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

Tumor necrosis factor alpha (TNF alpha), a primary mediator of systemic responses to sepsis and infection, can be injurious to the organism when present in excessive quantities. Here we report that two types of naturally occurring soluble TNF receptors (sTNFR-I and sTNFR-II) circulate in human experimental endotoxemia and in critically ill patients and demonstrate that they neutralize TNF alpha-induced cytotoxicity and immunoreactivity in vitro. Utilizing immunoassays that discriminate between total sTNFR-I and sTNFR-I not bound to TNF alpha, we show that sTNFR-I-TNF alpha complexes may circulate even in the absence of detectable free TNF alpha. To investigate the therapeutic possibilities of sTNFR-I, recombinant protein was administered to nonhuman primates with lethal bacteremia and found to attenuate hemodynamic collapse and cytokine induction. We conclude that soluble receptors for TNF alpha are inducible in inflammation and circulate at levels sufficient to block the in vitro cytotoxicity associated with TNF alpha levels observed in nonlethal infection. Administration of sTNFR-I can prevent the adverse pathologic sequelae caused by the exaggerated TNF alpha production observed in lethal sepsis.
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PMID:Tumor necrosis factor soluble receptors circulate during experimental and clinical inflammation and can protect against excessive tumor necrosis factor alpha in vitro and in vivo. 131 75

Tumor necrosis factor alpha (TNF) has been described as a primary mediator of the pathophysiology associated with bacterial sepsis/endotoxemia. We tested the efficacy and possible mechanisms of protection of a monoclonal antibody against TNF (TNF Mab) in a low mortality (29%), endotoxemic baboon model. A number of parameters were monitored at days 0, 1, 2 and 5-7 after challenge with 2 mg E. coli endotoxin/kg. TNF Mab pretreatment (15 mg/kg) prevented the increase in detectable serum TNF and the early perturbations in cardiovascular function which occurred in the control group. Early metabolic dysfunction was delayed in the TNF MAb group and was attenuated thereafter. Dysfunction of the kidney, liver, and coagulation systems and the increased IL-6 levels were significantly attenuated in the TNF MAb group; neutrophil activation was not affected by TNF MAb. No deaths occurred in the TNF MAb group. These results support the hypothesis that TNF plays a central role in the pathophysiology of endotoxic shock.
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PMID:Efficacy of monoclonal antibody against tumor necrosis factor alpha in an endotoxemic baboon model. 142 24

Tumor necrosis factor alpha (TNF), a monokine produced by mononuclear cells in response to bacterial endotoxin (LPS), creates a syndrome similar to septic shock in animal models. To study whether TNF could induce acute lung injury similar to that seen in gram-negative sepsis, we injected recombinant human TNF (rHuTNF alpha) into guinea pigs and monitored arterial blood gases, leukocyte counts, and left atrial (Pla), pulmonary artery (Ppa), and mean arterial pressures (MAP) serially for 8 h. Pulmonary histopathology was assessed microscopically, and cell counts and 125I-labeled albumin (125I-albumin) in bronchoalveolar lavage (BAL) fluid and lung wet/dry weight ratios were determined. Five groups of animals were studied; the 2 TNF groups received high (1.4 X 10(6) U/kg) or low (1.0 X 10(6) U/kg) doses of rHuTNF alpha, the sepsis group received 2 X 10(9) Escherichia coli/kg intravenously, and the control group received saline. An LPS control group receiving 40 ng/kg E. coli LPS was also included because the rHuTNF alpha contained a small amount of LPS as a contaminant. Pulmonary permeability was assessed by studying the Pla and the BAL fluid/plasma 125I-albumin ratio (permeability index). The permeability index was significantly increased in the high-dose TNF (0.0408 +/- 0.0041, p less than 0.05) and sepsis groups (0.0466 +/- 0.0068, p less than 0.01) relative to controls (0.0215 +/- 0.0028). The wet/dry lung weight ratios were also significantly increased in the high-dose TNF (6.07 +/- 0.29, p less than 0.05) and sepsis groups (6.22 +/- 0.30, p less than 0.05) relative to the control group (5.18 +/- 0.20).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Tumor necrosis factor causes increased pulmonary permeability and edema. Comparison to septic acute lung injury. 305 59

Because of the possible involvement of cytokines in gram-negative septicemia, we investigated serum levels of tumor necrosis factor alpha, interleukin-1 beta, alpha interferon, and gamma interferon in children with gram-negative sepsis and purpura fulminans. We studied 55 patients (ages, 1 month to 19 years) with a clinical diagnosis of sepsis and purpuric lesions who were in shock or had three or more other biologic risk factors. The mortality rate was correlated with the number of risk factors present on admission to the hospital (P = 0.03). Tumor necrosis factor alpha was elevated in 91 percent of the 35 patients tested, interleukin-1 in 21 percent of the 33 patients tested, and gamma interferon in 19 percent of the 32 tested. Alpha interferon levels were within normal limits in the 32 patients tested. Serum levels of tumor necrosis factor alpha were positively correlated with the number of risk factors (P less than 0.05) and negatively correlated with blood fibrinogen levels (P = 0.01). Tumor necrosis factor alpha, interleukin-1, and gamma interferon were significantly higher in patients who died than in the survivors. Alpha interferon levels were similar in the two groups. Serum concentrations of both interleukin-1 and gamma interferon were correlated with concentrations of tumor necrosis factor alpha. These data provide evidence that serum levels of tumor necrosis factor alpha, interleukin-1, and gamma interferon correlate with the severity of meningococcemia in children. The findings may have implications for new therapeutic approaches.
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PMID:Tumor necrosis factor and interleukin-1 in the serum of children with severe infectious purpura. 313 97

