Biomedical subjects
Publications and source records attributed to P McVeagh.
We found that the saliva of preterm infants fed human milk contains twice the level of sialic acid as that in infants fed commercial formulas. The higher sialic acid level suggests greater viscosity and enhanced protection of the mucosal surfaces in breast-fed infants. Human milk itself is a rich source of sialylated oligosaccharides.
BACKGROUND: In animal studies, sialic acid supplementation is associated with increases of gangliosides in the brain and improved learning ability. Only limited data are available on the sialic acid content of human milk and infant formulas. OBJECTIVE: We compared the concentrations of oligosaccharide-bound, protein-bound, and free sialic acid in milk from mothers of full-term and preterm infants and in a range of infant formulas. DESIGN: The milk from 20 and 14 mothers of full-term and preterm infants (mean gestational age: 31 +/- 3 wk), respectively, was collected at 4 stages of lactation (colostrum, transition, 1 mo, and 3 mo) and compared with 21 different infant formulas. RESULTS: Total sialic acid concentrations were highest in colostrum (x +/- SEM: 5.04 +/- 0.21 mmol/L in full term) and decreased by nearly 80% over the next 3 mo. Human milk from mothers of preterm infants contained 13-23% more sialic acid than did milk from mothers of full-term infants at 3 of the 4 lactation stages (P < 0.02). The sialic acid content of most formulas was <25% of that found in mature human milk (P < 0.01). Most of the sialic acid in the formulas ( approximately 70%) was bound to glycoproteins, whereas in human milk most sialic acid was bound to free oligosaccharides. CONCLUSIONS: Human milk, including milk from mothers of preterm infants, is a rich source of oligosaccharide-bound sialic acid, which contrasts with the relatively small amounts found in infant formulas. The nutritional significance of sialic acid is presently unknown, but it is plausible that it is a conditional nutrient that contributes to sialic acid accretion in the brain.
BACKGROUND: In Australia good food is abundant and relatively cheap but childhood obesity is increasing and many children are offered suboptimal nutrition. OBJECTIVE: The impediments to healthy food choices and strategies for promoting a healthy diet in childhood are discussed. DISCUSSION: Good nutrition in childhood is important, not only for the health, growth and development of the child but also for long term health. A child's energy requirement can easily be met from snack food, at the expense of more nutrient rich foods. There are no 'good' or 'bad' foods: it is the overall package of intake that is important. Children need to be offered a variety of nutrient rich foods at regular times during the day.
Explore the source record for details and available documents.
OBJECTIVE: We hypothesized that human milk oligosaccharides (HMO) would not be digested and absorbed in the infant small intestine. The purpose of the study was to quantify the extent of digestion by using the lactulose breath hydrogen test. STUDY DESIGN: Twenty-four healthy, breast-fed infants were studied in the home setting. Eight infants (mean age 5.2 months) who had a positive breath hydrogen response (rise > 20 ppm) to the unabsorbable sugar lactulose were given an equivalent load of HMO (0.7 to 1.0 gm/kg body weight) the following week. The breath hydrogen response to the HMO load was compared with that after lactulose by using a paired t test. RESULTS: In seven of the eight infants, a large proportion of the HMO load reached the large intestine and was fermented. In these infants, the mean +/- SEM area under the breath hydrogen curve after HMO (5135 +/- 1148 ppm.4h) was not significantly different from that after lactulose (4949 +/- 1278 ppm.4h, p = 0.7s. CONCLUSIONS: This study suggests that HMO resist digestion in the small intestine of most breast-fed infants and undergo fermentation in the colon. HMO may therefore be the source of breath hydrogen in breast-fed infants.
Sialic acid is a vital component of brain gangliosides which play an essential role in the transmission and storage of information in the brain. The concentration of bound sialic acid in gangliosides and free sialic acid in the brain cortex of eight different mammals [human, chimpanzee (Pan troglodytes), rat (Rattus norvegicus), mouse (Mus musculus), rabbit (Oryctolagus cuniculus), sheep (Ovis aries), cow (Bos indicus) and pig (Sus scrofa)] were compared. Total sialic acid concentration (890+/-103 microg/g wet weight tissue, mean+/-SE, n = 6) was 2-4 times higher in the human brain compared with the other species studied (0.001 < p < 0.05). There was no significant difference between human males and females. The rank order of adult brain sialic acid after humans (in microg/g) was rat (493+/-23, n = 12), mouse (445+/-29, n = 16), rabbit (380+/-18, n = 6), sheep (323+/-43, n = 6), cow (304+/-14, n = 6) and pig (252+/-14, n = 6). Apart from the cow vs the sheep, the differences between species were statistically significant (p < 0.05). In the mouse, cow and sheep, total sialic acid concentration increased during maturation by 18-32% (p < 0.05). In a 2-year-old chimpanzee, the sialic acid concentration in the left lobe of the brain cortex was 25% higher than that of right lobe at 6 weeks of age (p < 0.05). Free sialic acid was higher in the human brain cortex (41+/-3 microg/g) than that of the rat and mouse (32+/-3 and 25+/-5 microg/g respectively) and absent from other species. Variation in brain sialic acid concentration among different animals has implications for the evolution of the brain and may affect learning ability in animals.
