Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cytokine tumor necrosis factor (TNF-alpha) is a pleotrophic polypeptide that plays a significant role in brain immune and inflammatory activities. TNF-alpha is produced in the brain in response to various pathological processes such as infectious agents [e.g., human immunodeficiency virus (HIV) and malaria], ischemia, and trauma. TNF-alpha mRNA is rapidly produced in response to brain ischemia within 1 h, reaches a peak at 6-12 h post ischemia, and subsides 1-2 days later. TNF-alpha mRNA expression corresponds in a temporal fashion to other cytokines such as interleukin (IL)-6, cytokine-induced neutrophil chemoattractant (KC), and IL-1 and precedes the infiltration of inflammatory cells into the injured zone. TNF-alpha is present early in neuronal cells in and around the ischemic tissue (penumbra), yet at later time points, the peptide is found in macrophages in the infarcted tissue. TNF-alpha has been demonstrated to cause expression of proadhesive molecules on the endothelium, which results in leukocyte accumulation, adherence, and migration from capillaries into the brain. Furthermore, TNF-alpha activates glial cells, thereby regulating tissue remodeling, gliosis, and scar formation. Thus, evidence is emerging in support of a role for TNF-alpha in injury induced by infectious, immune, toxic, traumatic, and ischemic stimuli. TNF-alpha promotes inflammation by stimulation of capillary endothelial cell proinflammatory responses and thereby provides leukocyte adhesion and infiltration into the ischemic brain. The evidence generated so far suggests that agents that suppress TNF-alpha's production or actions will reduce leukocyte infiltration into ischemic brain regions and thereby diminish the extent of tissue loss.
 ...
PMID:Cytokines, inflammation, and brain injury: role of tumor necrosis factor-alpha. 788 Jul 18

Transient global cerebral ischemia induces selective neuronal degeneration in the adult rat hippocampus, which is both preceded and accompanied by activation of microglia and astrocytes. Altered expression patterns of cytokines and growth factors might influence the postischemic neuron-glial interactions as well as the degenerative neuronal processes. Northern blotting of hippocampal tissue from ischemic animals revealed elevated levels of transforming growth factor beta-1 (TGF-beta 1) mRNA, and in the present in situ hybridization study we examine the endogenous expression and cellular localization of TGF-beta 1 mRNA in the adult rat hippocampus at various intervals following 10 min of global cerebral ischemia. Six hours after ischemia, a diffuse expression of TGF-beta 1 mRNA was found throughout the brain, which further intensified until Day 2 and thereafter subsided. In parallel, a massive increase of signal was observed in the hilus fascia dentata from Day 1 and in area CA1 from Day 2 to 4, both areas displaying selective neuronal degeneration. Peak levels of TGF-beta 1 mRNA were found in the hilus around Day 4, whereas expression in the CA1 area persisted through Day 21, the latest time point examined. A similar biphasic response, consisting of a transient, generalized reaction and a persistent lesion-associated activation in areas undergoing selective neuronal degeneration, was previously described for microglia and is reconfirmed in the present study. Cells of the microglial/macrophage lineage thus include the potent modulatory cytokine TGF-beta 1 in their potential repertoire of responses to both CNS activation and lesioning.
 ...
PMID:Cytokines in cerebral ischemia: expression of transforming growth factor beta-1 (TGF-beta 1) mRNA in the postischemic adult rat hippocampus. 789 6

