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Biomedical subjects

H Deelstra

Publications and source records attributed to H Deelstra.

13 recordsLinked to original sources
PubMed1992

Selenium content of goat milk and its distribution in protein fractions.

This study reports on selenium distribution in goat milk. Skim milk was found to contain the major part (94%) of total milk selenium. The selenium distribution over casein and whey protein fractions depends on the separation method used, but irrespective of these methods, skim milk selenium is mainly associated with the casein fraction (greater than 69%). Approximately 9%, 7% and 24% of selenium is removed by dialysis (molecular cutoff 10-12 kDa) from skim milk, casein and whey respectively, indicating a major association of selenium with milk proteins. This observation is confirmed by selenium analysis of individual caseins and whey proteins isolated through ion-exchange chromatography and gel filtration. Selenium concentrations of the different isolated milk proteins show considerable variation (caseins: 294-550 ng Se/g; whey proteins: 217-457 ng Se/g).

Animals↗
PubMed1992

Mn-content of total parenteral and enteral nutrition.

Manganese has been proven to be an essential trace element in animals since 1931. Today, it is known that manganese deficiency results in a wide variety of structural and physiological defects in animals. For humans, the safe and adequate range of intakes for manganese by enteral nutrition is 2.0 to 5 mg per day; for parenteral nutrition a range of 0.15 to 0.8 mg per day is proposed. The manganese content of components of enteral nutrition (EN) and total parenteral nutrition (TPN) solutions is determined using electrothermal atomic absorption spectrometry. Comparison is made between calculated and measured values. The manganese present in supplementary nutrition and flavor stuffs is also measured. The intake of manganese by EN is calculated based on the daily administration, and is found to vary from 192 to 7373 micrograms per day. In prepared TPN-solutions, the manganese contribution of all components before adding the Oligo Complex is found to be less than 0.2% of the total manganese content. After addition of the Oligo Complex mixture, a mean daily intake of 5.02 +/- 0.16 mg per day is found.

Enteral Nutrition↗
PubMed1991

Atomic absorption spectrometric determination of zinc, copper, and selenium in fish from Lake Tanganyika, Burundi, Africa.

Atomic absorption spectrometric determination of zinc, copper and selenium in fish from Lake Tanganyika (Burundi) shows that, although this lake is not polluted, trace element intake by fish contributes an important part of the elemental intake by man. No correlations were found between trace element levels in the fish and fish lipid and protein content. Copper and zinc were positively and highly correlated (P less than 0.005). Interspecies comparison for trace element content of fish samples is discussed. Unless the level of water pollution is taken into account, intraspecies variation cannot be evaluated.

Animals↗
PubMed1990

Determination of selenium in blood components by X-ray emission spectrometry. Procedures, concentration levels, and health implications.

Sampling, storing, sample pretreatment, and experimental conditions for selenium (Se) determination in human serum, plasma, and whole blood by X-ray emission spectrometric (XRS) methods are described. Concentration levels in these biological fluids, found by this technique, are discussed and compared to values found by other techniques for the same healthy population group in the same area. XRS analysis of blood from patients with various pathological conditions is reviewed, with special attention to the relation of Se with the concentration level of other essential or nonessential trace elements.

Adult↗
PubMed1990

Direct selenium determination in human whole blood by graphite furnace atomic absorption spectrometry with deuterium correction using a L'vov-platform, a Pd/Mg matrix modification and appropriate dilution.

A mixture of palladium/magnesium nitrate was used as matrix modifier in graphite furnace atomic absorption spectrometry for the direct determination of selenium in human whole blood Addition of HCl up to 0.2 M, a twenty-five fold diluted sample and an appropriate furnace program are necessary to eliminate the interference of iron. Reproducibility of less than 3% at the 95 micrograms/L level, a detection limit of 10 micrograms/L and good accuracy, as determined by intercomparison runs and recovery of spiked samples, are obtained. The proposed method can be used for analysing 4 blood samples per hour.

Deuterium↗
PubMed1990

Selenium concentration levels in whole blood of Belgian blood bank donors, as determined by direct graphite furnace atomic absorption spectrometry.

Direct graphite furnace atomic absorption spectrometry after appropriate sample dilution is applied to whole blood of Belgian blood bank donors from different geographical areas. Highest values were obtained for the northern part of the country (Flanders). Different consumption habits may explain the significant difference in selenium level found for the two cultural communities (Flemish and Walloon). No sex difference was obtained in both parts of the country and no influence of age was observed for the two communities. Values obtained are compared with literature data on whole blood selenium content for other European countries.

