Measurement of Serum Sodium and Magnesium by Inductively Coupled Plasma Mass Spectrometry with Aluminum as Internal Standard

BACKGROUND

Serum sodium and magnesium are important clinical laboratory tests and accurate testing results are needed for the correct interpretation of the tests. Standardization of serum sodium and magnesium measurements requires simple and reliable reference methods.

METHODS

Inductively coupled plasma mass spectrometry (ICP-MS) methods for the measurement of serum sodium and magnesium were developed. Aluminum was used as an internal standard. Serum samples were spiked with the internal standard, digested with 69% nitric acid at 150 degrees C and measured for 23Na/27Al and 24Mg/27Al ratios by ICP-MS. The measurements were calibrated by bracketing calibrators and serum sodium and magnesium concentrations were calculated by comparing the ion ratios of the serum samples with that of the calibrators.

RESULTS

The correlation coefficients between the measured ion ratios and the analyte concentrations were all > 0.9999 for both sodium and magnesium. The coefficients of variation of the measurements were 0.07% - 0.14% for sodium and 0.21% - 0.36% for magnesium. No significant interferences were detected and the analytical recoveries were 100.25% and 100.11% for sodium and magnesium, respectively. The accuracy of the measurements was also verified through measurement of certified reference materials and participation in international interlaboratory comparisons.

CONCLUSIONS

New ICP-MS methods for serum sodium and magnesium have been developed. The methods are specific, precise, simple and low in cost and may be used as candidate reference methods in the standardization of serum sodium and magnesium measurements.

Correlation of cadmium and aluminum in blood samples of kidney disorder patients with drinking water and tobacco smoking: related health risk

The combined exposure to aluminum (Al) and cadmium (Cd) causes more pronounced adverse health effects on humans. The kidneys are the main organs affected by internal exposure to Cd and Al via food and non-food items. The objective of present study was to measure the Al and Cd concentrations in cigarettes tobacco (branded and non-branded) and drinking water (domestic treated, ground and lake water) samples in southern part of Pakistan, to assess the risk due to ingestion of water and inhalation of cigarettes smoke containing high concentrations of both elements. The study population (kidney disorder and healthy) divided into two group based on consuming lake and ground water, while smoking non-branded cigarette as exposed, while drinking domestic treated water and smoking branded cigarette as non-exposed. Electrothermal atomic absorption spectrometry was used to determined Cd and Al concentrations in tobacco, drinking water and blood samples. The resulted data indicated that the levels of Al and Cd in lake and underground water were higher than the permissible limit in drinking water recommended by the World Health Organization. The biochemical parameters of exposed and referent patients, especially urinary N-acetyl-h-glucosaminidase, were used as a biomarkers of kidney disorder. Exposed kidney disorder patients have higher levels of Cd and Al than the exposed referents subjects, while difference was significant when compared to resulted data of non-exposed patients and referents (p = 0.01-0.001). The pearson correlation showed positive correlation between both toxic element concentrations in water, cigarettes versus blood samples of exposed subjects (r = 0.20-0.67 and 0.71-0.82), while lower values were observed for non-exposed subjects (r = 0.123-0.423 and 0.331-0.425), respectively.

Therapy and monitoring of hypersiderosis in chronic renal insufficiency

In RDT hemosiderosis appears to be an inevitable complication only in the small number of patients in need of frequent transfusions. To prevent clinical consequences (e.g. cardiomyopathy) known from polytransfused patients without renal disease, transplantation should be considered in RDT patients in need of frequent transfusions. Iron substitution - preferably oral - to replace dialysis-related iron loss does not cause clinically significant hemosiderosis provided iron stores are monitored adequately. A sufficient method of controlling iron stores in RDT patients under iron substitution or regular transfusion therapy is a twice annual determination of serum ferritin concentration. The treatment of choice for hemosiderosis in nontransfused RDT patients is discontinuation of iron substitution. When polytransfused RDT patients with severe hemosiderosis cannot be transplanted and submitted consecutively to phlebotomy, DFO treatment is indicated. Quantitative data regarding optimal dosage and application of DFO in RDT patients are not yet available. Constant infusion of DFO during hemodialysis may be superior to bolus application.

The binding, transport and fate of aluminium in biological cells

Aluminium is the most abundant metal in the Earth's crust and yet, paradoxically, it has no known biological function. Aluminium is biochemically reactive, it is simply that it is not required for any essential process in extant biota. There is evidence neither of element-specific nor evolutionarily conserved aluminium biochemistry. This means that there are no ligands or chaperones which are specific to its transport, there are no transporters or channels to selectively facilitate its passage across membranes, there are no intracellular storage proteins to aid its cellular homeostasis and there are no pathways which evolved to enable the metabolism and excretion of aluminium. Of course, aluminium is found in every compartment of every cell of every organism, from virus through to Man. Herein we have investigated each of the 'silent' pathways and metabolic events which together constitute a form of aluminium homeostasis in biota, identifying and evaluating as far as is possible what is known and, equally importantly, what is unknown about its uptake, transport, storage and excretion.

