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At least 163 records · Page 9Linked to original sources
PubMed1987

Allergies to ear moulds. A study of reactions encountered by hearing aid users to some ear mould materials.

In recent years, a number of people have encountered some form of otitis externa due, it was suspected, to the use of acrylic ear moulds. The intention of this study was to discover whether the reaction was purely allergic or if it was due to various other causes. Having eliminated reactions due to ill-fitting ear moulds, friction sores or lack of hygiene, a study of 25 people with ear mould problems was carried out. These consisted of three groups; those who had no other ear or skin trouble, those who had existing otitis externa and/or other skin trouble, and those who suffered with ear infections or were prone to ear infections. A sample of the population who did not wear hearing aids was taken as a control.

Dermatitis, Contact↗
PubMed1977

[Chronic mucous effusions of the middle ear and the influence on inner ear function (author's transl)].

Audiometric recordings of children suffering from chronic mucous effusion of the middle ear have revealed a statistically significant and permanent sensorineural hearing loss of high frequences. Attemps for mechanical or physical factors as explanation are not convincing. We believe that inner ear disturbances in chronic mucous effusion rise by direct intoxication of the basal turns of the cochlea caused by pathologic alterations of mucous membrane tissue. Certain substances like lysozymes or histamine are supposed to diffuse via round window membrane to the inner ear. On the other hand mucous effusion which fills the middle cavity prevents oxygen to diffuse from the middle ear to the inner ear. Maass et al. (1976) and Morgenstern (1977) clearly have shown that under physiological conditions oxygen tension in the perilymph of the basal cochlear turn partly depends on diffusion from the middle ear. The results of our clinical observations indicate that early diagnosis and prompt treatment is necessary to prevent permanent sensorineural hearing loss of high frequencies, especially in infants and children.

Audiometry↗
PubMed1998

Molecular cloning of a zinc finger gene eZNF from a human inner ear cDNA library, and in situ expression pattern of its mouse homologue in mouse inner ear.

We have isolated and characterized the cDNA for eZNF, a zinc finger gene expressed in human inner ear, from a kinetically enriched human inner ear cDNA library. The sequence of full length cDNA was determined and its expression pattern characterized. A high degree of homology is shared between eZNF and rat transcription factor Kid-1. It belongs to the C2H2 class of zinc finger genes, contains a Kruppel-associated box (KRAB) domain near the N-terminus, and has consensus sites for phosphorylation. The gene is expressed in kidney and inner ear structures of mouse and human as determined by Northern blot analysis. In situ hybridization was used to demonstrate specific expression of the mouse eZNF homologue in epithelial layers of the saccule, semicircular canals, and the cochlea of newborn mice. The genomic clone corresponding to the cDNA was isolated and used for fluorescence in situ hybridization to localize it to human chromosome 5qter. The identification of genes expressed in human inner ear by representational difference analysis, their chromosomal location, and expression pattern of their homologues in developing mouse inner ear comprise a strategy that can potentially identify genes important in hearing and deafness.

Amino Acid Sequence↗
PubMed1998

Autoregulation of human inner ear blood flow during middle ear surgery with propofol or isoflurane anesthesia during controlled hypotension.

UNLABELLED: We used controlled hypotension to obtain a bloodless cavity during middle ear surgery under an optical microscope. No previous study has assessed the effect of controlled hypotension on inner ear blood flow (IEF) autoregulation in humans receiving propofol or isoflurane anesthesia. In the present study, the IEF autoregulation was determined using laser Doppler flowmetry in combination with transient evoked otoacoustic emissions (TEOAEs) during controlled hypotension with sodium nitroprusside in 20 patients randomly anesthetized with propofol or isoflurane. A coefficient of IEF autoregulation (Ga) was determined during controlled hypotension, with a Ga value ranging between 0 (no autoregulation) and 1 (perfect autoregulation). During controlled hypotension with propofol, IEF remained stable (1%+/-6%; P > 0.05) but decreased by 25%+/-8% with isoflurane (P < 0.05). The Ga was higher during propofol anesthesia (0.62+/-0.03) than during isoflurane anesthesia (0.22+/-0.03; P < 0.0001). Under propofol anesthesia, there were individual relationships between TEOAE amplitude and change in IEF in four patients. Such a correlation was not observed under isoflurane anesthesia. These results suggest that human IEF is autoregulated in response to decreased systemic pressure. Furthermore, isoflurane has a greater propensity to decrease cochlear autoregulation and function than propofol. IMPLICATIONS: The present study shows that inner ear blood flow is autoregulated under propofol, but not isoflurane, anesthesia during controlled hypotension in humans during middle ear surgery. Further studies are needed to explore the postoperative auditory functional consequences of the choice of the anesthetic drug used in middle ear surgery.

Adult↗
PubMed2003

The effect of hydrogen peroxide applied to the middle ear on inner ear function.

