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Query: UMLS:C0012739 (disseminated intravascular coagulation)
 8,673 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Platelet consumption is a prominent feature of disseminated intravascular coagulation. We investigated whether monocyte procoagulant activity (PCA) might play a role in platelet consumption associated with gram-negative septicemia. Human mononuclear cells exposed in vitro to lipopolysaccharide demonstrated parallel dose-dependent increases in PCA and ability to induce platelet aggregation. Induction of platelet aggregation required the generation of thrombin dependent on coagulation Factors VII, X, and II, and calcium. This is consistent with monocyte tissue factor initiating thrombin generation. A specific monoclonal antimonocyte antibody was used to identify monocytes via indirect immunofluorescence, and demonstrated that all monocytes were included in platelet aggregates. Mononuclear cells that did not express PCA did not induce platelet aggregation and monocytes were not surrounded by platelet clumps. These data suggest that monocytes induced to express tissue factor on their surface may be important mediators of endotoxin-induced platelet, as well as fibrinogen, consumption.
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PMID:Human platelet aggregation is initiated by peripheral blood mononuclear cells exposed to bacterial lipopolysaccharide in vitro. 353 97

Cultured human umbilical vein endothelial cells synthesize the procoagulant, tissue factor, after exposure to bacterial endotoxin. Wild-type lipopolysaccharide from Escherichia coli 0127:B8 stimulates a five- to 20-fold increase in cellular tissue factor. Similarly, rough or incomplete lipopolysaccharide subunits from mutant bacterial strains, or lipid A prepared by mild acid hydrolysis of whole endotoxin, are also stimulatory. In addition, a lipid A biosynthetic precursor, consisting of a phosphorylated glucosamine disaccharide substituted with four beta-hydroxymyristoyl residues, is stimulatory at nanomolar concentrations. Endothelial cell tissue factor is not detectable on the surface of undisrupted cells, but can activate clotting on the cell surface after oxidant-mediated cell injury. The procoagulant, tissue factor, is synthesized by endothelial cells after stimulation mediated by a moiety contained within the lipid A region of lipopolysaccharide. Exposure of clotting factors at the endothelial cell surface after cell injury suggests a mechanism for the microvascular thrombosis associated with disseminated intravascular coagulation with sepsis.
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PMID:Structural features of endotoxin required for stimulation of endothelial cell tissue factor production; exposure of preformed tissue factor after oxidant-mediated endothelial cell injury. 389 92

Endotoxin producing bacteria cause disseminated intravascular coagulation (DIC); however, the mechanism of endotoxin action in man is still unclear. Impairment of the fibrinolytic system has been suggested as a contributing mechanism. A single injection of Escherichia coli lipopolysaccharide in rabbits resulted in a marked and prolonged increase of the levels of a fast-acting inhibitor of plasminogen activator (PA-inhibitor) in plasma (from 3.9 +/- 0.7 to 41 +/- 13.2 U/ml after 3 h). Gel filtration studies indicated that inhibition of human tissue-type plasminogen activator (t-PA) by rabbit plasma is accompanied by a change in the elution profile of the activator compatible with the formation of an enzyme-inhibitor complex with an apparent molecular weight of 100,000. Injection of human t-PA (1,500 IU/kg body wt) in endotoxin treated animals resulted in very fast inhibition of t-PA and formation of a similar complex. The half-life of circulating PA-inhibitor activity in rabbits was about 7 min as estimated by donor receiver plasma transfusion experiments. Stimulation of cultured human endothelial cells with endotoxin resulted in enhanced rate of accumulation of PA-inhibitor activity in the culture medium (two- to sevenfold increase). In five patients with septicemia, markedly increased levels of PA-inhibitor (14.3 +/- 15.5 U/ml) as compared with control subjects (1.3 +/- 0.7 U/ml) were observed in plasma. A very strong correlation (r = 0.98) was found between inhibition of t-PA and of urokinase in all conditions, suggesting that this fast-acting inhibitor reacts with both plasminogen activators. These data suggest that the appearance of this fast-acting PA-inhibitor is very sensitive to endotoxin stimulation. The marked increase in the level of PA-inhibitor in blood may contribute to the pathogenesis of DIC in septicemia.
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PMID:Generation in plasma of a fast-acting inhibitor of plasminogen activator in response to endotoxin stimulation. 392 Feb 45

