A novel method for the purification of selenoprotein P from human plasma.

Selenoprotein P was purified from human plasma using conventional chromatographic methods featuring metal-chelate-affinity chromatography as the final step. Two distinct isoforms with different selenium content were isolated and identified by N-terminal sequencing and immunoblot analysis. Their molecular mass is 61 and 51 kDa, respectively. Both isoforms could be detected in fresh plasma from five individuals. This rules out the possibility of the second isoform being an artifact which results from degradation of full-length selenoprotein P during purification.

Effects of a low selenium state in patients with phenylketonuria.

Eighty-seven participants of the German Collaboratory Study for Children with Phenylketonuria (PKU) presented low plasma, whole blood and hair selenium (Se) values, reduced urinary selenium excretion, and decreased plasma and erythrocyte glutathione peroxidase activity in comparison with a healthy reference group (all figures p < 0.001). Aspartate amino transferase and thyroxine (T4) concentrations in plasma were inversely correlated with the selenium blood values of the PKU children. Somatic measurements showed a negative standard deviation score of body height in the PKU children compared with reference values. Despite the different Se supply, the infants did not present any specific Se deficiency symptoms.

Selenium and glutathione peroxidase activity in Hungarian children.

Selenium (Se) in plasma, whole blood and erythrocytes as well as glutathione peroxidase (GSH-Px) activity in plasma and erythrocytes were investigated in 161 healthy Hungarian children aged 1-15 years. Se was determined by AAS with hydride generation. The estimation of GSH-Px activity was performed in plasma with tertbutyl-hydroperoxide (t-BOOH) and in erythrocytes with hydrogen peroxide (H2O2) as acceptor substrates. The Se content in plasma (0.63 +/- 0.12 mumol/L), whole blood (0.81 +/- 0.14 mumol/L) and erythrocytes (1.14 +/- 0.26 mumol/L, the GSH-Px activity in plasma (87 +/- 19 U/L) and erythrocytes (5.93 +/- 1.04 U/gHb) was low in Hungarian children in comparison to values for children from other European countries. Samples from a rural area in southeast Hungary showed even lower Se content than samples from an industrial city in the northwest or from the capital. The Se in plasma and whole blood as well as GSH-Px activity in the plasma exhibited a clear age dependency. There was a good correlation between plasma Se and GSH-Px activity in all children (r = 0.633, p < 0.001). In addition, in children from the northwestern city and from the capital a correlation was found between Se content and GSH-Px activity of erythrocytes (r = 0.625, p < 0.001). There is no indication that the high mortality in young Hungarian adults from cardiovascular diseases is mainly caused by a low Se supply because there are no corresponding findings in the surrounding countries of southeastern or central eastern Europe with similar low Se states.

Selenium status in infants and children with phenylketonuria and in maternal phenylketonuria.

The selenium status was investigated in 87 patients of the German Collaborative Study of Phenylketonuria (PKU) (mean age 9.7 years). The selenium values and glutathione peroxidase activity in plasma and erythrocytes were negatively correlated to the quality of dietary management (mean plasma phenylalanine value). Despite a low selenium state, the children showed no clinical sign of deficiency and almost all biochemical parameters checked were normal. In the low selenium state thyroxine values are increased and decline during selenium supplementation, whereas tri-iodothyronine and thyroid stimulating hormone levels remain unchanged. The reduction in glutathione peroxidase activity in plasma was more pronounced than in the erythrocytes pointing to a different availability of both enzymes for selenium. In addition we estimated the selenium status in 29 women with PKU during pregnancy. In 32 healthy pregnant women we observed a decrease in plasma selenium values and the glutathione peroxidase activity in the third trimester, whereas the erythrocyte glutathione peroxidase activity remained stable. In contrast to the healthy women we found in the PKU group a steady decrease of all selenium parameters tested during the whole pregnancy. During the long-term low-dose selenium supplementation in PKU children the glutathione peroxidase activity of plasma and erythrocytes increased. They reached a similar plateau after the application of inorganic or organic selenium compounds. In contrast the selenium values of plasma and whole blood showed only a plateau after the application of sodium selenite. The supplementation with low doses of selenium in the form of selenomethionine increased the plasma and whole blood selenium values constantly within the first 9 months. Therefore selenomethionine supplementation cannot be recommended.

