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Background: Little is known about trace metal alterations in the bones of dialysis patients or whether particular types of renal osteodystrophy are associated with either increased or decreased skeletal concentrations of trace elements. Because these patients are at risk for alterations of trace elements as well as for morbidity from skeletal disorders, we measured trace elements in bone of patients with end-stage renal disease. Methods: We analyzed bone biopsies of 100 end-stage renal failure patients enrolled in a hemodialysis program. The trace metal contents of bone biopsies with histological features of either osteomalacia, adynamic bone disease, mixed lesion, normal histology, or hyperparathyroidism were compared with each other and with the trace metal contents of bone of subjects with normal renal function. Trace metals were measured by atomic absorption spectrometry. Results: The concentrations of aluminum, chromium, and cadmium were increased in bone of end-stage renal failure patients. Comparing the trace metal/calcium ratio, significantly higher values were found for the bone chromium/calcium, aluminum/calcium, zinc/calcium, magnesium/calcium, and strontium/calcium ratios. Among types of renal osteodystrophy, increased bone aluminum, lead, and strontium concentrations and strontium/calcium and aluminum/calcium ratios were found in dialysis patients with osteomalacia vs the other types of renal osteodystrophy considered as one group. Moreover, the concentrations of several trace elements in bone were significantly correlated with each other. Bone aluminum was correlated with the time on dialysis, whereas bone iron, aluminum, magnesium, and strontium tended to be associated with patient age. Bone trace metal concentrations did not depend on vitamin D intake nor on the patients’ gender. Conclusions: The concentration of several trace elements in bone of end-stage renal failure patients is disturbed, and some of the trace metals under study might share pathways of absorption, distribution, and accumulation. The clinical significance of the increased/decreased concentrations of several trace elements other than aluminum in bone of dialysis patients deserves further investigation.

To study the possible accumulation of Sr in chronic renal failure patients, methods were developed for the determination of the element in serum, urine, bone, and soft tissues by using Zeeman atomic absorption spectrometry. Serum samples were diluted 1:4 with a Triton X-100–HNO3 mixture, whereas urine samples were diluted 1:20 with HNO3. Bone samples were digested with concentrated HNO3 in stoppered polytetrafluoroethylene (Teflon®) tubes, whereas soft tissues were dissolved in a tetramethylammonium hydroxide solution in water. For serum and urine we used matrix-matched calibration curves, whereas bone and tissue samples were measured against aqueous calibrators. Atomization was performed from the wall of pyrolytically coated graphite tubes for all of the matrices under study. Both inter- and intraassay CVs were

We developed a precise and accurate graphite furnace atomic absorption spectrometric method for the direct determination of zinc in serum. Serum samples are analyzed after 20-fold dilution with water of ultrapure analytical grade. No other reagent is used, from the moment of sampling until measurement. During atomization, the argon flow is kept at 150 mL/min instead of gas stop, to decrease the sensitivity and thus allow lower dilution ratios. Zinc concentrations are determined against a serum-matched calibration curve. Graphite tubes are uncoated and no L'vov platform is used. Between-run CVs were 5.9%, 3.5%, and 1.9% for serum zinc concentrations of 0.93, 1.15, and 1.43 mg/L, respectively. The characteristic mass was 9 pg, and the detection limit (meanblank + 3SDblank) was 0.060 mg/L.

Direct measurement of lead and cadmium in blood and urine by electrothermal atomic absorption spectrometry with deuterium background correction (D2-AAS) is prone to severe matrix and spectral interferences. We overcame these effects by coating the L'vov platform with ammonium molybdate, reducing the atomization time, introducing a post-atomization cooling step, carefully selecting ashing and atomization temperatures, and using an appropriate procedure for matrix modification. To determine Pb and Cd in blood and urine, we used matrix-matched calibration curves. With the proposed procedure for sample preparation, both Pb and Cd in whole blood can be determined in the same diluted sample. Results obtained by D2-AAS correlate closely with those by Zeeman-corrected AAS. Detection limits (mean blank + 3 SDblank) for Pb in urine and blood were 4 micrograms/L. For cadmium, the detection limits were 0.4 and 0.1 micrograms/L for urine and blood analysis, respectively. Between-run CVs were less than 5.0%.

We describe a direct-calibration method for determining aluminum in bone and soft tissues by graphite furnace atomic absorption spectrometry. Aluminum in bone was determined in uncoated tubes, whereas the analytical performance in soft tissue analysis was markedly improved by using pyrolytically coated tubes with a L'vov platform and added calcium. The analytical imprecision (CV) was less than or equal to 5.4% for aluminium concentrations between 12 and 98 micrograms/L, and analytical recoveries of added analyte varied between 94.5% and 103.0%. Detection limits (2 SD of determinations of the zero standard) were 7 and 6 pg for bone and soft tissues, respectively. Characteristic masses (amounts of Al yielding an absorbance signal of 0.0044 A) were 9 and 8 pg, respectively.

Using laser microprobe mass analysis, we studied the ultrastructural localization of aluminum in liver and bone tissue of chronic-hemodialysis patients with proven aluminum-induced osteomalacia. In the liver, aluminum was observed to be almost exclusively associated with iron. Detectable aluminum and large amounts of iron were found in lysosomes of both hepatocytes and Kupffer cells. In bone, aluminum was localized at the osteoid/calcified-bone interface and also was associated with iron in some cases.

We describe different methods of electrothermal atomic absorption spectrometry with automatic sampling for determining aluminum in human serum, blood, urine, and tissues. Contamination with Al originating from receptacles and reagents was minimized. Whole-blood Al concentrations were measured after hemolysis of EDTA-anticoagulated blood samples with Triton X-100. A straightforward method for tissue destruction was developed. Instrument settings of the graphite furnace and of the atomic absorption spectrometer were adjusted so as to obtain close agreement between direct and standard-additions methodologies. The result is a reliable direct method appropriate for use with multiple samples. Tissue Al measurements showed low detection limits and approximately 100% analytical recoveries. Al concentration in serum of 10 healthy volunteers and of 100 chronic hemodialysis patients were 2.0 (SD 0.4) and 77 (SD 70) micrograms/L, respectively. Blood Al concentrations of 10 controls and of 100 dialysis patients were 12.1 (SD 1.5) and 79 (SD 70) micrograms/L, respectively. Al concentrations in serum and blood of 47 chronic hemodialysis patients were not significantly different. Bone Al concentrations were 8.2 (SD 5.8) micrograms/g of fresh tissue for 10 chronic hemodialysis patients without osteomalacia, as compared with 51 (SD 20) micrograms/g for 10 chronic-dialysis patients with Al-induced osteomalacia.

This indirect method for determination of desferrioxamine (DFO, deferoxamine, Desferal) and its chelated compounds ferrioxamine (FO) and aluminoxamine (AIO) in biological fluids involves metal chelate formation and solvent extraction, the metal being determined by Zeeman atomic absorption spectrometry (Zeeman-AAS). Special attention was paid to the pH and recovery of extraction, iron-aluminum interactions, extraction times and volumes, centrifugation rates, and instrument settings. Precautions were taken to avoid contamination with aluminum and iron and to prevent co-extraction of iron and aluminum not chelated to DFO. The addition calibration technique was used for standardization. Mean +/- SD recoveries of AIO and FO after extraction were respectively 98.3% +/- 3.7% and 101% +/- 3.7%. Sensitivity was 45 pg/0.0044 A.s for aluminum and 10 pg/0.0044 A.s for iron. Detection limits were 0.22 mumol/L for AIO, 0.06 mumol/L for DFO and FO.