonstrated using a variety of viruses. Influenza virus infected only the mesenchymal cells of the perilymphatic channels of the cochlea; mumps virus infected principally endolymphatic structures; herpes simplex virus infected primarily the sensory cells of the labyrinth; and rubeola and vaccinia viruses infected both perilymphatic and endolymphatic cells.

Acute Disease↗
PubMed1984

[Nasal infection of the domestic cat with feline herpesvirus as an animal model of experimental viral labyrinthitis].

Looking for a suitable animal model of experimental labyrinthitis we performed in vivo infections of the domestic cat with feline rhinotracheitis virus. After instillation of the virus suspension into the nose of the anaesthetized cat we could find the complete virus particles in so-called virus factories in the nasal mucosa four days later by means of electron-microscopy. The adjacent ganglia of the olfactory nerve were stained by immunohistochemical methods and showed positive viral antigen. After embedding of the cochlea for electron microscopy virus particles could be demonstrated in the inflammatory cell material in the scala tympani. Our experimental model seems to be suitable for further studies of the rhinogenic way of infection in experimental viral labyrinthitis.

Animals↗
PubMed1994

Particulate matter within the membranous labyrinth: pathologic or normal?

Recent reports have suggested that particulate matter identified within the membranous portion of the posterior semicircular canal is responsible for the development of positional vertigo. To further investigate this claim, a posterior canal fenestration was carried out in ten patients undergoing acoustic tumor removal via a translabyrinthine approach. Particles were identified in the membranous labyrinth in nine patients. One of these patients described positional vertigo preoperatively. Electron microscopy demonstrated particles within the membranous labyrinth that appeared to be of mixed proteinaceous and mineral content. These data suggest that further studies must be undertaken before the theory of endolymphatic particle migration can be confirmed as the etiology of positional vertigo.

Adolescent↗
PubMed2001

Virtual endoscopy of the labyrinth, using a 3D-FastASE sequence.

Virtual endoscopy (VE) of the labyrinth was performed using three-dimensional (3D)-fast asymmetric spin-echo MR imaging. The spatial resolution requirements and the usefulness of zero-fill interpolation (ZIP) were evaluated, and VE was used to examine three patients. The (0.6-mm) voxel data with ZIP satisfies the minimum requirements for VE for evaluation of the complex 3D anatomy and pathology of the labyrinth. J. Magn. Reson. Imaging 2001;13:792-796.

Adolescent↗
PubMed1994

Detection of cochlear dysfunction by the measurement of transiently evoked otoacoustic emissions in guinea pigs with autoimmune-induced labyrinthitis.

For the evaluation of functional inner ear lesions caused by an autoimmune-induced labyrinthitis, transiently evoked otoacoustic emissions (TEOAEs) were detected in guinea pigs before and after transfer of sensitized lymphocytes from animals suffering from a labyrinthitis induced by the foreign protein keyhole limpet hemocyanin (KLH). Initially TEOAEs were detectable from 47 of 62 ears (76%) in healthy guinea pigs. These animals then were used as recipients for sensitized lymphocytes from donors exclusively. Three months after cell transfer the incidence of TEOAEs was reduced to 48% in animals receiving lymphocytes from donors sensitized with KLH intradermally and intracochlearly. In recipients of lymphocytes from donors sensitized only intradermally and in untreated animals no significant alteration of the TEOAE incidence was found. These findings showed strong correlation with those from scanning electron microscopy of the organ of Corti, indicating that the measurement of TEOAE is a useful, time-saving tool for the detection of cochlear dysfunction caused by sensitized lymphocytes in experimental animal. The present findings also show that the migration of sensitized lymphocytes actually leads to functional lesions in the cochlea.

Animals↗
PubMed2004

Electrical stimulation of labyrinths and vestibular reactions.

Stimulation of the labyrinth in rabbits and guinea pigs with ascending (cathode) or descending direct current (anode) induced deviation and nystagmus of the eyes, head turn and tilt, and other reactions. Anodization of both labyrinths was followed by the disappearance of reflexes, suppression of vestibular reactions to adequate stimulation, and loss of swimming ability. The state of animals returned to normal after breaking the electric circuit.

