Gravity complexes as a focus of seafloor fluid seepage: the Rio Grande Cone, SE Brazil.

Seafloor methane emissions can affect Earth's climate and ocean chemistry. Vast quantities of methane formed by microbial decomposition of organic matter are locked within gas hydrate and free gas on continental slopes, particularly in large areas with high sediment accumulations such as deep-sea fans. The release of methane in slope environments has frequently been associated with dissociation of gas hydrates near the edge of the gas hydrate stability zone on the upper slope, with discharges in greater water depths less understood. Here we show, using data from the Rio Grande Cone (western South Atlantic), that the intrinsic, gravity-induced downslope collapse of thick slope sediment accumulations creates structures that serve as pathways for gas migration, unlocking methane and causing seafloor emissions via giant gas flares in the water column. The observed emissions in the study region (up to 310 Mg year-1) are three times greater than estimates for the entire US North Atlantic margin and reveal the importance of collapsing sediment accumulations for ocean carbon cycling. Similar outgassing systems on the Amazon and Niger fans suggest that gravity tectonics on passive margins is a common yet overlooked mechanism driving massive seafloor methane emissions in sediment-laden continental slopes.

[Toward a better understanding of fatigue in schizophrenia]. / Vers une meilleure compréhension de la fatigue dans la schizophrénie.

Despite being one of the most common complaints of people with schizophrenia, fatigue remains largely unexplored in this population. The lack of knowledge regarding this complex symptom makes it often underdiagnosed and undertreated in schizophrenia. The aim of this brief perspective review is to outline the potential origins (distinguishing primary and secondary fatigue) and consequences of fatigue and to explore some potential treatments in this population. The current literature in schizophrenia has mainly investigated fatigue as a trait, using a self-administered questionnaire. Beyond this observational approach, which does not allow to capture the symptom in real life situations where high levels of fatigue can emerge rapidly, we propose to consider the state level of fatigue, for instance occurring after a prolonged period of cognitive activity (i.e. mental fatigue). We elaborate on the potential relationships between mental fatigue and negative symptoms of schizophrenia and propose some research avenues to test the effects of acute fatigue on effort intentions and behaviours. The consideration of the multidimensional aspects of fatigue will allow to move beyond the sole pharmacological approach to treat fatigue in schizophrenia. Targeting the cognitive as well as the performance components of fatigue through interventions such as concomitant aerobic exercise - mental training offers attractive prospects to reduce fatigue in this population and minimize its functional negative impact.

[Making innovation in teaching measurable : Psychometric validation of the "Radio-Prak": a questionnaire using the example of a clinical practical seminar in interventional radiology]. / Innovationen in der Lehre messbar machen : Psychometrische Validierung des Messinstrumentes "Radio-Prak" am Beispiel eines klinisch-praktischen Seminars der interventionellen Radiologie.

BACKGROUND: As part of the reform of medical education with a stronger focus on clinical-practical skills, a restructured seminar on interventional radiology was evaluated using a newly developed questionnaire. OBJECTIVES: Because knowledge in medical education is increasingly transferred by means of application-based teaching formats, a suitable evaluation tool is essential to assess the quality of newly implemented teaching courses. The aim of this study was to evaluate the seminar on interventional radiology and to validate the "Radio-Prak" questionnaire psychometrically in the process. MATERIALS AND METHODS: In the summer semester of 2018, 123 students participating in the newly established seminar were asked to document their satisfaction using the "Radio-Prak" questionnaire with 23 items employing a 5-point Likert scale. We evaluated the questionnaire psychometrically by performing exploratory factor (EFA) and reliability analysis and examined differential validity by group differences. RESULTS: The newly structured seminar on interventional radiology was met with great approval by students (mean global rating = 1.31, on a grading scale where 1 = very good, 5 = insufficient). EFA revealed that the questionnaire consisted of two main factors "didactic quality" and "practical quality" (five items each, α = 0.68). The seminar was rated more positively when students perceived the time for practice as sufficient (p < 0.05). Furthermore, female students demonstrated significantly less self-esteem, identified by the item "I have improved my spatial ability through the seminar," (p < 0.05). CONCLUSION: The "Radio-Prak" questionnaire is both reliable and valid as an instrument to evaluate the quality of a clinical-practical seminar. The students assessed the didactic dimension, but also rated the practical component as important in the assessment.

