Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036690 (sepsis)
 59,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

IL-4 has been found to affect the phenotype and a variety of functions of human monocytes and macrophages and has been discussed as a monocyte activating protein along with other cytokines, such as IL-1 and IL-6. In this study we compared the effects of the cytokines IL-1, IL-6, IL-4, and a combination of IL-1 and IL-6 on the expression of the CD14 antigen, the FcIIIg receptor molecule CD16 and the MHC-class II molecules HLA-DR and HLA-DP. These molecules represent characteristic monocyte surface markers. Furthermore, the CD14 molecule has been described as a surface antigen of high in vivo relevance representing an indirect receptor for LPS. We further analyzed the effect of IL-4 on monocytes and macrophages with respect to their accessory function to initiate T-lymphocyte proliferation. Human peripheral blood monocytes strongly express the antigen CD14 and maintain it as a stable surface molecule during their differentiation to macrophages. Flow cytometry analysis of cultured monocytes demonstrated that cells incubated in the presence of IL-4, but not IL-1 and/or IL-6 revealed a reduced expression of the CD14 antigen in a dose- and time-dependent manner. After 3 days IL-4 treated cells were virtually CD14-negative. At the same time the expression of the CD16 antigen (FcRIIIg) was also strongly reduced, whereas the treatment with IL-4 led to an increased expression of MHC class II antigens such as HLA-DR and HLA-DP. The spontaneous low expression of HLA-DQ antigen on monocytes was not affected by any of the cytokines. Functionally, IL-4 treated CD14-negative monocytes exhibited a more than 2-fold higher activity to stimulate an accessory cell-dependent T cell proliferation. This was found in a mitogenic assay and in MLC when compared to monocytes cultured in the absence of IL-4. These observations provide further evidence that IL-4 is a major modulator of monocyte surface antigen expression. Moreover, IL-4 has an enhancer-effect on monocytes as accessory cells and therefore may be of considerable importance as a regulatory factor during monocyte development to accessory cells. Inasmuch as the CD14 molecule functions as a receptor for LPS-binding protein, our results suggest that IL-4 might also play an important regulatory role in processes initiated by bacterial lipopolysaccharides during inflammation and sepsis.
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PMID:IL-4 decreases the expression of the monocyte differentiation marker CD14, paralleled by an increasing accessory potency. 171 65

Gram-negative bacterial septicemia is a common clinical syndrome resulting, in part, from the activation of phagocytic leukocytes by LPS. By using flow cytometry, we have characterized LPS-induced expression of the beta 2 integrin CD11b/CD18. After exposure to Salmonella minnesota R595 LPS, expression of neutrophil CD11b/CD18 is rapidly upregulated, beginning within 5 min and achieving a peak fluorescence (typically two- to threefold over base line) by 30 min. The increase in CD11b/CD18 expression was similar in kinetics and magnitude to that produced by FMLP, PMA, and human rTNF-alpha. Concentrations of LPS necessary to stimulate a response were as low as 1 ng/ml of R595 LPS; a maximal response was observed between 30 and 100 ng/ml. The upregulation of CD11b/CD18 due to LPS was not interrupted by protein synthesis inhibitors. A group of glucosamine disaccharide lipid A-like molecules: Rhodobacter sphaeroides lipid A, lipid IVA, KDO2IVA, and deacylated LPS were able to block the stimulatory effect of LPS. This inhibition was specific for the actions of LPS as stimulation of polymorphonuclear leukocytes (PMN) by FMLP, human rTNF alpha, PMA, and rewarming were not altered by the disaccharide inhibitors. PMN which were exposed to the specific disaccharide LPS antagonists and then washed, were refractory to stimulation by LPS. The monosaccharide lipid A precursor lipid X also blocked stimulation of neutrophils by LPS, although with a 100-fold reduction in potency. Unlike the disaccharide inhibitors, PMN exposed to lipid X were still responsive to LPS stimulation after washing. The PMN response to LPS was less sensitive in the absence of serum, although upregulation of CD11b/CD18 could still be seen using higher concentrations of LPS. Monoclonal antibody directed against CD14 (clone 3C10), also specifically inhibited LPS induced PMN CD11b/CD18 expression both in the presence and absence of serum. These findings support the hypothesis that LPS stimulates neutrophils by interacting with specific cellular receptors.
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PMID:Lipopolysaccharide-induced stimulation of CD11b/CD18 expression on neutrophils. Evidence of specific receptor-based response and inhibition by lipid A-based antagonists. 171 86

