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PubMed1990

The biological response of selenium in individual erythrocytes and GSH-Px in lambs fed sodium selenite or selenium yeast.

Twenty Swedish Landrace lambs were divided randomly into two equal groups, group I and group O. Group I received approximately 0.1 mg selenium as sodium selenite per day and group O 0.1 mg selenium as selenium in yeast per day. The animals were fed per day 1.2-1.5 kg of hay and 0.3 kg of a commercial concentrate supplemented with vitamins and minerals. The trial lasted 3.5 months. As monitored by micro particle induced X-ray emission (mu-PIXE), the number of selenium bearing erythrocytes increased faster in group O than in group I indicating some difference in the metabolism of inorganic and organic selenium. During the trial the concentration of sulphur decreased in the erythrocytes in group O. The reason for this is not known. The zinc and copper concentrations of individual erythrocytes were unaltered. The blood GSH-Px activity increased at the same rate in the two groups indicating that selenium as sodium selenite and selenium in yeast was about equally available. The rate of growth in the two groups was almost the same and a significant difference in the final weight was not observed.

Animals↗
PubMed1977

Selenium content of tissues in Finnish infants and adults with various diseases, and studies on the effects of selenium supplementation in neuronal ceroid lipofuscinosis patients.

A low blood selenium level has previously been observed in healthy inhabitants of Finland (WESTERMARCK et al. 1977). In this study even lower blood selenium values were observed in patients with acrodermatitis enteropathica, dystrophia musculorum progressiva (Duchenne), infantile and juvenile type of neuronal ceroid lipofuscinosis (NCL), severe mental retardation caused by various factors, and myocardial infarction. The selenium content of the brain, heart, kidney and liver in patients of different ages was also determined. The highest selenium level was found in the kidney. The mean liver selenium concentrations in stillborn, premature and full-term neonates were 1.11 +/- 0.23 (8), 1.21 +/- 0.17 (12) and 0.93 +/- 0.16 microgram/g dry weight (12) respectively (the number of subjects in parentheses). The selenium values are considerably higher than those in infants of from one to nine months of age and adults, whose liver selenium values were 0.58 +/- 0.21 (8) and 0.67 +/- 0.08 microgram/g dry weight (8) respectively. The vitamin E levels of serum in patients with NCL, as well as in subjects with severe mental retardation (controls), were low compared with values in healthy normal subjects. Sodium selenite supplementation in patients with NCL produced at least a transitory improvement without causing any toxic effects during one year of administration.

Acrodermatitis↗
PubMed1985

Selenium and haemodialysis: serum selenium levels in healthy persons, non-cancer and cancer patients with chronic renal failure.

In 40 healthy persons, 11 nondialyzed uremic patients and 27 dialyzed uremic patients, of whom 4 also had cancer, the selenium concentration in serum was determined. The mean serum selenium concentration in healthy persons was 13.6 +/- 0.8 micrograms/dl, in nondialyzed patients 11.9 +/- 1.9 micrograms/dl and in dialyzed uremic patients 11.3 +/- 1.0 micrograms/dl. There was a significant statistical difference between healthy persons and uremic patients (p less than 0.001), but not between dialyzed and nondialyzed uremic patients. The subgroup of cancer patients on hemodialysis also had low serum selenium concentrations. The possible role of low selenium levels as one of the factors responsible for the increased incidence of malignancy in patients with chronic renal failure is supported by several facts such as: low serum selenium levels detected in patients with malignant diseases; the higher cancer incidence in inhabitants of low-selenium areas, and the known ability of selenium to inhibit many types of experimental carcinogenesis.

Adolescent↗
PubMed1982

Response of cows consuming adequate selenium to vitamin E and selenium supplementation prepartum.

A 2-yr study of 195 parturitions was to evaluate the prepartum need for supplemental vitamin E and selenium by cows consuming diets that contained ample amounts of selenium (.1 to 2.0 ppm selenium). One-half of the cows were injected with 68 IU vitamin E and 5 mg selenium per 45.4 kg body weight approximately 21 days prepartum. Incidences of retained placenta and calving difficulty were similar for treated and control cows. There was a lower incidence of retained placenta (7.5%) for cows that calved during fall, whereas incidence was greater than 20% in cows that calved during the rest of the year. Serum vitamin E and selenium concentrations in treated cows doubled within a day after injection, then declined to concentrations typical of untreated cows within 8 and 3 days postinjection, respectively. Serum carotene, vitamin A, and vitamin E concentrations were similar for treated and control cows and were elevated in cows that calved during the summer and fall, possibly because cows dry during the grazing season were pastured. However, discriminant analysis of 21-day prepartum serum data indicated that serum concentrations of carotene, vitamins A or E, or selenium would not predict accurately the retention of the placenta. Colostrum and 4-day milk from treated and control cows contained similar amounts of vitamin E and selenium.

