Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Patients with head injury must overcome central as well as peripheral metabolic insults. In addition to specific tissue damage to the brain, a cellular biochemical cascade occurs that can negatively affect organ function, cause a systemic response to injury, and may cause secondary tissue injury. The metabolites involved in this cascade are numerous and complex. Cytokines are important cell-to-cell communication mediators during injury. It is speculated that cytokines, such as interleukin 1 (IL-1), interleukin 6 (IL-6), tumor necrosis factor (TNF), and interleukin 8 (IL-8), which are found in elevated amounts in both human and basic trials after head injury, play a role in the cellular cascade of injury. Some of the metabolic events produced by small doses of cytokine infusion in animals, as well as humans, include fever, neutrophilia, muscle breakdown, altered amino acid metabolism, depression of serum zinc levels, production of hepatic acute phase reactants, increased endothelial permeability, and expression of endothelial adhesion molecules. These are all known sequelae of severe head injury. Cytokines have also been implicated in organ failure. Infusion of cytokines in basic science trials revealed that organ functions of the gut, liver, and lung are negatively altered by high-dose cytokine infusion. Infusion of certain cytokines has been shown to cause death of brain cells, increase blood-brain barrier permeability, and cause cerebral edema. This suggests that cytokines may also play a role in the sequelae of organ demise. These effects of cytokines have been attenuated in basic trials by blocking the initial signaling system of cytokines or by decreasing serum cytokine activity. We hypothesize that cytokines that are elevated after head injury play a role in the pathology of injury, including altered metabolism and organ demise.
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PMID:Cytokines and metabolic dysfunction after severe head injury. 786 40

Previous studies have demonstrated that the administration of the cytokines, interleukin-1 (IL-1) and tumor necrosis factor (TNF)(20 micrograms/kg) to rats in a fasting state can produce many and perhaps most of the metabolic alterations found in patients with sepsis and injury. The purposes of the present study were 1) to define the metabolic effects of IL-1 and TNF during a fed state provided by continuous intravenous feeding for 20 h and 2) to characterize the unique effects of IL-1 among the overall response to cytokines by using IL-1 receptor antagonist (IL-1RA; 5 mg/kg). The effects were also explored during the endotoxemic condition induced by infusion of 200 micrograms/kg of endotoxin into rats. The results showed that during feeding IL-1 is responsible for the increase in glucose flux and plasma insulin, the development of insulin resistance, and plasma zinc depression during condition mimicking sepsis and injury, similar to effects observed in the fasting state. The changes in energy expenditure have a more complex mechanism. The results also suggested that certain host responses to cytokines or endotoxin, particularly related to protein metabolism, differed between the fed and fasting states. These data may have a special clinical relevance for the insulin-resistant state that develops during severe infection, since using IL-1RA in conjunction with nutritional therapy may offer additional advantages in the treatment of these severe metabolic disorders.
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PMID:Differential effects of interleukin-1 receptor antagonist in cytokine- and endotoxin-treated rats. 786 1

During episodes of acute infection there is a reduced response to epoetin therapy. It is well known that "endogenous pyrogens," such as interleukin-1 (IL-1) and tumor necrosis factor, inhibit erythropoiesis when administered exogenously. To determine whether there is a relationship between these observations, serum samples were obtained from nine patients with chronic renal failure maintained by continuous ambulatory peritoneal dialysis, during and after recovery from bacterial peritonitis, to study the effect of circulating factors on erythropoiesis. Normal human bone marrow-derived erythroid progenitors were cultured in vitro in 5% and 10% patient serum. Depression of the growth of late progenitors, colony-forming units-erythroid (at 10% serum, P = 0.005; 95% confidence intervals, 6.2 and 24.4, respectively), was observed but there was no effect on the earlier progenitors, burst-forming units-erythroid (at 10% serum, P = 0.7; 95% confidence intervals, -18.5 and 13, respectively). The effect was not prevented by antisera to IL-1. Similarly, when added to cultures, IL-1 inhibited the colony-forming units-erythroid and the effect was abrogated by IL-1 antisera. These findings suggest that a circulating soluble factor that is inhibitory to erythropoiesis and may contribute to loss of response to epoetin therapy, is present in cases of peritonitis in continuous ambulatory peritoneal dialysis patients.
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PMID:Serum from continuous ambulatory peritoneal dialysis patients with acute bacterial peritonitis inhibits in vitro erythroid colony formation. 794 11

