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Yuan F, Ding DL, Wang J, Cao YT, Salvi RJ, Qi WD. [Inner hair cells loss by carboplatin and the changes of cochlear compound action potential in chinchillas]. Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2020; 55:506-513. [PMID: 32842367 DOI: 10.3760/cma.j.cn.115330-20200426-00332] [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] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To measure the cochlear compound action potential (CAP) and the densities of hair cells (HCs) along the whole length of the basilar membrane (BM) in adult chinchillas. And to investigate the relationship between the severity of inner hair cells (IHCs) loss and the changes of CAP by using carboplatin-cochlear lesion model. Methods: Totally 18 chinchillas were recruited after ontological evaluation. They were randomly divided into three groups (with 6 subjects in each), A: control, B and C: legion groups treated with one or two shot(s) of carboplatin respectively (76 mg/kg in one shot, i.p., one-week interval between the two shots). Endpoint tests were performed 30 days after the carboplatin treatment in groups B and C, and matched time in group A. A sliver-ball electrode was placed into round window niche via hypotympanic approach in anesthetized chinchilla. CAP was measured in response to clicks and tone burst of 0.5, 1, 2, 4, 8, 16 kHz respectively under anesthesia. CAP amplitudes and thresholds were measured and compared across the groups. After the recording, the whole cochlea surface preparation was made and the HCs were stained in histochemistry against substrate of succinate dehydrogenase (SDH). Images were taken with high-resolution digital camera under light microscope and across the whole cochlea. The length of the basilar membrane (BM) and the number of both IHCs and OHCs were counted. The HC density was calculated as the number of HCs per 10% BM length. Results: The CAP thresholds were (7.1±2.6), (25.4±5.0), (24.6±5.4), (10.4±5.0), (0.4±1.4), (4.2±6.3) and (17.1±14.1) dB SPL (from 6 subjects in group A, n=12 ears) corresponding to stimuli of Click and 0.5, 1, 2, 4, 8, 16 kHz tone bursts respectively. The total number of cochlear HCs were measured as (8 936±643) (x±s) and the average length of the BMs was (17.73±1.012) mm from the six subjects in the group A (n=12 ears). The HC density was found to be varied slightly across the BM. There was no significant CAP threshold difference between the control (group A) and the group B, which received one shot of carboplatin. However, the maximal CAP amplitude was reduced by 40% in the group B and compared with group A. Correspondingly, approximately 40% loss of IHCs were seen. In contrast, a significant CAP threshold shift was seen in subjects receiving two shots of carboplatin (group C), which was accompanied by a loss of 90% IHCs. Conclusions: The CAP thresholds of adult chinchillas show typical open-V shape with the lowest values at 2, 4, and 8 kHz. IHC loss by carboplatin in certain degree is well correlated with CAP amplitude reduction, but does not change the threshold when inner hair cell loss reaches 40%, however, if inner hair cell loss exceeds 80%, the threshold shift of CAP will be inevitable.
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Affiliation(s)
- F Yuan
- Department of Otorhinolaryngology Head and Neck surgery, Huashan Hospital of Fudan University, Shanghai 200040, China
| | - D L Ding
- Center for Hearing and Deafness, Department of Communicative Disorders and Sciences, State University of New York at Buffalo. Buffalo, NY 14214, USA; Department of Otorhinolaryngology Head and Neck Surgery, Affiliated Sixth People's Hospital of Shanghai Jiaotong University, Shanghai 200233, China
| | - J Wang
- Department of Otorhinolaryngology Head and Neck Surgery, Affiliated Sixth People's Hospital of Shanghai Jiaotong University, Shanghai 200233, China; School of Human Communication Disorders, Dalhousie University, Halifax, NS 250101, Canada
| | - Y T Cao
- Department of Otorhinolaryngology Head and Neck surgery, Huashan Hospital of Fudan University, Shanghai 200040, China
| | - R J Salvi
- Center for Hearing and Deafness, Department of Communicative Disorders and Sciences, State University of New York at Buffalo. Buffalo, NY 14214, USA
| | - W D Qi
- Department of Otorhinolaryngology Head and Neck surgery, Huashan Hospital of Fudan University, Shanghai 200040, China
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Levy TJ, Ahmed U, Tsaava T, Chang YC, Lorraine PJ, Tomaio JN, Cracchiolo M, Lopez M, Rieth L, Tracey KJ, Zanos S, Zanos TP. An impedance matching algorithm for common-mode interference removal in vagus nerve recordings. J Neurosci Methods 2019; 330:108467. [PMID: 31654663 DOI: 10.1016/j.jneumeth.2019.108467] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 09/06/2019] [Accepted: 10/17/2019] [Indexed: 01/02/2023]
