bluuebunny/crossref_metadata_2025_split huggingface dataset:
Uncoupled regulation of leukotriene C4 synthase in platelets from aspirin‐intolerant asthmatics and healthy volunteers after aspirin treatment
Authors: Tornhamre S. , Ehnhage A. , Kölbeck K. G. , Edenius C. , Lindgren J. Å. 
Published: March 2003

Summary
Background We have reported that thromboxane A2 induces suppression of leukotriene (LT) C4 synthase activity in human platelets.Aim In the present study, we describe a mechanism whereby aspirin treatment can lead to increased formation of LTC4, which is a potent bronchoconstrictor and inflammatory mediator. This mechanism is also demonstrated to be present in platelets from aspirin‐intolerant asthmatics (AIA).Methods The effect of arachidonic acid or platelet agonists on LTC4 synthase activity was investigated in platelets obtained from healthy volunteers, aspirin‐intolerant asthmatics or aspirin‐tolerant asthmatics after in vivo treatment or in vitro pre‐incubation with aspirin.Results Incubation of normal platelets with arachidonic acid or collagen provoked approximately 50% reduction of platelet LTC4 synthase activity, as determined by the conversion of LTA4 to LTC4. However, the inhibitory effect of arachidonic acid or collagen was not observed after oral administration of aspirin prior to collection of the platelets. Arachidonic acid‐induced inhibition of LTC4 synthase activity was totally abolished in platelets collected from peripheral blood already 30 min after aspirin ingestion but was fully restored in platelets collected 3 to 7 days after the administration of aspirin. Treatment of platelet suspensions with aspirin in vitro dose‐dependently counteracted the suppressive effect of arachidonic acid on LTC4 formation, with total reversal at approximately 40 µm. In contrast, the major aspirin metabolite, salicylic acid did not alter arachidonic acid‐induced reduction of LTC4 synthase activity. Similarly, LTC4 synthase activity in platelets from AIA and aspirin‐tolerant asthmatics (ATA) was reduced by approximately 50% after pre‐treatment with arachidonic acid in vitro. Again the inhibitory effect was abolished when platelets were pre‐incubated in the presence of aspirin.Conclusion The results indicate that oral aspirin administration can lead to uncoupling of thromboxane A2‐dependent negative feedback mechanisms, which may normally restrict the production of cysteinyl leukotrienes. This mechanism can be of potential interest in aspirin‐induced asthma.
Zafirlukast has no beneficial effects in the treatment of chronic urticaria
Authors: Reimers A. , Pichler C. , Helbling A. , J. Pichler W. , Yawalkar N. 
Published: March 2003

SummaryBackground Leukotriene receptor antagonists have shown some efficacy in the treatment of asthma. Injection of LTC4, LTD4 and LTE4 into the skin leads to a weal‐and‐flare reaction, suggesting an involvement of leukotrienes in the pathogenesis of urticaria. Indeed, various reports have indicated a beneficial effect for leukotriene receptor antagonists in patients with chronic urticaria.Objective To determine the therapeutic effect of the leukotriene receptor antagonist zafirlukast in patients with chronic urticaria.Methods The study was a double‐blind, placebo‐controlled, cross‐over study lasting for 12 weeks. Fifty‐two patients with chronic urticaria were investigated at a university hospital. The patients were randomized to receive 20 mg zafirlukast b.i.d. or placebo and cross‐over was scheduled after 6 weeks. The efficacy of the treatment was evaluated by a daily symptom score, six physical examinations, the requirement of rescue antihistamines (acrivastine) and an overall assessment by the patient and the investigating physician.Results Forty‐six patients completed the study: zafirlukast was well tolerated without alteration of the investigated laboratory parameters. In comparison with placebo, treatment with zafirlukast resulted in no significant positive effect for any of the efficacy measures. Moreover, we were unable to identify any subgroup of patients with chronic urticaria responding with a therapeutic benefit.Conclusions The leukotriene receptor antagonist zafirlukast does not provide a significant therapeutic benefit at a dose of 20 mg b.i.d. in patients with chronic urticaria.
Tumour necrosis factor‐α‐induced expression of intercellular adhesion molecule‐1 on human eosinophilic leukaemia EoL‐1 cells is mediated by the activation of nuclear factor‐κB pathway
Authors: Ip W. K. , Wong C. K. , Lam C. W. K. 
Published: March 2003

