Activity

One of the most challenging areas in regulatory science is assessment of the substances known as UVCB (unknown or variable composition, complex reaction products and biological materials). Because the inherent complexity and variability of UVCBs present considerable challenges for establishing sufficient substance similarity based on chemical characteristics or other data, we hypothesized that new approach methodologies (NAMs), including in vitro test-derived biological activity signatures to characterize substance similarity, could be used to support grouping of UVCBs. We tested 141 petroleum substances as representative UVCBs in a compendium of 15 human cell types representing a variety of tissues. Petroleum substances were assayed in dilution series to derive point of departure estimates for each cell type and phenotype. Extensive quality control measures were taken to ensure that only high-confidence in vitro data were used to determine whether current groupings of these petroleum substances, based largely on the manufacturing process and physico-chemical properties, are justifiable. We found that bioactivity data-based groupings of petroleum substances were generally consistent with the manufacturing class-based categories. We also showed that these data, especially bioactivity from human induced pluripotent stem cell (iPSC)-derived and primary cells, can be used to rank substances in a manner highly concordant with their expected in vivo hazard potential based on their chemical compositional profile. Overall, this study demonstrates that NAMs can be used to inform groupings of UVCBs, to assist in identification of representative substances in each group for testing when needed, and to fill data gaps by read-across.Evaluating stress in laboratory animals is a key principle in animal welfare. Measuring corticosterone is a common method to assess stress in laboratory mice. There are, however, numerous methods to measure glucocorticoids with differences in sample matrix (e.g., plasma, urine) and quantification techniques (e.g., enzyme immunoassay or radioimmunoassay). Here, the authors present a mapping review and a searchable database, giving a complete overview of all studies measuring endogenous corticosterone in mice up to February 2018. For each study, information was recorded regarding mouse strain and sex; corticosterone sample matrix and quantification technique; and whether the study covered the research theme animal welfare, neuroscience, stress, inflammation, or pain (the themes of specific interest in our consortium). Using all database entries for the year 2012, an exploratory meta-regression was performed to determine the effect of predictors on basal corticosterone concentrations. Seventy-five studies were included using the predictors sex, time-since-lights-on, sample matrix, quantification technique, age of the mice, and type of control. Sex, time-since-lights-on, and type of control significantly affected basal corticosterone concentrations. The resulting database can be used, inter alia, for preventing unnecessary duplication of experiments, identifying knowledge gaps, and standardizing or heterogenizing methodologies. These results will help plan more efficient and valid experiments in the future and can answer new questions in silico using meta-analyses.The purpose of this study was to establish an infection model of Galleria mellonella larvae as an alternative in vivo model for biofilm-associated infections on stainless steel and titanium implants. Salinosporamide A research buy First, the model was established with bacteria-free implants to evaluate the biocompatibility of implants in the larvae. Titanium or stainless steel implants were implanted without any adverse effects over the entire observation period of 5 days compared to controls. Then, stainless steel and titanium implants pre-incubated with Staphylococcus aureus were implanted into the larvae to mimic biofilm-associated infection. For both materials, pre-incubation of the implant with S. aureus led to significantly reduced survival of the larvae compared to bacteria-free implants. Survival rates of the larvae could not be improved in this biofilm infection situation by the addition of gentamicin, whereas gentamicin could significantly improve the survival of the larvae in case of planktonic infection of the larvae with S. aureus without an implant, confirming the typical characteristics of reduced antibiotic susceptibility of biofilm infections. Additionally, biofilm formation and various stages of biofilm maturation were confirmed by surface electron microscopy and by measuring gene expression of biofilm-related genes with the pre-incubated implant, which showed strong biofilm formation and upregulation of autolysin (atl) and sarA genes. In conclusion, G. mellonella can be used as an alternative in vivo model to study biofilm-associated infections on stainless steel and titanium implants, which may help to reduce animal infection experiments with vertebrates in the future.Intra-host analysis of SARS-CoV-2 genomic sequences identified two viral haplotypes that comprised of three genetically linked mutations from the respiratory and intestinal tracts of a patient with COVID-19. Spatiotemporal data suggest that this patient initially had dual-infection of two SARS-CoV-2 variants, which subsequently re-distributed into the two systems.The article reports on the development of an efficient, robust and sensitive HPLC-DAD method for the simultaneous determination of five fluoroquinolone-based antimicrobial drugs, namely ciprofloxacin, moxifloxacin, norfloxacin, ofloxacin and pefloxacin in both aquatic and tablet formulations. The robustness of the high-performance liquid chromatography with diode-array detection (HPLC-DAD) method has been evaluated through the concepts of quality-by-design (QbD) and full factorial design of experiments (DoEs), using a Minitab 17 statistical tool. The proposed method offers sequential separation with well-defined peak shape and resolution, and has also been evaluated by following international council for harmonization (ICH) pharmaceutical guidelines. A linear signal response has been achieved for the target fluoroquinolones (FQ) drugs in the concentration range of 45-20,000 ng/mL, with an average correlation coefficient (r2) value of 0.9997, and a data precision and accuracy range of 99.3-100.9%, with an RSD value of ≤0.