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PubMed2006

Long-term changes in trace elements in patients undergoing chronic hemodialysis.

Although the connection between aluminum intoxication and dialysis dementia was identified in the 1980s, understanding of trace element imbalances in hemodialysis patients is as yet incomplete. Recent application of newer inductively coupled plasma-mass spectrometry (ICP/MS) techniques has resulted in renewed study of this population. We used ICP/MS to evaluate serum concentrations of Cu, Se, Zn, Mn, and Ni in a relatively large population of hemodialysis patients compared with healthy age-matched controls. Comparisons were also done by duration of hemodialysis treatment to see whether length of treatment correlates with severity of imbalance. Patients had significantly lower concentrations of the three elements Se, Zn, and Mn. Patients had significantly higher concentrations of Ni, and there was a positive correlation between duration and severity of imbalance for this one element. There was no difference in Cu concentrations between patients and controls. Our findings confirm relative Ni excess and deficiencies of Se, Zn, and Mn in hemodialysis patients, documenting the value of ICP/MS in research work on trace element imbalances as well as clinical monitoring of individual patients.

Case-Control Studies↗
PubMed2005

Zinc: an essential trace element with potential benefits to soldiers.

Zinc is a trace element known to be an essential nutrient for life. It functions as a cofactor for numerous enzymes, including those involved in DNA and RNA replication and protein synthesis. Soldiers represent a unique population faced with intense metabolic and mental demands, as well as exposure to various immune challenges. Some of these factors may affect their dietary zinc requirements. Although severe zinc deficiency is unlikely to occur, some soldiers may experience less than optimal zinc status because of diminished intake coupled with increased requirements. For those soldiers, supplemental dietary zinc may serve a protective function in numerous disease states affecting modern warfighters. This review highlights the importance of adequate zinc nutriture to soldiers and discusses the potential benefits of supplemental zinc in a number of diseases currently affecting soldiers, including diarrhea, respiratory diseases, malaria, and leishmaniasis.

Dietary Supplements↗
PubMed1987

Radiotracers for the determination of the accuracy of trace element analyses.

Many analytical techniques for the determination of trace elements in environmental samples are plagued by ill-defined systematic errors. Investigations of analytical techniques with radioactively labelled analytes can identify systematic errors, lead to their elimination, and can improve the accuracy of the results. Radiotracers are directly detected with high sensitivity and great rapidity in most cases by gamma-ray counters. Examples of the use of radiotracer techniques for the investigation of the following steps of analytical procedures are presented: presampling events, sampling and sample handling, mineralization of samples, separation and preconcentration, and determination. Most of the examples discussed in the text were taken from the analytical chemistry of mercury, sulfur, lead, sodium, zinc and selenium. Other examples are summarized in tables. The results of these investigations clearly show the superiority of the radiotracer technique over other techniques. A more frequent use of the radiotracer technique in investigations aimed at improving the accuracy of analytical procedures is certainly desirable.

Evaluation Studies as Topic↗
PubMed2005

Zinc: a multipurpose trace element.

Zinc (Zn) is one of the most important trace elements in the body and it is essential as a catalytic, structural and regulatory ion. It is involved in homeostasis, in immune responses, in oxidative stress, in apoptosis and in ageing. Zinc-binding proteins (metallothioneins, MTs), are protective in situations of stress and in situations of exposure to toxic metals, infections and low Zn nutrition. Metallothioneins play a key role in Zn-related cell homeostasis due to their high affinity for Zn, which is in turn relevant against oxidative stress and immune responses, including natural killer (NK) cell activity and ageing, since NK activity and Zn ion bioavailability decrease in ageing. Physiological supplementation of Zn in ageing and in age-related degenerative diseases corrects immune defects, reduces infection relapse and prevents ageing. Zinc is not stored in the body and excess intakes result in reduced absorption and increased excretion. Nevertheless, there are cases of acute and chronic Zn poisoning.

Aging↗
PubMed2000

A SXRF method for determining the relative concentration of trace elements in plasma protein affected by cisplatin.