SummaryBackground Intercellular adhesion molecule‐1 (ICAM‐1) has been shown to mediate the adhesion and migration of eosinophils to the site of allergic inflammation. However, molecular mechanisms regulating the expression of ICAM‐1 in eosinophils are still being elucidated. We investigated the effect of tumour necrosis factor‐alpha (TNF‐α) on ICAM‐1 expression of eosinophils.Methods The surface expression of ICAM‐1 on a human eosinophilic leukaemic cell line, EoL‐1, was assessed by immunocytochemical staining. The phosphorylation of inhibitor kappa B‐alpha (IκB‐α) and p38 mitogen‐activated protein kinase (MAPK) was detected by Western blot. Nuclear factor kappa‐B (NF‐κB) pathway‐related genes were evaluated by the cDNA expression array system, whereas the activity of NF‐κB was measured by electrophoretic mobility shift assay (EMSA).Results TNF‐α was found to induce the cell surface expression of ICAM‐1. A specific proteasome inhibitor N‐cbz‐Leu‐Leu‐leucinal (MG‐132), but not a p38 MAPK inhibitor (SB 203580), was found to suppress the TNF‐α‐induced expression of ICAM‐1 on EoL‐1 cells. The gene expressions of ICAM‐1, NF‐κB and IκBα were up‐regulated after the stimulation with TNF‐α. Further, TNF‐α was shown to induce IκB‐α phosphorylation and degradation, thereby indicating the activation of NF‐κB. In EMSA, there was a shifted NF‐κB band on TNF‐α‐treated cells with or without SB 203580, but no shifted band was observed on MG‐132‐treated cells.Conclusion In vitro studies of EoL‐1 cells, an eosinophilic leukaemic cell line, confirmed that NF‐κB plays an important role in the expression of ICAM‐1 and recruitment of eosinophils in allergic inflammation.
Indirect demonstration of the lifetime function of human thymus
Authors: Marušić M , Turkalj-Kljajić M , Petrovečki M , Užarević B , Rudolf M , Batinić D , Ugljen R , Anić D , Ćavar Z , Jelić I , Malenica B 
Published: March 2003

SUMMARYThe aim of this study was to test the hypothesis that human thymus maintains its function as the site of early T cell development throughout life, but to a progressively diminishing extent. Mononuclear cell suspensions prepared from the samples of 39 human thymuses were analysed for the total number of cells per gram of thymus tissue, percentage of single marker-positive CD2, CD4 and CD8 cells, percentages of double-positive CD4 CD8 and CD2 CD8 cells, double-negative CD4 CD8 cells, absolute numbers of these cells per gram of tissue, and extent of the in vitro proliferation upon stimulation with concanavalin A (Con A), phytohaemagglutinin (PHA) and pokeweed mitogen (PWM) mitogens. The main outcome measures were flow cytometric data on thymus lymphoid cell composition (according to CD classification), expressed as percentages and numbers of cells per gram of thymus tissue. The total number of mononuclear cells expressed per gram of thymus tissue exponentially decreased with age. The slope of none of the analysed cell subpopulations differed from the slope of the line constructed for age-related decline of the total number of mononuclear cells (−0.024 on a semilogarithmic scale). The thymuses of all ages contained all analysed cell subpopulations in approximately the same proportions: percentages of these cell subpopulations did not change with age, except for all CD4+ (P = 0.017) and double-positive CD4+ CD8+ (P = 0.016) cells, which tended to decrease with age. The extent of proliferation of thymus cells upon stimulation with T and B cell mitogens was unrelated to age. We conclude that the thymus retains its function as the site of differentiation of T lymphocytes throughout life. With respect to the number of involved lymphoid cells, the function exponentially decreases with age.
β2-Glycoprotein I-dependent and -independent anticardiolipin antibody in non-obese diabetic (NOD) mice
Authors: Anzai K , Nagafuchi S , Niho Y , Kikuchi M , Ono J 
Published: March 2003

