Blood Selenium Concentrations Research Articles

Trace element and vitamin concentrations and losses in critically ill patients treated with continuous venovenous hemofiltration.

To measure the blood concentrations of a number of trace elements and vitamins in critically ill patients and examine their elimination by continuous venovenous hemofiltration (CVVH). Intensive care unit of a tertiary institution. Prospective, controlled, clinical study. Eight critically ill patients requiring renal replacement therapy, nine patients requiring intensive care treatment but not requiring renal replacement therapy, and nine healthy controls. Measurement of trace element and vitamin concentrations in blood and ultrafiltrate. Compared with normal volunteers, critically ill patients requiring CVVH had significantly lower median blood concentrations of vitamin C, vitamin E, selenium, and zinc. During the first 24 hrs of CVVH, there were no changes in the trace element and vitamin concentrations in blood, nor were there differences between pre- and postfilter samples. Micronutrient losses in the ultrafiltrate were small or undetectable except for Vitamin C, chromium, and copper. Compared with normal volunteers, critically ill patients not requiring CVVH also had significantly lower median blood concentrations of vitamin C, vitamin E, selenium, and zinc. There were no differences between the two critically ill groups. The clinical significance of the reductions in blood concentrations of selenium, zinc, vitamin C, and vitamin E in critically ill patients and the ultrafiltrate losses of Vitamin C, copper, and chromium remains unclear.

The influences of dietary selenium and vitamin E intakes on milk somatic cell counts and mastitis in cows.

Dietary supplements of selenium and vitamin E in greater amounts than are required for nutritional adequacy can have complementary functions in reducing somatic cell counts and both the severity and duration of clinical mastitis. Selenium inadequacy is geographically widespread and can frequently be a year-round problem. In contrast, an adequate intake of fresh grass and quality grass silage or other green, leafy material should provide adequate vitamin E. Many observations indicate that in farm situations where there is good udder hygiene and where long-acting antibiotic treatment is given at drying off, significant correlations are found between the mean bulk milk somatic cell counts and the blood selenium concentration or glutathione peroxidase activity in the blood, even where plasma vitamin E concentration is fully adequate. The accompanying reduced incidence of clinically affected quarters diminishes the need for corrective antibiotic treatment during lactation. Presentation of selenium and vitamin E within a sustained-release rumen bolus system during the dry period and into the succeeding lactation is a convenient means of supplementation to avoid over- or under-consumption by individual cows within a group. Adequate hygiene of the environment, the milking equipment and the udder are essential.

Selenium accumulation in captive american kestrels (Falco sparverius) fed selenomethionine and naturally incorporated selenium

AbstractMale–female pairs of kestrels were maintained for 11 weeks on diets containing 5 or 9 ppm selenium (Se) (dry weight) as seleno‐L‐methionine, or naturally incorporated Se in the form of mammals collected at Kesterson Reservoir, CA, USA. Selenium concentrations in blood and excreta of male and female kestrels within groups were similar. Near‐maximal mean Se concentrations in blood were observed after the 5th week of treatment in the seleno‐L‐methionine‐treated kestrels, and an approximately 1:1 ratio was observed between maximal blood concentrations and dietary concentrations. All treatment groups exhibited reduction of Se concentration in excreta, but not in blood, to baseline values 4 weeks after treatment ended. No birds were observed to exhibit signs of general illness or Se toxicity during the study.

Interactions between essential and toxic elements in lead exposed children in Katowice, Poland

Objectives: To determine the influence of the essential element status on blood concentrations of lead and other toxic metals. Design and methods: A group of 157 children from Katowice, an industrial area in Poland, was investigated for concentrations of lead and cadmium in whole blood, and mercury, selenium, zinc, copper, and magnesium in whole blood and serum. Relations between these elements, serum ferritin, hematological parameters, as well as serum selenoprotein P and glutathione peroxidase (GSH-px) were examined. Conversion factors for element concentrations (μmol to μg): lead 207.19, cadmium 112.41, mercury 200.59, selenium 78.96, magnesium 24.31, copper 63.55, and zinc 65. Results: Blood lead was negatively associated with concentrations of selenium in whole blood and serum as well as selenoprotein P and glutathione peroxidase in serum. The association was mainly apparent at low blood lead concentrations, which may indicate an influence of selenium on the kinetics of lead, rather than an effect of lead on the selenium status. Children with low serum ferritin levels had statistically higher blood cadmium levels and a tendency for higher blood lead levels, indicating increased gastrointestinal absorption of these metals at reduced iron stores. Blood lead was negatively correlated with mean corpuscular hemoglobin concentration, which may reflect the effect of lead on hemoglobin synthesis. There was an association between blood mercury and selenium, indicating a common source of intake through fish consumption. Conclusions: The results indicate that selenium and iron status may influence the kinetics of lead.

