159 research outputs found
Slow degrading Mg-based materials induce tumor cell dormancy on an osteosarcoma-fibroblast coculture model
No full textOsteosarcoma is one of the most common cancers in young adults and is commonly treated using surgery and chemotherapy. During the past years, these therapy approaches improved but failed to ameliorate the outcomes. Therefore, novel, targeted therapeutic approaches should be established to enhance treatment success while preserving patient's quality of life. Recent studies suggest the application of degradable magnesium (Mg) alloys as orthopedic implants bearing a potential antitumor activity. Here, we examined the influence of Mg-based materials on an osteosarcoma-fibroblast coculture. Both, Mg and Mg–6Ag did not lead to tumor cell apoptosis at low degradation rates. Instead, the Mg-based materials induced cellular dormancy in the cancer cells indicated by a lower number of Ki-67 positive cancer cells and a higher p38 expression. This dormancy-like state could be reversed by reseeding on non-degrading glass slides but could not be provoked by inhibition of the protein kinase R-like endoplasmic reticulum kinase. By investigating the influence of the disjunct surface-near effects of the Mg degradation on cell proliferation, an increased pH was found to be a main initiator of Mg degradation-dependent tumor cell proliferation inhibition
Characterisation of structure and aggregation processes of aquatic humic substances using small-angle scattering and X-ray microscopy
No full textAquatic humic substances (HS), an important part of the dissolved organic carbon in freshwater systems, are polyfunctional natural compounds with polydisperse structure showing strong aggregation/coagulation behaviour at high HS concentrations and in the presence of metal ions. In this study, small-angle neutron scattering (SANS), small-angle X-ray scattering (SAXS) and X-ray microscopy (XRM) were applied to characterise the structure and aggregation processes of HS in solution. In SAXS and XRM the high brilliant synchrotron radiation was used as X-ray source. Applying small-angle scattering, information about the size distribution and shape of aquatic HS was obtained. Spherical HS units were found which were stable in a wide concentration range in a kind of 'monomeric' state almost independent of pH and ionic strength. At higher concentrations they formed chain-like agglomerates or disordered HS structures. In studies on the coagulation behaviour of HS after addition of copper ions, a linear relationship between Cu2+ concentration and the formation of large disordered HS-Cu2+ agglomerates was obtained. By using X-ray microscopy, single 'huge' particles were found in older solutions and in solutions with high HS concentrations. Over a threshold Cu2+ concentration of approx. 300 mg/L, the formation of an extensive HS-Cu2+ network structure was observed within a few minutes. The presented structures show the ability of the methods used to characterise processes between diluted phase and suspended matter, which play an important role particularly in the region of phase interfaces
Optimizing an osteosarcoma-fibroblast coculture model to study antitumoral activity of magnesium-based biomaterials
No full textOsteosarcoma is among the most common cancers in young patients and is responsible for one-tenth of all cancer-related deaths in children. Surgery often leads to bone defects in excised tissue, while residual cancer cells may remain. Degradable magnesium alloys get increasing attention as orthopedic implants, and some studies have reported potential antitumor activity. However, most of the studies do not take the complex interaction between malignant cells and their surrounding stroma into account. Here, we applied a coculture model consisting of green fluorescent osteosarcoma cells and red fluorescent fibroblasts on extruded Mg and Mg–6Ag with a tailored degradation rate. In contrast to non-degrading Ti-based material, both Mg-based materials reduced relative tumor cell numbers. Comparing the influence of the material on a sparse and dense coculture, relative cell numbers were found to be statistically different, thus relevant, while magnesium alloy degradations were observed as cell density-independent. We concluded that the sparse coculture model is a suitable mechanistic system to further study the antitumor effects of Mg-based material
Experimental reports SANS-1 1998. Jahresbericht der SANS-1-Anlage 1998
No full textThe instrument SANS-1 at the Geesthacht Neutron Facility GeNF was used for scattering experiments in 1998 at 237 of 287 days of reactor operation. The utilisation was shared between the in-house R and D program (V 3.3.01.G.01) and user groups from different universities. These measurements were performed and analysed either by guest scientists or GKSS staff. The focus of the work in 1998 at the experiment SANS-1 was the structural investigation of hydrogen containing substances such as biological macromolecules (ribosomes), molecules which are important in the fields of environmental research (refractoric organic substances) and technical chemistry (surfactants, micelles). (orig.)SIGLEAvailable from TIB Hannover: RA 3251(99/E/12) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