In a prospective, randomized, double-blind, placebo-controlled trial, rhSOD was given to cadaveric renal allograft recipients intravenously in a dose of 200 mg during surgery, and its effect on both acute and chronic rejection was investigated. The results showed that rhSOD exerts a beneficial effect on acute rejection episodes as indicated by a statistically significant reduction of first acute rejection episodes to 18.5% compared with 33.3% in controls, and a reduction in early irreversible acute rejection to 3.7% compared with 12.5% in controls. With regard to longterm results, there was a statistically significant improvement in the actual 5-year graft survival rate for rhSOD-treated patients to 68% (with a corresponding 13-year half-life) compared with 50% in controls (with a corresponding 6-year half-life). The incidence of acute rejection episodes did not prove to be a risk factor for long-term graft outcome. Rather only the combination of acute rejection episodes and the presence of uninfluenced reperfusion injury appeared to have a detrimental effect on long-term prognosis. The beneficial effect of rhSOD observed in this trial is not well understood, although one can assume that the effect is brought about by interference of rhSOD with ischemia or reperfusion injury to the allograft by oxygen-free radicals. In this sense, rhSOD may mitigate increased MHC expression and presentation, cytokine-adhesion molecule expression, and APC activation induced by reperfusion injury. In addition, in accordance with the "response-to-injury" hypothesis to explain the pathogenesis of arteriosclerosis, rhSOD may mitigate acceleration of chronic obliterative rejection or arterio-/arteriolosclerosis induced by reperfusion injury. In this sense, rhSOD may act indirectly by reducing acute rejection-mediated endothelial injury, or directly, by ablation of reperfusion-mediated acute endothelial injury.
 ...
PMID:The impact of free radical-mediated reperfusion injury on acute and chronic rejection events following cadaveric renal transplantation. 791 55

Experimental and clinical observations indicate that the liver allograft is less immunogenic than other organ transplants and can promote immune tolerance. Because interleukin-10 recently emerged as a macrophage and T-cell-derived cytokine with potent immunosuppressive properties, we studied its production in 28 patients undergoing orthotopic liver transplantation. Plasma levels of immunoreactive interleukin-10 dramatically increased within 2 hr after liver allograft reperfusion, with peak levels ranging between 214 and 4998 pg/ml (median = 677 pg/ml). This systemic release of interleukin-10 was transient because it returned to low levels by 48 hr (range = 26 to 51 pg/ml). The higher interleukin-10 levels measured in right atrial blood as compared with portal blood indicated that interleukin-10 was most likely synthesized within the liver graft. To get insight into the cellular origin of interleukin-10, we also measured serum levels of interleukin-4 and interferon-gamma, both produced by T cells, and interleukin-8, a cytokine secreted by macrophages, in eight patients. Interleukin-4 and interferon-gamma levels remained undetectable in most of the patients, whereas interleukin-8 levels paralleled those of interleukin-10. Portal endotoxemia was probably not involved in interleukin-10 production because endotoxin levels remained low (< 20 pg/ml) before and after liver allograft reperfusion. Interleukin-10 plasma levels did not correlate either with cold ischemia time or with the occurrence of rejection episodes. We conclude that orthotopic liver transplantation is associated with a massive release of interleukin-10 and interleukin-8, most likely produced by allograft macrophages.
 ...
PMID:Systemic release of interleukin-10 during orthotopic liver transplantation. 792 30

Adenosine is an endogenous nucleoside that can modulate the function of cells involved in the inflammatory response, such as polymorphonuclear leukocytes (PMN) and monocytes. Production and release of cytokines by activated mononuclear phagocytes is an important event in the pathogenesis of ischemia-reperfusion injury, a pathologic phenomenon that is associated with excessive ATP catabolism and subsequent local release of adenosine. The "retaliatory" metabolite adenosine has been shown to interfere with PMN function, thereby attenuating the deleterious consequences of ischemia and reperfusion. In this study, we demonstrate that adenosine inhibits the production of TNF-alpha, IL-6, and IL-8 by LPS-activated human monocytes with a differential potency. The A2 receptor-specific adenosine analogues 2-chloroadenosine and 5'-N-ethylcarboxamidoadenosine (NECA) were most effective in attenuating LPS-induced cytokine production, whereas the A1-selective adenosine analogue N6-cyclopentyladenosine (CPA) was less effective, indicating that inhibition of cytokine production by adenosine is primarily an A2 receptor-mediated event. The observed inhibitory effects were not restricted to endotoxin-induced cytokine production, because adenosine also inhibited TNF-alpha production by monocytes stimulated with the proinflammatory cytokine IL-1 beta. Again, 2-chloroadenosine and NECA reduced IL-beta-induced TNF-alpha production more potently than CPA. In contrast, adenosine enhanced production of IL-6 and IL-8 by monocytes stimulated with IL-1 beta. Furthermore, only 2-chloroadenosine, but not NECA, strongly inhibited cytokine-induced IL-6 and IL-8 production. These results suggest an additional A2 receptor-mediated mechanism of retaliatory action of adenosine under pathologic conditions where cytokine production by activated mononuclear phagocytes is involved, such as ischemia-reperfusion injury and septic shock.
 ...
PMID:Differential regulatory effects of adenosine on cytokine release by activated human monocytes. 793 Jun 19

