1,720,959 research outputs found
Novel therapeutic targets in osteoarthritis: Narrative review on knock-out genes involved in disease development in mouse animal models
No full textOsteoarthritis (OA) can affect every joint, especially the knee. Given the complexity of this pathology, OA is difficult to treat with current therapies, which only relieve pain and inflammation and are not capable of restoring tissues once OA has started. Currently, researchers focus on finding a therapeutic strategy that may help to arrest disease progression.The present narrative review gives an overview of the genes involved in the development and progression of OA, assessing in vivo studies performed in knock-out mice affected by OA, to suggest new therapeutic strategies. The article search was performed on the PubMed database and www.webofknowledge.com website with the following keywords: "knee osteoarthritis" AND "knockout mice". The included studies were in English and published from 2005 to 2015. Additional papers were found within the references of the selected articles. In the 55 analyzed in vivo studies, genes mainly affected chondrocyte homeostasis, inflammatory processes, extracellular matrix and the relationship between obesity and OA. Genes are defined as inducing, preventing and not influencing OA. This review shows that joint homeostasis depends on a variety of genetic factors, and preventing or restoring the loss of a gene encoding for protective proteins, or inhibiting the expression of proteins that induce OA, might be a potential therapeutic approach. However, conclusions cannot be drawn because of the wide variability concerning the technique used for OA induction, the role of the genes, the method for tissue evaluations and the lack of assessments of all joint tissues
Photobiomodulation with low-level diode laser promotes osteoblast migration in an in vitro micro wound model
No full textLaser photobiomodulation can improve bone healing, but well-defined treatment parameters are lacking. Saos-2 human osteoblast-like cells were subjected to an in vitro scratch-wound healing assay and irradiated by a 915-nm gallium-aluminum-arsenide diode laser for 0, 48, 96, and 144 s using doses of, respectively, 0, 5, 10, and 15 J/cm2. Wound area was measured after 4, 24, 48, and 72 h. Cell viability, DNA content, gene expression, and release of bone-related proteins were evaluated after 24, 48, and 72 h. Laser significantly improved wound healing compared with nonirradiated controls. Cells treated with laser doses of 5 and 10 J/cm2 reached wound closure after 72 h, followed by 15 J/cm2 after 96 h. With the cell proliferation inhibitor Mitomycin C, the doses of 10 and 15 J/cm2 maintained an improved wound healing compared with controls. Laser increased collagen type 1 gene expression with higher doses inducing a longer-lasting effect, whereas transforming growth factor-beta 1 showed comparable or decreased levels in irradiated versus nonirradiated groups, with no effect on protein release. This study demonstrated that laser photobiomodulation at 915 nm promoted wound healing mainly through stimulation of cell migration and collagen deposition by osteoblasts
A Human 3D In Vitro Model to Assess the Relationship Between Osteoporosis and Dissemination to Bone of Breast Cancer Tumor Cells
No full textDespite consistent improvements in diagnostic and therapeutic strategies for breast cancer, up to 40% of patients will develop bone metastases. To reduce the morbidity and complications related with bone metastases, it is imperative to reduce their etiological factors. Osteoporosis, being characterized by a sudden estrogen deficiency, may provide a favorable condition for bone metastasis. This work, using a humanized 3D in vitro model, aims at evaluating the relationship between osteoporosis and breast cancer-derived bone metastases. Bone tissue discarded from total hip replacement surgery of healthy and osteoporotic patients was cultured in a rolling apparatus system in hypoxic environment. Protein levels (i.e., vascular endothelial growth factor (VEGF), VEGF receptor 1, VEGF receptor 2, interleukin (IL)-6, IL-1β, IL-8 IL-10, tumor necrosis factor α (TNF-α), osteoprotegerin (OPG), receptor activator for nuclear factor KB ligand (RANKL)) and histological and immunohistochemical (i.e., cytokeratin 8 and 18) analyses showed a noticeable specificity of breast cancer cells for the colonization of osteoporotic bone. These data are the first to demonstrate that using humanized 3D in vitro systems, which individually model the pre- and postmenopausal bone microenvironment, it is possible to recognize major differences in tumor growth and colonization between healthy and osteoporotic status. Thus, this system might help to develop a shared system between basic and clinical sciences where a personalized diagnosis is associated to a therapeutic strategy designed for a single patient: a model able to achieve a translational research approach in the clinical setting, which may lead to the application and dissemination of personalized medicine. J. Cell. Physiol. 232: 1826–1834, 2017. © 2016 Wiley Periodicals, Inc
Evaluation of RNA from human trabecular bone and identification of stable reference genes
No full textThe isolation of good quality RNA from tissues is an essential prerequisite for gene expression analysis to study pathophysiological processes. This study evaluated the RNA isolated from human trabecular bone and defined a set of stable reference genes. After pulverization, RNA was extracted with a phenol/chloroform method and then purified using silica columns. The A260/280 ratio, A260/230 ratio, RIN, and ribosomal ratio were measured to evaluate RNA quality and integrity. Moreover, the expression of six candidates was analyzed by qPCR and different algorithms were applied to assess reference gene stability. A good purity and quality of RNA was achieved according to A260/280 and A260/230 ratios, and RIN values. TBP, YWHAZ, and PGK1 were the most stable reference genes that should be used for gene expression analysis. In summary, the method proposed is suitable for gene expression evaluation in human bone and a set of reliable reference genes has been identified
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
Increased Chondrogenic Potential of Mesenchymal Cells From Adipose Tissue Versus Bone Marrow-Derived Cells in Osteoarthritic In Vitro Models
No full textPrimarily, to compare the behavior of human mesenchymal stem cells (MSCs) derived from bone marrow (hBMSCs) and adipose tissue (hADSCs) in an osteoarthritic (OA) microenvironment; secondly, to investigate the reaction of these cell types in two alternative in vitro culture systems, obtained by using TNFα and/or IL1β as inflammation mediators, or by using synovial fluid harvested by OA patients (OSF) to simulate the complex inflamed knee microenvironment. 3D micromass cultures of hBMSCs or hADSCs were grown in chondrogenic medium (CTR), in the presence of TNFα and/or IL1β, or synovial fluid from OA patients. After 1 month of culture, the chondrogenic differentiation of micromasses was evaluated by gene expression, matrix composition, and organization. Both hMSCs types formed mature micromasses in CTR, but a better response of hADSCs to the inflammatory environment was documented by micromass area and Bern score evaluations. The addition of OSF elicited a milder reaction than with TNFα and/or IL1β by both cell types, probably due to the presence of both catabolic and protective factors. In particular, SOX9 and ACAN gene expression and GAG synthesis were more abundant in hADSCs than hBMSCs when cultured in OSF. The expression of MMP1 was increased for both hMSCs in inflammatory conditions, but in particular by hBMSCs. hADSCs showed an increased chondrogenic potential in inflammatory culture systems, suggesting a better response of hADSCs in the OA environment, thus underlining the importance of appropriate in vitro models to study MSCs and potential advantages of using these cells for future clinical applications. J. Cell. Physiol. 9999: 1-11, 2016. © 2016 Wiley Periodicals, Inc
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
- …
