Copper In Human Serum Research Articles

Measurement of Magnesium, Zinc, and Copper in Human Serum by Using Isotope Dilution Inductively Coupled Plasma Mass Spectrometry (ID ICP-MS).

In order to evaluate the reliability of the ID ICP-MS method for the measurement of magnesium, zinc, and copper in human serum, we investigated the traceability, precision, trueness, and uncertainty of the method. This method traces the contents of magnesium, zinc, and copper in human serum to the standard materials NIST SRM3131a, SRM3168a, and SRM3114 respectively, thus completing the traceability to SI unit. The repeatability of this method for measuring magnesium, zinc, and copper in the human serum reference material GBW09152 was found to be 0.2%, 0.7%, and 0.6% (n = 9), respectively. The measurement, when employed to measure the magnesium, zinc, and copper in standard materials, had caused a maximum deviation of less than 0.88%, 1.35%, and 1.15%, respectively. The measurement results are within the stated uncertainty range of standard materials. The expanded uncertainties were 0.2 mg·kg-1, 0.04 mg·kg-1, and 0.08 mg·kg-1 (K = 2) for magnesium, zinc, and copper, respectively. Therefore, this method has high trueness, good reproducibility, and simple operation and is suitable for tracing the values of magnesium, zinc, and copper in human serum.

Speciation of copper in human serum using conjoint liquid chromatography on short-bed monolithic disks with UV and post column ID-ICP-MS detection

A new method based on conjoint liquid chromatography with post-column ID-ICP-MS detection was developed for the speciation of Cu in human serum. Cu ceruloplasmin (Cu-Cp) is suggested as a potential biomarker in cancer diagnosis.

Quantitative correction of matrix effects in the determination of copper in human serum by isotope dilution quadrupole ICP-MS

Quantitative correction of matrix effects in the determination of Cu in human serum by using isotope dilution Q-ICP-MS.

Ultrasensitive Determination of Copper in Complex Biological Media Based on Modulation of Plasmonic Properties of Gold Nanorods

Accurate determination of copper in complex biological media such as cells is quite difficult, and an analytical strategy based on copper-modulated formation of core-shell gold nanorods is described. Selective and label-free sensing can be achieved by measuring the change in the localized surface plasmon resonance absorption. The technique can determine trace amounts of copper in human serum, urine, and red blood cells without or with minimal sample pretreatment. The Cu detection limits are 20.67 μM in human serum, 0.193 μM in human urine, and 3.09 × 10(-16) g in a single cell. The advantages of the technique are the high selectivity, simple or no sample pretreatment, and label free. Boasting a practical detection limit down to 2 fM, only 10(3) red blood cells are needed to conduct the analysis and the technique may be extended to the detection of trace amounts of copper in a single cell.

Separation of metalloproteins using a novel metal ion contaminant sweeping technique and detection of protein-bound copper by a metal ion probe in polyacrylamide gel electrophoresis: distribution of copper in human serum

A polyacrylamide gel electrophoresis (PAGE)-based method has been developed, consisting of two types of gel electrophoresis, to obtain an accurate distribution of protein-bound metal ions in biological samples. First, proteins are separated by PAGE without the uptake of contaminant metal ions in the separation field and dissociation of metal ions from the proteins. This is followed by another PAGE for the separation and detection of protein-bound metal ions in small volume samples with high sensitivity in the ppt range using a fluorescent metal probe. The former is a new technique using blue-native (BN) PAGE to electrophoretically sweep all metal contaminants by employing two kinds of chelating agents. These agents form complexes with contaminants in the gel and the separation buffer solution, which migrate towards opposite pole directions, thus lowering the contaminants to below the ppt level during separation. This is termed "Metal Ion Contaminant Sweeping BN-PAGE (MICS-BN-PAGE)". After the separation of proteins under these first metal-free conditions, the metal ions in the gel fractions are eluted, followed by derivatization of copper ions into the metal probe complexes to be separated and determined by fluorescence detection in the second PAGE. In this PAGE-based method, the copper ions bound to ceruloplasmin and superoxide dismutase were quantitatively determined, in addition to the exchangeable albumin-bound copper ions. This system successfully provided distribution maps of protein-copper in human serum. The precise distribution of copper in human serum was investigated, and found to be different from that which is widely accepted.

