Trace Elements and Metallothionein in Liver and Kidney of <Emphasis Type="Italic">Felis catus</Emphasis>

Trace metals such as Zn, Cu, and Fe are essential for life; differently, no biochemical function is known for Cd. Changes in dietary metal concentrations can cause deficiency or toxicity. Studies on trace elements in cat are lacking. This paper aimed to analyze Zn, Cu, Fe and Cd concentrations in liver and kidney of pathological domestic cat and to isolate metallothionein (MT) in these tissues. It was not possible to explore a possible correlation between metal concentrations and pathologies because the incidence for each of them was too low. Fe was the most abundant metal; in particular, the liver accumulates average Fe concentrations one order of magnitude higher than Zn and Cu, ranging from 66.75 and 1,444.23 μg/g. Significantly, higher levels of Fe were found in the liver of elder animals. Zn concentrations varied between 26.31 and 84.78 μg/g in the liver whereas in the kidney, ranged between 7.69 and 71.15 μg/g. Cu concentrations were between 2.37 and 112.91 μg/g in liver and between 2.12 and 9.85 μg/g in kidney. Cd was the least abundant metal with the exception of the kidney of the oldest cats where it reached a maximum of 13.71 μg/g. Gel-filtration metal distribution profiles from cytosolic extracts revealed the presence of Cd, Cu, Zn thioneins either in the liver or in the kidney. Because tissue samples were taken from pathological cats from different breed and age, care must be taken to use these data as a baseline profile of trace elements in healthy animals. Our results are indicative that for some specimens the feed levels of Fe and Cu could be higher than the optimal dietary intake and in few cats, there was also an exposure to Cd that was counteracted by MT biosynthesis.     

Concentrations of cadmium,zinc, copper,iron, and metallothionein in liver and kidney of nonhuman primates

To evaluate the species specificity of Cd accumulation and the relationship of Cd with other essential metals and metallothionein (MT), the concentrations of Cd, Zn, Cu, and Fe in the liver and kidney and the MT concentrations in the soluble fractions of the liver and kidney were determined in Cd-uncontaminated nonhuman primates (11 species, 26 individuals) kept in a zoo and two wild-caught Japanese macaques. The compositions of metal-binding proteins in the soluble fractions were also investigated by high-performance liquid chromatography (HPLC). The hepatic Cd concentration was 0.03–14.0 μg/g and the renal Cd concentration was 0.35–99.0 μg/g, both varying greatly and being higher in nonhuman primates, which were more closely related to man. The hepatic Zn concentration was 24.0–176 μg/g and the renal Zn concentration was 13.5–138 μg/g, showing 7- to 10-fold differences, and a correlation (r=0.558, p<0.01) was found between renal Zn and renal Cd concentrations. It was proved that in the liver, MT is more closely correlated with Zn (r=0.795, p<0.001) than with Cd (r=0.492, p<0.01) and that in the kidney MT is correlated with both Cd (r=0.784, p<0.001) and Zn (r=0.742, p<0.001). HPLC analysis of metals bound to MT-like protein in chimpanzees, de Brazza’s monkeys, and Bolivian squirrel monkeys showed that more than 90% of Cd in both the liver and kidney, approx 40% of Zn in liver and 28–69% of Zn in kidney were bound to MT-like protein. The higher percentage Zn was bound to high-molecular protein.     