The aim of this study was to examine if TNF alpha and IL-6 plasma levels could be of value in diagnosing neonatal sepsis. Tumor necrosis factor alpha (TNF alpha) and interleukin-6 (IL-6) plasma levels were determined in 15 newborn infants with confirmed sepsis (group I), 18 with suspected sepsis (group II) and 22 control infants (group III). In 33 newborns, initially suspected of having sepsis (groups I and II), a positive test result for plasma concentration of TNF alpha (> 70 pg/ml) had a sensitivity of 73% and a specificity of 94%. A positive test result for IL-6 (> 500 pg/ml) had a sensitivity of 80% and a specificity of 78%. When plasma levels of TNF alpha and IL-6 were combined for the diagnosis of neonatal sepsis, a positive test result for both tests had a sensitivity of 60% and a specificity of 100%. When both tests are positive the diagnosis of neonatal sepsis is almost certain (likelihood ratio = infinity). The combination of TNF alpha and IL-6 determinations appears to be a good predictor of neonatal sepsis.
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PMID:Diagnostic value of plasma levels of tumor necrosis factor alpha (TNF alpha) and interleukin-6 (IL-6) in newborns with sepsis. 794 97

Plasma levels of interleukin 1 beta (IL-1 beta), tumor necrosis factor alpha (TNF alpha), interleukin 6 (IL-6), and markers of protein metabolism were determined in 12 burn patients throughout the healing period (day 2 to 21 post-injury) to determine the pattern of variations in plasma cytokine concentration. To establish the relationship between cytokine production and the nutritional status a wide range of severity standpoints (burn surface area ranging from 9% to 82%) was chosen. Interleukin 6 levels were increased in all patients throughout the study period; maximum concentrations (615 +/- 198 pg/mL) were reached on day 4 and correlated (p < 0.01) with the extent of burn injury. Tumor necrosis factor alpha levels were also elevated; they were significantly higher on day 7 in the patients who developed sepsis than in the other patients (67 +/- 21 pg/mL vs. 20 +/- 7 pg/mL; p < 0.05) but did not correlate with the extent of burn injury. Interleukin 1 beta was rarely detected. Cortisolemia on day 7 was inversely correlated with levels of TNF alpha but not with those of IL-6. Interleukin 6 levels correlated positively with protein turnover (phenylalaninemia) and catabolism (3-methylhistidine/creatinine ratio) and negatively with levels of fibronectin and transthyretin. Our data indicate that the systemic cytokine response to burn injury is mainly represented by IL-6. These data also support the hypothesis that IL-6 is a key mediator of the variations in protein metabolism following burn injury.
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PMID:Cytokine response to burn injury: relationship with protein metabolism. 818 61

The pathophysiology of sepsis and septic shock is extremely complex and ultimately involves every physiological pathway. The initiating event is the entrance of endotoxin or similar substances into the blood which initiates the release of multiple mediators. These are designed to react locally and to protect the organism. Their constant release, however, sets in motion up- and down regulations, ultimately resulting in "metabolic anarchy". Tumor necrosis factor alpha and other cytokines trigger several systems, especially coagulation to yield DIC, and the complement system. Many treatment modalities have been developed, most recently those which substitute inhibitors of various systems. Antithrombin III concentrates and potentially protein C concentrates are designed to arrest DIC. C1-esterase inhibitor concentrates should intercept the activation of the complement system and the contact phase of coagulation and its relationship to kinin generation. Even newer approaches entail antibodies to tumor necrosis factor alpha or endotoxin itself. The complex process of sepsis will undoubtedly require a multifaceted therapeutic approach.
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PMID:Perspectives for the future. 822 36

