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Nourmahnad A, Raslan S, Ezeh UC, Rossborough J, Ma R, Anis MM. Association of Sociodemographic Factors on the Presentation and Management of Unilateral Vocal Fold Immobility. Laryngoscope 2024; 134:297-304. [PMID: 37515514 DOI: 10.1002/lary.30917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 06/12/2023] [Accepted: 07/13/2023] [Indexed: 07/31/2023]
Abstract
OBJECTIVE To determine the association of social determinants of health (SDOH) on the presentation and management of unilateral vocal fold immobility (UVFI). METHODS Retrospective chart review of 207 adult UVFI patients evaluated at a tertiary-care hospital between 2018 and 2019 was performed. Sociodemographic factors including gender, median household income, preferred language, and insurance type were recorded. Confounding clinical factors including etiology of UVFI, Voice Handicap Index-10 (VHI-10) score, laryngoscopic findings, and intervention history were extracted from medical records. Multivariable logistic regression was performed using sociodemographic and clinical factors. RESULTS Patient demographics and socioeconomic status were not associated with time to presentation. Patients presenting with glottic insufficiency and UVFI due to malignancy or recurrent laryngeal nerve (RLN) sacrifice had a shorter time to presentation. Higher household income was associated with greater number of interventions (p = 0.02), but neither income nor insurance type affected intervention type or timing. Female patients were less likely to undergo injection medialization laryngoplasty (odds ratio [OR] 0.25, p = 0.005). Older patients were more likely to undergo injection (OR 1.04, p = 0.027). Patients with large glottic gaps (OR 21.2, p = 0.014) and higher VHI-10 scores (OR 1.06, p = 0.047) were more likely to undergo surgery. CONCLUSION Higher household income was associated with greater number of interventions and longer duration of care at a private tertiary-care hospital. RLN sacrifice, known malignancy, and glottic insufficiency significantly reduced the time to presentation. Type of intervention received was a complex interplay of both demographic and clinical factors. Large prospective studies should examine the role of SDOH in the presentation and management of UVFI. LEVEL OF EVIDENCE 4 Laryngoscope, 134:297-304, 2024.
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Affiliation(s)
- Anahita Nourmahnad
- Department of Otolaryngology-Head and Neck Surgery, University of Miami Hospital, Miami, Florida, U.S.A
| | - Shahm Raslan
- Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, U.S.A
| | - Uche C Ezeh
- University of Miami School of Medicine, Miami, Florida, U.S.A
| | | | - Ruixuan Ma
- Division of Biostatistics, Department of Public Health Science, University of Miami Miller School of Medicine, Miami, Florida, U.S.A
| | - Mursalin M Anis
- Department of Otolaryngology-Head and Neck Surgery, University of Miami Hospital, Miami, Florida, U.S.A
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Fantasia RJ, Nourmahnad A, Halpin E, Forman SA. Substituted Cysteine Modification and Protection with n-Alkyl- Methanethiosulfonate Reagents Yields a Precise Estimate of the Distance between Etomidate and a Residue in Activated GABA Type A Receptors. Mol Pharmacol 2021; 99:426-434. [PMID: 33766924 DOI: 10.1124/molpharm.120.000224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/10/2021] [Indexed: 11/22/2022] Open
Abstract
The anesthetic etomidate modulates synaptic α1β2/3γ2 GABAA receptors via binding sites located in transmembrane β+/α- interfaces. Various approaches indicate that etomidate binds near β2/3M286 side chains, including recent cryogenic electron microscopy images in α1β2γ2L receptors under nonphysiologic conditions with ∼3.5-Å resolution. We hypothesized that substituted cysteine modification and protection experiments using variably sized n-alkyl-methanethiosulfonate (MTS) reagents could precisely estimate the distance between bound etomidate and β3M286 side chains in activated functional receptors. Using voltage-clamp electrophysiology in Xenopus oocytes expressing α1β3M286Cγ2L GABAA receptors, we measured functional changes after exposing GABA-activated receptors to n-alkyl-MTS reagents, from methyl-MTS to n-decyl-MTS. Based on previous studies using a large sulfhydryl reagent, we anticipated