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PloS One 2024Orexin-mediated stimulation of orexin receptors 1/2 (OX[1/2]R) may stimulate the diaphragm and genioglossus muscle via activation of inspiratory neurons in the...
Orexin receptor 2 agonist activates diaphragm and genioglossus muscle through stimulating inspiratory neurons in the pre-Bötzinger complex, and phrenic and hypoglossal motoneurons in rodents.
Orexin-mediated stimulation of orexin receptors 1/2 (OX[1/2]R) may stimulate the diaphragm and genioglossus muscle via activation of inspiratory neurons in the pre-Bötzinger complex, which are critical for the generation of inspiratory rhythm, and phrenic and hypoglossal motoneurons. Herein, we assessed the effects of OX2R-selective agonists TAK-925 (danavorexton) and OX-201 on respiratory function. In in vitro electrophysiologic analyses using rat medullary slices, danavorexton and OX-201 showed tendency and significant effect, respectively, in increasing the frequency of inspiratory synaptic currents of inspiratory neurons in the pre-Bötzinger complex. In rat medullary slices, both danavorexton and OX-201 significantly increased the frequency of inspiratory synaptic currents of hypoglossal motoneurons. Danavorexton and OX-201 also showed significant effect and tendency, respectively, in increasing the frequency of burst activity recorded from the cervical (C3-C5) ventral root, which contains axons of phrenic motoneurons, in in vitro electrophysiologic analyses from rat isolated brainstem-spinal cord preparations. Electromyogram recordings revealed that intravenous administration of OX-201 increased burst frequency of the diaphragm and burst amplitude of the genioglossus muscle in isoflurane- and urethane-anesthetized rats, respectively. In whole-body plethysmography analyses, oral administration of OX-201 increased respiratory activity in free-moving mice. Overall, these results suggest that OX2R-selective agonists enhance respiratory function via activation of the diaphragm and genioglossus muscle through stimulation of inspiratory neurons in the pre-Bötzinger complex, and phrenic and hypoglossal motoneurons. OX2R-selective agonists could be promising drugs for various conditions with respiratory dysfunction.
Topics: Animals; Diaphragm; Motor Neurons; Orexin Receptors; Rats; Phrenic Nerve; Mice; Male; Hypoglossal Nerve; Rats, Sprague-Dawley; Inhalation; Medulla Oblongata; Isoquinolines; Pyridines
PubMed: 38917189
DOI: 10.1371/journal.pone.0306099 -
Current Pain and Headache Reports Jun 2024The purpose of this review is to evaluate, discuss and explain the current literature regarding management of post dural puncture headaches (PDPH) during spinal cord... (Review)
Review
PURPOSE OF REVIEW
The purpose of this review is to evaluate, discuss and explain the current literature regarding management of post dural puncture headaches (PDPH) during spinal cord stimulation (SCS) trials.
RECENT FINDINGS
Although an epidural blood patch (EBP) remains the gold standard in treatment of PDPH, current literature describes other modalities including various peripheral nerve blocks and pharmacological treatments to reduce PDPH symptoms. PDPH management in SCS centers around conservative treatment and EBP. It has been shown that some practitioners choose prophylactic measures and/or an EBP at the time of the lead placement. Recent literature regarding obstetric anesthesia related PDPH management has included newer potential modalities for addressing symptom improvement that can also be applied to PDPH from SCS trial dural punctures. Due to limited data overall, further studies are needed to effectively provide a guideline on optimal treatment protocols for PDPH after dural puncture in SCS trials.
PubMed: 38916716
DOI: 10.1007/s11916-024-01289-5 -
International Ophthalmology Jun 2024Papilledema is the optic disc swelling caused by increased intracranial pressure (ICP) that can damage the optic nerve and cause subsequent vision loss.... (Review)
Review
BACKGROUND
Papilledema is the optic disc swelling caused by increased intracranial pressure (ICP) that can damage the optic nerve and cause subsequent vision loss. Pseudopapilledema refers to optic disc elevation without peripapillary fluid that can arise from several optic disc disorders, with optic disc drusen (ODD) being the most frequent cause. Occasionally, pseudopapilledema patients are mistakenly diagnosed as papilledema, leading to the possibility of unneeded procedures. We aim to thoroughly examine the most current evidence on papilledema and pseudopapilledema causes and several methods for distinguishing between both conditions.
METHODS
An extensive literature search was conducted on electronic databases including PubMed and google scholar using keywords that were relevant to the assessed pathologies. Data were collected and then summarized in comprehensive form.