[Intraoperative Optical Coherence Tomography - an Overview of Current Clinical Data for the Application in the Anterior and Posterior Segments]. / Intraoperative optische Kohärenztomografie ­ eine aktuelle Übersicht klinischer Studien zur Anwendung im Vorder- und Hinterabschnitt.

Intraoperative optical coherence tomography (iOCT) represents another milestone in ocular imaging technologies. Now, for the first time, high resolution OCT images are available not only pre- or postoperatively, but also intraoperatively. In recent years, there have been significant advances in iOCT technology - from hand-held probes and mounted systems towards iOCT systems which are fully integrated into the surgical microscope and which provide seamless integration into the workflow. These systems offer high-resolution, intraoperative OCT scans in real-time and provide additional information on microstructures of the retina or the cornea. These findings may even lead to a modification of surgical strategies. Like any other new technology, iOCT technology still has some limitations, such as shadowing from instruments and the lack of eye tracking systems. Therefore, the current state of iOCT technology still requires some skill to track surgical maneuvers in real time. Further research and development will help to solve these limitations in the future. However, even if not required for all surgical procedures, iOCT imaging can already improve safety and control in many surgical procedures on the anterior and posterior segments. This has already been shown in several studies and case series. Particularly in the surgery of vitreomacular traction, peeling of epiretinal membranes (ERM peeling) and macular hole surgery, iOCT offers significant added value. It improves the visualisation of transparent structures and helps to avoid the usage of dyes. In addition the success of the surgical maneuvers can be investigated intraoperatively. In lamellar keratoplasty and glaucoma surgery too, iOCT improves precision and safety. Moreover, iOCT technology may help to achieve further insight into ocular pathologies and a better understanding of the impact of surgical maneuvers on visual rehabilitation. Further prospective studies are however required to evaluate the usefulness of iOCT in various surgical procedures on both, the anterior and posterior segments.

Glypican-2 levels in cerebrospinal fluid predict the status of adult hippocampal neurogenesis.

Adult hippocampal neurogenesis is a remarkable form of brain plasticity through which new neurons are generated throughout life. Despite its important roles in cognition and emotion and its modulation in various preclinical disease models, the functional importance of adult hippocampal neurogenesis in human health has not been revealed because of a lack of tools for monitoring adult neurogenesis in vivo. Therefore, we performed an unbiased proteomics screen to identify novel proteins expressed during neuronal differentiation using a human neural stem cell model, and we identified the proteoglycan Glypican-2 (Gpc2) as a putative secreted marker of immature neurons. Exogenous Gpc2 binds to FGF2 and inhibits FGF2-induced neural progenitor cell proliferation. Gpc2 is enriched in neurogenic regions of the adult brain. Its expression is increased by physiological stimuli that increase hippocampal neurogenesis and decreased in transgenic models in which neurogenesis is selectively ablated. Changes in neurogenesis also result in changes in Gpc2 protein level in cerebrospinal fluid (CSF). Gpc2 is detectable in adult human CSF, and first pilot experiments with a longitudinal cohort indicate a decrease over time. Thus, Gpc2 may serve as a potential marker to monitor adult neurogenesis in both animal and human physiology and disease, warranting future studies.

Efficacy of 0.2 µg/day fluocinolone acetonide implant (ILUVIEN) in eyes with diabetic macular edema and prior vitrectomy.

