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.

[Duplicate study on the dietary intake of some metals/metalloids by children in Germany. I. Arsenic and mercury]. / Duplikatstudie zur Aufnahme von einigen Metallen/Metalloiden bei Kindern in Deutschland. Teil I: Arsen und Quecksilber.

The dietary intake of arsenic and mercury by 47 children (aged 5-8 years) living in West-Germany (Duisburg) is reported. Duplicate portions of all food and beverages were obtained on 2 days. Arsenic and mercury were measured by atomic absorption spectrometry under careful quality control. Results of are shown in the following table. [table: see text] Fish was consumed at 3 of 94 sampling days only. The arsenic and mercury intake on days with fish consumption was much higher compared with the other days (median, range): arsenic 8821; 4431-11954; mercury 123.7; 80, 0-167.5 ng/kg b.w. and day. The dietary arsenic and mercury intake was much lower than the FAO/WHO PTWI. For mercury the median intake amounted to 1.7% on days without and to 16.6% on days with fish consumption, for arsenic on days without fish consumption to 5.2% PTWI (only for inorganic arsenic compounds established) and on days with fish consumption (in fish mainly organic arsenic occur) 411% of PTWI. Based on the PTWI our data indicate no health risks for German 5-8-year-old children due to arsenic and mercury dietary intake.

[Duplicate study on the dietary intake of some metals/metalloids by children in Germany. part II. Aluminum, cadmium and lead]. / Duplikatstudie zur alimentären Aufnahme von einigen Metallen/Metalloiden bei Kindern in Deutschland. Teil II: Aluminium, Cadmium und Blei.

The dietary intake of aluminium, cadmium and lead by 47 children (aged 5-8 years) living in West-Germany (Duisburg) is reported. Duplicate portions of all food and beverages were obtained on 2 days. Aluminium, cadmium and lead were measured by atomic absorption spectrometry under careful quality control. Results are shown in the following table. [table: see text] The dietary intake of aluminium was low. The median amounted to 2.9% and the maximum value to 11.2% of the FAO/WHO PTWI. The correspondent data for cadmium were 30.2 and 98.7% and for lead 22.2% and 72.1% respectively.

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)

Macronutrient, copper, and zinc intakes of young German children as determined by duplicate food samples and diet records.

Daily energy, protein, fat, carbohydrate, zinc, and copper intakes of 47 healthy 5- to 9-year-old children living in Duisburg, an industrial area of North Rhine-Westphalia, and consuming self-selected diets were calculated using a 4-day weighed dietary records and food composition values. In addition, the parents of the subjects also collected a 24-hour food composite on 2 of the recording days for analysis of the nutrients. This allowed us to compare the calculated value of the nutrients on days when only dietary records were made with those on which also duplicate samples were collected. Daily analyzed intakes were also compared with those calculated from the recording days. Zinc and copper were estimated by atomic absorption spectrometry. The results show that there were reductions in the intake of all nutrients on days when duplicate samples were also collected as compared with the days when only dietary records were made. Median daily calculated intakes for all children on the 4 record days were: energy 1,578 kcal, protein 46.5 g, fat 67.3, carbohydrates 174.7 g, zinc 5.3 mg, and copper 1.0 mg. The median analyzed intakes were: energy 1,367.7 kcal, protein 37.1 g, fat 49.1, carbohydrates 178.7 g, zinc 5.3 mg, and copper 0.7 mg. The use of the duplicate diet method has shown that a 4-day recording period gives an overestimation of the nutrient intake. The calculated and the analyzed zinc intakes did not meet the recommended levels of the Deutsche Gesellschaft für Ernährung. The median copper intakes were in the lower range of the levels recommended by the Deutsche Gesellschaft für Ernährung.

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.

Cadmium, copper, lead and zinc concentrations in hair and toenails of young children and family members: a follow-up study.

In a follow-up study concentrations of cadmium, copper, lead and zinc (measured by atomic absorption spectrometry) in scalp hair and toenail clippings of 47 children (5-9 years) were compared with previous values (2 years earlier). Family members were also monitored. Twenty-five of the children selected have had either high hair values of Cd, Cu, Pb or low hair Zn concentrations or combinations of these (group A) in the first study. Control group comprised 22 children (B). At the follow-up study, there were no more differences between group A and B. Between the first and follow-up study Cd and Pb levels in hair and toenails of group A children declined (geometric means; hair Cd: 265 vs. 111 ng/g; hair Pb: 10.1 vs. 3.8 micrograms/g; toenail Cd: 720 vs. 335 ng/g; toenail Pb 18.5 vs. 5.8 micrograms/g) and hair Zn values increased (54 vs. 103 micrograms/g). Fathers of exposed children had more Cd and Pb in hair and toenails than fathers of control children (hair Cd: 88 vs. 48 ng/g; hair Pb: 4.4 vs. 1.3 micrograms/g; toenail Cd: 46 vs. 23 ng/g; toenail Pb: 1.3 vs. 0.7 microgram/g). No conclusive findings were obtained for Cu. With respect to heavy metal levels of mothers and brothers and sisters there was no uniform pattern. Children < 5 years of age are especially prone to higher Cd, Pb exposure and to lower Zn status compare with older children.