Most patient with sepsis and septic shock develop significant derangements of myocardial function. The presence of a circulating myocardial depressant substance (MDS) has been suggested to be the major cause of myocardial depression in sepsis and septic shock. MDS is still not fully characterized by chemical means, and there is no consensus regarding its identity. Nevertheless, high levels of MDS activity can be found in sera from patients with sepsis and septic shock. Furthermore, MDS has been shown to have a number of specific characteristics. These characteristics have also been described with tumor necrosis factor-alpha (TNF), a cytokine that is well recognized to be a primary mediator in the pathogenesis of infection, tissue injury, inflammation and shock. In this review it is suggested that TNF is an MDS, and that the cardiovascular injury and myocardial depression during sepsis and septic shock involve a final common pathway, where TNF may have an important role in this common pathway.
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PMID:Tumor necrosis factor-alpha as a myocardial depressant substance. 813 31

We have studied the relationship between the cytokine production induced in vivo by prolonged isometric exercise and the symptom complex marked by fatigue in patients with chronic fatigue syndrome (CFS). Twelve male patients and 13 matched male control subjects undertook an isometric hand-grip exercise protocol utilizing dynamometers. Subjects undertook 30 minutes of exercise, for which the target force was set at 40% of the maximal voluntary contraction and the duty cycle was 50%. Prior to, during, and for 24 hours following the exercise, blood samples were collected and assayed for the presence of cytokines, including interferon-gamma and interferon-alpha, interleukin-1 beta, and tumor necrosis factor-alpha. At those times subjects also completed the Profile of Mood States (POMS) questionnaire, which served as a measure of changes in subjective fatigue. No significant alteration in the level of any of the cytokines in the plasma of patients or control subjects was detected before, during, or after exercise. Surprisingly, the patients' levels of fatigue, depression, and confusion, as measured by the POMS, decreased in response to the exercise. These data do not confirm the presence of an immunologic process correlating with the exacerbation of fatigue after exercise experienced by patients with CFS. Limitations in the study design and in the sensitivity of the cytokine assays may have affected our results.
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PMID:Cytokine production and fatigue in patients with chronic fatigue syndrome and healthy control subjects in response to exercise. 814 42

Because oxygen free radicals have been implicated in the endothelial cell damage and in the myocardial depression occurring during severe sepsis, we investigated whether N-acetyl-L-cysteine (NAC) could influence the oxygen extraction capabilities during an acute reduction in blood flow induced by cardiac tamponade after endotoxin challenge. Sixteen anesthetized, saline-infused, and ventilated dogs received Escherichia coli endotoxin (2 mg/kg) 30 min before tamponade was induced by repeated bolus injections of warm saline into the pericardial space. Thirty minutes before endotoxin administration, nine dogs received NAC (150 mg/kg, followed by a 20 mg.kg-1.h-1 infusion); the other seven dogs served as a control group. The NAC group maintained higher cardiac index, oxygen delivery (DO2), and left ventricular stroke work index, but lower systemic and pulmonary vascular resistance, than the control group. The oxygen uptake (VO2) levels at critical DO2 (DO2crit) were identical in the two groups. However, DO2crit was significantly lower in the NAC than in the control group (8.1 +/- 1.7 vs. 10.8 +/- 1.8 ml.kg-1.min-1, P < 0.01). Critical oxygen extraction ratio and the slope of the VO2-to-DO2-dependent line were higher in the NAC than in the control group (72 +/- 14 vs. 53 +/- 15% and 0.80 vs. 0.56, respectively; both P < 0.05). The peak lactate and the maximal tumor necrosis factor (TNF) levels were lower in the NAC than in the control group (5.2 +/- 0.4 vs. 7.6 +/- 0.4 mM, and 0.14 +/- 0.03 vs. 1.21 +/- 0.58 ng/ml, respectively; both P < 0.01). NAC significantly increased glutathione peroxidase activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Protective effects of N-acetyl-L-cysteine in endotoxemia. 820 75

Cytokines are thought to cause the depression of cytochrome P-450 (CYP)-associated drug metabolism in humans during inflammation and infection. We have examined the role of five cytokines, i.e., interleukin-1 beta, interleukin-4, interleukin-6, tumor necrosis factor-alpha, and interferon-gamma, on the expression of CYP1A2, CYP2C, CYP2E1, CYP3A, and epoxide hydrolase in primary human hepatocyte cultures. Steady state P-450 and epoxide hydrolase mRNA levels, as well as ethoxyresorufin-O-deethylase and nifedipine oxidation activities, which are mainly supported by CYP1A1/1A2 and CYP3A, respectively, were measured. Interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha were found to be the most potent depressors of P-450 enzymes. After 3 days of treatment, both mRNA levels and enzyme activities were depressed, typically by at least 40%, whatever the cytokine and the enzyme considered. Interferon-gamma also suppressed CYP1A2 and CYP2E1 mRNA levels and ethoxyresorufin-O-deethylase activity but had no effect on CYP3A and epoxide hydrolase mRNAs. In addition, interleukin-4 had the opposite effect, compared with other cytokines, on CYP2E1 mRNA, which was increased up to 5-fold; ethoxyresorufin-O-deethylase and nifedipine oxidation activities were not significantly affected. These results provide the first demonstration that various cytokines act directly on human hepatocytes to affect expression of major P-450 genes and that a wide range of responses can be observed among the enzymes for a given cytokine, suggesting that different regulatory mechanisms may be involved.
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PMID:Cytokines down-regulate expression of major cytochrome P-450 enzymes in adult human hepatocytes in primary culture. 823 20

