1. In vitro and in vivo evaluation of electrochemotherapy with trans-platinum analogue trans-[PtCl2(3-Hmpy)2]Simona Kranjc Brezar, Maja Čemažar, Gregor Serša, Janez Ščančar, Sabina Grabner, 2017, original scientific article Abstract: Background. Cisplatin is used in cancer therapy, but its side effects and acquired resistance to cisplatin have led to the synthesis and evaluation of new platinum compounds. Recently, the synthesized platinum compound trans- [PtCl2(3-Hmpy)2] (3-Hmpy = 3-hydroxymethylpyridine) (compound 2) showed a considerable cytotoxic and antitumour effectiveness. To improve compound 2 cytotoxicity in vitro and antitumour effectiveness in vivo, electroporation was used as drug delivery approach to increase membrane permeability (electrochemotherapy). Materials and methods. In vitro, survival of sarcoma cells with different intrinsic sensitivity to cisplatin (TBLCl2 sensitive, TBLCl2Pt resistant and SA-1 moderately sensitive) was determined using a clonogenic assay after treatment with compound 2 or cisplatin electrochemotherapy. In vivo, the antitumour effectiveness of electrochemotherapy with compound 2 or cisplatin was evaluated using a tumour growth delay assay. In addition, platinum in the serum, tumours and platinum bound to the DNA in the cells were performed using inductively coupled plasma mass spectrometry. Results. In vitro, cell survival after treatment with compound 2 electrochemotherapy was significantly decreased in all tested sarcoma cells with different intrinsic sensitivity to cisplatin (TBLCl2 sensitive, TBLCl2Pt resistant and SA-1 moderately sensitive). However, this effect was less pronounced compared to cisplatin. Interestingly, the enhancement factor (5-fold) of compound 2 cytotoxicity was equal in cisplatin-sensitive TBLCl2 and cisplatin-resistant TBLCl2Pt cells. In vivo, the growth delay of subcutaneous tumours after treatment with compound 2 electrochemotherapy was lower compared to cisplatin. The highest antitumour effectiveness after cisplatin or compound 2 electrochemotherapy was obtained in TBLCl2 tumours, resulting in 67% and 11% of tumour cures, respectively. Compound 2 induced significantly smaller loss of animal body weight compared to cisplatin. Furthermore, platinum amounts in tumours after compound 2 or cisplatin electrochemotherapy were approximately 2-fold higher compared to the drug treatment only, and the same increase of platinum bound to DNA was observed. Conclusions. The obtained results in vitro and in vivo suggest compound 2 as a potential antitumour agent in electrochemotherapy.
Keywords: platinum analogue, cisplatin, elektroporation, electrochemotherapy, 3-Hmpy
Published in DiRROS: 31.05.2024; Views: 29; Downloads: 5
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2. Febrile neutropenia in chemotherapy treated small-cell lung cancer patientsRenata Režonja, Iztok Grabnar, Tomaž Vovk, Aleš Mrhar, Viljem Kovač, Tanja Čufer, 2015, original scientific article Abstract: Chemotherapy with platinum agent and etoposide for small-cell lung cancer (SCLC) is supposed to be associated with intermediate risk (10-20%) of febrileneutropenia. Primary prophylaxis with granulocyte colonystimulating factors (G-CSFs) is not routinely recommended by the treatment guidelines. However, in clinical practice febrile neutropenia is often observed with standard etoposide/platinum regimen. The aim of this analysis was to evaluate the frequency of neutropenia and febrile neutropenia in advanced SCLC patients in the first cycle of standard chemotherapy. Furthermore, we explored the association between severe neutropenia and etoposide peak plasma levels inthe same patients. The case series based analysis of 17 patients with advanced SCLC treated with standard platinum/etoposide chemotherapy, already included in the pharmacokinetics study with etoposide, was performed. Grade 3/4 neutropenia and febrile neutropenia, observed after the first cycle are reported. The neutrophil counts were determined on day one of the second cycle unless symptoms potentially related to neutropenia occurred. Adverse events were classified according to Common Toxicity Criteria 4.0. Additionally, association between severe neutropenia and etoposide peak plasma concentrations, which were measured in the scope of pharmacokinetic study, was explored. Two out of 17 patients received primary GCS-F prophylaxis. In 15 patient who did not receive primary prophylaxis the rates of both grade 3/4 neutropenia and febrile neutropenia were high (8/15 (53.3%) and 2/15 (13.3%), respectively), already in the first cycle of chemotherapy. One patient died due to febrile neutropenia related pneumonia. Neutropenic events are assumed to be related to increased etoposide plasma concentrations after a standard etoposide and cisplatin dose. While the mean etoposide peak plasma concentration in the first cycle of chemotherapy was 17.6 mg/l, the highest levels of 27.07 and 27.49 mg/l were determined in two patients with febrile neutropenia. Our study indicates that there is a need to reduce the risk of neutropenic events in chemotherapy treated advanced SCLC, starting in the first cycle. Mandatory use of primary G-CSF prophylaxis might be considered. Alternatively, use of improved risk models for identification of patients with increased risk for neutropenia and individualization of primary prophylaxis based on not only clinical characteristics but also on etoposide plasma concentration measurement, could be a new, promising options that deserves further evaluation.
