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PubMedDate not supplied

Mineral status in selenium-deficient rats compared to selenium-sufficient rats fed vitamin-free casein-based or torula yeast-based diet.

To clarify the mineral status in selenium (Se)-deficient rats fed a vitamin-free casein (VFC)-based or torula yeast (TY)-based diet, 24 weanling male Wistar rats were divided into 4 groups fed diets using VFC or TY as the protein source and containing Se at sufficient (0.5 microgram/g, +Se) or deficient (0.019 microgram/g for VFC-based and < 0.005 microgram/g for TY-based diets, -Se) level for 8 wk. TY supplied a larger amount of extra minerals (Na, K, Ca, Mg, Fe, Mn, Zn, and Cu) except Se than VFC. Se concentration and glutathione peroxidase activity were significantly lower in TY-fed rats than in VFC-fed rats, as well as in -Se rats compared to +Se rats. Compared to +Se rats, Fe concentration was higher in liver and muscle of -Se rats fed the VFC-based diet and in plasma, heart, liver, and tibia of -Se rats fed the TY-based diet. Compared to +Se rats, decreases of Mn concentration appeared in plasma, heart, and tibia of VFC-fed -Se rats and in brain, heart, liver and tibia of TY-fed -Se rats. There was also a little imbalance in Ca, Mg, Na, K, and Cu caused by Se deficiency. The results indicated that Se deficiency induced the mineral imbalance in rats, especially an increase in Fe and decrease in Mn, which was more severe in TY-fed rats than VFC-fed rats. However, TY cannot be used as a model for both Se and other mineral deficiency because of the extra minerals except Se found in TY. Instead, VFC can be employed, which contains fewer minerals except Se than TY and also can produce a severe degree of Se deficiency.

Animals↗
PubMed1993

Selenium depletion in patients on home parenteral nutrition. The effect of selenium supplementation.

Severe selenium (Se) depletion was found in nine patients receiving long-term home parenteral nutrition because of short bowel syndrome. Plasma Se ranged from 0-0.51 (median 0.21 mumol/L), and erythrocyte Se ranged from 0.7-2.6 (median 1.8 mumol/gHgb), which was significantly lower than in the controls. Glutathione peroxidase (GSHPx) in plasma and erythrocytes was also decreased. After bolus injections with 200 micrograms Se/d in the form of sodium selenite for 4 mo, followed by 100 micrograms/d for 8 mo, plasma Se increased to values slightly but significantly higher than in the controls. Erythrocyte Se reached normal levels in most of the patients after 4 mo substitution, but it remained lower than in the controls. Following Se supplementation, plasma and erythrocyte GSHPx did not differ between patients and controls. These data suggest that all patients receiving long-term parenteral nutrition because of short bowel syndrome should receive at least 100 micrograms sodium selenite/d when given as bolus injections to avoid Se depletion.

Adult↗
PubMedDate not supplied

Effect of selenium in soluble glass bolus on selenium content of milk and blood of goats.

Soluble glass bolus (SGB) with selenium (Se) was administered intraruminally to Se-deficient Philippine does to determine its effect on milk Se and to correlate the Se contents of does' milk and blood of does and kids. Five months after the Se administration, the does in the treated group (n = 14) had higher (p < 0.01) Se content in their blood (62.2 vs 25.7 micrograms/L) and milk (5.1 vs 2.5 micrograms/L) than does in control group (n = 13). Consequently, the blood Se of the kids (n = 14) from the treated does was higher (p < 0.05) than those kids (n = 13) in the control group (28.0 vs 5.1 micrograms/L). Blood and milk Se of does and blood Se of their kids correlated (p < 0.01) with each other. The increased Se level of does' milk because of Se supplementation was not regarded as a health hazard to humans.

Animal Feed↗
PubMed1996

Effect of supplementation with selenium on whole blood glutathione peroxidase activities and on plasma and tissue selenium concentrations in lambs.