that cysteine modifications large enough to overlap etomidate sites would cause persistently increased GABA sensitivity and decreased etomidate modulation and that etomidate would hinder these modifications, reducing effects. Based on altered GABA or etomidate sensitivity, ethyl-MTS and larger n-alkyl-MTS reagents modified GABA-activated α1β3M286Cγ2L GABAA receptors. Receptor modification by n-propyl-MTS or larger reagents caused persistently increased GABA sensitivity and decreased etomidate modulation. Receptor-bound etomidate blocked β3M286C modification by n-propyl-MTS, n-butyl-MTS, and n-hexyl-MTS. In contrast, GABA sensitivity was unaltered by receptor exposure to methyl-MTS or ethyl-MTS, and ethyl-MTS modification uniquely increased etomidate modulation. These results reveal a "cut-on" between ethyl-MTS and n-propyl-MTS, from which we infer that -S-(n-propyl) is the smallest β3M286C appendage that overlaps with etomidate sites. Molecular models of the native methionine and -S-ethyl and -S-(n-propyl) modified cysteines suggest that etomidate is located between 1.7 and 3.0 Å from the β3M286 side chain. SIGNIFICANCE STATEMENT: Precise spatial relationships between drugs and their receptor sites are essential for mechanistic understanding and drug development. This study combined electrophysiology, a cysteine substitution, and n-alkyl-methanethiosulfonate modifiers, creating a precise molecular ruler to estimate the distance between a α1β3γ2L GABA type A receptor residue and etomidate bound in the transmembrane β+/α- interface.
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Affiliation(s)
- Ryan J Fantasia
- Beecher-Mallinckrodt Laboratories, Department of Anesthesia Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
| | - Anahita Nourmahnad
- Beecher-Mallinckrodt Laboratories, Department of Anesthesia Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
| | - Elizabeth Halpin
- Beecher-Mallinckrodt Laboratories, Department of Anesthesia Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
| | - Stuart A Forman
- Beecher-Mallinckrodt Laboratories, Department of Anesthesia Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
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Benboujja F, Greenberg M, Nourmahnad A, Rath N, Hartnick C. Evaluation of the Human Vocal Fold Lamina Propria Development Using Optical Coherence Tomography. Laryngoscope 2021; 131:E2558-E2565. [PMID: 33734443 DOI: 10.1002/lary.29516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 02/17/2021] [Accepted: 03/09/2021] [Indexed: 01/21/2023]
Abstract
OBJECTIVES/HYPOTHESIS Identifying distinctive features of the vocal fold (VF) during development could have significant clinical implications for treating voice disorders. This study investigates the structural organization of the VF microanatomy across gender and age groups using optical coherence tomography (OCT). STUDY DESIGN Prospective clinical trial. MATERIALS AND METHODS In vivo OCT images were acquired from 97 patients (58 males and 39 females) aged between 6 weeks and 27 years. All patients showed no signs of vocal fold pathology on endoscopy. Morphological features were extracted from OCT images and statistically compared between age groups. This study was performed at Massachusetts Eye and Ear between 2017 and 2019. RESULTS All OCT acquisitions show a stratified microanatomy across age groups, even in newborns suggesting the presence of a superficial lamina propria (SLP) at birth. Furthermore, the optical scattering in the VF lamina propria changes according to age, suggesting subepithelial maturation. Although the epithelium thickness was relatively constant across age groups, the SLP showed a significant linear relationship between age and thickness (P = .016). Furthermore, a significant difference (P = .002) in SLP thickness was found between young adult males and females. The overall thickness of the entire mucosa did not change significantly with age. CONCLUSION OCT is a noninvasive imaging modality capable of providing quantitative morphological features to describe the VF development. A stratified structure can be observed in OCT from newborns to young adults. Further investigations could combine OCT, acoustic measurements, and molecular sensitive techniques to provide a complete interpretation of the VF development. LEVEL OF EVIDENCE NA Laryngoscope, 131:E2558-E2565, 2021.
