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Physiological Reports Jan 2020Neuromodulation based on the vagal anti-inflammatory reflex has emerged as an exciting therapeutic approach for chronic inflammatory diseases. However, it is unclear...
Neuromodulation based on the vagal anti-inflammatory reflex has emerged as an exciting therapeutic approach for chronic inflammatory diseases. However, it is unclear whether direct stimulation of the vagus or of pelvic nerves coming from sacral roots, providing the bulk of colonic parasympathetic innervation, is the best approach. We hypothesized that sacral nerve stimulation (SNS) would be an effective treatment for colitis. Age and sex-matched Sprague-Dawley rats were administered 5% dextran sulphate sodium (DSS) in drinking water ad libitum for 7 days. A group of rats was sacrificed after DSS treatment, and the remaining rats were randomized to either sham-SNS or SNS groups, which were performed for 1 hr daily for 10 days. Stimulations were delivered via chronically implanted electrodes using an 8-channel universal pulse generator. Sacral nerve stimulation promoted recovery of colitis demonstrated by decreased disease activity index, myeloperoxidase activity, tissue TNF-alpha, and histological scores as well as an increased colonic M2 macrophage population. Heart rate variability analysis demonstrated a decrease in low frequency and increase in high frequency with SNS, corresponding to increased vagal tone. Additionally, plasma pancreatic peptide was increased and norepinephrine was decreased after SNS in colitis while colon tissue acetylcholine was increased with SNS. This is the first study to the best of our knowledge that demonstrates the benefit of SNS with autonomic mediation. SNS alters the expression of inflammatory cytokines and macrophages as well as modulates neurotransmitters involved in systemic inflammation.
Topics: Animals; Colitis; Colon; Dextran Sulfate; Disease Models, Animal; Electric Stimulation Therapy; Heart Rate; Lumbosacral Plexus; Macrophages; Neuroimmunomodulation; Parasympathetic Nervous System; Peroxidase; Random Allocation; Rats; Rats, Sprague-Dawley; Spinal Nerves; Tumor Necrosis Factor-alpha
PubMed: 31925899
DOI: 10.14814/phy2.14294 -
BMC Musculoskeletal Disorders Jul 2013Clinical examination of patients with chronic lumbar radiculopathy aims to clarify whether there is nerve root impingement. The aims of this study were to investigate...
BACKGROUND
Clinical examination of patients with chronic lumbar radiculopathy aims to clarify whether there is nerve root impingement. The aims of this study were to investigate the association between findings at clinical examination and nerve root impingement, to evaluate the accuracy of clinical index tests in a specialised care setting, and to see whether imaging clarifies the cause of chronic radicular pain.
METHODS
A total of 116 patients referred with symptoms of lumbar radiculopathy lasting more than 12 weeks and at least one positive index test were included. The tests were the straight leg raising test, and tests for motor muscle strength, dermatome sensory loss, and reflex impairment. Magnetic resonance imaging (n = 109) or computer tomography (n = 7) were imaging reference standards. Images were analysed at the level of single nerve root(s), and nerve root impingement was classified as present or absent. Sensitivities, specificities, and positive and negative likelihood ratios (LR) for detection of nerve root impingement were calculated for each individual index test. An overall clinical evaluation, concluding on the level and side of the radiculopathy, was performed.
RESULTS
The prevalence of disc herniation was 77.8%. The diagnostic accuracy of individual index tests was low with no tests reaching positive LR >4.0 or negative LR <0.4. The overall clinical evaluation was slightly more accurate, with a positive LR of 6.28 (95% CI 1.06-37.21) for L4, 1.74 (95% CI 1.04-2.93) for L5, and 1.29 (95% CI 0.97-1.72) for S1 nerve root impingement. An overall clinical evaluation, concluding on the level and side of the radiculopathy was also performed, and receiver operating characteristic (ROC) analysis with area under the curve (AUC) calculation for diagnostic accuracy of this evaluation was performed.
