Radiotherapy for a rare phosphaturic mesenchymal tumor in the middle ear presenting with oncogenic osteomalacia: A case report.

RATIONALE: Phosphaturic mesenchymal tumor (PMT) is a rare neoplasm causing oncogenic osteomalacia. Surgery remains the definitive treatment for PMT, and radiotherapy is seldom employed. However, surgery for PMT involving the head and neck is often difficult due to the local invasion and complicated anatomy. We report the first case of PMT, which was successfully treated with the combination of radiotherapy and supplementation of activated vitamin D. PATIENT CONCERNS: A 55-year-old woman suffered from pain in the hip and bilateral femur. Serum phosphate and calcium decreased to abnormal levels. Serum alkaline phosphatase and fibroblast growth factor 23 increased to abnormal levels. The hearing loss of the right ear had continued and a middle ear tumor was revealed. DIAGNOSES: Subsequent biopsy provided the diagnosis of PMT that caused oncogenic osteomalacia. These clinical and pathological characteristics were consistent with and provided the final diagnosis of benign PMT. INTERVENTIONS: Surgery of the PMT was difficult and the patient underwent radiotherapy. The prescribed dose was 36 Gy in 10 fractions. Simultaneously, the patient started supplementation of 1,25-dihydroxyvitamin D3 (1-2 µg/day) and continued for 2 years. OUTCOMES: Near-complete resolution of the symptoms was achieved and abnormal laboratory values recovered. At 5 years of follow-up, the irradiated tumor showed no regrowth. Severe hearing loss of the right ear was not observed. LESSONS: Radiotherapy was effective for the PMT and could be an important treatment option for inoperable cases.

Brainstem auditory evoked responses in 37 dogs with otitis media before and after topical therapy.

OBJECTIVES: The objective of this study was to determine whether intra-aural administration of aqueous solutions of marbofloxacin, gentamicin, tobramycin and ticarcillin (used off-licence) was associated with changes in hearing as measured by brainstem auditory evoked responses. MATERIALS AND METHODS: Dogs diagnosed with otitis media (n=37) underwent brainstem auditory evoked response testing and then were treated for their ear disease. First, the external ear canal and middle ear were flushed with sterile saline followed by EDTA tris with 0·15% chlorhexidine. Then, a combination of aqueous antibiotic mixed with an aqueous solution of EDTA tris was instilled into the middle ear. Follow-up examinations were undertaken for each dog, and treatment was continued until there were no detected infectious organisms or inflammatory infiltrate. Brainstem auditory evoked response testing was repeated after resolution of the infection and discontinuation of therapy. RESULTS: Brainstem auditory evoked responses in dogs treated with aqueous solutions of marbofloxacin or gentamicin remained unchanged or improved after therapy of otitis media but were impaired in dogs treated with ticarcillin or tobramycin. CLINICAL SIGNIFICANCE: If off-licence use of topical antibiotics is deemed necessary in cases of otitis media, aqueous solutions of marbofloxacin and gentamicin appear to be less ototoxic than aqueous solutions of ticarcillin or tobramycin.

Weak Middle-Ear-Muscle Reflex in Humans with Noise-Induced Tinnitus and Normal Hearing May Reflect Cochlear Synaptopathy.

Chronic tinnitus is a prevalent hearing disorder, and yet no successful treatments or objective diagnostic tests are currently available. The aim of this study was to investigate the relationship between the presence of tinnitus and the strength of the middle-ear-muscle reflex (MEMR) in humans with normal and near-normal hearing. Clicks were used as test stimuli to obtain a wideband measure of the effect of reflex activation on ear-canal sound pressure. The reflex was elicited using a contralateral broadband noise. The results show that the reflex strength is significantly reduced in individuals with noise-induced continuous tinnitus and normal or near-normal audiometric thresholds compared with no-tinnitus controls. Due to a shallower growth of the reflex strength in the tinnitus group, the difference between the two groups increased with increasing elicitor level. No significant difference in the effect of tinnitus on the strength of the middle-ear muscle reflex was found between males and females. The weaker reflex could not be accounted for by differences in audiometric hearing thresholds between the tinnitus and control groups. Similarity between our findings in humans and the findings of a reduced middle-ear muscle reflex in noise-exposed animals suggests that noise-induced tinnitus in individuals with clinically normal hearing may be a consequence of cochlear synaptopathy, a loss of synaptic connections between inner hair cells (IHCs) in the cochlea and auditory-nerve (AN) fibers that has been termed hidden hearing loss.