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Affiliation(s)
- Fouzi Benboujja
- Harvard Medical School, Department of Otolaryngology, Massachusetts Eye and Ear, Boston, Massachusetts, U.S.A
| | - Max Greenberg
- Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, U.S.A
| | - Anahita Nourmahnad
- Harvard Medical School, Department of Otolaryngology, Massachusetts Eye and Ear, Boston, Massachusetts, U.S.A
| | - Nicholas Rath
- Departments of Biomedical Engineering and Mechanical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, U.S.A
| | - Christopher Hartnick
- Harvard Medical School, Department of Otolaryngology, Massachusetts Eye and Ear, Boston, Massachusetts, U.S.A
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Workman AD, Soylu S, Kamani D, Nourmahnad A, Kyriazidis N, Saade R, Ren Y, Wirth L, Faquin WC, Onenerk AM, Nikiforov YE, Al-Qurayshi Z, Kandil E, Kloos RT, Eldeiry L, Lubitz C, Stathatos N, Randolph GW. Limitations of preoperative cytology for medullary thyroid cancer: Proposal for improved preoperative diagnosis for optimal initial medullary thyroid carcinoma specific surgery. Head Neck 2020; 43:920-927. [PMID: 33269526 DOI: 10.1002/hed.26550] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 10/13/2020] [Accepted: 11/10/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Preoperative diagnosis of medullary thyroid carcinoma (MTC) is often difficult, given the poor sensitivity of fine-needle aspiration (FNA) cytology for MTC. This study investigates this issue and presents recommendations for improving preoperative diagnostic paradigms in MTC cases. DESIGN/METHOD Histopathologically confirmed MTC patients with preoperative cytologic assessment of index nodules were enrolled. FNA diagnosis, final pathology, and surgery details were collected. RESULTS Out of 71 patients, 49 (69%) were diagnosed by FNA as either definitive MTC (35, 49%) or suspected MTC (14, 20%) and 22 (31%) patients had no indication of MTC on FNA. CONCLUSION In a tertiary-care setting, one-third of subjects had an FNA interpretation that did not suggest the possibility of MTC. The limitations of preoperative diagnosis are especially problematic for MTC as they can cause delayed or incomplete treatment. Additional testing is proposed to improve preoperative diagnosis and surgical care of MTC patients.
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Affiliation(s)
- Alan D Workman
- Division of Thyroid and Parathyroid Surgery, Department of Otolaryngology, Massachusetts Eye and Ear and Harvard Medical School, Boston, Massachusetts, USA
| | - Selen Soylu
- Division of Thyroid and Parathyroid Surgery, Department of Otolaryngology, Massachusetts Eye and Ear and Harvard Medical School, Boston, Massachusetts, USA
| | - Dipti Kamani
- Division of Thyroid and Parathyroid Surgery, Department of Otolaryngology, Massachusetts Eye and Ear and Harvard Medical School, Boston, Massachusetts, USA
| | | | - Natalia Kyriazidis
- Division of Thyroid and Parathyroid Surgery, Department of Otolaryngology, Massachusetts Eye and Ear and Harvard Medical School, Boston, Massachusetts, USA
| | - Ryan Saade
- Division of Thyroid and Parathyroid Surgery, Department of Otolaryngology, Massachusetts Eye and Ear and Harvard Medical School, Boston, Massachusetts, USA
| | - Yin Ren
- Division of Thyroid and Parathyroid Surgery, Department of Otolaryngology, Massachusetts Eye and Ear and Harvard Medical School, Boston, Massachusetts, USA
| | - Lori Wirth
- Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - William C Faquin
- Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Ayşe M Onenerk
- Department of Pathology, Haydarpaşa Numune Training and Research Hospital, Istanbul, Turkey
| | - Yuri E Nikiforov
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
| | - Zaid Al-Qurayshi
- Department of Otolaryngology - Head and Neck Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Emad Kandil
- Department of Surgery, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - Richard T Kloos
