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Pflugers Archiv : European Journal of... Apr 2022Sensory neurons are responsible for the generation and transmission of nociceptive signals from the periphery to the central nervous system. They encompass a broadly... (Review)
Review
Sensory neurons are responsible for the generation and transmission of nociceptive signals from the periphery to the central nervous system. They encompass a broadly heterogeneous population of highly specialized neurons. The understanding of the molecular choreography of individual subpopulations is essential to understand physiological and pathological pain states. Recently, it became evident that species differences limit transferability of research findings between human and rodents in pain research. Thus, it is necessary to systematically compare and categorize the electrophysiological data gained from human and rodent dorsal root ganglia neurons (DRGs). In this systematic review, we condense the available electrophysiological data defining subidentities in human and rat DRGs. A systematic search on PUBMED yielded 30 studies on rat and 3 studies on human sensory neurons. Defined outcome parameters included current clamp, voltage clamp, cell morphology, pharmacological readouts, and immune reactivity parameters. We compare evidence gathered for outcome markers to define subgroups, offer electrophysiological parameters for the definition of neuronal subtypes, and give a framework for the transferability of electrophysiological findings between species. A semiquantitative analysis revealed that for rat DRGs, there is an overarching consensus between studies that C-fiber linked sensory neurons display a lower action potential threshold, higher input resistance, a larger action potential overshoot, and a longer afterhyperpolarization duration compared to other sensory neurons. They are also more likely to display an infliction point in the falling phase of the action potential. This systematic review points out the need of more electrophysiological studies on human sensory neurons.
Topics: Action Potentials; Animals; Electrophysiological Phenomena; Ganglia, Spinal; Humans; Pain; Rats; Sensory Receptor Cells
PubMed: 35031856
DOI: 10.1007/s00424-021-02656-6 -
The Cochrane Database of Systematic... Jan 2017Glaucoma is a heterogeneous group of conditions involving progressive damage to the optic nerve, deterioration of retinal ganglion cells, and ultimately visual field... (Review)
Review
BACKGROUND
Glaucoma is a heterogeneous group of conditions involving progressive damage to the optic nerve, deterioration of retinal ganglion cells, and ultimately visual field loss. It is a leading cause of blindness worldwide. Open angle glaucoma (OAG), the most common form of glaucoma, is a chronic condition that may or may not present with increased intraocular pressure (IOP). Neuroprotection for glaucoma refers to any intervention intended to prevent optic nerve damage or cell death.
OBJECTIVES
The objective of this review was to systematically examine the evidence regarding the effectiveness of neuroprotective agents for slowing the progression of OAG in adults compared with no neuroprotective agent, placebo, or other glaucoma treatment.
SEARCH METHODS
We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 7), Ovid MEDLINE, Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Ovid MEDLINE Daily (January 1946 to August 2016), Embase (January 1980 to August 2016), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to August 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 16 August 2016.
SELECTION CRITERIA
We included randomised controlled trials (RCTs) in which topical or oral treatments were used for neuroprotection in adults with OAG. Minimum follow-up time was four years.
DATA COLLECTION AND ANALYSIS
Two review authors independently reviewed titles and abstracts from the literature searches. We obtained full-text copies of potentially relevant studies and re-evaluated for inclusion. Two review authors independently extracted data related to study characteristics, risk of bias, and outcomes. We identified one trial for this review, thus we performed no meta-analysis. Two studies comparing memantine to placebo are currently awaiting classification until study investigators provide additional study details. We documented reasons for excluding studies from the review.
