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680 results on '"Hansen, Marlan R."'

152. A Series of Case Studies of Tinnitus Suppression With Mixed Background Stimuli in a Cochlear Implant

Author

Tyler, Richard S., primary, Keiner, A. J., additional, Walker, Kurt, additional, Deshpande, Aniruddha K., additional, Witt, Shelley, additional, Killian, Matthijs, additional, Ji, Helena, additional, Patrick, Jim, additional, Dillier, Norbert, additional, van Dijk, Pim, additional, Lai, Wai Kong, additional, Hansen, Marlan R., additional, and Gantz, Bruce, additional

Published
2015
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157. Acoustic plus electric speech processing: Long-term results.

Author

Gantz, Bruce J., Dunn, Camille C., Oleson, Jacob, and Hansen, Marlan R.

Abstract

Objective: Few studies have investigated the stability of residual hearing and speech perception outcomes in individuals who were implanted with a shorter electrode device.Study Design: Longitudinal, single-subject design.Methods: Fifty subjects who received a Nucleus Hybrid (Cochlear, Sydney, Australia) short electrode cochlear implant (CI) and had a minimum of 2 years (and up to 15 years) of postoperative longitudinal experience were included in this study. Twenty-three subjects received a Nucleus Hybrid S8 (S8); 14 subjects received a Nucleus Hybrid L24 (L24); and 13 received a Nucleus Hybrid S12 (S12). Audiometric thresholds and consonant-nucleus-consonant (CNC) words were collected pre- and postoperatively for up to 15 years for the S8 subjects and for up to 7 years for the S12 and L24 subjects. AzBio Sentences in multi-talker babble was collected for up to 7 years on the S12 and L24 subjects.Results: Longitudinally, 83% of the S8 subjects, 92% of the S12 subjects, and 86% of the L24 subjects maintained a functional hearing pure-tone average (PTA) (125-500 Hz). Predicted change using a piecewise linear mixed model in PTA over time showed a postoperative linear decrease in hearing for each group until 0.5 years, after which the PTA stabilizes and is maintained. The averaged individual data for CNC and AzBio sentences show a significant improvement in scores by 0.25 to 0.5 years postimplantation, after which scores start to reach their maximum.Conclusion: This long-term study demonstrates that acoustic-electric processing hearing and improvement in speech understanding in quiet and in noise can be accomplished and sustained for many years with a short electrode CI.Level Of Evidence: 2C. Laryngoscope, 128:473-481, 2018. [ABSTRACT FROM AUTHOR]

Published
2018
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158. A simple assessment tool for evaluation of cadaveric temporal bone dissection.

Author

Mowry, Sarah E., Woodson, Erika, Gubbels, Samuel, Carfrae, Matt, and Hansen, Marlan R.

Abstract

Educational Objective: Objective metrics in skilled-based educational courses allow trainees and instructors to assess performance and monitor progress. The objective is to validate a concise, easy-to-use instrument for assessment of resident skill during a timed cadaveric temporal-bone (CTB) dissection.Study Design: Retrospective analysis.Methods: An instrument was developed to assess resident performance on a yearly timed microdissection of CTB. Five neurotologists participated in the assessment. Each reviewer's score was compared to the score given by the senior neurotologist each year for every resident. Spearman's correlation analysis was then used to assess the reproducibility of the instrument in assessing resident performance. The ability of the instrument to distinguish among experienced and novice trainees and to demonstrate improvement with experience were also assessed.Results: The instrument was created and used for 6 years. Thirty residents were assessed. Correlation of scores between the senior neurotologist and the other neurotologist together was very high (r = 0.883, P < 0.001). Three specific tasks distinguished novice from senior dissectors: posterior canal, opening the membranous labyrinth, and disruption of the ossicular chain.Conclusion: A new instrument for assessment of resident skill on CTB dissection is presented. The instrument is easy to use, and scores derived from it are consistent across reviewers. The new instrument distinguishes experienced trainees from novice trainees, is sensitive to individual experience, and has proved useful in providing trainees with objective performance measures.Level Of Evidence: NA. Laryngoscope, 128:451-455, 2018. [ABSTRACT FROM AUTHOR]

Published
2018
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160. Epidermal growth factor receptor as a novel molecular target for aggressive papillary tumors in the middle ear and temporal bone

Author

Kawabata, Shigeru, primary, Hollander, M. Christine, additional, Munasinghe, Jeeva P., additional, Brinster, Lauren R., additional, Mercado-Matos, José R., additional, Li, Jie, additional, Regales, Lucia, additional, Pao, William, additional, Jänne, Pasi A., additional, Wong, Kwok-Kin, additional, Butman, John A., additional, Lonser, Russell R., additional, Hansen, Marlan R., additional, Gurgel, Richard K., additional, Vortmeyer, Alexander O., additional, and Dennis, Phillip A., additional

Published
2015
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171. Antifouling Photograftable Zwitterionic Coatings on PDMS Substrates

