Toxicity and magnetometry evaluation of the uptake of core-shell maghemite-silica nanoparticles by neuroblastoma cells.

Nanoparticle uptake by cells is a key parameter in their performance in biomedical applications. However, the use of quantitative, non-destructive techniques to obtain the amount of nanoparticles internalized by cells is still uncommon. We have studied the cellular uptake and the toxicity of core-shell maghemite-silica magnetic nanoparticles (MNPs), with a core diameter of 9 nm and a shell thickness of 3 nm. The internalization of the nanoparticles by mouse neuroblastoma 2a cells was evaluated by sensitive and non-destructive Superconducting Quantum Interference Device (SQUID) magnetometry and corroborated by graphite furnace atomic absorption spectroscopy. We were thus able to study the toxicity of the nanoparticles for well-quantified MNP uptake in terms of nanoparticle density within the cell. No significant variation in cell viability or growth rate was detected for any tested exposure. Yet, an increase in both the amount of mitochondrial superoxide and in the lysosomal activity was detected for the highest concentration (100 µg ml-1) and incubation time (24 h), suggesting the onset of a disruption in ROS homeostasis, which may lead to an impairment in antioxidant responses. Our results validate SQUID magnetometry as a sensitive technique to quantify MNP uptake and demonstrate the non-toxic nature of these core-shell MNPs under our culture conditions.

Sublethal effects induced by captopril on Cyprinus carpio as determined by oxidative stress biomarkers.

To our knowledge, this is the first study to evaluate captopril-induced oxidative stress in fish, and specifically in the common carp Cyprinus carpio. At present, very few studies in the international literature evaluate the sublethal effects of captopril on aquatic organisms such as fish, and available ones focus on determination of median lethal concentration in crustaceans and algae. Also, studies evaluating these effects do not make reference to the mechanism of action of this pharmaceutical or its toxicokinetics. This limits our knowledge of the characterization of the sublethal effects of this medication and of its potential ecological impact. The present study aimed to evaluate the sublethal effects induced by three different concentrations of captopril, on C. carpio), by determination of activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), as well as indicators of cellular oxidation: hydroperoxide content (HPC), lipid peroxidation (LPX) and protein carbonyl content (PCC). Specimens were exposed for 12, 24, 48, 72 and 96h to three different captopril concentrations: 1µgL-1, 1mgL-1 and 100mgL-1 (the first one has been detected environmentally, the other two have been associated with diverse toxic effects in aquatic species), and brain, gill, liver, kidney and blood samples were evaluated. Significant increases in HPC and LPX were observed mainly in kidney and gill, while PCC also increased in brain. Modifications were found in the activity of SOD (mostly in kidney, brain and blood), CAT (all organs) and GPx (kidney and gill). In conclusion, captopril induces oxidative stress in C. carpio.

Effect of amoxicillin exposure on brain, gill, liver, and kidney of common carp (Cyprinus carpio): The role of amoxicilloic acid.

Amoxicillin (AMX) is one of the most commonly prescribed antibiotics around the world due to its broad-spectrum activity against different bacterial strains as well as its use as a growth promoter in animal husbandry. Although residues of this antibacterial agent have been found in water bodies in diverse countries, there is not enough information on its potential toxicity to aquatic organisms such as the common carp Cyprinus carpio. This study aimed to evaluate AMX-induced oxidative stress in brain, gill, liver and kidney of C. carpio. Carp were exposed to three different concentrations of AMX (10 ng/L, 10 µg/L, 10 mg/L) for 12, 24, 48, 72, and 96 h, and the following biomarkers were evaluated: lipid peroxidation (LPX), hydroperoxide content (HPC), protein carbonyl content (PCC) and activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Amoxicillin and its main degradation product amoxicilloic acid (AMA) were determined by high performance liquid chromatography coupled with electrochemical detection and UV detection (HPLC-EC-UV). Significant increases in LPX, HPC, and PCC (P < 0.05) were found in all study organs, particularly kidney, as well as significant changes in antioxidant enzymes activity. Amoxicilloic acid in water is concluded to induce oxidative stress in C. carpio, this damage being highest in kidney. The biomarkers used are effective for the assessment of the environmental impact of this agent on aquatic species. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1102-1120, 2017.

Comparative validations of non-aqueous capillary electrophoresis and high-performance liquid chromatography methods for the simultaneous determination of histamine H2 receptor antagonists in human urine.

This paper reports a previously optimised method based on non-aqueous capillary electrophoresis (NACE) using UV detection for the separation and simultaneous determination of cimetidine (CIM), ranitidine (RAN), roxatidine (ROX), nizatidine (NIZ) and famotidine (FAM) in human urine. Separation is performed at 25°C and at a separation voltage of 15kV. Methanol containing 10mM ammonium acetate and 0.2% acetic acid was used as background electrolyte, and detection at 214nm. These conditions allow the five analytes to be separated within 4min. In addition in the present paper a HPLC method using diode-array as well as detector, was proposed as standard analytical method, which chromatography conditions were following: a mobile phase consisting of 80:20 20mM phosphate buffer (pH 7.5)/acetonitrile, and using 1mLmin-1 as flow rate of the mobile phase. Detection limits were evaluated on the basis of baseline noise and were establishing between 8 and 15µgL-1 for NACE and between 16 and 162µgL-1 for HPLC. The methods showed good precision with overall intra- and inter-day variations of 0.5-2.0% and 0.7-3.8%, respectively. Finally the proposed methods were successfully applied to the screening determination of the analytes in human urine, with recoveries between 97 and 105%, being able the use as pharmacokinetic data in clinical urine samples.

Micellar electrokinetic chromatography method for the determination of sulfamethoxazole, trimethoprim and their main metabolites in human serum.

A complete analytical procedure, including sample clean-up and a micellar electrokinetic chromatographic method, is presented for the determination of sulfamethoxazole, trimethoprim, and their main metabolites by using 20 mmol L(-1) borate buffer (pH 9.3), 25 mmol L(-1) sodium dodecylsulfate, and 5% v/v acetonitrile as electrolyte. The separation was carried out at 30 kV and 20 degrees C in a fused silica capillary (60.2 cm x 75 microm inner diameter) fitted with a window in the capillary cartridge of 100 x 800 microm. The detector response was linear from the limit of quantification to 3 mg L(-1) for the individual components. The limits of quantification ranged from 0.13 up to 0.24 mg L(-1). The method was applied to human serum, previously spiked at different concentrations of all the analytes, and recoveries between 95% and 108% were obtained.