Variation in the distribution of trace elements in hepatoma

There are many reports of reduction of zinc level and rise of copper level in serum of patients with liver disease. However, there are a few reports that compare the trace elements in tumor tissues and nontumor tissues of the liver with hepatoma. We studied trace element distribution in tumor tissues and nontumor tissues of liver with hepatoma and compared them with data from normal liver tissues. Zinc (Zn), copper (Cu), selenium (Se), cadmium (Cd), mercury (Hg), and iron (Fe) were chosen as the trace elements to be observed. We observed falls of Zn, Cd, and Hg levels in tumor tissues and the rise of Cu level as a result of this investigation. Zn, Cd, and Hg levels in tumor tissues were significantly lower than those in nontumor tissues and Zn, Cd, and Hg levels in nontumor tissues were significantly lower than in normal liver tissues. This tendency was clearer for Cd and Hg than for Zn. Although the distribution of Cu was not significant, a distribution contrary to that of Zn was shown. These findings indicate that the distribution of Zn, Cd, and Hg can serve as supportive evidence that could be useful as a tumor marker. Selenium showed almost the same accumulation tendency among tumor tissues, nontumor tissues, and normal livers. Although correlation was observed among most metals in the normal liver, there was almost no correlation in tumor tissues.     

The fate of Cd,Cu, Ca,Zn, and Fe in rat during the recovery period following cessation of repeated exposure to Cd

Cadmium was administered subcutaneously to male Wistar rats, 0.1 mL/rat in 0.9% saline 3 times a wk for 4 wk at 3 mg Cd/kg. Saline was administered to control animals in an equivalent manner, without Cd. After the end of the dosing period, the distribution and excretion of Cd, Cu, Ca, Zn, and Fe were observed in some organs and excreta for 35 d (1, 7, 14, 21, 28, and 35 d). Cadmium dosing caused significant disturbances in the metabolism of Zn, Cu, Fe, and Ca, especially during the recovery period. Growth in Cd-dosed animals did not accelerate, even after 5 wk of recovery. There was evidence of mobilization of some elements among organs. Accumulation of Cd occurred in liver, kidney, and spleen during dosing, and during the recovery period it was retained in kidney and testes (for 2 wk) and cleared steadily in liver and RBC (for 5 wk), but increased in spleen (first 3 wk). The pattern of Cd excretion was closely associated with the binding of Cd with metallothioneins in kidney and liver for the first 21 and 7 d, respectively. This was associated with the excretion of Cd-metallothioneins (Cd-MT) in urine from d 1 to 21 during recovery. Cadmium caused higher Ca accumulations in testes and liver, which were probably associated with the lesions observed in these organs. Significant increases of Cu (in kidney d 7) and Fe (in liver) were observed during recovery. Furthermore, significant reductions of Cu and Fe were found in plasma, spleen, and RBC (after 5 wk) and kidney, spleen, and testes (on d 7), and blood (after 5 wk).     

Reference values for the concentrations of As,Cd, Co,Cr, Cu,Fe, I,Hg, Mn,Mo, Ni,Pb, Se,and Zn in selected human tissues and body fluids

This report attempts to formulate reference ranges of elemental concentrations for 15 trace elements in selected human tissues and body fluids. A set of samples consisting of whole blood, blood serum, urine, milk, liver, and hair were chosen and considered for 15 elements of biological significance: As, Cd, Co, Cr, Cu, F, Fe, I, Hg, Mn, Mo, Ni, Pb, Se, and Zn. The results represent wholly or partially data received from 40 countries of the global regions of Africa, Asia, Europe, North, South, and Central America, Australia, and New Zealand. This survey, even if qualitative, has been useful in demonstrating certain trends of trace-element scenarios around the world. It is of course recognized that both diet and environment exert a strong influence on the distribution pattern of several elements, such as As, Cd, Mn, Pb, Se, and Zn. A limited comparison of the available information on soil status of different countries reflected some interesting associations for elements, such as Mn and Zn. Importantly, this study revealed that only a few countries were in a position to identify a reasonable amount of data on samples requested for this project. Regretably, for a number of countries, any dependable data for even such essential elements as Cu, Fe, and Zn were not available. In view of the nutritional importance of many elements, the time is ripe for concerted efforts by intergovernmental agencies to initiate investigations or commission task forces/projects to generate reliable reference data for selected global regions, which sadly lack data of any kind at present.     

