The impact of a relaxation technique on the lipid profile

In this study, a more subtle animal model of Menière's disease is investigated by damaging the distal portion of the endolymphatic sac by dissection or cauterization to produce mild dysfunction of endolymphatic outflow. Cauterization resulted in low degrees of hydrops without any correlation with the inflicted damage. Total dissection of the distal portion of the sac adjacent to the sigmoid sinus produced moderate to severe endolymphatic hydrops with interanimal variation. The consequences of these relatively severe effects, in relation to the mild damage of the endolymphatic sac, and the influence on damaged and undamaged parts of the endolymphatic sac will be discussed.     

Suitable fixation condition for rat liver using microwave irradiation and its application to the immunohistochemistry of glutamate dehydrogenase

In 50 patients auditory threshold and brain stem evoked potential studies were carried out before and after myelography. Due to the analysis of amplitudes and latencies of auditory brain stem measurements, significant functional disorders of the hearing organ and the auditory pathway could be demonstrated. In most of the patients these functional disorders were found to be subclinical, whereas 12 patients showed alterations extending from a subjectively slight hearing loss to an audiometrically objectified acute hearing loss depending on its intensity in each case. The reasons of these functional disorders could not be clarified. An open cochlear aqueduct through which perilymph enters the subarachnoidal space leading to a secondary endolymphatic hydrops can be considered as the cause in cases where manifest symptoms develop. The changes in brain stem audiometry can be additionally explained by changes in osmolality of the inner ear fluids which may lead to the development of an endolymphatic hydrops.     

Immune-mediated inner ear disease: report of clinical cases

Many clinical and experimental studies have obtained evidence of immune-mediated inner ear disease. Discrepancies between theories of the mechanisms of injury to the inner ear and the laboratory tests that identify it mean that the diagnosis is based on clinical symptoms and a positive response to treatment. We report four cases of immune-mediated inner ear disease characterized by endolymphatic hydrops, fluctuating hearing loss, sudden deafness (first symptom of primary Sj?gren's syndrome), and rapidly progressive sensorineural hearing loss.     

Dexamethasone perfusion of the labyrinth plus intravenous dexamethasone for Ménière's disease

Recent clinical and laboratory evidence indicates that Meniere's disease is an immune-mediated disease. Dexamethasone perfusion of the inner ear through the round window plus intravenous dexamethasone often will stop the dizzy spells, reduce the fullness and low-frequency tinnitus, and sometimes improve the hearing in patients with Meniere's disease. The dexamethasone must act mostly on the endolymphatic sac and, to a lesser extent, on the stria vascularis and spiral ligament, the known targets of immune response in the inner ear, to reduce the endolymphatic hydrops and restore the fluid dynamics of the endolymph. Despite the good results with streptomycin perfusion, the number of patients with further hearing loss is large, so dexamethasone perfusion with intravenous dexamethasone should be tried first. The initial response to dexamethasone perfusion plus intravenous dexamethasone has been very good, with very little risk of further hearing loss, and it holds great promise for the future.     

Alterations in the distributions of the basement membrane components after secondary inner ear immune reaction in guinea pigs

Alterations in the distributions of type IV collagen (C-IV), laminin (La), and fibronectin (Fib), which are important components of the basement membrane, in the inner ear following secondary endolymphatic sac immune response were studied immunohistologically using control animals for comparison. Endolymphatic hydrops developed following direct secondary keyhole limpet hemocyanin (KLH) challenge to the endolymphatic sac in systematically pre-sensitized animals. In the endolymphatic sacs of control animals, C-IV and La were localized continuously just under epithelial cells whereas Fib was present intermittently in subepithelial connective tissue. In the endolymphatic sac, following secondary KLH challenge, linear subepithelial localizations of C-IV and La were interrupted, thinner and more loosely aggregated with numerous inflammatory cellular infiltrates on days 2-4. Following these changes, endolymphatic hydrops in the cochlea developed and peaked on days 4-7. On days 1-7, Fib was strongly but sporadically localized in subepithelial cells. These results suggest that C-IV and La may play important roles in the regulation of endolymph whereas Fib may be related to the restoration of injured endolymphatic sac tissue in animals exposed to a secondary challenge.     

