Co and Cr accumulation in hair after metal-on-metal hip resurfacing arthroplasty

Background: Currently, it is unclear whether Co and Cr levels are persistently elevated in the body after hip resurfacing arthroplasty (HRA). This study aimed to evaluate Co and Cr levels in the body after HRA using hair as samples. Methods: Among 22 patients who had metal‐on‐metal HRA (m‐o‐m group) using the DePuy ASR system, scalp hair of 1.5 cm in length and 2 g in weight was collected before and at 6 and 12 months after surgery. Inductively coupled plasma‐mass spectrometry (ICP‐MS) was used to detect Co and Cr levels in the scalp hair. Another 22 patients with total hip replacements were randomly selected from a similar age range as controls (m‐o‐p group). Metal levels in hair were detected with multiple measurements and analysed by repeated measures analysis of variance. Results: Both Co and Cr levels were significantly increased in the m‐o‐m group after surgery compared with those in the m‐o‐p group (P < 0.01). Co levels at 6 months post‐operatively were 12‐fold those before surgery, and Co levels 12 months post‐operatively were lower than those at 6 months, but this difference was not significant (P= 0.0805) between the two time points in the m‐o‐m group. Cr levels were persistently elevated after surgery and were increased by 10‐fold compared with those at baseline in the m‐o‐m group. Conclusions: Co and Cr levels in scalp hair are ideal indicators for metal levels in the body after HRA. Co and Cr levels in the body were greatly increased after metal‐on‐metal HRA. Long‐term accumulation of these metals needs to be further investigated.     

Hexavalent chromium induced stress and metabolic responses in hybrid willows

Metabolic responses to hexavalent chromium (Cr⁶⁺) stress and the uptake and translocation of Cr⁶⁺ were investigated using pre-rooted hybrid willows (Salix matsudana Koidz × Salix alba L.) exposed to hydroponic solution spiked with K₂CrO₄ at 24.0 ± 1°C for 192 h. Various physiological parameters of the plants were monitored to determine toxicity from Cr⁶⁺ exposure. At Cr⁶⁺ treatments of ≤2.1 mg Cr/l, the transpiration rate of plants was > 50% higher than that of the non-treated control plants. As Cr concentrations were increased further, a slight increase in the transpiration rate was also observed compared with the controls. Negligible difference in the chlorophyll contents in leaves between the treated and the non-treated control plants was measured, except for willows exposed to 1.05 mg Cr/l. The response of soluble proteins in leaves of willows to Cr treatments was remarkable. Cr-induced toxicity appeared in all treatments resulting in reduced activities of catalase (CAT) and peroxidase (POD) compared to the controls. Superoxide dismutases (SOD) activity in the leaf cells showed a positive increase after Cr exposure. Of all selected parameters, soluble proteins in leaves were the most sensitive to Cr⁶⁺ doses, showing a significant linear correlation negatively (R ² = 0.931). Uptake of Cr⁶⁺ by willows grown in flasks was found to increase linearly with the added Cr⁶⁺ (a zero order kinetics), as indicated by the high R ² (0.9322). Recovery of Cr in different parts of plant materials varied significantly with roots being the dominant site of Cr accumulation. Although the translocation to shoots was detected, the amount of Cr translocated to shoots was considerably small. The capacity of willows to assimilate Cr⁶⁺ was also evaluated using detached leaves and roots in sealed glass vessels in vivo. Uptake of Cr by roots was mediated possibly through an active transport mechanism, whereas the cuticle of leaves was the major obstacle to uptake Cr from the hydroponic solution. In addition, both cysteine and ascorbic acid showed a remarkable potential to reduce Cr⁶⁺ at a neutral pH. Results indicated that the added Cr did not cause deleterious effects on plant physiological functions over a 192-h period of exposure. Significant removal of Cr from the hydroponic solution was observed in the presence of hybrid willows. The data also suggest that phytoremediation of Cr⁶⁺ is possible and ecologically safe due to the minor translocation of Cr to aerial tissues.     

Influence of alloying elements on the corrosion stability of CoCrMo implant alloy in Hank's solution

The behavior of a CoCrMo alloy and its components was studied in simulated physiological solution (Hank’s solution) using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The passivation of all samples occurred spontaneously at the open circuit potential. The composition of the oxide films as a function of the solution components and the applied potential is discussed. The electrochemical properties of the spontaneously passivated electrodes at the open circuit potential were studied by EIS. The polarization resistance (R_p) and the electrode capacitance (C_dl) were determined. The higher R_p of the alloy than of the chromium pointed to the stabilizing effect of the other alloy components. The concentration of the metallic ions in a simulated physiological solution, measured by inductively coupled plasma-mass spectrometry, was in accordance with the values of both the R_p determined from EIS data and current densities measured with CV.     