Mechanistic investigations into the pathophysiology of acute liver failure after hepatic ischemia and reperfusion revealed that reactive oxygen species are generated intracellularly only after prolonged periods of ischemia. Parenchymal cell injury during ischemia seems to be a prerequisite for a significant intracellular oxidant stress. However, after shorter periods of ischemia without significant ischemic injury, reactive oxygen is formed predominantly in the extracellular (vascular) space with Kupffer cells and later also with neutrophils as the main sources. Both cell types generate a variety of inflammatory and cytotoxic mediators and are involved in a complex, self-aggravating injury mechanism leading to massive liver cell necrosis and a systemic inflammatory reaction, which may also affect other organs. Integrins and cellular adhesion molecules are critical for neutrophil accumulation and formation of reactive oxygen. An important aspect of the pathogenesis is the manifestation of a "priming" effect for enhanced reactive oxygen formation, but not cytokine generation by Kupffer cells and neutrophils. Priming of phagocytes means that even after short periods of hepatic ischemia (20-30 min) with only moderate reperfusion injury, secondary stimuli, e.g. as generated during sepsis, can cause a potentiation of the postischemic oxidant stress and liver injury and may eventually lead to acute liver failure.
 ...
PMID:[Pathogenetic mechanisms of acute liver failure]. 802 97

Previous studies in vitro have shown an important role for intercellular adhesion molecule-1 (ICAM-1) in adherence interactions of canine neutrophils with canine jugular vein endothelial cells and in cytotoxicity of canine neutrophils for adult cardiac myocytes. To evaluate the regulation of ICAM-1 in myocardial inflammation and its role in the pathogenesis of myocardial ischemia and reperfusion, a series of in vivo and ex vivo studies were performed in canine animals. Systemic administration of LPS elicited ICAM-1 mRNA in several tissues, including myocardium, which demonstrated increasing ICAM-1 staining on intercalated discs of cardiac myocytes. In ischemia and reperfusion protocols: (a) ICAM-1 mRNA was found in ischemic segments within 1 h of reperfusion and in both ischemic and normally perfused segments by 24 h of reperfusion; (b) expression of ICAM-1 was detected in cardiac myocytes in the ischemic region by 6 h of reperfusion; increased expression was seen thereafter as a function of time; (c) post-ischemic (but not preischemic) cardiac lymph collected at intervals from 1 to 24 h after reperfusion elicited ICAM-1 mRNA, ICAM-1 expression, and ICAM-1-dependent neutrophil adhesion in canine jugular vein endothelial cells and in cardiac myocytes with peak cytokine activity seen by 1 h; (d) extravascular localization of neutrophils was detected in ischemic areas only, and was associated with endothelium bearing high levels of ICAM-1 within 1 h of reperfusion; infiltration increased thereafter in association with increasing levels of ICAM-1 mRNA in myocardial segments and increasing levels of ICAM-1 expression on cardiac myocytes. These findings provide the first direct evidence for inflammatory regulation of ICAM-1 in ischemic and reperfused canine myocardium. They support the hypothesis that ICAM-1 participates in neutrophil-mediated myocardial damage.
 ...
PMID:Regulation of intercellular adhesion molecule-1 (ICAM-1) in ischemic and reperfused canine myocardium. 810 98