Heavy metal accumulation in iron plaque and growth of rice plants upon exposure to single and combined contamination by copper, cadmium and lead

A pot experiment was conducted to evaluate the bioaccumulation of heavy metals and growth response of rice plants after exposure to single and combined contamination by Cu, Cd and Pb. The results showed that the biomass production was not significantly affected by either single or combined treatment of Cu, Cd and Pb. Adding Cu (Cd, or Pb) separately all increased concentrations of the respective element in root and shoot (p < 0.001). In the combined contamination, Pb promoted both root and shoot absorption of Cu and Cd (p < 0.001), and Cu affected Cd and Pb absorption in the root, but Pb concentrations in both root and shoot were not affected by Cd application. The formation of iron plaques varied obviously with soil types. Heavy metal accumulation in iron plaques was induced by the three elements (p < 0.001). Furthermore, the three heavy metals exhibited an interactive relationship as measured by the Cu, Cd, Pb and Fe concentrations in root surface iron plaques. The iron plaques partially inhibited transfer of Pb to root and shoot, but no such effect was observed for Cu and Cd. This research indicates that the interaction among different heavy metal elements is very complex. It is very important to have a clear understanding on the associated mechanism and the consequential impact on plant growth.     

Heavy metal accumulation in iron plaque and growth of rice plants upon exposure to single and combined contamination by copper, cadmium and lead

A pot experiment was conducted to evaluate the bioaccumulation of heavy metals and growth response of rice plants after exposure to single and combined contamination by Cu, Cd and Pb. The results showed that the biomass production was not significantly affected by either single or combined treatment of Cu, Cd and Pb. Adding Cu (Cd, or Pb) separately all increased concentrations of the respective element in root and shoot (p < 0.001). In the combined contamination, Pb promoted both root and shoot absorption of Cu and Cd (p < 0.001), and Cu affected Cd and Pb absorption in the root, but Pb concentrations in both root and shoot were not affected by Cd application. The formation of iron plaques varied obviously with soil types. Heavy metal accumulation in iron plaques was induced by the three elements (p < 0.001). Furthermore, the three heavy metals exhibited an interactive relationship as measured by the Cu, Cd, Pb and Fe concentrations in root surface iron plaques. The iron plaques partially inhibited transfer of Pb to root and shoot, but no such effect was observed for Cu and Cd. This research indicates that the interaction among different heavy metal elements is very complex. It is very important to have a clear understanding on the associated mechanism and the consequential impact on plant growth.     

Effects of polyphenol-rich plant products from grape or hop as feed supplements on iron,zinc and copper status in piglets

Polyphenol-rich plant products as feed supplements have been shown to exert beneficial effects on feed efficiency in piglets. However, tannins as components of polyphenol-rich plant products are able to reduce the absorption of various trace elements. The present study investigated the effect of two polyphenol-rich dietary supplements, grape seed and grape marc meal extract (GME) and spent hops (SH), on iron (Fe), zinc (Zn) and copper (Cu) status in piglets supplied adequately with those trace elements. A trial with three groups of piglets which received a Control diet or the same diet supplemented with either 1% GME or 1% SH over a period of 4 weeks was performed. Concentrations of Fe, Zn and Cu in plasma, total iron binding capacity and saturation of transferrin in plasma did not differ between the three groups. Piglets fed the diet supplemented with SH showed no differences in the concentrations of Fe, Zn and Cu in the liver in comparison to the Control group. Piglets fed the diets supplemented with GME showed slightly lower concentrations of Zn and Cu in the liver than Control piglets (p < 0.05); however, concentrations of both elements remained in the physiological range. Overall, this study shows that the polyphenol-rich plant products GME and SH had marginal effect on the status of Fe, Zn and Cu in piglets.     

