sentence: The PFAA extracts were obtained using our recently developed method to analyze the xenoestrogenic activity of PFAA mixtures at physiologically relevant concentrations and compositions , acquired by extracting PFAAs from human serum followed by analysis of the ER transactivation induced by the PFAA extracts ( F3-W2 ) in an MVLN cell culture assay ( Bjerregaard-Olesen et al. 2015 ) .