In 41 healthy human-milk-fed preterm infants the preprandial total bile acid (B A) concentrations in serum and duodenal juice were simultaneous measured during the first 60 days of life. The infants were subdivided into four groups according to their gestational age: 6 infants with a gestational age of 27 and 28 weeks, 7 infants with a gestational age of 29 and 30 weeks, 21 infants with a gestational age of 31 and 32 weeks and 7 infants with a gestational age of 33 and 34 weeks. The BA levels were enzymatically determined using 3-α-hydroxysteroid dehydrogenase. In the duodenal juice, cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid and lithocholic acid were separately quantified by thin-layer chromatography. During the first month of life, the serum BA concentrations increased significantly with postnatal age (p < 0.01) but remained nearly constant during the second month of life. In the duodenal aspirates, the BA concentrations increased continuously up to the end of the observation period (p < 0.001). In the duodenal aspirates, the CA/CDCA ratio was high immediately after birth and decreased significantly with increasing postnatal age (p < 0.001). During the first weeks of life, the BA levels were preferentially conjugated with taurine, but in spite of the taurine-rich diet during the whole observation period the taurine/glycine ratio decreased with postnatal age (p < 0.001). In all samples of duodenal juice, the sum of primary BA was > 98% of total 3-α-hydroxy-BA. These data indicate that the establishment of an intestinal microbial flora necessary for intestinal BA transformation and the development of the enterohepatic BA circulation lasts some months of postnatal life. The serum BA concentration reflects hepatic synthesis, intestinal absorption, renal excretion and hepatocellular transport into bile in a very complex way which may limit the diagnostic value of serum BA during this time. Additionally, a duodenal BA concentration below 4 mmol/l, as found in this study during the first 2 weeks of life, may be of clinical importance due to its possible effects on fat absorption.

Metabolic response to human milk feeding was studied in 12 appropriate (AGA) and 12 small for gestational age (SGA) infants of very low birthweight (VLBW) on the eighth day of life. Protein intake ranged from 1.98 to 2.47 g/kg/day and caloric intake from 94 to 126 kcal/kg/day with no significant differences between the groups. Alpha-amino-nitrogen, the total bile acid concentration in serum and total- as well as alpha-amino-nitrogen excretion in the urine were estimated. The alpha-amino-nitrogen and the total bile acid concentration in serum increased with increasing degree of intrauterine growth retardation. Also renal total- and alpha-amino-nitrogen excretion increased significantly in relation to the degree of intrauterine growth retardation. Thus, despite a relatively low protein intake in severely growth retarded VLBW-infants, metabolic changes could be found similar to those observed in AGA-infants on high protein intakes. The data suggest that during the first weeks of postnatal life VLBW-infants with intrauterine growth retardation have a decreased capacity to utilize or to metabolize protein when compared to AGA-infants with comparable birthweights. These metabolic differences have to be considered in the nutritional management of VLBW-infants.

Aqueous suspensions of glutaraldehyde cross-linked fibrillar collagen and non-cross-linked fibrillar collagen were examined by rheometry, particle size analysis, and microscopic techniques. Although cross-linked collagen suspensions were similar to non-cross-linked suspensions by microscopic and size analyses, they differed in rheometric properties. Concentric cylinder Couette flow, shear creep, uniaxial creep, and porous bed flow all revealed that cross-linked collagen was more resistant to deformation and flow than non-cross-linked collagen. These results were in agreement with in vivo dermal implantation studies, both in pig and human; i.e., compared to non-cross-linked collagen, the cross-linked formulation was more difficult to inject into tissue and did not spread uniformly, sometimes giving rise to palpable lumps or large masses evident in histological sections. When hyaluronic acid was blended with cross-linked collagen to achieve a final hyaluronate concentration of 5 mg/mL, there was a significant improvement in ease of injection into tissue. Rheometry on blends of hyaluronate and cross-linked collagen demonstrated that the blend required lower forces to achieve deformation and flow, compared to cross-linked collagen alone. Particle size analysis on the blend showed a reduction in fiber aggregate dimensions, compared to cross-linked collagen alone.

No abstract

In the present investigation 32 very-low-birth-weight (VLBW) infants fed at three different levels of protein intake (2.92 g/kg/d from human milk, 3.22 and 4.06 g/kg/d from formula) were studied at the mean age of 21 days. Serum total alpha-amino nitrogen concentration correlated directly to total bile acid concentration. The serum and urine alpha-amino nitrogen and the serum bile acid concentration correlated with protein intake. The increase in protein intake was accompanied by a concomitant decrease in the intraluminal bile acid concentration in the AGA infants. The results offer indirect evidence of decreased bile flow in VLBW-infants on excessive oral protein intake. The cholestatic effect could be mediated by an increase in the plasma amino acid concentration.