Deformities of the external ear associated with middle ear, inner ear, or distant malformations.
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Abnormalities, Multiple↗
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[Formation of the inner ear lymphs. Permeability of inner ear membranes (author's transl)].
1. The endolymphatic system is morphologically a close system. The inner surface of the wall is tightly lined with an epithelium of ectodermal origin. The perilymphatic spaces are enlarged intercellular spaces which are built from the embryonic mesenchyme. 2. The perilymph ist an ultrafiltrate of plasma. There is probably a flow from the cerebrospinal fluid which is constantly renewed. The diffusion in the perilymph is dependent on the concentration and the size of the molecules. The endolymph is mainly a perilymph-filtrate. The "secretory" epithelia (e.g. stria vascularis cells and other tissues) of the endolymphatic system perform an important role to sustain the potassium and sodium concentrations. The ionic concentrations regulate the water movement also the volume of the endolymphatic spaces. They are maintained by anoxy-sensitive pumps. 3. The DC potential within the endolymphatic spaces represents the movement of certain electrical charge through membranes. By applying various inhibitors it is possible to distinguish the pumping mechanisms, and to observe the continuous changes of potassium and sodium concentrations with Na+ specific electrodes and K+ specific electrodes. There are probably three interdependent sources of driving-forces: a. A positively electrogenic K+-pump which is anoxia-sensitive and can be inhibited by Ethacrynic acid. This mechanism is more active in stria cells and less so in utricle and saccule. b. A negatively electrogenic Na+-K+ exchange-pump in all parts of the endolymphatic spaces is inhibited by Ouabain or anoxia. c. The passive diffusion of potassium-ions from endolymph to perilymph results an electro-negative effect.
Animals↗
[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↗
The inner ear of two cynodonts (Reptilia - Therapsida) and some comments on the evolution of the inner ear from pelycosaurs to mammals.
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Animals↗
Effects of middle ear pressure on the inner ear.
It was demonstrated in experiments on normal subjects that moderate ambient pressure changes, creating overpressure in the middle ear, may induce a vestibular reaction. In other experiments on subjects suffering from acute attacks of Meniere's disease, relief of symptoms was achieved by means of ambient pressure changes of the same magnitude.
Ear, Inner↗
Distribution of labeled chloroquine in the inner ear.
Autoradiography of the inner ear was performed at varying intervals following intravenous injection of either chloroquine tagged with carbon 14 (14C), or an iodine 125 (125l)-labeled analogue of chloroquine, in rats. In pigmented rats a strong accumulation and retention was noted in the melanin-bearing tissues. In the inner ear there was a very high concentration in the melanin-containing tissues, eg, the stria vascularis and the planum semilunatum. A strong retention was found in these structures 13 days after injection. Accumulation was not observed in the endolymph nor in the perilymph. No accumulation was found in the inner ear of an albino rat. The ototoxic effects of chloroquine may be caused by an accumulation of the drug in the melanin-containing structures in the inner ear, leading to pathological changes in these tissues and secondary lesions in the receptor cells.
Animals↗
[New animal experiments on aerobic and anareobic inner ear metabolism].
The inner-ear function is bound up with a permanent oxygen supply. The evidence of it are the patterns of the LDH subunits in inner-ear of eight species. The inner-ear energy turnover of glycolysis post-mortem was demonstrated at those species possessing glycogen storages. The MP2 are alterated by perfusion of glucose or iodoacetic acid. During oxygen respiration the MP are not decreased by iodoacetic acid.
Animals↗
[The vessels of the inner ear (author's transl)].