Effect of automobile exhaust on the distribution of trace elements and its modulation following Fe,Cu, and Zn supplementation

The effect of automobile exhaust on the distribution of trace elements with special reference to Pb and its modulation following Cu, Zn, and Fe supplementation, in mouse organs, has been studied using Energy Dispersive X-ray Fluorescence technique. Seven elements, namely K, Fe, Cu, Zn, Br, Rb, and Pb, were detected in all the organs. The maximum concentration of Pb was found in lungs followed by that in liver and kidney. The effect of automobile exhaust was found to be significant on the concentrations of Fe and Pb; their concentrations were found to increase in all the organs. However, the concentrations of Cu and Zn were found to be decreased significantly in the liver. In the animals given Fe, Cu, or Zn supplementation along with motor exhaust, the percentage change in the concentration of Pb in lungs was decreased, and that of Fe was increased significantly. In kidney, no significant change was observed for the animals given Cu and Zn, whereas for animals given Fe, the level of Pb decreased significantly. In liver, the reduction in the level of Zn in the exhaust-exposed animals was made up and the level of Pb was reduced following Zn supplementation. These results clearly indicate that Fe and Zn play an important role in Pb metabolism and tend to lower the absorption of Pb. The effect of Fe is more pronounced than that of Zn, whereas the effect of Cu seems to be insignificant.     

Distribution of elements in rabbit liver lobule

The elemental composition of rabbit liver was determined by the PIXE and micro-PIXE methods. The mean concentrations of P, S, Cl, K, Fe, Cu, Zn, and Rb measured by both methods were similar. The latter method also allowed for localization of elements within lobule territory. It has been found that some elements are more prevalent in the veins (Cl, Fe) and others in the liver parenchyma (P, Cu, Zn). Moreover, Zn showed the characteristic intralobular distribution. Some methodological aspects of microbeam application to biological materials were also discussed.     

Alterations of serum selenium, zinc, copper, and iron concentrations and some related antioxidant enzyme activities in patients with cutaneous leishmaniasis

The aim of this study was to measure the alterations in serum selenium (Se), copper (Cu), zinc (Zn), and iron (Fe) concentrations and their carrier proteins, ceruloplasmin (Cp), transferrin (Tf) albumin, and related antioxidant enzyme activities, erythrocyte Cu-Zn Superoxide dismutase (Cu-Zn SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities in patients with cutaneous leishmaniasis (CL). Erythrocyte Cu-Zn SOD activities, serum Cu concentrations, and Cp levels were found to be significantly higher in the patients group than those of controls. However, GSH-Px and CAT activities and Se, Zn, Fe, and Tf levels were lower in patients than in the control subjects. There were positive important correlation’s between Cu-Zn SOD and Cp, Cu-Zn SOD and Cu, Cp and Cu, GSH-Px and Se, and Fe and CAT in the patients group. Our results showed that serum essential trace elements Se, Zn, Cu, and Fe concentrations and their related enzymes Cu-Zn SOD, GSH-Px, and CAT activities change in CL patients. The changes may be a part of defense strategies of organism and are induced by the hormonelike substances.     

Cadmium,iron and zinc interaction and hematological parameters in rat dams and their offspring

The effects of cadmium (Cd) were evaluated in offspring exposed from birth until weaning (neonatal day 0–21) and 4 weeks after exposure cessation focusing on iron (Fe) and zinc (Zn) levels in organs and hematological parameters. Wistar female rats were administered 50 mg Cd/L in drinking water (Cd-exposed) for 4 weeks before mating and during 3 weeks of gestation plus 3 weeks of lactation. Controls were supplied drinking water. At birth, part of Cd-exposed dams’ litters was cross-fostered to control dams (CCd group) and their control litters were cross-fostered to Cd-exposed dams (CdC group). This procedure enabled to discern the effects of gestational, lactational and gestational plus lactational Cd exposure until weaning in F₁ offspring. Elements were analyzed by atomic absorption spectrometry; hematological parameters manually; and histopathological changes by light microscopy. Gestational plus lactational exposure in Cd-exposed dams and their offspring increased Cd and decreased Fe levels, increased Zn in dams and decreased Zn and body weights in 11- and 21-day pups. In 21-day weanling pups, decreased red blood cell (RBC) count, hemoglobin and hematocrit values and increased reticulocytes in peripheral blood were also found with concomitant histopathological finding of extramedullary hematopoiesis in the liver. In cross-fostered pups with gestational exposure (CCd pups), Fe in the liver decreased on day 11 and Zn increased in the kidney on day 21 whereas in pups with lactational exposure (CdC pups) Zn in the brain decreased on day 11 and Fe decreased in the liver and brain on day 21. Regardless of exposure cessation at weaning, in offspring with gestational plus lactational exposure (Cd-exposed) body weights, kidney and brain Fe levels and RBC and hemoglobin remained decreased in blood until puberty. Furthermore Zn levels increased in the liver, kidney and brain. It was concluded that gestational plus lactational Cd exposure caused decreases in Fe and Zn levels and hematotoxic effects in F₁ offspring more pronouncedly than exposure during either gestational or lactational period alone and the adverse effects of maternally mediated Cd exposure continued after exposure cessation into adulthood.     

