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

An external quality assurance scheme for Cu and Zn analysis in serum was carried out in Italy between 1989 and 1990. It included: preparation of control materials by the organizing centre; distribution of control samples to the participants according to a random selection; elaboration of results and evaluation of laboratory performance. Inter-laboratory variability was 16.9% and 16.4%, at concentrations of 0.94 and 1.08 mg/l, for Cu and Zn, respectively. Laboratory performance in terms of percentage of results within the limits of acceptability, improved for Cu, but not for Zn analysis.

The concentrations of zinc, copper, nickel and chromium were determined in bone marrow and plasma of 37 patients suffering from non-Hodgkin-lymphomas (NHL). The results were compared with a control group of 10 patients with negative histopathologic results in bone marrow. The results demonstrate that all patients with low grade and high grade NHL have elevated trace element levels in bone marrow compared to the control group. In plasma there are also differences in the trace element levels of patients with NHL compared to the control group; the levels, however, are partly higher and lower than those of the control group. Altogether the plasma level differences are not as noticeable as those in the bone marrow. At the moment it is not yet possible to draw final conclusions from these results for the prognosis or therapy of NHL, but the study tends to show that intracellular measurement of trace elements is more reliable than intraplasmic measurement.

Healthy elderly persons were selected according to an admission protocol which included clinical, hematological and biochemical parameters. Plasmic levels of zinc in these subjects were in the normal range, while plasmic copper was higher than that of young controls. The number of circulating lymphocytes and CD3+ cells was decreased; however, the absolute number of CD4+, CD8b, CD8d, CD20+ and CD57+ cells did not differ from that of controls. A decreased lymphocyte response to PHA in serum-free medium cultures was also observed in the healthy elderly persons.

Recent epidemiological and experimental research indicates that toxic and carcinogenic effects of certain trace elements including metals may occur at levels compatible with exposure in the general environment. Despite a large number of studies describing metal cytotoxicity, the molecular mechanisms involved are still poorly understood. However, it now appears clear that several metals can interact with proteins involved in signal transduction, including Ca2+ channels and pumps. The resulting impairment of the ability of cells to respond adequately to the stimulation by hormones and growth factors results in the loss of important cell functions and can ultimately compromise cell survival.

Selenium and the selenium-dependent glutathione peroxidase (GSH-Px) were measured in healthy and diabetic children from Germany and Hungary. Hyperglycemia and hyperlipidemia are present in diabetes mellitus and they are associated with increased lipid peroxidation. The selenium content of erythrocytes, whole blood and plasma, as well as of plasma glutathione peroxidase activity, were found to be low in the healthy Hungarian children compared to the healthy Germans. Both groups of diabetics had significantly higher blood selenium (1.05 +/- 0.14 versus 0.86 +/- 0.1 mumol/L in Hungarians, 1.34 +/- 0.21 versus 1.12 +/- 0.22 mumol/L in Germans) and higher plasma selenium (0.89 +/- 0.15 versus 0.68 +/- 0.01 mumol/L in Hungarians and 1.01 +/- 0.2 versus 0.88 +/- 0.19 mumol/L in Germans) than the healthy children of the same countries. In all diabetic children the plasma glutathione peroxidase activity and triglycerides were higher and the plasma HDL-cholesterols (HDLC = high density lipoprotein-cholesterol) lower than those in healthy controls. The patients showed linear correlations between blood glucose and plasma glutathione peroxidase activity, as well as in erythrocyte glutathione peroxidase activity with triglycerides (TG) and an inverse correlation with HDL-cholesterol. Plasma selenium correlated only in healthy children with triglycerides, cholesterol and HDL-cholesterol. Irrespective of the geographical region diabetics had a higher selenium status than healthy children. In addition, we found correlations between selenium and lipoproteins in the reference group. The mode of glycation, oxidative procedures and the selenium binding to lipoproteins could explain the different associations in the healthy and diabetic children.

