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Query: UMLS:C0036690 (sepsis)
 59,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A total of 41 Neissera meningitidis isolates were analyzed for capsular polysaccharide (CP) and lipopolysaccharide (LPS) release and filtrability. Twenty-two of these isolates were serogroup B from blood or cerebrospinal fluid of patients, five were group B isolates from healthy throat carriers, and 14 were nongroupable (acapsular) meningococcal isolates from healthy carriers. Filtration of liquid whole-cell cultures through cellulose acetate-nitrate filters resulted in distinctly lower LPS filtrate activity for acapsular than for capsular meningococci (p less than 0.001). On the other hand, when polysulfone membrane filtration was performed, filtrates from acapsular and capsular meningococci contained LPS in similar amounts. These results indicate that LPS-containing particles released from acapsular isolates are larger or more aggregated than corresponding CP- and LPS-containing particles released from capsular isolates. The LPS released from acapsular isolates apparently are more efficiently retained by adsorption to cellulose acetate-nitrate. From the capsular isolates comparatively more CP than LPS appeared to be released, as related to cell-bound amounts. The total amounts of CP and released, filtrable LPS through cellulose acetate-nitrate filters were both relatively low and had similar values for capsular carrier meningococci and systemic isolates from mild meningococcal disease. The amount of CP released and passing this type of membrane was significantly higher for systemic isolates from severe septicemia than from mild meningococcal disease (p = 0.03).
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PMID:Neisseria meningitidis group B capsular polysaccharide. Bacterial content and release in relation to categories of infection and filtrability of released endotoxin. 211 12

Respiratory tract infections are major causes of excessive morbidity and mortality in hospitalized patients. Persons with systemic sepsis have an especially high risk of acquiring these infections, which indicates that their lung antibacterial defenses are compromised. To evaluate the effects of sepsis on pulmonary antibacterial defenses, we injected either saline or 5 mg/kg of Escherichia coli lipopolysaccharide intravenously into Sprague-Dawley rats. Two hours later, the animals were challenged by aerosol inhalation with either Staphylococcus aureus or Pseudomonas aeruginosa. It is known that phagocytic defenses against aerosolized S. aureus challenges are provided solely by the alveolar macrophage; in normal animals challenged with P. aeruginosa, however, an intrapulmonary inflammatory response is elicited. Animals pretreated with endotoxin showed a significant decrease in pulmonary bactericidal activity against S. aureus with 31 +/- 3% bacteria remaining viable at 4 hr compared with 20 +/- 2% in the controls, which indicates a defect in alveolar macrophage antimicrobial activity. After P. aeruginosa challenge, saline-injected control animals developed a marked intrapulmonary inflammatory response and killed greater than 85% of their initial inoculum by 4 hr. By contrast, endotoxin-treated animals failed to recruit neutrophils into the alveoli in response to P. aeruginosa, resulting in a proliferation of this pathogen within the lung (212 +/- 6% bacteria remaining viable at 4 hr). Endotoxin is known to be a potent stimulus for the production of tumor necrosis factor (TNF) by the host. TNF is a potent inflammatory mediator and promotes neutrophil adhesion to the vascular endothelium. In these experiments, serum TNF peaked at 28,390 +/- 7,766 Units/ml. 90 min after intravenous endotoxin. Histopathology of the lungs in these animals showed considerable sequestration of the neutrophils within the pulmonary vasculature. These data show that systemic endotoxin significantly impairs lung host defenses against intrapulmonary bacterial challenges and suggest that TNF-mediated events may play a central role.
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PMID:Endotoxin-induced suppression of lung host defenses. 212 Mar 77

International Antigen Typing Schema (IATS) serotypes 1, 2, 5, 6, 8 and 11 comprise approximately 80% of Pseudomonas aeruginosa strains isolated from blood, wounds and respiratory specimens. Five human immunoglobulin M (IgM) monoclonal antibodies (MAbs) reactive with lipopolysaccharide O antigens of these IATS serotypes were studied in an opsonophagocytic assay. The assay employed human polymorphonuclear leukocytes, 2% guinea pig serum as the complement source and MAb. Each MAb promoted killing of inoculum of the homologous LPS serotype. The opsonic activity of each MAb was complement-dependent. In a murine model of Pseudomonas burn wound sepsis the LD50 of five strains of P. aeruginosa was increased greater than or equal to 22-fold by MAb-treatment (1.0 mg/kg). The mean effective dose of the five MAbs in mice challenged with approximately 10 LD50 of the homologous LPS serotype ranged from less than 0.01 mg/kg to 1.00 mg/kg.
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PMID:Opsonic and protective activity of five human IgM monoclonal antibodies reactive with lipopolysaccharide antigen of Pseudomonas aeruginosa. 212 68