The myocardial ischemia and reperfusion injury is caused by the re-introduction of coronary circulation in ischemic myocardial tissues. A number of experiments demonstrate that immunological response such as adherence of neutrophils to endothelial cells play a critical role in reperfusion injury. In this paper, the effect of global ischemia and reperfusion on the expression of cytokine genes by myocardial tissues as well as cell adhesion molecules by neutrophils were studied by using Langendorff model. Cardiac dysfunction and immunological response in 25 min global ischemia at 37.5 degrees C followed by 60 min reperfusion were studied in isolated rat heart perfused with blood supplied from support rat (Langendorff model). Cardiac functions were measured with a left intraventricular balloon. The mean post-experimental reduction of the left ventricular end-systolic pressure were 87.5 +/- 1.6% of pre-experimental level in the control perfusion group and 55.5 +/- 5.8% in the reperfusion group. Immunofluorescence flow cytometry showed that ischemia and reperfusion injury did not affect the expression of adhesion molecules on neutrophils which were isolated from perfused blood samples. Cytokine gene expression was analyzed by direct analysis of mRNA obtained from the blood-perfused, isolated rat heart. The level of expression of the cytokine genes was assessed using semiquantitative reverse transcriptase-polymerase chain reaction (semiquantitative RT-PCR). IL-6, IL-8, IFN-gamma, TNF-alpha were expressed in normal heart tissue at low level and were upregulated following ischemia and reperfusion. IL-1 beta, MCP-1 and IL-1 receptor antagonist were not expressed at detectable level in normal heart but were induced following global ischemia. IL-1 alpha was not expressed at detectable level in normal heart but was induced following reperfusion of the ischemic heart. Histological examination of myocardial tissue from the reperfusion group revealed no evidence of myocardial necrosis. Only a mild interstitial edema as well as weak focal hemorrhage was detected after reperfusion of ischemic hearts. These results suggest that there is a process which causes early stage of post-ischemic myocardial dysfunction without involving myocardial necrosis nor infiltration of inflammatory cells.
 ...
PMID:[Cardiac dysfunction and endogenous cytokines in global ischemia and reperfusion injury]. 811 7

Although many new antibiotics became available for clinical use, intractable bacterial infections are still major cause of morbidity and mortality in surgical patients. The infections are attributable to multiple factors. Surgical stress such as extensive burns and major surgery results in the depressed host-defense function, which is mediated by cytokine responses. Necrotic tissue, ischemia, hematoma, cholelithiasis, foreign bodies, indwelling catheters, intra-tracheal tubes, and other medical devices are local factors making infection resistant to ordinary chemotherapy. Multi-resistant bacteria such as methicillin resistant Staphylococcus aureus and Pseudomonas, and ampicillin resistant enterococci are the main bacteria causing the infections. 32% of surgical specimens isolated two or more bacteria, making the chemotherapy difficult in clinical setting. Importance of surgical drainage, removal of necrosis and the devices are emphasized.
 ...
PMID:[Intractable bacterial infections in surgical patients]. 812 4

Interleukin (IL-4) is a pluripotent cytokine that stimulates proliferation of activated T-cells and has antineoplastic activity against human renal tumors in animal systems. In phase I trials, IL-4 could be tolerated at doses up to 20 micrograms/kg, with dose-limiting toxicities consisting of fever, fluid retention, nasal congestion, and mucositis. We report the results of two separate Phase II trials of IL-4 in 30 patients with metastatic malignant melanoma and 19 patients with advanced renal cancer. IL-4 was administered intravenously every 8 h for 14 doses in two 5-day courses separated by a 9-day interval. The first 27 patients were treated at a dose of 800 micrograms/m2, but after three of these patients developed cardiac toxicities, the dose was decreased to 600 micrograms/m2. One complete response occurred in a patient with metastatic melanoma (duration > or = 30 months). No responses were seen among the patients with renal cancer. The most frequent side effects were fever, nausea, malaise, nasal congestion, and diarrhea. Reversible hepatic and renal dysfunction were also common. Hypotension was infrequent, but transient weight gain due to fluid retention was common. The major life-threatening toxicities were cardiac and gastrointestinal. Suspected cardiac ischemia was observed in two patients, pericarditis in one, and arrhythmias in two. Three patients had major upper gastrointestinal bleeding without evidence of local tumor. We conclude that IL-4, when given as a single agent on this schedule at maximum tolerated dose, does not possess meaningful activity in renal cancer or melanoma.
 ...
PMID:Phase II studies of recombinant human interleukin-4 in advanced renal cancer and malignant melanoma. 813 48


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>