cis-Elements in the 5''-region of the Oct-1 gene. Possibilities of autoregulation

The anti-diuretic hormone vasopressin (AVP) regulates water excretion from the kidney by increasing the water permeability of the collecting duct. AVP binds to V2-receptors and induces the translocation of aquaporin-2 water channels (AQP-2) into the apical plasma membrane of principal cells. By this mechanism AVP controls water reabsorption in the kidney. The effects of AVP on the endolymphatic sac (ES) of the inner ear, which is thought to mediate reabsorption of endolymph, were investigated. Both the V2-receptor and the AQP-2 water channel were found to be expressed in the ES epithelium. In the ES AVP binds to receptors most probably of the V2-subtype. Application of AVP to organotypically cultured ES inhibits membrane turnover in ribosomal-rich cells of the ES epithelia, which is thought to mediate translocation of AQP-2 into the surface membrane. This suggests that AVP has contrasting effects in the inner ear and kidney, which may be physiologically useful for maintaining endolymphatic pressure during severe hypovolemia. Animal experiments show that AVP causes endolymphatic hydrops after systemic application to guinea-pigs, which suggests a causal role for the increased AVP levels found in humans suffering from Ménière's disease.     

Secondary amenorrhoea and oral contraceptives

Extirpation of the endolymphatic anlage of the ear vesicle or that part of the ear placode which develops into the endolymphatic anlage in chick embryos, resulted in the absence of the endolymphatic system. In specimens of which the endolymphatic anlage was removed on the fourth day, healing of the wound was completed soon after the fifth day of incubation. Most of these experimental animals developed endolymphatic hydrops at a later stage. However, where healing was delayed after the fifth day, the open wound acted as an escape route for the endolymph (thus preventing further closure) which at that stage (or soon after) reached an appreciable volume.     

Delayed endolymphatic hydrops: an analysis of 12 cases

Delayed Endolymphatic Hydrops (DEH) is a clinical entity which is characterized by an early phase with a profound sensorineural hearing loss in one ear. After a prolonged period of time (from 1 to 68 years) a late phase of the disease appears with different otologic symptoms. The ipsilateral type of endolymphatic hydrops appears in the deaf ear with consequent episodic vertigo. The contralateral type develops symptoms of endolymphatic hydrop in the previously normal ear, with the onset of fluctuating hearing loss and/or episodic vertigo. This paper is a review of 12 cases of DEH (7 ipsilateral and 5 contralateral, age ranging from 19 to 79 years). Diagnosis was established on the basis of clinical history and the results of audio-vestibular investigations, specifically designed to detect signs of endolymphatic hydrops (including the glycerol-test and neuroradiological imaging of the cerebello-pontine angle). In 8 patients the levels and frequency of anti-collagen I-II-IV-V, anti-laminin autoantibodies, complement, Ig and immuno-complexes were measured. Viral infections (measles, mumps, influenza) were thought to have caused the early phase in 6 cases. In the entire group of 12 patients the delay between the onset of the ear loss and vertigo averaged 12 years. In the group of the ipsilateral DEH, caloric tests showed in 5 cases a reduced or absent response of the deaf ear. About contralateral DEH, caloric tests showed bilateral reduced response in 2 cases, and, in 3 cases, a decreased response only in the previously normal ear. Regarding immunological study, an abnormal level of Ig and Complement was detected in 3 patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Summating potential and action potential ratio in Meniere's disease before and after treatment

