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Tono T, Morizono T. Low-frequency biasing of round window responses in guinea pigs and chinchillas. AUDIOLOGY : OFFICIAL ORGAN OF THE INTERNATIONAL SOCIETY OF AUDIOLOGY 1995; 34:47-56. [PMID: 7487646 DOI: 10.3109/00206099509071898] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The acoustic biasing technique using low-frequency sound is of increasing interest to investigators, not only as a means of studying cochlear transduction but also as a promising tool for assessing cochlear pathology such as endolymphatic hydrops. We compared normal modulation patterns of round window responses in guinea pigs and chinchillas, whose low-frequency auditory characteristics are known to be different. A 50-Hz sine wave (90 dB SPL for guinea pigs and 80 dB SPL for chinchillas), which evoked an equivalent magnitude of cochlear microphonics (CM) in both species, was used to modulate the compound action potential (CAP) and the summating potential (SP) elicited by 8-kHz tone bursts. Overall patterns of CAP and SP modulation were almost identical between the two species except for a difference in the phase of 50 Hz CM. The phase of maximum SP enlargement was in accord with that of maximum CAP suppression, which led to inferred basilar membrane (BM) position at maximum scala tympani displacement by between 45 and 90 degrees. More complex or hysteresis effects seemed to be involved in the modulation of CAP and SP magnitude, in addition to the biasing effect owing solely to BM displacement.
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Kato T, Shiraishi K, Harada H, Yoshimine K, Morizono T, Soda T. A device for controlling odorant stimulation and olfactory evoked responses in humans. Auris Nasus Larynx 1995; 22:103-12. [PMID: 7487670 DOI: 10.1016/s0385-8146(12)80108-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We developed a device for odorous stimuli control to record olfactory evoked responses from the human scalp. The characteristics of the apparatus are as follows. Translating the subject's respiration into electric signals with a sensor attached to the nose. The period and timing of odorous stimuli could be adjusted, so that stimuli could be synchronous with respiration. The interstimulus interval could be arbitrarily selected once every 1 to 9 respiration(s) so that adaptation could be prevented. We obtained evoked responses to odorous stimuli using this apparatus from the human scalp, whose positive peak latencies were approximately 350 and 700 msec. Such responses were not recorded if oxygen stimuli were used instead of odorous stimuli or with click sounds produced by the switching electromagnetic valve. Three types of odorant evoked scalp potentials were obtained in normal human subjects. The first type consisted mainly of two positive peaks with a peak latency of about 350 msec (P350) and about 700 msec (P700). The second type and the third type consisted of only one positive peak with a peak latency of about 350 msec and 700 msec, respectively. Such a P350 or P700 peak as that observed in the normal subjects was not detected in anosmic patients.
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Kato T, Kimura K, Shiraishi K, Eura Y, Morizono T, Soda T. Topography of binaural interaction in the auditory brainstem response. Auris Nasus Larynx 1995; 22:145-50. [PMID: 8561694 DOI: 10.1016/s0385-8146(12)80051-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The scalp topography of binaural interaction (BI) in the auditory brainstem response (ABR) was studied in fourteen normal individuals. BI was observed from all recording sites of the scalp, and the peak amplitude was noted mostly in the bilateral parietal and occipital regions. There was a significant difference in amplitude shown by significance probability mapping (SPM) when the waveform obtained by binaural stimulation was compared with the sum of the waves obtained by monaural stimulation. The topography of BI was different from that of the wave III and the wave IV/V complex. In contrast to previous reports by other workers, we found that BI mainly corresponded to the first half of the wave IV/V complex.
