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Steinhardt CR, Mitchell DE, Cullen KE, Fridman GY. Pulsatile electrical stimulation creates predictable, correctable disruptions in neural firing. Nat Commun 2024; 15:5861. [PMID: 38997274 PMCID: PMC11245474 DOI: 10.1038/s41467-024-49900-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 06/21/2024] [Indexed: 07/14/2024] Open
Abstract
Electrical stimulation is a key tool in neuroscience, both in brain mapping studies and in many therapeutic applications such as cochlear, vestibular, and retinal neural implants. Due to safety considerations, stimulation is restricted to short biphasic pulses. Despite decades of research and development, neural implants lead to varying restoration of function in patients. In this study, we use computational modeling to provide an explanation for how pulsatile stimulation affects axonal channels and therefore leads to variability in restoration of neural responses. The phenomenological explanation is transformed into equations that predict induced firing rate as a function of pulse rate, pulse amplitude, and spontaneous firing rate. We show that these equations predict simulated responses to pulsatile stimulation with a variety of parameters as well as several features of experimentally recorded primate vestibular afferent responses to pulsatile stimulation. We then discuss the implications of these effects for improving clinical stimulation paradigms and electrical stimulation-based experiments.
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Affiliation(s)
- Cynthia R Steinhardt
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA.
- Center for Theoretical Neuroscience, Columbia University, New York, NY, USA.
| | - Diana E Mitchell
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC, Canada
| | - Kathleen E Cullen
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA
- Department of Otolaryngology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Gene Y Fridman
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA
- Department of Otolaryngology, Johns Hopkins School of Medicine, Baltimore, MD, USA
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Pollastri F, Giannoni B, Marcelli V, Spadavecchia G, Pecci R. Bone-Anchored Hearing Aid Effects on Vestibular Function: A Preliminary Report. Audiol Res 2024; 14:386-400. [PMID: 38666904 PMCID: PMC11047723 DOI: 10.3390/audiolres14020033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 03/31/2024] [Accepted: 04/18/2024] [Indexed: 04/29/2024] Open
Abstract
OBJECTIVE Cochlear receptors are sensitive to vibratory stimuli. Based on this sensibility, bone-anchored hearing aids have been introduced to correct unilateral or bilateral conductive or mixed hearing loss and unilateral deafness. The vestibular system is also sensitive to the vibratory stimulus and this type of response is used in clinics to test its functionality. Being aware of this double separated sensibility, we wondered whether bone vibration, which activates the acoustic receptors of patients with bone conduction aids, can also influence the functionality of the vestibular system. METHODS To this end, we recruited 12 patients with a bone-anchored hearing aid and evaluated their vestibular function with and without an activated vibratory acoustic device. RESULTS Our results show that the vibratory stimulus delivered by the bone conduction aid also reaches and stimulates the vestibular receptors; this stimulation is evidenced by the appearance or modification of some nystagmus findings during bedside vestibular testing. Despite this, none of these patients complained of dizziness or vertigo during prosthesis use. Nystagmus that appeared or changed during acoustic vibratory stimulation through the prosthesis was almost all predominantly horizontal, unidirectional with respect to gaze or body position, inhibited by fixation, and most often consistent with vestibular function tests indicating peripheral vestibular damage. CONCLUSIONS The findings of sound-evoked nystagmus seem to indicate peripheral rather than central vestibular activation. The occurrence of some predominantly horizontal and high-frequency induced nystagmus seems to attribute the response mainly to the utricle and lateral semicircular canal.
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Affiliation(s)
- Federica Pollastri
- Unit of Audiology, Careggi University Hospital, Largo Brambilla 3, 50134 Florence, Italy; (B.G.); (G.S.); (R.P.)
| | - Beatrice Giannoni
- Unit of Audiology, Careggi University Hospital, Largo Brambilla 3, 50134 Florence, Italy; (B.G.); (G.S.); (R.P.)
