Search results for "Degranulation"

Kalanchoe pinnata inhibits mast cell activation and prevents allergic airway disease

2011

Aqueous extract of Kalanchoe pinnata (Kp) have been found effective in models to reduce acute anaphylactic reactions. In the present study, we investigate the effect of Kp and the flavonoid quercetin (QE) and quercitrin (QI) on mast cell activation in vitro and in a model of allergic airway disease in vivo. Treatment with Kp and QE in vitro inhibited degranulation and cytokine production of bone marrow-derived mast cells following IgE/FcɛRI crosslinking, whereas treatment with QI had no effect. Similarly, in vivo treatment with Kp and QE decreased development of airway hyperresponsiveness, airway inflammation, goblet cell metaplasia and production of IL-5, IL-13 and TNF. In contrast, treatm…

Effect of imidazo[1,2-α]pyrimidine derivatives on leukocyte function

2001

Objective and Design: A series of six imidazo[1,2-α]pyrimidine (IP) derivatives were evaluated for their effects on leukocyte functions in vitro as well as on the inflammatory response induced by zymosan in the mouse air pouch.¶Materials and Subjects: Human neutrophils and murine peritoneal macrophages were used for in vitro assays. Mouse air pouch was performed in Swiss mice.¶Treatment: Test compounds were incubated with either human neutrophils or mouse peritoneal macrophages at concentrations not showing cytotoxic effects. For in vivo experiments, IPs were injected into the air pouch.¶Methods: Elastase and myeloperoxidase release, superoxide generation and LTB4 production were assayed in…

Effect of some hexahydroimidazo[1,2-c]pyrimidines in inflammatory responses involving leucocytes and macrophages.

2001

Abstract We have studied the effects of some hexahydroimidazo[1,2-c]pyrimidine derivatives (HIPs) on leucocyte functions in-vitro and we have assayed the anti-inflammatory activity of these compounds in two models of inflammation. All HIPs inhibited the human neutrophil degranulation process and superoxide generation at concentrations in the μM range. In mouse peritoneal macrophages stimulated with lipopolysaccharide, HIP-4 and HIP-5 inhibited nitrite production without affecting prostaglandin E2 (PGE2) accumulation. HIP-4 was also active in the zymosan-injected mouse air pouch model (at 100 nmol/pouch), with significant reductions in leucocyte migration and PGE2 and leukotriene B4 levels i…

2014

The lungs are a noted predilection site of acute, latent, and reactivated cytomegalovirus (CMV) infections. Interstitial pneumonia is the most dreaded manifestation of CMV disease in the immunocompromised host, whereas in the immunocompetent host lung-infiltrating CD8 T cells confine the infection in nodular inflammatory foci and prevent viral pathology. By using murine CMV infection as a model, we provide evidence for a critical role of mast cells (MC) in the recruitment of protective CD8 T cells to the lungs. Systemic infection triggered degranulation selectively in infected MC. The viral activation of MC was associated with a wave of CC chemokine ligand 5 (CCL5) in the serum of C57BL/6 m…

Synthesis and evaluation of 2-tosylamino and 2-tosyliminopyrimidine derivatives as inhibitors of some leukocyte functions

2003

Abstract We have studied the potential anti-inflammatory effects of 20 2-tosylamino and 2-tosyliminopyrimidine new derivatives in human neutrophils. We have evaluated their interference with some leukocyte functions and 5-lipoxygenase activity. All the compounds reduced neutrophil degranulation process at concentrations in the μM range. Besides, compounds with a phenolic substitution inhibited leukotriene B 4 biosynthesis in neutrophils and decreased the cell-free 5-lipoxygenase activity. This study demonstrates that 2-tosylamino and 2-tosyliminopyrimidine derivatives can reduce the activation of neutrophil cells which may have relevance for the modulation of the inflammatory response.

Mast cells as rapid innate sensors of cytomegalovirus by TLR3/TRIF signaling-dependent and -independent mechanisms

2014

The succinct metaphor, ‘the immune system's loaded gun', has been used to describe the role of mast cells (MCs) due to their storage of a wide range of potent pro-inflammatory and antimicrobial mediators in secretory granules that can be released almost instantly on demand to fight invaders. Located at host–environment boundaries and equipped with an arsenal of pattern recognition receptors, MCs are destined to be rapid innate sensors of pathogens penetrating endothelial and epithelial surfaces. Although the importance of MCs in antimicrobial and antiparasitic defense has long been appreciated, their role in raising the alarm against viral infections has been noted only recently. Work on cy…

Effect of bakuchiol on leukocyte functions and some inflammatory responses in mice.

1996

Abstract The effects of bakuchiol, a meroterpenoid isolated from the leaves of Psoralea glandulosa L., on phospholipase A2 (PLA2) activity from different sources, human neutrophil responses, zymosan air pouch and topical inflammation in mice, were investigated. This natural product was a weak inhibitor of secretory and intracellular PLA2 but dose-dependently reduced the formation of LTB4 and TXB2 by human neutrophils and platelet microsomes, respectively. In addition, bakuchiol inhibited degranulation in human neutrophils, whereas superoxide generation was not affected. In mice, bakuchiol decreased cell migration, myeloperoxidase activity and eicosanoid levels in the air pouch inflammation …

Mast cell targeting hampers prostate adenocarcinoma development but promotes the occurrence of highly malignant neuroendocrine cancers

2011

Abstract Mast cells (MC) are c-Kit–expressing cells, best known for their primary involvement in allergic reactions, but recently reappraised as important players in either cancer promotion or inhibition. Here, we assessed the role of MCs in prostate tumor development. In prostate tumors from both tumor-prone transgenic adenocarcinoma of the mouse prostate (TRAMP) mice and human patients, MCs are specifically enriched and degranulated in areas of well-differentiated (WD) adenocarcinoma but not around poorly differentiated (PD) foci that coexist in the same tumors. We derived novel TRAMP tumor cell lines, representative of WD and PD variants, and through pharmacologic stabilization or geneti…

Inhibition of phospholipase A2 activities and some inflammatory responses by the marine product ircinin

1996

The marine product ircinin has been tested for its effects on secretory and cytosolic phospholipase A2 (PLA2) activities in vitro as well as for inhibition of cellular functions in human neutrophils and inflammatory responses in mice. Ircinin inhibited Naja naja venom, human synovial recombinant, bee venom and zymosan-injected rat air pouch PLA2 with IC50 values in the microM range, similar to those of the known inhibitor scalaradial. On the other hand, ircinin was less active on cytosolic PLA2 from human monocytes and decreased potently the release of LTB4 in human neutrophils. This marine product affected weakly human neutrophil functions like superoxide generation and degranulation. In t…

The basic structural lesion of persistent neonatal hypoglycaemia with hyperinsulinism: deficiency of pancreatic D cells or hyperactivity of B cells?

1984

Pancreatic tissue obtained at subtotal pancreatectomy from 15 infants with persistent hypoglycaemia with hyperinsulinism, and autopsy specimens from 23 age-matched normoglycaemic controls, were studied with morphometric methods after immunocytochemical staining of the four main islet cell types (A, B, D and pancreatic polypeptide cells). In three cases, a focal lesion was detected by gross examination. Macroscopic or microscopic examination did not distinguish the 12 other cases from controls. As found previously, nesidioblastosis was not a specific feature of the pancreas in infantile hypoglycaemia, being observed in age-matched controls as well. In cases with hypoglycaemia the volume dens…