In recent years the selenium (Se) intake of the human population of the UK has shown a marked decline from 60 micrograms/d in 1978 to around 30 micrograms/d in 1990 owing largely to a significant reduction in the importation of North American wheat for bread-making flour. Other countries (Finland, for example) in similar situations have instituted fertilization programs in order to raise cereal Se concentrations and thus boost dietary intakes. An alternative approach would be to increase the Se concentration of carcass meat by supplementation of meat animals for a limited period prior to slaughter. A trial was set up with store lambs to evaluate this approach. Sixteen Scottish Blackface lambs were stratified according to live weight and then randomly allocated to one of four treatments: unsupplemented, or 3.5, 7, or 10.5 mg Se/head/wk. After 14 wk, the lambs were sacrificed and samples of shoulder and thigh muscle, liver, and kidney were obtained for analysis. All three treatments effected an increase in whole blood glutathione peroxidase (GSH-Px) and plasma Se concentrations over controls. Shoulder, thigh, and liver Se exhibited a dose-response relationship to treatment, but kidney Se concentrations were unaffected by treatment. Muscle and some organ meat Se concentrations can therefore be increased by supplementation and could contribute to increased human dietary intakes of the element.

Animal Feed↗
PubMed1996

In vitro and in vivo effects of selenium and selenium with vitamin E on platelet functions in diabetic rats relationship to platelet sorbitol and fatty acid distribution.

In vitro 30 min of incubation with selenomethionine (Sm) + vitamin E multiplied by about five platelet selenium (Se) decreased significantly platelet thrombin and ADP-induced aggregation decrease. Four groups of streptozotocin-induced diabetic rats were fed with a supplemented purified diet with an Se-rich yeast (Selenion): DSel, Sm: DSm, Sm alpha-tocopherol: DSmE or unsupplemented diet: D. After 24 wk of supplementation, only a decrease in thrombin-induced aggregation in group DSel compared to DSm and DSmE and D was observed. However, after 24 wk of diet compared to 14 wk, in group D and DSm, a significant increase in thrombin-induced aggregation occurred (p < 0.0001), whereas a significant decrease in groups DSel and DSmE (p < 0.0001, p < 0.03) was noted. After 21 wk of diet, in DSmE, platelet adhesion to fibronectin was significantly decreased compared to group D (p < 0.05). These changes in DSmE were associated with a significant decrease in platelet sorbitol (p < 0.02) and a very significant increase in platelet Se (p < 0.0005). Sm associated with vitamin E would appear more efficient to prevent oxidative damage of diabetic platelet membrane and thus to modulate its hyperactivity.

Adenosine Diphosphate↗
PubMed1996

Selenium, zinc, and thyroid hormones in healthy subjects: low T3/T4 ratio in the elderly is related to impaired selenium status.

Iodothyronine 5' deiodinase, which is mainly responsible for peripheral T3 production, has recently been demonstrated to be a selenium (Se)-containing enzyme. The structure of nuclear thyroid hormone receptors contains Zinc (Zn) ions, crucial for the functional properties of the protein. In the elderly, reduced peripheral conversion of T4 to T3 with a lower T3/T4 ratio and overt hypothyroidism are frequently observed. We measured serum Se and RBC GSH-Px (as indices of Se status), circulating and RBC Zinc (as indices of Zn status), thyroid hormones and TSH in 109 healthy euthyroid subjects (52 women, 57 men), carefully selected to avoid abnormally low thyroid hormone levels induced by acute or chronic diseases or calorie restriction. The subjects were subdivided into three age groups. To avoid under- or malnutrition conditions, dietary records were obtained for a sample of 24 subjects, randomly selected and representative of the whole population for age and sex. Low T3/T4 ratios and reduced Se and RBC GSH-Px activity were observed only in the older group. A highly significant linear correlation between the T3/T4 ratio and indices of Se status was observed in the older group of subjects (r = 0.54; p < 0.002, for Se; r = 0.50; p < 0.002, for RBC GSH-Px). Indices of Zn status did not correlate with thyroid hormones, but RBC Zn was decreased in older as compared with younger subjects. We concluded that reduced peripheral T4 conversion is related to impaired Se status in the elderly.

Adult↗
PubMed1996

Toxic levels of selenium in enzymes and selenium uptake in tissues of a marine fish.

Acute toxicity of selenium as selenite in Zosterisessor ophiocephalus by ip injection was studied. The 50% lethal dose and 50% lethal time were measured to be 0.29 ppm and 96 h, respectively. Se concentrations in liver, gill, skin and muscle, and Cyt. P450 level, Se-GPx, and Total GPx enzyme activities in liver were also assessed at different doses and times after injection. Starting at 0.3 ppm injected dose, enzyme activities and Se concentration in tissues, but not in muscle, showed significant differences from the control group. A threshold behavior was inferred. Normal conditions of enzyme activities and Se concentration in tissues were restored about 1 wk after injection. Biological elimination half-lives were about 2 d for liver and gill, and 5 d for skin.

