Our results are in agreement with the in vitro data concerning the extensive binding of oxaliplatin to plasma proteins and RBCs. They also reveal a strong negative correlation between free drug plasma availability and renal function, with a corresponding positive correlation between clearance of the plasmatic platinum and renal function. Thus, renal impairment entails a greater overall exposure to platinum in the plasma. However, this study failed to elicit any relationship between moderate renal impairment and the acute toxicity associated with oxaliplatin.

No abstract

The main object of our study was to investigate whether the resazurin metabolism assay is a sensitive surfactant and alcohol toxicity test in isolated pig cornea and to compare this recently developed fluorometric assay with the data collected in the eye irritation reference chemical data bank. Resazurin is a substrate that changes color in response to metabolic activity. Isolated pig corneas were immersed for 10 min in surfactants and alcohol irritant solutions. After incubation, resorufin fluorescence was read and corneal viability was assessed. This corneal viability was compared with the maximal modified average score published in the report of ECETOC. This assay highlighted different concentration-dependent irritation potentials of the three surfactants tested, and the same results were obtained with corneas treated with the alcohols. We observed that the degree of surfactant- and alcohol-induced decrease in corneal viability, using the resazurin reduction test, was correlated with the in vivo irritancy measurements as determined by the Draize test and scored with the Modified Maximum Average Score (MMAS). This assay allowed us to classify the ocular irritancy of the tested surfactants and alcohols in the same ranking order as the Draize classification. Corneal viability measurement can be used as a potential alternative for the toxicological assessment of surfactants and alcohols. The nontoxic, nonradioactive resazurin metabolism assay allows rapid assessment of many samples with simple equipment and at reduced cost for continuous monitoring of corneal viability. This assay seems to be suitable as a toxicological screening test for eye irritation determination.

In China, cantharidin has been reported to be active against various human cancers, but with severe side effects such as nephrotoxicity. In order to reduce this toxicity, its demethylated analogue nor-cantharidin has been synthesized and used in cancer therapy, but with only few data regarding safety assessment. The aim of this study was to compare the in vitro effects of cantharidin and nor-cantharidin on renal toxicity and on inflammatory events associated with tumoural process where protein phosphatases could be involved (energy status, prostanoid production, glutathione and nitrite contents) on RAW 264.7 and LLC-PK 1 cells. In macrophages, both cantharidin and nor-cantharidin decreased cell viability, in a concentration-and time-dependent manner. However, IC 50 was lower with cantharidin than with norcantharidin. These two drugs significantly decreased the ATP level after 24 hr incubation. However, ATP decreased much more with cantharidin (up to 4 times) than with nor-cantharidin. When control macrophages were activated with lipopolysaccharideπinterferon-g for 24 hr a significant increase in nitrite content and in prostanoids were observed. Addition of either drug decreased nitrite generation and prostanoids, however these decreases were greater with cantharidin than with nor-cantharidin. In LLC-PK 1 cells, incubated with either cantharidin or nor-cantharidin, our results show significant differences between the two drugs, similar to those observed in peritoneal macrophages, except for GSH content with opposite variations in both cells. We provide a better understanding of the various mechanisms of cantharidin side effects, allowing an easier comparison with nor-cantharidin which could be an attractive therapeutic potential in cancer chemotherapy in western countries.

No abstract

Background: Three-dimensional culture or human corneal equivalents for safety testing are difficult to investigate with classic cytometric or biochemical methods. So a fluorometric method is proposed using resazurin probe. Methods: Absorbance and fluorescence spectra of the oxidized and reduced forms of resazurin were performed to determine optimal measurement conditions. More than 100 enucleated porcine eyes were used for this experiment. Twelve corneas were immersed in resazurin solution and fluorescence was measured hourly from 1 to 10 h. Ninety benzalkonium chloride-treated corneas and control corneas were used as toxicity controls, and corneal viability was compared with in vivo rabbit eye irritation. Results: After analysis of spectra, the optimal measurement condition of resazurin metabolism proved to be a fluorescence measurement using 570 nm excitation wavelength and 590 nm emission wavelength. The reduction of

FK506 and cyclosporin A (CsA) are two potent immunosupressants with similar toxicity profile. Nephrotoxicity is the main adverse effect of both compounds. The aim of this study is to compare the in vitro nephrotoxic effects on renal epithelial cell line LLC-PK1 by measuring cell viability and energy status as evaluated by concentrations of ATP and ATP metabolites. Cell viability (expressed as IC50 was assessed via thiazolyl blue (MTT) assay after incubation for 4-24 h with FK506 or CsA. ATP and its metabolites were determined by HPLC after 4 and 6 h incubation with FK506 or CsA alone at the respective IC50. Both FK506 and CsA decreased cell viability to similar extents, in a dose- and time-dependent manner. After 4 h incubation, both drugs decreased ATP levels (-25%) and increased uric acid levels. However, the latter percentage increase was twofold higher with CsA (18%) than with FK506 (9%). The energy charge, calculated according to levels of adenine nucleotides, was decreased by 10% in FK506-treated cells and by 27% in CsA-treated cells. At the end of 6-h incubation, FK506-treated cells maintained ATP levels coupled with energy charge at near control levels whereas the levels were 32% lower in CsA treated cells. Compared to the 4 h-incubation, the increase in uric acid was similar for FK506 but was doubled with CsA. The decrease in cell integrity and ATP depletion induced by CsA in LLC-PK1 cells was only transiently observed with FK506. By preserving energy status, FK506 leads to fewer metabolic disturbances than CsA in the renal epithelial cell line LLC-PK1, demonstrating a minor potential nephrotoxicity.

No abstract