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1/32. Study of systemic lupus erythematosus in temporal bones.

    Despite some reports of sensorineural hearing loss with systemic lupus erythematosus (SLE), its pathologic correlate has remained unidentified due to the scarcity of human temporal bone studies. We here present findings in 14 temporal bones from 7 patients with SLE, examined histologically and immunohistochemically for pathologic conditions in the cochlea that might relate to their otologic histories. Blue-staining concretions were seen in the stria vascularis of 6 ears. Most of the cases showed a loss of spiral ganglion cells, with various degrees of hair cell loss and atrophy of the stria vascularis. One ear demonstrated formation of fibrous tissue and bone throughout the cochlea, with complete loss of the membranous labyrinth. Cochlear hydrops was found in only 1 ear. These findings in temporal bones from patients with SLE are discussed in relation to autoimmune disease of the inner ear.
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2/32. Histopathologic features of the temporal bone in usher syndrome type I.

    Temporal bones of 2 patients with Usher syndrome type I were examined using light microscopy. In both patients, findings from histopathologic examination of the cochlea were characterized by degeneration of the organ of corti, which was most marked in the basal turn, atrophy of the stria vascularis, and a decrease in the number of spiral ganglion cells. The cochlear nerve appeared to be diminished. The sensory epithelium of the saccular and utricular maculae of patient 1 was normal for age. The left temporal bone of patient 2, classified as Usher syndrome genetic subtype USH1D or USH1F, demonstrated the typical signs of severe cochleosaccular degeneration. Present cases and cases from the literature were reviewed in search of an explanation for the above-described differences in histologic findings.
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3/32. Cerebro-oculo-facio-skeletal syndrome as a human example for accelerated cochlear nerve degeneration.

    BACKGROUND: Cerebro-oculo-facio-skeletal (COFS) syndrome is a rare autosomal-recessive disorder that includes microcephaly, severe mental retardation, and multiple congenital anomalies. Otologic findings are usually limited to descriptions of the auricles. PATIENT AND methods: The authors report inner ear histopathologic findings of a deceased 13-year-old patient with COFS. A histologic study of the inner ear in COFS syndrome has not yet been described. This patient was documented as having a profound bilateral sensorineural hearing loss at the age of 2 years. RESULTS: Histologic evaluation revealed accelerated neural and neuronal degeneration at the cochlear and retrocochlear levels. Remaining myelinated nerve fibers, counted in the spiral lamina, had degenerated by up to 97% when compared with normal innervation densities. Afferent nerve fibers innervating inner hair cells were completely absent, whereas medial efferent fibers to outer hair cells were found. vestibular nerve fibers were less affected. CONCLUSION: The authors report inner ear findings that differ from animal models of primary cochlear neural degeneration and that resemble the pattern of hereditary cochlear nerve degeneration reported in Friedreich's ataxia.
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4/32. temporal bone histopathologic and genetic studies in Mohr-Tranebjaerg syndrome (DFN-1).

    OBJECTIVE: To describe the temporal bone histopathologic and genetic abnormalities in a case of Mohr-Tranebjaerg syndrome. BACKGROUND: Mohr-Tranebjaezrg syndrome (DFN-1) is an X-linked, recessive, syndromic hearing loss, characterized by postlingual sensorineural hearing loss with onset in childhood, followed in adult life by progressive dystonia, spasticity, dysphagia, and optic atrophy. The syndrome is caused by mutations in the DDP (deafness/dystonia peptide) gene, which are thought to result in mitochondrial dysfunction with subsequent neurodegeneration. The temporal bone pathologic changes in this syndrome have not been reported. methods: hearing loss developed in the patient at age 4, blindness at age 48, and dystonia at age 57. Genetic studies on peripheral blood showed a l51delT mutation in his DDP gene. He died at age 66. The right temporal bone was subjected to light microscopy and polymerase chain reaction-based analysis of the DDP gene sequence. RESULTS: There was near complete loss of spiral ganglion cells with loss of nearly all peripheral and central processes. Only 1,765 spiral ganglion cells remained (8.5% of mean normal for age). The organ of corti (including hair cells), stria vascularis, and spiral ligament were preserved. There was also a severe loss of Scarpa's ganglion cells with preservation of vestibular hair cells. The population of geniculate and trigeminal ganglion cells appeared normal. sequence analysis from temporal bone dna showed the 15ldelT DDP gene mutation. CONCLUSION: Sensorineural hearing loss in Mohr-Tranebjaerg syndrome is the result of a postnatal, progressive, severe auditory neuropathy.
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5/32. Otopathology in a case of type I Waardenburg's syndrome.

    We report a case of type I Waardenburg's syndrome that provides insight into the etiopathogenesis of sensorineural hearing loss (SNHL) in this syndrome. The subject, a 76-year-old woman with type I Waardenburg's syndrome (dystopia canthorum, heterochromia irides, and white hair), had congenital low-frequency SNHL in her right ear only, which had remained relatively stable throughout her life. blood leukocyte dna studies revealed a PAX-3 mutation with a 1 base pair C-to-A substitution in exon 5 at base 602. light microscopic studies of the right cochlea showed intact neurosensory structures in only the lower basal turn, with the remainder of the cochlea showing absence of melanocytes, absence of stria vascularis, missing hair cells, dysmorphogenesis of the tectorial membrane, and lack of peripheral processes of the spiral ganglion cells. There was pathological alteration of the vestibular dark cells with marked reduction of melanocytes associated with these dark cells. The left inner ear was normal, with a full complement of neurosensory structures, including melanocytes. Because the PAX-3 gene is involved in neural crest development and melanocytes migrate from the neural crest to the ear, the findings in this case are consistent with the hypothesis that defective melanocyte migration or defective melanocyte function results in defective development of the stria vascularis (and perhaps other structures of the ear), leading to SNHL.
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6/32. Preserved otoacoustic emission in a child with a profound unilateral sensorineural hearing loss.

