Central Canal Research Articles

The periaxonal space as a conduit for cerebrospinal fluid flow to peripheral organs

Mechanisms controlling the movement of the cerebrospinal fluid (CSF) toward peripheral nerves are poorly characterized. We found that, in addition to the foramina Magendie and Luschka for CSF flow toward the subarachnoid space and glymphatic system, CSF outflow could also occur along periaxonal spaces (termed "PAS pathway") from the spinal cord to peripheral organs, such as the liver and pancreas. When interrogating the latter route, we found that serotonin, acting through 5-HT2B receptors expressed in ependymocytes that line the central canal, triggered Ca2+ signals to induce polymerization of F-actin, a cytoskeletal protein, to reduce the volume of ependymal cells. This paralleled an increased rate of PAS-mediated CSF redistribution toward peripheral organs. In the liver, CSF was received by hepatic stellate cells. CSF efflux toward peripheral organs through the PAS pathway represents a mechanism dynamically connecting the nervous system with the periphery. Our findings are compatible with the traditional theory of CSF efflux into the glymphatic system to clear metabolic waste from the cerebral parenchyma. Thus, we extend the knowledge of CSF flow and expand the understanding of connectivity between the CNS and peripheral organs.

Cervical Myeloradiculopathy With Bilateral Foraminal Stenosis Treated by Unilateral Biportal Endoscopic Decompression with Alternating Hemilaminectomy and Bilateral foraminotomy: A Case Report and Technical Note

Cervical myeloradiculopathy is a debilitating condition characterized by progressive spinal cord dysfunction commonly caused by degenerative changes in the cervical spine. It typically exhibits an insidious onset and progressive functional decline, along with multiple exiting nerve root entrapments bilaterally in some patients. Traditional surgical interventions, such as discectomy and fusion, are associated with some complications and limitations. Unilateral biportal endoscopic (UBE) decompression can have significant advantages over traditional techniques when cervical central and bilateral foraminal decompression is required. In this case report and technical note, we describe our experience with this novel surgical technique for the treatment of cervical myelopathy. A 67-year-old patient presented with progressive neck pain; bilateral upper extremity radiculopathy; loss of power and sensation in the C5, C6, and C7 nerve root distribution; gait imbalance, and spasticity. Magnetic resonance imaging revealed multilevel cervical spondylosis with central canal and bilateral foraminal stenosis. The patient underwent UBE central and bilateral foraminal decompression. At a 9-month follow-up visit, he was able to walk unassisted, his reflexes had returned to normal, no spasticity was observed, and he had good grip strength in both hands. This is a novel technique of UBE decompression with bilateral foraminotomy at the C4–5, C5–6, and C6–7 levels and laminectomy named “the floating tip technique.” The procedure involved bilateral 3-level lamino-foraminotomy and hemilaminotomy on both C5 and C6. A hemilamina was removed on the opposite sides, and flavectomy was performed. Postoperative computed tomography findings showed an intact, complete muscular mass with an intact central spinous process. Therefore, this method was labelled the “floating tip technique.”

Utility of cervical dynamic magnetic resonance imaging for evaluating patients with cervical myelopathy: a retrospective study.

Retrospective observational study. This study aimed to evaluate the utility of cervical dynamic magnetic resonance imaging (dMRI) in the assessment of cervical canal stenosis. Cervical spondylotic myelopathy has been intricately linked to both static and dynamic narrowing of the cervical spinal canal. Traditional MRI with the neck in a neutral position fails to identify the dynamic changes and may lead to misdiagnosis. Cervical dMRI is a promising tool for evaluating cervical myelopathy, enabling clinicians to assess spinal cord compression, segmental instability, and alterations in range of motion, often missed on conventional imaging. A retrospective analysis was conducted on 369 patients with symptoms of cervical myelopathy assessed using cervical dMRI. After assessing the subaxial cervical spine at each disc level (C3-T1), significant changes in the degree of central canal stenosis were determined. The appearance and extent of hyperintense lesions on T2-weighted sequences were also noted. Overall, 653/1,845 (35.39%) disc levels showed an increase in stenosis grade on extension MRI, with 168/653 (25.72%) and 180/653 (27.56%) disc levels changing from grades 0/1 to grades 2 and 3, respectively. Moreover, 120/369 (32.52%) patients showed a mean increase of 1.55±0.75 levels of compression on extension MRI when compared to neutral MRI. A fresh-appearing hyperintense lesion was observed in 79 (4.28%) disc levels on flexion MRI, which was not visualized on neutral MRI. Cervical dMRI may help surgeons plan for surgery, discuss the prognosis with the patient, and safeguard themselves from medico-legal issues arising from improper or missed diagnosis and treatment.