When Escherichia coli B6 lipopolysaccharide, 0.2 mg/kg of body weight, was infused into nonpregnant minipigs during a 5-hour period, the animals died after 12 to 16 hours as a result of endotoxic shock. When the same infusion was given to six pregnant minipigs at term, these animals died after only 3 1/2 hours. The decrease in the number of white blood cells, the number of platelets, hematocrit, and clotting factors was not significantly different between the two groups. The acid-base status, however, indicated a much more pronounced metabolic acidosis in the pregnant animals than in the nonpregnant controls. In the pregnant minipigs heart rate, cardiac output, mean arterial pressure, and total peripheral resistance indicated cardiovascular collapse, and the multiple wire, platinum surface electrode revealed a drastic reduction in uterine tissue oxygenation in the pregnant animals. The data support the hypothesis that pregnant animals at term are more susceptible to the harmful effects of lipopolysaccharide. Early death in the pregnant minipigs, however, was not associated with disseminated intravascular coagulation as it is in smaller animals (rat, rabbit, and hamster).
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PMID:Septicemia during pregnancy: a study in different species of experimental animals. 392 Sep 12

Bacterial infection is associated with disseminated intravascular coagulation and fibrin deposition in the microcirculation; the mechanism of these effects in humans is still unclear. We have studied the generation of procoagulant activity (PCA) by cultured human endothelial cells (EC) in response to endotoxin. Cells from umbilical cord veins were grown in Eagle's minimum essential medium with 20% fetal calf serum till confluence. Absence of fibroblasts and macrophages was carefully checked. Endotoxin (Salmonella enteritidis lipopolysaccharide (LPS) W or Escherichia coli 0111:B4 LPS W, 0.01-1.0 micrograms/ml) was added to culture dishes for 4-6 h. PCA of EC was measured by a one-stage clotting assay and/or a two-stage amidolytic assay with the chromogenic substrate S-2222. In the absence of endotoxin, EC generated little, if any PCA (2-5 units/10(5) cells). In contrast, the addition of endotoxin resulted in generation of strong PCA that reached a maximum within 4-6 h (185-241 units/10(5) cells) and was dose-dependent between 1 and 0.01 microgram endotoxin/ml of culture medium. The generation of PCA required RNA and protein synthesis but did not require the presence of serum. No activity was found in the culture medium. The activity was of tissue thromboplastin type, as indicated by biological and immunological criteria. These endotoxin effects were observed in the absence of endothelial damage, as shown by phase-contrast microscopy and lack of 51Cr release. These data could contribute to elucidate the pathogenesis of vascular complications associated with endotoxemia in man.
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PMID:Cultured human endothelial cells generate tissue factor in response to endotoxin. 634 90

The ability of antibody directed against shared antigenic determinants of gram negative organisms to protect against a challenge of diverse gram negative bacterial species remains controversial in the experimental setting. Attention has focused, however, on the use as immunogens of rough mutants of Escherichia coli and Salmonella minnesota, which express a portion of core lipopolysaccharide (LPS) extensively on their cell surface. Core LPS is a structure present on the outer membrane of most, if not all, gram negative bacteria. In this study rabbits were immunized with E. coli J5, a rough mutant of E. coli, to produce anti-E. coli J5 rabbit antiserum (anti-J5 RS). Anti-J5 RS was found to cross react extensively by enzyme-linked immunosorbent assay with various gram negative bacterial whole cell or LPS antigens, compared to normal rabbit serum (NRS). Anti-J5 RS +/- heparin was also compared to NRS +/- heparin pretreatment in a guinea pig model of sepsis utilizing E. coli O111:B4 as the challenge organism. Anti-J5 RS +/- heparin augmented systemic bacterial clearance compared to NRS +/- heparin, but only the combination of anti-J5 RS and heparin enhanced survival 48 hr after bacterial challenge. It was concluded that pretreatment with anti-J5 RS was a necessary, but not sufficient condition for enhanced survival, and that the addition of heparin to anti-J5 RS pretreatment might diminish the otherwise lethal consequences of complement activation and disseminated intravascular coagulation in this model system.
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PMID:The role of heparin in guinea pig gram negative bacterial sepsis. 640

In order to evaluate the possible role of the hepatic macrophage (H-M macrophage) in lipopolysaccharide-induced shock and disseminated intravascular coagulation (DIC), a technique has been developed for the isolation and maintenance in culture of rabbit H-M macrophage. Characterization of the resultant cell population by morphology, nonspecific esterase staining, phagocytosis of latex beads, by presence of Fc and C3b membrane receptors confirms a pure population of M macrophage without outgrowth of other cell types for up to 10 days in culture. The exposure in vitro of the H-M macrophage to LPS (either Salmonella minnesota R595 or Escherichia coli 0111:B4) stimulates a selective increase in activity of several cellular enzyme: LDH, lysozyme, plasminogen activator, and a procoagulant factor, with minimal changes in acid phosphatase and beta-glucuronidase detected. Concomitantly, both in vivo and in vitro treatment with LPS produces an apparent direct cellular toxicity. The combined effect of toxicity and selective stimulation and release of mediators in LPS-stimulated H-M macrophage may play a central role in the endotoxemic shock syndrome.
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PMID:The response of isolated rabbit hepatic macrophages (H-M macrophage) to lipopolysaccharide (LPS). 719 47

