39 research outputs found

    Assessment of factors associated with complete immunization coverage in children aged 12-23 months: a cross-sectional study in Nouna district, Burkina Faso

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    This study identifies specific factors associated with immunization status in Nouna health district (Burkina Faso) in order to advance improved intervention strategies in this district and in those with similar environmental and social contexts. While comprehensive communication may improve understanding about immunization, local interventions should also take into account religious specificities and critical economic periods. Communication problems need to be examined; for instance, many respondents did not understand what the health workers wanted; and or they assumed their child was already totally immunized. Particular approaches that take into consideration local distinctions need to be applied

    Completely enzymic synthesis of the mucin-type sialyl Lewis x epitope, involved in the interaction between PSGL-1 and P-selectin

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    Sialyl Lewis x (sLex) is an established selectin ligand occurring on N- and O-linked glycans. Using a completely enzymic approach starting from p-nitrophenyl N-acetyl-alpha-D-galactosaminide (GalNAc(alpha1-pNp as core substrate, the sLex-oligosaccharide Neu5Ac(alpha2-3)Gal(beta1-4)[Fuc(alpha1-3)]GlcNAc(beta1-6)[Gal(beta1-3)]GalNAc(alpha1-pNp, representing the O-linked form, was synthesized in an overall yield of 32%. In a first step, Gal(beta1-3)GalNAc(alpha1-pNp was prepared in a yield of 52% using UDP-Gal and an enriched preparation of beta3-galactosyltransferase (EC 2.4.1.122) from rat liver. UDP-GlcNAc and a recombinant affinity-purified preparation of core 2 beta6-N-acetylglucosaminyltransferase (EC 2.4.1.102) fused to Protein A were used to branch the core 1 structure, affording GlcNAc(beta1-6)[Gal(beta1-3)]GalNAc(alpha1-pNp in a yield of >85%. The core 2 structure was galactosylated using UDP-Gal and purified human milk beta4-galactosyltransferase 1 (EC 2.4.1.38) (yield of >85%), then sialylated using CMP-Neu5Ac and purified recombinant alpha3-sialyltransferase 3 (EC 2.4.99.X) (yield of 87%), and finally fucosylated using GDP-Fuc and recombinant human alpha3-fucosyltransferase 6 (EC 2.4.1.152) produced in Pichia pastoris (yield of 100%). Overall 1.5 ”mol of product was prepared. MALDI TOF mass spectra, and 1D and 2D TOCSY and ROESY 1H NMR analysis confirmed the obtained structure

    UDP-N-acetyl-α-D-glucosamine as acceptor substrate of ÎČ-1,4-galactosyltransferase : Enzymatic synthesis of UDP-N-acetyllactosamine

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    The capacity of UDP-N-acetyl-α-D-glucosamine (UDP-GlcNAc) as an in vitro acceptor substrate for ÎČ-1,4-galactosyltransferase (ÎČ4GalT1, EC 2.4.1.38) from human and bovine milk and for recombinant human ÎČ4GalT1, expressed in Saccharomyces cerevisiae, was evaluated. It turned out that each of the enzymes is capable to transfer Gal from UDP-α-D-galactose (UDP-Gal) to UDP-GlcNAc, affording Gal(ÎČ1-4)GlcNAc(α1-UDP (UDP-LacNAc). Using ÎČ4GalT1 from human milk, a preparative enzymatic synthesis of UDP-LacNAc was carried out, and the product was characterized by fast-atom bombardment mass spectrometry and 1H and 13C NMR spectroscopy. Studies with all three ÎČ4GalTs in the presence of α-lactalbumin showed that the UDP-LacNAc synthesis is inhibited and that UDP-α-D-glucose is not an acceptor substrate. This is the first reported synthesis of a nucleotide-activated disaccharide, employing a Leloir glycosyltransferase with a nucleotide-activated monosaccharide as acceptor substrate. Interestingly, in these studies ÎČ4GalT1 accepts an α-glycosidated GlcNAc derivative. The results imply that α4GalT1 may be responsible for the biosynthesis of UDP-LacNAc, previously isolated from human milk

