The renal excretion of selenium.

The excretion of selenium in urine was determined in West German healthy volunteers. Women excrete 17.7 +/- 4.2 micrograms Se/d and men 19.0 +/- 9.0 micrograms Se/d. The daily selenium excretion per gram creatinine is 13.5 +/- 3.8 micrograms Se/g crea for women and 9.8 +/- 3.3 micrograms Se/g crea for men. The clearance of selenium from the plasma is calculated with 0.18 mL/min. The selenium excretion per day is positively correlated with the 24 h excretion of urea and creatinine. The correlation of the selenium excretion with the urea excretion is most probably owing to the fact that the selenium intake of West Germans is linked primarily to foods with high protein contents. That the selenium excretion is directly correlated with the creatinine excretion is an indicator that the muscle, which accounts for nearly 50% of the whole body selenium in West German adults, influences the selenium excretion in urine. The positive correlation of the selenium excretion with the potassium excretion also indicates that the muscle mass contributes significantly to the selenium excretion in urine. Another indicator that the selenium excretion is influenced by the muscle is that after intensive muscular activity (running), selenium excretion is enhanced. The 24 h selenium excretion is dependent on the glomerular filtration rate of the kidney characterized by the creatinine clearance. This result is important, because if the selenium excretion is used as parameter for the selenium status of humans, the kidney function should be known. This is a limitation for the use of the urinary selenium excretion as parameter for the selenium status. This is especially important for patients whose glomerular filtration rate is low. The 24 h selenium excretion is further influenced by the 24 h urine volume. Selenium losses via urine may be concomitant with protein losses in urine.     

Correlations of blood selenium with hematological parameters in West German Adults

The serum selenium and the whole blood selenium of 72 healthy persons (47 women, 25 men) was determined. There exist sex specific differences of the whole blood selenium between men (98±19 μg Se/L) and women (89±17 μg Se/L). The serum selenium did not show sex specific differences, but sex specific differences are found if the total amount of extracellular selenium is calculated by correction of the serum selenium with the hematocrit. Women have more extracellular selenium/L whole blood (40±8 μg Se) than men (36±7 μg Se). Men have more intraerythrocyte selenium (cellular selenium=67±14 μg Se) in one L whole blood than women (52±17 μg Se). There exist also sex specific differences if the cellular selenium is calculated/g hemoglobin (men .44 μg Se/g Hb, women .37 μg Se/Hb) or per erythrocyte (men 136.1×10^?19 g Se/Ery, women 113.9×10^?19 g Se/Ery). In the cellular compartment of one L whole blood on the average 1.56 times more selenium is present than in the extracellular compartment. Most of the intraerythrocyte selenium is hemoglobin bound (84%) and utmost 16% glutathione peroxidase associated. An erythrocyte contains about 3500 mol glutathione peroxidase, or, for every 80000 mol hemoglobin one mol glutathione peroxidase. A standard man needs about 2.5 μg selenium/d for the synthesis of the hemoglobin and the erythrocyte. The hematological parameters hemoglobin and the erythrocyte number are correlated with the cellular selenium and the ratio cellular selenium/extracellular selenium. Positive significant correlations are found that are best if a parabolic model is used to interpret the shape of the curves. From the shape of the best correlation lines it can be concluded that selenium may be beneficial for hemoglobin synthesis and erythropoesis. The extracellular selenium may have influence on the volume of the erythrocyte by protecting the outer erythrocyte membrane from lipid peroxidation. A method is reported based on the carbon furnace atomic absorption spectroscopy, which is able to determine without wet digestion selenium in whole blood.     

