1,720,955 research outputs found
Effects of photodynamic therapy on choroidal newvessels and normal choroid. An angiographic study
No full textPurpose: The effects of photodynamic therapy (PDT) on the CNV and the normal choroidal vasculature have not yet been completeley understood. We report here the early angiographic changes observed in the CNV and the surrounding choroid in patients with ARMD after PDT.
Methods: Twenty eyes of 20 patients (mean age 76.5 ys) with ARMD and subfoveal "predominantly classic" CNV were considered. Dynamic and still-frame fluorescein angiography (FA) and indocyanine green angiography (ICGA) were carried out in all patients. Angiographic evaluations 7 days before treatment, 30 min, 1 day (only ICGA), 7 and 30 days after PDT were performed in all patients. No patients had had previous PDT or laser treatment.
Results: 1) PDT effects on the CNV complex. Within 30 min after PDT CNV showed, in 3 eyes (15 %), hypofluorescence in early and late phases due to closure of the neovascular complex, while in 17 eyes (85%) CNV appeared hyperfluorescent in the early phases. One day after PDT this hyperfluorescence seemed to decrease. At 1 week all eyes showed a hypofluorescent CNV. However, within 4 weeks most CNV demonstrated a progressive reopening with increasing fluorescence intensity, quite resembling that of pre-treatment angiography. 2) PDT effects on choroidal circulation. Thirty minutes after PDT ICGA showed in 11 eyes (55%) a mid-phase hyperfluorescence on the laser spot area, followed by deep choroidal leakage of dye even beyond the boundaries of the treated area. In these eyes, at 1 day, an intense and well-delineated early hypofluorescent spot, covering the whole PDT area, was observed. A black spot of hypofluorescence over the treatment area could be observed in all eyes, 7 days after PDT. A choriocapillary loss, changes of choroidal filling with marked decrease in the overall density of choroidal vessels, was observed. Though they progressively reopen in the following days, an area of hypofluorescent choroid still persisted in all patients, as observed 1 month after PDT.
Conclusions: PDT is associated to a dynamic sequence of vascular changes. It produces a strong occlusive effect on the CNV but lighter collapsing changes are also visible within the normal choroid exposed to the laser spot. These "side-effects" on normal choroidal circulation can sometimes determine closure of major vessels. Most changes on both CNV and the treated choroid are temporary, even though a residual slight hypoperfusion can be appreciated in the treatment spot. This study seems to demonstrate that PDT is only partially selective. The different impact on the surrounding choroid could influence the rate of recurrences
Macular vitelliform degeneration in adults: Indocyanine green angiographic findings
No full textPurpose: The adult macular vitelliform degeneration (AMVD) is a macular disease similar to Best vitelliform dystrophy, but occuring in adults with normal or subnormal electro-oculogram. It is characterized by the accumulation of lipofuscin-like material within and beneath the retinal pigment epithelium. The aim of this study was to analyze the choroidal perfusion and permeability in patients with AMVD.
Methods: We retrospectively analyzed dynamic and still-frame indocyanine green angiographies (ICGA) in 40 consecutive patients with AMVD (64 eyes). We studied the pattern of choroidal filling at the posterior pole in the early phases of the dynamic ICGA performed with a SLO (Rodenstock, Germany), and the alterations of the choroidal permeability observed with a still-frame ICGA digitized fundus camera (Topcon 50 IA, Japan).
Results: The choroidal filling appeared normal in all patients. In 29 patients (52 eyes) ICGA revealed choroidal vascular hyperpermeability seen as areas of hyperfluorescence that were detectable at the posterior pole in the mid and late phases of the angiogram. The choroidal hyperpermeability was often present in the fellow eye even though no subretinal macular material was evident.
Conclusion: The angiographic changes observed in these patients with adult macular vitelliform degeneration seem to underline an important pathogenetic role of the choroidal vasculature. The interpretation of the detected choroidal hyperpermeability, common to other diseases, such as central serous chorioretinopathy, still needs to be clarified
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
HIV-1-mediated delivery of a short hairpin RNA targeting vascular endothelial growth factor in human retinal pigment epithelium cells
No full textBackground: Vascular endothelial growth factor (VEGF) has been shown to play a major role in the pathological neovascularisation that occurs in degenerative retinal diseases like age-related macular degeneration (AMD). Although several approaches to attenuate VEGF show significant promise, repeated treatments are required to achieve therapeutic benefits. As lentiviruses efficiently and stably infect resting cells, a human immunodeficiency virus type 1 (HIV-1)-based vector was used for the delivery and long-term endogenous expression of a short hairpin RNA (shRNA) specific for VEGF in postmitotic human retinal pigment epithelium (RPE) cells.
Methods: An HIV-1 vector expressing a shRNA targeting VEGF was developed and adopted to transduce RPE cell cultures, in both normoxic and hypoxic conditions in vitro. Intracellular VEGF expression was analysed by western blotting, and the release of VEGF in culture supernatants was determined by ELISA.
Results: At least 90% of RPE cells were successfully transduced by HIV-1 virions. Inhibition of VEGF expression and reduction by 95% of VEGF release in transduced cells were achieved. Moreover, shRNA-VEGF effectively and specifically prevented hypoxia-induced VEGF upregulation.
Conclusion: HIV-1-mediated delivery of a shRNA-VEGF leading to gene expression knockdown could represent a novel therapeutic strategy against neovascularisation-related eye diseases
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