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At least 415 records · Page 23Linked to original sources
PubMed1995

Selection of biomaterials for middle and inner ear implants.

In the selection of biomaterials for middle ear applications of implantable devices, certainly the site of implantation and the mass of the implant will dictate the choice of biomaterials. Hermetic sealing of an implant is best achieved by the use of metals, not polymers. Osteocompatibility of an ossicular implant can be enhanced by the incorporation of calcium phosphates such as hydroxyapatite coatings. Finally, osseointegration or osseofixation is neither necessary nor desirable for ossicular implants, because (1) they may need to be removed or replaced in the future and (2) their solid fixation to an ossicle is not necessary for the vibratory function of hearing amplification.

Biocompatible Materials↗
PubMed2002

[Changes in plasma inner ear hormones after endolymphatic sac drainage and steroid-instillation surgery (EDSS)].

We treated 33 cases of intractable Meniere's disease with endolymphatic sac drainage and steroid-instillation surgery (EDSS), attaining good long-term results in vertigo and hearing. To elucidate how EDSS affects the diseased inner ear, we examined changes in plasma inner ear hormones after EDSS. Among inner ear hormones, plasma vasopressin was significantly decreased after EDSS compared to after mastoidectomy. In cases with good long-term results in vertigo and hearing, postoperative plasma vasopressin remained lower over the long term than in cases with poor results. In cases with negative glycerol test results one year after surgery, postoperative plasma vasopressin also remained significantly lower over the long term than in cases with positive results. Previous studies reported that vestibular neurons projected into hypothalamic supraoptic and paraventricular nuclei and that changes in the inner ear pressure were related to plasma vasopressin. Taken together with present findings, this suggests that EDSS may reduce plasma vasopressin through modification of the diseased inner ear environment, resulting in improved inner ear function.

Aldosterone↗
PubMed1995

Three-dimensional MR of the inner ear with steady-state free precession.

PURPOSE: To describe the steady-state free-precession MR sequence and its application to the study of the inner ear. METHOD: The inner ear was imaged with CT and a 0.5-T MR unit in three dimension, to evaluate the various signals from the lumen of the labyrinth. RESULTS: Normally, the signal from the perilymphatic and endolymphatic spaces is homogeneous. However, among our cases of neurosensory deafness, differences of signal and morphology were seen in patients with otosclerosis, ossifying labyrinthitis, and inner ear malformations. CONCLUSION: Three-dimensional MR, used together with routine two-dimensional fast spin-echo, is another diagnostic too]l that can provide new data in the evaluation of the normal and unhealthy inner ear.

Cochlea↗
PubMed1985

Appearance of H and B antigens in primary sensory cells of the rat olfactory apparatus and inner ear.

In the rat olfactory apparatus and inner ear the H antigen was first detected at the 15th day of gestational age. The B antigen appeared at the 16th day. In the olfactory apparatus H and B antigens were first detected in cells of the olfactory mucosa and of the olfactory bulb primordium. Towards the 16th and 17th days many small positive cells were seen between these two areas. In newborn and adult rats, olfactory bulb H and B antigens were restricted to the processes of the peripheral primary sensory cells. Both H and B antigens were detected in the epithelium of the inner ear and were later concentrated in the hair cells of the organ of Corti, the utricle and the saccule.

ABO Blood-Group System↗
PubMed2004

Characterization of leukocyte subtypes in chicken inner ear sensory epithelia.

Human hearing and balance require intact inner ear sensory hair cells, which transduce mechanical stimuli into electrical signals that are transmitted to the brain. Loss of hair cells after birth in mammals is irreversible, whereas birds are able to regenerate hair cells after insult and demonstrate ongoing hair cell production in the vestibular epithelia. Leukocytes reside in undamaged sensory epithelia of the avian inner ear and increase in number after trauma, prior to the proliferation of hair cell progenitors. It has been hypothesized that leukocyte-produced growth factors or cytokines may be involved in triggering hair cell regeneration. Little is known about the specific leukocyte subtypes present in avian ear. Immunohistochemistry with a panel of monoclonal antibodies to chicken leukocytes was used to identify leukocyte subtypes in normal posthatch chicken ear sensory epithelia. The responsiveness of the leukocytes to aminoglycoside-induced damage was also observed. Based on immunocytochemical and morphological criteria, we quantified leukocyte subtypes in normal and drug-damaged auditory and vestibular sensory epithelia. Data indicate that lymphocytes (B and T cells) do not reside in normal or drug-damaged ear sensory epithelia at 1-3 days post insult but are present in adjacent nonsensory tissues. The most common leukocytes in inner ear sensory epithelia are ramified cells of the myeloid lineage. Many of these are MHC class II positive, and a small percentage are mature tissue macrophages. An absence of leukocytes in lesioned areas of the auditory sensory epithelium suggests they may not play a critical role in triggering hair cell regeneration.

Age Factors↗
PubMed2000

[A novel method for screening anti-inner ear autoantibody in patients with autoimmune diseases].

