Galacto-Oligosaccharides : production, properties, applications, and significance as prebiotics

Galacto-oligosaccharides (GOS) have now been definitely established as prebiotic ingredients after in vitro and animal and human in vivo studies. Currently, GOS are produced by glycoside hydrolases (GH) using lactose as substrate. Converting lactose into GOS by GH results in mixtures containing GOS of different degrees of polymerization (DP), unreacted lactose, and monomeric sugars (glucose and galactose). Recent and future developments in the production of GOS aim at delivering purer and more efficient mixtures. To produce high-GOS-content mixtures, GH should not only have good ability to catalyze the transgalactosylation reaction relative to hydrolysis, but also have low affinity for the GOS formed relative to the affinity for lactose. In this article, several microbial GH, proposed for the synthesis of GOS, are hierarchized according to the referred performance indicators. In addition, strategies for process improvement are discussed. Besides the differences in purity of GOS mixtures, differences in the position of the glycosidic linkages occur, because different enzymes have different regiochemical selectivity. Depending on oligosaccharide composition, GOS products will vary in terms of prebiotic activity, as well as other physiological effects. This review focuses on GOS production from synthesis to purification processes. Physicochemical characteristics, physiological effects, and applications of these prebiotic ingredients are summarized. Regulatory aspects of GOS-containing food products are also highlighted with emphasis on the current process of health claims evaluation in Europe.Agência da Inovação-Progama IDEIA (Portugal)Fundação para a Ciência e a Tecnologia (FCT

Multispectral system evaluates treatments in dermatology

An advanced multispectral dermatoscope can be used to study changes in the macroscopic structure of the skin. The system produces detailed images that can be used to track skin changes over time

The effect of zirconia and titanium implant abutments on lightreflection of the supporting soft tissues

Objectives: To determine the difference in light reflection of oral mucosa covering titanium (Ti) or zirconia (ZrO2) abutments as it relates to the thickness of the covering mucosa. Material and methods: Fifteen anterior implants (Astra Osseo speed (R)) in 11 patients were fitted with a Ti or a ZrO2 abutment (cross-over, within-subject comparison). Hyper-spectral images were taken with a camera fitted on a surgical microscope. High-resolution images with 70nm interval between 440 and 720 nm were obtained within 30 s (1392 x 1024 pixels). Black- and white-point reference was used for spatial and spectral normalization as well as correction for motion during exposure. Reflection spectra were extracted from the image on a line mid-buccal of the implant, starting 1mm above the soft tissue continuing up to 3mm apically. Results: Median soft tissue height is 2.3mm (min: 1.2mm and max: 3.1 mm). The buccal mucosa rapidly increases in the thickness, when moving apically. At 2.2mm, thickness is 3mm. No perceivable difference between the Ti and ZrO2 abutment can be observed when the thickness of the mucosa is 2 +/- 0.1mm (95% confidence interval) or more. Conclusion: It is expected that the difference in light reflection of soft tissue covering Ti or ZrO2 abutments is no longer noticeable for the human eye when the mucosa thickness exceeds 2mm. Haemoglobin peaks in the reflection spectrum can be observed and make hyper-spectral imaging a practical and useful tool for measuring soft tissue health

The use of near-infrared light for safe and effective visualization of subsurface blood vessels to facilitate blood withdrawal in children

<p>Obtaining access to blood vessels can be difficult, especially in children. Visualization of subsurface blood vessels might be a solution. Ultrasound and visible light have been used to this purpose, but have some drawbacks. Near-infrared light might be a better option since subsurface blood vessels can be visualized in high contrast due to less absorption and scattering in tissue as compared to visible light. Our findings with a multispectral imaging system support this theory.</p><p>A device, the VascuLuminator, was developed, based on transillumination of the puncture site with near-infrared light. The VascuLuminator was designed to meet the requirements of compact and safe use. A phantom study showed that the maximum depth of visibility (5.5 mm for a 3.6 mm blood vessel) is sufficient to visualize blood vessels in typical locations for peripheral venous and arterial access. A quantitative comparison of the VascuLuminator and to two other vessel imaging devices, using reflection of near-infrared light instead of transillumination, was conducted. The VascuLuminator is able to decrease failure at first attempt in blood withdrawal in pediatric patients from 10/80(13%) to 1/45 (2%; P = .05). (C) 2012 IPEM. Published by Elsevier Ltd. All rights reserved.</p>

Visualizing Veins With Near-Infrared Light to Facilitate Blood Withdrawal in Children

Introduction. This study aims to evaluate for the first time the value of visualizing veins by a prototype of a near-infrared (NIR) vascular imaging system for venipuncture in children. Methods. An observational feasibility study of venipunctures in children (0-6 years) attending the clinical laboratory of a pediatric university hospital during a period of 2 months without (n = 80) and subsequently during a period of 1 month with a prototype of an NIR vascular imaging system (n = 45) was conducted. Failure rate (ie, more than 1 puncture) and time of needle manipulation were determined. Results. With the NIR vascular imaging system, failure rate decreased from 10/80 to 1/45 (P =.05) and time decreased from 2 seconds (1-10) to 1 second (1-4, P =.07). Conclusion. This study showed promising results on the value of an NIR vascular imaging system in facilitating venipunctures

Crop domestication alters floral reward chemistry with potential consequences for pollinator Health

Crop domestication can lead to weakened expression of plant defences, with repercussions for herbivore and pathogen susceptibility. However, little is known about how domestication alters traits that mediate other important ecological interactions in crops, such as pollination. Secondary metabolites, which underpin many defence responses in plants, also occur widely in nectar and pollen and influence plant-pollinator interactions. Thus, domestication may also affect secondary compounds in floral rewards, with potential consequences for pollinators. To test this hypothesis, we chemically analysed nectar and pollen from wild and cultivated plants of highbush blueberry (Vaccinium corymbosum L.). Our results indicated that domestication has significantly altered the chemical composition of V. corymbosum nectar and pollen, and reduced pollen chemical diversity in cultivated plants. Of 20 plant metabolites identified in floral rewards, 13 differed significantly between wild and cultivated plants, with a majority showing positive associations with wild compared to cultivated plants. These included the amino acid phenylalanine (4.5 times higher in wild nectar, 11 times higher in wild pollen), a known bee phagostimulant and essential nutrient; and the antimicrobial caffeic acid ester 4-O-caffeoylshikimic acid (two times higher in wild nectar). We assessed the possible biological relevance of variation in caffeic acid esters in bioassays, using the commercially available 3-O-caffeoylquinic acid. This compound reduced Bombus impatiens infection by a prominent gut pathogen (Crithidia) atconcentrations that these esters occur in wild but not cultivated plants, suggesting that domestication may influence floral traits with consequences for bee health. Appreciable levels of genetic variation and heritability were found for most floral reward chemical traits, indicating good potential for selective breeding. Our study provides the first assessment of plant domestication effects on floral reward chemistry and its potential repercussions for pollinator health. Given the central importance of pollinators for agriculture, we discuss the need to extend such investigations to pollinator-dependant crops more generally and elaborate on future research directions to ascertain wider trends, consequences for pollinators, mechanisms, and breeding solutions