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  • 1
    Digitale Medien
    Digitale Medien
    Clustering of C-Type Lectin Natural Killer Receptor-Like Loci in the Bony Fish Oreochromis niloticus (2004)
    Oxford, UK; Malden , USA : Blackwell Science Ltd
    Scandinavian journal of immunology 59 (2004), S. 0 
    Details
    ISSN: 1365-3083
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The genome of the cichlid (teleost) fish Oreochromis niloticus contains a set of genes which encode group V C-type lectin proteins homologous to the mammalian NKG2/CD94 family of natural killer (NK) cell receptors. To determine the genomic organization of these killer cell-like receptor (KLR) genes, an O. niloticus BAC library was screened with a cDNA probe derived previously from an expressed sequence tag of the related cichlid species Paralabidochromis chilotes. Four distinct KLR-bearing BAC clones were analysed, three of which could be assembled into a contig. One of the clones was sequenced in its entirety, whereas the others were partially sequenced to identify the KLR loci borne by them. Altogether, 28 distinct KLR loci were identified, of which at least 26 occupy a single chromosomal region, the KLR complex. One half of the loci appear to be occupied by pseudogenes. Compared to the human NK cell receptor complex, the Oreochromis KLR complex is more compact and, apart from transposons, appears to contain only KLR loci. The gene density of the complex is one KLR locus per 18 kb of sequence. All the KLR loci constituting the complex are derived from a single most recent common ancestor, which is estimated to have existed 7.7 million years ago. The 180 kb of the determined sequence is a mosaic of blocks of similar segments reflecting a complex history of duplications, deletions and rearrangements. The transposons found in the sequenced part belong to the TC1, Xena, CR1 and TX1 families.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.0300-9475.2004.01372.x
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  • 2
    Digitale Medien
    Digitale Medien
    Linkage Relationships of Genes Coding for α2-Macroglobulin, C3 and C4 in the Zebrafish: Implications for the Evolution of the Complement and Mhc Systems (2002)
    Oxford, UK : Blackwell Science Ltd
    Scandinavian journal of immunology 56 (2002), S. 0 
    Details
    ISSN: 1365-3083
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The α2-macroglobulin (A2M) and the complement components C3 and C4 are related proteins derived from a common ancestor. Theoretically, this derivation could have occurred either by tandem duplications of their encoding genes or by polyploidization involving chromosomal segments, a chromosome or the whole genome. In tetrapods the A2M-, C3- and C4-encoding genes are generally each located on a different chromosome. This observation has been interpreted as supporting their origin by polyploidization. We identified and mapped (with the help of a radiation hybrid panel of cell lines) the A2M, C3 and C4 loci in the zebrafish, Danio rerio. Each of the three types of loci is present in the zebrafish in multiple copies, but all of the identified copies of a given type map to the same region in linkage groups 1 (C3) and 15 (A2M, C4). The A2M and C4 loci are mapped in the same region not linked to any of the class I or class II major histocompatibility complex (Mhc) loci. These observations are interpreted as supporting the origin of the A2M family of genes by tandem duplications, followed by the dispersal of the copies to different chromosomes. It is also argued that the association of C4 with the class I/II loci in tetrapods is accidental and without functional significance.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1365-3083.2002.01154.x
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  • 3
    Digitale Medien
    Digitale Medien
    Phylogeny of Antigen-Processing Enzymes: Cathepsins of a Cephalochordate, an Agnathan and a Bony Fish (2003)
    Oxford, UK : Blackwell Science Ltd
    Scandinavian journal of immunology 58 (2003), S. 0 
    Details
    ISSN: 1365-3083
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Cathepsins are enzymes that have been cleaving peptide bonds of lysosomal proteins probably since lysosomes appeared in early eucaryotes. When the adaptive system emerged in gnathostomes, cathepsins were recruited to produce peptides for loading onto the major histocompatibility complex class II molecules and for degrading the class II-associated invariant chain just before the loading. The circumstances under which this recruitment took place are unclear because the knowledge about vertebrate cathepsins is limited largely to mammals. To shed light on the recruitment, 10 amphioxus, one lamprey and one cichlid fish cathepsin cDNA clone were characterized and analysed phylogenetically. Disregarding cathepsin O, whose phylogenetic position is uncertain, the analysis confirms the existence of two old lines of descent, the B and the L lineages of cathepsins, which diverged from each other early in the evolution of eucaryotes. The B lineage encompasses cathepsins B, C and Z (X). The L lineage splits off sublineages encompassing cathepsins F and W before the plant–animal separation and cathepsin H early in the evolution of the metazoa. The remaining cathepsins belonging to the L lineage diverged from one another during the evolution of vertebrates: S, K and L before the emergence of bony fishes, and the group of rodent placentally expressed cathepsins [J (P), M, Q, R, 3, 6, 7 and 8] as well as the testis/ova-expressed cathepsins (testins) probably after the divergence of rodents from primates. The part possibly played by the adaptive immune system in some of these divergences is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1365-3083.2003.01322.x
