Invitation Paper: The Search for Relevant Short Term Bioassays for Chemical Carcinogens: The Tribulation of a Modern Sisyphus

Abstract

Based on a good correlation between carcinogenicity and mutagenic activity several rapid microbial bioassays for chemical carcinogens have been recently developed. We would like to suggest, that these microbial tests should be followed by bioassays using cultured human cells of the "average" man, and of persons with elevated cancer risk or increased susceptibility to carcinogenic agents. The main objective of using DNA repair (unscheduled uptake of 3HTdR) and DNA fragmentation (shift in sedimentation profiles) of cultured human cells was to design a test system that can simulate conditions found in man and thus provide information relevant to the human population. A trial on 98 different carcinogens, precarcinogens and noncarcinogens showed the suitability of DNA repair synthesis as a rapid, economic and relevant assay for detection of chemical carcinogens. To check the adaptability of DNA repair synthesis of human cells as a bioassay for chemical carcinogens we examined carcinogenic nitrosation products which are formed from the interaction of nitrite and nitrosatable compounds, carcinogenic or mutagenic photosensitizing chemicals, and the effect of complex interactions. Organotropic carcinogens can be detected by measuring DNA fragmentation and DNA repair in various target organs following the in vivo application of chemical carcinogens. The pros and cons of several bioassays and their usefulness in judging a carcinogenic or mutagenic hazard to human populations is discussed.

Cytogenetic and genotoxic effects of zinc oxide nanoparticles on root cells of Allium cepa

“…Among the several higher plants used as test organisms, the species A. cepa has been used as an efficient genetic standard for environmental monitoring, since Levan's introduction of this species as test system [23][24][25].…”

Studies on Cytological Changes Induced by Muriate of Potash in Allium cepa.

“…The Allium cepa root meristem assay is considered widely as a practical reliable system for the screening of environmental mutagens and carcinogens (Fiskesjo 1985, Stich et al 1975. Preliminary studies showed that concentrations above 2000 ppm exerted toxic effects on cells while concentrations below 200 ppm did not produce abnormalities in cell divisions.…”

Detection of Environmental Mutagens Through Plant Bioassays

“…The Allium material is well known and has been used for the study of basic mechanisms as well as for scoring the efects of chemicals. A. cepa (the common onion) has proved to be the most useful and has repeatedly been suggested as a standard test material [40]. The use of A. cepa as a test system was introduced by Levan [41], when the efects of colchicine were investigated.…”