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Abstract: Background. Rituximab has been applied successfully in the treatment of indolent and aggressive CD20 positive B cell lymphomas, yet the exact in vivo mechanisms of its action have not been unambiguously explained. This study wastherefore aimed to confirm the presumed major mechanisms of action of rituximab and concomitantly to assess the effectiveness of first-line chemoimmunotherapy in high-risk patients with aggressive CD20 lymphomas. Patients, materials and methods. The activity of rituximab was tested in vitroon Raji and SU-DHL-4 cells using the cell proliferation assay and flow cytometry. In the clinical part of the study, 20 high-risk patients with aggressive CD 20 lymphomas were treated with R-CHOP. Results. Only complement-mediated cytotoxicity was observed under the in vitro applied experimental conditions. Neither the direct apoptotic effect nor the antibody-dependent cell-mediated cytotoxicity was detected probably due to a too low concentration of rituximab and a too low ratio of cytotoxic lymphocytes to tumor cells. The treatment outcome in patients was excellent since complete remissions were achieved in 90% of poor-risk patients at the end of primary treatment and 80% of patients were disease free at 18.5 months median observation period. Conclusions. According to our results, the complement-dependent cytotoxicity is an important mechanism of rituximab action in vitro. To achieve direct apoptosis, higher concentrations than 20 micro g/ml of rituximab should be used, while for an effective antibody-dependent cell-mediated cytotoxicity, the ratio of cytotoxic lymphocytes to tumor cells should be higher than 1:1. In the high- risk patients with aggressive CD20 lymphomas, the addition of rituximab to CHOP substantially improves the therapeutic results.
Published in DiRROS: 22.02.2024; Views: 150; Downloads: 38
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Abstract: Backround. Rituximab - the most widely used monoclonal antibody in the B cell lymphoid malignancies has been applied successfully in the treatment of relapsed and refractory indolent CD20 positive B cell lymphomas and more recently, also in the treatment of aggressive lymphomas in combination with standard chemotherapy. Albeit the chemo-immunotherapy has a wide range of potential applications, there are still several issues that have to be resolved: (1) the optimal scheduling of antibody-chemotherapy combinations, (2) the most active of these combinations, as well as (3) the predictors of response to rituximab. Patients and methods. To facilitate addressing the first two questions, we performed an analysis in 25 patients with different histological types of CD20 positive nonHodgkin's lymphomas (10 aggressive and 15 indolent). Seventeen patients were treated with chemo-immunotherapy for a relapse, and just in 8 patients rituximab was added to first line chemotherapy. Most of the responders received the CHOP regimen, but also otherregimens (FC, BVCPP) were effective in combination with rituximab. Results. The overall response rate was 76%, with 68% complete remissions. The median response duration has not been reached yet. The response was markedly better in the group of previously untreated patients, where the overall response rate reached 100%, with 7 patients in complete and 1 patient in partial remission. Most of the treatment failures occurred in heavily pretreated patients with aggressive lymphomas. No serious adverse effects wereobserved. Conclusion The chemo-immunotherapy improves the treatment outcomes in patients with untreated and relapsed CD20 positive nonHodgkin's lymphomas in comparison to chemotherapy alone. The combined treatment is the most effective when used as soon as possible (preferably as the first line treatment). (Abstract truncated at 2000 characters).
Published in DiRROS: 07.02.2024; Views: 180; Downloads: 39
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Abstract: Verticillium dahliae Kleb., the causal agent of Verticillium wilts, is a devastating plant disease affecting many plant species. Fungus V. dahliae was detected in a partially artificially established Acer pseudoplatanus L. forest stand in central Slovenia. This finding incited further study about the risk of different sources of V. dahliae isolates for maples in forests and the pathogenicity of three V. dahliae isolates of different origins was tested on saplings of A. pseudoplatanus, A. platanoides L., and A. campestre L. The inoculated saplings exhibited disease symptoms, i.e., leaf necrosis and wilting. At the end of the pathogenicity test, typical xylem browning was visible on the cross-sections, and the pathogen was successfully re-isolated. The isolates showed significant differences in their pathogenicity to specific maple hosts, with the agricultural isolate (originated from bell pepper) being the most aggressive on all three maple species. The disease severity index (DSI) and relative area under the disease progress curve (rAUDPC), as well as the success of re-isolation, indicate that A. platanoides is the most susceptible to inoculation with V. dahliae. In addition, significant differences in sapling biomass were observed between treated and control plants. These results suggest that maples in forest stands are threatened by V. dahliae, and biosecurity measures should be considered and implemented in forest management to reduce the transmission and potential spread of the pathogen.
Keywords: Verticillium wilt, Acer spp., pathogenicity test, Disease severity index, DSI, Area under the disease progress curve, AUDPC, biosecurity
Published in DiRROS: 07.02.2024; Views: 180; Downloads: 82
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Abstract: One of the key steps of the molecular identification of bark beetles is obtaining a sufficient quantity of high-quality DNA extract. In this study, we investigated the influence of different storage procedures for Ips typographus (L.) specimens and various DNA extraction protocols on the quantity and quality of DNA intended for use in molecular diagnostics. Adult beetles were frozen at -20 °C, either dry or in ethanol. We tested four different protocols for DNA extraction. We compared the quantity of extracted DNA and assessed its quality with PCR and Sanger sequencing. Different storage protocols had no significant effect on the quantity of DNA extracted. However, freezing specimens in ethanol provided higher-quality DNA for molecular applications. Only two of the extraction protocols produced sequenceable amplicons, and the difference in the amount of extracted DNA between them was not significant. We propose the optimal combination of storing specimens in ethanol at -20°C and using the Nucleospin Insect DNA extraction kit from Macherey Nagel, enabling a timeefficient identification process.
Keywords: early detection, specimen storage, total DNA extraction, PCR, polymerase chain reaction, Sanger sequencing, molecular diagnostics
Published in DiRROS: 02.02.2024; Views: 424; Downloads: 129
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Keywords: Co-Cr alloys, microstructure analysis, hardness, wear resistance
Published in DiRROS: 01.02.2024; Views: 189; Downloads: 118
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