MAIN RESULTS
We included one multicenter RCT of adults with low-pressure glaucoma (Low-pressure Glaucoma Treatment Study, LoGTS) conducted in the USA. The primary outcome was progression of visual field loss after four years of treatment with either brimonidine or timolol. Of the 190 adults enrolled in the study, the investigators excluded 12 (6.3%) after randomization; 77 participants (40.5%) did not complete four years of follow-up. The rate of attrition was unbalanced between groups with more participants dropping out of the brimonidine group (55%) than the timolol group (29%).Of those remaining in the study at four years, participants assigned to brimonidine showed less progression of visual field loss than participants assigned to timolol (risk ratio (RR) 0.35, 95% confidence interval (CI) 0.14 to 0.86; 101 participants). Because of high risk of attrition bias and potential selective outcome reporting, we graded the certainty of evidence for this outcome as very low. At the four-year follow-up, the mean IOP was similar in both groups among those for whom data were available (mean difference 0.20 mmHg, 95% CI -0.73 to 1.13; 91 participants; very low-certainty evidence). The study authors did not report analyzable data for visual acuity or any data related to vertical cup-disc ratio, quality of life, or economic outcomes. The most frequent adverse event was ocular allergy to the study drug, which affected more participants in the brimonidine group than the timolol group (RR 5.32, 95% CI 1.64 to 17.26; 178 participants; very low-certainty evidence).
AUTHORS' CONCLUSIONS
Although the only trial we included in this review found less visual field loss in the brimonidine-treated group, the evidence was of such low certainty that we can draw no conclusions from this finding. Further clinical research is needed to determine whether neuroprotective agents may be beneficial for individuals with OAG. Such research should focus on outcomes important to patients, such as preservation of vision, and how these outcomes relate to cell death and optic nerve damage. As OAG is a chronic, progressive disease with variability in symptoms, RCTs designed to measure the effectiveness of neuroprotective agents require a long-term follow-up of five years or longer to detect clinically meaningful effects.
Topics: Adult; Antihypertensive Agents; Brimonidine Tartrate; Disease Progression; Glaucoma, Open-Angle; Humans; Neuroprotective Agents; Optic Nerve; Optic Nerve Diseases; Randomized Controlled Trials as Topic; Retinal Ganglion Cells; Timolol
PubMed: 28122126
DOI: 10.1002/14651858.CD006539.pub4 -
Acta Ophthalmologica Mar 2018To evaluate the role of neural integrators (NI) in the oculomotor system. (Review)
Review
PURPOSE
To evaluate the role of neural integrators (NI) in the oculomotor system.
METHODS
A literature search was carried out using several electronic databases during the months of June 2014 to March 2015. The following keywords were used to generate focused results: 'neural integrators', 'gaze-holding', 'oculomotor integration', 'impaired gaze-holding', 'gaze evoked nystagmus' and 'gaze dysfunction'. Further materials were found through searching relevant articles within reference lists. Seventy-one articles were sourced for this review which analysed animal and human subjects and network models; 45 were studies of humans, 16 studies of primates, three studies of felines and one study from rats and network models. The remaining articles were literature reviews.
RESULTS
The horizontal and vertical, including torsional, NI are located logically in the brainstem, nearby their appropriate target extraocular motoneuron nuclei for stable eye position in eccentric position. The nucleus prepositus hypoglossi (NPH) and medial vestibular nuclei (MVN) are closely linked at the caudal pons and dorsal rostral medulla, integrating horizontal conjugate eye movement. The interstitial nucleus of Cajal (INC) integrates vertical and torsional eye movement at the upper midbrain. The integrator time constant is averaged to 25 seconds in human horizontal and animal vertical NI to perform its function. Case reports revealed that dysfunction of horizontal NI also resulted in vertical ocular deviations, indicating some overlap of horizontal and vertical gaze control. Furthermore, pharmacological inactivation of NI exposed a population of inhibitory neurotransmitters that permits its mechanism of action; allowing for smooth conjugate movement.
CONCLUSIONS
Neural integrators operate to integrate eye velocity and eye position information to provide signals to extraocular motoneurons to attain and maintain a new position. Therefore, NI allow image stabilization during horizontal and vertical eye movements at eccentric positions for comfortable single vision.
