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Wang X, Zhang Y, Guo T, Wu S, Zhong J, Cheng C, Sui X. Selective intrafascicular stimulation of myelinated and unmyelinated nerve fibers through a longitudinal electrode: A computational study. Comput Biol Med 2024; 176:108556. [PMID: 38733726 DOI: 10.1016/j.compbiomed.2024.108556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 05/05/2024] [Indexed: 05/13/2024]
Abstract
Carbon nanotube (CNT) fiber electrodes have demonstrated exceptional spatial selectivity and sustained reliability in the context of intrafascicular electrical stimulation, as evidenced through rigorous animal experimentation. A significant presence of unmyelinated C fibers, known to induce uncomfortable somatosensory experiences, exists within peripheral nerves. This presence poses a considerable challenge to the excitation of myelinated Aβ fibers, which are crucial for tactile sensation. To achieve nuanced tactile sensory feedback utilizing CNT fiber electrodes, the selective stimulation of Aβ sensory afferents emerges as a critical factor. In confronting this challenge, the present investigation sought to refine and apply a rat sciatic-nerve model leveraging the capabilities of the COMSOL-NEURON framework. This approach enables a systematic evaluation of the influence exerted by stimulation parameters and electrode geometry on the activation dynamics of both myelinated Aβ and unmyelinated C fibers. The findings advocate for the utilization of current pulses featuring a pulse width of 600 μs, alongside the deployment of CNT fibers characterized by a diminutive diameter of 10 μm, with an exclusively exposed cross-sectional area, to facilitate reduced activation current thresholds. Comparative analysis under monopolar and bipolar electrical stimulation conditions revealed proximate activation thresholds, albeit with bipolar stimulation exhibiting superior fiber selectivity relative to its monopolar counterpart. Concerning pulse waveform characteristics, the adoption of an anodic-first biphasic stimulation modality is favored, taking into account the dual criteria of activation threshold and fiber selectivity optimization. Consequently, this investigation furnishes an efficacious stimulation paradigm for the selective activation of touch-related nerve fibers, alongside provisioning a comprehensive theoretical foundation for the realization of natural tactile feedback within the domain of prosthetic hand applications.
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Affiliation(s)
- Xintong Wang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yapeng Zhang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Tianruo Guo
- Graduate School of Biomedical Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Shuhui Wu
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Junwen Zhong
- Department of Electromechanical Engineering, University of Macau, Macau SAR, 999078, China
| | - Chengkung Cheng
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China; Med-X Research Institute, Shanghai Jiao Tong University, Engineering Research Center of Digital Medicine, Ministry of Education, Shanghai, China
| | - Xiaohong Sui
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
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Cicero L, Puleio R, Cassata G, Cirincione R, Camarda L, Caracappa D, D’Itri L, Licciardi M, Vigni GE. Peripheral Nerve Regeneration at 1 Year: Biodegradable Polybutylene Succinate Artificial Scaffold vs. Conventional Epineurial Sutures. Polymers (Basel) 2023; 15:3398. [PMID: 37631456 PMCID: PMC10458963 DOI: 10.3390/polym15163398] [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: 07/19/2023] [Revised: 08/02/2023] [Accepted: 08/11/2023] [Indexed: 08/27/2023] Open
Abstract
The utilization of a planar poly(1,4-butylene succinate) (PBS) scaffold has been demonstrated as an effective approach for preserving nerve continuity and facilitating nerve regeneration. In this study, we assessed the characteristics of a microfibrous tubular scaffold specifically designed and fabricated through electrospinning, utilizing PBS as a biocompatible and biodegradable material. These scaffolds were evaluated as nerve guide conduits in a rat model of sciatic nerve neurotmesis, demonstrating both their biodegradability and efficacy in enhancing the reconstruction process over a long-term period (1-year follow-up). Histological assay and electrophysiological evaluation were performed to compare the long-term outcomes following sutureless repair with the microfibrillar wrap to outcomes obtained using traditional suture repair.
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Affiliation(s)
- Luca Cicero
- Centro Mediterraneo Ricerca e Training (Ce.Me.Ri.T), Istituto Zooprofilattico Sperimentale della Sicilia “A. Mirri”, 90129 Palermo, Italy; (L.C.); (G.C.); (R.C.)
| | - Roberto Puleio
- Laboratorio Istopatologia e Immunoistochimica, Dipartimento Ricerca Biotecnologica e Diagnostica Specialistica, Istituto Zooprofilattico Sperimentale della Sicilia “A. Mirri”, 90129 Palermo, Italy;
| | - Giovanni Cassata
- Centro Mediterraneo Ricerca e Training (Ce.Me.Ri.T), Istituto Zooprofilattico Sperimentale della Sicilia “A. Mirri”, 90129 Palermo, Italy; (L.C.); (G.C.); (R.C.)
| | - Roberta Cirincione
- Centro Mediterraneo Ricerca e Training (Ce.Me.Ri.T), Istituto Zooprofilattico Sperimentale della Sicilia “A. Mirri”, 90129 Palermo, Italy; (L.C.); (G.C.); (R.C.)
| | - Lawrence Camarda
- Department of Orthopaedics and Traumatology, University of Palermo, 90133 Palermo, Italy; (L.C.); (L.D.); (G.E.V.)
| | - Dario Caracappa
- Dipartimento di Discipline Chirurgiche, Oncologiche e Stomatologiche (DICHIRONS), Università degli Studi di Palermo, 90127 Palermo, Italy;
| | - Lorenzo D’Itri
- Department of Orthopaedics and Traumatology, University of Palermo, 90133 Palermo, Italy; (L.C.); (L.D.); (G.E.V.)
| | - Mariano Licciardi
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF), Università degli Studi di Palermo, 90132 Palermo, Italy
| | - Giulio Edoardo Vigni
- Department of Orthopaedics and Traumatology, University of Palermo, 90133 Palermo, Italy; (L.C.); (L.D.); (G.E.V.)