Tumor necrosis factor alpha (TNF alpha) has been implicated as one of the major mediators of the gram-negative septic shock syndrome. In our studies, group B streptococci (GBS) induced the production of TNF alpha by human mononuclear cells in a dose- and time-dependent manner. Human mixed mononuclear cell cultures exposed to an encapsulated (657.6 +/- 71.3 pg/ml; n = 30 preparations) or an unencapsulated transposon mutant of type III GBS (755.8 +/- 54.7 pg/ml; n = 9) produced similar amounts of TNF alpha. Isolated monocytes and culture-derived macrophages produced higher amounts of TNF alpha (1565 +/- 211 and 1790 +/- 928 pg/ml respectively) in response to GBS than did mixed mononuclear cell cultures. In response to GBS, mixed mononuclear cells from neonates produced significantly more TNF alpha (729.1 +/- 45 vs 520.3 +/- 47.2 pg/ml; p = 0.004) than did cells from adults. Examination of specimens from patients with neonatal GBS disease revealed detectable levels of TNF alpha (7 to 424 pg/ml) in the serum of 5 of 10 patients with sepsis, in 5 of 5 urine samples from infants with sepsis, and in the cerebrospinal fluid of 1 patient with meningitis. These results suggest both a major role for TNF alpha in the pathogenesis of human neonatal GBS sepsis and shock and a potential role for immunotherapy directed against this cytokine in this fulminant neonatal bacterial infection.
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PMID:Production of tumor necrosis factor by human cells in vitro and in vivo, induced by group B streptococci. 834 30

The vascular endothelium plays a central role in the regulation of extrinsic fibrinolysis and thus maintains vascular patency through clot dissolution. Plasminogen activation provides an important source of localized proteolytic activity not only during fibrinolysis but also during a variety of other physiological and pathological processes. Numerous studies have indicated that human endothelial cells can directly synthesize and secrete plasminogen activators (PA) and inhibitors of these activators. PAs specifically hydrolyse a single arginine-valine bond in plasminogen, an abundant and widely distributed plasma zymogen, to form the broad spectrum serine protease, plasmin. Tissue type-PA (t-PA) and urokinase type PA (u-PA) forms of PA have been described in endothelial cells, although t-PA production and secretion is elevated most frequently. The tPA form of PA functions predominantly in endothelial cell mediated fibrinolysis, while uPA is involved in tissue remodeling. During inflammatory reactions activated mononuclear phagocytes produce a variety of cytokines which may influence the phenotype of the endothelium through a process termed "endothelial cell activation". Tumor necrosis factor alpha (TNF alpha), a mononuclear cytokine, is a distinct polypeptide of Mr 17,000 and has been implicated as a mediator of gram negative induced sepsis as well as angiogenesis. TNF alpha is known to interact with specific endothelial cell receptors and to alter endothelial coagulant and anticoagulant properties implying that cytokines may be potent modulators of hemostasis. Recent observations have indicated that TNF alpha and lymphotoxin (TNF beta) can promote the expression, synthesis and secretion of urokinase plasminogen activator (uPA) in human endothelial cells. The upregulation of uPA results in an alteration in the fibrinolytic capacity of endothelial cells and allows cells the selective ability to degrade and invade underlying subendothelial extracellular matrix (ECM). Endothelial cells treated with TNF alpha also display, in an in vitro angiogenic assay, the ability to invade Matrigel and reorganize into tube-like structures, unlike control cultures. The effects of TNF alpha on the PA proteolytic system of endothelial cells, the biological significance of this event and potential in vivo consequences will be discussed. In addition, the influence of cytokine regulatory control systems will be described, since it is becoming increasingly clear that cytokines do not act in isolation. The vascular endothelium serves as a widely distributed anatomical interface between the blood and tissue with diverse capabilities, performing distinctive biologic functions at different sites and within specific organs.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Cytokine regulation of endothelial cell extracellular proteolysis. 835 23

We have previously proposed that pro-inflammatory cytokines and nitric oxide (NO) contributed to reversible myocardial depression in patients with sepsis and congestive heart failure. Sepsis and heart failure are also associated with refractoriness to beta-adrenoceptor agonists. Therefore, the chronotropic effects of cytokines and the NO synthase inhibitor, NG-methyl-L-arginine (NMA), on beta-adrenoceptor stimulation of neonatal cardiac myocytes were studied. Tumor necrosis factor alpha, interleukin-1 beta and interleukin-6 but not interleukin-4 or interleukin-5 significantly enhanced spontaneous beating rates compared to untreated myocytes in serum-free media for 48 h (P < 0.01; n = 12 for each). NMA also significantly enhanced spontaneous beating rates (P < 0.01; n = 12 for each). Only interleukin-1 beta treatment resulted in significant nitrite production, immunohistochemical staining for inducible nitric oxide synthase and detection of inducible NO synthase messenger RNA by reverse transcriptase-polymerase chain reaction (RT-PCR). However, tumor necrosis factor alpha, interleukin-1 beta, interleukin-6, and NMA each completely blocked the positive chronotropic effects of the beta-adrenoceptor agonist, isoproterenol (P < 0.01; n = 12 for each). These findings are most consistent with an inducible NO synthase-independent effect of cytokines and NMA on the chronotropic responses of neonatal cardiac myocytes to beta-adrenoceptor stimulation. This effect of cytokines and NMA on adrenergic signaling may involve a myocardial constitutive NO synthase or an NO-independent mechanism.
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PMID:Cytokines and nitric oxide synthase inhibitor as mediators of adrenergic refractoriness in cardiac myocytes. 905 50


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