Serum metal concentrations

Among potentiometric enzyme sensors, the urea enzyme electrode is the oldest (and the most important). The original version consisted of an enzyme layer immobilized in a polyacrylamide hydrophilic gel and fixed in a nylon netting attached to a Beckman 39137 glass electrode, sensitive to the alkali metal and NHj ions [19, 2A Because of the poor selectivity of this glass electrode, later versions contained a nonactin electrode [20,22] (cf. p. 187) and especially an ammonia gas probe [25] (cf. p. 72). This type of urea electrode is suitable for the determination of urea in blood and serum, at concentrations from 5 to 0.05 mM. Figure 8.2 shows the dependence of the electrode response... 

Biomonitoring of environmental and occupationally relevant trace and ultratrace metals (Al, Co, Cr, Cu, Fe, Mn, Ni, Pt, V and Zn) in human serum and urine was carried out using ICP-SFMS at different mass resolutions by Begerow et cd 41 Whereas the elements free from isobaric interferences (Cd, Mn, Pb, Pt and Tl) were measured at low mass resolution (ml Am = 300), the determination of Al, Co, Cr, Cu, Fe, Ni, V and Zn was performed in the medium mass resolution mode (m/Am = 3000).41 Trace metal concentrations (Al, Ba, Be, Bi, Cd, Co, Cr, Hg, Li, Mn, Mo, Ni, Pb, Sb, Sn, Sr, Tl, V, W and Zr) in serum and blood samples from patients with Alzheimer s disease and healthy individuals measured by ICP-SFMS were compared by et al42 An increment of Hg and Sn in serum, higher levels of Co, Li, Mn and Sn and lower levels of Mo in blood were found in Alzheimer s disease samples.42... 

Essential and Nonessential Metals. It is well known that elements in the biological systems may vary a great deal in their concentration from organ to organ and from species to species, but for the purpose of this chapter, the following classification of elemental concentrations has been adopted (17) major, > 1% minor, 0.10-1% micro, 0.01-0.1% trace, 0.01-0.001% ultratrace, < 0.001%. Since total copper in the average, "standard man (18) is approximately 150 mg (2), its classification would fall between trace and ultratrace concentration. However, as is the case with any other element, what is a trace in one organ may be an ultratrace in another, but for serum copper concentration, which is about 100 /xg%, the definition of copper as an ultratrace metal by the above classification may not be justifiable. If the criteria of the "standard man is taken into account, however, the definition seems appropriate. 

Based on reports by other workers in this field and on our own findings, two hypotheses could be postulated to explain the increased serum copper concentration with age. Since tissues in these subjects were not examined for copper concentrations, increased serum copper concentration may either represent an increase in the total body pool of copper or, alternatively, the copper may have shifted from another organ, thus increasing plasma copper, plasma in this instance acting as a vehicle for transiently transporting the metal to other parts of the body where it is needed. 

Table 9.10 Metal concentrations (ng/g) in synovial fluid, serum and urine. Median (range) (Karrholm et ai, 1994)...

Correlations between well-known diseases and changes in trace metal concentrations in serum, cells, or tissue have been detected to an increasing extent. Therefore trace metal determinations may be useful in different diseases, even in the prodromal stage, to prevent trace metal deficiency. In Crohn s disease the serum concentration of zinc and possibly of copper and iron is diminished, metabolic pathways are affected, and partial dermatitis occurs. Zinc supplementation removes skin lesions [52]. In acute and chronic liver diseases serum zinc is reduced and in consequence of biliary hypoexcretion the serum concentrations of manganese and copper are high. 

They are used to soften and purify water, to purify fruit juices, in the separation of metals from each other (for example, separating plutonium and uranium in nuclear reactors), in the manufacture and purification of sugars and in the manufacture of pharmaceutical products. The ion exchange polymers colestyramine, colestipol and colesevelam are also known as bile acid sequestrants and are used to lower serum cholesterol concentrations. They are not absorbed from the intestine, where they bind bile acids, reducing their reabsorption after biliary excretion. The pool of bile acids becomes depleted, resulting in upregulation of cholesterol 7-a-hydroxylase, which increases conversion of cholesterol to bile acids. 

Several studies have suggested that blood aluminum levels, similar to blood levels of other metals, can serve as an indicator only of circulating aluminum levels, and not total body store. Bowdler et al. found an inconsistent relationship between serum and brain aluminum concentrations though there was a correlation in some groups of rats exposed to aluminum chloride, there was no correlation in others. These authors point out that serum aluminum concentration is not necessarily a reliable indicator of... 

The concentration of aluminum in serum can be determined by adding 2-hydroxy-1-naphthaldehyde p-methoxybenzoyl-hydrazone and measuring the initial rate of the resulting complexation reaction under pseudo-first-order conditions.The rate of reaction is monitored by the fluorescence of the metal-ligand complex. Initial rates, with units of emission intensity per second, were measured for a set of standard solutions, yielding the following results... 

Proteins modified with 2-iminothiolane are subject to disulfide formation upon sulfhydryl oxidation. This can cause unwanted conjugation, potentially precipitating the protein. The addition of a metal-chelating agent such as EDTA (0.01-0.1M) will prevent metal-catalyzed oxidation and maintain sulfhydryl stability. In the presence of some serum proteins (i.e., BSA) a 0.1M concentration of EDTA may be necessary to prevent metal-catalyzed oxidation, presumably due to the high contamination of iron from hemolyzed blood. 

Dissolve the antibody to be modified at a concentration of l-10mg/ml in 0.1M sodium phosphate, 0.15M NaCl, pH 7.2, containing 10 mM EDTA. High levels of EDTA often are required to stop completely metal-catalyzed oxidation of sulfhydryl groups when working with serum proteins—especially polyclonal antibodies purified from antisera. Presumably, carry-over of iron from partially hemolyzed blood is the contaminating culprit. 

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