1,721,120 research outputs found
Recent advances in mesenchymal stem cell immunomodulation. The role of microvesicles
No full textMesenchymal stem cells are the most widely used cell phenotype for therapeutic applications, the main reasons being their well-established abilities to promote regeneration of injured tissues and to modulate immune responses. Efficacy was reported in the treatment of several animal models of inflammatory and autoimmune diseases and, in clinical settings, for the management of disorders such as GVHD, Systemic Lupus Erythematosus, multiple sclerosis and inflammatory bowel disease. The effects of mesenchymal stem cells are believed to be largely mediated by paracrine signals, and several secreted molecules have been identified as contributors to the net biological effect. Recently, it has been recognized that bioactive molecules can be shuttled from cell to cell packed in microvesicles, tiny portions of cytoplasm surrounded by a membrane. Coding and non-coding RNAs are also carried in such microvesicles, transferring relevant biological activity to target cells. Several reports indicate that the regenerative effect of mesenchymal stem cells can be reproduced by microvesicles isolated from their culture medium. More recent evidence suggests that the immunomodulatory effects of mesenchymal stem cells are also at least partially mediated by secreted microvesicles. These findings allow better understanding of the mechanisms involved in cell-to-cell interaction and may have interesting implications for the development of novel therapeutic tools in place of the parent cells
Free radicals and brain damage in newborns with hypoxic-ischemic lesion
No full textFree radicals (FR) are highly reactive chemical molecules containing one or more unpaired electrons. Oxygen-derived free radicals, collectively termed reactive oxygen species (ROS), are normally produced in living organisms. When over produced, they are major mediators of cell and tissue injury. There is a critical balance between free radical generation and antioxidant defenses. Oxidative stress in vivo is a degenerative process due to the over production and propagation of FR reactions. FR reactions lead to oxidation of lipids, proteins, polysaccharides and to DNA damage. Newborns and particularly preterm infants are very susceptible to FR oxidative damage. In these subjects, there is evidence of an imbalance between antioxidant and oxidant-generating systems enhancing oxidant injury
The role of extracellular vesicles (Evs) in the epigenetic regulation of bone metabolism and osteoporosis
Full text linkExtracellular vesicles (EVs) are complex phospholipidic structures actively released by cells. EVs are recognized as powerful means of intercellular communication since they contain many signaling molecules (including lipids, proteins, and nucleic acids). In parallel, changes in epigenetic processes can lead to changes in gene function and finally lead to disease onset and progression. Recent breakthroughs have revealed the complex roles of non-coding RNAs (microRNAs (miRNAs) and long non-coding RNAs (lncRNAs)) in epigenetic regulation. Moreover, a substantial body of evidence demonstrates that non-coding RNAs can be shuttled among the cells and tissues via EVs, allowing non-coding RNAs to reach distant cells and exert systemic effects. Resident bone cells, including osteoclasts, osteoblasts, osteocytes, and endothelial cells, are tightly regulated by non-coding RNAs, and many of them can be exported from the cells to neighboring ones through EVs, triggering pathological conditions. For these reasons, researchers have also started to exploit EVs as a theranostic tool to address osteoporosis. In this review, we summarize some recent findings regarding the EVs’ involvement in the fine regulation of non-coding RNAs in the context of bone metabolism and osteoporosis
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
Exosome Treatment of Bronchopulmonary Dysplasia: How Pure Should Your Exosome Preparation Be?
No full textWe read with interest the article by Willis and colleagues (1) about the striking therapeutic efficacy of exosomes isolated from mesenchymal stem cells (MSCs) in a mouse model of bronchopulmonary dysplasia (BPD). BPD is a multifactorial, chronic lung disease that occurs in 40–45% of infants born at <29 weeks of gestation and is associated with significant long-term pulmonary morbidities. Because no effective treatment is available, there is an urgent need for novel therapies capable of reversing the course of the disease. Pioneering work done by Hansmann and colleagues (2) demonstrated that the intravenous administration of MSCs or MSC-conditioned medium (MSC-CM) reduced lung injury and inflammation, and prevented pulmonary hypertension in an animal model of hyperoxia-induced BPD. These results were confirmed by other groups, and we obtained similar results after administering human amniotic fluid cells (3). Lee and colleagues (4) subsequently showed that the exosome-enriched fraction of MSC-CM was therapeutically active, paving the way for the use of these biological nanoparticles in the treatment of BPD. Exosomes are membrane vesicles that convey a variety of metabolic signals between cells, and clinical-grade exosomes can be produced for use in therapeutic applications, with considerable advantages over living cells in terms of safety, applicability, and cost (5)
Different decellularization methods to characterize the extracellular matrix of rhabdomyosarcoma and healthy muscle tissue
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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
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