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  • 4
    Digitale Medien
    Digitale Medien
    Providing assisted reproductive care to male haemophiliacs infected with human immunodeficiency virus: preliminary experience (2003)
    Oxford, UK : Blackwell Science Ltd
    Haemophilia 9 (2003), S. 0 
    Details
    ISSN: 1365-2516
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Summary.  Outlined is our experience with couples in whom the male was both human immunodeficiency virus (HIV) seropositive and a haemophiliac who underwent assisted reproductive technologies (ART) in order to attain family goals while minimizing the risk of HIV transmission. We report their demographics, attitudes towards assisted reproduction, and ART performance and outcomes. The study included HIV serodiscordant couples (n = 11) who underwent ART at a university-based infertility practice from August 1997 to May 2002. Prior to treatment, couples prospectively completed a survey regarding their demographics and attitudes towards assisted reproduction. All couples underwent ART and pregnancy outcomes were analysed. The majority of the patients were fully employed, college-educated, in good health, married and motivated to have a child while minimizing the risk of HIV transmission. Eleven couples underwent 25 cycles of ART [19 in vitro fertilization (IVF) cycles; five frozen embryo transfer cycles; and one oocyte donation cycle] resulting in nine successful pregnancies. The ongoing/delivered pregnancy rate per initiated IVF cycle was 42.1% per embryo transfer. Eight of 11 (72.7%) couples achieved a successful pregnancy. More than half (six of 11; 54.5%) the couples conceived during their initial attempt. Four of nine (44.4%) pregnancies were multiple gestations, including three sets of triplets. All female recipients tested seronegative for HIV at 3 and 6 months post-embryo transfer. All delivered babies (n = 8) tested seronegative for HIV at birth and 3 months postpartum. Four pregnancies are currently ongoing. ART should be considered for HIV serodiscordant couples with haemophilia who desire to have children in order to minimize the risk of viral infection.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1365-2516.2003.00748.x
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  • 5
    Digitale Medien
    Digitale Medien
    Effect of the Penetration of X-Rays on the Resolving Power (1937)
    [s.l.] : Nature Publishing Group
    Nature 139 (1937), S. 886-887 
    Details
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] FROM the generality of the principle of uncertainty ΔE.Δt = h, it follows that the equation for the resolving power of a grating λ/dλ = m.n (where λ is wave-length, m is number of rulings, n is order of the spectrum) is valid not only for the ruled grating, but also for space-lattices. On the ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/139886b0
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  • 6
    Digitale Medien
    Digitale Medien
    Awake craniotomy for glioblastoma in a 9-year-old child (2004)
    Oxford, UK : Blackwell Science Ltd
    Anaesthesia 59 (2004), S. 0 
    Details
    ISSN: 1365-2044
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: We report the pre-operative preparation and anaesthetic management for resection of an intracerebral tumour during awake craniotomy in a 9-year-old boy. We believe this is the youngest patient reported to have undergone this procedure. The challenges of sedation and psychological care throughout the procedure are discussed. We conclude that the procedure can be performed safely and that it seems unacceptable to uphold an age restriction. We believe that it is the individual level of development of the child that determines suitability for this type of surgery.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1365-2044.2004.03675.x
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  • 7
    Digitale Medien
    Digitale Medien
    The HIV-1 protease inhibitor indinavir impairs insulin signalling in HepG2 hepatoma cells (2000)
    Springer
    Diabetologia 43 (2000), S. 1145-1148 
    Details
    ISSN: 1432-0428
    Schlagwort(e): Keywords HIV protease inhibitors ; lipodystrophy syndrome ; diabetes mellitus ; insulin resistance ; insulin signalling.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Aims/hypothesis. Patients treated with human immunodeficiency virus-1 protease inhibitors often develop impaired glucose tolerance or diabetes, most likely due to an induction of insulin resistance. We therefore investigated whether the protease inhibitor indinavir alters insulin signalling. Methods. We incubated HepG2 cells for 48 h without or with indinavir (100 μmol/l). Subsequently 125I-insulin binding to the cells and the effects of insulin stimulation on insulin-receptor substrate-1-phosphorylation, association of phosphatidylinositol 3-kinase with insulin-receptor substrate-1 and Akt-Thr308-phosphorylation were measured. Results. In cells not exposed to indinavir, insulin (100 nmol/l) led to rapid increases of insulin-receptor substrate-1-phosphorylation, association of phosphatidylinositol 3-kinase with insulin-receptor substrate-1 and Akt-phosphorylation during the first 75 s, followed by subsequent decreases. In indinavir-treated cells, these insulin-stimulated increases during the first 75 s were reduced by 30–60 % and this was not associated with alterations in cell number or viability, insulin binding to the cells or cellular insulin-receptor substrate-1-content. Conclusion/interpretation. Effects of indinavir on initial insulin signalling could cause, or contribute to, the metabolic effects of human immunodeficiency virus-1 protease inhibitors. [Diabetologia (2000) 43: 1145–1148]