Author

Leigh, Braden L., Cheng, Elise, Xu, Linjing, Derk, Alexis, Hansen, Marlan R., and Guymon, C. Allan

Abstract

The foreign body response (FBR) to implantable materials can negatively impact performance of medical devices such as the cochlear implant. Engineering surfaces that resist the FBR could lead to enhanced functionality including potentially improving outcomes for cochlear implant recipients through reduction in fibrosis. In this work, we coat poly(dimethylsiloxane) (PDMS) surfaces with two zwitterionic polymers, poly(sulfobetaine methacrylate) (pSBMA) and poly(carboxybetaine methacrylate) (pCBMA), using a simultaneous photografting/photo-cross-linking process to produce a robust grafted zwitterionic hydrogel. reduce nonspecific protein adsorption, the first step of the FBR. The coating process uses benzophenone, a photografting agent and type II photoinitiator, to covalently link the cross-linked zwitterionic thin film to the PDMS surface. As the concentration of benzophenone on the surface increases, the adhesive strength of the zwitterionic thin films to PDMS surfaces increases as determined by shear adhesion. Additionally, with increased concentration of the adsorbed benzophenone, failure of the system changes from adhesive delamination to cohesive failure within the hydrogel, demonstrating that durable adhesive bonds are formed from the photografting process. Interestingly, antifouling properties of the zwitterionic polymers are preserved with significantly lower levels of nonspecific protein adsorption on zwitterion hydrogel-coated samples compared to uncoated controls. Fibroblast adhesion is also dramatically reduced on coated substrates. These results show that cross-linked pSBMA and pCBMA hydrogels can be readily photografted to PDMS substrates and show promise in potentially changing the fibrotic response to implanted biomaterials.

Published
2019
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172. ERbB2 Trafficking and Signaling in Human Vestibular Schwannomas

Author

IOWA UNIV IOWA CITY, Hansen, Marlan R, IOWA UNIV IOWA CITY, and Hansen, Marlan R

Abstract

We find that the ErbB2 receptor tyrosine kinase is active in vestibular schwannoma (VS) cells and drives proliferation. Our overall hypothesis is that defects in merlin lead to constitutive ErbB2 activation at the cell membrane and that inhibition of ErbB2 will reduce the survival of VS cells and potentiate the effects of radiation on VSs. In this report we show that VS cells, which lack functional merlin, constitutively express activated ErbB2 in lipid rafts contributing to their proliferative potential; this is related to the merlin status of the cells. Furthermore, protein kinase A inactivates merlin by phosphorylation in Schwann cells in vitro and in vivo following denervation, correlated with movement of ErbB2 into lipids rafts and re-entry into the cell cycle. VS cells are relatively radioresistance, due at least in part, to persistent JNK activity which promotes cell survival and limits oxidative stress. Finally, inhibition of ErbB2 reduces VS cell radiosensitivity whereas activation of ErbB2 enhances radiosensitivity, likely by regulating cell proliferation., The original document contains color images.

Published
2011

173. ErbB2 Trafficking and Signaling in Human Vestibular Schwannomas

Author

IOWA UNIV IOWA CITY, Hansen, Marlan R, IOWA UNIV IOWA CITY, and Hansen, Marlan R

Abstract

We find that the ErbB2 receptor tyrosine kinase is active in vestibular schwannoma (VS) cells and drives proliferation. Our overall hypothesis is that defects in merlin lead to constitutive ErbB2 activation at the cell membrane and that inhibition of ErbB2 will reduce the survival of VS cells and potentiate the effects of radiation on VSs. In this report we show that VS cells, which lack functional merlin, constitutively express activated ErbB2 in lipid rafts contributing to their proliferative potential; this is related to the merlin status of the cells. Furthermore, protein kinase A inactivates merlin by phosphorylation in Schwann cells in vitro and in vivo following denervation, correlated with movement of ErbB2 into lipids rafts and re-entry into the cell cycle. VS cells are relatively radioresistance, due at least in part, to persistent JNK activity which promotes cell survival and limits oxidative stress. Finally, inhibition of ErbB2 reduces VS cell radiosensitivity whereas activation of ErbB2 enhances radiosensitivity, likely by regulating cell proliferation., The original document contains color images.

