functions in order to calculate BioTEQ values in the EROD ass this was done likewise for the calculation of GeneTEQs. Rapamycin Afterwar at certain effect levels EC x reference curves were interpolated and delogarithmized . Final EC x values of the reference were divided by the corresponding EC x reference values: GeneTEQ x EC x /EC x reference to different exposure times and effect levels . In additi effects of selected sediment extracts in theet assay were used for the calculation of GeneTEQs in order to demonstrate the applicability of this concept to environmental samples well known t.ntain aplex mixture of chemicals causing genotoxic effects. 3 Cytotoxicity of pure substances and extracts CPP and DMNA did not exert more than 0 cytotoxicity in the neutral red assay within the range of concentrations tested .
In contra for M MN M NQO and the sediment extrac NR 0 , NR 5 and NR 0 values could be determined . Genotoxicity of MNNG After 4 h and 8 h of exposu MNNG showed a clear concentration “response relationship in theet assay . For 4 h and 8 h of exposu the LOECs for tail moment Honokiol inhibitor could be estimated at 5 mg L , respectively. At the highest test concentration of 2 mg L , induction factors of and could be calculated after 4 and 8 h of exposu respectively. For the calculation of different EC values of MNN the logarithmized concentration “response functions after 4 h as well as 8 h of exposure were taken. CDIs for MNNG using tail moment and percent tail DNA are given in Tables and .
Among the test substances select MNNG caused the strongest DNA fragmentation rates and the clearest Xanthone 90471 concentration “response relationship after 4 h and 8 h of exposure without interference buy Honokiol of cytotoxicity. The genotoxicity of MNNG towards sh cells has been well documented: Nacci tested mg L MNNG in primary cultures of hepatocytes from American ounder using theet assay. 4 The highest concentration caused tail length increases greater than sixfold over control values. In another stu strong effects and a clear concentration “response relationship were found in hepatocytes and blood cells from brown trout after in vitro exposure to . mg L MNNG. 5 As far as these sh cell types can bepar literature data conm the results of the present study.
Table Concentration ranges of the genotoxins and Danube River sediment extracts tested in the neutral red assay and theet assay Results and discussion Neutral red assayet organizing center assay The aim of the present study was to identify a reference substance suitable for a standardizedparative assessment of genotoxicity exerted by chemicals and environmental samples. For this Minimum/ Test substance m g L Maximum/ mg L Minimum/ m g L Maximum/ mg L purpo several directly and indirectly acting genotoxic pure substances were selected on the basis of their genotoxic potential known from tests with mammalian systems. In order to identify the most suitable substan the concentration “response relationships of these substances were established using theet assay with the sh cell line RTL . Analogously to the BioTEQ 8 and the FELTEQ concepts 5 in the assessment of cytochrome inducti GeneTEQs were calculated with respect .