11. Chloroplast redox state changes mark cell-to-cell signaling in the hypersensitive responseTjaša Lukan, Anže Županič, Tjaša Mahkovec Povalej, Jacob O. Brunkard, Mirjam Kmetič, Mojca Juteršek, Špela Baebler, Kristina Gruden, 2023, original scientific article Abstract: Bisphenol A (BPA) is one of the most commonly used substances in the manufacture ofvarious everyday products. Growing concerns about its hazardous properties, including endocrinedisruption and genotoxicity, have led to its gradual replacement by presumably safer analogues inmanufacturing plastics. The widespread use of BPA and, more recently, its analogues has increasedtheir residues in the environment. However, our knowledge of their toxicological profiles is limitedand their combined effects are unknown. In the present study, we investigated the toxic effectscaused by single bisphenols and by the combined exposure of BPA and its two analogues, BPAP andBPC, after short (24-h) and prolonged (96-h) exposure in HepG2 spheroids. The results showed thatBPA did not reduce cell viability in HepG2 spheroids after 24-h exposure. In contrast, BPAP andBPC affected cell viability in HepG2 spheroids. Both binary mixtures (BPA/BPAP and BPA/BPC)decreased cell viability in a dose-dependent manner, but the significant difference was only observedfor the combination of BPA/BPC (both at 40μM). After 96-h exposure, none of the BPs studiedaffected cell viability in HepG2 spheroids. Only the combination of BPA/BPAP decreased cellviability in a dose-dependent manner that was significant for the combination of 4μM BPA and 4μMBPAP. None of the BPs and their binary mixtures studied affected the surface area and growth ofspheroids as measured by planimetry. In addition, all BPs and their binary mixtures studied triggeredoxidative stress, as measured by the production of reactive oxygen species and malondialdehyde,at both exposure times. Overall, the results suggest that it is important to study the effects of BPsas single compounds. It is even more important to study the effects of combined exposures, as thecombined effects may differ from those induced by single compounds.
Keywords: chloroplast redox state, hypersensitive response (HR)-conferred resistance, immune signaling, live cell imaging, Solanum tuberosum (potato), spatiotemporal analysis, stromules, virus resistance
Published in DiRROS: 13.04.2023; Views: 410; Downloads: 135
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12. Stroop in motion : neurodynamic modulation underlying interference control while sitting, standing, and walkingManca Peskar, Nina Omejc, Maja Maša Šömen, Aleksandar Miladinović, Klaus Gramann, Uroš Marušič, 2023, original scientific article Abstract: There is conflicting evidence about how interference control in healthy adults is affected by walking as compared to standing or sitting. Although the Stroop paradigm is one of the best-studied paradigms to investigate interference control, the neurodynamics associated with the Stroop task during walking have never been studied. We investigated three Stroop tasks using variants with increasing interference levels – word-reading, ink-naming, and the switching of the two tasks, combined in a systematic dual-tasking fashion with three motor conditions – sitting, standing, and treadmill walking. Neurodynamics underlying interference control were recorded using the electroencephalogram. Worsened performance was observed for the incongruent compared to congruent trials and for the switching Stroop compared to the other two variants. The early frontocentral event-related potentials (ERPs) associated with executive functions (P2, N2) differentially signaled posture-related workloads, while the later stages of information processing indexed faster interference suppression and response selection in walking compared to static conditions. The early P2 and N2 components as well as frontocentral Theta and parietal Alpha power were sensitive to increasing workloads on the motor and cognitive systems. The distinction between the type of load (motor and cognitive) became evident only in the later posterior ERP components in which the amplitude non-uniformly reflected the relative attentional demand of a task. Our data suggest that walking might facilitate selective attention and interference control in healthy adults. Existing interpretations of ERP components recorded in stationary settings should be considered with care as they might not be directly transferable to mobile settings.
Keywords: Stroop task, mobile brain imaging, mobile body imaging, event-related potential, dual tasking
Published in DiRROS: 29.03.2023; Views: 428; Downloads: 271
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13. Estimating quantitative physiological and morphological tissue parameters of murine tumor models using hyperspectral imaging and optical profilometryTadej Tomanič, Luka Rogelj, Jošt Stergar, Boštjan Markelc, Tim Božič, Simona Kranjc Brezar, Gregor Serša, Matija Milanič, 2022, original scientific article Abstract: Understanding tumors and their micro-environment are essential for successfuland accurate disease diagnosis. Tissuephysiology and morphology are altered intumors compared to healthy tissues, andthere is a need to monitor tumors and their surrounding tissues, includingblood vessels, non-invasively. This preliminary study utilizes a multimodaloptical imaging system combining hyperspectral imaging (HSI) and three-dimensional (3D) optical profilometry (OP) to capture hyperspectral imagesand surface shapes of subcutaneously grown murine tumor models. Hyper-spectral images are corrected with 3D OP data and analyzed using the inverse-adding doubling (IAD) method to extract tissue properties such as melaninvolume fraction and oxygenation. Blood vessels are segmented using theB-COSFIRE algorithm from oxygenation maps. From 3D OP data, tumor vol-umes are calculated and compared to manual measurements using a verniercaliper. Results show that tumors can be distinguished from healthy tissuebased on most extracted tissue parameters (p<0:05). Furthermore, blood oxy-genation is 50% higher within the blood vessels than in the surrounding tissue,and tumor volumes calculated using 3D OP agree within 26% with manualmeasurements using a vernier caliper. Results suggest that combining HSI andOP could provide relevant quantitative information about tumors and improvethe disease diagnosis.
