Cytochrome P450 (CYP)3A4 induction by drugs and pesticides plays a critical role in the enhancement of pyrrolizidine alkaloid (PA) toxicity as it leads to increased formation of hepatotoxic dehydro-PA metabolites. Addressing the need for a quantitative analysis of this interaction, we developed a physiologically-based toxicokinetic (PBTK) model. Specifically, the model describes the impact of the well-characterized CYP3A4 inducer rifampicin on the kinetics of retrorsine, which is a prototypic PA and contaminant in herbal teas.
View Article and Find Full Text PDFThe Fiber Pathogenicity Paradigm (FPP) establishes connections between fiber structure, durability, and disease-causing potential observed in materials like asbestos and synthetic fibers. While emerging nanofibers are anticipated to exhibit pathogenic traits according to the FPP, their nanoscale diameter limits rigidity, leading to tangling and loss of fiber characteristics. The absence of validated rigidity measurement methods complicates nanofiber toxicity assessment.
View Article and Find Full Text PDFRetrorsine is a hepatotoxic pyrrolizidine alkaloid (PA) found in herbal supplements and medicines, food and livestock feed. Dose-response studies enabling the derivation of a point of departure including a benchmark dose for risk assessment of retrorsine in humans and animals are not available. Addressing this need, a physiologically based toxicokinetic (PBTK) model of retrorsine was developed for mouse and rat.
View Article and Find Full Text PDFBackground: The proportionality principle has been broadly used for over 10 years in regulatory assessments of pesticide residues. It allows extrapolation of supervised field trial data conducted at lower or higher application rates compared to the use pattern under evaluation by adjustment of measured concentrations, assuming direct proportionality between the rates applied and the resulting residues. This work revisits the principle idea by using supervised residue trials sets conducted under identical conditions but with deviating application rates.
View Article and Find Full Text PDFThe hepatitis E virus (HEV) can cause acute and chronic hepatitis in humans. Infections with the zoonotic HEV genotype 3, which can be transmitted from infected wild boar and deer to humans, are increasingly detected in Europe. To investigate the spatiotemporal HEV infection dynamics in wild animal populations, a study involving 3572 samples of wild boar and three deer species from six different geographic areas in Germany over a 4-year period was conducted.
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