We studied the plasma levels of the acute phase mediator interleukin 6 (IL-6) in 21 severely burned patients (burn injuries ranging from 24% to 75% total body surface area). The posttraumatic course of the IL-6 plasma levels was closely related to the clinical outcome. The nonseptic survivors as well as survivors with suspected sepsis (n = 14) exhibited maximal amounts of IL-6 (251 +/- 32 pg/mL) during the first 3 days post-burn, which subsequently returned to values within the normal range (days 30 to 50; 26 +/- 8 pg/mL). In the nonsurvivors (n = 7) IL-6 concentrations permanently increased (up to 1,921 +/- 356 pg/mL) until death (days 10 to 19) resulting from sepsis with consecutive multiple organ failure. Peripheral blood mononuclear cells (PBMCs) of patients expressed IL-6-specific mRNA in vivo at high levels in contrast to the PBMCs of healthy donors. In addition, the spontaneous and PHA-induced in vitro production of IL-6 by patients' PBMCs was enhanced compared with healthy controls, whereas no significant differences were obtained with bacterial endotoxin (LPS). The findings suggest that interleukin 6 is a potential mediator of lethal sepsis after major thermal trauma.
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PMID:Interleukin 6--a potential mediator of lethal sepsis after major thermal trauma: evidence for increased IL-6 production by peripheral blood mononuclear cells. 174 40

Newborns are susceptible to gram-negative sepsis/septic shock, but there is no established method of its treatment. This study was performed to evaluate the adjuvant effects of dopamine and dobutamine in the indomethacin treatment of newborn endotoxic shock. Endotoxic shock was induced in newborn dogs (2 to 10 days old; 300 to 800 g) by Escherichia coli lipopolysaccharide (LPS; 1.5 mg/kg, intravenously [IV]). Indomethacin (1.5 mg/kg, IV) was injected 5 minutes after LPS injection. Dopamine (5 micrograms/kg/min) or dobutamine (5 micrograms/mg/min) infusion started 5 minutes after LPS injection immediately following indomethacin injection. Hemodynamic parameters were monitored serially for 120 minutes. LPS induced bradycardia and hypotension, decreased the cardiac output and cardiac performance, and increased the total vascular resistance. When dopamine, dobutamine, or indomethacin were used alone, they attenuated the hemodynamic deterioration by LPS. Dopamine infusion following indomethacin administration improved the hemodynamics further, although dobutamine infusion did not. Therefore, we conclude that the adjuvant therapy of dopamine in the indomethacin treatment of newborn endotoxic shock is beneficial.
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PMID:Adjuvant effects of beta-adrenergic drugs on indomethacin treatment of newborn canine endotoxic shock. 177 23

Endotoxemia, complement activation, and the generation of C5a occur in the course of sepsis, trauma, and the adult respiratory distress syndrome, clinical situations in which TNF and IL-1 are thought to play an important role. In the present studies, we examined the effect of picogram concentrations of endotoxin (LPS) on the synthesis of IL-1 beta and TNF alpha by human PBMC exposed to recombinant human C5a (rhuC5a). rhuC5a induced the synthesis of IL-1 beta by PBMC made in response to otherwise substimulatory levels of LPS. In the presence of rhuC5a, LPS concentrations from 10 pg to 1000 pg/ml substantially amplified IL-1 beta synthesis by PBMC compared to LPS alone. Since rhuC5a can induce transcription of IL-1 beta with minimal translation to cytokine protein, these studies support the concept that fM concentrations of LPS can combine with rhuC5a to provide the "second signal" for optimal translation of IL-1 beta mRNA.
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PMID:Picogram concentrations of endotoxin stimulate synthesis of IL-1 beta and TNF alpha by human peripheral blood mononuclear cells exposed to recombinant human C5a. 187 91

We recently developed a murine anti-idiotypic mAb that functioned as a molecular mimic of the O-specific polysaccharide side chain (Ps) of Pseudomonas aeruginosa LPS in vitro, and which induced Ps-specific antibodies in syngeneic BALB/c ByJ mice. In the current studies, we demonstrate that these anti-Id-induced, Ps-specific antibodies fix complement to the bacterial cell surface, and protect neutropenic mice from fatal P. aeruginosa sepsis. The isotypic distribution of the anti-Id-induced antibodies, however, resembles the restricted pattern (IgM and IgG3) seen after administration of purified Ps to mice. The immunogenicity and number of isotypes of Ps-specific antibody produced could be enhanced by conjugating the anti-Id to keyhole limpet hemocyanin. Finally, the anti-Id administered before immunization with purified Ps, primed BALB/c ByJ mice for production of other Ps-specific antibody isotypes (IgG1). These studies show that this anti-Id induces functional anti-Ps antibodies in syngeneic mice, and when used in conjugate form or as a priming agent before Ps immunization, yields an antibody response consistent with "T cell dependence." These immunization strategies may be useful for the induction of polysaccharide-specific antibodies in man.
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PMID:Anti-idiotype-induced, lipopolysaccharide-specific antibody response to Pseudomonas aeruginosa. II. Isotype and functional activity of the anti-idiotype-induced antibodies. 189 98

A major hindrance to the elucidation of the pathogenesis of the adult respiratory distress syndrome (ARDS) is the lack of an animal model consistent with the clinical course in humans. A continuous intravenous infusion of endotoxin (LPS) over a several day period was used to more closely parallel the clinical setting. Male Sprague-Dawley rats infused with LPS via indwelling right atrial catheters become tachypneic, lethargic and anorectic with a steady loss in body weight. Serial blood gas analyses demonstrate an early respiratory alkalosis followed by increasing acidosis and hypoxia. Lungs demonstrate 1) pulmonary leukoaggregation, 2) interstitial and intraalveolar edema, 3) Type I pneumocyte injury, 4) proliferation of Type II pneumocytes, and 5) thickening of the microvascular walls. Differential neutrophil count in bronchoalveolar lavage (BAL) fluid increased from 1% to a peak of 59.1% +/- 3.0% and protein content was elevated. A prolonged infusion of LPS in the rat produces a lung injury which mimics many of the pathophysiologic and histologic features associated with sepsis-induced ARDS in humans.
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PMID:Pulmonary effects of continuous endotoxin infusion in the rat. 190 89

