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BMC Infectious Diseases Jan 2024Leprosy is a chronic infectious disease caused by Mycobacterium leprae, predominantly affecting the peripheral nerves, resulting in sensory and motor deficits in the...
BACKGROUND
Leprosy is a chronic infectious disease caused by Mycobacterium leprae, predominantly affecting the peripheral nerves, resulting in sensory and motor deficits in the feet. Foot ulcers and imbalances are frequent manifestations in leprosy, often correlating with diminished sensitivity. While clinical scales and monofilament esthesiometers are conventionally utilized to evaluate foot sensitivity and balance in these patients, their discriminatory power is limited and their effectiveness is greatly dependent on the examiner's proficiency. In contrast, baropodometry and posturography offer a more comprehensive evaluation, aiming to preempt potential damage events. This study aimed was to assess the correlation between baropodometry and force plate measurements in leprosy patients and control participants, to improve the prevention and treatment of foot ulcers and complications associated with leprosy.
METHODOLOGY
This cross-sectional study was conducted during 2022 and enrolled 39 participants (22 patients with multibacillary leprosy and 17 non-leprosy controls). Demographic data were collected, and a monofilament esthesiometer was used to assess sensory deficits. In addition, physical examinations and balance and plantar pressure tests were conducted. The Student's t-test was used to compare mean and maximum plantar pressures between groups. For most COP variables, a Mann-Whitney Wilcoxon test was used, except for AP amplitude which was analyzed with the Student's t-test due to its normal distribution. The relationship between foot pressure and balance control was assessed using Spearman's correlation, focusing on areas with significant pressure differences between groups.
PRINCIPAL FINDINGS
Leprosy patients showed increased pressure in forefoot areas (T1, M1, T2-T5, and M2) and decreased pressure in hindfoot regions (MH and LH) compared to controls. These patients also displayed higher AP and ML amplitudes, suggesting poorer COP control. Correlation analyses between the two groups revealed that foot plantar pressures significantly impact balance control. Specifically, increased T1 region pressures correlated with greater sway in balance tasks, while decreased MH region pressures were linked to reduced COP control.
CONCLUSIONS/SIGNIFICANCE
The findings suggest a joint disturbance of plantar pressure distribution and static balance control in leprosy patients. These alterations may increase the risk of tissue injuries, including calluses and deformities, as well as falls.
Topics: Humans; Cross-Sectional Studies; Diabetic Foot; Leprosy, Multibacillary; Foot; Lower Extremity
PubMed: 38267905
DOI: 10.1186/s12879-023-08749-0 -
Exercise, Sport & Movement 2023The purpose of this study was to determine the following in persons with midportion Achilles tendinopathy (AT): 1) maximal strength and power; 2) neural drive during...
INTRODUCTION/PURPOSE
The purpose of this study was to determine the following in persons with midportion Achilles tendinopathy (AT): 1) maximal strength and power; 2) neural drive during maximal contractions and contractile function during electrically evoked resting contractions; and 3) whether pain, neural drive, and contractile mechanisms contribute to differences in maximal strength.
METHODS
Twenty-eight volunteers (14 AT, 14 controls) completed isometric, concentric, and eccentric maximal voluntary contractions (MVCs) of the plantar flexors in a Biodex dynamometer. Supramaximal electrical stimulation of the tibial nerve was performed to quantify neural drive and contractile properties of the plantar flexors. Pain sensitivity was quantified as the pressure-pain thresholds of the Achilles tendon, medial gastrocnemius, and upper trapezius.
RESULTS
There were no differences in plantar flexion strength or power between AT and controls (isometric MVC: = 0.95; dynamic MVC: = 0.99; power: = 0.98), nor were there differences in neural drive and contractile function ( = 0.55 and = 0.06, respectively). However, the mechanisms predicting maximal strength differed between groups: neural drive predicted maximal strength in controls ( = 0.02) and contractile function predicted maximal strength in AT ( = 0.001). Although pain did not mediate these relationships (i.e., between maximal strength and its contributing mechanisms), pressure-pain thresholds at the upper trapezius were higher in AT ( = 0.02), despite being similar at the calf ( = 0.24) and Achilles tendon ( = 0.40).
