de Gamarra E, Bahy C
Arch Fr Pediatr. 1985 Aug-Sep;42 Suppl 1:601-4.
Nitrogen fractions in human milk (total nitrogen, non protein nitrogen, casein nitrogen and soluble protein nitrogen) were determined by direct dosage or by calculation during the first 7 days of lactation in 61 mothers feeding artificially. Twenty-five delivered at term and 36 prematurely. In all cases a decrease in all nitrogen fractions was observed. The amounts of total nitrogen and soluble proteins were similar in both groups. A difference in the distribution of the nitrogen fractions occurs only on the 8th day following delivery. Milk from mothers who deliver prematurely contains more casein and less non protein nitrogen amounts.
对61名人工喂养的母亲在哺乳期的前7天，通过直接测定或计算的方式，测定了母乳中的氮组分（总氮、非蛋白氮、酪蛋白氮和可溶性蛋白氮）。其中25名足月分娩，36名早产。在所有情况下，均观察到所有氮组分减少。两组的总氮和可溶性蛋白含量相似。氮组分的分布差异仅出现在分娩后的第8天。早产母亲的乳汁中酪蛋白含量更高，非蛋白氮含量更低。