AbstractIn the present study we investigate whether or not anticardiolipin antibody (aCL) is produced in NOD mice, which is a representative animal model of insulin-dependent diabetes mellitus (IDDM). We found that IgG class aCL appeared in 6.9% of non-diabetic NOD mice at weeks 5–15. The rates increased with age to 31.6% at weeks 16–25 and 71.9% at weeks 26–35. In addition, the titre and incidence of aCL were higher in diabetic mice than in non-diabetic mice. It was also found that aCL in NOD mice involved β2-glycoprotein I (β2-GPI)-dependent and -independent aCL, when β2-GPI was added to the aCL assay system. The IgG subclass of both β2-GPI-dependent and -independent aCL belonged exclusively to IgG2a. In addition, immunohistochemical studies revealed the predominant accumulation of IgG2a- or IgG3-positive B lymphocytes within insulitis. These results suggest that the autoimmunity in NOD mice may thus be associated with Th1 predominant immunological response. In conclusion, aCL with multiple antigenic specificity were produced in NOD mice along with the development of insulitis and diabetes. NOD mice should thus be added to the list of animal models possessing antiphospholipid antibody.
Effects of adjuvants on the immune response to allergens in a murine model of allergen inhalation: cholera toxin induces a Th1-like response to Bet v 1, the major birch pollen allergen
Authors: Wiedermann U , Jahn-Schmid B , Fritsch R , Bauer L , Renz H , Kraft D , Ebner C 
Published: March 2003

AbstractBased on the fact that type I allergies are frequently elicited by inhalant allergens, we have established a model of aerosol inhalation leading to allergic sensitization in BALB/c mice. Using this model we studied the effects of aluminium hydroxide (Al(OH)3), known to enhance IgE antibody responses, compared with cholera toxin (CT), a potent mucosal adjuvant, on the immune response to birch pollen (BP) and its major allergen Bet v 1. Two groups of BALB/c mice were either systemically immunized with recombinant Bet v 1 in Al(OH)3 and subsequently aerosol exposed to BP allergen, or aerosolized with BP and CT. IgE-mediated skin reactions were only elicited in the mice which had received Bet v1/Al(OH)3. Allergen-specific serum IgE and IgG1 antibodies dominated in the Al(OH)3 group, IgG2a antibody levels to BP and rBet v 1 were markedly higher in the sera of mice exposed to CT with the allergen. IgA antibodies were only detected in the bronchial lavage of the CT-treated group. Moreover, the latter group displayed consistently higher T cell proliferative responses to BP and interferon-gamma production in vitro. Thus, the systemic immunization with rBet v 1 in Al(OH)3 before inhalation of the BP extract promoted a Th2-like immune response, while CT mixed with the aerosolized BP extract rather induced a Th1-like immune response. In an attempt to reverse these ongoing immune responses we could achieve a shift towards a Th0 response. Immunization with BP extract without adjuvant treatment led to undetectable antibody or cellular immune responses. We conclude from the present study that the induction of an immune response to BP allergen after aerosol inhalation can be directed towards a Th1- or a Th2-like response. Once established, the immune response can be modulated.
Spontaneous immunoglobulin-producing capacity of cultures from lupus patients and normal donors following depletion of cells expressing CD19 or CD38
Authors: Bourne T , Zukowska-Cooper M , Salaman M R , Seifert M H , Isenberg D A 
Published: March 2003

SUMMARYCells spontaneously secreting IgG or IgM (ISC) are present at a high level in the blood of patients with systemic lupus erythematosus (SLE). By use of magnetic-bead techniques, mononuclear cells from such patients and healthy donors were fractionated according to expression of CD19 or CD38 and the cell fractions were then cultured in the absence of added mitogen/antigen for 5/6 days. Supernatant IgG and IgM were determined and, in addition, in the CD38 experiments ISC were enumerated both before and after culture. Much of the immunoglobulin-producing capacity of unfractionated cells (UFC) from both donor groups was recovered in the CD19− fraction, and no immunoglobulin was produced by CD19+ cells suggesting, unexpectedly, that ISC were not expressing CD19. By contrast, CD38 fractionation resulted in nearly all ISC passing to the CD38+ fraction which produced levels of immunoglobulin approaching 50% that of UFC. On culture of CD38− cells there was a build up in the number of IgG and IgM ISC, this being particularly striking in the controls with numbers well in excess of those in UFC. Not all these new ISC became CD38+, but the maturation process was more efficient in the SLE patients. The possibility is discussed that the spontaneous response in the CD38− populations is due to removal of CD38+ natural killer (NK) cells. Removal of ISC that are present preculture is a helpful initial step in studying ISC generation in the disease.
1,25-Dihydroxyvitamin D3 restores sensitivity to cyclophosphamide-induced apoptosis in non-obese diabetic (NOD) mice and protects against diabetes
Authors: Casteels K , Waer M , Bouillon R , Depovere J , Valckx D , Laureys J , Mathieu C 
Published: March 2003

