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At least 415 records · Page 23Linked to original sources
PubMed1989

[Glycerol opening of blood-labyrinth barrier using electron-opaque tracer ferritin].

Fifteen guinea pigs were divided into three groups: the control, the ferritin and the glycerol-ferritin groups. In the first group, no any medication had been given; in the second group, ferritin 1 gm/kg was injected via the jugular vein; in the third group, 50% glycerol 3 ml/kg was injected 30, 60 and 120 minutes prior to the injection of ferritin. Striae were removed, fixed and embedded in Epon. Ultra-thin sections were cut and observed under electron microscope. No ferritin molecule was seen in the control group. In the ferritin group, the ferritin particles were seen in stria capillary only. In the glycerol-ferritin group, the ferritin molecules had entered the endothelial cells of stria capillary at 30 minutes. Ferritin molecules had got into stria vascularis and accumulated around the mitochondria at 60 minutes. The electron-opaque tracers had migrated to the apex of the marginal cells along microtubular system and permeated to the endolymphatic space through cell membranes and junctions. The ferritin particles appeared at the surface of marginal cells in the endolymphatic space at 120 minutes. The results indicate that glycerol can serve as an opener of blood-labyrinth barrier.

Animals↗
PubMed1985

[Modulating action of barium and other ions on the sensory activity of frog labyrinth].

The effect of Ba2+, TEA, 4-AP and CoCl2 on the EPSP and spike discharges recorded from single fibres of the posterior nerve in the isolated frog labyrinth has been investigated. In Ca-free solution Ba2+ preserved, at low concentration (0.3 mM), the resting activity and at higher levels (up to 6 mM) it resulted in a pronounced facilitation of the EPSP and spike discharges. Facilitation increased on increasing Ba2+ concentration up to 4-5 mM and it was more evident in those units exhibiting a low resting spike firing. The effect of Ba2+ (1 mM) was completely antagonized by 10 mM Ca2+ X CoCl2 (3 mM) suppressed the resting rate at the normal external Ca2+ concentration; the Co2+ block was partially relieved by 1.8 mM Ba2+ X TEA (20 mM) evoked a clear-cut increase in the EPSP and spike discharges which, however, was less consistent than that produced by Ba2+. By comparing the effect of TEA on the spike frequency with that obtained at different Ba2+ levels, the Ba2+ capacity to carry the Ca2+ current was dissected. Such an effect is dose-dependent and it is more evident in low-frequency units. Conversely, 4-AP did not affect the resting discharge frequency. These results indicate that either the Ca2+ or the Ba2+ current sustain the transmitter release at the cyto-neural junction. The effect of TEA suggests that the Ca2+-dependent K+ current may play an important role in supporting the neurosecretory process by controlling the membrane potential of the hair cells.

4-Aminopyridine↗
PubMed1986

The endocytosis of asbestos by mouse peritoneal macrophages and its long-term effect on iron accumulation and labyrinth formation.

The effect of a single intraperitoneal injection of crocidolite asbestos fibres on the peritoneal cell population were studied. Attention was paid to the changes in the proportions taken by the various types of cell in this population after peritoneal stimulation as well as the handling of asbestos fibres by the peritoneal cells and the formation of asbestos bodies. Intraperitoneal administration of crocidolite led to an influx of inflammatory cells into the peritoneal cavity. The asbestos fibres were phagocytosed and gradually cleared from the peritoneal cavity. Long before this clearance was completed, the peritoneal cell population had returned to the steady state. The stimulated peritoneal macrophages showed increasing concentrations of iron in both lysosomes and the cytoplasm. At later time points, residual bodies containing iron and asbestos fibres were seen frequently in macrophages, but asbestos bodies were not found. As a reaction to the administration of crocidolite asbestos, macrophages from the peritoneal cavity develop tubular systems (labyrinths) that increase in number and size.

Animals↗
PubMed1977

[Specificity of the effect of thrombin on the chemoreceptors of the frog carotid labyrinth].

Perfusion of thrombin and trypsin solutions through the frog carotid labyrinth acts on the carotid chemoreceptors and evokes reflex response of the anticoagulating system. The similarity of effects of both these agents seems to be due to similarity of their structures. Other agents acting on the frog vascular chemoreceptors: sodium chloride hypoxia, lobeline,--cause no activation of the reflex anticoagulating system. Thrombin is concluded to be the adequate and specific irritant of the vascular chemoreceptors of the frog anticoagulating system.

Animals↗
PubMed1979

The labyrinth of the American bullfrog.

The labyrinth of the American bullfrog (Rana catesbiana) has been studied by aid of light and electron microscopy. Cell counts and sensory area mapping has been made and it has been shown that scanning electron microscopy is the most appropriate technique at present for cell counts.