Keywords: medical physics, hyperspectral imaging, diffuse reflectance spectroscopy, blood vessels, tumors
Published in DiRROS: 08.09.2022; Views: 578; Downloads: 196
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14. Quantitative imaging biomarkers of immune-related adverse events in immune-checkpoint blockade-treated metastatic melanoma patients : a pilot studyNežka Hribernik, Daniel T. Huff, Andrej Studen, Katarina Zevnik, Žan Klaneček, Hamid Emamekhoo, Katja Škalič, Robert Jeraj, Martina Reberšek, 2022, original scientific article Abstract: Purpose: To develop quantitative molecular imaging biomarkers of immune-related adverse event (irAE) development in malignant melanoma (MM) patients receiving immune-checkpoint inhibitors (ICI) imaged with 18F-FDG PET/CT. Methods: 18F-FDG PET/CT images of 58 MM patients treated with anti-PD-1 or anti-CTLA-4 ICI were retrospectively analyzed for indication of irAE. Three target organs, most commonly affected by irAE, were considered: bowel, lung, and thyroid. Patient charts were reviewed to identify which patients experienced irAE, irAE grade, and time to irAE diagnosis. Target organs were segmented using a convolutional neural network (CNN), and novel quantitative imaging biomarkers - SUV percentiles (SUVX%) of 18F-FDG uptake within the target organs - were correlated with the clinical irAE status. Area under the receiver-operating characteristic curve (AUROC) was used to quantify irAE detection performance. Patients who did not experience irAE were used to establish normal ranges for target organ 18F-FDG uptake. Results: A total of 31% (18/58) patients experienced irAE in the three target organs: bowel (n=6), lung (n=5), and thyroid (n=9). Optimal percentiles for identifying irAE were bowel (SUV95%, AUROC=0.79), lung (SUV95%, AUROC=0.98), and thyroid (SUV75%, AUROC=0.88). Optimal cut-offs for irAE detection were bowel (SUV95%>2.7 g/mL), lung (SUV95%>1.7 g/mL), and thyroid (SUV75%>2.1 g/mL). Normal ranges (95% confidence interval) for the SUV percentiles in patients without irAE were bowel [1.74, 2.86 g/mL], lung [0.73, 1.46 g/mL], and thyroid [0.86, 1.99 g/mL]. Conclusions: Increased 18F-FDG uptake within irAE-affected organs provides predictive information about the development of irAE in MM patients receiving ICI and represents a potential quantitative imaging biomarker for irAE. Some irAE can be detected on 18F-FDG PET/CT well before clinical symptoms appear.
Keywords: melanoma, malignant melanoma, immune-checkpoint inhibitors, molecular imaging biomarkers
Published in DiRROS: 07.09.2022; Views: 549; Downloads: 154
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15. Comparison of selected dimensionality reduction methods for detection of root-knot nematode infestations in potato tubers using hyperspectral imagingJanez Lapajne, Matej Knapič, Uroš Žibrat, original scientific article Keywords: hyperspectral imaging, dimensionality reduction, LDA, PLS, PCA, RandomForest, ReliefF, XGB, Meloidogyne, Solanum tuberosum
Published in DiRROS: 06.09.2022; Views: 517; Downloads: 189
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16. Dynamic contrast-enhanced MRI in malignant pleural mesothelioma : prediction of outcome based on DCE-MRI measurements in patients undergoing cytotoxic chemotherapyMartina Vivoda Tomšič, Peter Korošec, Viljem Kovač, Sotirios Bisdas, Katarina Šurlan Popović, 2022, original scientific article Abstract: The malignant pleural mesothelioma (MPM) response rate to chemotherapy is low. The identification of imaging biomarkers that could help guide the most effective therapy approach for individual patients is highly desirable. Our aim was to investigate the dynamic contrast-enhanced (DCE) MR parameters as predictors for progression-free (PFS) and overall survival (OS) in patients with MPM treated with cisplatin-based chemotherapy. Methods: Thirty-two consecutive patients with MPM were enrolled in this prospective study. Pretreatment and intratreatment DCE-MRI were scheduled in each patient. The DCE parameters were analyzed using the extended Tofts (ET) and the adiabatic approximation tissue homogeneity (AATH) model. Comparison analysis, logistic regression and ROC analysis were used to identify the predictors for the patient's outcome. Results: Patients with higher pretreatment ET and AATH-calculated Ktrans and ve values had longer OS (P≤.006). Patients with a more prominent reduction in ET-calculated Ktrans and kep values during the early phase of chemotherapy had longer PFS (P =.008). No parameter was identified to predict PFS. Pre-treatment ET-calculated Ktrans was found to be an independent predictive marker for longer OS (P=.02) demonstrating the most favourable discrimination performance compared to other DCE parameters with an estimated sensitivity of 89% and specificity of 78% (AUC 0.9, 95% CI 0.74-0.98, cut off > 0.08 min-1). Conclusions: In the present study, higher pre-treatment ET-calculated Ktrans values were associated with longer OS. The results suggest that DCE-MRI might provide additional information for identifying MPM patients that may respond to chemotherapy.
