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

1. Epigenetic reprogramming shapes the cellular landscape of schwannoma

Author

Liu, S. John, Casey-Clyde, Tim, Cho, Nam Woo, Swinderman, Jason, Pekmezci, Melike, Dougherty, Mark C., Foster, Kyla, Chen, William C., Villanueva-Meyer, Javier E., Swaney, Danielle L., Vasudevan, Harish N., Choudhury, Abrar, Pak, Joanna, Breshears, Jonathan D., Lang, Ursula E., Eaton, Charlotte D., Hiam-Galvez, Kamir J., Stevenson, Erica, Chen, Kuei-Ho, Lien, Brian V., Wu, David, Braunstein, Steve E., Sneed, Penny K., Magill, Stephen T., Lim, Daniel, McDermott, Michael W., Berger, Mitchel S., Perry, Arie, Krogan, Nevan J., Hansen, Marlan R., Spitzer, Matthew H., Gilbert, Luke, Theodosopoulos, Philip V., and Raleigh, David R.

Published
2024
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2. Spiral Ganglion Neuron Regeneration in the Cochlea: Regeneration of Synapses, Axons, and Cells

Author

Green, Steven H., Bafti, Sepand, Gansemer, Benjamin M., Shearer, A. Eliot, Rahman, Muhammad Taifur, Warchol, Mark E., Hansen, Marlan R., Coffin, Allison B., Series Editor, Sisneros, Joseph, Series Editor, Avraham, Karen, Editorial Board Member, Popper, Arthur N., Founding Editor, Bass, Andrew, Editorial Board Member, Fay, Richard R., Founding Editor, Cunningham, Lisa, Editorial Board Member, Fritzsch, Bernd, Editorial Board Member, Groves, Andrew, Editorial Board Member, Hertzano, Ronna, Editorial Board Member, Le Prell, Colleen, Editorial Board Member, Litovsky, Ruth, Editorial Board Member, Manis, Paul, Editorial Board Member, Manley, Geoffrey, Editorial Board Member, Moore, Brian, Editorial Board Member, Simmons, Andrea, Editorial Board Member, Yost, William, Editorial Board Member, Warchol, Mark E., editor, and Stone, Jennifer S., editor

Published
2023
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16. Inositol trisphosphate and ryanodine receptor signaling distinctly regulate neurite pathfinding in response to engineered micropatterned surfaces.

Author

Vecchi, Joseph T., Rhomberg, Madeline, Allan Guymon, C., and Hansen, Marlan R.

Subjects
NEUROPROSTHESES, SPIRAL ganglion, RYANODINE receptors, COCHLEAR implants, INOSITOL
Abstract

Micro and nanoscale patterning of surface features and biochemical cues have emerged as tools to precisely direct neurite growth into close proximity with next generation neural prosthesis electrodes. Biophysical cues can exert greater influence on neurite pathfinding compared to the more well studied biochemical cues; yet the signaling events underlying the ability of growth cones to respond to these microfeatures remain obscure. Intracellular Ca2+ signaling plays a critical role in how a growth cone senses and grows in response to various cues (biophysical features, repulsive peptides, chemo-attractive gradients). Here, we investigate the role of inositol triphosphate (IP3) and ryanodine-sensitive receptor (RyR) signaling as sensory neurons (spiral ganglion neurons, SGNs, and dorsal root ganglion neurons, DRGNs) pathfind in response to micropatterned substrates of varied geometries. We find that IP3 and RyR signaling act in the growth cone as they navigate biophysical cues and enable proper guidance to biophysical, chemo-permissive, and chemo-repulsive micropatterns. In response to complex micropatterned geometries, RyR signaling appears to halt growth in response to both topographical features and chemo-repulsive cues. IP3 signaling appears to play a more complex role, as growth cones appear to sense the microfeatures in the presence of xestospongin C but are unable to coordinate turning in response to them. Overall, key Ca2+ signaling elements, IP3 and RyR, are found to be essential for SGNs to pathfind in response to engineered biophysical and biochemical cues. These findings inform efforts to precisely guide neurite regeneration for improved neural prosthesis function, including cochlear implants. [ABSTRACT FROM AUTHOR]

Published
2024
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17. Decreasing the physical gap in the neural-electrode interface and related concepts to improve cochlear implant performance.

Author

Vecchi, Joseph T., Claussen, Alexander D., and Hansen, Marlan R.

