Longitudinal analysis of protein glycosylation and β-casein phosphorylation in term and preterm human milk during the first 2 months of lactation.

Human milk proteins provide term and preterm infants with both nutrition and protection. The objective of the present study was to examine longitudinal changes in the protein composition of term and preterm milk during the first 2 months of lactation, focusing on protein phosphorylation and glycosylation. Using gel electrophoresis, the relative concentration and glycosylation status of lactoferrin, secretory Ig A, β-casein, α-lactalbumin, serum albumin, bile salt-stimulated lipase, xanthine oxidoreductase, tenascin and macrophage mannose receptor 1 were measured in milk collected on days 7, 10, 14, 18, 21, 28 and 60 postpartum from preterm mothers (28-32 weeks gestation, n 17).

Investigation of short-term variations in casein and whey proteins in breast milk of term mothers.

Objectives: We investigated changes in breast milk whey and casein proteins, between fore and hind milk during breast expression, between breasts and within 24-hour period during breast-feeding. This has implications for developing an appropriate sampling protocol for investigating the influence of milk composition on gastric emptying and infants' feeding behaviour.

Methods: Breast milk samples were collected from mothers (n = 25) of healthy term infants ages 1 to 8 months.

Proteome mapping of human skim milk proteins in term and preterm milk.

The abundant proteins in human milk have been well characterized and are known to provide nutritional, protective, and developmental advantages to both term and preterm infants. However, relatively little is known about the expression of the low abundance proteins that are present in human milk because of the technical difficulties associated with their detection. We used a combination of electrophoretic techniques, ProteoMiner treatment, and two-dimensional liquid chromatography to examine the proteome of human skim milk expressed between 7 and 28 days postpartum by healthy term mothers and identified 415 in a pooled milk sample.

Biodegradation of poly(2-hydroxyethyl methacrylate) (PHEMA) and poly{(2-hydroxyethyl methacrylate)-co-[poly(ethylene glycol) methyl ether methacrylate]} hydrogels containing peptide-based cross-linking agents.

PHEMA-peptide and P[HEMA-co-(MeO-PEGMA)]-peptide conjugate hydrogels [where PHEMA = poly(2-hydroxyethyl methacrylate; PEGMA = poly(ethylene glycol) methacrylate] were readily prepared via photoinitiated free-radical polymerization in water. The PHEMA-peptide hydrogels were opaque and had a heterogeneous morphology of interconnected polymer droplets, characteristic of polymers that separate from the aqueous phase during the polymerization experiment. The P[HEMA-co-(MeO-PEGMA)]-peptide conjugates were transparent gels with a homogeneous morphology when formed in water, but when formed in aqueous NaCl solutions the P[HEMA-co-(MeO-PEGMA)]-peptide conjugates were also opaque and exhibited the heterogeneous morphology of interconnected polymer droplets.

Evaluation of a mid-infrared analyzer for the determination of the macronutrient composition of human milk.

A mid-infrared human milk analyzer (HMA) is designed to measure the macronutrients in human milk over a wide range of concentrations. Human milk samples (N = 30, 4 different dilutions each) were used to compare the macronutrient levels determined by the HMA to those derived from traditional laboratory methods. There was a small but statistically significant difference in the levels of fat, protein, lactose, total solids, and energy for all samples.