PurposeLimited data are available on the efficacy of the 0.2 µg/day fluocinolone acetonide (FAc) implant in eyes with prior vitrectomy. Here, we present a collection of 26 vitrectomized eyes treated with the 0.2 µg/day FAc implant.MethodsRetrospective study involving six centers from four European countries analyzing the safety and efficacy data from patients (26 eyes from 25 patients) with DME and a prior vitrectomy that had been treated with one 0.2 µg/day FAc implant.ResultsPrior intravitreal therapies included anti-VEGF (mean, 3.8 injections) and steroids (mean, 1.9 injections). Pars plana vitrectomy (PPV) was performed in these eyes primarily for abnormalities of vitreoretinal interface, followed by proliferative diabetic retinopathy and vitreous hemorrhage. The 0.2 µg/day FAc implant was injected 24.2 months, on average, after PPV and the mean duration of follow-up after injection was 255 days (range, 90 to 759 days). The mean change in BCVA was +11.7 ETDRS letters (range, -19 to +40 letters; P<0.0004) and the mean change in central foveal thickness (CFT) was -233.5 µm (range, -678 to 274 µm; P<0.0001). The mean change in IOP from baseline at the last visit was +1.4 mm Hg (range, -9 to +8 mm Hg; P=0.0090). Eight eyes initiated or continued IOP lowering medications.ConclusionsThese data suggest the 0.2 µg/day FAc implant is effective in vitrectomized patients with an acceptable safety profile. Further studies are still required to confirm the current findings and to assess the effect of the 0.2 µg/day FAc implant over a longer period of follow-up.

Nonspecific positivity on the Luminex crossmatch assay for anti-human leukocyte antigen antibodies due to antibodies directed against the antibody coated beads.

Two cases are described of previously unreported false positivity on the Luminex crossmatch assay due to non HLA specific antibodies directed against the beads. In both cases the Luminex crossmatch indicated the presence of donor specific antibodies to class II HLA antigens, which was not substantiated by the clinical scenario or other assays. We could demonstrate the non specificity of these antibodies through using the same assay in a modified form where beads were unexposed to cell lysate and therefore did not carry HLA antigens at all. These cases further serve to emphasize the absolute necessity of correlating positive results with the priming history, and confirming their relevance using other platforms.

[Placenta Growth Factor (PlGF) and Retinal Vascular Diseases--Current Knowledge from Experimental and Clinical Studies]. / Plazenta-Wachstumsfaktor (PlGF) und retinale Gefäßerkrankungen--experimentelle und klinische Datenlage.

Pathological angiogenesis is a major characteristic of many diseases, such as cancer and retinal vascular disorders. Vascular diseases of the eye, such as diabetic retinopathy (DR) and neo-vascular age-related macular degeneration (nAMD), are the main cause of severe vision loss. The specific role of the cytokine VEGF-A in these pathologies has been proven in many ways. Thus, VEGF-A is still the major target for antiangiogenic therapy. Recently, another angiogenic factor, the placental growth factor (PlGF), has become a focal point for clinical research. This interest is based on the fact that the expression of PlGF is limited to embryonic development and PlGF can hardly be found in healthy tissues. During pathological angiogenetic processes, such as retinal vascular diseases, however, PlGF is increasingly expressed. Substances which inhibit the effect of PlGF and thus pathological angiogenesis, without simultaneously affecting healthy tissues, could significantly extend the therapeutic options for the treatment of retinal vascular diseases. Convincing results have recently been published from clinical trials in oncology, as well as preclinical investigations in animal models of retinal vascular diseases. The aim of this review is to summarise the role of PlGF in retinal vascular diseases and the available experimental data on the therapeutic potential of PlGF inhibitors.

[Seronegative antiphospholipid syndrome, catastrophic syndrome, new anticoagulants: learning from a difficult case report]. / Syndrome des antiphospholides "séronégatif ", syndrome catastrophique, nouveaux anticoagulants: enseignements d'une observation de prise en charge difficile.