Subjects
SPIRAL ganglion, SENSORINEURAL hearing loss, NEUROPROSTHESES, AUDITORY perception, REGENERATIVE medicine, COCHLEAR implants
Abstract

Cochlear implants (CI) represent incredible devices that restore hearing perception for those with moderate to profound sensorineural hearing loss. However, the ability of a CI to restore complex auditory function is limited by the number of perceptually independent spectral channels provided. A major contributor to this limitation is the physical gap between the CI electrodes and the target spiral ganglion neurons (SGNs). In order for CI electrodes to stimulate SGNs more precisely, and thus better approximate natural hearing, new methodologies need to be developed to decrease this gap, (i.e., transitioning CIs from a far-field to near-field device). In this review, strategies aimed at improving the neural-electrode interface are discussed in terms of the magnitude of impact they could have and the work needed to implement them. Ongoing research suggests current clinical efforts to limit the CI-related immune response holds great potential for improving device performance. This could eradicate the dense, fibrous capsule surrounding the electrode and enhance preservation of natural cochlear architecture, including SGNs. In the long term, however, optimized future devices will likely need to induce and guide the outgrowth of the peripheral process of SGNs to be in closer proximity to the CI electrode in order to better approximate natural hearing. This research is in its infancy; it remains to be seen which strategies (surface patterning, small molecule release, hydrogel coating, etc.) will be enable this approach. Additionally, these efforts aimed at optimizing CI function will likely translate to other neural prostheses, which face similar issues. [ABSTRACT FROM AUTHOR]

Published
2024
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22. Rationale for the Development of a Novel Clinical Grading Scale for Postoperative Facial Nerve Function: Results of a Multidisciplinary International Working Group

Author

Carlson, Matthew L., primary, Lohse, Christine M., additional, Agazzi, Siviero, additional, Babu, Seilesh C., additional, Barker, Frederick G., additional, Barnett, Samuel, additional, Bi, Wenya Linda, additional, Biggs, Nigel, additional, Boahene, Kofi D., additional, Breen, Joseph T., additional, Brown, Kevin D., additional, Cayé-Thomasen, Per, additional, Cosetti, Maura K., additional, Deep, Nicholas L., additional, Dey, Jacob K., additional, Dornhoffer, James R., additional, Forner, David, additional, Gurgel, Richard K., additional, Hansen, Marlan R., additional, Hunter, Jacob B., additional, Kalamarides, Michel, additional, Kim, Irene A., additional, King, Andrew T., additional, Kircher, Matthew L., additional, Lassaletta, Luis, additional, Link, Michael J., additional, Lloyd, Simon K.W., additional, Lund-Johansen, Morten, additional, Marinelli, John P., additional, Matthies, Cordula, additional, Mehta, Vikas, additional, Moore, Eric J., additional, Nassiri, Ashley M., additional, Neff, Brian A., additional, Nelson, Rick F., additional, Olson, Jeffrey J., additional, Patel, Neil S., additional, Celda, Maria Peris, additional, Plitt, Aaron R., additional, Price, Daniel L., additional, Thomas Roland, J., additional, Sweeney, Alex D., additional, Tasche, Kendall K., additional, Tatagiba, Marcos, additional, Tveiten, Øystein, additional, Van Gompel, Jamie J., additional, Vrabec, Jeffrey T., additional, Wanna, George B., additional, and Weisskopf, Peter A., additional

Published
2023
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29. Reduction of sporadic and neurofibromatosis type 2–associated vestibular schwannoma growth in vitro and in vivo after treatment with the c-Jun N-terminal kinase inhibitor AS602801

Author

Dougherty, Mark C., Shibata, Seiji B., Clark, J. Jason, Canady, Franklin J., Yates, Charles W., and Hansen, Marlan R.

