1,679 research outputs found
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Improving Visual Field Examination of the Macula Using Structural Information
Purpose: To investigate a novel approach for structure-function modeling in glaucoma to improve visual field testing in the macula.
Methods: We acquired data from the macular region in 20 healthy eyes and 31 with central glaucomatous damage. Optical coherence tomography (OCT) scans were used to estimate the local macular ganglion cell density. Perimetry was performed with a fundus-tracking device using a 10-2 grid. OCT scans were matched to the retinal image from the fundus perimeter to accurately map the tested locations onto the structural damage. Binary responses from the subjects to all presented stimuli were used to calculate the structure-function model used to generate prior distributions for a ZEST (Zippy Estimation by Sequential Testing) Bayesian strategy. We used simulations based on structural and functional data acquired from an independent dataset of 20 glaucoma patients to compare the performance of this new strategy, structural macular ZEST (MacS-ZEST), with a standard ZEST.
Results: Compared to the standard ZEST, MacS-ZEST reduced the number of presentations by 13% in reliable simulated subjects and 14% with higher rates (≥20%) of false positive or false negative errors. Reduction in mean absolute error was not present for reliable subjects but was gradually more important with unreliable responses (≥10% at 30% error rate).
Conclusions: Binary responses can be modeled to incorporate detailed structural information from macular OCT into visual field testing, improving overall speed and accuracy in poor responders.
Translational Relevance: Structural information can improve speed and reliability for macular testing in glaucoma practice
Isolation of EpH4 mammary epithelial cell subpopulations which differ in their morphogenetic properties
Summary: EpH4 is a nontumorigenic cell line derived from spontaneously immortalized mouse mammary gland epithelial cells (Fialka et al., 1996). When grown in collagen gels, EpH4 cells give rise to different types of structures, e.g., solid cords or branching tubes. By removing and subsequently dissociating single three-dimensional colonies of defined morphology, we have isolated six clonal subpopulations of EpH4 cells which display distinct morphogenetic properties in collagen gel cultures. Thus, cells from the H1B clone form branching cords devoid of a central lumen, K3A3 cells from cords enclosing small multifocal lumina, and J3B1 cells form large cavitary structures containing a wide lumen. I3G2 cells form either cords or tubes, depending on the type of serum added to the culture medium. Finally, when grown in serum-free medium, Be1a cells form spherical cysts, whereas Be4a cells form long, extensively branched tubes. In additional assays of morphogenesis, i.e., cell sandwiching between two collagen gels or culture on a thick layer of Matrigel (a laminin-rich extracellular matrix), all clones form epithelial-cell-lined cavitary structures, except H1B cells which are unable to generate lumina under these conditions. The EpH4 sublines we have isolated provide an in vitro system for studying the mechanisms responsible for lumen formation and branching morphogenesis, as well as for identifying the factors which subvert these developmental processes during mammary carcinogenesi
Analyzing and Decoding Natural Reach-and-Grasp Actions Using Gel, Water and Dry EEG Systems
Reaching and grasping is an essential part of everybody’s life, it allows meaningful interaction with the environment and is key to independent lifestyle. Recent electroencephalogram (EEG)-based studies have already shown that neural correlates of natural reach-and-grasp actions can be identified in the EEG. However, it is still in question whether these results obtained in a laboratory environment can make the transition to mobile applicable EEG systems for home use. In the current study, we investigated whether EEG-based correlates of natural reach-and-grasp actions can be successfully identified and decoded using mobile EEG systems, namely the water-based EEG-VersatileTM system and the dry-electrodes EEG-HeroTM headset. In addition, we also analyzed gel-based recordings obtained in a laboratory environment (g.USBamp/g.Ladybird, gold standard), which followed the same experimental parameters. For each recording system, 15 study participants performed 80 self-initiated reach-and-grasp actions toward a glass (palmar grasp) and a spoon (lateral grasp). Our results confirmed that EEG-based correlates of reach-and-grasp actions can be successfully identified using these mobile systems. In a single-trial multiclass-based decoding approach, which incorporated both movement conditions and rest, we could show that the low frequency time domain (LFTD) correlates were also decodable. Grand average peak accuracy calculated on unseen test data yielded for the water-based electrode system 62.3% (9.2% STD), whereas for the dry-electrodes headset reached 56.4% (8% STD). For the gel-based electrode system 61.3% (8.6% STD) could be achieved. To foster and promote further investigations in the field of EEG-based movement decoding, as well as to allow the interested community to make their own conclusions, we provide all datasets publicly available in the BNCI Horizon 2020 database (http://bnci-horizon-2020.eu/database/data-sets)
Stam: a framework for spatio-temporal affordance maps
A�ordances have been introduced in literature as action op-
portunities that objects o�er, and used in robotics to semantically rep-
resent their interconnection. However, when considering an environment
instead of an object, the problem becomes more complex due to the
dynamism of its state. To tackle this issue, we introduce the concept
of Spatio-Temporal A�ordances (STA) and Spatio-Temporal A�ordance
Map (STAM). Using this formalism, we encode action semantics re-
lated to the environment to improve task execution capabilities of an
autonomous robot. We experimentally validate our approach to support
the execution of robot tasks by showing that a�ordances encode accurate
semantics of the environment
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Improving perimetric examination of the macular visual field using structural information
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Cataract and optic disk drusen in a patient with glycogenosis and di George syndrome: clinical and molecular report
Background
We report the ophthalmic findings of a patient with type Ia glycogen storage disease (GSD Ia), DiGeorge syndrome (DGS), cataract and optic nerve head drusen (ONHD).
Case presentation
A 26-year-old white woman, born at term by natural delivery presented with a post-natal diagnosis of GSD Ia. Genetic testing by array-comparative genomic hybridization (CGH) for DGS was required because of her low levels of serum calcium. The patient has been followed from birth, attending the day-hospital every six months at the San Paolo Hospital, Milan, outpatient clinic for metabolic diseases and previously at another eye center. During the last day-hospital visit, a complete eye examination showed ONHD and cataract in both eyes. Next Generation Sequencing (NGS) was subsequently done to check for any association between the eye problems and metabolic aspects.
Conclusions
This is the first description of ocular changes in a patient with GSD Ia and DGS. Mutations explaining GSD Ia and DGS were found but no specific causative mutation for cataract and ONHD. The metabolic etiology of her lens changes is known, whereas the pathogenesis of ONHD is not clear. Although the presence of cataract and ONHD could be a coincidence; the case reported could suggest that hypocalcemia due to DGS could be the common biochemical pathway
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