Pathogenesis of Meniere's disease: treatment considerations. Preface.
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Ear, Inner↗
Biomedical subjects
Michael M Paparella
Publications and source records attributed to Michael M Paparella.
Revision of endolymphatic sac surgery for recurrent Meniere's disease.
Understanding the pathogenesis of Meniere's disease can result from studying its natural history; however, a marvelous opportunity for this understanding exists in surgical revisions of endolymphatic sac enhancement. In addition to avoiding destructive procedures, revision of endolymphatic sac enhancement has restored health to many patients. The procedures and findings from such revisions, which are briefly described in this article, have provided the best opportunity for the author to understand and observe the pathogenesis of Meniere's disease.
Adult↗
Induction of mucous cell metaplasia in the middle ear of rats using a three-step method: an improved model for otitis media with mucoid effusion.
Otitis media with mucoid effusion, characterized by mucous cell metaplasia in the middle ear cleft and thick fluid accumulation in the middle ear cavity, is a common otological disease that frequently affects young children. Multiple factors are involved in the development of this disease, especially middle ear infection and Eustachian tube dysfunction. In this study, in order to induce otitis media with effusion in rats, we introduced a three-step method, namely inoculation of Streptococcus pneumoniae at 10(7) colony-forming units (CFU)/ear or Haemophilus influenzae at 5 x 10(7) CFU/ear into the middle ear cavity twice at 2-week intervals, followed by Eustachian tube obstruction (ETO) for 4 and 8 weeks. Animals inoculated with phosphate-buffered saline (PBS) twice in the same manner followed by ETO served as controls. Middle ear effusion and mucosa were harvested for evaluation of carbohydrate concentrations and mucous cell density, respectively. We found that rats inoculated with S. pneumoniae twice, followed by ETO at 8 weeks, yielded the highest carbohydrate concentration in middle ear effusion and the highest goblet cell density in the middle ear cavity compared to the H. influenzae and PBS groups. It is tentatively concluded that inoculation of S. pneumoniae at 10(7) CFU/ear into the middle ear cavity of rats twice at 2-week intervals, followed by ETO for 8 weeks, is a promising animal model for otitis media with mucoid effusion which may be valuable for studying the human counterpart.
Animals↗
Temporal bone histopathology related to cochlear implantation in congenital malformation of the bony cochlea.
HYPOTHESIS: Histopathologic findings in temporal bones with congenital malformations of the bony cochlea may provide insight into cochlear implantation planning, surgical approach, and complications. BACKGROUND: Patients with congenitally malformed cochleae account for an increasing percentage of candidates for cochlear implantation. Few studies on the relationship between histopathologic findings of temporal bones with malformation of the bony cochlea and cochlear implantation have been reported. METHODS: We studied 21 temporal bones from 12 cases with congenital malformations of the bony cochlea. Ages ranged from stillborn to 50 years. Length of the cochleae and dimensions of facial recesses were measured with light microscopy. Other malformations associated with a shortened cochlea were determined, emphasizing how they affect cochlear implantation. RESULTS: The average length of the malformed cochlear duct was 22.84 +/- 0.69 mm. Average dimensions of facial recesses were not significantly different between malformed cochleae and the controls. Other malformations included enlarged cochlear aqueduct (43%), abnormal facial nerve course (57%), enlarged vestibular aqueduct (52%), aplasia of the middle ear (19%), malformed ossicles (67%), abnormal oval window (57%), and abnormal round window (29%). CONCLUSION: A shortened cochlear duct may cause an incomplete insertion of the implant electrode. Because dimensions of the facial recesses are similar to normal cases, a facial recess surgical approach is recommended. An enlarged cochlear aqueduct may cause perilymphatic oozing or gushing on fenestration of the cochlea. An anomalous course of the facial nerve is a common finding. Tympanic malformations such as round and oval window deformities and small middle ear cleft should be noted preoperatively to better guide surgery.
Adolescent↗
Induction of mucous cell metaplasia by tumor necrosis factor alpha in rat middle ear: the pathological basis for mucin hyperproduction in mucoid otitis media.
Mucoid otitis media (MOM), one of the leading causes of acquired hearing loss in children, is characterized by mucous cell hyperplasia in the middle ear cleft associated with mucin accumulation in the middle ear cavity. The factors that stimulate mucous cell metaplasia-hyperplasia and mucin hyperproduction are poorly understood. Recent studies demonstrated that tumor necrosis factor alpha (TNF-alpha), present in human middle ear effusion, stimulated mucin production in vitro and up-regulated mucin gene expression in vivo. These findings suggest that TNF-alpha is important in the development of mucous cell metaplasia-hyperplasia. This study demonstrated that inoculation of TNF-alpha into the middle ear cavity followed by eustachian tube obstruction stimulated mucous cell metaplasia-hyperplasia in the middle ear cleft, accompanied by abundant mucin or mucin-like glycoproteins in the middle ear effusion--a phenotype of MOM in humans. This finding suggests that TNF-alpha plays a key role in the pathogenesis of MOM through induction of mucous cell metaplasia-hyperplasia and mucin production.
Animals↗
Recent advances in otitis media. 4. Anatomy, cell biology, pathology, and animal models.
