403 research outputs found
Nationales Krebsprogramm für die Schweiz 2011-2015
No full textAuteurs travaillant au CHUV: Doris Schopper, Roger Stupp, Franz Stiefel, Maya Shah
Abstract 1504: Tumor-treating fields (TTFields) interfere with biological key properties of glioma cells in vitro
No full textAbstract
Tumor-treating fields (TTFields) are low amplitude alternating electric fields which are supposed to exert anti-tumor effects by targeting dividing tumor cells while sparing cells in the brain not undergoing cell division. Although this novel therapeutic approach has shown encouraging results in phase III trials in glioblastoma, its biological effects on tumor cells have only been poorly understood.
Here, we investigated the effects of TTFields on glioma cells in vitro using the inovitroTM system that allows the application of TTFields to cell cultures. Exposure to TTFields potently induce autophagy and necroptosis and interfere with the migration and invasion of long-term glioma cell lines, but also of glioma-initiating. The combination of TTFields with irradiation or temozolomide (TMZ) reduced viability and clonogenic survival in an additive or synergistic manner. Further studies suggest that the O6-methyl-guanine DNA methyltransferase (MGMT) status does not influence the efficacy of TTFields and TMZ-resistant glioma cells remain responsive to TTFields application, thus making TTFields particularly attractive for the majority of glioblastoma patients with tumors that are unlikely to benefit from TMZ treatment.
In summary, these findings demonstrate that the application of TTFields may interfere with various biological key properties of glioma cells and may allow for a more detailed clinical evaluation of TTFields beyond the clinical data available so far.
Citation Format: Manuela Silginer, Michael Weller, Roger Stupp, Patrick Roth. Tumor-treating fields (TTFields) interfere with biological key properties of glioma cells in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1504. doi:10.1158/1538-7445.AM2017-1504</jats:p
Synthesis and characterization of novel polymer-ceramic nanocomposites: Organoceramics
No full textThis manuscript describes the synthesis and characterization of novel polymer-ceramic nanocomposites (organoceramics) based on various water soluble polymers and calcium aluminate hydrates. Synthesis of these materials involves the aqueous precipitation of the inorganic crystals in the presence of polymer. The presence of polymer during crystallization often leads to changes in particle morphology, and in some cases intercalation.The organoceramics based on poly(vinyl alcohol) (PVA) and \rm CaO{\cdot} Al\sb2O\sb3{\cdot} 10H\sb2O (CAH\sb{10}) were found to exhibit retarded phase transformation kinetics and unique particle morphologies. Intercalation of PVA between layers of \rm\lbrack Ca\sb2Al(OH)\sb6\rbrack\sp+\lbrack(OH){\cdot} 3H\sb2O\rbrack\sp- occurred during crystal growth, resulting in an organoceramic containing up to 40% polymer by weight. Polymer intercalation resulted in an expression of the interlayer by approximately 10 A, consistent with the formation of a double layer of PVA chains across each interlayer. Thermal degradation of the inorganic and polymeric components of the organoceramic occurred at higher temperatures than the individual materials. Compressive strength of PVA organoceramic powder compacts was significantly higher than that of \rm\lbrack Ca\sb2Al(OH)\sb6\rbrack\sp+\lbrack(OH){\cdot} 3H\sb2O\rbrack\sp- compacts, possibly reflecting substantial differences in particle morphologies.U of I OnlyETDs are only available to UIUC Users without author permissio
Synthesis and characterization of novel polymer-ceramic nanocomposites: Organoceramics
No full textThis manuscript describes the synthesis and characterization of novel polymer-ceramic nanocomposites (organoceramics) based on various water soluble polymers and calcium aluminate hydrates. Synthesis of these materials involves the aqueous precipitation of the inorganic crystals in the presence of polymer. The presence of polymer during crystallization often leads to changes in particle morphology, and in some cases intercalation.The organoceramics based on poly(vinyl alcohol) (PVA) and \rm CaO{\cdot} Al\sb2O\sb3{\cdot} 10H\sb2O (CAH\sb{10}) were found to exhibit retarded phase transformation kinetics and unique particle morphologies. Intercalation of PVA between layers of \rm\lbrack Ca\sb2Al(OH)\sb6\rbrack\sp+\lbrack(OH){\cdot} 3H\sb2O\rbrack\sp- occurred during crystal growth, resulting in an organoceramic containing up to 40% polymer by weight. Polymer intercalation resulted in an expression of the interlayer by approximately 10 A, consistent with the formation of a double layer of PVA chains across each interlayer. Thermal degradation of the inorganic and polymeric components of the organoceramic occurred at higher temperatures than the individual materials. Compressive strength of PVA organoceramic powder compacts was significantly higher than that of \rm\lbrack Ca\sb2Al(OH)\sb6\rbrack\sp+\lbrack(OH){\cdot} 3H\sb2O\rbrack\sp- compacts, possibly reflecting substantial differences in particle morphologies.Made available in DSpace on 2011-05-07T13:14:39Z (GMT). No. of bitstreams: 2
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Previous issue date: 1993Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding ([email protected]) on 2011-05-07T14:52:12Z
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Organic materials for second-order nonlinear optics: Approaches to optimizing and stabilizing nonlinear optical effects