Seasonal and locational effects on serum, milk, liver and kidney chromium, manganese, copper, zinc, and iron concentrations of dairy cows

Chromium (Cr), manganese (Mn), copper (Cu), zinc (Zn), and iron (Fe) concentrations were quantified in serum (n=112), milk (n=112), liver (n=70), and kidney samples (n=67) of dairy cows from an iron-steel processing region (Payas-Iskenderun) and from an area free of industrial pollution (Antakya) in Hatay, located in Southern Turkey. Samples were collected in the summer and winter and element determinations were carried out by inductively coupled plasma-atomic emission spectrometry. The mean concentrations of selected elements in serum were found to be similar in both regions. Milk samples collected from the nonindustrial region in the summer had higher Cr, Mn, and Zn concentrations than the polluted region. The liver Cu and kidney Mn levels of samples taken from the industrial region in winter were higher than samples of the unpolluted region. Copper and Fe concentrations in milk, Cr, Mn, Zn, and Fe levels in the liver, and Cr, Cu, Zn, and Fe levels in kidney samples were not found to be different among the regions in both seasons. Copper concentrations were below the critical level in the 25% of serum and 32% of liver samples analyzed in this study. Fifteen percent of serum samples and most of the liver samples had lower amounts of Zn than other reported studies. Although slight differences were observed between the industrial and nonindustrial regions, industrial activities and seasonal changes had no significant effect on selected element concentrations on cows and their milk.     

Response of liver and heart trace elements in rats to the interaction between dietary zinc and iron

An analysis of the interaction between dietary iron (Fe) and zinc (Zn) was performed by using data from Sprague-Dawley rats in a 5 x 4 fully crossed factorially arranged experiment. The concentrations of 9 trace elements from the liver and 10 from the heart were determined and subjected to diverse statistical analyses and were classified by their response to the interaction between dietary Fe and Zn. The interaction was studied by using analysis of variance (ANOVA), discriminant analysis, and logistic regression to determine the direction of interaction; that is, did dietary Fe affect dietary Zn or did dietary Zn affect dietary Fe? The use of discriminant analysis allowed for using multiple parameters (rather than a single parameter) to determine possible interactions between Fe and Zn. Thus, two main levels of interaction were studied: the separate response of each tissue mineral and the response of some grouped minerals. The responses studied were the effect of dietary Zn on tissue trace element parameters, the effect of dietary Fe on the parameters, the effect of dietary Zn on combined (grouped) parameters, and the effect of dietary Fe on combined parameters. As determined by ANOVA, only three individual trace elements--liver Fe, Cu, and Mo--were significantly affected by the interaction between Fe and Zn. However, a broader interaction between Fe and Zn is revealed when groups of, rather than single, trace elements arestudied. For example, an interaction between dietary Fe and Zn affects the weighted linear combination of heart Ca, Cu, K, Mg, Mn, P, and Zn. This article presents the hypothesis that grouped parameters may be useful as status indicators. The complete dataset can be found at http://www.gfhnrc.ars. usda.gov/fezn.     

