The piglet as a model for studying dietary components in infant diets: effects of galacto-oligosaccharides on intestinal functions.

Prebiotic oligosaccharides, including galacto-oligosaccharides (GOS), are used in infant formula to mimic human milk oligosaccharides, which are known to have an important role in the development of the intestinal microbiota and the immune system in neonates. The maturation of the intestines in piglets closely resembles that of human neonates and infants. Hence, a neonatal piglet model was used to study the multi-faceted effect of dietary GOS in early life. Naturally farrowed piglets were separated from the mother sow 24-48 h postpartum and received a milk replacer with or without the addition of GOS for 3 or 26 d, whereafter several indicators of intestinal colonisation and maturation were measured. Dietary GOS was readily fermented in the colon, leading to a decreased pH, an increase in butyric acid in caecum digesta and an increase in lactobacilli and bifidobacteria numbers at day 26. Histomorphological changes were observed in the intestines of piglets fed a GOS diet for 3 or 26 d. In turn, differences in the intestinal disaccharidase activity were observed between control and GOS-fed piglets. The mRNA expression of various tight junction proteins was up-regulated in the intestines of piglet fed a GOS diet and was not accompanied by an increase in protein expression. GOS also increased defensin porcine ß-defensin-2 in the colon and secretory IgA levels in saliva. In conclusion, by applying a neonatal piglet model, it could be demonstrated that a GOS-supplemented milk replacer promotes the balance of the developing intestinal microbiota, improves the intestinal architecture and seems to stimulate the intestinal defence mechanism.

Comparison of milk oligosaccharides pattern in colostrum of different horse breeds.

Colostrum oligosaccharides are known to exhibit prebiotic and immunomodulatory properties. Oligosaccharide composition is species-specific, and equine colostrum has been reported to contain unique oligosaccharides. Therefore, equine oligosaccharides (EMOS) from colostrum from different horse breeds were analyzed by CE-LIF, CE-MS(n), HILIC-MS(n), and exoglycosidase degradation. Sixteen EMOS were characterized and quantified, of which half were neutral and half were acidic. EMOS showed about 63% structural overlap with human milk oligosaccharides, known for their bioactivity. Seven EMOS were not reported before in equine oligosaccharides literature: neutral Gal(ß1-4)HexNAc, Gal(ß1-4)Hex-Hex, ß4'-galactosyllactose, and lactose-N-hexaose, as well as acidic 6'-Sialyl-Hex-Ac-HexNAc, sialyllacto-N-tetraose-a, and disialylacto-N-tetraose (isomer not further specified). In all colostrum samples, the average oligosaccharide concentration ranged from 2.12 to 4.63 g/L; with ß 6'and 3'- galactosyllactose, 3'-sialyllactose, and disialyllactose as the most abundant of all oligosaccharides (27-59, 16-37, 1-8, and 1-6%, respectively). Differences in presence and in abundance of specific EMOS were evident not only between the four breeds but also within the breed.

Oligosaccharides in goat milk: structure, health effects and isolation.

Oligosaccharides have been widely recognized for their prebiotic and anti-infective properties. Among the different types of mammalian milk, the one of humans is the richest source of naturally derived oligosaccharides. However, their use as a basis for functional foods is hampered, due to their structural complexity, which in turn makes their re-synthesis extremely difficult. Thus, oligosaccharides from other sources have to be used. In this sense, goat milk constitutes a very appealing candidate, as it contains the highest amount of oligosaccharides among domestic animals, while goat milk oligosaccharides show significant similarities to human milk oligosaccharides from a structural point of view. Studies on goat milk oligosaccharides are scant, and more data is required in order to provide solid clinical evidence of their beneficial effects on humans. The aim of this review is to collect and present the main research findings on goat milk oligosaccharides structure, health effects and isolation.

Application of a lumped-process mathematical model to dissolution of non-uniformly distributed immiscible liquid in heterogeneous porous media.