Subjects
Laboratory Investigation, General Medicine
Abstract

OBJECTIVE Vestibular schwannomas (VSs) are benign nerve sheath tumors that result from mutation in the tumor suppressor gene NF2, with functional loss of the protein merlin. The authors have previously shown that c-Jun N-terminal kinase (JNK) is constitutively active in human VS cells and plays a central role in their survival by suppressing accumulation of mitochondrial superoxides, implicating JNK inhibitors as a potential systemic treatment for VS. Thus, the authors hypothesized that the adenosine 5ʹ-triphosphate–competitive JNK inhibitor AS602801 would demonstrate antitumor activity in multiple VS models. METHODS Treatment with AS602801 was tested in primary human VS cultures, human VS xenografts, and a genetic mouse model of schwannoma (Postn-Cre;Nf2flox/flox). Primary human VS cell cultures were established from freshly obtained surgical tumor specimens; treatment group media was enriched with AS602801. VS xenograft tumors were established in male athymic nude mice from freshly collected human tumor. Four weeks postimplantation, a pretreatment MRI scan was obtained, followed by 65 days of AS602801 (n = 18) or vehicle control (n = 19) treatment. Posttreatment MRI scans were used to measure final tumor volume. Tumors were then harvested. Finally, Postn-Cre;Nf2flox/flox mice were treated with AS602801 (n = 10) or a vehicle (n = 13) for 65 days. Posttreatment auditory brainstem responses were obtained. Dorsal root ganglia from Postn-Cre;Nf2flox/flox mice were then harvested. In all models, schwannoma identity was confirmed with anti-S100 staining, cell proliferation was measured with the EdU assay, and cell death was measured with terminal deoxynucleotidyl transferase–mediated dUTP nick-end labeling staining. All protocols were approved by the local institutional review board and Institutional Animal Care and Use Committees. RESULTS Treatment with AS602801 decreased cell proliferation and increased apoptosis in primary human VS cultures. The systemic administration of AS602801 in mice with human VS xenografts reduced tumor volume and cell proliferation. Last, the AS602801-treated Postn-Cre;Nf2flox/flox mice demonstrated decreased cell proliferation in glial cells in the dorsal root ganglia. However, AS602801 did not significantly delay hearing loss in Postn-Cre;Nf2flox/flox mice up to 3 months posttreatment. CONCLUSIONS The data suggest that JNK inhibition with AS602801 suppresses growth of sporadic and neurofibromatosis type 2–associated VSs. As such, AS602801 is a potential systemic therapy for VS and warrants further investigation.

Published
2022
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33. Rationale for the Development of a Novel Clinical Grading Scale for Postoperative Facial Nerve Function:Results of a Multidisciplinary International Working Group

Author

Carlson, Matthew L., Lohse, Christine M., Agazzi, Siviero, Babu, Seilesh C., Barker, Frederick G., Barnett, Samuel, Bi, Wenya Linda, Biggs, Nigel, Boahene, Kofi D., Breen, Joseph T., Brown, Kevin D., Cayé-Thomasen, Per, Cosetti, Maura K., Deep, Nicholas L., Dey, Jacob K., Dornhoffer, James R., Forner, David, Gurgel, Richard K., Hansen, Marlan R., Hunter, Jacob B., Kalamarides, Michel, Kim, Irene A., King, Andrew T., Kircher, Matthew L., Lassaletta, Luis, Link, Michael J., Lloyd, Simon K.W., Lund-Johansen, Morten, Marinelli, John P., Matthies, Cordula, Mehta, Vikas, Moore, Eric J., Nassiri, Ashley M., Neff, Brian A., Nelson, Rick F., Olson, Jeffrey J., Patel, Neil S., Celda, Maria Peris, Plitt, Aaron R., Price, Daniel L., Thomas Roland, J., Sweeney, Alex D., Tasche, Kendall K., Tatagiba, Marcos, Tveiten, Oystein, Van Gompel, Jamie J., Vrabec, Jeffrey T., Wanna, George B., Weisskopf, Peter A., Carlson, Matthew L., Lohse, Christine M., Agazzi, Siviero, Babu, Seilesh C., Barker, Frederick G., Barnett, Samuel, Bi, Wenya Linda, Biggs, Nigel, Boahene, Kofi D., Breen, Joseph T., Brown, Kevin D., Cayé-Thomasen, Per, Cosetti, Maura K., Deep, Nicholas L., Dey, Jacob K., Dornhoffer, James R., Forner, David, Gurgel, Richard K., Hansen, Marlan R., Hunter, Jacob B., Kalamarides, Michel, Kim, Irene A., King, Andrew T., Kircher, Matthew L., Lassaletta, Luis, Link, Michael J., Lloyd, Simon K.W., Lund-Johansen, Morten, Marinelli, John P., Matthies, Cordula, Mehta, Vikas, Moore, Eric J., Nassiri, Ashley M., Neff, Brian A., Nelson, Rick F., Olson, Jeffrey J., Patel, Neil S., Celda, Maria Peris, Plitt, Aaron R., Price, Daniel L., Thomas Roland, J., Sweeney, Alex D., Tasche, Kendall K., Tatagiba, Marcos, Tveiten, Oystein, Van Gompel, Jamie J., Vrabec, Jeffrey T., Wanna, George B., and Weisskopf, Peter A.