RESULTS
Various techniques are employed to distinguish between papilledema and pseudopapilledema. These techniques include Fundus fluorescein angiography, optical coherence tomography, ultrasonography, and magnetic resonance imaging. Lumbar puncture and other invasive procedures may be needed if results are suspicious.
CONCLUSION
Papilledema is a sight-threatening condition that may lead to visual affection. Many disc conditions may mimic papilledema. Accordingly, differentiation between papilledema and pseudopailledema is crucial and can be conducted through many modalities.
Topics: Papilledema; Humans; Diagnosis, Differential; Tomography, Optical Coherence; Fluorescein Angiography; Optic Disk; Eye Diseases, Hereditary; Optic Nerve Diseases; Fundus Oculi; Magnetic Resonance Imaging; Optic Disk Drusen
PubMed: 38916684
DOI: 10.1007/s10792-024-03215-5 -
International Journal of... Apr 2024Leprosy, caused by the bacterium Mycobacterium leprae, is known to primarily affect the skin and peripheral nerves. We present a rare case of leprosy initially...
Leprosy, caused by the bacterium Mycobacterium leprae, is known to primarily affect the skin and peripheral nerves. We present a rare case of leprosy initially manifesting as demyelinating polyneuropathy. A 46-year-old female presented with progressive weakness, tingling, and numbness in her extremities. Nerve conduction studies revealed evidence of demyelination, prompting further investigations. Skin slit-skin smears confirmed the diagnosis of leprosy, with the presence of acid-fast bacilli. The patient was subsequently started on multidrug therapy, leading to significant clinical improvement. This case highlights the importance of considering leprosy as a differential diagnosis in patients presenting with demyelinating polyneuropathy, especially in endemic regions.
Topics: Humans; Female; Middle Aged; Polyradiculoneuropathy, Chronic Inflammatory Demyelinating; Leprosy; Diagnosis, Differential; Mycobacterium leprae; Skin; Leprostatic Agents
PubMed: 38916395
DOI: 10.4103/ijmy.ijmy_39_24 -
Drug Design, Development and Therapy 2024Nerve injury is a serious complication of percutaneous endoscopic transforaminal lumbar discectomy due to nerve root contact. The maximum tolerable concentration (MTC)...
Determining the Maximum Tolerable Concentration of Ropivacaine to Maintain Sensation of the Nerve Root in Percutaneous Endoscopic Transforaminal Lumbar Discectomy: Can Epidural Anaesthesia Achieve Pain-Tactile Separation Block to Avoid Nerve Injury?
INTRODUCTION
Nerve injury is a serious complication of percutaneous endoscopic transforaminal lumbar discectomy due to nerve root contact. The maximum tolerable concentration (MTC) of ropivacaine concentration for epidural anaesthesia, is defined as the concentration that minimises pain while preserving the sensation of the nerve roots. This distinct advantage allows the patient to provide feedback to the surgeon when the nerve roots are contacted.
METHODS
We used a biased-coin design to determine the MTC, which was estimated by the 10% effective concentration (EC), ie, the concentration at which 10% of patients lost sensation in the nerve roots. The determinant for positive response was lack of sensory feedback upon contact with the nerve root, and the feedback from occurrence of sensations in the innervation area upon contact with the nerve root was defined as a negative response. Primary outcome was the response from contact nerve root. Secondary outcomes were the type and number of statements of negative response and each patient's pain score during surgery.
RESULTS
Fifty-four patients were included in this study. The EC was 0.434% (95% CI: 0.410%, 0.440%) using isotonic regression in comparison with 0.431% (95% CI: 0.399%, 0.444%) using probit regression. Three type statements of negative response were reported including "tactile sensation", radiculalgia, and numbness.
CONCLUSION
The MTC of ropivacaine used for epidural anaesthesia was 0.434% to avoid nerve injury in percutaneous endoscopic transforaminal lumbar discectomy.
Topics: Ropivacaine; Humans; Male; Middle Aged; Female; Lumbar Vertebrae; Adult; Anesthetics, Local; Anesthesia, Epidural; Diskectomy, Percutaneous; Endoscopy; Spinal Nerve Roots; Dose-Response Relationship, Drug; Sensation; Aged
PubMed: 38915867
DOI: 10.2147/DDDT.S451980 -
BioRxiv : the Preprint Server For... Jun 2024Spinal cord stimulation (SCS) has emerged as a therapeutic tool for improving motor function following spinal cord injury. While many studies focus on restoring...