INTRODUCTION: The diagnosis of the antiphospholipid syndrome (APS) is based on clinical and biological criteria including the persistent presence of antiphospholipid antibodies and thrombotic events or pregnancy morbidity. Heparins relayed by vitamin K antagonists (VKA) are the gold standard treatment for thrombosis. CASE REPORT: We report a 17-year-old man who presented with an initially seronegative antiphospholipid syndrome, in whom the diagnosis was late, only obtained after anticoagulation withdrawing, when a catastrophic antiphospholipid syndrome (CAPS) with cutaneous lesions and disseminated intravascular coagulation syndrome occurred. For personal convenience, this patient was initially treated with fondaparinux followed by a new oral anticoagulant (rivaroxaban) before to return to the conventional VKA treatment. CONCLUSION: The "seronegative" APS is a controversial concept reflecting the heterogeneity of antigenic targets for aPL. This diagnosis may be considered after a rigorous work-up, with the help of haemostasis laboratories testing new emerging aPL assays. In APS, the new anticoagulants represent an attractive option needing nevertheless prospective studies to evaluate their safety and efficacy. Lupus anticoagulant detection in patients treated by new oral anticoagulants is not easy by usually recommended coagulation tests.

[Reliable UV-light protection in intraocular lenses--scientific rationale and quality requirements]. / Zuverlässiger UV-Schutz durch Intraokularlinsen--Rationale und Qualitätsanforderungen.

Since the late 1980s implantation of UV-blocker intraocular lenses during cataract surgery has become an internationally accepted standard. Last year the Kassenärztliche Vereinigung Bayern (KVB) and statutory health insurance organisations proposed for the first time quality criteria for intraocular lenses (IOL), thereby including exact parameters for the amount of UV light transmission (≤10% at 400 nm). Since then, the discussion has been raised again as to what extent IOLs should filter or block UV light. In this article, exact definitions of spectral subbands within the optical radiation band are given. Today, 400 nm is the internationally accepted standard to distinguish UV light and visible light. Moreover, exposure of the eye to UV radiation is described as well as mechanisms of photooxidative damage to the retina. Comprehensive laboratory and animal experimental studies show that light of short wave lengths, i.e., above all UV light but also blue light, may induce photochemical damage to the retina. Primary sites of such damage are both the outer segments of the photoreceptors and the retinal pigment epithelium (RPE). Physiological protective mechanisms of the eye, such as filtering properties of different ocular media are described in detail. Cornea, aqueous and vitreous absorb UV radiation below 300 nm, while the natural adult lens absorbs UV radiation between 300 and 400 nm. This protection is lost when the lens is removed by cataract surgery and thus should be restored. UV light does not contribute to vision but damages retinal structures. Therefore, UV-blocking intraocular lenses with a 10% cut-off near 400 nm should be implanted during cataract surgery. This ensures sufficient retinal protection after surgery. These theoretical considerations are supported by results from animal and clinical studies.

Chemical composition and insecticidal activity of essential oils of two aromatic plants from Ivory Coast against Bemisia tabaci G. (Hemiptera: Aleyrodidae).

Essential oils of aromatic plants with insecticidal properties are nowadays considered as alternative insecticides to protect cultures from attack by insect pest. The aims of the present work were to evaluate the toxicity of the essential oils vapors of two aromatic plants (Lippia multiflora Mold. and Aframomum latifolium K. Schum) against Bemisia tabaci and to characterize their chemical composition. The highest fumigant toxicity against B. tabaci adults was observed with the L. multiflora oil: by exposure to 0.4 microL/L air, the lethal time inducing 90% mortality (LT90) was below 2 hours for this essential oil whereas it reached 15 h in the case of the A. latifolium oil. Both oils were analyzed by GC-FID and GC-MS on two capillary columns. The oil of L. multiflora contained a majority of oxygenated terpenoids mainly represented by the two acyclic components linalool (46.6%) and (E)-nerolidol (16.5%); the oil of A. latifolium was dominated by hydrocarbonated terpenoids among them beta-pinene (51.6%) and beta-caryophyllene (12.3%) were the two major components.

[Blue Light-Filtering IOLs - Currently available data]. / Blaufilter-Intraokularlinsen - derzeitige Datenlage.

