Long-term outcome of facial palsy in neuroborreliosis.

OBJECTIVES: The objectives of this study were to examine children with previous manifest neuroborreliosis and concommitant facial palsy to see whether there were any persisting symptoms and/or signs of persistent residual facial palsy. STUDY DESIGN: Open, controlled prospective study. SETTING: Tertiary referral center (University Hospital). PATIENTS: The study was conducted on twenty-four patients with clinically manifest neuroborreliosis and facial palsy 3 to 5 years prior to the investigation. MAIN OUTCOME MEASURES: Results of the clinical examination using the House-Brackmann scale were compared to results from two neuro-physiological examinations (qEMG and ENoG). RESULTS: Approximately one-half of the patients with reported subjective symptoms of residual facial palsy had signs of slight dysfunction in the clinical examination using the House-Brackmann scale. There was no correlation between the subjective feeling of facial dysfunction and presence of clinical signs. Likewise, about one-half of the subjective facial dysfunction group, as well as the control group, were found to demonstrate pathological values in their neurophysiological examinations using qEMG and ENoG. CONCLUSIONS: This study shows that the assumption is not true that all children who had neuroborreliosis with facial palsy will heal 100%. A small proportion of the children claim that several years after the infection, they have subjective symptoms of slight facial weakness on the affected side. Our study shows that some of these children, as well as some children without subjective symptoms of facial palsy, demonstrate a slight facial weakness when examined clinically. Likewise, signs of slight-to-moderate facial motor dysfunction were revealed in about half of the children with the two neurophysiological methods utilized in this study. It is interesting to note that there was no clear correlation between the presence of subjective symptoms, objective signs, and neurophysiological results.

Local administration of antioxidants to the inner ear. Kinetics and distribution(1).

Round window (r.w.) administration of drugs involves the delivery of medication directly into the inner ear via the r.w. membrane, avoiding a systemic effect of the therapy. Earlier experimental studies suggest that a number of antioxidants and scavengers hold promise for ameliorating the tissue damaging capacity of reactive oxygen species in some acquired cochlear disorders. D-Methionine and thiourea are two small sulfur-containing molecules with an antioxidative and scavenging effect. The passage through the r.w. of radioactive D-methionine and thiourea administered by 1 h infusion to the r.w. was studied in a rat model. Levels of the tracers were measured in scala tympani perilymph (PLT) 17-254 min after r.w. administration. Both tracers pass the r.w. membrane readily. Peak levels were found in the earliest taken samples after the administration. The radioactivity in PLT of the basal turn reached a peak to about 1.5-1.9% of the irrigating medium radioactivity. Following the r.w. administration, the concentration of radioactive D-methionine and thiourea declined with a terminal half-life of 0.57 and 0.77 h, respectively. The distribution of the tracers at the cellular level was analyzed by autoradiography. The most intense expression was found in the lateral wall of the cochlea. It can be postulated that local delivery to the cochlea of D-methionine and thiourea via the r.w. gives high local concentrations of the substances in PLT in the basal turn.

Patients' subjective evaluations of quality of life related to disease-specific symptoms, sense of coherence, and treatment in Ménière's disease.

OBJECTIVE: To evaluate the self-rated quality of life associated with vertigo, hearing loss, and tinnitus in Ménière's patients, and to identify potential relationships between these findings, treatment regimens, and sense of coherence in comparison to the classification of the American Academy of Otolaryngology-Head and Neck Surgery (AAO/HNS). STUDY DESIGN: Cross-sectional. SETTING: Tertiary referral hospital centers. PATIENTS: 112 patients with Méniére's disease, who had undergone endolymphatic sac surgery or intratympanic gentamicin injections, or were surgically untreated. MAIN OUTCOME MEASURE: Questionnaires concerning quality of life aspects and symptom-specific instruments: the Vertigo Symptom Scale (VSS), the Hearing Disability Handicap scale (HDHS), the Tinnitus Severity Questionnaire (TSQ), the AAO/HNS criteria for reporting results of treatment of Ménière's disease, and the Sense of Coherence Scale. RESULTS: A majority of the patients reported their quality of life in general as very good or good. There was no difference in general quality of life, present hearing loss, or tinnitus between the three treatment groups, but the gentamicin-treated patients had less vertigo than did the other groups. Sense of coherence showed a strong correlation to reported quality of life in all measurements. CONCLUSIONS: Even though the gentamicin-treated patients had less vertigo, no difference in overall quality of life was found between the surgically treated and untreated patients. The sense of coherence seems to be an important factor in the patient's experience of quality of life. Quality of life instruments can measure both specific symptoms and related aspects on quality of life and may give complementary information to the AAO/HNS classification in evaluating the treatment of patients with Ménière's disease.