Abstract
BACKGROUND The peripheral nervous system is involved in a multitude of physiological functions. Recording neural signals provides information that can be used by diagnostic bioelectronic medicine devices, closed-loop neuromodulation therapies and other neuroprosthetic applications. The ability to accurately record these signals is challenging, due to the presence of various biological and instrument-related interference sources. NEW METHOD We developed a common-mode interference rejection algorithm based on an impedance matching approach for bipolar cuff electrodes. Two unipolar channels were recorded from the two electrode contacts of a bipolar cuff. The impedance mismatch was estimated and used to correct one of the two channels. RESULTS When applied to electrocardiographic (ECG) artifacts collected from three mice using CorTec electrodes, the algorithm reduced the interference to noise ratio (INR) over simple subtraction by 12 dB on average. The algorithm also reduced the INR of stimulation artifacts in recordings from three rats collected using flexible electrodes by an additional 2.4 dB. In the same experiments evoked electromyographic (EMG) interference was suppressed by 1.3 dB. COMPARISON WITH EXISTING METHODS Simple subtraction is the common approach for reducing common-mode interference in bipolar recordings, however impedance mismatches that exist or emerge compromise its efficiency. CONCLUSIONS The algorithm significantly reduced the common-mode interference from ECG artifacts, stimulation artifacts, and evoked EMG interference, while retaining neural signals, in two animal models and two recording setups. This approach can be used in a variety of different neurophysiological setups to remove common-mode interference from a variety of sources.
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Affiliation(s)
- Todd J Levy
- Institute of Bioelectronic Medicine, Feinstein Institute for Medical Research, Manhasset, NY, 11030, USA.
| | - Umair Ahmed
- Institute of Bioelectronic Medicine, Feinstein Institute for Medical Research, Manhasset, NY, 11030, USA
| | - Tea Tsaava
- Institute of Bioelectronic Medicine, Feinstein Institute for Medical Research, Manhasset, NY, 11030, USA
| | - Yao-Chuan Chang
- Institute of Bioelectronic Medicine, Feinstein Institute for Medical Research, Manhasset, NY, 11030, USA
| | | | - Jacquelyn N Tomaio
- Institute of Bioelectronic Medicine, Feinstein Institute for Medical Research, Manhasset, NY, 11030, USA
| | - Marina Cracchiolo
- Institute of Bioelectronic Medicine, Feinstein Institute for Medical Research, Manhasset, NY, 11030, USA; The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, PI, 56127, Italy
| | - Maria Lopez
- Institute of Bioelectronic Medicine, Feinstein Institute for Medical Research, Manhasset, NY, 11030, USA
| | - Loren Rieth
- Institute of Bioelectronic Medicine, Feinstein Institute for Medical Research, Manhasset, NY, 11030, USA
| | - Kevin J Tracey
- Institute of Bioelectronic Medicine, Feinstein Institute for Medical Research, Manhasset, NY, 11030, USA
| | - Stavros Zanos
- Institute of Bioelectronic Medicine, Feinstein Institute for Medical Research, Manhasset, NY, 11030, USA
| | - Theodoros P Zanos
- Institute of Bioelectronic Medicine, Feinstein Institute for Medical Research, Manhasset, NY, 11030, USA; Zucker School of Medicine at Hofstra/Northwell, Heampstead, NY, 11549, USA.
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Wang D, Xiong B, Xiong F, Chen GD, Hu BH, Sun W. Apical hair cell degeneration causes the increase in the amplitude of summating potential. Acta Otolaryngol 2016; 136:1255-1260. [PMID: 27424625 DOI: 10.1080/00016489.2016.1203989] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
CONCLUSION This study indicates that the lesion of hair cells in the apical turn of the cochlea can cause the change in the summating potential (SP)/Compound potential (CAP) ratio. OBJECTIVES Electrocochleography is a valuable clinic test for diagnosis of cochlear pathologies and the ratio of SP to CAP has been used to identify Meniere's disease. However, it remains controversial whether the increase of the SP/CAP ratio represents exclusively the endolymphatic hydrops. METHOD This study measured the SP and CAP in mice that displayed outer hair cell (OHC) degeneration in the apical section of the cochlea as their age increased. RESULTS As compared with the mice aged 8-10 months, the 24-month old mice displayed a significant increase in the amplitude of SP at 12-16 kHz. This result suggests that the degeneration of OHCs in the apical turn leads to the increase of the + SP at the middle frequencies. In contrast, the aging mice did not have a significant change in the CAP amplitude at super-threshold levels.
