Search

The immunochemically pure preparation of lactoferrin was isolated from human colostrum and used for the immunization of animals with a view of obtaining antiserum, and also as a reference preparation for the determination of the content of lactoferrin in the standard. The monospecific antiserum to lactoferrin, obtained as the result of this procedure, was used for the determination of the content of lactoferrin in samples of human milk by the method of radial immunodiffusion. Through the content of lactoferrin in human milk showed considerable fluctuations, its level essentially decreased on the second week of lactation. In cases of the microbial contamination of milk the tendency towards an increase in the content of lactoferrin was observed irrespective of the time of lactation.

Radioimmunoassay was conducted to study the content of triiodothyronine and thyroxine in the human milk and in the blood serum of mature and premature newborns. It was established that with the growth of the lactation period the content of triiodothyronine and thyroxine rose; it was, respectively, 0.5 +/- 0.12 and 100.3 +/- 8.4 nmol/l in colostrum, 9.2 +/- 0.7 and 271.3 +/- 14.1 nmol/l in transient milk, 11.1 +/- 1.07 and 405.0 +/- 21.4 nmol/l in fully formed milk. Fully formed milk contains three times more triiodothyronine and thyroxine than the blood serum of newborns. The mature newborns have a sufficiently formed thyroid function. The level of thyroid hormones in the blood serum of premature newborns is decreased in proportion to the stage of their prematurity. They receive the deficient hormones through the human milk. The authors recommend that the nutrition of premature newborns receiving mixed and artificial feeding should be supplemented with thyroid hormones.

The studies on lactating black-and-white cows have shown that the content of albumins as well as of lactate, ammonia and glutamate in colostrum and milk of cows is higher in winter and spring but the level of beta- and gamma-globulins, citrate and urea is lower than the analogous indices in cows in summer. The concentration of alpha-globulins, oxaloacetate, malate and pyruvate in colostrum and milk did not change with the season.

The role of breast milk in the provision of the newborn with the sex hormone progesterone was studied. The radioimmunoassay was used to estimate the hormone content in the breast milk during lactation (87 samples) and in the blood plasma of 59 newborns. It was found that during the early postnatal period the progesterone level in the newborn's blood was gradually lowered. The newborn are deprived of placental progesterone as a result of the break of the chain "mother-placenta-fetus" after delivery, that leads to the reduction of the blood progesterone level. At the same time, the high level of progesterone with the necessary amount of the hormone in the period of the postnatal adaptation. The progesterone level in the mature breast milk decreases, however, with the growth of the milk amount received by the newborn the daily progesterone level significantly rises.