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Throckmorton GA, Thayer W, Duco Jansen E, Mahadevan-Jansen A. Infrared neural stimulation markedly enhances nerve functionality assessment during nerve monitoring. Sci Rep 2023; 13:4362. [PMID: 36928795 PMCID: PMC10020565 DOI: 10.1038/s41598-023-31384-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 03/10/2023] [Indexed: 03/18/2023] Open
Abstract
In surgical procedures where the risk of accidental nerve damage is prevalent, surgeons commonly use electrical stimulation (ES) during intraoperative nerve monitoring (IONM) to assess a nerve's functional integrity. ES, however, is subject to off-target stimulation and stimulation artifacts disguising the true functionality of the specific target and complicating interpretation. Lacking a stimulation artifact and having a higher degree of spatial specificity, infrared neural stimulation (INS) has the potential to improve upon clinical ES for IONM. Here, we present a direct comparison between clinical ES and INS for IONM performance in an in vivo rat model. The sensitivity of INS surpasses that of ES in detecting partial forms of damage while maintaining a comparable specificity and sensitivity to more complete forms. Without loss in performance, INS is readily compatible with existing clinical nerve monitoring systems. These findings underscore the clinical potential of INS to improve IONM and surgical outcomes.
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Affiliation(s)
- Graham A Throckmorton
- Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Station B, Box 351631, Nashville, TN, 37235-1631, USA
- Vanderbilt Biophotonics Center, 410 24th Ave. South, Nashville, TN, 37232, USA
| | - Wesley Thayer
- Department of Plastic Surgery, Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN, 37232, USA
| | - E Duco Jansen
- Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Station B, Box 351631, Nashville, TN, 37235-1631, USA
- Vanderbilt Biophotonics Center, 410 24th Ave. South, Nashville, TN, 37232, USA
- Department of Neurological Surgery, Vanderbilt University Medical Center, 1161 21St Avenue, Nashville, TN, 37232-2380, USA
| | - Anita Mahadevan-Jansen
- Department of Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, Station B, Box 351631, Nashville, TN, 37235-1631, USA.
- Vanderbilt Biophotonics Center, 410 24th Ave. South, Nashville, TN, 37232, USA.
- Department of Neurological Surgery, Vanderbilt University Medical Center, 1161 21St Avenue, Nashville, TN, 37232-2380, USA.
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN, 37232, USA.
- Department of Surgery, Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN, 37232, USA.
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Chan SY, Kuo CW, Liao TT, Peng CW, Hsieh TH, Chang MY. Time-course gait pattern analysis in a rat model of foot drop induced by ventral root avulsion injury. Front Hum Neurosci 2022; 16:972316. [PMID: 36601128 PMCID: PMC9806139 DOI: 10.3389/fnhum.2022.972316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 11/24/2022] [Indexed: 12/23/2022] Open
Abstract
Foot drop is a common clinical gait impairment characterized by the inability to raise the foot or toes during walking due to the weakness of the dorsiflexors of the foot. Lumbar spine disorders are common neurogenic causes of foot drop. The accurate prognosis and treatment protocols of foot drop are not well delineated in the scientific literature due to the heterogeneity of the underlying lumbar spine disorders, different severities, and distinct definitions of the disease. For translational purposes, the use of animal disease models could be the best way to investigate the pathogenesis of foot drop and help develop effective therapeutic strategies for foot drops. However, no relevant and reproducible foot drop animal models with a suitable gait analysis method were developed for the observation of foot drop symptoms. Therefore, the present study aimed to develop a ventral root avulsion (VRA)-induced foot drop rat model and record detailed time-course changes of gait pattern following L5, L6, or L5 + L6 VRA surgery. Our results suggested that L5 + L6 VRA rats exhibited changes in gait patterns, as compared to sham lesion rats, including a significant reduction of walking speed, step length, toe spread, and swing phase time, as well as an increased duration of the stance phase time. The ankle kinematic data exhibited that the ankle joint angle increased during the mid-swing stage, indicating a significant foot drop pattern during locomotion. Time-course observations displayed that these gait impairments occurred as early as the first-day post-lesion and gradually recovered 7-14 days post-injury. We conclude that the proposed foot drop rat model with a video-based gait analysis approach can precisely detect the foot drop pattern induced by VRA in rats, which can provide insight into the compensatory changes and recovery in gait patterns and might be useful for serving as a translational platform bridging human and animal studies for developing novel therapeutic strategies for foot drop.