CONCLUSIONS
There were no deficits in plantar flexion strength or power in persons with AT, whether evaluated isometrically, concentrically, or eccentrically. However, the mechanisms predicting maximal plantar flexor strength differed between groups, and systemic pain sensitivity was diminished in AT.
PubMed: 38222444
DOI: 10.1249/esm.0000000000000017 -
Nature Nanotechnology Apr 2024One of the critical factors determining the performance of neural interfaces is the electrode material used to establish electrical communication with the neural tissue,...
One of the critical factors determining the performance of neural interfaces is the electrode material used to establish electrical communication with the neural tissue, which needs to meet strict electrical, electrochemical, mechanical, biological and microfabrication compatibility requirements. This work presents a nanoporous graphene-based thin-film technology and its engineering to form flexible neural interfaces. The developed technology allows the fabrication of small microelectrodes (25 µm diameter) while achieving low impedance (∼25 kΩ) and high charge injection (3-5 mC cm). In vivo brain recording performance assessed in rodents reveals high-fidelity recordings (signal-to-noise ratio >10 dB for local field potentials), while stimulation performance assessed with an intrafascicular implant demonstrates low current thresholds (<100 µA) and high selectivity (>0.8) for activating subsets of axons within the rat sciatic nerve innervating tibialis anterior and plantar interosseous muscles. Furthermore, the tissue biocompatibility of the devices was validated by chronic epicortical (12 week) and intraneural (8 week) implantation. This work describes a graphene-based thin-film microelectrode technology and demonstrates its potential for high-precision and high-resolution neural interfacing.
Topics: Rats; Animals; Microelectrodes; Graphite; Nanopores; Prostheses and Implants; Electric Stimulation
PubMed: 38212522
DOI: 10.1038/s41565-023-01570-5 -
Frontiers in Neuroscience 2023It has been shown that estrogen and progesterone receptors are expressed in the spinal cord; therefore, fluctuation in their concentrations may affect the spinal network...
It has been shown that estrogen and progesterone receptors are expressed in the spinal cord; therefore, fluctuation in their concentrations may affect the spinal network and modulate the control of movement. Herein, we assessed the neuro-modulatory effect of sex hormones on the polysynaptic spinal network by using a flexion reflex network as a model system. Twenty-four healthy eumenorrheic women (age 21-37 years) were tested every other day for one menstrual cycle. Serum estradiol and progesterone were acquired at the time of testing. The flexion reflex of the tibialis anterior was elicited by sending an innocuous electrical stimulus directly to the posterior tibial nerve or plantar cutaneous afferent. Analyses were performed for each menstrual cycle phase: the follicular phase and the luteal phase. Increases in estradiol or progesterone concentrations were not associated with reflex duration or root mean squared (RMS) amplitude in either the follicular or luteal phases. In the luteal phase, an increase in the estradiol concentration was associated with a longer latency of the reflex ( = 0.23, = 0.038). The estradiol × progesterone interaction was found towards significance ( = -0.017, = 0.081). These results highlight the potential synergistic effect of estradiol and progesterone and may provide indirect confirmatory evidence of the observed modulatory effect.
PubMed: 38188036
DOI: 10.3389/fnins.2023.1263756 -
ACS Applied Materials & Interfaces Jan 2024RNA interference-based gene therapy has led to a strategy for spinal cord injury (SCI) therapy. However, there have been high requirements regarding the optimal gene...
RNA interference-based gene therapy has led to a strategy for spinal cord injury (SCI) therapy. However, there have been high requirements regarding the optimal gene delivery vector for siRNA-based SCI gene therapy. Here, we developed an injectable and photocurable lipid nanoparticle GelMA (PLNG) hydrogel scaffold for controlled dual siRNA delivery at the SCI wound site. The prepared PLNG scaffold could efficiently protect and retain the bioactivity of the siRNA nanocomplex. It facilitated sustainable siRNA release along with degradation in 7 days. After loading dual siRNA targeting phosphatase and tensin homologue (PTEN) and macrophage migration inhibitory factor (MIF) simultaneously, the locally administered siRNAs/PLNG scaffold efficiently improved the Basso mouse scale (BMS) score and recovered ankle joint movement and plantar stepping after treatment with only three doses. We further proved that the siRNAs/PLNG scaffold successfully regulated the activities of neurons, microglia, and macrophages, thus promoting neuron axon regeneration and remyelination. The protein array results suggested that the siRNAs/PLNG scaffold could increase the expression of growth factors and decrease the expression of inflammatory factors to regulate neuroinflammation in SCI and create a neural repair environment. Our results suggested that the PLNG scaffold siRNA delivery system is a potential candidate for siRNA-based SCI therapy.