Performance of Artificial Intelligence in Diagnosing Lumbar Spinal Stenosis: A Systematic Review and Meta-analysis.

The present study followed the reporting guidelines for systematic reviews and meta-analyses. Therefore, we conducted this study to review the diagnostic value of AI for various types of LSS and the level of stenosis, offering evidence-based support for the development of smart diagnostic tools. Artificial intelligence (AI) is currently being utilized for image processing in clinical practice. Some studies have explored AI techniques for identifying the severity of lumbar spinal stenosis (LSS) in recent years. Nevertheless, there remains a shortage of structured data proving its effectiveness. Four databases (PubMed, Cochrane, Embase, and Web of Science) were searched until March 2024, including original studies that utilized deep learning and machine learning models to diagnose LSS. The risk of bias (RoB) of included studies was assessed using QUADAS-2. The accuracy in the validation set was extracted for a meta-analysis. The meta-analysis was completed in R4.4.0. A total of 48 articles were included, with an overall accuracy of 0.885 (95% CI: 0.860-0907) for dichotomous tasks. Among them, the accuracy was 0.892 (95% CI: 0.867-0915) for deep learning (DL) and 0.833 (95% CI: 0.760-0895) for machine learning (ML). The overall accuracy for LSS was 0.895 (95% CI: 0.858-0927), with an accuracy of 0.912 (95% CI: 0.873-0.944) for DL and 0.843 (95% CI: 0.766-0.907) for ML. The overall accuracy for central canal stenosis was 0.875 (95% CI: 0.821-0920), with an accuracy of 0.881 (95% CI: 0.829-0.925) for DL and 0.733 (95% CI: 0.541-0.877) for ML. The overall accuracy for neural foramen stenosis was 0.893 (95% CI: 0.851-0.928). In polytomous tasks, the accuracy was 0.936 (95% CI: 0.895-0.967) for no LSS, 0.503 (95% CI: 0.391-0.614) for mild LSS, 0.512 (95% CI: 0.336-0.688) for moderate LSS, and 0.860 for severe LSS (95% CI: 0.733-0.954). AI is highly valuable for diagnosing LSS. However, further external validation is necessary to enhance the analysis of different stenosis categories and improve the diagnostic accuracy for mild to moderate stenosis levels.

Treatment Strategies for Unknown Anatomic Pathology Ventriculus Terminalis Case Series: Single Center Experience

The ventriculus terminalis is a cavity in the conus medullaris, bounded by ependymal cells, associated with the central canal. It is an anatomical structure that is very rare in adults, with a limited number of surgical cases that have been reported in the literature. In children, it is regarded as a normal congenital variation, known to regress before five years of age, and very few symptomatic cases have been reported in both pediatric and adult populations. It is often asymptomatic in adults and is detected incidentally. Although potentially nonsignificant individually, symptoms can range from nonspecific low back pain to sphincter dysfunction and focal neurologic deficits. Our purpose is to discuss our management strategy in comparison to the existing literature. A retrospective review was conducted of all adult patients (aged 17 years and older) diagnosed with ventriculus terminalis who were referred to the hospital between 2010 and 2020. Clinical classification was made according to the classification defined by Batista. In addition, Ganau's classification was also used. Five patients were included in the study. The majority of these patients (n=4, 80%) were symptomatic at the time of diagnosis, with nonspecific back pain being the most common symptom (n=3, (60%). None of the patients required neurosurgical intervention during the follow-up period of 21.6±8.9 months, as there was no clinical deterioration observed. Ventriculus terminalis is a rare pathology that may develop de novo in adults, often remaining undiagnosed until the cyst enlarges, and can manifest with a wide spectrum of symptoms. When identified, it requires careful management, involving surgery when necessary and a conservative approach when appropriate.