Antifibrotic effect of dexamethasone/alginate-coated silicone sheet in the abraded middle ear mucosa.

Silicone sheet is a material which is commonly used in middle ear surgery to prevent the formation of adhesions between the tympanic membrane and the medial bony wall of the middle ear cavity. However, silicone sheet can induce a tight and hard fibrous capsule in the region of the stapes, and this is particularly common in cases of eustachian tube dysfunction. As a result of the fibrous encapsulation around the silicone sheet, postoperative aeration of the stapes can be interrupted causing poor hearing gain. In this study, we performed an in vitro and in vivo evaluation of the antifibrotic effects of a dexamethasone and alginate (Dx/alginate) coating on silicone sheet. The Dx/alginate-coated silicone sheets were fabricated using a plasma-treatment and coating method. The Dx/alginate-coated silicone sheets effectively limited in vitro fibroblast attachment and proliferation due to the controlled release of Dx, which can be modified by manipulation of the alginate coating. For the in-vivo evaluation, guinea pigs (albino, male, weighing 250g) were divided into two groups, with the control group (n=5) implanted with silicone sheet and the test group (n=5) receiving Dx/alginate-coated silicone sheet. Animals were sacrificed 3 weeks after implantation, and histological analysis was performed using hematoxylin and eosin (H&E) and immunohistochemical staining techniques. Dx/alginate-coated silicone sheets showed marked inhibition of fibrosis in both the in vitro and in vivo studies. Silicone sheet that incorporates a Dx/alginate coating can release Dx and inhibit fibrosis in the middle ear. This material could be utilized in middle ear surgery as a means of preserving proper aeration and hearing gain following ossiculoplasty.

Mucosal trauma induced apoptosis in guinea pig middle ear: comparision of hemostatic agents.

OBJECTIVE: The aim of this study is to compare the effects of the absorbable gelatin sponge (AGS), microporous polysaccharide hemospheres (MPH), and Ankaferd on wound healing after middle ear trauma and to evaluate their ototoxicity in an experimental guinea pig model. METHODS: Middle ear mucosal trauma was created in 21 healthy adult guinea pigs. MPH, Ankaferd, and AGS were applied into the right tympanic bulla of the guinea pigs (7 ears for each treatment modality). The left ears of the seven animals were used as the sham group. At the fourth postoperative week (28-30 days), the guinea pigs were decapitated. Apoptosis was investigated, and the expression of Bcl-xl, Apaf, p53, cytochrome 3, and caspase 3 were evaluated. RESULTS: The Ankaferd and AGS groups demonstrated significantly lower epithelial thickness, inflammation, and capillary dilatation than did the control group (p<0.001, <0.001, /0.001, <0.001/, 0.005, and 0.005, respectively). A statistically significant decrease in Bcl-xl staining was observed in the middle ears of animals treated with MPH (p=0.003). There was significantly higher caspase 3 expression in the Ankaferd and AGS groups than in the control group (p<0.001 and p=0.002, respectively). CONCLUSION: Light microscopy indicates that Ankaferd and AGS create less inflammation and increased caspase expression, which seems to induce inflammatory cell apoptosis. Ankaferd seems to be a promising hemostatic agent in otology.

Electromyographic response of facial nerve stimulation under different levels of neuromuscular blockade during middle-ear surgery.

