771. Optimization of electrode position and electric pulse amplitude in electrochemotherapyAnže Županič, Selma Čorović, Damijan Miklavčič, 2008, original scientific article Abstract: Background. In addition to the chemotherapeutic drug being present within the tumor during electric pulse delivery, successful electrochemotherapy requires the entire tumor volume to be subjected to a sufficiently high electric field,while the electric field in the surrounding healthy tissue is as low as possible to prevent damage. Both can be achieved with appropriate positioning of the electrodes and appropriate amplitude of electric pulses. Methods. We used 3D finite element numerical models and a genetic optimization algorithm to determine the optimum electrode configuration and optimum amplitude of electric pulses for treatment of three subcutaneous tumor models of different shapes and sizes and a realistic brain tumor model acquired from medical images. Results. In all four tumor cases, parallel needle electrode arrays were a better choice than hexagonal needle electrode arrays, since their utilization required less electric current and caused less healthy tissue damage. In addition, regardless of tumor geometry or needle electrode configuration, the optimum depth of electrode insertion was in all cases deeper than the deepest part of the tumor. Conclusions. Our optimization algorithm was able to determine the best electrode configuration in all four presented models and with further improvement it could be a useful tool in clinical electrochemotherapy treatment planning.
Published in DiRROS: 08.03.2024; Views: 184; Downloads: 53
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772. Evolution of microstructure and embrittlement during the tempering process in SiCrCu medium-carbon steelsPavel Salvetr, Aleksandr Gokhman, Črtomir Donik, Zbyšek Nový, Jakub Kotous, Matjaž Godec, 2023, original scientific article Keywords: medium-carbon steel, tempering martensite embrittlement, microstructure, mechanical properties
Published in DiRROS: 08.03.2024; Views: 191; Downloads: 104
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773. Evaluation of shRNA-mediated gene silencing by electroporation in LPB fibrosarcoma cellsSuzana Vidic, Urška Kamenšek, Maja Čemažar, 2008, original scientific article Abstract: Background. Silencing oncogenes or other genes that contribute to tumor malignancy and progression offers a promising approach to treating cancer. Specific and efficient silencing of gene expression can be achieved by RNA interference (RNAi) technology using small interfering RNA (siRNA) or short hairpin RNA (shRNA). However, a major challenge in RNAi technology is effective delivery of interfering molecules into target cells. The aim of our study was to evaluate electroporation as a perspective method for efficient invitro transfection of LPB fibrosarcoma cells with plasmid DNA expressing shRNA. Methods. Induction of shRNA-mediated gene silencing by electroporation was determined by fluorescence microscopy, flow cytometry and western blot analysis. The effect of electroporation conditions on cell survival and proliferation was determined by clonogenic assay. Results and conclusions. Ourresults demonstrated that electroporation is a feasible and effective method for delivery of plasmid DNA expressing shRNA into cancer cells in vitro. Electrotransfection of murine LPB fibrosarcoma cells, continuously expressing green fluorescence protein - GFP (LPBGFP), with plasmid DNA encoding shRNA-GFP, reduced GFP expression, which was determined on the protein level, as well as by measurement of GFP fluorescence intensity. A pronounced reduction in GFP expression level was detected from the second to the fifth day after treatment. Moreover, the method is easy to perform and showed low cell damaging effects, which are the most important and preferential factors for further in vivo studies.
Published in DiRROS: 08.03.2024; Views: 201; Downloads: 53
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774. Cysteine cathepsins and stefins in head and neck cancer : an update of clinical studiesPrimož Strojan, 2008, review article Abstract: Background. Cancer of the head and neck represents a diverse group of malignant diseases; so far, no factor in a wide spectrum of biochemical and histological candidate-markers has yet been identified to predict reliably thenatural course of the disease or its response to the therapy to be used in routine clinical practice. Among the factors that promote tumor growth and invasion, several protease systems, implemented in proteolytic degradation of extracellular matrix components, were studied, including papain-like lysosomalcysteine proteases (e.g. cathepsins B and L) and their physiological inhibitors cystatins (e.g. stefins A and B, cystatin C). The aim of the present report is to review the published studies on clinical applicability ofcysteine cathepsins and their endogenous inhibitors stefins in squamous cellcarcinoma of the head and neck and to present recent research results fromthis area conducted jointly by the Institute of Oncology Ljubljana and ENTDepartment of the University Medical Center Ljubljana, Slovenia. Conclusions. According to our experience, immunohistochemical staining of cysteine cathepsins and stefins seems to be of limited value for predicting either treatment response or patientsć survival. However, the results of studies on stefin A in tumor tissue cytosols should be considered hypothesis-generating and deserves further evaluation in the frame of prospective controlled multicentric clinical study.
Published in DiRROS: 08.03.2024; Views: 149; Downloads: 54
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776. Characterisation of the microstructure and defects during the direct energy deposition of hybrid Ti6Al4V in a low-quality atmosphereSimon Malej, Črtomir Donik, Matej Balažic, Matija Bizjak, Marko Kač, Matjaž Godec, 2023, original scientific article Keywords: direct energy deposition, Ti6Al4V, protective atmosphere
Published in DiRROS: 08.03.2024; Views: 201; Downloads: 96
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