Plasma Selenium Concentrations Research Articles

Trace element monitoring in the ICU: Quality and economic impact of a change in sampling practice

Trace elements (TE) are involved in the immune and antioxidant defences which are of particular importance during critical illness. Determining plasma TE levels is costly. The present quality control study aimed at assessing the economic impact of a computer reminded blood sampling versus a risk guided on-demand monitoring of plasma concentrations of selenium, copper, and zinc. Retrospective analysis of 2 cohorts of patients admitted during 6 months periods in 2006 and 2009 to the ICU of a University hospital. to receive intravenous micronutrient supplements and/or to have a TE sampling during ICU stay. The TE samplings were triggered by computerized reminder in 2006 versus guided by nutritionists in 2009. During the 2 periods 636 patients met the inclusion criteria out of 2406 consecutive admissions, representing 29.7% and 24.9% respectively of the periods' admissions. The 2009 patients had higher SAPS2 scores (p = 0.02) and lower BMI compared to 2006 (p = 0.007). The number of laboratory determinations was drastically reduced in 2009, particularly during the first week, despite the higher severity of the cohort, resulting in à 55% cost reduction. The monitoring of TE concentrations guided by a nutritionist resulted in a reduction of the sampling frequency, and targeting on the sickest high risk patients, requiring a nutritional prescription adaptation. This control leads to cost reduction compared to an automated sampling prescription.

Effect of selenium supplementation on glutathione peroxidase enzyme activity in patients with chronic kidney disease: a randomized clinical trial.

Background:Plasma selenium (Se) concentration and glutathione peroxidase (GSH-Pxs) enzyme activity of the patients with chronic kidney disease (CKD) are usually lower than healthy individuals; however, the effect of Se supplementation on the GSH-Pxs activity in those patients remains unclear.Objectives:This study aimed to assess the effect of Se supplementation on plasma Se concentration and red blood cell (RBC) GSH-Pxs activity in patients with different stages of CKD.Patients and Methods:In this randomized clinical trial, forty-five patients with CKD who attended in a nephrology clinic were recruited. The patients were randomly allocated into three groups according to their creatinine clearance rate and were supplemented with daily Se 200 mcg for three months. Plasma Se concentration and RBC GSH-Pxs activity were measured in each patient at the beginning and at the end of the study. This clinical trial was registered in the Iranian Registry of Clinical Trials (www.irct.ir) with registration number ID of IRCT201305318501N2.Results:Plasma Se concentration and RBC GSH-Pxs activity increased significantly in all three groups of patients with CKD (P < 0.05). There were no significant differences between three groups regarding baseline plasma Se (P = 0.268) and RBC GSH-Pxs activity (P = 0.741).Conclusions:Se supplementation can increase plasma Se concentration and RBC GSH-Pxs activity in patients with different stages of CKD.

Plasma and breast-milk selenium in HIV-infected Malawian mothers are positively associated with infant selenium status but are not associated with maternal supplementation: results of the Breastfeeding, Antiretrovirals, and Nutrition study

Selenium is found in soils and is essential for human antioxidant defense and immune function. In Malawi, low soil selenium and dietary intakes coupled with low plasma selenium concentrations in HIV infection could have negative consequences for the health of HIV-infected mothers and their exclusively breastfed infants. We tested the effects of lipid-based nutrient supplements (LNS) that contained 1.3 times the Recommended Dietary Allowance of sodium selenite and antiretroviral drugs (ARV) on maternal plasma and breast-milk selenium concentrations. HIV-infected Malawian mothers in the Breastfeeding, Antiretrovirals, and Nutrition study were randomly assigned at delivery to receive: LNS, ARV, LNS and ARV, or a control. In a subsample of 526 mothers and their uninfected infants, we measured plasma and breast-milk selenium concentrations at 2 or 6 (depending on the availability of infant samples) and 24 wk postpartum. Overall, mean (± SD) maternal (range: 81.2 ± 20.4 to 86.2 ± 19.9 μg/L) and infant (55.6 ± 16.3 to 61.0 ± 15.4 μg/L) plasma selenium concentrations increased, whereas breast-milk selenium concentrations declined (14.3 ± 11.5 to 9.8 ± 7.3 μg/L) from 2 or 6 to 24 wk postpartum (all P < 0.001). Compared with the highest baseline selenium tertile, low and middle tertiles were positively associated with a change in maternal plasma or breast-milk selenium from 2 or 6 to 24 wk postpartum (both P < 0.001). With the use of linear regression, we showed that LNS that contained selenium and ARV were not associated with changes in maternal plasma and breast-milk selenium, but maternal selenium concentrations were positively associated with infant plasma selenium at 2 or 6 and 24 wk postpartum (P < 0.001) regardless of the study arm. Selenite supplementation of HIV-infected Malawian women was not associated with a change in their plasma or breast-milk selenium concentrations. Future research should examine effects of more readily incorporated forms of selenium (ie, selenomethionine) in HIV-infected breastfeeding women.

