94 research outputs found
The accuracy analysis of lidar-derived elevation data for the geometric description of the cross-sections of a riverbed
The work stems from a joint study between the Laboratory ASTRO (Department of Civil and Industrial Engineering - University of Pisa), the municipality of Pisa and the province of Arezzo on the advanced analysis and use of digital elevation data. Besides, it is framed in the research carried on by ASTRO about the definition of the priority informative layers for emergency management in the territory, as of PRIN 2008. Specifically, this work is in continuity with other already published results concerning rigorous accuracy checks of LIDAR data and testing of the procedures to transform raw data in formats consistent with the CTR and survey data. The analysis of sections of riverbed, obtained by interpolation DTMs featuring different grid density with those detected topographically, is presented. Validation by differential GNSS methodology of the DTMs used showed a good overall quality of the model for open, low-sloping areas. Analysis of the sections, however, has shown that the representation of small or high-sloping (ditches, embankments) morphological elements requires a high point density such as in laser scanner surveys, and a small mesh size of the grid. In addition, the correct representation of riverside structures is often hindered by the presence of thick vegetation and poor raw LIDAR data filtering
Receptor activator of nuclear factor-kappa B ligand (RANKL) directly modulates the gene expression profile of RANK-positive Saos-2 human osteosarcoma cells
Receptor activator of nuclear factor κB (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) are the key regulators of bone metabolism. Recent findings demonstrated a crucial role of RANK in several bone-associated tumors. Indeed, we have recently demonstrated functional RANK expression both in a mouse and several human osteosarcoma cell lines. However, RANKL effects on osteosarcoma cells remain to be determined. In this study, we determined RANKL effects on RANK-positive Saos-2 human osteosarcoma cells. cDNA microarray and quantitative RT-PCR analyses clearly demonstrated that RANK-positive osteosarcoma cells were the target of RANKL as well as osteoclasts/osteoclast precursors. Thus, we present for the first time that RANKL can directly and significantly modulate gene expression of RANK-expressing Saos-2 cells. RANKL-modulated genes included genes that were implicated in protein metabolism, nucleic acid metabolism, intracellular transport, cytoskeleton organization and biogenesis, apoptosis and signaling cascade. Our results strengthen the involvement of the RANK/RANKL/OPG axis in osteosarcoma biology and capability to identify novel therapeutic approaches targeting RANK-positive osteosarcomas
L-MTP-PE and zoledronic acid combination in osteosarcoma: pre-clinical evidence of positive therapeutic combination for clinical transfer
Osteosarcoma, the most frequent malignant primary bone tumor in pediatric patients is characterized by
osteolysis promoting tumor growth. Lung metastasis is the major bad prognosis factor of this disease. Zoledronic
Acid (ZA), a potent inhibitor of bone resorption is currently evaluated in phase III randomized studies in Europe for
the treatment of osteosarcoma and Ewing sarcoma. The beneicial effect of the liposomal form of Muramyl-TriPeptide-Phosphatidyl
Ethanolamine (L-mifamurtide, MEPACT®), an activator of macrophage populations has been demonstrated
to eradicate lung metastatic foci in osteosarcoma. The objective of this study was to evaluate the potential
therapeutic beneit and the safety of the ZA and L-mifamurtide combination in preclinical models of osteosarcoma,
as a prerequisite before translation to patients. The effects of ZA (100 µg/kg) and L-mifamurtide (1 mg/kg) were
investigated in vivo in xenogeneic and syngeneic mice models of osteosarcoma, at clinical (tumor proliferation,
spontaneous lung metastases development), radiological (bone microarchitecture by microCT analysis), biological
and histological levels. No interference between the two drugs could be observed on ZA-induced bone protection
and on L-mifamurtide-induced inhibition of lung metastasis development. Unexpectedly, ZA and L-mifamurtide association
induced an additional and in some cases synergistic inhibition of primary tumor progression. L-mifamurtide
has no effect on tumor proliferation in vitro or in vivo, and macrophage population was not affected at the tumor
site whatever the treatment. This study evidenced for the irst time a signiicant inhibition of primary osteosarcoma
progression when both drugs are combined. This result constitutes a irst proof-of-principle for clinical application in osteosarcoma patients
Tc-99m-NTP 15-5 assessment of the early therapeutic response of chondrosarcoma to zoledronic acid in the Swarm rat orthotopic model
Background: Since proteoglycans (PGs) appear as key partners in chondrosarcoma biology, PG-targeted imaging using the radiotracer 99mTc-N-(triethylammonium)-3-propyl-[15]ane-N5 (99mTc-NTP 15-5) developed by our group was previously demonstrated to be a good single-photon emission computed tomography tracer for cartilage neoplasms. We therefore initiated this new preclinical study to evaluate the relevance of 99mTc-NTP 15-5 imaging for the in vivo monitoring and quantitative assessment of chondrosarcoma response to zoledronic acid (ZOL) in the Swarm rat orthotopic model.
Findings: Rats bearing chondrosarcoma in the orthotopic paratibial location were treated by ZOL (100 μg/kg, subcutaneously) or phosphate-buffered saline, twice a week, from day 4 to day 48 post-tumor implantation. 99mTc-NTP 15-5 imaging was performed at regular intervals with the target-to-background ratio (TBR) determined. Tumor volume was monitored using a calliper, and histology was performed at the end of the study. From day 11 to day 48, mean TBR values ranged from 1.7 ± 0.6 to 2.3 ± 0.6 in ZOL-treated rats and from 2.1 ± 1.0 to 4.9 ± 0.9 in controls. Tumor growth inhibition was evidenced using a calliper from day 24 and associated to a decrease in PG content in treated tumor tissues (confirmed by histology).