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.

Zinc in lymphocytes--the assessment of zinc status in patients with Crohn's disease.

A group of 26 Crohn's disease patients was compared to a healthy control group with regard to their zinc status in plasma, urine, hair, and lymphocytes. A method for lymphocyte preparation, which was in part newly designed, was used; it proved to be very effective as to recovery and purity of the harvested cell fraction. Results of the study suggest that an accurate estimation of zinc status can be more reliably obtained by determination of lymphocyte zinc--provided the cell preparation described is used--than by using any other of the examined body compartments.

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.

Monitoring of cadmium, copper, lead and zinc status in young children using toenails: comparison with scalp hair.

Cadmium, copper, lead and zinc concentrations were determined (atomic absorption spectrometry) in the proximal end of scalp hair (n = 474) and in toenail clippings (n = 461) of children, aged 3-7 years, living in an industrialized and in a rural area of the Federal Republic of Germany. With the exception of Zn in hair, levels of the elements were log-normally distributed. Data are presented as geometric means. Toenail Cd and Pb levels were much higher than those in hair (Cd, 457 vs 90 ng g-1; Pb, 8.5 vs 2.7 micrograms g-1), while Cu and Zn values were similar in both biological media (toenail vs hair: Cu, 7.5 vs 10.6 micrograms g-1; Zn, 129 vs 108 micrograms g-1). In toenails, all elements were positively correlated with each other. In hair, there was a close relationship only between Cd and Pb; Cd and Pb were inversely related to Zn. With the exception of Zn (no correlation), there was a minor relationship between metal levels in hair and those in toenails. Using stepwise regression analysis, seasonal variation was found to be the main factor influencing hair metal levels, while nail metal levels were mainly influenced by place of residence (with the exception of Cu concentrations, for which there were no significant predictors). Multiple correlation coefficient was higher for hair than for nails. It is concluded that, for biological monitoring, toenail clippings are less suitable than hair samples.

[Skin changes in alimentary zinc deficiency caused by artificial infant food]. / Hautveränderungen bei alimentärem Zinkmangel durch künstliche Säuglingsernährung.

We report on 2 non-related newborn children who developed erythematosquamous skin eruptions on both their faces and the extensor sides of their fingers at the 4th and 10th week after birth, resp. Both children had been fed upon hypoallergenic formulas since birth. Serum investigations revealed decreased zinc levels: 0.4 and 0.17 mg/l, resp. (normal values: 0.59-0.96 mg/l). Following zinc substitution with zinc sulphate 10 mg daily for 3 days, the serum zinc levels of both children had increased to normal values and remained stationary during continued treatment with 3 mg zinc daily. The skin eruptions disappeared a few days after the start of treatment.

Hair lead levels in young children from the F.R.G.

Hair lead (PbH) levels were measured in 474 children, aged 3-7 years, living in an industrialized (Duisburg) and in a rural area (Westphalia) of the F.R.G. by atomic absorption spectrometry. PbH values were log-normally distributed. All mean concentrations are therefore given as geometric means. The overall mean PbH content was 2.7 mg/kg. In the summer PbH levels were higher than in the winter (3.8 vs. 1.4 mg/kg) and the values from the urban children were higher compared with those from rural children (3.7 vs. 1.9 mg/kg). Boys had more Pb in their hair than girls (3.9 vs. 2.0 mg/kg) and PbH levels decreased between the 4th and 7th year. In the industrialized area the PbH content of children whose fathers were factory workers, was higher than that of children whose fathers had other occupations (4.2 vs. 3.0 mg/kg). Non-German children had more Pb in their hair than German children (5.2 vs. 3.6 mg/kg). Pb content in the soil from the Duisburg area was related to PbH concentrations (R = 0.34). Since our observations are in line with the results of similar studies which used blood samples to monitor Pb exposure in children, we conclude that by using standardized conditions hair analysis is a valuable screening method.

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.