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At least 1,621 records · Page 90Linked to original sources
PubMed1977

Experimental cytomegalovirus infection and the developing mouse inner ear: in vivo and in vitro studies.

Mouse cytomegalovirus causes perilabyrinthitis in the cochlea following intracranial inoculation of the newborn mouse. In spite of infection of cranial nerve ganglion cells and Schwann cells the organ of Corti achieves normal adult morphology including efferent nerve endings. No involvement of neuroaxons is seen. In comparison human cytomegalovirus infection causes endolabyrinthitis without involving periotic connective tissues or nerves even in the presence of meningoencephalitis. The lack of epithelial infection and susceptibility of periotic connective tissues to mouse cytomegalovirus was confirmed by infection of fetal mouse otocysts in organ culture. The mouse model of cytomegalovirus ear infection shows greater similarities to other herpesvirus infections of the ear such as varicella-zoster than to human cytomegalovirus and thus remains extremely useful for the study of herpetic neuronal and ear infection.

Animals↗
PubMed1991

Inner ear morphologic changes resulting from cochlear implantation.

Insertion of electrodes into the cochlea can damage the spiral ligament, organ of Corti, osseous spiral lamina, and dendrites. The amount of damage depends on the method of insertion and the amount of surgical trauma. Damage is limited to the area immediately adjacent to the electrode. Damage in the cochlea and prolonged electrical stimulation do not affect ganglion cell population. The ganglion cell population responds directly to the electrical stimulus. Examination of three auditory nerves from three cases and the cochlear nuclei from one case also reveals no effect of prolonged electrical stimulation.

Cochlear Implants↗
PubMed1990

Scanning electron microscopy of the celloidin-embedded inner ear sections.

The nerve fibers running inside the organ of Corti were studied in cats by scanning electron microscopy (SEM). The fixed temporal bones were decalcified and embedded in celloidin according to the conventional method. Thick serial sections (100-150 microns) were cut parallel to the basilar membrane. After removing the celloidin, the sections were freeze-dried in t-butyl alcohol. Though some outer hair cells had been deformed, the nerve fibers were well preserved for analysis. Some new findings were observed in the present SEM study. The tunnel spiral bundle in a kitten took an atypical course on the floor of Corti's tunnel apart from the previously reported site. In the barely-patent tunnels of Corti in kittens, nerve fibers were stuck together into thick bundles and took different courses compared to those in the mature cochleas. Filiform projections of nerve fibers were climbing around the first row of the outer hair cells in the immature cochlea. These were thought to be growing ends of efferent nerves which would later grow into nerve endings.

Animals↗
PubMed1987

[Processing of acoustic stimuli in the inner ear--a review of recent research results].

This review presents recent findings on the micromechanics of the basilar membrane. Active processes are essential for basilar membrane motion. It may be that contractile proteins within the outer hair cells play an important role for this amplification. The coding of acoustic information within the auditory nerve depends on spectral analysis (place information) as well as on the time structure of the stimulus. This latter time analysis seems to play a major role.

Auditory Threshold↗
PubMed1989

Perfusion of the inner ear with streptomycin.

Any medical or surgical treatment of Meniere's disease is always suspect because the natural history is so variable and the pathologic physiology is not well-known. Even the occurrence rate in one and both ears is not known. It is certainly true that endolymphatic hydrops, caused by the failure of absorption of endolymph in the endolymphatic sac, is the principal pathology in the classical, fully developed Meniere's disease. While the endolymphatic shunt operation is correct in theory, in most ears, it does not work because the surgeon does not always locate the lumen of the sac and when located, the shunt tube does not remain open. While vestibular neurectomy is more likely to give permanent relief of vertigo as compared to the endolymphatic sac operation, the operation is difficult and dangerous and does nothing for the hearing. The vestibulotoxic action of the aminoglycocide antibiotics, especially streptomycin, when introduced into the perilymph of the lateral semicircular canal will destroy the vestibular receptors without making the hearing worse, and by acting on the dark cells, reduce the production of endolymph. Perfusion of the perilymph with streptomycin through an opening in the bony lateral semicircular canal is the operation of choice for Meniere's disease, benign paroxysmal postural vertigo and other forms of vertigo. So far 66 such operations have been done during the last three years with very encouraging results.

Aged↗
PubMed1988

Glutaraldehyde induces cell shape changes in isolated outer hair cells from the inner ear.

Individual isolated outer hair cells (OHCs) from the cochlea were maintained in a collagen gel and viewed in the light microscope. They were observed during fixation and processing for transmission electron microscopy and individual cells were selected for observation in the electron microscope. Application of glutaraldehyde at several concentrations caused OHCs to become shorter. Shrinkage occurred during dehydration but there was no further change during infiltration with the epoxy resin. Ultrastructural analysis of isolated cells fixed with glutaraldehyde and postfixed with osmium tetroxide showed that these cells were similar to cells fixed in the intact cochlea. The glutaraldehyde-induced cell shape change is similar to the shortening seen in intact OHCs in response to the application of solutions containing high potassium or caffeine. Application of glutaraldehyde to cells pretreated with potassium or caffeine caused further shortening. Glutaraldehyde-induced cell shape change was not blocked by the application of tetracaine, which did prevent potassium-induced and caffeine-induced shortening. Glutaraldehyde-induced cell shape change was not stopped by short treatment with N-ethylmaleimide, which did inhibit potassium-induced shortening. Results from these experiments suggest that the glutaraldehyde-induced OHC shape change is not caused by an effect on the membrane or by calcium activation of a contractile response. Shortening may be caused by shrinkage due to cross-linking of proteins.

Aldehydes↗
PubMedDate not supplied

Alleged inner ear trauma: compensation pending.

The English literature on the incidence of nystagmus in normal subjects and in patients with head and/or neck injuries is reviewed. The authors present a series of 202 patients with alleged vestibular trauma. The incidence of spontaneous and positional nystagmus would seem to be no greater in patients with alleged vestibular trauma than that found in the normal subjects, suggesting that these patients do not have objective evidence of vestibular trauma. Objective criteria for diagnosing vestibular abnormalities by electronystagmography are presented. At least 22% of a series of 2408 patients were found to have a functional hearing loss. The importance of looking for functional overlay in patients involved in litigation cases is stressed.

Adolescent↗