CONCLUSIONS
The accuracy of individual clinical index tests used to predict imaging findings of nerve root impingement in patients with chronic lumbar radiculopathy is low when applied in specialised care, but clinicians' overall evaluation improves diagnostic accuracy slightly. The tests are not very helpful in clarifying the cause of radicular pain, and are therefore inaccurate for guidance in the diagnostic workup of the patients. The study population was highly selected and therefore the results from this study should not be generalised to unselected patient populations in primary care nor to even more selected surgical populations.
Topics: Adult; Chronic Disease; Exercise Test; Female; Humans; Low Back Pain; Lumbar Vertebrae; Magnetic Resonance Imaging; Male; Middle Aged; Nerve Compression Syndromes; Physical Examination; Radiculopathy; Reproducibility of Results; Spinal Nerve Roots; Tomography, X-Ray Computed; Young Adult
PubMed: 23837886
DOI: 10.1186/1471-2474-14-206 -
Annals of Medicine and Surgery (2012) Jan 2022Mobile Schwannoma is a rare soft tissue tumor that commonly involves the elderly population. It has no cellular material and grows as solitary, firm, oval, encapsulated...
INTRODUCTION
Mobile Schwannoma is a rare soft tissue tumor that commonly involves the elderly population. It has no cellular material and grows as solitary, firm, oval, encapsulated benign tumors from the sensory (dorsal) nerve root. If multiple, they are usually associated with Neurofibromatosis type 2 (NF-2). The initial sign and symptoms include segmental pain and paresthesia. It may lead to myelopathy if the tumor expands.
CASE PRESENTATION
We present a twenty-year-old female with chronic lower backache radiating to the ipsilateral thigh with no urinary or fecal incontinence. On physical examination, the ankle reflex was hypoactive on the left side, and the straight leg raise test was positive. A large 32 × 15 × 14 mm heterogeneous enhancing focal lesion was found on the posterior side of L5 and S1 vertebrae with severe central canal stenosis. A diagnosis of nerve sheath tumor was made based on contrast MRI pre-operatively. The underlying cause was a nerve sheath tumor. A total bilateral laminectomy at the L1-S5 level and mass excision was performed, preserving nerve roots. The postoperative period was uneventful, and no tumor re-growth was noticed.
CLINICAL DISCUSSION
Schwannoma is a slow-growing tumor; benign; usually, less than 8 cm in diameter tumor, commonly found in the head and neck region. It is the 3rd most common soft tissue tumor and the 2nd most common intradural extramedullary tumor. In our report, a young, non-Caucasian female patient is diagnosed with schwannoma, which is quite rare. In our case, a larger tumor of size 32 × 15 × 14 mm was noted, affecting the posterior body of L5 and S1 vertebrae in the left lateral recess with impingement of the left S1 traversing nerve root. Around 29% of spinal root nerve tumors are schwannomas. As the tumor grows slowly, the diagnosis may be delayed.
CONCLUSION
Schwannoma is a slow-growing solitary, firm, oval, encapsulated benign tumor arising from the sensory (dorsal) nerve root. Histopathology plays a vital role in diagnosis, and overall, the disease has a favorable prognosis. Therefore, an appropriate approach is necessary to rule out the disease.
PubMed: 34984098
DOI: 10.1016/j.amsu.2021.102986 -
The Journal of Physiology Nov 19961. Experiments were carried out to test the effect of changes in spindle resting discharge on the size of monosynaptic reflexes in the cat and on the H reflex in humans....