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s001250051505
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  • 8
    Digitale Medien
    Digitale Medien
    Major histocompatibility complex class II A genes in cichlid fishes: identification, expression, linkage relationships, and haplotype variation (2000)
    Springer
    Immunogenetics 51 (2000), S. 576-586 
    Details
    ISSN: 1432-1211
    Schlagwort(e): Key words Mhc ; Oreochromis ; Tilapia ; Haplochromis ; Cichlidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  Two cichlid species, the haplochromine Aulonocara hansbaenschi and the tilapiine Oreochromis niloticus, were used to study the major histocompatibility complex (Mhc) class II A variation within this group. Multiple class II A sequences were recovered from A. hansbaenschi and O. niloticus cDNA libraries and three sequence families, DAA, DBA, and DCA, were identified. Sets of O. niloticus haploid embryo families were used to determine the linkage relationships of these genes. Two independently assorting linkage groups were detected, DAA and DBA/DCA, neither of which is linked to the previously described Mhc class I gene cluster. Three DCA genes and up to four DBA genes were found to segregate in different haplotypes, whereas DAA occurred as a single locus. Four DBA haplotypes, DBA*H1-H4, were identified and shown to co-segregate with the previously described class II B haplotypes. Four DCA haplotypes, DCA*H1-H4, were found at a distance of 37 cM from the DBA/class II B cluster; in one DCA haplotype, DCA*H5, the genes were tightly linked to the DBA/class II B clusters. Transcripts of DAA and DBA genes were found in O. niloticus hepatopancreas and spleen; transcripts of DCA genes were detected in the A. hansbaenschi cDNA library, but not in O. niloticus. These findings provide a basis for using class II haplotypes as markers in the study of adaptive radiation in the cichlid species flocks of the East African Great Lakes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002510000177
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  • 9
    Digitale Medien
    Digitale Medien
    Nonlinkage of major histocompatibility complex class I and class II loci in bony fishes (2000)
    Springer
    Immunogenetics 51 (2000), S. 108-116 
    Details
    ISSN: 1432-1211
    Schlagwort(e): Key words Gasterosteus aculeatus ; Poecilia reticulata ; Oreochromis niloticus ; Gene families ; Mhc organization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract  In tetrapods, the functional (classical) class I and class II B loci of the major histocompatibility complex (Mhc) are tightly linked in a single chromosomal region. In an earlier study, we demonstrated that in the zebrafish, Danio rerio, order Cypriniformes, the two classes are present on different chromosomes. Here, we show that the situation is similar in the stickleback, Gasterosteus aculeatus, order Gasterosteiformes, the common guppy, Poecilia reticulata, order Cyprinodontiformes, and the cichlid fish Oreochromis niloticus, order Perciformes. These data, together with unpublished results from other laboratories suggest that in all Euteleostei, the classical class I and class II B loci are in separate linkage groups, and that in at least some of these taxa, the class II loci are in two different groups. Since Euteleostei are at least as numerous as tetrapods, in approximately one-half of jawed vertebrates, the class I and class II regions are not linked.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002510050019
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  • 10
    Digitale Medien
    Digitale Medien
    Convergent evolution of major histocompatibility complex molecules in humans and New World monkeys (2000)
    Springer
    Immunogenetics 51 (2000), S. 169-178 
    Details
    ISSN: 1432-1211
    Schlagwort(e): Key words Molecular convergence ; New World monkeys ; HLA-DRB ; Major histocompatibility complex evolution ; Gene conversion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract   In both Old World and New World monkeys Mhc-DRB sequences have been found which resemble human DRB1*03 and DRB3 genes in their second exon. The resemblance is shared sequence motifs and clustering of the genes or the encoded proteins in phylogenetic trees. This similarity could be due to common ancestry, convergence at the molecular level, or chance. To test which of these three explanations applies, we sequenced segments of New World monkey and macaque genes which encompass the entire second exon and large parts of both flanking introns. The test strongly supports the monophyly of New World monkey DRB intron sequences. The phylogenies of introns 1 and 2 from DRB1*03-like and DRB3-like genes are congruent, but both are incongruent with the exon 2-based phylogeny. The matching of intron 1- and intron 2-based phylogenies with each other suggests that reciprocal recombination has not played a major role in exon 2 evolution. Statistical comparisons of exon 2 from different DRB1*03 and DRB3 lineages indicate that it was neither gene conversion (descent), nor chance, but molecular convergence that has shaped their characteristic motifs. The demonstration of convergence in anthropoid Mhc-DRB genes has implications for the classification, age, and mechanism of generation of DRB allelic lineages.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002510050028
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