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Kato T, Shiraishi K, Imamura A, Kimura K, Morizono T, Soda T. Analysis of auditory brainstem response waveforms derived ipsilaterally and contralaterally to monaural stimulation. Auris Nasus Larynx 1995; 22:96-102. [PMID: 7487680 DOI: 10.1016/s0385-8146(12)80107-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The auditory brainstem responses (ABRs) obtained from 28 normal healthy adults were studied using the ipsilateral and contralateral recordings from the positions of vertex and each mastoid to monaural stimulation. Each wave of ABRs recorded by ipsilateral and contralateral derivations to stimulation site showed slightly significantly differences. Comparing the ipsilateral and contralateral data, the latencies of waves II and V showed a slightly small reduction in the ipsilateral recording, while these of waves III and IV showed a small increase. Next, the distributions of potentials and latencies of waves II to V were investigated from ABRs situating different electrodes in mid-coronal array of the scalp and non-cephalic reference electrode on the seventh cervical vertebra (CVII). The results of latencies showed the reverse relation to the data obtained from the ipsilateral and contralateral recordings using the reference electrodes on each mastoid. These facts suggest that the comparable differences of latencies in the bilaterally recorded ABRs are explained by the pseudo-phenomena of differential recordings, which the phase delayed or advanced potential propagated to each mastoid being reference electrode position.
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Abstract
Multiple myeloma is a malignant disease of the skeleton. Anatomically, any bone may ultimately come to be involved in a given case. In a literature review, no published series of temporal bone findings have been reported. In this study, oto-histopathologic changes associated with multiple myeloma are analyzed and reported in 15 temporal bones from 8 patients. The bone marrow of 13 temporal bones was involved by the tumor. Osteolysis was evident in 11 temporal bones. Serous otitis media (SOM) or purulent otitis media (POM) was seen in 13 ears with 12 showing mastoid effusions. Eight ears exhibited pathological changes in inner ears, including degeneration of the organ of Corti, atrophy of stria vascularis, decreased ganglion cells, and labyrinthine hydrops. The inner ear changes were most severe in 2 patients who had otologic symptoms. Infiltration of myeloma cells was not apparent in the middle ear mucosa or the inner ears.
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Abstract
In spite of the wealth of information on the clinical, histologic, and pathologic aspects of tympanosclerosis, the pathogenesis of tympanosclerosis is still unclear. In an attempt to understand the pathogenesis, 319 human temporal bones from 196 individuals with otitis media were studied. The extent and nature of tympanosclerosis and the characteristics of the otitis media associated with it were studied. Forty-five temporal bones from 35 individuals with otitis media were found to have tympanosclerosis, giving an incidence of 14.1%. It was seen most commonly in individuals over 40 years of age (86.7%). The male-to-female ratio was 1.6:1. The most common site of occurrence was the tympanic membrane (88.9%). Tympanosclerosis was seen more often in the anterior and posterior inferior quadrants of the tympanic membrane and that, too, in a central position. Tympanosclerosis was seen more commonly in temporal bones with irreversible inflammatory changes, and in this group, late plaques were more commonly seen than early or intermediate plaques. Audiometric charts failed to show any direct relationship between extent of tympanosclerosis and the severity of hearing loss. The only audiometric finding of any consequence was a mixed hearing loss in the presence of middle ear tympanosclerosis.
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Bhaya MH, Schachern P, Morizono T, Paparella MM. Potter's syndrome: a temporal bone histopathological study. THE JOURNAL OF OTOLARYNGOLOGY 1993; 22:195-199. [PMID: 8371331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Histopathological findings in seven temporal bones from four infants diagnosed as Potter's syndrome are described. The infants were labelled as Potter's syndrome after autopsy confirmed bilateral renal agenesis. Extrarenal manifestations included pulmonary hypoplasia and facial anomalies. The middle ear volume in infants with Potter's syndrome remained unchanged with age resulting in a significantly higher percentage of residual middle ear mesenchyme in these infants as compared to normal infants. Dehiscence of the facial nerve was seen in all the temporal bones studied. One ear showed the presence of eosinophilic effusion in the endolymphatic sac, an underdeveloped malleus and a wide facial nerve canal. The inner ear structures showed no significant anomalies except for the absence of the organ of Corti in the basal turn of the cochlea in one of the ears.