1. Experiments were carried out to test the effect of changes in spindle resting discharge on the size of monosynaptic reflexes in the cat and on the H reflex in humans. Resting discharge was altered by contracting the triceps surae muscle at longer (hold-long) or shorter (hold-short) lengths than that at which the reflex was tested. 2. The reflex in the cat was larger after hold-long than after hold-short conditioning, and the difference, after an initial decline, was well maintained. For the human H reflex a similar pattern was observed except that 15 s after muscle conditioning the difference in reflex size had disappeared. 3. Monosynaptic reflex depression immediately after hold-long conditioning, when most of the muscle spindles are silent, was attributed to the high level of spindle discharge during the immediately preceding hold-long period. The time course of this inhibition was too long to be accounted for by presynaptic inhibition. 4. In the cat heteronymous muscle conditioning was used to test whether presynaptic inhibition could be responsible for reflex depression using the synergist muscle pair lateral gastrocnemius-soleus and medial gastrocnemius. Conditioning one of the pair did not affect the reflex in the other, the opposite result to that expected with presynaptic inhibition. A similar experiment in which the triceps H reflex in human subjects was facilitated by a quadriceps volley gave the same result. 5. Thus this study presents evidence that monosynaptic reflexes are depressed by the on-going discharge of muscle spindles in the homonymous muscle, but that this depression does not appear to involve "classical' presynaptic inhibition.
Topics: Adult; Animals; Cats; Electric Stimulation; Electrophysiology; Evoked Potentials; Female; H-Reflex; Humans; Male; Muscle Contraction; Muscles; Reflex, Monosynaptic; Spinal Nerve Roots
PubMed: 8951729
DOI: 10.1113/jphysiol.1996.sp021767 -
American Journal of Physiology. Heart... May 2005It has been suggested that nitric oxide (NO) is a key modulator of both baroreceptor and exercise pressor reflex afferent signals processed within the nucleus tractus...
It has been suggested that nitric oxide (NO) is a key modulator of both baroreceptor and exercise pressor reflex afferent signals processed within the nucleus tractus solitarius (NTS). However, studies investigating the independent effects of NO within the NTS on the function of each reflex have produced inconsistent results. To address these concerns, the effects of microdialyzing 10 mM L-arginine, an NO precursor, and 20 mM N(G)-nitro-L-arginine methyl ester (L-NAME), an NO synthase inhibitor, into the NTS on baroreceptor and exercise pressor reflex function were examined in 17 anesthetized cats. Arterial baroreflex regulation of heart rate was quantified using vasoactive drugs to induce acute changes in mean arterial pressure (MAP). To activate the exercise pressor reflex, static hindlimb contractions were induced by electrical stimulation of spinal ventral roots. To isolate the exercise pressor reflex, contractions were repeated after barodenervation. The gain coefficient of the arterial cardiac baroreflex was significantly different from control (-0.24 +/- 0.04 beats.min(-1).mmHg(-1)) after the dialysis of L-arginine (-0.18 +/- 0.02 beats.min(-1).mmHg(-1)) and L-NAME (-0.29 +/- 0.02 beats.min(-1).mmHg(-1)). In barodenervated animals, the peak MAP response to activation of the exercise pressor reflex (change in MAP from baseline, 39 +/- 7 mmHg) was significantly attenuated by the dialysis of L-arginine (change in MAP from baseline, 29 +/- 6 mmHg). The results demonstrate that NO within the NTS can independently modulate both the arterial cardiac baroreflex and the exercise pressor reflex. Collectively, these findings provide a neuroanatomical and chemical basis for the regulation of baroreflex and exercise pressor reflex function within the central nervous system.
Topics: Animals; Arginine; Autonomic Nervous System; Baroreflex; Cats; Diffusion; Enzyme Inhibitors; Female; Indazoles; Male; Microdialysis; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Synthase; Physical Exertion; Solitary Nucleus
PubMed: 15604127
DOI: 10.1152/ajpheart.00919.2003 -
The American Psychologist Oct 2018Community-based participatory research (CBPR) answers the call for more patient-centered, community-driven research approaches to address growing health disparities....