Animals↗
PubMed1975

Influence of dietary selenium on tissue selenium levels in turkeys.

To study the influence of dietary supplements of selenium on tissue selenium levels, duplicate groups of 20 Broad Breasted White turkeys were fed practical diets alone or supplemented with 0.1 and 0.2 p.p.m. Se as Na2SeO3. The concentration of naturally occurring selenium in the basal starting and finishing rations was 0.20 and 0.13 p.p.m. respectively. Selenium analyses were performed on samples of blood, liver, breast muscle and leg muscle obtained at 14 and 20 weeks of age. Supplemental selenium did not change the level of selenium in any of the tissues studied, nor did it affect weight gains. The concentration of selenium in blood and muscle was approximately 0.2 p.p.m. and ranged from 0.6 to 0.7 p.p.m. in liver. The results indicate that supplementing diets containing marginal levels of Se with 0.2 p.p.m. Se as Na2SeO3 does not lead to accumulation of Se in the tissues.

Administration, Oral↗
PubMedDate not supplied

[The selenium haemostasis during experimental anaphylaxis reaction in rats treated with reduced glutathione and selenium enriched spirulina].

The main events caused by anaphilaxis in selenium haemostasis in rats include significant increase of selenium excretion with urine (6.36 +/- 1.18 nM Se/18 h., n = 10, compared with 1.72 +/- 0.38 nM Se/18 h., n = 10) and decrease of selenium plasma/selenium erythrocytes ratio from 0.939 to 0.791. Reduced glutathione (G-SH) administration led to 1.5-fold decrease of plasma selenium level and 1.3-fold increase of selenium concentration in intestinal walls of sensitized rats (r = -0.720, P < 0.001). Chromatographic separation of plasma proteins showed that intragastric intubation of G-SH to sensibilized rats significantly decreased the protein P content and did not influence the concentration of Se-GSHPx, thus indicating the local selenium acceptor role of G-SH. G-SH administration did not influence the intestinal permeability in sensitised rats while use of complex additive: G-SH and selenium enriched spirulina--normalized the latter parameter and the ratio of protein P/Se-GSHPx in plasma.

Anaphylaxis↗
PubMed1999

[Priority of selenium incorporation into selenoproteins during selenium depletion in rats].

Male weanling Wistar rats were fed with either a basal selenium deficient diet (a Torula yeast based semisynthetic diet, containing Se 0.01 mg/kg) or a selenium sufficient diet supplemented with Se as Na2SeO3 (containing Se 0.5 mg/kg). Rats were killed after different weeks(0,1,2,4,8,12,15,17,19,20 and 24 respectively). Their organs were taken to observe the kinetic change of selenium concentration, the activities of intracellular glutathione peroxidase (cGPX), extracellular glutathione peroxidase (eGPX), and phospholipid hydroperoxide glutathione peroxidase (PHGPX) in different organs. The results showed that selenium levels and the activities of selenoenzyme in testis and pituitary were more resistant to selenium deficiency than other organs. During selenium deficiency, the utilization of selenium by PHGPX and deiodinase was prior to eGPX and cGPX, which suggested that the function of PHGPX and deiodinase were more important than that of eGPX and cGPX.

Animals↗
PubMed2003

[Selenium sufficiency in patients with malabsorption syndrome and its optimization with selenium enriched food supplements].

Selenium security was measured in 15 adult patients suffering from malabsorption syndrome, resulted from stomach and small intestine surgical resection consequences. In 7 of them (47%) marked deficiency of this essential trace element was revealed and in other 6 (40%)--suboptimal security. The indices of selenium security in observed patients markedly and significantly (p < 0.003) increased after a 3-week course of dietetic treatment including uptake of organic selenium enriched food supplement in amount equal to 90 mcg Se per day. This dietetic treatment had mild "physiologic" character that became apparent from the observation that the largest serum selenium increase was noticed in patients with largest degree of selenium insufficiency. It's concluded that there is certain testimony for selenium security correction in malabsorption patients by means of selenium enriched food supplement.