This article presents an analytical method for the determination of the relative concentrations of trace elements in plasma protein by gel chromatography combined with SXRF (synchrotron radiation X-ray fluorescence). The fraction of plasma protein of male Kunming mice (body weight 24.2 +/- 0.3 g), treated with a cisplatin i.p. injection at a dose of 10 mg/kg, was obtained by the separation of a Sephadex G-50 column (buffered with ammonium acetate, pH 5.7). The SXRF experiments were performed at the Beijing Electron Positron Collider synchrotron radiation facility. The elements (Pt, S, Ca, Fe, Ni, Cu, Zn, Se, Br, and Sr) in the fraction of the plasma proteins (>22 kDa) were assayed using highly sensitive SXRF. The relative concentrations of elements were calculated by a normalization of Compton scattering intensity around 22 keV, after the normalization for the collection time of the X-ray spectrum and the counting of the ion chamber, and subtracting the contribution of the polycarbonate film for the supporting sample. The determination could prove that the element Pt in plasma was bound with macromolecular protein. Cu and S were present in the fraction of the protein in mice treated with cisplatin increase, and their ratios of treated/control were 1.66 +/- 0.06 and 1.78 +/- 0.33, respectively; Zn decreased to a ratio of 0.78 +/- 0.09. Our results are in agreement with others that cisplatin exposure leads to a marked loss of kidney copper and a moderate rise in kidney zinc. However, this article primarily describes one of the analytical methods used; it does not emphasize the results of the effect of cisplatin on trace elements in plasma protein.

Animals↗
PubMed2003

Trace element speciation by ICP-MS in large biomolecules and its potential for proteomics.

Latest studies on the chemical association of trace elements to large biomolecules and their importance on the bioinorganic and clinical fields are examined. The complexity of the speciation of metal-biomolecules associations in various biological fluids is stressed. Analytical strategies to tackle speciation analysis and the-state-of-the-art of the instrumentation employed for this purpose are critically reviewed. Hyphenated techniques based on coupling chromatographic separation techniques with ICP-MS detection are now established as the most realistic and potent analytical tools available for real-life speciation analysis. Therefore, the status and potential of metal and semimetals elemental speciation in large biocompounds using ICP-MS detection is mainly focused here by reviewing reported metallo-complexes separations using size-exclusion (SEC), ion-exchange (IE), reverse phase chromatography (RP) and capillary electrophoresis (CE). Species of interest include coordination complexes of metals with larger proteins (e.g. in serum, breat milk, etc.) and metallothioneins (e.g. in cytosols from animals and plants) as well as selenoproteins (e.g. in nutritional supplements), DNA-cisplatin adducts and metal/semimetal binding to carbohydrates. An effort is made to assess the potential of present trace elements speciation knowledge and techniques for "heteroatom-tagged" (via ICP-MS) proteomics.

Animals↗
PubMed1992

Selenium and other trace elements in bluegills from agricultural return flows in the San Joaquin Valley, California.

The effects of water quality and exposure to trace elements in irrigation return flows on bluegills (Lepomis macrochirus) were studied in the Merced River and Salt Slough, tributaries to the San Joaquin River, California, during 1988. Our study revealed that conductivity, turbidity, pH, total filterable residue, total hardness, and alkalinity were significantly greater in the Salt Slough, which receives tile drainage, then in the Merced River, which does not receive tile drainage. The concentrations of all trace elements, except aluminum and selenium, were below levels that are expected to have significant chronic toxic effects on bluegills. Selenium body burdens in bluegills from the Salt Slough have increased over fourfold since 1973. Age 1 bluegills from the Salt Slough were significantly shorter than age 1 bluegills from the Merced River. No other significant differences were noted in length by age. The mean length of age 1 bluegills from the Merced River has been increasing since 1983. In contrast, the length of age 1 bluegills from the Salt Slough has been decreasing. Fecundity of bluegills was lower in the Salt Slough than in the Merced River. The concurrent rise in selenium body burdens in bluegills from the Salt Slough and the decreasing total length of age 1 bluegills suggest a causal link between the two. In addition, the apparent depressed fecundity may also be related to the increased body burdens of selenium.

Animals↗
PubMed2004

Size distribution of trace elements and polycyclic aromatic hydrocarbons in fly ashes generated in Greek lignite-fired power plants.

