Biomedical subjects

Nevenka Kozuh Erzen

Publications and source records attributed to Nevenka Kozuh Erzen.

7 recordsLinked to original sources

PubMed2006

Analytical procedure for determination of the time profile of eprinomectin excretion in sheep faeces.

An analytical procedure has been introduced to enable study of the time profile of eprinomectin excretion in sheep faeces. Eprinomectin was extracted from sheep faeces with acetonitrile, the extract was cleaned by solid-phase extraction (SPE), and, after derivatization by reaction with N-methylimidazole, trifluoroacetic anhydride, and acetic acid, eprinomectin was analysed by high-performance liquid chromatography (HPLC) with fluorescence detection. The method has a low detection limit (1.0 ng g(-1) of moist sheep faeces), a low quantification limit (2.5 ng g(-1) of moist sheep faeces), good recovery (in the range 78.8 to 87.1%), and good reproducibility (RSD<10%). The method was used to study the time-profile of excretion of eprinomectin in sheep faeces after a single topical administration of 0.5 mg kg(-1) b.w. of the drug. Because of its good recovery, precision, and sensitivity, the method has also proved applicable to further ecotoxicological studies of eprinomectin.

Animals↗

PubMed2006

Abamectin in the aquatic environment.

Abamectin, widely used as a veterinary anthelmintic, medicine against a variety of animal parasites and insects, can runoff from the sites of application and becomes an aquatic pollutant. The aim of this study was to identify the toxicity of abamectin on bacteria, algae, daphnids, and fish. An extremely high toxicity of avermectin to the survival and reproduction of Daphnia magna was observed in 21-day exposure tests. Zebrafish and the algae Scenedesmus subspicatus are less sensitive to avermectin. The compound is expected to have adverse effects on the aquatic environment due to its high toxicity, even at very low concentrations, to daphnids and to fish.

Aliivibrio fischeri↗

PubMed2006

Abamectin effects on rainbow trout (Oncorhynchus mykiss).

The effect of abamectin (ABM) on rainbow trout (Oncorhynchus mykiss) was studied. The acute toxicity of ABM on rainbow trout was established, following the target 58-h water bath exposure of ABM concentrations from 0.6 to 4.5 microg/l, on the basis of which LD75 (4.0 microg/l) was calculated. The histological changes in organs showed a direct toxicity of ABM for rainbow trout since degenerative changes in brain and kidney and--to a minor extent--in liver were established. The values of the ABM residues in fish muscle tissue with skin were proportional to the exposed concentrations of ABM.

Animals↗

PubMed2006

Time profile of abamectin and doramectin excretion and degradation in sheep faeces.

We studied abamectin and doramectin excretion and their degradation in sheep faeces under field conditions on pasture after a single subcutaneous dose (0.2mg/kg body weight). In the excretion experiment, maximal abamectin concentration (1277 ng/g dry faeces) was detected on day 3, while doramectin concentration showed two peaks (2186 and 1780 ng/g dry faeces on days 2 and 5, respectively). Both avermectins were excreted at approximately the same rate (k=0.23 day(-1) for abamectin and 0.19 day(-1) for doramectin). In the field, a rapid loss of abamectin and doramectin from sheep faeces was seen during the first 32 days after which concentrations remained constant at approximately 77 ng/g and 300 ng/g, respectively. The half life values (DT(50)) for abamectin and doramectin dissipation from sheep faeces were 23 and 22 days, respectively, during the first 32 days. Dissipation of both avermectins was strongly correlated with moisture content of the faeces.

Animals↗

PubMed2005

Degradation of abamectin and doramectin on sheep grazed pasture.

Avermectins are widely used veterinary medicines. They bind strongly to faeces in their non-metabolized form and their half-life in faeces depends on field conditions. There are conflicting data regarding the behaviour of avermectins in the environment. Therefore, we investigated the degradation of abamectin and doramectin on sheep grazed pasture under field conditions in soil, soil-faeces and faeces samples from day 6 to day 70 (abamectin) or to day 50 (doramectin) after sheep treatment. Field conditions were recorded periodically during the experiment. Degradation of abamectin in sheep faeces and in soil-faeces was observed until day 60, with small amounts present in faeces until 70 days post treatment. Because the concentration of abamectin residues in soil was very low on day 6 after treatment, further significant degradation could not be measured. The concentration of doramectin in all analysed matrices decreased rapidly until day 50. It can be concluded that high concentrations of both avermectins were present during the first 20 days after treatment and that field conditions have an important role in degradation of avermectins on grazed pasture of treated animals. Clear identification of the consequences of avermectin exposure and the period of the greatest environmental risk will require further investigations.

Animals↗

PubMed2004

Determination of abamectin and doramectin in sheep faeces using HPLC with fluorescence detection.

An analytical procedure for the determination of abamectin and/or doramectin in sheep faeces has been developed. Avermectins were extracted from sheep faeces with acetonitrile, clean-up using solid phase extraction (SPE) and analysed by high performance liquid chromatography (HPLC) with fl uorescence detection after derivatization with N-methylimidazole.The method has a low detection limit (1.0 ng/g of moist sheep faeces), low quanti fi cation limit (2.5 ng/g of moist sheep faeces), good recovery in the range 66.4-80.8% for abamectin and 67.7-85.5% for doramectin as well as good repeatability (>85%). The method is applicable to the study of the time pro fi le of excretion in sheep faeces and also for ecotoxicological studies of both avermectins.

Animals↗

PubMedDate not supplied

Membrane switch hypothesis. 2. Domain structure of phagocytes in horses with recurrent airway obstruction.

The mechanism of recurrent airway obstruction (RAO) in horses was investigated by measuring the membrane domain structure and oxy-redoxy activity in phagocytes isolated from bronchoalveolar lavage fluid (BAL) and from the blood of healthy and RAO horses by electron paramagnetic resonance (EPR). Differences in the activity of intracellular antioxidant enzymes CAT, GPx, and SOD measured in phagocytes of RAO horses in comparison to healthy horses showed that the phagocytes were affected by oxidative stress. In comparison with polymorphonuclear leukocytes (phagocytes) from the blood of healthy horses the reduction mechanisms in BAL were faster and coincided with the merging of disordered membrane domains, while in horses with RAO the reduction and membrane domain structure remained unchanged. We assume that the merging of lipid domains observed in phagocytes from BAL of healthy horses could promote cluster formation of membrane proteins or ligands, which could trigger the activation process in phagocytes of healthy horses and consequently the physiological response that probably did not happen in phagocytes of RAO horses.

Airway Obstruction↗