Causation of Oxidative Stress and Defense Response of a Yeast Cell Model after Treatment with Orthodontic Alloys Consisting of Metal Ions.

Misaligned teeth have a tremendous impact on oral and dental health, and the most efficient method of correcting the problem is orthodontic treatment with orthodontic appliances. The study was conducted to investigate the metal composition of selected orthodontic alloys, the release of metal ions, and the oxidative consequences that the metal ions may cause in the cell. Different sets of archwires, stainless steel brackets, and molar bands were incubated in artificial saliva for 90 days. The composition of each orthodontic material and quantification of the concentration of metal ions released were evaluated. Metal ion mixtures were prepared to determine the occurrence of oxidative stress, antioxidant enzyme defense system, and oxidative damage to proteins. The beta titanium alloy released the fewest metal ions and did not cause oxidative stress or protein damage. The metal ions from stainless steel and the cobalt-chromium alloy can cause oxidative stress and protein damage only at high concentrations. All metal ions from orthodontic alloys alter the activity of antioxidant enzymes in some way. The determined amounts of metal ions released from orthodontic appliances in a simulated oral environment are still below the maximum tolerated dose, and the concentrations of released metal ions are not capable of inducing oxidative stress, although some changes in antioxidant enzyme activity were observed at these concentrations.

Kinetics of interaction of Cr(VI) and Cr(III) with serum constituents and detection of Cr species in human serum at physiological concentration levels.

A novel analytical method, based on monolithic convective interaction media (CIM) chromatography coupled to UV and inductively coupled plasma mass spectrometry (ICP-MS) detectors, was developed to investigate the kinetics of interactions of Cr(VI) and Cr(III) with serum constituents, and perform Cr speciation at physiological concentration levels. Cr(VI) was separated from Cr-transferrin (Cr-Tf) and Cr-albumin (Cr-HSA) on a CIM diethylamino (DEAE) column using linear gradient elution from 100% buffer A (50 mM Tris-HCl + 10 mM NaHCO3, pH 7.4) to 60% buffer B (buffer A + 2 M NH4Cl) in 10 min at a flow rate of 1 mL min-1. Good column recovery of separated Cr species (close to 100%) and satisfactory method repeatability (RSDs below 8%) was obtained. Kinetics of interaction of Cr(VI) and Cr(III) with serum constituents were followed after human serum was doubly spiked with enriched 50Cr(VI) and 53Cr(III) solutions, and speciation analysis applied from 5 min up to 48 h after spiking. The results showed that in serum 53Cr(III) rapidly interacted with Tf, while 50Cr(VI) reduction was slow. 48 h after spiking, more than 90% of added 53Cr(III) was bound to Tf and the remaining 10% associated with HSA. About 20% of spiked 50Cr(VI) was still present in serum, while the resulting 50Cr(III) was bound predominantly to Tf. High sensitivity of the developed speciation procedure enabled detection of Cr-Tf complex as the main Cr species in human serum at physiological concentration levels. To the best of our knowledge, Cr-Tf concentrations in serum of unexposed individuals have not been reported yet.

Potentially toxic elements in water, sediments and fish of the Evrotas River under variable water discharges.

Among different stressors like drought, hydro-morphological alterations, and pollution from agricultural activities, nutrients, organic compounds and discharges from wastewater treatment plants (WWTPs), potentially toxic elements (PTE) may also contribute to the overall pollution of the Evrotas River, Greece. Nevertheless, information on pollution of elements in water and sediments in this river is scarcely documented. There is also no information available on the impact of elemental pollution from the aquatic environmental compartments on biota. To fill these gaps, in this study, water, sediment and fish samples were collected from four sampling sites along the Evrotas River under variable flow regimes (July 2015, higher discharge; June 2016, low discharge and September 2016, minimum discharge). Total and dissolved element concentrations in water samples, total and acetic acid extractable contents in sediments, and element concentrations in fish samples were determined by inductively coupled plasma mass spectrometry and significant relationships between samples were established using correlation analysis. The concentrations of PTE (Ni, Cr, Cd, As, Pb, Zn and Cu) in water were generally low, while elevated Ni and Cr contents were found in sediments (up to 150 and 300 mg/kg, respectively), with total Cr concentration in water and sediment being positively correlated. The ecological risk posed by the simultaneous presence of PTE in sediments evaluated by calculating the Probable Effect Concentration Coefficient (PEC-Q), demonstrated that PEC-Qs, which were above the critical value of 0.34, derived mostly from Cr and Ni inputs. Since their mobile sediment fraction was extremely low, Cr and Ni origin is most probably geogenic. The analysis of elements in the target fish species, the Evrotas chub, showed low to moderate PTE concentrations, with Pb being positively correlated with total Pb concentration in water. Moderate Zn concentrations found in fish samples from the Evrotas are possibly derived from pesticides and fertilizers.

Determination of polybrominated diphenyl ethers in human serum by gas chromatography - inductively coupled plasma mass spectrometry.

Polybrominated diphenyl ethers (PBDEs) are flame retardants that are added to a wide range of consumer products. Due to their extensive use in the past, their presence has been documented in multiple environmental compartments and living organisms, including humans. To assess the exposure of humans to PBDEs, a new simple, reliable, and sensitive method was developed for the determination of six PBDE congeners (BDE 28, BDE 47, BDE 99, BDE 100, BDE 153, BDE 154) in human serum by gas chromatography-inductively coupled plasma mass spectrometry (GC-ICP-MS). The PBDEs were extracted from 1 mL ofserum by 30 min of mechanical shaking with formic acid. Subsequently, 2 mL of iso-octane was added and 30 min of mechanical shaking was applied. For clean-up of the extract Florisil column was applied. The analytical method was validated by analysis of human serum standard reference materials SRM 1957 (Non-Fortified Human Serum) and SRM 1958 (Fortified Human Serum). Good agreement of the determined concentrations with those certified was found. The repeatability and reproducibility of the analytical method was within 5.9% and 6.1%, respectively, whereas the limits of detection (LODs) for the PBDEs analysed were between 0.0016 and 0.0039 ng mL-1 wet weight (ww). The feasibility of the method was tested by analysing human serum samples. In this study, the determined concentrations in sera were in a range similar to that of as those reported for certain other European countries.