Selenium in German infants fed breast milk or different formulas.

At birth and at 4 months of age, selenium (Se) values of 129 term infants on three different diets were determined: 50 infants were breast fed (HM), 44 received formula based on cow's milk (F) and 35 were fed "hypoallergenic formula" (PHF) (partially hydrolysed whey protein). The Se status of a group of twins (n = 12) fed "hypoallergenic formula" was compared with the respective group of singletons. All infants had low plasma Se values during early infancy. The plasma Se of breast-fed infants remained stable (plasma Se 43 +/- 8 ng/ml at birth and at 4 months), whereas plasma glutathione peroxidase (GSH-Px) decreased (birth: 107 +/- 29 U/l; 4 months: 62 +/- 11 U/l). The formula-fed infants showed a reduction in plasma Se levels from birth to 4 months (38 +/- 10 ng/ml and 29 +/- 9 ng/ml, respectively). The decrease was even more pronounced in infants fed the "hypoallergenic formula". This group presented the lowest Se values (plasma Se 39 +/- 9 ng/ml at birth; 20 +/- 6 ng/ml at 4 months). Renal excretion of Se was found to be lower in the formula-fed infants (F and PHF) compared with the HM group. There was a significant correlation between plasma and urinary Se (r = 0.62, p = 0.0001). Urinary Se (microgram Se/g creatinine) appeared to be a good indicator of Se intake. Measurements of urine Se might be used as a screening method for the estimation of the Se supply. Weight and length increases in all infants were within the normal range. There were no differences between the different feeding groups.

Trace mineral status of full-term infants fed human milk, milk-based formula or partially hydrolysed whey protein formula.

Plasma zinc, copper, and selenium concentrations were determined in 129 full-term infants at birth and at the age of four months by electrothermal or hydride generation atomic absorption spectrometry. Of these, 49 infants were exclusively breast-fed (HM), 45 received various commercially available cow's milk formulae (F) and 35 infants were fed partially hydrolysed whey protein formula (PHF). The results were correlated with hematological, biochemical and somatic data. Plasma zinc values decreased from birth to the age of four months in all three groups (p < 0.001). The plasma Zn level of the babies fed PHF were similar to those of breast-fed infants, whereas in F-fed children the zinc values were significantly lower (PHF, 807 +/- 106; HM, 794 +/- 112; F, 725 +/- 111 micrograms l-1; all the measurements were performed at the age of four months). In infants fed PHF formula there was a negative correlation between plasma zinc and weight or height increments. In agreement with the literature, plasma copper and ceruloplasmin increased significantly within the first four months of life. The plasma copper content was similar in either feeding group. Plasma selenium was low at birth (40 +/- 9 micrograms l-1) and remained constant in breast-fed infants. In infants on PHF there was a steeper decline of plasma Se (20 +/- 6 micrograms l-1) than in infants fed cow's milk formula (29 +/- 9 micrograms l-1). Other parameters of the Se status showed a similar pattern. Despite the different zinc, copper, and selenium supply, plus presumedly different bioavailability, all the infants thrived.(ABSTRACT TRUNCATED AT 250 WORDS)

Zinc and copper in infants fed breast-milk or different formula.

In 129 term infants at birth and at the age of 4 months, zinc and copper concentrations of plasma and urine were determined by graphite furnace atomic absorption spectrophotometry and the values correlated to other biochemical parameters and somatic data. Of the infants, 49 were exclusively breast-fed, 44 fed with various commercially available cow's milk formula, 35 fed with a hypoallergenic formula (cows's milk whey hydrolysate, commercially available, supplemented with zinc and copper). Plasma zinc values declined from birth to the age of 4 months in all three groups (P < 0.001). In formula fed children, 4 months old, the values (11.1 +/- 1.7 mumol Zn/l) were significantly lower than in breast-fed (12.2 +/- 1.7 mumol Zn/l; P = 0.004) or babies on hypo-allergenic formula (12.4 +/- 1.6 mumol Zn/l; P = 0.0015). In accordance with the literature plasma copper and caeruloplasmin values increased significantly within the first 4 months of life, the plasma levels were similar in either feeding group, only urinary copper excretion was higher in male infants on hypo-allergenic formula (P < 0.03) at the age of 4 months. There were no correlations between zinc or copper values and alkaline phosphatase. In infants on hypo-allergenic formula there was a negative correlation between plasma zinc and weight or height increments. Despite different zinc and copper supply, presumedly different bioavailability, and different plasma zinc values, all infants thrived and weight and length increments were similar in each group.