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Yagi T, Kurosaki S, Yamanobe S, Morizono T. Three-component analysis of caloric nystagmus in humans. ARCHIVES OF OTOLARYNGOLOGY--HEAD & NECK SURGERY 1992; 118:1077-80. [PMID: 1389059 DOI: 10.1001/archotol.1992.01880100069015] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Three-component analysis of caloric nystagmus, focusing on the horizontal, vertical, and torsional, using a computerized eye movement analysis system, was carried out in 10 normal human subjects. The caloric response was induced by cold stimulation to the right ear of the subjects in the supine and prone positions. In the supine position, the three components of nystagmus were toward the left (10 subjects), upward (eight subjects) or downward (two subjects), and clockwise (10 subjects). In the prone position, on the other hand, the three components were directed toward the right (10 subjects), downward (five subjects), upward (three subjects), and counterclockwise (10 subjects); there was no vertical direction in two subjects. These findings indicate that caloric stimulation activates the three semicircular canals simultaneously. Also the changes in the nystagmus direction in the supine and prone positions could be explained, at least partially, by the nonconvective component of caloric stimulation.
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Paparella MM, Morizono T, Matsunaga T. Kyoshiro Yamakawa, MD, and temporal bone histopathology of Meniere's patient reported in 1938. Commemoration of the centennial of his birth. ARCHIVES OF OTOLARYNGOLOGY--HEAD & NECK SURGERY 1992; 118:660-2. [PMID: 1637546 DOI: 10.1001/archotol.1992.01880060110023] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Tono T, Morizono T. Low-frequency modulation of compound action potential in experimental perilymphatic fistula and endolymphatic hydrops. Hear Res 1992; 60:27-33. [PMID: 1500374 DOI: 10.1016/0378-5955(92)90055-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We have tested the hypothesis that the cause of cochlear dysfunction associated with perilymphatic fistula (PLF) is closely related to endolymphatic hydrops (ELH). Using guinea pigs, we studied the tone-burst elicited compound action potential (CAP) and its modulation as caused by a 50 Hz biasing tone in experimental PLF. We compared these results with those of experimental ELH. Following perilymph aspiration through the perforated round window membrane, mild but significant elevations of CAP thresholds at tested frequencies were found. A reduction in the amplitude of cochlear microphonics (CM) for a 50 Hz sine wave appeared to correlate with these CAP threshold changes. However, there were no significant changes in the modulation effect of the 50 Hz biasing tone on the CAP elicited by an 8 kHz tone burst. This finding differed from that in ears with experimental ELH, in which significant reductions of both 50 Hz CM and the degree of CAP modulation were consistently observed. We concluded that it is unlikely that the underlying mechanisms of a modification to the low frequency response of the base of the cochlea following perilymph aspiration is linked to that of experimental ELH.
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Lundman L, Santi PA, Morizono T, Harada T, Juhn SK, Bagger-Sjöbäck D. Inner ear damage and passage through the round window membrane of Pseudomonas aeruginosa exotoxin A in a chinchilla model. Ann Otol Rhinol Laryngol 1992; 101:437-44. [PMID: 1570939 DOI: 10.1177/000348949210100511] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
By the use of computer-assisted morphometric analysis of the organ of Corti and/or measurements of action potential threshold changes, inner ear changes in chinchillas were evaluated 4 weeks after application on the round window membrane of a Pseudomonas aeruginosa exotoxin A solution. Severe inner ear damage was detected after application of 50 ng (5 microL at a concentration of 10 micrograms/mL) exotoxin A, whereas application of 5 ng exotoxin did not cause measurable inner ear damage. Perilymph concentrations of exotoxin A were measured with an enzyme-linked immunosorbent assay 1.5 to 19 hours after 50 ng, 0.5 micrograms, or 5 micrograms of exotoxin A was applied on the round window membrane. Only the highest concentration produced measurable levels of exotoxin in the inner ear fluids. It is concluded that exotoxin A present on the round window membrane of the chinchilla has the ability to penetrate into the inner ear and cause irreversible inner ear changes.