- Department of Neuroscience, Psychology, Drug’s Area and Child’s Health, University of Florence, 50134 Florence, Italy
| | | | - Giulia Spadavecchia
- Unit of Audiology, Careggi University Hospital, Largo Brambilla 3, 50134 Florence, Italy; (B.G.); (G.S.); (R.P.)
| | - Rudi Pecci
- Unit of Audiology, Careggi University Hospital, Largo Brambilla 3, 50134 Florence, Italy; (B.G.); (G.S.); (R.P.)
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Pastras CJ, Curthoys IS. Vestibular Testing-New Physiological Results for the Optimization of Clinical VEMP Stimuli. Audiol Res 2023; 13:910-928. [PMID: 37987337 PMCID: PMC10660708 DOI: 10.3390/audiolres13060079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 11/05/2023] [Accepted: 11/07/2023] [Indexed: 11/22/2023] Open
Abstract
Both auditory and vestibular primary afferent neurons can be activated by sound and vibration. This review relates the differences between them to the different receptor/synaptic mechanisms of the two systems, as shown by indicators of peripheral function-cochlear and vestibular compound action potentials (cCAPs and vCAPs)-to click stimulation as recorded in animal studies. Sound- and vibration-sensitive type 1 receptors at the striola of the utricular macula are enveloped by the unique calyx afferent ending, which has three modes of synaptic transmission. Glutamate is the transmitter for both cochlear and vestibular primary afferents; however, blocking glutamate transmission has very little effect on vCAPs but greatly reduces cCAPs. We suggest that the ultrafast non-quantal synaptic mechanism called resistive coupling is the cause of the short latency vestibular afferent responses and related results-failure of transmitter blockade, masking, and temporal precision. This "ultrafast" non-quantal transmission is effectively electrical coupling that is dependent on the membrane potentials of the calyx and the type 1 receptor. The major clinical implication is that decreasing stimulus rise time increases vCAP response, corresponding to the increased VEMP response in human subjects. Short rise times are optimal in human clinical VEMP testing, whereas long rise times are mandatory for audiometric threshold testing.
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Affiliation(s)
- Christopher J. Pastras
- Faculty of Science and Engineering, School of Engineering, Macquarie University, Sydney, NSW 2109, Australia;
| | - Ian S. Curthoys
- Vestibular Research Laboratory, School of Psychology, The University of Sydney, Sydney, NSW 2006, Australia
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Janky K, Steyger PS. Mechanisms and Impact of Aminoglycoside-Induced Vestibular Deficits. Am J Audiol 2023; 32:746-760. [PMID: 37319406 PMCID: PMC10721243 DOI: 10.1044/2023_aja-22-00199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 01/26/2023] [Accepted: 03/06/2023] [Indexed: 06/17/2023] Open
Abstract
PURPOSE Acquired vestibulotoxicity from hospital-prescribed medications such as aminoglycoside antibiotics affects as many as 40,000 people each year in North America. However, there are no current federally approved drugs to prevent or treat the debilitating and permanent loss of vestibular function caused by bactericidal aminoglycoside antibiotics. This review will cover our current understanding of the impact of, and mechanisms underlying, aminoglycoside-induced vestibulotoxicity and highlight the gaps in our knowledge that remain. CONCLUSIONS Aminoglycoside-induced vestibular deficits have long-term impacts on patients across the lifespan. Additionally, the prevalence of aminoglycoside-induced vestibulotoxicity appears to be greater than cochleotoxicity. Thus, monitoring for vestibulotoxicity should be independent of auditory monitoring and encompass patients of all ages from young children to older adults before, during, and after aminoglycoside therapy.