A 24-h pretreatment of mice with diphtheria and tetanus toxoids and whole-cell pertussis vaccines depressed liver cytochrome P-450 and therefore prolonged hexobarbital-induced sleeping time in mice. The depression of liver drug metabolism by a cellular vaccine containing a mutated pertussis toxin was less marked than that induced by the wild-type vaccines, indicating that the mutated vaccine might have lower toxicity in this regard. The wild-type vaccines decreased microsomal P-450 levels by 50%, while the mutated whole-cell vaccine had a less marked effect (a decrease of 30%), paralleling the results obtained in sleeping time experiments. Furthermore, an acellular mutated vaccine did not affect liver drug metabolism, indicating a role of the whole bacterial cell in this side effect. All the cellular vaccines studied induced high serum interleukin-6 levels; on the other hand, the acellular mutated vaccine induced very low interleukin-6 levels, indicating that the whole bacterial cell is also important for interleukin-6 induction. All vaccines studied were very poor tumor necrosis factor inducers.
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PMID:Depression of liver metabolism and induction of cytokine release by diphtheria and tetanus toxoids and pertussis vaccines: role of Bordetella pertussis cells in toxicity. 826 41

Although plasma levels of tumor necrosis factor (TNF) are elevated and hepatocellular dysfunction occurs even in the early hyperdynamic stage of sepsis, the precise mechanism responsible for this dysfunction remains unknown. Although TNF at high doses produces circulatory failure, it is not known whether the dose of TNF that does not adversely affect hemodynamics alters hepatocellular function. To study this, recombinant murine TNF-alpha was infused intravenously (0.05 or 0.25 mg/kg) over 30 min in normal rats. At 1 and 4 h after infusion of TNF-alpha or an equivalent volume of saline, hepatocellular function [i.e., maximum velocity (Vmax) and Michaelis constant (Km)] was assessed using in vivo indocyanine green clearance without blood sampling. Additional parameters measured were as follows: cardiac output by dye dilution, hepatic microcirculation by laser Doppler flowmetry and colloidal carbon infusion, plasma TNF and interleukin-6 (IL-6) by cytokine-dependent cellular assays, and plasma glucose enzymatically. The results indicate that although infusion of 0.05 mg/kg TNF-alpha did not affect Vmax and Km, its infusion at 0.25 mg/kg produced a significant depression of hepatocellular function and markedly increased the synthesis and/or release of IL-6. TNF-alpha-induced hepatocellular dysfunction was not associated with any significant changes in hepatic microcirculation, plasma glucose, cardiac output, and other measured hemodynamic parameters. Thus hepatocellular dysfunction observed after TNF infusion may be due to the direct effect of this cytokine alone or in combination with IL-6.
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PMID:Tumor necrosis factor-alpha produces hepatocellular dysfunction despite normal cardiac output and hepatic microcirculation. 820 42

Although hemorrhage is known to cause increased susceptibility to infection, the precise mechanism remains unknown. Regional hypoxia due to reduced blood flow following hemorrhage appears to be a primary mediator that initiates the cascade of events leading to immunodepression and increased susceptibility to infection. This was evident from depression of lymphocyte functions, production of various lymphokines, macrophage expression of receptors involved in opsonin-mediated phagocytosis, and antigen presentation function of peritoneal, splenic, and Kupffer cells following hemorrhage. The depression in various immune functions is apparent immediately after hemorrhage and persists for a prolonged period of time, despite volume resuscitation. Furthermore, it appears that the increased release of systemic mediators, such as interleukin-1 (IL-1), IL-6, tumor necrosis factor, transforming growth factor type beta, and prostaglandin E2 is associated with marked depression in immune responses and increased susceptibility to infection following hemorrhage.
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PMID:Mechanism of increased susceptibility to infection following hemorrhage. 843 1


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