OBJECTIVE: To investigate facial nerve monitoring in patients receiving the partial nondepolarizing neuromuscular blocking agents (NMBAs), remifentanil and propofol. METHODS: Patients with normal facial function and advanced middle-ear disease were enrolled. For total intravenous anaesthesia (TIVA), propofol and remifentanil were infused as induction/maintenance anaesthesia. Stimulation thresholds and amplitudes were recorded at each train-of-four (TOF) nerve stimulation level. Time differences between start of TOF and electromyographic (EMG) amplitude decreases (Ti), and between complete recovery of TOF and EMG amplitudes (Tr), were calculated. RESULTS: Fifteen patients were enrolled. Mean ± SD Ti was 3.4 ± 1.28 min; Tr was 18.7 ± 4.41 min. Amplitude of stimulation was apparent mostly at TOF level 1. In most cases, no or a weak response (<100 µV) was observed at TOF 0. Mean ± SD threshold of electrical stimulation was 0.31 ± 0.10 mA at TOF 1. At TOF > 2, all cases showed EMG response on electrical stimulation. CONCLUSIONS: Induction of TIVA using propofol and remifentanil provided reliable conditions for delicate microsurgery. Minimal NMBA use, considered as producing TOF levels >1, was sufficient for facial nerve monitoring in neuro-otological surgery.

Perspective of functional magnetic resonance imaging in middle ear research.

Functional magnetic resonance imaging (MRI) studies have frequently been applied to study sensory system such as vision, language, and cognition, but have proceeded at a considerably slower speed in investigating middle ear and central auditory processing. This is due to several factors, including the intrinsic anatomy of the middle ear system and inherent acoustic noise during acquisition of MRI data. However, accumulating evidences have demonstrated that clarification of some fundamental neural underpinnings of audition associated with middle ear mechanics can be achieved using functional MRI methods. This mini review attempted to take a narrow snapshot of the currently available functional MRI procedures and gave examples of what may be learned about hearing from their application. It is hoped that with these technical advancements, many new high impact applications in audition would follow. In particular, because the fMRI can be used in humans and in animals, fMRI may represent a unique tool that should promote translational research by enabling parallel analyses of physiological and pathological processes in the human and animal auditory system. This article is part of a special issue entitled "MEMRO 2012".

Clinical use of vestibular evoked myogenic potentials in the evaluation of patients with air-bone gaps.

OBJECTIVE: To determine the value of vestibular evoked myogenic potential (VEMP) test in clinical evaluation of air-bone gaps. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: A total of 120 patients underwent VEMP testing during clinical investigation of significant air-bone gaps in their audiograms. INTERVENTION(S): Otologic examination and surgeries, high-resolution computerized tomography (CT), air and bone audiometry, tympanometry, acoustic reflex, and VEMP test. MAIN OUTCOME MEASURE(S): Imaging studies demonstrating structural anomalies in the temporal bone. Audiologic outcomes of air-bone gaps and VEMP thresholds. Surgical findings confirming imaging results. RESULTS: Middle ear pathologies, such as otosclerosis and chronic otitis media, were identified in 50 patients, and all of them had absent VEMP responses elicited by air-conduction stimuli. Moreover, 13 of them had successful middle ear surgeries with closures of the air-bone gaps. Abnormally low VEMP thresholds were found in 71 of 73 ears with inner ear anomalies, such as semicircular canal dehiscence and enlarged vestibular aqueduct. Seven patients with superior semicircular canal dehiscence underwent plugging procedure via middle fossa approach, and VEMP thresholds became normalized after the surgery in 3 of them. VEMP test failed to provide accurate diagnosis in only 3 cases. CONCLUSION: Air-bone gaps may be a result of various otologic pathologies, and the VEMP test is useful during clinical evaluation, better than tympanometry and acoustic reflexes. To avoid unnecessary middle ear surgery for air-bone gaps with unknown or unsure cause, VEMP test should be used in the differential diagnosis before an expensive imaging study.

Pathological features in the LmnaDhe/+ mutant mouse provide a novel model of human otitis media and laminopathies.

Genetic predisposition is recognized as an important pathogenetic factor in otitis media (OM) and associated diseases. Mutant Lmna mice heterozygous for the disheveled hair and ears allele (Lmna(Dhe/+)) exhibit early-onset, profound hearing deficits and other pathological features mimicking human laminopathy associated with the LMNA mutation. We assessed the effects of the Lmna(Dhe/+) mutation on development of OM and pathological abnormalities characteristic of laminopathy. Malformation and abnormal positioning of the eustachian tube, accompanied by OM, were observed in all of the Lmna(Dhe/+) mice (100% penetrance) as early as postnatal day P12. Scanning electronic microscopy revealed ultrastructural damage to the cilia in middle ears that exhibited OM. Hearing assessment revealed significant hearing loss, paralleling that in human OM. Expression of NF-κB, TNF-α, and TGF-ß, which correlated with inflammation and/or bony development, was up-regulated in the ears or in the peritoneal macrophages of Lmna(Dhe/+) mice. Rugous, disintegrative, and enlarged nuclear morphology of peritoneal macrophages and hyperphosphatemia were found in Lmna(Dhe/+) mutant mice. Taken together, these features resemble the pathology of human laminopathies, possibly revealing some profound pathology, beyond OM, associated with the mutation. The Lmna(Dhe/+) mutant mouse provides a novel model of human OM and laminopathy.