Inhibition of iron and copper uptake by iron, copper and zinc

Interactions of micronutrients can affect absorption and bioavailability of other nutrients by a number of mechanisms. In aqueous solutions, and at higher uptake levels, competition between elements with similar chemical characteristics and uptake process can take place. The consequences of these interactions may depend on the relative concentrations of the nutrients. In this work, we measure the effects of increasing concentrations of iron, zinc, and copper on iron and copper uptake in Caco-2 cells. Intracellular Fe or Cu levels were affected by incubating with increased concentrations of metals. However, when the cells already had different intracellular metal concentration, the uptake of Fe or Cu was nor affected. In competition studies, we showed that Cu and Zn inhibited Fe uptake, and while Fe inhibited Cu uptake, Zn did not. When the three metals were given together (1:1:1 ratio), Fe or Cu uptake was inhibited approximately 40%. These results point to a potential risk in the absorption and bioavailability of these minerals by the presence of other minerals in the diet. This aspect must be considered in food supplementation and fortification programs.     

Levels of iron, zinc, and copper in aqueous humor, lens, and serum in nondiabetic and diabetic patients

The purpose of this study was to investigate iron (Fe), zinc (Zn), and copper (Cu) levels of aqueous humor, lens, and serum in nondiabetics and diabetics and to determine the effects of diabetes on Fe, Zn, and Cu contents in the lens. Fe, Zn, and Cu contents of aqueous humor, lens, and serum samples of 19 patients (9 nondiabetic patients with a mean age of 62.3±5.4 yr, and 10 diabetic patients with a mean age of 59.5±5.9 yr) were analyzed by atomic absorption spectrometry using a prospective study design. The lens levels of Cu in diabetic patients were significantly higher compared with nondiabetic patients (p=0.02); however; there was no difference in the other elements (Zn, Fe; p=0.28, p=0.74, respectively). The levels of Fe, Zn, and Cu in the aqueous humor and serum of diabetic patients were not found to be statistically significant when compared to nondiabetics (p=0.46, p=0.11, p=0.18, and p=0.22, p=0.43, p=0.72, respectively). These results demonstrate that increased Cu content of the lens presumably has a greater association with the development of lens opacification in diabetics than Zn and Fe content.     

Effect of dietary Ca and Cd level of pregnant rats on reproduction and on dam and progeny tissue mineral concentrations.

Pregnant Sprague-Dawley rats were used to determine the effects of the addition of 200 ppm of Cd (as CdCl2) to the diet factorially with two levels of dietary Ca (0.07% and 0.96%) on reproductive performance, concentrations of Cd, Cu, Fe, Zn, Ca and Mg in dam liver and kidney and in newborn progeny. High Cd significantly increased liver and kidney Cd, Zn and Ca and decreased liver Fe. High dietary Ca partially protected against accumulation of Cd in liver and kidney but had no effect on concentration of other elements. Number of live or stillborn pups per litter was not significantly affected by diet but high Cd significantly reduced pup birth weight. No grossly abnormal pups were noted. Concentration of Cd in bodies of newborn pups was increased approximately 8.6-fold by high Cd in the diet of dams fed the 0.07% Ca-diet and 3.8-fold by high-Cd in the diet of dams fed the 0.96% Ca diet. Pup, Zn, Cu and Fe contents were significantly decreased and Ca was significantly increased by high-Cd in the maternal diet whereas pup Mg content was unchanged. Maternal Ca intake had no effect on concentration of Zn, Cu, Fe or Ca in newborn pups. The biological importance of the alteration in maternal and fetal tissue concentration of Zn, Cu and Fe by high-Cd maternal diets is unknown.     