Spinal cord stimulation (SCS) has emerged as a therapeutic tool for improving motor function following spinal cord injury. While many studies focus on restoring locomotion, little attention is paid to enabling standing which is a prerequisite of walking. In this study, we fully characterize a new type of response to SCS, a long extension activated post-stimulation (LEAP). LEAP is primarily directed to ankle extensors and hence has great clinical potential to assist postural movements. To characterize this new response, we used the decerebrate cat model to avoid the suppressive effects of anesthesia, and combined EMG and force measurement in the hindlimb with intracellular recordings in the lumbar spinal cord. Stimulation was delivered as five-second trains via bipolar electrodes placed on the cord surface, and multiple combinations of stimulation locations (L4 to S2), amplitudes (50-600 uA), and frequencies (10-40 Hz) were tested. While the optimum stimulation location and frequency differed slightly among animals, the stimulation amplitude was key for controlling LEAP duration and amplitude. To study the mechanism of LEAP, we performed in vivo intracellular recordings of motoneurons. In 70% of motoneurons, LEAP increased at hyperpolarized membrane potentials indicating a synaptic origin. Furthermore, spinal interneurons exhibited changes in firing during LEAP, confirming the circuit origin of this behavior. Finally, to identify the type of afferents involved in generating LEAP, we used shorter stimulation pulses (more selective for proprioceptive afferents), as well as peripheral stimulation of the sural nerve (cutaneous afferents). The data indicates that LEAP primarily relies on proprioceptive afferents and has major differences from pain or withdrawal reflexes mediated by cutaneous afferents. Our study has thus identified and characterized a novel postural motor response to SCS which has the potential to expand the applications of SCS for patients with motor disorders.
PubMed: 38915687
DOI: 10.1101/2024.06.13.598885 -
BioRxiv : the Preprint Server For... Jun 2024Diabetic peripheral neuropathy (DPN) is a prevalent complication of diabetes mellitus that is caused by metabolic toxicity to peripheral axons. We aimed to gain deep...
Diabetic peripheral neuropathy (DPN) is a prevalent complication of diabetes mellitus that is caused by metabolic toxicity to peripheral axons. We aimed to gain deep mechanistic insight into the disease process using bulk and spatial RNA sequencing on tibial and sural nerves recovered from lower leg amputations in a mostly diabetic population. First, our approach comparing mixed sensory and motor tibial and purely sensory sural nerves shows key pathway differences in affected nerves, with distinct immunological features observed in sural nerves. Second, spatial transcriptomics analysis of sural nerves reveals substantial shifts in endothelial and immune cell types associated with severe axonal loss. We also find clear evidence of neuronal gene transcript changes, like in nerves with axonal loss suggesting perturbed RNA transport into distal sensory axons. This motivated further investigation into neuronal mRNA localization in peripheral nerve axons generating clear evidence of robust localization of mRNAs such as and in human sensory axons. Our work gives new insight into the altered cellular and transcriptomic profiles in human nerves in DPN and highlights the importance of sensory axon mRNA transport as an unappreciated potential contributor to peripheral nerve degeneration.
PubMed: 38915676
DOI: 10.1101/2024.06.15.599167 -
Journal of Korean Neurosurgical Society Jun 2024The Korean Neurosurgical Society, with its 62 years of history, has witnessed substantial growth in the field of neurosurgery, producing over 3,400 neurosurgeons,...
Enhancing the Evaluation System of Training Hospitals for Neurosurgical Residency Training and Education in South Korea : Striving for Balanced Participation and Differentiation.
The Korean Neurosurgical Society, with its 62 years of history, has witnessed substantial growth in the field of neurosurgery, producing over 3,400 neurosurgeons, establishing 12 divisions and 9 regional branches, and advancing in clinical management, diagnostic methods and academic research. Despite these developments, the regulations governing neurosurgical training and evaluation methods for training hospitals have remained largely unchanged, necessitating comprehensive revisions in response to evolving medical environments. To provide balanced participation opportunities for neurosurgery residents, the Korean Neurosurgical Society formed the Training Status Investigation Standard Change Task Force (TF Team) under the Training Education Committee. This paper presents the TF Team's findings and proposals for revising training status investigation standards and evaluation criteria. Through the processes including a lot of team meetings, workshops, education programs, official communications with 12 division societies, benchmarking from other societies and analysis of encrypted data from the past 5 years for neurosurgical training hospitals, the TF Team created a revised training status investigation proposal, supplemented main surgery criteria. And we applied this revised proposal to the training status investigation data collected from training hospitals in 2022 for simulation. We reduced the score for main surgeries to 10 points, introduced core competency surgery standards, allocating 5 points each for brain core competency surgery and spine and peripheral core competency surgery, for a total of 10 points. We also adjusted the major surgery score to 13 points, expanding the total surgery index score to 33 points. We introduced additional definitions for main surgeries in the areas of spine, pediatrics, and functional surgery. The equipment score was reduced from 17 points to 9 points. We specified minimum requirements for resident allocation eligibility, and if a hospital meets all of these criteria, they become eligible to apply for resident allocation. We introduced a new bonus point system for hospitals performing mechanical thrombectomy or stenting and peripheral nerve. The proposed revisions aim to improve the training and education of neurosurgical residents and overall neurosurgical care in Korea by creating a balanced and differentiated evaluation system for training hospitals. Further monitoring, communication, and adjustments are crucial for successful implementation.
