Hearing threshold levels for an otologically screened population in Spain.

OBJECTIVE: The aim of the present study was to provide thresholds data as a function of age for an otologically normal population in Spain, compared to the current ISO 7029 (2000) standard. DESIGN: A prospective study in an otologically screened population. STUDY SAMPLE: Data was collected from 1175 otologically-normal persons aged between 5 and 90 years. Inclusion criteria involved those listed in ISO 389-1 (1998) and the 8253-1 (2010). Suitability for inclusion was evaluated through interview, based on a questionnaire, and physical examination. RESULTS: The hearing thresholds decreased slightly from 125 to 2000 Hz. From 2000 Hz onwards the thresholds increased; this increase being more pronounced with increasing frequency and age. No statistically significant sex differences were found. The hearing threshold levels in the present study were higher (poorer) than the ones provided by ISO 7029 (2000). CONCLUSIONS: Results from this study suggest that the thresholds listed in ISO 7029 (2000) may be too restrictive, and could be useful in formulating the ISO 7029 update.

Effect of intratympanic dimethyl sulphoxide (DMSO) in an in vivo model of cisplatin-related ototoxicity.

Although dimethyl sulfoxide (DMSO) is one of the most common solvents employed in otoprotection studies, its effect on the inner ear remains unknown. Only a few in vitro studies have addressed the effect of DMSO in cochlear cells. Up to the date, no in vivo functional studies have been reported. To determine the effect of intratympanic DMSO application in the inner ear, and to evaluate its effect in combination with cisplatin in Wistar rats, twelve Wistar rats were randomly assigned into two groups. Group A received intratympanic 1 % DMSO in both ears. Group B received intraperitoneal cisplatin (10 mg/kg) and intratympanic 0.5 % DMSO in the right ear and saline solution in the left ear. Functional changes were evaluated with Auditory Steady-State Responses before and 5 days after the procedure. Morphological changes were studied by means of confocal laser scanning microscopy following the removal of the temporal bones and cochlear dissection. Hearing threshold levels in group A did not show any statistically significant changes after the treatment. In group B, significant differences between pre- and post-treatment were found, with no statistically significant variations between right (DMSO) and left ear (saline solution). We suggest that DMSO could be safely used to dissolve hydrophobic compounds in otoprotection studies without interfering with the cochlear damage produced by cisplatin.

Extended high-frequency (9-20 kHz) audiometry reference thresholds in 645 healthy subjects.

OBJECTIVE: The aim of the present study was to study patterns in the extended spectrum of the human hearing (0.125 to 20 kHz) in order to obtain reference thresholds. Then, we compare our values with existing results at extended high-frequencies (8 to 20 kHz) in an attempt to establish new standards for potential international adoption. DESIGN: A prospective study in a group of otologically healthy subjects. STUDY SAMPLE: A total of 645 subjects aged between 5 and 90 years were recruited. Pure-tone thresholds were determined for conventional and extended high-frequencies. RESULTS: There was an increase in the hearing thresholds as a function of frequency and age. For the 20 to 69 years old group, thresholds were lower in females than in males, especially at 12.5 and 16 kHz. Our threshold values are comparable to those presented in previous studies that used different instrumentation and populations. CONCLUSIONS: When comparing different studies the hearing thresholds were found to be similar. Therefore, it would be possible to establish international standard thresholds.

Earphones in extended high-frequency audiometry and ISO 389-5.

OBJECTIVE: To determine common reference equivalent threshold sound pressure levels (RETSPL) for the earphones used in the extended high-frequency (EHF) range, as different earphones are commercially available, but there are not RETSPLs for each model. DESIGN: Hearing threshold sound pressure levels were measured up to 20 kHz for the Sennheiser HDA 200 audiometric earphone, and were compared to the ISO 389-5 (2006) norm and other investigations using that earphone and different ones. STUDY SAMPLE: A total of 223 otologically-normal subjects (aged 5-25 years old) participated in the hearing determination. RESULTS: The results are in good agreement with previous studies of hearing thresholds using the same and other earphones. CONCLUSIONS: The results of the present investigation are relevant for the international standard for the calibration of audiometric equipment in the 8 to 16 kHz frequency range, ISO 389-5. The data may be used for a future update of the RETSPL for circumaural and insert audiometric earphones.