SUMMARYThe activated form of vitamin D, 1,25(OH)2D3, and its analogues can prevent type I diabetes in NOD mice. Protection is achieved without signs of systemic immunosuppression and is associated with a restoration of the defective immune regulator system of the NOD mice. The aim of the present study was to investigate whether this restoration of regulator cell function is the only mechanism in the prevention of diabetes by 1,25(OH)2D3. We tested therefore if 1,25(OH)2D3 could prevent cyclophosphamide-induced diabetes, since diabetes occurring after cyclophosphamide injection is believed to be due to an elimination of suppresser cells. NOD mice treated with 1,25(OH)2D3 (5 μg/kg every 2 days) from the time of weaning were clearly protected against diabetes induced by cyclophosphamide (200 mg/kg body wt at 70 days old) (2/12 (17%) versus 36/53 (68%) in control mice, P &lt; 0.005). By co-transfer experiments it was demonstrated that cyclophosphamide had indeed eliminated the suppresser cells present in 1,25(OH)2D3-treated mice. Since cyclophosphamide injection did not break the protection offered by 1,25(OH)2D3, it was clear that diabetogenic effector cells were affected by 1,25(OH)2D3 treatment as well. This was confirmed by the finding that splenocytes from 1,25(OH)2D3-treated mice were less capable of transferring diabetes in young, irradiated NOD mice, and by the demonstration of lower Th1 cytokine levels in the pancreases of 1,25(OH)2D3-treated, cyclophosphamide-injected mice. This better elimination of effector cells in 1,25(OH)2D3-treated mice could be explained by a restoration of the sensitivity to cyclophosphamide-induced apoptosis in both thymocytes and splenocytes, in normally apoptosis-resistant NOD mice. Altogether, these data indicate that the protection against diabetes offered by 1,25(OH)2D3 may be independent of the presence of suppresser cells, and may involve increased apoptosis of Th1 autoimmune effector cells.
Cloning and characterization of a latex allergen (Hev b7): homology to patatin, a plant PLA2
Authors: Kostyal D A , Hickey V L , Noti J D , Sussman G L , Beezhold D H 
Published: March 2003

SUMMARYWe previously identified a 46-kD protein allergen in latex as having amino acid sequence homology to the patatin gene family. The objective of this study was to characterize this protein by molecular techniques. RNA was isolated from the latex or leaf material from Hevea brasiliensis and from potato tubers. Specific polymerase chain reaction (PCR) primers were designed from the amino acid sequence and reverse transcriptase (RT)-PCR amplified a specific product from latex RNA that was subsequently cloned and sequenced. This product was 1493 bp in length with an 1167 bp open reading frame. The deduced amino acid sequence encodes for a 389 aa protein, pI 4.82 with 43% homology to tobacco patatin. Northern analysis of potato, Hevea leaf, and latex RNA demonstrated the message to be most abundant in latex, weakly present in Hevea leaf, but no hybridization occurred with potato RNA. Patatin has lipid acyl-transferase and PLA2-like activity, suggesting it plays a role as a defence-related protein. Other defence-related proteins in latex such as hevein, glucanase, and hevamine are also allergens. Increased production of defence-related proteins as a result of increased tapping of the rubber trees to meet the demand for latex may explain the increased allergenicity of latex.
Tumour-specific cytotoxic T lymphocyte activity in Th2-type Sézary syndrome: its enhancement by interferon-gamma (IFN-γ) and IL-12 and fluctuations in association with disease activity
Authors: Seo N , Tokura Y , Matsumoto K , Furukawa F , Takigawa M 
Published: March 2003

SUMMARYSézary syndrome (SzS) is the leukaemic variant of cutaneous T cell lymphoma (CTCL), whose malignant T cells are of the Th2 type in most cases. In this study we investigated the tumouricidal activity of cytotoxic T lymphocytes (CTL) present in peripheral blood of a patient with Th2-type SzS, focusing on the effect of IL-2, IFN-γ and IL-12 on their cytotoxic activity, and the relationship between their lytic capacity and the patient's clinical course. At four different time points during a 2-month clinical period, CD4+ CD7− Sézary cells and CD8+ cells were separated from the patient's circulating cells. CD8+ cells were cultured with chemically attenuated, purified Sézary cells in the presence of IL-2 to develop specific cytotoxicity. The CD8+ cells thus cultured exhibited lytic activity against autologous Sézary cells. Concomitant addition of IFN-γ or IL-12 exerted a synergistic cytolytic effect with IL-2 on the tumour cells. Cytotoxicity inhibition studies using MoAbs revealed that the cytotoxicity operated in MHC class I-, CD8- and αβ T cell receptor-dependent manners. Furthermore, eight CD8+ T cell clones generated from cultured CD8+ cells exhibited a strong cytotoxicity against Sézary cells in an MHC class I-restricted fashion. During the clinical course, the activity of generated CTL and the number of CD8+ cells were inversely correlated with disease activity as assessed by the serum level of lactate dehydrogenase. These findings suggest that CTL down-regulate the growth of malignant T cells in this long-standing disease. Since Th2 cytokines such as IL-4 down-modulate CTL activity, CTL are assumed to be usually suppressed in SzS, whose malignant T cells are of Th2 type. It is likely that the administration of IFN-γ normalizes this Th2-skewing state, activates CTL, and thus exerts the therapeutic effectiveness in the treatment of CTCL.
Autoimmune thrombocytopenia (AITP) and thyroid autoimmune disease (TAD): overlapping syndromes?
Authors: Cordiano I , Betterle C , Spadaccino C A , Soini B , Girolami A , Fabris F 
Published: March 2003