To validate and correlate radiologic grading of central and foraminal stenosis post-surgical decompression on degenerative lumbar canal stenosis

Background: Lumbar canal stenosis (LCS) is characterized as a narrowing of the canal diameter with age, which can lead to degenerative bone and soft-tissue changes. Aims and Objectives: The aim of the study is to validate the radiologic grading of central and foraminal through correlation with outcome after surgical decompression in degenerative LCS. Materials and Methods: A total of 23 patients with degenerative LCS who satisfied inclusion criteria and consented to participate in the study were selected and their Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) for back and leg pain were recorded and their magnetic resonance imaging (MRI) was graded. Results: LCS is the reduction in the dimension of the central or lateral lumbar canal that occurs most frequently as a result of chronic degenerative changes at the lumbar motion segments. In our study, ODI has comparable improvement in all groups and it does not correlate with the severity of stenosis. However, VAS for leg pain has a greater prevalence in the shorter durations group (<60 months) which had an average of 8.0. If VAS for leg pain was more preoperatively, a better outcome was seen postoperatively. Conclusion: Decompression surgery for degenerative LCS shows significant improvement in ODI and VAS for back pain and leg pain irrespective of the severity of the stenosis by MRI grading or the severity of symptoms as assessed by VAS or ODI.

External Validation of SpineNetV2 on a Comprehensive Set of Radiological Features for Grading Lumbosacral Disc Pathologies

BackgroundIn recent years, the integration of Artificial Intelligence (AI) models has revolutionized the diagnosis of Low Back Pain (LBP) and associated disc pathologies. Among these, SpineNetV2 stands out as a state-of-the-art, open-access model for detecting and grading various intervertebral disc pathologies. However, ensuring the reliability and applicability of AI models like SpineNetV2 is paramount. Rigorous validation is essential to guarantee their robustness and generalizability across diverse patient cohorts and imaging protocols. MethodsWe conducted a retrospective analysis of MRI images of 1747 lumbosacral intervertebral discs (IVDs) from 353 patients (mean age, 54 ± 15.4 years, 44.5% female) with various spinal disorders, collected between September 2021 and February 2023 at X-Ray Service s.r.l. The SpineNetV2 system was used to grade 11 distinct lumbosacral disc pathologies, including Pfirrmann grading, disc narrowing, central canal stenosis, spondylolisthesis, (upper & lower) endplate defects, (upper & lower) marrow changes, (right & left) foraminal stenosis, and disc herniation, using T2-weighted sagittal MR images. Performance metrics included accuracy, balanced accuracy, precision, F1 score, Matthew's Correlation Coefficient, Brier Score Loss, Lin's concordance correlation coefficients, and Cohen's kappa coefficients. Two expert radiologists provide annotations for these discs. The evaluation of SpineNetV2′s grading is compared against expert radiologists' assessments. ResultsSpineNetV2 demonstrated strong performance across various metrics, with high agreement scores (Cohen's Kappa, Lin's Concordance, and Matthew's Correlation Coefficient exceeding 0.7) for most pathologies. However, lower agreement was found for foraminal stenosis and disc herniation, underscoring the limitations of sagittal MR images for evaluating these conditions. ConclusionsThis study highlights the importance of external validation, emphasizing the need for comprehensive assessments of deep learning models. SpineNetV2 exhibits promising results in predicting disc pathologies, with findings guiding further improvements. The open-source release of SpineNetV2 enables researchers to independently validate and extend the model's capabilities. This collaborative approach promotes innovation and accelerates the development of more reliable and comprehensive deep learning tools for the assessment of spine pathology.

AI-based lumbar central canal stenosis classification on sagittal MR images is comparable to experienced radiologists using axial images

