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V Snieckus [Queen's University, Canada]—The Directed Ortho Metalation—Cross Coupling Symbiosis in Aromatic Synthesis.N Geach, GP Randall, CJ Winfield [Scynexis, UK]—Isotopically Labelled 4‐Formylimidazole.A Studer [Marburg University, Germany]—New Concepts in Tin‐Free Radical Chemistry.AC Spivey, C Noban [Imperial College London, UK]. T Jones [Sheffield University, UK], GJ Ellames, A Kohler [Sanofi‐Synthélabo, UK], H Wadsworth [Amersham Biosciences, UK]—Opportunities for Isotope Labelling via Solid Phase Synthesis with Organogermanium Linkers.J Rieke‐Zapp [Aventis Pharma, Germany]—Optimization of Reaction Conditions on mg‐Scale by Use of Screening Devices.S Stone‐Elander [Karolinska Institute, Sweden]—Rerouting Radiochemistry with Microwaves.J Goehl, B Perry, D Leuck, J Windels, M Marx [EaglePicher Pharmaceutical, USA]—GMP and Radiolabelled Syntheses of Capsaicin.J Krüger, B Manmontri, G Fels [Paderborn University, Germany]—H/D‐Exchange in Aromatic Systems Using Transition Metal Catalysis.F Wüst, T Kniess, R Bergmann [Research Centre Rossendorf, Germany]—Synthesis of a11C‐Labelled Nonsteroidal Glucocorticoid Receptor Ligand as Potential Radiotracer for Imaging Brain Glucocorticoid Receptors with Positron Emission Tomography (PET).P Mäding, F Füchtner [Research Centre Rossendorf, Germany], CS Hilger [Schering AG, Germany]. M Halks‐Miller, R Horuk [Berlix Biosciences, USA]—18F‐Labelling of a Potent Nonpeptide CCR1 Antagonist for the Diagnosis of the Alzheimer's Disease.L Matei, C Postolache, V Fugaru, E Condac, A Dinischiotu, M Costache [Bukarest University, Romania]—Use of [1,2‐3H] Testosterone in 5α‐ Reductase Enzymatic Activity Dosing in Dermal Fibroblast Cultures from Polycystic Ovarian Patients.L Matei, C Postolache, V Fugaru [Bukarest University, Romania]—Synthesis and Stability Studies of Acyclovir Labelled with Tritium.J Atzrodt, V Derdau [Aventis Pharma, Germany]—Studies on Directed Ortho‐Metalation (DoM) as Convenient Tool for the Synthesis of Labeled Compounds.

Stem explants and leaves (without petioles) excised from axenic shoots of Populus tremula cv. Ahle or P. tremula × tremuloides cv. Münden were cultured in the presence of the non-ionic, co-polymer surfactant, Pluronic F-68. Stem explants developed shoots within 10 d of culture and significant (p<0.05), but genotype-dependent, increases in total shoot fresh weight (maximum 2 × control) occurred in cultures supplemented with 0.001–0.1% Pluronic F-68 over a 72 d period. Similarly, increases in both fresh weight (up to 10-fold) and number of shoots per P. tremula × tremuloides leaf explant (5-fold maximum) over 60 d occurred with Pluronic F-68 at 0.001%.

Cloning and expression of chimpanzee FUT3, FUT5, and FUT6 genes confirmed the hypothesis that the gene duplications at the origin of the present human cluster of genes occurred between: (i) the great mammalian radiation 80 million years ago and (ii) the separation of man and chimpanzee 10 million years ago. The phylogeny of fucosyltransferase genes was completed by the addition of the FUT8 family of alpha(1,6)fucosyltransferase genes, which are the oldest genes of the fucosyltransferase family. By analysis of data banks, a new FUT8 alternative splice expressed in human retina was identified, which allowed mapping the human FUT8 gene to 14q23. The results suggest that the fucosyltransferase genes have evolved by successive duplications, followed by translocations, and divergent evolution from a single ancestral gene.