Community-based participatory research (CBPR) answers the call for more patient-centered, community-driven research approaches to address growing health disparities. CBPR is a collaborative research approach that equitably involves community members, researchers, and other stakeholders in the research process and recognizes the unique strengths that each bring. The aim of CBPR is to combine knowledge and action to create positive and lasting social change. With its origins in psychology, sociology, and critical pedagogy, CBPR has become a common research approach in the fields of public health, medicine, and nursing. Although it is well aligned with psychology's ethical principles and research aims, it has not been widely implemented in psychology research. The present article introduces CBPR to a general psychology audience while considering the unique aims of and challenges in conducting psychology research. In this article, we define CBPR principles, differentiate it from a more traditional psychology research approach, retrace its historical roots, provide concrete steps for its implementation, discuss its potential benefits, and explore practical and ethical challenges for its integration into psychology research. Finally, we provide a case study of CBPR in psychology to illustrate its key constructs and implementation. In sum, CBPR is a relevant, important, and promising research framework that may guide the implementation of more effective, culturally appropriate, socially just, and sustainable community-based psychology research. (PsycINFO Database Record (c) 2018 APA, all rights reserved).
Topics: Community-Based Participatory Research; Humans; Psychology; Research Design; Social Change
PubMed: 29355352
DOI: 10.1037/amp0000167 -
European Journal of Translational... Jun 2016Spinal cord injuries (SCI) result in the loss of movement and sensory feedback as well as organs dysfunctions. For example, nearly all SCI subjects loose their bladder...
Spinal cord injuries (SCI) result in the loss of movement and sensory feedback as well as organs dysfunctions. For example, nearly all SCI subjects loose their bladder control and are prone to kidney failure if they do not proceed to intermittent (self-) catheterization. Electrical stimulation of the sacral spinal roots with an implantable neuroprosthesis is a promising approach, with commercialized products, to restore continence and control micturition. However, many persons do not ask for this intervention since a surgical deafferentation is needed and the loss of sensory functions and reflexes become serious side effects of this procedure. Recent results renewed interest in spinal cord stimulation. Stimulation of existing pre-cabled neural networks involved in physiological processes regulation is suspected to enable synergic recruitment of spinal fibers. The development of direct spinal stimulation strategies aiming at bladder and bowel functions restoration would therefore appear as a credible alternative to existent solutions. However, a lack of suitable large animal model complicates these kinds of studies. In this article, we propose a new animal model of spinal stimulation -pig- and will briefly introduce results from one first acute experimental validation session.
PubMed: 27478570
DOI: 10.4081/ejtm.2016.6034 -
Heliyon Dec 2020Folkloric or galenic preparations of valerian roots and rhizomes have been used as sedatives/anxiolytics and sleep inducers since ancient times. "Valerianas" are plants...
Folkloric or galenic preparations of valerian roots and rhizomes have been used as sedatives/anxiolytics and sleep inducers since ancient times. "Valerianas" are plants that naturally grow in our region. Although some of them are used in folk medicine, they lack scientific information. We performed a comparative study of the phytochemical composition and the potential effects of ethanolic extracts of argentine valerian species: Sm Phil. and Poepp. ex DC., from "Patagonia Argentina"; (Griseb.) Höck and Griseb., from the central part of our country, and (as the reference plant). All these plants were rich in phenolic compounds, evidenced the presence of ligands for the benzodiazepine binding site of the GABA receptor and were able to induce sedation as assessed by loss-of-righting reflex assays (500 mg/kg, i.p.). Mice treated with , and extracts showed reduced exploratory behaviors while produced anxiolytic-like activities (500 mg/kg, i.p.) in the Hole board test. Oral administrations (300 mg/kg and 600 mg/kg, p.o.) evidenced sedative effects for and anxiolytic-like properties for , and extracts. Our native valerian species are active on the CNS, validating its folkloric use as anxiolytic/sedative and sleep enhancers.
PubMed: 33367125
DOI: 10.1016/j.heliyon.2020.e05691 -
American Journal of Physiology. Heart... Sep 2004It has been suggested that the midbrain periaqueductal gray (PAG) is a neural integrating site for the interaction between the muscle pressor reflex and the arterial...