Bacterial Proteins↗
PubMed1990

Blood serum selenium in the province of Mérida, Venezuela, related to sex, cancer incidence and soil selenium content.

Blood serum selenium levels were measured in healthy subjects of six districts located throughout the province of Mérida, Venezuela. There were either high (87-115 micrograms/L) or low (58-72 micrograms/L) serum selenium-containing districts. Serum selenium in males from three districts were statistically significantly lower (p less than 0.001) than in females. There was a general tendency for serum selenium to increase with age. On the average, a reduction in cancer was observed in the districts with high serum selenium content. Further, serum selenium was lower in male patients from the Mérida district with cancer disease. Association between selenium in soil and in the blood serum of healthy subjects has been observed.

Adolescent↗
PubMed1993

The effects of selenium supplementation on antioxidative enzyme activities and plasma and erythrocyte selenium levels.

Plasma and erythrocyte selenium levels in rabbits supplemented with therapeutic doses of selenium were studied by Zeeman graphite furnace atomic absorption spectrometry using a new palladium-ascorbic acid chemical modifier in order to achieve a higher precision. An improved coupled test procedure was used to determine the glutathione peroxidase (GSH-Px) activities. Superoxide dismutase activities were measured employing a method for the clinical assay of the enzyme. The selenium levels and GSH-Px activities both in the plasma and erythrocytes were higher in the supplemented group when compared to the controls. The SOD activities were increased in the erythrocytes but remained unchanged in the plasma. Or the other hand, a higher copper/zinc ratio was found both in the plasma and erythrocytes of the supplemented group. These findings support the importance of the dietary selenium intake in terms of the principal role of selenium in the cellular antioxidative mechanisms and imply that measurements of plasma selenium levels may be a notable sensitive indicator of the short-term selenium status.

Animals↗
PubMed1997

[Selenium content in blood of cattle in the Weser-Ems region and effects of Se fertilization of pasture grounds on Se levels in growth and in blood dairy cattle with extreme selenium deficiency].

The evaluation of 1.974 selenium levels in samples of bovine blood mainly from the Weser-Ems region showed a high rate of selenium deficiency in calves, young cattle and heifers ante partum. More than 50% of cows showed Se deficiency, too. After fertilizing of pasture grounds exhibiting extreme selenium deficiency with 35 g of selenium per hectare, the authors found significantly positive effects on plant selenium levels and in blood of grazing young cattle. At the same time, the selenium contents in blood of the control animals decreased extremely as the result from being cut off from the selenium supply in the young stock shed during winter time.

Animal Feed↗
PubMed2006

Laser desorption/ionization and laser ablation synthesis of new selenium oxide compounds from selenium(IV) dioxide.

Laser desorption/ionization (LDI) and/or laser ablation (LA) of selenium dioxide crystals or its mixtures with sodium peroxide were studied using a commercial matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometer. It was found that LDI and LA of selenium (IV) dioxide not only ionizes SeO(2), but also leads to the formation of several positively and negatively singly charged species: SeO(n) (+) (n = 0-2), Se(2) (+), SeO(n) (-) (n = 0-4), Se(2)O(n) (-) (n = 3-7), Se(3)O(n) (-) (n = 4-9), Se(4)O(n) (-) (n = 8-10). A rather high yield of selenium species in the positive ion mode, Se(m) (+) (m = 1-8) and Se(m)OH(+) (m = 3-7), was obtained by using the MALDI approach while the species detected in the negative ion mode, SeO(n) (-) (n = 0-4), Se(2)O(n) (-) (n = 3-7), Se(3)O(n) (-) (n = 4-9), and Se(4)O(n) (-) (n = 9, 10), were the same as those observed during LDI/LA of selenium dioxide. The addition of sodium peroxide to selenium dioxide with the aim of enhancing its oxidation and thus increasing the production of SeO(4) product resulted in extensive cationization of the species with sodium or potassium. The following positively and negatively charged species were identified: Se(+), Se(2) (+), Se(2)OH(+), Se(2)ONa(+), SeO(n) (-) (n = 0-3), and Se(2)O(n) (-) (n = 0, 1, 4). Also observed in mass spectra of such mixtures, various mixed sodium and/or potassium adducts with selenium oxide species, e.g. Se(2)O(4)K(2)Na(-), were identified. In all, 26 totally new species, Se(2)O(n) (-) (n = 3-6), Se(3)O(n) (-) (n = 4-9), Se(4)O(n) (-) (n = 8-10), Se(4)O(11)H(5) (-), Se(4)O(12)H(3) (-), Se(2)O(4)Na(-), Se(2)O(5)HNa(-), Se(2)O(5)HNa(2) (-), Se(3)O(6)K(2)Na(-), Se(3)O(6)K(2)Na(2) (-), Se(2)ONa(+), and Se(m)OH(+) (m = 3-7), were described for the first time. Also, for the first time, the formation of selenium(IV) diperoxide, O-O-Se-O-O or O(2)SeO(2), is described. The stoichiometries of the compounds generated were confirmed using isotopic pattern modeling.