Myringoplasty in simple chronic otitis media: critical analysis of long-term results in a 1,000-adult patient series.

OBJECTIVES: Investigate the recurrence of chronic otitis media after primary and revision myringoplasty, compare long-term anatomic and audiologic results of underlay and overlay myringoplasty, and examine the prognostic factors. STUDY DESIGN: Retrospective study. PATIENTS: Approximately 1,040 adult patients with chronic simple otitis media undergoing a myringoplasty (overlay and underlay) by different surgeons at a single institution (ENT Department of Bergamo Ospedali Riuniti) between May 1999 and March 2009. METHODS: The cumulative recurrence rate of chronic otitis media during 10-year follow-up period was calculated using a Kaplan-Meier survival analysis. A multivariate analysis was used to evaluate different prognostic factors based on long-term outcome in myringoplasty. RESULTS: The overall 10-year graft success rate was 78% in 1,040 patients. The 10-year recurrence rate of chronic otitis media was 15% in overlay myringoplasty and 26% using the underlay technique (p < 0.05). In revision myringoplasty, the overlay technique showed a better success rate than underlay (p < 0.05). Significant recovery was observed in the air conduction thresholds and air-bone gaps in both groups with no statistical difference between techniques (p = 0.1). Multivariate analysis demonstrated that the underlay myringoplasty technique, a pathologic contralateral ear and an anterior or subtotal perforation, using a perichondrial graft or age of surgery younger than 40 years were statistically significant (p < 0.01) factors that negatively influenced the myringoplasty outcomes. CONCLUSION: More successful outcomes in primary and revision surgery for chronic otitis media occurred using overlay myringoplasty, although there were more minor postoperative complications. Both clinical and technical variables affected the success rate of myringoplasty.

Multifield coupled finite element analysis for sound transmission in otitis media with effusion.

In this paper, a newly constructed three-dimensional finite element (FE) model of the human ear based on histological sections of a left ear temporal bone is reported. The otitis media with effusion was simulated in the model with variable fluid levels in the middle ear. The interfaces among the air, structure, and fluid in the ear canal and middle ear cavity were identified and the acoustic-structure-fluid coupled FE analysis was conducted when the middle ear fluid level was varied from zero to full fill of the cavity. The results show how the displacements of the tympanic membrane and stapes footplate or the middle ear transfer function is affected by fluid in the cavity across the auditory frequencies. Comparison of model results with measured data in temporal bones indicates that this model has the capability to extend FE analysis into pathological ears such as otitis media with visualized fluid-air interfaces inside the middle ear structures.

[The outcome of treatments for carcinoma of the external auditory canal]. / Résultats des traitements des tumeurs malignes du conduit auditif externe.

OBJECTIVE: A retrospective analysis of management and survival of patients treated for temporal bone carcinoma. PATIENTS AND METHODS: Thirty patients underwent treatment for carcinoma of the temporal bone. Twenty-five squamous cell carcinomas, 1 melanoma, 2 basocellular carcinomas and 2 adenoid cystic carcinomas were treated. Thirteen patients were treated before for the same disease. RESULTS: Staging revealed 12 T1 and T2, 6 T3 and 12 T4 tumours. The mean follow up was 5 years (2-276 months). The Kaplan Meier survival curves showed survival rates at 2 years of 82%, 67% and 32%, and at 5 years of 82%, 67% and 17%, respectively for the stages T1 or T2, T3 and T4. At the end of follow up at 9 years the survival rates were 66%, 66% and 17% for the stages T1 or T2, T3 and T4 respectively. Overall stages a complete remission was found in 65% and 23%, and deceased was 35% and 77%, respectively for the primary treatment group and the salvage surgery group. CONCLUSION: Long-term prognosis of the carcinoma of the external auditory canal mainly depends on the stage and primary treatment. Surgery (lateral temporal bone or subtotal temporal bone resection, both in combination with a neck dissection and a parotidectomy) and adjuvant radiotherapy is the treatment of choice for part of stage T1 and all T2 and T3 tumours. The improved survival (65%) of patients treated de novo compared with those treated with salvage surgery (23%) suggests that early referral and aggressive primary surgical treatment with postoperative radiotherapy offer the greatest chance of cure.

