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At least 1,063 records · Page 59Linked to original sources
PubMed1975

Pathologic features of the inner ear in congenital deafness.

We present the morphologic findings of the temporal bones and brain of a patient with congenital deafness. We discuss these findings in relation to pathologic observations in other reported cases of congenital deafness. Morphologic abnormalities in the patient were mainly in the pars inferior of the membranous labyrinths. The osseous labyrinths were well developed. There was severe dilation of the cochlear duct with herniation of the Reissner membrane, extensive atrophy of the stria vascularis that was associated with calcified thrombi to the strial vessels, encasement of the tectorial membrane in a syncytium, and dyspiastic or regressive degeneration of the organ of Corti. Absence of spiral ganglion cells and their fibers was a prominent feature. The extensive and varied pathologic changes that were present in our patient simultaneously suggest a congenital abnormality in endolymph production and raise the possibility of anomalous development of the labyrinthine vasculature.

Aged↗
PubMed1976

Inner ear pathologic features following mumps infection. Report of a case in an adult.

Temporal bone studies in an adult with a moderately severe, bilateral sensorineural hearing loss revealed bilateral cochlear changes 13 years after mumps infection. The organ of Corti was completely absent in the greater part of the superior horizontal basal limbs, with occasional hair cell loss throughout the rest of the cochlea. The outer sulcus cell area was degenerated. The stria vascularis was normal, as was the tectorial membrane, except for small hyaline droplets. The number of nerve fibers was extremely decreased in the spiral bony lamina of the basal turns. Basophilic material, possibily representing degeneration of otoliths, was present in the saccule and utricle, bilaterally, with small amounts in all of the ampullae. This was considered to be either a possible result of cytotoxic cancerocidal therapy, or an incidental nonspecific change.

Adult↗
PubMed1999

Characterization of ootolith soluble-matrix producing cells in the saccular epithelium of rainbow trout (Oncorhynchus mykiss) inner ear.

Although the organic matrix may play an important role in the growth of teleost otoliths, cellular contributions to the production of the organic matrix have been studied in only a small number of teleost species with limited methods, and are still poorly understood. In order to characterize saccular epithelial cells which produce otolith matrix, antiserum was raised against an EDTA-soluble fraction of otolith matrix (otolith soluble-matrix, OSM) of the rainbow trout. The components in the OSM and in the endolymph were characterized by immunoblotting. The saccular epithelium was immunohistochemically stained with the antiserum and the ultrastructure of OSM immunoreactive cells was studied. By immunoblotting, multiple components (> 94.0 kDa [smeared] and 43.0 kDa) in the OSM reacted with the antiserum, whereas only one band (> 94.0 kDa) was detected in the endolymph. Under immunohistochemical staining, reactions to the antiserum were observed in columnar cells lined at the most peripheral region of the sensory epithelium, transitional epithelial cells, and squamous epithelial cells. Electron microscopic observations revealed that all three types of cells were equipped with extended rough endoplasmic reticulum and prominent Golgi apparatus, suggesting the active production of organic material(s). Dilations of translucent vesicles, apocrine-like extrusions of cytoplasm, and vesicles containing many minute globules were frequently associated with the apical surface of these cells. Some ruptured vesicles were observed, releasing their contents into the endolymphatic space. The present study identified columnar cells lining the most peripheral region of the sensory epithelium, transitional epithelial cells, and squamous epithelial cells as the OSM-producing cells. We suggest that the OSM components are secreted and dissolved into the endolymph and subsequently deposited onto the otolith.

Animals↗
PubMed2001

CHARGE association with choanal atresia and inner ear hypoplasia in a child with a de novo chromosome translocation t(2;7)(p14;q21.11).

A 3-year-old boy was diagnosed with CHARGE association on the basis of bilateral choanal atresia, absence of the semicircular canals, hypoplastic cochleae, genital hypoplasia, growth and developmental delays, cranial nerve dysfunction, and facial anomalies. Ophthalmologic and cardiac evaluations were normal. He was found to have an apparently balanced t(2;7)(p14;q21.11) chromosomal translocation. Parental karyotypes were normal. Although there is evidence suggesting a genetic basis for CHARGE association, individuals with chromosomal abnormalities and CHARGE are rare. In the described patient, the presence of characteristic CHARGE features suggests that the t(2;7)(p14;q21.11) translocation breakpoints may cause a deletion or disruption of genes within the involved regions that are involved in the generation of the CHARGE association phenotype.

Abnormalities, Multiple↗
PubMed1976

Tight and gap junctions in a vertebrate inner ear.

The auditory organ of the alligator lizard has been investigated with the transmission electron microscope using methods which distinguish between tight and gap junctions. There is a continuous zone of tight junctions located near the endolymphatic surface of the organ forming a boundary between the endolymph in scala media and the interstitial spaces between the cells. No such tight junctions were observed between the perilymph of scala tympani and the interstitial fluid within the organ. Small gap junctions occur between hair cells and supporting cells and large gap junctions occur between adjacent supporting cells. The locations of the tight junctions suggest that the composition of the intercellular fluid in the receptor organ is probably more like perilymph than like endolymph. The presence of gap junctions between hair cells and supporting cells provides a possible morphological basis for the occurrence of intracellular responses to sound in supporting cells, and for elctric coupling of receptor cells.

