Omental flap and titanium plates provide structural stability and protection of the mediastinum after extensive sternocostal resection.

Major tenets in the reconstruction of the anterolateral chest wall include preservation of structural stability and function and coverage of the mediastinal contents. To reach these goals, a rigid support has been advocated by several authors. We describe a patient with extensive anterolateral defect after sternocostal resection of chondrosarcoma.

Comparison of salicylate- and quinine-induced tinnitus in rats: development, time course, and evaluation of audiologic correlates.

Background: Salicylate and quinine have been shown to reliably induce short-term tinnitus when administered at high doses. The present study compared salicylate and quinine-induced tinnitus in rats using the gap prepulse inhibition of acoustic startle (GPIAS).

Methods: Twenty-four rats were divided into 2 groups; the first group (n = 12) was injected with salicylate (300 mg kg d), whereas the second (n = 12) was treated with quinine orally at a dose of 200 mg kg d.

Separate and combined effects of Sod1 and Cdh23 mutations on age-related hearing loss and cochlear pathology in C57BL/6J mice.

Both the ahl allele of Cdh23 and the null mutation of Sod1 have been shown to contribute to age-related hearing loss (AHL) in mice, but mixed strain backgrounds have confounded analyses of their individual and combined effects. To test for the effects of Sod1 deficiency independently from those of Cdh23(ahl), we produced mice with four digenic genotypes: Sod1(+/+)Cdh23(ahl)(/ahl), Sod1(+/+)Cdh23(+/+), Sod1(-/-)Cdh23(ahl)(/ahl), and Sod1(-/-)Cdh23(+/+), all on a uniform C57BL(/)6J strain background. We assessed hearing loss by ABR threshold measurements and evaluated cochlear pathologies in age-matched mice of each digenic combination.

Effects of sodium salicylate on spontaneous and evoked spike rate in the dorsal cochlear nucleus.

Spontaneous hyperactivity in the dorsal cochlear nucleus (DCN), particularly in fusiform cells, has been proposed as a neural generator of tinnitus. To determine if sodium salicylate, a reliable tinnitus inducer, could evoke hyperactivity in the DCN, we measured the spontaneous and depolarization-evoked spike rate in fusiform and cartwheel cells during salicylate superfusion. Five minute treatment with 1.

Molecular characterization and phenotypic expression of mutations in genes for gonadotropins and their receptors in humans.

Gonadotropin hormones undergo important dynamic changes during life. Their rise during puberty stimulates gonadal steroid secretion, triggering the development of secondary sexual characteristics and the acquisition of fertility. The full spectrum of possible mutations and polymorphisms in the human gonadotropins and in their receptor genes has been described in recent years.

Salicylate-induced degeneration of cochlea spiral ganglion neurons-apoptosis signaling.

Aspirin, whose active ingredient is sodium salicylate, is the most widely used drug worldwide, but it is not recommended for children because it may cause Reye's syndrome. High doses of salicylate also induce temporary hearing loss and tinnitus; while these disorders are believed to disappear when treatment is discontinued some data suggest that prolonged treatment may be neurotoxic. To investigate its ototoxicity, immature, postnatal day 3 rat cochlear organotypic cultures were treated with salicylate.

Too much of a good thing: long-term treatment with salicylate strengthens outer hair cell function but impairs auditory neural activity.

Aspirin has been extensively used in clinical settings. Its side effects on auditory function, including hearing loss and tinnitus, are considered as temporary. A recent promising finding is that chronic treatment with high-dose salicylate (the active ingredient of aspirin) for several weeks enhances expression of the outer hair cell (OHC) motor protein (prestin), resulting in strengthened OHC electromotility and enhanced distortion product otoacoustic emissions (DPOAE).

Noise trauma impairs neurogenesis in the rat hippocampus.

