Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tumor necrosis factor-alpha (TNF) is a cytokine released by mononuclear cells in response to inflammation and sepsis. Since the biological effects of TNF are consistent with the systemic and intestinal features of ulcerative colitis, the role of TNF was examined in a rabbit model of chronic colitis. Peripheral blood mononuclear cells were isolated, stimulated with lipopolysaccharide, and cultured supernatants assayed for TNF levels using a cytotoxic assay on mouse fibrosarcoma L929 cells. Basal levels of TNF production by mononuclear cells from 13 normal rabbits (124.3 units/ml +/- 27.1 units/ml, mean +/- SE) were not different from nine rabbits with colitis (83.6 units/ml +/- 24.4 units/ml, P > 0.05). Treatment with lipopolysaccharide (100 micrograms/ml) induced increased TNF production by mononuclear cells isolated from both normals (672.0 units/ml +/- 197.5 units/ml, P < 0.05) and rabbits with colitis (1114.0 units/ml +/- 489.6 units/ml, P < 0.05). However, at all lipopolysaccharide concentrations stimulated TNF levels were comparable in experimental and control groups (P > 0.05). In light of the role of leukotrienes in inflammation, a separate group of rabbits with colitis was investigated following treatment with an oral leukotriene B4 receptor antagonist. Serum TNF levels in 15 control rabbits (32.5 units/ml +/- 7.6 units/ml, mean +/- SE) were not significantly different from rabbits with colitis receiving either leukotriene B4 receptor antagonist (35.7 units/ml +/- 9.2 units/ml, N = 13) or vehicle alone (50.3 units/ml +/- 10.2 units/ml, N = 14) (ANOVA, P > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Systemic tumor necrosis factor-alpha production in experimental colitis. 133 Apr 61

There is a strong association between PSC and IBD. PSC is the most common hepatobiliary lesion seen in association with IBD. Whether there are two subsets of PSC, one associated with IBD and one unassociated, is controversial. A lower male to female ratio in patients without IBD supports this view. The demonstration of the haplotype DRw52a in 100% of patients with PSC, irrespective of the absence of IBD, speaks against this view. Patients with isolated PSC tend to present with jaundice, pruritus, and fatigue more frequently than those with combined PSC and IBD. There may also be a difference in bile duct involvement between patients with and without IBD combined with PSC. Apart from usually being a total colitis, either Crohn's colitis or UC, the IBD associated with PSC cannot be distinguished from IBD without PSC with respect to symptoms and clinical course. Patients with combined IBD and PSC may have somewhat worse prognosis than those with isolated PSC. The majority of patients developing BDC have concomitant IBD, suggesting that patients without IBD represent a different subgroup of PSC and run a different clinical course. Most studies have, however, found no differences in epidemiology, pathogenetic factors, clinical findings related to the hepatobiliary disease and prognosis between those who present with PSC alone and those who present with combined PSC and IBD. A major problem when discussing the relationship between IBD and PSC is that the bowel is inadequately examined in many of the studies relating to this question.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Relationship of inflammatory bowel disease and primary sclerosing cholangitis. 204 87

Twenty four sera from patients with haemolytic uraemic syndrome or haemorrhagic colitis and healthy controls were examined for antibodies to the lipopolysaccharide (LPS) of Escherichia coli O157. Faecal specimens from these patients were also examined for Vero cytotoxin producing E coli (VTEC) by DNA probes, and for faecal Vero cytotoxin. Eight patients with faecal E coli O157:H7 gave a strong antibody response to O157 LPS, shown by immunoblotting and an enzyme linked immunosorbent assay. Six symptomatic patients without evidence of faecal VTEC also gave a strong antibody response to O157 LPS. Sera from the remaining five patients and five healthy controls did not contain antibodies to E coli O157. The results suggest that the testing of sera from patients with haemorrhagic colitis or haemolytic uraemic syndrome by ELISA or immunoblot would prove valuable in addition to the established procedures for detecting VTEC, using DNA probes and testing for faecal Vero cytotoxin.
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PMID:Antibodies to Escherichia coli O157 in patients with haemorrhagic colitis and haemolytic uraemic syndrome. 267 53

