523 research outputs found

    Preface

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    Reliability of Intra-Retinal Layer Thickness Estimates

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    Purpose Measurement of intra-retinal layer thickness using optical coherence tomography (OCT) has become increasingly prominent in multiple sclerosis (MS) research. Nevertheless, the approaches used for determining the mean layer thicknesses vary greatly. Insufficient data exist on the reliability of different thickness estimates, which is crucial for their application in clinical studies. This study addresses this lack by evaluating the repeatability of different thickness estimates. Methods Studies that used intra-retinal layer segmentation of macular OCT scans in patients with MS were retrieved from PubMed. To investigate the repeatability of previously applied layer estimation approaches, we generated datasets of repeating measurements of 15 healthy subjects and 13 multiple sclerosis patients using two OCT devices (Cirrus HD-OCT and Spectralis SD-OCT). We calculated each thickness estimate in each repeated session and analyzed repeatability using intra-class correlation coefficients and coefficients of repeatability. Results We identified 27 articles, eleven of them used the Spectralis SD-OCT, nine Cirrus HD-OCT, two studies used both devices and two studies applied RTVue-100. Topcon OCT-1000, Stratus OCT and a research device were used in one study each. In the studies that used the Spectralis, ten different thickness estimates were identified, while thickness estimates of the Cirrus OCT were based on two different scan settings. In the simulation dataset, thickness estimates averaging larger areas showed an excellent repeatability for all retinal layers except the outer plexiform layer (OPL). Conclusions Given the good reliability, the thickness estimate of the 6mm-diameter area around the fovea should be favored when OCT is used in clinical research. Assessment of the OPL was weak in general and needs further investigation before OPL thickness can be used as a reliable parameter

    No signs of check-list fatigue - introducing the StOP? intra-operative briefing enhances the quality of an established pre-operative briefing in a pre-post intervention study.

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    The team timeout (TTO) is a safety checklist to be performed by the surgical team prior to incision. Exchange of critical information is, however, important not only before but also during an operation and members of surgical teams frequently feel insufficiently informed by the operating surgeon about the ongoing procedure. To improve the exchange of critical information during surgery, the StOP?-protocol was developed: At appropriate moments during the procedure, the leading surgeon briefly interrupts the operation and informs the team about the current Status (St) and next steps/objectives (O) of the operation, as well as possible Problems (P), and encourages questions of other team members (?). The StOP?-protocol draws attention to the team. Anticipating the occurrence of StOP?-protocols may support awareness of team processes and quality issues from the beginning and thus support other interventions such as the TTO; however, it also may signal an additional demand and contribute to a phenomenon akin to "checklist fatigue." We investigated if, and how, the introduction of the StOP?-protocol influenced TTO quality. This was a prospective intervention study employing a pre-post design. In the visceral surgical departments of two university hospitals and one urban hospital the quality of 356 timeouts (out of 371 included operation) was assessed by external observers before (154) and after (202) the introduction of the StOP?-briefing. Timeout quality was rated in terms of timeout completeness (number of checklist items mentioned) and timeout quality (engagement, pace, social atmosphere, noise). As compared to the baseline, after the implementation of the StOP?-protocol, observed timeouts had higher completeness ratings (F = 8.69, p = 0.003) and were rated by observers as higher in engagement (F = 13.48, p < 0.001), less rushed (F = 14.85, p < 0.001), in a better social atmosphere (F = 5.83, p < 0.016) and less noisy (F = 5.35, p < 0.022). Aspects of TTO are affected by the anticipation of StOP?-protocols. However, rather than harming the timeout goals by inducing "checklist fatigue," it increases completeness and quality of the team timeout