- Department of Medical Affairs, Veracyte Inc., South San Francisco, California, USA
| | - Leslie Eldeiry
- Harvard Vanguard Medical Associates, Atrius Health, Boston, Massachusetts, USA
| | - Carrie Lubitz
- Department of Surgery, Massachusetts General Hospital, Boston, Massachusetts, USA.,Institute for Technology Assessment, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Nikolaos Stathatos
- Thyroid Unit, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Gregory W Randolph
- Division of Thyroid and Parathyroid Surgery, Department of Otolaryngology, Massachusetts Eye and Ear and Harvard Medical School, Boston, Massachusetts, USA.,Division of Surgical Oncology, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
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5
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Shay D, Scheffenbichler FT, Kelly BJ, Lihn AL, Deng H, Nourmahnad A, Xu X, Houle TT, Eikermann M, Forman SA. Effects of Anticholinesterase Reversal Under General Anesthesia on Postoperative Cardiovascular Complications: A Retrospective Cohort Study. Anesth Analg 2020; 130:685-695. [PMID: 30896593 DOI: 10.1213/ane.0000000000004099] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND The anticholinesterase neostigmine and the muscarinic inhibitor glycopyrrolate are frequently coadministered for the reversal of neuromuscular blockade. This practice can precipitate severe bradycardia or tachycardia, but whether it affects the incidence of cardiovascular complications remains unclear. We hypothesized that anticholinesterase reversal with neostigmine and glycopyrrolate versus no anticholinesterase reversal increases the risk of postoperative cardiovascular complications among adult patients undergoing noncardiac surgery with general anesthesia. METHODS We conducted a prespecified retrospective analysis of hospital registry data from a major health care network for patients undergoing surgery with general anesthesia from January 2007 to December 2015. The primary outcome was a composite of cardiac dysrhythmia, acute heart failure, transient ischemic attack, ischemic stroke, and acute myocardial infarction within 30 days after surgery. We performed sensitivity analyses in subgroups and propensity score adjustment and explored the association between exposure and outcome in subgroups of patients with high risk of cardiovascular complications. RESULTS Of the 98,147 cases receiving neuromuscular blockade, 73,181 (74.6%) received neostigmine and glycopyrrolate, while 24,966 (25.4%) did not. A total of 5612 patients (7.7%) in the anticholinesterase reversal group and 1651 (6.6%) in the control group (P < .001) experienced the primary outcome. After adjustment for clinical covariates, neostigmine and glycopyrrolate exposure was significantly associated in a dose-dependent fashion (P for trend <.001, respectively) with tachycardia (adjusted odds ratio = 2.1 [95% CI, 1.97-2.23]; P < .001) and bradycardia (adjusted odds ratio = 2.84 [95% CI, 2.49-3.24]; P < .001) but not with postoperative cardiovascular complications (adjusted odds ratio = 1.03 [95% CI, 0.97-1.1]; P = .33). We identified a significant effect modification of anticholinesterase reversal by high age, high-risk surgery, and history of atrial fibrillation (P for interaction = .002, .001, and .02, respectively). By using linear combinations of main effect and exposure-risk interaction terms, we detected significant associations between anticholinesterase reversal and cardiovascular complications toward a higher vulnerability in these patient subgroups. CONCLUSIONS Neuromuscular blockade reversal with neostigmine and glycopyrrolate was associated with an increased incidence of intraoperative tachycardia and bradycardia but not with 30-day postoperative cardiovascular complications. Exploratory analyses suggest that a high postoperative cardiovascular complication risk profile may modify the effects of anticholinesterase reversal toward clinical relevance.
