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AbstractThis study analyzed the residue depletion kinetics of ivermectin (IVM) in Nelore and crossbred (Nelore x Angus) cattle aiming to compare the profiles between the breeds and evaluate the residue levels at the injection site. IVM 1%, at a dose of 0.2 mg/kg, was administered via the subcutaneous route, and tissue samples were collected on different days post administration for analysis by LC–MS/MS. The results revealed that the detection of the marker residue in conventional matrices such as the liver, perirenal fat, and trapezius muscle (injection site) had relatively high residue concentrations. The maximum residue limit (MRL) was exceeded at the injection site at 21- and 35-days post administration in crossbred and Nelore animals, respectively, with significant variations between animals. This study highlighted significant challenges in accurately determining the pharmacokinetic profile and withdrawal periods of IVM in cattle due to high variability in tissue residue data, particularly at injection sites. The comparison of IVM concentrations between cattle breeds was hindered by high standard errors, emphasizing the need for more rigorous sampling protocols. The results suggest that current guidelines may not adequately account for the erratic depletion kinetics of injectable formulations like IVM, especially at injection sites. Therefore, improving sampling techniques and revising guidelines are essential for accurate residue monitoring and withdrawal period determination. [ABSTRACT FROM AUTHOR]

Cynara scolymus is a plant used both as food as well as medicinal plant worldwide. Cynarin is one of the main active principles of the plant, and it is also present in species such as Echinacea purpurae, which is known to have immunomodulatory activity. Thus, the objective of this study is to evaluate the immune effects of C. scolymus in rats. Rats were treated with 1.0-, 2.0-, or 4.0-g/kg body weight of C. scolymus extract for 28 days. Haemogram, serum biochemistry, lymphoid organs weight, and their cell phenotypes were evaluated. Macrophages and neutrophils oxidative burst, specific humoral immune response, and the delayed-type hypersensitivity (DTH) were studied. No changes in the haemogram, biochemical profile, antibody titers, lymphoid organs, and in their cellularities were observed. An increase in the basal activity of reactive oxygen species from male's macrophage was observed. There was a suppression of the DTH response in both gender when treated with the highest dose of C. scolymus. This study is the first in the literature that revealed an immunosuppressive effect of C. scolymus. We also verified that the doses of artichoke extract here employed did not cause general toxicity. [ABSTRACT FROM AUTHOR]

ABSTRACT Water temperature is a critical environmental parameter that significantly influences fish metabolism. This study assessed the metabolism of florfenicol (FF) in tilapia (Oreochromis niloticus) at water temperatures typical of tropical and subtropical regions. Fish were treated with FF by oral administration of a dose of 10 mg kg−1 bw for 10 consecutive days. Fish fillet, liver, and kidney were sampled during the treatment phase (1, 5, and 10 days) and posttreatment (1, 2, 3, and 5 days after the last FF administration). FF, florfenicol amine (FFA), monochloro florfenicol (FFCl), and florfenicol alcohol (FFOH) were determined in the sampled tissues using a validated LC–LC–MS/MS method. The highest FF, FFA, and FFOH concentrations were determined on day 5 during the treatment phase. For FF, the concentration order is kidney > liver > fillet, while for the metabolites FFOH and FFA, the order is liver > kidney > fillet. In fillet and liver, the concentrations of FFOH were higher than the FFA concentrations, indicating that FFOH was the primary metabolite in these tissues. FFCl was only quantified at concentrations lower than 90 μg kg−1 in all tissues. The results indicated that FF can be readily absorbed and rapidly eliminated in tilapia cultivated in warm water environments. This study revealed FFOH as the primary and most persistent metabolite in tilapia farmed in warm water, followed by FFA. [ABSTRACT FROM AUTHOR]

Embryonic stem cells (ESC) are widely used due to their unlimited capacity of differentiation into different cell lineages, which makes ESC a viable choice as a toxicology test model. Toxicological analysis using embryonic stem cells (ESC) has become an important tool in toxicology procedures. Regarding toxicological analysis methods, flow cytometry (FC) is one technique designed to detect and evaluate cells in suspension, for example, ESC suspension, thus making possible to study different biological, physical, and/or chemical characteristics of cells. Thus, FC can be very useful for cell toxicology and tumorigenic analyses.