Search results for "Dextran sulfate"
showing 10 items of 38 documents
Blood flow patterns spatially associated with platelet aggregates in murine colitis.
2009
In the normal murine mucosal plexus, blood flow is generally smooth and continuous. In inflammatory conditions, such as chemically-induced murine colitis, the mucosal plexus demonstrates markedly abnormal flow patterns. The inflamed mucosal plexus is associated with widely variable blood flow velocity as well as discontinuous and even bidirectional flow. To investigate the mechanisms responsible for these blood flow patterns, we used intravital microscopic examination of blood flow within the murine mucosal plexus during dextran sodium sulphate-and trinitrobenzenesulfonic acid-induced colitis. The blood flow patterns within the mucosal plexus demonstrated flow exclusion in 18% of the vessel…
Perforin deficiency attenuates inflammation and tumor growth in colitis-associated cancer
2010
Background: Patients with inflammatory bowel disease (IBD) have a markedly increased risk to develop colon cancer, but there are only limited data about the host antitumor response in such colitis-associated cancer. In the present study we aimed at assessing the role of perforin-dependent effector mechanisms in the immune response in a murine model of colitis-associated colon cancer. Methods: Wildtype and perforin-deficient mice were analyzed in a mouse model of colitis-associated colon cancer using azoxymethane (AOM) and dextran sodium sulfate (DSS). Results: Tumors of wildtype mice showed infiltration of CD4+, CD8+ T cells, natural killer (NK) cells, high numbers of apoptotic cells, and e…
Mast Cells Infiltrating Inflamed or Transformed Gut Alternatively Sustain Mucosal Healing or Tumor Growth.
2015
Abstract Mast cells (MC) are immune cells located next to the intestinal epithelium with regulatory function in maintaining the homeostasis of the mucosal barrier. We have investigated MC activities in colon inflammation and cancer in mice either wild-type (WT) or MC-deficient (KitW-sh) reconstituted or not with bone marrow-derived MCs. Colitis was chemically induced with dextran sodium sulfate (DSS). Tumors were induced by administering azoxymethane (AOM) intraperitoneally before DSS. Following DSS withdrawal, KitW-sh mice showed reduced weight gain and impaired tissue repair compared with their WT littermates or KitW-sh mice reconstituted with bone marrow-derived MCs. MCs were localized i…
Vascular Microarchitecture of Murine Colitis-Associated Lymphoid Angiogenesis
2009
In permissive tissues, such as the gut and synovium, chronic inflammation can result in the ectopic development of anatomic structures that resemble lymph nodes. These inflammation-induced structures, termed lymphoid neogenesis or tertiary lymphoid organs, may reflect differential stromal responsiveness to the process of lymphoid neogenesis. To investigate the structural reorganization of the microcirculation involved in colonic lymphoid neogenesis, we studied a murine model of dextran sodium sulfate (DSS)-induced colitis. Standard 2-dimensional histology demonstrated both submucosal and intramucosal lymphoid structures in DSS-induced colitis. A spatial frequency analysis of serial histolog…
An inducible mouse model of colon carcinogenesis for the analysis of sporadic and inflammation-driven tumor progression.
2007
Colorectal cancer is a life-threatening disease that can develop spontaneously or as a complication of inflammatory bowel diseases. Mouse models are essential tools for the preclinical testing of novel therapeutic options in vivo. Here, we provide a highly reliable protocol for an experimental mouse model to study the development of colon cancers. It is based on the mutagenic agent azoxymethane (AOM), which exerts colonotropic carcinogenicity. Repeated intraperitoneal administration of AOM results in the development of spontaneous tumors within 30 weeks. As an alternative option, inflammation-dependent tumor growth can be investigated by combining the administration of AOM with the inflamma…
Mode of interaction of different polyanions with the first (), the second (C2) and the fourth (C4) component of complement—II
1976
Abstract Dextran sulfate, polyvinyl sulfate, liquoid, heparin and Sp 54, ∗ (a pentosanpoly-sulfoester) prevented the uptake of C2 by EAC4b. In contrast to EAC 4 b 2 a , treatment of EAC4b2 with polyanions led to dissociation into EAC4b and C2. The inhibition of C2 uptake by polyanions could be reduced by increasing magnesium concentration to levels which are normally inhibitory, suggesting that Mg ++ ions are sequestered by these sulfated polyanions.
Digestive vacuole of Plasmodium falciparum released during erythrocyte rupture dually activates complement and coagulation.
2012
Abstract Severe Plasmodium falciparum malaria evolves through the interplay among capillary sequestration of parasitized erythrocytes, deregulated inflammatory responses, and hemostasis dysfunction. After rupture, each parasitized erythrocyte releases not only infective merozoites, but also the digestive vacuole (DV), a membrane-bounded organelle containing the malaria pigment hemozoin. In the present study, we report that the intact organelle, but not isolated hemozoin, dually activates the alternative complement and the intrinsic clotting pathway. Procoagulant activity is destroyed by phospholipase C treatment, indicating a critical role of phospholipid head groups exposed at the DV surfa…
Effects of Dextran Sulfate 500 on Cell-Mediated Resistance to Infection with Listeria monocytogenes in Mice.
1974
Injection of dextran sulfate 500 caused loss of antibacterial resistance. Mice became more susceptible to an infection with Listeria monocytogenes and were unable to develop antilisterial immunity after both active and passive immunization with passively administered spleen cells from Listeria -immune donors. Indirect evidence suggests that the phagocytic component of cell-mediated resistance to bacterial infection is the site of attack of dextran sulfate.
Morphological Changes Induced by Dextran Sulfate 500 in Mononuclear Phagocytes of Listeria-Infected Mice
1974
Morphological changes involving mononuclear phagocytes in Listeria -infected mice after treatment with dextran sulfate 500 were investigated. Mononuclear phagocytes in livers and spleens, both circulating monocytes and fixed macrophages, showed uptake of electron-dense material. Mononuclear phagocyte changes were most pronounced within granulomatous lesions, where many phagocytes showed large membrane-bound inclusions and extensive cellular damage. It is concluded that dextran sulfate 500 selectively damages mononuclear phagocytes and that, in listerial infection, dextran sulfate 500 renders mononuclear phagocytes unable to express cellular resistance.
Leptin: A pivotal mediator of intestinal inflammation in mice
2002
Abstract Background & Aims: In addition to acting as a regulator of food intake and energy expenditure, leptin can also modulate immune and inflammatory responses. The role of leptin in intestinal inflammation is the focus of the present study. Methods: Acute and chronic colitis were induced in leptin-deficient ob/ob or wild-type (WT) mice using dextran sulfate sodium (DSS) or trinitrobenzene sulfonic acid (TNBS). The severity of colitis was evaluated, and possible mechanisms were studied. Results: Leptin directly stimulates intraepithelial lymphocytes (IELs) and lamina propria mononuclear cells (LPMCs). In the DSS acute model, ob/ob mice exhibited a 72% reduction of colitis severity and sp…