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Affiliation(s)
- Kristen Janky
- Department of Audiology, Boys Town National Research Hospital, Omaha, NE
| | - Peter S. Steyger
- Bellucci Translational Hearing Center, Creighton University, Omaha, NE
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Pastras CJ, Curthoys IS, Rabbitt RD, Brown DJ. Using macular velocity measurements to relate parameters of bone conduction to vestibular compound action potential responses. Sci Rep 2023; 13:10204. [PMID: 37353559 PMCID: PMC10290084 DOI: 10.1038/s41598-023-37102-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 06/15/2023] [Indexed: 06/25/2023] Open
Abstract
To examine mechanisms responsible for vestibular afferent sensitivity to transient bone conducted vibration, we performed simultaneous measurements of stimulus-evoked vestibular compound action potentials (vCAPs), utricular macula velocity, and vestibular microphonics (VMs) in anaesthetized guinea pigs. Results provide new insights into the kinematic variables of transient motion responsible for triggering mammalian vCAPs, revealing synchronized vestibular afferent responses are not universally sensitive to linear jerk as previously thought. For short duration stimuli (< 1 ms), the vCAP increases magnitude in close proportion to macular velocity and temporal bone (linear) acceleration, rather than other kinematic elements. For longer duration stimuli, the vCAP magnitude switches from temporal bone acceleration sensitive to linear jerk sensitive while maintaining macular velocity sensitivity. Frequency tuning curves evoked by tone-burst stimuli show vCAPs increase in proportion to onset macular velocity, while VMs increase in proportion to macular displacement across the entire frequency bandwidth tested between 0.1 and 2 kHz. The subset of vestibular afferent neurons responsible for synchronized firing and vCAPs have been shown previously to make calyceal synaptic contacts with type I hair cells in the striolar region of the epithelium and have irregularly spaced inter-spike intervals at rest. Present results provide new insight into mechanical and neural mechanisms underlying synchronized action potentials in these sensitive afferents, with clinical relevance for understanding the activation and tuning of neurons responsible for driving rapid compensatory reflex responses.
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Affiliation(s)
- Christopher J Pastras
- Faculty of Science and Engineering, School of Engineering, Macquarie University, Sydney, NSW, 2109, Australia.
- School of Medical Sciences, The University of Sydney, Sydney, NSW, 2050, Australia.
| | - Ian S Curthoys
- Vestibular Research Laboratory, School of Psychology, The University of Sydney, Sydney, NSW, 2050, Australia
| | - Richard D Rabbitt
- Departments of Biomedical Engineering, Otolaryngology and Neuroscience Program, University of Utah, Salt Lake City, UT, 84112, USA
| | - Daniel J Brown
- School of Pharmacy and Biomedical Sciences, Curtin University, Bentley, WA, 6102, Australia
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Identification of Neural Mechanisms in First Single-Sweep Analysis in oVEMPs and Novel Normative Data. J Clin Med 2022; 11:jcm11237124. [PMID: 36498697 PMCID: PMC9738122 DOI: 10.3390/jcm11237124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/21/2022] [Accepted: 11/28/2022] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Bone-conducted (BC) VEMPs provide important tools for measuring otolith function. However, two major drawbacks of this method are encountered in clinical practice-small n10 amplitude and averaging technique. In this study, we present the results of a new VEMP setup measuring technique combined with a novel single-sweep analysis. METHODS The study included BC oVEMP data from 92 participants for the evaluation of normative data using a novel analysis technique. For evaluating test-retest reliability, the intraclass correlation coefficient (ICC) was used. RESULTS We found significant n10 amplitude differences in single-sweep analyses after the first and second measurements. Thereby, mathematical analyses of the head movement did not show any differences in the first or second measurements. The normative n10 amplitude was 20.66 µV with an asymmetric ratio (AR) of 7%. The new value of late shift difference (LSD) was 0.01 ms. The test retest-reliability showed good to excellent ICC results in 9 out of 10 measurements. CONCLUSIONS Our results support a phenomenon in single-sweep analysis of the first stimuli independent of head movement and signal morphology. Furthermore, the values obtained with the new measurement method appear to be more sensitive and may allow an extended diagnostic range due to the new parameter LSD.
