1,721,459 research outputs found
Cytokines: from gut inflammation to colorectal cancer
No full textColorectal cancer represents a life-threatening complication of inflammatory bowel diseases. Statistics indicate that the risk to develop colorectal cancer is higher in patients affected by ulcerative colitis and to a lesser extent by Crohn's disease and that such a risk is directly proportional to the number of years of active disease. These observations suggest that chronic inflammation may substantially contribute to cancer development. However the molecular mechanisms underlying this process have been only recently started to be clarified. Indeed from the initial concept that the release of free radicals during inflammation might induce the accumulation of genetic mutations thus leading to the onset of dysplastic cells, it is now becoming clear that the large amount of cytokines and growth factors released during inflammation by immune and non immune cells may influence the carcinogenesis process. IL-6 and IL-23, cytokines which play key roles in the induction and maintenance of gut inflammation during IBDs, have been recently shown to influence the development and growth of colitis associated colorectal cancer. Moreover, the activation of the nuclear factor k B (NFkB), a transcription factor activated by several cytokines released during inflammation and responsible for many of their proinflammatory effects, have been shown to promote the growth of the colon tumors in experimental models
From inflammation to colitis-associated colorectal cancer in inflammatory bowel disease: Pathogenesis and impact of current therapies
No full textThe risk of colorectal cancer (CRC) is higher in patients with inflammatory bowel disease (IBD). Population-based data from patients with ulcerative colitis (UC) estimate that the risk of CRC is approximately 2- to 3-fold that of the general population; patients with Crohn's disease appear to have a similar increased risk. However, the true extent of colitis-associated cancer (CAC) in undertreated IBD is unclear. Data suggest that the size (i.e., severity and extent) and persistence of the inflammatory process is largely responsible for the development of CRC in IBD. As patients with IBD and CRC have a worse prognosis than those without a history of IBD, the impact of current therapies for IBD on CAC is of importance. Chronic inflammation of the gut has been shown to increase the risk of developing CAC in both UC and CD. Therefore, control of inflammation is pivotal to the prevention of CAC. This review presents an overview of the current knowledge of CAC in IBD patients, focusing on the role of inflammation in the pathogenesis of CAC and the potential for IBD drugs to interfere with the process of carcinogenesis by reducing the inflammatory process or by modulating pathways directly involved in carcinogenesis
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
A method to design biomimetic scaffolds for bone tissue engineering based on Voronoi lattices
Full text linkIn regenerative medicine, 3D scaffolds are used to sustain the regeneration of tissues in removed or damaged parts of the human body. As such practices are being widely experimented in clinical applications, the design, the materials and the manufacturing process to obtain efficient 3D biocompatible lattices are being significantly investigated. Nevertheless, most of the proposed designs are based on regular 3D shapes obtained from the repetition of unit cells disposed in a three-dimensional array. This approach does not exploit the whole potential of computer-aided design tools coupled with manufacturing capabilities for freeform shapes. In this paper, we propose a method to model biomimetic lattices controlling the porosity and the pores size of scaffolds to be integrated with the anatomical shape of the defect. The method has been implemented in bone tissue case study and implements a generative design approach based on Voronoi diagrams
The action of high and steep mountains on baroclinic instability and Alpine cyclogenesis
No full textThe modification induced on unstable baroclinic waves by high and steep bottom obstacles of limited horizontal extent is studied in some, mathematically tractable, limiting cases (obstacles with vertical lateral walls blocking the horizontal motion of the fluid). The model atmosphere is assumed quasi-geostrophic and the stability problem is dealt with in the two-level approximation. The results of such analysis show that the action of the obstacle can extend to the entire baroclinic wave unless strongly non-geostrophic effects, relaxing the “stiffness” of the quasi-geostrophic flow near the obstacle, are postulated. The weaknesses of this representation with respect to the problem of Alpine lee cyclogenesis are discussed
Un approccio con elementi di contorno per l'interazione dinamica di strutture di fondazione attraverso il suolo
No full textViene presentato un approccio con il metodo degli elementi di contorno allo studio di problemi di interazione dinamica di fondazioni nastriformi col suolo, rappresentato come un semispazio elastico. Il problema è formulato nel dominio delle frequenze con riferimento ad un solido (semispazio) con contorno rettilineo a tratti, in stato piano di deformazione. Su ogni elemento di contorno lo spostamento e lo sforzo vengono rappresentati con polinomi di Lagrange. Viene proposta una procedura per la valutazione diretta degli integrali fortemente singolari, basata su una decomposizione della soluzione fondamentale in una parte singolare ed in una regolare. In tal modo è possibile evitare sia il problema della valutazione dei termini divergenti in punti di Gauss prossimi al nodo di collocazione sia il problema della adozione di espressioni semplificate per le funzioni di Bessel che compaiono nell’espressione dello sforzo della soluzione fondamentale. Il metodo proposto è applicato all'analisi della risposta dinamica nel caso di una fondazione rigida nastriforme isolata e di due fondazioni tra loro interagenti attraverso il suolo
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
Angiogenesis, immune system and growth factors: new targets in colorectal cancer therapy
No full textColorectal cancer is the second most common malignant human neoplasia. Over recent years, many efforts have been performed in order to develop and improve therapeutic protocols, and many advances have been accomplished in both the field of adjuvant and palliative therapy. Most of the chemotherapic agents currently used in the clinical setting are the products of decades of research aimed at inhibiting the uncontrolled growth of dysplastic cells. However, new frontiers in this field have recently been opened, with the identification of key molecules involved in physiologic mechanisms that are of fundamental importance for cancer development and progression. Tumor-induced angiogenesis, the cancer-immune system crosstalk and the effect of growth factors on dysplastic cells represent new fields of investigation for anticancer therapy
New players in the cytokine orchestra of inflammatory bowel disease
No full textIn both Crohn's disease (CD) and ulcerative colitis, the pathologic process is almost certainly driven by an aberrant local immune response directed against normal components of the bacterial microflora. Mucosal immune cells interact with nonimmune cells such as epithelial cells and fibroblasts to promote tissue damage; cytokines are essential mediators of this cross talk. Accumulating evidence now suggests that interleukin-21 (IL-21), the newest member of the common gamma-chain-dependent cytokine family, is a key component of the inflammatory cascade. IL-21 is highly produced by activated CD4+ lymphocytes in the inflamed gut of patients with CD, where it contributes to sustaining the ongoing Th1 inflammation. IL-21 also increases the secretion of extracellular matrix-degrading enzymes by fibroblasts and of MIP-3α by epithelial cells. Two other cytokines, IL-27 and IL-32, may also be important in the inflammatory pathways that operate in IBD
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