OBJECTIVES/HYPOTHESIS: The objective was to assess the effect of hydrogen peroxide applied to the middle ear on cochlear and vestibular function. STUDY DESIGN: Prospective animal study. METHODS: Sand rats underwent a right-side total labyrinthectomy, and a polyethylene tube was inserted into the left-side middle ear. Following baseline recordings of vestibular evoked potentials in response to linear acceleration stimuli and auditory brainstem response, each experimental animal received five daily applications of hydrogen peroxide into the left-side middle ear. Two control groups received saline and gentamicin, respectively. Subsequently, recordings were repeated and compared with baseline measurements. RESULTS: Saline administration affected neither vestibular evoked potentials nor auditory brainstem response. In contrast, both responses could not be recorded following gentamicin application. After hydrogen peroxide administration, auditory brainstem response could not be recorded in 25% (3 of 12) of the animals, whereas in the remaining nine animals the average auditory brainstem response threshold was significantly elevated by 55 dB (P =.000002). Linear vestibular evoked potentials could not be recorded in 42% (5 of 12) of the animals. CONCLUSION: It appears that topical hydrogen peroxide adversely affects both cochlear and vestibular function of the sand rat. The study demonstrated the effect of a reactive oxygen species on inner ear function and may be useful in the study of mechanisms responsible for this damage and its protection. Clinically, although an animal model was used in the present study, caution should be exercised when large amounts of hydrogen peroxide are applied to a dry, perforated ear.

Administration, Topical↗
PubMed1984

Evacuation of the middle ear by sniffing: a cause of high negative pressure and development of middle ear disease.

Previous research on eustachian tube function has been devoted mainly to the study of the tubal opening ability and pressure equalization. This article summarizes a series of experimental studies focusing on the closing ability of the tube. Results support the belief that the purpose of the tube should be seen primarily as protecting the middle ear from the extensive pressure variations that physiologically take place in the nasopharynx. A number of studies of diseased ears have shown that tubal malfunction was characterized mainly by a reduced ability to withstand negative pressure in the nasopharynx. Sniffing can evacuate the middle ear, causing high negative intratympanic pressure. It seems likely that this mechanism is involved in the development of middle ear effusion and manifest retraction-type middle ear disease.

Child↗
PubMed1987

Reversible changes in inner ear function following hyaluronan application in the middle ear.

A safety study regarding the potential ototoxicity of 1.9% hyaluronan was performed in 20 rats. In all animals the middle ear was completely filled with hyaluronan three times at 2-day intervals between the administrations. Inner ear function was evaluated by computerized auditory brainstem response (ABR) measurements. ABR recordings were performed prior to exposure, after myringotomy (but prior to administration of hyaluronan), 5 days after the last administration (n = 15; these animals were then sacrificed for analysis of the middle ear), one month and 3 months later (n = 5). The hearing thresholds were improved in animals 5 days after the last administration of hyaluronan at 6-8 kHz, whereas the hearing thresholds were impaired at 12 and 20 kHz. After one month, ABR thresholds were even better than precontrol levels at 2, 4 and 6 kHz, whereas at all other frequencies the ABR threshold was normal. Three months after hyaluronan exposure, all ABR thresholds were normal, but viscous material was present in the middle ear in 3 of 5 animals. It is concluded that hyaluronan causes reversible changes in inner ear function but lacks ototoxic adverse effects.

Animals↗
PubMed1989

Survey of interactions between middle ear and inner ear.

Diseases with interaction between the middle ear and inner ear include 1) congenital anomalies, 2) trauma, 3) infection/inflammation, 4) tumors, 5) granulomas, 6) ototoxic eardrops, 7) cochlear implants, 8) otosclerosis, 9) Meniere's disease-decompensated, and Meniere's disease with perilymphatic fistula, and 10) perilymphatic hypertension. Clinical and pathological characteristics are briefly categorized in this survey. The clinical utility of exploratory tympanotomy in diagnosis and treatment of middle ear pathology and middle ear/inner ear interactions is commented upon.

Ear↗
PubMed1992

The evaluation of ear canal, middle ear, temporal bone, and cerebellopontine angle masses in infants, children, and adolescents.

Ear canal, middle ear, temporal bone, and CPA angle masses (except for cholesteatomas) are rare in the pediatric population. The physician needs to have a high degree of suspicion for such lesions if a child presents with ear pain unrelated to infection or otorrhea that fails to improve after treatment. A precise diagnosis needs to be made in these children and also in those with hearing loss, vertigo, and facial paralysis. The most useful imaging procedures for ear, temporal bone, and CPA masses are CT and MR imaging. With a suspected vascular lesion, a definitive diagnosis usually can be made by an imaging procedure or angiography. In all cases of mass lesions, except for some aneurysms and infections, a tissue diagnosis must be secured.

