[Cerebrospinal otorrhea following opening of the labyrinthine windows due to hydraulic pressure].
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Adult↗
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Results for “Labyrinthine Fluids”
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[Spontaneous csf fistulas in otorhinolaryngology (apropos of 4 cases, one of which is a double fistula, ethmoidal and labyrinthine)].
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Adult↗
[Receptor current in ciliate cells of the frog sacculus].
The present study aims to provide further contribution towards identifying the ions which actually sustain the receptor current in labyrinthine sensory cells. The experiments were carried out on isolated sacculi of the frog. The macular epithelium of the sacculus was positioned in a two compartment chamber which allows the fluid bathing the inside and the outside of the sacculus to be replaced separately with solutions having different ionic composition. The potential across the epithelium was clamped to zero and both the receptor current and the postsynaptic potentials in response to mechanical stimuli were first recorded when the endolymphatic fluid had a normal ionic composition and then, at different time intervals, after replacing the endolymph with solutions deprived of K+ (replaced with Na+, Rb+, Cs+ and Ca++) and Na+ (replaced with choline and saccharose). The results have shown that both the receptor current and the postsynaptic potentials are abolished after replacing the endolymphatic K+ with Na+, Cs+ or Ca++, whereas are partially preserved when K+ is replaced with Rb+. These findings strongly suggest that the receptor current in labyrinthine sensory cells is carried almost exclusively by K+ and that this current flows across specific K-channels.
Action Potentials↗
The pharmacological treatment of Menière's disease.
The management of Menière's disease often provides a formidable clinical challenge largely because its precise aetiology is unknown. There is no known 'cure' once the condition is established, but drugs may be helpful in treating both the acute attacks of vertigo, and in more long-term management, particularly in the earlier fluctuant stage. These remedies are largely symptomatic and there are few if any properly controlled studies of their efficacy. Suppressant drugs may act centrally at neurotransmitter sites, or peripherally on the labyrinth. Conventional diuretics and osmotically acting agents have been given to reduce the endolymph fluid volume. Histamine analogues directly reduce inner ear fluid pressure mainly by increasing the cochlear blood flow, and are probably the treatment of choice. Otovestibulotoxic drugs given systemically to cause chemical labyrinthine ablation are frequently effective in abolishing attacks of vertigo but often resulted in disabling oscillopsia and ataxia. There is now evidence that local administration by intratympanic injection may well be more efficacious resulting in selective partial end organ ablation. To date innovative immune modifying regimes have not proved helpful.
Aminoglycosides↗
Congenital cerebrospinal fluid fistulae of the petrous temporal bone.
Spontaneous cerebrospinal fluid fistulae from the subarachnoid space into the middle ear cavity may be classified as perilabyrinthine or translabyrinthine. The very rare perilabyrinthine group, through bony defects close to but not involving the labyrinth, usually have normal hearing initially. The commoner translabyrinthine group are nearly always associated with anacusis, severe labyrinthine dysplasia and a route via the internal auditory meatus. The labyrinthine deformity is more severe than the type classically described by Mondini, and evidence of a dilated cochlear aqueduct in these cases is also unconvincing.
Cerebrospinal Fluid Otorrhea↗
Management of traumatic facial nerve paralysis with carotid artery cavernous sinus fistula.
Massive skull base injuries require detailed preoperative neurological and neurovascular assessment prior to undertaking surgical repair of isolated cranial nerve deficits. We present the management of a patient with traumatic facial paralysis, cerebrospinal fluid leak, and carotid artery cavernous sinus fistula as the result of a gunshot wound to the skull base. The carotid artery cavernous sinus fistula was ultimately controlled with super-selective embolization via the vertebral artery. The facial nerve injury was then safely treated with mobilization of the labyrinthine and vertical segments to allow a primary anastomosis.
Adult↗
Microarchitecture of the cat testis with special reference to Leydig cells: a three-dimensional study by alkali maceration method and scanning electron microscopy.
Testes from adult cats were studied by means of parallel transmission and scanning electron microscopy (SEM) after NaOH digestion technique, which selectively removed connective tissues or cells. The testis is covered by a dense fibroconnective tunica albuginea that partially divides the organ in lobules by sending septa into the parenchyma. The lamina propria of the seminiferous tubules consisted of one or two rows of cells. The interstitium was made up of randomly arranged collagen bundles. The most significant feature was the numerous Leydig cells rich in lipid droplets and displaying epithelioid features. Following alkali digestion and SEM these cells showed a cord-like arrangement. The cords were formed by one or two closely apposed cells, in between which some labyrinthine or canalicular-like spaces were left that in some areas opened in wide perivascular spaces. This particular arrangement of Leydig cells and the labyrinthine intercellular spaces is very likely designed to improve cell secretion of hormones, facilitating their transport into the blood, as well as the traffic of fluids and metabolites. The present techniques allowed the visualization of a real three-dimensional testicular microarchitecture and microtopography, not detectable with other methods. Such a study may help to better highlight the testicular morphophysiology.
