Mitogenic Activity and Epidermal Growth Factor Content in Human Milk

ABSTRACT. The concentration of epidermal growth factor (EGF) was determined by radioimmunoassay in colostral and mature human milk. The content of EGF in colostral milk was 25-38 ng/ml compared to 5.2-11.5 ng/ml in samples of mature milk. The radioimmunoassayable EGF content in mature milk was not influenced by pasteurization and EGF was detected in a preparation of human milk protein at a concentration similar to that found in mature milk. The growth promoting activity in human milk measured by ³H-thymidin incorporation in human fibroblasts was higher in colostral milk (stimulated incorporation 8.7.fold) than in mature milk (stimulated incorporation about 7-fold).     

五种重组人生长激素促生长作用比较

目的比较5种重组人生长激素(rhGH)促进去脑垂体大鼠生长发育的作用。方法选用清洁级Wistar大鼠,采用手术去除脑垂体的实验方法,去脑垂体手术后2周,按体质量随机分为:假手术组、去脑垂体模型组、rhGH-1组、rhGH-2组、rhGH-3组、rh-GH-4组和rhGH-5组,每组20只。各给药组大鼠每天每只皮下注射给药1次,给药剂量均为50μg/只,给药周期为14 d。假手术组与模型组动物通过相同途径给予相同体积的注射用溶媒。以体质量增加及胫骨骨骺板宽度为检测指标,观察5种rhGH对去脑垂体大鼠生长发育的影响。结果皮下注射给药14 d后,5种rhGH给药组动物体质量增加及胫骨骨骺板宽度均明显高于模型组(Pa<0.01);rhGH-1组大鼠体质量增加值明显大于rhGH-2、rhGH-3、rhGH-4和rhGH-5组(Pa<0.05,0.01),rhGH-1组大鼠胫骨骨骺板宽度也明显大于rhGH-3和rhGH-4组(Pa<0.05,0.01)。结论本实验所用5种rhGH对去脑垂体模型大鼠均具有明显的促进生长发育作用,且赛增rhGH注射液促进生长作用明显优于其他4种。     

Longitudinal Study in Biochemical Composition of Human Milk During First Year of Lactation

The composition (total solids, total protein, casein, coagulable proteins, lactose, fat, and ash) and mineral content (calcium, phosphorus, sodium, potassium, magnesium, zinc, and copper) of human milk was estimated longitudinally for the first year of lactation. Concentration of various nutrients, except zinc and copper, remained nearly constant throughout the first year of lactation and did not show any specific trend of variation. Zinc and copper decreased linearly in the first 6 months. Milk composition was found identical to the data reported from developed countries.     

Cellular Composition Including Lymphocyte Subsets in Preterm and Full Term Human Colostrum and Milk

ABSTRACT. The cellular composition of colostrum (within 72 hours post partum) and mature milk samples (5th–7th day post partum) from 20 mothers delivering preterm babies and 20 mothers delivering full term babies was examined. Lymphocyte subsets including T cells, B cells, T⁴ and T⁸ cells were quantitated by indirect immunoperoxidase staining using specific monoclonal antibodies. The mean total cell count in preterm colostrum (9 338/mm³) was significantly higher than in full term colostrum (5 594/mm³). Similarly, counts for macrophages, neutrophils and lymphocytes were significantly higher in preterm colostrum and milk as compared to full term colostrum and milk. B and T lymphocytes including T⁴ and T⁸ cells were identified in both preterm and full term breast milk. The absolute count of T, B, T⁴ and T⁸ cells was significantly higher in preterm colostrum compared to term colostrum, though the relative percentage distribution of lymphocyte subsets showed no significant difference between the two groups. T and B cells constituted about 74% and 26% of total lymphocytes, respectively in preterm as well as full term colostrum and about 69% and 31% in preterm and full term milk. The mean T⁴/T⁸ ratio was higher in preterm colostrum than term colostrum, being 1.82 and 1.60 respectively. However, this difference was not significant statistically and did not change statistically in the milk sample.     

Growth and Plasma Amino Acid Concentrations in Very Low Birthweight Infants Fed Either Human Milk Protein Fortified Human Milk or a Whey-Predominant Formula

ABSTRACT. In a prospective, study involving 20 VLBW-infants (AGA), divided into two study groups of 10 infants, we have evaluated the effects on growth and metabolism of human milk fortified with ultrafiltrated human milk protein and a whey-predominant (whey/ casein = 60/40) formula containing 2 g/dl of protein. The study was initiated at a mean age of 30 days when an oral intake of 180 ml/kg/d was tolerated and continued until a weight of 2 kg was reached. The protein intake in both groups was about 3.7 g/kg/d. All infants in both groups reached intrauterine rates of growth for the age, weight gain 18.0 g/kg/d, and length 1.2 cm/week. BUN, acid-base status, total protein and albumin were normal and similar in the two groups. Plasma levels of threonine, glycine, citrulline and methionine were significantly greater in the formula-fed infants. Taurine and proline had higher concentrations in the protein fortified human milk group. There was good tolerance of protein from both sources but the differences in plasma amino acid profiles suggest that the dietary protein quality in formulas for preterm infants must be further modified, if the goal of formula feeding is to achieve metabolic indices of protein metabolism similar to those found when human milk protein is used.     

