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At least 19 recordsLinked to original sources
PubMed1976

[Development of the internal ear in albino rat embryos subjected to transverse acceleration at + 3 G. Note 3: First observations on the ultrastructural picture of the labyrinth. 1st ultrastructural studies of the labyrinth].

Marked body size reduction (minus 50.5%), and delayed head and body skeletal development were noted in albino rat embryos following exposure of the mother to +/- 3 G acceleration for 3 hr/day between the 10th and 19th day of pregnancy. In addition, electron microscope examination of the inner ear showed signs of greater functional activity of the labyrinth, unaccompanied by reduction of development. Semicircular canal cells and size, in fact, were normal in the crests and at a distance from the latter. There was a marked increase in the number of mitochondria in the cells, in ER area and volume, and A and B glycogen granule richness compared with the controls, these being all signs of considerable activity. The findings substantiate prior histological and histochemical observations: the physiological stimulus offered by acceleration is highly specific for the inner ear structure, particularly that of the labyrinth, to the point where the handicap imposed by the circulatory hypoxia caused by such acceleration, by disturbing the mother-foetus circulation, is overcome.

Acceleration↗
PubMed1992

The significance for postoperative hearing of preserving the labyrinth in acoustic neurinoma surgery.

Among 186 patients with preoperative hearing, a total of 189 acoustic neurinomas were removed through a lateral suboccipital approach with anatomical preservation of the cochlear nerve. Functional hearing was preserved in 92 (49%) of these patients; despite anatomical preservation of the cochlear nerve, deafness was the result in 51% of the series. Many factors have been considered to cause hearing loss in patients whose cochlear nerve was intact after surgery; these include nerve retraction, nerve or cochlear ischemia, overheating and vibration damage to the nerve, and opening of the labyrinth. To evaluate the significance of injury to the labyrinth in postoperative hearing loss, a prospective study was undertaken. High-resolution computerized tomography studies through the inner ear with bone algorithm were performed pre- and postoperatively. The postoperative status of the labyrinth was classified into three patterns: intact, fenestrated, and widely opened. Injury to the labyrinth occurred in 30% of the cases. The most frequently injured labyrinth structures were the crus commune of the posterior and superior semicircular canals (52%), the posterior semicircular canal (23%), the vestibule (21%), and the superior semicircular canal (4%). A statistically significant relationship was found between injury to the labyrinth and deafness, elevated thresholds, and lower discrimination values at pure-tone audiograms and speech audiometry (p < 0.0001). The degree of the injury (comparison between fenestration and wide opening of the labyrinth) was also significantly related to postoperative deafness (p < 0.0001). Disturbance of the inner-ear fluids was considered to be the cause of the hearing loss. In 12 patients labyrinth injury was not associated with deafness. This finding may support the existence of mechanisms of cochlear protection. The homeostatic function of the endolymphatic sac was considered to play an important role in recovery of damaged hearing in these 12 cases.

Adolescent↗
PubMed1977

On the vascular architecture of the carotid labyrinth in Cynops pyrrhogaster and Onychoactylus japonicus.

The fine vascular arrangement of the carotid labyrinth in two species of urodeles, Cynops pyrrhogaster and Onychodactylus japonicus was investigated. India ink-gelatin injected preparations were examined under the dissecting microscope. Resin casts of the blood vessels prepared using the method of MURAKAMI (1971) were observed in the scanning electron microscope. In both species, the common carotid artery terminated in the central chamber from which arose two retia mirabilia, i.e. an external carotid rete and an internal carotid rete. The external carotid artery arose recurrently from the external carotid rete, whereas the internal carotid artery received vessels from the internal carotid rete which apparently occupied more than two thirds of the carotid labyrinth. The present observations indicate that the previous descriptions of the urodele carotid labyrinth should be corrected: a vascular ring exists around the common carotid artery and the latter shows a corresponding narrowing at the entrance to the carotid labyrinth; the vascular ring forms the most proximal part of the external carotid rete; the central chamber occupies only a part of the proximal end of the carotid labyrinth; the internal carotid rete and the external carotid rete constitute a continuous rete mirabile; and a distinct furrow exists in the boundary between these two portions of the rete mirabile. Individual variations were frequently encountered, but were confined to the external carotid artery and its tributaries. The complicated and elaborate vascular architecture of the amphibian carotid labyrinth suggests that this organ should exert blood-flow regulating the probably other unknown functions as an effector organ in addition to its accepted activity as a chemo- and baro-receptor.

Ambystoma↗
PubMedDate not supplied

Radiologic diagnosis of labyrinthitis ossificans.