Published
2010

174. ErbB2 Trafficking and Signaling in Human Vestibular Schwannomas

Author

IOWA UNIV IOWA CITY, Hansen, Marlan R, Clark, J J, Yue, Wie Y, Goswami, Prabhat C, Gantz, Bruce J, IOWA UNIV IOWA CITY, Hansen, Marlan R, Clark, J J, Yue, Wie Y, Goswami, Prabhat C, and Gantz, Bruce J

Abstract

We find that the ErbB2 receptor tyrosine kinase is active in vestibular schwannoma (VS) cells and drives proliferation. Our overall hypothesis is that defects in merlin lead to constitutive ErbB2 activation at the cell membrane and that inhibition of ErbB2 will reduce the survival of VS cells and potentiate the effects of radiation on VSs. In this report we show that VS cells, which lack functional merlin, constitutively express activated ErbB2 in lipid rafts contributing to their proliferative potential. Furthermore, protein kinase A inactivates merlin by phosphorylation in Schwann cells in vitro and in vivo following denervation, correlated with movement of ErbB2 into lipids rafts and re-entry into the cell cycle. VS cells are relatively radioresistance, due at least in part, to persistent JNK activity which promotes cell survival and limits oxidative stress. Finally, inhibition of ErbB2 reduces VS cell radiosensitivity whereas activation of ErbB2 enhances radiosensitivity, likely by regulating cell proliferation. Neurofibromatosis type II (NF2) results from mutation in the tumor suppressor gene, merlin, leading to the development of multiple intracranial and spinal tumors including schwannomas. Schwann cells (SCs) of the vestibular nerve are most commonly affected and bilateral vestibular schwannomas (VSs) is a hallmark of NF2. We have begun exploring factors that contribute to VS growth. We find that the ErbB2 receptor tyrosine kinases is active in VS cells and drives proliferation. Our overall hypothesis is that defects in merlin lead to constitutive ErbB2 activation at the cell membrane and that inhibition of ErbB2 will reduce the survival of VS cells and potentiate the effects of radiation on VSs. Our object is to test this hypothesis using cultured primary human VS cells., The original document contains color images.

Published
2009

176. ErbB2 Trafficking and Signaling in Human Vestibular Schwannomas

Author

IOWA UNIV IOWA CITY, Hansen, Marlan R., Clark, J. J., Yue, Wie Y., Goswami, Prabhat C., Gantz, Bruce J., IOWA UNIV IOWA CITY, Hansen, Marlan R., Clark, J. J., Yue, Wie Y., Goswami, Prabhat C., and Gantz, Bruce J.

Abstract

We find that the ErbB2 receptor tyrosine kinase is active in vestibular schwannoma (VS) cells and drives proliferation. Our overall hypothesis is that defects in merlin lead to constitutive ErbB2 activation at the cell membrane and that inhibition of ErbB2 will reduce the survival of VS cells and potentiate the effects of radiation on VSs. In this report we show that VS cells, which lack functional merlin, constitutively express activated ErbB2 in lipid rafts contributing to their proliferative potential. Furthermore, protein kinase A inactivates merlin by phosphorylation in Schwann cells in vitro and in vivo following denervation, correlated with movement of ErbB2 into lipids rafts and re-entry into the cell cycle. VS cells are relatively radioresistance, due at least in part, to persistent JNK activity which promotes cell survival and limits oxidative stress. Finally, inhibition of ErbB2 reduces VS cell radiosensitivity whereas activation of ErbB2 enhances radiosensitivity, likely by regulating cell proliferation., The original document contains color images.

Published
2008

187. Canal wall reconstruction and conductive hearing preservation for temporal bone paraganglioma.

Author

Hoyne, Danielle S., Mowry, Sarah E., and Hansen, Marlan R.

Abstract

The article describes the modified infratemporal fossa (ITF) approach for canal wall reconstruction (CWR) for middle ear paraganglioma. Topics discussed include the ways in which the modified approach helps limit conductive hearing loss (CHL) and improve patients' quality of life, the tumor margins and neurovascular structures for which the technique provides access and the common limitations of traditional surgery for paragangliomas.

Published
2016
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196. Do steroids improve recovery in vestibular neuritis?

Author

Solis, Roberto N., Sun, Daniel Q., Tatro, Eric, and Hansen, Marlan R.

Abstract

The article offers information on the Vestibular neuritis, one of the three most common causes of peripheral vestibulopathy. It mentions the first clinical trial in a double-blind, placebo-controlled, crossover study that demonstrated benefit of short-term corticosteroid therapy in treating patients with acute VN; and also mentions analysis of variance showed methylprednisolone alone being significantly effective in improving peripheral vestibular function.

Published
2019
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197. Functional Variants inNOS1andNOS2AAre Not Associated with Progressive Hearing Loss in Ménière's Disease in a European Caucasian Population

Author

Gazquez, Irene, primary, Lopez-Escamez, Jose A., additional, Moreno, Antonia, additional, Campbell, Colleen A., additional, Meyer, Nicole C., additional, Carey, John P., additional, Minor, Lloyd B., additional, Gantz, Bruce J., additional, Hansen, Marlan R., additional, Santina, Charles C. Della, additional, Aran, Ismael, additional, Soto-Varela, Andres, additional, Santos, Sofia, additional, Batuecas, Angel, additional, Perez-Garrigues, Herminio, additional, Lopez-Nevot, Alicia, additional, Smith, Richard J.H., additional, and Lopez-Nevot, Miguel A., additional

Published
2011
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