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We investigated the localization of periostin in middle ear specimens from patients with eosinophilic otitis media (EOM) and from a newly constructed animal model for EOM. Periostin-positive immunostaining was observed in the middle ear sections obtained from the EOM patients. Immunoreactivity for periostin was also seen in the animal model. These results suggest that periostin plays an important role in subepithelial fibrosis in the middle ear in EOM.The purpose of the present study was to investigate the role of periostin in the middle ear of EOM patients and an animal model.Histological and immunohistochemical analyses for periostin were carried out in the middle ear specimens of six EOM patients with/without asthma. An animal model of EOM was constructed by intraperitoneal and topical sensitization with ovalbumin (OVA). Histological and immunocytochemical analyses for periostin were also performed in this model.Immunoreactivities for periostin were observed in the basement membrane and extracellular matrix of the middle ear sections obtained from all EOM patients with/without asthma. In the animal model, eosinophil infiltration and middle ear mucosa thickness were observed. Moreover, periostin-positive immunostaining was shown in the extracellular matrix of the middle ear mucosa on the side topically boosted by OVA.

Inflammatory pseudotumours in the maxillary sinus may present as malignant tumours and manifest locally aggressive features characteristic of such tumours. Despite their locally destructive features, they pursue a benign course after local excision.Inflammatory pseudotumour (plasma cell granuloma) is an uncommon non-neoplastic lesion comprising a proliferation of spindle myofibroblasts and chronic inflammatory cells. Despite its benign histopathological nature, it may exhibit aggressive behaviour that is yet to be characterized in the head and neck area.We present the cases of two adult patients with inflammatory pseudotumour arising from the maxillary sinus. Immunohistochemistry and polymerase chain reaction for immunoglobulin from tissue sections were performed to confirm the polyclonality of the infiltrating plasma cells.CT and MRI disclosed expansive soft masses eroding surrounding soft and bony tissues. Histopathologically, the lesions were unencapsulated and composed of numerous plasma cells, histiocytes and spindle cells with minimal nuclear pleomorphism.

Gamma-aminobutyric acid (GABA) is thought to be the major inhibitory neurotransmitter in the central nervous system. Although it is distributed in the olivo-cochlear bundles, which constitute the mammalian cochlear efferent system, its function in the cochlea is still obscure. In this study, we investigated the localization of GABAa receptor subunits (alpha1-6, beta1-3, gamma) in the rat cochlea in order to determine the role of GABA in the cochlea. Most spiral ganglion cells were intensely immunolabeled with all the anti-GABAa receptor subunit antibodies. In the organ of Corti, punctate immunoreactivities were observed in inner hair cell regions corresponding to the distribution of GABA. These data suggest that GABAa receptor was present in afferent nerve terminals in inner hair cell regions, and that GABA regulated afferent nerve transmission contacting efferent nerve endings by means of the axo-dendritic synapse function.

The present study was conducted to elucidate species differences in the distribution of neuroactive substances, including substance P (SP), calcitonin gene-related peptide (CGRP) and gamma-aminobutyric acid (GABA), in the vestibular periphery of various animals (chicken, pigeon, rat, guinea pig and squirrel monkey). SP-like immunoreactivity was found in a subset of the primary vestibular afferents with no marked species differences in the staining pattern. In contrast, the localization of CGRP- and GABA-like immunoreactivities in the efferent nerve fibers varied according to species. This difference in the distribution pattern of neuroactive substances, found in the efferent system, may indicate that each species has a chemically (and probably functionally) distinct efferent system which is related to its specific environment and/or evolution.

To investigate the vestibular function in patients with bilateral progressive sensorineural hearing loss, we examined 5 cases using electronystagmography. Cases 1, 2 and 3 were adult type, and Cases 4 and 5 juvenile type. All patients had dizzy spells in the early stage of the disease, and showed spontaneous nystagmus. Bilateral reduction of caloric response and very low vestibulo-ocular reflex (VOR) gain on rotation testing were observed in Cases 1, 2 and 3. Case 4 showed right canal paresis upon the caloric test and left directional preponderance upon the rotation test. Case 5 showed good responses to both tests. Optokinetic afternystagmus (OKAN) in Cases 2, 3 and 5 was not brisk, and Cases 1 and 2 showed directional preponderance of OKAN. OKAN was useful for detecting directional preponderance. We believe there are two types of this disease which correlate with vestibular function. One type is associated with high grade vestibular dysfunction while, in the other, vestibular function is reasonably good.

The effect of diuretics on endolymphatic hydrops, which was produced by obliteration of the endolymphatic duct and sac in guinea pigs, was determined by statistical analysis of volumetric changes in the scala media. When acetazolamide was administered orally at 159 to 434 mg/kg per day for a period of 30 days, endolymphatic hydrops did not reach the extent of distension shown in animal ears without drug treatment. No difference was seen in animals with one month of drug treatment followed by three additional months without treatment. This result suggests that acetazolamide has the effect of reducing endolymphatic hydrops only during the period of drug administration. On the other hand, there appeared to be no effect, statistically, on hydrops in animals which were treated with chlorthalidone 72 to 182 mg/kg every other day for one month with survival times varying from one to four months. The effect of this drug favorably reported for the treatment of Meniere's disease symptoms is not demonstrated on endolymphatic hydrops, but rather is likely to involve other mechanisms. There was no essential difference in the extent of cochlear sensory and neural atrophy in the inner ears of animals with or without these drug treatments.