Investigation of a Brazilian tannery effluent by means of zebra fish (Danio rerio) embryo acute toxicity (FET) test.

Tannery effluents consist of a complex chemical composition not only limited to primary pollutants, which also require biological detection as these compounds may produce adverse effects. The fish embryo toxicity (FET) test with Danio rerio is an alternative method in hazard and risk assessment for determination of chemical-mediated effects. The aim of this investigation was to use the FET test to detect compounds and consequent effects in Brazilian tannery effluents. Samples were collected from the inlet and outlet of the effluent treatment plant at a tannery located in Restinga, São Paulo, Brazil. The toxicological effects were assessed using FET assay for a period of 144 hr using indices such as (1) coagulation of fertilized eggs, (2) lack of detachment of tail-bud from yolk sac, (3) absence of spontaneous movement, (4) yolk sack edema, (5) malformation of the tail, (6) scoliosis, and (7) deformation of swim bladder in the embryos. Data showed that effluent treatment plant exposure produced acute toxicity in D. rerio embryos as evidenced by coagulation of fertilized eggs in up to 5% of all diluted samples 24 hr post fertilization for inlet effluent samples compared to 100% coagulation for outlet samples. Results demonstrated that these effects may not be attributed to metals, but to other non-detected components, such as dyes, pigments, biocides, carriers, surfactants, or other organic compounds that might be present in these complex mixtures. The use of D. rerio embryos was found to be useful as an additional tool for ecotoxicity testing to assess the potential environmental acute toxicity influence of tannery effluents.

The herbicides trifluralin and tebuthiuron have no genotoxic or mutagenic potential as evidenced by genetic tests.

Brazil has been the largest world consumer of pesticides since 2008, followed by the USA. The herbicides trifluralin and tebuthiuron have been widely applied in agriculture. These herbicides are selective for some plant species, and their use brings various benefits. However, the genotoxic and mutagenic effects of tebuthiuron on non-target organisms are poorly known, and in addition, the effects of trifluralin must be better investigated. Therefore, this study employed genetic tests including the comet assay and micronucleus test to evaluate the genotoxic effects of trifluralin and tebuthiuron on HepG2 cells. In addition, we have used the Ames test to assess the mutagenic effects of the herbicides on the TA97a, TA98, TA100, and TA1535 strains of Salmonella typhimurium. On the basis of the comet assay and the micronucleus test, trifluralin did not cause genetic damage to HepG2 cells. In addition, trifluralin did not impact the tested S. typhimurium strains. Regarding tebuthiuron, literature has shown that this herbicide damaged DNA in Oreochromis niloticus. Nevertheless, we have found that tebuthiuron was not genotoxic to either HepG2 cells or the S. typhimurium strains. Therefore, neither trifluralin nor tebuthiuron exerted genotoxic or mutagenic potential at the tested conditions.

Ecotoxicological risk assessment of the "Acid Black 210" dye.

The "Acid Black 210" dye is one of the most used black dyes by the leather industry. This compound contains three azo groups in its chemical structure, and has been quoted as a non-regulated dye with toxicological concern, since it could generate carcinogenic aromatic amines. The objective of this study was to perform the ecotoxicological risk assessment of this dye through testing its toxicity in vitro and in vivo with the Ames test, the Comet assay, the Daphnia similis test, and the zebrafish embryo acute toxicity test. Moreover, we evaluated the presence of this dye in environmental samples related with a tannery industry. All the tests performed were negative, with the exception of the Ames test with the Salmonella typhimurium TA98 strain, which resulted in a low mutagenic potency. Due to the low concentrations of the "Acid Black 210" dye found in tannery effluents, and the high concentrations where any toxic activity is occasionally described, we concluded that this dye is safe from the ecotoxicological point of view in the areas evaluated and in the light of the current knowledge.

Enantioselective analysis of 4-hydroxycyclophosphamide in human plasma with application to a clinical pharmacokinetic study.

Cyclophosphamide (CY) is one of the most common immunosuppressive agents used in autologous hematopoietic stem cell transplantation. CY is a prodrug and is metabolized to active 4-hydroxycyclophosphamide (HCY). Many authors have suggested an association between enantioselectivity in CY metabolism and treatment efficacy and/or complications. This study describes the development and validation of an analytical method of HCY enantiomers in human plasma by high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) that can be applied to pharmacokinetic studies, filling this gap in the literature. HCY enantiomers previously derivatized with phenylhydrazine were extracted from 200-µL plasma aliquots spiked with antipyrine as internal standard and a mixture of hexane and dichloromethane (80:20, v/v) was used as the extraction solvent. The derivatized HCY enantiomers were resolved on a Chiracel(®) OD-R column using water:acetonitrile:formic acid (55:45:0.2, v/v) as the mobile phase. No matrix effect was observed and the analysis of HCY enantiomers was linear for plasma concentrations of 5-5000ng of each enantiomer/mL plasma. The coefficients of variation and inaccuracy calculated in precision and accuracy assessments were less than 15%. HCY was stable in human plasma after three successive freeze/thaw cycles, during 3h at room temperature, and in the autosampler at 4°C for 24h after processing, with deviation values less than 15%. The method was applied to evaluate the kinetic disposition of HCY in a patient with multiple sclerosis who was pretreated with intravenous racemic CY for stem cell transplantation. The clinical study showed enantioselectivity in the pharmacokinetics of HCY.