Effect of injectable sodium selenite on the level of stress biomarkers in male aardi goats

The aim of the present study was to evaluate the effects of sodium selenite (SS) injection on plasma concentrations of selenium (Se), glutathione peroxidase (GSH-Px); Malondialdehyde (MDA), and cortisol. A total of twenty seven male Aardi goats were randomly divided into three equal groups; group I (control, fed selenium deficient diet), II (injected with 0.01 mg SS/kg body weight) and III (injected with 0.05 mg SS/kg body weight). Plasma selenium levels differed significantly between treatment and control groups from week one to week three. Level of GSH-Px also differed significantly between the groups. Cortisol varied according to selenium supplementation in week one, two and three. Sodium selenite injection significantly increased Se levels in plasma of Aardi goats as compared with the control group. In conclusion, sodium selenite treatment to Aardi goats minimized the stress level in male Aardi goats, and it was difficult from the experimental design to recommend one of the two doses as therapeutic or preventive anti stress protocols.

Low plasma selenium concentrations in critically ill children: the interaction effect between inflammation and selenium deficiency.

IntroductionLow plasma selenium concentrations are frequent in critically ill patients. However, whether this is due to systemic inflammation, a deficient nutritional state or both is still not clear. We aimed to determine the factors associated with low plasma selenium in critically ill children while considering the inflammatory response and nutritional status.MethodA prospective study was conducted in 173 children (median age 34 months) with systemic inflammatory response who had plasma selenium concentrations assessed 48 hours after admission and on the 5th day of ICU stay. The normal reference range was 0.58 μmol/L to 1.6 μmol/L. The outcome variable was ‘low plasma selenium’, which was defined as plasma selenium values below the distribution median during this period. The main explanatory variables were age, malnutrition, sepsis, C-reactive protein (CRP), and clinical severity scores. The data were analyzed using a Binomial Generalized Estimating Equations model, which includes the correlation between admission and 5th day responses.ResultsMalnutrition and CRP were associated with low plasma selenium. The interaction effect between these two variables was significant. When CRP values were less than or equal to 40 mg/L, malnutrition was associated with low plasma selenium levels (odds ratio (OR) = 3.25, 95% confidence interval (CI) 1.39 to 7.63, P = 0.007; OR = 2.98, 95% CI 1.26 to 7.06, P = 0.013; OR = 2.49, 95% CI 1.01 to 6.17, P = 0.049, for CRP = 10, 20 and 40 mg/L, respectively). This effect decreased as CRP concentrations increased and there was loose significance when CRP values were >40 mg/L. Similarly, the effect of CRP on low plasma selenium was significant for well-nourished patients (OR = 1.13; 95% CI 1.06 to 1.22, P <0.001) but not for the malnourished (OR = 1.03; 95% CI 0.99 to 1.08, P = 0.16).ConclusionsThere is a significant interaction between the magnitude of the inflammatory response and malnutrition on low plasma selenium. This interaction should be considered when interpreting plasma concentrations as an index of selenium status in patients with systemic inflammation as well as in the decision on selenium supplementation.

