Dietrich, Daniel R.
Toxikologische Auswirkungen : Gesundheitsgefährdende Stoffgemische
1999, Dietrich, Daniel R.
Jüngste Beobachtungen wie eine scheinbar vermehrte Krankheitsanfälligkeit der Bevölkerung, verminderte Fruchtbarkeit bei Männern, erhöhte Inzidenzen für Brust-, Prostata-, Leber- und Nierentumore weisen auf die Präsenz von "toxischen" Stoffen in der Umwelt hin.
Interactions of nitromusk parent compounds and their amino-metabolites with the estrogen receptors of rainbow trout (Oncorhynchus mykiss) and the South African clawed frog (Xenopus laevis)
1999, Chou, Ya-Juin, Dietrich, Daniel R.
Nitromusks, musk xylene (MX), musk ketone (MK) and musk moskene (MM) are synthetic fragrances. 4-Amino-MX (4X), 2-amino-MX (2X) and 2-amino-MK (2K) are nitromusk metabolites formed during the sewage treatment process and have been detected in effluent and surface water at concentrations four to 40 times higher than their parent compounds. To date, data to the aquatic toxicity of nitromusk compounds are limited to the parent compounds and the determination of acute and subacute effects in aquatic organisms. No data are available regarding the potential endocrine modulating effects of these compounds and/or their metabolites in aquatic organisms. Therefore, the competitive binding capability of nitromusks and their metabolites to the estrogen receptors (ER) in rainbow trout and xenopus was investigated. No binding of MX, MK and MM to the ER of either species was observed. In contrast, binding to the ER was observed for 4X, 2X and 2K in both species. The IC50 (competitive binding at the ER) of 2X in rainbow trout was 1.3±1.1 mM. In contrast, 4X, 2X and 2K bound to the xenopus ER with an IC50 of 30.8±28.5, 12.9±10.3 and 70.1±88.3 μM, respectively.
Effects of conventional insecticides and insect growth regulators on fecundity and other life-table parameters of Micromus tasmaniae (Neuroptera: Hemerobiidae)
1998, Rumpf, Silke, Frampton, Chris, Dietrich, Daniel R.
Effects of 3 conventional insecticides (methyl parathion, azinphos-methyl, cypermethrin) and 3 insect growth regulators (fenoxycarb, diflubenzuron, and tebufenozide) on life-table parameters of Micromus tasmaniae Walker were determined in adults derived from insecticide-treated larvae. The following parameters were compared with the control: sex ratio, longevity, sterility, and fecundity. Power analysis was used to increase the efficiency and the predictability of the life-table test. Diflubenzuron resulted in a higher proportion female lacewings. Longevity was reduced for females emerging from fenoxycarb- and diflubenzurontreated larvae. Total number of eggs was reduced for diflubenzuron- and fenoxycarb-treated lacewings, as well as the following generation oftebufenozide-exposed lacewings. Daily number of eggs was reduced for the diflubenzuron treatment. Peak egg production was increased for lacewings exposed to azinphos-methyl and was decreased for the following generation of tebufenozide-exposed lacewings. Diflubenzuron treatment resulted in an extended preoviposition period. Oviposition periods were reduced for lacewings treated with fenoxycarb, diflubenzuron or azinphos-methyl as well as for the following generation of the tebufenozide treatment. The time to peak egg production was similar for all treatments. Methyl parathion, cypermethrin, and tebufenozide treatments showed no differences in any of the tested life-table parameters in the 1st generation. In summary, the insect growth regulators fenoxycarb and diflubenzuron had a more severe impact on life-table parameters than the 2 organophosphates and the pyrethroid. In future research, increased attention should be paid to long-term (e.g., the following generation) effects on life-table parameters.
Esterases in the zebra mussel Dreissena polymorpha : activities, inhibition, and binding to organophosphates
1997, Dauberschmidt, Carole, Dietrich, Daniel R., Schlatter, Christian
Cholinesterase activities of Dreissena polymorpha were measured colorimetrically. In homogenates of whole control mussel, activities of 125 ± 29 μmol min -1 kg -1 were found (n = 6). Neither after exposure of Dreissena to organophosphates (thiometon, disulfoton, demeton-S-methyl) nor after addition of demeton-S-methyl (the activated oxygen analogue of thiometon) in vitro was the measured mussel esterase activity inhibited. Esterases of rat, mouse and human tissue showed a 90 100% inhibition. Radiolabelling of the active serine site of esterases in muscle homogenates with 3H-diisopropylfluorophosphate and subsequent separation on polyacrylamide gels revealed similarities as well as differences between rat and mussel esterases. Coomassie-stained muscle proteins of Dreissena showed a different distribution pattern than those of rat. Proteins of rat as well as proteins of mussel with molecular weights between 66 and 97 kDa showed best labelling (highest radioactivity). Proteins with molecular weights greater than 97 kDa were not labelled. Additionally, in Dreissena but not in rat, proteins of around 45 kDa were labelled. The results indicate that the esteratic enzymes in Dreissena were labelled but not inhibited by organophosphates.