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张 姝, 黎 志, 李 凌, 曾 祥. [An analyzation on the characterization of frequency tuning of vestibular evoked myogenic potential in patients with unilateral vestibular hypofunction]. LIN CHUANG ER BI YAN HOU TOU JING WAI KE ZA ZHI = JOURNAL OF CLINICAL OTORHINOLARYNGOLOGY, HEAD, AND NECK SURGERY 2022; 36:702-706. [PMID: 36036072 PMCID: PMC10127623 DOI: 10.13201/j.issn.2096-7993.2022.09.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Indexed: 06/15/2023]
Abstract
Objective: To explore the value of adding 1 kHz cervical vestibular evoked myogenic potential(cVEMP) and ocular vestibular evoked myogenic potential(oVEMP) in the auxiliary diagnosis of unilateral vestibular hypofunction. Methods:A retrospective analysis of 84 patients with unilateral vestibular hypofunction receiving two or more vestibular function tests was conducted,29 cases of unilateral Ménière's disease, 27 cases of benign paroxysmal positional vertigo (BPPV), 8 cases of idiopathic sudden sensorineural hearing loss (ISSHL) with vertigo, and 20 cases of ISSHL without vertigo were included. SPSS 25.0 software was used for statistical analysis to observe the difference of frequency amplitude ratio (FAR) at 500 Hz/1 kHz of cVEMP and oVEMP between the experimental and control groups. Results:①The cVEMP elicitation rates were 95.24% (80/84) and 98.81% (83/84) for 500 Hz and 1 kHz, respectively; and the oVEMP elicitation rates were 78.57% (66/84) and 91.67% (77/84) for 500 Hz and 1 kHz, respectively. ②Except for the lateral difference of FAR in oVEMP of the posterior semicircular canal BPPV group and cVEMP of the horizontal semicircular canal BPPV group (P<0.05), no significant lateral difference was observed in the other disease groups (P>0.05). Conclusion:In patients with unilateral vestibular hypofunction, cVEMP and oVEMP showed different frequency tuning changes in different semicircular canal BPPV groups. Additionally, 1 kHz cVEMP and oVEMP as regular stimulation frequencies in clinical test, which has certain clinical reference significance for determining the diagnosis and prognosis of BPPV on the weak ear and in different semicircular canal involvement.
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Affiliation(s)
- 姝琪 张
- 中山大学附属第三医院耳鼻咽喉头颈外科(广州,510630)Department of Otorhinolaryngology Head and Neck Surgery, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510630, China
| | - 志成 黎
- 中山大学附属第三医院耳鼻咽喉头颈外科(广州,510630)Department of Otorhinolaryngology Head and Neck Surgery, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510630, China
| | - 凌伟 李
- 中山大学附属第三医院耳鼻咽喉头颈外科(广州,510630)Department of Otorhinolaryngology Head and Neck Surgery, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510630, China
| | - 祥丽 曾
- 中山大学附属第三医院耳鼻咽喉头颈外科(广州,510630)Department of Otorhinolaryngology Head and Neck Surgery, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510630, China
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Dissociation between Caloric and Video Head Impulse Tests in Dizziness Clinics. Audiol Res 2022; 12:423-432. [PMID: 36004951 PMCID: PMC9404865 DOI: 10.3390/audiolres12040043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 07/31/2022] [Accepted: 08/05/2022] [Indexed: 11/17/2022] Open
Abstract
Vestibular assessment tests such as the video head impulse test (vHIT) for the horizontal semicircular canal, and caloric test (Cal), both evaluate horizontal canal function. One would assume that the outcomes for these tests should lead to concordant results, yet several studies have suggested that dissociation can occur in certain pathological conditions. As this topic remains inconclusive, this review aims to analyze the scientific evidence regarding the patterns of hypofunction observed in vHIT and Cal in different otoneurological diseases. A comprehensive review of the literature regarding dissociation between these tests in common neurotological diseases was carried out. Articles were analyzed when data for vHIT and Cal were described in a way that it was possible to calculate discordance rates; both retrospective and prospective studies were analyzed. In this review, the discordance rates were as follows: 56% in Ménière’s disease, 51.5% in vestibular migraine, 37.2% in vestibular schwannoma, and 20.8% in vestibular neuritis. These results highlight the benefit of using both Cal and vHIT, and that they are complementary tests.