    We report a case of profound unilateral sensorineural hearing loss with good response of otoacoustic emission. The patient was a 5-year-old boy. who was diagnosed to have unilateral hearing impairment on pure tone audiometry at the first visit. The affected ear showed the absence of auditory brainstem response; however, its transiently evoked otoacoutic emission and distortion product otoacoustic emission were considered to be normal. These findings indicated that the outer hair cell of cochlea was not impaired and that the impairment should be localized between inner hair cells, primary afferent fiber or its synapses, spiral ganglion of the cochlea and acoustic fiber, or at a combination of these areas. That is, evaluation of otoacoustic emission was useful in determining the region of impairment in sensorineural hearing loss. Further follow-up will be necessary to differentiate the present case from auditory neuropathy.
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7/32. Aminoglycoside ototoxicity: a human temporal bone study.

    OBJECTIVE: hearing loss after aminoglycoside administration has been thought to result primarily from hair cell injury. The purpose of the study was to determine the potential for direct injury of spiral ganglion cells and hair cells in cases of documented human aminoglycoside ototoxicity. STUDY DESIGN: Retrospective case review. methods: The clinical course of two individuals with aminoglycoside ototoxicity are documented, including the details of administration of tobramycin and other ototoxic medication and serial audiograms. The temporal bones were processed, and the cochlear elements quantified. RESULTS: Histopathological study of the temporal bones from the individuals in the study demonstrated reduction of both ganglion cell and hair cell populations. spiral ganglion cell loss was not necessarily subadjacent to areas of hair cell loss in cases of aminoglycoside ototoxicity. Instead, spiral ganglion cell reduction may be present in segments of the cochlea with normal-appearing hair cells. CONCLUSIONS: The study suggests that aminoglycoside antibiotics can injure spiral ganglion cells directly, as well as hair cells. Thus, the characteristic hearing loss of ototoxicity can result from degeneration of either cochlear element.
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8/32. Ramsay Hunt syndrome: pathophysiology of cochleovestibular symptoms.

    Ramsay Hunt's hypothesis that herpes zoster oticus results from reactivation of the varicella zoster virus (VZV) in the geniculate ganglion is supported by the detection of viral genome in archival temporal bones of normals and Ramsay Hunt patients by the polymerase chain reaction. Ramsay Hunt syndrome is characterized by the presence of cochleovestibular symptoms in association with facial paralysis. VZV has also been demonstrated in the spiral and/or vestibular ganglion. Two cases are reported in which cochleovestibular symptoms outweighed the facial nerve symptoms, presumably representing VZV reactivation in the spiral and/or vestibular ganglion. From these observations and the known dormancy of VZV in non-neuronal satellite cells, it is argued that the cochleovestibular symptoms in Ramsay Hunt syndrome may result from VZV transmission across the nerves inside the internal auditory canal and that prompt treatment with an antiviral-corticosteroid combination might be justified in the management of any acute non-hydropic cochleovestibular syndrome.
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9/32. Canavan's leukodystrophy is associated with defects in cochlear neurodevelopment and deafness.

    The authors present the temporal bone histopathology of two siblings (4 months old and 6 months old at autopsy) with Canavan's disease, an autosomal recessive leukodystrophy that is variably associated with sensorineural hearing loss. The histopathology demonstrated bilateral absence of the organ of corti throughout the apical and basal cochlea and mild secondary atrophy of the spiral ganglia neurons. The vestibular end organs and ganglia were normal. These findings implicate a role of aminoacylase II in the neurodevelopment of the organ of corti.
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10/32. temporal bone histopathological and quantitative analysis of mitochondrial dna in MELAS.

    OBJECTIVES/HYPOTHESIS: Although hearing loss is common in MELAS (syndrome of mitochondrial encephalopathy, lactic acidosis and stroke-like episodes), the histopathology of the temporal bone has not been reported. The majority of cases of MELAS are linked to a mitochondrial dna (mtDNA) mutation at nucleotide 3243. In MELAS, normal mtDNA and mutant mtDNA coexist in a heteroplasmic manner. The purpose of the study was to report the otopathological findings from two patients with MELAS and quantitative mtDNA analysis in the inner ear of one of these patients. STUDY DESIGN: Basic scientific histopathological examination and quantitative mtDNA analysis of the temporal bone. methods: Temporal bones were embedded in celloidin and sectioned for light microscopic study. Graphic reconstruction of the cochlea was performed using the method described by Schuknecht. For quantitative mtDNA analysis, total dna from the membranous part of the inner ear was collected, amplified by polymerase chain reaction, and digested with the restriction enzyme. The percentage of mutant/total mtDNA was measured by the ratio of fluorescence intensity. RESULTS: Histopathological examination revealed severe degeneration of the stria vascularis and degenerative change of spiral ganglion cells in both patients. The quantitative dna studies showed that the proportion of mutant to wild-type mtDNA was similar in both histologically affected and histologically unaffected tissues within the inner ear. CONCLUSION: Dysfunction of the stria vascularis and spiral ganglion cells causes sensorineural hearing loss in MELAS.
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