Over 100 years ago it was first deduced that a major component of human milk must be an unidentified carbohydrate that was not found in cows milk. At first this was thought to be a form of lactose and was called gynolactose. We now know that this was not a single carbohydrate but a complex mixture of approximately 130 different oligosaccharides. Although small amounts of a few oligosaccharides have been found in the milk of other mammals, this rich diversity of sugars is unique to human milk. The oligosaccharide content of human milk varies with the infant's gestation, the duration of lactation, diurnally and with the genetic makeup of the mother. Milk oligosaccharides have a number of functions that may protect the health of the breast fed infant. As they are not digested in the small intestine, they form the 'soluble' fibre of breast milk and their intact structure is available to act as competitive ligands protecting the breast-fed infant from pathogens. There is a growing list of pathogens for which a specific oligosaccharide ligand has been described in human milk. They are likely to form the model for future therapeutic and prophylactic anti-microbials. They provide substrates for bacteria in the infant colon and thereby contribute to the difference in faecal pH and faecal flora between breast and formula-fed infants. They may also be important as a source of sialic acid, essential for brain development.
Sialic acid is found in especially high concentrations in brain gangliosides, and supplementary sialic acid is associated with increased learning behaviour in animals. It was hypothesised that breast fed infants may have higher concentrations of sialic acid in body fluids and tissues because human milk is a rich source of sialylated oligosaccharides, while formulas contain very little. The aim therefore was to compare the sialic acid content of saliva collected from full term infants who were either solely breast fed or formula fed until weaning at 3-5 months of age. Thirty three infants, 18 breast fed and 15 formula fed, were studied at a mean (SD) age of 5 (2) months. The breast fed infants, when compared with formula fed infants, were found to have almost two times more free sialic acid in saliva (mean (SE) 16.0 (2.7) v 8.2 (2.1) mg/l, p < 0.036) and nearly 50% more total sialic acid (47.3 (3.9) v 32.2 (4.4) mg/l, p < 0.014). The findings provide a preliminary indication that an exogenous source of sialic acids derived from human milk may contribute to higher concentrations of sialic acid in body fluids. There are important implications for the formulation of human milk substitutes.
Oligosaccharides are an important component of human milk, but little is known about variations in their composition. The aim of this study was to determine the temporal and inter-individual variations in carbohydrate composition of human milk during the first 3 months of lactation. Serial milk samples of 10 mothers (eight full-term and two preterm births) were analyzed to determine the concentration of lactose and three monosaccharide components derived from the non-lactose carbohydrate: sialic acid, N-acetylglucosamine, and fucose. In full-term milk, sialic acid and N-acetylglucosamine were found to decrease significantly (p < 0.05) from weeks 1 to 13 postnatally. On average (mean +/- SD), sialic acid decreased by 71% (from 879 +/- 157 to 256 +/- 82 mg/L; p < 0.05) and N-acetylglucosamine by 56% (from 1,459 +/- 282 to 646 +/- 214 mg/L; p < 0.05), while fucose decreased by only 35% (from 660 +/- 192 to 432 +/- 180 mg/L; p > 0.05). On average, lactose concentration increased by 17% over the same period, from 55.4 +/- 4.2 g/L in week 1 to 64.9 +/- 2.3 g/L at 3 months. Preterm milk contained higher concentrations of each component, but temporal changes were similar to those seen in full-term milk. Apart from temporal changes, there were large inter-individual differences in oligosaccharide composition: fucose varied four-fold, sialic acid threefold, and N-acetylglucosamine two-fold among women at the same stage of lactation. The changes observed may simply reflect the aging of the cells responsible for milk secretion, but they are also consistent with a programmed adaptation of the milk composition to the needs of the infant.