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Ikeda K, Morizono T, Juhn SK. Cochleotoxicity of otic drops in the chinchilla: comparative study of Bestron and Cortisporin. THE AMERICAN JOURNAL OF OTOLOGY 1991; 12:429-34. [PMID: 1805633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Bestron, a new otic preparation containing cefmenoxime, was applied to the round window membrane of the chinchilla and the long-term cochleotoxicity was evaluated by means of electrocochleography. The thresholds of the compound action potential (CAP) in all frequency areas tested ranged within normal values. The input-output and -latency relationships of the CAP resulted in no significant deterioration of hearing. However, identical treatment with Cortisporin resulted in elevated CAP threshold in the high frequency area and deterioration of the input-output and -latency of the CAP. These findings indicate that Bestron is noncochleotoxic as compared with Cortisporin and therefore may be used safely in the treatment of infected ears.
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Morizono T, Tono T. Middle ear inflammatory mediators and cochlear function. Otolaryngol Clin North Am 1991; 24:835-43. [PMID: 1870877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Sensorineural hearing loss (SNHL) has been documented in patients with otitis media. Despite a number of clinical and pathologic works dealing with this common problem, animal studies searching for possible relationships between the middle ear inflammation and cochlear function remain insufficient. Bacterial inoculation and ototoxins and inflammatory products in the middle ear cavity cause SNHL in rodents. Human serum albumin placed in the middle ear cavity in chinchillas also produces SNHL, owing to the effects of nonspecific inflammation in the middle ear cavity. Most of the middle ear inflammatory mediators enter the inner ear through the round window route, and alteration of the permeability of the round window membrane plays an important role in causing cochlear dysfunction. Although an immunologic response in the middle ear plays an important role in otitis media, the immunologic response in the inner ear as it relates to middle ear inflammatory mediators requires further study.
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Abstract
To investigate the influence of the cervical input to the equilibrium, the effect of neck vibratory stimulation on body sway was analyzed in 49 normal human subjects. Body perturbations during standing posture were recorded by a force platform with or without vibratory stimulus on the upper cervical region, and analyzed by computer. During the neck vibratory stimulation, the center of gravity was shifted to the forward, and the amplitude of the body sway was increased especially along the front-rear axis. These results indicate that the proprioceptive inputs from the cervical receptors largely modifies the body equilibrium in normal subjects.
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Ikeda K, Morizono T. The ionic and electric environment in the endolymphatic sac of the chinchilla: relevance to the longitudinal flow. Hear Res 1991; 54:118-22. [PMID: 1917711 DOI: 10.1016/0378-5955(91)90141-u] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The ionic composition of the endolymph in the endolymphatic sac (ES) of the chinchilla was measured using double-barreled ion-selective micro-electrodes. The DC potential of the ES was 9.3 +/- 1.8 mV (N = 18). The K+, Na+, and Cl- concentrations of the ES were 13.3 +/- 4.7 mM (N = 6), 129.0 +/- 8.8 mM (N = 6), and 124.3 +/- 16.6 mM (N = 6), respectively. In light of the chemical potentials of the cochlear endolymph previously reported [Ikeda and Morizono (1989), Hear. Res., 39, 279-286] the pressure gradient of the endolymph between the cochlea and ES was calculated to be 71.5 mmHg at 38 degrees C. The contribution of the osmotic and hydrostatic pressure gradients of the endolymph to the longitudinal flow is discussed.
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Ikeda K, Morizono T. Effect of ototopic application of a corticosteroid preparation on cochlear function. Am J Otolaryngol 1991; 12:150-3. [PMID: 1681756 DOI: 10.1016/0196-0709(91)90145-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The ototoxicity of the corticosteroid triamcinolone diacetate was investigated using the compound action potential (CAP) of the auditory nerve as a parameter when the drug was applied to the middle ear cavity of the chinchilla. Comparison with the contralateral ear, instilled with Ringer's solution, demonstrated no significant difference in the threshold, amplitude, and latency of the CAP responses at the overall frequencies tested. In addition, the side difference of the CAP threshold in individual animals showed that this corticosteroid did not induce cochlear dysfunction in any case.
