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

This report is a summarization of preliminary results from a study of dietary Se intake in a seleniferous area in order to determine safe levels. All patients have symptoms of toxicity: broken hair strands or various levels of nail damage. Finger-nail signs were the first symptoms used for diagnosis of selenosis in this work. Based upon the lowest blood-Se level of five subjects with persistent overt finger-nail signs of selenosis, it was found in 1986 that the individual marginal toxic blood Se level (LOAEL) and the corresponding Se intake were 1054 micrograms/L and 910 micrograms/d, respectively. To re-examine the clinical signs and blood Se levels of the five individuals and to see how the two are correlated, a study was conducted in July 1992 at the same location in the seleniferous area. The results showed that along with the absence of clinical signs, the average blood Se level had decreased from 1346 to 968 micrograms/L. The corresponding safe Se intake per day would be 819 +/- 126 micrograms (15 micrograms/kg B.W. or approximately 800 micrograms per day, which is suggested as the mean No Adverse Effect Level (NOAEL), and the lower limit of the 95% confidence interval, 600 micrograms per day would approximately the maximum individual safe Se intake. For safety, 400 micrograms is again proposed as the Maximum Safe Daily Dietary Se Intake. Problems inherent in this estimation have been discussed.

In a total number of 275 dogs of various ages, sex and breed, blood lead concentrations (BLC) and erythrocyte ALAD activity were measured. Sixty-six of the dogs were living in lead mining areas (Group A), 157 in urban areas (Group B) and 52 in rural areas (Group C) of Greece. Mean BLC differed significantly (P < 0.05) between locations and were 326,97 and 68 micrograms/L, respectively. Mean ALAD activity was significantly different (P < 0.05) only between Groups A and B as between groups A and C. A significant (P < 0.05) negative correlation existed between BLC and ALAD activity. A normal range of erythrocyte ALAD activity of 807-992 mumol/PBG/LRBC/h was established for dogs. None of the 33 Group A dogs and 2 of the Group B dogs that had a BLC of 350 micrograms/L presented clinical signs indicating acute or chronic lead intoxication. No erythrocyte basophilic stippling or large number of nucleated red blood cells were seen in the 30 dogs of Group A with BLC > 350 micrograms/L.

The effects of supplementary oral cobalt and iron, as well as the interaction between both at the absorption site, fecal and urinary excretion as well as the retention of these trace elements were determined by using four diets containing either 9 or 63 micrograms/kg of Co and 48 or 446 mg/kg of Fe over a period of 19 days in a total of 24 rats. Retention was calculated by the balance technique and by the comparative slaughter technique. After one day, fecal as well as urinary excretion of both elements had already responded to the dietary treatments, with constant values being reached after approximately three days. Cobalt excretion was enhanced by supplementary cobalt; fecal excretion, too, was increased by supplementary iron; whereas urinary excretion was decreased in both cases. Additional iron significantly inhibited the absorption of cobalt in both dietary cobalt treatments. The lower rate of absorption in the groups receiving 446 mg Fe instead of 48 mg of Fe per kg diet resulted in a decreased renal excretion of cobalt. Consequently, the effect of iron on the retention of cobalt was lower than on absorption. This suggests that interactions between the two elements only take place at the site of absorption. Because of the low dietary cobalt concentration as compared to the iron contents of the diets, no effect of cobalt on iron absorption and excretion occurred. Differences in iron balance were only observed between both dietary concentrations, showing a higher absolute but a lower relative absorption as well as retention in the groups fed further Fe.(ABSTRACT TRUNCATED AT 250 WORDS)

In this pilot study the concentration of cadmium was determined quantitatively in samples of renal cortex of 22 kidney cancer patients and 19 controls. Data on the three main sources of exposure to cadmium-diet, cigarette smoking and occupation-were obtained through interviews. No significant difference in Cd concentration between the tumor samples and the controls could be found. The mean Cd concentration was 50.9 +/- 25 mg/kg dry weight for cancer patients and 55.2 +/- 50 mg/kg for controls. Further, it was established that the age-dependent relationship for cadmium in the cortex was not valid for smokers.

The influence of 14 metal ions on free radical (FR) formation in subcellular systems of lung mitochondria and brain synaptosomes (cortex and cerebellum) of rats was investigated. Iron and manganese showed a highly significant increase in FR formation in lung, whereas other investigated metal ions showed relatively slight, insignificant decreases in FR. The significant enhancement effects of iron and manganese increased with their content in the media. Scandium exhibited an insignificant enhancement effect at a low concentration of 0.01 microM, but also an insignificant decrease in FR formation in lung at higher concentrations. In brain cerebellum only iron significantly increased FR formation but manganese, as well as trivalent metals (Al, La, Sc), showed insignificant changes in FR formation. The possible causes of differences induced by metal ions at various concentrations, as well as the biological functions of the investigated tissues, were considered in the explanation of obtained results.

Although several studies have described an increase in urinary zinc output in cancer patients, little attention has been paid to the excretion of copper. In this study, we investigated urinary excretion of zinc and copper, and serum levels of alpha-1 acid glycoprotein, an acute phase protein, in 22 patients with colorectal cancer. Urinary excretion of copper and zinc were significantly increased compared to the reference group (77 +/- 72 vs. 32 +/- 14 mumol/mol creatinine, P < 0.05, and 1.50 +/- 0.62 vs. 0.70 +/- 0.41, P < 0.002, respectively). In addition, a negative correlation was observed between urinary copper and serum alpha-1 acid glycoprotein (rs = -0.5256, P < 0.02). In conclusion, urinary excretion of copper, as well as that of zinc, appears to be elevated in colorectal cancer. The finding of a negative correlation between urinary copper and alpha-1 acid glycoprotein supports the postulated role of the latter in regulating renal glomerular permselectivity.

In the present study, the effect of zinc deficiency on erythrocyte membrane lipids of force-fed rats that received either a diet with coconut oil and safflower oil (86:14, w/w) or a diet with fish oil and safflower oil (91:9, w/w) was investigated. Zinc deficiency caused in the rats fed both types of dietary fat an increase in the amounts of total phospholipids and individual phospholipid classes in erythrocyte membranes. In the rats fed the coconut oil diet, zinc deficiency caused an increase in the proportion of docosahexaenoic acid (22:6) in phosphatidylcholine (PC), diacyl phosphatidylethanolamine (PE), phosphatidylserine (PS), and in total erythrocyte membrane fatty acids. In contrast, in the rats fed the fish oil diet, zinc deficiency caused an increase in the proportion of docosahexaenoic acid only in PC, but not in the other phospholipids. However, in these rats, changes in the ratio between eicosapentaenoic acid (20:5) and the n-3 fatty acids with 20 and 22 carbon atoms were observed in PC, diacyl PE and plasmalogen PE. The most pronounced changes in fatty acid composition due to zinc deficiency in the rats fed both types of fat occurred in PC. There was a relationship between the changes in the composition of plasma total fatty acids and the changes in fatty acid composition of erythrocyte membrane PC caused by zinc deficiency in the rats fed both types of dietary fat. The amount of cholesterol was similar in all treatment groups. However, zinc-deficient rats fed the coconut oil diet-but not those fed the fish oil diet-had an increased ratio between total phospholipids and cholesterol. Thus, the study shows that the effect of zinc deficiency on erythrocyte membrane lipids is to some degree similar for rats fed a coconut oil diet and rats fed a fish oil diet, and to some degree different.