1,720,982 research outputs found
Effetti dell'acquisizione del fenotipo senescente sulle cellule staminali dell'epitelio pigmentato retinico
Full text linkGli approcci di medicina rigenerativa basati su cellule staminali mesenchimali (MSC) sono stati studiati per trattare diverse malattie associate all'invecchiamento, inclusa la degenerazione maculare legata all'età (DMLE). La perdita delle cellule dell'epitelio pigmentato retinico (EPR) si verifica all'inizio della DMLE e il loro trapianto ha il potenziale per rallentare la progressione della malattia. L'EPR umano contiene una sottopopolazione di cellule - cellule staminali EPR adulte (RPESC) - che sono in grado di auto-rinnovarsi e di differenziarsi in cellule RPE in vitro. Tuttavia, i cambiamenti di MSC correlati all'età comportano perdita di funzione e acquisizione di un fenotipo secretorio associato alla senescenza (SASP), che può contribuire al mantenimento di uno stato cronico di infiammazione di basso grado nei tessuti e negli organi. In uno studio precedente abbiamo isolato, caratterizzato e RPESC differenziati. In questa sperimentazione abbiamo indotto senescenza replicativa in RPESCs e testato la loro acquisizione del fenotipo della senescenza e della SASP così come la capacità di differenziazione di RPESC giovani e senescenti. Gli RPESC senescenti hanno mostrato una capacità di proliferazione significativamente ridotta, un'alta attività β-galattosidasi associata alla senescenza e l'acquisizione di SASP. I geni specifici per RPE erano sottoregolati e l'espressione della proteine p21 e p53 era sovraregolata. Questi risultati documentano gli effetti della senescenza e dell'acquisizione di SASP sulla capacità di differenziazione di RPESC e sottolineano la necessità di una maggiore comprensione del loro ruolo nella patogenesi della DMLE.Regenerative medicine approaches based on mesenchymal stem cells (MSCs) are being investigated to treat several aging-associated diseases, including age-related macular degeneration (AMD). Loss of retinal pigment epithelium (RPE) cells occurs early in AMD, and their transplant has the potential to slow disease progression.
The human RPE contains a subpopulation of cells - adult RPE stem cells (RPESCs) – that are capable of self-renewal and of differentiating into RPE cells in vitro. However, age-related MSC changes involve loss of function and acquisition of a senescence-associated secretory phenotype (SASP), which can contribute to the maintenance of a chronic state of low-grade inflammation in tissues and organs.
In a previous study we isolated, characterized, and differentiated RPESCs. Here, we induced replicative senescence in RPESCs and tested their acquisition of the senescence phenotype and the SASP as well as the differentiation ability of young and senescent RPESCs.
Senescent RPESCs showed a significantly reduced proliferation ability, high senescence-associated β-galactosidase activity, and SASP acquisition. RPE-specific genes were downregulated and p21 and p53 protein expression was upregulated.
These findings document the effects of senescence and SASP acquisition on RPESC differentiation ability and highlight the need for a greater understanding of their role in AMD pathogenesis
Juxtapapillary Retinal Capillary Hemangioma: New Therapeutic Strategies
Full text linkThe treatment of juxtapapillary retinal capillary hemangiomas (JRCHs) is still a therapeutic dilemma without established guidelines. Because of the location of these hemangiomas on or adjacent to the optic nerve, treatment is difficult and complex, especially when JRCHs are located in the papillomacular bundle. This manuscript reviews the clinically relevant data on literature regarding the treatment of JRCHs, focusing on novel combined therapies that have shown promising results in these lesions
Correlation Between Microperimetry Findings And Visual Outcome After 25-gauge Vitrectomy In Idiopathic Macular Hole
No full textEpiretinal membrane surgery for combined hamartoma of the retina and retinal pigment epithelium: Role of multimodal analysis
No full text
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
Negative staining of the vitreous with the use of vital dyes
No full textPurpose: The vitreous cortex, epiretinal membrane (ERM), and inner limiting membrane (ILM) are transparent tissues and are thus difficult to visualize. Staining these structures can increase the efficiency of a nontraumatic removal. Methods: The surgeon performs a partial core vitrectomy and induces a posterior vitreous detachment. The vital dye is then injected into the retrohyaloid space in balanced salt solution (BSS). The dyes used are TWIN (Alchimia srl, Padova, Italy), MembraneBlue-Dual (DORC International, Zuidland, the Netherlands), and Doubledyne (Alfa Intes, Casoria, Italy). The surgeon can complete the vitrectomy and gradually aspirate the dye with the probe. Once the vitrectomy is complete, the surgeon can perform the peeling of the ERM without the need to reinject the vital dye over the macula. Results: The presence of the dye over the macula facilitates visualization of the vitreous cortex by blocking the red reflex and increasing the contrast power of the coaxial light probe during the vitrectomy. This allows a negative coloration of the vitreous because the dye acts by increasing the visibility of the surrounding BSS and not the vitreous itself. Conclusions: We describe a new chromovitrectomy technique using the same dye to increase the visualization of the vitreous, posterior hyaloid, ERM, and ILM
- …
