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At least 397 records · Page 22Linked to original sources
PubMed1992

Microvasculature of normal and hydropic labyrinth.

The microvasculature of the inner ear in guinea pigs and humans was observed with a scanning electron microscope using corrosion casting method. Alterations in the inner ear vasculature which occurred in association with experimental endolymphatic hydrops were also investigated. The results thus obtained are summarized as follows: 1. In the cochlea and vestibule, the arteries, coiled arterioles, and the veins are endowed with their respective characteristic morphologic features and play a role in the regulatory mechanisms of circulation. 2. The point in humans which is most different from guinea pigs was that coiled arterioles in the cochlea and the coil-like traveling of the anterior vestibular artery is not outstanding. 3. Arteriovenous anastomoses were demonstrated to exist in lateral wall of cochlea and utricular macula, a finding suggesting the existence of a regulatory mechanism for local blood flow. 4. Endolymphatic hydrops was noted to be preferentially associated with vascular abnormalities in the lateral wall of the cochlear duct and in the saccular macula, among other vestibular structures.

Animals↗
PubMedDate not supplied

Double-blind study on the effectiveness of a bioflavonoid in the control of tinnitus in otosclerosis.

Ipriflavone (7-isopropoxy-isoflavone) was attempted to relieve tinnitus of otosclerotic patients prior to stapedectomy and continuing the treatment postoperatively in a 6 months regimen. As a whole the double-blind study revealed effectiveness of Ipriflavone in the control of tinnitus when preoperatively administered as well as in combination with stapedectomy. The small number of cases (9 patients treated with Ipriflavone and 7 patients with placebo) needs further confirmation of the present data. Predominantly low-tone tinnitus rises the possibility of its cochlear origin in otosclerosis, as a consequence of mechanical or hydrodynamic causes or hydrostatic pressure elevation due to spread of the otosclerotic focus onto the cochlear duct.

Adult↗
PubMed2006

The development of the spiral ganglion in the human foetus.

The development of the spiral ganglion was studied in steps sections of 81 human temporal bones. By the 8th week, the spiral ganglion has already separated from the vestibular ganglion. At 13 weeks two distinct populations are observed that correspond to neuron and Schwann cells. At 15 weeks the spiral ganglion has increased its distance from the cochlear duct and is surrounded by mesenchyme near the scala tympani. At 14 weeks a gradual decrease in the nucleus-to-cell area ratio was observed in spiral ganglion neurons that may reflect a morphological adaptation to function. By the 23rd week the modiolus begins to ossify and the spiral ganglion is surrounded by bony trabeculae. The time course of spiral ganglion development follows that of the stria vascularis and organ of Corti, although maturation changes are still observed in the neuronal population even beyond 20 weeks.

Cell Nucleus↗
PubMed1991

[Electrocochleography in experimental animal model with acute hydrolabyrinth].

A desirable animal model of acute hydrolabyrinth was made by injecting artificial endolymph into the cochlear duct of guinea pigs. In 12 animals with intact Reissner membranes, the endolymphatic potential kept normal after injection of artificial endolymph, but their ECochG showed a rise of SP amplitude, a decrease in AP amplitude, an increase of SP/AP ratio, and a delay of N1 latency. In 7 animals with ruptured membranes, the EP significantly decreased. ECochG showed a decrease in hearing in all test frequencies, a distortion of SP-AP wave or even a loss of AP. Based on the results of our experiment, it can be assumed that the dominant -SP may be seen in the acute stage of endolymphatic hydrops without a rupture of Reissner membrane. Therefore, the dominant -SP may only be of value in the clinical diagnosis during an episodic vertigo and fluctuating hearing loss in Ménière disease.

Animals↗
PubMedDate not supplied

The effect of injection of high K+ solution into scala media.

Thirty guinea pig ears were studied to investigate the effect of endolymphatic hydrops on the cochlea. High K+ solution was injected into the scala media, and cochlear microphonics (CM) and endocochlear potential (EP) were observed before, during and after the injection. The CM amplitude decreased rapidly after injection, ending in a depressed plateau value. By contrast, EP remained almost unchanged. By changing the composition of the solution it was suggested that the effect of the injection was mechanical one, rather than biochemical. In three ears, spontaneous recovery of CM was observed during a relatively long interval after the injection. The meaning of these findings for the hearing loss in Meniere's disease is discussed.

Animals↗
PubMed1985

The cochlear nuclei--pathology.

