1,721,030 research outputs found
Editorial: Role of Ribonucleases in Immune Response Regulation During Infection and Cancer
No full textSpatio-Temporal Changes of Extracellular Matrix (ECM) Stiffness in the Development of the Leech Hirudo verbana
Full text linkThe invertebrate leech Hirudo verbana represents a powerful experimental animal model for improving the knowledge about the functional interaction between the extracellular matrix (ECM) and cells within the tissue microenvironment (TME), and the key role played by ECM stiffness during development and growth. Indeed, the medicinal leech is characterized by a simple anatomical organization reproducing many aspects of the basic biological processes of vertebrates and in which a rapid spatiotemporal development is well established and easily assessed. Our results show that ECM structural organization, as well as the amount of fibrillar and non-fibrillar collagen are deeply different from hatching leeches to adult ones. In addition, the changes in ECM remodelling occurring during the different leech developmental stages, leads to a gradient of stiffness regulating both the path of migratory cells and their fates. The ability of cells to perceive and respond to changes in ECM composition and mechanics strictly depend on nuclear or cytoplasmic expression of Yes-Associated Protein 1 (YAP1), a key mediator converting mechanical signals into transcriptional outputs, expression, and activation
Dynamic relationship among extracellular matrix and body wall cells in Hirudo verbana morphogenesis
Full text linkA great bulk of recent experimental evidence suggests the key role of the complex crosstalk between the extracellular matrix (ECM) and the cellular component of tissues during morphogenesis and embryogenesis. In particular, remodeling of the ECM and of its physical interactions pattern with surrounding cells represent two crucial processes that might be involved in muscle development. However, little information is available on this topic, especially on invertebrate species. To obtain new insights on how tuning the ECM microenvironment might drive cellular fate during embryonic development, we used the invertebrate medicinal leech Hirudo verbana as a valuable experimental model, due to its simple anatomy and the recapitulation of many aspects of the basic biological processes of vertebrates. Our previous studies on leech post-embryonic development have already shown the pivotal role of ECM changes during the growth of the body wall and the role of Yes-associated protein 1 (YAP1) in mechanotransduction. Here, we suggest that the interactions between stromal cell telocytes and ECM might be crucial in driving the organization of muscle layers during embryogenesis. Furthermore, we propose a possible role of the pleiotropic enzyme HvRNASET2 as a possible modulator of collagen deposition and ECM remodeling not only during regenerative processes (as previously demonstrated) but also in embryogenesis
HvRNASET2 regulate connective tissue and collagen i remodeling during wound healing process
Full text linkSeveral studies have recently demonstrated that the correct regeneration of damaged tissues and the maintaining of homeostasis after wounds or injuries are tightly connected to different biological events, involving immune response, fibroplasia, and angiogenetic processes, in both vertebrates and invertebrates. In this context, our previous data demonstrated that the Hirudo verbana recombinant protein rHvRNASET2 not only plays a pivotal role in innate immune modulation, but is also able to activate resident fibroblasts leading to new collagen production, both in vivo and in vitro. Indeed, when injected in the leech body wall, which represents a consolidated invertebrate model for studying both immune response and tissue regeneration, HvRNASET2 induces macrophages recruitment, fibroplasia, and synthesis of new collagen. Based on this evidence, we evaluate the role of HvRNASET2 on muscle tissue regeneration and extracellular matrix (ECM) remodeling in rHvRNASET2-injected wounded leeches, compared to PBS-injected wounded leeches used as control. The results presented here not only confirms our previous evidence, reporting that HvRNASET2 leads to an increased collagen production, but also shows that an overexpression of this protein might influence the correct progress of muscle tissue regeneration. Moreover, due to its inhibitory effect on vasculogenesis and angiogenesis, HvRNASET2 apparently interfere with the recruitment of the myoendothelial vessel-associated precursor cells that in turn are responsible for muscle regeneration during wound healing repair
Role of the extracellular matrix during the postembryonic development of the medicinal leech Hirudo verbana
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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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