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)

In vivo determination of protein synthesis in immune cells reflects metabolic activity and immunological activation. An intravenous injection of endotoxin to healthy volunteers was used as a human sepsis model, and in vivo protein synthesis of T lymphocytes and leucocytes was measured. The results were related to plasma concentrations of selected cytokines, peripheral cell counts and subpopulations of immune cells. The subjects (n = 8 + 8) were randomized to an endotoxin (4 ng/kg) or a saline group. In vivo protein synthesis was determined twice: before and 1-2.5 h after the endotoxin/saline injection. Protein synthesis decreased in isolated T lymphocytes, but increased in leucocytes. Plasma levels of TNF-alpha, IL-8, IL-6, IL-1 ra and IL-10 were elevated, whereas IL-2 and IFN-gamma, produced predominantly by T lymphocytes, did not change in response to endotoxin. Neutrophils increased, whereas lymphocytes and monocytes decreased 2.5 h after the endotoxin injection. Flow cytometry revealed a drop in total CD3+ T lymphocytes and CD56+ natural killer cells, accompanied by an increase in CD15+ granulocytes. In summary, in vivo protein synthesis decreased in T lymphocytes, while the total leucocyte population showed a concomitant increase immediately after the endotoxin challenge. The changes in protein synthesis were accompanied by alterations in immune cell subpopulations and in plasma cytokine levels.
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PMID:Response of in vivo protein synthesis in T lymphocytes and leucocytes to an endotoxin challenge in healthy volunteers. 1239 Mar 14

Thermal injury to 40% or more of the total body surface area poses a significant risk for the development of opportunistic infections that increase complications and mortality. Altered cytokine induction profiles, including suppression of the Th1 cytokines IFN-gamma and IL-12 and elevations in the anti-inflammatory cytokine IL-10, are believed to contribute to burn-associated immunosuppression and the development of sepsis. The specific changes that lead to altered cytokine production following major burns are not known. We examined the effects of burn injuries to 40% of the mouse body surface on IFN-gamma induction in the major IFN-gamma-producing cell types of the spleen. Additionally, effects on key IFN-gamma-regulatory cytokines were examined after bacterial challenge. We report that in vivo induction of IFN-gamma in natural killer lymphocytes is suppressed in burned mice. Splenic IFN-gamma was suppressed at both the mRNA and protein levels. Early suppression was associated with impairments in both the macrophage/dendritic cell and lymphocyte populations, whereas persistent suppression was associated with impaired lymphocyte function and decreased responsiveness to IFN-gamma-inducing factors. IFN-gamma production could be restored by neutralization of the upregulated cytokine IL-10. Induction of the IFN-gamma-inducers IL-15, IL-12, and IL-2 was also impaired after burn injury, whereas IL-18 levels remained unaffected. Exogenous application of these suppressed cytokines to isolated splenocytes did not restore IFN-gamma to sham levels, indicating a loss of responsiveness to these factors. Expression of the IL-2, IL-12, and IL-15 receptors was suppressed after thermal injury. We conclude that burn-associated suppression of IFN-gamma is due to deficient production of inducing factors and their receptors, leading to severe impairments in cellular IFN-gamma induction pathways.
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PMID:Interferon-gamma production is suppressed in thermally injured mice: decreased production of regulatory cytokines and corresponding receptors. 1239 75

Group B streptococcus (GBS) is the leading cause of sepsis in neonates. Nitric oxide (NO) release plays a role in the hypotension that characterizes septic shock. It has been shown that GBS beta-hemolysin/cytolysin (beta-h/c) stimulates the transcription of inducible NO synthase (iNOS) in murine macrophages via intracellular pathways similar to those that mediate lipopolysaccharide-induced iNOS activation. Here, it is demonstrated that the GBS cell wall and beta-h/c act synergistically to induce iNOS in interferon (IFN)-gamma-primed [corrected] RAW 264.7 murine macrophages. In nonprimed macrophages, combined activation by the GBS cell wall plus beta-h/c is necessary to induce an NO response, which indicates that both virulence factors cooperate to substitute for the priming signal typically provided by IFN-gamma [corrected].
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PMID:Synergistic action of nitric oxide release from murine macrophages caused by group B streptococcal cell wall and beta-hemolysin/cytolysin. 1240 73