The role of alpha2u-globulin in ochratoxin A induced renal toxicity and tumors in F344 rats
1999, Rásonyi, Thomas, Schlatter, Josef, Dietrich, Daniel R.
The mycotoxin ochratoxin A (OTA) was shown to be a potent kidney carcinogen in rats demonstrating a marked sex difference in the response. Compared to female rats, male rats had a 10-fold higher incidence of kidney carcinomas. The objective of this study was to investigate whether this sex difference in tumor response is due to an exacerbation of effect resulting from the interaction of the male rat specific urinary protein α2u-globulin (α2u) with OTA. Male and female rats were treated by oral gavage with OTA (1 mg/kg per day), D-limonene (dL; 1650 mg/kg per day) as a positive control or corn oil for 7 consecutive days. OTA induced severe renal lesions predominantly in the P3 region of the proximal tubules. The lesions consisted of necrotic cells and cell exfoliations. No hyaline droplets were found in the P2 segment following OTA treatment, whereas dL induced the expected accumulation of droplets. The results suggest that OTA induced kidney lesions are in all characteristic points different from the known α2u-nephropathy induced by dL. Based on these experiments the male rat specific protein α2u does not seem to be involved in the mechanism(s) leading to the high tumor incidence observed in OTA exposed male rats.
Toxicity of nitromusks in early lifestages of South African clawed frog (Xenopus laevis) and zebrafish (Danio rerio)
1999, Chou, Ya-Juin, Dietrich, Daniel R.
Musk xylene (MX), musk ketone (MK) and musk moskene (MM) are synthetic nitro-containing fragrances. Due to their inherent lipophilicity and environmental persistence, they are frequently detected in environmental samples and especially in aquatic ecosystems. Despite this, the current environmental toxicity database of nitromusks is limited. Although nitromusks have been shown to accumulate in aquatic organisms, little is known about their potential developmental effects in the respective aquatic species. To investigate the developmental toxicity of these compounds to amphibians and fish, early lifestages of xenopus (Xenopus laevis) and zebrafish (Danio rerio) were exposed to three nitromusks for 96 h to examine the developmental effects of these compounds in the two species. Nitromusk body concentration measurements were carried out in parallel for correlation with potential developmental effects. No increased mortality, malformation or growth inhibition was observed in either species following 96-h exposure to 400 μg/l MX, MK and MM. However, an approximately 20% reduced viability was observed in xenopus larvae when exposed to 400 μg/l MX, MK and MM for 11 days. Xenopus and zebrafish exposed to 10, 153, 871 and 1637 μg/l 14C-MX for 96 h resulted in whole-body concentrations of 0.7±0.1, 11.1±1.1, 38.7±1.9 and 76.3±18.3 μg/g, and 4.3±0.6, 73.3±11.8, 440.0±72.7 and 664.0±47.7 μg/g wet body weight, respectively. Exposure of xenopus larvae to 400 μg/l MX, MK and MM for 11 days, resulted in whole body concentrations (extrapolated from gas chromatographic determinations) of 4700±5000, 1300±300 and 4600±4800 μg/g wet weight for MX, MK and MM, respectively. The latter toxicity results, in conjunction with the fact that the concentrations used for the above experiments were between 400- and 10 000-fold higher than those detected in the environment, suggest that environmental concentrations of nitromusks are not hazardous for early lifestages of fish and amphibians.
Verursachen Stoffgemische in Zukunft gesundheitliche Probleme?
1998, Dietrich, Daniel R.
Die klassische Toxikologie respektive Umwelttoxikologie der Einzelstoffe - mit einem durch Einzelstoffe verursachten Krankheitsbild - wird in Zukunft immer mehr einer Toxikologie der Gemische weichen. Bei diesen Stoffen handelt es sich nicht nur um Industrie- und Agrarprodukte, sondern vielmehr auch um Veterinär- und Humanpharmaka und Stoffe des täglichen Gebrauchs sowie um Naturstoffe. Deshalb ist ein ganzheitlicher Ansatz bei der Erfassung der involvierten Faktoren und der toxikologischen Auswirkungen auf Mensch und Tier erforderlich.