The hippocampus, a major site of neurogenesis in the adult brain, plays an important role in memory. Based on earlier observations where exposure to high-intensity noise not only caused hearing loss but also impaired memory function, it is conceivably that noise exposure may suppress hippocampal neurogenesis. To evaluate this possibility, nine rats were unilaterally exposed for 2 h to a high-intensity, narrow band of noise centered at 12 kHz at 126 dB SPL.

Functional and structural changes in the chinchilla cochlea and vestibular system following round window application of carboplatin.

OBJECTIVE: In chinchillas, moderate doses of carboplatin administered systemically selectively destroy inner hair cells and type I vestibular hair cells; however, it is unclear whether this unique damage pattern persists if carboplatin is applied directly to the cochlea, how quickly the damage develops and what cell death pathways are involved. STUDY DESIGN: To address these questions, carboplatin (5 mg/ml, 50 µl) was applied to the round window. RESULTS: Carboplatin caused a rapid decline in distortion product otoacoustic emissions, significantly increased compound action potential thresholds and caused massive inner hair cell loss and less severe outer hair cell loss.

[Streptomycin-induced apoptosis of rat cochlear hair cell cultured in vitro].

Objective: To evaluate if caspase pathway was involved in streptomycin-induced cell apoptosis in cochlear hair cells.

Methods: F344 rats at postnatal day 3 or 4 were used for the study in cochlear organotypic cultures. The cochlear basilar membrane was micro-dissected out and cultured overnight, and then treated with 1 mmol/L streptomycin for 24 hours.

Age-related hearing loss in C57BL/6J mice is mediated by Bak-dependent mitochondrial apoptosis.

Age-related hearing loss (AHL), known as presbycusis, is a universal feature of mammalian aging and is the most common sensory disorder in the elderly population. The molecular mechanisms underlying AHL are unknown, and currently there is no treatment for the disorder. Here we report that C57BL/6J mice with a deletion of the mitochondrial pro-apoptotic gene Bak exhibit reduced age-related apoptotic cell death of spiral ganglion neurons and hair cells in the cochlea, and prevention of AHL.

Brain derived neurotrophic factor and neurotrophic factor 3 modulate neurotransmitter receptor expressions on developing spiral ganglion neurons.

Cochlear spiral ganglion neurons (SGN) provide the only pathway for transmitting sound evoked activity from the hair cells to the central auditory system. Neurotrophic factor 3 (NT-3) and brain derived neurotrophic factor (BDNF) released from hair cells and supporting cells exert a profound effect on SGN survival and neural firing patterns; however, it is unclear what the effects NT-3 and BDNF have on the type of neurotransmitter receptors expressed on SGN. To address this question, the whole-cell patch clamp recording technique was used to determine what effect NT-3 and BDNF had on the function and expression of glutamate, GABA and glycine receptors (GlyR) on SGN of cochlea from postnatal C57 mouse.

Behaviorally measured audiograms and gap detection thresholds in CBA/CaJ mice.

Tone detection and temporal gap detection thresholds were determined in CBA/CaJ mice using a Go/No-go procedure and the psychophysical method of constant stimuli. In the first experiment, audiograms were constructed for five CBA/CaJ mice. Thresholds were obtained for eight pure tones ranging in frequency from 1 to 42 kHz.

Inflammatory role of ASC in antigen-induced arthritis is independent of caspase-1, NALP-3, and IPAF.

Because IL-1beta plays an important role in inflammation in human and murine arthritis, we investigated the contribution of the inflammasome components ASC, NALP-3, IPAF, and caspase-1 to inflammatory arthritis. We first studied the phenotype of ASC-deficient and wild-type mice during Ag-induced arthritis (AIA). ASC(-/-) mice showed reduced severity of AIA, decreased levels of synovial IL-1beta, and diminished serum amyloid A levels.

Mechanisms of rapid sensory hair-cell death following co-administration of gentamicin and ethacrynic acid.