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Affiliation(s)
- Denys Shay
- From the Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Flora T Scheffenbichler
- From the Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Barry J Kelly
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Anne-Louise Lihn
- From the Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Hao Deng
- From the Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Anahita Nourmahnad
- From the Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Xinling Xu
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Timothy T Houle
- From the Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Matthias Eikermann
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
- Klinik für Anästhesiologie und Intensivmedizin, Universitätsklinikum Essen, Essen, Germany
| | - Stuart A Forman
- From the Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
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6
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Chen JX, Nourmahnad A, O'Malley J, Reinshagen K, Nadol JB, Quesnel AM. Otopathology in CHARGE syndrome. Laryngoscope Investig Otolaryngol 2020; 5:157-162. [PMID: 32128443 PMCID: PMC7042646 DOI: 10.1002/lio2.347] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/18/2019] [Accepted: 12/24/2019] [Indexed: 11/18/2022] Open
Abstract
Postmortem temporal bone computed tomography (CT) and histopathologic findings in an infant with CHARGE syndrome revealed bilateral cochleovestibular hypoplasia, including cochlear pathology relevant to cochlear implant candidacy. Both ears had absence of the superior semicircular canals (SCCs), severely hypoplastic posterior SCCs, and hypoplastic (right ear) or absent (left ear) lateral SCCs seen on CT and histopathology. Histopathology further revealed the absence of all SCC ampullae except the right lateral SCC ampulla and atrophic vestibular neuroepithelium in the saccule and utricle bilaterally. The right cochlea consisted of a basal turn with patent round window, and malformed middle turn (type IV cochlear hypoplasia), with a small internal auditory canal (IAC) but near normal cochlear nerve aperture (fossette). Quantification of spiral ganglion neurons (SGNs) on histologic sections revealed a reduced SGN population (35% of normal for age), but this ear would still have likely achieved benefit from a cochlear implant based on this population. The left cochlea consisted of only a basal turn with patent round window (type III cochlear hypoplasia) with a small IAC and very small cochlear nerve aperture. Notably, histology revealed that there were no SGNs in the cochlea, and therefore, this ear would not have been a good candidate for cochlear implantation. Level of evidence: IV.
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Affiliation(s)
- Jenny X Chen
- Department of Otolaryngology Harvard Medical School Boston Massachusetts
| | - Anahita Nourmahnad
- Department of Otolaryngology Harvard Medical School Boston Massachusetts
| | - Jennifer O'Malley
- Department of Otolaryngology Harvard Medical School Boston Massachusetts
| | | | - Joseph B Nadol
- Department of Otolaryngology Harvard Medical School Boston Massachusetts
- Otopathology Laboratory Massachusetts Eye and Ear Boston Massachusetts
| | - Alicia M Quesnel
- Department of Otolaryngology Harvard Medical School Boston Massachusetts
- Otopathology Laboratory Massachusetts Eye and Ear Boston Massachusetts
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7
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Nourmahnad A, Benboujja F, Hartnick CJ. Using intraoperative optical coherence tomography to image pediatric unilateral vocal fold paralysis. Int J Pediatr Otorhinolaryngol 2019; 121:72-75. [PMID: 30877978 DOI: 10.1016/j.ijporl.2019.02.039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 02/22/2019] [Accepted: 02/22/2019] [Indexed: 10/27/2022]
Abstract
OBJECTIVES Unilateral vocal fold paralysis (UVFP) impairs communication and reduces academic performance and social interactions in children. Deciding between temporary, permanent, or potentially destructive surgical interventions can be challenging, as there currently exists no reliable means of predicting vocal fold recovery or assessing the presence of vocal fold atrophy. Regarding vocal fold atrophy, optical coherence tomography (OCT) has been shown to be an appealing non-invasive alternative for accessing vocal fold structures. This study describes UVFP microanatomy and identifies possible vocal fold atrophy using OCT. METHODS Three UVFP patients (ages 1, 11, and 17 years) underwent bilateral OCT imaging using a handheld probe while under general anesthesia for direct laryngoscopy, and the laryngoscopic images were compared with images obtained from OCT. Structural morphological features were extracted and compared to a healthy patients' cohort. RESULTS While endoscopy showed no evidence of vocal fold atrophy in two of three cases, OCT images revealed distinct differences between the lamina propria of the paralyzed and functional vocal folds in all patients. In two cases, the paralyzed vocal fold morphology was similar to a healthy patient at the age of nerve injury. The third case exhibited extensive scarring in the lamina propria of the paralyzed vocal fold. CONCLUSION This pilot study characterizes and compares vocal fold microanatomy in three UVFP patients. In most cases, lamina propria development halted at the age of paralysis, suggesting that lamina propria maturation may be dependent on vocal fold functionality. OCT shows potential to aid UVFP assessment and treatment decisions by evaluating the presence of atrophy.