Topics: Animals; Eye Movements; Fixation, Ocular; Humans; Oculomotor Nerve; Sensory Receptor Cells; Visual Fields
PubMed: 27874249
DOI: 10.1111/aos.13307 -
Eye (London, England) Mar 2021The purpose of this study is to systematically review the reported data of normal optical coherence tomography (OCT) results in the paediatric population. A systematic... (Review)
Review
The purpose of this study is to systematically review the reported data of normal optical coherence tomography (OCT) results in the paediatric population. A systematic literature search was performed using the PubMed, Embase, and Web of Science databases, using the keywords "optical coherence tomography"; "normative data" or "healthy eyes"; "children" or "paediatric population". Studies with at least 50 participants were included, irrespective of the OCT equipment employed. We excluded the OCT angiography studies or the studies investigating the choroidal thickness. Seventy-four studies were included in the final analysis and information on study design, number of participants, demographic characteristics, type of OCT equipment, OCT parameters and results was collected. Due to the high variability of OCT instruments and parameters used, a meta-analysis was not feasible. We report the normative values for the peripapillary retinal nerve fibre layer thickness and the macular retinal thickness for each ETDRS quadrant, as provided by the studies included in the present analysis. We also report the influence of ethnicity, age, gender, eye laterality, ISNT rule, spherical equivalent, and axial length on OCT results.
Topics: Child; Choroid; Cross-Sectional Studies; Humans; Refraction, Ocular; Retina; Retinal Ganglion Cells; Tomography, Optical Coherence
PubMed: 32929184
DOI: 10.1038/s41433-020-01177-3 -
Eye (London, England) Apr 2024Mild traumatic brain injury (mTBI) is common with many patients suffering disabling long-term sequelae, with visual symptoms frequently reported. There are no objective... (Review)
Review
Mild traumatic brain injury (mTBI) is common with many patients suffering disabling long-term sequelae, with visual symptoms frequently reported. There are no objective biomarkers of mTBI that are routinely used in clinical practice. Optical coherence tomography (OCT) has been used in mTBI research, as it enables visualisation of the neuroretina, allowing measurement of the retinal nerve fibre layer and ganglion cell layer. This systematic review aims to appraise the available literature and assess whether there are significant changes within the retinal nerve fibre layer and ganglion cell layer in subjects after mTBI. A systematic review was carried out in accordance with PRISMA guidelines and registered with PROSPERO (Number: CRD42022360498). Four databases were searched for relevant literature published from inception until 1 September 2022. Abstracts and full texts were screened by three independent reviewers. Initial screening of databases yielded 341 publications, of these, three fulfilled all the criteria for inclusion. All three studies showed thinning of the retinal nerve fibre layer, whereas there were no significant changes in the ganglion cell layer. This systematic review demonstrated that thinning of the retinal nerve fibre layer (but not of the ganglion cell layer) is associated with mTBI. It provides preliminary evidence for the use of the retinal nerve fibre layer as a potential biomarker of damage to the visual system in mTBI. Further prospective longitudinal studies ensuring uniform diagnosis and accurate phenotyping of mTBI are needed to understand the effects on the visual system and potential of OCT as a prognostic biomarker.
Topics: Adult; Humans; Retinal Ganglion Cells; Tomography, Optical Coherence; Brain Concussion; Nerve Fibers; Biomarkers
PubMed: 38238577
DOI: 10.1038/s41433-023-02845-w -
Ophthalmic Research 2024Anterior ischemic optic neuropathy (AION) can mimic glaucoma and consequently cause difficulties in differential diagnosis. The purpose of this paper was to summarize... (Review)
Review
INTRODUCTION
Anterior ischemic optic neuropathy (AION) can mimic glaucoma and consequently cause difficulties in differential diagnosis. The purpose of this paper was to summarize differences in diagnostic tests that can help perform a correct diagnosis.
METHODS
The search strategy was performed according to the PRISMA 2009 guidelines, and four databases were used: MEDLINE, Embase, Web of Science, and Cochrane. Totally, 772 references were eligible; 39 were included after screening with respect to inclusion criteria that included English language and published in the 20 years before search date.
RESULTS
Ninety percent (n = 35) of included studies used optical coherence tomography (OCT). Glaucomatous eyes had a significantly greater cup area, volume and depth, cup-to-disk ratio, a lower rim volume and area, and a thinner Bruch's membrane opening-minimum rim width. Retinal nerve fiber layer (RNFL) thinning in glaucomatous eyes occurred primarily at the superotemporal, inferotemporal, and inferonasal sectors, while AION eyes demonstrated mostly superonasal thinning. Glaucoma eyes showed greater macular ganglion cell layer thickness, except at the inferotemporal sector. OCT angiography measurements demonstrated a significant decrease in superficial and deep macular vessel density (VD) in glaucoma compared to AION with similar degree of visual field damage; the parapapillary choroidal VD was spared in AION eyes compared to glaucomatous eyes.