OBJECTIVE: To appraise the clinical value of a newly established method, rapid electric field immobilizing liquid phase molecule dot blot analysis (REILMD), for screening anti-inner ear autoantibody in patients with autoimmune diseases. METHODS: Seventy-one patients with 11 kinds of autoimmune diseases were chosen for the study. Both the general immunity and autoantibodies were tested. In the processes of detection of anti-inner ear autoantibody, REILMD was used for screening, and then the Western blot was used to define the molecular weight of inner ear antigen recognized by the positive autoantibody. RESULTS: Acceleration of erythrocyte sedimentation rate (ES), positive rheumatoid factor (RF), increases in C reactive protein (CRP), IgG and circulating immune complex (CIC) were found in most cases with rheumatoid arthritis (RA) and systemic lupus erythematodes (SLE). Some of these patients had increased IgA, IgM and C4. Two of 16 RA had anti-double-stranded DNA (dsDNA) and anti-mitochondria and 4/16 had anti-nucleus antibodies. Eleven of 16 SLE had antinucleus, 7/13 had anti-ribonucleoprotein (RNP), anti-Sjögren syndrome A (SSA) and anti-dsDNA, 3/13 had anti-smooth muscle (Sm) and 1/13 had anti-DNA topoisomerase I (Scl)-70, striated muscle and stomach acid cell antibodies. No autoantibody was detected in AS. Anti-inner ear autoantibody existed in 9 out of 71 patients (13%) with autoimmune diseases, in 2 of 21 patients (10%) with sudden deafness and only in 1 of 48 control subjects (2%, coronary heart disease). The anti-inner ear autoantibody was positive in 5 of 16 (31%) patients with SLE and 1 each in RA, AS, Behset's disease and streptococcus infection syndrome. In patients with positive anti-inner ear antibody, 67% had anti-nucleus antibody, 50% had anti-RNP and dsDNA antibody. The molecules recognized by the positive anti-inner ear antibody were defined as 52,000, 36,000, 31,000 and 15,000 molecules of inner ear antigen. CONCLUSION: REILMD is a feasible and easy method for screening anti-inner ear autoantibody. Several autoimmune diseases, particularly SLE, may be implicated in damage to the inner ear.

Adolescent↗
PubMed2004

Expression patterns of claudins, tight junction adhesion molecules, in the inner ear.

Tight junctions (TJs) are indispensable for the establishment of compositionally distinct fluid compartments in the inner ear, but our knowledge of the claudins, TJ adhesion molecules, in the inner ear is still fragmentary. We examined the expression and distribution of claudin-1 to claudin-18 (except for claudin-7, -13 and -17) in the inner ear by immunofluorescence microscopy. In the cochlea, the organ of Corti expressed claudin-1, -2, -3, -9, -10, -12, -14 and -18. In the stria vascularis, claudin-1, -2, -3, -8, -9, -10, -12, -14 and -18 were expressed in the marginal cells, whereas the basal cells were positive only for claudin-11. In Reissner's membrane and the spiral limbus, the expression of claudin-1, -2, -3, -8, -9, -10, -12, -14 and -18 was detected. Furthermore, in the vestibule, claudin-1, -3, -9, -12, -14 and -18 were expressed in the sensory epithelia, whereas in the dark cell area claudin-1, -3, -8, -9, -12, -14 and -18 were detectable. These findings, i.e., very complex expression patterns of claudin species in the inner ear, would reflect the importance and the complexity of the barrier function of TJs in the inner ear.

Animals↗
PubMed2005

Sox2 is required for sensory organ development in the mammalian inner ear.

Sensory hair cells and their associated non-sensory supporting cells in the inner ear are fundamental for hearing and balance. They arise from a common progenitor, but little is known about the molecular events specifying this cell lineage. We recently identified two allelic mouse mutants, light coat and circling (Lcc) and yellow submarine (Ysb), that show hearing and balance impairment. Lcc/Lcc mice are completely deaf, whereas Ysb/Ysb mice are severely hearing impaired. We report here that inner ears of Lcc/Lcc mice fail to establish a prosensory domain and neither hair cells nor supporting cells differentiate, resulting in a severe inner ear malformation, whereas the sensory epithelium of Ysb/Ysb mice shows abnormal development with disorganized and fewer hair cells. These phenotypes are due to the absence (in Lcc mutants) or reduced expression (in Ysb mutants) of the transcription factor SOX2, specifically within the developing inner ear. SOX2 continues to be expressed in the inner ears of mice lacking Math1 (also known as Atoh1 and HATH1), a gene essential for hair cell differentiation, whereas Math1 expression is absent in Lcc mutants, suggesting that Sox2 acts upstream of Math1.

Alleles↗
PubMed2004

[1D-and 3D- computer simulation for experimental planning and interpretation of pharmacokinetic studies in the inner ear after local drug delivery].

The local delivery of drugs to the cochlea is a promising alternative to systemic treatment of inner ear disorders. Whilst new drugs are being developed for this purpose, it is important to determine the time course and total dose required for the various target regions within the inner ear. Due to the small fluid spaces of the inner ear and the resulting experimental and analytical difficulties, many animal studies have only obtained one sample per animal. This results in limited information about drug time courses at specific locations in the inner ear. We show here how computer models considering general pharmacokinetic principles and inner ear geometry are used for application of the 3R-principle in animal research while avoiding experimental sampling artefacts. This can be achieved by: (1) careful planning and interpretation of experiments to study pharmacokinetics in the inner ear, (2) optimising volume sampling techniques, (3) facilitating the use of advantageous, continuous sampling methods like microdialysis and (4) developing a 3D-model that will permit consideration of the complex geometry of the inner ear when transferring results from one species to another.

Animal Testing Alternatives↗