Topics: Mice; Animals; Axons; Nerve Regeneration; Spinal Cord Injuries; Neurons; RNA, Small Interfering
PubMed: 38185858
DOI: 10.1021/acsami.3c14902 -
The Journal of Physiology Jan 2024Both ageing and exercise training affect the neuromuscular junction (NMJ) structure. Morphological alterations in the NMJ have been considered to influence neuromuscular...
Both ageing and exercise training affect the neuromuscular junction (NMJ) structure. Morphological alterations in the NMJ have been considered to influence neuromuscular transmission and myofibre properties, but the direct link between the morphology and function has yet to be established. We measured the neuromuscular transmission, myofibre composition and NMJ structure of 5-month-old (young) and 24-month-old untrained (aged control) and trained (aged trained) mice. Aged trained mice were subjected to 2 months of endurance training before the measurement. Neuromuscular transmission was evaluated in vivo as the ratio of ankle plantar flexion torque evoked by the sciatic nerve stimulation to that by direct muscle stimulation. The torque ratio was significantly lower in aged mice than in young and aged trained mice at high-frequency stimulations, showing a significant positive correlation with voluntary grip strength. The degree of pre- to post-synaptic overlap of the NMJ was also significantly lower in aged mice and positively correlated with the torque ratio. We also found that the proportion of fast-twitch fibres in the soleus muscle decreased with age, and that age-related denervation occurred preferentially in fast-twitch fibres. Age-related denervation and a shift in myofibre composition were partially prevented by endurance training. These results suggest that age-related deterioration of the NMJ structure impairs neuromuscular transmission and alters myofibre composition, but these alterations can be prevented by structural amelioration of NMJ with endurance training. Our findings highlight the importance of the NMJ as a major determinant of age-related deterioration of skeletal muscles and the clinical significance of endurance training as a countermeasure. KEY POINTS: The neuromuscular junction (NMJ) plays an essential role in neuromuscular transmission and the maintenance of myofibre properties. We show that neuromuscular transmission is impaired with ageing but recovered by endurance training, which contributes to alterations in voluntary strength. Neuromuscular transmission is associated with the degree of pre- to post-synaptic overlap of the NMJ. Age-related denervation of fast-twitch fibres and a shift in myofibre composition toward a slower phenotype are partially prevented by endurance training. Our study provides substantial evidence that age-related and exercise-induced alterations in neuromuscular transmission and myofibre properties are associated with morphological changes in the NMJ.
PubMed: 38173183
DOI: 10.1113/JP285143 -
International Neurourology Journal Dec 2023Lithotomy position has been widely used in the various urologic surgery. Occasionally sensory and motor problems of the lower extremities are occurred due to the...
PURPOSE
Lithotomy position has been widely used in the various urologic surgery. Occasionally sensory and motor problems of the lower extremities are occurred due to the lithotomy position and these deficits may be related with sciatic nerve injury (SNI). Inflammatory process is a factor to induce functional impairment after SNI. Therefore, we evaluated the role of adenosine A2A receptor agonists, polydeoxyribonucleotide (PDRN) showing anti-inflammatory effect on locomotor function following SNI in rats.
METHODS
Sciatic nerve was compressed with surgical clips for 1 minute after exposing of right sciatic nerve. After 3 days of SNI, PDRN (2, 4, and 8 mg/kg) was applied to the damaged area of sciatic nerve once daily for 10 days. Walking track analysis was conducted for locomotor function and plantar test was performed for thermal pain sensitivity. Level of cyclic adenosine-3´,5´-monophosphate (cAMP) were measured using enzyme-linked immunosorbent assay. Western blot analysis was performed for tumor necrosis factor (TNF)-α, interleukin (IL)-1β, cAMP response element binding protein (CREP), vascular endothelial growth factor (VEGF). Immunofluorescence for neurofilament was also conducted.
