Allergic Contact Dermatitis to Linalool Hydroperoxides: Pitfalls in the Diagnostic Process-Findings from a Repeated Open Application Test Study.

Background: Increasing trends of oxidized linalool contact allergy have been reported. However, the impact of reactivity and dose in eliciting allergic contact Dermatitis caused by linalool hydroperoxides is insufficiently investigated. Objectives: To perform repeated open application tests (ROATs) using the real-world concentrations of linalool hydroperoxides in patients and control participants. Materials and Methods: Patients who previously had a positive (patients) and a negative (controls) patch test reaction to linalool hydroperoxides 1.0% in petrolatum were patch tested with a dilution series of linalool hydroperoxides preparations and asked to perform ROAT twice daily with 3 concentrations of linalool hydroperoxides creams and a negative control cream for 28 days. The creams contain 44, 140, and 440 PPM of linalool hydroperoxides, representing real-world doses reported in consumer products. Results: Of all 47 participants, 31 were linalool hydroperoxides contact allergy patients, and 16 were controls. One patient had a positive ROAT reaction in the area where cream at the highest concentration of linalool hydroperoxides was applied for 28 days. Conclusions: Repeated exposure to creams containing linalool hydroperoxides at real-life concentrations could rarely elicit an allergic reaction on intact skin after 4 weeks.

A new animal product free defined medium for 2D and 3D culturing of normal and cancer cells to study cell proliferation and migration as well as dose response to chemical treatment.

Cell culturing methods are increasingly used to reduce and replace the use of live animals in biomedical research and chemical toxicity testing. Although live animals are avoided when using cell culturing methods, they often contain animal-derived components of which one of the most commonly used is foetal bovine serum (FBS). FBS is added to cell culture media among other supplements to support cell attachment/spreading and cell proliferation. The safety, batch-to-batch variation, and ethical problems with FBS are acknowledged and therefore world-wide efforts are ongoing to produce FBS free media. Here, we present the composition of a new defined medium with only human proteins either recombinant or derived from human tissues. This defined medium supports long-term culturing/routine culturing of normal cells and of cancer cells, and can be used for freezing and thawing of cells, i.e. for cell banking. Here, we show for our defined medium, growth curves and dose response curves of cells grown in two and three dimensions, and applications such as cell migration. Cell morphology was studied in real time by phase contrast and phase holographic microscopy time-lapse imaging. The cell lines used are human cancer-associated fibroblasts, keratinocytes, breast cancer JIMT-1 and MDA-MB-231 cells, colon cancer CaCo-2 cells, and pancreatic cancer MiaPaCa-2 cells as well as the mouse L929 cell line. In conclusion, we present the composition of a defined medium without animal-derived products which can be used for routine culturing and in experimental settings for normal cells and for cancer cells, i.e. our defined medium provides a leap towards a universal animal product free cell culture medium.