Adolescent↗
PubMed1994

Atmospheric air vs. normal middle ear gas: effects on in vitro growth and collagen synthesis in normal middle ear fibroblasts.

The present study was undertaken to quantitate the effects of atmospheric air and normal middle ear gas on cultured fibroblasts obtained from normal rabbit middle ear mucosa. The cells were exposed to three different gas compositions: 7% O2:5% CO2:88% N2, 21% O2:5% CO2:74% N2, and 75% O2:5% CO2:20% N2. The growth was monitored by measuring the total content of cell protein, the amount of DNA, and the cell division activity. The activity of the synthetic apparatus was determined by the collagen synthesis. For comparison, rabbit skin fibroblasts were grown under identical conditions. The results demonstrated significantly higher replication rate of middle ear fibroblasts at 7% oxygen than at atmospheric air whereas the collagen synthesis was significantly lower at 7%. Furthermore, the responses varied significantly between rabbit middle ear and rabbit skin fibroblasts. Thus the present study substantiates the hypothesis of an influence of atmospheric air on the middle ear mucosa which might be of importance, e.g., in relation to insertion of ventilation tubes or longstanding perforations of the tympanic membrane in otitis media.

Animals↗
PubMed1997

Isolation of human ear specific cDNAs and construction of cDNA libraries from surgically removed small amounts of inner ear tissues.

We have used representational difference analysis (RDA) for subtractive hybridization of oligo dT primed directionally cloned cDNA libraries from human inner ear tissue and a B-lymphoblast cell line. Two rounds of subtraction-amplification, followed by differential hybridization of selected clones led to the isolation of genes which were specific to the ear. Sequence analysis of randomly chosen clones revealed the presence of a histidine rich Ca2+ binding protein, human dynamin, collagen type 1A1, collagen type 2A1, SPARC, human growth hormone, and several specific genes which had no sequence homology in the data base. Furthermore, to apply these techniques for isolating genes specific to distinct inner ear structures and/or cell types of inner ear for which the starting tissue material is limiting, we have used a modified PCR based protocol to construct representative cDNA libraries. We have characterized a cDNA library constructed from small amounts of inner ear tissues recovered by ablative surgical procedure involving labyrinthectomy. The potential application of these protocols for isolating genes involved in hearing and deafness is discussed.

Adult↗
PubMed2007

Do Swiftlets have an ear for echolocation? The functional morphology of Swiftlets' middle ears.

The Oilbird and many Swiftlet species are unique among birds for their ability to echolocate. Echolocaters may benefit from improved hearing sensitivity. Therefore, morphological adaptations to echolocation might be present in echolocating birds' middle ears. We studied the functional morphology of the tympano-ossicular chain of seven specimens of four echolocating Swiftlet species and one specimen each of five non-echolocating species. Three dimensional (3D) reconstructions were made from micro-Computer-Tomographic (muCT) scans. The reconstructions were used in functional morphological analyses and model calculations. A two dimensional (2D) rigid rod model with fixed rotational axes was developed to study footplate output-amplitudes and to describe how changes in the arrangement of the tympano-ossicular chain affect its function. A 3D finite element model was used to predict ossicular-chain movement and to investigate the justification of the 2D approach. No morphological adaptations towards echolocation were found in the middle-ear lever system or in the mass impedance of the middle ear. A wide range of middle-ear configurations result in maximum output-amplitudes and all investigated species are congruent with these predicted best configurations. Echolocation is unlikely to depend on adaptations in the middle ear tympano-ossicular chain.

Animals↗
PubMed1981

Passage of albumin from the middle ear to the inner ear in otitis media in the chinchilla.

A study of the permeability of the middle ear-inner ear interface for macromolecules was carried out in chinchillas with open and obstructed eustachian tubes utilizing tritiated human serum albumin and immunoelectrophoresis. Tritiated albumin was placed in the round window niche area or normal animals and animals in which the eustachian tubes had been obstructed for 24 hours or 14 days. The tritiated albumin was allowed to remain in the middle ear cavity for 24 hours, Samples of middle ear effusion, perilymph, blood and cerebrospinal fluid were collected and measured for radioactivity. Radioactivity was demonstrated in the perilymph. Samples of middle ear effusions and perilymph were also studied by immunoelectrophoresis with goat antihuman albumin. Albumin placed in the round window niche of an experimental animal could be recovered unchanged in the perilymph. The results suggest a pathophysiologic explanation for the association of otitis media and sensorineural hearing loss or endolymphatic hydrops.

Animals↗
PubMed1997

Effect of the middle ear reflex on sound transmission to the inner ear of rat.