Animals↗
PubMedDate not supplied

Human cytomegalovirus labyrinthitis.

The purpose of this report is to present a review of the clinical and histopathologic findings in human cytomegalovirus (HCMV) labyrinthitis. Human cytomegalovirus infection was first recognized in its congenital disseminated form and, subsequently, in a subclinical form. In 1968, the first temporal bone demonstration of endolabyrinthine infection was reported. To date, there have been reports made on only nine temporal bones in infants with HCMV infection. The light microscopic findings, in general, have been similar, with cytomegalovirus inclusion-bearing cells involving the nonneuroepithelial cells in both the cochlear and vestibular endolabyrinth. A few cases have been studied with fluorescent antibody methods, but have resulted in conflicting reports regarding the presence of virus in cells of the organ of Corti and spiral ganglia. Subclinical congenital HCMV infection, including labyrinthine infection, has also been studied. Only two groups have performed major prospective studies along with systematic and careful periodic audiologic evaluation in cytomegalovirus congenitally infected children. Their findings demonstrated significant hearing loss in 33% to 48% of symptomatic patients and in 6.9% to 13% of asymptomatic children. There also was evidence of progressive hearing loss in some of these children. Vestibular dysfunction is less well characterized. The long-term sequelae may include Meniere's syndrome. Acquired HCMV infection in children and adults has not been demonstrated histopathologically, although it has been associated with sudden deafness and acute labyrinthitis. This observation is based primarily on serologic data.

Cytomegalovirus↗
PubMed1995

Value of Gd-DTPA-enhanced MR imaging of the labyrinth in patients with sudden hearing loss.

Recent reports describe labyrinthine enhancement on MRI as a highly specific sign of labyrinthine disease. This paper reports 44 patients with unilateral sensorineural hearing loss (SNHL) and laboratory evidence of cochlear damage investigated with Gd-enhanced MR imaging. Enhancement of the cochlea was observed in only one patient with a lesion at the fundus of the internal auditory canal (IAC) that extended into the cochlea after Gd-DTPA administration. In one more patient, MR imaging demonstrated large vestibular aqueducts as underlying cause for his hearing loss, but no enhancement of the labyrinth was observed. No abnormal signal intensity on precontrast MR scans nor pathologic enhancement of the membranous labyrinth were identified in the other 42 patients. Gd-enhanced MR imaging appears to be insensitive in demonstrating labyrinthine disease and normal examination findings in a patient with sudden SNHL cannot exclude damage at the cochlear level.

Adolescent↗
PubMed1996

[Pneumococcal meningitis revealing dysplasia of the bony labyrinth in an infant].

BACKGROUND: Dysplasias of the bony labyrinth are frequently associated with cerebrospinal fluid fistula and are usually discovered because of recurrent meningitis. CASE REPORT: A 1 year-old infant was admitted for a pneumococcal meningitis which appeared 2 days after the occurrence of a clear otorrhea from the right ear. The same organism was isolated from the otorrhea fluid, which also contained cerebrospinal fluid as confirmed cytochemically. The meningitis rapidly resolved with antibiotic treatment. Auditory brain stem responses were abolished from the right ear. CT of the temporal bones showed a pseudo-Mondini type labyrinth dysplasia at the right ear and Mondini type dysplasia at the left one. A translabyrinthine cerebrospinal fluid fistula was discovered by surgical exploration of the right ear, occurring through a perforation in the stapedial foot plate. The leak was cured by packing the vestibule and obturating both oval and round windows. Three years after the operation, the child did not experience any further episode of otorrhea or meningitis. CONCLUSIONS: Features suggesting a translabyrinthine fistula, especially otorrhea and deafness, should be systematically searched in any child with bacterial meningitis. Closure of these fistulas can prevent severe infectious recurrences.

Cerebrospinal Fluid Otorrhea↗
PubMed2006

Pathogenesis of cytomegalovirus-associated labyrinthitis in a guinea pig model.