RESULTS
Locomotor function was decreased and thermal pain sensitivity was increased by SNI. SNI enhanced proinflammatory cytokines' production, such as TNF-α and IL-1β, while suppressed CREP phosphorylation and cAMP level. SNI also reduced the expression of VEGF and neurofilaments. However, treatment with PDRN inhibited proinflammatory cytokines' production and upregulated CREP phosphorylation and cAMP expression. PDRN also enhanced the expression of VEGF and neurofilaments. As a result, PDRN improved locomotor function and alleviated thermal hyperalgesia after SNI.
CONCLUSION
PDRN has shown potential to be used as an effective treatment for neuropathic pain.
PubMed: 38171324
DOI: 10.5213/inj.2326154.127 -
Journal of the American Podiatric... 2023Diabetes-related peripheral neuropathy (DPN) and limited joint mobility of the foot and ankle are implicated in the development of increased plantar pressures and... (Observational Study)
Observational Study
BACKGROUND
Diabetes-related peripheral neuropathy (DPN) and limited joint mobility of the foot and ankle are implicated in the development of increased plantar pressures and diabetes-related foot ulcers. The extent of this relationship has not been conclusively established. We aimed to determine the relationship between ankle joint and first metatarsophalangeal joint dorsiflexion range of motion and DPN using a cross-sectional observational study design.
METHODS
Primary outcomes were DPN status, ankle joint range of motion (extended and flexed knee lunge tests), and nonweightbearing first metatarsophalangeal joint range of motion. Correlations were performed using Pearson r, and hierarchical regression analyses were undertaken to determine the independent contribution of DPN to the variance in dorsiflexion range of motion of ankle and first metatarsophalangeal joints using standardized β regression coefficients, controlling for age, sex, body mass index, diabetes duration, and hemoglobin A1c level.
RESULTS
One hundred one community-dwelling participants (mean ± SD age, 65.0 ± 11.2 years; 55 men; 97% type 2 diabetes; mean ± SD diabetes duration, 8.7 ± 7.8 years; 23% with DPN) were recruited. Diabetes-related peripheral neuropathy demonstrated significant correlations with reduced range of motion at the ankle joint (knee extended: r = -0.53; P < .001 and knee flexed: r = -0.50; P < .001) and the first metatarsophalangeal joint (r = -0.37; P < .001). Also, DPN made significant, unique contributions to the regression models for range of motion at the ankle joint (knee extended: r2 change = 0.121; β = -0.48; P < .001 and knee flexed: r2 change = 0.109; β = -0.45; P < .001) and first metatarsophalangeal joint (r2 change = 0.037; β = -0.26; P = .048).
CONCLUSIONS
These findings suggest that DPN contributes to reduced ankle and first metatarsophalangeal joint range of motion. Due to the established link between reduced ankle and first metatarsophalangeal joint range of motion and risk of diabetes-related foot ulcer, we recommend that clinicians assess dorsiflexion range of motion at these joints as part of routine foot assessment in people with diabetes, especially those with DPN. Globally, approximately 436 million adults aged 20 to 79 years are living with diabetes.1 Diabetes is the leading cause of lower-limb amputation and is associated with a lifetime incidence of diabetes-related foot ulcer (DFU) of up to 34%.2 Diabetes-related peripheral neuropathy (DPN) affects approximately 30% to 50% of people with diabetes3 and is one of the most significant risk factors for the development of DFU and amputation.4 Diabetes-related peripheral neuropathy occurs as a result of neural ischemia and perineural edema causing neural demyelination, affecting nerve conductivity.5 In the presence of DPN, intrinsic foot muscle wasting can lead to the development of foot deformities such as digital clawing, which, when coupled with structural and functional changes to the skin, make it less resistant to shear forces and further increase plantar pressure and risk of DFU.6,7.
Topics: Male; Adult; Humans; Middle Aged; Aged; Ankle Joint; Ankle; Diabetic Foot; Diabetes Mellitus, Type 2; Cross-Sectional Studies; Diabetic Neuropathies; Metatarsophalangeal Joint; Range of Motion, Articular
PubMed: 38170606
DOI: 10.7547/21-097