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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 40 (1993), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . Free-living soil amoebae consume a wide variety of food, including algae, yeast, small protozoa and especially bacteria, which they digest to fulfil their nutritional requirements. Amoebae play an active role in the nitrogen mineralization in soils due to their nitrogen metabolizing capacities. However, little is known about nitrogen metabolizing enzyme activities in these free-living soil amoebae. In this study a number of key enzymes involved in the nitrogen metabolism of the axeaically cultivated free-living soil amoebae Acanthamoeba castellanii, Acanthamoeba polyphaga and two different strains of Hartmannella vermiformis were determined. the specific enzyme activities for exponential growth phase ceils were calculated and it appeared that the species tested possessed urate oxidase, glutamine synthetase, NADH-dependent glutamate dehydrogenase, glutamate oxaloacetate transaminase and glutamate pyruvate transaminase activity. Glutamate synthase activity could not be detected in any of these species. the levels of specific activities varied depending on the enzymes tested. For all species the highest activities were detected for the transaminase reactions yielding glutamate, and for glutamate dehydrogenase. A general conclusion is that the pathway of nitrogen assimilation in free-living soil amoebae is similar to the one observed for other eukaryotes. Differences in specific activities were detected between the species.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Scandinavian journal of immunology 36 (1992), S. 0 
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Patients with gamma heavy chain disease (γ-HCD) generally produce incomplete immunoglobulin (Ig) γ-heavy chains (yγ-HCD protein) which cannot associate with light chains (IgL). In most patients Bence Jones proteins (BJP) are not observed. However, in the 61-year-old patienl WIN we found γl-HCD proteins and λ BJP in serum and urine. WIN -γl-HCD protein does not carry the Ig Fd region, has a molecular weight of 33.5 kDa, and the seven N-terminal amino acid residues are not translated from any of the known immunoglobulin heavy chain (IgH) gene sequences. These residues are followed by the Cγl-hinge region. In DNA from peripheral blood lymphocytes of patient WIN we found bands representing dominant rearrangements in one ofthe two alleles of the IgH, IgK and Igλ locus. Taken together, the data from protein and DNA analysis strongly suggest, albeit do not formally prove, that one dominant B-cell clone which carries it rearranged and a non-rearranged allele of each Ig locus produces γ-HCD protein and λ BJP. The productive λ-gene rearrangement in this clone thus has not been preceded by abortive rearrangements in both γ-locus alleles. Lymphocytes with an unusual sequence of IgL-chain gene activation seem to be involved in the case of γ-HCD described here.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Scandinavian journal of immunology 11 (1980), S. 0 
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Cultured cell lines derived from donors of various species as 75Se- or 51Cr-labelled targets in microcytotoxicity assays. As in human donors, considerable spontaneous cell-mediated cytotoxicity (SCMC) was exhibited by peripheral blood lymphoid effector cells from healthy chickens, mink, swine, cattle, horses and tigers. Although all target lines tested could be lysed in SCMC, there was no ‘general SCMC target’ for all species of all individuals of one species. The selectivity, the kinetics, and the strength of SCMC reflected the capacity of the effector cells rather than a ‘susceptibility’ of the target to lysis. Classical major histocompatibility complex products, determinants specific for distinct cell types or subpopulations, or antigens associated with Epstein-Barr virus, herpes virus ateles, herpes virus papio, or Marek's disease virus were not appreciably involved in SCMC. No ‘malignant phenotype’ on targets was required for the cytotoxic effect. Yet undefined xenogenic, allogenic, and individual structures seem to be involved in SCMC. Depending on their expression, a target can he classified as ‘species related’ or as ‘individual-related’. Intermediate forms are conceivable. SCMC might comprise different cytotoxic mechanisms. Antibodies are not required for lysis to occur, but serum factors including immunoglobulins can have considerable influence on SCMC.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Spontaneous (SCMC) and antibody dependent cellular cytotoxicity (ADCC); mitogenic responsiveness (PHA, Con A, PPD, dextran and pokeweed) as well as lymphocyte subpopulations (E-, EA-, EAC-rosettes, S-Ig) were studied simultaneously in peripheral blood (PBL) and synovial fluid lymphocytes (SFL) of fifteen patients with rheumatoid arthritis. Marked differences were observed in the cytotoxic activity of SFL and PBL. Whereas SCMC activity of SFL was always significantly elevated above the cytotoxic levels of PBL, the reverse was true for the ADCC reaction; here, 50% of the patients showed a decreased cytotoxicity of SFL compared to PBL. Synovial fluid neutrophils (SFN) were found to be inactive in both cytotoxic assays. No differences were found in ADCC activity of PBL between normal controls and RA patients. In SCMC assays a significantly increased activity of control PBL was only observed at L/T ratios of 100:1. Overnight incubation of PBL from RA patients and normal controls resulted in a marked decrease in SCMC and, to a smaller extent, in ADCC activity. SFL from three out of four patients lost less SCMC activity after overnight incubation than the corresponding PBL. In one patient even an increased activity in both cytotoxic systems was obtained. Regarding lymphocyte populations, T-cells were significantly decreased in PBL of RA patients. With the exception of a significantly lowered percentage of C3 receptor positive cells in SFL, no significant differences were recorded in the lymphocyte distribution between the patients' PBL and SFL. In the RA patients, the response to T-cell mitogens was significantly depressed in SFL while PPD and pokeweed reactivity was equal to that of PBL.