Displacement pattern of the normal pars flaccida in the gerbil.

OBJECTIVE: The aim of the current study was to assess the mechanical stiffness properties of the normal pars flaccida and to compare the results with those obtained in earlier studies on the pars tensa. BACKGROUND: Postinflammatory changes such as retraction pockets and cholesteatoma develop in the pars flaccida as well as in the pars tensa of the tympanic membrane. In these authors' previous experimental studies, stiffness changes are shown to develop early in the pars tensa in response to purulent otitis media and otitis media with effusion. These changes are suggested to be precursors to a later development of retraction pockets and cholesteatoma. In the clinical situation, retraction pockets are often found in the pars flaccida only. This study will establish the stiffness properties of the normal pars flaccida and form a base for forthcoming studies of the pars flaccida in response to otitis media with effusion and purulent otitis media, as well as retraction pocket formation and cholesteatoma. METHODS: A measure for the mechanical stiffness properties of the normal pars flaccida in the gerbil was assessed as its displacement for a given transtympanic pressure. The method used was moiré interferometry, which is a noncontacting optical technique to measure the shape of the surface of an object. RESULTS: The displacement of the pars flaccida was a nonlinear and asymmetric function of pressure. The displacement per pressure unit rose steeply at low middle ear pressures to level out and reach a steady state at higher pressures. The displacement versus pressure characteristics for the pars flaccida strongly differed from those of the pars tensa. The pars tensa seemed more elastic. CONCLUSION: Reference values for displacement versus pressure characteristics of the normal gerbil pars flaccida were obtained using a moiré interferometry method. The mechanical stiffness properties of the normal pars flaccida were strongly different from those of the pars tensa.

Morphological and functional characteristics of cells cultured from the endolymphatic sac.

The endolymphatic sac is a part of the homeostasis-regulating system of the membranous labyrinth of the inner ear. Disturbances in the function of the endolymphatic sac are believed to be involved in the genesis of different inner ear disorders, such as endolymphatic hydrops and Ménière's disease. To make studies of the ion- and fluid-regulating mechanisms of the sac possible, a method to culture the tissue in vitro was developed. Epithelial cells and fibroblasts were morphologically characterised in the cell cultures with light and electron microscopy as well as immunohistochemically using antibodies against cytokeratin and vimentin. Since mesenchymal cells have been shown to express vimentin and epithelial cells cytokeratin, the antibodies against these two intermediate filament proteins were used to further confirm the morphological identification. In addition, some functional characteristics of the cultured cells from the endolymphatic sac were studied. ATP and K(+) were added to the cell cultures and changes in cytoplasmic free Ca(2+) concentration ([Ca(2+)](i)) were determined with the fura-2 method. A rapid and transient increase in [Ca(2+)](i) could be seen in both epithelial cells and fibroblasts after applying ATP (200 microM) extracellularly. However, when K(+) was added in concentrations of 50 mM and 100 mM, no changes in [Ca(2+)](i) could be seen in either the epithelial cells or the fibroblasts. The results show that the cultured endolymphatic sac cells preserve their morphological characteristics and maintain a high viability. Accordingly, this method provides a tool for further studies of ion transport mechanisms and fluid homeostasis in the endolymphatic sac.

A study of inflammatory mediators in the human tympanosclerotic middle ear.

