1. Effects of 30-day high-dose omega-3 fatty acid supplementation on plasma oxidative stress enzyme activities in recreational and trained runners : a pilot studyBojan Martinšek, Milan Skitek, Tina Kosjek, Leon Bedrač, Evgen Benedik, 2025, original scientific article Abstract: Background: Physical activity induces the production of reactive oxygen species (ROS), which, at moderate levels mediate beneficial physiological adaptations, including insulin sensitivity and enhanced antioxidant defense. However, excessive ROS production during intense exercise may exceed endogenous antioxidant capacity, leading to oxidative stress and muscle damage. Objective: This study examined the effects of 30-day high-dose omega-3 fatty acid supplementation (9 g/day) on plasma fatty acid composition and the activity of antioxidant enzymes in recreational (n = 11) and trained (n = 10) runners, with emphasis on group- and time-specific responses. Methods: Plasma levels of arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) were assessed at three time points: pre-, during, and post-supplementation period. Enzymatic activities of glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) were measured at six time points, including before and after exercise sessions involving a 2800 m run followed by a 400 m sprint. Results: Omega-3 supplementation increased plasma EPA and DHA. In trained runners, it was associated with a transient reduction in GPx and a pronounced mid-phase decline in SOD, whereas enzyme activities remained stable in recreational runners. CAT activity did not change significantly in either group. Conclusions: Short-term high-dose omega-3 supplementation modulates antioxidant enzyme activity in a group- and time-dependent manner. The observed downregulation of GPx and SOD in trained runners may reflect altered redox signaling; however, its relevance for exercise performance remains uncertain. Further studies are warranted to elucidate the physiological and functional consequences of these findings.
Keywords: physical activity, running, reactive oxygen species, omega-3 fatty acids, polyunsaturated fatty acids, catalase, glutathione peroxidase, superoxide dismutase
Published in DiRROS: 23.12.2025; Views: 333; Downloads: 224
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2. The role of polymorpisms in glutathione-related genes in asbestos-related diseasesAlenka Franko, Katja Goričar, Metoda Dodič-Fikfak, Viljem Kovač, Vita Dolžan, 2021, original scientific article Abstract: The study investigated the influence of GCLC, GCLM, GSTM1, GSTT1 and GSTP1 polymorphisms, as well as the influence of interactions between polymorphism and interactions between polymorphisms and asbestos exposure, on the risk of developing pleural plaques, asbestosis and malignant mesothelioma (MM). Subjects and methods. The cross sectional study included 940 asbestos-exposed subjects, among them 390 subjects with pleural plaques, 147 subjects with asbestosis, 225 subjects with MM and 178 subjects with no asbestos-related disease. GCLC rs17883901, GCLM rs41303970, GSTM1 null, GSTT1 null, GSTP1 rs1695 and GSTP1 rs1138272 genotypes were determined using PCR based methods. In statistical analysis, logistic regression was used. Results. GSTT1 null genotype was associated with the decreased risk for pleural plaques (OR = 0.63; 95% CI = 0.40% 0.98; p = 0.026) and asbestosis (OR = 0.51; 95% CI = 0.28%0.93; p = 0.028), but not for MM. A positive association was found between GSTP1 rs1695 AG + GG vs. AA genotypes for MM when compared to pleural plaques (OR = 1.39; 95% CI = 1.00%1.94; p = 0.049). The interactions between different polymorphisms showed no significant influence on the risk of investigated asbestos-related diseases. The interaction between GSTT1 null polymorphism and asbestos exposure decreased the MM risk (OR = 0.17; 95% CI = 0.03%0.85; p = 0.031). Conclusions. Our findings suggest that GSTT1 null genotype may be associated with a decreased risk for pleural plaques and asbestosis, may modify the association between asbestos exposure and MM and may consequently act protectively on MM risk. This study also revealed a protective effect of the interaction between GSTP1 rs1695 polymorphism and asbestos exposure on MM risk.
Keywords: polymorphisms, glutathione-related genes, asbestos, malignant mesothelioma
Published in DiRROS: 19.07.2024; Views: 1355; Downloads: 420
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3. Pharmacogenomic markers of glucorticoid responses in the initial phase of remission induction therapy in childhood acute lymphoblastic leukemiaVladimir Gasic, Branka Zukic, Biljana Stanković, Dragana Janić, Lidija Dokmanovic, Jelena Lazic, Nada Krstovski, Vita Dolžan, Janez Jazbec, Sonja Pavlovič, Nikola Kotur, 2018, original scientific article Keywords: pharmacogenomics, childhood ALL, glucocorticoids, glucocorticoid receptor gene, glutathione S-transferase genes, multidrug resistance 1 gene
Published in DiRROS: 11.06.2024; Views: 1270; Downloads: 423
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4. The role of oxygen in new vinification technologies of white and red winesKlemen Lisjak, 2007, doctoral dissertation Keywords: winemaking, wines, musts, chemical composition, white wines, red wines, oxygen, oxidation, pressing, hyperreduction, microoxygenation, glutathione, caftaric acid, coutaric acid, fertaric acid, hydroxycinnamates, anthocyanins, polyphenols
Published in DiRROS: 06.09.2022; Views: 2035; Downloads: 714
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