The inner ear as an example of a highly specialized sensory organ also possesses a highly specialized vascularisation. This represents an impressive example for a reasonable adaption of the terminal blood vessels to a specific function of the organ fulfilling more than only the nutrition. In this paper the microvascular bed of the cochlea is examined using both the injection method of the vessels and the biomicroscopic observation in vivo. The combination of these technics supported by histologic and stereoscan microscopic examinations has made it possible to give an account of the functional morphology of the inner ear vessels. As a detailed structural analysis of the vessels morphology with the help of dyes that fill the whole of the vessels space (i.e. Berlin blue) is not possible, perfusion experiments with silver nitrate were performed on the inner ear. After the perfusion the vessels are cleaned again, the silver however imbibes the intercellular reticular substances and after exposure produces a continous and sharp framework of the endothelium and--when present--muscular cells, thus showing the angioarchitectural contours. There is a very clear division of the cochlear vessels in a three dimensional space: The arterial and venous vessels are vividly separated from one another, forming two systems of microvascular units in the lateral wall and the spiral lamina. Each unit begins with special blood vessel convoluts in the modiolus, consisting of loops of arterioles. They are weakly muscularized whereas no muscle structures are seen elsewhere in the other parts of the inner ear vessels. There are no a.-v. anastomoses or sphinkters at all. The function of the vessel loops in the modiolus is to flatten the pulse wave as well as to regulate the blood flow in the microvascular bed by vasomotion. This was proved by statistical examinations of 1200 measurements of the widths of the vessels at several points of the cochlea in a blind study with and without vasoactive drugs. The terminology of the vessels is not standardized. The nomenclature in this paper has regard to the classification of the vessels, the course and the topographic localisation. Silver staining reveals changes in the form of the endothelium cells from the arterial towards the venous end. While the arteries show a long stretched spinle or lancet like form they change over blunt, oval, triangular or rhomboid forms into polygonal cells with spiked border lines at the venules. All experiments together give an account that the blood supply of the inner ear is in close correlation with the blood supply of the brain and too possesses autoregulative mechanisms, which must be localized in the convoluts at the beginning of every microvascular unit of the cochlear vessels.
Arterioles↗
Creatine kinase in epithelium of the inner ear.
Epithelium of the inner ear in the gerbil and mouse was examined immunocytochemically for presence of creatine kinase (CK). Marginal cells of the cochlear stria vascularis and dark cells and transitional cells of the vestibular system were found to contain an abundance of the MM isozyme (MM-CK). CK in these cells concurs with that which is coupled to Na,K-ATPase in other cells and is considered to supply ATP for the Na,K-ATPase that mediates the high KCl of endolymph. Inner hair cells revealed content of the BB isozyme and in this respect resembled the energy-transducing photoreceptor cells in retina. In addition, outer phalangeal (Deiters') cells stained for both MM- and BB-CK whereas inner phalangeal cells evidenced content of only the BB isozyme. Immunolocalization of CK appeared similar in mouse and gerbil inner ear. Specificity of the staining was affirmed by observations in agreement with those reported for CK in various cell types and by staining with antisera from more than one source.
Animals↗
Endolymphatic sac valve implant surgery. II: The unidirectional inner ear valve implant.
A unidirectional inner ear valve implant was developed to direct excess endolymph out of the inner ear in the hydropic state (Ménière's disease) into the mastoid cavity. A detailed technical description of the valve implant is presented as well as some technical aspects of the valve implant based on the surgical anatomy of the endolymphatic sac.
Ear, Inner↗
[The activity and capacity of the inner ear (author's transl)].
The inner ear is an energy converter and a biochemical amplifier. The normal function of the stria vascularis and the organ of Corti is bound exclusively to the respiratory metabolism. Some but not all species are equiped by a glycolytic reserve metabolism for preservation of the sensory cells, as could be improved in amplitude-time-curves of cochlea microphonics in hypoxic conditiones. A promising therapy of inner ear disturbances following short timed oxygen deficiency depends on the moment of the treatment.
Animals↗
Experimental alteration of physiological state of inner ear fluids.
Mechanisms of endolymphatic hydrops formation in the inner ear are not yet fully understood. The available knowledge of the composition and the function of inner ear fluids, of mechanisms for maintenance of microhomeostasis, and the possible factors responsible for hydrops formation were reviewed. The nature of the functional barrier systems of the inner ear was investigated by measuring the amount of intravenously or intracisternally injected test substances which entered the perilymph. Based on studies of the osmotic relationship between the blood and the perilymph, an hypothesis of hydrops formation is proposed. The hypothesis predicts an osmotic imbalance, resulting from an upset of the homeostasis between the fluid compartments and the tissues of the inner ear, as a factor responsible for endolymphatic hydrops formation. An osmotic imbalance can be induced by various experimental conditions including metabolic disorders. The results of animal experiments strongly suggest the necessity of further survey of metabolic imbalance in Ménière's patients.
