Browsing by Author "Gormaz, Juan"

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    Plasma versus Erythrocyte Vitamin E in Renal Transplant Recipients, and Duality of Tocopherol Species
    (2019) Sotomayor, Camilo; Rodrigo, Ramón; Gomes, António; Gormaz, Juan; Pol, Robert; Minovi´c, Isidor; Eggersdorfer, Manfred; Vos, Michel; Riphagen, Ineke; H. de Borst, Martin; Nolte, Ilja; Berger, Stefan; Navis, Gerjan; Bakker, Stephan
    Redox imbalance is an adverse on-going phenomenon in renal transplant recipients (RTR). Vitamin E has important antioxidant properties that counterbalance its deleterious effects. However, plasma vitamin E affinity with lipids challenges interpretation of its levels. To test the hypothesis that erythrocyte membranes represent a lipids-independent specimen to estimate vitamin E status, we performed a cross-sectional study in a cohort of adult RTR (n = 113) recruited in a university setting (2015-2018). We compared crude and total lipids-standardized linear regression-derived coefficients of plasma and erythrocyte tocopherol species in relation to clinical and laboratory parameters. Strongly positive associations of fasting lipids with plasma tocopherol became inverse, rather than absent, in total lipids-standardized analyses, indicating potential overadjustment. Whilst, no variables from the lipids domain were associated with the tocopherol species measured from erythrocyte specimens. In relation to inflammatory status and clinical parameters with antioxidant activity, we found associations in directions that are consistent with either beneficial or adverse effects concerning α- or γ-tocopherol, respectively. In conclusion, erythrocytes offer a lipids-independent alternative to estimate vitamin E status and investigate its relationship with parameters over other biological domains. In RTR, α- and γ-tocopherol may serve as biomarkers of relatively lower or higher vulnerability to oxidative stress and inflammation, noticeably in opposite directions.
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    Platinum Analogs from a Chemical and Biological Point of View
    (2022) Retamal, Mauricio; Gormaz, Juan; Cortés, Ignacio; Campodónico, Paola
    Platinum (Pt) analogues are the most widely used chemotherapeutic agents in oncology, used alone or co-administered with other antineoplastic therapy and/or radiation. Pt-based chemotherapies are prescribed to treat a wide spectrum of specific malignancies, including digestive, lung, head and neck, prostate, testicular, ovarian, bladder, cervical, breast, sarcomas and melanomas, as well as several hematological cancers. Patients treated with Pt-based chemotherapies suffer significant adverse effects, limiting their use. Management of these toxic effects is a key factor for successful therapy. Considering that relatively few Pt drugs are clinically and broadly used worldwide, understanding the biochemical and biological basis for resistance to Pt drugs is crucial. Thus, our aim is to summarize current knowledge of the chemical and biological features of Pt-based molecules used in chemotherapy, primarily focusing on its effects on cell function and how some of these changes drive cell resistance to Pt-based molecules.

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