Falsely elevated plasma selenium due to gadolinium contrast interference: a novel solution to a pre-analytical problem

Aims/Background Trace elements are commonly measured by inductively coupled mass spectrometry (ICP-MS). A 33-year-old male had a reduced plasma zinc on ICP-MS of 8.5 μmol/L (reference interval 10-17). Plasma selenium (Se) concentration was incidentally found to be 66 μmol/L (reference interval 0.45-1.4), a potentially lethal level, despite not taking selenium supplements, no occupational exposure and no toxicity symptoms. He had earlier undergone magnetic resonance imaging (MRI) with gadolinium (Gd) contrast which is known to interfere with Se on ICP-MS (as the mass to charge ratio of Gd2+ with atomic weight 156 is the same as two Se+ with atomic weight 78). We aimed to adjust our method to prevent this pre-analytical interference. Methods Selenium is measured on an Agilent 7700 (by monitoring Se-78 isotope), which we modified to also include the Se-82 isotope. Results Plasma Se results (n = 40) derived from monitoring the two different Se isotopes gave similar results with a good correlation (R = 0.99). On repeat analysis, our patient had Se concentration of 65 μmol/L with the Se-78 isotope but only 1.43 μmol/L using Se-82. Gd-156 isotope was also elevated. Conclusion To avoid misleading Se results, we suggest that plasma Se analysis by ICP-MS should include a second Se isotope that is not subject to this interference.

Assessment of plasma and red cell trace element concentrations, disease severity, and outcome in patients with critical illness

PurposeThe purpose of the study is to examine the value of both plasma and red cell trace element measurements when assessing nutritional status in patients with critical illness. Materials and MethodsA total of 125 patients who were admitted to intensive care unit with evidence of systemic inflammatory response as per Bone's criteria were recruited. Venous blood samples were obtained from all on admission and, in 31 of the 125 patients, on approximately days 4 and 7. Copper, zinc, and selenium concentrations were measured in plasma and erythrocytes and results related to mortality and patient outcome measures. ResultsA total of 125 critically ill patients were recruited; 81 (66%) were male, the median age was 60 (range, 18-100), and the medical/surgical proportion was 55/70 (44%/56%). The median (lower and upper 2.5th percentile) Acute Physiology and Chronic Health Evaluation II score, Sequential Organ Failure Assessment score, and length of stay and mortality were 21 (16-26), 7 (4-9) 3.7 days (1.5-11.1) and 19%, respectively. Plasma zinc and selenium concentrations were significantly lower on admission compared with reference intervals, whereas copper was increased. Normal plasma glutathione peroxidase activity suggested selenium status was adequate on admission; erythrocyte concentrations of glutathione peroxidase and trace elements were normal, suggesting adequate nutritional status 1 to 2 months before admission. Only plasma zinc and selenium were inversely associated with C-reactive protein (rs = −0.266, P = .004, rs = −0.322, P < .001, respectively). Compared with survivors, albumin (P < .001) concentrations were significantly lower in the nonsurvivor group. No significant difference of plasma selenium and zinc between survivors and nonsurvivors was found, although plasma selenium concentrations tended to be lower (P = .04). On multivariate logistic regression analysis of the significant variables, none was independently associated with mortality. ConclusionThe altered plasma concentrations of zinc, selenium, and copper in patients with critical illness were primarily due to the effects of the systemic inflammatory response and do not reliably indicate their status.

Selenium: its antioxidant effects and issues in selenium supply

The author first summarizes briefly the antioxidant effects attributed to selenium. Literature data on the selenium supply in Hungary are reviewed in detail, also noting some important international reports. Hungarian soils are selenium deficient and this is reflected partly in selenium content of the plants, too. Selenium supplementation has been generally applied to most livestock since the 1980s in Hungary in order to prevent diseases associated with selenium deficiency. There are little data on the selenium content of Hungarian foodstuffs; therefore, selenium content of important foodstuffs available in the European Union is reviewed in detail. Data on selenium concentrations in human plasma or serum are scarce, and the results depend substantially on the analytical methods applied. In conclusion, Hungary is a country with marginal selenium deficiency, and this may play a role in the pathogenesis and poor treatment results of several diseases.

