Whole Blood Selenium Concentrations Research Articles

Supranutritional Selenium-Yeast Supplementation of Beef Cows during the Last Trimester of Pregnancy Results in Higher Whole-Blood Selenium Concentrations in Their Calves at Weaning, but Not Enough to Improve Nasal Microbial Diversity.

Simple SummaryWe previously showed that feeding selenium-enriched alfalfa hay to weaned beef calves diversified the nasal microbiome and improved health and growth in the feedlot, resulting in greater carcass weight and quality at slaughter. The objective of the current study was to see whether selenium supplementation of dams during various pregnancy trimesters similarly improves health and performance. Maternal supranutritional selenium supplementation during pregnancy increases selenium concentrations in calves, but is more effective the shorter the time period between maternal supplementation and assessment. Thus, calves should be fed selenium-enriched forages again at weaning in order to see a benefit in the nasal microbiome abundance and diversity, and consequently, in carcass measurements at slaughter.We previously reported that feeding Se-biofortified alfalfa hay to weaned beef calves in a preconditioning program increases whole-blood Se (WB-Se) concentrations and nasal microbiome abundance and diversity during the preconditioning period, decreases morbidity and mortality during the feedlot period, and increases carcass weight and quality at slaughter. The objective of the current study was to see whether similar improvements can be achieved through Se supplementation of dams during various pregnancy trimesters. In a two-year experimental study, 80 Angus-cross cows received once-weekly Se-yeast boluses containing 105 mg of Se, during either the first (TR-1), second (TR-2), or third (TR-3) pregnancy trimester, or were not bolused (CTR). Whole-blood Se concentrations were higher from CTR, to TR-1, to TR-2, and to TR-3 in newborn calves (all p < 0.01). At weaning, only calves from TR-3 mothers had higher WB-Se concentrations compared with calves from CTR mothers (p = 0.02), and no significant differences in nasal microbiome abundance and diversity or nasal microbiota were observed. In the feedlot period, morbidity was low, and no differences were observed. At slaughter, no differences in carcass weight and quality were observed. In conclusion, Se supplementation of pregnant cows is effective for increasing WB-Se concentration of newborn calves, and the increase can be sustained until weaning for calves born to TR-3 dams. However, the increase in WB-Se concentrations is small and does not result in beneficial changes in the nasal microbiome. Thus, calves should be fed Se-biofortified forages again at weaning in a preconditioning program in order to diversify the nasal microbiome prior to entering the feedlot.

Analysis of Whole Blood and Urine Trace Elements in Children with Autism Spectrum Disorders and Autistic Behaviors

The relationship between trace elements and neurological development is an emerging research focus. We performed a case–control study to explore (1) the differences of 13 trace elements chromium (Cr), manganese (Mn), cobalt (Co), zinc (Zn), arsenic (As), selenium (Se), molybdenum (Mo), cadmium (Cd), stannum (Sn), stibium (Sb), mercury (Hg), titanium (TI), and plumbum (Pb) concentration in whole blood and urine between autism spectrum disorder (ASD) children and their typical development peers, and (2) the association between the 13 trace elements and core behaviors of ASD. Thirty ASD subjects (cases) and 30 age-sex-matched healthy subjects from Baise City, Guangxi Zhuang Autonomous Region, China, were recruited. Element analysis was carried out by inductively coupled plasma-optical emission spectrometry. Autistic behaviors were assessed using Autism Behavior Checklist (ABC), Childhood Autism Rating Scale (CARS), and Children Neuropsychological and Behavior Scale (CNBS). The whole blood concentrations of Mo (p = 0.004), Cd (0.007), Sn (p = 0.003), and Pb (p = 0.037) were significantly higher in the ASD cases than in the controls. Moreover, Se (0.393), Hg (0.408), and Mn (− 0.373) concentrations were significantly correlated between whole blood and urine levels in ASD case subjects. There were significant correlations between whole blood Sb (0.406), Tl (0.365), Mo (− 0.4237), Mn (− 0.389), Zn (0.476), and Se (0.375) levels and core behaviors of ASD. Although the mechanism of trace element imbalance in ASD is unclear, these data demonstrate that core behaviors of ASD may be affected by certain trace elements. Further studies are recommended for exploring the mechanism of element imbalance and providing corresponding clinical treatment measures.

Maternal Dietary Selenium Intake during Pregnancy and Neonatal Outcomes in the Norwegian Mother, Father, and Child Cohort Study.