There are three selenium-containing proteins in human plasma: glutathione peroxidase (GSH-Px-P), albumin and selenoprotein Ph, the human analogue to selenoprotein P from rat plasma. Selenoprotein Ph was separated from the two other selenium-containing proteins by Heparin Sepharose chromatography and was shown to have about 60-70% of the total plasma selenium, while both GSH-Px-P and albumin contain about 15%. A 2588-fold purification from human plasma was achieved by using a four-step procedure. SDS-PAGE of the purified selenoprotein revealed, besides one contaminant selenium-free protein band at about 70 kDa, one selenium-containing band ranging from 54 to 67 kDa with a maximum at 63 kDa. This microheterogeneity, also recognized by IEF, may be due to the glycprotein nature of the selenoprotein Ph. The determination of the molecular mass of the native protein varied from 65 kDa using gel filtration on Fraktogel HW 55 to 89 kDa on Sephacryl S-200 HR, suggesting an interaction between the gel-matrices and selenoprotein Ph.

Selenium (Se) was determined in human milk from women residing in Niamey (Niger) at different periods of lactation. To this purpose, a rapid electrothermal atomic absorption spectrometric (EAAS) method using Zeeman background correction and palladium matrix modifier was developed. Linear range (10 nmol/L-6.25 mumol/L, 0.8-494 micrograms/L), within-run (7.6%), between-run (10.4%), precision and recovery of standard addition (101 +/- 7%) were sufficient to allow routine determination of Se in breast milk. Values of breast milk Se decreased from 5 days to 6 months postpartum. No significant correlation was found between the milk Se and any of the following parameters: mother serum Se, parity, age of the mother, age of the previous child. In mother serum, Se concentration increased from delivery to 3 months postpartum and remained stable afterwards. The Se concentrations found in breast milk and in mother serum suggest that Se status is adequate in Niger.

This study reports plasma and total blood cell (TBC) Cu and Zn levels of 16 runners before and after a marathon race. All the pre-race plasma values were in the normal range, while the TBC Cu level was 29.3% (P < 0.01) lower and the TBC Zn level was 29.5% (P < 0.01) higher than mean values of the control group. The run induced a significant decrease in TBC Cu concentration during the days following the race and a light increase in plasma Cu values. It caused a significant increase in TBC Zn concentration at the end of the race (followed by a decrease 24 hours later) without plasma Zn variations. These data show that intense physical exercise could modify trace-element metabolism.

A digestion procedure for selenium determination by hydride generation atomic absorption spectroscopy (AAS) in whole blood, serum and urine is described, it employs sulfuric acid, hydrogen peroxide and vanadium (V) sulfuric acid reagent solution. The method is rapid, uses no explosive reagents and can be performed at a constant temperature of 100 degrees C. Therefore, it is easily applicable in a routine clinical laboratory for a large amount of samples. The coefficient of intra-assay variation was 4.3-5.6%, the coefficient for inter-assay variation was 5-5.9% in the medium and high concentration range, and 5.8-8.6% in the low range. In analyzing several commercial reference materials our results showed good agreement with the target values. Analytical recovery by addition of sodium selenite and seleno-DL-methionine to samples ranged between 97 and 104%. The correlation between the described digestion procedure and the nitric, sulfuric and perchloric acid digestion procedure recommended by the International Union of Pure and Applied Chemistry showed good agreement for whole blood, serum and for urine. We determined selenium in serum (n = 58) and whole blood (n = 50) in a collective of healthy children from 1 to 5 years living in Styria, Austria. The low values in serum (35 +/- 11 micrograms/L) and whole blood (42 +/- 6 micrograms/L) at one year of life increased significantly to 48 +/- 13 mu/L (p = 0.033) and 55 +/- 6 micrograms/L (p = 0.004) at three years of life in serum and whole blood, respectively. The selenium concentration showed no further increase up to five years of age.(ABSTRACT TRUNCATED AT 250 WORDS)