Reduction of neutrophil apoptosis represents a major cause for granulocytosis and increases the destructive potential of theses cells during systemic inflammatory response syndrome (SIRS) and sepsis. In this light, the role of protein kinases for the regulation of altered neutrophil apoptosis under infectious conditions was investigated. Neutrophils, obtained from patients with severe sepsis (n = 18), were incubated ex vivowith either LPS (1 microg/mL) or interferon-gamma (IFN-gamma; 10 ng/mL) for 16 h. Apoptosis was determined by propidium iodine (PI) staining of DNA fragments and was compared with the rate of spontaneous apoptosis. Tyrosine kinases were inhibited by herbimycin (1 microM), the mitogen-activated protein (MAP) kinase ERK was inhibited with PD98059 (50 microM), and p38 MAP kinase was inhibited with SB203580 (5 microM). Herbimycin reconstituted LPS-reduced apoptosis in neutrophils from controls (39.9 +/- 3.8%) and patients (20.8 +/- 2.8%) to levels seen in spontaneous apoptosis (70.9 +/- 2.8% and 40.7 +/- 3.7%, respectively). Inhibition of the ERK kinase yielded similar results, whereas SB203580 had no effect on LPS-reduced apoptosis. However, inhibition of p38 partially reconstituted IFN-gamma-reduced apoptosis (51.3 +/- 7.7% and 25.6 +/- 5.8%) and increased spontaneous apoptosis (82.4 +/- 3.3% and 42.0 +/- 5.8%) in controls and patients, respectively. Western blot analysis revealed phosphorylation of both MAP kinases by LPS, but not by IFN-gamma. Inhibition of MAP kinases did not augment neutrophil apoptosis in patients to the level seen in controls, indicating that other mechanisms must be involved in the regulation of neutrophil apoptosis. Although the ERK kinase regulates LPS-induced reduction of apoptosis, the p38 MAP kinase might be involved in IFN-gamma signaling and the feedback regulation of neutrophil apoptosis.
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PMID:Activation of mitogen-activated protein kinases during granulocyte apoptosis in patients with severe sepsis. 1241 17

The rate of oxygen consumption by certain tissues is impaired when mice or rats are injected with lipopolysaccharide. A similar change in the rate of oxygen consumption is observed when Caco-2 human enterocyte-like cells are incubated in vitro with cytomix, a cocktail of cytokines containing tumor necrosis factor, IL-1beta, and IFN-gamma. The decrease in the rate of oxygen consumption is not due to a change in oxygen delivery (e.g. on the basis of diminished microvascular perfusion), but rather to an acquired intrinsic defect in cellular respiration, a phenomenon that we have termed 'cytopathic hypoxia'. A number of different biochemical mechanisms have been postulated to account for cytopathic hypoxia in sepsis, including reversible inhibition of cytochrome a,a3 by nitric oxide, and irreversible inhibition of one or more mitochondrial respiratory complexes by peroxynitrite. Recently, however, our laboratory has obtained data to suggest that the most important mechanism underlying the development of cytopathic hypoxia is depletion of cellular stores of nicotinamide adenine dinucleotide (NAD+/NADH) as a result of activation of the enzyme, poly(ADP-ribose) polymerase-1. If cytopathic hypoxia is important in the pathophysiology of established sepsis and multiorgan dysfunction syndrome, then efforts in the future will need to focus on pharmacological interventions designed to preserve normal mitochondrial function and energy production in sepsis.
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PMID:Bench-to-bedside review: Cytopathic hypoxia. 1249 70

