Newborn Gastrointestinal Tract Research Articles

Branched Chain Fatty Acid Content of United States Retail Cow's Milk and Implications for Dietary Intake

Branched chain fatty acids (BCFA) have recently been shown to be a major component of the normal human newborn gastrointestinal tract and have long been known to be a component of human milk. Ruminant food products are major sources of fat in the American diet, but there are no studies of milkfat BCFA content in retail milk. We report here the profile and concentrations of BCFA in a representative sampling of retail milk in the 48 contiguous United States (US), and their estimated intake in the American diet. Conventionally produced whole fluid milk samples were obtained from 56 processing plants across the contiguous 48 states. Retail milk samples contain exclusively iso- and anteiso-BCFA with 14-18 carbons. BCFA were 2.05±0.14%, w/w of milkfat fatty acids (mean±SD), and anteiso-BCFA comprised more than half this total. Based on these data and USDA food availability data, the average per capita BCFA intake of Americans is estimated to be about 220mg/d from dairy; if current dietary recommendations were followed, BCFA intake would be about 400mg/d. Adding intake from beef consumption, these estimates rise to approximately 400 and 575mg/d, respectively. These results indicate that BCFA intake is a substantial fraction of daily fat intake, in amounts exceeding those of many bioactive fatty acids.

Branched Chain Fatty Acids Are Constituents of the Normal Healthy Newborn Gastrointestinal Tract

Vernix suspended in amniotic fluid is normally swallowed by the late term fetus. We hypothesized that branched chain fatty acids (BCFA), long known to be major vernix components, would be found in meconium and that the profiles would differ systematically. Vernix and meconium were collected from term newborns and analyzed. BCFA-containing lipids constituted about 12% of vernix dry weight, and were predominantly saturated, and had 11-26 carbons per BCFA. In contrast, meconium BCFA had 16-26 carbons, and were about 1% of dry weight. Meconium BCFA were mostly in the iso-configuration, whereas vernix BCFA contained dimethyl and middle chain branching, and five anteiso-BCFA. The mass of BCFA entering the fetal gut as swallowed vernix particles is estimated to be 180 mg in the last month of gestation whereas the total mass of BCFA found in meconium is estimated to be 16 mg, thus most BCFA disappear from the fetal gut. The BCFA profiles of vernix and meconium show that BCFA are major components of normal healthy term newborn gastrointestinal tract. BCFA are candidates for agents that play a role in gut colonization and should be considered a nutritional component for the fetus/newborn.

Microbes Colonize a Baby’s Gut with Distinction

Microbes Colonize a Baby’s Gut with Distinction

Limited proteolysis of the IGF binding protein-2 (IGFBP-2) by a specific serine protease activity in early breast milk.

IGF in milk possibly promote maturation of the gastrointestinal tract in newborns. We studied the composition of milk samples derived from 99 healthy women at regular intervals during a period beginning 3 d and ending 6 mo after birth. The concentrations measured by RIA on d 3 were 10.7+/-0.4 ng/mL for IGF-II, 1.9+/-0.1 ng/mL for IGF-I, 100+/-5 ng/mL for IGF binding protein-3 (IGFBP-3), and 2163+/-108 ng/mL for IGFBP-2. All factor concentrations decreased by up to 70% in the course of the 6 mo. The most striking finding was an IGFBP-2-specific protease activity. Protease assays performed by incubation of 125I-IGFBP-2 with milk yielded fragments of 14, 16, 23, and 25 kD. 125I-IGFBP-3 was not cleaved. Proteolysis occurred only in milk from mothers until 4 wk postpartum and could be visualized by immunoblots. Since the affinity of the fragments to 125I-IGF-II was low, they were not demonstrable by ligand blot. Inhibitor studies and pH optimizing classified the IGFBP-2 protease as an Me2(+)-dependent serine protease with a pH optimum of 7 to 8. The proteolytic activity of further milk proteins, known as IGFBP proteases, was analyzed. Epidermal growth factor receptor peptide and prostate-specific antigen did not cleave IGFBP-2, although the protease activity correlated (r = 0.84, p < 0.00003) with the prostate-specific antigen concentration in milk. The y-nerve growth factor cleaved 125I-IGFBP-2, but in a completely different manner than the milk protease. In conclusion, the IGFBP-2 protease in milk is most probably a kallikrein. The specific proteolysis of IGF/IGFBP-2 complexes may increase the biologic availability of IGF in early milk. This mechanism may promote growth of the maternal breast epithelium and maturation of the gastrointestinal tract of newborns.