Escherichia coli of serotype O157:H7 are Vero cytotoxin-producing enteric pathogens that have recently been associated with outbreaks of haemorrhagic colitis, sporadic cases of haemorrhagic colitis and with the haemolytic uraemic syndrome. The organisms demonstrate attaching and effacing binding to the caecum and colon of orally infected gnotobiotic piglets, chickens and infant rabbits. E. coli O157:H7 cells adhere to the surface but do not invade the cytoplasm of human epithelial cell lines in tissue culture. Since outer membranes, lipopolysaccharides and flagella have been identified as bacterial adhesins on other enteric pathogens, we evaluated their roles in the binding of non-fimbriated E. coli O157:H7 to HEp-2 cells. Hyperimmune rabbit antisera were prepared to whole cells, outer membranes and flagella of E. coli O157:H7. The presence of antibody to homologous antigen was confirmed by dot blot immunoassays. Both antisera and purified outer membrane and flagellar antigens were co-incubated with bacteria and HEp-2 cells to quantitate inhibition of bacterial attachment. Adherence of E. coli O157:H7 to tissue culture cells was inhibited by rabbit antisera raised to whole cells (76.0 +/- 5.6% inhibition compared with bacterial adherence in the presence of pre-immune rabbit serum) and outer membranes (69.2 +/- 3.4% inhibition). In contrast, inhibition of bacterial attachment to tissue-culture cells was significantly less when two antisera to H7 flagella were co-incubated with E. coli O157:H7 and HEp-2 cells (12.4 +/- 7.6%; 6.0 +/- 3.5% inhibition). Outer-membrane extracts inhibited adherence to E. coli O157:H7 to HEp-2 cells in a concentration dependent manner whereas isolated flagella and lipopolysaccharide antigens did not inhibit bacterial attachment.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Adherence of Vero cytotoxin-producing Escherichia coli of serotype O157:H7 to human epithelial cells in tissue culture: role of outer membranes as bacterial adhesins. 328 72

An experimental animal model of human ulcerative colitis using lipopolysaccharide (LPS) was studied. Rabbits were skin-sensitized by LPS and challenged with intrarectal instillation of LPS after 1% formalin enema. The course of experimental colitis was followed by performing serial colonofiberscopic examinations and biopsy. Petechiae appeared from the 8th hour, and ulcers and bleeding on the 3rd day. Mild macroscopic changes continued for about 2 weeks. By repeating the LPS enema after the initial treatment, the colitis was maintained for over 1 month. Control groups without formalin enema revealed no macroscopic changes, and the groups with only formalin enema showed mild transient changes. The endotoxin level in the blood during the experiment increased (36 pg/ml) at 24 h after the treatment in the LPS-sensitized group, while non-sensitized control rabbits had higher levels of endotoxin. Though fibrinogen and PTT levels had increased at 24 and 72 h, these levels were marked in the control rabbits. The direct reaction of LPS was minimal, and local immune reaction by LPS seems to play an important role in the perpetuation of experimental colitis. Tissue fibrinolysis of the colon increased significantly as the mucosal damage appeared. This experimental colitis with LPS may be useful as a model of human ulcerative colitis.
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PMID:Lipopolysaccharide-induced colitis in rabbits. 396 Dec 78

A murine pulmonary model was used to study the mucosal immune response to Shigella flexneri serotype 2a infection. Inoculation of BALB/cJ mice with shigellae via the intranasal route resulted in bacterial invasion of bronchial and alveolar epithelia with concomitant development of acute suppurative bronchiolitis and subsequent development of lethal pneumonia. The pathology of pulmonary lesions resembled the colitis that characterizes shigellosis in humans and primates. Significant protection against a lethal dose of S. flexneri 2a was observed in mice previously infected with two sublethal doses of the homologous strain. Immunity against lethal challenge was associated with decreased bacterial invasion of the mucosal epithelium. Over the course of two sublethal challenges, which constituted primary and secondary immunizations, mice developed pulmonary and serum immunoglobulin G and A antibody recognizing both lipopolysaccharide and invasion plasmid antigens IpaB and IpaC. Immune mice and naive control mice differed in lung lavage cytokine levels following lethal challenge. Immune mice developed significantly elevated levels of pulmonary gamma interferon within 6 h of challenge, while naive control mice developed elevated levels of this cytokine later during the initial 24-h period. Both groups had elevated levels of gamma interferon during the 24- to 48-h period of infection. Both groups also had elevated levels of tumor necrosis factor alpha within 6 h of challenge, but the control mice had significantly higher levels at the 48- and 72-h time points. Elevated levels of interleukin-4 were observed only in immunized mice. This cytokine appeared within 24 h and receded between 48 and 72 h. Fluorescence-activated cell sorter analysis of lung parenchymal cells showed that both groups experienced an initial influx of monocytes, but the proportion of this cell type began to recede in immunized mice after 48 h of infection, while peak levels were maintained in the control animals. These studies suggest that elements of local B lymphocyte activity, as well as Th1 and Th2 lymphocyte activity, may contribute to the survival of immune mice after intranasal challenge with shigellae.
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PMID:Antibody and cytokine responses in a mouse pulmonary model of Shigella flexneri serotype 2a infection. 772 7

Recent work suggests that thromboxanes may play a major pathogenic role in inflammatory bowel disease. Thromboxanes are produced in excess not only in inflamed mucosa but also in Crohn's disease, by uninflamed bowel and by isolated intestinal and peripheral blood mononuclear cells. Their cellular source is likely to include platelets, neutrophils, endothelial and epithelial cells as well as mononuclear cells, possible stimuli to their overproduction being chemotactic peptides, lipopolysaccharide, leukotrienes, platelet activating factor, interleukin-1, bradykinin and angiotensin II. The pro-inflammatory effects of thromboxanes are both direct (diapedesis and activation of neutrophils, mucosal ulceration, reduction of suppressor T-cell activity) and indirect (vasoconstriction, platelet activation). Although corticosteroids and aminosalicylates inhibit thromboxane synthesis, this action does not necessarily explain their therapeutic effect in inflammatory bowel disease. Selective thromboxane synthesis inhibitors and receptor antagonists, however, ameliorate experimental colitis in animals. Picotamide and ridogrel are dual thromboxane pathway blockers already used in man. Drugs of this type could prove useful not only for the prevention of systemic thrombo-embolism but also for suppressing intestinal mucosal inflammation in patients with inflammatory bowel disease.
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PMID:Review article: thromboxanes in inflammatory bowel disease--pathogenic and therapeutic implications. 821 51