The effect of the acoustic middle ear reflex (MER) was quantified using electrodes chronically implanted in the middle ears of rats. Cochlear microphonics (CM) and middle ear muscle EMG were measured under light Ketamin anesthesia after stimulation with tone pulses of 5-20 kHz ranging between 75 and 120 dB SPL. With increasing intensity, the CM measured before the onset of the MER increased to a maximum amplitude and then decreased with higher SPLs. At 10 kHz this maximum was reached at 95 dB SPL, for other stimulus frequencies at higher SPLs. After a latency of 10-20 ms, CM to 10 kHz stimuli of 80-95 dB SPL were decreased by the attenuating action of the MER. The lowest threshold of the MER was also measured at 10 kHz (77 dB SPL in the mean). To stimuli greater than 100 dB SPL after a latency of 6-10 ms, the CM amplitude was increased. That this CM increase to intense stimuli is caused by the action of the MER was confirmed by control experiments such as cutting the tendons of the middle ear muscles. The CM decrease to stimuli below 100 dB SPL, as well as the increase to very intense stimuli, can be explained by sound attenuation caused by the MER, together with the nonlinear dependence of CM amplitude on stimulus level. The observed shift of the maxima of the CM input-output function by the MER to higher stimulus levels probably indicates an increase of the dynamic range of the ear.

Acoustic Stimulation↗
PubMed2006

Surgical reconstruction after subtotal ear resection in malignant melanoma of the ear.

Surgery in malignant melanoma of the external ear often leads to substantial defects where reconstruction poses a difficult challenge. We describe an option of a one-step ear reconstruction after subtotal ear resection in malignant melanoma surgery. In a patient with a high-risk melanoma of the helical rim, a wide local excision was performed. Because of a metastasis-suspect lymph node in the parotid gland, surgery included asservation of the sentinel lymph node, neck dissection and parotidectomy. A complete reconstruction of the ear was achieved using a bilobed flap from the retroauricular and neck region with acceptable cosmetic and functional results by one-step surgery. One micrometastasis was detected in the nuchal region but not in the marked sentinel lymph node. An adequate one-step ear reconstruction as described may also be performed to the benefit of patients with high-risk melanomas, allowing early adjuvant therapy.

Adult↗
PubMed1995

Management of retained ear-rings using an ear block.

A local anaesthetic block of branches of the greater auricular and auriculotemporal nerves was used to facilitate the extraction of retained butterfly backs and ear-ring studs. A total of 28 ear blocks were performed on 26 patients. Two patients required bilateral ear blocks, and 17 earlobes were infected. Complete analgesia was obtained in 25 cases, and two patients complained of tolerable discomfort during removal of the ear-ring. Assessment of analgesia was not possible in one 5-year-old child. We recommend this quick and simple technique for removal of retained ear-rings, particularly when there is associated soft tissue infection, in which case infiltration of local anaesthetic into the earlobe is contraindicated.

Adolescent↗
PubMed1975

Rabbit's ear in cold acclimation studied on the change in ear temperature.

The role of the rabbit's ear in cold acclimation was studied by varying the temperature of a climatic room in the range from -10 to +30 degrees C; The skin temperature in a nonanesthetized rabbit's ear showed a characteristic response to changes in ambient temperatures; plotting the ear temperature against the ambient temperature yielded an S-shaped curve. The mean ambient temperature corresponding to the inflection point on the S-shaped curve shifted significantly from about 13 degrees C to about 8 degrees C after cold acclimated of a group fed for 7 wk at -10 degrees C. The shift of the S-shaped curve after cold acclimation may not be due to the change in the norepinephrine sensitivity of the vascular beds of the ear: the effect of norepinephrine on the pressure-flow curve in the isolated rabbit's ear was almost unchanged between the control and the cold-acclimated groups. It is proposed that the shift of the inflection point gives a qualitative index of the acclimated state of the rabbit at a particular temperature.

Acclimatization↗
PubMed2006

Magnetic nanoparticles: inner ear targeted molecule delivery and middle ear implant.

Superparamagnetic iron oxide nanoparticles (SNP) composed of magnetite (Fe(3)O(4)) were studied preliminarily as vehicles for therapeutic molecule delivery to the inner ear and as a middle ear implant capable of producing biomechanically relevant forces for auditory function. Magnetite SNP were synthesized, then encapsulated in either silica or poly (D,L,-Lactide-co-glycolide) or obtained commercially with coatings of oleic acid or dextran. Permanent magnetic fields generated forces sufficient to pull them across tissue in several round window membrane models (in vitrocell culture, in vivo rat and guinea pig, and human temporal bone) or to embed them in middle ear epithelia. Biocompatibility was investigated by light and electron microscopy, cell culture kinetics, and hair cell survival in organotypic cell culture and no measurable toxicity was found. A sinusoidal magnetic field applied to guinea pigs with SNP implanted in the middle ear resulted in displacements of the middle ear comparable to 90 dB SPL.

Animals↗