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Ikeda K, Morizono T. Ionic activities of the inner ear fluid and ionic permeabilities of the cochlear duct in endolymphatic hydrops of the guinea pig. Hear Res 1991; 51:185-92. [PMID: 2032956 DOI: 10.1016/0378-5955(91)90035-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Ionic activities (K+, Na+, and Cl-) of the perilymph and endolymph of the basal turn were measured using ion-selective microelectrodes in experimentally induced endolymphatic hydrops of the guinea pig. Three months following the obstruction of the endolymphatic duct and sac, the endocochlear potential (EP) of hydroptic ears was measured at 59.7 +/- 9.6 mV (N = 12) which was significantly lower than the EP of the contralateral control ears (84.4 +/- 2.8 mV, N = 12). A paired t-test (P greater than 0.05) showed no significant differences of ion concentrations of the inner ear fluid between the hydroptic and contralateral ears. Ion permeabilities of the cochlear duct following anoxia were calculated according to the Nernst-Planck equation. Comparing hydroptic and normal ears following anoxia, a statistically significant decrease was observed in the permeability coefficients for K+. Similarly, K+ conductance was significantly lower in the hydroptic ears than in the normal ears. Total conductance of the cochlear duct, defined as the sum of each ion conductance, was 0.560 siemens in the normal ears and 0.217 siemens in the hydroptic ears. On the basis of the Goldman-Hodgkin-Katz equation, preexisting negative EP in the normal state was calculated to be -24.5 mV in normal ears and -21.4 mV in hydroptic ears. Therefore, the positive component of the EP was 108.9 mV in normal ears and 81.1 mV in hydroptic ears. These findings suggest that the pathophysiology of hydrops involves changes in K+ permeability and the inhibition of the electrogenic transport processes.
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Yagi T, Yamanobe S, Morizono T, Taira S, Kurosaki S, Kamio T. Three components analysis of eye movements using computerized image recognition. ACTA OTO-LARYNGOLOGICA. SUPPLEMENTUM 1991; 481:460-2. [PMID: 1927441 DOI: 10.3109/00016489109131445] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Juhn SK, Ikeda K, Morizono T, Murphy M. Pathophysiology of inner ear fluid imbalance. ACTA OTO-LARYNGOLOGICA. SUPPLEMENTUM 1991; 485:9-14. [PMID: 1843177 DOI: 10.3109/00016489109128038] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Maintenance of homeostasis of inner ear fluids and biochemical integrity of inner ear tissue are essential for proper functioning of the auditory and vestibular end organs. Although various regulatory mechanisms exist in a different portion of the labyrinth, the inner ear is known to respond to systemic challenges. The association of Meniere's syndrome with an imbalance of inner ear fluid homeostasis has been hypothesized for the past century. Among many factors, the effects of hormonal imbalance on inner ear fluid composition and inner ear function have however scarcely been studied. The purpose of this study was to explore the relationship between the autonomic nervous system and inner ear function and possible mechanisms of functional disturbances in an experimental condition. An infusion of supraphysiologic amounts of epinephrine, a stress related hormone, resulted in an elevation of osmolality in serum and perilymph. Furthermore, the infusion of epinephrine resulted in elevation of threshold, prolongation of latency, and depression of amplitude in the compound action potential of the auditory nerve. These findings were most marked at high frequencies. We hypothesized that the epinephrine-induced hearing loss was brought about by an increase in perilymphatic osmolality, as well as by the ionic imbalance caused by the osmotic gradient. Since emotional stress has been implicated as a mechanism of inducing a Meniere's attack, evaluation of the relationship between the autonomic system and cochlear function may contribute to the understanding of possible mechanisms of inner ear dysfunction caused by hormonal imbalances.