Journal Article↗
PubMed1999

Selenium-independent epididymis-restricted glutathione peroxidase 5 protein (GPX5) can back up failing Se-dependent GPXs in mice subjected to selenium deficiency.

We have previously characterized and cloned a secreted sperm-bound selenium-independent glutathione peroxidase protein (GPX5), the expression of which was found to be restricted to the mouse caput epididymidis. Because of the lack of selenium (Se) in the active site of this enzyme, unlike the other animal GPXs characterized to date, it was suspected that GPX5 does not function in the epididymis as a true glutathione peroxidase in vivo. In the present report, following dietary selenium deprivation which is known to reduce antioxidant defenses and favor oxidative stress in relation with depressed Se-dependent GPX activities, we show that the epididymis is still efficiently protected against increasing peroxidative conditions. In this model, the caput epididymides of selenium-deficient animals showed a limited production of lipid peroxides, a total GPX activity which was not dramatically affected by the shortage in selenium availability and an increase in GPX5 mRNA and protein levels. Altogether, these data strongly suggest that the selenium-independent GPX5 could function as a back-up system for Se-dependent GPXs.

Animals↗
PubMed1978

The selenium state of children. II. Selenium content of serum, whole blood, hair and the activity of erythrocyte glutathione peroxidase in dietetically treated patients with phenylketonuria and maple-syrup-urine disease.

The selenium content of serum, whole blood and hair was measured by neutron activation analysis in dietetically treated patients with phenylketonuria (PKU) and maple-syrup-urine disease (MSUD). Follow-up studies showed a decrease of the serum selenium content and the glutathione peroxidase activity of erythrocytes--a selenoenzyme--from normal values at the beginning of the diet to 20% (selenium) and 50% (gluthione peroxidase) of normal within 10--12 weeks of dietary treatment. In 36 patients the serum selenium content was lower at 6.7--28 X 10(-9) g/ml, independent of the age of the patients (0.5 to 10 years). The selenium content of whole blood was reduced: median = 98 X 10(-9) g/g dry weight; range 75 to 165 X 10(-9) g/g dry weitht (healthy children: median = 381 X 10(-9) g/g dry weight; range 245 to 588 X 10(-9) g/g dry weight). The selenium content of hair was markedly lower in the patients (median = 62 X 10(-9) g/g; range 13--140 X 10(-9) g/g) than in healthy children (median = 429; range 213 to 720 X 10(-9) g/g). The mean glutathione peroxidase activity of erythrocytes was reduced to 4.6 +/- 0.64 U37/g Hb, comparison to normal values (mean = 8.8 +/- 0.88 U37/g Hb).

Child↗
PubMed1992

Decreased selenium intake and low plasma selenium concentrations leading to clinical symptoms in a child with propionic acidaemia.

A child with biotin-non-responsive propionic acidaemia treated with a propiogenic amino acid-restricted diet presented with an elevated blood mean corpuscular volume (MCV) of 93.1 fl, indicative of macrocytosis, and unusual hair texture with hypopigmentation. Plasma selenium concentration at this time was subnormal (45.9 micrograms/L), and calculated dietary selenium intake was 4.7 micrograms/day. After 4 months of selenium supplementation (50 micrograms/day) plasma selenium concentration normalized (97.7 micrograms/L) in conjunction with a reduced MCV (84.0 fl) and a dramatic improvement in hair growth, colour and length. Two additional periods off and on selenium supplementation, of varying time intervals, resulted in similar clinical changes. We conclude that these clinical changes were due to a deficient intake of dietary selenium.

Amino Acid Metabolism, Inborn Errors↗
PubMed1996

Selenoprotein gene expression during selenium-repletion of selenium-deficient rats.