Animals↗
PubMedDate not supplied

Bioavailability of selenium from veal, chicken, beef, pork, lamb, flounder, tuna, selenomethionine, and sodium selenite assessed in selenium-deficient rats.

The bioavailability of selenium (Se) from veal, chicken, beef, pork, lamb, flounder, tuna, selenomethionine (SeMet), and sodium selenite was assessed in Se-deficient Fischer-344 rats. Se as veal, chicken, beef, pork, lamb, flounder, tuna, SeMet, and sodium selenite was added to torula yeast (TY) basal diets to comprise Se-inadequate (0.05 mg Se/kg) diets. Se as sodium selenite was added to a TY basal diet to comprise a Se-adequate (0.10 mg Se/kg), Se-control diet. The experimental diets were fed to weanling Fischer-344 rats that had been subjected to dietary Se depletion for 6 wk. After 9 wk of the dietary Se repletion, relative activity of liver glutathione peroxidase (GSHPx) from the different dietary groups compared with control rats (100%) was: flounder 106%, tuna 101%, pork 86%, sodium selenite 81%, SeMet 80%, beef 80%, chicken 77%, veal 77%, and lamb 58%. Se from flounder was the most efficient at restoring Se concentrations in the liver and skeletal muscle. Se from sodium selenite, SeMet, beef, veal, chicken, pork, lamb, and tuna was not dietarily sufficient to restore liver and muscle Se after 9 wk of recovery following a 6-wk period of Se depletion.

Animals↗
PubMed2005

Current mass spectrometry strategies for selenium speciation in dietary sources of high-selenium.

This document reviews the most relevant mass spectrometry approaches to selenium (Se) speciation in high-Se food supplements in terms of qualitative and quantitative Se speciation and Se-containing species identification, with special reference to high-Se yeast, garlic, onions and Brazil nuts. Important topics such as complexity of Se speciation in these materials and the importance of combining Se-specific detection and molecule-specific determination of the particular species of this element in parallel with chromatography, to understand their nutritional role and cancer preventive properties are critically discussed throughout. The versatility and potential of mass spectrometric detection in this field are clearly demonstrated. Although great advances have been achieved, further developments are required, especially if "speciated"certified reference materials (CRMs) are to be produced for validation of measurements of target Se-containing species in Se-food supplements.

Animals↗
PubMed2000

Effects of water stress on selenium accumulation in tall fescue (Festuca arundinacea Schreb) from a selenium-contaminated soil.

A greenhouse experiment was conducted evaluating the effects of water stress on uptake and accumulation of selenium (Se) as well as on uptake of calcium (Ca), potassium (K), and magnesium (Mg) in tall fescue (Festuca arundinacea Schreb). Also, this study has documented changes in soil Se inventory of Se-contaminated field soil. The findings of this experiment suggest that low soil moisture and plant water stress had a positive effect on plant tissue Se concentration. However, the negative effect of water stress on plant growth superimposed the increase of plant tissue Se concentration. Therefore, Se accumulation and soil Se removal by tall fescue became largely dependent on plant dry weight production. Strategies utilizing for remediation of Se-contaminated soils should maximizing the growth rates of tall fescue by maintaining soil moisture levels above water-stress conditions (greater than -1.0 MPa). The results of this study also suggest that the relative sensitivity of net uptake of Se and the three macronutrients to reduced soil moisture is: Ca uptake < Se uptake < Mg uptake < K uptake.

Calcium↗
PubMed2006

Mechanism for proliferation inhibition by various selenium compounds and selenium-enriched broccoli extract in rat glial cells.