OBJECTIVE: To analyze immunocompetent cells as well as 2 factors involved in inflammation and also thought to be involved in bone remodeling-interleukin 6 (IL-6) and inducible nitric oxide synthase in the human middle ear, including the tympanic membrane. DESIGN: Biopsy specimens were obtained from the human middle ear and tympanic membrane during surgery. Using an immunohistochemical technique, the expression of macrophages, T cells, B cells, IL-6, and inducible nitric oxide synthase were analyzed. MATERIALS: Nine biopsy specimens from tympanic membranes in children having a transtympanic ventilation tube inserted as a treatment for secretory otitis media and 11 biopsy specimens from tympanosclerotic plaques from patients with chronic otitis media and tympanosclerosis. RESULTS: More positively stained specimens showing macrophages, B cells, and IL-6 were seen in the biopsy specimens from children with secretory otitis media compared with the biopsy specimens from patients with chronic otitis media and tympanosclerosis. The biopsy specimens from patients with chronic otitis media and tympanosclerosis more often showed positive stainings for inducible nitric oxide synthase than the biopsy specimens from children with secretory otitis media. The presence of IL-6 and inducible nitric oxide synthase was shown by staining to be mostly in the surface cells, while macrophages and B cells were stained deeper in the tissues, in connective tissue, or around sclerotic lesions. CONCLUSIONS: The 2 patient groups differed in antigen presentation so that macrophages, B cells, and IL-6 were labeled more frequently in patients with secretory otitis media, that is, an early phase of the disease. Inducible nitric oxide synthase was seen more frequently in the patients with already established tympanosclerosis in a later phase of the disease.

Detection and localization of interleukin-6 in the rat middle ear during experimental acute otitis media, using mRNA in situ hybridization and immunohistochemistry.

OBJECTIVE: Otitis media is one of the most common diseases among children. A well-known sequela of acute, chronic, and secretory otitis media is tympanosclerosis. With the exception of surgery, there is no causal treatment available for this condition, which may cause hearing disabilities. This study aimed to describe the localization of interleukin (IL)-6 mRNA and its gene product in the rat middle ear during pneumococcal otitis media. IL-6 is known to be involved in inflammatory and bone remodeling processes. METHODS: Using an experimental model of pneumococcal acute otitis media, the expression of interleukin IL-6, was analyzed. Sprague-Dawley rats were sacrificed at different time points varying from 1 h to 6 days intervals after inoculation. The middle ears were analyzed by messenger RNA in situ hybridization, and by immunohistochemistry with cell-type specific antibodies directed against IL-6. RESULTS: Transcripts of IL-6 were observed only on day 1 post-inoculation, whereas the final gene product was observed at all intervals after inoculation. IL-6 was localized in the bony part of the bulla nearest to the mucosa, around mucosal vessels, and in the ciliae of the mucosal epithelium. The results demonstrated that IL-6 was synthesized locally as early as 1 h after bacterial middle ear challenge, and that although transcription could not be detected after 24 h, the cytokine product persisted for at least 5 days after the infection was introduced. CONCLUSIONS: IL-6 was shown to be produced early in the inflammatory process during induced pneumococcal otitis media in the rat. No production was seen after 24 h although the protein remained in the tissue for at least 5 days. IL-6 could initiate a differentiation of macrophages to osteoclasts and thereby participate in a bone remodeling process leading to tympanosclerosis development.

A comparison of the safety and efficacy of moxifloxacin (BAY 12-8039) and cefuroxime axetil in the treatment of acute bacterial sinusitis in adults. The Sinusitis Study Group.

The aim of this multicentre, randomized study was to compare the efficacy and safety of moxifloxacin (BAY 12-8039), a new 8-methoxy fluoroquinolone, with that of cefuroxime axetil for the treatment of acute bacterial sinusitis in adults. Diagnosis was made on a range of clinical signs and symptoms combined with radiology and microbiology. A 400 mg dose of moxifloxacin was administered once daily for 7 days to 242 patients and 250 mg twice daily of cefuroxime axetil was administered to 251 patients for 10 days. The clinical success rate at the end of treatment in the evaluable population was significantly higher (96.7%) in the moxifloxacin group (204/211) than in the cefuroxime axetil group (204/225, 90.7%; 95% confidence intervals 1.5%; 10.6%). At follow-up the success rate in the moxifloxacin group was 90.7% and that for the cefuroxime axetil group was 89.2% (95% confidence intervals -4.3%; 5.4%). The predominant pathogens isolated were Streptococcus pneumoniae and Haemophilus influenzae, followed by Moraxella catarrhalis and Staphylococcus aureus. The bacteriological eradication rates were higher for moxifloxacin (94.5%, 103/109) than for cefuroxime axetil (83.5%, 96/115; 95% CI 3.6%; 19.7%). Only one S. pneumoniae infection persisted following moxifloxacin therapy in contrast with three in individuals on cefuroxime axetil. There were slightly more adverse events in the moxifloxacin group than in the cefuroxime axetil group, but there were fewer serious adverse events following moxifloxacin treatment (three vs. eight). The drug was discontinued because of adverse events in 14 moxifloxacin patients and in 11 cefuroxime axetil patients. Overall, in all assessments, moxifloxacin was at least as effective clinically and bacteriologically, and as well tolerated, as cefuroxime axetil in the treatment of acute sinusitis.

