Respiratory capacity differed between categories of patients at least for the first three months of observation, probably due to the inflammatory factors that are released with the influenza A (H1N1) infection and underlying disease. Importantly, the respiratory inflammation lasted almost two months, as evidenced by the fact that respiratory capacity remained stable between the second and third measurement. Several treatment modalities can be administered to confer protection and suppress the inflammation. Vaccination and early treatment with antiviral agents represent the mainstay of management. Milk Lacking α-Casein Leads to Permanent Reduction in Body Size in Mice The major physiological function of milk is the transport of amino acids, carbohydrates, lipids and minerals to mammalian offspring. Caseins, the major milk proteins, are secreted in the form of a micelle consisting of protein and calcium-phosphate. We have analysed the role of the milk protein α-casein by inactivating the corresponding gene in mice. Absence of α-casein protein significantly curtails secretion of other milk proteins and calcium-phosphate, suggesting a role for α-casein in the establishment of casein micelles. In contrast, secretion of albumin, which is not synthesized in the mammary epithelium, into milk is not reduced. The absence of α-casein also significantly inhibits transcription of the other casein genes. α-Casein deficiency severely delays pup growth during lactation and results in a life-long body size reduction compared to control animals, but has only transient effects on physical and behavioural development of the pups. The data support a critical role for α-casein in casein micelle assembly. The results also confirm lactation as a critical window of metabolic programming and suggest milk protein concentration as a decisive factor in determining adult body weight. Milk is a hallmark of mammals, providing the primary source of nutrition for their young until weaning. It is an emulsion of fat globules in a water-based fluid. The major proteins of this fluid are the caseins. The caseins are serine rich phosphoproteins which are almost exclusively expressed in the lactating mammary gland [1, 2] . In cows the casein proteins together constitute up to 80% of total milk protein and also 80% of total mRNA in the lactating mammary gland [3] . The caseins are members of a large family of serine rich phospho-proteins, which are clustered on chromosome 5 in the mouse (chromosome 6 in cattle, chromosome 4 in humans). There are 5 functional casein genes in the mouse whereas most other species (including ruminants) only express 3 or 4 functional genes [1] . The casein proteins show little homology with each other outside their signal peptide domain [2, 4] .