English

&nbsp; The soil contents of trace elements selenium, chromium and manganese were measured to determine&nbsp; their impact on the plasma levels of 160 healthy adult Nigerians in five different experimental locations&nbsp; in Cross River and Akwa Ibom States, South - South Nigeria. The mean (&plusmn;SD) soil selenium, chromium&nbsp; and manganese concentrations were 2.86 &plusmn; 3.97, 15.93 &plusmn; 3.35 and 90.33&plusmn; 42.65 mg/kg, respectively.&nbsp; Manganese soil concentration was the highest and selenium soil concentration was the lowest in all the&nbsp; locations. The mean (&plusmn;SD) plasma selenium, chromium and manganese concentrations were 0.006,&nbsp; 0.111 &plusmn; 0.031 and 0.028 &plusmn; 0.024 mg /1, respectively. There were no significant differences between the&nbsp; concentrations of the trace elements in the soil and the plasma levels as determined by t-test. Plasma&nbsp; levels of chromium and manganese according to the study were adequate but that of selenium was low.&nbsp; &nbsp; Key words: Healthy adult Nigerians, trace elements, plasma level, soil content.

Zinc Supplementation Alters Plasma Aluminum and Selenium Status of Patients Undergoing Dialysis: A Pilot Study

End stage renal disease patients undergoing long-term dialysis are at risk for abnormal concentrations of certain essential and non-essential trace metals and high oxidative stress. We evaluated the effects of zinc (Zn) supplementation on plasma aluminum (Al) and selenium (Se) concentrations and oxidative stress in chronic dialysis patients. Zn-deficient patients receiving continuous ambulatory peritoneal dialysis or hemodialysis were divided into two groups according to plasma Al concentrations (HA group, Al > 50 μg/L; and MA group, Al > 30 to ≤ 50 μg/L). All patients received daily oral Zn supplements for two months. Age- and gender-matched healthy individuals did not receive Zn supplement. Clinical variables were assessed before, at one month, and after the supplementation period. Compared with healthy subjects, patients had significantly lower baseline plasma Se concentrations and higher oxidative stress status. After two-month Zn treatment, these patients had higher plasma Zn and Se concentrations, reduced plasma Al concentrations and oxidative stress. Furthermore, increased plasma Zn concentrations were related to the concentrations of Al, Se, oxidative product malondialdehyde (MDA), and antioxidant enzyme superoxide dismutase activities. In conclusion, Zn supplementation ameliorates abnormally high plasma Al concentrations and oxidative stress and improves Se status in long-term dialysis patients.

A Prospective Study of Selenium Concentration and Risk of Preeclampsia in Pregnant Iranian Women: a Nested Case–Control Study

Preeclampsia remains a leading cause of maternal and perinatal mortality and morbidity worldwide; however, its specific etiology still remains obscure. Some studies implicate poor maternal selenium status predisposing the mother to preeclampsia. This study was designed to determine changes in plasma selenium levels in women having preeclampsia as compared with those with normal pregnancy. In a nested case-control study, 650 normal primigravida in their first 24-28 weeks participated in the study. After 3 months of follow-up of all subjects, blood selenium levels were measured in 38 women presenting consecutively with preeclampsia and in 38 women having a normal pregnancy by atomic absorption spectrophotometry. Birth outcomes were recorded, such as gestational age at delivery, height, weight, birth head circumflex and 1-min Apgar score. Preeclampsia affects about 5.84 % of pregnancies, and in our study, there were no significant differences in age, anthropometric indices, and family history of preeclampsia between the preeclamptic and control groups. The selenium concentrations in plasma in women with preeclampsia were significantly lower as compared with those in women with normal pregnancy (70.63 ± 21.41 versus 82.03 ± 15.54 μg/L, p < 0.05). Being in the bottom tertile of selenium concentration (less than 62.2 μg/L) was associated with greater risk of preeclampsia in pregnant women. The reduced selenium in the maternal circulations observed in the preeclamptic mothers support the hypothesis that insufficient selenium concentration may be a contributing factor to the pathophysiological mechanisms associated with preeclampsia, and optimizing the dietary selenium intake through supplementation could produce demonstrable clinical benefits.