The objective of this study was to investigate the differential effects of various selenium (Se) compounds and Se-enriched broccoli extracts on cell proliferation and the possible mechanism responsible for the Se-induced growth inhibition. C6 rat glial cells were incubated with graded concentrations up to 1000 nM of selenite, selenate, selenomethionine (SeM), Se-methyl-selenocysteine (SeMCys), high-Se broccoli (H-SeB) extract or low-Se broccoli (L-SeB) extract for 24 and 48 h. MTT results indicated that all Se sources and levels examined inhibited C6 cell proliferation at 48 h. The results from cell cycle progression and apoptosis analysis indicated that SeM, SeMCys, H-SeB or L-SeB treatments at the concentration of 1000 nM reduced the cell population in G(0)/G(1) phase, but induced G(2)/M phase arrest and increased apoptosis and secondary necrosis in C6 cells at 24 h. The populations of apoptotic cells and secondary necrotic cells were increased by all Se sources examined. The COMET assay indicated that there was no significant DNA single-strand break found for all Se treatments in C6 cells for 48 h. In addition, the Se-induced proliferation inhibition may involve a hydrogen peroxide (H(2)O(2))-dependent mechanism with elevated cellular glutathione peroxidase (cGPX) activity. Both H-SeB and L-SeB inhibited C6 cell proliferation but H-SeB was less inhibitory than L-SeB. The proliferation inhibition by H-SeB in C6 cells is apparently related to the increased H(2)O(2) with the elevated cGPX activity, but the inhibition by L-SeB was H(2)O(2)-independent without change in cGPX activity.

Animals↗
PubMedDate not supplied

Selenium and experimental allergic encephalomyelitis. The effects of different levels of dietary selenium on clinico-pathological findings.

There are reports in which multiple sclerosis (MS) seems to be associated with abnormalities in selenium (Se) metabolism and erythrocyte glutathione-peroxidase (GSH-px) activity. Ordinary experimental allergic encephalomyelitis (EAE), which reflects some features of human MS, was induced in guinea pigs maintained with high, low and normal levels of Se in the diet. Evidence was obtained to indicate the following results: (i) a direct correlation between dietary Se levels and whole blood Se levels. (ii) Erythrocyte GSH-px activity was not found to be correlated with the blood Se content. (iii) The animals fed with low or normal levels of Se showed the same survival rates and developed EAE in a similar way and percentage. (iv) The animals fed with high non-toxic levels of Se showed a high incidence of death and some developed EAE with a subacute course, when compared with the other experimental groups. The results are discussed on the basis of findings in the literature.

Animals↗
PubMed1991

Selenium in human milk and dietary selenium intake by Greeks.

Fluorimetric determination of selenium in colostrum, transitional and mature human milk gave the following concentrations (mean and standard deviation): 41 +/- 16, 23 +/- 6 and 17 +/- 3 ng Se ml-1, respectively. The ranges for each kind of milk, especially for mature milk, were narrow. For all cases studied, the Se concentration in milk decreased with lactation time, reaching a plateau, at 17 ng Se ml-1, after 20 days. It is estimated that breast-fed-only babies in Greece receive approximately 5-11 micrograms Se day-1 up to 6 months of age. From consumed food data it was estimated that adult Greeks receive 100 +/- 6 micrograms Se day-1, in close agreement with our previously determined value of 110 micrograms Se day-1 estimated from food disappearance data.

Adult↗
PubMed1991

Selenium tolerance, salt tolerance, and selenium accumulation in tall fescue lines.

High levels of soil salinity and Se concentration are coexisting problems in the San Joaquin Valley, California. Tall fescue is a potentially useful crop plant for land management in soils containing elevated concentrations of Se and salinity. Information regarding its physiological mechanism and genetic variation of Se accumulation in this species is scant. Thirteen tall fescue (Festuca arundinacea Schreb.) lines were examined for Se and salt tolerances and Se accumulation in nutrient solution culture. Genetic variation of both Se and salt tolerances was detected among six American cultivars and seven worldwide tall fescue lines. Selenium tolerance and salt tolerance are independent of each other and are negatively correlated with tissue Se and salt concentrations. These relationships suggest that an exclusion mechanism is responsible for the tolerance. This diversity of Se and salt tolerance and Se accumulation among the tall fescue lines is important for the application of this species for land management.

Genotype↗
PubMed1991

Chemical forms of selenium in selenium containing proteins from human plasma.

The chemical forms of selenium (Se) were determined in human plasma fractions. Human plasma was subjected to gel filtration using Sephadex G-150, and the first Se peak from this column was subsequently chromatographed on DEAE-Sephacel. The form of Se in the Se peak which eluted from this column was shown to be selenocysteine (SeCys). In a second approach human plasma was again subjected to gel filtration and the first Se peak was chromatographed on Affigel blue. SeCys was shown to be the form of Se in both the retained and unretained Se on this column. The second gel filtration Se peak was also chromatographed on Reactive Blue 2-Sepharose CL-6B and the form of Se which was not retained was also shown to be SeCys. However, the form which was retained was shown to be selenomethionine. Evidence is presented that there are three Se containing proteins in human plasma, which are selenoprotein P, glutathione peroxidase, and albumin.