Detection and Characterisation of Transforming Growth Factor-Beta in Porcine Colostrum

Porcine colostrum and milk collected at different stages of lactation were assessed for transforming growth factor-β (TGF-β) activity using an epithelial cell bio-assay. A high level of TGF-β activity was recorded in all colostrum samples after transient acidification treatment, ranging between 126 and 260 ng/ml for samples collected at the time of parturition and 73 ng/ml for the sample collected 12 h after parturition. Without transient acidification treatment TGF-β activity was detected only in 2 samples collected at the time of parturition (12 ng/ml) and 12 h after parturition (9 ng/ml), respectively. TGF-β activity was undetectable in milk collected 5 days after parturition. These results suggest that TGF-β exists mainly in latent form in porcine colostrum and the concentration declines rapidly as lactation proceeds. After enrichment with cation exchange chromatography a low level of TGF-β activity was detected in porcine milk. Further separation by size exclusion chromatography revealed two molecular mass forms of TGF-β in both colostrum and milk samples, a major peak of about 80 kD and a minor peak of about 25 kD representing latent and active forms of TGF-β, respectively. A further experiment showed that the latent form of TGF-β in colostrum can be activated at pH 3.5 or less. It is speculated that TGF-β found in the colostrum may play a physiological role in regulating postnatal adaptation of the gastro-intestinal tract in newborns.

Do Hormones in Milk Affect the Function of the Neonatal Intestine?

The presence of a number of peptide hormones and other biologically active peptides (BAP) in the milk of various species, together with the low proteolytic activity in the gastrointestinal tract of newborns and “permeability” for macromolecules, suggests theirpotential significance for the neonate I review the presence of hormones and other biologically active peptides (BAP) in milks of various species. Furthermore, I summarize data demonstrating the effects of orogastrically administered BAP with special attention to epidermal growth factor.

Alendronate: The relation between skeltal retention and supression of bone resorption

Several peptide hormones and growth factors have been found in human milk, and we present here the results of measurements of parathyroid hormone-related peptide (PTHrP). A radioimmunoassay (RIA) using a polyclonal antiserum against the mid-region of the molecule has been developed. In milk collected during the first 6 days after parturition, the PTHrP concentrations showed large interindividual variations ranging from 0.3 to 13.7 nmol-Eq/L (0.5 to 24.4 ng-Eq/mL) (n = 67) and increased between days 3 and five postpartum. PTHrP also increased during the first 4 collecting days when measured in milk from the same mother during a prolonged period. On fast-protein liquid chromatography (FPLC), the bulk of PTHrP eluted with a molecular weight of approximately 10 to 12 kd after treatment with urea. After mid-molecule immunoaffinity extraction of PTHrP from milk, higher levels were obtained by the mid-molecule RIA than by an aminoterminal assay, indicating that all fragments did not contain the aminoterminal. Parts of immunoextracted milk PTHrP stimulated cyclic adenosine monophosphate (cAMP) production in rat osteosarcoma cell line, UMR-106. In conclusion, we have found PTHrP-like immunoreactivity in human milk using a mid-region RIA. Parts of the immunoextracts also contained the aminoterminal and possessed PTH-like bioactivity. Whether PTHrP in human milk plays a physiological role in the maternal breast or in the newborn gastrointestinal tract is unknown, but the present observations demonstrate that a portion of the PTHrP is at least potentially biologically active.