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Affiliation(s)
| | - Fouzi Benboujja
- Department of Otolaryngology-Head and Neck Surgery, Massachusetts Eye and Ear Infirmary, Boston, MA, USA
| | - Christopher J Hartnick
- Department of Otolaryngology-Head and Neck Surgery, Massachusetts Eye and Ear Infirmary, Boston, MA, USA
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8
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Szabo A, Nourmahnad A, Halpin E, Forman SA. Monod-Wyman-Changeux Allosteric Shift Analysis in Mutant α1 β3 γ2L GABA A Receptors Indicates Selectivity and Crosstalk among Intersubunit Transmembrane Anesthetic Sites. Mol Pharmacol 2019; 95:408-417. [PMID: 30696720 DOI: 10.1124/mol.118.115048] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/19/2019] [Indexed: 12/28/2022] Open
Abstract
Propofol, etomidate, and barbiturate anesthetics are allosteric coagonists at pentameric α1β3γ2 GABAA receptors, modulating channel activation via four biochemically established intersubunit transmembrane pockets. Etomidate selectively occupies the two β +/α - pockets, the barbiturate photolabel R-5-allyl-1-methyl-5-(m-trifluoromethyl-diazirynylphenyl) barbituric acid (R-mTFD-MPAB) occupies homologous α +/β - and γ +/β - pockets, and propofol occupies all four. Functional studies of mutations at M2-15' or M3-36' loci abutting these pockets provide conflicting results regarding their relative contributions to propofol modulation. We electrophysiologically measured GABA-dependent channel activation in α1β3γ2L or receptors with single M2-15' (α1S270I, β3N265M, and γ2S280W) or M3-36' (α1A291W, β3M286W, and γ2S301W) mutations, in the absence and presence of equipotent clinical range concentrations of etomidate, R-mTFD-MPAB, and propofol. Estimated open probabilities were calculated and analyzed using global two-state Monod-Wyman-Changeux models to derive log(d) parameters proportional to anesthetic-induced channel modulating energies (where d is the allosteric anesthetic shift factor). All mutations reduced the log(d) values for anesthetics occupying both abutting and nonabutting pockets. The Δlog(d) values [log(d, mutant) - log(d, wild type)] for M2-15' mutations abutting an anesthetic's biochemically established binding sites were consistently larger than the Δlog(d) values for nonabutting mutations, although this was not true for the M3-36' mutant Δlog(d) values. The sums of the anesthetic-associated Δlog(d) values for sets of M2-15' or M3-36' mutations were all much larger than the wild-type log(d) values. Mutant Δlog(d) values qualitatively reflect anesthetic site occupancy patterns. However, the lack of Δlog(d) additivity undermines quantitative comparisons of distinct site contributions to anesthetic modulation because the mutations impaired both abutting anesthetic binding effects and positive cooperativity between anesthetic binding sites.