Blood Proteins↗
PubMed1995

Selenium distribution and metabolic profile in relation to nutritional selenium status in rats.

The disposition of selenium (Se) was investigated in Wistar rats of various Se status after an intravenous injection of 82Se-selenite. Various fractions of plasma, urine, and cytosols from liver and kidney were separated by high performance liquid chromatography (HPLC), coupled with an inductively coupled argon plasma-mass spectrometry (ICP-MS). The technique allowed simultaneous differentiation of the fate of injected and endogenous Se, and if it was influenced by the previous Se burden in the tissues. A broad Se-peak from plasma was resolved in two fractions by assessing the m/z 82/78 ratios. Urinary profiles indicated that the metabolism of Se was dose-dependent; monomethylselenol being the primary metabolite of Se in untreated animals, whereas noticeable amount of trimethylselenonium ion was detected after the injection of 82Se. Liver and kidney cytosols contained complex Se-enriched fractions, a positive identification of which was not done in this study. In most cases, the enrichment of tissue fractions with the stable isotope was altered by the dietary Se levels, the isotope nevertheless was exchanged with the endogenous Se in various macromolecules to a varying degree.

Animals↗
PubMed2005

The selenium intake of the female chicken influences the selenium status of her progeny.

The primary purpose of this study is to determine the extent to which the effects of dietary supplementation of the female chicken with selenium (Se) continue into the next generation. An additional aim is to compare the relative effectiveness of pre-hatch (from the hen's diet) with that of post-hatch (from the progeny's diet) supplementation with Se on the Se status of the chick during the first 4 weeks of post-hatch life. Hens were maintained on control or Se-supplemented diets, respectively containing 0.027 and 0.419 mug Se/g of feed. The high-Se diet elevated the Se content of the hens' eggs by 7.1-fold. At hatch, the concentrations of Se in the liver, breast muscle and whole blood of the chicks originating from the high-Se parents were, respectively, 5.4-, 4.3- and 7.7-fold higher than the values in the chicks of the low-Se parents. When the offspring from the two parental groups were both maintained on the low-Se progeny diet, the tissue Se concentrations in chicks originating from the high-Se hens remained significantly higher for 3-4 weeks after hatching, compared with the values in chicks from the low-Se hens. Similarly, tissue glutathione peroxidase activity remained significantly higher in chicks from the high-Se hens for 2-4 weeks post-hatch. Thus, the effects of maternal Se supplementation persist in the progeny for several weeks after hatching. However, when chicks hatching from low-Se eggs were placed on a high Se diet, their tissue Se concentrations at 7 days of age were markedly higher than the values in chicks from high-Se eggs placed on the low-Se diet.

Animals↗
PubMed2005

Characterizing kinetics of transport and transformation of selenium in water-sediment microcosm free from selenium contamination using a simple mathematical model.

This study developed a seven-compartment model for predicting the fate of selenium (Se) in an aquatic environment containing a water-sediment boundary. Speciation of Se in water-sediment microcosms under microaerobic conditions was measured to evaluate first-order kinetics of Se transportation and transformation. The microcosm consisted of a 10-ml solution containing 1mM soluble Se as selenate (Se6+) or selenite (Se4+) and 8 g wet sediment that was free from Se contamination, sampled from the Senri, Yamato, or Yodo Rivers in Osaka, Japan. Stepwise reaction coefficients describing transportation and transformation were determined using an inverse method on this model which includes: selenate (Se(W)6+) and selenite (Se(W)4+) in ponded water; selenate (Se(S)6+) and selenite (Se(S)4+), elemental Se (Se0), organic Se (Se2-) in sediment; and gaseous Se (DMSe). During this 1-month experiment, soluble Se was transported from ponded water to the sediment and Se was transformed sequentially to other Se species through biochemical reactions. Experimental and kinetic analyses indicated quantitatively that the Yamato River microcosm, with its high organic matter content, had a high adsorption rate of soluble Se. The Yodo River microcosm had a low adsorption rate for Se6+ and a low Se reduction rate. The Senri River microcosm had an apparent high volatilization rate of DMSe. The model developed in this study is extremely useful for predicting fate of Se in aquatic environment in the field.

Biological Transport↗