Labeling of the glucocorticoid receptor and Na,K-ATPase in a rat otitis media model.

HYPOTHESIS: Glucocorticoid hormones exert an influence on the inflammatory response of the middle ear during acute otitis media. Rats with experimentally induced purulent otitis media were given either glucocorticoid hormones in excess or a glucocorticoid hormone blocker that deprived the animals of the hormone. BACKGROUND: Acute otitis media is a common inflammatory disease among children. Streptococcus pneumoniae is the most usual causative agent. The standard treatment today is phenoxymethylpenicillin. The role of glucocorticoid hormones in inflammatory reactions in the middle ear has been widely debated. METHODS: In an otitis media model, a suspension of pneumococci was inoculated into the bulla of the rat, after the animals were pretreated with either a dose of corticosteroid hormones or the glucocorticoid receptor blocking agent RU 486. Rats with induction of otitis media only, but no pretreatment, were used as control subjects, as were the left control-operated ears of all rats. The inflammatory response in the inner ear and in the middle ear was evaluated. The presence of glucocorticoid receptors and the enzyme Na,K-ATPase was investigated with immunohistochemistry. RESULTS: The inflammatory response in the animals with untreated otitis media and in the group with otitis media in rats pretreated with the receptor blocker was much more extensive than in the group of animals pretreated with corticosteroids. In the corticosteroid-treated group, the tympanic membrane and the mucous membrane of the middle ear were less edematous, but the middle ear cavity contained more pus. Only a few lymphocytes were found in the inner ears of these rats. When the inner ear was labeled with antibodies against glucocorticoid receptors, there seemed to be no difference between the labeling patterns in the three groups. This was also the case for antibody labeling against Na,K-ATPase. CONCLUSION: The present results indicate that the reaction in the middle ear mucous membrane is more pronounced in rats that had been pretreated with the hormone receptor blocking drug. An increase of corticosteroid hormone levels during the inflammatory process seem to diminish the reaction in the tympanic membrane and the middle ear mucosa. Neither the hormone receptor blocking drug nor the steroid hormones change the content of glucocorticoid receptors and Na,K-ATPase in the inner ear in the otitis media rat model.

Morphological changes of the endolymphatic sac induced by microinjection of artificial endolymph into the cochlea.

Morphological changes of the endolymphatic sac were analyzed in guinea pigs following microinjection of artificial endolymph into the cochlea or withdrawal of a quantity of native endolymph. Injections were performed into the second turn of scala media with a micro-pump at a rate of 60-100 nl/min, lasting for a period of 4, 7. 5, 15 or 18 min. In withdrawal experiments, endolymph was aspirated from the second cochlear turn over a period of 8 min. For each procedure the contralateral (non-treated) ear served as a histological control. Following artificial endolymph injections of 7. 5 min or more there was an almost total absence of the normal intraluminal homogeneous substance (HS) on the injected side. Our observations suggest that the disappearance of the HS occurs by both enzymatic and macrophagic activity. After endolymphatic withdrawals the ES was found to contain increased amounts of HS. The results could suggest that the volume of fluid in the ES, and hence the volume of the entire membranous labyrinth, may be regulated by a dynamic relationship between active secretion and enzymatic degradation of a lumen-expanding substance that is intimately related to the intraluminal macrophages. The exact mechanism governing these regulatory systems, and their relationship to ion and water movements across the epithelium of the sac, remain to be elucidated.

An immunohistochemical study of inducible nitric oxide synthase in the rat middle ear, with reference to tympanosclerosis.

Tympanosclerosis and myringosclerosis are well-known sequelae after acute and chronic otitis media and are also often seen after treatment of secretory otitis media with ventilation tubes. They sometimes cause serious hearing disability. There is no successful treatment for these conditions. There might be factors triggering an immunological or autoimmune chain reaction, which leads to tympanosclerosis. Intervention with the aim of abolishing this type of response might be possible if an interruption of the chain reaction can be found. Nitric oxide is a radical molecule with the ability to kill pathogens and is produced by the enzyme nitric oxide synthase. Expression of inducible nitric oxide synthase (iNOS) was analysed immunohistochemically in a rat model of acute otitis media. In rats sacrificed at days 3 and 6 after inoculation. iNOS was also strongly expressed in the middle ear mucosa and in the tympanic membrane as well as in the inner ear. In control specimens as well as in infected ones. iNOS was expressed in the tissue of the external ear canal. In rats sacrificed at day 10 and after 3 months, iNOS was expressed at the same locations, although less frequently. These data indicate that iNOS expression is induced during acute otitis media and suggest that nitric oxide may be important in the host defence against ear infections.