Aceruloplasminemia

Ceruloplasmin contains 95% of the copper in human serum and plays an important role in iron efflux from mammalian cells, including brain cells, due to the activity of ferroxidase, which oxidizes ferrous iron following its transfer to the cell surface via the iron transporter, ferroportin, and delivers ferric iron to extracellular transferrin. In the central nervous system, a glycosylphosphatidylinositol (GPI)-anchored ceruloplasmin bound to the cell membranes of astrocytes was found to be the major isoform of this protein. Inherited loss of the protein causes aceruloplasminemia, which is an autosomal recessive disorder characterized by progressive neurodegeneration of the retina and basal ganglia associated with specific inherited mutations in the ceruloplasmin gene. Aceruloplasminemia is classified as an inherited neurodegenerative disorder called "neurodegeneration with brain iron accumulation" (NBIA) due to genetic defects associated with iron metabolism. Clinical and pathologic studies in patients with aceruloplasminemia and ceruloplasmin knockout mice revealed increased lipid peroxidation due to iron-mediated cellular radical injury which is caused by a marked accumulation of iron in the affected parenchymal tissues such as the retina, liver, pancreas and brain. In the following review of aceruloplasminemia, the ceruloplasmin gene expression, structure and function will be presented, and the role of ceruloplasmin in iron metabolism will be discussed. The pathogenesis of aceruloplasminemia provides valuable insights into the mechanisms regulating iron homeostasis and also identified models that can be used to further dissect the role of this metal in neurodegenerative diseases such as Alzheimer's and Parkinson's diseases, in which iron is accumulated.

Employment of Ruthenium as Permanent Modifier for the Determination of Copper in Serum Samples by Electrothermal Atomic Absorption Spectrometry

In the present study, the determination of copper in human serum by electrothermal atomic absorption spectrometry was investigated with susceptible substances to act as chemical modifiers. The optimization of the method involved studies of pyrolysis and atomization temperature curves in the diluted human serum. Ruthenium was the best modifier. With this modifier, recoveries of spiked serum samples on different days ranged from 92% to 105% with a relative standard deviation (RSD) lower than 10% and a tube lifetime higher than 2000 cycles.

Speciation Analysis of Serum Copper by Ultrafiltration Combined with Graphite Furnace Atomic Absorption Spectrometry

AbstractUltrafiltration combined with graphite furnace atomic absorption spectrometry (GFAAS) was used to study protein binding and speciation of copper in human serum. Ultrafiltration was carried out using a cell unit with ultrafiltration membranes having a nominal cut‐off of 10,000 Dalton. The effects of various experimental factors including the kind and concentration of electrolyte, sample storage, pH. pressure and the preconditioning of the membranes on the speciation analysis of serum copper by ultrafiltration were examined. It was observed that 4.5 ± 2.3% of the total copper in serum was ultrafiltrable and this value did not seem to be influenced by the total serum elemental concentration, the pH (6.5–10) and the pressure (≤ 1.5 kg/cm2). The preconditioning of the ultrafiltration system with 0.1 mol/L calcium nitrate can overcome the adsorption loss of copper effectively, and the addition of tris‐HCl solution (pH 7.4) to serum accelerates the ultrafiltration. The present method was proved to be suitable for speciation analysis for its simplicity, rapidity, small sample requirement and easy control. The results obtained with the method are accurate and reliable.

Chemiluminescence flow-through sensor for copper based on an anodic stripping voltammetric flow cell and an ion-exchange column with immobilized reagents.

