Accidental fatal aflatoxicosis due to contaminated commercial diet in 50 dogs.

Aflatoxins, produced by Aspergillus spp., are toxic contaminants of stored grain. This study describes 50 dogs presented with foodborne aflatoxicosis. Common clinical signs included lethargy (78%), vomiting (76%), anorexia (74%), icterus (66%), depression (66%), melena (60%), haematuria (36%) and diarrhoea (36%). Common laboratory abnormalities included increased activities of aspartate aminotransferase (86%), alkaline phosphatase (84%) and alanine aminotransferase (79%), hypoantithrombinaemia (86%), prolonged prothrombin (PT, 82%) and activated partial thromboplastin times (aPTT, 80%), hyperbilirubinaemia (73%), hypocholesterolaemia (60%) hypoalbuminemia (47%) and thrombocytopenia (42%). Non-survivors had longer PT and aPTT and lower antithrombin (P<0.001) at presentation compared to survivors (23.8s vs.10.5; 37.9 vs.17.6s and 5% vs. 54%, respectively). Hyperbilirubinaemia (>56.6 µmol/L) and albumin concentration <32.5 g/L at presentation were risk factors for mortality (P<0.0001). Common complications included disseminated intravascular coagulation (58%), hepatic encephalopathy (35%) and acute kidney injury (4%). The mortality rate was 68%, suggesting that dogs with aflatoxicosis have poor prognosis.

Halofuginone inhibits NF-kappaB and p38 MAPK in activated T cells.

Halofuginone, a low molecular weight plant alkaloid, inhibits collagen alpha1 (I) gene expression in several animal models and in patients with fibrotic disease, including scleroderma and graft-versus-host disease. In addition, halofuginone has been shown to inhibit angiogenesis and tumor progression. It was demonstrated recently that halofuginone inhibits transforming growth factor-beta (TGF-beta), an important immunomodulator. The present study was undertaken to explore the effects of halofuginone on activated T cells. Peripheral blood T cells were activated by anti-CD3 monoclonal antibodies in the absence and presence of halofuginone and assessed for nuclear factor (NF)-kappaB activity, production of tumor necrosis factor alpha (TNF-alpha) and interferon-gamma (IFN-gamma), T cell apoptosis, chemotaxis, and phosphorylation of p38 mitogen-activated protein kinase (MAPK). A delayed-type hypersensitivity (DTH) model was applied to investigate the effect of halofuginone on T cells in vivo. Preincubation of activated peripheral blood T cells with 10-40 ng/ml halofuginone resulted in a significant dose-dependent decrease in NF-kappaB activity (80% inhibition following incubation with 40 ng halofuginone, P = 0.002). In addition, 40 ng/ml halofuginone inhibited secretion of TNF-alpha, IFN-gamma, interleukin (IL)-4, IL-13, and TGF-beta (P < 0.005). Similarly, halofuginone inhibited the phosphorylation of p38 MAPK and apoptosis in activated T cells (P = 0.0001 and 0.005, respectively). In contrast, T cell chemotaxis was not affected. Halofuginone inhibited DTH response in mice, indicating suppression of T cell-mediated inflammation in vivo. Halofuginone inhibits activated peripheral blood T cell functions and proinflammatory cytokine production through inhibition of NF-kappaB activation and p38 MAPK phosphorylation. It also inhibited DTH response in vivo, making it an attractive immunomodulator and anti-inflammatory agent.

Induction of mast cell interactions with blood vessel wall components by direct contact with intact T cells or T cell membranes in vitro.

BACKGROUND: Mast cells exert profound pleiotropic effects on immune cell reactions at inflammatory sites, where they are most likely influenced not only by the extracellular matrix (ECM) and inflammatory mediators but also by the proximity of activated T lymphocytes. We recently reported that activated T cells induce mast cell degranulation with the release of TNF-alpha, and that this activation pathway is mediated by lymphocyte function-associated antigen-1 (LFA-1)/intercellular adhesion molecule-1 (ICAM-1) binding. OBJECTIVE: To determine how this contact between the two cell types can modulate mast cell behaviour in an inflammatory milieu by examining the adhesion of mast cells to endothelial cells and ECM ligands in an integrin-dependent manner. METHODS: Human mast cells (HMC-1) were co-cultured with resting or activated T cells followed by testing their adhesion to endothelial cell and ECM ligands, stromal derived factor-1alpha (SDF-1alpha)-induced migration, and western blotting. RESULTS: Co-culturing HMC-1 with activated, but not with resting T cells resulted in marked stimulation of mast cell adhesion to vascular cell adhesion molecule-1 and ICAM-1 in a very late antigen-4- and LFA-1-dependent fashion. In addition, activated T cells or T cell membranes promoted HMC-1 adhesion to fibronectin (FN) and laminin. This effect was accompanied by the phosphorylation of extracellular regulated kinase and p38, but not of c-Jun N-terminal kinase. Importantly, the adhesive property of mast cells depended exclusively on the direct contact between the two cell types, since neither supernatants from activated T cells nor separation of the two cell populations with a porous membrane affected mast cell adhesion to FN. Furthermore, similar results were obtained when mast cells were incubated with purified membranes from activated T cells. These results suggest that, in addition to stimulating mast cell degranulation, the proximity of activated T lymphocytes to mast cells can mediate the adhesion of mast cell precursors to the endothelial ligands and ECM. Activated T cells also stimulated SDF-1alpha-induced mast cell migration. CONCLUSION: This symbiotic relationship between the two types of immune cells may serve to direct mast cells to specific sites of inflammation where their effector functions are required.