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Affiliation(s)
- Andrea Szabo
- Beecher-Mallinckrodt Laboratories, Department of Anesthesia Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
| | - Anahita Nourmahnad
- Beecher-Mallinckrodt Laboratories, Department of Anesthesia Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
| | - Elizabeth Halpin
- Beecher-Mallinckrodt Laboratories, Department of Anesthesia Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
| | - Stuart A Forman
- Beecher-Mallinckrodt Laboratories, Department of Anesthesia Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
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9
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McGill M, Raol N, Gipson KS, Bowe SN, Fulk-Logan J, Nourmahnad A, Chung JY, Whalen MJ, Kaplan DL, Hartnick CJ. Preclinical assessment of resorbable silk splints for the treatment of pediatric tracheomalacia. Laryngoscope 2018; 129:2189-2194. [PMID: 30408198 DOI: 10.1002/lary.27540] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 08/03/2018] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Tracheomalacia is characterized by weakness of the tracheal wall resulting in dynamic airway collapse during respiration; severe cases often require surgical intervention. Off-label external splinting with degradable implants has been reported in humans; however, there remains a need to develop splints with tunable mechanical properties and degradation profiles for the pediatric population. The objective of this pilot study is to assess the safety and efficacy of silk fibroin-based splints in a clinically relevant preclinical model of tracheomalacia. METHODS Silk splints were evaluated in a surgically induced model of severe tracheomalacia in N = 3 New Zealand white rabbits for 17, 24, and 31 days. An image-based assay was developed to quantify the dynamic change in airway area during spontaneous respiration, and histopathology was used to study the surrounding tissue response. RESULTS The average change in area in the native trachea was 23% during spontaneous respiration; surgically induced tracheomalacia resulted in a significant increase to 86% (P < 0.001). The average change in airway area after splint placement was reduced at all terminal time points (17, 24, and 31 days postimplantation), indicating a clinical improvement, and was not statistically different than the native trachea. Histopathology showed a localized inflammatory reaction characterized by neutrophils, eosinophils, and mononuclear cells, with early signs suggestive of fibrosis at the splint and tissue interface. CONCLUSION This pilot study indicates that silk fibroin splints are well tolerated and efficacious in a rabbit model of severe tracheomalacia, with marked reduction in airway collapse following implantation and good tolerability over the studied time course. LEVEL OF EVIDENCE NA Laryngoscope, 129:2189-2194, 2019.
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Affiliation(s)
- Meghan McGill
- Department of Biomedical Engineering, Tufts University, Medford
| | - Nikhila Raol
- Department of Otolaryngology-Head and Neck Surgery, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.,the Department of Otolaryngology-Head and Neck Surgery, Emory University School of Medicine, Atlanta, Georgia, U.S.A
| | - Kevin S Gipson
- Department of Pediatrics, Division of Pediatric Pulmonology the Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts
| | - Sarah N Bowe
- Department of Otolaryngology-Head and Neck Surgery, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
| | | | - Anahita Nourmahnad
- Department of Otolaryngology-Head and Neck Surgery, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.,Harvard Medical School, Boston, Massachusetts
| | - Joon Yong Chung
- Department of Pediatrics, Division of Pediatric Pulmonology the Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts
| | - Michael J Whalen
- Department of Pediatrics, Division of Pediatric Pulmonology the Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts
| | - David L Kaplan
- Department of Biomedical Engineering, Tufts University, Medford
| | - Christopher J Hartnick
- Department of Otolaryngology-Head and Neck Surgery, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
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Maldifassi MC, Baur R, Pierce D, Nourmahnad A, Forman SA, Sigel E. Novel positive allosteric modulators of GABAA receptors with anesthetic activity. Sci Rep 2016; 6:25943. [PMID: 27198062 PMCID: PMC4873749 DOI: 10.1038/srep25943] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 04/25/2016] [Indexed: 01/08/2023] Open
Abstract
GABAA receptors are the main inhibitory neurotransmitter receptors in the brain and are targets for numerous clinically important drugs such as benzodiazepines, anxiolytics and anesthetics. We previously identified novel ligands of the classical benzodiazepine binding pocket in α1β2γ2 GABAA receptors using an experiment-guided virtual screening (EGVS) method. This screen also identified novel ligands for intramembrane low affinity diazepam site(s). In the current study we have further characterized compounds 31 and 132 identified with EGVS as well as 4-O-methylhonokiol. We investigated the site of action of these compounds in α1β2γ2 GABAA receptors expressed in Xenopus laevis oocytes using voltage-clamp electrophysiology combined with a benzodiazepine site antagonist and transmembrane domain mutations. All three compounds act mainly through the two β+/α− subunit transmembrane interfaces of the GABAA receptors. We then used concatenated receptors to dissect the involvement of individual β+/α− interfaces. We further demonstrated that these compounds have anesthetic activity in a small aquatic animal model, Xenopus laevis tadpoles. The newly identified compounds may serve as scaffolds for the development of novel anesthetics.
