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Biomedical subjects

L Hambraeus

Publications and source records attributed to L Hambraeus.

At least 19 recordsLinked to original sources
PubMed1992

Iron absorption differs in piglets fed extrinsically and intrinsically 59Fe-labeled sow's milk.

Iron bioavailability from species-specific milk is assumed to be high for the offspring, possibly due to species-specific iron-binding proteins in the milk. To assess this bioavailability using radioisotopes, the validity of extrinsic labeling technique needs to be proven. Using the suckling piglet as an animal model, we have compared iron bioavailability from sow's milk labeled extrinsically and intrinsically. During intrinsic labeling transfer into milk of 59Fe given intramuscularly was slow and was found to be at maximum 14 h post-injection. Recovery of isotope in the milk was only 0.00014%. Extrinsic and intrinsic labels were distributed differently among milk fractions; intrinsic iron bound primarily to the fat fraction but the extrinsic iron bound primarily to the casein fraction. Iron retention from intrinsically labeled milk was considerably higher than from extrinsically labeled milk. These results show that the extrinsic tag method is not valid for studies on iron absorption from sow's milk and suggest that the situation may be the same for human milk.

Absorption↗
PubMed1991

[Influenza and death. High mortality not only due to the great epidemics].

Excess mortality in a population is one of the hallmarks of an influenza epidemic. Apart from the pandemic years, 1918-1919, 1957 and 1968-1969, annual excess mortality has occurred 16 times in Sweden during the period 1911-1988. An unusually high mortality was caused by Influenza A Sichuan 2/87 (H3N2), the unexpected appearance of which at the beginning of November 1988 started an intensive epidemic in Sweden, while other European countries had a relatively mild influenza season. Swedish deaths in December totalled 10,500-2,200 more than expected; age groups over 65 years accounted for 95 per cent of the mortality, and those over 80 (N = 350,000 in Sweden) for 1,400 deaths. 0.4 percent of those over 80 died. The excess mortality is to be explained by the high proportion of the elderly in the Swedish population and the very low rate of influenza vaccination before the outbreak. As the increase in the proportion of the very elderly can be expected to continue, future influenza epidemics will result in even higher mortality unless adequate prophylactic measures are taken.

Adult↗
PubMed1978

Effects of proteins and their corresponding amino acid mixtures on nitrogen balance and body composition in the growing rat.

The efficiencies of nitrogen utilization from intact proteins (casein, gluten, soybean, egg albumin) were compared to that of the respective synthetic amino acid mixtures. Food intake, growth, NER (nitrogen efficiency ratio), (Nitrogen retained/Nitrogen intake) X 100, BV (biological value), TD (true digestibility), liver weight and body composition were estimated on growing rats. Rats fed amino acid mixtures simulating casein, egg albumin and soybean consumed more food and showed more rapid growth than rats fed the intact proteins. Differences in nitrogen utilization and body composition were occasionally observed between the respective intact protein and amino acid mixtures but were in most cases not significant. It is concluded that nutrition with intact proteins cannot be assumed to be equivalent to nutrition with the corresponding amino acid mixture. However, general differences between the two types of feeding regimens were not obvious since the results were influenced by factors such as the amino acid composition of the protein and the amino acid mixture as well as the methodology used for nutritional evaluation. (Nitrogen retained/Nitrogen intake) X 100 and BV but not NER of an amino acid mixture formulated according to a commercial elementary diet was found to be low compared to casein.

Amino Acids↗
PubMed1978

Nitrogen and protein components of human milk.

The true protein content of human milk is 0.9%, in well-nourished as well as malnourished mothers. Casein constitutes only about 20% of the protein nitrogen in human milk. The remaining 80% is derived from the whey proteins, the three dominant components being alpha-lactalbumin, lactoferrin and secretory IgA. alpha-lactalbumin is a subunit of lactose synthetase. Lactoferrin is an iron-binding glycoprotein which plays a role in the defence against gastro-intestinal infections and is probably also involved in iron transport in the gut. Secretory IgA is comparatively stable at low pH; it is resistant to proteolytic enzymes and plays an essential role in the immunological defence against gastro-intestinal infections. Lysozyme is a minor component of the whey proteins and represents an active enzyme with a bactericidal effect. The nutritional and immunological significance of the marked differences with respect to the nitrogen and protein compositions of human milk and cow's milk should not be underestimated, but need further elucidation.

Animals↗
PubMed1977

The protein quality of instant blends for infants and children based on milk or cereals and milk.

The protein quality of industrially produced and home prepared milk or cereal-milk based foods for infants and children were evaluated by means of biological assays. The net protein utilization (NPU) values of human milk substitutes based on cow's milk varied between 75 and 78 and the NPU of a soy-based product was found to be 70. Cereal-milk based precooked gruel powders had NPU values of 69 to 77. Furthermore, a comparison between industrially processed products and their corresponding home prepared alternatives was made. Although the protein nutritional products, i.e., including the vitamine and mineral content, is more standardized due to supplementation. The NPU assays of some cereal-milk based porridge powders revealed a wide variations (28 to 69); the lowest NPU values reflect the influence of the processing technique. This illustrates the necessity of performing biological evaluations of processed foods.

Animals↗
PubMed1976

A longitudinal study of the protein, nitrogen, and lactose contents of human milk from Swedish well-nourished mothers.

The contents of total nitrogen, nonprotein nitrogen, lactose, and individual milk proteins have been determined in human milk from well-nourished Swedish mothers. Breast milk samples from 50 mothers at different stages of lactation (up to 170 days) were collected. Furthermore, three mothers gave samples repeatedly throughout the whole lactation period. The protein content in mature milk was found to be 0.8 to 0.9% by amino acid analysis. The nitrogen content and the contents of the major human milk whey proteins, alpha-lactalbumin and lactoferrin, are very high for the first few days, then decrease rapidly and reach, thereafter, the more slowly declining level of mature milk. Nonprotein nitrogen and the nonspecific milk protein serum albumin are present in constant concentrations throughout lactation. The daily milk volumes were determined and found to be 500 to 600 ml in the very early part and 700 to 800 ml in the later part of the lactation period.

Female↗
PubMed1976

Breast milk composition in Ethiopian and Swedish mothers. II. Lactose, nitrogen, and protein contents.

Breast milk from underprivileged and privileged Ethiopian mothers was collected at different stages of lactation and analyzed for total nitrogen, nonprotein nitrogen, lactose, and individual milk proteins (lactoferrin, alpha-lactalbumin, serum albumin, IgG and IgM). These values and the milk volume of one meal were compared to corresponding results from well-nourished Swedish mothers. No significant differences between the levels of these constituents or the milk volumes were found between the two groups of Ethiopian mothers. When comparison was made between breast milk from these two Ethiopian groups and the Swedish group, the former two showed significantly higher values for the iron-binding protein lactoferrin.

Ethiopia↗