Conclusions: This work demonstrated two proofs of concept: (1) biphosphonate therapy could be a promising therapeutic approach for chondrosarcoma; (2) 99mTc-NTP 15-5 is expected to offer a novel imaging modality for the in vivo evaluation of the extracellular matrix features of chondrosarcoma, which could be useful for the follow-up and quantitative assessment of proteoglycan ‘downregulation’ associated to the response to therapeutic attempts
Research ethics in an unethical world: the politics and morality of engaged research
This article explores ethical dilemmas in researching the world of work. Recent contributions to WES have highlighted challenges for engaged research. Based on the emancipatory epistemologies of Bourdieu, Gramsci and Burawoy, the authors examine moral challenges in workplace fieldwork, question the assumptions of mainstream ethics discourses and seek to identify an alternative approach. Instead of an ethics premised on a priori, universal precepts that treasures academic neutrality, this article recognises a morality that responds to the social context of research with participation and commitment. The reflection in this study is based on fieldwork conducted in the former Soviet Union. Transformation societies present challenges to participatory ethnography but simultaneously provide considerable opportunities for developing an ethics of truth. An approach that can guide engaged researchers through social conflict’s ‘messy’ reality should hinge on loyalty to the emancipation struggles of those engaged in it
Osteoprotegerin: multiple partners for multiple functions.
Osteoprotegerin (OPG) is an essential secreted protein in bone turnover due to its role as a decoy receptor for the Receptor Activator of Nuclear Factor-kB ligand (RANKL) in the osteoclasts, thus inhibiting their differentiation. However, there are additional ligands of OPG that confer various biological functions. OPG can promote cell survival, cell proliferation and facilitates migration by binding TNF-related apoptosis inducing ligand (TRAIL), glycosaminoglycans or proteoglycans. A large number of in vitro, pre-clinical and clinical studies provide evidences of OPG involvement in vascular, bone, immune and tumor biology. This review describes an overview of the different OPG ligands regulating its biological functions
Drugs targeting the bone microenvironment: new therapeutic tools in Ewing's sarcoma?
Introduction: Ewing's sarcoma (ES) is the second most frequent malignant primary bone tumour in children, adolescents and young adults. The overall survival is 60 – 70% at 5 years but still very poor for patients with metastases, disease relapse or for those not responding to chemotherapy. For these high risk patients, new therapeutic approaches are needed beyond conventional therapies (chemotherapy, surgery and radiation) such as targeted therapies.
Areas covered: Transcriptomic and genomic analyses in ES have revealed alterations in genes that control signalling pathways involved in many other cancer types. To set up more specific approaches, it is reasonable to think that the particular microenvironment of these bone tumours is essential for their initiation and progression, including in ES. To support this hypothesis, preclinical studies using drugs targeting bone cells (bisphosphonate zoledronate, anti-receptor activator of NF-κB ligand strategies) showed promising results in animal models. This review will discuss the new targeted therapeutic options in ES, focusing more particularly on the ones modulating the bone microenvironment.
Expert opinion: Targeting the microenvironment represents a new option for patients with ES. The proof-of-concept has been demonstrated in preclinical studies using relevant animal models, especially for zoledronate, which induced a strong inhibition of tumour progression in an orthotopic bone model
Report from the 4th European Bone Sarcoma Networking meeting: focus on osteosarcoma
Abstract
This report summarizes the proceedings of the 4th European Bone Sarcoma Networking Meeting, held in London, England, on 21 June 2017. The meeting brought together scientific and clinical researchers and representatives from sarcoma charities from 19 countries representing five networks across Europe, to present and discuss new developments on bone sarcoma. In view of the challenges is poses, the meeting focussed primarily on osteosarcoma with presentations on developments in our understanding of osteosarcoma genetics and immunology as well as results from preclinical investigations and discussion of recent and ongoing clinical trials. These include studies examining the efficacy of multi-targeted tyrosine kinase inhibitors and checkpoint inhibitors, as well as those with molecular profiling to stratify patients for specific therapies. Discussion was centred on generation of new hypotheses for collaborative biological and clinical investigations, the ultimate goal being to improve therapy and outcome in patients with bone sarcomas
TThe ENCCA-WP7/EuroSarc/EEC/PROVABES/EURAMOS 3rd European Bone Sarcoma Networking Meeting/Joint Workshop of EU Bone Sarcoma Translational Research Networks; Vienna, Austria, September 24–25, 2015. Workshop Report
This report summarizes the results of the 3rd Joint ENCCA-WP7, EuroSarc, EEC, PROVABES, and EURAMOS European Bone Sarcoma Network Meeting, which was held at the Children's Cancer Research Institute in Vienna, Austria on September 24-25, 2015. The joint bone sarcoma network meetings bring together European bone sarcoma researchers to present and discuss current knowledge on bone sarcoma biology, genetics, immunology, as well as results from preclinical investigations and clinical trials, to generate novel hypotheses for collaborative biological and clinical investigations. The ultimate goal is to further improve therapy and outcome in patients with bone sarcomas
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