The organ distribution of selenium in German adults

The selenium concentrations were determined in liver, kidney, skeletal muscle, heart, brain, prostate, testis, bile, lung, and spleen of German traffic accident victims. In addition the nitrogen and phosphorus contents were determined in the same organs and tissues. On a per-weight unit basis, the highest selenium concentration was found in kidney. However, this corresponds to only 4% of the total body selenium. Most of the whole body selenium (50%) is present in skeletal muscle, which thus appears to act as a selenium storage organ. However, there is also evidence that selenium is required for muscle function. In plasma and interstitial fluid, .450 mg of Se, or 7.5% of the total body selenium is present. A comparison of the organ Se concentrations of the German traffic accident victims with the selenium concentrations of the same human organs as reported in different countries indicates that the organ concentrations of West Germans are comparable to that of the population of New Zealand, a low-Se country, and significantly lower than that observed in the organs of American, Canadian, and especially Japanese subjects. The international comparison of the organ selenium concentrations also revealed that the selenium uptake of kidney is higher at low- and adequate dietary Se intakes and lower if the dietary Se supply is high, as is the case for Japanese subjects. Estimates of the daily excretion of selenium with the bile indicate that the amounts are three times higher than the daily urinary losses and in the same order of magnitude as the daily dietary selenium intakes. Enterohepatic reabsorption of selenium from the bile appears to be a significant mechanism of conserving dietary selenium and to maintain Se balance at comparatively low dietary Se intakes.     

Characterization of selenium status of inhabitants in the region Ústi nad orlici,czech republic by inaa of blood serum and hair and fluorimetric analysis of urine

Selenium is an essential trace element and its isufficient status may cause serious health complications for both individuals and the whole populations. To investigate the selenium status of the subpop-ulation in northeastern Bohemia represented by the region ústí nad Orlicí, 253 serum, 469 urine, and 31 hair samples from 470 randomly selected volunteers between 6 and 65 yr of age have been analyzed for selenium concentration. Serum and hair Se were detected by instrumental neutron activation analysis (means: 55 ±11 Μg Se/L sera, 0.268 ±0.040 Μg Se/g hair). Urine Se was measured by fluorimetry (12 ±5 Μg Se/L urine) with coanalyses of Lyphocheck urine, SRM Urine 2670, and Seronorm urine for quality control of the method. Results proved significant age-dependent differences, but gender differences were not significant. The frequency plot of serum Se proved maximal frequencies in adults between 55 and 70 Μg Se/L and in children in the range 45–55 Μg Se/L. The same plots of urine Se for both age groups showed maximal frequency in the limits 8–15 Μg Se/L. All indices used (Se in serum, urine, and hair) confirmed mild to severe selenium deficiency in the population of the region.     

Human urinary excretion and metabolism of (82)Se-enriched selenite and selenate determined by LC-ICP-MS

Urinary excretion of selenium after ingestion of isotope labeled selenite and selenate was studied in seven healthy volunteers, 4 men and 3 women (age 28-50 years). An aqueous solution containing 330 μL (82)Se-selenate (corresponding to 74.3 μg (82)Se) was given orally and urine samples were subsequently collected during the following 24 hours. The scheme was repeated four weeks later with a 280 μL (82)Se-selenite solution (corresponding to 74.4 μg (82)Se). The amount of total Se in the urine samples was determined by inductively coupled mass spectrometry. The mean total urinary excretion of (82)Se following (82)Se-selenate administration was 33.7% (range 15.6-42.5%) while the mean total excretion of (82)Se after (82)Se-selenite administration was 3.2% (range 2.8-3.9%) of the ingested amount. LC-ICPMS analysis of the urine samples showed that the majority of the selenium excreted after selenate ingestion was unchanged selenate for 6 of the individuals while one individual had metabolized a fraction (approx. 20%) of the selenate to selenosugar. Ingestion of 10 times larger doses of selenite in two individuals resulted in 13-23% excretion primarily excreted as selenosugar. These results show that the human metabolic pathways of selenite and selenate are different and indicate that not all selenate, although well absorbed, may be available for the beneficial health effects.     

Selenium concentration in human urine

In this work we have determined selenium concentration in urine in two groups of healthy subjects. Selenium content in the younger group, aged 11-15 years (n = 41), was 13.7 +/- 6.5 micrograms/g-1 creatinine. In the older group, aged 17-97 years (n = 62), slightly but statistically significant lower selenium concentration in urine (11.4 +/- 4.9 micrograms/g Ct, p less than 0.05) was found. We have also shown a significant difference in the excretion of the element between the group of boys and men (p less than 0.05). Concentration of selenium excreted in urine in the population of healthy people (11-97 years, n = 103) is 12.3 +/- 5.4 micrograms Se/g Ct.     

