2-Hydroxypyridine N-Oxide is not genotoxic in vivo.

2-Hydroxypyridine N-oxide (HOPO) is an important coupling reagent used in pharmaceutical synthesis. Our laboratory previously reported HOPO as equivocal in the Ames assay following extensive testing of multiple lots of material. Given the lack of reproducibility between lots of material and the weak increase in revertants observed, it was concluded that it would be highly unlikely that HOPO would pose a mutagenic risk in vivo.

2-Hydroxypyridine-N-oxide (HOPO): Equivocal in the ames assay.

2-Hydroxypyridine-N-oxide (HOPO) is a useful coupling reagent for synthesis of active pharmaceutical ingredients. It has been reported to be weakly mutagenic in the Ames assay (Ding W et al. []: J Chromatogr A 1386:47-52).

Phenolphthalein induces centrosome amplification and tubulin depolymerization in vitro.

Aneuploidy is a major cause of human reproductive failure and plays a large role in cancer. Phenolphthalein (PHT) induces tumors in rodents but its primary mechanism does not seem to be DNA damage. In heterozygous TSG-p53(®) mice, PHT induces lymphomas and also micronuclei (MN), many containing kinetochores (K), implying chromosome loss (aneuploidy).

Development and validation of an in vitro micronucleus assay platform in TK6 cells.

The Organization for Economic Co-operation and Development (OECD) has recently adopted Test Guideline 487 (TG487) for conducting the in vitro micronucleus (MNvit) assay. The purpose of this study is to evaluate and validate treatment conditions for the use of p53 competent TK6 human lymphoblastoid cells in a TG487 compliant MNvit assay. The ten reference compounds suggested in TG487 (mitomycin C, cytosine arabinoside, cyclophosphamide, benzo-a-pyrene, vinblastine sulphate, colchicine, sodium chloride, nalidixic acid and di(2-ethylhexyl)phthalate and pyrene) and noscapine hydrochloride were chosen for this study.

Report on stage III Pig-a mutation assays using N-ethyl-N-nitrosourea-comparison with other in vivo genotoxicity endpoints.

N-Ethyl-N-nitrosourea (ENU) was evaluated as part of the Stage III trial for the rat Pig-a gene mutation assay. Groups of six- to eight-week-old male Sprague Dawley (SD) or Fischer 344 (F344) rats were given 28 daily doses of the phosphate buffered saline vehicle, or 2.5, 5, or 10 mg/kg ENU, and evaluated for a variety of genotoxicity endpoints in peripheral blood, spleen, liver, and colon.