This article is a sequel to one dealing with the anatomy of the cochlear nuclei. It employs the combined peripheral/central approach in reviewing some basic principles of the pathology of central deafness, involving the cochlear nuclei. The combined approach shows the relative status of the cochlear elements and of the superior ventral cochlear nucleus in various conditions. Anoxic encephalopathy, including that of erythroblastosis, involves the stated nucleus but spares the peripheral hearing organ. This, as well as the findings in other conditions, reflects on the employment of amplification or the implantation of electrodes. The spheroid cells, the nerve cells of concern of the superior ventral cochlear nucleus (SVCN), show an anatomic frequency gradient, low ventral to high dorsal. In any case of deafness expected to involve the SVCN and showing an audiogram frequency pattern, the frequency gradient must be included in the pathologic investigation. When the organ of Corti is completely destroyed, the spheroid cells may show transsynaptic atrophy.

Aged↗
PubMed1973

The stria vascularis after ultrasonic irradiation.

The cochleae of 51 guinea pigs were exposed to focused ultrasound of 1.25 megacycles. The ultrasonic probe, with a tip area of 1.8 mm2 was gently positioned against the otic capsule at the third coil from the base for 3 minutes at an intensity of 20 W/cm2. The only variable factor in this study was the survival time which was selectively set between 12 hours and 2 months. The stria vascularis was stained by the peroxidase-benzidine method. Circumscribed lesions of rather uniform character were found. The acute changes consisted of vascular constriction, thrombus formation, disruption and extravasation of blood. After survival times of one and two months, all vessels within a small segment of the spiral ligament and the stria vascularis had disappeared. No definite signs of revascularization of the target area were observed. Most of the pigment granules of the stria vascularis were dissolved within the treated zone. The effects of focused ultrasound and argon laser irradiation upon the vessels in the lateral wall of the cochlear duct have been compared.

Animals↗
PubMedDate not supplied

Mondini dysplasia; a clinical and pathological study.

Mondini dysplasia is characterized by bony and membranous anomalies of the inner ear exhibiting a wide range of morphological and functional abnormality. Typically the cochlea is flat, the cochlear duct is short, the auditory and vestibular sense organs and nerves are immature, the vestibule is large, the semicircular canals are wide, small or missing and the endolymphatic sac is bulbous. Incomplete expressions of the disorder may occur with little or no loss of auditory or vestibular dysfunction, while severe forms show no hearing or vestibular response. The disorder may occur in association with anomalies in other organs, such as in Klippel-Feil syndrome. Pendred's syndrome, trisomy syndrome, and DiGeorge's syndrome, or it may occur in isolation. It may occur in one or both ears and is readily diagnosed by polytomographic radiologic studies. In some cases the footplate of the stapes is partly or totally replaced by a thin membrane which may rupture and lead to spontaneous CSF otorrhea and meningitis. The quality of auditory and vestibular function will determine the method of surgical closure. Usually ears developing such fistulae have no auditory function and the leaks are permanently stopped by simply introducing an autogenous soft tissue graft through the oval window into the vestibule.

Abnormalities, Multiple↗
PubMedDate not supplied

Cochlear and otoconial abnormalities in capsular otosclerosis with hydrops.

Temporal bones from four patients with capsular otosclerosis were examined by microdissection. Otoconia and abnormal crystalline deposits were studied by scanning electron microscopy and x-ray analytical methods. One patient showed more or less symmetrical invasion of the basilar membrane and osseous lamina by connective tissue from thickened endosteum adjacent to the larger anterior foci. In one ear sensorineural degeneration was circumscribed; in the other it was extensive and associated with cochleosaccular hydrops. Two other patients were deaf, with severe sensorineural degeneration; one had multiple active foci and evidence of cochleosaccular hydrops. In the fourth patient, who had small anterior foci, no specific inner ear pathology was found related to otosclerosis. In the hydropic labyrinths, apatite was present as abnormal deposits in the cochlear duct and as rigid crusts replacing the otoconia. Apparently these changes had been associated with abnormal labyrinthine fluid dynamics rather than with the otospongiotic process per se.

Aged↗
PubMed1983

Cochleostomy or endolymphatic sac surgery for advanced Meniere's disease.

The operation of cochleostomy is described. The surgical technique is vital for the true assessment of results. If the cochlear duct is punctured, the risk to hearing is unacceptably high. If only the osseous spiral lamina is punctured, the results are acceptable in the short term, though the rationale cannot be explained. In the management of difficult patients with more advanced Meniere's disease, some variant of cochleostomy should probably be included in the therapeutic options. The results of endolymphatic sac surgery are significantly better in a matched group of patients.