Labyrinthitis ossificans is the pathological ossification of the membranous labyrinthine spaces in response to processes which are destructive of the membranous labyrinth or the endosteum of the otic capsule. It has been primarily a histopathologic diagnosis. Complex motion tomography however, allows a detailed view of the osseous labyrinth and permits the diagnosis in the living state. Radiologic documentation of labyrinthitis ossificans is objective evidence of a process destructive of the membranous labyrinth. It supports the likelihood of an absence of cochlear and vestibular function. It alerts the surgeon to the possible obliteration of key inner ear anatomical landmarks.

Aged↗
PubMed1976

Asymmetric tonic labyrinth reflexes and their interaction with neck reflexes in the decerebrate cat.

1. Tonic labyrinth and neck reflexes were studied separately and in combination in the decerebrate cat with C1 and C2 spinal roots cut. Reflex effects were observed as changes in length of the isotonically loaded medial head of triceps. 2. The tonic labyrinth reflexes acted asymmetrically on the medial head of triceps. Side-down rotation of the head produced shortening in medial triceps, whereas side-up rotations of the head resulted in a lengthening. 3. The tonic neck reflexes acted asymmetrically on the medial head of triceps. Side-down rotations of the neck produced a lengthening of medial triceps, whereas side-up rotations of the neck resulted in shortening. 4. Labyrinth and neck reflexes produce opposite effects on the same limb extensor muscle so that, if the neck innervation is intact, head tilting produces no change in muscle length. 5. It is suggested that the interaction between the labyrinth and neck reflexes contributes to the stability of the trunk, allowing the head to move freely on the body without affecting this stability. Labyrinth and neck reflexes need therefore to be considered together as a single system.

Animals↗
PubMed1977

Quantitive studies of the reactions to horizontal angular accelerations in axolotls. II. head-turning reflexes in animals with a supernumerary pair of labyrinths.

In axolotls (Ambystoma mexicanun) the labyrinths and the associated parts of the medulla were doubled artificially. In these so-called tandem-heads the vestibular afferent fibres from both labyrinths on one side united within the medulla to form common bundles. The head-turning reflexes following impulse acceleration and during long-lasting acceleration were measured quantitatively and compared with those for normal animals. The form and the time-course of the reactions were almost identical in both groups. Tandem-heads showed a linear relationship between stimulus intensity and reaction strength, parallel to that in normal animals but with a greater reaction for a given stimulus. Consequent to this shift in the relationship, there was a significant decrease in the reaction threshold. The removal of one horizontal semicircular canal in tandem-heads proved that both pairs of labyrinths were functionally connected with the brain. It was suggested that during ontogenesis there exists a kind of specificity in the connexion of vestibular fibres. From the parallel shift of the intensity functions it was concluded that the input from both pairs of labyrinths in tandem-heads is not simply accumulate but compared with a reference parameter, which is also double in tandem-heads.

Ambystoma↗
PubMed1975

Spontaneous cerebrospinal fluid otorrhea. Congenital anomaly of bony labyrinth a possible cause.

A patient had recurrent meningitis as a result of a congenital anomaly of the bony labyrinth. As far as could be traced in the literature, this was the first time that an isolated congenital anomaly of the bony labyrinth could be shown to be the origin of spontaneous cerebrospinal fluid otorrhea and the resulting recurrent meningitis. In cerebrospinal fluid otorrhea of unknown origin, tomographic x-ray examination of the bony labyrinth is of utmost importance. For the detection of the finer details is the bony structure of the labyrinth, this tomography should be done according to one of the multidirectional techniques.

Adolescent↗
PubMed1976

EEG-studies on the phases of sleep and wakefulness after bilateral labyrinth destruction.

The dynamics of the state of wakefulness, slow and paradoxical sleep after labyrinth destruction was studied in chronic cats. The states were assessed according to the behaviour, EEG, myogram and eye movements. The labyrinth destruction was combined (chemical and mechanical). Bilateral labyrinth deafferentation results in a decrease in the duration of wakefulness from 30 to 17 per cent, p less than 0.001. At the same time paradoxical sleep increased from 4 to 8 per cent, p less than 0.001. This increase is due to both the greater average number of paradoxical sleep episodes and a higher average duration of the individual episode. The latency of the first appearance of a paradoxical sleep episode is considerably shortened after labyrinth destruction.

Animals↗
PubMed1975

Ultrastructural observations on the maturation of the placental labyrinth of the golden hamster (days 10 to 16 of gestation).

