Lipid peroxidation as a predictive biomarker of the early stage of cancer.

Prostate cancer continues to be a major cause of morbidity and mortality in men around the world. The data concerning the antioxidant status and the degree of lipid peroxidation at the moment of the initiation of cancer is limited. The aim of this research is to assess the effect of selected minerals (zinc, selenium, iron, copper and calcium) on the growth of the neoplastic process and the concentrations of selected biomarkers of the oxidative damage in rats with implanted prostate cancer cells. It was found that the diet supplementation with selected minerals (zinc, selenium, iron, copper and calcium) affect the occurrence of prostate tumor growth in the examined rats. The intraperitoneal implantation of prostate cancer cells resulted in the occurrence of prostatic adenoma in 71% of the examined rats. In the rats that were additionally supplemented with selenium and with copper, the cancer cell aggregates constituted, respectively, 25% and 38% of the cases. As a result of implantation of cancer cells, the level of biomarkers of lipid peroxidation increased both in the urine and in tissues of the examined animals (rat group without supplementation). No relationship was found between the process of lipid peroxidation due to the supplementation with selenium and copper, and the lower incidence of cancer and the induction of apoptosis. The reduced activity of antioxidative enzymes (catalase, superoxide dismutase and glutathione peroxidase) creates favorable conditions for the formation of cancer cell aggregates, which was shown in the rats whose diet was supplemented with iron. In summary, we conclude that lipid peroxidation represents a fruitful approach to early stage cancer prevention. Supplementation of rats with trace elements correlated with the risk of developing cancer, but the mechanisms of this action is complicated and dose-dependent.

Differences in the pharmacokinetics of flumequine after single and continuous oral administration in non-fasted broiler chickens.

The aim of this study was to determine the influence of feed on the pharmacokinetics of flumequine (FLU) administered to broiler chickens as follows: directly into the crop (10 mg/kg of BW) of fasted (group I/control) and non-fasted chickens (group II), or administered continu- ously with drinking water (1 g/L for 72 h) and with unlimited access to feed (group III). Plasma concentration of FLU was determined by high-performance liquid chromatography with fluo- rescence detection. In group II, a significant decrease in the maximum concentration (Cmax = 2.13±0.7 µg/mL) and the area under the concentration curve from zero to infinity (AUC0→∞ = 7.47±2.41 µg·h/mL) was noted as compared to the control group (Cmax = 4.11±1.68 µg/mL and AUC0→∞ = 18.17±6.85 µg·h/mL, respectively). In group III, the decrease in AUC was signifi- cant only in the first 3 hours (AUC0→3 = 5.02±1.34 µg·h/mL) as compared to the control group (AUC0→3 = 7.79±3.29 µg·h/mL). The results indicate that feed reduced the bioavailability of FLU from the gastrointestinal tract by at least 50% after the administration of a single oral dose. However, continuous administration of FLU with drinking water could compensate for the feed-induced decrease in absorption after single oral dose.