Acute respiratory failure is a common complication in patients with disseminated intravascular coagulation associated with sepsis. To elucidate the role of coagulation abnormalities in acute lung injury in sepsis, we investigated the effect of anticoagulants on the pulmonary vascular injury in rat induced by lipopolysaccharide (LPS). When administered intravenously, LPS (5 mg/kg body weight) significantly increased the accumulation of 111indium-labeled neutrophils in lung 30 min after administration. Subsequently, the pulmonary vascular permeability and the serum level of fibrin and fibrinogen degradation products (E) [FDP (E)] increased and remained elevated for several hours. Neither heparin alone, heparin plus antithrombin III, or dansyl-Glu-Gly-Arg-chloromethyl ketone-treated factor Xa, a selective inhibitor of thrombin generation, prevented LPS-induced vascular injury 6 hours after LPS administration, whereas these substances significantly inhibited the increase in serum FDP (E) at that time. LPS-induced pulmonary vascular injury was significantly attenuated in rats with methotrexate-induced leukocytopenia or treated with ONO-5046, a potent granulocyte elastase inhibitor, although ONO-5046 did not inhibit the LPS-induced increase in serum FDP (E). Thus, activated leukocytes play a more important role than coagulation abnormalities in the pathogenesis of LPS-induced pulmonary vascular injury in an experimental rat model of endotoxemia.
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PMID:Endotoxin-induced pulmonary vascular injury is mainly mediated by activated neutrophils in rats. 748 29

1. We have investigated the effect of pretreatment of rats with nitric oxide (NO) synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME) on the E. coli lipopolysaccharide (LPS)-induced changes in the plasma fibrinolytic system, platelet count, fibrinogen level, as well as in gross and microscopic pathophysiological changes indicative of disseminated intravascular coagulation (DIC) in rats. 2. E. coli LPS (6 mg kg-1, i.p.) produced a decrease in the levels of plasma fibrinogen and a drop in the blood platelet count 6 h after administration. The decrease in fibrinogen but not the drop in platelet count was reversed by pretreatment with L-NAME (30 mg kg-1, i.p., 24 h and 15 min before administration of LPS). 3. Pretreatment with L-NAME antagonized the LPS-induced activation of fibrinolysis as measured by changes in the euglobulin clot lysis time (ECLT) and enhanced the LPS-induced rise in the plasma level of plasminogen activator inhibitor (PAI). In animals pretreated with L-NAME there was also a marked reduction in the histological changes indicative of DIC. 4. We propose that L-NAME can act as a protective agent in LPS-induced DIC, and this protection is due to an increased generation of PAI following inhibition of NO synthase.
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PMID:The effect of nitric oxide synthase inhibition on the plasma fibrinolytic system in septic shock in rats. 751 6

We examined the kinetics of tumor necrosis factor (TNF) production induced by Escherichia coli lipopolysaccharide (LPS) in relation to LPS tolerance and endotoxemic lesions of piglets. The plasma of piglets demonstrated cytotoxicity to TNF-sensitive L929 cells between 0.5 and 4 h after inoculation with 200 micrograms kg-1 of LPS. This cytotoxicity was neutralized by anti-bovine TNF serum. These piglets had disseminated intravascular coagulation (DIC) and meningoencephalitis. However, if piglets were first treated with three doses of 40 micrograms kg-1 of LPS, both TNF production and the occurrence of DIC were inhibited when 200 micrograms kg-1 of LPS was inoculated into these piglets. Repetitive inoculation with increasing doses of LPS induced fibrinoid vasculitis, meningoencephalitis and pneumonitis, while hemorrhage was minimal. A very low amount of TNF activity was detected from most of the samples of a piglet after repeated LPS inoculation. These results suggested that severity of the hemorrhagic and thrombotic lesions might relate to the amount of endogenous TNF activity, and that LPS tolerance might relate to inhibition of TNF production.
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PMID:Endogenous tumor necrosis factor (TNF) production and modification of pathological lesions in experimental Escherichia coli endotoxemia of piglets. 760 37


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