Biomedical subjects

D J Letinski

Publications and source records attributed to D J Letinski.

3 recordsLinked to original sources

PubMed2006

Assessing the aquatic hazard of commercial hydrocarbon resins.

Hydrocarbon resins are used to modify polymer products to achieve desired functional properties for a diverse range of products. These complex hydrocarbon-based mixtures are typically poorly soluble in water. However, resins may leach lower-molecular-weight monomers or impurities upon contact with water, thus posing a potential hazard to the aquatic environment. The bioavailability and toxicity of leachable constituents of four solid and three liquid resins were evaluated by analyzing water-accommodated fractions prepared with each resin, using biomimetic solid phase microextraction (SPME) techniques. Liquid resins exhibited concentrations of bioavailable constituents that were sufficiently elevated to cause acute toxicity to the aquatic organism Daphnia magna. All solid resins exhibited lower bioavailable concentrations of leachable constituents that were unlikely to pose an aquatic toxicity concern. Since observed toxicity of both resin types was generally consistent with bioavailable concentrations determined using SPME fiber measurements, it is concluded that this approach provides a convenient in vitro screening tool that can help reduce the use of animal testing in environmental hazard assessment of complex hydrocarbon-based substances.

Animal Testing Alternatives↗

PubMed2005

Hazard evaluation of diisononyl phthalate and diisodecyl phthalate in a Japanese medaka multigenerational assay.

Reproductive and developmental effects of diisononyl phthalate (DINP) and diisodecyl phthalate (DIDP) were evaluated in a Japanese medaka (Oryzias latipes) multigeneration protocol. Each phthalate was administered via fish flake diets at a concentration of 20 microg/g (1 microg/g fish/day). Two controls were included, untreated and acetone carrier. The F(0) and F(1) generation adults were reared to sexual maturation and the test was ended prior to sexual maturation of the F(2) generation. Biochemical, individual, and population parameters were evaluated: testosterone metabolism, 7-ethoxyresorufin-o-deethylase (EROD) activity, survival, development, growth, gonadal-somatic index, histopathology, sex ratio, and fecundity. Male fish showed a two-fold induction of several testosterone metabolites in the DINP-treated group compared to the untreated control but not the acetone control. In a similar manner, in female fish only the DIDP-treated group expressed greater testosterone hydroxylase activity. There were neither sex- nor treatment-related differences in the results from the EROD assay. A statistically significant transient delay in red blood cell pigmentation was observed. The male-to-female ratio was consistent across treatments and the phenotypic and histological gender classifications were in agreement. Egg production was not significantly different among treatment groups. Neither phthalate elicited an effect on reproduction or development at various levels of biological organization.

Animals↗

PubMed2000

Assessing the aquatic toxicity of complex hydrocarbon mixtures using solid phase microextraction.

Assessing the ecotoxicity of hydrocarbon mixtures is complicated by the complex nature of these mixtures. Traditional analytical methods for characterizing hydrocarbon contamination are not good predictors of potential ecotoxicity because these methods fail to characterize the bioavailability of individual hydrocarbon components. Recent research indicates that hydrocarbons act by a common narcotic mode of action and that ecotoxicity occurs when the molar concentration in organism lipid exceeds a critical threshold. Since the ecotoxicity of narcotic mixtures appears to be additive, ecotoxicity thus depends upon the partitioning of individual hydrocarbons from the environment to lipids and the total molar sum of individual hydrocarbons in lipids. These insights have led previous investigators to advance the concept of 'biomimetic' extraction as a novel analytical tool for assessing narcosis-type or 'baseline'. Drawing from this earlier work, a simple method to quantify bioavailable petroleum hydrocarbons (BPHs) in hydrocarbon-contaminated aqueous and soil/sediment samples was developed. The proposed method combines the essential features of biomimetic extraction for simulating the bioconcentration process with the analytical advantages of solid phase microextraction (SPME). The procedure for determining BPH involves two steps. The sample is first equilibrated with a SPME fiber that serves as a surrogate for organism lipids. The total moles of hydrocarbons that partition to the SPME fiber is then quantified using GC/FID. The capability of this method to predict ecotoxicity was assessed by comparing BPH measurements for hydrocarbon contaminated aqueous samples to corresponding toxicity test results for rainbow trout. Results indicate that BPH analyses correlate to the observed acute toxicity. Consequently, BPH analyses offer a promising, cost-effective screening tool for predicting aquatic toxicity of complex hydrocarbon mixtures.

Animals↗