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At least 397 records · Page 22Linked to original sources
PubMed2000

[Evaluation of the effect of streptomycin perfusion of the labyrinth in the treatment of Meniere's disease and endolymphatic hydrops].

OBJECTIVE: To investigate the clinical effect of streptomycin perfusion of the labyrinth (SPL) in the treatment of Meniere's disease. METHOD: 13 patients with Meniere's disease and 3 patients with delayed endolymphatic hydrops (DEH) underwent SPL. The follow-up time was between 5 and 7 years (average 6.3 years). RESULT: Vertigo was completely controlled in 9 patients, substantialy controlled in 4, limitedly controlled in 2 and not controlled in 1. Hearing was improved in 1 patients, stabilized in 5 and worse in 10. Tinnitus was improved in 3 patients, stabilized in 5 and worse in 8. CONCLUSION: SPL is a safe and effective method in the treatment of Meniere's disease and DEH, but the hearing may be insulted and tinnitus may be worse in some patients.

Adult↗
PubMed2003

Pharmacologic manipulation of the labyrinth with novel and traditional agents delivered to the inner ear.

We describe the methodology and rationale behind the delivery of therapeutic medicines to the inner ear. The inner ear has long been impervious to pharmacologic manipulation. This is most likely the result of a protective mechanism called the blood-labyrinth barrier, whose function closely resembles that of the blood-brain barrier. This protective barrier impedes the clinician's ability to treat inner ear diseases with systemically administered medications. Since 1935, otolaryngologists have attempted to manipulate the inner ear with trans-tympanically injected medicines. Success has varied widely, but medicinal ablation of vestibular function can be achieved in this manner. Unfortunately, the auditory system is also at great risk from any medicine that is delivered to the inner ear via the middle ear. Over the past 10 years, significant improvements in drug delivery have allowed for more "titratable" treatment, which has reduced (but not eliminated) the risk of permanent hearing loss. In this article, we discuss both novel and time-tested methods of delivering medicines to the inner ear. We also review the classes of medications that alter inner ear function and the attendant risks of such treatments.

Aminoglycosides↗
PubMedDate not supplied

[Radiologic anatomy of the labyrinth artery].

Carotid and vertebral angiographic investigations were performed to study x-ray anatomy of the artery of the labyrinth (AL) in 96 inpatients admitted to the N. F. Sklifosovsky emergency care clinic. According to the angiograms, AL originated from the distal parts of the inferior anterior cerebellar artery in 66.3% of the patients. In this case it has a straight form. When initiating from the proximal parts of the basilar artery (33.7% of the patients), AL was shorter (0.8 +/- 0.3 against 2.5 +/- 0.8 cm) and curved. In any case AL was situated along the upper edge of the pyramid before it entered the internal acoustic meatus. By the meatus or inside it AL forms a characteristic loop or semiloop. A complete AL left-right symmetry was observed in 61.8% of the cases.

Adolescent↗
PubMed1976

[Aequidensitometrie of the labyrinthic capsule with special regard of the bottom of the internal auditory meatus].

It has been proved by densitometry that the thickness of the separating wall between the basal coil and the fundus of the internal auditory meastus as well as the thickness of the labyrinthic wall increase with age. The mineral contents is simultaneously reduced. The diameter of the cochlear canal is also reduced with age. These facts have been demonstrated by aequidensitometry and by summation color pictures of aequidensites.

Adolescent↗
PubMed2003

The foetal development of the human osseous labyrinth in a computed tomographic study.

A CT study was performed on 8 foetuses aged between 20 and 38 weeks. In foetuses at the 20th week the semicircular canals, the spiral canal of the cochlea and the initial (labyrinthine) part of the facial canal are visible. At week 24 the tympanic part of the facial canal is observed. In the 31st week the cochlea is divided into 2 compartments, and in the 38th week the vestibular aqueduct and osseous labyrinth are seen.

Body Patterning↗
PubMed2001

Blood-labyrinth barrier and fluid dynamics of the inner ear.

Under normal conditions, the inner ear possesses remarkably stable homeostatic mechanisms for the maintenance of functional integrity of the inner ear fluid. The inner ear fluid maintains its homeostasis by a variety of regulatory mechanisms such as an ion transport system, a blood-labyrinth barrier, and a constant blood supply. Highly regulated transport of ions into and out of the inner ear provides for the maintenance of inner ear fluid composition necessary for auditory transduction. Any disturbance in one of these mechanisms can disrupt homeostasis expressed by ionic, osmotic, or metabolic imbalance between the compartments. Free radicals, stress hormones, noise exposure, and aminoglycoside antibiotics may induce short- and long-term effects on cellular function of the auditory or vestibular system (or both) and serve as a triggering mechanism for abrupt functional disturbances of inner ear fluid ion homeostasis. In this article, we present a comprehensive review of the mechanisms underlying inner ear fluid homeostasis necessary for normal auditory function and factors that can disrupt homeostasis and lead to functional disturbances, namely sensorineural hearing loss, tinnitus, and vertigo.

Blood↗
PubMed1992

[Solute movement across the round window membrane in comparison with that across the blood-labyrinth barrier].