The use of a lumped-process mathematical model to simulate the complete dissolution of immiscible liquid non-uniformly distributed in physically heterogeneous porous-media systems was investigated. The study focused specifically on systems wherein immiscible liquid was poorly accessible to flowing water. Two representative, idealized scenarios were examined, one wherein immiscible liquid at residual saturation exists within a lower-permeability unit residing in a higher-permeability matrix, and one wherein immiscible liquid at higher saturation (a pool) exists within a higher-permeability unit adjacent to a lower-permeability unit. As expected, effluent concentrations were significantly less than aqueous solubility due to dilution and by-pass flow effects. The measured data were simulated with two mathematical models, one based on a simple description of the system and one based on a more complex description. The permeability field and the distribution of the immiscible-liquid zones were represented explicitly in the more complex, distributed-process model. The dissolution rate coefficient in this case represents only the impact of local-scale (and smaller) processes on dissolution, and the parameter values were accordingly obtained from the results of experiments conducted with one-dimensional, homogeneously-packed columns. In contrast, the system was conceptualized as a pseudo-homogeneous medium with immiscible liquid uniformly distributed throughout the system for the simpler, lumped-process model. With this approach, all factors that influence immiscible-liquid dissolution are incorporated into the calibrated dissolution rate coefficient, which in such cases serves as a composite or lumped term. The calibrated dissolution rate coefficients obtained from the simulations conducted with the lumped-process model were approximately two to three orders-of-magnitude smaller than the independently-determined values used for the simulations conducted with the distributed-process model. This disparity reflects the difference in implicit versus explicit consideration of the larger-scale factors influencing immiscible-liquid dissolution in the systems.

Mass-removal and mass-flux-reduction behavior for idealized source zones with hydraulically poorly-accessible immiscible liquid.

A series of flow-cell experiments was conducted to investigate aqueous dissolution and mass-removal behavior for systems wherein immiscible liquid was non-uniformly distributed in physically heterogeneous source zones. The study focused specifically on characterizing the relationship between mass flux reduction and mass removal for systems for which immiscible liquid is poorly accessible to flowing water. Two idealized scenarios were examined, one wherein immiscible liquid at residual saturation exists within a lower-permeability unit residing in a higher-permeability matrix, and one wherein immiscible liquid at higher saturation (a pool) exists within a higher-permeability unit adjacent to a lower-permeability unit. The results showed that significant reductions in mass flux occurred at relatively moderate mass-removal fractions for all systems. Conversely, minimal mass flux reduction occurred until a relatively large fraction of mass (>80%) was removed for the control experiment, which was designed to exhibit ideal mass removal. In general, mass flux reduction was observed to follow an approximately one-to-one relationship with mass removal. Two methods for estimating mass-flux-reduction/mass-removal behavior, one based on system-indicator parameters (ganglia-to-pool ratio) and the other a simple mass-removal function, were used to evaluate the measured data. The results of this study illustrate the impact of poorly accessible immiscible liquid on mass-removal and mass-flux processes, and the difficulties posed for estimating mass-flux-reduction/mass-removal behavior.

Creating a human phantom for the virtual human program.

A high-resolution human phantom--a computer representation of the human anatomy--is needed as part of the Virtual Human (VH) simulation environment being developed by Oak Ridge National Laboratory and collaborators. Within the VH environment, this 3D anatomical phantom is coupled with physiological models and data to investigate a wide range of human biological and physical responses to stimuli. This paper describes how the phantom was created using the Visible Human (male) image data from the U.S. National Library of Medicine. Initially, X-ray computed tomography (CT) as well as photographic images of the Visible Human (male) torso were segmented and classified with software developed using IDL. From these data, non-uniform, rational B-spline (NURBS) spatial models were fitted to represent the surfaces of discrete body structures such as bones and organs. This collection of NURBS models, referred to as the NURBS VH, defines the fundamental Virtual Human phantom. The NURBS VH is compatible with modeling and animation software, enabling dynamic manipulation of body structures and their associated visual representations. The organization of the structural data lends itself to existing and evolving Web and electronic communication standards, making it attractive for applications such as medical training. In addition, finite-element (FE) meshes were created from the NURBS VH for use in trauma simulation, electromagnetic field exposure modeling, dosimetry, and other applications requiring spatially-defined tissue properties. The ability to scale the NURBS VH to account for age and size and the ability to easily animate NURBS objects yield a very flexible human phantom for the VH simulation environment.