Otitis media in dairy calves: a retrospective study of 15 cases (1987 to 2002).

Epidemiological data, clinical signs, complementary examination findings, antimicrobial treatments, and outcome were reviewed in 15 calves diagnosed with otitis media at the Centre hospitalier universitaire vétérinaire de l'Université de Montréal between 1987 and 2002. Age at presentation ranged from 2 to 18 weeks. A purulent ear discharge and epiphora were seen in 8/12 and 6/15 cases, respectively. Neurological signs observed were head tilt (13), eyelid ptosis (7), paresis/paralysis of the pinna (8), ataxia (2), strabismus (2), and convulsions (1). Concurrent pneumonia was frequently diagnosed (n = 11). A Mycoplasma sp. was the principal pathogen isolated from ear discharge; 6 out of 6 samples submitted were positive for mycoplasma. Tympanic bullae radiographs were considered abnormal in 12 out of 13 cases. Cerebrospinal fluid analysis was considered abnormal in 2 out of 5 cases. The antibiotic most commonly used was enrofloxacin (n = 7). Average treatment duration was 19.6 days. Four out of 8 treated animals for which follow-up information was available completely recovered. These results suggest that M. bovis is a major pathogen of otitis media in dairy calves and effective antimicrobial therapy should be of long duration.

Can low frequency sound stimulation during posturography help diagnosing possible perilymphatic fistula in patients with sensorineural hearing loss and/or vertigo?

Perilymphatic fistula (PLF) is often difficult to diagnose because of the similar symptomatology, such as vertigo, tinnitus and hearing loss, which is found in several inner ear diseases. We attempted to correlate a positive result of low frequency sound (LFS) stimulation tests in posturography with the presence or absence of a PLF confirmed by transtympanic endoscopy in 209 patients with various inner ear diseases (Meniere's disease ( n=128), vestibulopathy ( n=41), cochleopathy ( n=28) and sudden deafness ( n=12). LFS provoked unsteadiness in posturography without PLF in 24 patients with Meniere's disease, in 5 patients with vestibulopathy, in 3 patients with cochleopathy and in 2 patients with sudden deafness. In one patient, tympanoscopy revealed fistula in the round window membrane that was covered with a fibrinous layer. In four cases there was abnormal light reflex in the round window but without PLF. In eight cases, Hennebert's sign was present with nystagmus, without PLF. We conclude that pathological responses to the LFS test in posturography can also be encountered in other inner ear diseases without PLF.

Nitric oxide contributes to control of effusion in experimental otitis media.

OBJECTIVES/HYPOTHESIS: Nitric oxide (NO) is a small, short-lived free radical involved in cellular signaling and known to play a role in inflammation. It is generated on demand by the enzyme nitric oxide synthase (NOS) on arginine. We have previously found that mRNA encoding NOS is produced in the middle ear during otitis media. The role of NO was therefore explored in an experimental model of immune-mediated otitis media. STUDY DESIGN AND METHODS: Guinea pigs were systemically immunized and later challenged in the middle ear with the same antigen. One ear of each animal was challenged with antigen alone. In the opposite ear, antigen was combined with a potent inhibitor of NOS, N(G)-amino-L-arginine (L-NAA). After survival for 24, 48, or 72 hours, the middle ears were evaluated for otitis media. RESULTS: Inhibition of NOS resulted in significantly increased middle ear effusion at all three time periods. This increase was blocked by the addition of excess 1-arginine, which bypasses the inhibitory effects of L-NAA. The infiltration of cells into the middle ear lumen and the hyperplasia of the middle ear mucosa were unaffected by L-NAA administration. CONCLUSIONS: The results suggest that NO is involved in regulating the permeability of the middle ear vascular, the transudation of serum into the middle ear mucosa, and/or the movement of extracellular fluid across the middle ear mucosal epithelium.