Morphogenesis of the labyrinthine part of the chorioallantoic placenta of the golden hamster between day 10 of gestation and term (day 16) was studied by light and electron microscopy. During this period the labyrinth increases greatly in both size and complexity. Trabeculae of the labyrinth, thin partitions composed of trophoblastic tissue and fetal capillaries which delimit the maternal blood spaces, apparently proliferate both by appositional and interstitial growth. From the time of its formation (day 9 of gestation) until term the labyrinth is hemotrichorial in organization (i.e. three layers of trophoblast separate maternal blood from fetal capillaries). Both the inner and intermediate layers of trophoblast (layers III and II, respectively) are syncytial. The outer trophoblastic layer (III), which is in direct contact with maternal blood, remains cellular, although many of its component cells grow to giant cell dimensions ("labyrinthine giant cells"). Between the tenth and fourteenth days of gestation the anatomical barrier to diffusion between maternal and fetal blood is progressively reduced. This is accomplished both by gradual attenuation of the trophoblastic layers and fetal capillary endothelium and by the formation of discontinuities (gaps) in layer I, and diaphragmed fenestrae in fetal capillary endothelium. The labyrinthine placental barrier is fully developed and probably attains maximal functional efficiency by the fourteenth day of gestation. Late in the fifteenth day of gestation, a few hours before parturition, distinct degenerative changes are apparent in the trophoblastic layers and fetal capillaries of the trabeculae. The factors responsible for initiation these degenerative changes and the onset of parturition are still controversial.

Animals↗
PubMed1979

The passage of lymphatic leukemia L1210 cells injected into glass bead labyrinth: their flow and retention.

Leukemia L1210 cells and normal lymphocytes were injected into the glass bead packing perfused with a medium containing serum proteins in concentration sufficient to greatly reduce the surface adhesion. The passage of radioactively labeled cells introduced as a concentrated suspension, was studied by the analysis of transit-dilution curves. It was demonstrated that a fraction of cells was retained in the labyrinth; other parameters characterizing the cell flow were similar to those of the medium. The mechanism of the arrest of cells is discussed: it is related to geometrical features of the labyrinth and the hydrodynamic forces influencing the cell surface interactions. Intense washing of the glass bead column results in the release of only a minor fraction of cells which were previously arrested. When the L1210 cells which have passed through the labyrinth without being trapped are reinjected into another glass bead layer, their retention is similar to that observed after the first injection; it appears, therefore, that the L1210 cells are uniform as concerns the properties which are important for surface interactions under flow conditions.

Animals↗
PubMedDate not supplied

Labyrinthitis ossificans.

Three cases with postinflammatory inner ear sequelae are presented to illustrate unusual histopathologic changes. Endolymphatic hydrops without changes in the perilymphatic system was present in one ear following "influenza" meningitis and labyrinthitis ossificans in the contralateral ear. The characteristic histopathological changes of the temporal bones with hematogenic bacterial infection were an extensive labyrinthine ossification associated with a generalized sclerotic change of the whole periotic bone. Bony fixation of the stapedial footplate occurred with the generalized inflammatory process of the otic capsule. Severe and diffuse labyrinthitis ossificans occurred in one case due to tympanogenic inflammation spreading through the round window membrane in the course of suppurative otitis media. A general immunosuppression leading to fatal termination was the apparent factor predisposing to the inner ear complication.

Adult↗
PubMed1976

Experimental viral infections of the inner ear. I. Acute infections of the newborn hamster labyrinth.

Acute viral infections of the inner ear were produced in neonatal hamsters. Viruses were inoculated percutaneously through the temporal cartilage into the endolymphatic and perilymphatic spaces of the labyrinth or were inoculated intracerebrally to reach the perilymphatic spaces via the cochlear aqueduct. Selective vulnerability of inner ear structures was demonstrated using a variety of viruses. Influenza virus infected only the mesenchymal cells of the perilymphatic channels of the cochlea; mumps virus infected principally endolymphatic structures; herpes simplex virus infected primarily the sensory cells of the labyrinth; and rubeola and vaccinia viruses infected both perilymphatic and endolymphatic cells.

Acute Disease↗
PubMedDate not supplied

Viral labyrinthitis -- an experimental study.

Summary--An attempt was made to produce viral labyrinthitis in the rhesus monkey. Rhesus monkeys are susceptible to the mumps virus. Nine animals were used. After removal of the stapes, the left oval windows were plugged with Gelfoam soaked in a culture of live mumps virus; right oval windows were plugged with Gelfoam soaked in killed cultures. Animals were sacrificed at different time intervals, postinfection. In eight of the nine animals there was seroconversion from negative to positive; however, none of the animals developed the histologic changes of viral labyrinthitis.

Animals↗
PubMed1978

[Experience with using amedin in children with movement disorders of extrapyramidal and labyrinth origin].

