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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, U.K. and Cambridge, USA : Blackwell Science Ltd
    Scandinavian journal of immunology 44 (1996), S. 0 
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The human leukaemia cell line KU812 has previously been used to study basophil differentiation. In this study the authors analysed the capacity of KU812 to produce the mast cell proteinase tryptase and to synthesize factor(s) mitogenic for fibroblasts. KU812 cells were treated with tetradecanoyl-phorbol-13-acetate (TPA), conditioned medium from the human T-cell line Mo (Mo-CM), or cultured under serum free conditions. After 4 days the cells were analysed for cell growth, differentiation, content of tryptase, and secretion of fibroblast mitogenic activity. Mo-CM and serum starvation increased the expression while TPA treatment down-regulated the expression of FcεRI-α chain. An increase in tryptase content in cell extracts was detected after 4 days of culture in serum-free medium or in the presence of Mo-CM. KU812 conditioned media was found to have a baseline expression of mitogenic activity on normal human foreskin fibroblasts that was increased after serum starvation or after treatment with TPA. Mast cell-derived tryptase has previously been reported to be mitogenic for fibroblasts, but in this study the expression of tryptase did not correlate with the expression of fibroblast mitogenic activity in KU812 cells. Furthermore, affinity-purified lung tryptase did not show any mitogenic activity. Platelet-derived growth factor was also excluded. Although the factor(s) from KU812 cells stimulating fibroblast proliferation have not been identified, our results indicate that basophils may be potential producers of growth factors inducing fibroblast proliferation.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Symptoms of allergic rhinitis are accompanied by infiltration of the nasal mucosa with inflammatory cells, predominantly eosinophils and metachromatic cells (basophils and mast cells). Specific immunotherapy (IT) reduces mucosal eosinophilia and numbers of metachromatic cells in the epithelium. A specific marker distinguishing basophils from mast cells was recently developed.Objectives The basophil-specific monoclonal antibody 2D7 was used to determine the influence of subcutaneous IT on numbers of nasal mucosal basophils compared with the effects of IT on neutrophils, eosinophils and mast cells.Method During a randomized, placebo-controlled trial of grass pollen IT in 44 adults with severe summer hay fever, nasal biopsies were taken at baseline, out of the pollen season, and at the peak of the pollen season following 2 years treatment. Biopsies were processed for immunohistochemistry for basophils (2D7+), mast cells (AA1+), eosinophils (MBP+) and neutrophils (neutrophil elastase+).Results In placebo-treated (PL) patients there were significant seasonal increases in basophils (P 〈 0.01), mast cells (P 〈 0.05) and eosinophils (P = 0.002) in the nasal submucosa. In IT-treated patients significant increases in 2D7+ cells (P 〈 0.01) and eosinophils (P = 0.01) but not AA1+ cells (P = 0.9) were observed. These differences were significant between groups for eosinophils (P 〈 0.05). In the epithelium there were seasonal increases in AA1+ cells and eosinophils in both groups (PL: P 〈 0.01, IT: P 〈 0.05 for both). The between-group difference was significant for eosinophils (P = 0.05). Basophils were observed in the epithelium of six out of 17 in the placebo group and one out of 20 in the IT group (P = 0.03). Neutrophil numbers remained constant in both epithelium and submucosa.Conclusion Successful grass pollen immunotherapy was associated with inhibition of seasonal increases in basophils and eosinophils, but not mast cells or neutrophils within the nasal epithelium. Immunotherapy may act, at least in part, by reducing seasonal recruitment of basophils and eosinophils into the epithelium.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science, Ltd
    Clinical & experimental allergy 31 (2001), S. 0 
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Clinical & experimental allergy 25 (1995), S. 0 