Case control study of diarrhoea and faecal soiling in two to six-month-old lambs

A case control study was nested within a longitudinal study of faecal soiling on eight commercial farms in the south west of England. Eighty-two incident cases of faecal soiling in...

The effect of injectable barium selenate on the selenium status of horses on pasture

Aim. To examine the effect of intramuscular barium selenate on the blood selenium concentration of horses with marginal selenium status. Methods. Eighteen mares were assigned to one of six groups. The mares in groups 1–4 received barium selenate at 0.5, 0.75, 1.0 and 1.5 mg Se/kg, respectively, injected into the right pectoral muscle mass. The mares in group 5 received sodium selenate at 0.05 mg Se/kg orally at 8-week intervals. The mares in group 6 were left untreated. Ellood samples were collected at 0, 1, 2, 5, 10, 30, 60, 90, 120, 180, 240, 300 and 360 days after the initial treatment for assay of whole blood and plasma selenium. Injection site reactions were recorded on each sampling date. Results. Treatment with barium selenate at each dose rate significantly increased whole blood, plasma and blood cell selenium concentrations when compared to no treatment or oral treatment with sodium selenate, and maintained group mean whole blood selenium concentrations in the adequate range (> 1600 nmol/1) until the end of the experimental period of 1 year. The severity of injection site reactions increased with dose rate but was considered acceptable at the lower dose rates used. Conclusion. The injection of barium selenate placed aseptically at a deep intramuscular site was efficacious in correcting the selenium status of mares grazing pasture with a selenium content of 0.01–0.07 mg/kg DM. However, some swelling and fibrosis at the injection site was apparent at all dose rates used. Clinical relevance. There is currently no long-acting selenium supplementation product licensed in New Zealand for use in horses. Barium selenate promises to provide a useful method for selenium supplementation for horses, with an effective duration of at least 1 year following a single injection.

P4D77 - Blood plasma selenium concentration and glutathione peroxidase activity in bal and blood of rats exposed to NO x

P4D77 - Blood plasma selenium concentration and glutathione peroxidase activity in bal and blood of rats exposed to NO x

Selenite and selenium yeast as feed supplements to growing fattening pigs.

Twenty-four cross-bred fattening pigs weighing, on average, 24 kg were divided into three equal groups and fed a basic diet containing 0.1 mg selenium/kg. The diet of group A was supplemented with 0.3 mg selenium/kg derived from selenium yeast, group B with 0.1 mg selenium/kg from the same source, and group C with 0.3 mg/kg from sodium selenite. The pigs were slaughtered after 103 days. There was no significant difference between the mean whole blood selenium concentration of the pigs supplemented with selenium yeast neither after five nor after nine weeks of supplementation (group A, 201 and 213 micrograms/litre; group B 192 and 201 micrograms/litre, respectively), but the group supplemented with selenite had significantly lower concentrations both after five and nine weeks (158 and 159 micrograms/litre, respectively). There were no significant differences between the mean activity of glutathione peroxidase (GSH-Px; in the whole blood of the three groups (group A, 348 and 327 mukat*/litre, group B, 342 and 302 mukat/litre; group C, 332 and 300 mukat/litre, after five and nine weeks, respectively). The concentration of selenium in the liver of the pigs supplemented with organic selenium was significantly higher than in the pigs supplemented with selenite (group A, 0.54 mg/kg wet weight; group B, 0.54 mg/kg; group C, 0.40 mg/kg). No deposits of lipofuscin or ceroid pigments were observed in the histological preparations of liver and heart from any of the pigs.

Metabolism of selenium in humans

Selenium (Se) metabolism in humans is discussed. More selenium as selenomethionine (Semet) is absorbed than when it is present as selenite (95-97% vs. 44-70%). The selenium content in blood is correlated with GPX activity in selenium-deficient Chinese and in New Zealanders, but it is not correlated in blood of subjects living in the states of Oregon or South Dakota in the United States. Selenium from Semet accumulates in blood at a faster rate than selenate, but there are no differences in the GPX activities. Similarly, no differences occurred in the accumulation of selenium in GPX when Semet was compared to selenate, but a difference was found in the accumulation of selenium in hemoglobin (erythrocytes) and albumin (plasma) in subjects taking these two forms of selenium. The majority of selenium in plasma is usually present in selenoprotein P, but with high intakes of Semet, the amount in albumin predominates. Stable isotopes were used to develop the concept of “selenite exchangeable pool,” which can be employed to assess the body burden of selenium in humans. The renal clearance of selenium is higher for Semet than selenate. Even though the maximum safe intake of selenium for humans was estimated to be 600 μ per day, with use of a safety factor, 400 μ was suggested as the maximum safe intake on a long-term basis. An intake of 40 μ was suggested as the minimum amount required for humans, and intakes of less than 11 μ will definitely put people at risk of deficiency. J. Trace Elem. Exp. Med. 11:227–240, 1998. © 1998 Wiley-Liss, Inc.