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Affiliation(s)
- Shu-Yen Chan
- Department of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan,Graduate Institute of Medical Science, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chi-Wei Kuo
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, Chang Gung University, Taoyuan, Taiwan
| | - Tsai-Tsen Liao
- Graduate Institute of Medical Science, College of Medicine, Taipei Medical University, Taipei, Taiwan,Cell Physiology and Molecular Image Research Center, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Chih-Wei Peng
- School of Biomedical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei, Taiwan,International Ph.D. Program in Biomedical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei, Taiwan
| | - Tsung-Hsun Hsieh
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, Chang Gung University, Taoyuan, Taiwan,Neuroscience Research Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan,Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan,*Correspondence: Ming-Yuan Chang Tsung-Hsun Hsieh
| | - Ming-Yuan Chang
- Division of Neurosurgery, Department of Surgery, Min-Sheng General Hospital, Taoyuan, Taiwan,Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan,Discipline of Marketing, College of Management, Yuan Ze University, Taoyuan, Taiwan,*Correspondence: Ming-Yuan Chang Tsung-Hsun Hsieh
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Stochastic spinal neuromodulation tunes the intrinsic logic of spinal neural networks. Exp Neurol 2022; 355:114138. [DOI: 10.1016/j.expneurol.2022.114138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 05/30/2022] [Accepted: 06/01/2022] [Indexed: 11/22/2022]
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Cicero L, Licciardi M, Cirincione R, Puleio R, Giammona G, Giglia G, Sardo P, Edoardo Vigni G, Cioffi A, Sanfilippo A, Cassata G. Polybutylene succinate artificial scaffold for peripheral nerve regeneration. J Biomed Mater Res B Appl Biomater 2021; 110:125-134. [PMID: 34180135 PMCID: PMC9290626 DOI: 10.1002/jbm.b.34896] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 06/03/2021] [Accepted: 06/13/2021] [Indexed: 12/15/2022]
Abstract
Regeneration and recovery of nerve tissues are a great challenge for medicine, and positively affect the quality of life of patients. The development of tissue engineering offers a new approach to the problem with the creation of multifunctional artificial scaffolds that act on various levels in the damaged tissue, providing physical and biochemical support for the growth of nerve cells. In this study, the effects of the use of a tubular scaffold made of polybutylene succinate (PBS), surgically positioned at the level of a sciatic nerve injured in rat, between the proximal stump and the distal one, was investigated. Scaffolds characterization was carried out by scanning electron microscopy and X‐ray microcomputed tomography and magnetic resonance imaging, in vivo. The demonstration of the nerve regeneration was based on the evaluation of electroneurography, measuring the weight of gastrocnemius and tibialis anterior muscles, histological examination of regenerated nerves and observing the recovery of the locomotor activity of animals. The PBS tubular scaffold minimized iatrogenic trauma on the nerve, acting as a directional guide for the regenerating fibers by conveying them toward the distal stump. In this context, neurotrophic and neurotropic factors may accumulate and perform their functions, while invasion by macrophages and scar tissue is hampered.
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Affiliation(s)
- Luca Cicero
- Centro Mediterraneo Ricerca e Training (Ce.Me.Ri.T)Istituto Zooprofilattico Sperimentale della Sicilia “A. Mirri”PalermoItaly
| | - Mariano Licciardi
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF)Università degli Studi di PalermoPalermoItaly
| | - Roberta Cirincione
- Centro Mediterraneo Ricerca e Training (Ce.Me.Ri.T)Istituto Zooprofilattico Sperimentale della Sicilia “A. Mirri”PalermoItaly
| | - Roberto Puleio
- Centro Mediterraneo Ricerca e Training (Ce.Me.Ri.T)Istituto Zooprofilattico Sperimentale della Sicilia “A. Mirri”PalermoItaly
| | - Gaetano Giammona
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF)Università degli Studi di PalermoPalermoItaly
| | - Giuseppe Giglia
- Dipartimento di BiomedicinaNeuroscienze e Diagnostica Avanzata (BiND) Università degli Studi di PalermoPalermoItaly
| | - Pierangelo Sardo
- Dipartimento di BiomedicinaNeuroscienze e Diagnostica Avanzata (BiND) Università degli Studi di PalermoPalermoItaly
| | - Giulio Edoardo Vigni
- Dipartimento di Discipline Chirurgiche, Oncologiche e StomatologicheUniversità degli Studi di PalermoPalermoItaly
| | - Alessio Cioffi
- Dipartimento di Discipline Chirurgiche, Oncologiche e StomatologicheUniversità degli Studi di PalermoPalermoItaly
| | - Antonino Sanfilippo
- Dipartimento di Discipline Chirurgiche, Oncologiche e StomatologicheUniversità degli Studi di PalermoPalermoItaly
| | - Giovanni Cassata
- Centro Mediterraneo Ricerca e Training (Ce.Me.Ri.T)Istituto Zooprofilattico Sperimentale della Sicilia “A. Mirri”PalermoItaly
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Tuncer S, Akkoca A, Celen MC, Dalkilic N. Can MitoTEMPO protect rat sciatic nerve against ischemia-reperfusion injury? NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2021; 394:545-553. [PMID: 33415504 DOI: 10.1007/s00210-020-02039-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 12/08/2020] [Indexed: 10/22/2022]
Abstract
Abdominal ischemia-reperfusion (I/R) is known to cause both structural and functional damage to sciatic nerve which is related to the oxidative stress. We investigated the protective effects of mitochondria-targeted antioxidant (2-(2,2,6,6-tetramethylpiperidin-1-oxyl-4-ylamino)-2-oxoethyl) triphenylphosphonium chloride (MitoTEMPO) on ischemia-reperfusion-induced nerve damage by using the conduction velocity distribution (CVD) calculations from in vitro compound nerve action potential (CNAP) recordings from rat sciatic nerve. Adult male Wistar albino rats were divided into three groups. The IR and IR + MT groups had aortic cross-clamping for 1 h followed by 2 h reperfusion, while SHAM group had the same procedure without cross-clamping. IR + MT group received 0.7 mg/kg/day MitoTEMPO injection for 28 days before I/R, while other groups received vehicle alone. Ischemia-reperfusion resulted in a significant decrease (p < .05) in maximum depolarizations (mV), areas (mV.ms), and maximum and minimum upstroke velocities (mV/ms) of CNAPs, while injection of MitoTEMPO showed a complete protective effect on these impairments. The histograms for CVD showed that I/R blocked the contribution of fast-conducting fibers (> 60 m/s). MitoTEMPO prevented that blockage and caused a shift in the CVD. Functional nerve damage caused by I/R can be prevented by MitoTEMPO, which can enter mitochondria, the main source of reactive oxygen species (ROS).
