RESUMEN
BACKGROUND AND OBJECTIVE: Tylerdipine hydrochloride (KBP-5660) is a novel L/T-type dual calcium channel blocker developed for the treatment of hypertension. We aimed to study the pharmacokinetics, safety and tolerability of tylerdipine in healthy Chinese subjects. METHODS: Two double-blind, randomized, dose-escalation studies were conducted that included a total of 88 healthy subjects: (1) a single-ascending dose (SAD) study; and (2) a multiple-ascending dose (MAD) study. In the SAD study, 64 subjects were randomly assigned to receive a single dose of 0.5, 2.5, 5, 10, 15, 20, 25, or 30 mg of tylerdipine or placebo. In the MAD study, 24 subjects were randomly assigned to receive 10 or 20 mg of tylerdipine or placebo once daily for 9 days. Blood samples were collected at the designated time points for pharmacokinetic analyses. Safety assessments were conducted throughout the study. RESULTS: Following a single oral dose of tylerdipine of 5-30 mg, the mean maximum plasma concentration (Cmax) increased from 0.9993 to 10.11 ng/ml; mean area under the plasma-concentration curve (AUC) from time zero to 72 h increased from 4.332 to 73.95 h·ng/ml. AUC increased in a greater than dose-proportional manner, whereas Cmax exhibited a rough but non-typical dose-proportionality increase. In the MAD study, steady-state conditions were achieved after 1 week of daily dosing in both dose groups. Accumulation of tylerdipine was low, with accumulation ratios (RAUC) of less than 1.65. All adverse events were assessed as mild or moderate. CONCLUSION: Tylerdipine hydrochloride was safe and well tolerated. The exposure (AUC) of tylerdipine over the dose range of 5-30 mg increased in a greater than dose-proportional manner, while Cmax exhibited a rough but non-typical dose proportionality increase. A slight accumulation of tylerdipine was observed following multiple dosing. STUDY REGISTRATIONS: CTR20140862 and CTR20150660.
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Bloqueadores de los Canales de Calcio/administración & dosificación , Nitrobencenos/administración & dosificación , Adulto , Área Bajo la Curva , Pueblo Asiatico , Bloqueadores de los Canales de Calcio/efectos adversos , Bloqueadores de los Canales de Calcio/farmacocinética , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Femenino , Humanos , Masculino , Nitrobencenos/efectos adversos , Nitrobencenos/farmacocinética , Adulto JovenRESUMEN
This investigation aimed to study the in vivo harmful effects of the subcutaneous injection of different methicillin resistance Staphylococcus aureus extracts (MRSA2, MRSA4, MRSA10, MRSA69, MRSA70, MRSA76, and MRSA78). Such strains represented the highest minimum inhibition concentration toward methicillin with various multidrug-resistant patterns. The obtained results revealed that rats injected with the MRSA4 extract died immediately after the last dose indicating the high cytotoxicity of MRSA4 strain (100% mortality). While the mortalities in other groups injected by the other MRSA extracts ranged from 50 to 75%. In comparison with the normal animal group, all MRSA extracts induced a hepatotoxic effect which was indicated from the significant (p < 0.01) increases in the activities of the serum alanine aminotransferase (ALAT) and aspartate aminotransferase (ASAT) enzymes. Moreover, alkaline phosphatase (ALP) combined with a partial nephrotoxicity that was monitored from the significant elevation of serum urea concentration. While serum creatinine levels did not affect. Similarly, a significant elevation was recorded in serum levels of tumor biomarkers (alpha fetoprotein; AFP, carcinoembryonic antigen; CEA, and lactate dehydrogenase; LDH) reflecting their carcinogenic potential. On the other hand, the percentage of micronuclei (MN) in polychromatic erythrocytes from bone marrow cells was statistically significant in all groups as compared to the control group. The percentage of sperm abnormalities was statistically significant compared to the control. Different types of head abnormalities and coiled tail were recorded. Consequently, the current study focused on fighting MRSA virulence factors by the new compound ayamycin, which proved to be potent anti-virulence factor against all MRSA strains under study by significant decreasing of their streptokinase activities, hemolysin synthesis, biofilm formation, and their cell surface hydrophobicity.
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Carcinogénesis , Hexanonas/farmacología , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/fisiología , Nitrobencenos/farmacología , Espermatozoides/microbiología , Animales , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Relación Dosis-Respuesta a Droga , Células HeLa , Proteínas Hemolisinas/biosíntesis , Hexanonas/efectos adversos , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Riñón/microbiología , Hígado/microbiología , Masculino , Staphylococcus aureus Resistente a Meticilina/citología , Staphylococcus aureus Resistente a Meticilina/metabolismo , Nitrobencenos/efectos adversos , Ratas , Ratas Sprague-Dawley , Seguridad , Estreptoquinasa/metabolismo , Virulencia/efectos de los fármacosRESUMEN
Pyrosequencing and metagenomic profiling were used to assess the phylogenetic and functional characteristics of microbial communities residing in sediments collected from the estuaries of Rivers Oujiang (OS) and Jiaojiang (JS) in the western region of the East China Sea. Another sediment sample was obtained from near the shore far from estuaries, used for contrast (CS). Characterization of estuary sediment bacterial communities showed that toxic chemicals potentially reduced the natural variability in microbial communities, while they increased the microbial metabolic enzymes and pathways. Polycyclic aromatic hydrocarbons (PAHs) and nitrobenzene were negatively correlated with the bacterial community variation. The dominant class in the sediments was Gammaproteobacteria. According to Kyoto Encyclopedia of Genes and Genomes (KEGG) enzyme profiles, dominant enzymes were found in estuarine sediments, which increased greatly, such as 2-oxoglutarate synthase, acetolactate synthase, inorganic diphosphatase, and aconitate hydratase. In KEGG pathway profiles, most of the pathways were also dominated by specific metabolism in these sediments and showed a marked increase, for instance alanine, aspartate, and glutamate metabolism, carbon fixation pathways in prokaryotes, and aminoacyl-tRNA biosynthesis. The estuarine sediment bacterial diversity varied with the polluted river water inputs. In the estuary receiving river water from the more seriously polluted River Oujiang, the sediment bacterial community function was more severely affected.