Antibody responses of mice immunized with type III pneumococcal polysaccharide were examined with and without treatment with nontoxic lipopolysaccharide from Rhodopseudomonas sphaeroides (Rs-LPS). The results obtained were similar to those described previously for mice treated with monophosphoryl lipid A (MPL) except that lower amounts of Rs-LPS were needed. Both were without effect when given at the time of immunization with type III pneumococcal polysaccharide but elicited significant enhancement when given 2 to 3 days later. Such enhancement was T cell dependent and not due to polyclonal activation of immunoglobulin M synthesis by B cells. Treatment with either Rs-LPS or MPL abolished the expression but not induction of low-dose paralysis, a form of immunological unresponsiveness known to be mediated by suppressor T cells (Ts). The in vitro treatment of cell suspensions containing Ts with extremely small amounts of Rs-LPS or MPI completely eliminated the capacity of such cells to transfer suppression to other mice. These findings indicate that the immunomodulatory effects of both MPL and Rs-LPS are mainly the result of eliminating the inhibitors effects of Ts; this permits the positive effects of amplifier T cells to be more fully expressed, thereby resulting in an increased antibody response. The significance of these and other findings to the use of Rs-LPS as a pharmacotherapeutic agent for gram-negative bacterial sepsis is discussed.
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PMID:Inactivation of suppressor T cell activity by the nontoxic lipopolysaccharide of Rhodopseudomonas sphaeroides. 214 52

The objective of this study was to analyze monokine production by peripheral blood mononuclear cells from patients with alcoholic cirrhosis. The capacity of peripheral blood mononuclear cells and purified monocytes from these patients to produce tumor necrosis factor alpha, interleukin 1 beta, and interleukin 6 was investigated. Spontaneous production of tumor necrosis factor alpha, interleukin 6 and interleukin 1 beta was similar in cirrhotic and healthy subjects, but serum levels of interleukin 6 (less than 2 U/ml vs. 9.5 +/- 3 U/ml) and tumor necrosis factor alpha (3.1 +/- 1.2 pg/ml vs. 12.0 +/- 1.2 pg/ml) were significantly higher in cirrhotic patients. However, peripheral blood mononuclear cells or purified monocytes from patients with alcoholic liver cirrhosis, stimulated in vitro with Escherichia coli lipopolysaccharide, displayed a marked increase of tumor necrosis factor alpha, interleukin 1 beta and interleukin 6 secretions compared with healthy controls. A striking feature of this overproduction was its reversibility as assessed by allowing cells to rest in vitro without lipopolysaccharide for 1 to 7 days before stimulation. In such conditions, tumor necrosis factor alpha and interleukin 6 secretions declined to levels present in healthy subjects in whom production remained stable, whereas interleukin 1 beta secretion markedly decreased in both groups to the point where no difference could be seen. This reversible oversecretion of cytokines after lipopolysaccharide stimulation, along with the lack of abnormality of spontaneous cytokine secretion, suggests that monocytes in these patients may have undergone an in vivo activation process analogous to a priming phenomenon. The in vitro activation with lipopolysaccharide may represent the correlate of in vivo endotoxemia observed during acute events such as sepsis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Excessive in vitro bacterial lipopolysaccharide-induced production of monokines in cirrhosis. 218 15

Multiple extrapulmonary organ system failures increase mortality, permeability edema, and alveolar inflammation during gram-negative sepsis because of abnormal regulation of host inflammatory responses. We tested the hypothesis that acute hepatocytic injury induced by the selective hepatotoxin, D-galactosamine (GalN), augments mortality and amplifies pulmonary microvascular permeability to albumin and neutrophilic influx after administering Escherichia coli lipopolysaccharide (LPS) 24 h later by impairing the metabolism of endogenously synthesized products of arachidonic acid. We determined the lung extravascular leak of 125I-human serum albumin measured at multiple time points after LPS and enumerated polymorphonuclear leukocytes (PMNs) in bronchoalveolar lavage fluid (BALF). Because the liver is important in prostaglandin (PG) and leukotriene (LT) metabolism, we measured plasma concentrations of 6-keto-PGF1 alpha and thromboxane B2 (TxB2) in addition to paired plasma BALF concentrations of LTB4 and BALF LTC4 60 min and 24 h after LPS. We further assessed the protective effects of a single 20-mg/kg injection given intraperitoneally (i.p.) of the LTA4 synthetase inhibitor, diethylcarbamazine (DEC). After 400 mg/kg GalN, LPS at 2.5 or 1.25 mg/kg i.p. increased mortality (p less than 0.001), albumin leak 60 and 90 min after LPS (p less than 0.05), plasma 6-keto-PGF1 alpha, TxB2, and LTB4 levels and BALF LTC4 within 60 min (p less than 0.05). LTB4 and LTC4 levels in BALF 24 h later were similarly increased (p less than 0.05) as were bronchoalveolar PMNs (p less than 0.001). DEC improved mortality and albumin leak (p less than 0.001), reduced lung influx of PMNs and peripheral leukocytosis (p less than 0.05), attenuated plasma LTB4 and BALF LTC4 levels 60 min after LPS (p less than 0.05), and decreased BALF LTB4 and LTC4 at 24 h (p less than 0.05), but was associated with higher plasma 6-keto-PGF1 alpha and TxB2 values at 60 min. Changes in eicosanoid levels and modulation of responses by DEC in this model suggest that impaired metabolism of endogenously synthesized leukotriences by the damaged liver underlies these phenomena. We conclude that this mechanism may enhance septic lung injury during acute liver dysfunction.
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PMID:Effects of D-galactosamine-induced acute liver injury on mortality and pulmonary responses to Escherichia coli lipopolysaccharide. Modulation by arachidonic acid metabolites. 218 85