[Combined drug therapy in patients with chronic otitis media and mucositis]. / Kompleksnaia konservativnaia terapiia bol'nykh khronicheskim srednim otitom s mukozitom.

The data of the authors own studies using conservative therapy in patients with chronic otitis media (COM) and mucositis are presented. The efficiency of treatment of these patients is shown depending on the method of treatment (the highest efficiency being noted in the main group of patients in whom the altered middle ear mucosa was concurrently exposed to autoserum (AS) and magnetic laser therapy (MLT). The efficiency of this or that conservative treatment was found to be related to the magnitude of altered middle ear mucosal changes: the more marked the signs of mucositis are, the more difficult it is to achieve a positive result. The results of treatment were assessed visually (under an operating microscope), bacteriologically, cytologically, and crystallographically. There was a correlation between the visual assessment of obtained treatment results and crystallographic findings. The high efficiency of the proposed treatment in patients with COM and mucositis is determined by the concurrent combined AS and MLT exposure of the entire thickness of the changed mucosa and by the stimulating action of MLT on AS. This conservative therapy can pretend to be the method of choice in treating patients with COM and mucositis.

Effects of capsaicin pre-treatment in experimentally-induced secretory otitis media.

Neurogenic inflammation may play a role in the aetiology of secretory otitis media (SOM). The strongest candidate that initiates the characteristic symptoms of neurogenic inflammation is supposed to be substance P. Capsaicin is a specific antagonist of substance P. The effects of capsaicin on middle ear mucosa have not been studied yet. In an attempt to investigate the effect of pre-treatment with capsaicin on the development of SOM an experimental study was performed. Fourteen Wistar rats were divided into two groups. Seven rats were pre-treated with capsaicin (Group 1) and the others were administered isotonic saline solution (Group 2). Seven days after the third injection rats were operated on and the right tympanal orifice of the Eustachian tube was obstructed. Animals were sacrificed seven days after the operation. Their bullas were excised bilaterally and were studied by light microscopic technique. In Group 1 there was no effusion except for one case. The subepithelial layer was thickened by fibroblast proliferation. Capillary proliferation and some glandular atrophy were observed. In Group 2 the middle ear lumens were filled with effusion. Oedema with dilatation in capillaries and medium-sized vessels of lamina propria was observed as a common feature of the group. Subepithelial fibrosis was found in one case. Capsaicin pre-treatment prevented the formation of effusion in the middle ear lumen in spite of tuba occlusion. The results of this preliminary study lead us to consider that an imbalance in the autonomic innervation of the mucosa of the middle ear may play a role in the aetiology of SOM as in vasomotor rhinitis, and capsaicin may be an alternative in the treatment.

The herbal medicine, sairei-to, prevents endotoxin-induced otitis media with effusion in the guinea pig.

With current pharmacotherapy, otitis media with effusion (OME) is often recurrent and even develops to become chronic. There is now considerable experimental and clinical evidence that the cilia in the tubotympanum play an important part in the prevention of OME. A herbal medicine, sairei-to, has been shown to stimulate the ciliary activity in vitro, and oral administration of the medicine also stimulated the ciliary activity in the tubotympanum rather than physiological states. This study was designed to investigate whether oral administration of sairei-to could prevent experimental OME in the guinea pig. A total of 120 guinea pigs were used. The control group was treated with intratympanic injection of 0.1 ml of physiologic saline solution. The saline-control group was treated with oral administration of physiologic saline solution for 14 successive days. The low-dosage group and the high-dosage group were treated with oral administration of 120 and 600 mg/kg of sairei-to for 14 successive days, respectively. The saline-control group, the low-dosage group and the high-dosage group were then treated with intratympanic injection of 0.1 ml of lipopolysaccharide solution (100 micrograms/ml) derived from Klebsiella pneumoniae. All 10 animals from the 4 groups were sacrificed 1, 3, and 7 days after the intratympanic injection, to examine ciliary activity, mucociliary clearance time, and mucosal pathology of the tubotympanum. The saline-control group exhibited middle ear effusions and pathologies similar to human OME. The incidence of middle ear effusions in the low-dosage and the high-dosage groups was somewhat reduced compared with the saline-control group. The ciliary activity in the tubotympanum was significantly reduced in the saline-control and low-dosage groups compared with the normal-control group. By contrast, the magnitude of reduction in ciliary activity was much smaller in the high-dosage group. The ciliary activity especially in the Eustachian tube and the middle ear close to the tympanic orifice at 3 and 7 days in the high-dosage group was not significantly different from that in the normal-control group. Mucociliary clearance time in the high-dosage group was not different from that in the normal-control group throughout the observation period. The groups treated with sairei-to, especially the high-dosage group, exhibited much milder pathological changes in the tubotympanum than did the saline-control group. In conclusion, clinical application of sairei-to could be an effective measure to prevent the occurrence of OME and also the recurrence of the disease, especially OME-prone individuals.