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Affiliation(s)
- Maria C Maldifassi
- Institute of Biochemistry and Molecular Medicine, University of Bern, CH-3012 Bern, Switzerland
| | - Roland Baur
- Institute of Biochemistry and Molecular Medicine, University of Bern, CH-3012 Bern, Switzerland
| | - David Pierce
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, 02114 Massachusetts
| | - Anahita Nourmahnad
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, 02114 Massachusetts
| | - Stuart A Forman
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, 02114 Massachusetts
| | - Erwin Sigel
- Institute of Biochemistry and Molecular Medicine, University of Bern, CH-3012 Bern, Switzerland
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Nourmahnad A, Smith MD, Zeller M, Ferrence GM, Schrier J, Norquist AJ. Role of Noncovalent Interactions in Vanadium Tellurite Chain Connectivities. Inorg Chem 2015; 54:694-703. [DOI: 10.1021/ic502753e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anahita Nourmahnad
- Department
of Chemistry, Haverford College, Haverford, Pennsylvania 19041, United States
| | - Matthew D. Smith
- Department
of Chemistry, Haverford College, Haverford, Pennsylvania 19041, United States
| | - Matthias Zeller
- Department
of Chemistry, Youngstown State University, Youngstown, Ohio 44555, United States
| | - Gregory M. Ferrence
- Department
of Chemistry, Illinois State University, Normal, Illinois 61790, United States
| | - Joshua Schrier
- Department
of Chemistry, Haverford College, Haverford, Pennsylvania 19041, United States
| | - Alexander J. Norquist
- Department
of Chemistry, Haverford College, Haverford, Pennsylvania 19041, United States
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12
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Olshansky JH, Wiener KJ, Smith MD, Nourmahnad A, Charles MJ, Zeller M, Schrier J, Norquist AJ. Formation principles for vanadium selenites: the role of pH on product composition. Inorg Chem 2014; 53:12027-35. [PMID: 25365238 DOI: 10.1021/ic501736r] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A series of organically templated vanadium selenites has been prepared under mild hydrothermal conditions. Single crystals of [C5H14N2][(VO)3(SeO3)2(HSeO3)4], [C5H14N2][VO(SeO3)2], [(R)-C5H14N2][(VO)3(SeO3)2(HSeO3)4], and [(S)-C5H14N2][(VO)3(SeO3)2(HSeO3)4] were grown from VOSO4, SeO2, and 2-methylpiperazine. Controlling the initial pH of the reaction mixture allows for one to select between the compounds found in the VOSO4/SeO2/2-methylpiperazine system, as the solution pH directly affects the relative ratio of the HSeO3(-) and SeO3(2-) concentrations. Moreover, partial resolution of racemic 2-methylpiperazine is observed in [C5H14N2][(VO)3(SeO3)2(HSeO3)4], which is understood through the use of a one-dimensional Ising model. The use of enantiomerically pure 2-methylpiperazine results in fully ordered and fully resolved structures.
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Affiliation(s)
- Jacob H Olshansky
- Department of Chemistry, Haverford College , Haverford, Pennsylvania 19041, United States
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