Tumor necrosis factor (TNF) released by lipopolysaccharide (LPS)-stimulated mononuclear phagocytes is a critical mediator of sepsis. We examined the capacities of rough mutant Salmonella typhimurium LPS (Rc) and LPS partial structures lipid A, monophosphoryl lipid A (MPLA), lipid IVA, and lipid X to induce production of TNF in whole blood. Rc LPS (0.0001-10 ng/ml) produced a dose-dependent release of TNF as determined by cytotoxicity of actinomycin D-sensitized L929 murine fibroblasts. Lipid A, MPLA, lipid IVA, and lipid X exhibited decreasing capacities to stimulate production of TNF in whole blood, respectively. Fractional deacylation of LPS by incubation with acyloxyacyl hydrolase isolated from human leukocytes produced a reduction in the capacity of LPS to induce TNF release in whole blood. Maximal enzymatic deacylation reduced activity of LPS by greater than 100-fold. Coincubation with lipid IVA inhibited TNF release induced by Rc LPS or lipid A, but not by phorbol ester. In contrast, MPLA, lipid X, and deacylated LPS failed to inhibit LPS-stimulated release of TNF. Corresponding to the inhibition of the release of TNF protein, lipid IVA also inhibited the accumulation of TNF mRNA in LPS-stimulated mononuclear cells. These results suggest that lipid IVA may act as a competitive antagonist of LPS, perhaps at the receptor level.
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PMID:Lipid IVA inhibits synthesis and release of tumor necrosis factor induced by lipopolysaccharide in human whole blood ex vivo. 219 1

Tumor necrosis factor, a mononuclear phagocyte-derived peptide produced in response to lipopolysaccharide, has been shown to mediate certain aspects of septic shock and multiple organ failure resulting from gram-negative septicemia. In the present investigation, pretreatment of animals with pentoxifylline inhibited lipopolysaccharide-induced serum tumor necrosis factor in a dose-dependent fashion. Pentoxifylline prevented the sequestration of neutrophils seen in animals given intravenous lipopolysaccharide. Furthermore, pentoxifylline protected animals from the lethal effects of an intravenous challenge with lipopolysaccharide. These data indicate that pentoxifylline inhibits lipopolysaccharide-induced tumor necrosis factor and may be an effective agent in mitigating the lethal consequences of sepsis and other disease processes mediated by this cytokine.
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PMID:Pentoxifylline inhibits lipopolysaccharide-induced serum tumor necrosis factor and mortality. 223 23

A prospective nationwide surveillance of invasive Haemophilus influenzae type b disease among adults (greater than or equal to 16 years old) was conducted in Finland during 1985 through 1988. Thirty-one cases were identified (annual incidence, 0.22/100,000). Of these infections, 71% occurred in patients with severe underlying conditions. The overall case fatality rate was 26%. Septicemia (13 patients) and pneumonia (seven patients) were the most common clinical manifestations of H influenzae type b infection; the others were epiglottitis (six patients), meningitis (three patients), and arthritis (two patients). Epiglottitis occurred in significantly younger patients, all of whom were women and four of whom were previously healthy. Subtyping of the H influenzae type b isolates according to the major outer membrane protein subtype, biotype, and lipopolysaccharide serotype showed that patterns that were uncommon (14%) among children were more common (27%) in the adults.
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PMID:Spectrum of invasive Haemophilus influenzae type b disease in adults. 224 74

Rabbits reconvalescent from experimental septicemia due to serologically defined strains of Serratia marcescens were examined for the diversity of their humoral antibody response with traditional serological procedures and the Western blot (immunoblotting) technique. Trichloracetic acid (TCA)-whole cell extracts of the homologous and heterologous O-antigen reference strains served as the antigen for the latter procedure. Reconvalescent rabbit sera contained antibodies against the homologous lipopolysaccharide (LPS) moiety (molecular weight (MW) range = 45-31 kilodaltons (= k] and antibodies against numerous heat-modifiable, cross-reactive proteins, in particular 7 proteins characterized by MWs of 117 k, 95 k, 91 k, 71 k, 68 k, 38 k, and 33 k in TCA-whole cell extracts from the homologous as well as from 11 heterologous S. marcescens O-antigen reference strains. Rabbits, which had been actively immunized with TCA-whole cell extracts from representative S. marcescens strains, mounted a humoral antibody response remarkably similar to that of rabbits which had recovered from septicemia, except that the sera from the actively immunized animals interacted somewhat more strongly with an additional cross-reactive protein (MW = 47 k). Conversely, conventional anti-O and anti-H rabbit immune sera revealed antibodies directed predominantly against the homologous LPS moiety (MW range = greater than or equal to 200 k - less than or equal to 15 k). It was concluded that numerous proteinaceous cellular constituents of S. marcescens accounted for immunoblot cross-reactivity.
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PMID:Humoral antibody response of rabbits against experimental Serratia marcescens septicemia. 224 83


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