Cytomegalovirus infects fetuses through the placenta, resulting in various congenital disorders in newborns, including hearing loss. We developed a monoclonal antibody to guinea pig cytomegalovirus (GPCMV) that was available for immunohistochemistry, and investigated the expression of the GPCMV antigen in animal models of direct and congenital infections. Injection of GPCMV, directly to the inner ear, increased the sound pressure level and resulted in labyrinthitis with severe inflammation. Immunohistochemistry detected GPCMV-infected cells mainly in the scala tympani, scala vestibule and spinal ganglion, but rarely in the cochlear duct. Injection of GPCMV to 5-week pregnant guinea pigs resulted in severe labyrinthitis in fetuses. Immunohistochemistry detected GPCMV-infected cells in the perilymph area and spinal ganglion, but not in the endolymph area, including hair cells. These data suggest that the virus spreads via the perilymph and neural routes in the inner ear of both models of direct and congenital infections.

Animals↗
PubMed1995

Management of the open labyrinth.

Labyrinthine fistulas occur in approximately 5% of cholesteatoma cases, but the management of this difficult problem remains controversial. This study assessed the preoperative presentation and outcome in 37 patients operated on for cholestatoma complicated by labyrinthine fistula. Therapy involved removing the matrix from each fistula and reconstructing the bony wall of the labyrinth with bone dust, fibrin glue, and perichondrium. Corticosteroids were added to the management protocol in more recent cases. A fistula classification scheme was introduced to standardize the reporting of the extent of labyrinthine involvement and results of treatment. The most common preoperative symptoms, sensorineural hearing loss and vertigo, were notably lacking in more than 30% of patients. The fistula test was positive in only 32% of cases. Corticosteroids were seen to have a beneficial impact on postoperative outcome in those cases involving injury to the membranous labyrinth or removal of perilymph.

Bone Transplantation↗
PubMed2001

Expression of p-glycoprotein is associated with that of multidrug resistance protein 1 (MRP1) in the vestibular labyrinth and endolymphatic sac of the guinea pig.

Expression of p-glycoprotein (p-gp) and multidrug resistance protein 1 (MRP1) was detected in the vestibular labyrinth and endolymphatic sac (ES) of the guinea pig by immunohistochemical staining using anti-p-gp monoclonal antibody (mAb) C219 and anti-MRP mAb MRPr1. P-gp was detected in capillary endothelial cells of the crista ampullaris, utricle, saccule and ES. MRP1 was detected in the epithelial lining of the crista ampullaris, utricle, saccule, and epithelial cells of the ES. Since p-gp and MRP1 act as extrusion pumps, they may coordinate with each other in vestibular organs and ES and play an important role in the blood-labyrinth barrier.

ATP Binding Cassette Transporter, Subfamily B↗
PubMed1986

Transfer function of right- and leftward eye movements in patients with unilateral labyrinth.

In patients with loss of unilateral labyrinthine function, the dynamic characteristics of rightward eye movement and leftward eye movement induced by the healthy labyrinth were displayed respectively. In patients who were examined within a few months after loss of unilateral labyrinthine function, the gain of eye movement toward the healthy labyrinth was low compared with that of eye movement toward the opposite direction. These differences in the gain were remarkable in the frequency range from 0.01 to 0.1 Hz. But those differences in the gain were not detected in patients who were examined more than 3 months after loss of unilateral labyrinthine function.

Adult↗
PubMed2002

Prominent expression of Narp in central vestibular pathways: selective effect of labyrinth ablation.

Recent in vitro studies demonstrated that Narp, a secreted immediate early gene (IEG) product, induces AMPA receptor clustering. Accordingly, Narp has been implicated in mediating activity-dependent changes in synaptic efficacy. To help define the role of Narp in vivo, we conducted immunohistochemical studies of Narp in rat brain. Unexpectedly, we found robust Narp expression in several discrete areas linked to the vestibular system: the anterodorsal nucleus (ADN) of the thalamus, which relays head orientation information to the cortex, the lateral vestibulospinal (Deiters') nucleus and Purkinje cells in the flocculonodular lobe of the cerebellum. Although strong Narp expression in Deiters' nucleus and the cerebellum was present consistently, Narp expression in the ADN displayed a high degree of variability among animals. To check if this variability in ADN Narp expression reflects its dependence on fluctuating levels of vestibular input, we monitored Narp immunostaining following bilateral labyrinth ablation. This procedure significantly suppressed Narp immunostaining in the ADN, indicating that it is stimulated by naturally occurring vestibular input. In contrast, labyrinth ablation did not affect Narp staining in Deiters' nucleus or the flocculonodular lobe of the cerebellum, presumably because these areas are driven by inputs from multiple systems. As previous studies implicate Narp in synaptic plasticity, these findings suggest that this IEG may mediate ongoing adjustments in synaptic strength or connectivity in several pathways linked to the vestibular system.