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background: Serum tryptase levels reflect mast cell activation and correlate with anaphylactic reactions. Elevated post-mortem serum tryptase levels have been found in witnessed fatal anaphylaxis.Objective: This study was designed to examine whether or not unwitnessed anaphylaxis may be a hitherto unrecognized cause of sudden unexplained death.Methods: Mast cell tryptase was measured by immunoassay in 68 post-mortem sera remaining from a previous study which reported elevated venom-specific IgE antibodies in 22 (23%) of 94 victims of sudden unexpected death. Autopsies were performed in all cases. The cause of death was independently reported by pathologists unfamiliar with the nature of this study.Results: Serum tryptase levels were elevated (〉 10ng/mL) in nine of 68 cases. The levels could not be predicted from the clinical circumstances surrounding death. Sera from four individuals contained both elevated tryptase and previously reported elevated venom-specific IgE.Conlusions: We conclude that mast cell activation may accompany up to 13% of sudden unexpected deaths in adults. Measurement of both tryptase and specific IgE antibody levels in post-mortem sera from persons experiencing sudden, unexpected death may identify a small subset of cases due to clinically unrecognized fatal anaphylaxis, including those due to insect stings.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Clinical & experimental allergy 20 (1990), S. 0 
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Lesional (n= 15) and non-lesional (n= 10) skin of subjects with mastocytosis was analysed for the distribution and concentration of trypase positive, chymase negative mast cells (MCT) and tryptase positive, chymase positive mast cells (MCTC) cells and compared to normal skin (n= 23) and non-lesional skin of subjects with unexplained anaphylaxis or flushing episodes (n= 6). Skin biopsies were fixed in Carney's fluid and subjected to double immunohistochemical staining with biotinylated mouse monoclonal anti-chymase antibody followed by alkaline phosphatase-conjugated mouse monoclonal anti-tryptase antibody. MCTC cells were the only type of mast cells seen in all specimens analysed and in each case were more numerous in superficial compared to deep regions of dermis. The concentration (mean ± s.d.) of mast cells in the superficial dermis of mastocytosis lesions (40985 ± 21772 mast cells/mm3) was significantly increased over that in corresponding areas of non-lesional skin from subjects with mastocytosis (7178 ± 3607 mast cells/mm3), skin from subjects with idiopathic anaphylaxis or flushing episodes (6974 ± 3873 mast cells/mm3) and normal skin (7347 ± 2973 mast cells/mm3). The exclusive presence of MCTC cells in skin lesions of mastocytosis which are characterized by non-malignant hyperplasia of mast cells suggests involvement of local tissue factors in mast cell recruitment and differentiation.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Clinical & experimental allergy 18 (1988), S. 0 
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The effect of tryptase, a neural protease released from human lung mast cell secretory granules, on purified human Hageman Factor(Factor XII) was examined. No increase in Hageman Factor enzymatic activity was detected after incubation with tryptase at 37°C; activation of Hageman Factor by bovine trypsin served as a positive control. Furthermore, pre-incubation of Hageman Factor with tryptase did not diminish the subsequent activation of Hageman Factor by trypsin. Polyacrylamide gel electrophoresis was also performed to show that incubation with tryptase does not alter the molecular weight of Hageman Factor. Therefore, tryptase neither activates nor destroys human Hageman Factor.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background The combination of recombinant human stem cell factor (rhSCF), rh interleukin (IL)-6 and rhIL-10 was reported to be optimal for mast cell development from cord blood progenitors and to induce chymase expression in all such mast cells earlier in their development than tryptase.Objective The effects of rhIL-6 and rhIL-10 in various combinations on the rhSCF-dependent development of human mast cells from fetal liver progenitors were examined in serum-free media.Methods Dispersed fetal liver cells were cultured in serum-free AIM-V medium with rhSCF alone, or with combinations of rhIL-6 and rhIL-10. Tryptase and chymase expression, surface Kit expression, metachromasia with toluidine blue and apoptosis were measured.Results Neither rhIL-6 nor rhIL-10 nor the two interleukins together, when included from day 0 of culture, affected the number or protease phenotype of mast cells at 1 or 3 weeks. Expression of tryptase paralleled the appearance of metachromasia and surface Kit, both of which preceded chymase expression, regardless whether a rabbit polyclonal or mouse monoclonal anti-chymase antibody preparation was used. On the other hand, rhIL-6 markedly attenuated baseline levels of apoptosis in the presence of rhSCF as well as apoptosis occurring after withdrawal of rhSCF, whereas rhIL-10 had no effect.Conclusion RhIL-6 protected fetal liver-derived mast cells from apoptosis, particularly after withdrawal of rhSCF, but neither rhIL-6 nor rhIL-10 nor the combination of these interleukins affected the numbers or protease phenotype of these mast cells.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Clinical & experimental allergy 19 (1989), S. 0 