Lipochoristoma of the internal auditory canal.

PROBLEM: Approximately 90% of tumours of cerebellopontine angle and internal auditory canal are vestibular schwannomas (acoustic neuromas) and meningiomas. Lipochoristomas are rare benign masses that represent only 0.15% of cases. METHODOLOGY: We report the case of a 39-year-old man who consulted us for right-sided hearing loss and tinnitus. RESULTS: Tonal audiometry showed a down-sloping right sensorineural hearing loss in frequencies above 2000 Hz. Magnetic resonance imaging (MRI) revealed a heterogeneous lesion in the right internal auditory canal with areas of hyperintensity on noncontrast T1-weighted MRI and suppression of much of the signal of the lesion with persistence of some areas of enhancement on T1-weighted fat-suppressed images. CONCLUSION: Correct imaging diagnosis through MRI (high signal intensity on noncontrast T1-weighted images together with a missing signal in fat suppression sequences) is essential in order to avoid unnecessary surgery or radiation therapy, which are not recommended in the treatment of these lesions.

Biofilm colonisation in nasolacrimal stents.

PROBLEM/OBJECTIVE: Nasolacrimal duct obstruction is a common problem. A Song stent is a useful and simple treatment with low morbidity. However, the success rate is limited, especially in long-term follow-up. The aim of the present study is to determine the presence of biofilms in failing nasolacrimal stents. METHODOLOGY: Thirty-three polyurethane nasolacrimal stents were implanted between January 2006 and December 2007 using Song's technique. Patients were followed for a mean of 21.5 months (range 11-30 months). Removed nasolacrimal stents were preserved in saline and examined using environmental scanning electron microscopy (ESEM). RESULTS: Eighteen nasolacrimal stents were removed because of the failure of the device (follow-up range 11-30 months). Seven stents were recovered for this study. Biofilms were identified in all the specimens studied. Five prostheses showed occlusion caused by mucus or granulation tissue. CONCLUSIONS: Biofilm colonisation of nasolacrimal stents could play a major role in prosthetic failure leading to stent occlusion. Mucus, granulation tissue and irregularities of the biomaterial are factors that facilitate biofilm colonisation. Non-stick material for newly developed stents or drugs capable of destroying the polysaccharide matrix should be considered as future therapeutic options.

Accumulation, fractionation, and analysis of platinum in toxicologically affected tissues after cisplatin, oxaliplatin, and carboplatin administration.

Antitumoral Pt-containing drugs present side effects like nephrotoxicity and ototoxicity. Several systematic experiments have been carried out with Wistar rats treated with cisplatin, carboplatin, and oxaliplatin to study Pt-drugs accumulation and elimination, and Pt-biomolecule distribution in the cells and cytosols of ear, kidney, and liver. Inductively coupled plasma-mass spectrometry (ICP-MS) analysis shows a cisplatin accumulation capability between oxaliplatin (the highest) and carboplatin (the lowest). The maximum concentration of Pt in all the organs studied was achieved around the first week after cisplatin treatment. During the first 30 days, the elimination was very fast, decreasing in the subsequent 60 days in all the organs. Analysis of cytosols by liquid chromatography (LC)-ICP-MS showed an analogous behavior. In most samples, the distribution of the three drugs in the cellular and cytosolic fractions was similar for all the tissues. For kidney and ear, approximately 60% and 30%, respectively, of the metal accumulated was present in the cytosol, the cytosolic fractions smaller than 50 KDa being especially important. Cisplatin-biomolecule interaction strength under denaturing conditions was evaluated by LC-ICP-MS and showed a quite strong bond.

Cisplatin-induced hearing loss does not correlate with intracellular platinum concentration.

