Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0030193 (pain)
 261,466 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Five patients with advanced arteriosclerosis obliterans of the lower extremities, as evidenced by resting pain, ischaemic ulcers, and focal necrosis, received intra-arterial infusions of prostacyclin at doses of 5--10 ng/kg/min for 72 h. Within 2 days of termination of the infusion, pain at rest had disappeared in all patients. In three of the five, the necrosis had completely regressed and the ischaemic ulcers healed within 2 months. The other two patients showed considerable improvement. Prostacyclin therapy was not associated with changes in the radiographic appearance of the major blood-vessels. However, muscle blood-flow, as measured by xenon-133 clearance, was significantly increased both during prostacyclin infusion and for the 6 weeks of measurement after its termination.
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PMID:Successful therapy of advanced arteriosclerosis obliterans with prostacyclin. 8 35

In chemical terms the mediators of inflammation can be divided in amines (histamine, serotonine), peptides (ECF-A, bradykinin), proteins (lysosomal enzymes), and lipids. They mainly act at three levels: 1.) They induce vascular reactions and are responsible for the classical symptoms of inflammation, 2.) they define and modulate the cellular response towards the inflammatory stimulus such as the morphology of the tissue infiltrate, 3.) they act on haemostasis by interaction with platelets. While in the past investigations on classical mediators have dominated research, recently the biological role of lipid mediators has been appreciated. They can be detected only in minute quantities; they often have a short half-life and are not preformed within the cells. The most common precursor of the lipid mediators is arachidonic acid. This unsaturated fatty acid is generated from phospholipids after phospholipase activation of cells and is transformed by the enzyme cycloxygenase to a series of compounds such as the prostaglandins. They induce the classical signs of inflammation such asvescular dilatation, increase in permeability, pain, hyperalgesia etc. By the same process, the thromboxanes and prostacycline are generated which mainly act on the coagulation system. Various products are obtained from arachidonic acid via lipoxygenase activation. To these belong a factor chemically not completely defined with classical SRS-A activity; there is strong evidence that PAF and ECF are formed on the same line. Experiments in recent years have supported the idea that neutrophils and mononuclear cells are by far the main producers of lipid mediators, thus indicating the cellular interdependence during the inflammatory process.
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PMID:[Origin and biological role of lipid mediators during inflammation (author's transl)]. 12 Mar 7

Kinins are potent mediators of rheumatoid inflammation. The components of the kinin-forming system are hyperactive in RA. Excessive release of kinins in the synovial fluid can produce oedema, pain and loss of functions due to activation of B1 and B2 receptors. These receptors could be stimulated via injury, trauma, coagulation pathways (Hageman factor and thrombin) and immune complexes. The activated B1 and B2 receptors might cause release of other powerful non-cytokines and cytokines mediators of inflammation, for example, PGE2, PGI2, LTs, histamine, PAF, IL-1 and TNF derived mainly from polymorphonuclear leukocytes, macrophages, endothelial cells and synovial tissue. These mediators are capable of inducing bone and cartilage damage, hypertrophic synovitis, vessels proliferation, inflammatory cells migration, and possibly angiogenesis in pannus formation. These pathological changes, however, are not yet defined in human model of chronic inflammation (RA). Hence, the role of kinin and its interacting inflammatory mediators would soon start to clarify the detailed questions they revealed in clinical and experimental models of chronic inflammatory joint diseases. Several B1 and B2 receptor antagonists are being synthesized in an attempt to study the molecular functions of kinins in inflammatory processes (RA, periodontitis and osteomyelitis), and they represent and important area for continued research in rheumatology. Future development of specific, potent and stable B1 and B2 receptor antagonists or combined B1 and B2 antagonists with y-IFN might serve as pharmacological basis of more effective rationally-based therapies for RA. This may lead to significant advances in our knowledge of the mechanisms and therapeutics of rheumatic diseases.
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PMID:Involvement of the kinin-forming system in the physiopathology of rheumatoid inflammation. 133 58