Abstract Objectives The assessment of lumbar central canal stenosis (LCCS) is crucial for diagnosing and planning treatment for patients with low back pain and neurogenic pain. However, manual assessment methods are time-consuming, variable, and require axial MRIs. The aim of this study is to develop and validate an AI-based model that automatically classifies LCCS using sagittal T2-weighted MRIs. Methods A pre-existing 3D AI algorithm was utilized to segment the spinal canal and intervertebral discs (IVDs), enabling quantitative measurements at each IVD level. Four musculoskeletal radiologists graded 683 IVD levels from 186 LCCS patients using the 4-class Lee grading system. A second consensus reading was conducted by readers 1 and 2, which, along with automatic measurements, formed the training dataset for a multiclass (grade 0–3) and binary (grade 0–1 vs. 2–3) random forest classifier with tenfold cross-validation. Results The multiclass model achieved a Cohen’s weighted kappa of 0.86 (95% CI: 0.82–0.90), comparable to readers 3 and 4 with 0.85 (95% CI: 0.80–0.89) and 0.73 (95% CI: 0.68–0.79) respectively. The binary model demonstrated an AUC of 0.98 (95% CI: 0.97–0.99), sensitivity of 93% (95% CI: 91–96%), and specificity of 91% (95% CI: 87–95%). In comparison, readers 3 and 4 achieved a specificity of 98 and 99% and sensitivity of 74 and 54%, respectively. Conclusion Both the multiclass and binary models, while only using sagittal MR images, perform on par with experienced radiologists who also had access to axial sequences. This underscores the potential of this novel algorithm in enhancing diagnostic accuracy and efficiency in medical imaging. Key Points QuestionHow can the classification of lumbar central canal stenosis (LCCS) be made more efficient? FindingsMulticlass and binary AI models, using only sagittal MR images, performed on par with experienced radiologists who also had access to axial sequences. Clinical relevanceOur AI algorithm accurately classifies LCCS from sagittal MRI, matching experienced radiologists. This study offers a promising tool for automated LCCS assessment from sagittal T2 MRI, potentially reducing the reliance on additional axial imaging.

Endogenous opioid signalling regulates spinal ependymal cell proliferation.

After injury, mammalian spinal cords develop scars to confine the lesion and prevent further damage. However, excessive scarring can hinder neural regeneration and functional recovery1,2. These competing actions underscore the importance of developing therapeutic strategies to dynamically modulate scar progression. Previous research on scarring has primarily focused on astrocytes, but recent evidence has suggested that ependymal cells also participate. Ependymal cells normally form the epithelial layer encasing the central canal, but they undergo massive proliferation and differentiation into astroglia following certain injuries, becoming a core scar component3-7. However, the mechanisms regulating ependymal proliferation in vivo remain unclear. Here we uncover an endogenous κ-opioid signalling pathway that controls ependymal proliferation. Specifically, we detect expression of the κ-opioid receptor, OPRK1, in a functionally under-characterized cell type known as cerebrospinal fluid-contacting neuron (CSF-cN). We also discover a neighbouring cell population that expresses the cognate ligand prodynorphin (PDYN). Whereas κ-opioids are typically considered inhibitory, they excite CSF-cNs to inhibit ependymal proliferation. Systemic administration of a κ-antagonist enhances ependymal proliferation in uninjured spinal cords in a CSF-cN-dependent manner. Moreover, a κ-agonist impairs ependymal proliferation, scar formation and motor function following injury. Together, our data suggest a paracrine signalling pathway in which PDYN+ cells tonically release κ-opioids to stimulate CSF-cNs and suppress ependymal proliferation, revealing an endogenous mechanism and potential pharmacological strategy for modulating scarring after spinal cord injury.

Feasibility of deep learning algorithm in diagnosing lumbar central canal stenosis using abdominal CT.

To develop a deep learning algorithm for diagnosing lumbar central canal stenosis (LCCS) using abdominal CT (ACT) and lumbar spine CT (LCT). This retrospective study involved 109 patients undergoing LCTs and ACTs between January 2014 and July 2021. The dural sac on CT images was manually segmented and classified as normal or stenosed (dural sac cross-sectional area ≥ 100 mm2 or < 100 mm2, respectively). A deep learning model based on U-Net architecture was developed to automatically segment the dural sac and classify the central canal stenosis. The classification performance of the model was compared on a testing set (990 images from 9 patients). The accuracy, sensitivity, and specificity of automatic segmentation were quantitatively evaluated by comparing its Dice similarity coefficient (DSC) and intraclass correlation coefficient (ICC) with those of manual segmentation. In total, 990 CT images from nine patients (mean age ± standard deviation, 77 ± 7years; six men) were evaluated. The algorithm achieved high segmentation performance with a DSC of 0.85 ± 0.10 and ICC of 0.82 (95% confidence interval [CI]: 0.80,0.85). The ICC between ACTs and LCTs on the deep learning algorithm was 0.89 (95%CI: 0.87,0.91). The accuracy of the algorithm in diagnosing LCCS with dichotomous classification was 84%(95%CI: 0.82,0.86). In dataset analysis, the accuracy of ACTs and LCTs was 85%(95%CI: 0.82,0.88) and 83%(95%CI: 0.79,0.86), respectively. The model showed better accuracy for ACT than LCT. The deep learning algorithm automatically diagnosed LCCS on LCTs and ACTs. ACT had a diagnostic performance for LCCS comparable to that of LCT.