CONCLUSION: Inductively coupled plasma mass spectrometry (ICP-MS) can be applied to organic tissues obtained from experimental animals. Hearing loss does not correlate with the platinum (Pt) concentration found in the inner ear. Drug structure and affinity to inner ear proteins could explain ototoxicity caused by cisplatin. OBJECTIVES: To analyse Pt affinity for brain and ear tissues (of similar embryologic origin) in the Wistar rat and clearance gradient after a single dose, and to correlate these findings with hearing changes. MATERIALS AND METHODS: Thirty-two Wistar rats were intraperitoneally injected with cisplatin at a dose of 5 mg/kg. Animals were sacrificed after obtaining auditory brain responses (ABRs) at 3, 7, 30 and 90 days (nine, seven, seven and nine animals, respectively). Brain and both temporal bones were extracted from each animal and analysed by ICP-MS to determine the absolute concentrations of the metal. Eight non-treated animals were employed as a control group. RESULTS: The ABR thresholds were significantly elevated in animals from all groups after cisplatin treatment. A maximum accumulation of Pt for inner ear and brain was revealed around the first week: 3.175 (57%) and 0.342 (72%), respectively. Pt significantly accumulated in greater quantities in ear than in brain (p<0.01) and was cleared at a higher rate in brain than in ear (p<0.01) following cochlea/brain ratio analysis. No statistically significant correlation was found between amounts of Pt and hearing loss in the study animals.

The anticancer drug cisplatin induces an intrinsic apoptotic pathway inside the inner ear.

BACKGROUND AND PURPOSE: Ototoxicity is a known adverse effect of cisplatin (CDDP). Since apoptosis is involved in the development of some pathological conditions associated with the administration of anticancer drugs, we examined, using immunohistochemical and electrophysiological techniques, the apoptotic changes in the cochlea of Sprague-Dawley (SD) rats after an injection of CDDP (5 mgkg(-1) body weight). EXPERIMENTAL APPROACH: Luciferase assays were used to determine the different caspase activities and ATP levels in protein extracts of whole cochleae. The expression of several apoptotic-related proteins was measured by means of Western blotting. These analyses were performed 2, 7 and 30 days after the CDDP injection. The auditory brain stem response was obtained before and at the different times after the injection of CDDP, before the animals were killed. KEY RESULTS: CDDP significantly increased the levels of caspase-3/7 activity and active caspase-3 protein expression and caspase-3 immunofluorescence staining, caspase-9 activity, and Bax protein expression but decreased Bcl-2 protein expression within the rat cochleae. Threshold shifts were significantly elevated 2 days after CDDP treatment. CONCLUSIONS AND IMPLICATIONS: These findings support the hypothesis that cisplatin-related apoptosis evokes an intrinsic pathway of pro-apoptotic signalling within the rat cochleae. Thus, selective inhibition of the sequence of events involved in the intrinsic apoptotic pathway could provide a strategy to minimize cisplatin-induced ototoxicity.

HSP-70 as a nonspecific early marker in cisplatin ototoxicity.

CONCLUSION: The great variety of pathological entities related to the presence of circulating HSP-70 suggests a nonspecific cellular damage. As the present study shows, positive results decrease with respect to the time elapsed after the injection of the ototoxic agent. HSP-70 appears as an early and transient marker that could permit early detection of inner ear damage. OBJECTIVES: The aim of this study was to determine the presence of HSP-70 at different time points by means of Western blot immunoassay in the sera of rats treated with cisplatin. MATERIALS AND METHODS: Thirty-six Wistar rats were intraperitoneally injected with cisplatin at a dose of 5 mg/kg and blood samples were collected at 7 and 90 days. Determination of HSP-70 was made by means of a modified Western blot immunoassay kit originally used for human HSP-70 antigen detection. A control group of 18 animals was used for comparison. RESULTS: Western blot was positive in 77.8% of the animals in the 7 days group, decreasing to a 44.4% in the 90 days group. In the control group, Western blot was positive in 5.5%.

Central role of supporting cells in cochlear homeostasis and pathology.