Increased levels of sodium chloride directly increase osteoclastic differentiation and resorption in mice and men
No full textExperimental reports SANS-1 1999. Jahresbericht der SANS-1-Anlage 1999
No full textThe instrument SANS-1 at the Geesthacht Neutron Facility GeNF was used for scattering experiments in 1999 at 194 of 238 days of reactor operation. The utilisation was shared between the in-house R and D program (further information: http://wfs.home.pages.de target=NewWindow> http://wfs.home.pages.de ) and user groups from different universities. These measurements were performed and analysed either by guest scientists or GKSS staff. The focus of the work in 1999 at the experiment SANS-1 was the structural investigation of hydrogen containing substances such as biological macromolecules (ribosomes, protein-RNA-complexes), molecules which are important in the fields of environmental research (refractoric organic substances) and technical chemistry (surfactants, micelles). To a smaller extend also alloys were investigated. (orig.)SIGLEAvailable from TIB Hannover: RA 3251(2000/8) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
SANS-1 Experimental reports of 2000
No full textDas Instrument SANS-1 der Geesthachter Neutronenstreueinrichtung GeNF stand 2000 an 196 von 200 Reaktoroperationstagen (Volllast mit KNQ) zur Verfuegung. In dieser Zeit konnten Untersuchungen fuer das GKSS-eigene F and E-Programm (7.T1.00.G.03) sowie eine Reihe von Universitaeten oder Forschungszentren durchgefuehrt werden. Die Messungen der Universitaeten wurden entweder durch Gastwissenschaftler oder durch GKSS-Personal aufgenommen und analysiert. Der Schwerpunkt der Arbeiten im Jahr 2000 an der Kleinwinkelstreueinrichtung SANS-1 lag in dem Bereich der Strukturanalyse von wasserstoffhaltigen Substanzen wie Biomolekuelen (Ribosomen, Protein-RNA-Komplexe, Proteinloesungen, Glykolipide und Membranen), umweltrelevanten Stoffen (Huminstoffen) und Kolloidsystemen (Tenside, Mizellen). (orig.)The instrument SANS-1 at the Geesthacht neutron facility GeNF was used for scattering experiments in 2000 at 196 of 200 days of reactor and cold source operation. The utilisation was shared between the in-house R and D program and user groups from different universities and research centers. These measurements were performed and analysed either by guest scientists or GKSS staff. The focus of the work in 2000 at the experiment SANS-1 was the structural investigation of hydrogen containing substances such as biological macromolecules (ribosomes, protein-RNA-complexes, protein solutions, glycolipids and membranes), molecules which are important in the fields of environmental research (refractoric organic substances) and technical chemistry (surfactants, micelles). (orig.)SIGLEAvailable from TIB Hannover: RA 3251(2001/5) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
GeNF - experimental report 2003
No full textAt the Geesthacht Neutron Facility GeNF about 210 experiments were performed in 2003 by GKSS and by or for external users, partners or contractors. In most cases the measurements were performed and analysed in cooperation by the guest and by the GKSS staff or by the permanent external user group staff. The activities, which are based on a proposal procedure and on the in house R and D program, are reported in 76 contributions in the present annual experimental report for the year 2003. The contributions may contain one or also several combined experiments. During 2003 the GKSS research reactor FRG-1 achieved an operation time of 252 days at the full 5 MW reactor power providing a neutron flux of ca. 1,4 x 10"1"4 thermal neutrons / cm"2 s. The cold neutron source was available during the complete operation time. The focus of the in house R and D work at GeNF instruments was the characterisation of metal alloys, the analysis of stresses in welds and technical structures at ARES, FSS, DCD and SANS-2, the structural investigation of hydrogen containing substances such as polymers, colloids and biological macromolecules at SANS-1 as well as the characterisation of magnetic thin films at PNR and ROeDI. The reflectomer TOREMA was thoroughly upgraded to the instrument NeRo and now offers new measurement possibilities. In the appendices the progress of the project REFSANS at FRM-II is reported as well as the experimental activities of the newly installed GKSS outstation HARWI-II at DESY. (orig.)Available from TIB Hannover: RA 3251(04/1) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman
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