Intervertebral disk degeneration results in alterations in the mechanical, chemical, and electrical properties of the disk tissue. The purpose of this study is to record spatially resolved streaming potential measurements across intervertebral disks exposed to cyclic compressive loading. We hypothesize that the streaming potential profile across the disk will vary with radial position and frequency and is proportional to applied load amplitude, according to the presumed fluid-solid relative velocity and measured glycosaminoglycan content. Needle electrodes were fabricated using a linear array of AgAgCl micro-electrodes and inserted into human motion segments in the midline from anterior to posterior. They were connected to an amplifier to measure electrode potentials relative to the saline bath ground. Motion segments were loaded in axial compression under a preload of 500 N, sinusoidal amplitudes of +/-200 N and +/-400 N, and frequencies of 0.01 Hz, 0.1 Hz, and 1 Hz. Streaming potential data were normalized by applied force amplitude, and also compared with paired experimental measurements of glycosaminoglycans in each disk. Normalized streaming potentials varied significantly with sagittal position and there was a significant location difference at the different frequencies. Normalized streaming potential was largest in the central nucleus region at frequencies of 0.1 Hz and 1.0 Hz with values of approximately 3.5 microVN. Under 0.01 Hz loading, normalized streaming potential was largest in the outer annulus regions with a maximum value of 3.0 microVN. Correlations between streaming potential and glycosaminoglycan content were significant, with R(2) ranging from 0.5 to 0.8. Phasic relationships between applied force and electrical potential did not differ significantly by disk region or frequency, although the largest phase angles were observed at the outermost electrodes. Normalized streaming potentials were associated with glycosaminoglycan content, fluid, and ion transport. Results suggested that at higher frequencies the transport of water and ions in the central nucleus region may be larger, while at lower frequencies there is enhanced transport near the periphery of the annulus. This study provides data that will be helpful to validate multiphasic models of the disk.
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http://dx.doi.org/10.1115/1.3005164 | DOI Listing |
Digit Health
December 2024
School of Nursing, University of Northern British Columbia, Prince George, BC, Canada.
Background: During the COVID-19 pandemic, governments across the world implemented processes and policies to limit the spread of COVID-19, especially in long-term care (LTC) homes. This led to changes in technology use for persons living in LTC homes, their families and friends, as well as the paid workforce dedicated to caring for them.
Objective: The study describes the role of technology and its impact on the experiences of LTC staff working in northern and rural areas in Western Canada during COVID-19.
Gait initiation is a fundamental human task, requiring one or more anticipatory postural adjustments (APA) prior to stepping. Deviations in amplitude and timing of APAs exist in Parkinson's disease (PD), causing dysfunctional postural control which increases the risk of falls. The motor cortex and basal ganglia have been implicated in the regulation of postural control, however, their dynamics during gait initiation, relationship to APA metrics, and response to pharmacotherapy such as levodopa are unknown.
View Article and Find Full Text PDFNeurol Genet
February 2025
Department of Neurology and.
Objectives: To report a case of adult-onset non-dystrophic myotonia complicated by recurrent episodes of laryngospasm.
Methods: The patient is a 35-year-old man who was admitted to our hospital for recurrent episodes of apnea requiring endotracheal intubation with mechanical ventilation. He underwent extensive evaluation, including EMG, laryngoscopy, muscle biopsy, and genetic testing, which revealed a diagnosis of non-dystrophic myotonia.
Fluids Barriers CNS
December 2024
School of Mechanical Engineering, Purdue University, 585 Purdue Mall, West Lafayette, 47907, IN, USA.
The importance of optimizing intrathecal drug delivery is highlighted by its potential to improve patient health outcomes. Findings from previous computational studies, based on an individual or a small group, may not be applicable to the wider population due to substantial geometric variability. Our study aims to circumvent this problem by evaluating an individual's cycle-averaged Lagrangian velocity field based on the geometry of their spinal subarachnoid space.
View Article and Find Full Text PDFNeuromodulation
December 2024
Institute of Science and Technology for Brain-inspired Intelligence, Fudan University, Shanghai, China; Ministry of Education Frontiers Center for Brain Science, Fudan University, Shanghai, China; Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; Academy for Engineering and Technology, Fudan University, Shanghai, China. Electronic address:
Objective: This study aims to facilitate the translation of innovative closed-loop deep brain stimulation (DBS) strategies from theory to practice by establishing a research platform. The platform addresses the challenges of real-time stimulation artifact removal, low-latency feedback stimulation, and rapid translation from animal to clinical experiments.
Materials And Methods: The platform comprises hardware for neural sensing and stimulation, a closed-loop software framework for real-time data streaming and computation, and an algorithm library for implementing closed-loop DBS strategies.
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