Animals↗
PubMed1987

[The organogenesis of the membranous labyrinth in Polypterus senegalus Cuvier, 1829 (Pisces, Holostei, Polypteridae)].

The organogenesis of the membranous labyrinth of Polypterus senegalus is described. 1. The otocyst seems to be formed by the invagination of a thick portion of the deeper layer of the epidermis. 2. The 3 semi-circular canals are formed by 3 pairs of invaginations of the wall of the otocyst and at the expense of its volume; the anterior vertical canal is completed first, followed by the horizontal and then the posterior vertical one; the ampullae, not very developed, appear a long time after the formation of their corresponding canals: that of the horizontal canal appears first, followed by that of the posterior and finally that of the anterior one. 3. The sensory areas derive from a common macula which subsequently divides into 2 zones, the anterior one giving rise to the utricular macula and the anterior and horizontal cristae, the posterior one giving rise to the posterior crista and the saccular macula; from the latter subsequently develops the lagenar macula. 4. The otoconiae appear as soon as the otocyst forms; the otoliths are agglomerations of otoconias brought together by an interstitial cement. 5. The endolymphatic primordium is formed before that of the semi-circular canals; the endolymphatic sack becomes voluminous and spreads over the brain as far as the sagittal plane.

Animals↗
PubMed1986

[Symmetry of the horizontal semicircular canal of the labyrinth].

Out of 30 adult human craniums and with a portable tomograph (vestibulograph) allowing 5 degrees of liberty (2 rotations and 3 translocations), a "medio-labyrinthic" plane was determined from the two "vestibions" put in the main X rays axis. Under those requirements, the lateral ductus becomes constantly visible on the cranian teleradiographies and the founded horizontal directions are identical either for the left than for the right (Student t's test always shows non significant differences).

Adult↗
PubMed1986

Ventricular labyrinths of the ependyma adjacent to the hypothalamic paraventricular nucleus in the turtle Mauremys caspica.

Labyrinthic recesses projecting to the subependymal tissue have been observed in the ependyma of the III ventricle in close relation to the neurons of the hypothalamic paraventricular nucleus in the turtle Mauremys caspica. There seems to be evidence of a direct contact between the paraventricular nucleus neurons and the cerebrospinal fluid whose physiological significance is discussed in the present work.

Animals↗
PubMed1986

Suboccipital removal of vestibular neurinoma with preservation of the labyrinth.

Hearing preservation in surgery for vestibular neurinoma depends on several factors, the first of which is, of course, early diagnosis. If a small enough tumor is found in a patient with reasonable hearing, there is a fair chance that it can be removed in toto with preservation of some hearing. We report data from 40 operated patients; the question was whether the identification of the transverse crest and the removal of tumor from the lateral part of the internal auditory meatus could be achieved without opening of perilymph spaces. In most of these ears the angle from the medial edge of a suboccipital craniectomy allowed the surgeon a direct view of the lateral part of the internal auditory meatus with good exposure of the transverse crest without his having to open the labyrinth. So far we believe that loss of hearing caused during these operations is mainly due to the unfavorable location of the cochlear blood supply through the meatus.

Ear, Inner↗
PubMedDate not supplied

[Use of the labyrinth test in gerontologic functional diagnosis].

The authors inform on the basic application possibilities of the labyrinth-test in gerontological functional diagnoses. They are able to refer to experiences gained from their investigations with 365 subjects from 18 to 75 years of age (197 female, 168 male ones). They recommend this psychological procedure as a practicable and economical method to assess age-dynamics of over-lapping sub-aspects of intelligence (orientational capacity, transitional ability, problem-solutional attitude, memory performance).

Adolescent↗
PubMed1983

The ethmoid labyrinth. An anatomical and radiological study.

After an osteological description of the ethmoid labyrinth, the authors examine the radiological techniques which best display the topography, interrelation and configuration of the ethmoid cells. On the basis of their observations they conclude that standard radiographic examinations cannot provide an adequately clear anatomical-radiological representation of these cells and must therefore be supplemented with polytomography and computerized tomography.

Ethmoid Sinus↗
PubMed1983

The ethmoid labyrinth: an anatomical and comparative radiological study.

After an osteologic description of the ethmoid labyrinth, the radiologic techniques which best display the ethmoidal cell topography, relationships and configuration are examined. On the basis of these observations it is concluded that standard radiographic tests cannot give a clear anatomic-radiologic representation of the ethmoid cells and that they must be supplemented with tomography.

Adult↗
PubMed1983

[The size of the ethmoidal labyrinth in children of various ages].

The length, height and width of the ethmoidal labyrinth have been measured in children from birth up to 16 years of age (125 osseous total preparations). Coefficients of the regressive equations have been estimated (the sixth degree polynomial) in order to calculate the prognosticated dimentions. The data obtained can be used in surgery.