Data from both experimental and epidemiological trials have suggested a potential correlation between extraction of the natural lens associated with exposure to photo-oxidative stress to the retina and a progression of diseases such as AMD. A fundamental factor could be the unchecked exposure to blue light. This is why in the past years so-called blue light-filtering intraocular lenses have been implanted to serve as a protection to the retina. The following contribution is based on a data base research (Pub Med, National Library of Medicine, USA) and summarises information currently available on the use of blue light-filtering lenses. Experimental modeling has shown that, compared to regular UV lenses, blue light-filtering lenses block a considerable part of blue light transmission to the retina and reduce damage to retinal cells and production of inflammatory markers such as VEGF. The majority of the clinical data demonstrate that blue light-filtering lenses are compatible in terms of visual acuity, contrast sensitivity and colour perception as well as patient-rated quality of vision. But a few additional studies report reduced contrast sensitivity and limitations in mesopic vision.This is also true for the circadian rhythm. However, the evaluation of this parameter in connection with blue light-filtering lenses has only been done on a theoretical basis. Long-term data showing that blue light-filtering lenses actually do reduce the incidence of retinal diseases such as AMD are currently not available.

Antivascular endothelial growth factor as an approach for macular edema.

Macular edema is an abnormal thickening of the macula associated with the accumulation of excess fluid in the extracellular space of the neurosensory retina. The following chapter looks at the basic pathomechanisms of macular edema as well as major pathologic conditions leading to it: special focus is on diabetic retinopathy, retinal venous occlusions and a number of inflammatory disorders. Currently available data on up-to-date pharmacologic treatment options such as steroids and anti-VEGF compounds is presented and discussed.

[Oxidative tissue damage]. / Was ist oxidativer Stress?

Oxidative stress is defined as an overflow of oxidative metabolites either in the human body or in a compartment of the body. Today this chemical definition has been slightly modified and encompasses an elevation of oxidative metabolites or a relative deficiency of anti-oxidants. Molecular oxygen is the basis of many highly reactive oxidative species which are able to directly damage or lead to the generation of secondary reactions which then initiate oxidative processes. The cell has established numerous mechanisms and strategies to antagonise those oxidative processes at different steps. Many diseases have been shown to be either related to or even be initiated by oxidative processes. The eye is at high risk to be damaged by oxidative mechanisms. One major reason is its permanent exposition to oxidative stimuli. The biochemical composition of ocular structures, especially that of the retina (unsaturated fatty acids), is an important factor making the eye more susceptible as compared to other organs. Ocular ischaemia, ischaemia or hypoxia of the retina, diabetic retinopathy and glaucoma are important disease entities that are initiated or propagated by oxidative processes. Ischaemic processes lead to classical reactions of the oxidative pathway. This is no longer believed to be the case in diabetic retinopathy. Here, advanced glycation end products (AGE's) and related species are able to induce oxidative reactions and the expression of growth factors. In age-related macular degeneration, photodynamic processes that already occur in childhood are believed to be a major factor contributing to the pathogenesis of the disease process. In addition, the expression of growth factors and new vessel growth can be initiated via inflammatory reactions or oxidative metabolites.

[Is there a drug therapy for age-related macular degeneration?--current status and new therapeutic approaches]. / Gibt es eine medikamentöse Therapie der altersbedingten Makuladegeneration?--Derzeitiger Stand und neue therapeutische Ansätze.

Age-related macular degeneration (AMD) is the major cause of legal blindness in society today. In dry AMD age-related changes in Bruch's membrane and RPE result in the accumulation of cell debris with consequent degeneration. In the less common but more aggressive form, wet AMD, hypoxia and inflammation lead to an up-regulation of different growth factors such as VEGF resulting in formation of choroidal neovascularisation. Different therapeutic modalities have evolved to address this problem. Examples are photodynamic therapy to eradicate choroidal neovascularisation (CNV) via a physiochemical reaction or intravitreal application of anti-VEGF agents to stop leakage of fluid from the same CNV. The overall results have been either disappointing or not practical because of the necessity of chronic treatment. The treatment goal continues to evolve to that already realised in oncology which is for a cure. This mandates the investigation of combination strategies. Combination strategies should focus on utilising the differing mechanisms of action on the pathogenesis of the disease all the while minimising the side effects of the individual therapeutic agents.