Cases of culture-confirmed clinically typical haemorrhagic colitis caused by verocytotoxin-producing (VT+) Escherichia coli O157 and age- and sex-matched control patients were examined for antibodies to E. coli O157. Serum samples from 28 cases and 34 patients in control group 1 were examined for VT1- and VT2-neutralising antibodies, E. coli O157 agglutinating antibodies, and by an enzyme immunoassay (EIA) technique for IgG antibodies against smooth lipopolysaccharide purified from E. coli O157 and for IgG antibodies against whole intact E. coli O157 cells. Differences between antibody titres were significant when compared by a Wilcoxon two-sample test for E. coli O157 agglutinating antibodies (p < 0.05) and IgG antibodies against whole cells (p < 0.001). The whole-cell EIA was used further to examine faecal samples from 93 cases and 47 patients in control group 2 for IgA antibodies. Elevated levels of faecal IgA specific for E. coli O157 were found in 59 (63.4%) of 93 cases but in only 10 (21.2%) of 47 control patients (p < 0.001); follow-up faecal samples from five cases all showed marked rises in levels of IgA that appeared to coincide with cessation of excretion of the organism. Detection of specific faecal IgA with a whole-cell EIA, although requiring further evaluation, may be a useful addition to tests currently available for the diagnosis of infection by VT+ E. coli O157.
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PMID:Detection of serum and faecal antibodies in haemorrhagic colitis caused by Escherichia coli O157. 824 58

Alterations in phenotype and function of intestinal macrophages occur in inflammatory bowel disease (IBD) but it is unclear whether these changes result from the recruitment of circulating monocytes to the intestine or from proliferation of resident intestinal macrophages. We sought to demonstrate the arrival of blood monocytes, the precursors of macrophages, in IBD mucosa. Peripheral blood mononuclear cells were isolated from 23 patients with clinically active intestinal inflammation (13 Crohn's disease, eight ulcerative colitis, two infective colitis), then radiolabelled with 99mtechnetium (Tc)-stannous colloid (n = 13) or 111indium (In)-oxine (n = 10) before re-injection and abdominal scanning. Four patients had demonstrable intestinal monocyte uptake using [99mTc]-stannous colloid, while six [111In]-oxine-labelled monocyte scans were positive. Uptake sites correlated with actively inflamed regions. Patients demonstrating monocyte uptake had been treated with corticosteroids for a significantly (P < 0.02) shorter duration (median 3 vs 20 days) than those with negative scans. There was no significant difference between positive and negative scans for disease category, clinical or histological disease, activity, or radioisotope used. Biopsies of inflamed mucosa from two patients suffering ulcerative colitis who had positive scans showed a high proportion of CD14-positive macrophages, 4-9% of which contained autoradiographic grains. These results demonstrate that blood monocytes are recruited to the mucosa of actively inflamed bowel, and suggest that this process may be inhibited by corticosteroids. Moreover, the phenotype of the recently-arrived monocytes indicates their susceptibility to stimulation by lipopolysaccharide, and suggests a mechanism for the continuing inflammation in the bacterial product-rich milieu of IBD.
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PMID:Direct evidence of monocyte recruitment to inflammatory bowel disease mucosa. 852 3

Interleukin 10 (IL-10) indirectly prevents antigen-specific T-cell activation, which is associated with downregulation of the antigen presentation and accessory cell functions of monocytes, macrophages, Langerhans cells and dendritic cells. In addition, IL-10 inhibits T-cell expansion by directly inhibiting IL-2 production by these cells. These properties of IL-10, together with its capacity to downregulate the production of proinflammatory cytokines and chemokines by activated monocytes, polymorphonuclear leucocytes and eosinophils, indicate that IL-10 is a potent immunosuppressant in vitro. IL-10 has similar activities in vivo. It inhibits lipopolysaccharide or staphylococcal enterotoxin B induced lethal shock in mice. In addition, IL-10 deficient mice develop chronic inflammatory bowel disease, which could be reduced, or prevented by IL-10 treatment. IL-10 also prevented the development of colitis in a SCID mouse model. Collectively, these data indicate that IL-10 has great potential therapeutical utility in the treatment of diseases, such as chronic inflammation, autoimmune diseases, transplant rejection, graft-versus-host disease and sepsis.
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PMID:Immunosuppressive and anti-inflammatory properties of interleukin 10. 854 Oct 28


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