Search results for "Inner ear"
showing 10 items of 58 documents
17β-Estradiol Reduces Nitric Oxide Production in the Guinea Pig Cochlea
2013
Intense noise exposure and the application of ototoxic substances result in increased levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS), such as nitric oxide (NO). In order to reduce the free NO concentration in the inner ear under pathological conditions, the use of natural cytoprotective substances such as 17β-estradiol is a promising therapeutic concept. In male guinea pigs the organ of Corti and the lateral wall were isolated from the cochlea and afterwards incubated for 6 h in cell-culture medium. 17β-Estradiol was adjusted in 2 concentrations to organ cultures of the right ears (12 animals per concentration). The left ears were used as controls. The NO produc…
COX-2 expression in the guinea pig cochlea is partly altered by moderate sound exposure.
2006
The cyclooxygenase-2 isoform (COX-2) was found recently to be constitutively expressed in the guinea pig inner ear. To gain knowledge about its role in sound perception, alterations in the COX-2 level of moderate noise-stimulated cochleae were determined. Staining intensities were quantified in different regions using an immunohistochemical staining procedure and computer-assisted system. After 70 dB and 90 dB noise exposure for 1 h at 8000 Hz, COX-2 downregulation was observed in the organ of Corti, which was most prominent in Deiters' cells near Hensen cells and outer hair cells. In pillar cells, COX-2 levels were only slightly reduced after 70 dB but strongly diminished after 90 dB expos…
Immunoelectron-microscopic localization of synaptophysin in the organ of Corti of the guinea pig.
1997
Synaptophysin has been localized previously in the mammalian cochlea at the light-microscopic level and in few reports by electron microscopy using either a preincubation procedure or the avidin-biotin reaction. Here we present results of the electron-microscopic analysis for postembedding immunoreactivity of synaptophysin in the cochlea of the guinea pig of LR-White-embedded samples. Strong synaptophysin immunoreactivity is located in the cytoplasm of the efferent nerve endings at the base of inner and outer hair cells. Besides this, some antibodies to synaptophysin were also identified in the cytoplasm of outer hair cells. To get more information about the cellular content of synaptophysi…
Possible roles of nitric oxide in the physiology and pathophysiology of the guinea pig cochlea.
2000
Two nitric oxide synthase isoforms (NOS-I and NOS-III) are present in the mammalian cochlea, and many regulatory functions of the inner ear could be mediated by NO. In this study, cochlear potentials and immunohistochemical measures were analyzed by changing the concentration of NO in the guinea pig during intracochlear and intravenous application of an NOS inhibitor and an NO donor. In anesthetized guinea pigs the NOS inhibitor NG-nitro-L-arginine-methylester (L-NAME) was applied by intracochlear perfusion or intravenously. The cochlear potentials and blood pressure were measured during and after the application. Cochleae were removed and prepared for morphological and immunohistochemical …
Immunoelectron microscopic localization of nitric oxide synthase III in the guinea pig organ of Corti
1998
Nitric oxide synthase III (NOS III) was identified in the guinea pig cochlea on an ultrastructural level using a post-embedding immunolabeling procedure. Ultrathin sections of London Resin (LR) White-embedded specimens were incubated with various concentrations of a commercially available antibody to NOS III and the immunoreactivity visualized by a gold-labeled secondary antibody. Analysis of ultrathin sections of the organ of Corti in the second turn of the cochlea showed that NOS III could be localized in the endothelial cells of the blood vessels under the basilar membrane, which was comparable to its location in similar cells types in various biological systems. Besides this, NOS III wa…
Lärm als Umweltproblem
1976
Noise as an Environmental Problem. Anatomical structure and physiological function of the human ear are described. It is shown that constant noise stress leads to damage of certain parts of the inner ear. These damages proceed characteristically and may be diagnosed relatively early by means of audiometric tests. VDI-instructions 2058 (sheet 2) prescribes screening-tests for an earliest possible detection of incipient noise damage. In addition to ear-damaging effects of noise there have also been recorded physiological reactions under noise influence. Such disturbances, however, cannot as yet be described as an “Extraaural disease”. On the other hand, the fact that high sound intensities of…
Differences in inner ear asymmetry levels between slow-moving and fast-moving primates
2021
International audience; The vestibular system of the inner ear, highly involved in maintaining balance during activities and positional behaviour of animals, has been deeply studied in order to link its morphology with the specific type of locomotion. Previous studies (e.g. Perier et al. 2016, Gonzales et al. 2018) have shown that, in primates, the amount of morphological variation is higher in slow-moving species than in fast-moving ones. These results indicate a lower selective pressure and a reduced functional demand for postural adjustments in the former group, and a higher selective pressure for balance and postural capabilities in the latter. In this study, we assessed if the differen…
Dexamethasone treatment of naïve organ of Corti explants alters the expression pattern of apoptosis-related genes.
2009
Dexamethasone treatment of organ of Corti explants challenged with an ototoxic level of an inflammatory cytokine modulates NFkappaB signaling and the expression levels of both pro-and anti-apoptosis-related genes. It is not known if naïve organ of Corti explants will respond in a similar manner to treatment with a corticosteroid. This study examines the response of naïve organ of Corti explants to treatment with dexamethasone.Three-day-old rat organ of Corti explants were cultured for 1, 2, or 4 days. Four-day in vitro cultures were fixed, stained with FITC-phalloidin and hair cells were counted. ELISA was performed on 2-day cultures to determine the levels of phosphorylated nuclear factor …
Scaffold protein harmonin (USH1C) provides molecular links between Usher syndrome type 1 and type 2.
2005
Contains fulltext : 48386.pdf (Publisher’s version ) (Closed access) Usher syndrome (USH) is the most frequent cause of combined deaf-blindness in man. USH is clinically and genetically heterogeneous with at least 11 chromosomal loci assigned to the three USH types (USH1A-G, USH2A-C, USH3A). Although the different USH types exhibit almost the same phenotype in human, the identified USH genes encode for proteins which belong to very different protein classes and families. We and others recently reported that the scaffold protein harmonin (USH1C-gene product) integrates all identified USH1 molecules in a USH1-protein network. Here, we investigated the relationship between the USH2 molecules a…
Patologie rare dell'orecchio
2012
After fifty years of experience, mostly spent in ENT surgery at the University of Palermo, I have pleasure in presenting this Atlas of rare diseases of the ear, including clinical cases observed and documented during this long period from 1958 to 2006. We would prefer to divide all the case studies into three chapters: the outer ear, middle ear and inner ear.