Importance of supply integrity for in vitro fertilization and embryo culture.

The quality of in vitro culture conditions is a key component of a successful clinical embryology laboratory. Many, but not all, supplies used in the embryology laboratory are screened by the supplier with a bioassay. Embryology laboratories use a variety of approaches to verify the quality of mineral oil, protein, and disposables before clinical use; however, a best practice has not been determined. Some laboratories test every supply, even those already screened by the supplier, whereas other laboratories perform as little testing as possible. Despite screening by the supplier, recent reports of embryo toxicity, specifically with mineral oil, highlight that the integrity of the supply system has gaps. This review describes current bioassay quality control testing and discusses how it applies to screening of products with documented lot-to-lot variation.

Alternatives to the carcinogenicity bioassay: in silico methods, and the in vitro and in vivo mutagenicity assays.

IMPORTANCE OF THE FIELD: Carcinogenicity and mutagenicity are toxicological end points posing considerable concern for human health. Due to the cost in animal lives, time and money, alternative approaches to the rodent bioassay were designed based on: i) identification of mutations and ii) structure-activity relationships. AREAS COVERED IN THIS REVIEW: Evidence on i) and ii) is summarized, covering 4 decades (1971 - 2010). WHAT THE READER WILL GAIN: A comprehensive, state-of-the-art perspective on alternatives to the carcinogenicity bioassay. TAKE HOME MESSAGE: Research to develop mutagenicity-based tests to predict carcinogenicity has generated useful results only for a limited area of the chemical space, that is, for the DNA-reactive chemicals (able to induce cancer, together with a wide spectrum of mutations). The most predictive mutagenicity-based assay is the Ames test. For non-DNA-reactive chemicals, that are Ames-negative and mutagenic in other in vitro assays (e.g., clastogenicity), no correlation with carcinogenicity is apparent. The knowledge on DNA reactivity permits the identification of genotoxic carcinogens with the same efficiency of the Ames test. Thus, a chemical mutagenic in Salmonella and/or with structural alerts should be seriously considered as a potential carcinogen. No reliable mutagenicity-based alternative tools are available to assess the risk of non-DNA-reactive chemicals.