Erythrocyte selenium concentration as a marker of selenium status

Plasma selenium concentration and glutathione peroxidase (GPx) activity are commonly used as markers of selenium nutritional status. However, plasma selenium concentrations fall independently of selenium status during the acute phase response and GPx is analytically problematic. The assay for erythrocyte selenium is robust and concentrations are unaffected by the systemic inflammatory response. This study was performed to investigate the validity of erythrocyte selenium measurement in assessing selenium status. C-reactive protein (CRP), plasma and erythrocyte selenium concentrations and GPx activity were measured in 96 women from two regions of Malawi with low and high selenium dietary intakes. CRP and plasma and erythrocyte selenium was measured in 91 critically ill patients with a systemic inflammatory response. The median CRP value of all subjects from Malawi was 4.2mg/L indicating no inflammation. The median CRP value for the critically ill patients was 126mg/L indicating this group was inflamed. In the non-inflamed population there was a strong positive correlation (r=0.95) between erythrocyte and plasma selenium and a strong positive correlation (r=0.77) between erythrocyte selenium and erythrocyte GPx up to 6.10nmol/g Hb after which maximal activity was reached. In the inflamed population, plasma selenium was low, erythrocyte selenium was normal and there was a weak correlation (r=0.30) between selenium concentrations in plasma and erythrocytes. This demonstrates that plasma selenium is affected by the inflammatory response while erythrocyte selenium concentration is unaffected and can be used to reliably assess selenium status across a wide range of selenium intakes.

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.

Influence of the glutathione peroxidase 1 Pro200Leu polymorphism on the response of glutathione peroxidase activity to selenium supplementation: a randomized controlled trial

A genetic variant at codon 200 (Pro200Leu) of the gene encoding for glutathione peroxidase 1 (GPx1), a selenium-dependent enzyme, is associated with lower enzyme activity; however, the evidence is limited to in vitro and observational studies. The objective was to determine whether the GPx1 Pro200Leu genetic variants modify the response of whole-blood glutathione peroxidase (GPx) activity to selenium supplementation in patients with coronary artery disease in New Zealand. The results from 2 parallel-design, double-blind trials were combined. Participants were randomly assigned to receive a daily supplement of 100 μg Se as l-selenomethionine (n = 129) or placebo (n = 126) for 12 wk. Plasma selenium and whole-blood GPx activity were measured at baseline and at week 12. Participants were genotyped for the GPx1 Pro200Leu polymorphism. Selenium supplementation increased whole-blood GPx activity by 5 (95% CI: 4, 7) U/g hemoglobin (P < 0.001); however, the magnitude of the increase did not differ by genotype (P = 0.165 for treatment-by-genotype interaction). In an exploratory analysis, a significant nutrient-gene interaction was apparent when baseline plasma selenium concentrations were included in the regression model (P = 0.006 for treatment-by-genotype × baseline selenium concentration interaction). Increases in GPx activity were 2-fold higher in Pro homozygotes than in participants carrying a Leu allele when baseline selenium concentrations were ≤1.15 μmol/L (P < 0.05). These results indicate that GPx1 Pro200Leu variants do not substantially modify the response of whole-blood GPx to selenium supplementation in individuals with relatively high plasma selenium concentrations. A nutrient-gene interaction was observed when the baseline selenium concentration was low, but this requires independent confirmation. This trial was registered at www.actr.org.au as ACTRN12605000412639 and ACTRN12606000197538.

A Randomized Trial of Selenium Supplementation and Risk of Type-2 Diabetes, as Assessed by Plasma Adiponectin

BackgroundEvidence that selenium affects the risk of type-2 diabetes is conflicting, with observational studies and a few randomized trials showing both lower and higher risk linked to the level of selenium intake and status. We investigated the effect of selenium supplementation on the risk of type-2 diabetes in a population of relatively low selenium status as part of the UK PRECISE (PREvention of Cancer by Intervention with SElenium) pilot study. Plasma adiponectin concentration, a recognised independent predictor of type-2 diabetes risk and known to be correlated with circulating selenoprotein P, was the biomarker chosen.MethodsIn a randomized, double-blind, placebo-controlled trial, five hundred and one elderly volunteers were randomly assigned to a six-month intervention with 100, 200 or 300 µg selenium/d as high-selenium or placebo yeast. Adiponectin concentration was measured by ELISA at baseline and after six months of treatment in 473 participants with one or both plasma samples available.ResultsMean (SD) plasma selenium concentration was 88.5 ng/g (19.1) at baseline and increased significantly in the selenium-treatment groups. In baseline cross-sectional analyses, the fully adjusted geometric mean of plasma adiponectin was 14% lower (95% CI, 0–27%) in the highest than in the lowest quartile of plasma selenium (P for linear trend = 0.04). In analyses across randomized groups, however, selenium supplementation had no effect on adiponectin levels after six months of treatment (P = 0.96).Conclusions These findings are reassuring as they did not show a diabetogenic effect of a six-month supplementation with selenium in this sample of elderly individuals of relatively low selenium status.Trial RegistrationControlled-Trials.com ISRCTN25193534