HYPOTHESIS: Supporting cells have a crucial role in degenerative and regenerative events of primary sensorial hair cells of the organ of Corti. This new role should determine future studies about pathophysiology of hearing loss and its regenerative treatment. SUPPORTING EVIDENCE: Recent findings suggest an active role of supporting cells in the maintenance of hair cell function and structure. Evidences of high energy consumption and close proximity to auditory nervous fibers suggesting K+ active exchange, preferential expression of specific proteins and antigens, presence of glucocorticoids receptors, affinity for cisplatin and regenerative potential give the supporting cells an important role in homeostasis of the organ of Corti and in some specific diseases affecting this structure. CONCLUSION: As well as glial cells provide protection and regeneration to neural tissues, supporting cells may provide the necessary metabolic and electrolitic conditions for hair cells mechanical and bioelectrical function. This opens new possibilities for the treatment of apparently "irreversible" destruction of the inner ear.

[External auditory canal cholesteatoma as a complication of ear surgery]. / Colesteatoma de conducto auditivo externo secundario a cirugía previa.

External auditory canal cholesteatomas are a rare disease. Their usual clinical appearance is a mass eroding the bony external auditory canal, normally in the inferior or anterior parts, with an intact tympanic membrane and a normal middle ear. A case of this uncommon disease with a review of the scientific literature is presented. Guidelines for the prevention, diagnosis and management are examined.

In vitro and in vivo effects of lutein against cisplatin-induced ototoxicity.

INTRODUCTION: Cisplatin is a commonly prescribed drug that produces ototoxicity as a side effect. Lutein is a carotenoid with antioxidant and anti-inflammatory properties previously tested for eye, heart and skin diseases but not evaluated to date in ear diseases. AIM: To evaluate the protective effects of lutein on HEI-OC1 auditory cell line and in a Wistar rat model of cisplatin ototoxicity. MATERIALS AND METHODS: In vitro study: Culture HEI-OC1 cells were exposed to lutein (2.5-100 µM) and to 25 µM cisplatin for 24h. In vivo study: Twenty eight female Wistar rats were randomized into three groups. Group A (n=8) received intratympanic lutein (0.03 mL) (1mg/mL) in the right ear and saline solution in the left one to determine the toxicity of lutein. Group B (n=8) received also intraperitoneal cisplatin (10mg/kg) to test the efficacy of lutein against cisplatin ototoxicity. Group C (n=12) received intratympanic lutein (0.03 mL) (1mg/mL) to quantify lutein in cochlear fluids (30 min, 1h and 5 days after treatment). Hearing function was evaluated by means of Auditory Steady-State Responses before the procedure and 5 days after (groups A and B). Morphological changes were studied by confocal laser scanning microscopy. RESULTS: In vitro study: Lutein significantly reduced the cisplatin-induced cytotoxicity in the HEI-OC1 cells when they were pre-treated with lutein concentrations of 60 and 80 µM. In vivo study: Intratympanic lutein (1mg/mL) application showed no ototoxic effects. However it did not achieve protective effect against cisplatin-induced ototoxicity in Wistar rats. CONCLUSIONS: Although lutein has shown beneficial effects in other pathologies, the present study only obtained protection against cisplatin ototoxicity in culture cells, but not in the in vivo model. The large molecule size, the low dose administered, and restriction to diffusion in the inner ear could account for this negative result.

Thalamic projections to the anterior suprasylvian and posterior sigmoid cortex: an HRP study of the "vestibular areas" of the cerebral cortex in the cat.

We have confirmed electrophysiologically the existence of an oligosynaptic vestibular projection to the cortex surrounding the rostral end of the anterior suprasylvian sulcus ( ASsS ). However, we failed to confirm a similar projection to area 3a in the posterior sigmoid gyrus. We studied the thalamic projections to each of these cortical regions by injecting small amounts of HRP in the cortex and looking for neurons retrogradely labeled throughout the thalamus. The exact location of the cortical injections was assessed cytoarchitectonically. The heaviest neuronal labeling after injections in the banks of ASsS was obtained in Po (including in this complex GMmc ). A moderate number of projections was found from VPi, VPm and VPl (the labeling in the latter being particularly prominent in a case injected in the lower bank of ASsS ), and also from VL. Occasional labeled neurons were found in the rostro-ventral part of LP. After injections in area 3a in the posterior sigmoid gyrus, which affected to a minor degree either area 3b or 4, many labeled cells appeared in the rostral and dorsal part of VPl, and in the central and lateral parts of VL. Fewer labeled cells were found in VPi, Po and LP. In most cases some occasional labeled cell was observed also in the intralaminar nuclei and in Vm.