Presence of plasma membrane-bound Ca(2+)-ATPase in the secretory epithelia of the inner ear.

The Ca2+ concentration of the endolymph is low, around 0.023 mM. Yet, because of the positive endocohlear potential, Ca2+ must be actively transported into the endolymphatic space. The mechanisms responsible for the active Ca2+ transport into the endolymph are not known. In this study, the presence of plasma membrane-bound Ca(2+)-ATPase (PMCA ATPase) in the endolymph-producing, secretory epithelia of the inner ear from guinea pig was investigated with immunoblotting and immunohistochemistry. The antibody used was a monoclonal antibody which recognizes an epitope shared by all four known isoforms of PMCA ATPase. With immunoblotting, a band corresponding to PMCA ATPase was found in the stria vascularis, the ampullary tissue, the utricle and the endolymphatic sac in assays from at least three different batches of tissue. With immunohistochemistry, a strong positive staining reaction for PMCA ATPase could be seen in the stria vascularis and the dark cells of the ampullary tissue and the utricle. The epithelial cells in the endolymphatic sac showed a moderate positive staining reaction. Accordingly, in this study the presence of PMCA ATPase was shown in all the endolymph-producing, secretory epithelia of the inner ear. These results indicate that PMCA ATPase plays a role in the regulation of the Ca2+ concentration in the endolymph.

Hearing in patients operated unilaterally for otosclerosis. Self-assessment of hearing and audiometric results.

The objective of this study was to examine the outcome of unilateral stapes surgery in one patient group with bilateral hearing loss and one group with unilateral hearing loss. The patients' own estimations of improvement in hearing ability and the occurrence of other ear-related symptoms were examined retrospectively and in a follow-up study. Ninety-five of 123 patients operated for otosclerosis in only one ear between 1987 and 1992 responded to a follow-up examination. Observed audiometric findings and changes thereof, along with the patients' own estimations of their hearing handicap pre- and postoperatively, and the occurrence of other ear-related symptoms were studied. Despite good surgical results (closure of air-bone gap within 20 dB in 94%), 33% of the patients had severe hearing disabilities postoperatively, and many of these patients needed further amplification with a hearing aid. Mild dizziness occurred in 33% of the patients postoperatively and did not decrease over time. Discomfort in the operated ear due to strong sounds was reported in 20%. Change in sound quality occurred in 80% of the operated ears, but tended to disappear over time. From the results of this study it may be concluded that surgery in one ear only, leaving the other ear with poor hearing, is not an optimal hearing rehabilitation of patients with otosclerosis. It is important endevour to achieve bilateral hearing in order to give the patient good social hearing. Postoperative dizziness and unpleasant hearing quality do occur frequently, and the patients need to be informed about these problems preoperatively.

Tympanic membrane changes in experimental cholesteatoma in the gerbil.

HYPOTHESIS: The current study aimed to analyze changes of the acoustic stiffness properties and coincident morphologic changes of the tympanic membrane (TM) in early stages of cholesteatoma. The results were compared with those obtained in previous studies of otitis media with effusion and purulent otitis media. BACKGROUND: The pathophysiology of the cholesteatoma development process remains unclear. Changes of the physical properties of the TM seem to play an important role. In chronic middle ear disease, atrophic regions and retraction pockets of the TM are often present. Such changes of the TM may facilitate the development of cholesteatoma. METHODS: Early stages of external ear canal cholesteatoma were produced in the Mongolian gerbil by closing the external meatus with a suture. Acoustic admittance measurements were performed after 1, 2, or 3 months after surgery. After completed measurements, the TMs were analyzed morphologically. RESULTS: The acoustic stiffness of the TM was significantly increased in all cholesteatoma ears compared to normal control ears. A pronounced thickening and proliferative activity of the entire TM was observed in the early stage of cholesteatoma. The outer keratinizing epithelium showed an increased number of cell layers and an increased keratin production. The fibrous layer was thickened because of an increased amount of collagen fibers combined with minor edema. CONCLUSIONS: The thickness of the fibrous layer was almost doubled, mostly because of an increased amount of collagen fibers. The acoustic stiffness was significantly increased in all cholesteatoma ears. The results of the acoustic admittance measurements are comparable with those obtained in previous studies on purulent otitis media and otitis media with effusion.