OBJECTIVE: This study aimed to compare the summating potential and action potential ratio (SP:AP) in patients with Meniere's disease before and after various surgical and medical treatments as an indication of change in endolymphatic hydrops to study the progression of Meniere's disease. STUDY DESIGN: The study design was a retrospective case review. SETTING: The study was conducted at an otology-neurotology referral center. PATIENTS: Eighty-eight ears of 84 patients with Meniere's disease received medical treatment in 18 ears and surgical treatments including endolymphatic shunt in 12 ears, streptomycin perfusion of the lateral semicircular canal in 9 ears, streptomycin perfusion of the middle ear in 33 ears, and dexamethasone perfusion of the middle ear in 16 ears. INTERVENTION: Transtympanic electrocochleography (ECoG) was performed in all patients before treatment and 1-57 months after treatment (mean, 13.5 months) with a 2-year interval in 28 patients. MAIN OUTCOME MEASURE: An enlarged SP:AP ratio (> or = 0.40) was used as the diagnostic criterion for endolymphatic hydrops. RESULTS: Overall, an enlarged SP:AP ratio was found in 75% of ears before treatment and 78% after treatment. The SP:AP ratio, when enlarged, remained enlarged in 91% of ears. A nonenlarged SP:AP ratio before treatment became enlarged after treatment in 41% of ears. In American Academy of Otolaryngology-Head and Neck Surgery stage 1 Meniere's disease (pure-tone threshold average < or = 25 dB), an enlarged SP:AP was found in 58% of ears before treatment and 79% after. Twenty-five (89%) of 28 patients followed for 2 years were free of vestibular symptoms after treatment, and in 22 patients (79%), the SP:AP remained enlarged. The distribution of an enlarged SP:AP ratio was associated with the duration of disease (chi-square = 33.5552, p < 0.01). CONCLUSIONS: The development of endolymphatic hydrops, as indicated by an enlarged SP:AP, is part of the progression of Meniere's disease. The longer the duration of the disease, the more likely the SP:AP ratio will be enlarged. These findings indicate that endolymphatic hydrops as detected by ECoG was not reversed in this study by the treatments used. Despite the absence of definitive spells of vertigo in most patients, endolymphatic hydrops as evidenced by an enlarged SP:AP ratio persisted.     

Laboratory experience with experimental endolymphatic hydrops

Experimental endolymphatic hydrops refers to the creation of hydrops in the experimental animal and represents a histologic correlate for Meniere's disease. Details of the surgical means to create this condition in guinea pigs are provided. Alterations in endolymph fluid composition and relative endolymph pressure occur with hydrops. Deterioration in auditory and vestibular function secondary to hydrops can develop.     

Antigen removal after inoculation into the endolymphatic sac of immunized guinea pigs

Antigen removal in the endolymphatic sac (ES) was immunohistochemically examined. Forty-five adult female Hartley guinea pigs were used in this study. After keyhole limpet hemocyanin (KLH) systemic immunization, KLH was directly injected into the lumen of the right ES. The presence of KLH was detected in histological sections using immunohistochemistry. After KLH challenge into endolymphatic sac lumen, high concentrations of KLH were diffusely found within phagocytes in the endolymphatic lumen and peri-saccular tissue on day 2. After day 14, KLH disappeared from the immunized inner ear. The above results suggest that KLH is removed from the inner ear by diffusion through the endolymphatic epithelial cells which have altered permeability or by phagocytosis of the phagocytic cells. No KLH was observed in the left endolymphatic sac and bilateral cochlea as well as vestibular organ during 5 months of follow up. This study showed that the endolymphatic sac is capable of appropriately trapping macromolecule, KLH antigen (molecular weight: about 400 KDa), and removing antigens quickly from the inner ear.     