Abstract

Objective The objective of the current study was to present the results of an international working group survey identifying perceived limitations of existing facial nerve grading scales to inform the development of a novel grading scale for assessing early postoperative facial paralysis that incorporates regional scoring and is anchored in recovery prognosis and risk of associated complications. Study Design Survey. Setting A working group of 48 multidisciplinary clinicians with expertise in skull base, cerebellopontine angle, temporal bone, or parotid gland surgery. Results House-Brackmann grade is the most widely used system to assess facial nerve function among working group members (81%), although more than half (54%) agreed that the system they currently use does not adequately estimate the risk of associated complications, such as corneal injury, and confidence in interrater and intrarater reliability is generally low. Simplicity was ranked as the most important attribute of a novel postoperative facial nerve grading system to increase the likelihood of adoption, followed by reliability and accuracy. There was widespread consensus (91%) that the eye is the most critical facial region to focus on in the early postoperative setting. Conclusions Members were invited to submit proposed grading systems in alignment with the objectives of the working group for subsequent validation. From these data, we plan to develop a simple, clinically anchored, and reproducible staging system with regional scoring for assessing early postoperative facial nerve function after surgery of the skull base, cerebellopontine angle, temporal bone, or parotid gland., Objective The objective of the current study was to present the results of an international working group survey identifying perceived limitations of existing facial nerve grading scales to inform the development of a novel grading scale for assessing early postoperative facial paralysis that incorporates regional scoring and is anchored in recovery prognosis and risk of associated complications. Study Design Survey. Setting A working group of 48 multidisciplinary clinicians with expertise in skull base, cerebellopontine angle, temporal bone, or parotid gland surgery. Results House-Brackmann grade is the most widely used system to assess facial nerve function among working group members (81%), although more than half (54%) agreed that the system they currently use does not adequately estimate the risk of associated complications, such as corneal injury, and confidence in interrater and intrarater reliability is generally low. Simplicity was ranked as the most important attribute of a novel postoperative facial nerve grading system to increase the likelihood of adoption, followed by reliability and accuracy. There was widespread consensus (91%) that the eye is the most critical facial region to focus on in the early postoperative setting. Conclusions Members were invited to submit proposed grading systems in alignment with the objectives of the working group for subsequent validation. From these data, we plan to develop a simple, clinically anchored, and reproducible staging system with regional scoring for assessing early postoperative facial nerve function after surgery of the skull base, cerebellopontine angle, temporal bone, or parotid gland.

Published
2023

35. Contribution of macrophages to intracochlear tissue remodeling responses following cochlear implantation and neural survival

Author

Rahman, Muhammad Taifur, primary, Mostaert, Brain J., additional, Hunger, Bryce, additional, Saha, Utsow, additional, Claussen, Alexander D., additional, Razu, Ibrahim, additional, Farjana, Nasrin, additional, Khan, Nashwaan Ali, additional, Coleman, Sarah, additional, Oleson, Jackob, additional, Kirk, Jonathon, additional, Keiko, Hirose, additional, and Hansen, Marlan R., additional

Published
2023
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36. Neural Correlates of Individual Differences in Speech-in-Noise Performance in a Large Cohort of Cochlear Implant Users

Author

Berger, Joel I., primary, Gander, Phillip E., additional, Kim, Subong, additional, Schwalje, Adam T., additional, Woo, Jihwan, additional, Na, Young-min, additional, Holmes, Ann, additional, Hong, Jean M., additional, Dunn, Camille C., additional, Hansen, Marlan R., additional, Gantz, Bruce J., additional, McMurray, Bob, additional, Griffiths, Timothy D., additional, and Choi, Inyong, additional

Published
2023
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50. Chronic cochlear implantation with and without electric stimulation in a mouse model induces robust cochlear influx of CX3CR1+/GFP macrophages

Author

Claussen, Alexander D., primary, Quevedo, René Vielman, additional, Kirk, Jonathon R., additional, Higgins, Timon, additional, Mostaert, Brian, additional, Rahman, Muhammad Taifur, additional, Oleson, Jacob, additional, Hernandez, Reyna, additional, Hirose, Keiko, additional, and Hansen, Marlan R., additional

Published
2022
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