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Clinical & experimental allergy 34 (2004), S. 0 
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background Heparin-related immediate-type hypersensitivity reactions like urticaria, angio-oedema or bronchospasm are very rare, and only a few cases of anaphylaxis-like responses because of heparin have been described. However, the mechanisms underlying these reactions and the role of mast cells in their pathogenesis have not been elucidated.Objectives We report a patient with end-stage renal disease who presented with recurrent anaphylaxis after receiving heparin during haemodialysis. The underlying aetiology was obscured by the initiation of haemodialysis with its known anaphylactic-like side-effects. The diagnosis of hypersensitivity to heparin was confirmed by the clinical picture, positive skin tests and elevated serum tryptase levels.Materials and methods We performed prick and intradermal skin tests with heparin, enoxaparin and danaparoid heparinoid. Total and mature tryptase levels were measured in serum by ELISAs at 1, 24 and 36 h following the reaction.Results An elevated mature tryptase level was found at 1 h, which returned to normal levels at 24 and 36 h. A high total tryptase level was detected at 1 h, but remained somewhat elevated at 24 h. Prick tests were negative with the three compounds. Intradermal skin tests with heparin and enoxaparin were both positive, while with danaparoid negative. Following negative skin test results, danaparoid was used as an anticoagulant during dialysis for the next 3 years without any adverse effects.Conclusions In conclusion, we report the first case of heparin-induced anaphylaxis confirmed by an elevated level of mature tryptase in serum. Following skin tests, the patient was treated with danaparoid during haemodialysis sessions three times a week without any adverse effects. Because of increasing use of heparin in daily medical practice, physicians should be aware of possible immediate hypersensitivity reactions to this medication and know how to diagnose and treat them.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background In vitro-derived human mast cells exhibit different properties, depending in part on the source of progenitor cells. Most investigations have used fetal liver, cord blood or peripheral blood. Few have used adult bone marrow.Objective Human mast cells derived in vitro from the CD34+ progenitors in bone marrow and cord blood that had been cultured with recombinant human stem cell factor (rhSCF) and recombinant human interleukin-6 (rhIL-6) were compared.Methods and results After 12 weeks of culture, nearly all of the cells were mast cells, and nearly all of these had cytoplasmic granules containing both tryptase and chymase (MCTC type), stained metachromatically with acidic toluidine blue, and expressed CD117 on the cell surface. Both tryptase protein and mRNA were detected by two weeks of culture. Chymase mRNA and protein were detected at 4 weeks but not at 2 weeks of culture. By 12 weeks, chymase content per cell, measured by ELISA, was significantly higher (P 〈 0.05) in human bone marrow-derived mast cells (HBMMC) (5.6 ± 0.9 pg) than in cord blood-derived mast cells (CBMC) (2.4 ± 0.9 pg), whereas histamine and tryptase levels were not significantly different. Of the cluster designations tested, CD29, CD49d, CD51 and CD61 were strongly expressed on HBMMC. CD54 and FcεRIα also were expressed constitutively. Approximately half of CD34-sorted cells at day 0 were CD13+ and this diminished as mast cell maturation occurred. Electron microscopy revealed that 12-week-old HBMMC had many secretory granules that contained spherical electron dense cores surrounded by electron lucent space, consistent with previous reports of immature MCTC cells developing in vivo.Conclusions CD34+ progenitors of human bone marrow are a rich source of mast cell progenitors capable of expressing granule and surface markers of mature mast cells in the presence of rhSCF and rhIL-6.
    Type of Medium: Electronic Resource
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