Search results for "cochlea"

Use of electron spectroscopic imaging to determine element composition of the melanin granules in the stria vascularis of the guinea pig.

1998

Electron spectroscopic imaging (ESI) was used to analyze the element content of melanin granules in the stria vascularis seen in ultrathin sections of Spurr-embedded cochleae of the guinea pig. To determine element composition, ESI images were taken at different ionization edges, and non-specific background signals were subtracted digitally by an image processing system. The presence of calcium and nitrogen in the melanin granules could be demonstrated clearly. The calcium identified in the melanin granules was then compared with the spatial distributions of calcium binding sites after the application of an antimonate precipitation method, which was used to localize loosely bound calcium. D…

Introduction to the superior olivary complex

2000

The brainstem efferent acoustic chiasm in pigmented and albino rats

2015

Abstract The present study examined whether structural peculiarities in the brain-efferent pathway to the organ of Corti may underlie functional differences in hearing between pigmented and albino individuals of the same mammalian species. Pigmented Brown-Norway rats and albino Wistar rats received unilateral injections of an aqueous solution of the retrograde neuronal tracer Fluorogold (FG) into the scala tympani of the cochlea to identify olivocochlear neurons (OCN) in the brainstem superior olivary complex. After five days, brains were perfusion-fixed and brainstem sections were cut and analyzed with respect to retrogradely labeled neurons. Intrinsic neurons of the lateral system were lo…

Auditory, speech and language development in young children with cochlear implants compared with children with normal hearing.

2010

Abstract Objective This study had two aims: (1) to document the auditory and lexical development of children who are deaf and received the first cochlear implant (CI) by the age of 16 months and the second CI by the age of 31 months and (2) to compare these children's results with those of children with normal hearing (NH). Methods This longitudinal study included five children with NH and five with sensorineural deafness. All children of the second group were observed for 36 months after the first fitting of the device (cochlear implant). The auditory development of the CI group was documented every 3 months up to the age of two years in hearing age and chronological age and for the NH gro…

Cortical neuroplasticity in children after early cochlear implantation

2009

Hearing is crucial to learn and use language. Loss of hearing in children affects the development of speech, language and cognitive abilities, and severely impairs social capabilities. Thus, efforts to restore auditory perception are determinative and research should be focused on factors likely to bring about the best prognosis. Numerous experimental observations demonstrate that there is a sensitive or critical period for cochlear implantation. Implantations performed in prelingually deaf children in this period are associated with better results in terms of speech recognition and language acquisition. This is the time period in which brain plasticity shows its highest level of developmen…

Breeding success of a colony of Boat-billed Herons Cochlearius cochlearius (Ciconiiformes: Ardeidae) in pasturelands of Costa Rica

2014

The breeding success of a double-brooding colony of Boat-billed Herons Cochlearius cochlearius was studied in pasturelands of Costa Rica. Mean clutch size in the first clutches (2.9 eggs/nest) was higher than in second and repeat clutches (2.3 eggs/nest). Breeding success was similar in the first attempt and second attempts(20.7 % and 21.7 %, respectively). In both attempts earlier nests enjoyed a higher breeding success. Starvation of the youngest chicks within the nest and destruction of nests by bad weather conditions were the main factors related to nestling death. No effects of human activity on the reproduction of the breeding colony were observed. Rev. Biol. Trop. 54 (4): 1131-1134. …

Nitric oxide--a versatile key player in cochlear function and hearing disorders.

2012

Nitric oxide (NO) is a signaling molecule which can generally be formed by three nitric oxide synthases (NOS). Two of them, the endothelial nitric oxide synthase (eNOS) and the neural nitric oxide synthase (nNOS), are calcium/calmodulin-dependent and constitutively expressed in many cell types. Both isoforms are found in the vertebrate cochlea. The inducible nitric oxide synthase (iNOS) is independent of calcium and normally not detectable in the un-stimulated cochlea. In the inner ear, as in other tissues, NO was identified as a multitask molecule involved in various processes such as neurotransmission and neuromodulation. In addition, increasing evidence demonstrates that the NO-dependent…

Electron microscopic localization of nitric oxide I synthase in the organ of Corti of the guinea pig

1997

Nitric oxide synthase (NOS) activity has been detected previously in the mammalian cochlea at a light microscopic level. Here we present results of electron microscopic analysis for post-embedding immunoreactivity of neural-type NOS I in the cochlea of the guinea pig. Strong enzyme immunoreactivity was identified in the cytoplasm of inner and outer hair cells. Gold-labeled NOS I antibodies were mainly located in electron-dense areas of the cytoplasm, whereas electron-lucent regions of the receptor cells were nearly free from any immunoreactivity. In both types of hair cells anti-NOS I antibodies were also visible in the cuticular plates, hair bundles and nuclei. Further ultrastructural anal…

Association between obstructive apnea syndrome during sleep and damages to anterior labyrinth: Our experience

2019

The obstructive sleep apnea syndrome is a chronic condition characterized by frequent episodes of collapse of the upper airways during sleep. It can be considered a multisystem disease. Among the districts involved, even the auditory system was seen to be concerned. It was enrolled a population of 20 patients after polysomnographic diagnosis of OSAS (Apnea Hypopnea Index > 10) and a control group of 28 healthy persons (Apnea Hypopnea Index < 5). Each patient has been subjected to Pure Tone Audiometry, Tympanometry, study of Acoustic Reflex, Otoacoustic Emissions and Auditory Brainstem Response. Moreover they were submitted to endoscopy of upper airway with Muller Maneuver and Epworth …

Novel form of X-linked nonsyndromic hearing loss with cochlear malformation caused by a mutation in the type IV collagen gene COL4A6

2013

Hereditary hearing loss is the most common human sensorineural disorder. Genetic causes are highly heterogeneous, with mutations detected in >40 genes associated with nonsyndromic hearing loss, to date. Whereas autosomal recessive and autosomal dominant inheritance is prevalent, X-linked forms of nonsyndromic hearing impairment are extremely rare. Here, we present a Hungarian three-generation family with X-linked nonsyndromic congenital hearing loss and the underlying genetic defect. Next-generation sequencing and subsequent segregation analysis detected a missense mutation (c.1771G>A, p.Gly591Ser) in the type IV collagen gene COL4A6 in all affected family members. Bioinformatic analysis an…