Uncertainty in Functional Network Representations of Brain Activity of Alcoholic Patients.

In spite of the large attention received by brain activity analyses through functional networks, the effects of uncertainty on such representations have mostly been neglected. We here elaborate the hypothesis that such uncertainty is not just a nuisance, but that on the contrary is condition-dependent. We test this hypothesis by analysing a large set of EEG brain recordings corresponding to control subjects and patients suffering from alcoholism, through the reconstruction of the corresponding Maximum Spanning Trees (MSTs), the assessment of their topological differences, and the comparison of two frequentist and Bayesian reconstruction approaches. A machine learning model demonstrates that the Bayesian reconstruction encodes more information than the frequentist one, and that such additional information is related to the uncertainty of the topological structures. We finally show how the Bayesian approach is more effective in the validation of generative models, over and above the frequentist one, by proposing and disproving two models based on additive noise.

Role of Ocular Ultrasonography to Distinguish Papilledema From Pseudopapilledema.

BACKGROUND: We prospectively evaluated the sensitivity and specificity of ocular ultrasonography (OUS) to distinguish papilledema from pseudopapilledema. METHODS: Forty-nine study participants, with optic disc elevation, underwent neuro-ophthalmic evaluation, OUS, fundus photography, and optical coherence tomography (OCT) of the optic nerve head at the initial and follow-up visits (≤6 months apart). Participants were classified as having papilledema if there was a change in optic nerve appearance on fundus photographs, as determined by a masked observer, between initial and follow-up visits ≤6 months apart. OUS was considered positive when the optic nerve sheath width was >3.3 mm and the 30° test was positive. Ocular ultrasonographic findings were correlated in patients who had papilledema vs patients who had pseudopapilledema. In a subanalysis, OUS findings were also correlated with change in peripapillary retinal nerve fiber layer thickness on OCT of the optic nerve head between initial and follow-up visits. RESULTS: OUS was 68% (17/25) sensitive for papilledema and 54% (13/24) specific for pseudopapilledema. When using OCT parameters to define papilledema, the sensitivity of OUS to diagnose papilledema decreased to 62%. Positive OUS correlated with elevated opening pressure on lumbar puncture and with signs of increased intracranial pressure on MRI. CONCLUSION: OUS alone was less sensitive in diagnosing papilledema than previously thought. Therefore, OUS may not be helpful in distinguishing between papilledema and pseudopapilledema.

Toward Accelerated Training of Parallel Support Vector Machines Based on Voronoi Diagrams.

Typical applications of wireless sensor networks (WSN), such as in Industry 4.0 and smart cities, involves acquiring and processing large amounts of data in federated systems. Important challenges arise for machine learning algorithms in this scenario, such as reducing energy consumption and minimizing data exchange between devices in different zones. This paper introduces a novel method for accelerated training of parallel Support Vector Machines (pSVMs), based on ensembles, tailored to these kinds of problems. To achieve this, the training set is split into several Voronoi regions. These regions are small enough to permit faster parallel training of SVMs, reducing computational payload. Results from experiments comparing the proposed method with a single SVM and a standard ensemble of SVMs demonstrate that this approach can provide comparable performance while limiting the number of regions required to solve classification tasks. These advantages facilitate the development of energy-efficient policies in WSN.

Ab Interno Ahmed Glaucoma Valve Plugs In An Eye With Persistent Hypotony.

PURPOSE: This case report aims to describe a new method for increasing intraocular pressure (IOP) in patients with acute hypotony resulting from uveitis flare-ups and preexisting glaucoma drainage devices. The temporary glaucoma tube plug method described is effective and safe. METHODS: This case report presents a 47-year-old female patient with a history of chronic panuveitis and secondary glaucoma, who had 2 previously implanted Ahmed glaucoma valves. The patient developed panuveitis flare-up and persistent hypotony. A novel method of ab interno plugging of the glaucoma tubes using 2-0 prolene suture plugs was performed. Following treatment, the IOP increased successfully and remained within the normal range. CONCLUSION: The temporary ab interno glaucoma tube plug method effectively increased IOP in a patient with 2 preimplanted Ahmed glaucoma valves with persistent low IOP due to uveitis.

Acute macular infarctions in pediatric patients with hemoglobin SS disease.

Purpose: To report two cases of symptomatic posterior pole arterial occlusions in patients with hemoglobin SS disease. Observations: Two teenage patients with hemoglobin SS disease presented with visual distortions, and on dilated fundus examination and testing, they were found to have arterial occlusions involving the posterior pole. The patients were evaluated for stroke with head imaging and received exchange transfusion by hematology. Conclusions and Importance: This case series reports the unusual findings of arterial occlusions in the posterior pole resulting in areas of retinal whitening and ischemia in patients with HbSS. While sickle cell retinopathy is typically considered a peripheral retinal disease, these findings underscore the importance of vigilance when examining patients with sickle cell disease.

