Determination of lanthanum and rare earth elements in bovine whole blood reference material by ICP-MS after coprecipitation preconcentration with heme-iron as coprecipitant

Preparation and Characterization of Lanthanum-Incorporated Hydroxyapatite Coatings on Titanium Substrates

Titanium (Ti) has been widely used in clinical applications for its excellent biocompatibility and mechanical properties. However, the bioinertness of the surface of Ti has motivated researchers to improve the physicochemical and biological properties of the implants through various surface modifications, such as coatings. For this purpose, we prepared a novel bioactive material, a lanthanum-incorporated hydroxyapatite (La-HA) coating, using a dip-coating technique with a La-HA sol along with post-heat treatment. The XRD, FTIR and EDX results presented in this paper confirmed that lanthanum was successfully incorporated into the structure of HA. The La-HA coating was composed of rod-like particles which densely compacted together without microcracks. The results of the interfacial shear strength test indicated that the incorporation of lanthanum increased the bonding strength of the HA coating. The mass loss ratios under acidic conditions (pH=5.5) suggested that the La-HA coatings have better acid resistance. The cytocompatibility of the La-HA coating was also revealed by the relative activity of alkaline phosphatase, cellular morphology and cell proliferation assay in vitro. The present study suggested that La-HA coated on Ti has promising potential for applications in the development of a new type of bioactive coating for metal implants.

Relationship between lanthanide contents in aquatic turtles and environmental exposures

Trace elements released in the environment during agricultural practices can be incorporated and accumulated in biological fluids and tissues of living organisms. The assessment of these exposures were carried out investigating lanthanide distributions in blood and exoskeleton samples collected from Emys trinacris turtle specimens coming from sites with anthropogenic discharge in western and south Sicily, along migration paths of many bird species from Africa to Europe. The data show a significant (Rxy=0.72; Rxy>0.67; α=0.025) linear relationship between the size of turtle specimens and the lanthanide contents in blood lower than 0.4 μg L(-1) whereas this relationship disappears in blood with higher lanthanide contents. Comparative evaluations of normalised concentrations show that lanthanides fractionate between blood and exoskeleton inducing antithetical lanthanide patterns therein. These features are more evident in specimens with high lanthanide contents in blood, suggesting that lanthanide accumulations in the exoskeleton can represent the physiological response of E. trinacris to environmental and the further confirmation of relationship occurring between the environmental and the biological fluids.

Measurement of serum lanthanum in patients treated with lanthanum carbonate by inductively coupled plasma-mass spectrometry

Background

Lanthanum carbonate is used as a phosphate binder in patients with stage V chronic kidney disease (CKD). While well tolerated in clinical trials, with no toxicity reported as regards bone and liver metabolism, and cognitive function, concerns remain over possible toxicity. Published methods for the measurement of lanthanum ion in biological samples include aggressive and complicated sample preparation steps that are unsuitable for routine use. A simple method has been developed and validated for the measurement of serum lanthanum.

Method

A ThermoFisher Scientific XSERIES-II inductively coupled plasma-mass spectrometer was used to monitor 139La. Validation was undertaken using internal quality control solutions containing lanthanum ion (0.20, 0.70 and 4.00 μg/L). Lanthanum was measured in patients (number = 20) with CKD prescribed lanthanum carbonate (500–1500 mg/d) and patients undergoing haemodialysis not prescribed lanthanum carbonate (number = 20).

Results

Accuracy and imprecision were >95% and <5%, respectively. Calibration was linear (range 0.1–5 μg/L, R2 = 0.99). The lower limit of quantification (LLoQ) was 0.1 μg/L lanthanum ion. In patients with CKD not prescribed lanthanum carbonate, serum lanthanum was below the LLoQ. Out of 20 CKD patients prescribed lanthanum carbonate, serum lanthanum was measurable in only 12 (range 0.11–0.60 μg/L lanthanum ion). There was no apparent relationship between dose and serum lanthanum in these patients.

Conclusions

A lack of relationship between the dose of lanthanum carbonate and the serum lanthanum concentration may have been due to poor adherence to the treatment regimen. However the concentrations measured were close to the LLoQ.

Characterization, physicochemical properties and biocompatibility of La-incorporated apatites

In this study, the physicochemical properties and biocompatibilities of La-containing apatites were intensively investigated together with their characterizations in terms of composition, structure, valent state and morphology using X-ray diffraction, Fourier-transform infrared spectra, X-ray photoelectron spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy, respectively. The results indicate that the La(3+) ion can be incorporated into the crystal lattice of hydroxyapatite resulting in the production of La-incorporated apatites (La(x)Ca(10-x)(PO(4))(6)(OH)(2+x-2y)O(y square y-x) (x> or =0.5, y<1+x/2) or La(x)Ca(10-x)(PO(4))(6)O(y square y-x) (0.5<x<2, y=1+x/2)) by high-temperature solid phase synthesis. For La content <20%, the product is composed of the major phase, La(x)-OAP, as well as a small amount of tricalcium phosphate, but for a La content of 20%, the product is pure La-incorporated oxyapatite with the formula La(2)Ca(8)(PO(4))(6)O(2) (La(2)-OAP, x=2, y=2). It is also found that the La content plays important roles in both the physicochemical properties and biocompatibilities of the La-incorporated apatites. In contrast to La-free apatite, La-incorporated apatites possess a series of attractive properties, including higher thermal stability, higher flexural strength, lower dissolution rate, larger alkaline phosphatase activity, preferable osteoblast morphology and comparable cytotoxicity. In particular, the sintered La-incorporated apatite block achieves a maximal flexure strength of 66.69+/-0.98 MPa at 5% La content (confidence coefficient 0.95), increased 320% in comparison with the La-free apatite. The present study suggests that the La-incorporated apatite possesses application potential in developing a new type of bioactive coating material for metal implants and also as a promising La carrier for further exploring the beneficial functions of La in the human body.

Determination of Manganese in Urine and Whole Blood Samples by Electrothermal Atomic Absorption Spectrometry: Comparison of Chemical Modifiers

In this work, methodologies to determine manganese (Mn) in urine and whole blood by electrothermal atomic absorption spectrometry were developed. The use of Ru, Rh, and Zr as permanent modifiers, Pd as a modifier in solution, and the condition without modifier were investigated for the direct determination of Mn in urine and whole blood samples. The best results for Mn in urine and in whole blood were obtained without modifier use. The analytical characteristic, such as accuracy, precision and limit of detection of the proposed methodology were adequate.

Regional distribution of manganese, iron, copper, and zinc in the rat brain during development

Manganese (Mn), iron (Fe), copper (Cu), and zinc (Zn) concentrations were determined in the brain regions of normal 1-, 3-, 5-, 7-, 14-, 21-, 42-, 77-, and 147-day-old Wistar rats using inductively coupled plasma mass spectrometry (ICP-MS), and their maps were illustrated in color to visually compare the distribution of the elements at various stages of the growth process. Sagittal slices (1-mm thickness) sectioned at the level of the substantia nigra were divided into 18 regions, and the small slice samples were digested in microwave-assisted closed vessels for ICP-MS measurement. Mn, Fe, Cu, and Zn concentrations increased region-specifically with age, and their distributional maps showed some characteristics. These findings are discussed in terms of needs for these trace elements in the normal brain. Among new findings about their brain distribution, it is especially noteworthy that higher concentrations of Mn, Fe, and Zn were observed in the substantia nigra compared with those in neighboring regions. The mapping method in this work is expected to open up possibilities for screening of the in vivo element-element interrelationships among these essential elements.