Meniere's disease of syphilitic etiology

Congenital or acquired syphilis is the cause of Meniere's disease in six percent of all cases. The pathogenesis is endolymphatic hydrops and osteitis of the otic capsule which produces the characteristic fluctuating hearing loss, tinnitus and ear pressure associated with episodic spells of vertigo. The ear symptoms are, at first, typical of Meniere's disease of other etiologies. Failure to establish the specific etiologic diagnosis can result in unnecessary surgical treatment or inappropriate medical therapy. In some cases, if a steroid, the specific treatment, is not given promptly, hearing can be quickly and permanently lost. The etiology is confirmed by obtaining a reactive fluorescent treponema antibody absorption (FTA-abs) test. The clinical features and natural history of Meniere's disease of syphilitic etiology are unique. Ear symptoms often begin in the fifth decade of life, first in one ear and, after a few years, involving the second ear. Reduced or absent caloric responses are characteristic. When hearing loss is severe and sudden, this condition represents a true medical emergency and should be treated with prompt administration of steroids. An endolymphatic subarachnoid shunt operation is occasionally necessary as adjunctive management. An analysis of 34 cases shows that long-term use of steroids can maintain effective hearing for more than 20 years.     

Pathology of the endolymphatic duct and sac in inner-ear hydrops

The morphological substrate of Menière's disease is the endolymphatic hydrops. That can be idiopathic or secondary as a sequence of a labyrinthine disease of another cause. It is possible to coordinate function loss of the sensory end-organs and pathohistological findings, but not all failures are light-microscopically explainable. The reason for the hydrops is certainly a disturbance in the endolymph physiology. For the pathogenesis are important, besides the biochemistry of the inner ear-fluids, problems of the membranes and pathological changes on ductus and saccus endolymphaticus and perimacular areals and plana semilunata. The perilymphatic space, documentated on the example of the secondary hydrops, is certainly not only passively enrolled in the procedure. All observations bring the initiation and periodicity of attacks to another point of view. A complete solution has not been possible so far, especially in the case of the etiology in idiopathic hydrops.     

Evaluation of the cochlear aqueduct patency: comparison of 2 noninvasive techniques

Variations in cephalo-rachidian fluid pressure can be transmitted to the middle ear through the cochlear aqueduct (CA). This gives us a non-invasive manner to evaluate any changes in fluid pressure by measuring middle ear impedance (impedancemetry). The present study compared two indirect methods for measuring intracranial pressure: a) impedancemetry during evoked jugulo-tympanic reflex (JTR) and b) study of the tympanic membrane (TM) fine motility using a MMS-10 analyzer. The latter is a new procedure involving the indirect evaluation of the fluid pressure. In fact, when the CA is open the labyrinthine fluid pressure is transmitted to the oval window, the stapes platina and, finally, to the tympanic membrane where it can be measured with an MMS-10 unit. This equipment can measure nanoliter shifts in the TM. In particular, comparison between the clinostatic and orthostatic tympanic motility measurements enable one to establish whether the CA is patent or not. In the present study 15 subjects were examined using both a) impedancemetry during jugular compression and b) analysis of the TM shift using an MMS-10 unit. In 14 of the 15 cases there was good correlation between the data obtained using both methods: in all but one case it proved possible to record a JTR-induced variation in impedance whenever the MMS-10 indicated that the CA was open. The results suggest that, in clinical practice, the two methods can be used in parallel for non-invasive monitoring of variations in intracranial pressure in patients with neurological involvement. On the other hand, in the E.N.T. field these techniques could be used to study inner ear pathologies causing dynamic alterations of the endolabyrinth fluids (endolymphatic hydrops, labyrinthine fistula).     

Aspects on endolymphatic sac morphology and function

Morphological evidence indicate that the main function of the endolymphatic sac is to act as a reabsorptive and defensive mechanism for the inner ear. This activity is markedly enhanced in labyrinthine trauma, such as injection of foreign particles into the labyrinth, blocking of the endolymphatic duct, and cryosurgical destruction of vestibular sensory epithelia. Light and dark epithelial cells of the intermediate portion of the sac are capable of reabsorbing endolymph and digesting cellular debris respectively. The extensive capillary network surrounding the endolymphatic sac exhibits endothelial characteristics suggestive of active fluid transport. The "dynamic-flow theory" of endolymph circulation suggests that a radial-flow should be considered for energy metabolism and ion exchange around the sensory cell regions whereas a longitudinal-flow should be considered for reabsorption of endolymph and disposal of high molecular waist products and debris by the endolymphatic sac. The earlier concepts of endolymph circulation thus need not any longer be considered conflicting.     