Selenium status and lipoproteins in healthy and diabetic children.

Selenium and the selenium-dependent glutathione peroxidase (GSH-Px) were measured in healthy and diabetic children from Germany and Hungary. Hyperglycemia and hyperlipidemia are present in diabetes mellitus and they are associated with increased lipid peroxidation. The selenium content of erythrocytes, whole blood and plasma, as well as of plasma glutathione peroxidase activity, were found to be low in the healthy Hungarian children compared to the healthy Germans. Both groups of diabetics had significantly higher blood selenium (1.05 +/- 0.14 versus 0.86 +/- 0.1 mumol/L in Hungarians, 1.34 +/- 0.21 versus 1.12 +/- 0.22 mumol/L in Germans) and higher plasma selenium (0.89 +/- 0.15 versus 0.68 +/- 0.01 mumol/L in Hungarians and 1.01 +/- 0.2 versus 0.88 +/- 0.19 mumol/L in Germans) than the healthy children of the same countries. In all diabetic children the plasma glutathione peroxidase activity and triglycerides were higher and the plasma HDL-cholesterols (HDLC = high density lipoprotein-cholesterol) lower than those in healthy controls. The patients showed linear correlations between blood glucose and plasma glutathione peroxidase activity, as well as in erythrocyte glutathione peroxidase activity with triglycerides (TG) and an inverse correlation with HDL-cholesterol. Plasma selenium correlated only in healthy children with triglycerides, cholesterol and HDL-cholesterol. Irrespective of the geographical region diabetics had a higher selenium status than healthy children. In addition, we found correlations between selenium and lipoproteins in the reference group. The mode of glycation, oxidative procedures and the selenium binding to lipoproteins could explain the different associations in the healthy and diabetic children.

[Nutritional iodine status of healthy infants in Germany]. / Jodversorgungszustand gesunder Säuglinge in Deutschland.

In 78 healthy term babies from Düsseldorf and surroundings spontaneous urine samples were collected on day 108 to day 144 of life and analyzed for the content of iodine and creatinine. 26 babies were breast fed. 23 babies received an iodized hypoallergenic formula and 26 babies different commercial formulas only partly iodized. From 4 parameters to estimate iodine supply of the babies (urinary iodine concentration microgram/dl, iodine/creatinine ratio microgram/g; estimated daily iodine excretion microgram/d, estimated daily iodine excretion corrected for body surface area microgram/dl 1.73 m2) estimated daily iodine excretion was the most useful parameter. Breast fed babies showed a significantly lower estimated daily iodine excretion (median 32 microgram/d) than babies fed the hypoallergenic (52 microgram/d) or a commercial formula (54 micrograms/d). In Germany with an insufficient iodine supply of pregnant and lactating mothers breast fed infants run a risk for an insufficient iodine supply. Furthermore, supplementation of infant formulas with iodine started in 1990/1991 proved to be a sufficient measure to correct iodine deficiency.

Fatty acid composition of blood lipids in Chinese children consuming high erucic acid rapeseed oil.

The fatty acid patterns of oils, blood plasma and erythrocyte lipids from 28 children in the Shaanxi province of the People's Republic of China were determined by capillary gas liquid chromatography. The main source of fat in this region is rapeseed oil. The analysis of locally available rapeseed oil shows a high erucic acid content (mean 43.83%, range 33.91-50.48%). According to protocol data, about 3% of the daily nutrient energy is provided by erucic acid. Despite a low fat intake in Chinese children, the composition of the fatty acids of the fractions analyzed showed normal patterns. However, erucic acid was found in all fractions analyzed. Data on erucic acid in human tissue are scarce. Although there are no indications of erucic acid toxicity in man, it is known to cause cardiac lipidosis and necrosis in rats. The question remains open if erucic acid aggravates selenium deficiency symptoms which are known to be associated with Keshan disease, an endemic cardiomyopathy.