Iloprost is an analogue of epoprostenol (prostacyclin; PGI2; a potent but short-lived prostanoid mainly produced in the vascular endothelium) and mimics the pharmacodynamic properties of this compound, namely: inhibition of platelet aggregation, vasodilatation and, as yet ill-defined, cytoprotection. Improved metabolic and, in particular, chemical stability enhance the clinical utility of iloprost. When administered as an intermittent intravenous infusion at less than or equal to 2 ng/kg/min for 2 to 4 weeks, iloprost reduced rest pain and improved ulcer healing in 40 to 60% of patients with critical leg ischaemia, including diabetic patients, and delayed amputation in the majority of responding individuals. Similar benefits have been seen in thromboangiitis obliterans and, in patients with severe Raynaud's phenomenon, shorter courses of therapy reduced the frequency, intensity and duration of ischaemic episodes for at least 6 weeks. The very few comparative trials reported to date (i.e. vs nifedipine in Raynaud's phenomenon; vs low-dose aspirin in thromboangiitis obliterans) have favoured iloprost, but comparisons with more established agents are needed to assess this drug's value in less severe forms of peripheral ischaemia, such as intermittent claudication. At present, iloprost is administered intravenously and this is a limitation to treatment. The potent, rapidly reversible antiplatelet activity of iloprost suits it for use in extracorporeal circulation and for the intraoperative management of heparin-induced platelet activation. Although results in animal models of ischaemic myocardial injury are encouraging, preliminary clinical experience in patients with myocardial ischaemia or infarction has been disappointing. Most patients tolerate iloprost infusion rates of up to 2 ng/kg/min. Headache and flushing are extremely common and are the suggested end-point of dose titration, as higher doses are associated with a significant incidence of gastrointestinal distress and, ultimately, hypotension. Thus, iloprost provides a pharmacotherapeutic option for patients with severe peripheral vascular disease, a condition for which few alternative drug therapies exist. Its potent but short-lived effects make it well-suited to certain therapeutic niches such as the management of intraoperative platelet activation. Prostanoid analogues have far-reaching therapeutic potential and further experience with iloprost will no doubt help to define its clinical applications.
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PMID:Iloprost. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in peripheral vascular disease, myocardial ischaemia and extracorporeal circulation procedures. 137 60

The joint is a relatively rare localization for osteoid osteoma. The location of the tumor and the concomitant synovitis-explain the peculiarity of the clinical features, which makes differential diagnosis with inflammatory diseases of the joint difficult. The authors report the results of three cases of intra-articular osteoid osteoma in which it was possible to determine the levels of prostaglandin (PGE2) and prostacyclin (PGI2), which are synthesized by the tumoral tissue. The increased production of these substances, which can reach up to 70 times their production in normal tissue, explain both the character of the pain and the origin of the synovitis which is so commonly found in this kind of tumor. The results of this study confirm the ability of the neoplastic tissue to produce high quantities of mediators of inflammation and enable the authors to formulate a theory as to the pathogenesis of the concomitant reactive synovitis observed in cases of intra-articular osteoid osteoma.
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PMID:Intra-articular osteoid osteoma. 139 36

The effects of prostaglandin I2 on the discharge properties of fine articular afferents (group III and group IV fibers) in the cat were examined by extracellular recordings from single units dissected from the medial articular nerve of the knee joint. Prostaglandin I2 was applied intra-arterially close to the joint in doses of 0.3-30 micrograms per 0.3 ml bolus injection, and its effects on the spontaneous activity as well as on discharges evoked by mechanical and chemical stimulation (bradykinin) were monitored. Prostaglandin E2 was also applied and the effects of prostaglandins I2 and E2 on particular units were compared. An excitatory effect of prostaglandin I2 was observed in 49% of 37 group III and in 37% of 27 group IV units. A sensitization to passive movements of the joint occurred in 71% of 31 group III and 48% of 21 group IV units. Sixty-seven per cent of 32 units (groups III and IV) were both excited and sensitized by prostaglandin I2 to movements of 27% were sensitized but not excited. In 64% of 11 group III and 63% of eight group IV units studied the responses to bradykinin were enhanced by prostaglandin I2. Prostaglandin E2 had qualitatively similar effects as prostaglandin I2 but excited and sensitized a lower proportion of articular afferents. Forty-one per cent of the units were sensitive to both prostaglandins but 26% of the fibers were only sensitive to prostaglandin I2. None of the units was exclusively sensitive to prostaglandin E2. In general, the excitatory and sensitizing effects of prostaglandin E2 had a longer duration than those exerted by prostaglandin I2. We conclude that prostaglandin I2 increases the sensitivity to mechanical stimuli as well as to chemical stimulation by bradykinin in the majority of articular group III and group IV fibers. Moreover, in a large proportion of articular afferents, prostaglandin I2 had an excitatory effect. Thus, prostaglandin I2 may be an inflammatory mediator which is important for inflammation-evoked activity in slowly conducting afferents and it may participate in the development of arthritic hyperalgesia and pain.
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PMID:Inflammatory mediators and nociception in the joint: excitation and sensitization of slowly conducting afferent fibers of cat's knee by prostaglandin I2. 140 58

