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)

Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenase (COX) activity, thereby suppressing the synthesis of proinflammatory prostaglandins. The identification and molecular-biological characterization of an inducible COX isoform (COX-2) in inflammatory cells led to the hypothesis that a selective inhibition of COX-2 would result in relief of inflammation and pain without causing the COX-1-dependent side effects (gastrointestinal ulceration, platelet dysfunction, kidney damage) of conventional NSAIDs. On the basis of data obtained in several laboratories by means of the "human whole blood assay" there is now convincing evidence that none of the currently available NSAIDs is a selective COX-2 inhibitor. Meanwhile, the specific COX-2 inhibitors celecoxib and rofecoxib are being tested worldwide in phase III clinical trials on patients with rheumatoid arthritis and osteoarthritis. However, the simple concept of COX-2 being an exclusively proinflammatory inducible enzyme cannot be upheld any longer. In addition, COX-2 is expressed constitutively in brain, spinal cord and kidney, as well as in numerous other organs. In the present review the perspectives and possible risks of specific COX-2 inhibitors are discussed, as well as additional indications for their implementation (e.g. colon cancer).
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PMID:[Specific COX-2 inhibitors: prospects of therapy with new analgesic and anti-inflammatory substances]. 1009 92

Animal and human data demonstrate that cyclooxygenase (COX)-2 upregulation in osteoarthritis and rheumatoid arthritis is associated with the pain and inflammation of the disease state. The COX-1 isoform, however, is a constitutive enzyme with homeostatic functions. Unlike conventional nonsteroidal anti-inflammatory drugs, which inhibit both forms of the COX enzyme, celecoxib inhibits COX-2 preferentially to COX-1 in vitro. Celecoxib reversed signs of arthritis and pain in an animal model as effectively as indomethacin. Data from murine studies as well as in vitro and epidemiologic data indicate that COX-2 plays a role in the development of colon cancer, and epidemiologic studies also suggest that COX inhibition can slow the progression of Alzheimer's disease.
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PMID:Role of cyclooxygenase-1 and -2 in health and disease. 1019 97

The existence of two distinct isoforms of cyclooxygenase (COX), which convert arachidonic acid to prostanoids, is now well established. COX-1, which is constitutively expressed in many tissues (including the gastrointestinal tract, platelets, and kidney) is responsible for producing prostanoids that regulate normal housekeeping or physiologic functions. In contrast, COX-2 is the inducible form responsible for the production of prostanoids in response to a variety of evoking stimuli in different tissues and for mediation of inflammation and pain in certain diseases. Since the identification of COX-2, a great deal of research has been devoted to elucidating and understanding its molecular and physiologic characteristics. As a result of research into the differences between COX-1 and COX-2, new insights into the role of each isoform in normal homeostasis and in their responses to exogenous stimuli have emerged. Besides its induction in cells at inflammatory sites, COX-2 is known to be induced in the kidney in response to sodium depletion or in hyperfiltration states; in postsynaptic excitatory neurons in the brain after electroconvulsive stimulation, in the ovary and uterus during ovulation and implantation; in intestinal epithelium after bacterial infection; as well as in colon adenoma and carcinoma cells. These findings, largely from animal studies, have suggested a broader spectrum of biologic activity of COX-2 and potential alterations of specific physiologic or protective mechanisms by inhibition of COX-2, as well as potential new clinical targets of therapy with COX-2 inhibitors. As COX-2 appears to play an important role in pathologic processes other than pain and inflammation, ongoing research is investigating the potential utility of COX-2 inhibitors in other conditions, such as colonic polyposis, colorectal cancer, and Alzheimer's disease.
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PMID:Specific COX-2 inhibitors in arthritis, oncology, and beyond: where is the science headed? 1022 37

Nonsteroidal antiinflammatory drugs (NSAID) are effective for the relief of pain and inflammation, yet their use is tempered by the development of side effects, primarily in the gastrointestinal (GI) tract. It is now known that inhibition of the enzyme cyclooxygenase (COX) is the principal mechanism for both the efficacy and the toxicity of NSAID. Recent research has shown that COX exists as at least two isoenzymes, COX-1 and COX-2. Compelling evidence suggests that COX-1 synthesizes prostaglandins that are involved in the regulation of normal cell activity (including G1 cytoprotection), whereas COX-2 appears to produce prostaglandins mainly at sites of inflammation. These findings led to the search for compounds that would inhibit COX-2 without affecting COX-1. Several agents are under investigation in this new therapeutic category, including celecoxib (SC-58635). Celecoxib was developed as an antiinflammatory and analgesic agent, and has been studied in preclinical studies and in clinical trials. This paper focuses on the results of 5 key clinical trials of celecoxib: an efficacy trial in dental pain, a 2 week osteoarthritis (OA) efficacy trial, a 4 week rheumatoid arthritis (RA) efficacy trial, a one week endoscopic study of GI mucosal effects, and a 10 day study of effects on platelet function. The arthritis trials identified celecoxib doses that were effective in treating OA and RA and that were distinguished from placebo on standard arthritis scales. In the upper GI endoscopy study, no ulcers occurred in subjects receiving celecoxib or placebo, whereas 19% of subjects receiving naproxen developed gastric ulcers. In the platelet effects trial, no statistically significant difference from placebo was seen in the effect of celecoxib on platelet aggregation or bleeding time. In contrast, naproxen caused statistically significant reductions in platelet aggregation and a statistically significant increase in bleeding time. These preliminary trials show that celecoxib achieves analgesic and antiinflammatory efficacy in arthritis through specific COX-2 inhibition without showing evidence of two of the toxic effects of COX-1 inhibition associated with NSAID.
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PMID:Update on clinical developments with celecoxib, a new specific COX-2 inhibitor: what can we expect? 1022 38