Animals↗
Low frequency air-bone gap in Menière's disease without middle ear pathology. A preliminary report.
The audiograms of some patients suffering from Meniere's disease show an unexplained conductive component, or air-bone gap (ABG), predominantly in the low frequencies. Neither the history nor physical findings support poor eustachian tube function, ossicular chain abnormalities, chronic ear disease, physical trauma, or otosclerosis as a cause of this audiometric finding. In the present study, 40 patients diagnosed as suffering from classical Meniere's disease were evaluated audiometrically. Thirteen (32.5%) of these patients demonstrated a low frequency ABG. An otologic evaluation was performed on each patient who exhibited the abnormal finding, but no middle ear pathology was discovered. An otherwise unexplained low frequency ABG in patients with Meniere's disease suggests the possibility of an "inner ear" conductive hearing loss. This conductive component may result from endolymphatic hydrops or perilymphatic hypertension (i.e., an inner ear hyperpressure exerted against the medial surface of the stapedial footplate) rather than from middle ear pathology. "Inner ear" conductive hearing loss is thought to be caused by an increase in inner ear fluid volume (endolymphatic hydrops) and pressure (endolymphatic or perilymphatic hypertension), which dampens footplate mobility medially and which is directly related to a relative inner ear or labyrinthine hyperpressure. Since the footplate mobility is only dampened and not fixed, a stapedial reflex may still be elicited.
Adolescent↗
[Anatomical landmarks and surgical limits in the suboccipital transmeatal approach to the acoustic neuroma].
INTRODUCTION: To completely remove the intracanalicular portion of the acoustic neuroma through the retrosigmoid approach, we must open the posterior wall of the internal auditory canal (IAC). Therefore, drilling the IAC is one of the key steps we need to take in the transmeatal surgical approach. Nevertheless, there are no clear anatomical landmarks to identify structures such as the semicircular canals, the jugular bulb or air cells. The individual anatomical variations and those caused by the tumour itself make preoperative evaluation essential if we wish to avoid complications such as deafness, cerebrospinal fluid leakage, bleeding and air embolism. OBJECTIVE: We describe here the personal experience of the senior author (EU) in drilling the posterior wall of the IAC, with special reference to the anatomical landmarks and surgical limits in the suboccipital approach to the intracanalicular portion of the acoustic neuromas. MATERIAL AND METHODS: This work is based on anatomical data obtained from drilling human temporal bones obtained from cadavers, along with our experience with 20 patients who were operated on for acoustic neuroma using Samii's technique. RESULTS: We did not operate on any purely intracanalicular neurinomas using this approach. Two tumors were grade II (up to 20mm in diameter), 12 were grade III and 6 were grade IV. We did not drill far enough in any of these cases to be able to see the fundus of the IAC, which was confirmed by postoperative CT. Despite this, the tumor was considered to be completely removed in 17 cases. There was no mortality and we has no major complications as a result of drilling the IAC such as cerebrospinal fluid leakage or air embolism. we cannot guarantee that hearing loss of postoperative deafness, which were the norm except in one case of grade II, were caused by nervous, ischemic or labyrinthine lesions. CONCLUSION: In our material it was not possible to completely expose the IAC fundus using a retrosigmoid approach without injury to labyrinth. The areas in which the risk of secondary complications is greatest when drilling are the inferior wall and the IAC fundus. The medial extension of the suboccipital craniotomy makes drilling the intrameatal tumor exposure easier. There are no intraoperative landmarks to locate the petrous structures while drilling the IAC except for those provided by the surgeon's own experience.
Culture Techniques↗
Recent advances in andrology research: physiopathology and clinical application to fertility and infertility.
Sperm maturation depends on androgen and is mediated by several unidentified epididymal factors: glycoproteins and metabolites affecting acrosomal stability and fertilizing potential of capacitated sperm. Several genes encoding human epididymis-specific proteins have been described. One of the cloned epididymal cDNA encodes a polypeptide designated as HE4 with an estimated molecular mass of 10,000. Leydig cells are rich in lipid droplets and display epithelioid features. These cells have a cord-like arrangement; the cords are formed by one or two closely apposed cells. In between these cells, labyrinthine or canalicular-like spaces are opened in wide perivascular spaces that improve cell secretion of hormones and facilitate their transport into the blood, as well as the traffic of fluids and metabolites. Coagulation and liquefaction in human semen plays an important role in the capacitation of semen. The liquefaction of semen is retarded by the powerful synthetic inhibitors of 6-amidino-2-naphtyl-p-guanidinobenzoate dimethansulfonate.
