High-resolution ICP-MS determination of Ti, V, Cr, Co, Ni, and Mo in human blood and urine of patients implanted with a hip or knee prosthesis.

The main components (Ti, V, Cr, Co, Ni, and Mo) of metallic alloys currently used in hip and knee articular prostheses have been simultaneously determined in human whole blood and urine of implanted people by a (HR)-ICP-MS method previously developed in our laboratory. The determination of those elements has been carried out in patients with knee and hip prosthesis and in a group of pre-operation patients without any metallic device in their bodies, used as controls, demonstrating the usefulness of this technique to perform multielement analysis at ppt levels in complex matrices. The concentrations of V, Cr, Co, Ni, and Mo in urine and blood of implanted people turned out to be very similar to those obtained in control patients. However, raised Ti levels could be found both in urine and blood of patients with articular prostheses made or coated with a titanium alloy (Ti(6)Al(4)V).

ICP-MS multielemental determination of metals potentially released from dental implants and articular prostheses in human biological fluids.

A sector field high-resolution (HR)-ICP-MS and an octapole reaction system (ORS)-ICP-MS have been compared for the simultaneous determination of traces of metals (Ti, V, Cr, Co, Ni, and Mo) released from dental implants and articular prostheses in human biological fluids. Optimum sample treatments were evaluated to minimize matrix effects in urine and whole blood. Urine samples were diluted tenfold with ultrapure water, whereas whole blood samples were digested with high-purity nitric acid and hydrogen peroxide and finally diluted tenfold with ultrapure water. In both matrices, internal standardization (Ga and Y) was employed to avoid potential matrix interferences and ICP-MS signal drift. Spectral interferences arising from the plasma gases or the major components of urine and whole blood were identified by (HR)-ICP-MS at 3,000 resolving power. The capabilities of (HR)-ICP-MS and (ORS)-ICP-MS for the removal of such spectral interferences were evaluated and compared. Results indicate that polyatomic interferences, which hamper the determination of such metallic elements in these biological samples, could be overcome by using a resolving power of 3,000. Using (ORS)-ICP-MS, all those elements could be quantified except Ti and V (due to the polyatomic ions 31P16O and 35Cl16O, respectively). The accuracy of the proposed methodologies by (HR)- and (ORS)-ICP-MS was checked against two reference materials. Good agreement between the given values and the concentrations obtained for all the analytes under scrutiny was found except for Ti and V when analyzed by (ORS)-ICP-MS.

Effect of VDR gene polymorphisms on osteocalcin secretion in calcitriol-stimulated human osteoblasts.

BACKGROUND: The impact of vitamin D receptor (VDR) gene polymorphisms in bone metabolism remains controversial. Some authors have found a beneficial effect of some VDR gene polymorphisms, while others found no differences, or even a lower bone mass in subjects with the same type of polymorphisms. The aim of this study was to assess if the VDR gene polymorphisms could have an effect on the calcitriol-stimulated osteocalcin in human osteoblasts. METHODS: Osteoblasts were obtained from human femoral necks replaced because of osteoarthritis. Bones were cut into pieces of 1 to 2 mm and placed in a nylon mesh. After the migration of osteoblasts, the pieces were collected and cultured with different concentrations of calcitriol (10(-8), 10(-9), and 10(-1)0 mol/L). After 48 hours of incubation with calcitriol, the osteocalcin secreted into the medium (corrected by either total proteins or total DNA content) was measured. The DNA was extracted from the osteoblasts, amplified by polymerase chain reaction (PCR), and analyzed for target sequences sites of the BsmI, ApaI, TaqI, and FokI restriction enzymes. RESULTS: The response observed in osteocalcin secretion in the bb or TT genotypes doubled the response observed in the BB or tt genotypes (calcitriol 10(-8) and 10(-9) mol/L). A slight trend was also observed with the aa genotype. Men showed higher levels of osteocalcin secretion than women. Age did not show any influence in osteocalcin secretion. CONCLUSION: VDR alleles and gender demonstrated an effect on the osteocalcin secretion. BB or tt genotypes, and also the "A" allele, showed the lowest calcitriol-stimulated osteocalcin secretion.