Using previously obtained data concerning the effectivity of amedin in motor and speech disorders due to muscular dystonia the drug was used for the treatment of 50 children from 3.5 months to 18 years, with motor disorders of an extrapyramidal and labyrinth nature. A high therapeutical effectivity of amedin in an increased pathological activity of tonic cervical and labyrinth reflexes in infants and in torsion spasm of school age children is demonstrated.

Adolescent↗
PubMed1992

Extraembryonic tissue changes induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin and 2,3,4,7,8-pentachlorodibenzofuran with a note on direction of maternal blood flow in the labyrinth of C57BL/6N mice.

Histologic changes in extraembryonic and embryonic tissues induced by 3 or 6 micrograms 2,3,7,8-tetrachlorodibenzo-p-dioxin/kg (TCDD) or 80 micrograms 2,3,4,7,8-pentachlorodibenzofuran/kg/day (4-PeCDF) were studied 24 h after the last of four daily doses administered orally to C57BL/6N mice on days 10-13 of pregnancy. Both test compounds ruptured (1) the embryo-maternal vascular barrier in the labyrinth, which resulted in hemorrhage of embryonic blood into the maternal circulation, (2) the visceral yolk sac membrane with the embryonic blood from the vitelline vessels escaping into the uterine, exocelomic and amniotic cavities, and (3) the maternal vascular spaces of the placental periphery resulting in hemorrhages into the interconceptal space. The role of the hemorrhagic lesions in the induction of cleft palate and hydronephrosis by the two compounds remains to be investigated. The presence of embryonic nucleated erythroblasts that hemorrhaged into the maternal lacunar network allowed the identification of maternal venous channels in the placenta. It revealed that (1) the labyrinth could be tentatively divided into two caudocranially oriented zones, an arterial and a venous zone; (2) the maternal blood in the labyrinthine lacunae circulated from the arterial to the venous zone, somewhat parallel to the uterine axis; and (3) the largest maternal vessels in the center of the placenta hitherto named the "central maternal artery," was in fact, venous.

Animals↗
PubMed1975

Neural pathways from the vestibular labyrinths to the flocculus in the cat.

In decerebrate, unanesthetized cats, responses in the flocculus were evoked by electric stimulation of the vestibular nerves and by natural stimulation of horizontal head angular acceleration. Field potentials in the flocculus and intracellular recording from Purkinje cells following vestibular nerve stimulation indicated that the responses were produced by mossy fiber inputs. Field potentials evoked from the contralateral labyrinth were as large as those from the ipsilateral one. There was considerable convergence of bilateral labyrinthine mossy fiber inputs to a Purkinje cell. In view of the effects of incision at the midline of the cerebellum and the brain stem, inputs from the contralateral labyrinth were mainly conveyed through the midline of the brain stem and partly through the midline of the cerebellum. Primary vestibular afferents were involved in the transcerebellar crossed pathway. Fibers of the secondary vestibular neurons projecting to the contralateral flocculus were implicated in the brain stem-mediated pathway and, in part, presumably in the transcerebellar crossed pathway. About one-third of the axon spikes examined in the flocculus responded to horizontal head angular acceleration. Commissural inhibition was observed in more than half of the axon spikes in the flocculus which were presumed to be mono- or polysynaptically activated from the vestibular nerve.

Animals↗
PubMed1992

Ontogeny of substance P-, CGRP-, and VIP-containing nerve fibers in the amphibian carotid labyrinth of the bullfrog, Rana catesbeiana. An immunohistochemical study.

The ontogeny of substance P, CGRP (calcitonin gene-related peptide), and VIP (vasoactive intestinal polypeptide) containing nerve fibers in the carotid labyrinth of the bullfrog, Rana catesbeiana, was examined by the peroxidase-antiperoxidase method. The time of appearance of these three peptides was different for each. First, CGRP fibers appeared in the wall of the carotid arch and external carotid arteries, and in a thin septum between these two arteries at an early stage of larval development (stage III). At stage V, substance P immunoreactive fibers appeared, and VIP fibers were detected at the early metamorphic stage (stage XXII). Up to the completion of metamorphosis, the number of these fibers remained low. From 1 to 5 weeks after metamorphosis, substance P, CGRP, and VIP fibers increased in number to varying degrees. By 8 weeks after metamorphosis, the distribution and abundance of these fibers closely resembled those of the adults. Some CGRP and VIP immunoreactive glomus cells were found at the stages immediately before and after the completion of metamorphosis. These findings suggest that substance P, CGRP, and VIP fibers during larval development and metamorphosis may be nonfunctional, and start to participate in vascular regulation only after metamorphosis. The transient CGRP and VIP in some glomus cells may be important for the development of the labyrinth, or may take part in vascular regulation through the close apposition of the glomus and smooth muscle cells (g-s connection).

Animals↗