Showing papers in "Biological Trace Element Research in 1994"

Supplementation with selenium and human immune cell functions. II. Effect on cytotoxic lymphocytes and natural killer cells

Abstract: This study examined the effect of dietary (200 μg/d for 8 wk) supplementation with selenium (as sodium selenite) on the ability of human peripheral blood lymphocytes to respond to stimulation with alloantigen, develop into cytotoxic lymphocytes, and to destroy tumor cells, and on the activity of natural killer cells. The participants in the study were randomized for age, sex, weight, height, and nutritional habits and given selenite or placebo tablets; all participants had a selenium replete status as indicated by their plasma Se levels prior to supplementation. The data indicated that the supplementation regimen resulted in 118% increase in cytotoxic lymphocyte-mediated tumor cytotoxicity and 82.3% increase in natural killer cell activity as compared to baseline values. This apparently was related to the ability of the nutrient to enhance the expression of receptors for the growth regulatory lymphokine interleukin-2, and consequently, the rate of cell proliferation and differentiation into cytotoxic cells. The supplementation regimen did not produce significant changes in the plasma Se levels of the participants. The results indicated that the immunoenhancing effects of selenium in humans require supplementation above the replete levels produced by normal dietary intake.

Supplementation with selenium and human immune cell functions. I. Effect on lymphocyte proliferation and interleukin 2 receptor expression.

Abstract: Selenium (Se) is an essential nutritional factor that was shown by us to alter the expression of the high affinity interleukin 2 receptor (Il2-R) and its subunits, cell proliferation, and clonal expansion of cytotoxic T-lymphocytes in mice. This study shows that dietary supplementation of Se-replete humans with 200 micrograms/d of sodium selenite for 8 wk, or in vitro supplementation with 1 x 10(-7) M Se (as sodium selenite), result in a significant augmentation of the ability of peripheral blood lymphocytes to respond to stimulation with 1 microgram/mL of phytohemagglutinin or alloantigen (mixed lymphocyte reaction) and to express high affinity Il2-R on their surface. There was a clear correlation between supplementation with Se and enhanced 3H-thymidine incorporation into nuclear DNA, preceded by enhanced expression of high affinity Il2-R. Supplementation with Se can apparently modulate T-lymphocyte mediated immune responses in humans that depend on signals generated by the interaction of interleukin 2 with Il2-R.

Serum copper and zinc levels and copper/zinc ratio in patients with breast cancer

Abstract: Serum copper, zinc levels, and the Cu/Zn ratio were evaluated in 31 patients with breast cancer and 35 healthy controls. Copper and zinc were determined by atomic absorbtion spectrophotometry. The mean serum copper level and the mean Cu/Zn ratio in patients with breast cancer were significantly higher than the control group (p < 0.001 and p < 0.001). In addition, the mean serum zinc level in patients with breast cancer was significantly lower than the control group (p < 0.001). Neither serum copper and zinc levels nor the Cu/Zn ratio were of value in discriminating of the disease activity and severity. Interestingly, the Cu/Zn ratio in premenopausal patients was higher than postmenopausal patients (p < 0.05) and this was not related to age. The further combined biological and epidemiological studies are necessary to investigate the roles of copper and zinc in breast cancer.

An Elemental Correlation Study in Cancerous and Normal Breast Tissue with Successive Clinical Stages by Neutron Activation Analysis

Abstract: Influence of trace elements in body metabolism and their physiological importance in various diseases have motivated their accurate and quantitative determination in biological tissues and fluids. Instrumental Neutron Activation Analysis (INAA) using short and long term irradiation has been employed to determine five minor elements (Cl, K, Na, Mg, P) and 15 trace elements (As, Br, Co, Cr, Cs, Cu, Fe, Hg, Mn, Rb, Sb, Se, Sc, Sr, and Zn) in cancerous and normal breast tissue from 30 patients of four clinical stages. Several elements show enhancement in cancerous breast tissue. Selenium shows maximum enhancement of 94.7% followed by K (81.6%), Sc (66.7%), Cu (58.2%) Na (48.5%), P (44.4%), and Zn (39.2%). Some elements, such as Fe, Cr, and Mn, are depressed by 30.8, 30.1, and 12.8%, respectively. These elements compete for binding sites in the cell, change its enzymatic activity and exert direct or indirect action on the carcinogenic process accelerating the growth of tumors. This is further evidenced by histopathological examination of cancerous cells showing poor cytological differentiation. An attempt has been made to correlate trace element concentrations of Se, Cu, Zn, Rb, Br, Hg, As, Co, Fe, Cr, and Mn and the ratios of Se/Zn, K/P, Cu/Zn, Na/K, and Se/Fe with the clinical stages of cancer. Inhibition of enzymatic activity caused by variation in trace element concentrations results in immunological breakdown of the body system.