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Animals↗
Effects of gentamicin on sensorineural elements of the cochlea in human temporal bones.
PURPOSE: Gentamicin is commonly prescribed for treatment of gram-negative bacterial infections. It has, however, been known to have vestibulotoxic and ototoxic effects in humans. Previous studies were confounded by the use of other types of ototoxic drugs, higher than therapeutic doses, and prolonged time periods between gentamicin administration and death. The purpose of this study is to observe the effects of parenteral gentamicin administration on the sensorineural elements of the cochlea in which the previously described factors did not exist. MATERIALS AND METHODS: Temporal bone specimens were divided into 2 groups. Group 1 included 16 "normal" temporal bones with no history or histopathologic findings of otologic disease or ototoxic drug administration, and group 2 included 17 temporal bones that received gentamicin treatment within 6 months before death. Temporal bones were excluded from group 2 if patients had histopathologic findings or history of otologic disease and/or other ototoxic drugs. All temporal bones were examined under light microscopy. RESULTS: The percentages of intact outer hair cells in the basal turn was significantly greater in group 1 compared with group 2. There was no significant difference in hair cell number between the groups in the other turns. There was no significant difference in the number of spiral ganglion cells between groups in any turn. CONCLUSION: Although gentamicin is primarily considered to be vestibulotoxic, this study showed that gentamicin can damage sensorineural elements of the cochlea, even in younger patients. During the administration of this drug, hearing of the patient should be carefully monitored.
Adolescent↗
Tympanic membrane changes in central tympanic membrane perforations.
PURPOSE: The objective of this study was to evaluate the histopathological changes in central tympanic membrane perforations caused by chronic otitis media without cholesteatoma. MATERIALS AND METHODS: Twenty-nine temporal bones from 25 patients (13 male patients and 12 female patients) with central tympanic membrane perforations-18 chronic otitis media with perforation and 11 chronic otitis media with perforation caused by ventilation tubes-and 30 aged-matched normal temporal bones were included in this study. A scale was used to evaluate the extension of the migration of stratified squamous epithelium in the inner surface of the tympanic membrane. The thickness of tympanic membranes was measured halfway between the annular ligament and the perforation and compared with that of the normal bones. The presence of tympanosclerosis and papillary projections of squamous epithelium was also noted. RESULTS: The extension of the migration of stratified squamous epithelium in the inner surface of the tympanic membrane was observed in 11 of the 29 perforations (38%). The thickness of tympanic membranes was significantly different between the perforation groups and the control group. Of the 29 tympanic membranes, 13 (44%) had tympanosclerosis and 8 (28%) revealed papillary projections of squamous epithelium. CONCLUSIONS: Our study shows that a central tympanic perforation should not merely be considered as a simple defect. Most of the tympanic membranes showed one or more signs of sequelae or persistent abnormalities such as tympanosclerosis, papillary projections, thickening, and ingrowth without significant differences between the 2 central perforation groups.
Adolescent↗
Otosclerosis: etiopathogenesis and histopathology.
Otosclerosis is a disease of the bony labyrinth manifesting clinically as a progressive conductive hearing loss, a mixed-type hearing loss, or a sensorineural hearing loss. The age of onset of the hearing loss caused by otosclerosis is principally between 15 and 40 years. Although histopathological inner ear changes due to otosclerosis have been very well documented, the true etiopathogenesis of the disease has yet to be described despite intensive research. Both genetic and environmental factors have been implicated, however.
Age of Onset↗
Chronic silent otitis media.
Otitis media occurs along a continuum. For example, otitis media with effusion characterized by fluid pathology can lead to chronic otitis media plus chronic mastoiditis, characterized by the presence of intractable tissue pathology such as cholesteatoma, cholesterol granuloma or granulation tissue. The literature defines chronic otitis media as having a tympanic membrane perforation and otorrhea. Amongst many other sequelae, which can result from the continuum, an important common one is chronic silent otitis media. This overlooked entity which includes pathology beneath an intact tympanic membrane is commonly seen in our human temporal bone laboratory and in patients. The clinical pathological correlates of this important disease are discussed herein.
Cholesteatoma, Middle Ear↗
Role of macrophage migration inhibitory factor in paranasal sinus mucocele.
BACKGROUND: Little is known about the immunologic aspects and the pathogenesis of the paranasal sinus mucocele. METHODS: The fluids of paranasal sinus mucoceles were obtained from 12 subjects. The concentration of macrophage migration inhibitory factor (MIF), interleukin 1beta, tumor necrosis factor alpha, and regulated on activation normal T cell expressed and secreted (RANTES) were determined by enzyme-linked immunosorbent assay, and the levels of endotoxin were detected with kinetic Turbidimetric Assay. RESULTS: MIF and endotoxin were detected in the fluid of all samples, whereas interleukin-1beta and RANTES were detected in 1 and 3 subjects out of 12 samples. Tumor necrosis factor alpha was not detected in any of the samples. A significant positive correlation between the levels of MIF and the period with symptoms such as pain, swelling of face, and visual disturbance was observed. CONCLUSION: These findings suggest that MIF and endotoxin may play an important role in the pathogenesis of paranasal sinus mucocele. MIF may be an important factor causing the development and exacerbation of the disease.
Aged↗