Metabolism of selenium in humans

Selenium (Se) metabolism in humans is discussed. More selenium as selenomethionine (Semet) is absorbed than when it is present as selenite (95-97% vs. 44-70%). The selenium content in blood is correlated with GPX activity in selenium-deficient Chinese and in New Zealanders, but it is not correlated in blood of subjects living in the states of Oregon or South Dakota in the United States. Selenium from Semet accumulates in blood at a faster rate than selenate, but there are no differences in the GPX activities. Similarly, no differences occurred in the accumulation of selenium in GPX when Semet was compared to selenate, but a difference was found in the accumulation of selenium in hemoglobin (erythrocytes) and albumin (plasma) in subjects taking these two forms of selenium. The majority of selenium in plasma is usually present in selenoprotein P, but with high intakes of Semet, the amount in albumin predominates. Stable isotopes were used to develop the concept of “selenite exchangeable pool,” which can be employed to assess the body burden of selenium in humans. The renal clearance of selenium is higher for Semet than selenate. Even though the maximum safe intake of selenium for humans was estimated to be 600 μ per day, with use of a safety factor, 400 μ was suggested as the maximum safe intake on a long-term basis. An intake of 40 μ was suggested as the minimum amount required for humans, and intakes of less than 11 μ will definitely put people at risk of deficiency. J. Trace Elem. Exp. Med. 11:227–240, 1998. © 1998 Wiley-Liss, Inc.

Influence of Gender on Selenoprotein W, Glutathione Peroxidase and Selenium in Tissues of Rats

After feeding a commercial rodent chow for 8 weeks, tissues from male and female rats were collected and examined for selenium content, glutathione peroxidase (GPX) activities and selenoprotein W (Se-W) levels. There were no differences (P > 0.05) between plasma selenium content, plasma GPX activity, whole blood selenium content, or whole blood GPX activity between male and female rats. There was also no gender effect on selenium concentration in muscle, brain, spleen, and skin, but selenium concentration in liver was higher (P < 0.05) in female than in male rats. Western blots indicated that the tissue distribution of Se-W was similar in male and female rats. Se-W protein level was high in testes of male rats but very low in ovaries of female rats. Muscle and skin from female rats had significantly higher (P < 0.05) Se-W levels than from male rats. Consistent with Se-W content, the Se-W mRNA levels from female skins were significantly higher (P < 0.05) than from male rats. The expression of Se-W was different in various tissues and gender influenced this regulation in some tissues.

Decreased selenium concentration in maternal and cord blood in preterm compared with term delivery.

The Se concentration in maternal and cord whole blood and plasma was determined spectrofluorimetrically in: (1) 42 women at term and (2) 46 at preterm parturients, and in the placenta. The glutathione peroxidase (GSH-Px) activity was measured in red cells and plasma in maternal and cord blood of both groups. The Se concentrations and GSH-Px activities of the above-mentioned groups were compared with those of non-pregnant women. Whole blood and plasma Se concentration of parturients at term did not differ significantly from those of non-pregnant women (72.3 versus 80.3 ng ml-1 whole blood and 48.7 versus 56.2 ng ml-1 plasma). In preterm parturients, however, Se concentrations were significantly lower (61.1 ng ml-1 whole blood and 39.2 ng ml-1 plasma) when compared with term parturients. The Se levels in cord blood and plasma were similar to their mothers' Se concentrations. No difference was observed in placenta Se levels (130 ng g-1 wet weight in both groups). The same was true for glutathione (GSH): the concentration in maternal and cord blood of term and preterm parturients did not differ and varied from 2.43 to 2.50 mmol l-1 red cells. Red cell GSH-Px activities were similar in maternal and cord blood of both term and preterm groups and ranged from 14.3 to 15.7 U g-1 Hb. The plasma enzyme activity in the maternal blood of preterm parturients was significantly (p < 0.05) lower than that of mothers at term delivery. The GSH-Px activity in the plasma of cord blood was significantly (p < 0.001) lower in the preterm than in the term group. It is suggested that low Se levels in the blood of women at preterm delivery, as shown here, may be one of the causes of retinopathy and respiratory distress syndrome in preterm infants.