Chromium intake and urinary chromium excretion of trauma patients

Glucose metabolism is altered after trauma and those factors that affect glucose metabolism often affect chromium (Cr) metabolism and excretion. To ascertain whether urinary Cr excretion is affected by the elevated serum glucose and other factors associated with trauma, the serum glucose and urinary Cr and Creatinine (Cre) excretion of seven severely traumatized patients were determined. The Cr concentration of intravenous (IV) fluids administered was determined and approximate Cr intake calculated. For all patients, urinary Cr concentration was high in the initial sample collected within 24 h of admission (10.3 ± 2.5 ng/mL, mean ± SEM) and decreased significantly (P < 0.05) by 42 h (2.0 ±0.6 ng/mL). The mean urinary Cr concentration 42 h following admission was 10 times greater than the urinary Cr concentration of normal, healthy subjects (0.2 ± 0.02 ng/mL). There was no significant change in urinary Cre concentration within 42 h of admission, therefore the ratio of urinary Cr to Cre (ng Cr:mg Cre) also decreased. Serum glucose concentration was elevated at admission (170 ± 18 mg/dL, mean ± SD) and decreased to 145 ± 10 mg/dL by 48 h post-admission. The intravenous fluids, dextrose and NaCl, were the lowest in Cr of the samples tested, range 0.02 to 0.20 ng/mL; lactated Ringer’s solution, with or without dextrose, contained 10-20 times more Cr and plasma protein fraction contained approximately 32 ng/mL. The mean calculated Cr intake for the first 24 h postadmission was 37.1 µg/d, significantly greater (P < 0.01) than intake from 24 to 48 h (0.12 µg/d) and 48-72 h (1.63 µg/d). The IV intake of Cr varied for trauma patients depending on fluids required during treatment, but for all patients the relatively high IV Cr intake was rapidly excreted in the urine. These data demonstrate that urinary Cr concentration is elevated several-fold within 24 h of trauma and that Cr contents of intravenous fluids administered in the days immediately following injury vary dramatically. The effects of trauma alone on Cr excretion are difficult to assess because of the variable intake of Cr from IV fluids.     

Evaluation of selenium supply and status of inhabitants in three selected rural and urban regions of the Czech Republic

Blood serum selenium of 65 men and hair selenium of 77 men from three regions of the Czech Republic (CR) were analyzed by neutron activation analysis, and 202 samples of urine from the same populations were analyzed for Se by the fluorimetric method to assess selenium status of these regions. Low status (53 μg Se/L of serum and 0.29 μg Se/g lyophilized hair as means) and very low urine selenium (8.7 μg/L urine) were detected. By these data, the CR is among the countries with the lowest Se intake. A comparison of studied regions is presented. Moreover, values of serum zinc were within the reference range, but mild to moderate deficiency in the supply of iodine was detected.     

Relationships among spermatozoal abnormalities and the selenium concentration of blood plasma,semen, and reproductive tissues in young bulls

The concentration of selenium (Se) was measured by instrumental neutron activation analysis in samples of blood plasma, semen, and reproductive and non-reproductive tissues obtained from each of 12 young bulls (8 Angus and 4 Simmental). Semen was collected by electro-ejaculation and used for measurements of the frequency of primary and secondary spermatozoal abnormalities. The mean Se concentration (μg/ml) of semen (± SD) was 0.461 (±0.223) compared to 0.061 (±0.014) for blood plasma. Tissue from the testis, caput epididymis and cauda epididymis had mean Se concentrations of from 2.5 to 2.7 μg/g compared to less than 1.8 μg/g in all other tissues except the pituitary gland (3.4 μg/g) and kidney cortex (6.9 μg/g).Correlations of the proportional incidence of spermatozoal abnormalities with Se concentrations in reproductive tissues, semen or blood plasma were low. Although Se may be concentrated in the testis and epididymis, the Se concentration was not related to spermatozoal abnormalities.     

Urine selenium level in healthy adult population

The level of urine selenium in healthy adult population, 230 persons, was examined. Persons were selected regarding sex, ages, and smoking habits. No differences versus these observations have been found. For a total, group values are 16.96 Se nmol/creatinine mmol, SD=5.44. It is possible from a single-void specimen to express daily excretion of selenium.     