Properly working antioxidant defence systems are important for fetal development. One of the nutrients with antioxidant activity is selenium. Increased maternal selenium intake has been associated with reduced risk for being small for gestational age and preterm delivery. Based on the Norwegian Mother, Father, and Child Cohort Study and the Medical Birth Registry of Norway, we investigated the association of maternal selenium intake from food and dietary supplements during the first half of pregnancy (n = 71,728 women) and selenium status in mid-pregnancy (n = 2628 women) with neonatal health, measured as two composite variables (neonatal morbidity/mortality and neonatal intervention). Low maternal dietary selenium intake (<30 µg/day) was associated with increased risk for neonatal morbidity/mortality (adjusted odds ratio (adjOR) 1.36, 95% confidence interval (95% CI) 1.08–1.69) and neonatal intervention (adjOR 1.16, 95% CI 1.01–1.34). Using continuous variables, there were no associations between maternal selenium intake (from diet or supplements) or whole-blood selenium concentration and neonatal outcome in the adjusted models. Our findings suggest that sufficient maternal dietary selenium intake is associated with neonatal outcome. Adhering to the dietary recommendations may help ensure an adequate supply of selenium for a healthy pregnancy and optimal fetal development.

Efficacy of Long-term Selenium Supplementation in the Treatment of Chronic Keshan Disease with Congestive Heart Failure

Few effective treatments for chronic Keshan disease have been available till now. The efficacy of long-term selenium supplementation in the treatment of chronic Keshan disease with congestive heart failure is inconclusive. This study aimed to determine whether selenium supplementation is associated with a decreased risk of cardiac death in chronic Keshan disease with congestive heart failure by ten years of follow-up. A retrospective long-term follow-up analysis was performed on a monitored cohort consisting of 302 chronic Keshan disease patients with a mean age of 40.8±11.4 years. Of the 302 chronic Keshan disease patients, 170 (56.3%) were given selenium supplementation until the end point of follow-up. Cox proportional hazards regression models were used to identify the independent predictors of cardiac events. Our results showed that during the follow-up, there were 101 deaths of patients with chronic Keshan disease in the selenium supplementation group (101/170, 59.4%) and 98 in non-selenium supplementation group (98/132, 74.2%). Multivariate analyses suggested that selenium supplementation was associated with a decreased risk of cardiac death (HR 0.39, 95% CI 0.28-0.53) after adjustment for baseline age, sex, cigarette smoking, family history of Keshan disease, body mass index (BMI), heart rate, electrocardiogram (ECG) abnormalities, blood pressure, initial cardiothoracic ratio, left ventricular ejection fractions (LVEF) and whole-blood selenium concentration. Our ten-year follow-up analysis indicated that selenium supplementation, specifically combined with the use of angiotensin-converting enzyme inhibitor and beta blocker therapy, improved the survival of patients with chronic Keshan disease with congestive heart failure. BMI, selenium deficiency, male, combined ECG abnormalities, LVEF, and fast heart rate increased the risk of cardiac events.

Selenium concentration, dietary intake and risk of hepatocellular carcinoma - A systematic review with meta-analysis.

Aim: this study was performed to investigate the association between selenium concentrations, dietary intake, and the risk of hepatocellular carcinoma (HCC). Methods: we identified eligible studies in PubMed and EMBASE databases, in addition to the reference lists of original studies and review articles on this topic, up to 1 Feb 2019. A summary of standardized mean differences (SMD) with 95% confidence intervals (CI) was calculated using a random-effects model. Heterogeneity between studies was assessed using Cochran Q and I2 statistics. Results: finally, a meta-analysis showed that dietary intake of selenium and tissue selenium concentration were not associated with HCC risk (dietary SMD = -0.11, 95% CI: -0.26 to 0.03; tissue SMD = -0.12, 95% CI: -0.56 to 0.33). However, samples from toenail, whole blood, and serum all showed an inverse association with HCC risk (toenail SMD = -0.53, 95% CI: -0.72 to -0.35; whole blood SMD = -2.21, 95% CI: -2.67 to -1.76; tissue SMD = -1.26, 95% CI: -1.71 to -0.81). Dose-response data from few studies showed that an extra increase in serum selenium was dramatically related with a lower risk of HCC (adjusted p-trend < 0.05). This study showed that selenium concentration in toenail, whole blood and serum was inversely associated with HCC risk. Conclusion: increased concentration in serum selenium was related to a lower risk of HCC. However, these results based on dietary intake and tissue samples, which included few studies, did not reach statistical significance.