Group B streptococci (GBS) are an important cause of neonatal sepsis, pneumonia and meningitis. In some newborns, GBS sepsis may have a severe course, including septic shock with high mortality rate, whereas other newborns are colonized with GBS on their surfaces without any clinical signs of bacterial infections. Interferon (IFN)-gamma is produced in neonatal GBS sepsis, and transforming growth factor (TGF)-beta is also found in the uterus. The involvement of IFN-gamma and TGF-beta in the earliest phase of infection might be a determinant of susceptibility and/or progression of infection in vivo. The aim of this study was to assess the effect of IFN-gamma and TGF-beta on adherence and intracellular viability in ECV304 cells of GBS serotype III isolated from cerebrospinal fluid (CSF) and vagina (strains 90356 and 80340, respectively). Interaction of GBS-ECV304 cells showed that the CSF isolate exhibited a more efficient adherence mechanism than the vagina isolate (P<0.001). Intracellular viability was observed for the CSF 90356 isolate within 2 h incubation. Results suggest the expression of additional bacterial virulence factors that favor some GBS type III strains to cause invasive disease. Detection of genotypic virulence marker (162-kb) in the CSF 90356 isolate by PFGE emphasizes the high risk of invasive infection by some GBS-III strains. Treatment of ECV304 cells with IFN-gamma and/or TGF-beta increased adherence of both GBS strains (P<0.001). Intracellular survival of the CSF 90356 isolate was observed after 24 h incubation following treatment of ECV304 cells with IFN-gamma and TGF-beta. Our data suggest that both IFN-gamma and TGF-beta may favor virulence of GBS strains. Variation of IFN-gamma and TGF-beta producing capacity of host cells of different individuals may influence development of invasive disease by GBS-III.
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PMID:The effects of interferon-gamma and transforming growth factor-beta on adherence and survival of group B Streptococcus type III strains in ECV304 cells. 1257 48

An increased extracellular production of free radicals with bactericidal activity does not improve the efficacy of intracellular digestion of Staphylococci. The amount of intracellular oxygen reactive species generated by the neutrophils from patients with an infectious condition has been found considerably decreased as compared to healthy donors. On the other hand, the excess of secretion of free radicals into the extracellular space leads inevitably to the adaptive increase of antioxidant enzymes and, as a result, to an increase in the total antioxidant capacity of the blood plasma. Indeed, patients with septicemia at its highest peak (at the moment of hospitalization) showed a significant increase (more than twice) in the parameters of catalase and superoxide dismutase activity; the antioxidant capacity of the plasma was elevated as well. The patients of the other two groups in our study (with a localized infection) did not show any statistically significant rise in these parameters. On the second day after the initiation of an intensive treatment the activity of the enzymes and the total antioxidant capacity of the plasma dropped sharply below the normal level. Therefore, the staphylococcus infection, especially its generalized from, is characterized by an increased extracellular secretion of radicals together with a decreased generation of intracellular radicals. On one hand this leads to the failure of the intracellular killing, on the other--to the inflammatory free radical-mediated damage of the host cells and tissues. Cytokines, such as interleukins and interferons, can regulate the free radical-mediated processes during the staphylococcus infections. The effect of the two recombinant cytokines (IL-1 beta, IFN-gamma) on the character of free radical production and intracellular killing of Staphylococci by neutrophils isolated from the blood of patients and healthy donors has been studied. The analysis of the effect of cytokines on the radical production by phagocytes revealed a redistribution of the extracellular and intracellular fractions of free radicals rather than a general increase of the oxygen active metabolite production. As expected, the increment in the number of intracellular radicals improved significantly the process of phagocytosis.
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PMID:Effect of cytokines on the level of free radicals in the blood of patients with systemic and local staphylococcus infection. 1267 35

We have previously shown that systemic infusion of the bacterial toxins Staphylococcal enterotoxin B (SEB) and endotoxin (LPS) induces hepatic dysfunction as measured by decreased biliary indocyanine green (ICG) excretion. In this study, we compare the effects of these bacterial toxins after infusion into the portal and systemic circulation and directly measure biliary bile acid excretion as a measure of cholestasis. We hypothesized that bacterial toxins infused into the portal vein would induce greater hepatic dysfunction than toxins infused into the systemic circulation. Using a chronically catheterized rat model, biliary bile acid excretion was directly measured after infusion of LPS at 10 and 100 microg/kg with and without 50 microg/kg SEB into the portal vein (IPV) or inferior vena cava (IV) at baseline, and at 6 and 24 h. We found that when LPS was infused alone, only IPV administration caused a significant decrease in bile acid excretion at 6 h. There was no change in bile acid excretion after IV administration of LPS. In contrast, when the combination of LPS and SEB was infused, both IV and IPV administration significantly decreased bile acid excretion at 6 and 24 h. At 6 h post-LPS and -SEB administration, the decrease in bile acid excretion was significantly greater after IPV than IV administration. There was no site-specific difference in IFN-gamma release after infusion of toxins. However, peak TNFalpha release was decreased in IPV-infused rats [10 microg/kg (P < 0.05) or 100 microg/kg (P = ns) LPS with SEB] compared with the same doses in IV-infused rats. These data question the role of systemic TNF-alpha and IFN-gamma in regulating hepatic dysfunction and suggest a differential functional response of the liver to systemic and gut-derived septic events. This study also further explains the frequent development of liver dysfunction in patients with sepsis, multisystem organ failure, and other diseases with altered intestinal permeability.
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PMID:Differential induction of hepatic dysfunction after intraportal and intravenous challenge with endotoxin and Staphylococcal enterotoxin B. 1268 47