PubMed: 38915210
DOI: 10.3340/jkns.2024.0067 -
International Ophthalmology Jun 2024To compare, between Alzheimer's disease (AD) patients and healthy individuals, corneal subbasal nerve plexus (CSNP) parameters and corneal sensitivities.
PURPOSE
To compare, between Alzheimer's disease (AD) patients and healthy individuals, corneal subbasal nerve plexus (CSNP) parameters and corneal sensitivities.
METHODS
Twenty-two patients who were followed up with Alzheimer's disease (Alzheimer's group) and 18 age- and gender-matched healthy individuals (control group) were included in this cross-sectional study. CSNP parameters, including nerve fiber length (NFL), nerve fiber density (NFD), and nerve branch density (NBD), were evaluated using in vivo confocal microscopy. Corneal sensitivity was evaluated using a Cochet-Bonnet esthesiometer. The results were compared between the two groups.
RESULTS
In the Alzheimer's group, NFL was 12.2 (2.4) mm/mm, NFD was 12.5 [3.1] fibers/mm, and NBD was 29.7 [9.37] branches/mm. In the control group, NFL was 16.5 (2.0) mm/mm, NFD was 25.0 [3.13] fibers/mm, and NBD was 37.5 [10.9] branches/mm. All three parameters were significantly lower in the Alzheimer's group compared to the control group (p < 0.001, p < 0.001, and p = 0.001, respectively). Similarly, corneal sensitivity was significantly lower in the Alzheimer's group (55.0 [5.0] mm) compared to the control group (60.0 [5.0] mm) (p < 0.001).
CONCLUSION
We determined that, in AD, corneal sensitivity decreases significantly, in parallel with the decrease in corneal nerves. Changes in the corneal nerve plexus and a decrease in corneal sensitivity may be used in the early diagnosis and follow-up of AD. In addition, ocular surface problems secondary to these changes should also be kept in mind.
Topics: Humans; Female; Male; Cornea; Cross-Sectional Studies; Alzheimer Disease; Aged; Nerve Fibers; Microscopy, Confocal; Middle Aged; Ophthalmic Nerve; Sensation Disorders; Aged, 80 and over
PubMed: 38914919
DOI: 10.1007/s10792-024-03162-1 -
Nature Communications Jun 2024Neuromuscular control of bionic arms has constantly improved over the past years, however, restoration of sensation remains elusive. Previous approaches to reestablish...
Neuromuscular control of bionic arms has constantly improved over the past years, however, restoration of sensation remains elusive. Previous approaches to reestablish sensory feedback include tactile, electrical, and peripheral nerve stimulation, however, they cannot recreate natural, intuitive sensations. Here, we establish an experimental biological sensorimotor interface and demonstrate its potential use in neuroprosthetics. We transfer a mixed nerve to a skeletal muscle combined with glabrous dermal skin transplantation, thus forming a bi-directional communication unit in a rat model. Morphological analyses indicate reinnervation of the skin, mechanoreceptors, NMJs, and muscle spindles. Furthermore, sequential retrograde labeling reveals specific sensory reinnervation at the level of the dorsal root ganglia. Electrophysiological recordings show reproducible afferent signals upon tactile stimulation and tendon manipulation. The results demonstrate the possibility of surgically creating an interface for both decoding efferent motor control, as well as encoding afferent tactile and proprioceptive feedback, and may indicate the way forward regarding clinical translation of biological communication pathways for neuroprosthetic applications.
Topics: Animals; Bionics; Rats; Muscle, Skeletal; Feedback, Sensory; Proprioception; Ganglia, Spinal; Mechanoreceptors; Muscle Spindles; Male; Female; Touch; Skin
PubMed: 38914540
DOI: 10.1038/s41467-024-49580-8