Multicentre investigation on the effect of decompressive surgery on Balance and physical ActiviTy Levels amongst patients with lumbar Spinal stenosis (B-ATLAS): protocol for a prospective cohort study

IntroductionPatients with lumbar spinal stenosis may have poor balance, decreased physical function and problems maintaining physical activity levels due to radiculopathy. Decompressive surgery is often indicated if conservative management fails...

The annoyance of singultus: a case report of a rare adverse effect after epidural steroid injection

ObjectiveCervical epidural steroid injections (ESIs) can provide effective pain management for patients suffering from chronic neck pain due to various pathological changes of the cervical spine. There are several rare adverse effects reported from interventional pain procedures, including persistent hiccups (“singultus”). Based on a limited number of cases, we propose a modified treatment algorithm for this adverse outcome (Fig. 3).Case reportSingultus has been documented as an adverse effect of interventional pain procedures, including epidural steroid, facet joint, and sacroiliac joint injections. We describe the case of a general contractor who presented to our clinic with chronic neck pain and central canal stenosis. The patient received an uncomplicated lumbar ESI in the past and was recommended for a cervical interlaminar ESI. After an uneventful C6-C7 interlaminar ESI with dexamethasone, 1% lidocaine, and normal saline the patient developed singultus. Baclofen was sent to his pharmacy, but this was unsuccessful at alleviating his hiccups. The patient was subsequently started on chlorpromazine and found relief from his symptomatology.ConclusionPersistent hiccups after ESI or interventional pain procedures can be treated with conservative measures and non-pharmacologic methods, with escalation to therapy with baclofen, gabapentin, pregabalin, metoclopramide, chlorpromazine, other antipsychotic or antidopaminergic agents, and possible dual or triple therapy if further indicated.

Nanobots: An endodontist saviour.

The application of nanoparticles in the form of solution for irrigation, medication and as an additive for sealer/restorative material has been evaluated to improve the antibacterial efficacy in the field of endodontics. Recently developed nanobots are injected into the teeth to destroy pathogens and they are more effective in root canal therapy. They are helical shaped and composed of silicon dioxide with iron embedded into the silica body to provide magnetic properties. They are also able to move within the dentinal tubules and are manipulated peripherally through a low-intensity magnetic field. These nanobots can be administered into the cleaned central canal of a tooth samples which are immersed in deionized water and their motions are monitored using a near-infrared imaging technique to produce heat which is a hyperthermia-based bactericidal method which help to eradicate the surrounding pathogens.

A high-fat diet influences neural stem and progenitor cell environment in the medulla of adult mice

It has been widely established that neural stem cells (NSCs) exist in the adult mammalian brain. The area postrema (AP) and the ependymal cell layer of the central canal (CC) in the medulla were recently identified as NSC niches. There are two types of NSCs: astrocyte-like cells in the AP and tanycyte-like cells in the CC. However, limited information is currently available on the characteristics and functional significance of these NSCs and their progeny in the AP and CC. The AP is a part of the dorsal vagal complex (DVC), together with the nucleus of the solitary tract (Sol) and the dorsal motor nucleus of the vagus (10 N). DVC is the primary site for the integration of visceral neuronal and hormonal cues that act to inhibit food intake. Therefore, we examined the effects of high-fat diet (HFD) on NSCs and progenitor cells in the AP and CC. Eight-week-old male mice were fed HFD for short (1 week) and long periods (4 weeks). To detect proliferating cells, mice consecutively received intraperitoneal injections of BrdU for 7 days. Brain sections were processed with immunohistochemistry using various cell markers and BrdU antibodies. Our data demonstrated that adult NSCs and neural progenitor cells (NPCs) in the medulla responded more strongly to short-term HFD than to long-term HFD. HFD increased astrocyte density in the Sol and 10 N, and increased microglial/macrophage density in the AP and Sol. Furthermore, long-term HFD induced mild inflammation in the medulla, suggesting that it affected the proliferation of NSCs and NPCs.

