Concentrations of seven trace elements in different hematological matrices in patients with type 2 diabetes as compared to healthy controls.

This study aimed to compare the trace element status of patients with type 2 diabetes (n = 53) with those of nondiabetic healthy controls (n = 50). The concentrations of seven trace elements were determined in the whole blood, blood plasma, erythrocytes, and lymphocytes of the study subjects. Vanadium and iron levels in lymphocytes were significantly higher in diabetic patients as compared to controls (p < 0.05 for iron and p < 0.01 for vanadium). In contrast, lower manganese (p < 0.01) and selenium (p < 0.01) concentrations were detected in lymphocytes derived from patients with type 2 diabetes versus healthy subjects. Furthermore, significantly lower chromium levels (p < 0.05) were found in the plasma of diabetic individuals as compared to controls. Trace element concentrations were not dependent on the degree of glucose control as determined by correlation analysis between HBA1c versus metal levels in the four blood fractions. In summary, this study primarily demonstrated that trace element levels in lymphocytes of patients with type 2 diabetes could deviate significantly from controls, whereas, in general, no considerable differences could be found when comparing the other fractions between both patient groups. Therefore, it seems reasonable to analyze metal levels in leukocytes to determine trace element status in patients with type 2 diabetes and perhaps in other diseases.

Determination of Ca, Mg, Fe, Cu, and Zn in blood fractions and whole blood of humans by ICP-OES.

Inductively coupled plasma-optical emission spectrometry (ICP-OES) was applied to the determination of the elements Ca, Mg, Fe, Cu, and Zn in blood plasma, erythrocytes, lymphocytes, and whole blood to obtain reliable data on their distribution in blood fractions. The samples were carefully collected to avoid contamination. Two different nebulizers (Babington and Meinhard) were tested and optimized for this analytical problem. Line selections for all elements of interest were performed (LODs were 0.8 microg/L for Ca, 1.7 microg/L for Cu, 3.0 microg/L for Fe, 1.1 microg/L for Mg, and 4.2 microg/L for Zn). Recoveries were determined as approx. 100%, and standard reference material was analyzed to obtain reliable data on element distribution. The optimized method was applied to the determination of Ca, Mg, Fe, Cu, and Zn in the course of a clinical study on blood and blood fractions of two groups of humans of differing health. The concentrations measured in blood fractions were verified by balancing with the values found in whole blood.

ETAAS method for the determination of Cd, Cr, Cu, Mn and Se in blood fractions and whole blood.

An electrothermal atomic absorption method (ETAAS) for the direct determination of trace elements (Cd, Cr, Cu, Mn, Se) both in blood fractions (erythrocytes, plasma and lymphocytes) and whole blood was developed. Zeeman background correction and graphite tubes with L'vov platforms were used. Samples were diluted with HNO3/Triton X-100 and pipetted directly into the graphite tube. Ashing, pretreatment and atomization steps were optimized carefully for the different fractions and elements applying different matrix modifiers for each element. For the lymphocyte fraction a multi-fold injection technique was applied. Low detection limits of the ETAAS method (Cd 0.13 microgram/L, Cr 0.11 microgram/L, Cu 0.52 microgram/L, Mn 0.13 microgram/L, Se 0.7 microgram/L of whole blood) combined with small quantities of sample necessary for analysis allow determination of trace elements in this matrix. Verification of possible differences in the trace element status of humans was performed with statistical significance (P < 0.05). In addition, a contribution to the determination of normal values of essential elements was achieved. The method was applied for determination of trace elements in human blood and blood fractions of two groups (n = 50) different in health status.

Calcium transport from mineral waters across caco-2 cells.

In the present study the absorption of calcium from 13 different mineral waters has been examined. For this purpose the mineral waters were first digested in vitro by simulating gastric and intestinal digestion. Afterward, the absolute and fractional transport rates of calcium from these digested solutions across human colon adenocarcinoma (Caco-2) cell monolayers grown on bicameral filters were measured. Results showed that the fractional transport rates for calcium lie between 1.65 and 6.72% after 90 min of incubation time. The absolute transport values varied between 90.4 and 624.7 pmol/(min x cm(2)). The transport values [pmol/(min x cm(2))] for calcium from the mineral waters were in general not concentration dependent, showing neither signs of saturation kinetics nor unsaturable uptake mechanisms. In addition, the fractional transport rates from mineral waters with similar calcium concentrations were greatly different in some cases. On the basis of these results, it can be concluded that calcium bioavailability from mineral waters could vary dependent on probably several factors.

Determination of Cu, Fe, Mn, and Zn in blood fractions by SEC-HPLC-ICP-AES coupling.

The binding of Cu, Fe, Mn, and Zn to proteins in blood and in blood fractions was investigated, since their interactions in free radical metabolism in humans is of great interest. An HPLC-ICP-AES technique was developed allowing adequate separation of metalloproteins and of inorganic and organic metal species. For the separation of metalloproteins in erythrocytes and blood plasma a Merck Superformance Fractogel EMD BioSEC 650 (S) column was used. Size exclusion chromatography (SEC)-HPLC was hyphenated to ICP-AES both on-line and off-line for the detection of trace elements in the fractions resulting from HPLC separations. HPLC parameters, pH, temperature, flow rate and salt concentration were optimized for the protein separation and the optimal conditions were applied for the hyphenation to the ICP-AES detector. The separation column was calibrated with five standard proteins. For the element determination by ICP-AES a line selection with respect to the sensitivity was performed. Three different methods were used for the determination of trace elements in blood: direct determinations, on-line and off-line SEC-HPLC-ICP-AES measurements. For the optimizing experiments blood samples of one female subject were used. The direct determination by ICP-AES of the elements was performed in blood and blood fractions of ten different subjects to obtain the average concentration ranges. From the results the identification of the protein Cu/Zn superoxide dismutase in erythrocytes was possible. The LOD were 0.03 microgram mL-1 for Cu, 0.026 microgram mL-1 for Fe, 0.8 ng mL-1 for Mn, and 0.09 microgram mL-1 for Zn in a synthetic blood matrix.