No full textThe main objective of this research has been to establish the potential of nonlinear optics (NLO) to study relationships between chemical structure and properties of organic materials. Using properly constructed molecules or photoactive dopants, phenomena such as molecular relaxation, dipolar ordering, poling dynamics, and intermolecular forces in organic materials were investigated. A second objective has been to identify mechanisms to optimize and stabilize second harmonic generation (SHG) signals through materials processing techniques. This investigation includes studies in three main topics: nonlinear optical properties of magnetically aligned alloys of nematic polymers and organic dyes, two-dimensional polymers, and novel single crystal films that exhibit zero-field SHG."The second order nonlinear optical response of a solidified nematic polymer containing a photoactive organic dye as a dissolved solute or as phase separated crystals was investigated upon exposure to a magnetic field. The magnetically aligned nematic alloy can be regarded as an ""Ising-like"" medium in which the nematic and the magnetic fields confine the dipolar dye molecules along directions parallel or anti-parallel to the external DC field. An increase of the second order susceptibility by a factor of five in an idealized system has been predicted by theory. Relative to theoretical predictions, magnetically induced order in the nematic solvent was found to result in second harmonic signals which are 6-9 times more intense and the second order susceptibility of the system triples."Due to the randomization of polar ordering after poling, the stability of SHG activity in the guest-host system was difficult to maintain. Thus, a special molecular architecture, i.e. a two-dimensional (2D) polymer, was investigated to address the stability problem. This investigation revealed that a chiral oligomer can be transformed into a two-dimensional structure through a dual chemical reaction. Homochiral recognition among strongly dipolar cyano groups was found to play an important role in the transformation of the oligomer to a 2D polymer. In contrast to its analogous comb polymer synthesized by free radical polymerization, this 2D polymer shows remarkable stability in SHG activity. Thermally stimulated discharge (TSD) results suggest that higher discharge currents correlate with higher values of \chi\sp{(2)}. Some derivative compounds of the 2D precursor exhibited enormous and stable SHG activity without poling, suggesting that the molecules crystallize into highly polar noncentrosymmetric structures. Through a series of analyses for the relationship between the chemical structure and SHG activity, a novel way to prepare promising SHG films was developed in one of the derivative compounds. The origin of this extraordinary NLO property was due to the formation of an active phase possibly consisting of aligned single crystals. This study shows the importance of materials processing and molecular tailoring in the development of NLO-active materials.Made available in DSpace on 2011-05-07T13:26:50Z (GMT). No. of bitstreams: 2
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Previous issue date: 1992Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding ([email protected]) on 2011-05-07T14:54:52Z
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Chiral macromolecules bearing configurationally ordered dipolar functional groups: Molecular design, synthesis and phases
No full textThe molecular attributes which govern the formation and structure of ordered phases in polymeric materials are poorly understood. This work studies the relationship between configurational order among dipolar functional groups bound to a semirigid polymer backbone and the nature of the condensed phases of these materials. The investigation first involved the synthesis of a family of macromolecules designed to address this relationship. The parent structures were polyesters possessing a periodic sequence and polar translational symmetry. Formal substitution of hydrogen by the nitrile functional group on the repeating unit of the parent backbone generates the chemical structure of the other members of this family. The extent of configurational order at the nitrile-bearing stereocenter was an important variable addressed in this work.The synthesis of the polyesters was achieved by direct, self-condensation of their corresponding hydroxyacid monomers. A carbodiimide-based esterification reaction was developed involving mild conditions for bringing about this polymerization. It was found that high molecular weight polymers could be prepared at room temperature and near neutral pH by employing the catalysts synthesized from 4-dimethylaminopyridine and p-toluenesulfonic acid. These conditions were established by studies with small molecule model reactions. Nitrile containing monomers were synthesized with absolute stereocontrol by using Enders asymmetric alkylation chemistry and a method was developed for conversion of the chiral hydrazone to the corresponding nitrile functional group with minimal loss of stereochemical purity.Physical characterization of phases formed by these new polymers involved thermal analysis, polarized light microscopy, as well as the synthesis and study of small-molecule model compounds. The model compounds had a structure which corresponded essentially to the dimer of the polymer repeat unit. The non-racemic model compound formed only a monotropic liquid crystal (LC) phase, while the racemate produced an enantiotropic LC phase. On cooling through the LC phase, the racemic model compound displayed hindered crystallization behavior relative to its non-racemic analogue.The configurationally disordered polymer gave a single transition on heating and on cooling as measured by differential scanning calorimetry. The configurationally ordered polymer, on the other hand, showed a double endotherm on heating but only a single transition on cooling. Using evidence obtained from polarized light microscopy on these two polymers and evidence obtained from a molecular weight series of the configurationally disordered polymers, it is suggested that a liquid crystalline phase formed in the case of the disordered polymer while a crystalline phase formed in the case of the configurationally ordered polymer. These findings are consistent with the behavior of the small molecule model compounds and were confirmed by independently conducted electron diffraction studies. Thus, the ordered phases formed by these polymers are dictated by the chemical order and symmetry of their respective backbones.Made available in DSpace on 2011-05-07T13:16:49Z (GMT). No. of bitstreams: 2
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Previous issue date: 1989Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding ([email protected]) on 2011-05-07T14:52:40Z
Item is restricted indefinitely.Restriction data tranferred 2014-07-01T11:24:17-05:00
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