Infiltration of immunocompetent cells in the middle ear during acute otitis media: a temporal study.

HYPOTHESIS: The inflammatory response to acute otitis media (AOM) is a chain reaction involving, among others, macrophages, B lymphocytes, and T lymphocytes that vary in number on different days during the infection. The response is thought to eventually contribute to tympanosclerosis (TS). BACKGROUND: In humans, TS and myringosclerosis (MS) are obscure sequelae of chronic otitis media. MS is also commonly seen in children who have had acute purulent otitis media or secretory otitis media or after treatment with ventilation tubes in the tympanic membrane (TM). It causes hearing disability, especially if the ossicles or the inner ear are affected. No successful treatment is available. This study was performed to evaluate the inflammatory stages that may lead to TS or MS. METHODS: Sprague Dawley rats were exposed to a Pneumococcus type 3 solution into the middle ear. Groups of rats were killed at 3, 6, and 10 days after inoculation. Sections from the TM specimen were stained immunohistochemically according to the avidin-biotin method. Antibodies used were directed against macrophages, T cells, and B cells. Positive cells were counted and a mean value was estimated for each slide and section for each antibody in each rat. RESULTS: Results showed that macrophages, T cells, and B cells were presented time-dependently in the acute inflammatory response in AOM. At day 3, dendritic cells, macrophages, T cells, B cells, and other major histocompatibility complex (MHC)-restricted cells were richly expressed in the whole submucosal layer and especially in the annulus fibrosus. At day 6, the amount of all positive cells decreased except for B cells and other MHC-restricted cells, which slightly increased in number. At day 10, all of the cells were lower in number than at days 3 and 6. Macrophages and possible T cells could be detected in the TM, which has not been observed earlier. Large osteoclastlike cells were present close to the bone. CONCLUSIONS: Macrophages were the first cells to invade the tissue after AOM induction. Some cells were found in the TM. Large osteoclastlike cells could be seen adjacent to the bone in the submucosa. T cells and B cells were seen in the submucosa.

Tympanic membrane displacement patterns in experimental cholesteatoma.

Tympanic membrane (TM) stiffness changes in the pars tensa in response to experimentally induced ear canal cholesteatoma by obstruction of the ear canal were studied. To this aim TM displacement versus pressure was measured with a high resolution, differential moiré interferometer. The measurements were performed on fresh, isolated gerbil temporal bones after removal of the cholesteatoma bulk. Besides an overall stiffness reduction we found that local stiffness variations were present in nine out of 18 studied ears. The stiffness changes as a function of time after ear canal obstruction had a pattern similar to those previously shown to develop in response to various forms of otitis media, showing that the TM stiffness properties decrease in a similar way in response to different inflammatory middle ear diseases. The stiffness changes correlated with an increased overall TM thickness and increased thickness of the lamina propria in particular as measured in histology sections. The stiffness changes may play an important role in the pathophysiology of cholesteatoma.

Distribution of Na,K-ATPase is normal in the inner ear of a mouse with a null mutation of the glucocorticoid receptor.

This study was performed in order to test the hypothesis that the glucocorticoid hormone stimulates the formation of Na,K-ATPase in the inner ear of the mouse. An immunohistochemical study with respect to the presence and distribution of glucocorticoid receptors (GR) and Na,K-ATPase in the vestibular and cochlear regions of the inner ear was performed on a C57BL mouse with a null mutation of the glucocorticoid receptor (GR mutant mouse). The wild type C57BL mouse and the CBA mouse served as normal controls. As expected, the homozygous GR mutant mouse showed no specific staining for GR in the inner ear. The heterozygous GR mutant mouse showed faint staining of GR in the spiral limbus, the spiral ganglion, the organ of Corti and the utricle. This staining was markedly less than in the wild type C57BL mouse. Antibody labelling of Na,K-ATPase in the inner ear showed no significant difference between the homozygous and the heterozygous GR mutant mouse as compared to the control wild type C57BL mouse or the CBA mouse. Although earlier studies have shown a positive correlation between levels of glucocorticoid hormone in serum and the concentration of Na,K-ATPase in the inner ear, the hypothesis that glucocorticoid hormones alone stimulate the formation of Na,K-ATPase in the inner ear could not be confirmed by this study. Thus other regulating substances must be considered.