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Kaufmann D, West PJ, Smith MD, Yagen B, Bialer M, Devor M, White HS, Brennan KC. sec-Butylpropylacetamide (SPD), a new amide derivative of valproic acid for the treatment of neuropathic and inflammatory pain. Pharmacol Res 2017; 117:129-39. [PMID: 27890817 DOI: 10.1016/j.phrs.2016.11.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 10/20/2016] [Accepted: 11/22/2016] [Indexed: 01/12/2023]
Abstract
Chronic pain is a multifactorial disease comprised of both inflammatory and neuropathic components that affect ∼20% of the world's population. sec-Butylpropylacetamide (SPD) is a novel amide analogue of valproic acid (VPA) previously shown to possess a broad spectrum of anticonvulsant activity. In this study, we defined the pharmacokinetic parameters of SPD in rat and mouse, and then evaluated its antinociceptive potential in neuropathic and acute inflammatory pain models. In the sciatic nerve ligation (SNL) model of neuropathic pain, SPD was equipotent to gabapentin and more potent than its parent compound VPA. SPD also showed either higher or equal potency to VPA in the formalin, carrageenan, and writhing tests of inflammatory pain. SPD showed no effects on compound action potential properties in a sciatic nerve preparation, suggesting that its mechanism of action is distinct from local anesthetics and membrane stabilizing drugs. SPD's activity in both neuropathic and inflammatory pain warrants its development as a potential broad-spectrum anti-nociceptive drug.
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Reeves TM, Trimmer PA, Colley BS, Phillips LL. Targeting Kv1.3 channels to reduce white matter pathology after traumatic brain injury. Exp Neurol 2016; 283:188-203. [PMID: 27302680 DOI: 10.1016/j.expneurol.2016.06.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 05/31/2016] [Accepted: 06/10/2016] [Indexed: 02/07/2023]
Abstract
Axonal injury is present in essentially all clinically significant cases of traumatic brain injury (TBI). While no effective treatment has been identified to date, experimental TBI models have shown promising axonal protection using immunosuppressants FK506 and Cyclosporine-A, with treatment benefits attributed to calcineurin inhibition or protection of mitochondrial function. However, growing evidence suggests neuroprotective efficacy of these compounds may also involve direct modulation of ion channels, and in particular Kv1.3. The present study tested whether blockade of Kv1.3 channels, using Clofazimine (CFZ), would alleviate TBI-induced white matter pathology in rodents. Postinjury CFZ administration prevented suppression of compound action potential (CAP) amplitude in the corpus callosum of adult rats following midline fluid percussion TBI, with injury and treatment effects primarily expressed in unmyelinated CAPs. Kv1.3 protein levels in callosal tissue extracts were significantly reduced postinjury, but this loss was prevented by CFZ treatment. In parallel, CFZ also attenuated the injury-induced elevation in pro-inflammatory cytokine IL1-β. The effects of CFZ on glial function were further studied using mixed microglia/astrocyte cell cultures derived from P3-5 mouse corpus callosum. Cultures of callosal glia challenged with lipopolysaccharide exhibited a dramatic increase in IL1-β levels, accompanied by reactive morphological changes in microglia, both of which were attenuated by CFZ treatment. These results support a cell specific role for Kv1.3 signaling in white matter pathology after TBI, and suggest a treatment approach based on the blockade of these channels. This therapeutic strategy may be especially efficacious for normalizing neuro-glial interactions affecting unmyelinated axons after TBI.
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Affiliation(s)
- Thomas M Reeves
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University Medical Center, Richmond, VA 23298, United States
| | - Patricia A Trimmer
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University Medical Center, Richmond, VA 23298, United States
| | - Beverly S Colley
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University Medical Center, Richmond, VA 23298, United States
| | - Linda L Phillips
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University Medical Center, Richmond, VA 23298, United States
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