A novel chemiluminescence (CL) flow-through sensor based on immobilizing all the ingredients involved in the analytical reaction for the determination of copper is proposed. The analytical reagents including luminol and cyanide were coimmobilized permanently on an anion-exchange column, while the analyte copper was retained temporarily by electrochemical preconcentration on a gold electrode placed in an anodic stripping voltammetric flow cell. By injection of a volume of sodium hydroxide through the column with immobilized reagents, luminol and cyanide were eluted from the resins in alkaline aqueous solution and then reacted with copper stripped from the gold electrode to produce a CL signal, by means of which copper could be sensed. The sensor was not susceptible to interference by other metal ions associated with the CL reaction. The response to the concentration of copper was linear in the range of 0.01-10 micrograms/L and an extremely low detection limit of 8.0 x 10(-3) micrograms/L was achieved. A complete analysis could be performed in 4 min with a relative standard deviation of less than 8%. The column with immobilized reagents was readily prepared and could be reused over 200 times. The sensor was applied successfully to the determination of copper in human serum and natural water samples.

Oxidations of vincristine catalyzed by peroxidase and ceruloplasmin.

The dimeric Catharanthus alkaloid vincristine (1) is oxidized to the same ring fission product in incubations with either horseradish peroxidase or the human serum copper oxidase ceruloplasmin. Horseradish peroxidase-catalyzed oxidation of vincristine requires hydrogen peroxide, whereas ceruloplasmin-catalyzed oxidation of vincristine requires chlorpromazine as a "shuttle oxidant". Preparative-scale incubations allowed for the production, isolation, structural characterization, and biological evaluation of the metabolite. The metabolite was identified as the heterocyclic ring cleavage product N-formylcatharinine (5). N-Formylcatharinine was 118 times less active than vincristine in an in vitro test against a human T-cell leukemic cell line. Therefore, these enzyme-catalyzed reactions lead to bioinactivation of vincristine.

Rapid Zeeman atomic absorption determination of copper in serum and urine

In this simple, quick procedure for determining copper in human serum and urine, the serum and urine specimens were analyzed directly after dilution with a solution of HNO3 and Triton X-100, 1 mL/L each. We calibrated with aqueous standards for quantitation in Zeeman background atomic absorption spectrometry. By modifying the drying and pyrolysis stages of the graphite furnace atomic absorption spectrometer, we reduced the analytical time to 30 s per determination. The within-run imprecision (CV) is 2.6% and 3.4% and the between-run imprecision is 0.9% and 2.5% for serum and urine copper at concentrations of 30.4 and 2.70 mumol/L, respectively. The accuracy of this fast method was verified by analyzing the National Institute of Standards and Technology Standard Reference Materials SRM 1598 bovine serum and SRM 2670 urine (agreement with certified values within 0.1 mumol/L for serum and within 0.02 mumol/L for urine), by analytical recovery studies (98% recovered in serum, 100% recovered in urine), and by comparison with our normal routine method. We also used the Quebec Interlaboratory Comparison Program to validate the analytical performance. From the precision and accuracy studies, we conclude that this fast-furnace program is a rapid, simple, and reliable method for determining copper in serum and urine.

In vitro metabolic transformations of vinblastine: oxidations catalyzed by human ceruloplasmin.

The dimeric Vinca alkaloid vinblastine (VLB) undergoes metabolic transformation to three products in a reaction catalyzed by the human serum copper oxidase ceruloplasmin. The enzyme reaction requires chlorpromazine as a shuttle oxidant, and the course of the oxidation reaction appears to be subject to the nature of the shuttle oxidant used. Preparative-scale incubations have resulted in the isolation of three products, which were characterized by chemical and spectral analyses. The metabolites were identified as the ring fission product catharinine, obtained by oxidation of the Iboga ring system; an enamine/ether derivative obtained by oxidation of the Aspidosperma portion of VLB; and a metabolite embodying the same structural changes in both parts of the vinblastine dimeric structure. Catharinine is identical with the product of VLB oxidation obtained by peroxidase oxidation. The other two products are new metabolites and are derivatives of VLB. All of the metabolites are less active than VLB when tested in vitro vs the human T-cell leukemic cell line (CRFF-CEM).