The influence of color, age, and sex on the content of zinc, copper, nickel, manganese, and lead in human hair.

Abstract: The hair of 132 healthy subjects between 6 and 40 yr old living in the Veneto region in Italy was analyzed by means of HPLC method in order to determine the presence of zinc, copper, nickel, manganese, and lead. The collected samples were subdivided on the basis of age (6–11 and 19–40 yr), and sex and color (black, red, brown, and blond). From the data some evident differences were emphasized. In female hair the content of metals was higher than in male hair independently of color. Blond hair gave the lowest concentration values of the elements studied independently of sex. The maximum amount of the metals was found generally in black hair, followed by red and brown hair. Age seems to have a different influence, with the copper element decreasing appreciably in brown and blond female hair as the age of the subjects increased.

The effect of aging on the mineral status of female mice.

Abstract: To clarify the effect of aging on the mineral status of female mice, mineral concentrations in their tissues were determined. Five 2-mo-old, five 6-mo-old, and five 10-mo-old female B10BR mice were fed a commercial diet. Iron, zinc, copper, calcium, magnesium, sodium, and potassium concentrations in the blood, liver, kidney, heart, brain, lung, and spleen of the mice were determined using a flame atomic absorption spectrophotometer. Iron concentrations in the liver, kidney, heart, brain, and spleen increased with age. Significant differences were detected between mice 2 and 6 mo of age and between mice 2 and 10 mo of age. Zinc concentrations in the heart and lung decreased significantly with age. Zinc concentrations in the heart and lung of 10-mo-old mice were significantly lower than those of 2-mo-old mice. It is noteworthy that the copper concentration in the brain of 10-mo-old mice was markedly higher compared with that of younger mice. Calcium accumulation was apparent in the kidney of mice at 10 mo.

Determination of aluminum levels in the kidney, liver, and brain of mice treated with aluminum hydroxide

Abstract: In the present study, aluminum (Al) accumulation has been examined after aluminum loading in mice. The kidney, liver, and brain aluminum levels for mice that had been treated orally with aluminum hydroxide for 105 d and for the control group were determined using graphite furnace atomic absorption spectrophotometry (GFAAS) following an acid digestion. Matrix modifier consisted of 2% Triton X-100 and 2% Mg (NO3)2. Al loaded mice showed a significant increase in tissue aluminum levels, relative to the control group.

Dietary zinc-methionine enhances mononuclear-phagocytic function in young turkeys

Abstract: The ability of dietary zinc-methionine (Zn-Met) to enhance mononuclear-phagocytic function againstSalmonella arizona andenteritids was investigated in young turkeys. Feed/gain and body wt gain at 21 d of age were not affected by Zn-Met. The addition of 30 or 45 ppm Zn from Zn-Met to a Zn adequate diet significantly increased cutaneous basophil hypersensitivity to phytohemagglutinin-P. The clearance of intravenously administeredS. enteritidis from blood was not affected by 30 ppm of supplemental Zn from Zn-Met. However, 30 ppm Zn from Zn-Met increased the reduction of intravenously administeredS. arizona from spleen. Percentages of myeloid and mononuclear-phagocytic cells before and afterS. enteritidis infection were not affected by supplemental Zn-Met. Turkeys supplemented with Zn-Met showed enhanced in vitro phagocytosis ofS. enteritidis by Sephadex-elicited abdominal exudate cells. The phagocytosis ofS. arizona was unaffected by Zn-Met.