Investigation of Blood Selenium and Zinc in Type2 Diabetes with TCF7L2 (rs7903146 C/T) Genotypes

TCF7L2 (rs7903146) as one of the most significant single nucleotide polymorphism, is one of the associated genes with type 2 diabetes. This case-control study was performed on the whole blood of 87 patients with type 2 diabetes and 45 healthy people. Selenium and zinc concentrations in whole blood were measured using flameless atomic-absorption spectrometry. The genotype of TCF7L2 was achieved by real-time PCR and high-resolution melt (HRM). In order to data analyzing, the t-test and one-way analysis of variance (ANOVA) were used. The difference of zinc levels and also selenium levels in whole blood for both healthy (Zinc: 164.75 μgr dL-1, selenium: 140.71 μgr L-1) and patients (Zinc: 136.77 μgr dL-1, selenium: 111.66 μgr L-1) groups was significant (P-value <0.05). The different levels of zinc and selenium in healthy genotype group (TT, CT, CC) and type 2 diabetic patient genotype (TT, CT, CC) group was also significant (P-value <0.05). The presence of the T allele as a risk factor led to reducing zinc levels in healthy subjects. Significant reduction in zinc in the diabetic CT versus healthy CC and in diabetic TT versus healthy CT can be considered as a result of the T allele risk. Amount of selenium in TT genotype in both control group and diabetic patients was reduced.

Genetic polymorphisms that affect selenium status and response to selenium supplementation in United Kingdom pregnant women

Background: Low selenium status in pregnancy has been associated with a number of adverse conditions. In nonpregnant populations, the selenium status or response to supplementation has been associated with polymorphisms in dimethylglycine dehydrogenase (DMGDH), selenoprotein P (SEPP1) and the glutathione peroxidases [cytosolic glutathione peroxidase (GPx1) and phospholipid glutathione peroxidase (GPx4)].Objective: We hypothesized that, in pregnant women, these candidate polymorphisms would be associated with selenium status in early pregnancy, its longitudinal change, and the interindividual response to selenium supplementation at 60 μg/d.Design: With the use of stored samples and data from the United Kingdom Selenium in Pregnancy Intervention (SPRINT) study in 227 pregnant women, we carried out genetic-association studies, testing for associations between selenium status, its longitudinal change, and response to supplementation and common genetic variation in DMGDH (rs921943), SEPP1 (rs3877899 and rs7579), GPx1 (rs1050450) and GPx4 (rs713041). Selenium status was represented by the concentration of whole-blood selenium at 12 and 35 wk of gestation, the concentration of toenail selenium at 16 wk of gestation, and plasma glutathione peroxidase (GPx3) activity at 12 and 35 wk of gestation.Results: Our results showed that DMGDH rs921943 was significantly associated with the whole-blood selenium concentration at 12 wk of gestation (P = 0.032), which explained ≤2.0% of the variance. This association was replicated with the use of toenail selenium (P = 0.043). In unsupplemented women, SEPP1 rs3877899 was significantly associated with the percentage change in whole-blood selenium from 12 to 35 wk of gestation (P = 0.005), which explained 8% of the variance. In supplemented women, SEPP1 rs3877899 was significantly associated with the percentage change in GPx3 activity from 12 to 35 wk of gestation (P = 0.01), which explained 5.3% of the variance. Selenium status was not associated with GPx1, GPx4, or SEPP1 rs7579.Conclusions: In agreement with previous studies, we show that the genetic variant rs921943 in DMGDH is significantly associated with selenium status in United Kingdom pregnant women. Notably, our study shows that women who carry the SEPP1 rs3877899 A allele are better able to maintain selenium status during pregnancy, and their GPx3 activity increases more with supplementation, which suggests better protection from low selenium status. The SPRINT study was registered at www.isrctn.com as ISRCTN37927591.