The fly ashes arrested by the electrostatic precipitators of four large lignite-fired Greek power stations (total installed capacity 4048 MW) were investigated regarding the distribution of 27 major, minor and trace elements and 13 polycyclic aromatic hydrocarbons (PAHs) in six size ranges from <40 to >105 microm. An inverse relationship of concentration with particle size was observed for trace elements, such as As, Se, Zn, Pb, Cd, as well as for Ca, whereas the distribution of the matrix elements Al, Si, Ti, Fe, Mg was fairly flat up to 105 microm with relative enrichment or depletion in larger particle sizes. A reverse relationship of concentration with particle size was also revealed for all PAHs, particularly the heavier compounds. The percent mass of all elements and PAH species in the suspendable fraction (<63 microm) was between 25 and 30%. In all fly ashes, the PAH mixture was dominated by 4-ring species (48-62%) followed by 3-ring compounds (38-41%), whereas the carcinogenic 5- and 6-ring PAHs were less abundant (2-11%). Fly ash PAH concentrations were found to correlate strongly with the concentrations of certain trace elements either positively (e.g. Ba) or negatively (Mg, Cr, V, U) thus suggesting that some lignite elements might promote or prevent PAH formation during combustion. The suspendable fly ash fraction (<63 microm) was found to contain 6-35% of the total mass of individual elements and 10-57% of the total mass of individual PAH components.

Journal Article↗
PubMed2000

Trace element levels in harp seal (Pagophilus groenlandicus) and hooded seal (Cystophora cristata) from the Greenland Sea. A multivariate approach.

Concentrations of the essential trace elements, iron, copper, zinc and selenium and the non-essential elements arsenic, cadmium, total mercury and lead, were measured in the meat, liver and kidney of two species of seals, harp seal (Pagophilus groenlandicus) and hooded seal (Cystophora cristata) collected in the Greenland Sea. The spread among the individual seals was considerable. However, multivariate statistics simplified the evaluation of the data. The muscle tissue contained lower levels of the elements than kidney and liver. The kidney and liver tissue were also different, in particular with higher levels of iron in the liver and higher levels of cadmium in the kidney. Species differences were clear in both liver and kidney tissue, with higher levels of most of the elements in the hooded seals, while the harp seals had a higher burden of arsenic in the two tissues. Male hooded seals had higher levels of mercury and selenium than the females in all tissues. For harp seal there was a slight difference between the sexes in the muscle tissue, while no difference was observed in the liver and kidney tissues. The juvenile seals generally had lower levels of the elements in their tissues than the adults, although copper and zinc were higher in the muscles and livers of the juveniles as was iron in the muscles. No correlation between age and trace element levels in the tissues of the adult seals was observed.

Age Factors↗
PubMed1996

The effects of fluorides and/or trace elements on the solubilities of enamel and cementum.

The purpose of this study is to determine the effects of fluorides and trace elements applied alone or in combination at different concentrations on the solubilities of enamel and cementum surfaces of the same teeth. The study has been performed on enamel and cementum surfaces of the impacted third molars extracted by surgical operation. Aqueous solutions of sodium fluoride, aluminum potassium phosphate, strontium chloride and titanium tetrachloride at different concentrations were applied to the surfaces. The solubilities of enamel and cementum and the depth of etchings have been calculated by means of the inorganic phosphorus in these etching solutions. According to the results, higher concentrations of fluoride and lower concentrations of strontium and titanium led to a significant reduction into solubilities of enamel and cementum. As certain combined applications of fluorides and trace elements decreased both of the enamel and cementum solubilities, it may be assumed that if such a treatment is beneficial during the adolescence of an individual, it may also be used when he is older.

Adolescent↗
PubMedDate not supplied

Trace element status of PKU children ingesting an elemental diet.