Animals↗
Craniocerebral injuries.
The postconcussion syndrome is a definite entity, and the patient's complaints are due to legitimate injury. The following three factors contribute to the symptomatology:1. Headaches, caused by the associated sprain of the cervical spine with resultant radiculitis-giving rise to muscle spasm and suboccipital headaches.2. Vertigo, due to trauma of the vestibular and labyrinthine apparatus.3. A vasomotor imbalance and instability resulting from the reaction to "stress."In treatment of an unconscious patient great care must be taken to prevent anoxia and to balance the fluids and electrolytes. If coma develops following brain injury, hemorrhage into the cerebellar fossa as well as above the tentorium must be considered.
Brain↗
Evidence that L-type calcium channels do not contribute to static vestibular function in the guinea pig vestibular nucleus.
Labyrinthine-intact guinea pigs received unilateral, brainstem cannula injections of (1) 2.5 micrograms of the selective dihydropyridine L-type Ca2+ channel agonist, Bay K 8644 (n = 4 animals); (2) 10 micrograms Bay K 8644 (n = 4); 12.5 micrograms of the selective dihydropyridine L-type Ca2+ channel antagonist, nifedipine (n = 4); or 40 micrograms nifedipine (n = 4). In 11/16 cases, the lesion associated with the cannula tip was located within or near the border of the right vestibular nucleus (VN) complex. All cannula injections were delivered in a 1 microliter volume of artificial cerebrospinal fluid (ACSF) and dimethylsulphoxide (DMSO) (70% DMSO, 30% ACSF for Bay K 8644; 80% DMSO, 20% ACSF for nifedipine), adjusted to a pH of approx. 7.0. The effects of these injections were compared with control injections of ACSF/DMSO in our previous studies. Animals were observed for signs of a labyrinthine syndrome (i.e. spontaneous ocular nystagmus, yaw and roll head tilt) directed to the contralateral or ipsilateral side. In no case did Bay K 8644 or nifedipine cause ocular motor or postural symptoms similar to those produced by a unilateral labyrinthectomy. These results suggest that L-type Ca2+ channels do not contribute significantly to the resting activity of VN neurons and therefore do not contribute to static vestibular function at the level of the VN.
3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
[The method of conservative correction of labyrinthine disorders in operations on the ear].
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Adolescent↗
[Controversial aspects of magnetic resonance imaging in sudden onset cochleovestibular diseases].
Sudden deafness and vertigo are a challenge for the otolaryngologist. With its high fluid content, the membranous labyrinth is best evaluated through Magnetic Resonance Imaging (MRI). Recently gadolinium-enhanced MRI has opened new perspectives in the imaging of the pathological labyrinth, able to directly detect labyrinthine lesions. To date the main role of MRI has been to rule out the presence of retrocochlear involvement in patients with sudden deafness and/or vertigo. However, in the past few years, several authors, reporting on gadolinium-enhanced MRI, have described better labyrinthine imaging, revealing direct labyrinth or nerve bundle involvement in all such patients. On the contrary, other studies have not revealed any enhancement of post-contrast labyrinthine images upon MRI but have shown an increase in signal intensity upon T2-weighted images. In this light, the purpose of the present study has been a) to evaluate the prevalence of labyrinthine abnormalities found upon MRI in consecutive patients with sudden deafness and vertigo and b) to assess the correlation between the severity of clinical and audiological findings and the MRI abnormalities encountered. Twelve consecutive patients with sudden hearing loss and/or vertigo were included in the study (age range 9-59 years; 6 males and 6 females). All subjects underwent complete otoneurological examination. MRI was performed with a 0.5 T superconducting magnet system allowing 2 mm-thick sections through the temporal bone. Within 29 days of onset of the complaints all patients were studied both before and after administration of the contrast medium (gadolinium-DTPA, 0.01 mmol/l, i.v.). Two of the 12 subjects had sudden deafness, 5 sudden deafness and vertigo while 5 had vertigo alone. Gadolinium enhancement and/or a high signal intensity upon T2-weighted images of the pathological labyrinth and nerve bundle was observed in 4 patients. The patients were divided into groups by etiology. MRI abnormalities were only found in the group where the etiology was viral. There was no correlation between the severity of clinical findings and the presence of MRI abnormalities nor between MRI and ABR findings. Analysis of such controversial data is discussed, stressing the importance of gadolinium-enhanced MRI of the labyrinth as a new diagnostic tool in sudden deafness and vertigo.