母乳中生物活性蛋白对婴儿感染的防御作用

母乳中有多种具有生物活性的蛋白质，目前研究较多的是乳铁蛋白、cathelicidin和lactadherin，这些蛋白质在胃肠道中均可抵抗蛋白酶的水解作用，主要通过直接抗病原微生物和调节免疫细胞活性及趋化免疫细胞两个方面参与对婴儿感染的防御功能，从而增强机体免疫系统对病原微生物的杀伤能力。另外，乳铁蛋白还可以通过促进肠道益生菌乳酸杆菌、双歧杆菌的生长，增强对病原微生物的抵抗能力。     

The Effect of Human Growth Hormone Injection Frequency on Linear Growth Rate

Albertsson-Wikland, K. (Departments of Paediatrics II and Physiology, University of Gothenburg, Gothenburg, Sweden). The effect of injection frequency on linear growth rate. Acta Paediatr Scand [Suppl] 337:110, 1987.
hGH has been used in the treatment of hGH deficient children for nearly 30 years. The optimum treatment regimen is, however, still unknown. Generally, administration has been by 2 or 3 intramuscular injectiodweek and the total weekly dose has been 0.3–0.5 IU/kg. Many factors are known to influence the effect of treatment, such as the dose and the age of the child. In animal studies, the optimum growth rate occurs when the physiological pulse frequency of growth hormone is simulated (i.e. intravenous infusions of growth hormone every 3 hours in the rat). In humans, optimal growth rates occur in children in whom the spontaneous secretion of hGH is associated with many peaks (pulses) of high amplitude. In hGH deficient children, growth rate increases when the weekly dose of hGH is administered daily rather than 2–3 times/week, thereby optimizing the body's utilization of the hormone. The hGH plasma profile after daily subcutaneous hGH injections is, however, different from the hGH plasma profiles of children growing normally, in whom hGH secretion is episodic with many sharp pulses during the day and night. Whether simulation of normal hGH plasma profiles will increase the growth rate in hGH deficient children and normalize their adult height requires further investigation.     

Studies of Human Milk

ABSTRACT. The concentration in human milk of IgA antibodies against six Salmonella and two Shigella groups was determined in specimens obtained from Swedish and Guatemalan nursing mothers of three different socioeconomic levels. The daily intakes of milk antibodies by their children were also estimated. The results show that the concentrations of specific IgA antibodies in milk vary among the different population groups. There is, however, no difference in daily intake of specific IgA by the children.     

Fortified High Calorie Human Milk for Optimal Growth of Low Birth Weight Babies

This study was undertaken with the aim of providing adequate calories for optimal growth in low birth weight (LBW) by fortifying human milk with medium chain triglycerides and sugar. Twenty-one LBW babies with birth weight between 1.0 and 1.75 kg and gestational age 28-36 weeks constituted the study material. They were administered expressed human milk, initially with gavage and then by spoon. Coconut oil and sugar were added to increase the caloric density to (0.8 cal/ml). The aim was to achieve a caloric intake of 200 cal/kg. This was achieved between 6 and 11 days of birth. Additionally, vitamin C (50 mg) and vitamin E (25 IU/kg/day) were administered. Weight was recorded daily to the nearest 50 g. Head circumference was measured weekly using a non-stretch tape measure. Blood urea nitrogen was measured once the neonate started taking high calorie feeds. Stools were examined daily for the presence of fat globules and reducing substances and for the pH. All but one neonate tolerated the feeds well and there were no complications, such as vomiting, diarrhoea, abdominal distension, or necrotizing enterocolitis. The weight gain recorded was 17.29 +/- 5.30 g/day or 13.95 +/- 5.52 g/kg/day. The study demonstrates that optimal growth can be achieved within the metabolic tolerance of low birth weight infants by administering fortified high calorie breast milk.     

Epidermal Growth Factor in Cow's Milk and Milk Formulas

ABSTRACT. Epidermal growth factor (EGF) in human milk, cow's milk and 10 different milk formulas was measured by radioreceptor assay (RRA) using human placental membrane as an EGF receptor. The raw and pasteurized cow's milk contained 324.2 ng/ml and 155.0 ng/ml of RRA-EGF, respectively. These values were almost the same as that found in human milk, when the concentration was expressed as the proportion of protein contents in the samples. On the other hand, no trace of RRA-EGF was detected in 9 different milk formulas, and only one contained a very small amount of it.