An experimental model for the study of endolymphatic hydrops in sharks: implications for the clinician

In recent years, attention has focused on the role of the endolymphatic sac (ELS) and the endolymphatic duct (ELD) in the pathogenesis of endolymphatic hydrops (ELH). Changes have been noted surgically and radiographically by others in the ELS and ELD in patients with ELH. This report summarizes the development of a shark model with which to study the pathophysiology of ELH. The background material and overall results of anatomic, histopathologic, and ultrastructural studies using the model are presented. Possible implications for the clinical handling of ELH as a result of this work is emphasized.     

Further characterization of the DFNA1 audiovestibular phenotype

BACKGROUND: Autosomal dominant, nonsyndromic, hereditary hearing impairment in a large Costa Rican kindred is caused by a mutation in the human homolog of the Drosophila diaphanous gene. OBJECTIVE: To further characterize the phenotype of DFNA1 with comprehensive audiovestibular evaluation and computed tomography of the temporal bone. PATIENTS: One affected child and 2 affected adults of the Costa Rican kindred who harbor a mutation in the diaphanous gene. SETTING: Medical Center at the University of California, San Francisco. INTERVENTION: Otologic and neuro-otologic examination; pure tone audiometry, speech audiometry, and immitance testing; auditory evoked potentials, electrocochleography, and otoacoustic emissions; electronystagmography and vestibular autorotation tests; and computed tomography of the temporal bone. RESULTS: The youngest subject, an 8-year-old boy, had a mild hearing loss, intact stapedial reflexes, otoacoustic emissions at high frequencies, normal auditory evoked potentials, and electrocochleographic findings consistent with endolymphatic hydrops. The two adults had severe to profound bilateral sensorineural hearing impairment. Electronystagmography disclosed normal vestibular function. Computed tomography demonstrated normal external, middle, and inner ear structures. CONCLUSIONS: These results suggest that the early low-frequency hearing loss in this family is associated with endolymphatic hydrops. Elucidation of the role of the diaphanous gene in hearing will therefore lead to a better understanding of the mechanism of endolymphatic hydrops.     

Endolymphatic subarachnoid shunt failure caused by Silastic allergy

During the period from 1964 through 1994, the endolymphatic subarachnoid shunt operation was initially successful in eliminating endolymphatic hydrops and the symptoms and findings it produces in 76% of 645 ears of patients with Meniere's disease. After initial success, lasting from five weeks to nine years, endolymphatic hydrops suddenly returned due to obstruction of the Silastic shunt tube in 11% of patients. In these cases, prompt revision can often restore an initial good result. Histologic and immunologic examination of the material surrounding and occluding the tubes showed an allergic response to the Silastic material in most instances. Efforts to eliminate this cause of failure using a tube of new design and different plastic material are described.     

Diagnostic testing for endolymphatic hydrops

The development of a sensitive and specific diagnostic test for endolymphatic hydrops has eluded investigators for over 30 years. The absence of such a test has hampered basic and clinical research into Meniere's disease and related entities. Presently used tests are limited in their applicability because of their low sensitivity and specificity and a poor understanding of the underlying physiologic principles. Despite this, it is generally agreed that some of these studies have merit in selected situations. This article reviews the present state of diagnostic testing for endolymphatic hydrops. The use of nonspecific studies, such as basic audiometry and tests for recruitment, and "specific" studies, such as electrocochleography and dehydration testing, are critically reviewed.