Concurrent administration of a high dose of gentamicin (GM; 125mg/kg IM) and ethacrynic acid (EA; 40mg/kg IV) results in rapid destruction of virtually all cochlear hair cells; however, the cell death signaling pathways underlying this rapid form of hair-cell degeneration are unclear. To elucidate the mechanisms underlying GM/EA-mediated cell death, several key cell death markers were assessed in the chinchilla cochlea during the early stages of degeneration. In the middle and basal turns of the cochlea, massive hair-cell loss including destruction of the stereocilia and cuticular plate occurred 12h after GM/EA treatment.

Emerging pharmacotherapy of tinnitus.

Tinnitus, the perception of sound in the absence of an auditory stimulus, is perceived by about 1 in 10 adults, and for at least 1 in 100, tinnitus severely affects their quality of life. Because tinnitus is frequently associated with irritability, agitation, stress, insomnia, anxiety and depression, the social and economic burdens of tinnitus can be enormous. No curative treatments are available.

[Correlation between reduction of distortion product otoacoustic emission and percentage of outer hair cell missing in chinchillas].

Objective: To explore the quantitative relationship between the reduction of distortion product otoacoustic emission (DPOAE) and the percentage of outer hair cell loss.

Methods: Coadministration of cisplatin (0.2 mg/kg) and ethacrynic acid (40 mg/kg) were used to establish a cochlear lesion model in chinchillas.

[Ototoxic effects of streptomycin in vestibular organotypic cultures].

Objective: To investigate the ototoxic effects of streptomycin in vestibular organotypic cultures.

Methods: F344 rats with age at postnatal day three or four were used for this study. The maculae of saccule and utricle were routinely dissected out and cultured with serum-free medium containing various dose of streptomycin for 24 hours.

Central auditory plasticity after carboplatin-induced unilateral inner ear damage in the chinchilla: up-regulation of GAP-43 in the ventral cochlear nucleus.

Inner ear damage may lead to structural changes in the central auditory system. In rat and chinchilla, cochlear ablation and noise trauma result in fiber growth and synaptogenesis in the ventral cochlear nucleus (VCN). In this study, we documented the relationship between carboplatin-induced hair cell degeneration and VCN plasticity in the chinchilla.

Analysis of cochlear protein profiles of Wistar, Sprague-Dawley, and Fischer 344 rats with normal hearing function.

Differences in the expression of cochlear proteins are likely to affect the susceptibility of different animal models to specific types of auditory pathology. However, little is currently known about proteins that are abundantly expressed in inner ear. Identification of these proteins may facilitate the search for biomarkers of susceptibility and intervention targets.

Differential expression of apoptosis-related genes in the cochlea of noise-exposed rats.

Exposure to intense noise induces apoptosis in hair cells in the cochlea. To identify the molecular changes associated with noise-induced apoptosis, we used quantitative real-time PCR to evaluate the changes in 84 apoptosis-related genes in cochlear samples from the sensory epithelium and lateral wall. Sprague-Dawley rats exposed to a continuous noise at 115 dB SPL for 2 h.

Auditory proteomics: methods, accomplishments and challenges.

The advent of contemporary proteomic technologies has ushered in definite advances to the field of auditory research and has provided the potential for a dramatic increase in applications in the near future. Two dimensional-differential gel electrophoresis (2D-DIGE) followed by matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS), antibody microarrays and tandem mass spectrometry have evolved as the major tools. Each of these techniques has unique features with distinct advantages.

The fetal hypothalamus has the potential to generate cells with a gonadotropin releasing hormone (GnRH) phenotype.

Background: Neurospheres (NS) are colonies of neural stem and precursor cells capable of differentiating into the central nervous system (CNS) cell lineages upon appropriate culture conditions: neurons, and glial cells. NS were originally derived from the embryonic and adult mouse striatum subventricular zone. More recently, experimental evidence substantiated the isolation of NS from almost any region of the CNS, including the hypothalamus.