Non-Caeruloplasmin Copper and Ferroxidase Activity in Mammalian Serum. Ferroxidase Activity and Phenanthroline-Detectable Copper in Human Serum in Wilson's Disease

It is thought that 5-10% of human serum copper consists of copper ions complexed with histidine, amino acids or albumin. The phenanthroline assay developed by Gutteridge (Biochem. J. 218, 983-985; 1984) is shown to measure all these forms of copper down to a sensitivity of 0.1 mumol/dm3, yet it does not detect any copper ions in freshly-prepared serum or plasma from rats, mice, rabbits or guinea-pigs, or freshly-prepared serum from humans. It is concluded that the "non-caeruloplasmin copper pool" is much smaller than has previously been supposed. No phenanthroline-detectable copper could be measured in serum freshly prepared from four patients with uncomplicated Wilson's disease, but it could be measured in serum from a patient with fulminant hepatic failure. After liver transplantation, concentrations of phenanthroline-detectable copper in this patient fell to zero within two days. Studies on the ferroxidase activity of freshly-prepared serum or plasma samples shows that little ferroxidase II activity is present in samples from healthy adults or from the patient with Wilson's disease and fulminant hepatic failure. In all the patients, ferroxidase I activities are sub-normal. Freshly-prepared plasma or serum samples from several animal species generally show lower ferroxidase I and greater ferroxidase II activities than do human samples, but only in rabbits does ferroxidase II account for a high proportion of total plasma ferroxidase activity. Storage of biological fluids can cause release of copper from caeruloplasmin and a rise in ferroxidase II activity; these events may have confused some earlier studies.

Differences in human serum copper and zinc levels in healthy and patient populations

This report is designed to re-examine the use of our presently accepted normal laboratory levels for human serum zinc and copper and to suggest a technique, previously unreported in the literature, to more precisely understand the relationship of serum zinc and copper in health and disease. Data from a patient population of 95 and a healthy population of 115 who met certatin criteria are compared.

The identification of metal-protein complexes by gel chromatography and neutron activation analysis

A method for the identification of protein-metal complexes in biological fluids by a combination of gel chromatography and neutron activation analysis is proposed. The distribution of protein-bound copper in human serum is studied as an example of the method.

The state of copper in human serum: evidence for an amino acid-bound fraction.

In addition to copper bound to ceruloplasmin and to albumin, there is a third small fraction of copper in human serum that is bound to amino acids. The amino acid-bound fraction of copper is in equilibrium with albumin-bound copper, and both fractions are probably in equilibrium with ionic copper. Of the 23 amino acids that are known to be in human serum, a substantial number were shown (in physiological concentrations) to compete effectively with albumin for the binding of copper. In this respect, histidine had the most marked effect followed by glutamine, threonine, cystine, and others. The effect of the combined presence of 23 amino acids on the state of copper in human serum could not be explained on the basis of their individual abilities to compete with albumin for the binding of copper. It is suggested that copper may also be present in serum in the form of mixed amino acid-copper complexes consisting of one atom of copper and two different amino acids. Under normal conditions, histidine is the amino acid primarily involved in the formation of mixed amino acid-copper complexes in serum. In combination with histidine and copper, threonine, glutamine, and asparagine are the other amino acids that are most likely to be the third members of these mixed complexes. The first binding site for copper on human albumin is different from subsequent ones in that its binding affinity to copper is much higher. We propose that the amino acid-bound fraction of copper in serum may have a physiological role in the biological transport of copper.

Rubeanic Acid for Determination of Copper in Human Serum

Rubeanic Acid for Determination of Copper in Human Serum