Adolescent↗
PubMed1981

[Treatment of acute left cardiac insufficiency: a labyrinth without the thread of Ariane?].

The final picture of left ventricular failure depends at least as much upon its four mechanisms of compensation (increase in preload, in afterload, in heart rate and, as an attempt, in myocardial contractility) as upon its primary factor (decrease in contractility). The complexity of all possible combinations between those various factors has good chances to bring about confusion in therapeutics if one doesn't dispose of a method, a kind of Ariane's thread, making it possible (1) to define some wide orientations to start with, and thereafter (2) to state precisely the way out of that labyrinth. This method must be founded on an accurate physiological basis and therefore requires cardiac catheterization. In all cases the purpose is to get an adequate cardiac output with comfort to the patient and at a low cost to his myocardium. Further adjustment of that treatment essentially founded on hemodynamics, must however take into account its uncertain physiological results in various organs, estimated from clinical and biological information.

Aldosterone↗
PubMed1981

[Tonic mechanisms of efferent inhibition in the frog labyrinth].

Activation of the efferent system of the isolated group labyrinth inhibits the afferent EPSP and spike discharge by releasing ACh, which opens the Cl- channel of the hair cells membrane. Experiments in which increasing amounts of Cl- in the bath are replaced by equivalent amounts of Br-, NO2-, NO3-, CH3 CO2-, SO4(2-), CH3CH2CO2-, CH3(CH2)2CO2-, CH3(CH2)3CO2- benzoate, indicate that all these anions are able to penetrate the postsynaptic membrane, since full inhibition was invariably elicited. On the other hand, when citrate or isethionate are substituted for Cl- inhibition disappeared. In the presence of anions which are known to chelate calcium, its bath concentration was adequately increased. The presence of inhibition of Ringer-benzoate (benzoate ion size 6.5 A) and its disappearance in Ringer-citrate (8 A) or in Ringer-isethionate (greater than 10 A), suggests that the Cl- channel is at least 7 A in diameter, a size significantly larger than at other inhibitory synapses. Since metabolic inhibitors (DNP 0.1 mM and NaN3 1 mM) or acetazolamide (5 mM) and ammonium acetate (10 mM), which are known to block active Cl- pumping in other systems, do not affect the efferent synapse it appears difficult to interfere with the mechanisms which maintain the Cl- concentration gradient across the hair cell membrane.

Animals↗
PubMed1980

[Axonal organization of the peripheral efferent system in the frog labyrinth].

The purpose of the present work is to investigate the distribution of the nerve fibres subserving efferent control in frog labyrinth. Following electrical stimulation of a twig of the isolated VIII nerve compound action potentials could be picked up from the others nervous twigs. Denervation experiments suggest that these compound potentials are sustained by efferent fibres which branch in the VIII nerve providing collaterals to otolith and canal organs. This axonal organization, therefore, enables single efferent neurones to control the activity arising from different types of labyrinthine receptors.

Action Potentials↗
PubMed1994

Immunocytochemistry of carbonic anhydrase and non-radioactive detection of its RNA by in situ hydridization in the chick embryo membranous labyrinth.

An immunocytochemical study was carried out with the aim to localize carbonic anhydrase isozymes (CA I and CA II) in the chick membranous labyrinth. CA I and CA II were localized in the same cells and, during the early developmental stages, were diffusely present in the labyrinthine epithelium. At later stages, the sensorial epithelium of the maculae acusticae, crista ampullaris and papilla basilaris, as well as labyrinthine dark cells and the epithelium of the endolymphatic sac strongly stained by the immunocytochemical procedure. In 1-day and 1-week old chicks, CA was present in the same sites as at advanced embryonal stages. In order to detect mRNA for carbonic anhydrase II, in situ hybridization was also used. Strong hybridization signals were observed in the sensorial epithelium of the saccule, utricle and crista ampullaris, in the tegmentum vasculosum, the endolymphatic sac, the erythrocytes and the choroid plexus in embryos older than 10 days. This positivity persisted until the day after hatching. The authors discuss the significance of labyrinthine CA and, based on in situ hybridization results, suggest that melanocytes do not provide labyrinthine dark cells with enzyme protein.

Animals↗
PubMed1995

[Analysis of antigenity of membranous labyrinth proteins of guinea pigs].

An electrophoretic dot immunobinding assay and a modified western blotting method were established. The components and antigenity of the membranous labyrinth proteins of guinea pigs were analysed. There are the same epitopes between some components of the antigen, between the antigen and extractives of acoustic nerve, cochlear nuclei, kidney and Klebsiella pneumoniae. The antigen distributes in stria vascularis, spiral ligament, spiral ganglion, the organ of Corti and Reissner's membrane etc.

Animals↗