The Experts below are selected from a list of 15 Experts worldwide ranked by ideXlab platform
Lorne S Parnes - One of the best experts on this subject based on the ideXlab platform.
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the biology of Intratympanic Drug Administration and pharmacodynamics of round window Drug absorption
Otolaryngologic Clinics of North America, 2004Co-Authors: Avik Banerjee, Lorne S ParnesAbstract:: The application of therapeutic agents to the round window holds great promise in the treatment of inner ear disease. The primary benefit of this route of Administration is the ability to achieve high inner ear concentrations of Drugs without systemic side effects. Recent research has elucidated the anatomy and physiology of the round window and provided important information on the inner ear pharmacokinetics and the pharmacodynamics of Drugs administered Intratympanically. Although amino-glycosides and steroids have been most thoroughly studied, many other classes of pharmaceuticals, including otoprotective agents, other antibiotics,and topical anesthetics, have therapeutic potential in the inner ear and will probably be the subject of future studies. The authors believe that direct delivery approaches other than through the round window, perhaps with slow or sustained release formulations, may hold the key to the future treatment of inner ear disorders.
Avik Banerjee - One of the best experts on this subject based on the ideXlab platform.
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the biology of Intratympanic Drug Administration and pharmacodynamics of round window Drug absorption
Otolaryngologic Clinics of North America, 2004Co-Authors: Avik Banerjee, Lorne S ParnesAbstract:: The application of therapeutic agents to the round window holds great promise in the treatment of inner ear disease. The primary benefit of this route of Administration is the ability to achieve high inner ear concentrations of Drugs without systemic side effects. Recent research has elucidated the anatomy and physiology of the round window and provided important information on the inner ear pharmacokinetics and the pharmacodynamics of Drugs administered Intratympanically. Although amino-glycosides and steroids have been most thoroughly studied, many other classes of pharmaceuticals, including otoprotective agents, other antibiotics,and topical anesthetics, have therapeutic potential in the inner ear and will probably be the subject of future studies. The authors believe that direct delivery approaches other than through the round window, perhaps with slow or sustained release formulations, may hold the key to the future treatment of inner ear disorders.
Tsutomu Nakashima - One of the best experts on this subject based on the ideXlab platform.
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Individual differences in the permeability of the round window: evaluating the movement of Intratympanic gadolinium into the inner ear.
Otology & Neurotology, 2009Co-Authors: Mayumi K. Yoshioka, Shinji Naganawa, Michihiko Sone, Seiichi Nakata, Masaaki Teranishi, Tsutomu NakashimaAbstract:OBJECTIVE: Many recent studies have reported on Intratympanic gentamicin therapy for the treatment of intractable Meniere's disease. Intratympanic Administration of steroids has also been used to treat sudden sensorineural hearing loss. These Intratympanic Drug therapies are based on the assumption that the Drug administered Intratympanically enters the inner ear through the round window membrane. We used magnetic resonance imaging (MRI) to evaluate whether and how Intratympanically administered gadolinium (Gd) enters the inner ear. METHODS: GD hydrate was injected Intratympanically through the tympanic membrane using a 23-G needle into 61 ears of 55 patients with inner ear diseases. The injected Gd was diluted 8-fold in saline for injection into 58 ears and 16-fold for 3 ears. Three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) imaging was performed using a 3-Tesla MRI unit 1 day after the Intratympanic injection. RESULTS: In 53 of 61 ears, the Gd-containing inner ear was detected well as a high signal on 3D-FLAIR imaging. However, Gd was not visible in 2 ears with Meniere's disease and in 1 ear with profound deafness. The concentration of Gd in the perilymph was lower in 4 ears with Meniere's disease and 1 ear with delayed endolymphatic hydrops than after Intratympanic Administration of the 16-fold Gd dilution. CONCLUSION: Round window permeability was absent in 5% of ears, and 13% of ears had poor round window permeability. These results should be considered when planning Intratympanic Drug Administration therapy to treat inner ear diseases.
Mayumi K. Yoshioka - One of the best experts on this subject based on the ideXlab platform.
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Individual differences in the permeability of the round window: evaluating the movement of Intratympanic gadolinium into the inner ear.
Otology & Neurotology, 2009Co-Authors: Mayumi K. Yoshioka, Shinji Naganawa, Michihiko Sone, Seiichi Nakata, Masaaki Teranishi, Tsutomu NakashimaAbstract:OBJECTIVE: Many recent studies have reported on Intratympanic gentamicin therapy for the treatment of intractable Meniere's disease. Intratympanic Administration of steroids has also been used to treat sudden sensorineural hearing loss. These Intratympanic Drug therapies are based on the assumption that the Drug administered Intratympanically enters the inner ear through the round window membrane. We used magnetic resonance imaging (MRI) to evaluate whether and how Intratympanically administered gadolinium (Gd) enters the inner ear. METHODS: GD hydrate was injected Intratympanically through the tympanic membrane using a 23-G needle into 61 ears of 55 patients with inner ear diseases. The injected Gd was diluted 8-fold in saline for injection into 58 ears and 16-fold for 3 ears. Three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) imaging was performed using a 3-Tesla MRI unit 1 day after the Intratympanic injection. RESULTS: In 53 of 61 ears, the Gd-containing inner ear was detected well as a high signal on 3D-FLAIR imaging. However, Gd was not visible in 2 ears with Meniere's disease and in 1 ear with profound deafness. The concentration of Gd in the perilymph was lower in 4 ears with Meniere's disease and 1 ear with delayed endolymphatic hydrops than after Intratympanic Administration of the 16-fold Gd dilution. CONCLUSION: Round window permeability was absent in 5% of ears, and 13% of ears had poor round window permeability. These results should be considered when planning Intratympanic Drug Administration therapy to treat inner ear diseases.
Stephen O'leary - One of the best experts on this subject based on the ideXlab platform.
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Gentamicin Administration on the stapes footplate causes greater hearing loss and vestibulotoxicity than round window Administration in guinea pigs.
Hearing Research, 2013Co-Authors: E. B. King, Alec N. Salt, Hayden Eastwood, Stephen O'learyAbstract:Clinically, gentamicin has been used extensively to treat the debilitating symptoms of Meniere’s disease and is well known for its vestibulotoxic properties. Until recently, it was widely accepted that the round window membrane (RWM) was the primary entry route into the inner ear following Intratympanic Drug Administration. In the current study, gentamicin was delivered to either the RWM or the stapes footplate of guinea pigs (GPs) to assess the associated hearing loss and histopathology associated with each procedure. Vestibulotoxicity of the utricular macula, saccular macula, and crista ampullaris in the posterior semicircular canal were assessed quantitatively with density counts of hair cells, supporting cells, and stereocilia in histological sections. Cochleotoxicity was assessed quantitatively by changes in threshold of auditory brainstem responses (ABR), along with hair cell and spiral ganglion cell counts in the basal and second turns of the cochlea. Animals receiving gentamicin applied to the stapes footplate exhibited markedly higher levels of hearing loss between 8–32kHz, a greater reduction of outer hair cells in the basal turn of the cochlea and fewer normal type I cells in the utricle in the vestibule than those receiving gentamicin on the RWM or saline controls. This suggests that gentamicin more readily enters the ear when applied to the stapes footplate compared with RWM application. These data provide a potential explanation for why gentamicin preferentially ablates vestibular function while preserving hearing following transtympanic Administration in humans.