Cochlea↗
PubMed1981

[Temporal bone histopathology in a case of trisomy 22-syndrome (author's transl)].

This premature female infant died soon after birth. She had numerous gross anomalies and was found on cytogenic studies to have Trisomy 22. Polytomographic and histologic studies of the left ear revealed multiple anomalies including complete aural atresia, non-pneumatization of the middle ear with a vertical shelf of bone in the mid portion of the middle ear, absence of the stapes and oval window and bony closure of the round window niche. The cochlea is flat in shape and shows one and a half turns with incomplete formation of the modiolus. The intersaccular septum is rudimentary but the spiral ganglion is clearly seen in Rosenthal's canal through the one and a half turns. The organ of Corti is well developed and contains hair cells. The stria vascularis is present. The utricular and saccular maculae as well as all cristae are well developed and contain hair cells. The saccular wall is collapsed onto an atrophic appearing otolithic membrane. The utricle is dilated, the lateral semicircular canal appears short and the bony canal is wide. The flattened and shortened cochlea with deformities of the cochlear duct, and the large vestibule resembles Mondinis dysplasia.

Abnormalities, Multiple↗
PubMed1978

[Peroxidase distribution pattern and cochlear microphonics in the impulse-noise exposed cochlea of the guinea pig (author's transl)].

Morphological findings evidenced the impulse noise trauma primarily a mechanical lesion of cells. The loss of mechanically damaged sensory cells results in the initial decline of cochlear microphonics. Due to mechanical lesions many sites of leakage in the wall of the cochlear duct give way to the diffusion of components of either lymph, which will produce a general functional disturbance associated with additional decline of microphonics. The functional restoration of the inner ear requires the previous repair of the endo/perilymphatic barrier.

Animals↗
PubMed1980

Pressure sensation in Meniere's disease.

This article reports a case of Meniere's disease accompanied by a persistent feeling of pressure in the ear. The patient had undergone a series of surgical procedures to alleviate his symptoms. The pressure sensation was relieved only by translabyrinthine cochlear nerve section. The relationships of the result of translabyrinthine cochlear nerve section with the mechanism and pathway of the pressure sensation are discussed. Cochlear nerve section is recommended at the same time as vestibular nerve section for patients with unilateral Meniere's disease with severe pressure sensation in the ear.

Adult↗
PubMed1993

[Variations of the stereociliary bundles of the outer hair cells in guinea pigs. A scanning electron microscopic study].

Variations of the stereociliary bundles of the outer hair cells in guinea pigs observed under scanning electron-microscope were reported. Changes including transposition and distorted outlines of the stereociliary bundles were distributed in all turns of the cochlear duct and all rows of the outer hair cells, but not in inner hair cells. The possible pathogenetic significance of the changes was discussed.

Animals↗
PubMed1996

Co-culture of contiguous developmental fields in a serumless, chemically-defined medium: an in vitro model permissive for coordinate development of the mouse ear.

Pattern formation is intrinsically hierarchical, increasing in complexity from the first early embryonic inductive tissue interactions to the eventual integration of multiple organ systems. Viewed as a problem in pattern formation, the vertebrate ear is an exceedingly complex organ system in which normal morphogenesis requires multiple inductive interactions between a variety of adjacent tissues. In order to model the process of higher level pattern formation, we have developed a method for organ culture of the embryonic murine ear. E10.5 mouse embryos (38 to 42 somite pairs) were microdissected into explants that consist of the first and second branchial arches, the otocyst, and the adjacent neural tube. The growth of these explants in a serumless, chemically-defined medium was compared to medium supplemented with 10% fetal calf serum. After 6 days in culture using serumless medium, we observed that this environment was permissive for the formation of pinnae, rudimentary semicircular canals and cochlear ducts, chondrogenesis of the otic capsule and elongation of the endolymphatic ducts. Posterior elements of Meckel's and Reichert's cartilages were identified as ossicular anlagen. All of these structures maintained appropriate anatomic interrelationships during in vitro development. Furthermore, no significant differences were observed in explants grown in serum-supplemented medium. We conclude that during ear development several histogenetic and morphogenetic processes, including aspects of higher level pattern formation, are mediated primarily by paracrine and/or autocrine factors. The development of an organ culture model using serumless medium should facilitate the discovery of intrinsic factors which regulate the coordinate development of inner, middle and external ear structures.

Animals↗