Acute cholecystitis is associated with increased gallbladder prostanoid formation and the inflammatory changes and prostanoid increases can be inhibited by nonsteroidal anti-inflammatory agents. Recent information indicates that prostanoids are produced by two cyclooxygenase (COX) enzymes, COX-1 and COX-2. The purpose of this study was to determine the COX enzymatic pathway in gallbladder mucosal cells involved in the production of prostanoids stimulated by inflammatory agents. Human gallbladder mucosal cells were isolated from cholecystectomy specimens and maintained in cell culture and studied in comparison with cells from a well differentiated gallbladder mucosal carcinoma cell line. COX enzymes were evaluated by Western immunoblotting and prostanoids were measured by ELISA. Unstimulated and stimulated cells were exposed to specific COX-1 and COX-2 inhibitors. In both normal and transformed cells constitutive COX-1 was evident and in gallbladder cancer cells lysophosphatidyl choline (LPC) induced the formation of constitutive COX-1 enzyme. While not detected in unstimulated normal mucosal cells and cancer cells, COX-2 protein was induced by both lipopolysaccharide (LPS) and LPC. Unstimulated gallbladder mucosal cells and cancer cells produced prostaglandin E2 (PGE2) and prostacyclin (6-keto prostaglandin F1alpha, 6-keto PGF1alpha) continuously. In freshly isolated normal gallbladder mucosal cells, continuously produced 6 keto PGF1alpha was inhibited by both COX-1 and COX-2 inhibitors while PGE2 levels were not affected. Both LPS and LPC stimulated PGE2 and 6 keto PGF1alpha formation were blocked by COX-2 inhibitors in freshly isolated, normal human gallbladder mucosal cells and in the gallbladder cancer cells. The prostanoid response of gallbladder cells stimulated by proinflammatory agents is inhibited by COX-2 inhibitors suggesting that these agents may be effective in treating the pain and inflammation of gallbladder disease.
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PMID:Synthetic pathways of gallbladder mucosal prostanoids: the role of cyclooxygenase-1 and 2. 1032 26

Prostaglandins are formed from arachidonic acid by the action of cyclooxygenase (COX) and subsequent downstream synthetases. Recently, it has been found that there are two closely related forms of COX, which are now known as COX-1 and COX-2. Although both isoforms of this enzyme convert arachidonate to prostaglandins, there are significant differences in their distribution in the body and their roles in health and disease. The basis for these important differences lies in the genes for COX-1 and COX-2 and the regulation of these genes. COX-1, the predominantly constitutive form of the enzyme, is expressed throughout the body and provides certain homeostatic functions, such as maintaining normal gastric mucosa, influencing renal blood flow, and aiding in blood clotting by abetting platelet aggregation. In contrast, COX-2, the inducible form, is expressed in response to inflammatory and other physiologic stimuli and growth factors and is involved in the production of those prostaglandins that mediate pain and support the inflammatory process. All conventional nonsteroidal anti-inflammatory drugs (NSAIDs) nonspecifically inhibit both COX-1 and COX-2 at standard anti-inflammatory doses. The beneficial anti-inflammatory and analgesic effects occur through the inhibition of COX-2, but the gastrointestinal toxicities and the mild bleeding diathesis occur as a result of concurrent inhibition of COX-1. It is important that physicians fully understand the pharmacologic basis for the differential actions of NSAIDs when prescribing them for pain and inflammation. This understanding is also important so that physicians can critically evaluate the basis for, and the emerging data on, COX-2-specific inhibitors and their potential role in clinical medicine. Agents that would inhibit COX-2 while sparing COX-1 represent an attractive therapeutic development and could represent a major advance in the treatment of rheumatoid arthritis and osteoarthritis, as well as a diverse array of other conditions.
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PMID:Role and regulation of cyclooxygenase-2 during inflammation. 1039 Jan 26