Comparative evaluation of essential and toxic elements in the blood of kidney failure patients and healthy referents

The aim of the present study was to evaluate the comparative distribution, correlation, and apportionment of selected elements-aluminum (Al), calcium (Ca), cadmium (Cd), potassium (K), magnesium (Mg), sodium (Na), and lead (Pb)-in the blood samples of male kidney failure patients (KFP) and healthy subjects of age ranged 30-60 years. The blood samples were digested with nitric acid and perchloric acid mixture (2:1), followed by the quantification of elements by atomic absorption spectrometry. The concentration of essential elements in blood samples of KFP were found in the range of Ca (97-125), Mg (18-36), Na (2971-3685), and K (177-270) mg/L while, the levels of Al, Cd, and Pb were found in the range of (475-1275), (0.9-9.9), and (211-623) μg/L, respectively. In the healthy referents, concentration of electrolytes in blood samples was lower than KFP, but difference was not significant (p > 0.05). While the levels of toxic elements in blood samples of referents were three- to sixfold lower than KFP (p < 0.01). Principal component analysis (PCA) and cluster analysis (CA) of the element data manifested diverse apportionment of the selected elements in the blood sample of the KFP compared with the healthy counterparts.

Plasma and mitochondrial membrane perturbation induced by aluminum in human peripheral blood lymphocytes

Aluminum is a redox-inert element that could induce cell damage via activation of oxidative stress. In this work, the effect of aluminum on different cellular compartments of human peripheral blood lymphocytes was studied. The presence of aluminum induced a lipid peroxidation and physico-chemical modifications at the membrane level. A decrease in fluorescence anisotropy of TMA-DPH and in the polarity of the lipid bilayer with a concomitant shift toward a gel phase was observed, while the pyrene excimerization coefficient (Kex) increased. Flow cytometry measurements, using JC-1, Rhodamine 123 and H2-DCFDA as fluorescent probes, indicated that aluminum induces a slight mitochondrial membrane depolarization that was associated with a moderate increase in reactive oxygen species production. A significative influence on these parameters was measured only at high aluminum concentration.

Chronic exposure to aluminum, nickel, thallium and uranium and their relationship with essential elements in human whole blood and blood serum

This study aimed to evaluate the influence of exposure to aluminum, nickel, thallium and uranium on the metabolism of essential elements in humans, as well as the relationship between uranium, thallium, nickel, and aluminum and essential elements (Ca, Mg, Zn, Se, Mn, Co, Cr, and Mo) in the whole blood and blood serum of healthy men who were occupationally exposed. This study included 97 healthy men, 31-64 years age, including 70 workers in a thermo power plant and 27 control subjects. The results showed that chronic, moderate exposure of trace elements (Al, Ni, Tl, and U) lead to decreased serum chromium (SCr) and blood molybdenum levels (BMo), whereas by the results achieved in terms of correlations between non-essential and essential elements, non-essential elements such as uranium, thallium, nickel, and aluminum, despite their concentration within the reference values, are strongly competitive with essential elements in biochemical processes.

Chemometric methods for studying the relationships between trace elements in laryngeal cancer and healthy tissues

A quick and reliable method for the evaluation and classification of two types of tissues is presented. Several chemometric methods were applied to evaluate multivariate data of the tissue samples with respect to the content of trace elements. The content of Pb, Al, Zn, Cd, Cu, Ni and Co was determined in samples of healthy and cancerous tissue obtained from 26 patients. Determination was done at milligram/kilogram level with inductively coupled plasma optical emission spectrometry (ICP-OES) and atomic absorption spectroscopy (AAS) techniques. Contents of trace metals in studied tissues are not normally distributed; however, normal distribution was confirmed for log values. There is a statistically significant difference in the content of Zn, Cd, Cu and Al (p<0.01) and Ni and Co (p<0.05) when healthy tissue is compared to cancerous one. Correlation between contents of trace elements for studied tissues was positive; the highest was found between Zn and Cu. A chemometric methodology seems to be a promising tool for classifications of the tissue samples.

[Experimental evaluation of combined effects caused by stress and metals (cadmium and aluminium) in reproductivity of male rats]

To investigate combined effects of stress and metal (aluminium, cadmium) on reproductivity, male rats twice per week received intraperitoneal injections of aluminium (3.8 mg Al3+ per kg of body weight) or cadmium (0.3 mg Cd2+ per kg of body weight) and were subjected to stress via short-term immobilization during spermatogenic cycle (54 +/- 3 days). Findings are cumulation of both cadmium and aluminium in genitals and brain, increasing under stress. When acting separately to the laboratory animals, the three factors (aluminium/cadmium/stress) increase serum corticosterone level, change testosterone level, increase number of aberrant mitoses of spermatogenic epithelium cells, increased sperm count with fragmented DNA, lower percentage of the impregnated females. If the exposure combined with stress, spermatogenesis disorders are more marked, and preimplantation death rate of intact females' offspirngs becomes statistically significant.

Computer simulation of speciation of trivalent aluminum, gadolinium and yttrium ions in human blood plasma

The speciation of Al3+, Gd3+ and Y3+ ions in human plasma has been studied by computer simulation using the program HySS2009. A literature computer model of blood plasma was updated and comprised 9 metals, 43 ligands and over 6100 complexes. To this model critically evaluated data of Al3+, Gd3+ and Y3+ constants with blood plasma ligands have been added. Low molecular mass (LMM) speciation of Al3+ ion strongly depends upon the chosen equilibrium model of the metal - phosphate and metal - citrate systems. The obtained computer simulation of LMM speciation data of Al3+ ion were: AlPO4Cit (40.7%), AlPO4CitOH (22.9%), AlCitOH (19.2%) and AlPO4(OH) (12.7%) (% of total LMM Al species pool); for Gd3+ ion: GdAspCit (30%) and GdCit(OH)2 (20%) (% of total [Gd]) and for Y3+ ion: YCit (48%), Y(CO3)2 (32%) and Y(CO3) (11%) (% of total [Y]). Citrate appears as the important binding and mobilizing ligand for all examined ions, while the dominating species are the ternary ones.