157 research outputs found
Hematopoietic growth factors and tumor angiogenesis
No full textAngiogenesis is regulated by numerous "classic" factors such as vascular endothelial growth factor (VEGF) and many other endogenous "non-classic"peptides, including erythropoietin (Epo), and granulocyte-/granulocyte macrophage colony stimulating factor (G-/GM-CSF). The latter play an important regulatory role in angiogenesis, especially under pathological conditions and constitute a crosslink between angiogenesis and hematopoiesis. This article reviews studies on the ability of hematopoietic cytokines to affect several endothelial cell functions in tumor angiogenesis. These findings in all these studies support the hypothesis formulated at the beginning of this century that a common ancestral cell, the hemangioblast, gives rise to cells of both the endothelial and the hematopoietic lineages
Is a Semantic Web Agent a Knowledge-Savvy Agent?
No full textThe issue of knowledge sharing has permeated the field of distributed AI and in particular, its successor, multiagent systems. Through the years, many research and engineering efforts have tackled the problem of encoding and sharing knowledge without the need for a single, centralized knowledge base. However, the emergence of modern computing paradigms such as distributed, open systems have highlighted the importance of sharing distributed and heterogeneous knowledge at a larger scale—possibly at the scale of the Internet. The very characteristics that define the Semantic Web—that is, dynamic, distributed, incomplete, and uncertain knowledge—suggest the need for autonomy in distributed software systems. Semantic Web research promises more than mere management of ontologies and data through the definition of machine-understandable languages. The openness and decentralization introduced by multiagent systems and service-oriented architectures give rise to new knowledge management models, for which we can’t make a priori assumptions about the type of interaction an agent or a service may be engaged in, and likewise about the message protocols and vocabulary used. We therefore discuss the problem of knowledge management for open multi-agent systems, and highlight a number of challenges relating to the exchange and evolution of knowledge in open environments, which pertinent to both the Semantic Web and Multi Agent System communities alike
A revisited concept. Tumors: Wounds that do not heal
No full textIn 1986, Harold F. Dvorak, Professor of Pathology at Harvard Medical School Boston, published an essay in the New England Journal of Medicine entitled "Tumors: Wounds that do not heal" pointed out that similarities exist between tumor stroma generation and wound healing. Cancers share many features in common with tissue regeneration, including immune response, cell proliferation, cell migration, tissue remodeling, and cell death. In this review article, we analyze the importance and the limits of this concept, which confirm the close relationship between two apparently different biological processes
Bone niches, hematopoietic stem cells, and vessel formation
No full textBone marrow (BM) is a source of hematopoietic stem cells (HSCs). HSCs are localized in both the endosteum, in the so-called endosteal niche, and close to thin-walled and fenestrated sinusoidal vessel in the center of BM, in the so-called vascular niche. HSCs give rise to all types of mature blood cells through a process finely controlled by numerous signals emerging from the bone marrow niches where HSCs reside. This review will focus on the description of the role of BM niches in the control of the fate of HSCs and will also highlight the role of the BM niches in the regulation of vasculogenesis and angiogenesis. Moreover, alterations of the signals in niche microenvironment are involved in many aspects of tumor progression and vascularization and further knowledge could provide the basis for the development of new therapeutic strategies
The chick embryo chorioallantoic membrane as an in vivo experimental model to study human neuroblastoma
No full textThe chick embryo chorioallantoic membrane (CAM) has long been a favored system for the study of tumor angiogenesis because at the stage of development when generally tumor grafts are placed (6-10 days of incubation), the chick's immunocompetent system is not fully developed and the conditions for rejection have not yet been established. All studies for mammalian neoplasms, including neuroblastoma, have used tumor cell lines, tumor bioptic specimens, cell suspensions derived from tumors, and mouse tumor xenografts bioptic specimens. CAM can also be used to study the effects of antiangiogenic molecules on tumor cell suspensions of tumor bioptic specimens. This review article summarizes and discusses the literature data on the use of the CAM as an in vivo experimental model to study human neuroblastoma
Giulio Gabbiani and the discovery of myofibroblasts
No full textMyofibroblasts, specialized fibroblasts expressing the protein alpha-smooth muscle actin, are instrumental in wound contraction during normal wound healing. Tissue shortening is then stabilized by the synthesis of extracellular matrix, collagen in particular. Alpha-smooth muscle actin within myofibroblasts becomes organized in filamentous bundles, called stress fibers, that allow the retractile movement producing wound contraction. During hypertrophic scarring, skin deformations depend on the inappropriate action of these stress fibers that for unknown reasons persist even after the epithelialization of the wound. This historical review article is dedicated to the reconstruction of the discovery of this cell by the Italian scientist Giulio Gabbiani
Mast Cells and Angiogenesis in Human Plasma Cell Malignancies