Behavioral models indicate that persistent small afferent input, as generated by tissue injury, results in a hyperalgesia at the site of injury and a tactile allodynia in areas adjacent to the injury site. Hyperalgesia reflects a sensitization of the peripheral terminal and a central facilitation evoked by the persistent small afferent input. The allodynia reflects a central sensitization. The spinal pharmacology of these pain states has been defined in the unanesthetized rat prepared with spinal catheters for injection and dialysis. After tissue injury, excitatory transmitters (e.g., glutamate and substance P) acting though N-methyl-D-aspartate (NMDA) and neurokinin 1 receptors initiate a cascade that evokes release of (i) NO, (ii) cyclooxygenase products, and (iii) activation of several kinases. Spinal dialysis show amino acid and prostanoid release after cutaneous injury. Spinal neurokinin 1, NMDA, and non-NMDA receptors enhance spinal prostaglandin E2 release. Spinal prostaglandins facilitate release of spinal amino acids and peptides. Activation by intrathecal injection of receptors on spinal C fiber terminals (mu,/delta opiate, alpha2 adrenergic, neuropeptide Y) prevents release of primary afferent peptides and spinal amino acids and blocks acute and facilitated pain states. Conversely, consistent with their role in facilitated processing, NMDA, cyclooxygenase 2, and NO synthase inhibitors act to diminish only hyperalgesia. Importantly, spinal delivery of several of these agents diminishes human injury pain states. This efficacy emphasizes (i) the role of facilitated states in humans, (ii) shows the importance of spinal systems in human pain processing, and (iii) indicates that these preclinical mechanisms reflect processes that regulate the human pain experience.
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PMID:The spinal biology in humans and animals of pain states generated by persistent small afferent input. 1039 80

Nonsteroidal anti-inflammatory drugs (NSAIDs) are currently among the most widely prescribed drugs worldwide. Their therapeutic benefits and their side effects in the gastrointestinal tract and kidney, as well as in hemostasis, are of great importance in modern medicine. Within the past decade, new insights into how NSAIDs produce both their therapeutic benefits and their serious side effects have been discovered. It is now known that there are two froms of the cyclooxygenase (COX) enzyme that metabolize arachidonic acid into prostaglandins. Drugs that specifically inhibit the COX-2 enzyme were formulated and put into clinical trials during the past 5 years. These drugs are now available to treat patients in the United States. Specific COX-2 inhibitors offer the benefit of being able to treat the pain and inflammation of arthritis with potentially little risk of serious gastrointestinal injury.
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PMID:Specific cyclooxygenase-2 (COX-2) inhibitors. 1040 14

Several currently available nonsteroidal anti-inflammatory drugs (NSAIDs) have been evaluated for their relative selectivity in inhibiting the two cyclooxygenase (COX) isozymes, COX-1 and COX-2. Arguments have been made that more selective inhibitors of COX-2 will be safer than less selective ones. Rankings of the COX-2/COX-1 inhibition ratios of various NSAIDs as they relate to the agents' toxicities have been used as evidence that COX-2 selectivity is an important factor in the upper gastrointestinal (GI) safety of some NSAIDs. Unfortunately, none of these claims has been supported by endoscopy studies in treated patients. Since all NSAIDs inhibit COX-1, they all cause upper GI mucosal damage. What is needed are specific COX-2 inhibitors that do not inhibit COX-1. Such agents are currently under development. Ongoing clinical trials will determine the potential role for specific COX-2 inhibitors in the treatment of arthritis and pain. If specific COX-2 inhibitors are shown to be both safe and effective, the treatment of rheumatic diseases will be revolutionized.
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PMID:COX-2: separating myth from reality. 1042 43

Nonsteroidal anti-inflammatory drugs (NSAIDs) are effective for the relief of pain and inflammation, yet their use is tempered by the development of side effects, primarily in the gastrointestinal (GI) tract. It is now known that inhibition of the enzyme cyclooxygenase (COX) is the principal mechanism for both the efficacy and the toxicity of NSAIDs. Recent research has shown that COX exists as at least two isoenzymes, COX-1 and COX-2. Compelling evidence suggests that COX-1 synthesizes prostaglandins that are involved in the regulation of normal cell activity (including GI cytoprotection), whereas COX-2 appears to produce prostaglandins mainly at sites of inflammation. These findings led to the search for compounds that would inhibit COX-2 without affecting COX-1. Several agents are under investigation in this new therapeutic category, including celecoxib (SC-58635). Celecoxib was developed as an anti-inflammatory and analgesic agent, and has been studied in preclinical studies and in clinical trials. This paper focuses on the results of five key clinical trials of celecoxib: an efficacy trial in dental pain, a 2-week osteoarthritis (OA) efficacy trial, a 4-week rheumatoid arthritis (RA) efficacy trial, a 1-week endoscopic study of GI mucosal effects, and a 10-day study of effects on platelet function. The arthritis trials identified celecoxib doses that were effective in treating OA and RA and that were distinguished from placebo on standard arthritis scales. In the upper GI endoscopy study, no ulcers occurred in subjects receiving celecoxib or placebo, whereas 19% of subjects receiving naproxen developed gastric ulcers. In the platelet effects trial, no statistically significant difference from placebo was seen in the effect of celecoxib on platelet aggregation or bleeding time. In contrast, naproxen caused statistically significant reductions in platelet aggregation and a statistically significant increase in bleeding time. These preliminary trials show that celecoxib achieves analgesic and anti-inflammatory efficacy in arthritis through specific COX-2 inhibition without showing evidence of two of the toxic effects of COX-1 inhibition associated with NSAIDs.
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PMID:Update on clinical developments with celecoxib, a new specific COX-2 inhibitor: what can we expect? 1042 44


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