Anatomic Parameters for Diagnosing Congenital Lumbar Stenosis Based on Computed Tomography of 1,000 Patients.

Quantitative parameters for diagnosis of congenital lumbar stenosis (CLS) have yet to be universally accepted. This study establishes parameters for CLS using CT, assessing the influences of patient sex, race, ethnicity, and anthropometric characteristics. Interpedicular distance (IPD), pedicle length, canal diameter, and canal area were measured using 1,000 patients between 18 and 35 years of age who were without spinal pathology. Irrespective of disk level, threshold values for CLS were 16.1 mm for IPD, 3.9 mm for pedicle length, 11.5 mm for canal diameter, and 142.5 mm2 for canal area. Notable differences based on patient sex were observed, with men demonstrating larger CLS threshold values with respect to IPD and canal area across all vertebral levels from L1 to L5. Based on patient anthropometric factors, no strong or moderate associations were observed between any spinal measurement and patient height, weight, or body mass index across all levels from L1 to L5. However, notable differences were observed based on patient race and ethnicity from L1 to L5. Asian patients demonstrated the largest pedicle lengths, followed by White, Hispanic, and Black patients in descending order. White patients demonstrated the largest IPD, canal AP diameter, and canal area, followed by Asian, Hispanic, and Black patients in descending order. Black patients demonstrated the smallest values across all anatomic measurements relative to Asian, White, and Hispanic patients. This study reports 25,000 measurements of lumbar central canal dimensions to establish quantitative thresholds for the diagnosis of CLS. Although not influenced by patient height, weight, or body mass index as one might intuit, canal dimensions were influenced by patient sex, race, and ethnicity. These findings may help explain differences in predisposition or prevalence of lumbar nerve root compression among patients of different races, which can be important when considering rates of surgery and access to care.

A comparative assessment of age-related nicotinamide adenine dinucleotide phosphate-diaphorase positivity in the spinal cord and medulla oblongata of pigeons, rats, and mice.

Nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase (N-d) positive neurons have been extensively studied across various animals, and N-d neurodegenerative neurites have been detected in some aged animal models. However, detailed knowledge on N-d positivity and aging-related alterations in the spinal cord and medulla oblongata of pigeons is limited. In this study, we investigated N-d positivity and age-related changes in the pigeon's spinal cord and medulla oblongata and compared them to those in rats and mice. Pigeons, had more N-d neurons in the dorsal horn, around the central canal, and in the column of Terni in the thoracic and lumbar segments, with scattered neurons found in the ventral horn of the spinal segments. N-d neurons were also present in the white matter of the spinal cord. Morphometric analysis revealed that the size of N-d soma in the lumbosacral, cervical, and thoracic regions was substantially altered in aged pigeons compared to young birds. Furthermore, the lumbar to sacral segments underwent significant morphological alterations. The main findings of this study were the presence of age-related N-d positive bodies (ANB) in aged pigeons, predominantly in the external cuneate nucleus (CuE) and occasionally in the gracilis and CuEs. ANBs were also identified in the gracile nuclei and spinal cord in the aged rats and mice, whereas in aged rats, ANBs were detected in the CuE spinal nucleus. Immunohistochemistry showed that the age-related alterations occurred in the cell types and neuropeptides in old animals. The results suggest weak inflammatory response and neuronal dysfunction in the spinal cord in aged pigeons. Our results suggested that the ANB could be a potential aging marker for the central nervous system.

Diffuse, bilateral intraventricular spread of an oligodendroglioma in a Boxer dog

AbstractA case of a high‐grade oligodendroglioma in a boxer dog is presented. Using magnetic resonance imaging, a parenchymal lesion was noted entering into the ventrocaudal, right lateral ventricle. Magnetic resonance imaging showed the mass had extensive, contiguous spread rostrally through the lateral ventricles, and caudally into the third and fourth ventricles, and central canal. This was confirmed with histopathology. This degree of invasion in the ventricles by an oligodendroglioma has not been reported and indicates that oligodendrogliomas should be included as a differential diagnosis for intraventricular tumours with bilateral, contiguous invasion of the ventricular system.

Approach for Electrophysiological Studies of Spinal Lamina X Neurons.