The permeability of the normal round window membrane of the guinea pig to trimethylphenylammonium (TMPA) was assessed using ion-selective electrodes and compared with the rate of TMPA entry from the systemic blood circulation into the scala tympani (ST) of the cochlea across the so-called blood-labyrinth barrier. While the round window niche was irrigated with artificial perilymph containing 1 mM TMPA, the TMPA concentration in ST of the basal turn rose rapidly so as to reach 20-50% of the irrigating medium concentration in one hour. Following this procedure, the concentration declined significantly faster when the niche was subsequently irrigated with TMPA-free artificial perilymph than when the niche was left free of any fluid. This result shows that the membrane is fairly permeable to TMPA in both directions. Furthermore, TMPA entry from blood to STs of the basal and third turns was observed while the plasma TMPA concentration was maintained at about 0.5 mM by continuous intravenous infusion of isotonic 50 mM TMPA medium (1 part 150 mM TMPA + 2 parts lactated Ringer solution). TMPA appeared to distribute evenly from the blood to both turns at a much slower rate than across the round window membrane. In another experiment, the round window niche was irrigated with TMPA-free artificial perilymph during the intravenous infusion of 50 mM TMPA medium. The TMPA concentration increase in ST of the basal turn was greatly suppressed, whereas that of the third turn was not affected for at least an hour.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

The structure and development of the 'plana semilunata' of the labyrinth of the trout.

Five plana semilunata consisting of tall epithelial cells were found in the semicircular canal ampullae of the trout labyrinth. All these areas began to develop after hatching. Their cells were cuboid at fry stages and prismatic in juveniles and adults. Cell outlines were smooth, with no basal infoldings of the plasma membrane or apical microvilli. The cell nucleus occupied basal locations in juveniles but migrated centrally in adults. The most conspicuous organelle, the smooth endoplasmic reticulum, was continuous with a well-developed vacuolar system. These cells stored numerous glycogen granules. The ultrastructural features of the plana semilunata strongly suggest their involvement in endolymph secretion.

Animals↗
PubMed2004

[Influence of the cerebellum on the postural labyrinth reflex--experimental and clinical data].

The subject of the study was to estimate the influence of the cerebellum and the postural labyrinth reflex. The pigeons after hemicerebellectomy or vermis ablation this reflex was analysed during body rotation around sagittal and transversal axis. In the clinical part of observations, stabilometric measure of head motion during balance on the movable platform was performed in patients with supratentorial and cerebellar tumors. The results showed the greatest reflex disturbances in vermis ablation and vermis tumors. In hemispheric tumors of the cerebellum these disorders were slighter, but greater in comparison with supratentorial lesions. The authors stressed the role of the vermis in controlling of the reflex.

Adult↗
PubMedDate not supplied

High signal from the otic labyrinth on unenhanced magnetic resonance imaging.

High signal from the otic labyrinth was observed on precontrast MR scan of two patients who presented with sudden hearing loss and vertigo. The authors suggest the possibility that the high signal was caused by hemorrhage but that clinical significance and therapeutic implications of this finding need further study.

Adult↗
PubMed1991

[Statistical analysis of mediator release from the cyto-neural junction of the posterior canal of the labyrinth isolated from the frog].

The transmitter release mechanism was investigated at the cyto-neural junction of the frog labyrinth posterior canal. Low frequency (less than 100/s) non overlapping EPSPs were intracellularly recorded both at rest and during inhibitory mechanical stimulation of the canal (2-8 deg/s2). Recordings were obtained: in control solution; in the presence of increased external Ca2+ (9 mM); in Ca-free EGTA (5 mM) solution and during electrical activation at 50 Hz of the posterior canal inhibitory efferent system. Individual synaptic potentials were digitized and their peak amplitudes, their time integrals as well as the time intervals between them were evaluated. The time intervals proved to be exponentially distributed, suggesting a random EPSP occurrence. The analytical reconstruction of the EPSP waveform indicated that a gamma- function fitted reasonably well both the single and averaged events. As regards the averaged event, despite the scatter in the values of the gamma-function exponential factor (range 1.1-2.2), in the EPSP time-to-peak (0.6-1.2 ms) and peak amplitude (0.9-2.7 mV) displayed by the units, no significant differences were observed in the same fibre between control and test conditions. Moreover, the event peak amplitude distribution represented by cumulative plots or amplitude histograms was fitted by a lognormal function. The distributions obtained for the same unit in control solution proved to be not significantly different from those successively obtained under test conditions. The unimodal and continuous EPSP distributions, together with the unvarying characteristics of the single events, strongly suggest that the observed potentials are true mEPSPs due to the release of single quanta of transmitter.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMedDate not supplied

[Comparative study of the effects of melatonin and epitalon on the protracted memory under the shuttle labyrinth test conditions in rats in the course of aging].