Acute Disease↗
Effect of phenazine methosulfate on electrophysiological activity of the semicircular canal: antioxidant properties of trimetazidine.
Ischemia strokes appear to be the main source of cochleo-vestibular dysfunctions of peripheral origin. The present study aimed to investigate the action of oxygen free radicals on the bioelectric activity of the labyrinthine epithelium, using the frog semicircular canal as an in vitro preparation. We also examined the possible effect of the antianginal drug, trimetazidine (TMZ), under physiological conditions and during the administration of phenazine methosulfate (PMS). The model allows the ionic composition of endolymphatic and perilymphatic fluids bathing the semicircular canal to be dealt with separately. Spontaneous afferent vestibular nerve activity and the endolymphatic potential were recorded under resting conditions. Three additional parameters were investigated during mechanical displacement of the endolymphatic fluid: the ampullar direct current, the nerve direct current and the frequency of the evoked afferent spikes. Addition of TMZ (10(-6) and 10(-5) M, 50 min) into the perilymphatic compartment did not induce significant modifications of the different bioelectrical signals. Generation of oxygen free radicals, through administration of PMS (10(-5) M, 15 min) into the perilymphatic compartment, caused an impairment of all bioelectrical signals, except the ampullar direct current. The spontaneous activity, nerve direct current and frequency of afferent evoked spikes signals were significantly reduced 75 min after the start of PMS administration (-64, -17 and -32%, respectively). In contrast, there was a marked increase of the endolymphatic potential signal (+51%). Addition of TMZ (10(-6) or 10(-5) M) into the perilymph solution reversed the effect of PMS on all bioelectrical signals. These results indicate that TMZ acts as an antioxidant molecule which is capable of protecting the labyrinthine epithelium from the deleterious effect of oxygen radicals. Our data suggest that the protective effect of TMZ on ischemia-induced cochleo-vestibular dysfunctions may be accounted for by the antioxidant properties of this antianginal drug.
Animals↗
Blood distribution in the facial nerve in temporal bones acquired from cases with subarachnoid hemorrhage.
The objectives of this study, conducted in eight temporal bones from five autopsied cases of subarachnoid hemorrhage, were to delineate the communication between the cerebrospinal fluid space and each space of the epineurium, perineurium, and area surrounding the nerve fibers in the facial nerve and to identify the site of hypertonic diuretic solution infusion most likely to decrease the facial nerve swelling at the initial stage of facial palsy. In all eight specimens, blood cells had directly entered into each space from the labyrinthine segment of the facial nerve. The subarachnoid space extended to the first genu of the nerve. The genu, which is the site of the initial lesion in Bell's palsy, is concluded to be the most effective site of intracanal decompression of the facial nerve with hypertonic diuretic solution.
Adult↗
Spontaneous intracranial hypotension: a rare cause of labyrinthine hydrops.
Spontaneous intracranial hypotension should be considered as a possible cause of cochlear hydrops. We report a case of unilateral hearing loss attributed to spontaneous intracranial hypotension on the basis of characteristic abnormalities seen on magnetic resonance imaging. The diagnostic gold standards for intracranial hypotension are lumbar measurement of cerebrospinal fluid pressure and magnetic resonance imaging. The usual treatment is an autologous blood injection into the peridural spaces. The mechanism of hearing loss is thought to involve secondary perilymph depression due to a patent cochlear aqueduct. This perilymph depression would induce a compensatory expansion of the endolymphatic compartment, with a subsequent decrease in basilar or Reissner's membrane compliance. Endolymphatic hydrops can occur in the course of intracranial hypotension, and not only because of abnormal endolymph production or resorption. Hydrops can thus be classified into 1) syndromes of endolymphatic origin and 2) syndromes of perilymphatic origin, in which loss of perilymph induces compensatory expansion of the endolymphatic space.
Adult↗
Disorders of cochlear blood flow.
The cochlea is principally supplied from the inner ear artery (labyrinthine artery), which is usually a branch of the anterior inferior cerebellar artery. Cochlear blood flow is a function of cochlear perfusion pressure, which is calculated as the difference between mean arterial blood pressure and inner ear fluid pressure. Many otologic disorders such as noise-induced hearing loss, endolymphatic hydrops and presbycusis are suspected of being related to alterations in cochlear blood flow. However, the human cochlea is not easily accessible for investigation because this delicate sensory organ is hidden deep in the temporal bone. In patients with sensorineural hearing loss, magnetic resonance imaging, laser-Doppler flowmetry and ultrasonography have been used to investigate the status of cochlear blood flow. There have been many reports of hearing loss that were considered to be caused by blood flow disturbance in the cochlea. However, direct evidence of blood flow disturbance in the cochlea is still lacking in most of the cases.
Animals↗