The effect of dietary vitamin E level on selenium status in rats

The effect of varying levels of dietary vitamin E on selenium status was determined using 40 Wistar rats with similar initial body weight. The rats were equally divided into four groups and fed the following dietary treatments (mgvitaminE/kgDM): 18 (control; C-diet), 0 (0E-diet), 9 (0.5E-diet) and 36 (2E-diet) for either 4-week (Phase 1) or 8-week (Phase 2) period. At the end of experiment, animals were slaughtered to measure vitamin E and selenium levels in the brain, liver, spleen, kidney, muscles and blood tissues. Dietary vitamin E levels did not affect feed and water intake and body weight. But whole-blood selenium concentration in rats fed 0E-diet was higher than in rats fed 2E-diet after 4weeks. Selenium level in muscle, spleen and brain was also higher (p<0.05) in rats fed the 0E-diet than in rats fed C-diet after 4weeks of feeding. On the other hand, selenium level in the muscle was lower (p<0.05) in rats fed 0.5E-diet than in those fed 0E-diet after 4weeks of feeding, but not after 8weeks of feeding. Increasing dietary vitamin E level directly influenced selenium content of the spleen and brain after 8weeks of feeding 2E-diet. Moreover, the twofold increase in vitamin E intake resulted in a tendency to reduce whole-blood selenium level and total selenium in the liver and kidney after 4 and 8weeks. The results showed that the increasing dietary vitamin E level resulted in a tendency to reduce Se contents in some vital organs of the body such as the liver and kidney, suggesting their close compensatory interrelationship. Therefore, dietary vitamin E level directly influenced selenium metabolism in the animal body.

Selenium Supplementation Alters Gene Expression Profiles Associated with Innate Immunity in Whole-Blood Neutrophils of Sheep

Footrot (FR) is a common, contagious bacterial disease of sheep that results in lameness and significant economic losses for producers. We previously reported that sheep affected with FR have lower whole-blood (WB) selenium (Se) concentrations and that Se supplementation in conjunction with routine control practices accelerates recovery from FR. To determine whether oral Se-yeast administered at supranutritional levels (>4.9 mg Se/week) alters the ability of sheep to resist or recover from FR infection, 60 ewes with and 60 ewes without FR were drenched once weekly for 62.5 weeks with 0, 4.9, 14.7, or 24.5 mg organic Se-yeast (30 ewes per treatment group). Footrot prevalence and severity were measured at 0, 20, 28, 40, and 60 weeks of Se supplementation. Genomic expression of eight WB-neutrophil genes for selenoproteins and seven WB-neutrophil genes for proteins involved in innate immunity was determined at the end of the treatment period using SYBR Green and quantitative polymerase chain reaction methodology. Supranutritional Se-yeast supplementation successfully increased Se status in sheep but did not prevent FR. Supranutritional Se-yeast supplementation increased WB-neutrophil expression of genes involved in innate immunity: L-selectin, interleukin-8 receptor, and toll-like receptor 4, which were or tended to be lower in ewes affected with FR. Furthermore, supranutritional Se-yeast supplementation altered the expression of selenoprotein genes involved in innate immunity, increasing selenoprotein S and glutathione peroxidase 4 and decreasing iodothyronine deiodinases 2 and 3. In conclusion, supranutritional Se-yeast supplementation does not prevent FR, but does alter WB-neutrophil gene expression profiles associated with innate immunity, including reversing those impacted by FR.

Selenium Deficiency in Pediatric Patients With Intestinal Failure as a Consequence of Drug Shortage

Parenteral nutrition (PN) is a lifesaving therapy for children with intestinal failure and can now be used chronically without the life-threatening complications of the past. Adequate intravenous trace element supplementation is required as part of a complete nutrition prescription. According to the U.S. Food and Drug Administration (FDA), the number of drug shortages, including sterile injectable agents used as PN components, has increased since 2010. Selenious acid as an individual additive was recently unavailable at our institution for 9 months due to a national shortage. To assess the impact of the selenious acid shortage, we retrospectively compiled data from existing clinical records for eligible patients. We included children with intestinal failure on full PN support who were older than 1 year at the onset of the selenium shortage. Whole-blood selenium concentrations prior to the selenious acid shortage were compared with concentrations drawn during the shortage. Five patients with intestinal failure and complete PN dependence were identified, and all 5 patients had normal serum selenium concentrations prior to the shortage. All 5 patients developed severe biochemical selenium deficiency in direct correlation with the shortage of selenium. No morbidity associated with selenium deficiency was observed. Selenium concentrations recovered after selenium supplementation was reinstituted. A national selenious acid shortage was associated with biochemical selenium deficiency in a cohort of children with intestinal failure. Despite very low selenium concentrations, none of our patients exhibited clinical signs of deficiency.