Despite playing diverse physiological roles, the area surrounding the central canal, lamina X, remains one of the least studied spinal cord regions. Technical challenges and limitations of the commonly used experimental approaches are the main difficulties that hamper lamina X research. In the current protocol, we describe a reliable method for functional investigation of lamina X neurons that requires neither time-consuming slicing nor sophisticated in vivo experiments. Our approach relies on ex vivo hemisected spinal cord preparation that preserves the rostrocaudal and mediolateral spinal architecture as well as the dorsal roots, and infrared LED oblique illumination for visually guided patch clamp in thick blocks of tissue. When coupled with electric stimulation of the spared dorsal roots, electrophysiological recordings provide information on primary afferent inputs to lamina X neurons from myelinated and non-myelinated fibers and allow estimating primary afferent-driven presynaptic inhibition. Overall, we describe a simple, time-efficient, inexpensive, and versatile approach for lamina X research. Key features • Quick and easy preparation procedure that grants access to lamina X neurons without spinal cord slicing • Preserved rostrocaudal and mediolateral connectivity and preserved primary afferent supply • Ability to perform electrophysiological recordings in combination with dorsal root stimulations allowing to study afferent inputs and presynaptic inhibition of lamina X neurons.

Assessment of Anteroposterior Diameter and Interpedicular Distance in the Approximation of Cervical Spinal Canal Area.

Rationale and objectives This study seeks to generate a model based on two linear measurements, anteroposterior (AP) diameter and interpedicular (IPD) distance, to approximate the cervical central canal (CCC) area in a non-pathologic patient population by employing area calculations of shapes such as ellipse, rectangle, and triangle. Secondarily, this study aims to generate second-order approximations (SOAs), using the aforementioned shape approximations, to increase the utility of this linear measurement-based model. Methods The authors reviewed medical and radiographic records of patients aged 18-35 who received computed tomography (CT) imaging of the cervical spine to collect AP diameter, IPD distance, and area of the CCC from C2-3 to C6-7. Subsequently, shape approximations were calculated for each patient at all cervical spine levels. Lastly, SOAs were generated by combining optimal ratios of shape approximations to improve the statistical reliability of approximations. Results The ellipse shows the closest approximation to manual measurements of the individual shape approximations. Percent error analysis demonstrated the superiority of the ellipse, followed by the rectangle, and lastly the triangular approximation. The highest correlation of approximations was observed at C6-7. All individual shape approximations demonstrated statistical differences from manual measurements. SOAs combining ellipse and rectangle measurements demonstrated superior accuracy and were not statistically different from manual measurements. Conclusion Individual shape approximations based on AP diameter and IPD distance show some value as a model for the assessment of the CCC area. SOAs demonstrated greater utility than individual shape approximations and show promise as a linear measurement-based tool to assess the CCC area.

Influencing Factors for the Growth of Cladophora and Its Cell Damage and Destruction Mechanism: Implication for Prevention and Treatment

Cladophora is commonly found in marine and freshwater around the globe and provides productivity for littoral zone microorganisms and invertebrates. The eutrophication of the water body has led to the abnormal proliferation of Cladophora in some water, often in river coast channel outbreaks. Even under the nutritional deficiency systems, such as the central trunk canal of the South-to-North Water Diversion in China, Cladophora’s blooms affect water quality and seriously jeopardize human health. Thus, the structural characteristics of Cladophora cells and spores, the factors affecting the growth of Cladophora cells, and the mechanisms of damage and destruction of Cladophora cells and spores were investigated. Cladophora cells are cylindrical with very thick cell walls. The inner layer of the spore wall is a thin membrane which contains the nucleus of the spore. The growth and spreading of Cladophora cells are affected by various environmental factors such as light, temperature, water depth, water level, nutrient salts, pH, etc. Some physical treatment measures, such as ultrasounds, would destroy the cell walls and membranes of Cladophora by its high-intensity mechanical action. Chemicals and aquatic plant measures can destroy Cladophora cells’ photosynthesis system, antioxidant enzyme systems, proteins, and ultrastructure. Based on the mechanisms for these cell damage and destruction, a combination of measures that are likely to inhibit the growth of Cladophora cells effectively was suggested. Furthermore, the damaged cells of Cladophora could provide some environmental benefits. Aggregated results could provide a scientific basis for further research on the control of blooms of Cladophora or the reuse of Cladophora cells as a natural resource.