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

The aim of the present investigation was to evaluate abnormal changes in trace element concentrations during carcinogenesis. First, Al, Zn and Cu in the liver tissues of rats were measured by atomic absorption analysis over a half year of hepatocarcinogenesis. Male Wistar rats were given carcinogenic food containing 600 mg/kg of 3'-methyl-4-dimethylaminoazobenzene (3'-MeDAB) in a basal diet for several months. After 4 to 6 months of feeding, hepatocarcinomas developed in the rats. Zn and Cu concentrations in the hepatocarcinomas of the 3'-MeDAB group significantly decreased as compared with normal liver tissues of the control groups. On the other hand, the aluminum concentration in the hepatocarcinomas was more than three times that in the normal liver tissues. The Al and Se contents of developed gastric and mammary cancers were measured in Experiment II. Male and female rats were given 1-methyl-3-nitrothoguanidine(MNNG) and 2,7-dimehtylbenz(a)anthracene(DMBA), respectively. After several months, carcinomas developed in over half of the rats. The Al and Se concentrations in cancers, livers and the blood were determined by atomic absorption analysis. It was shown that both gastric and mammary carcinomas contained a high level of aluminum and very little selenium in comparison with normal liver tissues. The present study demonstrated that aluminum accumulated in experimentally induced carcinomas in rats, i.e., cancers of the liver, stomach, duodenum and mammary glands.

Microgram quantities of dental plaque were taken near amalgam fillings, gold crowns and intact teeth. Such extremely small samples can be analysed by total reflection X-ray fluorescence (TXRF), a fairly new variant of energy dispersive X-ray fluorescence (EDXRF). More than sixty samples were examined directly without chemical pretreatment. Fifteen elements of interest were detected simultaneously within a wide range of mass fraction and with detection limits of several mg/kg. A significant correlation of the Hg-accumulation in plaque and the amalgam fillings was established. Near these fillings Hg mass fractions can reach a level of 300 mg/kg. The results for other elements, e.g. Au, are less significant.

The incidence of subclinical lead (Pb) poisoning was investigated in the cattle population of an industrial area in northern Greece. The cattle were divided into two groups with respect to their alleged exposure to Pb, which was assayed by determining whole blood and hair Pb concentration and erythrocyte delta-aminolevulinic acid dehydratase (ALA-D) activity. The cows which were located closer to potential contamination sources were found to have higher (P < 0.05) blood and hair Pb content, whereas no significant differences were noted in ALA-D activity. Hair Pb increased significantly (P < 0.05) with age, an observation which should lead to further, more extensive research, in order to evaluate the possibility of using hair as indicator of chronic Pb intake.

Adverse effects on hematopoiesis and renal function have been reported in both animals and humans exposed to high doses of lead for a protracted period of time, but little is known about the interrelationship between these two target organ systems. The present study examines rats exposed via drinking water to high dose (5000 mg/L) or low dose (100 mg/L) lead, either continuously or discontinuously, for periods ranging from 1 to 12 months. In addition to blood lead, indices of hematological abnormalities included hematocrit, zinc protoporphyrin (ZPP) and red blood cell (RBC) membrane sodium-potassium-activated adenosine triphosphatase (Na-K-ATPase). Renal function abnormalities were assessed by measurements of glomerular filtration rate (GFR) by the single injection 125-I-iothalamate technique and urinary excretion of the proximal renal tubular enzyme, ligandin. Blood lead and GFR correlated positively during the first 6 months of lead administration, reflecting a stimulatory effect of lead on renal hypertrophy and GFR during this time period. When this distorting effect was factored out, there were few residual correlations between renal and hematological abnormalities. The only significant relationship between GFR and hematological parameters of lead toxicity was a negative correlation between GFR and RBC membrane Na-K-ATPase in animals treated with high dose lead for 6 months and observed at the end of 12 months (discontinuous group).(ABSTRACT TRUNCATED AT 250 WORDS)

To obtain reference values for plasma and erythrocyte selenium concentrations blood specimens were collected from healthy adults from the Bratislava region. In 174 people, 20 to 60 years old, a plasma Se concentration of 56.2 +/- 8.5 micrograms/L and in 133 persons an erythrocyte Se level of 95.3 +/- 16.3 micrograms/kg were found (mean +/- SD). Selenium levels showed a normal distribution in plasma and erythrocytes. No differences were found according to sex or age. These results indicate that the Slovak population has a low Se status, with values for plasma Se being among the lowest in Europe.