    Investigation of Visual System Involvement in Spinocerebellar Ataxia Type 14

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    Spinocerebellar ataxia type 14 (SCA-PRKCG, formerly SCA14) is a rare, slowly progressive disorder caused by conventional mutations in protein kinase Cγ (PKCγ). The disease usually manifests with ataxia, but previous reports suggested PRKCG variants in retinal pathology. To systematically investigate for the first time visual function and retinal morphology in patients with SCA-PRKCG. Seventeen patients with PRKCG variants and 17 healthy controls were prospectively recruited, of which 12 genetically confirmed SCA-PRKCG patients and 14 matched controls were analyzed. We enquired a structured history for visual symptoms. Vision-related quality of life was obtained with the National Eye Institute Visual Function Questionnaire (NEI-VFQ) including the Neuro-Ophthalmic Supplement (NOS). Participants underwent testing of visual acuity, contrast sensitivity, visual fields, and retinal morphology with optical coherence tomography (OCT). Measurements of the SCA-PRKCG group were analyzed for their association with clinical parameters (ataxia rating and disease duration). SCA-PRKCG patients rate their vision-related quality of life in NEI-VFQ significantly worse than controls. Furthermore, binocular visual acuity and contrast sensitivity were worse in SCA-PRKCG patients compared with controls. Despite this, none of the OCT measurements differed between groups. NEI-VFQ and NOS composite scores were related to ataxia severity. Additionally, we describe one patient with a genetic variant of uncertain significance in the catalytic domain of PKCγ who, unlike all confirmed SCA-PRKCG, presented with a clinically silent epitheliopathy. SCA-PRKCG patients had reduced binocular vision and vision-related quality of life. Since no structural retinal damage was found, the pathomechanism of these findings remains unclear

    Afferent Visual Pathway Affection in Patients with PMP22 Deletion-Related Hereditary Neuropathy with Liability to Pressure Palsies

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    Background The PMP22 gene encodes a protein integral to peripheral myelin. Its deletion leads to hereditary neuropathy with liability to pressure palsies (HNPP). PMP22 is not expressed in the adult central nervous system, but previous studies suggest a role in CNS myelin development. The objective of this study was to identify potential structural and functional alterations in the afferent visual system in HNPP patients. Methods Twenty HNPP patients and 18 matched healthy controls (HC) were recruited in a cross-sectional study. Participants underwent neurological examination including visual acuity, visual evoked potential (VEP) examination, optical coherence tomography (OCT), and magnetic resonance imaging with calculation of brain atrophy, regarding grey and white matter, and voxel based morphometry (VBM), in addition answered the National Eye Institute’s 39-item Visual Functioning Questionnaire (NEI- VFQ). Thirteen patients and 6 HC were additionally examined with magnetic resonance spectroscopy (MRS). Results All patients had normal visual acuity, but reported reduced peripheral vision in comparison to HC in the NEI-VFQ (p = 0.036). VEP latency was prolonged in patients (P100 = 103.7±5.7 ms) in comparison to healthy subjects (P100 = 99.7±4.2 ms, p = 0.007). In OCT, peripapillary retinal nerve fiber layer thickness RNFL was decreased in the nasal sector (90.0±15.5 vs. 101.8±16.5, p = 0.013), and lower nasal sector RNFL correlated with prolonged VEP latency (Rho = -0.405, p = 0.012). MRS revealed reduced tNAA (731.4±45.4 vs. 814.9±62.1, p = 0.017) and tCr (373.8±22.2 vs. 418.7±31.1, p = 0.002) in the visual cortex in patients vs. HC. Whole brain volume, grey and white matter volume, VBM and metabolites in a MRS sensory cortex control voxel did not differ significantly between patients and HC. Conclusion PMP22 deletion leads to functional, metabolic and macro- structural alterations in the afferent visual system of HNPP patients. Our data suggest a functional relevance of these changes for peripheral vision, which warrants further investigation and confirmation