Efficiency of serum copper/zinc ratio for differential diagnosis of patients with and without lung cancer.

Abstract: We examined serum copper (Cu), serum zinc (Zn), and the serum copper/zinc ratio (Cu/Zn) in 162 patients. All of them were seen to have an abnormal shadow in the chest X-ray films, that is, 109 patients with lung cancer (LC) and 53 patients with no lung cancer (NLC). The mean Cu and Cu/Zn in LC patients were significantly higher than those in NLC patients (p < 0.05). In LC patients, Cu and Cu/Zn were higher and Zn was lower in advanced tumors than early ones. There was a significantly clear relation between Cu or Cu/Zn and the tumor (T) stages. When the relative risk (RR) of LC was estimated, it was seen that the higher Cu and Cu/Zn became, the higher RR became. Furthermore, we showed the sensitivity of the receiver operator characteristic of the test (ROC) curve for Cu, Cu/Zn, and carcinoembryonic antigen (CEA) to diagnose LC, as explained in a paragraph of methods. The determinations of Cu, Zn, and Cu/Zn are simple and inexpensive. They also appear to have a great diagnostic value in determining the local invasion of LC and as a screening test in the high-risk patients for LC.

Effects of germanium and silicon on bone mineralization.

Abstract: The chemical properties of Ge are similar to Si. This study investigated whether Ge can substitute for, or is antagonistic to, Si in bone formation. Sixty male weanling Sprague-Dawley rats were randomly assigned to treatment groups of 12 and 6 in a 2 x 4 factorially arranged experiment. The independent variables were, per gram fresh diet, Si (as sodium metasilicate) at 0 or 25 micrograms and Ge (as sodium germanate) at 0, 5, 30, or 60 micrograms. Results confirmed that Ge does not enhance Si deprivation and provided evidence that Ge apparently can replace Si in functions that influence bone composition. When Si was lacking in the diet, calcium and magnesium concentrations of the femur were decreased; this was reversed by feeding either Ge and/or Si. Similar effects were found for zinc, sodium, iron, manganese, and potassium of vertebra. There were some responses to Si deprivation that Ge could not reverse; Ge did not increase femur copper, sodium, or phosphorus or decrease molybdenum of vertebra, effects that were evoked by Si supplementation. Additionally, some findings suggested that 60 micrograms Ge/g diet could be a toxic intake for the rat. On the other hand, some responses induced by Ge indicate that this element may be acting physiologically other than as a substitute for Si. Germanium itself affected bone composition. Germanium supplementation decreased Si and molybdenum in the femur and increased DNA in tibia. Regardless of the amount of Si fed, animals fed 30 micrograms Ge/g diet had increased tibial DNA compared to animals fed 0 or 60 micrograms Ge; however, tibial DNA of animals fed 30 micrograms Ge was not statistically different from those animals fed 5 micrograms Ge. Thus, Ge may be of nutritional importance.

The accumulation of the rare earth elements and of scandium in successive needle age classes of Norway spruce.

Abstract: The endogenous concentrations of Sc, La, Ce, Sm, Eu, Tb, Yb, and Lu were determined by neutron activation analysis in up to five successive needle age classes of Norway spruce (Picea abies). Trees from nine sites over different bedrocks were sampled individually. Concentration values found are generally much lower than those reported in the literature. This is attributed to the careful removal of any aerosols or soil particles from the needle surface prior to analysis. The concentration of each element increases linearly with the needle age class, i.e., the accumulation can be characterized by just one parameter, the yearly increment. This pattern is followed at small as well as at large concentrations. The accumulation behavior of the investigated elements is identical to that of Si. The relative concentrations of the rare earth elements (REE) in the needles are similar to those in the earth crust. There are significant correlations between the individual REE and between Sc and La.

Vanadium compounds. Their action on alkaline phosphatase activity.