Chromium(III) oxide nanoparticles induced remarkable oxidative stress and apoptosis on culture cells

Chromium(III) oxide (Cr₂O₃) is used for industrial applications such as catalysts and pigments. In the classical form, namely the fine particle, Cr₂O₃ is insoluble and chemically stable. It is classified as a low‐toxicity chromium compound. Recently, industrial application of nanoparticles (a new form composed of small particles with a diameter of ≤100 nm, in at least one dimension) has been increasing. Cellular effects induced by Cr₂O₃ nanoparticles are not known. To shed light upon this, the release of soluble chromium from Cr₂O₃ nano‐ and fine‐particles in culture medium was compared. Fine Cr₂O₃ particles were insoluble in the culture medium; on the contrary, Cr₂O₃ nanoparticles released soluble hexavalent chromium into the culture medium. Cr₂O₃ nanoparticles showed severe cytotoxicity. The effect of Cr₂O₃ nanoparticles on cell viability was higher than that of fine particles. Cr₂O₃ nanoparticles showed cytotoxicity equal to that of hexavalent chromium (K₂Cr₂O₇). Human lung carcinoma A549 cells and human keratinocyte HaCaT cells showed an increase in intracellular reactive oxygen species (ROS) level and activation of antioxidant defense systems on exposure to Cr₂O₃ nanoparticles. Exposure of Cr₂O₃ nanoparticles led to caspase‐3 activation, showing that the decrease in cell viability by exposure to Cr₂O₃ nanoparticles was caused by apoptosis. Cellular responses were stronger in the Cr₂O₃ nanoparticles‐exposed cells than in fine Cr₂O₃‐ and CrCl₃‐exposed cells. Cellular uptake of Cr₂O₃ particles were observed in nano‐ and fine‐particles. The cellular influence of the extracellular soluble trivalent chromium was lower than that of Cr₂O₃ nanoparticles. Cr₂O₃ nanoparticles showed cytotoxicity by hexavalent chromium released at outside and inside of cells. The cellular influences of Cr₂O₃ nanoparticles matched those of hexavalent chromium. In conclusion, Cr₂O₃ nanoparticles have a high cytotoxic potential. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2013.     

微波消解-电感耦合等离子体质谱法测定胶囊中的铬

本文通过对胶囊进行预处理,建立了ICP-MS法测定胶囊中铬含量的检测方法。该方法检出限为0．18μg／L,精密度RSD为0．8％。该方法灵敏、准确、可靠,对控制胶囊中铬元素的含量有实际意义。     

Manganese–Cobalt Based Spinel Coatings Processed by Electrophoretic Deposition Method: The Influence of Sintering on Degradation Issues of Solid Oxide Cell Oxygen Electrodes at 750 °C

This paper seeks to examine how the Mn–Co spinel interconnect coating microstructure can influence Cr contamination in an oxygen electrode of intermediate temperature solid oxide cells, at an operating temperature of 750 °C. A Mn–Co spinel coating is processed on Crofer 22 APU substrates by electrophoretic deposition, and subsequently sintered, following both the one-step and two-step sintering, in order to obtain significantly different densification levels. The electrochemical characterization is performed on anode-supported cells with an LSCF cathode. The cells were aged prior to the electrochemical characterization in contact with the spinel-coated Crofer 22 APU at 750 °C for 250 h. Current–voltage and impedance spectra of the cells were measured after the exposure with the interconnect. Post-mortem analysis of the interconnect and the cell was carried out, in order to assess the Cr retention capability of coatings with different microstructures.     

Magnetron Sputtering vs. Electrodeposition for Hard Chrome Coatings: A Comparison of Environmental and Economic Performances

The coating of materials with specific films is widely used to improve material properties and many technologies exist to perform it. In the last few years, the replacement of wet electrodeposition processes has been continuously encouraged in the EU due to the problematic waste management linked to those processes. In this paper, magnetron sputtering is studied as an alternative to conventional electrodeposition by comparing the technologies’ environmental impacts and costs. From the study, it appears that while magnetron sputtering greatly reduces hexavalent chromium emissions over the production, it has an increased electricity consumption mostly due to its lower production capacity, thus leading to more greenhouse gas emissions. Furthermore, a short discussion on the quantification of the impact of hexavalent chromium emissions is conducted. Regarding costs, the electrodeposition process has a lower cost of investment and of consumables, but requires more work time for the different steps of the process, making the total price per functional unit roughly equal. However, the cost per functional unit strongly depends on assumptions on the required work time, for which a sensitivity study is performed. Finally, the impacts of these two competing coating processes are discussed to complete the technological comparison for the case of hard chromium deposition.     

镍铬合金烤瓷修复体拆除前后患牙龈下菌群的变化

背景：目前有关镍铬合金烤瓷修复体对龈下菌群影响的研究还较少。目的：探讨镍铬合金烤瓷修复体对龈下菌群构成比的影响。方法：选择因怀疑镍铬合金烤瓷修复体影响健康而要求拆除原修复体的烤瓷牙患者9例（患牙12颗）,于镍铬合金烤瓷烤瓷修复体拆除前、拆除后1个月、拆除后3个月时,采用变性梯度凝胶电泳法检测镍铬合金烤瓷修复体基牙及对侧同名天然牙的龈下菌斑。结果与结论：修复体拆除后1,3个月,患牙龈下菌斑的变性梯度凝胶电泳图谱与拆除前相比均发生了明显变化,而且拆后3个月与拆后1个月相比也发生了较明显变化;此外,选择在修复体拆除前龈下菌斑中经常出现而在拆除后消失或减弱的变性梯度凝胶电泳图像中一些特异性条带作16S rDNA片段的序列分析,结果显示这些特异条带的基因序列分别与啮蚀艾肯菌、直形弯曲菌和隐藏优杆菌有着较高的序列相似度。结果表明镍铬合金烤瓷修复体导致了修复基牙龈下菌群组成的变化,并且导致了部分牙周可疑致病菌构成比增加。