Breath hydrogen excretion was measured serially in breast-fed infants. There was marked variability in H2 excretion, both within and between infants. The findings indicate that unabsorbed food is not the only substrate, and that breath H2 may not be an effective method to assess carbohydrate absorption in young infants.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Breath hydrogen excretion as an index of incomplete lactose absorption was measured in 118 healthy infants who were either breast fed or given a formula feed containing lactose, some of whom had colic. Infants with colic (n = 65) were selected on the basis of the mother's report of a history of inconsolable crying lasting several hours each day. Infants in the control group (n = 53) were not reported to cry excessively by their mothers. Breath samples were collected using a face mask sampling device preprandially, and 90 and 150 minutes after the start of a feed. Normalised breath hydrogen concentrations were higher in the group with colic than in the control group at each time point. The median maximum breath hydrogen concentration in the colic group was 29 ppm, and in the control group 11 ppm. The percentage of infants with incomplete lactose absorption (breath hydrogen concentration more than 20 ppm) in the colic group was 62% compared with 32% in the control group. The clinical importance of the observed association between increased breath hydrogen excretion and infantile colic remains to be determined. Increased breath hydrogen excretion indicative of incomplete lactose absorption may be either a cause or an effect of colic in infants.
We have examined the use of radionuclide milk scanning to detect aspiration and have compared the clinical features of patients with demonstrated aspiration with those of patients in whom aspiration was not demonstrated. One hundred twenty children underwent radionuclide milk scanning for three different clinical indications, namely, respiratory tract symptoms (n = 56), gastroesophageal (GO) reflux (n = 20), and near-miss sudden infant death syndrome (SIDS) (n = 44). Ninety-eight (82%) of the 120 patients had a GO reflux demonstrated on the radionuclide milk scan. The incidence of aspiration was high in the respiratory (23%) and near-miss SIDS groups (20%) but low in the GO reflux group (5%). Only four of the 19 patients with an aspiration-positive scan had an aspiration-positive barium swallow film. The clinical symptoms and signs of those patients with aspiration-positive results were not significantly different from those of patients in whom aspiration was not demonstrated. We conclude that radionuclide milk scanning is more sensitive than barium swallow roentgenography in detecting aspiration; however, the clinical significance of such aspiration is undetermined. In view of the high incidence of GO reflux demonstrated in the absence of aspiration by the use of radionuclide milk scanning, the sole finding of GO reflux in a child with respiratory tract symptoms should not be taken as presumptive evidence that aspiration is contributing to those symptoms.
To determine the association between inhalation and increased circulating milk antibodies, the presence of milk precipitins and haemagglutinating titres of antibody to casein and lactalbumin were determined in a series of 100 children studied by radionuclide 'milk scan' and/or barium swallow for possible milk inhalation. Sixty-five were investigated because of reflux and/or inhalation (REFLUX), while 35 were evaluated after near-miss sudden infant death (SID). Inhalation was demonstrated in 23/65 Reflux and 9/35 Sid patients. The incidence of milk precipitins was 22% (5/23) of the REFLUX with demonstrable inhalation, 12% (5/42) of the REFLUX without demonstrable inhalation, 0% (0/23) SID and 2% (21/1005) of an unselected series of hospital patient sera. The incidence of milk precipitins was increased in cases with demonstrated inhalation and lower respiratory tract symptoms. Determination of antibody titres to casein and lactalbumin did not provide additional benefit in the diagnosis of milk inhalation. Detection of milk precipitins can provide additional support to the diagnosis of milk inhalation.
A patient with haemophilia and antibodies to factor VIII was treated with activated prothrombin concentrate (PPSB). Clinical manifestations of haemophilia subsided after treatment with PPSB, and the prolonged partial thromboplastin time shortened temporarily. There were no untoward side effects of the treatment.
Two children developed hepatotoxicity during treatment for right-sided Wilms Tumor. Treatment consisted of nephrectomy, irradiation, and chemotherapy with actinomycin D and vincristine. Hepatic enlargement, thrombocytopenia, and abnormalities in liver function and seen on the liver scan occurred at the time of the course of chemotherapy administered 20 days after completion of irradiation. These abnormalities disappeared when treatment was temporarily suspended. Vincristine and actinomycin D were subsequently reintroduced without evidence of hepatotoxicity. Actinomycin D after irradiation for right-sided Wilms tumor may produce severe liver toxicity.