Time-dependent effect of selenium supplementation on the relationship between selenium concentrations in whole blood and plasma of sheep

The ratio between selenium (Se) concentrations in pairs of plasma and whole blood of sheep after commencement of Se supplementation was calculated from data obtained from 10 independent investigations. The diets in the studies consisted of a variety of ingredients, from the individual feeding of feedlot diets to grazing trials on Se-deficient pastures. Means from 51 treatments, derived from 179 collections at various stages after commencement of Se supplementation, were used to calculate the ratios. In one study it was found that plasma Se concentration reached steady-state within 4 days of commencement, while Se in whole blood reached steady-state only at the collection 60 days after supplementation commenced. Using the 179 pairs, the ratio of whole blood and plasma stabilized at about 50 days after commencement when inorganic Se was supplemented, and at about 60–70 days when the Se was in the organic form. The ratios stabilized when they were between 2:1 and 3:1, and remained practically constant from 50 days post onset of supplementation, when plasma Se constituted 0.445 of whole blood Se concentration for the inorganic Se source and 0.410 when the Se source was organic. It was concluded that after commencement of Se intake, plasma Se concentration remains relatively constant from within 4 days of onset, while whole blood Se concentration apparently reaches steady-state only after approximately 50 days. Before 50 days, whole blood Se seems not to be reliable to predict the Se status of an animal. In a situation where Se intake is stable and Se requirements do not fluctuate, a bloodplasma ratio of between 2:1 and 3:1 would be a guideline to indicate that whole blood Se and plasma Se concentrations could both be used to assess the Se status of sheep.

Direct and indirect assessment of selenium status in sheep - a comparison

The aim of this study was to determine the relationship between selenium concentration and activity of glutathione peroxidase (GSH-Px) in the whole blood of sheep and reference ranges for the activity of GSH-Px for evaluation of the selenium status of sheep in the Czech Republic. Selenium concentration and activity of glutathione peroxidase were determined in whole blood samples collected from 92 sheep in six herds. The GSH-Px activity in the samples was measured using the photometric method. Selenium in the sample was measured using the hydride technique atomic absorption spectrometry. Data on both parameters were processed using correlation and regression analysis in order to obtain reference values of GSH-Px for the indirect evaluation of the selenium status of sheep. The two variables showed a close and significant correlation (r = 0.95; P &amp;lt; 0.01). The regression line, defined by the equation y = 7.5857x &amp;ndash; 121.87 (linear) or y = &amp;ndash;0.0167x&lt;sup&gt;2&lt;/sup&gt; + 11.993x &amp;ndash; 355.57 (polynomial), allowed us to determine the GSH-Px activity of 637, resp. 677 &amp;mu;kat/l as equivalent to selenium concentration in whole blood of sheep 100 &amp;mu;g/l. Mean selenium concentration and mean GSH-Px activity found in whole blood samples were 123.42 &amp;plusmn; 57.84 &amp;mu;g/l and 814.34 &amp;plusmn; 463.64 &amp;mu;kat/l, respectively. In this study, a close dependence of GSH-Px activity on the selenium concentration in the blood of sheep was found. Activity values of GSH-Px were determined for use in the diagnosis of sufficient selenium status in sheep in the Czech Republic (GSH-Px activity greater than 600 &amp;mu;kat/l of whole blood). &amp;nbsp;

The intraoperative decrease of selenium is associated with the postoperative development of multiorgan dysfunction in cardiac surgical patients*