No full textBone marrow angiogenesis plays an important role in the pathogenesis and progression of hematological malignancies. It is well known that tumor microenvironment promotes tumor angiogenesis, proliferation, invasion, and metastasis, and also mediates mechanisms of therapeutic resistance. An increased number of mast cells has been demonstrated in angiogenesis associated with hematological tumors. In this review we focused on the role of mast cells in angiogenesis in human plasma cell malignancies. In this context, mast cells might act as a new target for the adjuvant treatment of these tumors through the selective inhibition of angiogenesis, tissue remodeling and tumor-promoting molecules, permitting the secretion of cytotoxic cytokines and preventing mast cell-mediated immune suppression
Update in TIGIT Immune-Checkpoint Role in Cancer
No full textThe in-depth characterization of cross-talk between tumor cells and T cells in solid and hematological malignancies will have to be considered to develop new therapeutical strategies concerning the reactivation and maintenance of patient-specific antitumor responses within the patient tumor microenvironment. Activation of immune cells depends on a delicate balance between activating and inhibitory signals mediated by different receptors. T cell immunoreceptor with immunoglobulin and ITIM domain (TIGIT) is an inhibitory receptor expressed by regulatory T cells (Tregs), activated T cells, and natural killer (NK) cells. TIGIT pathway regulates T cell-mediated tumor recognition in vivo and in vitro and represents an exciting target for checkpoint blockade immunotherapy. TIGIT blockade as monotherapy or in combination with other inhibitor receptors or drugs is emerging in clinical trials in patients with cancer. The purpose of this review is to update the role of TIGIT in cancer progression, looking at TIGIT pathways that are often upregulated in immune cells and at possible therapeutic strategies to avoid tumor aggressiveness, drug resistance, and treatment side effects. However, in the first part, we overviewed the role of immune checkpoints in immunoediting, the TIGIT structure and ligands, and summarized the key immune cells that express TIGIT
The Role of Bone Stem Cell Niches in Bone Metastasis
No full textIn post-natal life, stem cells contribute to the preservation of many tissues. In adults, stem cells remain localized, in particular, specialized microanatomical areas named as niches, which are crucial in the control of stem cell quiescence and activity through the production of many regulatory signals. Bone physiologically includes both the endosteal niche and the vascular niche, which are involved in the attraction, retention and release of the residing stem cells during the formation of new vessels as well as in the control of the differentiation of bone-forming osteoblasts and bone-resorbing osteoclasts. In tumors, cancer cells are able to take control of the niches to support all the stages of the tumorigenesis, transforming them in the so-called pre-metastatic and metastatic niches. Hence, there is emerging importance of the interactions between cancer cells, bone cells and niches in driving metastatic progression. This review article summarizes the literature data concerning the role of bone vascular and endosteal niches in the regulation of bone metastasis, focusing on their cellular and molecular interactions and the potential therapeutic approaches
Thermal process of fluff: Preliminary tests on a full-scale treatment plant
No full textUntil only recently fluff has been largely disposed of in controlled landfill sites. However, in Europe environmental regulations, including the EU Landfill Directive 1999/31/EC and ELV (End of Life Vehicle) Directive 2000/53/EC, have dramatically increased the pressure on all stakeholders to develop alternative solutions. As increasingly stringent legislation forces Shredder Residues (SR) to be diverted from landfilling, newly developed technologies will be in a position to compete for the market value of disposing of the waste. However, the fluff waste stream is so variable that it cannot be automatically assumed that processes developed for one type of fluff will prove to be suitable for other fluff streams. This situation has contributed towards convincing stakeholders to withhold investment funds or delay taking decisions as to how best to proceed: as a consequence, very few technologies have been fully developed on a commercial basis. It is of particular interest therefore that commercial alternatives to be used in dealing with this complex waste stream should be identified. The present paper illustrates the findings of a full-scale thermal treatment performed on SR samples obtained from various shredding plants. The outcome of the study provides an important contribution towards assessing the feasibility and reliability of the process, thus constituting a basic prerequisite for process performance evaluation. The full-scale plant, designed for the thermo-valorization of tyres, was purpose-modified to allow for fluff combustion. Three different fluff compositions (car fluff with different percentage of shredding, whites and 100% car fluff) were taken into consideration. Both the raw samples and solid products were thoroughly characterized. Combustion emissions were continuously analyzed during the test period, alternatively operating for tyre and fluff combustion. Classification of combustion residues for landfill disposal was carried out indicating only 2% (ashes) as hazardous waste. Preliminary results, obtained from a unsophisticated thermodynamic analysis of the process, indicated a value of 0.61 for energy efficiency parameter calculated in accordance with the Directive 2008/98/EC. To conclude, the thermal treatment investigated may be deemed an appropriate technique for use in managing fluff. Indeed, values obtained for all organic and inorganic contaminants released into the atmosphere were lower than legal limits prescribed, and a significant energy content was recovered from waste fractions. (C) 2010 Elsevier Ltd. All rights reserved
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