Blood levels of copper, iron, zinc, and lead in adults in India and Pakistan and the effect of oral zinc supplementation for six weeks

Deficiency in the intake of trace elements, such as copper (Cu), iron (Fe), selenium (Se), and zinc (Zn), is very common in the general population of most developing countries. A preliminary study in India and Pakistan showing the plasma levels of Zn and Fe indicates that approx 50% of the subjects who participated have low levels of both Fe and Zn, suggesting a marginal deficiency. The low plasma levels of these elements are more pronounced in females. The mean levels of Ze, Cu, and Fe in the plasma of 83 subjects were 0.71 ± 0.11, 0.96 ± 0.10, and 0.80 ± 0.12 mg/L, respectively. The Cu:Zn ratio in the plasma was 1.43 ± 0.16. Three groups of 15 subjects each were given three different levels of oral supplements of Zn (15, 30, and 45 mg of Zn as Zn gluconate) for 6 wk, and blood samples were analyzed during various intervals. Plasma concentration of Zn increased significantly (p < 0.001) in all the groups after 4 wk of supplementation and reached almost normal levels after 6 wk. Along with the increase in Zn, there was a significant decrease(p < 0.001) in plasma Cu levels. There were no changes in the concentration of Fe during the supplementation period. The supplementation was well tolerated by most subjects. The results of this pilot study indicate that Zn supplementation is a practical possibility comparable to that of Fe supplementation in order to prevent marginal Zn deficiency in vulnerable groups in the general population of developing countries.     

In vivo analysis of metal distribution and expression of metal transporters in rice seed during germination process by microarray and X-ray Fluorescence Imaging of Fe, Zn, Mn, and Cu

To investigate the flow of the metal nutrients iron (Fe), zinc (Zn), manganese (Mn), and copper (Cu) during rice seed germination, we performed microarray analysis to examine the expression of genes involved in metal transport. Many kinds of metal transporter genes were strongly expressed and their expression levels changed during rice seed germination. We found that metal transporter genes such as ZIP family has tendency to decrease in their expressions during seed germination. Furthermore, imaging of the distribution of elements (Fe, Mn, Zn, and Cu) was carried out using Synchrotron-based X-ray microfluorescence at the Super Photon ring-8 GeV (SPring-8) facility. The change in the distribution of each element in the seeds following germination was observed by in vivo monitoring. Iron, Mn, Zn, and Cu accumulated in the endosperm and embryos of rice seeds, and their distribution changed during rice seed germination. The change in the patterns of mineral localization during germination was different among the elements observed.     

Interactions between toxic (As, Cd, Hg and Pb) and nutritional essential (Ca, Co, Cr, Cu, Fe, Mn, Mo, Ni, Se, Zn) elements in the tissues of cattle from NW Spain

Since the toxicity of one metal or metalloid can be dramatically modulated by the interaction with other toxic or essential metals, studies addressing the chemical interactions between trace elements are increasingly important. In this study correlations between the main toxic (As, Cd, Hg and Pb) and nutritional essential (Ca, Co, Cr, Cu, Fe, Mn, Mo, Ni, Se, Zn) elements were evaluated in the tissues (liver, kidney and muscle) of 120 cattle from NW Spain, using Spearman rank correlation analysis based on analytical data obtained by ICP-AES. Although accumulation of toxic elements in cattle in this study is very low and trace essential metals are generally within the adequate ranges, there were significant associations between toxic and essential metals. Cd was positively correlated with most of the essential metals in the kidney, and with Ca, Co and Zn in the liver. Pb was significantly correlated with Co and Cu in the liver. A large number of significant associations between essential metals were found in the different tissues, these correlations being very strong between Ca, Cu, Fe, Mn, Mo and Zn in the kidney. Co was moderately correlated with most of the essential metals in the liver. In general, interactions between trace elements in this study were similar to those found in polluted areas or in experimental studies in animals receiving diets containing high levels of toxic metals or inadequate levels of nutritional essential elements. These interactions probably indicate that mineral balance in the body is regulated by important homeostatic mechanisms in which toxic elements compete with the essential metals, even at low levels of metal exposure. The knowledge of these correlations may be essential to understand the kinetic interactions of metals and their implications in the trace metal metabolism.