The trace elements selenium, copper, and zinc are essential for maintaining the oxidative balance. A depletion of antioxidative trace elements has been observed in critically ill patients and is associated with the development of multiorgan dysfunction and an increased mortality. Cardiac surgery using cardiopulmonary bypass provokes ischemia-reperfusion-mediated oxidative stress. We hypothesized that an intraoperative decrease of circulating trace elements may be involved in this response. Prospective observational clinical study. University hospital cardiothoracic operation theater and intensive care unit. Sixty patients (age 65 ± 14 yrs) undergoing cardiac surgery with the use of cardiopulmonary bypass. Whole blood concentrations of selenium, copper, and zinc were measured after induction of anesthesia and 1 hr after admission to the intensive care unit. All patients were separated in a priori defined subgroups according to the development of no organ failure, single organ failure, and ≥ 2 organ failures in the postoperative period. Fifty patients exhibited a significant selenium deficiency already before surgery, whereas copper and zinc concentrations were within the reference range. In all patients, blood levels of selenium, copper, and zinc were significantly reduced after end of surgery when compared to preoperative values (selenium: 89.05 ± 12.65 to 70.84 ± 10.46 μg/L; zinc: 5.15 ± 0.68 to 4.19 ± 0.73 mg/L; copper: 0.86 ± 0.15 to 0.65 ± 0.14 mg/L; p < .001). During their intensive care unit stay, 17 patients were free from any organ failure, while 31 patients developed single-organ failure and 12 patients multiple organ failure. Multilogistic regression analysis showed that selenium concentrations at end of surgery were independently associated with the postoperative occurrence of multiorgan failure (p = .0026, odds ratio 0.8479, 95% confidence interval 0.7617 to 0.9440). Cardiac surgery using cardiopulmonary bypass resulted in a profound intraoperative decrease of whole blood levels of antioxidant trace elements. Low selenium concentrations at end of surgery were an independent predictor for the postoperative development of multiorgan failure.

Selenium concentrations and enzyme activities of glutathione metabolism in wild long‐tailed ducks and common eiders

The relationships of selenium (Se) concentrations in whole blood with plasma activities of total glutathione peroxidase, Se-dependent glutathione peroxidase, and glutathione reductase were studied in long-tailed ducks (Clangula hyemalis) and common eiders (Somateria mollissima) sampled along the Beaufort Sea coast of Alaska, USA. Blood Se concentrations were >8 µg/g wet weight in both species. Linear regression revealed that the activities of total and Se-dependent glutathione peroxidase were significantly related to Se concentrations only in long-tailed ducks, raising the possibility that these birds were experiencing early oxidative stress.

Higher whole-blood selenium is associated with improved immune responses in footrot-affected sheep

We reported previously that sheep affected with footrot (FR) have lower whole-blood selenium (WB-Se) concentrations and that parenteral Se-supplementation in conjunction with routine control practices accelerates recovery from FR. The purpose of this follow-up study was to investigate the mechanisms by which Se facilitates recovery from FR. Sheep affected with FR (n = 38) were injected monthly for 15 months with either 5 mg Se (FR-Se) or saline (FR-Sal), whereas 19 healthy sheep received no treatment. Adaptive immune function was evaluated after 3 months of Se supplementation by immunizing all sheep with a novel protein, keyhole limpet hemocyanin (KLH). The antibody titer and delayed-type hypersensitivity (DTH) skin test to KLH were used to assess humoral immunity and cell-mediated immunity, respectively. Innate immunity was evaluated after 3 months of Se supplementation by measuring intradermal responses to histamine 30 min after injection compared to KLH and saline, and after 15 months of Se supplementation by isolating neutrophils and measuring their bacterial killing ability and relative abundance of mRNA for genes associated with neutrophil migration. Compared to healthy sheep, immune responses to a novel protein were suppressed in FR-affected sheep with smaller decreases in FR-affected sheep that received Se or had WB-Se concentrations above 250 ng/mL at the time of the immune assays. Neutrophil function was suppressed in FR-affected sheep, but was not changed by Se supplementation or WB-Se status. Sheep FR is associated with depressed immune responses to a novel protein, which may be partly restored by improving WB-Se status (> 250 ng/mL).

Long-term selenium supplementation of humans: Selenium status and relationships between selenium concentrations in skeletal muscle and indicator materials

Supplementation with elevated doses of l-selenomethionine (SeM) or selenium-enriched yeast that contains SeM as the main selenium species is frequently used as a protective or therapeutic measure. Information on the effects of long-term selenium supplementation on the body selenium status is, however, rather scarce. We therefore investigated fifteen male test persons who had taken selenium yeast and/or SeM supplements in medium doses of 62.5–125 μg Se/day or high doses of 200–262.5 μg Se/day for periods ranging from 1 year to 24 years. Seven non-supplemented men served as controls. As skeletal muscle is the main selenium pool, thigh muscle biopsy samples were taken. The selenium concentrations in these biopsies and in samples of the indicator materials blood, blood plasma, blood cells, head hair and toenails were determined by neutron activation analysis. Compared with the controls, the muscle selenium level was raised with additional selenium supplementation, but the relative increase in the mean muscle selenium concentration (by factors of about 1.6 and 2 for the medium and high doses, respectively) was lower than that in the selenium intake. Highly significant correlations found between the selenium concentrations in muscle and whole blood ( R=0.90), red blood cells ( R=0.91), blood plasma ( R=0.87), head hair ( R=0.89) and toenails ( R=0.85) show that in humans supplemented in this way the selenium status can be assessed in a relatively easy way by analysis of the selenium retention in these indicator materials.