The metabolism of selenomethionine, Se-methylselenocysteine, their selenonium derivatives, and trimethylselenonium in the rat

The formation of dimethylselenide (respiratory) and trimethylselenonium (urinary) metabolites from [75Se]selenomethionine, [75Se]methylselenomethionineselenonium, [75Se]methylselenocysteine, [75Se]dimethylselenocysteineselenonium, and [75Se]trimethylselenonium was determined using single sc doses of 2 or 0.064 mg Se/kg in male and female rats. The 75Se content of liver, kidney, pancreas, testis, spleen, blood, heart, brain, and skeletal muscle was determined at 0.5 and 24 h. Respiratory 75Se after 24 h was greatest from Se-dimethylselenocysteineselenonium (38 and 17% for the high and low doses, respectively). Respiratory 75Se was about 8% for the high dose of Se-methylselenocysteine and was less for all other compounds. Total 75Se excretion in the urine was highest from rats given trimethylselenonium (about 90%, both doses) and was lowest from rats given selenomethionine (4%, low dose). Urine samples were chromatographed on SP-Sephadex cation-exchange columns and 75Se was eluted with ammonium formate; trimethylselenonium was precipitated with ammonium Reineckete solution and trimethylsulfonium carrier. Urinary trimethylselenonium excretion was greatest from rats given trimethylselenonium, but rats given Se-dimethylselenocysteineselenonium (low dose) excreted 35-45% of the dose as trimethylselenonium ion. The lowest quantity of trimethylselenonium was excreted by rats given the low dose of selenomethionine (0-3%). Pancreas, kidney, and liver showed the highest uptake (% of dose/g) of the selenium compounds. Trimethylselenonium was highly concentrated by the kidney and also showed high myocardial uptake (heart/blood ratio = 5) 0.5 h after injection; the selective uptake of trimethylselenonium in heart was not observed for the other selenonium compounds.     

Effect of Selenium Supplementation on Blood Status and Milk,Urine, and Fecal Excretion in Pregnant and Lactating Camel

Ten pregnant female camels divided into two groups received, after a 2-week adaptation period, an oral selenium (Se) supplementation (0 and 2 mg, respectively) under sodium selenite form for 6 months from the three last months of gestation up to the three first months of lactation. Feed intake was assessed daily. Blood samples and body weight were taken on a biweekly basis, both in dams and their camel calves after parturition. Feces and urine samples were collected monthly and milk on a biweekly basis. The Se concentration in serum increased significantly in the supplemented group and was threefold higher than the concentration compared to the control group, respectively, 305.9 ± 103.3 and 109.3 ± 33.1 ng/mL. The selenium concentration increased in similar proportion in milk (86.4 ± 39.1 ng/mL in the control group vs 167.1 ± 97.3 ng/mL in treated group), in urine, and feces. The gluthathione peroxidase (GSH-Px) activity varied between 18.1 ± 8.7 IU/g hemoglobin (Hb) in control group and 47.5 ± 25.6 IU/g Hb in treated group but decreased after parturition in both groups. Vitamin E did not change significantly and was, on average, 1.17 ± 0.72 and 1.14 ± 0.89 ng/mL in the control and treated groups, respectively. Significant correlations were reported between serum Se, milk Se, GSH-Px, and fecal and urinary excretion or concentration. Blood values in camel calves were similar to those of the dams. The results seemed to confirm the sensitivity of camel to Se supplementation with an important increase of selenium in serum and milk.     

Intervention trial with selenium for the prevention of lung cancer among tin miners in Yunnan,China

This pilot study evaluated the feasibility and effectiveness of conducting a double-blind clinical trial for the prevention of lung cancer with selenium (Se) in Yunnan Tin Corporation, the People's Republic of China, where the incidence rates of lung cancer are extraordinarily high among the miners. Forty healthy miners were randomized to either 300 μg of Se in high Se malt cakes or an identical placebo of malt cakes daily for one year. Subjects consumed their usual daily diet. The low Se concentrations in plasma (0.05±0.008 μg/mL) and hair (0.442±0.085 μg/g) reflected their low dietary Se intake in the control subjects. In Se-supplemented group, the Se status was increased by 178% for serum and 194.8% for hair. The serum GSHpx activity was increased by 155.7%, whereas the lipid peroxide level was reduced by 74.5% compared to the placebo. The results of UDS assay indicated that the lymphocyte DNA damage induced by ultraviolet irradiation and carcinogen 3,4-benzpyrene could be protected by Se supplementation. Se-supplementation did not affect the liver function test (SGPT), as well as the concentrations of hemoglobin, albumin, and cholesterol. Thus, daily intake of 300 μg Se in form of Se-malt as a chemopreventive measure is safe and effective to humans with low Se status.     