The balance between prostacyclin and thromboxane has been suggested to be of great importance for the maintenance of patency in veins. In order to investigate prostacyclin and thromboxane release, segments from the human saphenous veins were investigated in 53 patients. Twenty-seven patients (10 males, 17 females) underwent surgery for varicose veins. Twenty-six patients (14 nondiabetics, 12 diabetics) underwent surgery for lower limb ischemia (rest pain or gangrene) with use of the saphenous vein as arterial conduit. Vein segments were gently excised and perfused ex vivo for five 15 minute periods, with a balanced salt solution and determination of the stable degradation products 6-keto-PGF1 alpha and TxB2. Saphenous veins from patients with varicose veins had an initial prostacyclin release of 61 +/- 13 pg/mm2/15 min declining to 4 +/- 1 pg/mm2/15 min after 60 min (p < 0.001) and increasing after addition to arachidonic acid to 37 +/- 7 pg/mm2/15 min (p < 0.001). Segments from nondiabetic patients with lower limb ischemia did not differ from those of varicectomy patients, but diabetic segments had a significantly lower prostacyclin release than both these groups, 34 +/- 11 pg/mm2/15 min, 1 +/- 1 pg/mm2/15 min, and 7 +/- 5 pg/mm2/15 min, respectively (p < 0.05). The addition of arachidonic acid failed to increase the prostacyclin release in diabetics. Three patients from each group were studied regarding thromboxane release and there was almost no detectable thromboxane in any group. These findings suggest that diabetics have a lowered prostacyclin release from the saphenous vein and that the deficiency is at the cyclo-oxygenase level.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Prostacyclin release from the human saphenous vein in diabetics in lower than in nondiabetics. 145 86

Changes in platelet function have been observed for sickle cell disease (SCD). Levels of the arachidonic acid metabolites, thromboxane A2 (released by stimulated platelets) and prostacyclin (released from vascular endothelium), which stimulate and inhibit platelets, respectively, have been implicated in overall regulation of platelet function. Circulating basal levels of thromboxane and prostacyclin were determined in 1) a group of SCD volunteers (n = 21; at half-yearly steady state intervals and also at 24 hr, 72 hr, and 7 days after start of pain crisis) and 2) an age-, sex-, and race-matched control group (n = 18; single determinations). Circulating levels of beta-thromboglobulin (beta-TG), as well as thrombin (clotting)-stimulated platelet release of thromboxane, were also determined. Statistically significant decreases were found for prostacyclin, basal thromboxane, and thrombin-induced (maximal) thromboxane (alone or per platelet), for steady state SCD vs. normal controls. In addition, significant increases in maximal thromboxane were identified in crises (24, 72 hr) compared with steady state. Crisis beta-TG (24 hr) was significantly elevated compared with controls or steady state SCD. The ratio of basal thromboxane to prostacyclin was increased in crisis, but not significantly. Crisis frequency may correlate in part with changes in platelet function: steady state maximal thromboxane and released thromboxane per platelet were significantly lower in SCD volunteers who had crises during the study vs. those who did not (equivalent study time). The data support altered platelet function in SCD, possibly refractoriness (desensitization), manifest as decreased thromboxane release, to thrombin and/or other stimuli: alternate explanations are discussed.
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PMID:Platelet regulatory prostanoids and platelet release products in sickle cell disease. 153 87

The effect of prostacyclin (PGI2) on red blood cell deformability is still controversial. The authors have evaluated some hemorrheologic parameters during PGI2 infusion to patients with severe obstructive peripheral arterial disease not suitable for surgery and not responsive to other medical treatments. PGI2 infusion resulted in a positive clinical effect in 12 of 16 patients, who experienced a significant improvement of their rest pain lasting from two days to more than seven months. Hematocrit, platelet count, and fibrinogen were not modified during PGI2 infusion whereas leukocyte count rose significantly. The evaluation of red blood cell filterability (VRBC) (volume of RBC filtered in one minute) by a whole blood filtration technique showed no significant changes during PGI2 treatment. However, since whole blood filterability is negatively correlated to leukocyte count, a specific regression line was elaborated to remove the potential negative influence of the increased leukocyte counts. VRBC values adjusted to a standard leukocyte number significantly increased during PGI2 treatment.
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PMID:Failure to demonstrate beneficial effect of prostacyclin (PGI2) infusion on red blood cell deformability in patients with peripheral vascular disease: a possible role of the leukocytes. 155 17

Normal nociceptors are sensitized by hyperalgesic mediators such as eicosanoids and tachykinins. The possibility that these mediators contribute to hyperalgesic pain associated with neural injury was investigated by examining their effects on the excitability of injured afferent nerve endings. In amounts that sensitize normal nociceptors and are hyperalgesic in normal skin, the eicosanoids prostaglandin I2 (PGI2), and 8(R),15(S)-dihydroxyicosatetraenoic acid (8(R),15(S)-diHETE) both excited some C-fibers in chronic neuromas of rat sciatic nerve. In contrast, the selective tachykinin-receptor agonists septide and senktide did not excite C-fibers. None of the mediators affected A-fibers. We conclude that PGI2 and 8(R),15(S)-diHETE may contribute to post-injury pain and hyperalgesia by an action on injured afferent endings.
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PMID:Eicosanoids, but not tachykinins, excite C-fiber endings in rat sciatic nerve-end neuromas. 161 Oct 31


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