This study assesses several electrocochleographic (ECoG) duration and amplitude measures in a clinically defined Meniere's group and compares the results with those from a normal hearing control group and a hearing loss group (cochlear). The summating potential (SP)/action potential (AP) amplitude ratio was the most efficient diagnostic measure, with 62% of the Meniere's group demonstrating abnormal ratios compared to 4% of the normal control group and 17% of the cochlear group. The SP changes were then studied from three angles: 1. Comparison of SP changes with glycerol test results; 2. Comparison of ECoG results before and after shunt surgery; and 3. Recording of SP's in guinea pig ears in which hydrops had been created by obliterating the endolymphatic duct.
Vertebrate lateral line and vestibular systems center their function on highly mechanosensitive hair cells. Each hair cell is equipped with one kinocilium (which resembles a motile cilium) and 50-100 actin-containing stereocilia (which resemble microvilli) at the site of stimulus reception. This report describes electron-microscopic localization of calcium-binding sites on the sensory processes ofvertebrate hair cells. Using the Oschman-Wall technique for calcium localization [Oschman, J. L. & Wall, B. J. (1972) J. Cell Biol. 55,[58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73] together with electron-probe x-ray microanalysis of thin sections, we observed: (i) calcium-and ironcontaining deposits in the region of the ciliary necldace in goldfish lateral line hair cells, (ii) calcium deposits upon the surface of stereocilia of hair cells of the bullfrog inner ear, and (iii) calcium deposits upon stereocilia of hair cells of the guinea pig vestibular system.Vertebrate lateral lines and vestibular systems are equipped with hair cells of exquisite mechanosensitivity (1). Hair cells, capable of responding to a 0.5-nm stimulus (2) in less than 40 ,usec (3), are fitted with a single kinocilium and 50-100 microvillous "stereocilia" at the site of stimulus reception. It is interesting to note that the kinocilium, which resembles a "9+2" motile cilium, and the microvillous stereocilia, which contain core filaments of actin (4, 5), are both derived from primitive motile systems.Throughout the course of evolution, locomotor and sensory systems have been closely allied. Because ciliary and actinbased motile systems are, in part, activated and regulated by calcium ions, we ask: are calcium-binding sites associated with the kinocilia or stereocilia of vertebrate hair cells?Using the Oschman-Wall technique of calcium localization (6) in concert with electron-probe microanalysis ofthin sections, we have observed calcium-binding sites on the sensory cilia of hair cells of the goldfish lateral line, the bullfrog vestibular system, and the guinea pig vestibular system. MATERIALS AND METHODS Source of Tissues. Sense organs from the acousticolateralis system of animals from three vertebrate classes-a teleost fish, an amphibian, and a mammal-were studied. Mechanoreceptive hair cells within the following sense organs were investigated: (i) hair cells from the supraorbital canal of the lateral line system ofthe goldfish, Carassius auratus; (ii) hair cells from the macula sacculi of the vestibular system of the bullfrog, Rana catesbeiana; and (iii) hair cells from the macula sacculi and macula utriculi of the vestibular system of the guinea pig, Cavia porcellus.Electron Microscopy. Tissues were fixed by following the method of Oschman and Wall (6), a preparative procedure that localizes sites on cell membranes that have a high affinity for calcium ions. Experimental tissues were fixed overnight at 40C in a solution containing 2.7% (vol/vol) glutaraldehyde, 5% sucrose, and 5 mM CaCl2 buffered to pH 7.2 with 0.08 M ...
Horseradish peroxidase was injected into the foramen magnum and oval window of guinea pigs to determine perilymphatic communication routes and boundaries. The primary route to the auditory system appeared to be through the cochlear aqueduct. Perineural spaces of the eighth nerve contributed to this communication and provided the principal perilymphatic communication routes to the vestibular system. Light and electron microscopic examination were used to identify membrane permeability and define boundaries in the epithelial lining of the auditory and vestibular endorgans.
To discover whether removal of the canal wall would reduce the incidence of postoperative cholesteatoma in tympanoplasty, the findings in staged, intact canal wall tympanoplasties were compared with those in staged, modified radical mastoidectomies with cavity obliteration and tympanoplasty. In all, cholesteatoma was considered totally removed at the first operation. The incidence of residual cholesteatoma was not significantly different in either group. It is concluded that staging in tympanoplasty for cholesteatoma is mandatory.
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