Adult↗
PubMed1988

Daily chromium intake by infants in Belgium.

The chromium content of human breast milk, infant formulae, cow's milk and beikost was measured by graphite furnace atomic absorption spectrometry following different digestion steps. No significant variation in chromium concentration during lactation was found. The mean concentration was 0.18 ng/ml. The daily chromium intake for Belgian infants of 3 months of age using different types of food was estimated. Exclusively breast fed infants consumed 0.1 microgram/day, while for infants fed cow's milk the intake was five times higher. The exclusive use of commercial infant formulas resulted in an intake of 2 up to 10 micrograms chromium a day.

Adult↗
PubMed1987

Vitamin E and selenium concentrations in milk and milkfractions.

Cow's milk of different lactation stages and of different seasons was analysed for its vitamin E and selenium contents. The concentrations of these nutrients vary with the lactation stage as well as with the sampling period. The results are compared with corresponding values for human milk. Cow's milk has appreciatly lower concentrations of vitamin E; the selenium content of cow's and human milk are the same. The lack of vitamin E when cow's milk is used for infant formulae is compensated for the addition of alpha-tocopheryl acetate. The selenium concentration of different protein fractions of cow's milk was determined. It was found that the whey proteins contain more selenium than the caseins.

Animals↗
PubMed1985

Trace elements in human milk, selenium a case study.

Longitudinal changes of the trace element (Fe, Cu, Zn, Mn, Mo, Cr, Co, As, Se) composition of human milk are discussed. The mean daily intake of breast fed infants is compared with the intake of infants fed cow's milk and with recommended dietary allowances. Parameters which can be used to check the selenium status are discussed. Clinical consequences of selenium deficiency are discussed.

Arsenic↗
PubMed1985

Daily intake of selenium by bottle-fed infants in Belgium.

The selenium content of commercial infant formulae, processed milk and beikost was measured by hydride generation atomic absorption spectrometry after previous wet acid digestion. The median daily intake by infants (1-6 months) fed milk, soya or cereal-based infant formulae was 3.0-7.8 micrograms/day; lower than the mean daily intake by Belgian breast-fed infants (6.1-8.6 micrograms/day) and cow's milk bottle-fed infants (7.6-10.8 micrograms/day).

Animals↗
PubMed1985

Longitudinal study of the selenium content in human breast milk in Belgium.

The selenium content of expressed human milk obtained at different stages of lactation from 32 lactating mothers was measured by hydride generation atomic absorption spectrometry after previous wet acid digestion. The highest selenium level was found in colostrum (14.8 ng/g; wet weight), subsequently the content declined and plateaued off after one month (9.4 ng/g; wet weight). The daily selenium intake for Belgian infants of 3 months of age was found to be 7.1 micrograms (girls) and 8.1 micrograms (boys), which is lower than the values obtained in most other countries and lower than the recommended safe and adequate daily intake of 10 to 40 micrograms/day for the same age group.

Adolescent↗
PubMedDate not supplied

Selenium content of livers from sex-linked dwarf and normal broiler breeders. Influence of a thyrotropin-releasing hormone-induced growth hormone release.

Plasma concentrations of cGH, T3, and T4 were not different between dwarf and normal broiler breeders. Normal hens had a liver selenium content of 710 +/- 35 ng/g, and dwarf hens 656 +/- nine ng/g (n = 8). Following injections into a wing vein of different doses (1.5, 3, 6, 12, and 24 micrograms/kg) of the hypothalamic hormone TRH, GH was increased after 15 min. This effect seemed to last longer in dwarf chickens. Plasma concentrations of T3 increased significantly 1 h after TRH in normal hens, but TRH was ineffective in raising T3 levels in dwarf animals. The selenium content of livers obtained following decapitation after 2 h was also increased in normal hens up to 902 +/- 42 ng/g using the highest dose of TRH (24 micrograms/kg). This seemed not to be the case for dwarf animals. A much smaller number of hepatic cGH receptors was also found in dwarf hens, whereas the affinity of the hepatic GH receptor was not influenced by the genotype. It is concluded that the sex-linked dwarf hens are unable to increase their hepatic T4 into T3 conversion following a TRH challenge probably because of a deficiency in hepatic GH receptors. The lower content of selenium in dwarfs and their inability to increase its uptake after TRH seem therefore to support the hypothesis that selenium has a direct role in the activity of the 5'-deiodinase complex.

Animals↗