Selenium status in Sudanese children with protein-calorie malnutrition.

In 68 Sudanese children with severe protein-energy malnutrition, age 1-4 years, the selenium status was investigated and the results were compared with those of healthy Sudanese and German children. The median selenium content in plasma of healthy Sudanese children (x = 59 micrograms/L) and with those of marasmus (x = 57 micrograms/L) were found to be in the same range. It was lower than in healthy German children (x = 82 micrograms/L). Patients with marasmic kwashiorkor exhibited still lower values (x = 42 micrograms/L. Within each group of malnourished children (marasmus, marasmic kwashiorkor, kwashiorkor) there were patients with low and with "normal" selenium values (taking the values of healthy German children as normal). Hair selenium values were not different between marasmic Sudanese children and healthy German children, probably due to reduced hair growth in malnourished children. Plasma glutathione peroxidase activity was reduced concomitantly with plasma selenium in the patients with protein-calorie malnutrition. There was a good correlation between plasma selenium and plasma glutathione peroxidase activity. A follow-up study showed that plasma selenium decreased during rehabilitation in those patients who had a "normal" value before treatment. This is probably due to the low selenium content of the two dietary formulae used, which contained 18 and 25 micrograms/L Se of formula,. It remains questionable whether the low selenium states and low selenium intake exhibit a healthy risk inhibiting further rehabilitation of the patients with severe protein-calorie malnutrition.

A screening method for the evaluation of selenium status.

A screening test for the estimation of the Se content in whole blood was developed. Blood was administered on to filter paper, dried at room temperature and circles of 28 mm circumference cut out. The blood volume corresponding to the stained circle amounted to 17.0 +/- 1.4 microL. The Se content was estimated by atomic absorption spectrophotometry + hydride generation technique after stepwise digestion of the blood stained filter papers. Precision (within-run 6.3%) and recovery rate (102%) were good. The screening test was used for samples from Magnesia, an area on the east coast of Greece, and Ningxia, a rural area in northeast China. The blood Se content was significantly lower in Greek mothers after birth than in Chinese mothers. Greek newborns had higher blood Se than their mothers. Greek infants showed a drastic decline in the blood Se values within the airst 4 months of life. The screening method showed good practicability in testing the blood Se content in samples from different areas of the world.

Trans fatty acid content of selected brands of West German nut-nougat cream.

The fatty acid composition including trans fatty acids of 12 brands of nut-nougat creams were analyzed by capillary gas chromatography. The creams consisted mainly of sugar and partially hydrogenated vegetable oil. The lipid content, which was quantified gravimetrically, amounted to between 30 and 38.2% in the different brands. The fatty acid composition varied considerably between the different creams. Linoleic acid, the major polyunsaturated fatty acid (PUFA), ranged from 12 to 39%. Palmitic acid (16:0), which was the main fatty acid, varied from 9 to 27%. The total trans fatty acid content of the 12 creams ranged from 0.9 to 12.3%. Only two of the creams contained less than 1% of trans fatty acids; 18:1t was the trans fatty acid found in the greatest amounts, whereas 16:1t and 14:1t were only found in trace amounts. Three samples had amounts of 18:2tt, 18:2ct, and 18:2tc between 0.7 and 1.06%; only small amounts of linoleate isomers were detected in the other creams. Our results show that trans fatty acids are present in every brand of chocolate cream tested. Since the potential risk of arteriosclerosis and cancer resulting from the consumption of trans fatty acids is not yet clear, different ways of production should be used in order to eliminate them from the creams that are a preferred bread spread of infants and children.

Acute selenium poisoning of a 2-year-old child.