Abstract: The direct effect of different vanadium compounds upon alkaline phosphatase (ALP) activity was investigated. Vanadate and vanadyl inhibited both the soluble and particulate ALP activity from UMR.106 cells and from bovine intestinal ALP. We have also shown the inhibition of ALP activity in the soluble fraction of osteoblasts by peroxo and hydroperoxo vanadium compounds. ALP activity in the particulate fraction was not inhibited by these species; nor was the bovine intestinal ALP. Using inhibitors of Tyr-phosphatase (PTPases), the soluble ALP was partially characterized as a PTPase. The major activity in the particulate fraction represents the bone-specific ALP-activity. This study demonstrates that different forms of vanadium are direct inhibitors of ALP activity. This effect is dependent on the enzymatic activity investigated and on the origin of the ALP.

Refrigeration of blood samples prior to separation is essential for the accurate determination of plasma or serum zinc concentrations.

Abstract: An evaluation of refrigeration (7 degrees C) to prevent falsely high plasma or serum zinc concentrations owing to elapsed time between blood collection and centrifugation was performed. At room temperature (23 degrees C), both plasma and serum zinc concentrations increased significantly, if blood samples were stored uncentrifuged. Plasma zinc concentrations increased 6.3% at 1 h and 40.7% at 24 h, whereas serum zinc concentrations increased only 0.9% at 1 h and 12.5% at 24 h at room temperature. When blood samples were stored uncentrifuged in the refrigerator for up to 24 h, there were no significant increases in zinc concentrations in either plasma or serum. These findings suggest that plasma or serum separation should be performed immediately after blood drawing to obtain accurate zinc concentrations, and if this is not feasible, the samples should be immediately refrigerated and separation performed within eight hours.

Studies on lipid oxidation in fish phospholipid liposomes.

Abstract: Fish phospholipid liposomes were prepared and used as an artificial membrane system to study factors influencing lipid oxidation. The extent of lipid oxidation was indexed by measuring the amount of thiobarbituric acid reactive substances (TBARS) produced. Fe2+, Fe3+, and Cu2+ were potent prooxidants in catalysing lipid oxidation. These metal ions induced lipid oxidation in a dose dependent manner. However, Zn2+, Ni2+, and Mn2+ did not significantly (p > 0.05) affect lipid oxidation at all the concentrations (1, 10, or 100 microM) studied. Morin, luteolin (flavonoids), butein (chalcone), tannic acid, ellagic acid (polyphenols), butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT) (synthetic antioxidants) were potent antioxidants (producing < 50% TBARS compared to control) of Fe(2+)-catalyzed lipid oxidation. Morin, luteolin, and butein possess two hydroxyl substituents, a C4 ketone structure and a 2-3 double bond, all of which contributed to their antioxidative potential. Fe2+ caused some losses of polyunsaturated fatty acids (PUFA), whereas tannic acid protected the oxidation of several of the PUFA including C 16:1 (Palmitoleic acid), C 18:3 (Linolenic acid), C 20:4 (Arachidonic acid), C 20:5 (Eicosapentaenoic acid), and C 22:6 (Docosahexaenoic acid).

Trace-elements status in camels. A review.

Abstract: Data relating to trace-elements status in camels is scarce, from both a clinical and biochemical point of view. Clinical deficiency or toxicity has rarely been described in this species. However, there is a some evidence that camels are sensitive to trace element disorders in the same way as other ruminants. For example, copper deficiency in camels has been reported in East Africa. Normal plasma level is comparable to cattle (70-120 mg/100 mL). Camels appear to maintain zinc levels at a lower value than other domestic ruminants (< 60 micrograms/100 mL). Iron metabolism is more active in the liver than in the spleen. Data concerning manganese levels are possibly unreliable. Some cases of selenium deficiency (white muscle disease) have been reported. No data are available for cobalt status in camels. Finally, camels appear to be more sensitive to iodine deficiency than the other domestic ruminants.

Effects of nutritional lithium supplementation on mood. A placebo-controlled study with former drug users.

