Journal of trace elements and electrolytes in health and disease最新文献

The aim of the present study was to investigate whether the level of selenium and selenium/vitamin E supply influences the humoral immunity of rats. In order to detect the effect of Se supply and age, 36 weaned Sprague-Dawley rats divided into two equal groups were killed after 22 or 45 experimental days by decapitation (Exp. I). In Exp. II 9 groups of 10 rats each were exposed to each combination of deficient, normal or excessive selenium with a vitamin E supply and killed after 44 days. The basic (deficiency) diet which was the same in both experiments contained 0.04mg Se and 8mg vitamin E per kg dry matter. The supplementation per kg diet was 0 or 0.2mg Se and 30mg vitamin E in Exp. I and 0, 0.2 or 1mg Se and 0, 30 or 200mg vitamin E in Exp. II. The concentration of selenium in serum, liver and spleen samples and the activity of glutathione peroxidase, which were determined to define the selenium status of the animals, corresponded well to the required supply situation. The immunoglobulins of type IgA, IgM and IgG with the subtypes IgG1, IgG2a, IgG2b and IgG2c were measured by immunoelectrophoresis. In both experiments selenium deficiency decreased the values of the IgG groups only nominally, IgA was not changed. IgM was significantly reduced, especially with prolonged selenium deficiency and simultaneous vitamin E deficiency. An excessive selenium supply compensated to a great extent for the effects of vitamin E deficiency on IgG and IgA.

The concentrations of calcium, magnesium, zinc, copper, free fatty acids and total, HDL- and LDL-cholesterol in the sera of atherosclerotic men were determined. The subjects with femoral atherosclerosis were divided into two age groups: 35-59 years (N = 8, I) and 60-75 years (N = 8, II). The LDL-cholesterol concentration was increased in the elderly atherosclerotic group. Lower concentrations of calcium and magnesium, a higher concentration of copper and decreased Ca/Cu, Mg/Zn, Mg/Cu and Zn/Cu ratios were found in atherosclerosis I as compared to controls of the same age. High and positive correlations for Cu vs. total cholesterol and LDL-cholesterol (r > 0.89), but low correlation for Cu vs. HDL-cholesterol (r = 0.61) were calculated in atherosclerosis I, and negative correlations for free fatty acids vs. Ca and Mg (-r > 0.77) in atherosclerosis II.

The concentration of the microelement cobalt in the urine of healthy children and of children with increased arterial pressure was studied. The values of the cobalt content in the urine of clinically healthy children were 0.22 +/- 0.06 mumol/l in boys and 0.21 +/- 0.11 mumol/l in girls, which were taken as normal, while the values in children with increased arterial pressure were 0.39 +/- 0.17 mumol/l in boys and 0.28 +/- 0.06 mumol/l in girls, which are considered to be increased. These results were explainable by incomplete assimilation and excretion of a great part of the cobalt in the urine of children with elevated arterial pressure (AP).

ICP-MS is a powerful analytical technique for the determination of trace and ultra-trace elements in biological materials. Results are given of the analysis of human serum and of several biological reference materials (bovine liver, milk powder, wheat flour and pig kidney). Because concentrations of many trace metals of interest in these materials are low, dilution should be kept as limited as possible, although concentrations of certain concomitant elements (e.g. Na, K) can be high enough to cause significant suppression or enhancement of the ion signal. The result is that the dissolution procedure becomes a critical step in the analysis. Microwave digestion, wet digestion with several acids (HNO3, HClO4, HF) and simple dilution are compared with each other. In addition, three possible approaches to overcome these problems are discussed, namely the internal standardization method, the standard addition method and the isotope dilution method. Furthermore, ICP-MS is also more susceptible than initially expected to isobaric interferences arising from the plasma, the acids used in the sample preparation or the sample itself. These interferences are generally less important above a mass number of 80. Nevertheless, several researchers have investigated the possibility of removing the trace metals from the matrix or of using correction formulae based on the isotopic abundances of the elements. Some of these are evaluated. The need for identifying and quantifying chemical species, not just the elements, is well recognized. One of the reasons why elemental determination may not suffice is that different species of the same element may have a different chemical and toxicological behaviour. Arsenic (As(III), As(V)) and mercury (organomercury) are typical examples.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of dietary selenium (0.03 mg/kg and 0.31 mg/kg), and fat (5% and 20% corn oil) on antibody formation in the neonatal rat was studied at two different time periods using four diets. The latter were fed to dams throughout pregnancy and lactation and to their pups starting at day 18. A week later, pups received intraperitoneal injections of the test antigen, fluorescein-bovine serum albumin in complete Freund's adjuvant (150 micrograms per 30 g body wt.). On days 7 or 9 post-injection, the pups were sacrificed. The antibody titer, as determined by the quenching of fluorescein by the test sera, and by ELISA, almost doubled from day 7 to day 9 (p < 0.05). There was no significant difference in antibody titers between dietary groups except at day 9 post-injection. Using ELISA, pairwise comparisons indicated that addition of 0.3 mg/kg Se to high fat diet was associated with low antibody titer (p < 0.05).

A normocalcemic animal model of vitamin D (vit. D)-deficiency has been successfully developed by feeding a high calcium (Ca2+) diet to vit. D.-deficient rats. The modulating role of Ca2+ on the hepatic antioxidant defence system and lipid peroxidation has been evaluated in this model. Partial restoration of liver function was noted in these rats following extra Ca2+ feeding. Serum alkaline phosphatase and alanine aminotransferase reverted to a normal level. The reduced levels of hepatic SOD and glutathione peroxidase in vit. D.-deficient rats, were also increased after extra Ca2+ supplementation. Even elevated lipid peroxidation due to vit. D.-deficiency was reduced after feeding the extra Ca(2+)-supplemented diet. However, catalase activity remained at the control level throughout the study. The results provide important evidence that normocalcemia is essential for maintaining the hepatic antioxidant defence and controlling lipid peroxidation in the in vivo milieu.

An investigation was undertaken in order to assess Al concentration levels in infant formulas. Eligibility criteria were defined and strictly adhered to. An overall strategy was worked out to guarantee reliability and representativity of experimental data, in particular by minimizing all possible sources of chemical contamination or loss. The study was carried out by means of Inductively-Coupled Plasma Atomic Emission Spectrometry (ICP-AES). In cow's milk-based infant formulas as made up for consumption (about 13% in the final solution), Al levels of between 0.03-0.85 mg/L were detected. Higher amounts were present in soya-based formulas, with concentrations ranging from 0.39 to 1.01 mg/L.

Renal retention of selenium after administration of trimethylselenonium iodide (TMSeI) was studied in vivo in male and female rats during sexual maturation. The selenium level in the kidneys was found to be significantly higher in male rats than in females during the first hour after intravenous (i.v.) administration of TMSeI. The sex-linked difference, manifested already in 21-day old animals, increased markedly during the following four weeks of postnatal life. It was shown that this process may be accelerated by previously increased selenium intake. The sex-linked difference in renal retention of selenium was observed after administration of TMSeI in a wide range of doses: 0.002-10.0 mumol per animal. The size of the applied dose did not affect significantly the kinetic patterns of selenium in the kidneys during the first hour after i.v. injection. The results suggest the existence of a sex-dependent mechanism in the kidneys which may control the rate of excretion of trimethylselenonium ions in urine both under conditions of normal selenium intake and selenium intoxication.