It has been suggested that the midbrain periaqueductal gray (PAG) is a neural integrating site for the interaction between the muscle pressor reflex and the arterial baroreceptor reflex. The underlying mechanisms are poorly understood. The purpose of this study was to examine the roles of GABA and nitric oxide (NO) in modulating the PAG integration of both reflexes. To activate muscle afferents, static contraction of the triceps surae muscle was evoked by electrical stimulation of the L7 and S1 ventral roots of 18 anesthetized cats. In the first group of experiments (n = 6), the pressor response to muscle contraction was attenuated by bilateral microinjection of muscimol (a GABA receptor agonist) into the lateral PAG [change in mean arterial pressure (DeltaMAP) = 24 +/- 5 vs. 46 +/- 8 mmHg in control]. Conversely, the pressor response was significantly augmented by 0.1 mM bicuculline, a GABAA receptor antagonist (DeltaMAP = 65 +/- 10 mmHg). In addition, the effect of GABAA receptor blockade on the reflex response was significantly blunted after sinoaortic denervation and vagotomy (n = 4). In the second group of experiments (n = 8), the pressor response to contraction was significantly attenuated by microinjection of L-arginine into the lateral PAG (DeltaMAP = 26 +/- 4 mmHg after L-arginine injection vs. 45 +/- 7 mmHg in control). The effect of NO attenuation was antagonized by bicuculline and was reduced after denervation. These data demonstrate that GABA and NO within the PAG modulate the pressor response to muscle contraction and that NO attenuation of the muscle pressor reflex is mediated via arterial baroreflex-engaged GABA increase. The results suggest that the PAG plays an important role in modulating cardiovascular responses when muscle afferents are activated.
Topics: Animals; Arteries; Baroreflex; Bicuculline; Blood Pressure; Cats; Female; GABA Agonists; GABA Antagonists; GABA-A Receptor Antagonists; Male; Mesencephalon; Motor Activity; Muscimol; Muscle Contraction; Muscle, Skeletal; Nitric Oxide; Periaqueductal Gray; Reflex; gamma-Aminobutyric Acid
PubMed: 15087292
DOI: 10.1152/ajpheart.00163.2004 -
The Journal of Physiology Jan 19811. Input from group I afferents of knee flexors and extensors to interneurones in Rexed's laminae V-VI in the cat spinal cord was analysed by use of intracellular...
1. Input from group I afferents of knee flexors and extensors to interneurones in Rexed's laminae V-VI in the cat spinal cord was analysed by use of intracellular recording and electrical stimulation of the nerves to differentiate between group Ia and Ib synaptic actions. The aim was to find out if these interneurones may mediate synaptic actions of both group Ia and Ib afferents. 2. 28% of the forty-nine neurones analysed were excited by both group Ia and group Ib afferents; 32% were inhibited by both and 35% were excited by the one and inhibited by the other. Taking into account all of these actions, input from both subgroups of group I afferents was found in nearly 60% of neurones. Most were also excited and/or inhibited by group I afferents of ankle and toe extensors. 3. Selective (excitatory and/or inhibitory) input from Ia afferents was found in 18% and from Ib afferents in 22% of the neurones. 4. Excitation was evoked from Ia afferents of either knee flexors or extensors but not from both. In several of the neurones Ia i.p.s.p.s were, however, evoked from both posterior biceps-semitendinosus and quadriceps. 5. Intracellular staining with horseradish peroxidase revealed axonal projections of laminae V-VI interneurones to motor nuclei as well as to the intermediate zone, ipsilateral as well as contralateral. No correlation was found between patterns of input from group I afferents and axonal projections, and interneurones co-excited by Ia and Ib afferents were among these with different axonal projections.
Topics: Afferent Pathways; Animals; Axons; Cats; Evoked Potentials; Hindlimb; Horseradish Peroxidase; Interneurons; Muscles; Neurons, Afferent; Reflex; Spinal Nerve Roots; Synapses
PubMed: 7230040
DOI: 10.1113/jphysiol.1981.sp013555