Animals↗
PubMed2005

How can teleostean inner ear hair cells maintain the proper association with the accreting otolith?

The perception of equilibrium and sound in fish depends on the deflection of hair bundles of hair cell by the otolith. However, the accreting nature of teleostean otoliths poses a problem for maintenance of proper contact between the hair bundle and the otolith surface. Immunocytochemical staining localizes abundant proton-secreting H(+)-ATPase in the apical membrane of the hair cells. The H(+)-ATPase-mediated proton secretion into the endolymph causes an approximately 0.4-unit pH decrease, which was quantified by an H(+)-selective microelectrode. Thus, the hair cells maintain the proper distance from the otolith by neutralizing the alkaline endolymph to retard CaCO(3) deposition on the otolith opposite the sensory macula. Carbonic anhydrase, which hydrolyses CO(2) and produces HCO(3) (-) and H(+), was also localized in the hair cells. Ionocytes showed prominent immunostaining of carbonic anhydrase and Na(+)-K(+)-ATPase, indicating its role in transepithelial transport of HCO(3) (-) across the membranous labyrinth into the endolymph. Ionocytes form a ring closely surrounding the sensory macula. HCO(3) (-) secreted from the ionocytes may serve as a barrier to neutralize H(+) diffused from the sensory macula while keeping the endolymph alkaline outside the sensory macula. The ingenious arrangement of ionocytes and hair cells results in a unique sculptured groove, which is a common feature on the proximal surface of all teleostean otoliths.

Animals↗
PubMed1983

Organization of eighth nerve afferent projections from individual endorgans of the inner ear in the teleost, Astronotus ocellatus.

Eighth nerve fibers from the saccule, utricle, lagena, and the anterior, horizontal, and posterior semicircular canals of a cichlid fish were traced to the octavolateralis region of the brainstem using HRP and degeneration methods. The anterior, magnocellular, descending, and posterior nuclei of the octavus column receive inputs from all endorgans, whereas the tangential nucleus receives projections only from the utricle and semicircular canals. The most rostral projections only from the utricle and semicircular canals. The most rostral projection from each endorgan is found in the eminentia granularis of the vestibulolateral lobe of the cerebellum. Sparse terminals are found in the medial reticular formation from the utricle adn semicircular canals, and utricular and saccular remain terminate in the vicinity of the lateral dendrite of the Mauthner cell. Utricular and semicircular canal projections consistently overlap centrally as do saccular and lagenar inputs. Afferent fibers from all endorgans end within relatively distinct regions throughout the octavus column of nuclei. Saccular and lagenar inputs lie dorsal to the semicircular canal terminations. Utricular endings are complex, however, in that they overlap dorsally with saccular and lagenar terminals and ventrally with the semicircular canal inputs. Cerebellar inputs are found only in the eminentia granularis of the vestibulolateral lobe, and the densest terminals are from the utricle and the semicircular canals; the sparsest are from the saccule. Previous studies in fish have indicated that generally the utricle and semicircular canals are concerned with he maintenance of static and dynamic equilibrium whereas the saccule and lagena are concerned with auditory reception. There is recent evidence, however, for multiple functions within individual endorgans. Our anatomical findings suggest that in Astronotus each otolithic endorgan carries more than one modality; that the semicircular canals are concerned solely with an equilibrium function; and that acoustic information is processed dorsally and vestibular information ventrally along the octavus column of nuclei. No single nucleus appears to be solely auditory in function and only the tangential nucleus, situated ventrally in the octavus column, appears to be solely vestibular.

Afferent Pathways↗
PubMed1992

Ultrastructure of hyaline, border, and vacuole cells in chick inner ear.

The sense organ for hearing in birds, the basilar papilla, is capable of replacing lost or damaged hair cells and supporting cells through regeneration. Potential candidates for precursor-cell populations include cells within the auditory receptor epithelium and nonsensory cells inferior to the sensory epithelium. Ultrastructural characteristics of hyaline cells, border cells, and vacuole cells, nonsensory cells which border or lie inferior to the receptor epithelium proper, were studied with transmission electron microscopy. Data were obtained from normal neonatal and adult chickens. Several rows of epithelial cells separate hyaline cells from inferiorly located organ supporting cells and hair cells. Ultrastructural characteristics and location of these epithelial cells differentiate them from organ supporting cells and hyaline cells; consequently, we have termed them "border cells." Synaptic specializations are observed between neural elements and border cells, and gap junctions are found between adjacent border cells, between border cells and neighboring organ supporting cells, and between juxtaposed border and hyaline cells. Hyaline cells, in contrast to border cells, are highly specialized. Dense bundles of filaments are present in hyaline cells from the basal one-half of the papilla, and an unusual structure, a rough tubular aggregate, is present in hyaline-cell cytoplasm. Pre- and postsynaptic specializations are observed between neural elements and hyaline cells, and gap-junctional complexes link neighboring hyaline cells. Vacuole cells lie inferior to the hyaline cells and rest on the inferior fibrocartilaginous plate. They are unspecialized morphologically. Their only remarkable morphological feature is the abundance of spherical vacuoles within their cytoplasmic matrix.

Animals↗