CONCLUSION
By use of OCT imaging, optic nerve head parameters seem most informative to distinguish between glaucoma and AION. Although both diseases affect the RNFL thickness, it seems to do so in different sectors. Differences in structure and vascularity of the macula can also help in making the differential diagnosis.
Topics: Humans; Optic Neuropathy, Ischemic; Diagnosis, Differential; Tomography, Optical Coherence; Nerve Fibers; Retinal Ganglion Cells; Optic Disk; Glaucoma; Visual Fields; Intraocular Pressure
PubMed: 38262372
DOI: 10.1159/000535568 -
Cells Mar 2022Galanin is a neuropeptide expressed in a small percentage of sensory neurons of the dorsal root ganglia and the superficial lamina of the dorsal horn of the spinal cord.... (Review)
Review
Galanin is a neuropeptide expressed in a small percentage of sensory neurons of the dorsal root ganglia and the superficial lamina of the dorsal horn of the spinal cord. In this work, we systematically reviewed the literature regarding the role of galanin and its receptors in nociception at the spinal and supraspinal levels, as well as in chronic pain conditions. The literature search was performed in PubMed, Web of Science, Scopus, ScienceDirect, OVID, TRIP, and EMBASE using "Galanin" AND "pain" as keywords. Of the 1379 papers that were retrieved in the initial search, we included a total of 141 papers in this review. Using the ARRIVE guidelines, we verified that 89.1% of the works were of good or moderate quality. Galanin shows a differential role in pain, depending on the pain state, site of action, and concentration. Under normal settings, galanin can modulate nociceptive processing through both a pro- and anti-nociceptive action, in a dose-dependent manner. This peptide also plays a key role in chronic pain conditions and its antinociceptive action at both a spinal and supraspinal level is enhanced, reducing animals' hypersensitivity to both mechanical and thermal stimulation. Our results highlight galanin and its receptors as potential therapeutic targets in pain conditions.
Topics: Animals; Chronic Pain; Galanin; Ganglia, Spinal; Sensory Receptor Cells; Spinal Cord
PubMed: 35269462
DOI: 10.3390/cells11050839 -
Lin Chuang Er Bi Yan Hou Tou Jing Wai... Jun 2021As one of the neurotrophic factors and insulin family, insulin like growth factor-1(IGF-1) can promote cell synthesis and metabolism in tissues and organs, activate... (Review)
Review
As one of the neurotrophic factors and insulin family, insulin like growth factor-1(IGF-1) can promote cell synthesis and metabolism in tissues and organs, activate cell growth, proliferation and differentiation, and inhibit cell apoptosis. Sensorineural hearing loss is the most common manifestation of the inner ear disease, which is mainly caused by the damage of cochlear hair cells. The lack of IGF-1 directly affects the growth, development and differentiation of cochlear hair cells, thus IGF-1 participates in the maintenance of cell survival and repair during inner ear cell injury. This article systematically reviews the recent research progress on the protective mechanism of IGF-1 on the inner ear.
Topics: Ear, Inner; Hair Cells, Auditory; Hearing Loss, Sensorineural; Humans; Insulin-Like Growth Factor I; Nerve Growth Factors; Spiral Ganglion
PubMed: 34304523
DOI: 10.13201/j.issn.2096-7993.2021.06.020 -
Pain Physician 2015Chronic neck pain is a common problem with a poorly understood pathophysiology. Often no underlying structural pathology can be found and radiological imaging findings... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Chronic neck pain is a common problem with a poorly understood pathophysiology. Often no underlying structural pathology can be found and radiological imaging findings are more related to age than to a patient's symptoms. Besides its common occurrence, chronic idiopathic neck pain is also very disabling with almost 50% of all neck pain patients showing moderate disability at long-term follow-up. Central sensitization (CS) is defined as "an amplification of neural signaling within the central nervous system that elicits pain hypersensitivity," "increased responsiveness of nociceptive neurons in the central nervous system to their normal or subthreshold afferent input," or "an augmentation of responsiveness of central neurons to input from unimodal and polymodal receptors." There is increasing evidence for involvement of CS in many chronic pain conditions. Within the area of chronic idiopathic neck pain, there is consistent evidence for the presence and clinical importance of CS in patients with traumatic neck pain, or whiplash-associated disorders. However, the majority of chronic idiopathic neck pain patients are unrelated to a traumatic injury, and hence are termed chronic idiopathic non-traumatic neck pain. When comparing whiplash with idiopathic non-traumatic neck pain, indications for different underlying mechanisms are found.