Parathyroid hormone-related peptide in human milk measured by a mid-molecule radioimmunoassay

Several peptide hormones and growth factors have been found in human milk, and we present here the results of measurements of parathyroid hormone-related peptide (PTHrP). A radioimmunoassay (RIA) using a polyclonal antiserum against the mid-region of the molecule has been developed. In milk collected during the first 6 days after parturition, the PTHrP concentrations showed large interindividual variations ranging from 0.3 to 13.7 nmol-Eq/L (0.5 to 24.4 ng-Eq/mL) (n = 67) and increased between days 3 and five postpartum. PTHrP also increased during the first 4 collecting days when measured in milk from the same mother during a prolonged period. On fast-protein liquid chromatography (FPLC), the bulk of PTHrP eluted with a molecular weight of approximately 10 to 12 kd after treatment with urea. After mid-molecule immunoaffinity extraction of PTHrP from milk, higher levels were obtained by the mid-molecule RIA than by an aminoterminal assay, indicating that all fragments did not contain the aminoterminal. Parts of immunoextracted milk PTHrP stimulated cyclic adenosine monophosphate (cAMP) production in rat osteosarcoma cell line, UMR-106. In conclusion, we have found PTHrP-like immunoreactivity in human milk using a mid-region RIA. Parts of the immunoextracts also contained the aminoterminal and possessed PTH-like bioactivity. Whether PTHrP in human milk plays a physiological role in the maternal breast or in the newborn gastrointestinal tract is unknown, but the present observations demonstrate that a portion of the PTHrP is at least potentially biologically active.

The rediscovery of infant feeding formula with magnetic resonance imaging

In six newborns, regular infant feeding formula given approximately one-half hour to four hours prior to MR examination, demonstrated a high intensity signal within the infant's stomach, small bowel, and colon. This effect was observed on both 0.5 Tesla and 1.5 Tesla magnets on T1 (SE TR/TE 433-600/20-25) and on T2 (SE TR/TE 1500/30-80) weighted images. Infant feeding formula has the potential to be used as an oral contrast agent for visualization of the newborn gastrointestinal tract. Chloral hydrate and other agents were also tested.

Bacterial colonization of the large intestine in newborns delivered by Cesarean section

Colonization of the gastrointestinal tract in newborns delivered by Cesarean section occurs during the first days of life by bacteria provided by the environment. It is more rapid in breast-fed infants than in bottle-fed babies. The intestinal flora is more diversified if the infants receive formula feeding. The first bacteria encountered are facultative anaerobes; they remain predominant during the first two weeks of life. In comparison to vaginal delivery, there were low levels of strict anaerobes after Cesarean section; members of the Bacteroides fragilis group were still completely lacking after 14 days of life and Bifidobacteria were only isolated sporadically.

The age-dependence of intestinal absorption using d-xylose as an example.

In 40 infants the serum concentrations of D-xylose were measured from capillary blood samples up to 300 min after an oral dosage of 0.5 g of D-xylose per kg body weight. The parameters of the absorption kinetics, which are calculated by a digital computer program, showed an age-dependent behavior. Infants up to the age of 2 months have lower maximal serum concentrations compared to older ones because of a larger volume of distribution. The rate constant of invasion k1, which serves as a measure for the rate of intestinal absorption and the rate constant of elimination k2 were significantly lower in infants up to the age of 2 months compared to older ones. The quotient of k1:k2 was independent of age. The time it took to reach maximal serum concentration was significantly longer in young infants. By adding metoclopramide simultanously to the oral D-xylose doses it could be demonstrated that the slower motility of the gastrointestinal tract in newborns and young infants is not exclusively responsible for the slower rate of absorption of D-xylose. Comparing the absorption rates in 26 infants after different D-xylose dosages a saturation kinetics may be supposed.

Adventitious deposition of iodized oil in middle ear.

IODIZED oil (Lipiodol) has been used by us as an opaque medium for the visualization of the esophagus and the gastrointestinal tract in newborns and infants. It has been observed by others as well as ourselves that the medium is frequently aspirated into the trachea and bronchial tree.* We have been observing a patient for one and one-half years in whom radiopaque particles were found in the right middle ear and mastoid region following a gastrointestinal series which was done with iodized oil. We have found no other similar case in the literature. REPORT OF A CASE L. S. (220907), a girl, was born in Bronx Hospital Oct. 4, 1952, after a difficult delivery. Soon after birth the child exhibited muscular rigidity and was noted to regurgitate and vomit. Because partial intestinal obstruction was suspected, a gastrointestinal series with iodized oil was done. Subsequent to this, roentgenograms of the skull