24 h urinary creatinine excretion during pregnancy and its application in appropriate estimation of 24 h urinary iodine excretion

BackgroundUrinary creatinine can be used to adjust urinary iodine to evaluate iodine nutritional status during pregnancy. However, the reference intervals and impact factors of urinary creatinine are unknown.Methods24 h urine creatinine concentration (24 hUCr) and spot UCr at four different time periods of the day of pregnant women from Part 1 (n = 743) were measured. Linear regression analysis was performed to identify the impact factors of 24 h urinary creatinine excretion (24 hUCrE) and obtain the estimated 24 h urinary creatinine excretion (24 hUCrE_est). Then measured urinary iodine concentration (UIC) of 24 h and at fasting of pregnant women from Part 2 (n = 325), used spot urinary iodine to creatinine concentration ratio (UIC/UCr) and 24 hUCrE_est to calculate the estimated 24 h urinary iodine excretion (24 hUIE_est), finally checked the consistency and correlation of 24 hUIE_est and 24 h urinary iodine excretion (24 hUIE).ResultsIn Part 1, the median 24 hUCrE was 1.24(IQR0.98–1.76)g, and the reference interval was 0.61−2.93 g. The median 24 hUCr was 0.76 (IQR0.57−1.01)g/L, and the reference interval was 0.36−1.88 g/L. Multiple linear regression results showed that pregnancy weight was an influencing factor to 24 hUCrE after adjusting by gestational weeks, age, pre-pregnancy BMI, and percentage of body fat (F = 45.029, p＜0.001). In Part 2, there was no statistically significant difference between 24 hUIE_est and 24 hUIE (Z =−0.767, p = 0.443). Using 24hUIE as the gold standard, the relative average difference in 24hUIE_est was 4.2 %, the relative average differences for UIC and UIC/UCr were 32.4 % and 37.2 %. The reference interval of 24 hUIE and 24 hUIE_est were 88.43–585.90 μg and 50.97–700.39 μg, respectively.ConclusionsThe reference intervals of 24 hUCrE, spot UCr, 24 hUIE, and 24 hUIE_est during pregnancy were established. 24 hUCrE has important application value in iodine nutrition evaluation to gain more lead time for pregnant women with iodine nutrition-related diseases.     

Study on the stereoselective excretion of tetrahydropalmatine enantiomers in rats and identification of in vivo metabolites by liquid chromatography‐tandem mass spectrometry

The objective of this work was to study the stereoselectivity in excretion of tetrahydropalmatine (THP) enantiomers by rats and identify the metabolites of racemic THP (rac‐THP) in rat urine. Urine and bile samples were collected at various time intervals after a single oral dose of rac‐THP. The concentrations of THP enantiomers in rat urine and bile were determined using a modification of an achiral–chiral high‐performance liquid chromatographic (HPLC) method that had been previously published. The cumulative urinary excretion over 96 h of (?)‐THP and (+)‐THP was found to be 55.49 ± 36.9 μg and 18.33 ± 9.7 μg, respectively. The cumulative biliary excretion over 24 h of (?)‐THP and (+)‐THP was 19.19 ± 14.6 μg and 12.53 ± 10.4 μg, respectively. The enantiomeric (?/+) concentration ratios of THP changed from 2.80 to 5.15 in urine, and from 1.36 to 1.80 in bile. The mean cumulative amount of (?)‐THP was significantly higher than that of (+)‐THP both in urine and bile samples. However, the enantiomeric (?/+) concentration ratios in rat urine and bile were significantly lower than those ratios in rat plasma. These findings suggested the excretion of THP enantiomers was stereoselective rather than a reflection of chiral pharmacokinetic aspects in plasma and (?)‐THP was preferentially excreted in rat urine and bile. Three O‐demethylation metabolites and the parent drug rac‐THP were detected by liquid chromatography‐tandem mass spectrometry in rat urine. One metabolite was obtained by preparative HPLC and identified as 10‐O‐demethyl‐THP. Chirality, 2010. © 2009 Wiley‐Liss, Inc.     