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A soluble form of the complement receptor CD21 (sCD21) is shed from the lymphocyte surface. The amount of sCD21 in serum may modulate immunity as sCD21 levels are correlated with several clinical conditions. We report here the serum levels of sCD21 in juvenile arthritis (JA), systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS). Using enzyme-linked immunosorbent assay, we determined sCD21 levels in SLE, SS and JA patients. Mann–Whitney test for nonparametric two-tail P value was performed to obtain statistical significance. Cytometrical analysis of synovial fluid leucocytes of JA patients was done on a FACSsort. While sCD21 levels in SLE and SS are reduced to levels previously found in rheumatoid arthritis (RA), JA sCD21 levels were normal. sCD21 levels did not correlate with clinical parameters and immunophenotype of synovial cells. CD4 T cells in the synovium were almost all of the CD45RO memory type and 13 of 40 patients displayed synovial expansion of γδT cells. CD21 shedding in JA differs from RA/SS/SLE. JA sCD21 levels in synovial fluid are always lower compared to blood levels of the same patients. Analysis of JA synovial T cells indicates a T-cell driven response.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The functional T-cell repertoire in the inflamed joint of a patient with rheumatoid arthritis was analysed at the clonal level. Using limiting dilution techniques and selecting for growth of in vivo activated and/or autoreactive T cells, 149 T-cell lines were established. They were tested in a proliferation assay for reactivity against an autologous Epstein–Barr virus (EBV)-transformed B-cell line and a panel of auto-antigens and foreign antigens. Seventy-five lines (∼50%) could be stimulated. Thirty-six lines (∼24%) were antigen-reactive. They were stimulated by human collagens type I (15), II (10), IV (7) or V (4), cartilage proteoglycans (4), Mycobacterium tuberculosis (15), the 60 kDa heat-shock protein of M. bovis (13) or tetanus toxoid (10). T-cell lines were either monoreactive (19), bireactive (6), or multireactive (11), i.e. they were stimulated by either one, by two, or by more antigens in the panel. About half of the antigen-reactive lines were at the same time autoreactive towards the autologous B-cell line. These data suggest the existence of multispecific autoreactive T-cell receptors comparable to multireactive or natural autoantibodies and prove the presence of autoantigen-reactive T cells in the inflamed joints of patients with rheumatoid arthritis.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Using sera from patients with rheumatoid arthritis and antiglobulin preparations obtained from such sera, inhibition of human lymphocyte cytotoxicity in antibody-dependent (ADCC) and spontaneous cell-mediated cytotoxicity (SCMC) reactions against an allogeneic melanoma cell line (IGR3) has been demonstrated. Fractionation of effector cell preparations indicated that Fc-receptor-bearing lymphocytes were operative in both reactions. Removal of phagocytic and adherent cells from the effector cell population resulted in more pronounced inhibition of SCMC and ADCC reactions by rheumatoid sera. The results indicate that anti-globulin preparations from human sera containing rheumatoid factor activity can effectively block the cytotoxic activity of Fc-receptor-bearing effector lymphocytes (K cells) in vitro. On analogy with the inhibition of ADCC and SCMC reactions by immune complexes and aggregated IgG, antiglobulin complexes present in the antiglobulin preparations are responsible for this effect.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 612 (1990), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1546-1718
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] The functional interaction of BAFF and APRIL with TNF receptor superfamily members BAFFR, TACI and BCMA is crucial for development and maintenance of humoral immunity in mice and humans. Using a candidate gene approach, we identified homozygous and heterozygous mutations in TNFRSF13B, encoding ...
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 44 (1997), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . The small subunit ribosomal DNA sequence (SSU rDNA) of the microaerophilic free-living amoeboflagellate Psalteriomonas lanterna has been sequenced and analyzed. The gene is 1,945 bp long and has a G + C content of 33.4%. Based upon ultrastructural studies, P. lanterna has been placed in the class Lyromonadea within the phylum Percolozoa Cavalier-Smith, 1991. However, based upon cytological characteristics, this microaerophilic free-living amoeboflagellate appears to be very primitive. It shares certain characteristics in common with some archezoans, i.e. it lacks mitochondria and dictyosomes but contains hydrogenosomes. Despite sharing these characteristics with the amitochondriate taxa, P. lanterna is not related to any of these taxa but instead to the Vahlkampfiidae. Therefore, we used primary sequence data and the secondary structure of the SSU rDNA gene to determine the placement P. lanterna in the phylogenetic tree. Our analyses showed that P. lanterna groups as a sister taxon to the Vahlkampfiidae but probably diverged from them quite early.
    Type of Medium: Electronic Resource
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