Animals↗
PubMed1995

[Possibilities for preserving hearing in labyrinth fistulas of different degrees of severity].

The labyrinthine fistula continues to be one of the most common complications in ears with cholesteatoma. Fifty-one patients with labyrinthine fistula were identified in a series of 1243 cases with cholesteatoma operated upon between 1989 and 1993 at the University ENT Clinic Wuerzburg. The surgical management concept comprised of removing the cholesteatoma matrix, categorizing the fistula type, and immediate covering of the labyrinthine capsule defect with bone dust, perichondrium and fibrin glue. The classification system of the fistulae used in the study used the depth of labyrinthine involvement as a criterion and also took into account the possibility of intentional or accidental damage to the labyrinth during surgical manipulation (Fig. 1). From 1991 on, patients were treated with 500 mg of Presnisolon 21 hydrogen succinate in a single intravenous dose, at the time the fistula was corrected. The postoperative hearing results were graded based on the extend of preservation of inner ear function at or near the preoperative level. None of the patients who had corticosteroid therapy suffered a profound sensory neural hearing loss (Fig. 2, 3), whereas five ears without steroids and a deep fistula lost function completely. The study concluded that corticosteroids have a beneficial impact on postoperative outcome in cases with severe injury to the membranous labyrinth.

Adult↗
PubMed2003

Model experiment of benign paroxysmal positional vertigo mechanism using the whole membranous labyrinth.

Whole membranous labyrinths of bullfrogs were used in order to replicate the human vestibule. The posterior semicircular canals (PSCs) were exposed, leaving the remaining membranous labyrinth encapsulated in the otic capsule. Vibration was applied to the surface of the bony capsule using a conventional surgical drill in order to dislodge the otoconia from the utricle. The position of the preparation was controlled so that the dislodged otoconia were attached to the cupular surface. This was regarded as a cupulolithiasis model. The action potentials changed instantaneously according to the gravitational force on the cupula. When the otoconia were dislodged and held within the PSC lumen, the position of the whole preparation was changed so that the otoconia moved back and forth within the canal lumen. This is a model of canalolithiasis. The action potentials changed in combination with the otoconial movement after a latent period. Both cupulolithiasis and canalolithasis are potentially valid mechanisms of benign paroxysmal positional vertigo (BPPV). However, canalolithiasis is the most likely mechanism of BPPV, which is usually characterized by nystagmus of short duration and long latency. A vibratory stimulus was able to detach the otoconia from the utricle, suggesting that mechanical insult could be a possible etiology of BPPV.

Animals↗
PubMed2000

Magnetic resonance imaging for evaluation of otic labyrinth pathology.

The auditory (cochlear) labyrinth, the cochlea, holds the hearing sensory receptors. The vestibular labyrinth contains the sensory receptors for balance, which lie in the three semicircular canals and in the otolithic organs (the saccule and utricle). Pure tone audiometry and brain stem evoked audiometry can help to differentiate a peripheral cochlear disorder from central lesion. The type of nystagmus, severity of postural instability, and neurological evaluation can help to differentiate a peripheral vestibular disorder from a central vestibular lesion. The decision whether to perform an appropriate imaging such as brain imaging versus labyrinthine imaging depends on the clinical and paraclinical information provided to the radiologist by the neurotologist, neurologist, or other clinicians. The magnetic resonance imaging characteristics of peripheral cochlear and vestibular lesions are the main focus of this article.

Cochlear Diseases↗