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).
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.
Summary. In this randomized, multicenter, controlled, doubleblind, sequential trial, 381 patients undergoing primary total knee replacement were randomly assigned to receive subcutaneous injections of either 3500 IU anti-factor Xa of bemiparin sodium, first dose 6 h after surgery, or 40 mg of enoxaparin, first dose 12 h before surgery, followed by daily doses for 10 AE 2 days, for the prophylaxis of venous thromboembolism. The primary efficacy endpoint was venous thromboembolism up to postoperative day 10 AE 2, defined as deep vein thrombosis detected by mandatory bilateral venography, documented symptomatic deep vein thrombosis and/or documented symptomatic pulmonary embolism. The primary safety endpoint was major bleeding. Eighty-seven percent of all randomized patients (333 of 381 patients) were evaluable for efficacy. The incidence of venous thromboembolism was 32.1% (53 of 165 patients) in the bemiparin group and 36.9% (62 of 168 patients) in the enoxaparin group. The absolute risk difference was 4.8% in favor of bemiparin [95% confidence interval (CI), À15.1% to 5.6%; non-inferiority P-value: 0.02; superiority P-value: 0.36]. The incidence of proximal deep vein thrombosis was 1.8% (three of 165 patients) in the bemiparin group and 4.2% (seven of 168 patients) in the enoxaparin group. Major bleeding occurred in six patients (three in each group). There were no deaths during the study. This trial shows that bemiparin started postoperatively is as effective and safe as enoxaparin started preoperatively in the prevention of venous thromboembolism in patients undergoing total knee replacement.
A study on the level of metals released to body fluids from patients carrying metal-on-metal (based on Co-Cr alloys) total hip prosthesis and titanium alloys dental implants has been conducted. In the first part, total elemental determination of Co, Cr, Ti, Mo and Mn was done in whole blood and urine for both, control individuals and hip arthroplasty patients. Additionally, the work was extended to patients who carried dental implants. The samples, either acid digested (blood) or just diluted (urine) were analyzed using a double focusing inductively coupled plasma mass spectrometer (DF-ICP-MS). Both strategies are validated using the corresponding certified reference materials. The findings revealed an increased concentration of Cr and Ti and, to a lower extent, Co and Mn in the blood and urine of the patients. The second part of the work tries to explore the possible association of the released metals to human serum proteins. For this purpose, speciation of the above mentioned metals is accomplished using liquid chromatography (anion exchange) with ICP-MS detection. Such studies, firstly conducted in incubated standards and then in fresh serum from the patients, showed the elution of Mn associated to transferrin. Co eluted associated to albumin and Cr could not be detected. Spiking experiments showed that Cr(III) is clearly associated to transferrin and supports the theory that Cr is eliminated from the prosthesis as Cr(VI) that shows no interaction with the studied serum proteins.
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.
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