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Ikeda K, Morizono T, Takasaka T. Otic preparations altered permeability and thickness of the round window membrane of the chinchilla. ORL J Otorhinolaryngol Relat Spec 1991; 53:91-3. [PMID: 2011381 DOI: 10.1159/000276195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The effects of topical otic preparations (Cortisporin, Coly-Mycin, Aristocort, and Bestron) upon the permeability of the round window membrane (RWM) in chinchillas were investigated. Using K(+)-selective microelectrodes, the concentration of tetraethylammonium (TEA) ions was measured. Changes in the thickness of the RWM were measured using light microscopy. The RWM permeability was reduced significantly in Cortisporin- and Coly-Mycin-treated ears. Moreover, these two drugs resulted in a marked thickening of the RWM. In contrast, Aristocort or Bestron resulted in no alteration of the RWM permeability.
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Morizono T. Toxicity of ototopical drugs: animal modeling. THE ANNALS OF OTOLOGY, RHINOLOGY & LARYNGOLOGY. SUPPLEMENT 1990; 148:42-5. [PMID: 2112363 DOI: 10.1177/00034894900990s612] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
It is important to be aware of the potential ototoxicity of any drug, vehicle, or antiseptic that is used in the middle ear. Frequently used ear drops (Cortisporin otic suspension, Coly-Mycin S Otic, and VoSoL otic solution) were studied for their ototoxicity. Compound action potentials were measured before and at 1, 2, and 24 hours following drug application on the round window membranes of chinchillas. Each drug was applied for 10 minutes and then was removed by rinsing. The sound pressure in decibels sound pressure level that produced a compound action potential amplitude of 10 microV was defined as the threshold. The change in threshold was interpreted as hearing loss. On the basis of the short-term results at 24 hours following drug application, the ototoxicity of Coly-Mycin was calculated to be twice that of Cortisporin, and the ototoxicity of VoSoL four times that of Cortisporin.
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Ikeda K, Morizono T. Round window membrane permeability during experimental purulent otitis media: altered Cortisporin ototoxicity. THE ANNALS OF OTOLOGY, RHINOLOGY & LARYNGOLOGY. SUPPLEMENT 1990; 148:46-8. [PMID: 2161637 DOI: 10.1177/00034894900990s613] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Round window membrane (RWM) permeability is the most critical factor influencing cochlear function following otitis media. Because otic drops are frequently used during purulent otitis media (POM), we investigated RWM permeability and ototoxicity of Cortisporin otic suspension after inducing experimental POM. Unilateral POM was induced in eight chinchillas by inoculating type 7F Streptococcus pneumoniae into the right ears. Left ears were inoculated with phosphate-buffered saline (control). When POM resolved, the animals were divided into two groups. The round window niches of group 1 were covered with Cortisporin otic suspension. Compound action potentials were measured before and after drug application. The RWM permeability was measured in group 2 by use of tetraethylammonium (TEA) ions as tracers, and the arrival time of TEA and the slope of the potassium-selective microelectrode response were measured. Animals with otitis media exhibited less susceptibility to ototoxicity of Cortisporin otic suspension and reduced RWM permeability to the medium-sized molecule TEA.
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Yamanobe S, Taira S, Morizono T, Yagi T, Kamio T. Eye movement analysis system using computerized image recognition. ARCHIVES OF OTOLARYNGOLOGY--HEAD & NECK SURGERY 1990; 116:338-41. [PMID: 2306353 DOI: 10.1001/archotol.1990.01870030102018] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A new technique for an eye movement analysis system utilizing infrared video recording and a computerized image recognition method is presented. The system consists of an infrared lighting apparatus, a very small infrared video charge-coupled device camera, a video tape recorder, an analogue-digital converter, and microcomputers. This system makes it possible to simultaneously analyze the slow-phase velocity quantitatively not only of the horizontal and vertical but also of the rotatory components of the energy-induced nystagmus. The maximum slow-phase velocity of the rotatory component of energy-induced nystagmus was found to be 4.1 degrees per second on an average in this study.
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