Presence of glycosaminoglycans in the endolymphatic sac.

Earlier morphological investigations have revealed that the endolymph, which is present in the endolymphatic sac (ES) seems to differ from that found elsewhere in the labyrinth, in that it contains a stainable substance. Histochemical investigations indicate that this substance is rich in glycosaminoglycans (GAGs). It has been speculated that the stainable substance might play a role in regulation of fluid and ions and also, possibly, the pressure within the endolymphatic sac compartment. Endolymphatic sac specimens obtained from adult guinea pigs, rats, mice and in vitro cultured fetal inner ears were incubated with monoclonal antibodies against epitopes, and after enzymatic digestion revealed five different GAGs: hyaluronan, chondroitin-4-sulphate+dermatan sulphate, chondroitin-6-sulphate and keratan sulphate. In order to verify the specificity of these antibodies, otocysts from fetal mice were incubated in the same way. These cartilaginous specimens are known to contain GAGs in abundance and served as positive controls. The results indicate that the hyaluronan visualized by the monoclonal antibody is present to a large extent in the lumen of the ES and in the epithelial cells. Keratan sulphate and chondroitin-4-sulphate+dermatan sulphate are present within the epithelial lining, in the subepithelial tissue, and to some minor extent in the lumen, while chondroitin-6-sulphate does not show any specific staining.

Development of tympanosclerosis: can predicting factors be identified?

HYPOTHESIS: The etiological hypothesis is that there might be factors triggering an immunological chain reaction that eventually leads to tympanosclerosis formation. BACKGROUND: Tympanosclerosis is a condition leading to a calcification process in the middle ear and, occasionally, also to the lining of the inner ear. This sometimes leads to hearing loss due to fixation of the middle ear ossicles. In severe cases. deafness may occur as a result of the inner ear impairment. Surgery is the treatment offered, often with poor long-term results, and, alternatively, prescription of hearing aids. Some patients develop tympanosclerosis after mild inflammatory otitis media processes whereas some heal without tympanosclerosis after more aggressive infections. This difference may be due to individual variations in the inflammatory response. The biological mechanism of calcification in tympanosclerosis is probably similar to that occurring in other calcifying tissues due to diseases. METHODS: The present investigation was performed to develop methods for immunohistochemical analyses of this delicate tissue consisting of both hard bone and the very thin tympanic membrane. Sprague-Dawley rats were inoculated with a suspension of Streptococcus pneumoniae, type 3, into the middle ear and sacrificed after 1 week up to 6 months. A new technique was elaborated where the whole specimen was prefixed briefly and then en bloc incubated with the primary antibodies and after that decalcified in edetic acid (EDTA). Primary antibodies against macrophages were used for the immunohistochemical staining. RESULTS: Acute otitis media was successfully induced in the rats and myringosclerosis was seen in 30% of the animals, often localized close to the bony frame where macrophages could also be detected. CONCLUSIONS: Acute otitis media and myringosclerosis were introduced in the animals. Conventional immunological techniques were tested on this delicate tissue. A new method for immunohistochemical staining was elaborated in which specimens were stained en bloc before decalcification and sectioning were performed. Expression of macrophages was demonstrated in the tympanic membrane.

Tympanic membrane changes in experimental purulent otitis media.

The stiffness properties of the gerbil tympanic membrane (TM) were investigated during the early course of experimental purulent otitis media produced by middle ear inoculation (n = 49) with type 3 Streptococcus pneumoniae. In a first approach the acoustic admittance and susceptance were measured in vitro with tympanometry and in a second approach the tympanic membrane displacement in response to static pressure was measured with moire interferometry. A histological assessment of the tympanic membrane was made concurrently. The acoustic admittance and susceptance reduced during the initial days post-inoculation. These reductions seem to correlate with an oedema simultaneously developing in the pars tensa. The pressure-induced displacement increased with time of disease, i.e. the mechanical stiffness of the TM reduced. Local deformation zones, or 'weak spots' appeared in the inferior half of the pars tensa in three out of eight cases measured at 3 or 4 days post-inoculation. The loss of stiffness in the pars tensa may affect the further course of otitis media, and the 'weak spots' are possible precursors of retraction pockets and/or perforations. The stiffness reductions may be caused by changes on a sub-microscopical, molecular level.