A simple radioimmunoassay for the measurement of testosterone glucosiduronate in unextracted urine

A simple, reliable and rapid radioimmunoassay (RIA) for the determination of testosterone glucosiduronate (TG) in crude urine is described. Two protein-TG complexes were investigated in raising antibodies: a) Bovine serum albumin (BSA)-TG and b) human plasma Cohn's fraction IV-4 (CF)-TG. In rabbits, high liters of antibodies were obtained after the injection of CF-TG. The specificity of the antiserum was sufficiently high (cross reaction with free testosterone 27%, with 5α-dihydrotestosterone-glucosiduronate 20%). TG was estimated in small aliquots of male and female urine after evaporation overnight at 50° C in order to eliminate interfering material. The intraassay coefficient of varation (CV) was found to be 6% and the interassay CV 11%. TG has been determined in 40 samples of urine simultaneously by “direct” RIA and by a “classical” RIA following hydrolysis with β-glucuronidase. The coefficient of correlation was found to be 0.89. The mean excretion of TG in the urine of 26 healthy men amounted to 164 ± 51 μg/24 hours with a range from 97 to 546 μg/24 hours. In a group of 16 women a mean urinary excretion of TG of 24 ± 10 μg/24 hours was determined. The method allows a technician to assay 40 samples per day.     

Exacerbation of Underlying Hypothyroidism Caused by Proteinuria and Induction of Urinary Thyroxine Loss: Case Report and Subsequent Investigation

ObjectiveTo describe a patient with excess urinary thyroxine (T₄) excretion and worsening of preexisting hypothyroidism in the setting of nephrotic syndrome and to determine whether excess urinary T₄ excretion is present in other patients with proteinuria.MethodsWe present data regarding the patient’s initial presentation, diagnostic studies, and course of her illness. We suspected urinary T₄ loss to be the cause of her presentation and analyzed her urine sample for total T₄. We also analyzed differences in urinary T₄ excretion in 22 patients with proteinuria and 16 control patients without proteinuria. Relevant medical literature is reviewed.ResultsA 44-year-old woman presented with a 3-month history of increasing fluid retention, weight gain, and fatigue. She had long-standing hypothyroidism on a stable levothyroxine dosage, 125 mcg/d. She had gained 27 kg and had developed significant edema. She had a grossly elevated thyroid-stimulating hormone level of 91 mIU/L. Her condition worsened, and a urinary protein measurement was 14.06 g/24 h—diagnostic of nephrotic syndrome. The levothyroxine dosage was increased to 225 mcg/d. Urinary total T₄ concentration in a 24-hour sample was 59.0 μg/L (83.1 μg/24 h), indicating that a substantial fraction of her orally ingested T₄ was lost in urine. Urinary total T₄ excretion was significantly higher in patients with proteinuria (mean ± standard deviation, 18.0 ± 18.2 μg/L) vs control patients without proteinuria (mean, 3.8 ± 1.8 μg/L) (P = .0014).ConclusionIn the patient described, urinary T₄ loss due to proteinuria and nephrotic syndrome resulted in a severe exacerbation of underlying hypothyroidism. (Endocr Pract. 2008;14:97-103)     

STEADY STATE MAINTENANCE OF ELECTROLYTES IN THE SPINAL CORD OF THE FROG

Isolated frog spinal cords equilibrated from 3 to 24 h in Ringer's solution maintained steady state conditions with regard to electrolyte composition. Total sodium and chloride contents measured on the same spinal cords were found to be nearly equivalent (Na = 46.6 ± 1.4μmol/g wet wt vs Cl = 46.2 ± 1.2μmol/g wet wt). Calcium and magnesium contents were 3.0 ± 0.5 and 4.8 ± 0.2pμol/g wet wt respectively for fresh spinal cords and 2.1 ± 0.4 and 5.5 ± 0.9pmol/g wet wt respectively for spinal cords equilibrated for 24 h. Zinc content was 0.29 ± 0.01 μmol/g wet wt. Insulin space was found to be smaller than sucrose space (0.24 ml/g vs 0.37 ml/g). Sodium and chloride spaces were slightly higher than sucrose space. Sodium and chloride in the non-sucrose space was 4.8 and 9.5 μmol/g wet wt. Residual radioactive sodium, or sodium content of spinal cords washed out for 180 min in non-radioactive Ringer's solution or in choline or lithium Ringer's solution, was 4.2 ± 0.4μmol/g wet wt (n = 9). The agreement between residual sodium content and sodium in the non-sucrose space suggests that the mean intracellular sodium content of the spinal cord neurons is low.     