PP027-SUN BIOMARKERS OF SELENIUM STATUS IN CRITICALLY ILL PATIENTS

Rationale: Deficient status in selenium, a cofactor of the antioxidant enzyme glutathione peroxidase (GPx), together with hypercatabolic state, can affect the clinical course during the patient’s stay in the intensive care unit (ICU). The resulting increase in oxidative stress has been recognized as a central mechanism in the pathophysiology of critical illnesses, particularly the appearance of multiorgan failure. Methods: A blood sample was obtained on the day of admission in the ICU from 65 critically ill patients in Granada province (southern Spain) who fulfilled the inclusion criteria. Selenium was measured with inductively coupled plasma mass spectrometry (ICP-MS). GPx was measured indirectly as enzyme activity (reduction of organic peroxides by c-GPx), and selenoprotein P was measured by SEPP1 enzyme-linked immunoassay. Results: On admission to the ICU, GPx enzyme activity was below the reference value ( 24 U/mL). Mean plasma concentration of selenium was 56±12.9mg/dL, and on the day of admission 67.7% of the patients were selenium deficient. By day 7 of their ICU stay this proportion had increased significantly to 100% (p < 0.05). Below-normal values of SEPP1 (<3.43 mg/L) were found in 77.3% of the patients on the day of admission, and this proportion had increased to 100% by the end of their ICU stay. Conclusion: During their ICU stay, antioxidant GPx enzyme activity increased and plasma concentration of selenium decreased in the patients we studied. This selenium deficiency can lead to increased stress and increased demands on endogenous antioxidant synthesis. Selenium intake should be monitored in order to ensure optimum antioxidant response and palliate the adverse effects of this nutritional deficiency.

Maternal selenium, copper and zinc concentrations in pregnancy associated with small-for-gestational-age infants.

Pregnancy during adolescence increases the risk of adverse pregnancy outcome, especially small-for-gestational-age (SGA) birth, which has been linked to micronutrient deficiencies. Smoking has been shown to be related to lower micronutrient concentrations. Different ethnicities have not been examined. We used a subset from a prospective observational study, the About Teenage Eating study consisting of 126 pregnant adolescents (14-18-year-olds) between 28 and 32 weeks gestation. Micronutrient status was assessed by inductively coupled mass spectrometry. Smoking was assessed by self-report and plasma cotinine, and SGA was defined as infants born <10th corrected birthweight centile. The main outcome measures were as follows: (1) maternal plasma selenium, copper and zinc concentrations in adolescent mothers giving birth to SGA vs. appropriate-for-gestational-age (AGA) infants; and (2) comparison of micronutrient concentrations between women of different ethnicities and smoking habits. The plasma selenium {mean ± standard deviation (SD) [95% confidence interval (CI)]} concentration was lower in the SGA [n = 19: 49.4 ± 7.3 (CI: 45.9, 52.9) µg L(-1)] compared with the AGA [n = 107: 65.1 ± 12.5 (CI: 62.7, 67.5) µg L(-1); P < 0.0001] group. Smoking mothers had a lower selenium concentration compared with non-smokers (P = 0.01) and Afro-Caribbean women had higher selenium concentrations compared with White Europeans (P = 0.02). Neither copper nor zinc concentrations varied between groups. Low plasma selenium concentration in adolescent mothers could contribute to the risk of delivering an SGA infant, possibly through lowering placental antioxidant defence, thus directly affecting fetal growth. Differences in plasma selenium between ethnicities may relate to variation in nutritional intake, requiring further investigation.