We assessed the trace metal status of 10 children (3.5 to 13.3 yr) with phenylketonuria (PKU) who were successively treated for at least 6 months with a semi-synthetic formula restricted in phenylalanine, then for 6 months with a reformulated formula. The reformulated product contained higher concentrations of magnesium (Mg), potassium (K), phosphorus (P), selenium (Se), and zinc (Zn) and lower concentrations of calcium (Ca), sodium (Na), and unsaturated fats. Diet records, blood samples, and urine specimens were collected from each subject. Mean intakes of Mg, K, and Zn increased significantly when subjects were switched to the reformulated product. The subject's mean intakes of Se (for all age groups) and Zn (children 11 to 14 yr old) were below 67% of recommended intakes while they were ingesting the original formula. The mean trace metal concentrations of urine, blood, and serum did not differ significantly during the two periods. Mean serum Zn, Se, and Cu concentrations of the subjects were less than those reported for normal children. Significant negative correlations were obtained between serum Zn concentrations and the molar ratio of dietary (Ca + P):Zn, and the molar ratio of dietary Fe:Zn. No significant differences in mean urinary Cu and Zn excretion (mg/g creatinine) were observed in subjects after they were changed to the reformulated product. Individuals whose primary source of energy and protein is derived from semi-synthetic elemental diets are especially at risk for multiple trace element deficiencies.

Adolescent↗
PubMed1980

Neural tube malformations and trace elements in water.

A retrospective case-control study was conducted to test the hypothesis that there is an association between the trace element content of domestic tap water and neural tube malformations in infants. Of 11 elements examined a notable difference was found only for zinc, this being lower in the cases than in the controls. This difference, however, was small and when allowance is made for the total number of statistical comparisons it is compatible with chance fluctuation. From the results of this study, together with the inconsistency of the literature as a whole, it is concluded that trace elements in tap water are unlikely to be of relevance to congenital malformations.

Epidemiologic Methods↗
PubMedDate not supplied

Toenail trace element levels as biomarkers: reproducibility over a 6-year period.

We assessed the reproducibility over a 6-year period of 16 trace elements measured in toenails by comparing levels in paired specimens collected in 1982-1983 and 1988 from 127 women in the United States. The Spearman correlation coefficients for the reproducibility of toenail levels of selenium and arsenic (both known to reflect intake of these elements) were 0.48 and 0.54. Correlations for other elements ranged from 0.26 (copper) to 0.58 (zinc). In utilizing biomarkers to assess exposure in epidemiological studies of cancer and other chronic disease, random within-person variability in exposure leads to attenuation of measures of association between exposure and disease. We demonstrate the effect of such variability on odds ratios from a hypothetical case-control study. For a true odds ratio of 3.0 (for a comparison of the highest quintile versus the remaining 4 quintiles of exposure) the odds ratios which would be observed in the presence of the degree of within-person variability demonstrated in this study were 2.15 for toenail arsenic and 1.67 for toenail copper levels. Toenail concentrations of certain trace elements are useful biomarkers of exposure in which a single sample is assumed to represent long-term exposure. However, substantial attenuation in measures of association may occur.

Adult↗
PubMed1994

Trace element concentrations in hair of subjects from two South Pacific Islands, Atafu (Tokelau) and Kitava (Papua New Guinea).

The concentrations of trace elements in hair were measured in 108 healthy subjects (60 males and 48 females, mean age 46-years) resident on Atafu (Tokelau) and in 83 subjects (63 males and 20 females, mean age 26-years) living on Kitava island (Papua New Guinea). On Kitava, a traditional subsistence lifestyle uninfluenced by Western dietary habits is still maintained, but on Atafu the dietary habits have been modified by the inclusion of such imported foods as rice, flour, sugar and canned meat and fish. The concentrations of zinc and magnesium in hair were significantly higher in the Kitava than in the Atafu subjects, whereas those of copper were similar in both groups, and those of selenium, mercury, lead and cadmium were higher in Atafu subjects. The levels of serum copper, magnesium and selenium concentrations in Kitava subjects were not so low as to indicate any trace element deficiency. The higher hair content of mercury, lead and cadmium found among Atafu subjects might be due to consumption of marine foods contaminated with metals, consumption of canned foods, or frequent cigarette smoking, though it is difficult to single out any specific factor.

Adolescent↗
PubMed2002

A Monte Carlo model for studying the microheterogeneity of trace elements in reference materials by means of synchrotron microscopic X-ray fluorescence.