Abstract: A total of 24 subjects, 16 males and 8 females, average age 29.4 +/- 6.5 y, were randomly divided into two groups. Group A received 400 micrograms/d of lithium orally, in tablets composed of a naturally lithium-rich brewer's yeast, for 4 wk. Group B was given normal, lithium-free brewer's yeast as a placebo. All the subjects of the study were former drug users (mostly heroin and crystal methamphetamine). Some of the subjects were violent offenders or had a history of domestic violence. The subjects completed weekly self-administered mood test questionnaires, which contained 29 items covering parameters measuring mental and physical activity, ability to think and work, mood, and emotionality. In the lithium group, the total mood test scores increased steadily and significantly during the period of supplementation. The 29 items were furthermore placed into three subcategories reflecting happiness, friendliness, and energy, as well as their negative counterparts. In Group A, the scores increased consistently for all subcategories until wk 4 and remained essentially the same in wk 5. In Group B, the combined mood test scores showed no consistent changes during the same period. The only positive change in some members of Group B occurred during wk 1 and was attributed to a placebo effect. In Group B, the placebo effect was noticeable for the subcategories of energy and friendliness; the happiness scores declined during the entire period of observation. Based on these results and the analysis of voluntary written comments of study participants, it is concluded that lithium at the dosages chosen had a mood-improving and -stabilizing effect.

Impact of lead pollution on the status of other trace metals in blood and alterations in hepatic functions.

Abstract: Lead pollution and its impact on the status of four other trace elements—Fe, Zn, Br, and Rb—have been studied in the whole blood samples of different population groups employing energy dispersive X-ray fluorescence technique. These population groups included normal, automobile workers and lead battery manufacturers. The maximum increase in the concentration of trace elements in the blood samples of automobile workers and battery manufacturers was observed for Pb, when compared with normal Pb-B levels. The effect of lead pollution had significantly reduced Zn levels in automobile workers. Fe-B levels in automobile workers had been found to be reduced significantly as compared to control, whereas in battery workers the reduction was not significant. The concentration of Br was greatly enhanced in the blood samples of automobile workers, whereas Rb-B levels were significantly higher in both the automobile and battery workers. Oral administration of lead acetate (100 mg/kg body wt) to experimental rats significantly decreased the activities of hepatic transaminases after 3 and 4 mo of treatment, whereas the activity of hepatic alkaline phosphatase decreased significantly after 4 mo of treatment. It is concluded from this study that higher Pb-B levels greatly influence the levels of other trace elements in human blood samples and also the activities of hepatic transaminases as well as alkaline phosphatase in experimental rats.

Concentrations of cadmium, lead, selenium, and zinc in human blood and seminal plasma.

Abstract: The concentrations of cadmium, lead, selenium, and zinc in blood and seminal plasma were determined in 76 Singapore males. Except for zinc, the concentrations were generally higher in blood than in seminal plasma (cadmium, 1.31 μg/L vs 0.61 μg/L; lead, 82.6 μg/L vs 12.4 μg/L, and selenium, 163.6 μg/L vs 71.5 μg/L). The mean concentration of zinc in seminal plasma was more than 30 times higher than in blood (202 mg/L vs 6.2 mg/L). Significant positive correlations were found between the concentrations in blood and seminal plasma for the two essential trace elements: selenium (r=0.45,p<0.001) and zinc (r=0.25,p<0.05). However, no relationships were found between the concentrations in blood and seminal plasma for two toxic metals (cadmium and lead). Significant inverse correlations were observed between Cd and Zn (r=−0.40,p<0.01), and Pb and Se (r=−0.32,p<0.05) in blood, whereas significant positive correlations were noted between Cd and Se (r=0.45,p<0.01), Cd and Zn (r=0.35,p<0.05), and Se and Zn (r=0.57,p<0.001) in seminal plasma. The physiological significance of these relationships are also discussed in this paper.

Interaction of trace elements in a longitudinal study of human milk from full-term and preterm mothers

Abstract: Concentrations of 8 trace elements (Fe, Cu, Zn, Se, Br, Pb, Rb, and Sr) at different lactation time were measured by the PIXE multi-elemental technique. Time dependence and interelement correlations were studied. A total of 200 milk samples from 32 lactating mothers were supplied from 2 to 120 d after delivery of 26 full-term and 6 preterm infants. All elements showed a lognormal frequency-distribution. The Fe, Cu, Zn, and Se contents in preterm milk were found to be somewhat different with respect to full-term milk. Cu, Zn, Se, Br, Pb, and Rb concentrations declined with lactation time, both in pre- and full-term samples. Sr and Fe contents did not show any change with time. Detailed analysis of data by partial correlation and multiple regression methods was performed. No substantial differences between preterm and full-term samples were found in the results of partial correlation analysis. Cu and Zn were found to be correlated with lactation time, whereas the measured time dependence for the other elements has to be attributed to the effect of the existing interelement correlation. All the measured elements appeared to be correlated with at least one other element. In particular, Se was inversely correlated with Zn and directly with Cu. The zinc and copper contents in milk can therefore depend on the variation in the mother selenium intake.