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Affiliation(s)
- Seckin Tuncer
- Department of Biophysics, Faculty of Medicine, Eskisehir Osmangazi University, Eskisehir, Turkey.
| | - Ahmet Akkoca
- Department of Occupational Health and Safety, Selcuk University, Taskent Vocational School, Konya, Turkey
| | - Murat Cenk Celen
- Department of Biophysics, Meram Medical Faculty, Necmettin Erbakan University, Konya, Turkey
| | - Nizamettin Dalkilic
- Department of Biophysics, Faculty of Medicine, Baskent University, Ankara, Turkey
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Eslami Gharaati M, Nahavandi A, Baluchnejad Mojarad T, Roghani M. Diabetic Encephalopathy Affecting Mitochondria and Axonal Transport Proteins. Basic Clin Neurosci 2020; 11:781-793. [PMID: 33850615 PMCID: PMC8019849 DOI: 10.32598/bcn.11.6.1657.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 01/10/2019] [Accepted: 05/13/2019] [Indexed: 01/21/2023] Open
Abstract
Introduction Diabetic encephalopathy is described as any cognitive and memory impairments associated with hippocampal degenerative changes, including the neurodegenerative process and decreased number of living cells. Mitochondrial diabetes (MD) appears following activation of mutant mitochondrial DNA and is a combination of diabetes and cognitive deficit. In this research, we showed the correlation of diabetic encephalopathy, dysfunctional mitochondria, and changes in the expression of axonal transport proteins (KIF5b, Dynein). Methods Twenty-four male Wistar rats were divided into three groups: (n=8 in each group):1. Control + saline; 2. Diabetic, and 3. Diabetic + insulin. Before starting the experiments, the animals with blood sugar lower than 150 mg/dL entered the study. Diabetes induction was carried out by Intraperitoneal (IP) Streptozotocin (STZ) administration. Fasting Blood Sugar (FBS) and body weight was checked after the first week and at the end of the eighth week. Then, behavioral studies (elevated plus maze, Y-maze, and passive avoidance learning) were performed. After behavioral studies, blood samples were taken to measure serum insulin level and HgbA1c. Next, fresh hippocampal tissue was collected. Gene expression of motor proteins was assessed by real-time PCR and mitochondrial membrane potential by rhodamine123. Results Our results showed the impairment of HgbA1c, serum insulin, FBS, and weight in the diabetic group (P<0.05). Behavioral tests revealed different degrees of impairment in diabetic rats (P<0.05). KIF5b mRNA expression increased in the hippocampus (P<0.05) with no change in dynein gene expression. These changes were associated with abnormal mitochondrial membrane potential (P<0.05). Conclusion KIF5b mRNA up-regulation in hippocampal neurons of STZ-diabetic rats is a factor that can be involved in abnormal axonal transport and decreased MMP, leading to impairment of mitochondrial function. These manifestations showed mitochondrial dysfunction in diabetes and resulted in abnormal behavioral tests and diabetic encephalopathy.
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Affiliation(s)
- Maryam Eslami Gharaati
- Department of Physiology, School of Medicine, Iran University of Medical Science, Tehran, Iran
| | - Arezo Nahavandi
- Department of Physiology, School of Medicine, Iran University of Medical Science, Tehran, Iran.,Neuroscience Research Center, Iran University of Medical Science, Tehran, Iran
| | | | - Mehrdad Roghani
- Departmentof Physiology, Neurophysiology Research Center, Shahed University, Tehran, Iran
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9
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Tutorial: a computational framework for the design and optimization of peripheral neural interfaces. Nat Protoc 2020; 15:3129-3153. [DOI: 10.1038/s41596-020-0377-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 06/15/2020] [Indexed: 01/05/2023]
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10
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Isaacs J, Patel G, Mallu S, Ugwu-Oju O, Desai A, Borschel G, David D, Protzuk O, Shah S, Semus R. Effect of Reverse End-to-Side (Supercharging) Neurotization in Long Processed Acellular Nerve Allograft in a Rat Model. J Hand Surg Am 2019; 44:419.e1-419.e10. [PMID: 30172450 DOI: 10.1016/j.jhsa.2018.07.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 05/06/2018] [Accepted: 07/11/2018] [Indexed: 02/02/2023]
Abstract
PURPOSE Processed acellular nerve allograft (PNA) has been suggested as a convenient tool for overcoming short and medium nerve defects. Although the clinical implications are unclear, animal data suggest that PNA becomes less effective at longer lengths. Although reverse or supercharging end-to-side nerve transfer may improve the neurotrophic potential in chronically denervated nerve tissue, the application of this strategy to long acellular nerve allograft has not been previously investigated. We hypothesized that supercharging acellular nerve allograft would increase its effective length. METHODS Sprague-Dawley and Thy1-green fluorescent protein Sprague-Dawley rats underwent transection of the tibial nerve, followed by immediate repair with 20-, 40-, or 60-mm acellular nerve allografts processed identically to commercially available human acellular nerve allograft (AxoGen, Inc., Alachua, FL) or isograft. Half of the allograft group was supercharged with a reverse end-to-side transfer from the ipsilateral peroneal nerve. At 10 weeks, the reconstructed nerve in the Thy1-green fluorescent rat groups were exposed and examined under a fluorescence-enabled microscope. At 20 weeks, the remaining rats underwent motor testing and tissue harvest for morphological examination. RESULTS In comparison with a nonenhanced allograft, supercharging had a statistically significant positive impact on the reinnervated muscle normalized force generation and distal axon counts for all graft sizes. Muscles in the supercharged group were heavier than those in the allograft group for the 40-mm-length grafts and G-ratio measurements were higher in the supercharged allograft group for 60-mm-length grafts only. CONCLUSIONS This study supports that hypothesis that supercharging nerve transfer improves axon regeneration within PNA. CLINICAL RELEVANCE When an appropriate donor nerve is available, supercharging nerve transfer may improve nerve regeneration in PNA across long nerve defects.