The influence of the chronic administration of melatonin (epiphyseal hormone) and epitalon (a synthetic tetrapeptide increasing melatonin production) on the learning process and the protracted memory has been studied in LIO rats in the course of aging for 2 years under standard illumination regime (12L :12D). The daily administration of melatonin (Sigma, USA) with drinking water (in 10 mg/liter dose at night) in rats beginning with the age of 4 months did not influence the learning processes in young and adult animals but it was found to contribute to optimization of the brain cognitive function in rats in the course of aging, by improving the protracted memory process. Epitalon administered in a daily dose of 0.1 microg per animal beginning with the age of 4 months showed mnemotropic properties (decreasing the extent of memory disorders) in old rats under conditions of the shuttle labyrinth test.

Age Factors↗
PubMed1991

Partitioning of the labyrinth: application in benign paroxysmal positional vertigo.

Partitioning of the labyrinth is a new laser technique that creates a fibrous band within the inner ear. The application of this technique to benign paroxysmal positional vertigo (BPPV) is described in the first two patients to undergo this procedure. The partitioning technique involves blue-lining the posterior semicircular canal near its ampulla and lasing the blue-lined area. The technique provides a prompt decrease and the ultimate elimination of BPPV. There is some mild motion sensitivity of 6 to 8 weeks duration, and some transient (3-week) sensorineural hearing loss. The use of immediate postoperative low dose steroids provides marked decrease in the motion sensitivity and elimination of the transient sensorineural hearing loss. Lasing two adjacent areas on the posterior semicircular canal may prevent transient recurrence of the positional vertigo during the healing process.

Adult↗
PubMed1991

[Malformations of the bony labyrinth and deafness].

17 new cases of malformation of the bony labyrinth detected radiologically (tomography, CT) and associated with perceptive or composite deafness are reported. 2 cases discovered in spontaneous or traumatic recurrent meningitis are described, as well as 1 case discovered after the occurrence of total deafness following stapedial surgery. The malformations were unilateral in 7 cases, bilateral in 10. Deafness was of the composite type in 6 cases. An associated malformation of the middle or external ear was noted in 4 cases. 5 cases were included in a context of multiple malformations, including 1 case of otobranchiorenal syndrome, 1 case of Apert's syndrome and 3 cases of craniostenosis. Referring to the classification given by Mrs Vignaud and Jardin, we have encountered 1 case of stage I malformation, 9 cases of stage II, pseudo-Mondini malformation, 1 case of stage III or true Mondini malformation, 1 case of stage IV malformation, 3 cases of malformation of the aqueduct of the vestibule, ie. stage V. We have also encountered 2 isolate cases of stenosis of the internal auditory canal. On the basis of these cases, we report a few physiopathogenetic hypotheses and various classifications currently described in the literature. We also list the various associated external and middle ear malformations and the multiple-malformation syndromes that are commonly described. Stress is laid on the fact that these malformations often go undetected in congenital deafness, as well as on the usual course of these types of deafness for which there is no medical or surgical treatment.

Abnormalities, Multiple↗
PubMed1976

The phases of sleep and wakefulness after bilateral labyrinth destruction in chronic cats.

After bilateral destruction of the labyrinths, the duration of paradoxical sleep increased from 4% in the intact animals to 8% after destruction. This increase was the result of an increase from 2.2 to 2.6 in the average number of epiodes of paradoxical sleep as well as of an increase from 3.2 to 5.5 min of the duration of each episode of paradoxical sleep. One latency of the first appearance of an episode was shortened, from the 77th min at the beginning of registration to the 43rd min after destruction. During this time the duration of wakefulness decreased from 30% to 17%.

Animals↗
PubMed1990

[Inhibition and efferent facilitation of sensory activity in the isolated labyrinth of the frog].

The functioning modalities of the efferent system were analysed in the isolated frog labyrinth. The efferent synapses of the posterior canal were activated via an axon reflex by antidromic electrical shocks (10-200 Hz) applied for increasing times (250 ms-10 s) to the anterior-horizontal nerves. Either decrease (inhibition) or increase (facilitation) in the resting discharge rate were observed in the majority of the units examined. Inhibition and facilitation, however, are peculiar to any given unit since inhibition does not reverse to facilitation or vice-versa. This fact as well as the long response latency (not less than 10 ms) and the linear dependence of both effects on the stimulation frequency suggest that inhibition and facilitation are due to the repetitive activation of two different types of efferent fibres synapsing on the hair cells. The drastic modifications in the afferent synaptic discharge produced by full activation of the efferent system indicate that the static properties (response asymmetry) as well as the dynamic properties (response adaptation) of the mechanically driven afferent response can be substantially controlled by the central nervous system at the receptor level.

Action Potentials↗
PubMed1989

[High extracellular concentrations of potassium and rubidium modulate the synaptic transmission in the frog labyrinth].

High extracellular K or Rb levels (20 mM) produce an increase in the resting EPSP and spike frequencies recorded intra cellularly from single fibres of the posterior nerve in the isolated frog labyrinth. The afferent discharge facilitation proved to be inversely related to the fibre's initial resting activity. The K effect is systematically larger than the Rb effect. High sensitive and scarcely sensitive units may be identified with respect to K and Rb action. The present findings suggest that, according to previous models of hair cell functioning, the K and Rb effects are mediated by a raise in intracellular Ca concentration which sustains an increased transmitter release at the cyto-neural junction.

Action Potentials↗