Elemental Composition of Head Hair and Fingernails of Some Nigerian Subjects

Abstract: In this article, we present the elemental concentrations determined by INAA for 30 elements measured in some or all head hair samples of 100 Nigerian subjects and 20 elements in the fingernails of some of the same subjects. Measurements of the skewness of the distribution of each element in both tissues confirm previous reports that many tend toward a log-normal distribution. Thus, their concentrations in the tissues may not be under any homeostatic control. The ranges of elemental concentrations together with the medians, and the arithmetic and geometric means, with their respective standard deviations are presented and compared with literature values for other populations. Correlations between elements detected in hair are also sought.

The role of the pancreas in the regulation of zinc status.

Abstract: A low Zn diet resulted in subacute Zn deficiency in young rats. Thirty minutes after the intubation of a trace 65-Zn we determined the total tissue Zn activity in plasma, erythrocytes, liver, pancreas, bone, muscle, and proximal jejunum. Assuming the body behaved like a closed multicompartmental system in steady state, we estimated the initial Zn exchange between plasma, and the erythrocytes or these tissues. In comparison with control animals the exchanges between plasma and erythrocytes or pancreas increased threefold during subacute Zn deficiency. In the pancreas the ratio also reversed from 1.0. This confirmed earlier observations that the specific activity (kBq 65-Zn/mol Zn) increased mostly in the pancreas. By increased net Zn uptake during subacute deficiency, the pancreas Zn content remained constant in chronic Zn deficiency. We discussed the regulation of the Zn status by the pancreas. We hypothesize that the exocrine pancreas modulates Zn absorption by an exocrine ligand that enhances absorption in the jejunum during subacute deficiency: Unsaturated with Zn it binds dietary intraluminal Zn and increases the Zn absorption. The literature provides evidence in confirmation. This hypothesis explains also conflicting data on the inherited Zn malabsorption syndrome Acrodermatitis Enteropathica.

Sodium selenite therapy and thyroid-hormone status in cystic fibrosis and congenital hypothyroidism.

Abstract: The effectiveness of a peroral sodium selenite therapy (115 μg Se/m2 BSA/d) administered to cystic fibrosis patients (n=32) could after three months be identified in a significant serum selenium increase (0.69→0.96 μmol/L), a significant malondialdehyde decrease (2.72→1.64 μmol/L), as well as in a significant serum vitamin E increase (4.31→5.72 μg/mL) Parallel to that, a serum T3 increase as well as a highly significant decrease in the serum T4/T3-ratio were found, too, which point to improved peripheral T4→T3 conversion during selenium medication. Type-I-iodothyronine-5′-deiodinase has recently been identified as a specific selenoenzyme.

Trace elements nutritional status. Use of hair as a diagnostic tool.

Abstract: In this study, hair levels of Cu and Zn were determined in healthy male and female individuals (n=192) ages 3.6–14.5 yr and the correlations with Cu and Zn daily intakes were examined. Determinations of Cu and Zn concentrations were performed by way of atomic absorption spectrometry and X-ray fluorescence. Nutritional data were collected with the aid of an individual questionnaire. Statistical analysis revealed no effect of age and sex either on Cu concentrations in hair or on Cu daily intakes. Zn concentrations were significantly higher in hair of both pubescent males and females compared with prepubescent individuals. There was no influence of age on Zn daily intake in males, however, whereas pubescent girls had a lower intake than males. Correlation coefficients between Cu concentrations in hair and daily nutritional intakes calculated for males and females werer=0.1694 andr=0.1677, respectively; those for Zn werer=−0.2223 (p<0.05) in males andr=−0.2787 (p<0.01) in females. These data confirm that the analysis of Zn in hair represents an addition to conventional materials in the assessment of the nutritional status of groups of individuals.