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Affiliation(s)
- Jonathan Isaacs
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, Richmond, VA.
| | - Gaurangkumar Patel
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, Richmond, VA
| | - Satya Mallu
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, Richmond, VA
| | - Obinna Ugwu-Oju
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, Richmond, VA
| | - Anish Desai
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, Richmond, VA
| | - Gregory Borschel
- Division of Plastic Reconstructive Surgery, Department of Surgery, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Dylan David
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, Richmond, VA
| | - Omar Protzuk
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, Richmond, VA
| | - Shalin Shah
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, Richmond, VA
| | - Rachel Semus
- Division of Hand Surgery, Department of Orthopaedic Surgery, Virginia Commonwealth University Medical Center, Richmond, VA
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Žužek MC, Rozman J, Pečlin P, Vrecl M, Frangež R. Analysis of compound action potentials elicited with specific current stimulating pulses in an isolated rat sciatic nerve. ACTA ACUST UNITED AC 2017; 62:37-48. [DOI: 10.1515/bmt-2015-0167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 01/26/2016] [Indexed: 11/15/2022]
Abstract
AbstractThe ability to selectively stimulate Aα, Aβ-fibers and Aδ-fibers in an isolated rat sciatic nerve (SNR) was assessed. The stimulus used was a current, biphasic pulse with a quasitrapezoidal cathodic phase and rectangular anodic phase where parameters were systematically varied: intensity of the cathodic phase (i
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12
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Christensen MB, Tresco PA. Differences Exist in the Left and Right Sciatic Nerves of Naïve Rats and Cats. Anat Rec (Hoboken) 2015; 298:1492-501. [PMID: 25857635 DOI: 10.1002/ar.23161] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 02/02/2015] [Accepted: 02/09/2015] [Indexed: 12/14/2022]
Abstract
The sciatic nerve of rats and cats is commonly used in experimental models of peripheral nerve injury and repair, as well as experiments involving peripheral nerve electrode implantation. In such experiments, morphometric parameters from the implanted nerve are commonly evaluated and compared to control values obtained from the contralateral nerves. However, this may not be an appropriate approach as differences may naturally exist in the structure of the two nerves owing to developmental or behavioral asymmetry. Additionally, in the cat, baseline values for standard morphometric parameters are not well established. In this study, we characterized fascicle area, fiber count, fiber density, fiber packing, mean g-ratio, and fiber diameter distributions in the rat and cat, as well as investigated the potential for naturally occurring sided differences in these parameters in both species. We also investigated whether animal age or location along the nerve influenced these parameters. We found that sided or left/right leg differences exist in some parameters in both the rat and the cat, calling into question the validity of using the contralateral nerve as a control. We also found that animal age and location along the nerve can make significant differences in the parameters tested, establishing the importance of using control nerves from age- and behaviorally matched animals whose morphometric parameters are collected and compared from the same location.
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Affiliation(s)
- Michael B Christensen
- Department of Bioengineering, College of Engineering, University of Utah, Salt Lake City, Utah
| | - Patrick A Tresco
- Department of Bioengineering, College of Engineering, University of Utah, Salt Lake City, Utah
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Su X, Nickles A, Nelson DE. Differentiation and interaction of tibial versus spinal nerve stimulation for micturition control in the rat. Neurourol Urodyn 2013; 34:92-7. [PMID: 24151044 PMCID: PMC4282097 DOI: 10.1002/nau.22506] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 09/04/2013] [Indexed: 11/06/2022]
Abstract
AIMS To determine time course of the bladder inhibitory response to unilateral or bilateral stimulation of the tibial nerve (TN) and spinal nerve (SN) as well as the interaction of stimulation at these two sites. METHODS In anesthetized female rats, a wire electrode was placed under either one or both of the TN or L6 SN. A cannula was placed into the bladder via the urethra. Saline infusion induced bladder rhythmic contraction (BRC). RESULTS Compared to SN neuromodulation, TN neuromodulation is less efficacious. The first 5-min stimulation at three times motor threshold on the SN and TN decreased the BRC frequency to 9% and 69% of controls, respectively. In contrast to SN stimulation, bilateral TN neuromodulation is not more effective than unilateral and sustained TN stimulation results in an apparent desensitization of the bladder response. If a 15-min TN stimulation was applied, BRCs were shutdown only during the first 5 min of stimulation. If a 5-min stimulation, using sufficient current to abolish BRC, is repeated, at least 20 min between stimulations was required in order for the responses to the first and second stimulations to be equivalent. Finally, stimulation of the TN combined with SN never produced a significantly greater effect than TN or SN stimulation alone. CONCLUSIONS Based on the current experiments, it would appear that SN neuromodulation of bladder activity is preferable to TN stimulation and there is no evidence to suggest that stimulation at both sites would offer a therapeutic advantage over spinal stimulation alone.