A Case of Retinal Atherosclerotic Oxalosis due to Hyperoxaluria in a Patient with Short Gut Syndrome.

PURPOSE: To describe a severe case of crystalline retinopathy secondary to hyperoxaluria from short gut syndrome. METHODS: Case report. RESULTS: A 62-year-old Caucasian female with short gut syndrome and end-stage renal disease from renal oxalosis presented with chronic bilateral vision loss. She had previously been treated for presumed occlusive vasculitis. Visual acuity on initial exam was 20/400 OD and 20/100 OS with an afferent pupillary defect of the right eye.Exam revealed attenuated retinal vasculature and diffuse crystalline infiltration of retinal arterial lumens and throughout the retinas bilaterally. Optical coherence tomography revealed inner retinal atrophy with crystalline deposition in the inner retinal layers. Fluorescein angiography demonstrated delayed vascular filling and dropout consistent with severe ischemic vasculopathy. It was concluded that the short-gut syndrome led to over-absorption of oxalate with subsequent hyperoxaluria leading to retinal atherosclerotic oxalosis. CONCLUSION: Retinal calcium oxalate deposits due to hyperoxaluria have been previously noted; however, this degree of severe retinal vascular infiltration has not been described. Our patient was receiving hemodialysis, which is associated with high rebound increases in systemic oxalate concentrations. It is important to keep hyperoxaluria in mind as a potential cause of retinopathy in patients with end-stage renal disease presenting with vision loss.

The sensitivity and specificity of retinal and choroidal folds to distinguish between mild papilloedema and pseudopapilledema.

PURPOSE: To determine if the presence or absence of retinal and choroidal folds on SD-OCT imaging can distinguish between mild papilloedema and pseudopapilledema. DESIGN: Cross-sectional cohort study METHODS: Subjects with optic disc elevation (Frisen grades 1 and 2 only) were eligible to be enrolled prospectively. Pseudopapilledema was defined as a lack of change in optic disc appearance between two visits <6 months apart, and papilloedema was defined as change in optic disc appearance between two visits <6 months apart determined by review of fundus photographs by a masked neuro-ophthalmologist. Three masked neuro-ophthalmologists independently reviewed en face and axial optical coherence tomography (OCT) images of the optic nerve of the study subjects for the presence or absence of retinal and choroidal folds. Concordance was determined when there was agreement between at least 2 of the 3 observers. RESULTS: Forty-five subjects (78 eyes) met inclusion criteria. There were 32 eyes with papilloedema and 46 eyes with pseudopapilledema. Choroidal and/or retinal folds were detected in 38% of eyes (12/32) with papilloedema and 19.6% of eyes (9/46) with pseudopapilledema. Post-hoc analyses eliminated six questionable cases of pseudopapilledema that had ancillary testing suggestive of elevated intracranial pressure and resulted in one remaining eye (2%) with more certain pseudopapilledema that was found to have folds. En face OCT imaging was more sensitive (71%) in detection of folds than axial OCT imaging (57%). CONCLUSIONS: Choroidal and/or retinal folds on OCT are commonly observed in patients with mild papilloedema and are uncommon in those with pseudopapilledema. The presence of folds on OCT in patients presenting with disc elevation suggests papilloedema.

ESPRES: A web application for interactive analysis of multiple pressures in aquatic ecosystems.

ESPRES (Efficient Strategies for anthropogenic Pressure Reduction in European waterSheds) is a web-based Decision Support System (DSS) designed to explore management options for achieving environmental targets in European freshwaters. The tool integrates multi-objective optimization (MOO) algorithms for selecting the best management options in a river basin and models assessing the consequent changes in the water quantity (water flow) and quality (nutrient concentration). The MOO engine identifies Pareto front strategies that are trade-offs between environmental objectives for water bodies and the effort required for reducing the pressures. The web interface provides tools to set the effort perceived by different river basin stakeholders considering technical feasibility, political difficulty, and social acceptability of the alternative options. The environmental impact of management options (scenarios) is assessed with models developed at the European scale. ESPRES enables comparison of management solutions and allows quantifying environmental and socio-economic trade-offs inherent to the decision making process.

Rapidly progressive streptococcus dysgalactiae corneal ulceration associated with erlotinib use in stage IV lung cancer.