After ingestion of an unknown amount of a gun blueing compound containing selenious acid (11 ml from the bottle fluid were missing, equivalent to 2.9 g Se) a 2-year-old girl suffered from continuous hyper-salivation, vomiting, diarrhoea, restlessness and muscle spasm. Blood pressure and pulse rate were increased. Symptomatic treatment was performed by parenteral fluid administration. The plasma Se concentration was increased to 20 times normal 5 h after ingestion. Erythrocyte Se exceeded plasma Se, 24 h after intoxication. Urinary Se excretion decreased parallel to the plasma Se concentration. Ten weeks later, the Se content of hair had risen to 10 times normal. The plasma glutathione peroxidase activity showed only a slight increase during the first 36 h, erythrocyte glutathione peroxidase, catalase and superoxide dismutase activities were not significantly altered. The child fully recovered.

Selenium intake of infants and young children, healthy children and dietetically treated patients with phenylketonuria.

In 20 healthy infants and children, 5-20 months old, the Se intake was estimated by analysing food samples by instrumental neutron activation analysis. The intake was calculated by weighing the portions offered and actually consumed. The median Se content of the food amounted to 27 ng/g wet weight (gww) and median daily Se intake to 33.5 micrograms. The Se intake was not equally distributed over the day. About 50% of the daily Se intake was derived from the supper. The main Se sources (41%) for young children were cereal paps. Commercially available meals (30 ng/g) contained less Se than home-made ones (50 ng/g). In nine dietetically treated patients with phenylketonuria the median Se intake amounted only to 6.9 micrograms/day corresponding to a mean Se content of the diet of 7.9 ng/g. The main Se source in the diet was vegetables (36.3%) and 20% derived from their protein supplements. The Se intake of young children, healthy or dietetically treated, cannot be calculated accurately from tables but must be estimated by measuring the Se content of the local food because cereals and vegetables--the main Se sources--exhibit great regional variations.

The selenium content of infant food.

The selenium content of food exhibits great regional differences. Food samples of infants and young children from the North Rhine-Westphalia State in the Fed. Rep. of Germany were analysed by instrumental neutron activation analysis and showed that the average selenium content of local vegetable and fruit is below 5 ng/g wet weight. Only samples of potatoes and bananas exhibit higher selenium contents. The bananas, probably imported from different areas of the world, show an extremely high variance with values between 4 and 164 ng Se/g. Commercially available ready-for-use meals for infants or young children have a low Se content (median 24 ng/g) which is comparable to cow's milk. Besides eggs, cereals enriched with milk and some other cereal products contain more than 100 ng Se/g.

Glutathione peroxidase and glutathione S-transferase activity of platelets.

A low Se intake in dietetically treated patients with phenylketonuria (PKU) or maple syrup urine disease (MSUD) leads to a marked reduction of the platelet glutathione peroxidase activity (GSHPx). The mean value amounted to 2.0 U/10(11) platelets with t-butyl hydroperoxidase (t-BOOH) (2.2 U/10(11) with H2O2) in patients and 5.8 U/10(11) with t-BOOH (5.4 U/10(11) with H2O2) in the control children. After Se supplementation with yeast rich in Se (dose: 135 micrograms Se/m2) the GSHPx activities rapidly increased. They reached a plateau after 2-3 weeks and remained there during the following 15-20 weeks of supplementation. After the cessation of supplementation there was a slow decrease, the values reached a low plateau after 24 weeks. In addition platelet glutathione S-transferase (GSHTf) was estimated with 1-chloro-2,4-dinitrobenzene. No significant difference between the values in healthy and dietetically treated patients in a low or normal Se state was observed. GSHTf did not exhibit peroxidase activity and did not show a compensatory increase when Se dependent GSHPx activity was low. The patients do not reveal clinical signs of disturbed platelet function. GSHPx may act in platelets via lipoxygenase on the prostaglandin pathway. The physiologic consequence of altered arachidonate metabolism, when GSHPx is deficient in platelets, remains to be elucidated.

Zinc status of Libyan children -- a pilot study.

Hair zinc has been investigated in children of North and South Libya. The hair zinc content amounts to 213 +/- 36 micrograms/g in newborns. There is no difference between the values of newborns from North Libya and newborns from South Libya. The hair zinc values decrease during infancy. In toddlers and school-children the hair zinc content is 88 +/- 35 micrograms/g, 89 +/- 25 micrograms/g resp. These values are as low as those reported in American children with low height percentiles or nearly as low as those found in dwarfs with poor zinc status from Egypt and Iran.