Selenium intake and status of postpartum women and postnatal depression during the first year after childbirth in New Zealand – Mother and Infant Nutrition Investigation (MINI) study

BackgroundSelenium (Se) plays an important role in selenoproteins as an antioxidant, and is involved in thyroid function, mental health and child development. Selenium is low in the local food supplies in NZ. Low selenium intake has been reported in women of childbearing age and postmenopausal women, however, there is little research relating to breastfeeding women and their infants.PurposeThe study investigates maternal and infant selenium intake and status during the first year postpartum, and possible relationships to postnatal depression and anxiety.Basic proceduresThe Mother and Infant Nutrition Investigation (MINI) study is an observational longitudinal cohort study. In total 87 breastfeeding mother-infant pairs were recruited and followed up at 3, 6 and 12 months postpartum. Maternal selenium intake was estimated from a four-day diet diary (4DDD). Selenium concentrations were measured in maternal spot urine, breastmilk and plasma; and infant spot urine samples. Postnatal depression was screened by the Edinburgh Postnatal Depression Scale (EPDS) questionnaire.Main findingsMedian maternal selenium intake was 62 (50, 84) μg/day, with 56 % below the Estimated Average Requirement (EAR) of 65 μg/day. At 3, 6, and 12 months postpartum, median maternal urinary selenium:creatinine ratios were 29.0 (22.4, 42.0), 29.5 (23.1, 28.4), and 30.9 (24.3, 35.3) μg/g; median infant urinary selenium concentrations (IUSC) were 8 (6,13), 11 (6, 15), and 24 (10, 40) μg/L; median breastmilk selenium concentrations (BMSC) were 13 (11, 14), 11 (9, 11) and 12 (11, 13) μg/L; 18 %, 11 % and 14 % of women reported probable minor depression based on the EPDS scores equal or above 10. Estimated median infant selenium intake at 3 and 6 months were 9 (8, 11) and 8 (7, 10) μg/day with 85 % and 93 % below the Adequate Intake of 12 μg/day. Median maternal plasma selenium was 105.8 μg/L at 6 months postpartum. Minor depression at three months postpartum was significantly different across tertiles of plasma selenium concentrations (p = 0.041).Principle conclusionsSuboptimal selenium intake was observed among breastfeeding mothers and their infants in the MINI study. Potentially, some women had insufficient selenium status. Relation between selenium status and risk of postnatal depression and anxiety was inconclusive.Further research is required to explore effects on maternal thyroid function and infant neurodevelopment among women with inadequate selenium intake and status.     

Effect of Selenium Yeast Supplementation on Naturally Acquired Parasitic Infection in Ewes

Gastrointestinal parasites cause substantial economic losses in pasture-based sheep production systems. Supranutritional organic selenium (Se) supplementation may be beneficial because it improves immune responses to pathogens. To evaluate the effect of Se-yeast supplementation on gastrointestinal parasite load, 30 ewes per treatment group were drenched weekly with no Se, 4.9 mg Se/week as Se yeast (maximum FDA-allowed concentration), or supranutritional concentrations of Se yeast (14.7 and 24.5 mg Se/week) starting early fall for 85 weeks. Fecal samples were collected at weeks 63, 66, 78, and 84 and counted for total trichostrongyle-type eggs and Haemonchus contortus eggs (in samples with ≥200 trichostrongyle eggs/g feces). During breeding season (fall), ewes were kept on pasture; ewes receiving 24.5 mg Se/week had lower fecal trichostrongyle egg counts (93?±?40 eggs/g feces) compared with ewes receiving no Se (537?±?257 eggs/g feces; P?=?0.007) or ewes receiving 4.9 mg Se/week as Se yeast (398?±?208 eggs/g feces; P?=?0.03). In winter, fecal trichostrongyle egg counts decreased, and group differences were not apparent. During lambing season (spring), ewes were kept in the barn and fecal trichostrongyle egg counts increased, although no group differences were observed. However, none of the ewes receiving supranutritional Se yeast, and with trichostrongyle egg counts ≥200 eggs/g of feces, but four of the ewes receiving lower Se dosages had H. contortus egg counts ≥1,000 eggs/g feces (P?=?0.04). Our results suggest that supranutritional Se-yeast supplementation may enhance resistance to naturally occurring H. contortus gastrointestinal parasitism in sheep.