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Affiliation(s)
- Xin Su
- Medtronic, Inc., Neuromodulation Research, Minneapolis, Minnesota
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14
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CAPPAERT NATALIELM, RAMEKERS DYAN, MARTENS HUBERTCF, WADMAN WYTSEJ. EFFICACY OF A NEW CHARGE-BALANCED BIPHASIC ELECTRICAL STIMULUS IN THE ISOLATED SCIATIC NERVE AND THE HIPPOCAMPAL SLICE. Int J Neural Syst 2012; 23:1250031. [DOI: 10.1142/s0129065712500311] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Most deep brain stimulators apply rectangular monophasic voltage pulses. By modifying the stimulus shape, it is possible to optimize stimulus efficacy and find the best compromise between clinical effect, minimal side effects and power consumption of the stimulus generator. In this study, we compared the efficacy of three types of charge-balanced biphasic pulses (CBBPs, nominal duration 100 μs) in isolated sciatic nerves and in in vitro hippocampal brain slices of the rat. Using these two models, we tested the efficacy of several stimulus shapes exclusively on axons (in the sciatic nerve) and compared the effect with that of stimuli in the more complex neuronal network of the hippocampal slice by considering the stimulus-response relation. We showed that (i) adding an interphase gap (IPG, range 100–500 μs) to the CBBP enhances stimulus efficacy in the rat sciatic nerve and (ii) that this type of stimuli (CBBP with IPG) is also more effective in hippocampal slices. This benefit was similar for both models of voltage and current stimulation. In our two models, asymmetric CBBPs were less beneficial. Therefore, CBBPs with IPG appear to be well suited for application to DBS, since they enhance efficacy, extend battery life and potentially reduce harmful side effects.
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Affiliation(s)
- NATALIE L. M. CAPPAERT
- Swammerdam Institute for Life Sciences — Center for NeuroScience, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - DYAN RAMEKERS
- Swammerdam Institute for Life Sciences — Center for NeuroScience, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - HUBERT C. F. MARTENS
- Philips Research, Eindhoven, The Netherlands
- Sapiens Steering Brain Stimulation B.V., High Tech Campus 48, 5656 AE, Eindhoven, The Netherlands
| | - WYTSE J. WADMAN
- Swammerdam Institute for Life Sciences — Center for NeuroScience, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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15
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Su () X, Nickles A, Nelson DE. Comparison of neural targets for neuromodulation of bladder micturition reflex in the rat. Am J Physiol Renal Physiol 2012; 303:F1196-206. [DOI: 10.1152/ajprenal.00343.2012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Spinal nerve (SN) stimulation inhibits the bladder rhythmic contraction (BRC) in anesthetized rats. This preparation was used to study the effects of electrical stimulation of the tibial nerve (TN) and the dorsal nerve of the clitoris (DNC) on BRC. Stimulation of the TN and DNC for 10 min produced a frequency- and intensity-dependent attenuation of the frequency of bladder contractions. As observed with the SN, 10-Hz stimulation of either TN or DNC produced the greatest degree of inhibition, with lower or higher frequencies being either less efficacious or inactive. In contrast to the prolonged inhibition produced by SN stimulation, both TN and DNC stimulation produced “short” lasting inhibition of bladder contractions and the maximal inhibition occurred during stimulation. TN stimulation was effective over only a narrow range of current intensities [3–4 × motor threshold current for inducing a toe twitch ( Tmot)] and only at a frequency of 10 Hz. Stimulation of TN at 10 Hz, 3 × Tmot inhibited BRC to 23% of control. Ten-hertz DNC stimulation at 2 × TEAS, the threshold current for evoking a reflex anal sphincter contraction, decreased the frequency of contractions to 4% of control. Although compared with the respective threshold current the BRC response was more sensitive to DNC compared with TN stimulation, the absolute current required to reduce BRC using DNC stimulation appeared to be higher. Comparing the effects of TN and DNC stimulation to our previous results with SN stimulation, SN stimulation produces the largest duration and efficacy of bladder inhibition.