Study on biological activity of selenium-enriched mussel extract

In this study on the biological activity of selenium-enriched mussel extract, rats were randomly separated into three weight groups fed a basal selenium-deficient diet, diet supplemented by selenium from sodium selenite, and selenium enriched mussel extract, respectively. Body weights of the rats were determined and metabolic experiment was conducted after 4 weeks. The rats were killed after 8 weeks. Glutathione peroxidase activity and selenium content in liver and blood were determined. The results showed that selenium in mussel extract could be better absorbed by the rats and effectively promote their growth. There were no significant differences in glutathione peroxidase activity between the rats fed mussel extract or sodium selenite. Compared with sodium selenite group, the selenium content in blood and liver was significantly higher in the rats fed mussel extract.

Population-based biomonitoring in the Czech Republic — the system and selected results

In the framework of the system of monitoring the environmental impact on population health, the concentration of lead, cadmium and selenium in blood and cadmium in urine was measured in adults ( n = 670), children ( n = 599) and umbilical blood ( n = 549) using atomic absorption spectrophotometry. Furthermore, cytogenetic analysis of peripheral lymphocytes in all population groups under study was investigated. The median blood Pb level for the overall group of adults (47.8 μg/l, i.e. 0.23 μmol/l) was significantly higher in men (51.5 μg/l, i.e. 0.25 μmol/l). Smoking significantly influenced the blood Pb level in women. The 90th percentile in no group exceeded the value of 100 μg/l (0.48 μmol/l). The median blood Cd level in adults (0.9 μg/l, i.e. 0.008 μmol/l) depends on smoking habit (1.25 μg/l, i.e. 0.01 μmol/l). The median urine Cd level was 0.585 μg/g creatinine (0.59 μmol/mole creatinine) in adults and 0.37 μg/g creatinine (0.37 μmol/mole creatinine) in children. The median blood Se level (53.5 μ/l, i.e. 0.68 μmol/l) was found to be higher in the group of non-smokers (57.5 μg/l, i.e. 0.73 μmol/l). Lead and selenium level were significantly lower in the umbilical blood. Cytogenetic analysis results showed age-dependent average percentages of aberrant cells: 1.1% in umbilical blood, 1.27% in children and 1.71 in adults in line with the reference values for the Czech population.

Cadmium and selenium in blood and urine related to smoking habits and previous exposure to mercury vapour.

The object of this work was to investigate possible interactions of mercury, cadmium and selenium in humans. Selenium and cadmium in blood and urine were determined in this cross-sectional study of 130 males, of whom 77 had been previously exposed to mercury vapour at a chloralkali plant. Of the participants, 61.5% were smokers and 16.2% were never-smokers. The concentration of selenium in blood (B-Se) was significantly lower in subjects currently smoking more than 50 g of tobacco per week compared to never-smokers, whereas the concentration of cadmium in blood (B-Cd) was significantly higher in all categories of current smokers. In the multiple linear regression analysis, B-Se as a dependent variable was negatively associated with B-Cd, whereas current smoking habits were not included in the model as a predictor variable. In contrast, B-Cd as a dependent variable was positively associated with current as well as previous smoking habits, and negatively with both B-Se and the 'cumulative dose' of previous mercury vapour exposure. The concentration of selenium in blood was also negatively associated with B-Cd in the group of never-smokers (Spearman's r = -0.80; P < 0.001). In conclusion, these results suggest a depressive effect of cadmium on the concentration of selenium in blood, while smoking alone did not operate as a true predictor for this effect. Furthermore, previous exposure to mercury apparently modifies the concentration of cadmium in blood.

Decreased selenium concentration and glutathione peroxidase activity in blood and increase of these parameters in malignant tissue of lung cancer patients.

We studied the selenium (Se) concentration in whole blood and plasma, glutathione peroxidase (GSH-Px) activity in red blood cells and plasma, as well as both of these parameters in cancerous and tumor-free lung tissue of lung cancer patients. Blood samples were taken from 84 cancer patients and 61 healthy controls. Normal and neoplastic lung tissues were obtained from 57 patients at the time of surgery. Se concentrations in whole blood and plasma were lower by 23% (p < 0.001) in patients compared with controls. GSH-Px activity in red cells was lower by 20.2% (p < 0.004) and in plasma by 11.7% (p < 0.05) in patients than in the control group. On the other hand, the tumor Se level was higher by 66.6% (p < 0.0001) and GSH Px activity by 49.5% (p < 0.0001) than in adjacent tumor-free tissue. No differences in Se concentrations and GSH-Px activities were found between squamous cell carcinoma and adenocarcinoma nor among the clinical stages of the disease. In the whole blood and plasma of cancer patients significantly lower Se concentrations were found in smokers than in nonsmokers. Significantly lower Se concentrations were also found among cancer patients who were smokers compared with controls. These findings show that in the blood of cancer the antioxidant ability, as measured by Se and GSH-Px, is reduced significantly. The cause of increased Se and GSH-Px in the malignant part of the lung is not understood and requires further studies.

