Jernej Kužner

Factors influencing dissipation of avermectins in sheep faeces

Factors influencing fate of avermectins (abamectin, doramectin) in faeces of treated sheep were investigated under different experimental conditions. In the laboratory, concentrations of both avermectins were declined in homogenised faeces of treated animals until day 14 of exposure, regardless of experimental conditions. After that day, no significant decrease in concentrations was observed till the end of the experiment. Established DT(50) did not exceed 9 days. In the karst pasture, an average DT(50) of 27 days was established for abamectin and 23 days for doramectin in natural faeces of treated sheep. In the compost mixture, doramectin concentration was decreased by 38.9+/-2.6% during 21 days of the thermophilic phase of composting. Therefore, DT(50) was not established. A possible influence of moisture content of sheep faeces on concentrations of avermectins was observed.

Normothermic and hypothermic models for studying the deleterious effects of hypoxia-reoxygenation on EDHF-mediated relaxation in isolated porcine coronary arteries

INTRODUCTION The vasomotor response of the coronary artery is altered by hypoxia-reoxygenation (H-R) induced damage. The aim of our study was to compare and evaluate normothermic and hypothermic models which are suitable for future drug studies of vasoprotective action against H-R injury. METHODS Porcine coronary arterial rings were isolated and placed in Krebs-Henseleit (K-H) solution. Rings were exposed to normoxic conditions (control group) and two different H-R conditions: the first induced by a 95% N(2)-5% CO(2) gas mixture (40- and 60-min hypoxia) in a normothermic protocol, and the second induced by hypothermic (4 degrees C) hypoxia-reoxygenation in an air-tight beaker filled with K-H solution (24- and 48-hours hypoxia). Reoxygenation was applied by introducing K-H solution aerated with a 95% O(2)-5% CO(2) mixture under normothermic (37 degrees C) conditions. To test the EDHF-mediated relaxation by substance P, rings were first incubated in L-NNA, nitric oxide synthase inhibitor, and indomethacin, cyclooxygenase inhibitor, and then pre-contracted with thromboxane analogue U-46619. Analysis of the maximum relaxation of the arterial rings was performed by one-way ANOVA, followed by Bonferronis post-test. RESULTS Distal segments of the coronary artery responded faster to contraction induced by U-46619 and were relaxed by substance P to a greater extent than proximal segments. Maximal relaxations of arterial rings induced by a 10 nM solution of substance P were significantly reduced (p<0.001) from the values for normoxic rings (81.0+/-1.0%, n=30) after 40-min H-R (50.5+/-5.3%, n=30), 60-min H-R (32.1+/-3.5%, n=30), 24-hours hypothermic H-R (56.0+/-2.3%, n=30) and after 48-hours hypothermic H-R (38.5+/-5.1%, n=30). CONCLUSIONS The model employing 40-min normothermic H-R is as effective as 24-hours hypothermic H-R, and 60-min normothermic H-R as 48-hours hypothermic H-R for studying the deleterious effects of H-R on EDHF-mediated relaxation.

The development of the method for the determination of terbinafine in cat's plasma and hair.

Abstract Clinical investigations of terbinafine indicate its high treatment activity against infections by several dermatophytes. Its efficiency was tested also in the treatment of microsporosis in cats. The distribution of terbinafine in cat’s plasma and hair is important for the identification of the drug efficiency. A fast and reliable reversed-phase high performance liquid chromatographic method with appropriate sample preparation has been developed.Reliability, good reproducibility and low detection limit (LOD 0.25 ng/ml) of the method enable determination of terbinafine in hair and also in plasma of cats infected with Microsporum canis treated by Lamisil® tablets.