Keywords: small cell lung cancer, platinum-etoposide chemotherapy, etoposide, febrile neutropenia, plasma drug concentration
Published in DiRROS: 22.04.2024; Views: 127; Downloads: 60
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3. Mechanistic study of fast performance decay of PtCu alloy-based catalyst layers for polymer electrolyte fuel cells through electrochemical impedance spectroscopyMaximilian Grandi, Matija Gatalo, Ana Rebeka Kamšek, Gregor Kapun, Kurt Mayer, Francisco Ruiz-Zepeda, Martin Šala, Bernhard Marius, Marjan Bele, Nejc Hodnik, Merit Bodner, Miran Gaberšček, Viktor Hacker, 2023, original scientific article Keywords: PEFC, catalyst layer, platinum–copper, degradation, ionomer, electrochemical impedance spectroscopy, membrane electrode assembly
Published in DiRROS: 23.06.2023; Views: 402; Downloads: 202
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4. Photo, thermal and photothermal activity of ▫$TiO_2$▫ supported Pt catalysts for plasmon-driven environmental applicationsGregor Žerjav, Zafer Say, Janez Zavašnik, Matjaž Finšgar, Christoph Langhammer, Albin Pintar, 2023, original scientific article Abstract: TiO2+Pt plasmonic solids with 1 wt% Pt and different TiO2 supports (anatase nanoparticles (TNP), polycrystalline nanorods (a-TNR) and single-crystal anatase nanorods (TNR)) were synthesized using the wet impregnation technique and tested as photo, thermal and photothermal catalysts in gas-solid and gas-liquid-solid reactions. Due to the different charges of the TiO2 support surfaces, Pt particles with different sizes, crystallinities and degrees of interaction with the TiO2 supports were formed during the synthesis. The heights of the Schottky barrier (SBH) were 0.38 eV for the a-TNR+Pt, 0.41 eV for the TNP+Pt, and 0.50 eV for the TNR+Pt samples, respectively. The low visible-light-triggered photocatalytic activity of the TNR+Pt catalyst toward the oxidation of water-dissolved bisphenol A (BPA) is attributed to its high SBH and active site deactivation due to the adsorption of BPA and/or BPA oxidation products. The highest photothermal catalytic H2-assisted NO2 reduction rate was expressed by the TNR+Pt catalyst. This can be ascribed to the presence of a narrow particle size distribution of small Pt particles, the absence of the Pt catalysed reduction of the TNR support at higher temperatures, and the lower rate of re-injection of “hot electrons” from the TNR support to the Pt particles.
Keywords: heterogeneous photocatalysis, titanium dioxide, plasmonic noble metal, platinum particles, visible light illumination, Schottky barrier height, bisphenol A, wastewater treatment, NOx abatement, air cleaning, microreactor, thermal catalysis, photothermal catalysis
Published in DiRROS: 23.06.2023; Views: 413; Downloads: 207
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5. Assembly of Pt nanoparticles on graphitized carbon nanofibers as hierarchically-structured electrodesNejc Hodnik, Luigi Romano, Primož Jovanovič, Francisco Ruiz-Zepeda, Marjan Bele, Filippo Fabbri, Luana Persano, Andrea Camposeo, Dario Pisignano, 2020, original scientific article Keywords: electrocatalysis, in-situ annealing STEM, platinum nanoparticles, electrodes, electrospinning
Published in DiRROS: 26.11.2020; Views: 1882; Downloads: 1169
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6. Comparison of Pt-Cu/C with benchmark Pt-Co/C : metal dissolution and their surface interactionsMatija Gatalo, Primož Jovanovič, Urša Petek, Martin Šala, Vid Simon Šelih, Francisco Ruiz-Zepeda, Marjan Bele, Nejc Hodnik, Miran Gaberšček, 2019, original scientific article Keywords: oxygen reduction reaction, proton exchange membrane fuel cell, platinum alloy, metal dissolution, electrochemical flow cell coupled to inductively coupled plasma mass spectrometer
Published in DiRROS: 23.11.2020; Views: 1509; Downloads: 1100
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