Critically elucidating the role of selenium

To assess the current role of selenium supplementation in critically ill patients. Studies consistently demonstrate decreased selenium concentration in plasma and whole blood in some critically ill patients, especially those with septic shock, and have suggested that persistent low concentrations may be associated with worse outcomes. However, clinical trials of selenium administration have not consistently or convincingly demonstrated improved outcomes. Despite the low selenium content in the body (20-40 mg), selenoenzymes play an important role in antioxidant defense in humans. Selenium administration may be associated with improved outcomes, but further studies are needed to determine the precise mechanism of action. Studies are also needed to determine optimal dosing regimens, and to identify those patients in whom this approach is likely to be most effective. Currently, doses below the tolerable upper intake level (400 microg) may be used in supplementation. Higher doses (up to the level of no adverse effect, 800 microg) may be of interest and need to be studied further. The pro-oxidant effects of selenocompounds, especially sodium selenite, which vary depending on the compound, dose, and concentration, also need to be assessed further for their toxicity and potential therapeutic use in patients with septic shock.

Nutritional myodegeneration as a cause of dysphagia in adult horses: three case reports

Three cases of nutritional myodegeneration caused by selenium deficiency in adult horses are described. Difficulty in eating and drinking was a common clinical sign in all horses. Blood biochemistry revealed a marked elevation of muscle enzymes and low glutathione peroxidase activity or low selenium concentration in whole blood in all cases. The treatment with sodium selenite and vitamin E was instituted in all horses. Two of them were euthanized because of continuing muscle injuries, one patient was cured. The post-mortem examination of euthanized horses revealed pale muscles that were distributed with bilateral symmetry on hind and thoracic limbs, diaphragm, tongue, masticatory and intercostal muscles and the myocardium. Histopathology revealed the areas of degeneration and necrosis. Large groups of regenerating fibres and pronounced lymphoplasmocytic reaction among the groups of intact fibres were also present. The clinical outcome of the disease is probably influenced by timely diagnosis and treatment.

Selen in der Tumorprävention

Krebs ist eine der wichtigsten Todesursachen in den Industrieländern, und daher wurde in den letzten Jahren über Präventionsmöglichkeiten diskutiert, z.B. die Anwendung von Selenpräparaten. Beginnend mit den siebziger Jahren des letzten Jahrhunderts sind eine große Anzahl von Veröffentlichungen erschienen, die im Allgemeinen einen inversen Zusammenhang von Selenkonzentrationen im Vollblut oder Serum und dem Risiko für das Auftreten bestimmter Tumorerkrankungen belegen. Nachdem einige Interventionsstudien beim Menschen zur Krebsprävention durch Selen vielversprechende Resultate lieferten, wurde die so genannte SELECT-Studie aufgelegt, die bislang größte doppelblinde und placebokontrollierte Studie zur Prävention von Prostatakrebs. Der Beitrag gibt einen Überblick über die bislang publizierte Literatur.

Cadmium, Lead, and Selenium in Cord Blood and Thyroid Hormone Status of Newborns

Cadmium (Cd), lead (Pb), and selenium (Se) concentrations in cord whole blood, sampled from 24 women at the time of delivery in a hospital in Tokyo in 2005, were determined by inductively coupled plasma mass spectrometry with a reaction cell. Signal enhancement caused by nonspectroscopic interference for Se was evident and the standard addition technique was essential for correcting the interference. Median concentration in cord bloods was 0.20 ng/g, 6.7 ng/g (0.67 microg/dL), and 191 ng/g for Cd, Pb and Se, respectively. Lead concentration was lower, whereas Se concentration was higher, than those reported in other countries. The trace element concentration was related to the levels of thyroid stimulating hormone (TSH) and free thyroxin (fT4) in the neonatal blood sampled at 4-6 days postpartum. A significantly negative correlation was observed between Cd concentrations in cord blood and TSH concentration in neonatal blood. The result indicated the possible effect of in utero Cd exposure on thyroid hormone status of newborns and that Cd exposure level should be assessed as a covariate in the survey on the relationship between in utero chemicals (e.g., PCBs) exposure and thyroid hormone status.