Morphological studies on middle ear barotrauma in guinea pigs.

Experimental middle ear barotrauma was studied morphologically. White guinea pigs were placed in an experimental hyperbaric chamber, and middle ear barotrauma was created by increasing the pressure in the hyperbaric chamber from 1 atmosphere absolute (ATA) to 2 ATA using pure oxygen, maintaining the pressure at 2 ATA for 10 minutes, then again reducing the pressure to 1 ATA. Selected experimental animals were decapitated immediately after, one day after, one week after, or weeks after pressure loading, and their middle ears were examined by a light microscope (LM), a scanning electron microscope (SEM) and a transmission electron microscope (TEM). Hemorrhaging in the tympanic cavity immediately after pressure exposure was apparent even macroscopically. LM also revealed evidence of submucous hemorrhage. Submucous edema was seen in the "one week after" cases. SEM showed a minor loss of cilia in some ciliated cells just after the experiment. In nonciliated cells, the terminal web was somewhat indistinct in the "one week after" cases. TEM also indicated a minor loss of cilia in some ciliated cells in "one day after" cases as well as apparent vacuoles within the cells. These findings suggest that although trauma during compression is more marked than during decompression, recovery from this damage progressed with time.

Acoustic input impedance of the stapes and cochlea in human temporal bones.

The acoustic input impedance of the stapes and cochlea ZSC represents the mechanical load driven by the tympanic membrane, malleus and incus. ZSC was calculated from broad-band measurements (20 Hz to 11 kHz) of stapes displacement made with an optical motion sensor and of sound pressure at the stapes head in a human temporal-bone preparation. Measurements were made in 12 fresh temporal bones with the round window insulated from the sound stimulus. Below 1 kHz, the magnitude of ZSC was approximately inversely proportional to frequency, and ZSC angle was between 0.10 and -0.20 periods. This behavior is consistent with a mixed stiffness and resistance. Between 1 and 4 kHz, ZSC was resistance-dominated with a magnitude between 40 and 100 mks acoustic G omega that was roughly independent of frequency, and its angle was between -0.12 and 0 periods. Between 4 and 7 kHz, the magnitude of ZSC was either constant or increased with frequency while ZSC angle was near 0. Between 7 and 8 kHz, both ZSC magnitude and angle decreased sharply with frequency, and both increased somewhat at higher frequencies. The input impedance of the cochlea ZC was estimated in one ear from ZSC measurements made before and after draining the inner ear fluids. ZC was stiffness-dominated below 100 HZ, and resistance-dominated from 100 Hz to 5 kHz. The frequency-dependent magnitude of ZSC in our bones is similar to those reported by other investigators in cadaver temporal bones (Nakamura et al., 1992; Kurokawa and Goode, 1995). Our ZSC measurements are qualitatively similar to theoretical predictions (Zwislocki, 1962; Kringlebotn, 1988), but are a factor of 3 greater in magnitude, implying that ZSC may be more resistive and stiffer than previously thought. We found inter-ear variations of a factor of 4 (12 dB), which may explain some of the clinically observed variations in size of the air bone gap in individuals with middle ear lesions or after middle-ear reconstructive surgery.