Manganese status, gut endogenous losses of manganese, and antioxidant enzyme activity in rats fed varying levels of manganese and fat

Abstract: We hypothesized that manganese deficient animals fed high vs moderate levels of polyunsaturated fat would either manifest evidence of increased oxidative stress or would experience compensatory changes in antioxidant enzymes and/or shifts in manganese utilization that result in decreased endogenous gut manganese losses. Rats (females in Study 1, males in Study 2,n = 8/treatment) were fed diets that contained 5 or 20% corn oil by weight and either 0.01 or 1.5 μmol manganese/g diet. In study 2,54Mn complexed to albumin was injected into the portal vein to assess gut endogenous losses of manganese. The manganese deficient rats: 1. Had 30–50% lower liver, tibia, kidney, spleen, and pancreas manganese concentrations than manganese adequate rats; 2. Conserved manganese through ≈70-fold reductions in endogenous fecal losses of manganese; 3. Had lower heart manganese superoxide dismutase (MnSOD) activity; and 4. Experienced only two minor compensatory changes in the activity of copper-zinc superoxide dismutase (CuZnSOD) and catalase.

Factors affecting the selenium intake of people in Transbaikalian Russia.

Abstract: The selenium concentration in foods grown and consumed and in plasma, red blood cells, and toenails of people living in the district of Chita in the transbaikalian part of Russia were studied in August 1991. Preliminary results from the area have suggested low selenium intakes and the possible occurrence of cardiomyopathy (Keshan disease) in the population. A low selenium concentration in foods grown locally was found: mean selenium concentration in wheat grains was 1, 5, and 28 μg/kg, respectively, in three villages studied, that of oats was beween 3–6 μg/kg, and of cow's milk 10–27 μg/kg dry matter. The selenium concentration of bread was considerably higher, between 87–337 μg/kg dry wt, presumably because wheat imported from the US had been used for baking. Occasional samples of pork, beef, and mutton contained between 32–318 μg selenium/kg dry wt. Low selenium concentrations were observed in samples of soil and river water. The mean plasma selenium concentration of 52 persons was 1.02 μmol/L, including 33 children and 19 adult subjects. The selenium concentrations in red blood cells and toenails were 1.95 μmol/L and 0.61 mg/kg, respectively. No symptoms of heart disease caused by selenium deficiency were observed. It is concluded that the selenium status of people was fairly good thanks to the contribution to dietary intake of imported wheat with a high selenium content. As the selenium concentration was very low in foods grown in the area, the selenium intake of the population will be reduced to a very low level if only locally produced foods are consumed.

Sum and Mean

Abstract: Two computer programs in use for over a decade in the Nuclear Methods Group at NIST illustrate the utility of standard software: programs widely available and widely used, in which (ideally) welltested public algorithms produce results that are well understood, and thereby capable of comparison, within the community of users.Sum interactively computes the position, net area, and uncertainty of the area of spectral peaks, and can give better results than automatic peak search programs when peaks are very small, very large, or unusually shaped.Mean combines unequal measurements of a single quantity, tests for consistency, and obtains the weighted mean and six measures of its uncertainty.

Heavy metal intracellular balance and relationship with metallothionein induction in the gills of carp. After contamination by Ag, Cd, and Hg following pretreatment with Zn or not.

Abstract: Determination of metal levels (Cu, Zn, Cd, Ag, Hg) in soluble and insoluble fractions of gill homogenates has been performed after 7 d exposure of carp (Cyprinus carpio) to moderate concentrations of Cd, Ag, and Hg in water. Metallothionein levels have been quantified by polarographic method before and after contamination and a subsequent decontamination phase (7 d). The influence of pretreatment by zinc (7 d) has also been evaluated. Metallothionein level variations have been interpreted as having regard to interrelated flows of metal between subcellular fractions. Special interest has been focused on heat-stable compound (HSC)-bound heavy metal flows within the cytosol, taking in account that MT is the major component of these ligands. Our data showed differences between the ability of metals to bind cytosolic ligands and HSCs, and their respective potency for MT induction in gill. Regardless of pretreatment, mercury gave the highest increase of gill MT, and after the decontamination MT level remained high compared to control. Cadmium and silver gave similar increases, but a significant difference with control appeared only after the decontamination step with silver, whereas 1 week of contamination was enough for cadmium. Our experimental conditions gave the following order of potency for MT induction in gill: Hg≫Cd>Ag>Zn.

