634 research outputs found

    Note on Moufang-Noether currents

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    The derivative Noether currents generated by continuous Moufang tranformations are constructed and their equal-time commutators are found. The corresponding charge algebra turns out to be a birepresentation of the tangent Mal'ltsev algebra of an analytic Moufang loop.Comment: LaTeX2e, 6 pages, no figures, presented on "The XVth International Colloquium on Integrable Systems and Quantum Symmetries, Prague, 15-17 June, 2006

    Establishing the tolerability and performance of tamarind seed polysaccharide (TSP) in treating dry eye syndrome: results of a clinical study

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    BACKGROUND: One of the problems arising from available preparations for dry eye syndrome is the limited residence time of products on the ocular surface. In this paper, we look at an innovative new treatment for dry eye, tamarind seed polysaccharide (TSP). TSP possesses mucomimetic, mucoadhesive and pseudoplastic properties. The 'mucin-like' molecular structure of TSP is similar to corneal and conjunctival mucin 1 (MUC1), a transmembrane glycoprotein thought to play an essential role in protecting and wetting the corneal surface and may explain its increased retention on the eye surface. METHODS: The activity of TSP and hyaluronic acid (HA) in the treatment of dry eye syndrome was compared in an open-label, randomised, single-centre clinical study. Thirty patients were randomised to receive three or more applications per day of either TSP 0.5%, TSP 1% or HA 0.2% (Hyalistil™) over a period of 90 days. The primary objective of tolerability was assessed by visual analogue scale (VAS), scoring of specific symptoms and the incidence of adverse events. Secondary objectives included improvement in stability of the precorneal tear film, subjective symptoms and corneal and conjunctival staining. RESULTS: TSP 0.5% and 1% were comparable to HA 0.2% with regard to both primary and secondary objective parameters. TSP 1% showed benefits over HA 0.2% for the subjective symptoms; trouble blinking, ocular burning and foreign body sensation. CONCLUSION: This study suggests that TSP 0.5% and 1% offer at least equivalent relief to HA 0.2% for dry eye syndrome. All treatments demonstrated optimal tolerability and are suitable for frequent use in the therapy of dry eye. TSP 1% produced promising results in terms of improvements in certain patient symptoms and suggests benefits of the TSP formulation. This study paves the way for a larger study to further establish the performance and safety of TSP compared with HA and highlights the need to expand this therapeutic agent to a wider dry eye population

    Circadian Organization in Hemimetabolous Insects

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    The circadian system of hemimetabolous insects is reviewed in respect to the locus of the circadian clock and multioscillatory organization. Because of relatively easy access to the nervous system, the neuronal organization of the clock system in hemimetabolous insects has been studied, yielding identification of the compound eye as the major photoreceptor for entrainment and the optic lobe for the circadian clock locus. The clock site within the optic lobe is inconsistent among reported species; in cockroaches the lobula was previously thought to be a most likely clock locus but accessory medulla is recently stressed to be a clock center, while more distal part of the optic lobe including the lamina and the outer medulla area for the cricket. Identification of the clock cells needs further critical studies. Although each optic lobe clock seems functionally identical, in respect to photic entrainment and generation of the rhythm, the bilaterally paired clocks form a functional unit. They interact to produce a stable time structure within individual insects by exchanging photic and temporal information through neural pathways, in which serotonin and pigment-dispersing factor (PDF) are involved as chemical messengers. The mutual interaction also plays an important role in seasonal adaptation of the rhythm

    Reduced intraepithelial corneal nerve density and sensitivity accompany desiccating stress and aging in C57BL/6 mice

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    Dry Eye disease causes discomfort and pain in millions of patients. Using a mouse acute desiccating stress (DS) model we show that DS induces a reduction in intraepithelial corneal nerve (ICN) density, corneal sensitivity, and apical extension of the intraepithelial nerve terminals (INTs) that branch from the subbasal nerves (SBNs). Topical application of 0.02% Mitomycin C (MMC) or vehicle alone has no impact on the overall loss of axon density due to acute DS. Chronic dry eye, which develops progressively as C57BL/6 mice age, is accompanied by significant loss of the ICNs and corneal sensitivity between 2 and 24 months of age. QPCR studies show that mRNAs for several proteins that regulate axon growth and extension are reduced in corneal epithelial cells by 24 months of age but those that regulate phagocytosis and autophagy are not altered. Taken together, these data demonstrate that dry eye disease is accompanied by alterations in intraepithelial sensory nerve morphology and function and by reduced expression in corneal epithelial cells of mRNAs encoding genes mediating axon extension. Précis: Acute and chronic mouse models of dry eye disease are used to evaluate the pathologic effects of dry eye on the intraepithelial corneal nerves (ICNs) and corneal epithelial cells. Data show reduced numbers of sensory nerves and alterations in nerve morphology, sensitivity, corneal epithelial cell proliferation, and expression of mRNAs for proteins mediating axon extension accompany the pathology induced by dry eye

    IL-17 producing lymphocytes cause dry eye and corneal disease with aging in RXRα mutant mouse