SUMMARY
The pathogenesis of thrombocytopenia associated with TAD and the occurrence of overlapping traits between TAD and AITP are still a matter of debate. For this reason, we investigated for the presence and specificity of platelet and thyroid autoantibodies in 18 TAD patients with thrombocytopenia, 19 TAD patients without thrombocytopenia and in 22 patients with primary AITP without clinical signs of TAD. Platelet-associated IgG and/or specific circulating platelet autoantibodies were detected in 83% of patients with TAD and thrombocytopenia, in 10% of patients with TAD without thrombocytopenia and in 86% of patients with primary AITP. The reactivity of serum autoantibodies, assayed by MoAb immobilization of platelet antigens (MAIPA), was directed against platelet glycoproteins Ib and/or IIb/IIIa in 50% of the patients with TAD and thrombocytopenia, as in 46% of the patients with primary AITP. Thyroid autoantibodies were found in 89% of patients with TAD and thrombocytopenia, in 95% of patients with TAD without thrombocytopenia, and in 18% of patients with primary AITP. Thyrotropin (TSH) levels determined in three of four AITP patients with thyroid autoantibodies revealed a subclinical hyperthyroidism in one patient. The present study supports the autoimmune aetiology of thrombocytopenia associated with TAD, since the prevalence and specificity of platelet autoantibodies are similar in TAD and primary AITP. The results indicate also that there exists an overlap between thyroid and platelet autoimmunity with or without clinical manifestations.
Scleroderma fibroblasts promote migration of mononuclear leucocytes across endothelial cell monolayers
Authors: Denton C P , Shi-Wen X , Sutton A , Abraham D J , Black C M , Pearson J D 
Published: March 2003

SUMMARYPerivascular infiltrates of inflammatory cells are a hallmark of lesional skin in scleroderma. We have explored the potential for scleroderma fibroblasts to modulate mononuclear leucocyte migration across endothelial cell monolayers in tissue culture, and to regulate expression of endothelial cell adhesion molecules. Fibroblasts were grown from skin biopsies of eight patients with active diffuse cutaneous scleroderma and from four healthy controls. Co-culture and conditioned medium transfer experiments examined the effect of soluble fibroblast products on mononuclear leucocyte (U937) cell migration across endothelial cell (1E-7) monolayers grown on tissue culture inserts. Co-culture of scleroderma, but not control fibroblasts, promoted transendothelial migration of U937 cells. Scleroderma fibroblast-conditioned medium had qualitatively similar effects and equivalent results were obtained using Jurkat-6 (T lymphocyte) cells, and with peripheral blood mononuclear cells from a patient with diffuse cutaneous scleroderma. Promotion of leucocyte migration does not appear to result from increased endothelial adhesion molecule expression, since fibroblast-conditioned medium did not up-regulate endothelial cell expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) or E-selectin. Moreover, leucocyte migration across cytokine-activated endothelial cell layers in co-cuture with fibroblasts was less than across resting cells, although the selective effect of scleroderma fibroblast co-culture persisted. Recombinant monocyte chemoattractant protein-1 (MCP-1) or IL-8 increased passage of mononuclear leucocytes across endothelial cell monolayers, whilst anti-MCP-1, but not anti-IL-8 antibodies, significantly reduced the effect of fibroblast conditioned medium. These data suggest that systemic sclerosis (SSc) fibroblasts promote leucocyte migration across endothelial cell monolayers in tissue culture via an MCP-1-dependent mechanism. These findings may be relevant to the perivascular mononuclear leucocyte infiltrates characteristic of early SSc lesions.