Skin sensitization in silico protocol.

The assessment of skin sensitization has evolved over the past few years to include in vitro assessments of key events along the adverse outcome pathway and opportunistically capitalize on the strengths of in silico methods to support a weight of evidence assessment without conducting a test in animals. While in silico methods vary greatly in their purpose and format; there is a need to standardize the underlying principles on which such models are developed and to make transparent the implications for the uncertainty in the overall assessment. In this contribution, the relationship between skin sensitization relevant effects, mechanisms, and endpoints are built into a hazard assessment framework. Based on the relevance of the mechanisms and effects as well as the strengths and limitations of the experimental systems used to identify them, rules and principles are defined for deriving skin sensitization in silico assessments. Further, the assignments of reliability and confidence scores that reflect the overall strength of the assessment are discussed. This skin sensitization protocol supports the implementation and acceptance of in silico approaches for the prediction of skin sensitization.

Impact of lactic acid bacteria on oxidative DNA damage in human derived colon cells.

It is assumed that reactive oxygen species (ROS) play a key role in inflammatory bowel diseases and colon cancer and a number of studies indicate that lactic acid bacteria (LAB) possess antioxidant properties and may prevent these diseases. In the present study, we developed a model which allowed us to investigate the prevention of oxidative DNA damage in human derived colon (HT29) cells by LAB. Furthermore, we investigated if these effects correlate with superoxide (O2(-)) resistance of the strains. The protective properties of 55 strains were monitored in single cell gel electrophoresis (SCGE) assays. After preincubation of the cells with LAB (60 min), oxidative damage was induced by exposure to plumbagin (5.0 microM, 120 min) which releases O2(-) or by hydrogen peroxide (50 microM, 10 min); O2(-) resistance was monitored in plate growth inhibition assays. 25 strains (45%) reduced plumbagin induced DNA migration while only few of them (20%) were protective towards hydrogen peroxide induced damage. The strongest effects (up to 60% reduction of O2(-) induced DNA migration) were observed with representatives of the species Streptococcus thermophilus. The prevention of DNA damage in the colon cells by the bacteria did not correlate with their O2(-) resistance. Additional experiments indicate that the reduction of oxidative damage is only seen with viable bacteria but not with heat inactivated cells and that it takes also place when the colon cells are separated from the LAB by permeable filter membranes indicating that the bacteria release ROS protective factors into the medium. Dose response experiments showed that the protection depends on the concentration of the bacteria; significant effects were observed with titers 3 x 10(6-7)cells/ml. Unexpectedly, we found that a substantial fraction of the strains (13%) induced DNA damage in untreated cells, some of them increased also the effects of the ROS generating chemicals. Preliminary experiments with tetramethylbenzidine (TMB) agar indicate that this phenomenon may be due to release of hydrogen peroxide by the bacteria. Overall, our study shows that the impact of LAB on DNA damage in human derived colon cells is ambivalent; while the majority of strains was protective against oxidative damage some of them induced per se pronounced DNA migration. Since the effects were seen with bacterial concentrations which may be reached in the intestinal tract after consumption of fermented milk products, it is likely that the effects we observed in the present study are relevant for humans.

Polyethylene Glycol Exposure with Antihemophilic Factor (Recombinant), PEGylated (rurioctocog alfa pegol) and Other Therapies Indicated for the Pediatric Population: History and Safety.

Polyethylene glycol (PEG) is an inert, water soluble polymer, used for decades in pharmaceuticals. Although PEG is considered safe, concerns persist about the potential adverse effects of long-term exposure to PEG-containing therapies, specifically in children, following the introduction of PEGylated recombinant factor products used for the treatment of hemophilia. Given the absence of long-term surveillance data, and to evaluate the potential risk, we estimated PEG exposure in the pediatric population receiving PEGylated therapies with pediatric indications administered intravenously or intramuscularly. We used a range of pediatric weights and doses based on prescribing information (PI) or treatment guidelines. PIs and reporting websites were searched for information about adverse events (AEs). For a child weighing 50 kg on the highest prophylactic dose of a FVIII product, the range of total PEG exposure was 40⁻21,840 mg/year; for factor IX (FIX) products, the range was 13⁻1342 mg/year; and for other products, the range was 383⁻26,743 mg/year, primarily as a derivative excipient. No AE patterns attributable to PEG were found for any of these products, including potential renal, neurological, or hepatic AEs. Our analyses suggest the pediatric population has had substantial exposure to PEG for several decades, with no evidence of adverse consequences.

Binding of heterocyclic aromatic amines by lactic acid bacteria: results of a comprehensive screening trial.

Aim of the present study was a comprehensive investigation of the detoxification capacities of lactic acid bacteria (LAB) towards heterocyclic aromatic amines (HCA) formed during cooking of meat. It has been postulated that LAB prevent genotoxic and/or carcinogenic effects of HCA in laboratory rodents and humans via direct binding mechanisms. We measured the removal of the most abundant cooked food mutagens (AalphaC, PhIP, IQ, MeIQx, DiMeIQx) by eight LAB species. From each species, twelve strains were tested in liquid binding experiments with HPLC coupled with coulometric electrode array detection. The highest removal rates were observed with the representatives of the L. helveticus and S. thermophilus groups, which were seven to eight times more effective than L. kefir and L. plantarum. Strong and statistically significant differences were seen in the binding behaviour of the individual amines, the ranking order of detoxification being AalphaC > DiMeIQx > MeIQx > IQ > PhIP. Results of Salmonella/microsome assays with strain TA98 showed that the binding of AalphaC and PhIP to LAB correlates with the reduction of their mutagenic activities. This study may contribute to the development of strategies concerning the adverse health effects of HCA utilizing highly protective LAB for the production of fermented foods.