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    PURPOSE: To investigate IL-17 related mechanisms for developing dry eye disease in the Pinkie mouse strain with a loss of function RXRα mutation. METHODS: Measures of dry eye disease were assessed in the cornea and conjunctiva. Expression profiling was performed by single-cell RNA sequencing (scRNA-seq) to compare gene expression in conjunctival immune cells. Conjunctival immune cells were immunophenotyped by flow cytometry and confocal microscopy. The activity of RXRα ligand 9-cis retinoic acid (RA) was evaluated in cultured monocytes and γδ T cells. RESULTS: Compared to wild type (WT) C57BL/6, Pinkie has increased signs of dry eye disease, including decreased tear volume, corneal barrier disruption, corneal/conjunctival cornification and goblet cell loss, and corneal vascularization, opacification, and ulceration with aging. ScRNA-seq of conjunctival immune cells identified γδ T cells as the predominant IL-17 expressing population in both strains and there is a 4-fold increased percentage of γδ T cells in Pinkie. Compared to WT, IL-17a, and IL-17f significantly increased in Pinkie with conventional T cells and γδ T cells as the major producers. Flow cytometry revealed an increased number of IL-17 CONCLUSION: These findings indicate that RXRα suppresses generation of dry eye disease-inducing IL-17 producing lymphocytes s in the conjunctiva and identifies RXRα as a potential therapeutic target in dry eye

    Patterned expression of neurotrophic factors and receptors in human limbal and corneal regions

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    PURPOSE: To evaluate the expression patterns of neurotrophic factors (NTFs) and their receptors in the human cornea with the intention of exploring the role of NTFs in maintaining corneal epithelial stem cells in the limbus. METHODS: Fresh human corneoscleral tissues were prepared for frozen sections. Immunofluorescent staining was performed with primary antibodies against six members of three NTF families and their six receptors. To confirm the specificity of NTF primary antibodies, neutralization experiments with their corresponding peptides and western blot analysis were performed. RESULTS: Based on spatial and differential immuno-localization, three patterns of NTF expression were potentially involved in epithelial-mesenchymal interaction on the ocular surface: (1) the epithelial type: nerve growth factor (NGF) and glial cell-derived neurotrophic factor (GDNF); (2) the paracrine type: neurotrophin (NT)-3 and NT-4/5; and (3) the reciprocal type: brain-derived neurotrophic factor (BDNF). The stem cell-enriched basal cells of the limbal epithelium expressed three unique staining patterns for NTFs: (1) exclusively positive for NGF, GDNF, and their corresponding receptors, TrkA and GDNF family receptor alpha (GFR)-1; (2) relatively high levels of BDNF; and (3) negative for NT-3 and NT-4. Additionally, the neurotrophin common low-affinity receptor, p75NTR, was mainly expressed by the basal layer of the entire corneal and limbal epithelia, and TrkB and TrkC were evenly expressed by the entire corneal and limbal epithelia. BDNF, p75NTR, TrkB, and TrkC are also abundantly expressed by limbal stroma cells. No specific immunoreactivity to ciliary neurotrophic factor (CNTF) and its receptor, CNTFR, was detected in cornea tissue in situ. CONCLUSIONS: Our findings revealed patterned expression of NTFs and their receptors in the human ocular surface, suggesting that they may play a vital role in maintaining corneal epithelial stem cells in the limbus. NGF, GDNF, GFR-1, TrkA, and BDNF may serve as new limbal basal cell markers defining the corneal epithelial stem cell phenotype.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000250807800002&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Biochemistry & Molecular BiologyOphthalmologySCI(E)42ARTICLE217-191934-19411

    Expert consensus on the identification, diagnosis, and treatment of neurotrophic keratopathy

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    BACKGROUND: Neurotrophic keratopathy (NK) is a relatively uncommon, underdiagnosed degenerative corneal disease that is caused by damage to the ophthalmic branch of the trigeminal nerve by conditions such as herpes simplex or zoster keratitis, intracranial space-occupying lesions, diabetes, or neurosurgical procedures. Over time, epithelial breakdown, corneal ulceration, corneal melting (thinning), perforation, and loss of vision may occur. The best opportunity to reverse ocular surface damage is in the earliest stage of NK. However, patients typically experience few symptoms and diagnosis is often delayed. Increased awareness of the causes of NK, consensus on when and how to screen for NK, and recommendations for how to treat NK are needed. METHODS: An 11-member expert panel used a validated methodology (a RAND/UCLA modified Delphi panel) to develop consensus on when to screen for and how best to diagnose and treat NK. Clinicians reviewed literature on the diagnosis and management of NK then rated a detailed set of 735 scenarios. In 646 scenarios, panelists rated whether a test of corneal sensitivity was warranted; in 20 scenarios, they considered the adequacy of specific tests and examinations to diagnose and stage NK; and in 69 scenarios, they rated the appropriateness of treatments for NK. Panelist ratings were used to develop clinical recommendations. RESULTS: There was agreement on 94% of scenarios. Based on this consensus, we present distinct circumstances when we strongly recommend or may consider a test for corneal sensitivity. We also present recommendations on the diagnostic tests to be performed in patients in whom NK is suspected and treatment options for NK. CONCLUSIONS: These expert recommendations should be validated with clinical data. The recommendations represent the consensus of experts, are informed by published literature and experience, and may improve outcomes by helping improve diagnosis and treatment of patients with NK

    Smooth Loops and Fiber Bundles: Theory of Principal Q-bundles

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    A nonassociative generalization of the principal fiber bundles with a smooth loop mapping on the fiber is presented. Our approach allows us to construct a new kind of gauge theories that involve higher ''nonassociative'' symmetries.Comment: 20 page
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