Adenosine Triphosphatases↗
A single-nucleus transcriptomic atlas of human inner ear development.
Hearing and balance rely on coordinated activity of multiple inner ear cell types, yet the mechanisms governing their development and specification in humans remain unclear. Consequently, this limits our understanding of how disease genes affect cell type formation and function, limiting the development of targeted treatments, including gene therapies. Here we present the Human Inner Ear Development snRNA-seq Atlas (HIEDRA), a single-nucleus transcriptomic atlas of the human inner ear spanning the first and second trimesters. HIEDRA maps sensory and nonsensory epithelia, neurons and mesenchyme-associated populations, including undercharacterized secretory cells required for ion homeostasis. We identify selective vulnerability in sensory and secretory lineages to disease-associated genes, infer regulatory networks and show that Hedgehog signaling suppression is required for secretory cell specification. We validate this mechanism in human inner ear organoids, expanding the model to include all major cell types. Altogether, these findings provide insights into human inner ear cell type specification, improve in vitro models and establish HIEDRA as a resource for investigating human inner ear development.
Journal Article↗
Oxygen transport to the inner ear.
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Animals↗
Inner ear hemorrhage and endolymphatic hydrops in a leukemic patient with sudden hearing loss.
Several significant histopathological findings were noted in a case of sudden hearing loss in a patient with chronic lymphocytic leukemia. The major pathological findings were leukemic hemorrhage into both perilymphatic and endolymphatic spaces in the cochlear and vestibular systems, endolymphatic hydrops in the cochlea and sacculus, and a relatively narrowed and straightened vestibular aqueduct and endolymphatic sac. Additional interesting findings include: loss of hair cells in the organ of Corti and vestibular end-organs; destruction of the stria vascularis (possibly the origin of the blood); fibrosis in the perilymphatic spaces in the cochlea and the vestibule, and in the endolymphatic space in the vestibule; and new bone formation in the perilymphatic spaces in the vestibule. The leukemic infiltrate observed in both the cochlea and the vestibule was not considered to be significant. Hemorrhage into the cochlea is thought to be the most reasonable cause of the sudden hearing loss in this case. Also discussed are fibrosis and osteogenesis as a late consequence of hemorrhage, and the coexistence of endolymphatic hydrops with an anomaly of the vestibular aqueduct and endolymphatic sac.
Aged↗
Inner ear morphology in Down's syndrome.
A comparative study was made on four pairs of temporal bones from patients with Down's syndrome (trisomy 21) and 15 pairs of temporal bones from other infants of the same age range. Spiral reconstructions showed chochlear length to be slightly shorter in temporal bones from patients with Down's syndrome than that in the controls. Based upon these dimensional measurements, a developmental anomaly of the vestibular apparatus was found.
Cochlea↗
[Middle and inner ear barotrauma caused by scubadiving (author's transl)].
On the basis of our own experiences and the current literature, the following guidelines were established for the evaluation of scubadivers: 1. The ENT physical examination must include otoscopy and the valsalva manoeuver. The scubadiver should be able to promptly and symmetrically inflate his middle ear spaces. A central perforation is a relative contraindication, while a marginal ear drum perforation is an absolute contraindication for scubadiving. 2. Recommendations to the diver: Ear pressure equalibration should be performed continuously with increasing and decreasing water depth. Ear plugs should never be used. 3. Management of diving injuries: Barotitis should be treated in a manner similar to acute otitis media. Transient vertigo while ascending (alternobaric vertigo) without nystagmus or hearing impairment needs no further vestibular examination. A middle ear exploration is indicated when there is suspicion of a perilymphatic fistula.
Barotrauma↗
[The penetration of tympanally applied tetracycline in the inner ear (author's transl)].
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Animals↗