Equilibrium sorption isotherm studies of Cd(II), Pb(II) and Zn(II) ions detoxification from waste water using unmodified and EDTA-modified maize husk

The mobilization of heavy metals in the environment due to industrial activities is of serious concern due to the toxicity of these metals in humans and other forms of life. The equilibrium adsorption isotherms of Cd(II), Pb(II) and Zn(II) ions, detoxification from waste water using unmodified and EDTA-modified maize husk have been studied. Maize husk was found to be an excellent adsorbent for the removal of these metal ions. The amount of these metal ions adsorbed increased as the initial concentration increased. Also, EDTA-modification enhanced the adsorption capacity of maize husk due to the chelating ability of ethylenediamine tetra acetic acid (EDTA). Among the three adsorption isotherms tested, Dubinin-Radushkevich isotherm gave the best fit with R² value ranging from 0.7646 to 0.9988 and an average value of 0.9321. This is followed by Freundlich and then Langmiur isotherms. The sorption process was found to be mostly a physiosorption process as seen from the apparent energy of adsorption which ranged from 1.03 KJ/mol to 12.91 KJ/mol. Therefore, this study demonstrates that maize husk which is an environmental pollutant could be used to adsorb heavy metals and achieve environmental cleanliness.

[Scope and limititions of innovative vitrectomy systems]. / Möglichkeiten und Grenzen der innovativen Vitrektomiesysteme.

PURPOSE: The aim of the present article is to review the methodical and technological development of pars plana vitrectomy. Special attention is drawn to safety, efficiency and functionality of the innovative 25-gauge und 23-gauge vitrectomy systems which are compared to the standard 20-gauge vitrectomy system. This was done based on clinical studies and case reports. METHODS: A literature search was conducted in a cluster of different medical databases (XMedall; XPharmall). Focus of the research was the "development" and "status quo" of pars plana vitrectomy. In particular, clinical studies and case reports dealing with safety and efficiency of 20-, 23- and 25-gauge vitrectomy systems have been evaluated. Only peer-reviewed articles from 1966 until today were investigated. Finally, a descriptive analysis of the relevant studies was made. RESULTS: Both innovative vitrectomy systems are safe and effective and help to reduce operating time. There was no significant difference in postoperative complications following 25-gauge vitrectomy and 20-gauge vitrectomy. 25-gauge instruments, however, show a greater flexibility. For this reason a certain learning curve is required and the range of application is limited. Due to its greater stiffness and larger diameter, the 23-gauge system - while still allowing a transconjunctival access - may overcome the disadvantages of the 25-gauge system. However, the use of silicone oil may lead to leakage of the sclerotomies and thus necessitate additional suturing. CONCLUSION: The use of both innovative vitrectomy systems offers the advantage of a faster and less invasive surgical procedure. However, there are disadvantages which limit the indications for 25-gauge vitrectomy. The 23-gauge vitrectomy may overcome these disadvantages and - due to its wider range of application - may be used instead of conventional 20-gauge vitrectomy in most cases. It may therefore become the new standard for vitrectomy.

Verteporfin therapy and triamcinolone acetonide: convergent modes of action for treatment of neovascular age-related macular degeneration.

PURPOSE: Choroidal neovascularization associated with age-related macular degeneration is the primary cause of blindness in the elderly in developed countries, due to a number of pathogenic effects, including angiogenesis, cell-mediated inflammation, leukocyte adhesion and extravasation, and matrix remodeling. METHODS: By producing photochemical effects at the site of target tissue (lesion), photodynamic therapy (PDT) can induce vascular damage and blood flow stasis, leading to occlusion of vascularization and lesion leakage. RESULTS: PDT with verteporfin (Visudyne, Novartis) has been shown to be safe and effective in reducing the risk of vision loss in patients with classic containing subfoveal CNV and occult with no classic CNV. However, in predominantly occult CNV, the treatment may be most effective in smaller lesions, and less in larger lesions. Most important, visual acuity rarely is improved. CONCLUSIONS: Pilot studies and large case series suggest that a combination of PDT and intravitreal triamcinolone acetonide has the potential to improve visual outcomes and reduce the need for additional treatments. Randomized, prospective clinical trials are underway to confirm the efficacy and safety of this novel treatment modality.