OBJECTIVE
The goal of this article was to review the existing scientific literature on the role of CS in patients with chronic idiopathic non-traumatic neck pain.
STUDY DESIGN
Systematic review.
SETTING
All selected studies were case control studies.
METHODS
A systematic search of existing, relevant literature was performed via the electronic databases Medline, Embase, Web of Science, Cinahl, PubMed, and Google Scholar. All titles and abstracts were checked to identify relevant articles. An article was considered eligible if it met following inclusion criteria: (1) participants had to be human adults (> 18 years) diagnosed with idiopathic non-traumatic chronic (present for at least 3 months) neck pain; (2) papers had to report outcomes related to CS; and (3) articles had to be full-text reports or original research (no abstracts, case-reports, reviews, meta-analysis, letters, or editorials).
RESULTS
Six articles were found eligible after screening the title, abstract and - when necessary - the full text for in- and exclusion criteria. All selected studies were case-control studies. Overall, results regarding the presence of CS were divergent. While the majority of patients with chronic traumatic neck pain (i.e. whiplash) are characterized by CS, this is not the case for patients with chronic idiopathic neck pain. The available evidence suggests that CS is not a major feature of chronic idiopathic neck pain. Individual cases might have CS pain, but further work should reveal how they can be characterized.
LIMITATIONS
Very few studies available.
CONCLUSIONS
Literature about CS in patients with chronic idiopathic non-traumatic neck pain is rare and results from the available studies provide an inconclusive message. CS is not a characteristic feature of chronic idiopathic and non-traumatic neck pain, but can be present in some individuals of the population. In the future a subgroup with CS might be defined, but based on current knowledge it is not possible to characterize this subgroup. Such information is important in order to provide targeted treatment.
Topics: Adult; Central Nervous System Sensitization; Chronic Disease; Chronic Pain; Female; Humans; Male; Middle Aged; Neck Pain; Whiplash Injuries
PubMed: 26000666
DOI: No ID Found -
Respiratory Care Dec 2015Cardiovascular autonomic neuropathy is one of the factors implicated in the high morbidity and mortality rate in patients with COPD. Thus, several studies and... (Review)
Review
Cardiovascular autonomic neuropathy is one of the factors implicated in the high morbidity and mortality rate in patients with COPD. Thus, several studies and nonsystematic reviews have increasingly reported autonomic function impairment in these subjects. For a better understanding, this systematic review was performed to evaluate not only the evidence for autonomic function impairment, but also factors influencing it. The results of the studies reviewed showed a strong level of evidence to support the impairment of heart rate variability in the time domain. A similar evidence level was also found to support impairment in baroreceptor sensitivity and muscle sympathetic nerve activity. Furthermore, this review identified physical activity level, muscle function, and circadian rhythm as the major influencing factors (strong evidence) of autonomic function in subjects with COPD. However, no definite conclusion could be reached for factors such as dyspnea, anxiety, body composition, pulmonary function, age, breathing frequency, ventilatory effort, quality of life, and disease severity due to limited, conflicting, or lack of existing evidence. The results of this review highlight relevant clinical messages for clinicians and other health-care providers regarding the role autonomic function can play as an important physiological marker for prognostication and stratification. Hence, autonomic function outcomes should be identified and considered during management of patients with COPD. Moreover, this review can serve as basis for future research aimed at assessing the interventions for autonomic function abnormalities in these patients.
Topics: Autonomic Nervous System; Autonomic Nervous System Diseases; Circadian Rhythm; Heart Rate; Humans; Motor Activity; Muscles; Pressoreceptors; Pulmonary Disease, Chronic Obstructive
PubMed: 26487747
DOI: 10.4187/respcare.04174