PURPOSE: To present a unique case of streptococcus dysgalactiae keratitis with progression to corneal perforation and endophthalmitis, in the setting of epidermal growth factor receptor inhibitor (erlotinib) therapy for advanced non-small cell lung cancer. OBSERVATIONS: An 89-year-old female with non-small cell lung cancer on erlotinib presented with corneal perforation due to infectious keratitis. Microbial cultures grew streptococcus dysgalactiae, a virulent pathogen known to affect immunocompromised patients that has not been previously described to cause infectious keratitis. Despite aggressive medical intervention, the clinical course was complicated by rapid progression to no light perception visual acuity in the setting of endophthalmitis with orbital cellulitis, necessitating evisceration. CONCLUSIONS AND IMPORTANCE: Epidermal growth factor receptor inhibitor therapy can result in significant ocular complications including dry eyes, epithelial keratopathy, non-healing abrasions, infectious keratitis, and rarely, corneal melting and perforation. These side effects can predispose patients to aggressive infections with rare organisms, highlighting the importance of understanding the ocular side effects of systemic chemotherapeutic agents.

A Convergence of Ophthalmic and Life-threatening Emergencies: Acute Angle Closure Glaucoma and Subarachnoid Hemorrhage.

PURPOSE: To report a unique case of acute angle closure glaucoma in the setting of a subarachnoid hemorrhage due to a ruptured cerebral aneurysm. MATERIALS AND METHODS: Observational case report and review of the literature. RESULTS: A 75-year-old woman presented with blurry vision, nausea, vomiting, and left eye pain. She was found to have a complete third nerve palsy, with ptosis, exotropia, hypotropia, and a fixed mydriasis with resultant acute angle closure glaucoma. Pilocarpine was initiated, and neuroimaging revealed a subarachnoid hemorrhage from a ruptured posterior communicating artery aneurysm. The aneurysm was successfully coiled, and outpatient laser iridotomies were subsequently performed. Only 4 prior cases of acute angle closure glaucoma in the setting of a third nerve palsy have been reported in the literature. To our knowledge, this case is the first report of angle closure glaucoma in the setting of a subarachnoid hemorrhage. CONCLUSIONS: This case of a complete third nerve palsy in the setting of a subarachnoid hemorrhage leading to acute angle closure highlights the importance of ruling out this life-threatening diagnosis when neurological signs of increased intracranial pressure and cranial nerve palsies are present.

Topological structures are consistently overestimated in functional complex networks.

Functional complex networks have meant a pivotal change in the way we understand complex systems, being the most outstanding one the human brain. These networks have classically been reconstructed using a frequentist approach that, while simple, completely disregards the uncertainty that derives from data finiteness. We provide here an alternative solution based on Bayesian inference, with link weights treated as random variables described by probability distributions, from which ensembles of networks are sampled. By using both statistical and topological considerations, we prove that the role played by links' uncertainty is equivalent to the introduction of a random rewiring, whose omission leads to a consistent overestimation of topological structures. We further show that this bias is enhanced in short time series, suggesting the existence of a theoretical time resolution limit for obtaining reliable structures. We also propose a simple sampling process for correcting topological values obtained in frequentist networks. We finally validate these concepts through synthetic and real network examples, the latter representing the brain electrical activity of a group of people during a cognitive task.

Usefulness of intravenous heparin to prevent thrombosis of central venous catheter in children.

BACKGROUND: central venous catheter (CVC) thrombosis in children is a main issue and its prevention with intravenous heparin is still controversial. The aim of this study was to evaluate efficacy of intravenous heparin in preventing CVC thrombosis both clinically and macroscopically. METHODS: we conducted a randomized clinical trial in a tertiary care children's hospital with patients <18 years of age with CVC. Experimental group included addition of heparin at 2 IU/ml of intravenous fluids (IV), whereas the control group did not include heparin. RESULTS: seventy six lumen of catheters were included, 38 in each group. Both groups were homogeneous in epidemiological variables. Macroscopic thrombus was found in 27 (35.5%) lumen of catheters. The group with heparin showed thrombus in 7.8% and 63% in the control group (p <0.0001 with relative risk (RR) of 20 and confidence interval (CI) at 95% (5.1-77.2). Clinical evaluation showed adequate flow in the IV of the heparin group in 94.7% and 57.8% in the control group (p <0.001). Blood return through the lumen of catheters with heparin was present in 86.8% and 42.1% in the control group (p <0.001). Mean time for catheters was 14.3 days. There were no side effects or prolonged partial thromboplastin time. CONCLUSIONS: heparin infusion at 2 IU/ml is safe and effective in preventing CVC thrombosis in children.