The concentrations of trace elements in hair were measured in 108 healthy subjects (60 males and 48 females, mean age 46-years) resident on Atafu (Tokelau) and in 83 subjects (63 males and 20 females, mean age 26-years) living on Kitava island (Papua New Guinea). On Kitava, a traditional subsistence lifestyle uninfluenced by Western dietary habits is still maintained, but on Atafu the dietary habits have been modified by the inclusion of such imported foods as rice, flour, sugar and canned meat and fish. The concentrations of zinc and magnesium in hair were significantly higher in the Kitava than in the Atafu subjects, whereas those of copper were similar in both groups, and those of selenium, mercury, lead and cadmium were higher in Atafu subjects. The levels of serum copper, magnesium and selenium concentrations in Kitava subjects were not so low as to indicate any trace element deficiency. The higher hair content of mercury, lead and cadmium found among Atafu subjects might be due to consumption of marine foods contaminated with metals, consumption of canned foods, or frequent cigarette smoking, though it is difficult to single out any specific factor.

The role of GSH concentration and GSSG reductase activity in age differences in chromate nephrotoxicity was investigated. Young and adult rats were injected with 2 and 1 mg sodium chromate/100 g body weight (BW), respectively, which led to equal Cr concentrations in renal tissue. Cr nephrotoxicity was lower in young than in adult rats. It was shown that from 30 minutes after the chromate injection GSSG reductase activity in renal tissue was increased in adult but decreased in young rats by the chromate. GSSG reductase activity was increased in young rats by pretreatment with phenobarbital. The consequence was an enhancement of chromate nephrotoxicity as shown by proteinuria. Renal GSH concentration is lower in young rats and limiting for chromate reduction in vitro in these animals. Therefore, GSH concentration was increased by pretreatment with N-acetylcysteine, which enhanced chromate nephrotoxicity significantly. These results reflect the important role of the GSH oxidoreduction system in chromate nephrotoxicity and its relationship to age differences.

In this study we determined the serum selenium concentraction of 218 healthy individuals at different ages, in Ankara, using a spectrofluorimetric method. The mean selenium levels were found to be 45 +/- 10 micrograms/L in cord blood at birth; 69 +/- 13 micrograms/L in 2 month-12 month-old infants; 77 +/- 12 micrograms/L in children aged > 12 months-16 years; and 74 +/- 16 micrograms/L in adults aged 18-48 years. Selenium concentrations showed age dependency, increasing significantly in childhood but decreasing after 40 years of age. No relation to the sex, dietary habits, socioeconomical status or hematological parameters such as hemoglobin concentration and white blood cell count, was observed. The results obtained thus suggest that the status of selenium in Ankara residents is in a range that could be considered as safe and adequate.

Human milk is believed to provide all the nutrients necessary for normal infant growth. The present study is concerned with the evaluation of longitudinal changes in Fe, Cu, Zn, Se, Br, Pb, Rb, and Sr milk contents over a long period of lactation. A total of 140 milk samples from 26 lactating mothers were supplied from the 2nd to the 180th day after delivery of a full-term healthy infant. Cu, Zn, and Se showed a time-dependent decrease, with similar 10-day half-times. Br and Pb showed correlations with time, but the data fitting produced very short (2-3 days) half-times. The Fe, Rb, and Sr contents were constant over the lactation time. After about one month of lactation, trace element contents tend to stabilise, as do other milk components.