    Modelling of climate-sensitive pests in plant health

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    Klimasensitive Schadorganismen sind Arten, deren Risiko einen Schaden zu verursachen sich aufgrund der vorhergesagten klimatischen Veränderungen voraussichtlich erheblich verändern wird. Damit stellen sie eine besondere Herausforderung für die Pflanzengesundheit dar. Zur Vorhersage des Etablierungs- und Ausbreitungspotenzials dieser Schadorganismen ist eine Bewertung unter verschiedenen Umwelt- und Managementszena­rien unerlässlich. Ein effizientes Werkzeug zur Unter­suchung des Risikos klimasensitiver Schadorganismen (SO) sind prozess-orientierte Simulationsmodelle. Im Rahmen des Projektes,,ProgRAMM“ wird ein solches Modell, das auf Grundlage artspezifischer physiologischer Parameter und Verbreitungseigenschaften arbeitet, entwickelt. Mit diesem Modell wird es möglich sein, die o.g. Vorhersagen und Szenarioanalysen zu realisieren und langfristig einen übertragbaren, verallgemeinerten Open-Source-Modellrahmen als Standardverfahren zur Unterstützung von pflanzengesundheitlichen Risikoanalysen klimasensitiver SO zu etablieren. Dabei steht beson­ders im Vordergrund, dass das Modell leicht erweiterbar ist und sich leicht mit einzelnen Wirtspflanzen, aktu­ellen Klimadatensätzen sowie neuen An-/Abwesenheitsdaten der SO koppeln lässt. Die Ergebnisse des Modells werden in Form von Verbreitungs- und Risikokarten grafisch dargestellt. Diese Karten dienen der verbesserten Abschätzung und Darstellung der wirtschaft­lichen und ökologischen Risiken durch die Schadorganismen in Risikoanalysen. Zusätzlich kann durch die Identifizierung von Hochrisikogebieten für die Ansiedlung von SO, die Planung von Monitoring-Aktivitäten unterstützt werden. Das Modell wird open-source gehalten und um verschiedene Untermodelle sowie artspezifische Funktionen und Parametrisierung erweiterbar sein, damit die Übertragbarkeit auf möglichst viele Schadorganismengruppen (Pilze, Insekten, Milben, Nematoden, Bakte­rien) sichergestellt ist.Climate-sensitive pests are those whose risk of causing damage is likely to change significantly due to predicted climatic changes. They therefore pose a particular challenge to plant health. In order to predict the establishment and spread potential of these pests, an assessment under various environmental and management scenarios is essential. Process-oriented simulation models are an efficient tool to investigate the occurrence and spread of climate-sensitive pests. In the project ‘ProgRAMM’ (Proactive phytosanitary risk analysis through modelling and monitoring: adaptation to long-term risks caused by climate-sensitive pests) such a model based on species-specific physiological parameters and distribution characteristics is being developed. With this model the above mentioned predictions and scenario analyses can be carried out. A transferable, generalized open-source modelling framework will be established as a standard procedure to support plant health risk analyses (PRA) of climate-sensitive pests. A particular focus is on the fact that the model is easily extensible and that it can be easily coupled with a different set of additional host plants, plant databases, different climate data sets as well as new presence/absence data of pests. The results of the model are presented graphically in the form of distribution and risk maps. The results can be used in PRAs to better assess the economic and ecological risks of a pest. In addition, the high-risk areas for the occurrence of pests will be identified to support the planning of efficient monitoring activities. The open source license along with the modular nature of the model components will ensure transferability to pest groups such as fungi, insects, mites, nematodes and bacteria. This will also enable the extension of the model by different sub-models as well as by species-specific functions and parameterization

    Estimativa dos Fluxos Superficiais de Energia e Massa na Região do Pampa Gaúcho

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    As trocas de energia e massa entre o pampa gaúcho e a atmosferasão estimadas através do modelo de superfície SiB2 e comparados comdados experimentais obtidos no sito experimental de Candiota-RS. Asestimativas dos fluxos superficiais descrevem satisfatoriamente a interaçãoentre a superfície e a atmosfer

    Spinocerebellar ataxia type 14: refining clinicogenetic diagnosis in a rare adult‐onset disorder

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    Objectives: Genetic variant classification is a challenge in rare adult-onset disorders as in SCA-PRKCG (prior spinocerebellar ataxia type 14) with mostly private conventional mutations and nonspecific phenotype. We here propose a refined approach for clinicogenetic diagnosis by including protein modeling and provide for confirmed SCA-PRKCG a comprehensive phenotype description from a German multi-center cohort, including standardized 3D MR imaging. Methods: This cross-sectional study prospectively obtained neurological, neuropsychological, and brain imaging data in 33 PRKCG variant carriers. Protein modeling was added as a classification criterion in variants of uncertain significance (VUS). Results: Our sample included 25 cases confirmed as SCA-PRKCG (14 variants, thereof seven novel variants) and eight carriers of variants assigned as VUS (four variants) or benign/likely benign (two variants). Phenotype in SCA-PRKCG included slowly progressive ataxia (onset at 4-50 years), preceded in some by early-onset nonprogressive symptoms. Ataxia was often combined with action myoclonus, dystonia, or mild cognitive-affective disturbance. Inspection of brain MRI revealed nonprogressive cerebellar atrophy. As a novel finding, a previously not described T2 hyperintense dentate nucleus was seen in all SCA-PRKCG cases but in none of the controls. Interpretation: In this largest cohort to date, SCA-PRKCG was characterized as a slowly progressive cerebellar syndrome with some clinical and imaging features suggestive of a developmental disorder. The observed non-ataxia movement disorders and cognitive-affective disturbance may well be attributed to cerebellar pathology. Protein modeling emerged as a valuable diagnostic tool for variant classification and the newly described T2 hyperintense dentate sign could serve as a supportive diagnostic marker of SCA-PRKCG
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