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Affiliation(s)
- Xin Su ()
- Neuromodulation Research, Medtronic, Incorporated, Minneapolis, Minnesota; and
| | - Angela Nickles
- Physiology Research Laboratory, Medtronic, Incorporated, Minneapolis, Minnesota
| | - Dwight E. Nelson
- Neuromodulation Research, Medtronic, Incorporated, Minneapolis, Minnesota; and
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16
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Severo Do Nascimento P, Lovatel GA, Ilha J, Schaan BD, Achaval M. Diabetes increases mechanical sensitivity and causes morphological abnormalities in the sural nerve that are prevented by treadmill training. Muscle Nerve 2012; 47:46-52. [DOI: 10.1002/mus.23450] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2012] [Indexed: 01/28/2023]
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17
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Raspopovic S, Capogrosso M, Badia J, Navarro X, Micera S. Experimental Validation of a Hybrid Computational Model for Selective Stimulation Using Transverse Intrafascicular Multichannel Electrodes. IEEE Trans Neural Syst Rehabil Eng 2012; 20:395-404. [DOI: 10.1109/tnsre.2012.2189021] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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18
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Raspopovic S, Capogrosso M, Micera S. A Computational Model for the Stimulation of Rat Sciatic Nerve Using a Transverse Intrafascicular Multichannel Electrode. IEEE Trans Neural Syst Rehabil Eng 2011; 19:333-44. [DOI: 10.1109/tnsre.2011.2151878] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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19
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Haastert-Talini K, Schaper-Rinkel J, Schmitte R, Bastian R, Mühlenhoff M, Schwarzer D, Draeger G, Su Y, Scheper T, Gerardy-Schahn R, Grothe C. In Vivo Evaluation of Polysialic Acid as Part of Tissue-Engineered Nerve Transplants. Tissue Eng Part A 2010; 16:3085-98. [DOI: 10.1089/ten.tea.2010.0180] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Kirsten Haastert-Talini
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
- Center for Systems Neurosciences (ZSN), Hannover, Germany
| | - Janett Schaper-Rinkel
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
- Center for Systems Neurosciences (ZSN), Hannover, Germany
| | - Ruth Schmitte
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
| | - Rode Bastian
- Institute of Technical Chemistry, University of Hannover, Hannover, Germany
| | - Martina Mühlenhoff
- Institute for Cellular Chemistry, Hannover Medical School, Hannover, Germany
| | - David Schwarzer
- Institute for Cellular Chemistry, Hannover Medical School, Hannover, Germany
| | - Gerald Draeger
- Institute of Organic Chemistry, University of Hannover, Hannover, Germany
| | - Yi Su
- Institute of Organic Chemistry, University of Hannover, Hannover, Germany
| | - Thomas Scheper
- Institute of Technical Chemistry, University of Hannover, Hannover, Germany
| | - Rita Gerardy-Schahn
- Center for Systems Neurosciences (ZSN), Hannover, Germany
- Institute for Cellular Chemistry, Hannover Medical School, Hannover, Germany
| | - Claudia Grothe
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
- Center for Systems Neurosciences (ZSN), Hannover, Germany
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20
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Badia J, Pascual-Font A, Vivó M, Udina E, Navarro X. Topographical distribution of motor fascicles in the sciatic-tibial nerve of the rat. Muscle Nerve 2010; 42:192-201. [PMID: 20544926 DOI: 10.1002/mus.21652] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Knowledge of the intraneural topography of peripheral nerves may help to improve nerve repair after injuries and the selectivity of neural interfaces. We studied the fascicular pattern of motor fibers of the rat sciatic-tibial nerve. We carried out an anatomical dissection of the muscular tributaries of the tibial nerve in the leg. Immunohistochemistry against choline acetyltransferase was used to identify motor axons. Retrograde tracing allowed localization of the muscular fascicles at proximal levels of the sciatic trunk. The distribution of motor fibers in transverse section of the tibial nerve is not homogeneous; two clusters were identified, each one containing fibers of functionally related muscles. Retrograde tracing allowed for the identification of motor fascicles, each one well localized along the sciatic nerve. In the rat there is a somatotopic organization of the sciatic nerve, with muscular fascicles maintaining the same relative position along the entire nerve.
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Affiliation(s)
- Jordi Badia
- Neuroplasticity and Regeneration Group, Institute of Neurosciences, Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra E-08193, Spain
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21
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Kuhn A, Keller T, Lawrence M, Morari M. The Influence of Electrode Size on Selectivity and Comfort in Transcutaneous Electrical Stimulation of the Forearm. IEEE Trans Neural Syst Rehabil Eng 2010; 18:255-62. [PMID: 20071267 DOI: 10.1109/tnsre.2009.2039807] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Andreas Kuhn
- Automatic Control Laboratory, ETH Zurich, 8092 Zurich, Switzerland
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22
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Ackermann DM, Foldes EL, Bhadra N, Kilgore KL. Effect of bipolar cuff electrode design on block thresholds in high-frequency electrical neural conduction block. IEEE Trans Neural Syst Rehabil Eng 2009; 17:469-77. [PMID: 19840914 DOI: 10.1109/tnsre.2009.2034069] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Many medical conditions are characterized by undesired or pathological peripheral neurological activity. The local delivery of high-frequency alternating currents (HFAC) has been shown to be a fast acting and quickly reversible method of blocking neural conduction and may provide a treatment alternative for eliminating pathological neural activity in these conditions. This work represents the first formal study of electrode design for high-frequency nerve block, and demonstrates that the interpolar separation distance for a bipolar electrode influences the current amplitudes required to achieve conduction block in both computer simulations and mammalian whole nerve experiments. The minimal current required to achieve block is also dependent on the diameter of the fibers being blocked and the electrode-fiber distance. Single fiber simulations suggest that minimizing the block threshold can be achieved by maximizing both the bipolar activating function (by adjusting the bipolar electrode contact separation distance) and a synergistic addition of membrane sodium currents generated by each of the two bipolar electrode contacts. For a rat sciatic nerve, 1.0-2.0 mm represented the optimal interpolar distance for minimizing current delivery.
