Biomedical subjects
Publications and source records attributed to R Strobel.
In the Salmonella/microsome test, DNCB was mutagenic for TA100, TA1538, and TA98, whereas SADBE did not induce mutations in the test system. The ability of the compounds to transform BHK cells being able to reproduce in semi-solid agar was investigated. DNCB induced a dose-dependent increase in transformed cells, SADBE did not show this effect.
Transformation of BHK 21 C 13 cells was evaluated by the ability of transformed cells to reproduce in semi solid agar (anchorage independent growth). The in vitro test system was carried out according to Styles with modifications. All compounds were tested with and without metabolic activation (S-9 mix). The results demonstrate the importance of a metabolizing system in this cell transformation assay.
Nine polycyclic aromatic hydrocarbons (PAHs) were investigated by the cell-transformation assay method of Styles. Benzo(a)pyrene [B(a)P], chrysene (CH), 3-methylcholanthrene (3-MC), benz(a)anthracene (BA), benzo(b)fluoranthene [B(b)F], and dibenz(a,h)anthracene (DBA) were tested, including liver homogenate, and showed dose-effect relationships and a more than 2-fold increase of transformation rates at LC50. Due to variations of the test method our results differed quantitatively from the data published by Purchase and Styles. Discrimination between the known carcinogens listed above and the noncarcinogens, phenanthrene (PA) and anthracene (AC), lacking a dose-effect relationship was, however, possible. Benzo(e)pyrene [B(e)P] was regarded as positive although producing only a 2-fold increase in the number of transformed colonies.
2'-(2-Hydroxy-3-propylaminopropoxy)-3-phenyl-propiophenone-hydrochloride (propafenone-HCl, Rytmonorm) was tested for mutagenic activity in the Salmonella microsome system (Ames test) and in mammalian cell systems. Neither in the Ames test (62.5-1000 microgram/plate) nor in the bone marrow cells and spermatogonia of Chinese hamster (injected doses: 1.57, 3.13, 6.27 mg/kg) there is any evidence for an enhancement of mutation frequencies or chromosome aberration rates. Also, the micronucleus rates were in the control range. Under the experimental conditions of this investigations propafenone-HCl was not mutagenic.
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The caffeine derivative 8-ethoxycaffeine (EOC) was tested in 3 different test systems in vitro. Each experiment was carried out with and without S9 mix. Incubation temperatures were 20 and 37 degrees C. (1) In the Salmonella/microsome test, EOC behaved as a pro-mutagen in the Salmonella typhimurium strain TA1535. No mutagenic activity was found in experiments without S9 mix. The influence of temperature was negligible. The mutagenic activity of EOC depended mainly on the mammals used to prepare the S9 fraction and on the agents given to them to induce liver enzymes. (2) EOC did not induce sister-chromatid exchanges in cell cultures, either at 20 or at 37 degrees C. (3) On the other hand, EOC induced chromosomal aberrations when the cells were incubated at 37 degrees C without S9 mix.
Competition experiments were carried out under varying exogenic and endogenic conditions. The genotypes were marked by combinations of two esterase loci, each with two alleles. When genotypes of the line W7 were used, there was no demonstrable influence of the gene blocks marked by the Est-1 locus on the competitive ability at temperatures of 21 and 29 C. However, genotypes carrying the fast allele of the Est-2 locus were favored. At 38 C, the outcome of the competition was reversed. The defined gene blocks showed different effects when interacting with different genetic backgrounds (line M7). Genotypes marked by the slow allele of the Est-2 locus were now favored (21 and 29 C), and even the gene blocks marked by the alleles of the Est-1 locus influenced the genotypes' competitive abilities. Again, the results were partly reversed at 38 C. The results are discussed with regard to the importance of enzyme variants for the genotypic selection value.
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