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Maudoux A, Vitry S, El-Amraoui A. Vestibular Deficits in Deafness: Clinical Presentation, Animal Modeling, and Treatment Solutions. Front Neurol 2022; 13:816534. [PMID: 35444606 PMCID: PMC9013928 DOI: 10.3389/fneur.2022.816534] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/23/2022] [Indexed: 11/13/2022] Open
Abstract
The inner ear is responsible for both hearing and balance. These functions are dependent on the correct functioning of mechanosensitive hair cells, which convert sound- and motion-induced stimuli into electrical signals conveyed to the brain. During evolution of the inner ear, the major changes occurred in the hearing organ, whereas the structure of the vestibular organs remained constant in all vertebrates over the same period. Vestibular deficits are highly prevalent in humans, due to multiple intersecting causes: genetics, environmental factors, ototoxic drugs, infections and aging. Studies of deafness genes associated with balance deficits and their corresponding animal models have shed light on the development and function of these two sensory systems. Bilateral vestibular deficits often impair individual postural control, gaze stabilization, locomotion and spatial orientation. The resulting dizziness, vertigo, and/or falls (frequent in elderly populations) greatly affect patient quality of life. In the absence of treatment, prosthetic devices, such as vestibular implants, providing information about the direction, amplitude and velocity of body movements, are being developed and have given promising results in animal models and humans. Novel methods and techniques have led to major progress in gene therapies targeting the inner ear (gene supplementation and gene editing), 3D inner ear organoids and reprograming protocols for generating hair cell-like cells. These rapid advances in multiscale approaches covering basic research, clinical diagnostics and therapies are fostering interdisciplinary research to develop personalized treatments for vestibular disorders.
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Affiliation(s)
- Audrey Maudoux
- Unit Progressive Sensory Disorders, Pathophysiology and Therapy, Institut Pasteur, Institut de l'Audition, Université de Paris, INSERM-UMRS1120, Paris, France.,Center for Balance Evaluation in Children (EFEE), Otolaryngology Department, Assistance Publique des Hôpitaux de Paris, Robert-Debré University Hospital, Paris, France
| | - Sandrine Vitry
- Unit Progressive Sensory Disorders, Pathophysiology and Therapy, Institut Pasteur, Institut de l'Audition, Université de Paris, INSERM-UMRS1120, Paris, France
| | - Aziz El-Amraoui
- Unit Progressive Sensory Disorders, Pathophysiology and Therapy, Institut Pasteur, Institut de l'Audition, Université de Paris, INSERM-UMRS1120, Paris, France
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McCaslin DL. The Relationship Between Hearing and Balance Function: Toward a Unitary Study of the Auditory and Vestibular Systems. J Am Acad Audiol 2021; 32:477. [PMID: 34965593 DOI: 10.1055/s-0041-1740396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Devin L McCaslin
- Deputy Editor-in-Chief, Journal of the American Academy of Audiology.,Director of Audiology, Michigan Medicine.,Professor, Otolaryngology-Head and Neck Surgery, University of Michigan Medical School
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Curthoys IS. The Neural Basis of Skull Vibration Induced Nystagmus (SVIN). Audiol Res 2021; 11:557-566. [PMID: 34698054 PMCID: PMC8544221 DOI: 10.3390/audiolres11040050] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/09/2021] [Accepted: 10/11/2021] [Indexed: 11/16/2022] Open
Abstract
I list a summary of the major clinical observations of SVIN in patients with total unilateral vestibular loss (TUVL) and show how basic results from neurophysiology can explain these clinical observations. The account integrates results from single neuron recordings of identified semicircular canal and otolith afferent neurons in guinea pigs in response to low frequency skull vibration with evidence of the eye movement response in cats to selective semicircular canal stimulation (both individual and combined) and a simple model of nystagmus generation to show how these results explain most of the major characteristics of SVIN.
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Affiliation(s)
- Ian S Curthoys
- Vestibular Research Laboratory, School of Psychology, The University of Sydney, Sydney, NSW 2006, Australia
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