1,721,215 research outputs found
OCULAR AND GENETIC CHARACTERISTICS OF PATIENTS SURVIVING LONG-LASTING TYPE 1 DIABETES WITHOUT VASCULAR COMPLICATIONS
Full text linkBackground and aims: Recent evidences suggest that a group of patients with either type 1 or type 2 diabetes may be spared by microvascular complications, even after a long-lasting disease. The aim of this study was to investigate the clinical and genetic characteristics of patients with long-lasting (i.e. > 30 years) type 1 diabetes who are not affected by systemic microvascular complications. The characterization of this very rare niche of patients may reveal new insights into the diabetes-associated microvascular complications’ pathogenesis.
Material and methods: In this case-control study, Caucasian patients with type 1 diabetes for at least 30 years and without evidence or history of systemic microvascular complications (i.e. diabetic retinopathy [DR] or diabetic nephropathy) were prospectively enrolled. Patients underwent a complete ophthalmological assessment, including structural optical coherence tomography (OCT) and OCT angiography (OCTA). Furthermore, blood samples were obtained in all subjects. OCT and OCTA images were analyzed with previous validated algorithms in order to quantify inner and outer retinal thicknesses, as well as retinal and choroidal perfusion. For the latter analyses, a control group of 30 healthy controls was included for comparisons. Blood samples were analyzed with whole-exome sequencing (WES) in order to determine whether in our study cohort there were variants in well-studied genes that were previously suggested to be associated (i.e. either protective or causative) with diabetes-associated microvascular complications, as well as to investigate presence of causative or protective variants.
Results: Twenty-seven subjects (12 females, 15 males) with long-lasting type 1 diabetes and without microvascular complications were included. Mean±SD age was 51.4±9.5 years. Mean±SD duration of diabetes was 37.7±6.5 years. We selected for rare missense variants that were either protective or causative for DR. No differences in OCT and OCTA metrics were detected between patients and healthy controls.
Conclusions: This study identified genes that seem to be associated with a lower vs. greater risk of developing DR. The identification of these genes might grant strategic and personalized therapeutic plans in patients with diabetes. Finally, our patients did not show retinal structural and/or vascular changes, the latter finding suggesting that these patients may be protected by clinical and subclinical alterations.Introduzione: Recenti evidenze suggeriscono che un gruppo di pazienti con diabete di tipo 1 o di tipo 2 può essere risparmiato da complicanze microvascolari, anche dopo una malattia di lunga durata. Lo scopo di questo studio era quello di indagare le caratteristiche cliniche e genetiche di pazienti con diabete di tipo 1 di lunga durata (> 30 anni) che non sono affetti da complicanze microvascolari sistemiche. La caratterizzazione di questa rarissima nicchia di pazienti può rivelare nuove intuizioni sulla patogenesi delle complicanze microvascolari associate al diabete.
Materiali e metodi: In questo studio caso-controllo, sono stati arruolati in modo prospettico pazienti caucasici con diabete di tipo 1 da almeno 30 anni e senza segni o storia di complicanze microvascolari sistemiche (es. retinopatia diabetica [RD] o nefropatia diabetica). I pazienti sono stati sottoposti a una valutazione oftalmologica completa, compresa la tomografia a coerenza ottica (OCT) e l'angiografia OCT (OCTA). Inoltre, sono stati prelevati campioni di sangue in tutti i soggetti. Le immagini OCT e OCTA sono state analizzate con precedenti algoritmi convalidati al fine di quantificare gli spessori retinici interni ed esterni, nonché la perfusione retinica e coroideale. Per queste ultime analisi, è stato incluso un gruppo di controllo di 30 controlli sani per confronto. I campioni di sangue sono stati analizzati con il sequenziamento dell'intero esoma (WES) al fine di determinare se nella nostra coorte di studio esistessero varianti in geni ben studiati che in precedenza erano stati suggeriti per essere associati (cioè protettivi o causali) a complicanze microvascolari associate al diabete, nonché per indagare la presenza di varianti causative o protettive.
Risultati: Sono stati inclusi 27 soggetti (12 femmine, 15 maschi) con diabete di tipo 1 di lunga durata e senza complicanze microvascolari. L'età media ± SD era di 51,4 ± 9,5 anni. La durata media ± DS del diabete era di 37,7 ± 6,5 anni. Abbiamo selezionato varianti missenso rare che erano protettive o causative per DR. Non sono state rilevate differenze nei valori OCT e OCTA tra pazienti e controlli sani.
Conclusioni: Questo studio ha identificato i geni che sembrano essere associati a un rischio inferiore rispetto a quello maggiore di sviluppare RD. L'identificazione di questi geni potrebbe garantire piani terapeutici strategici e personalizzati nei pazienti con diabete. Infine, i nostri pazienti non hanno mostrato alterazioni strutturali e/o vascolari retiniche, quest'ultima scoperta sembra suggerire che questi pazienti potrebbero essere protetti anche da alterazioni cliniche e subcliniche
Perifoveal exudative vascular anomalous complex in a highly myopic eye
No full text'Perifoveal Exudative Vascular Anomalous Complex' (PEVAC) is a perifoveal, unilateral, isolated, perifoveal aneurysm, in otherwise healthy patients. Here, we report a case of PEVAC in a highly myopic eye of a 86-year-old woman affected by a visual decline in the right eye (best-corrected visual acuity of 20/100). She had no other relevant past conditions and/or ocular impairment. Fundus examination in the right eye showed myopic chorioretinal degeneration with a concomitant PEVAC. Structural optical coherence tomography (OCT) showed a round lesion with a hyperreflective wall associated with intraretinal cystic spaces. OCT-angiography nicely disclosed an isolated large aneurysmal retinal dilation featuring the PEVAC with detectable flow in superficial capillary plexus, deep capillary plexus, and avascular slab. This case highlights the importance of discerning between different vascular disorders of the macula, in order to be able to offer the right treatment and/or follow-up to the patient
Reproducibility of vessel density, fractal dimension, and foveal avascular zone using 7 different optical coherence tomography angiography devices
No full textRefers to: Federico Corvi, Marco Pellegrini, Stefano Erba, Mariano Cozzi, Giovanni Staurenghi, Andrea Giani Reproducibility of Vessel Density, Fractal Dimension, and Foveal Avascular Zone Using 7 Different Optical Coherence Tomography Angiography Devices American Journal of Ophthalmology, Volume 186, February 2018, Pages 25-3
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
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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