Does dietary arsenic and mercury affect cutaneous bleeding time and blood lipids in humans

Abstract: Fish species may contain considerable amounts of trace elements, such as selenium (Se), arsenic (As), and mercury (Hg). The present study investigated the relationships between dietary intake of these elements and cutaneous bleeding time and blood lipids in 32 healthy volunteers. For 6 wk, one group (n=11) consumed approx 250 g Se-rich fish daily, providing them with an average Se intake of 115±31 μg Se/d, Hg intake of 18±8 μg/d, and As intake of 806±405 μg/d, all values analyzed in 4-d duplicate food collections. To study the effect of Se alone, one group (n=11) included Se-rich bread in their normal diet, giving them a Se intake (135±25 μg/d) that was comparable to the fish group. A control group (n=10) ate their normal diet, providing 77±25 gmg Se/d, 3.1±2.5 μg Hg/d, and 101±33 μg As/d. The dietary As load strongly correlated both with bleeding times and changes in bleeding times (r=0.48,p<0.01 andr=0.54,p<0.002, respectively). Dietary Hg showed a positive correlation with LDL-cholesterol (r=0.55,p<0.01), whereas dietary Hg in the fish group showed a strong negative relationship with HDL-cholesterol (r=−0.76,p<0.01). Selenium seemed to have only a modest effect on bleeding time. Our results suggest that mercury and arsenic from fish may be factors contributing to or modifying some of the known effects of fish ingestion.

Application of Nuclear Analytical Methods in the Investigation and Identification of New Selenoproteins

Abstract: Nuclear methods have been applied in the investigation of selenium-containing proteins in rat tissues. Selenium was determined in tissues, cells, and cellular compartments by instrumental neutron activation analysis via 77mSe or 75Se. For tracer studies, the selenium compounds were labeled in vivo by administering 75Se with a high specific activity to rats. Quantitative determination of very small amounts of the element in protein fractions was achieved by measurement of the tracer after replenishment of selenium-depleted animals with the labeled element. The application of the nuclear methods in the detection, characterization, and identification of new selenium-containing proteins is shown with the help of some examples.

The longitudinal distribution of cadmium, zinc, copper, iron, and metallothionein in the small-intestinal mucosa of rats after administration of cadmium chloride.

Abstract: Different routes of Cd intake may influence the intestinal distribution of Cd, metallothionein (MT), and trace metals differently. Therefore, we compared the effects of parenteral and enteral administration of Cd on the distribution of trace metals and MT along the small intestine. In a first experiment three groups of rats were employed: a control, one receiving CdCl2 within the drinking water, and another receiving sc injections of CdCl2. In a second experiment, rats were fed three different diets with either 0, 0.3, or 1 mmol CdCl2/kg for one and two weeks to study the time- and dose-dependent effects of orally administered Cd. Metal concentrations (Cd, Zn, Cu, Fe) were measured by atomic emission spectrometry and MT was determined by radioimmunoassay. Intestinal MT levels did not show proximodistal gradients in controls or after sc administration of Cd, but orally administered Cd increased mucosal MT levels longitudinally from the duodenum to the ileum. Cd levels paralleled those of MT. Compared with the metal concentrations in the controls, sc administration of Cd did not change intestinal Zn, Cu, and Fe levels. Oral administration of Cd, however, increased Cu and decreased Fe levels in the intestinal mucosa significantly. The second experiment revealed that only high dietary concentrations of Cd increase intestinal Cd and MT levels longitudinally toward the distal parts, whereas at lower dietary concentration the longitudinal distribution was reversed. This shows that different routes and doses of Cd intake lead to a different trace metal and MT distribution and emphasizes the role of dietary Cd in the local induction of small-intestinal MT.