Selenium repletion of selenium-deficient rats with 20 micrograms selenium / kg body weight as Na2SeO3 was used as a model to investigate the mechanisms that control the distribution of the trace element to specific selenoproteins in liver and thyroid. Cytosolic glutathione peroxidase (cGSHPx), phospholipid hydroperoxide glutathione peroxidase (PHGSHPx), and iodothyronine 5'-deiodinase (IDI) activities were all transiently increased in liver 16 to 32 h after ip injection with selenium. However, only cGSHPx and PHGSHPx activities increased in the thyroid where IDI activity was already increased by selenium deficiency. These responses were owing to synthesis of the seleoproteins on newly synthesised and/or existing mRNAs. The selenoprotein mRNAs in the thyroid gland were increased two- and threefold after the transitory increases in selenoprotein activity. In contrast, there were parallel changes in selenoprotein mRNAs and enzyme activities in the liver, with no prolonged rises in mRNA levels. The organ differences suggest that increased thryotrophin (TSH) concentrations, which are known to induce thyrodial IDI and mRNA, may control the mRNAs for all the thyroidal selenoproteins investigated and be a major mechanism for the preservation of thyroidal selenoproteins when selenium supplies are limited.

Animals↗
PubMed1995

Selenium concentrations in brain after exposure to methylmercury: relations between the inorganic mercury fraction and selenium.

Three groups of female monkeys (Macaca fascicularis) were exposed to methylmercury (MeHg, p.o. 50 micrograms Hg/kg body wt per day) for 6, 12, or 18 months. One group was exposed to MeHg for 12 months and kept unexposed for 6 months before sacrifice. Another group of three monkeys was exposed to HgCl2 i.v. for 3 months. Total and inorganic mercury concentrations in occipital pole and thalamus were determined by cold vapor atomic absorption spectroscopy. Selenium concentrations were analyzed by hydride generation atomic absorption spectroscopy. The results indicated an association between concentrations of inorganic mercury and selenium in both occipital pole and thalamus in the MeHg-exposed animals. A linear regression model using concentrations of inorganic mercury (nmol/g wet wt) as independent variable, and selenium concentrations (nmol/g wet wt) as the dependent variable showed significant correlations between the variables in both occipital pole and thalamus (r = 0.85 and r = 0.91, P < 0.0001). The intercept of the regression line was slightly lower (about 2 nmol Se/g wet wt) than the selenium concentrations found in control monkeys (about 3 nmol Se/g wet wt). There was a tendency to a "hockey stick"-shaped relationship between concentrations of selenium and inorganic mercury in the thalamus of monkeys with ongoing exposure to MeHg. An important role for selenium in the retention of mercury in brain is indicated.

Animals↗
PubMed1986

Cigarette smoke-induced alterations in the release of arachidonate metabolites by pulmonary alveolar macrophage from selenium-fed and selenium-deficient rats.

Male weanling F-344 rats were maintained on selenium-supplemented or -deficient diets and were exposed to fresh cigarette smoke daily for 28 weeks. The deficient status of animals was demonstrated by a significant reduction in the pulmonary and hepatic glutathione peroxidase (GSH-Px) activity of rats on selenium-deficient diet. Sham and smoke treatment did not influence the GSH-Px activity in either diet group. Elevated levels of blood carboxyhemoglobin and pulmonary aryl hydrocarbon hydroxylase activity in the smoke-exposed rats of both diet groups indicated effective inhalation of cigarette smoke by animals. Studies of the extracellular release of arachidonate metabolites by pulmonary alveolar macrophages (PAMs) indicated that resting cells released small amounts of prostaglandin E2 (PGE2), thromboxane B2 (TXB2) and leukotriene B4 (LTB4). Upon phagocytic challenge by opsonized zymosan particles, the release of the three metabolites was substantially increased in all diet and treatment groups. While the release of cyclooxygenase products, PGE2 and TXB2, remained unaffected by cigarette smoke, an inhibition of approximately 50% in the release of lipoxygenase product, LTB4, was observed in cells from selenium-fed animals. In selenium-deficient animals, cigarette smoke almost completely inhibited (greater than 80%) the zymosan-stimulated release of LTB4 by PAMs and additionally caused about 50% reduction in TXB2 release. These results suggest a specific inhibition of lipoxygenase pathway by cigarette smoke in PAMs of selenium-fed rats and suggest that cigarette smoke may additionally impair enzymes of the cyclooxygenase pathway in PAMs of selenium-deficient animals.

Administration, Oral↗