1,720,959 research outputs found
Retinal electrofunctional alterations in patients affected by juvenile diabetes.
No full textAim: The purpose of the study was to evaluate the internal retinal layers functionality and to document the correlations with metabolic control parameters in patients affected by diabetes mellitus type I free.
Materials and methods: A group of 40 patients affected by insulin
dependent diabetes mellitus type 1 were examined by means of the scotopic threshold response (STR) and oscillatory
potentials (OPs). The results were compared with the data obtained from a group of 20 healthy subjects.
Results: Statistically significant correlations have been identified
between the STR values and the levels of glycosylated haemoglobin and glycemia at the time of the exam.
Conclusion: The results show the presence of a retinal functionality
alteration located mainly in the internal retinal layers.
This level generates the STR response which is produced specially by the amacrine cells that are sensible to the damage
of the retinal microcirculation
Preliminary study on combined pharmacological and laser treatment in optic pit serous maculopathy after literature review.
No full textThe pit of the optic nerve head (ON) is a rare congenital defect that sometimes presents itself with a maculopathy of various neuroretinal layers for unknown reason. This study was focused, before and after pharmacological and parasurgical treatment, on the structural and functional visual assessment in a patient with optic pit maculopathy (OPM). In order to achieve this the latest generation of hi-tech diagnostic tests were used, such as Spectral-Domain Optical Coherence Tomography (SD-OCT), Visual Evoked Potentials (VEP), full-field Electroretinography (ERG), multifocal ERG (mfERG), Microperimetry (MP-1), Standard Automated Perimetry (SAP), Fluorescein Angiography (FA) and Indocyanine Green Angiography (ICG). The research was conducted through a review of past and recent literature
Corneal haze in course of Fuchs' endothelial dystrophy.
No full textThis article describes the observations obtained with confocal microscopy (CM) on the corneal structure in course of corneal edema in a patient with Fuchs endothelial corneal dystrophy (FD). The patient was a 40 year old male, suffering from second stage FD, in course of corneal edema and bullous keratopathy. The tissue structure was analyzed with CM confoscan CS4 (Nidek Technologies(®), Birmingham, UK) using the 40x mode. The CM has shown the presence of gaps due to corneal edema and a diffuse stromal hyper reflectivity related to the alteration of the extracellular matrix. It has also showed the presence of binucleate cells, assimilable to keratocytes, in cytokinesis which presented a typical fusiform aspect with two highly reflective nuclei awaiting cell division. The total number of cells was much lower than that of healthy control subjects of similar age, sex and race. The CM in this case suggests a significantly lower number of cells, presumably keratocytes, compared to normal range, but mostly it shows the presence of cells undergoing cytokinesis, which witnesses the active processes of collagenogenesis and possible vasculogenesis that represent early stages of loss of the normal corneal transparency
Detection of myopic foveoschisis by means of hi-tech diagnostic exams.
No full textAim: Myopic foveoschisis (MF) is the splitting of the retinal
layers in the fovea, probably caused by the excessive elongation of the ocular globe in patients with high myopia (HM). The aim of the study was to evaluate the morphological
and functional characteristics of the retinal area affected
by MF.
Methods: Five eyes of 10 patients were diagnosed with MF by spectral domain optical coherence tomography (SD-OCT). Patients were examined using both a nineteen-line raster scan and a three-dimensional scan during the same visit. All subjects underwent monocular instrumental registration of the visual characteristics of macular areas such as macular thickness, retinal functionality and sensitivity values. The patients and control subjects underwent also multifocal electroretinography
(mfERG) and Microperimetry (MP-1) and the obtained results were compared to show the effects of pathologies of the inner and outer retinal layers. The statistic analysis with nonparametric tests for the examined variables, and in particular the Wilcoxon Signed Ranks test for paired data, was performed.
Results: The two tailed test yielded statistically significant values in the MF group for all three studied characteristics, OCT, mfERG and MP-1, in both the first and second ring. In the third area between 5° and 10° the alterations of the values proved to be statistically significant only for macular thickness
measured by OCT and amplitude of the P1 wave shown in the mfERG results.
Conclusions: The nineteen-line raster scan and the three-dimensional
scan mode of SD-OCT were useful for the detection
of the pathologies that accompany MF, also providing important informations before and after a possible vitreo-retinal
surgery. However these informations must be supported by objective and subjective functional tests just as mfERG and MP-1
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Surgical management by means of electroretinographic examination during extracorporeal circulation
No full textBackground: Neurological and/or neuropsychological damages are important complications of cardiosurgical interventions. This study determined if the timing of the electroretinographic (ERG) ocular exam can assess intraoperative brain damage of patients supported by extracorporeal circulation (ECC) during cardiosurgical interventions. Materials and methods: The authors illustrate an ERG technique being able to evaluate on 12 patients during cardiosurgical interventions and in conditions of ECC, both hypothermic and normothermic, the possibility to forecast the potential neurological and/or neuropsychological damages. Results: The ERG waves obtained are compared before and after ECC in various conditions of corporeal temperature. During ECC all patients had a change of ERG waves, whom was particularly significant for patients operated in conditions of induced hypothermia. Conclusions: The observations reported by ERG provide new and important information in support of the potential organic suffering. This exam can assess the defect of the waves indicative of insufficient ocular and brain perfusion of patients supported by ECC during cardiosurgical interventions
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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