Interferon-gamma (IFN-gamma) has been proposed for use following severe trauma to reverse depressed macrophage (M phi) function and thereby reduce infection, sepsis, and subsequent multiple organ failure syndrome (MOFS). However, an excessive inflammatory response by M phi s and other components of the inflammatory cascade is thought to be central to the underlying pathophysiology of MOFS. Endotoxin (LPS) has been implicated as a principal mediator of sepsis-induced MOFS by stimulating M phi s and leukocytes (WBC). This study addresses the following question: Does IFN-gamma predispose normal rabbits to a pathophysiologic response to LPS infusion? Four groups of New Zealand White rabbits (n = 6, each group) were prepared for measurement of cardiac output, arterial pressure, arterial PO2, and WBC counts over a 6-hr period. Group I (control) was instrumented alone, Group II (LPS alone) was given a subclinical dose of 1.0 micrograms/kg of Escherichia coli LPS iv, Group III (IFN-gamma alone) was given recombinant rabbit IFN-gamma (5.0 micrograms/kg subcutaneous) for 3 days prior to preparation for measurements, and Group IV (IFN-gamma + LPS) received 3 days of IFN-gamma followed by LPS. One hour prior to sacrifice 5.0 microCi of 125I-albumin was given and bronchoalveolar lavage was performed at death to determine the lavage/plasma 125I ratio as an index of pulmonary permeability. The results indicate that IFN + LPS animals had significant decreases in cardiac output, PO2, and WBC counts, and increased lavage/plasma ratio of 125I-albumin when compared to all other groups (P less than 0.05 by ANOVA, t test). Neither LPS alone nor IFN-gamma alone had a significant effect on measured variables.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Interferon gamma increases sensitivity to endotoxin. 190 23

The regulation of type 1 plasminogen activator inhibitor (PAI-1) gene expression was studied in vivo employing a murine model system. Nuclease protection analysis revealed relatively high concentrations of PAI-1 mRNA in the aorta, adipose tissue, heart, and lungs of untreated CB6 (BalbC X C57B16) mice. Treatment of CB6 mice with LPS, TNF-alpha, or transforming growth factor-beta (TGF-beta) increased the steady-state levels of PAI-1 mRNA within 3 h in all tissues examined. However, the greatest responses to TGF-beta were observed in adipose tissue and the kidney, while LPS and TNF-alpha strongly stimulated PAI-1 gene expression in the liver, kidney, lung, and adrenals. In C3H/HeJ mice, which exhibit defective TNF-alpha release in response to LPS, the response of the PAI-1 gene to LPS was severely attenuated. However, injection of these mice with TNF-alpha increased PAI-1 mRNA in a tissue-specific pattern strikingly similar to that observed in LPS-treated CB6 mice. These results demonstrate that the PAI-1 gene is regulated in a complex and tissue-specific manner in vivo, and suggest a role for TNF-alpha in the response of the PAI-1 gene to sepsis.
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PMID:Regulation of murine type 1 plasminogen activator inhibitor gene expression in vivo. Tissue specificity and induction by lipopolysaccharide, tumor necrosis factor-alpha, and transforming growth factor-beta. 191 85

The production by monocytes of interleukin-1 alpha (IL-1 alpha), interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF alpha) in intensive care unit (ICU) patients with sepsis syndrome (n = 23) or noninfectious shock (n = 6) is reported. Plasma cytokines, cell-associated cytokines within freshly isolated monocytes and LPS-induced in vitro cytokine production were assessed at admission and at regular intervals during ICU stay. TNF alpha and IL-6 were the most frequently detected circulating cytokines. Despite the fact that IL-1 alpha is the main cytokine found within monocytes upon in vitro activation of cells from healthy individuals, it was very rarely detected within freshly isolated monocytes from septic patients, and levels of cell-associated IL-1 beta were lower than those of TNF alpha. Cell-associated IL-1 beta and TNF alpha were not correlated with corresponding levels in plasma. Upon LPS stimulation, we observed a profound decrease of in vitro IL-1 alpha production by monocytes in all patients, and of IL-1 beta, IL-6, and TNF alpha in septic patients. This reduced LPS-induced production of cytokines was most pronounced in patients with gram-negative infections. Finally, monocytes from survival patients, but not from nonsurvival ones recovered their capacity to produce normal amounts of cytokines upon LPS stimulation. In conclusion, our data indicate an in vivo activation of circulating monocytes during sepsis as well as in noninfectious shock and suggest that complex regulatory mechanisms can downregulate the production of cytokines by monocytes during severe infections.
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PMID:Dysregulation of in vitro cytokine production by monocytes during sepsis. 193 59


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