Influence of Se status on milk Se concentrations in dairy cows

Changes in blood and milk selenium (Se) concentrations were measured in dairy cattle grazing Se‐deficient pastures compared with animals grazing the same pasture but given either an intraruminal Se bolus or a barium selenate injection. The Se supplementation significantly increased and maintained the blood Se concentrations (e.g., 342 versus 1113 nmol/1) over 190–265 days during the lactation and also increased milk Se concentrations 2‐fold (e.g., 77.2 versus 132.3 nmol/1).

The sulfur and selenium status of pregnant ewes grazing Mediterranean pastures

Sheep require both sulfur and selenium for normal wool growth and to protect against diseases caused by free radical damage. This work describes the seasonal changes in the concentrations of sulfur, both as glutathione and inorganic sulfur, and selenium, in pregnant ewes, and the effects thereon of a multi-element supplement containing sulfate, selenium, and vitamins A and E. Merino ewes (420) were divided into 4 equal treatment groups, control (C), vitamins (V), minerals (M), and vitamins plus minerals (V+M), in a 22 factorial design. The control group was offered a loose salt lick NaCl at 175 g/head· day and the mineral group an equivalent amount of a multi-element mineral mix (Siromin). The vitamin groups were offered either salt or the mineral mix with added vitamins E and A. Treatments started 3 weeks prior to mating in November and lasted until 1 week prior to lambing in May. Sheep were sampled until weaning in September. Regardless of treatment, the concentrations of glutathione in blood and liver declined by 60% and 40%, respectively, when sheep were grazing dry pasture during summer. Sulfate-sulfur concentration in plasma of ewes in the C and V groups declined by 80% in the same period to &lt;10 mg sulfur/L, values indicative of sulfur deficiency. The mineral supplement (M) increased concentrations of plasma sulfate-sulfur at most sample times, but the V+M treatment generally did not. Glutathione concentration in blood and tissues showed little response to supplementary minerals or vitamins. Selenium concentration in blood of ewes was inversely related to the number of years since receiving a selenium pellet. Mean concentration declined to the deflcient range (0·02 mg/L) in spring in C and V ewes. Treatment with the mineral mix raised blood selenium concentrations to 0·060 mg/L within 2 months and maintained concentrations above the deficient range for several months after cessation of treatment. The results provide evidence of an under supply of sulfur during the dry summer period and of a need to administer selenium pellets at least twice in the lifetime of ewes.

Effects of selenium and vitamin e supplementation on concentrations of selenium and immunoglobulins in colostrum and blood of baluchi ewes and lambs and on lamb growth

Effects of selenium and vitamin e supplementation on concentrations of selenium and immunoglobulins in colostrum and blood of baluchi ewes and lambs and on lamb growth

A Simplified Method for the Estimation of Glutathione Peroxidase Activity and Selenium Concentration in Bovine Blood

Twelve hybridoma clones were established that produced mouse monoclonal antibodies to bovine erythrocyte glutathione peroxidase. In these monoclonal antibodies, GPF-1, GPI-2, and GPJ-1, which showed marked reaction to this enzyme, were examined for reactivity to erythrocyte lysates from 12 different species of animals and from humans and for the inhibition of glutathione peroxidase activity. GPF-1 and GPJ-1 reacted markedly with glutathione peroxidase in erythrocyte lysates from ruminants and pigs and inhibited enzymatic activity. Conversely, GPI-2 showed positive reaction to hemolysate from all mammals used, except for mice, and did not inhibit enzymatic activity. To determine the concentration of bovine glutathione peroxidase in erythrocyte lysates, a sandwich ELISA was developed using GPJ-1, both as a coated antibody and as a peroxidase-labeled antibody. This ELISA system was a sensitive procedure with a detection limit of 6ng/ml for glutathione peroxidase protein. Using blood samples from 121 cows, optical density by this ELISA was well correlated with the glutathione peroxidase activity and with the selenium concentration in bovine whole blood. The sandwich ELISA using GPJ-1 is a rapid and simple screening method to estimate glutathione peroxidase activity and selenium concentration in bovine whole blood.