Comparative study in tympanoplasties with nitrous oxide anesthesia.

A number of intra and postoperative accidents in close cavity surgery when using nitrous oxide have been reported. In order to check the influence of nitrous oxide anesthesia in tympanic surgery, 38 patients were operated on by the usual techniques in middle ear surgery. Half the patients received continuous nitrous oxide inhalation throughout the procedure while, in the remaining cases, the anesthetic gas was suspended 30 minutes before applying the tympanic graft. Audiological differences in both groups, as controlled at 6 and 12 months, were negligible.

Fibro-osseous lesions of the external auditory canal.

OBJECTIVES: To differentiate a novel type of benign circumscribed bone lesion of the external auditory canal from those described previously, such as exostoses and osteomas. STUDY DESIGN: Information was obtained from computed tomography (CT) images, surgical findings, and pathologic study. METHODS: Five patients (26 to 82 years old) who presented a hard, round, unilateral, skin-covered mass occluding the external auditory canal to varying degrees were studied. A CT study carried out before resection of the lesions by curettage disclosed the absence of a bony connection to the underlying structures. All the tissue specimens underwent pathologic study. RESULTS: CT and surgical findings demonstrated the absence of a connective pedicle. The pathologic findings showed lesions consisting of an osteoma-like bone formation with sparse osteoblastic areas; mature lamellar bone was observed in three cases, bone marrow containing adipose tissue and hematopoietic remnants in two, and a dense, collagenous stroma in another. They all showed irregular trabeculae, bordered by osteoid osteoblasts. In no case was there evidence of a relationship to the cartilaginous tissue or to the bony structures of the external auditory canal. CONCLUSIONS: The data obtained from the clinical, CT, surgical, and pathologic findings suggest the existence of a lesion unlike those previously known, possibly related to ossifying reactions in other parts of the organism.

Deficiency of naive T cells in patients with sudden deafness.

BACKGROUND: Although there are a number of reports concerned with the role of immunity in the sudden onset of progressive sensorineural hearing loss, there are few references dealing with the involvement of immune-mediated mechanisms in sudden deafness. OBJECTIVES: To study the phenotype of peripheral blood lymphocytes in a group of patients with sudden deafness by use of 3-color flow cytometry. DESIGN: The study was carried out prior to the start of steroid therapy. Fourteen patients underwent a follow-up study once steroid therapy had been completed. Prospective analysis, case-control. SETTING: Tertiary case referral center, ambulatory and hospitalized care. PATIENTS: Twenty-two patients (13 men and 9 women; mean age, 45.3 years) were compared with 14 healthy control subjects (9 men and 5 women; mean age, 36 years). Patients were divided in 2 groups according to their response to steroid therapy. RESULTS: Decreased numbers of both CD4+ helper cells (38.4% vs 45.5%; P = .04) and CD8+ cytotoxic cells (17.5% vs 22.3%; P = .02) were observed in patients and compared with those in the control subjects, as well as reduced numbers of CD4+CD45RA+ cells (14.4% vs 29.3%; P = .01) and CD8+CD45RA+ naive cells (18.2% vs 25.4%; P = .04). In the group of patients with a good response to steroid therapy (group 1), a tendency toward normalization of the CD4+ (pretreatment, 38.6%; posttreatment, 44.6%), CD4+CD45RA+ (pretreatment, 15.2%; posttreatment, 21.7%), and CD4+CD45RO+ (pretreatment, 21.1%; posttreatment, 18.2%) cell counts was observed, with a slight decrease in the CD8+ population (pretreatment, 18%; posttreatment, 15.7%). However, in patients with a poorer response (group 2), while there were increases in the CD4+ (pretreatment, 38%, posttreatment, 50%) and CD4+CD45RA+ (pretreatment, 12.8%; posttreatment, 16.7%) cell counts after steroid therapy, there was a significant increment in the CD4+CD45RO+ memory cell count (pretreatment, 14.1%; posttreatment, 28.5%) and low CD8+CD45RA+ counts (pretreatment, 14.6%; posttreatment, 15.5%). No differences were observed in the numbers of B or natural killer cells or in the presence of activation antigens CD25 and HLA-DR when pretreatment and posttreatment levels were compared. CONCLUSION: These results demonstrate significant abnormalities in the subpopulations of lymphocytes in patients with sudden hearing loss, suggesting the existence of immune-mediated responses in the inner ear as possible etiopathogenic factors in this entity.