Synchrotron micro-XRF, a trace-level microanalytical method, allows quantitative study of the nature and degree of heterogeneity of inorganic trace constituents in solid materials with a homogeneous matrix. In this work, the standard reference materials NIST SRM 613, Trace Elements in 1 mm Glass Wafers, and NIST SRM 1577a, Trace Elements in Bovine Liver, are examined at the 10100-ng mass level using X-ray beams of 5-150 microm in diameter. A procedure based on a large number of repeated analyses of small absolute amounts of the SRMs allows calculation of the minimal representative mass of the standard. The microheterogeneity of both NIST SRM 613 and NIST SRM 1577a was investigated with the aim of evaluating their suitability as reference materials for trace-level microanalytical techniques. A Monte Carlo simulation model was constructed for both homogeneous and heterogeneous materials to elucidate the dependence of the calculated minimal representative mass on the total analyzed mass in the case of materials that showstrongly heterogeneous features at the microscopic level.

Journal Article↗
PubMed1998

Review of the scientific basis for establishing the essentiality of trace elements.

The recent Expert Consultation of World Health Organization (WHO)/Food and Agricultural Organization (FAO)/International Atomic Energy Agency (IAEA) defined essentiality of a trace element as follows: "An element is considered essential to an organism when reduction of its exposure below a certain limit results consistently in a reduction in a physiologically important function, or when the element is an integral part of an organic structure performing a vital function in the organism." This definition omits a previous postulate that the mechanism of action of an essential trace element should be well defined; it also supersedes another criterion, once suggested for essentiality, a normal, rather than log-normal distribution of an element's tissue concentrations. The Expert Consultation offers no generally applicable criteria for the physiological importance of functions, and that determination is left to expert groups charged with setting national and other nutritional recommendations. The use of the term "physiological" rather than "biochemical" strongly implies that neither changes of an element's concentration nor of a specific enzyme function alone are proof of essentiality. Among physiologically important functions are growth, reproduction, longevity, and all metabolic and hormonal functions that bear a clear, inverse relation to disease risk. Finally, the term "consistent" states the need for independent confirmation of the original data, before an element can be recognized as essential. These definitions will be discussed as background for further discussions of our present knowledge of boron (B).

Animals↗
PubMed1999

Exchange of alkali trace elements in hemodialysis Patients: a comparison with Na(+) and K(+).

BACKGROUND: In the past, nephrologists have been troubled by electrolyte disturbances and consequently focused their attention on the importance of maintaining the concentrations of electrolytes within the normal range. However, information about the potential role of trace elements in chronic renal failure is scarce. METHODS: During hemodialysis sessions, the concentrations of the five alkali metal cations lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs) have been determined in plasma and dialysis fluids of chronic hemodialysis patients by inductively coupled plasma mass spectrometry (Li, Rb, Cs) and by ion-sensitive electrodes (Na, K). Strict quality control schemes were applied to all analytical procedures to ensure accuracy and precision of the results. RESULTS: The plasma concentrations of the elements Li, Cs, Rb, and K distinctly decreased to 29, 50, 69, and 71%, respectively, of their initial values during hemodialysis. Simultaneously, the concentrations of these elements in dialysis fluids at the outlet of the dialyzer increased approximately 13-fold for Rb, 11-fold for Li, 3-fold for Cs, and 2-fold for K as compared with the inlet values. The concentrations of Na in plasma and dialysis fluids were almost identical and did not change during hemodialysis. CONCLUSIONS: Li, Rb, and Cs were depleted in hemodialysis patients, although the plasma concentrations of these trace elements still remained within the reference ranges for healthy adults. Consequently, further studies are needed to elucidate the clinical importance and long-term effects of these trace element imbalances - for example, CNS disturbances associated with diminished concentrations of Rb - in hemodialysis patients.

Adult↗
PubMed1999

Trace elements in soils fertilized with poultry litter.

Poultry litter is used on agricultural land because of its high nutrient content. The litter contains trace elements. With land application of litter, these elements may accumulate in the soil or plants, may be transported as run-off to surface water, or may be leached into groundwater. The objective of this research was to measure the concentrations of trace elements in soils fertilized with poultry litter. Soil was collected from three agricultural farms in Wicomico County, MD. These farms had a long history of poultry litter application. A nitric acid extraction was performed on soil samples collected to a depth of 60 cm. The concentrations of As, Cd, Cu, Mn, Pb, and Zn were determined using atomic absorption spectrophotometry. Arsenic, Cd, Cu, and Mn concentrations were higher in the manured fields than in the control fields. Lead and Zn concentrations did not significantly change with the application of poultry litter.

Agriculture↗