    UDP-N-acetyl-α-D-glucosamine as acceptor substrate of ÎČ-1,4-galactosyltransferase : Enzymatic synthesis of UDP-N-acetyllactosamine

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    The capacity of UDP-N-acetyl-α-D-glucosamine (UDP-GlcNAc) as an in vitro acceptor substrate for ÎČ-1,4-galactosyltransferase (ÎČ4GalT1, EC 2.4.1.38) from human and bovine milk and for recombinant human ÎČ4GalT1, expressed in Saccharomyces cerevisiae, was evaluated. It turned out that each of the enzymes is capable to transfer Gal from UDP-α-D-galactose (UDP-Gal) to UDP-GlcNAc, affording Gal(ÎČ1-4)GlcNAc(α1-UDP (UDP-LacNAc). Using ÎČ4GalT1 from human milk, a preparative enzymatic synthesis of UDP-LacNAc was carried out, and the product was characterized by fast-atom bombardment mass spectrometry and 1H and 13C NMR spectroscopy. Studies with all three ÎČ4GalTs in the presence of α-lactalbumin showed that the UDP-LacNAc synthesis is inhibited and that UDP-α-D-glucose is not an acceptor substrate. This is the first reported synthesis of a nucleotide-activated disaccharide, employing a Leloir glycosyltransferase with a nucleotide-activated monosaccharide as acceptor substrate. Interestingly, in these studies ÎČ4GalT1 accepts an α-glycosidated GlcNAc derivative. The results imply that α4GalT1 may be responsible for the biosynthesis of UDP-LacNAc, previously isolated from human milk

    Reconsidering the water system of Roman Barcino (Barcelona) from supply to discharge

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    This paper presents the results of the ‘Roman Barcino Water Network’ Project. This study employed a series of methodologies aiming at joining and interpreting all data available on water supply, distribution, management, use and discharge in the Romancolony of Barcino (modern Barcelona). Analyses of the results substantially modified previous knowledge of Barcino’s water organization and provided one of the few examples in which the whole water system of a Roman city has been tackled. We concluded that the water supply employed a single aqueduct, which divided before entering the city and not two of them as it was previously assumed. Barcino’s water distribution system was designed according to the different uses of water and was conditioned by the city’s particular topography. The results also stress the colony’s ample water availability, which despite its small size, allowed the maintenance of multiple public and private baths as befitted an accommodated population of merchants and administrators

    Expression of recombinant proteins in a lipid A mutant of Escherichia coli BL21 with a strongly reduced capacity to induce dendritic cell activation and maturation

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    Mutations in the Escherichia coli (E. coli) and Salmonella lpxM gene have been shown to result in strains which grow normally and which produce a non-myristoylated lipopolysaccharide (nmLPS) with strongly reduced endotoxicity. Using homologous recombination, we inactivated the lpxM gene in BL21 (DE3), a strain widely used for the production of recombinant proteins. This led to a derivative unaffected in its capacity to support the production of recombinant proteins. This new strain expresses non-myristoylated LPS that induces markedly less activation and maturation of monocyte-derived dendritic cells (DC), as assessed by nuclear translocation of nuclear factor kappa B (NF-kappaB), production of TNF-alpha and IL-8 or expression of CD86. Activation of the main signal transducing receptor for extracellular LPS, Toll like receptor (TLR) 4 in conjunction with the soluble accessory protein MD-2 was also markedly decreased.The modified BL21 strain represents a new application of lpxM inactivation for the expression of proteins to be tested on dendritic cells or other LPS sensitive cells/receptor complexes. It is likely to be useful for the identification of new proteins activating the innate immune response and to reducing the risk linked with low level of endotoxin contamination in therapeutic recombinant proteins
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