A Case-Control Study of the Risk of Cutaneous Melanoma Associated with Three Selenium Exposure Indicators

A direct association between exposure to the metalloid selenium and risk of cutaneous melanoma has been suggested by some observational and experimental cohort studies, whereas other studies have yielded inconsistent results. Since some of the inconsistencies may be due to exposure misclassification arising from the use of exposure indicators that do not adequately reflect body tissue selenium content or the levels of the biologically relevant species of this metalloid, we examined this issue using multiple indicators of exposure. We analyzed the relation of selenium exposure with risk of cutaneous melanoma using two different biomarkers, plasma and toenail selenium concentration, and estimated dietary selenium intake in a population-based case-control series (54 cases, 56 controls) from an Italian community. In unmatched and matched logistic regression models as well as nonparametric generalized additive models, higher plasma selenium levels were strongly associated with excess disease risk. In contrast, toenail and dietary selenium exhibited little relation with melanoma risk. The pattern of correlation among indicators of exposure differed by disease status, with dietary intake associated with plasma selenium levels in patients but not in controls. Our data showed that different selenium exposure indicators can yield different inferences about melanoma risk. Although the series was small, our results are consistent with a positive association between circulating levels of selenium and melanoma risk. Further investigation of the exposure classification performance of various selenium biomarkers and of metabolic patterns of the metalloid and of its speciation are needed to help elucidate the relation between selenium exposure and human health.

Serum levels of selenium in patients with brain metastases from non-small cell lung cancer before and after radiotherapy

PurposeThis study was to evaluate the influence of radiotherapy on the selenium serum levels of non-small cell cancer patients with brain metastases. Patients and methodsThis prospective study included 95 non-small cell cancer patients with brain metastases treated by radiotherapy from December 2007 until November 2010. Plasma selenium levels were determined before and at the end of the radiotherapy. Age, body mass index (BMI), prior chemotherapy, pathological type and personal habits (smoking and alcoholism) were recorded for each patient. ResultsThe mean age was 63 years; the mean BMI was 27.6. Seventy-six patients (80%) were non-smokers. Sixty-two patients (65.3%) showed no drinking habits and 8 (8.4%) have no prior chemotherapy. Thirty-nine patients (41.1%) were adenocarcinoma, 51 (53.7%) were squamous cell carcinoma and five (5.3%) were large cell carcinoma. At the beginning of radiotherapy, the mean selenium level for all patients was 90.4μg/l and after radiation this value dropped to56.3μg/l. Multivariate analysis showed statistically significant difference in the plasma selenium concentration before and after radiotherapy for age (P<0.001), BMI (P<0.001), smoking (P<0.001), alcoholism (P<0.001), prior chemotherapy (P<0.001) and pathological type (P<0.001). ConclusionSignificant reduction in plasma levels of selenium was recorded in patients undergoing radiotherapy, suggesting attention to the nutritional status of this micronutrient and other antioxidant agents.

BASELINE HEALTH PARAMETERS AND SPECIES COMPARISONS AMONG FREE-RANGING ATLANTIC SHARPNOSE (RHIZOPRIONODON TERRAENOVAE), BONNETHEAD (SPHYRNA TIBURO), AND SPINY DOGFISH (SQUALUS ACANTHIAS) SHARKS IN GEORGIA, FLORIDA, AND WASHINGTON, USA

Sharks are of commercial, research, conservation, and exhibition importance but we know little regarding health parameters and population status for many species. Here we present health indicators and species comparisons for adults of three common wild-caught species: 30 Atlantic sharpnose sharks (Rhizoprionodon terraenovae) and 31 bonnethead sharks (Sphyrna tiburo) from the western Atlantic, and 30 spiny dogfish sharks (Squalus acanthias) from the eastern Pacific. All animals were captured during June-July 2009 and 2010. Median values and preliminary reference intervals were calculated for hematology, plasma biochemistry, trace nutrients, and vitamin A, E, and D concentrations. Significant differences, attributable to physiologic differences among the species, were found in the basic hematologic and plasma biochemistry variables. Significant species differences in arsenic and selenium plasma concentrations were found and appear to coincide with diet and habitat variability among these three species. Vitamin E was significantly higher in the bonnethead shark, again related to the foraging ecology and ingestion of plant material by this species. The Atlantic sharpnose had significantly higher vitamin A concentrations, supported by the higher proportion of teleosts in the diet. Vitamin D was below the limit of quantification in all three species. These preliminary reference intervals for health variables can be used to assess and monitor the population health and serve as indicators of nutritional status in these populations of wild elasmobranchs.