1,720,955 research outputs found
Methods to Investigate the Secretome of Senescent Cells
No full textThe word "secretome" was first used to describe the proteins that cells secrete under different circumstances; however, recent studies have proven the existence of other molecules such as RNA and chemical compounds in the secretome. The study of secretome has significance for the diagnosis and treatment of disease as it provides insight into cellular functions, including immune responses, development, and homeostasis. By halting cell division, cellular senescence plays a role in both cancer defense and aging by secreting substances known as senescence-associated secretory phenotypes (SASP). A variety of techniques could be used to analyze the secretome: protein-based approaches like mass spectrometry and protein microarrays, nucleic acid-based methods like RNA sequencing, microarrays, and in silico prediction. Each method offers unique advantages and limitations in characterizing secreted molecules. Top-down and bottom-up strategies for thorough secretome analysis are became possible by mass spectrometry. Understanding cellular function, disease causes, and proper treatment targets is aided by these methodologies. Their approaches, benefits, and drawbacks will all be discussed in this review
Methods to Detect and Compare Cellular and Mitochondrial Changes in Senescent and Healthy Mesenchymal Stem Cells
No full textCellular senescence is a multifaceted process marked by irreversible cell cycle arrest in response to stressors such as DNA damage, oxidative stress, and telomere shortening, leading to significant cellular and mitochondrial alterations. These changes impact mesenchymal stem cell (MSC) function, affecting their differentiation, self-renewal, and regenerative abilities. Senescent MSCs adopt the senescence-associated secretory phenotype (SASP), characterized by the secretion of pro-inflammatory factors that propagate senescence to neighboring cells. Key features of senescent MSCs include altered morphology, reduced proliferative and differentiation capacity, and changes in their secretome. Mitochondrial dysfunction plays a central role in this process, impairing stemness, increasing oxidative stress, and contributing to cellular aging by generating reactive oxygen species (ROS). The chapter provides an overview of various methods to analyze senescent cells, including techniques to detect changes in cell proliferation, DNA damage, apoptosis, and mitochondrial function. It also highlights assays for mitochondrial alterations such as fluorescent staining, membrane potential analysis, and mitophagy evaluation. These tools are essential for understanding the complex mechanisms of cellular senescence and mitochondrial dysfunction, offering insights into aging and potential therapeutic strategies
Mesenchymal Stromal Cell (MSC) Isolation and Induction of Acute and Replicative Senescence
No full textMesenchymal stromal cells (MSCs) are a heterogeneous population of non-hematopoietic adult stem cells derived from the embryonic mesoderm. They possess self-renewal and multipotent differentiation capabilities, allowing them to give rise to mesodermal cell types, such as osteoblasts, chondroblasts, and adipocytes, as well as non-mesodermal cells, including neuron-like cells and endothelial cells. MSCs play a vital role in maintaining homeostasis across various tissues by facilitating tissue repair, immune regulation, and inflammatory response balance. Initially identified in bone marrow, MSCs have since been found in multiple tissues, including muscle, adipose tissue, and dental pulp, and are characterized by specific surface markers and differentiation abilities. Aging induces cellular senescence, an irreversible growth arrest linked to various stressors, which has significant implications for regenerative medicine. While initially viewed as a protective mechanism against tumorigenesis, the accumulation of senescent cells, particularly in MSCs, leads to age-related diseases through the senescence-associated secretory phenotype (SASP). The onset of senescence in MSCs diminishes their therapeutic potential and contributes to homeostatic imbalance. Key drivers of MSC senescence include genetic damage, noncoding RNA, and mitochondrial dysfunction, among others. This study outlines the principal methodologies for the isolation and characterization of MSCs, alongside techniques to induce acute senescence via hydrogen peroxide or irradiation, as well as replicative senescence, to investigate senescence-related changes in vitro. Understanding the mechanisms of MSC senescence will provide critical insights into the molecular pathways of aging and pave way for advancements in cellular therapies targeting age-related diseases
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
- …