Prognostic significance of natural killer cell activity in patients with laryngeal carcinoma.

BACKGROUND: For laryngeal carcinoma, the present TNM clinical staging system does not seem completely satisfactory as a guide for providing a prognosis for survival. We believe that natural killer cell activity would probably have a role in a more reliable system. Therefore, we analyzed the disease outcome with previously untreated epidermoid carcinoma of the larynx, evaluating classic clinical and pathologic factors, as well as natural killer cell activity in peripheral blood samples of the patients. OBJECTIVES: To determine the level of natural killer cell activity in patients with laryngeal carcinoma and to analyze the prognostic value of this finding when associated with other clinical and pathologic variables. DESIGN: Prospective cohort study of surveillance of laryngeal cancer. Mean follow-up of 42.8 months. SETTINGS: Tertiary care referral center and ambulatory and hospitalized care. PARTICIPANTS: We compared 81 men (mean age, 62.4 years; range, 35-89 years) with laryngeal carcinoma with 44 healthy men serving as control subjects (mean age, 57.6 years; range, 37-82 years). RESULTS: Natural killer cell activity was significantly reduced in patients who had died of cancer-related causes in comparison with tumor-free survivors. Overall actuarial survival differed significantly in histologically assessed nodal involvement and low natural killer cell activity. Use of the Cox proportional hazards regression model showed that the factors that seem to have a prognostic effect on survival are histologically determined nodal involvement and low natural killer cell activity. CONCLUSIONS: These results support the prognostic significance of the determination of pretreatment natural killer cell activity in peripheral blood samples from patients with laryngeal carcinoma and suggest that assessment of adding such a determination to the current tumor staging system is advisable.

Sensorineural hearing loss and Mondini dysplasia caused by a deletion at locus DFN3.

OBJECTIVE: To study a family with inner ear malformations and sensorineural hearing loss. DESIGN: Clinical, radiological, and genetic study of the members of a family with different degrees of sensorineural hearing loss. RESULTS: The males in the family manifested profound congenital hearing loss with severe inner ear malformations, while the only affected female had progressive hearing loss that had begun during puberty. Computed tomography showed inner ear malformations in both males, with enlarged internal auditory meatus and Mondini dysplasia. Genetic analysis disclosed a microdeletion at the locus DFN3 on chromosome X. CONCLUSION: A familial Mondini dysplasia is associated to a microdeletion at the deafness locus DFN3.

Ventral approach to the rat middle ear for otologic research.

OBJECTIVE: To describe a simple approach to the rat middle ear because there are few clear descriptions of this technique with minimal morbidity and mortality. STUDY DESIGN AND SETTING: Six male Long-Evans rats were used in this study. We designed a cervical approach to the middle ear with the purpose of creating an experimental model of ossiculoplasty that permits the postoperative survival of the animal. RESULTS: It was possible in all cases to visualize the majority of structures of the tympanic cavity: promontory, round window, stapedial artery, stapes, incus, and tympanic membrane. There were no cases of postoperative infection or facial paralysis. CONCLUSIONS AND SIGNIFICANCE: The ventral approach to the rat middle ear is a rapid and simple technique that makes the rat the animal of choice for many otologic investigations.