Studies indicate that administration of the adrenal steroid dehydroepiandrosterone (DHEA) after trauma-hemorrhage in male mice improved cellular immune functions and reduced mortality rates from subsequent sepsis. There is evidence, however, that DHEA is converted to estrogens in males and that estrogens are immunoprotective after trauma-hemorrhage (TH). In contrast, DHEA in females can be converted to testosterone that has deleterious effects on immune functions. The aim of our study, therefore, was to determine whether administration of DHEA in proestrus females after TH would deteriorate immune responses. Proestrus female C3H/HeN mice (age 7-8 wk) were subjected to laparotomy (i.e., soft tissue trauma induced) and hemorrhagic shock (35 +/- 5 mmHg for 90 min) or sham operation. The mice then received DHEA (100 micro/25 g body wt) or vehicle subcutaneously followed by fluid resuscitation (4x the shed blood volume). Plasma IL-6, splenocyte proliferation, splenocyte IL-2, IL-3, IFN-gamma, IL-10 release, and splenic Mphi IL-1beta, IL-6, IL-10, and IL-12 release were determined 24 h after TH. Plasma IL-6 levels were significantly increased in vehicle-treated females, and DHEA administration markedly attenuated this response. In vehicle-treated females, splenocyte proliferation, IL-2, IL-3, and IFN-gamma release, and splenic Mphi IL-1 beta, IL-6, and IL-12 release were maintained or slightly enhanced after TH. In DHEA-treated females, however, these immune functional parameters were either unaltered compared with vehicle-treated animals or even further enhanced, but surprisingly were not depressed. Moreover, DHEA reduced splenocyte and splenic M phi anti-inflammatory cytokine (i.e., IL-10) production after TH compared with vehicle-treated females. Because DHEA further enhances the immune responsiveness in proestrus females after TH, this hormone might be a useful adjunct even in females for further enhancing immune responses and decreasing the mortality rate after trauma and severe blood loss.
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PMID:Immunomodulatory effects of dehydroepiandrosterone in proestrus female mice after trauma-hemorrhage. 1269 47

In sepsis, both necrotic and apoptotic cell death can occur. Apoptotic cells induce anergy that could impair the host response, whereas necrotic cells cause immune activation that might result in enhanced antimicrobial defenses. We determined whether adoptive transfer of apoptotic or necrotic cells impacted survival in a clinically relevant sepsis model. We also evaluated the effects of adoptive transfer of apoptotic or necrotic cells on the prototypical TH1 and TH2 cytokines IFN-gamma and IL-4, respectively. C57BL6/J mice had adoptive transfer of apoptotic (irradiated) or necrotic (freeze thaw) splenocytes. Controls received saline. Apoptotic cells greatly increased mortality, whereas necrotic splenocytes markedly improved survival, P < or = 0.05. The contrasting effects that apoptotic or necrotic cells exerted on survival were mirrored by opposite effects on splenocyte IFN-gamma production with greatly decreased and increased production, respectively. Importantly, either administration of anti-IFN-gamma antibodies or use of IFN-gamma knockout mice prevented the survival benefit occurring with necrotic cells. This study demonstrates that the type of cell death impacts survival in a clinically relevant model and identifies a mechanism for the immune suppression that is a hallmark of sepsis. Necrotic cells (and likely apoptotic cells) exert their effects via modulation of IFN-gamma
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PMID:Adoptive transfer of apoptotic splenocytes worsens survival, whereas adoptive transfer of necrotic splenocytes improves survival in sepsis. 1273 77


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