Keywords: cisplatin, magnetic resonance imaging, mesothelioma
Published in DiRROS: 06.04.2022; Views: 1193; Downloads: 509
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17. Inter-observer reliability for different point-of-care lung ultrasound findings in mechanically ventilated critically ill COVID-19 patientsAlan Šustić, Marko Mirošević, Konstanty Szuldrzynski, Robert Marčun, Mehmed Haznadar, Matej Podbregar, Alen Protić, 2021, other scientific articles Keywords: COVID-19 -- diagnosis -- diagnostic imaging, ultrasonography, artificial respiration, critical care, critical illness, lung ultrasound, mechanical ventilation
Published in DiRROS: 16.06.2021; Views: 984; Downloads: 289
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18. Dynamic contrast-enhanced MRI of malignant pleural mesothelioma : a comparative study of pharmacokinetic models and correlation with mRECIST criteriaMartina Vivoda Tomšič, Sotirios Bisdas, Viljem Kovač, Igor Serša, Katarina Šurlan Popović, 2019, original scientific article Abstract: BACKGROUND: Malignant pleural mesothelioma (MPM) is a rare and aggressive thoracic malignancy that is difficult to cure. Dynamic contrast-enhanced (DCE) MRI is a functional imaging technique used to analyze tumor microvascular properties and to monitor therapy response. Purpose of this study was to compare two tracer kinetic models, the extended Tofts (ET) and the adiabatic approximation tissue homogeneity model (AATH) for analysis of DCE-MRI and examine the value of the DCE parameters to predict response to chemotherapy in patients with MPM. METHOD: This prospective, longitudinal, single tertiary radiology center study was conducted between October 2013 and July 2015. Patient underwent DCE-MRI studies at three time points: prior to therapy, during and after cisplatin-based chemotherapy. The images were analyzed using ET and AATH models. In short-term follow-up, the patients were classified as having disease control or progressive disease according to modified response evaluation criteria in solid tumors (mRECIST) criteria. Receiver operating characteristic curve analysis was used to examine specificity and sensitivity of DCE parameters for predicting response to therapy. Comparison tests were used to analyze whether derived parameters are interchangeable between the two models. RESULTS: Nineteen patients form the study population. The results indicate that the derived parameters are not interchangeable between the models. Significant correlation with response to therapy was found for AATH-calculated median pre-treatment efflux rate (kep) showing sensitivity of 83% and specificity of 100% (AUC 0.9). ET-calculated maximal pre-treatment kep showed 100% sensitivity and specificity for predicting treatment response during the early phase of the therapy and reached a favorable trend to significant prognostic value post-therapy. CONCLUSION: Both models show potential in predicting response to therapy in MPM. High pre-treatment kep values suggest MPM disease control post-chemotherapy.
Keywords: biomarker, magnetic resonance imaging, mesothelioma, perfusion, response evaluation criteria in solid
tumors, prognosis
Published in DiRROS: 23.09.2020; Views: 1330; Downloads: 966
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19. Discrimination between abiotic and biotic drought stress in tomatoes using hyperspectral imagingNik Susič, Uroš Žibrat, Saša Širca, Polona Strajnar, Jaka Razinger, Matej Knapič, Andrej Vončina, Gregor Urek, Barbara Gerič Stare, original scientific article Abstract: Crop plants are subjected to various biotic and abiotic stresses. Both root-knot nematodes (biotic stress) and water deficiency (abiotic stress) lead to similar drought symptoms in the plant canopy. In this work, hyperspectral imaging was used for early detection of nematode infestation and water deficiency (drought) stress in tomato plants. Hyperspectral data in the range from 400 to 2500 nm of plants subjected to different watering regimes and nematode infestation levels were analysed by partial least squares – discriminant analysis (PLS-DA) and partial least squares – support vector machine (PLS-SVM) classification. PLS-SVM classification achieved up to 100% accuracy differentiating between well-watered and water-deficient plants, and between 90 and 100% when identifying nematode-infested plants. Grouping the data according to the time of imaging increased the accuracy of classification. Shortwave infrared spectral regions associated with the OH and CH stretches were most relevant for the identification of nematode infested plants and severity of infestation. This study demonstrates the capability of hyperspectral imaging to identify and discriminate between biotic and abiotic plant stresses.
Keywords: nematode, Hyperspectral imaging, Drought stress, Root-knot nematode, Tomato
Published in DiRROS: 20.07.2018; Views: 3897; Downloads: 2404
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