Only one bovine gene, corresponding to the human cluster of genes FUT3-FUT5-FUT6, was found by Southern blot analysis. The cognate bovine alpha(1,3)-fucosyltransferase shares 67.3, 69.0, and 69.3% amino acid sequence identities with human FUC-T3, FUC-T5, and FUC-T6 enzymes, respectively. As revealed by protein sequence alignment, potential sites for asparagine-linked glycosylation and conserved cysteines, the bovine enzyme is an intermediate between FUC-T3, FUC-T5, and FUC-T6 human enzymes. Transfected into COS-7 cells, the bovine gene induced the synthesis of an alpha(1, 3)-fucosyltransferase enzyme with type 2 substrate acceptor pattern specificity and induced expression of fucosylated type 2 epitopes (Lex and sialyl-Lex), but not of type 1 structures (Lea or sialyl-Lea), suggesting that it has an acceptor specificity similar to the human plasma FUC-T6. However, no enzyme activity was detected in bovine plasma. Gene transcripts are detected on tissues such as bovine liver, kidney, lung, and brain. The type 2 sialyl-Lex epitope was found in renal macula densa and biliary ducts, and Lex and Ley epitopes were detected on the brush border of epithelial cells of small and large intestine, suggesting a tissue distribution closer to human FUC-T3, but fucosylated type 1 structures (Lea, Leb, or sialyl-Lea) were not detected at all in any bovine tissue. Analysis of genetic distances on a combined phylogenetic tree of fucosyltransferase genes suggests that the bovine gene is the orthologous homologue of the ancestor of human genes constituting the present FUT3-FUT5-FUT6 cluster.

The Lewis alpha(1,3/1,4)-fucosyltransferase, Fuc-TIII, encoded by the FUT3 gene is responsible for the final synthesis of Lea and Leb antigens. Various point mutations have been described explaining the Lewis negative phenotype, Le(a-b-), on erythrocytes and secretions. Two of these, T202C and C314T originally described in a Swedish population, have not been found as single isolated point mutations so far. To define the relative contribution of each of these two mutations to the Lewis negative phenotype, we cloned and made chimeric FUT3 constructs separating the T202C mutation responsible for the amino acid change Trp68 --> Arg, from the C314T mutation leading to the Thr105 --> Met shift. COS-7 cells were transfected and the expression of Fuc-TIII enzyme activity and the presence of Lewis antigens were determined. There was no decrease in enzyme activity nor of immunofluorescence staining on cells transfected with the construct containing the isolated C314T mutation compared with cells transfected with a wild type FUT3 allele control. No enzyme activity nor immunoreactivity for Lewis antigens was detected in FUT3 constructs containing both mutations in combination. The T202C mutation alone decreased the enzyme activity to less than 1% of the activity of the wild type FUT3 allele. These results demonstrate, that the Trp68 --> Arg substitution in human Fuc-TIII is the capital amino acid change responsible for the appearance of the Le(a-b-) phenotype on human erythrocytes in individuals homozygous for both the T202C and C314T mutations.

AbstractObjective: Definition of the molecular basis of the Reunion and the Bombay red cell and salivary H-deficient phenotypes. Methods: Sequence and expression of FUT1 and FUT2 genes from H-deficient individuals. Family segregation analysis of the mutations responsible for the fucosyltransferase defects of H, secretor and Lewis systems. Results: The Indian red cell H null Bombay phenotype depends on a new mutation of the FUT1 gene. T725 → G changing Leu242 → Arg. Their salivary nonsecretor phenotype is secondary to a complete deletion of the FUT2 gene. The red cell H weak Reunion phenotype depends on another new mutation of FUT1, C349 → T which induces a change of His117 → Tyr. Their salivary nonsecretor phenotype is due to the known Caucasian inactivating mutation G428 → A. Conclusion: Single prevalent FUT1 and FUT2 point mutations and a deletion are responsible for the Indian Bombay H null and the Reunion H weak phenotypes found on Reunion island. This is in contrast with other H-deficient phenotypes where sporadic nonprevalent inactivating mutations are the rule.

For detection of small pancreatic tumors and characterization of focal pancreatic masses, endoscopic ultrasound (EUS) is the most sensitive of the imaging procedures currently available. Differential diagnosis between benign and malignant focal pancreatic masses based on the EUS appearance is difficult and frequently requires EUS-guided fine needle aspiration (EUS-FNA) for confirmation of malignancy. New techniques improve the sensitivity, specificity, and accuracy of the differential diagnosis, as well as diagnosis of small pancreatic tumors (less than 2 cm diameter) by using real-time elastography or contrast-enhanced EUS. Nevertheless, EUS-FNA is still required for the final diagnosis in most of the cases, which allows an evidence-based management with referral to either curative surgery or palliative chemoradiotherapy. This article is part of an expert video encyclopedia.