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Affiliation(s)
- D Michael Ackermann
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44109, USA.
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23
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Kuhn A, Keller T, Micera S, Morari M. Array electrode design for transcutaneous electrical stimulation: A simulation study. Med Eng Phys 2009; 31:945-51. [PMID: 19540788 DOI: 10.1016/j.medengphy.2009.05.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2008] [Revised: 04/29/2009] [Accepted: 05/01/2009] [Indexed: 11/29/2022]
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Raimondo S, Fornaro M, Di Scipio F, Ronchi G, Giacobini-Robecchi MG, Geuna S. Chapter 5: Methods and protocols in peripheral nerve regeneration experimental research: part II-morphological techniques. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2009; 87:81-103. [PMID: 19682634 DOI: 10.1016/s0074-7742(09)87005-0] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
This paper critically overviews the main procedures used for carrying out morphological analysis of peripheral nerve fibers in light, confocal, and electron microscopy. In particular, this paper emphasizes the importance of osmium tetroxide post-fixation as a useful procedure to be adopted independently from the embedding medium. In order to facilitate the use of any described techniques, all protocols are presented in full details. The pros and cons for each method are critically addressed and practical indications on the different imaging approaches are reported. Moreover, the basic rules of morpho-quantitative stereological analysis of nerve fibers are described addressing the important concepts of design-based sampling and the disector. Finally, a comparison of stereological analysis on myelinated nerve fibers between paraffin- and resin-embedded rat radial nerves is reported showing that different embedding procedures might influence the distribution of size parameters.
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Affiliation(s)
- Stefania Raimondo
- Department of Clinical and Biological Sciences, San Luigi Gonzaga School of Medicine, University of Turin, Turin 10043, Italy
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25
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Kuhn A, Keller T, Lawrence M, Morari M. A model for transcutaneous current stimulation: simulations and experiments. Med Biol Eng Comput 2008; 47:279-89. [PMID: 19005714 DOI: 10.1007/s11517-008-0422-z] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2008] [Accepted: 10/01/2008] [Indexed: 11/28/2022]
Abstract
Complex nerve models have been developed for describing the generation of action potentials in humans. Such nerve models have primarily been used to model implantable electrical stimulation systems, where the stimulation electrodes are close to the nerve (near-field). To address if these nerve models can also be used to model transcutaneous electrical stimulation (TES) (far-field), we have developed a TES model that comprises a volume conductor and different previously published non-linear nerve models. The volume conductor models the resistive and capacitive properties of electrodes, electrode-skin interface, skin, fat, muscle, and bone. The non-linear nerve models were used to conclude from the potential field within the volume conductor on nerve activation. A comparison of simulated and experimentally measured chronaxie values (a measure for the excitability of nerves) and muscle twitch forces on human volunteers allowed us to conclude that some of the published nerve models can be used in TES models. The presented TES model provides a first step to more extensive model implementations for TES in which e.g., multi-array electrode configurations can be tested.
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Affiliation(s)
- Andreas Kuhn
- Automatic Control Laboratory, ETH Zurich, Physikstrasse 3, 8092 Zurich, Switzerland.
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26
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Prodanov D, Feirabend HKP. Automated characterization of nerve fibers labeled fluorescently: determination of size, class and spatial distribution. Brain Res 2008; 1233:35-50. [PMID: 18703026 DOI: 10.1016/j.brainres.2008.07.049] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2007] [Revised: 07/04/2008] [Accepted: 07/07/2008] [Indexed: 10/21/2022]
Abstract
Morphological classification of nerve fibers could help interpret the assessment of neural regeneration and the understanding of selectivity of nerve stimulation. Specific populations of myelinated nerve fibers can be investigated by retrograde tracing from a muscle followed by microscopic measurements of the labeled fibers at different anatomical levels. Gastrocnemius muscles of adult rats were injected with the retrograde tracer Fluoro-Gold. After a survival period of 3 days, cross-sections of spinal cords, ventral roots, sciatic, and tibial nerves were collected and imaged on a fluorescence microscope. Nerve fibers were classified using a variation-based criterion acting on the distribution of their equivalent diameters. The same criterion was used to classify the labeled axons using the size of the fluorescent marker. Measurements of the axons were paired to those of the entire fibers (axons+myelin sheaths) in order to establish the correspondence between so-established axonal and fiber classifications. It was found that nerve fibers in L6 ventral roots could be classified into four populations comprising two classes of Aalpha (denoted Aalpha1 and Aalpha2), Agamma, and an additional class of Agammaalpha fibers. Cut-off borders between Agamma and Agammaalpha fiber classes were estimated to be 5.00+/-0.09 microm (SEM); between Agammaalpha and Aalpha1 fiber classes to be 6.86+/-0.11 microm (SEM); and between Aalpha1 and Aalpha2 fiber classes to be 8.66+/-0.16 microm (SEM). Topographical maps of the nerve fibers that innervate the gastrocnemius muscles were constructed per fiber class for the spinal root L6. The major advantage of the presented approach consists of the combined indirect classification of nerve fiber types and the construction of topographical maps of so-identified fiber classes.
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Affiliation(s)
- Dimiter Prodanov
- Department of Physiology and Pharmacology, Catholic University of Louvain, Brussels, Belgium.
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