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Bacterias/clasificación , Bacterias/genética , Estuarios , Sedimentos Geológicos/microbiología , Metagenómica/métodos , Consorcios Microbianos/genética , Ríos/microbiología , Contaminantes Químicos del Agua/análisis , Acetolactato Sintasa/metabolismo , Aconitato Hidratasa/metabolismo , Aminoácidos/metabolismo , Bacterias/enzimología , Bacterias/metabolismo , Secuencia de Bases , Ciclo del Carbono , China , Agua Dulce , Sedimentos Geológicos/química , Cetona Oxidorreductasas/metabolismo , Redes y Vías Metabólicas , Consorcios Microbianos/efectos de los fármacos , Nitrobencenos/efectos adversos , Filogenia , Hidrocarburos Policíclicos Aromáticos/efectos adversos , ARN Ribosómico 16S/genética , Salinidad , Análisis de Secuencia , Contaminantes Químicos del Agua/químicaRESUMEN
para-Chloronitrobenzene (p-CNB) is one of the important chemicals with high liposolubility and oxidizing properties. Heated p-CNB liquid can cause thermal injury by absorption over skin and wound and even methemoglobinemia by conversion of hemoglobin into methemoglobin. Severe methemoglobinemia is a life-threatening condition that demands immediate treatment. It is very rare for individuals to be injured by heated p-CNB, but they should be carefully attended to because of the peculiarities of this kind of injury. In the past 10 years, we received 5 patients who were injured by heated p-CNB. In addition to the intravenous administration of methylene blue, prompt and thorough wound management played a crucial role in the treatment of these critically ill patients, indicating the potential value of sufficient information for the clinical practitioners. The purpose of this article is to report our experience in the management of patients with thermal burns and p-CNB poisoning.
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Quemaduras Químicas , Desbridamiento/métodos , Metahemoglobinemia , Azul de Metileno/administración & dosificación , Nitrobencenos , Úlcera Cutánea , Adulto , Quemaduras Químicas/complicaciones , Quemaduras Químicas/diagnóstico , Quemaduras Químicas/etiología , Quemaduras Químicas/terapia , Enfermedad Crítica/terapia , Manejo de la Enfermedad , Intervención Médica Temprana/métodos , Inhibidores Enzimáticos/administración & dosificación , Humanos , Masculino , Metahemoglobinemia/diagnóstico , Metahemoglobinemia/etiología , Metahemoglobinemia/terapia , Persona de Mediana Edad , Nitrobencenos/efectos adversos , Nitrobencenos/metabolismo , Úlcera Cutánea/diagnóstico , Úlcera Cutánea/etiología , Úlcera Cutánea/cirugía , Resultado del TratamientoRESUMEN
BACKGROUND: An earlier investigation found increased bladder cancer incidence among workers at a rubber chemical manufacturing plant that used o-toluidine, aniline and nitrobenzene. The cohort was expanded to include additional workers (n=1875) and updated through 2007 to assess bladder cancer with improved exposure characterisation. METHODS: Work histories were updated and exposure categories and ranks were developed for o-toluidine, aniline and nitrobenzene combined. Incident cancers were identified by linkage to six state cancer registries. Residency in time-dependent cancer registry catchment areas was determined. SIR and standardised rate ratios for bladder cancer were calculated by exposure category and cumulative rank quartiles for different lag periods. Cox regression was used to model bladder cancer incidence with estimated cumulative rank, adjusting for confounders. Indirect methods were used to control for smoking. RESULTS: Excess bladder cancer was observed compared to the New York State population (SIR=2.87, 95% CI 2.02 to 3.96), with higher elevations among workers definitely exposed (moderate/high) (SIR=3.90, 95% CI 2.57 to 5.68), and in the highest cumulative rank quartile (SIR=6.13, 95% CI 2.80 to 11.6, 10-year lag). Bladder cancer rates increased significantly with estimated cumulative rank (10-year lag). Smoking only accounted for an estimated 8% elevation in bladder cancer incidence. CONCLUSIONS: Bladder cancer incidence remains elevated in this cohort and significantly associated with estimated cumulative exposure. Results are consistent with earlier findings in this and other cohorts. Despite other concurrent chemical exposures, we consider o-toluidine most likely responsible for the bladder cancer incidence elevation and recommend a re-examination of occupational exposure limits.
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Industria Química , Nitrobencenos/efectos adversos , Enfermedades Profesionales/inducido químicamente , Exposición Profesional/efectos adversos , Goma , Toluidinas/efectos adversos , Neoplasias de la Vejiga Urinaria/inducido químicamente , Adulto , Anciano , Anciano de 80 o más Años , Compuestos de Anilina/efectos adversos , Estudios de Cohortes , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , New York/epidemiología , Enfermedades Profesionales/epidemiología , Enfermedades Profesionales/etiología , Modelos de Riesgos Proporcionales , Fumar/efectos adversos , Neoplasias de la Vejiga Urinaria/epidemiología , Neoplasias de la Vejiga Urinaria/etiología , Adulto JovenRESUMEN
Nitrobenzene (NB) has become an important pollutant in the environment, but its potential effects on non-target species such as drake remain unknown. In this study, we investigated the oxidative stress response, the CYP450 system and histopathological changes of the liver of NB-treated drakes for 40 d. Our results indicated that NB induced significant changes in antioxidant enzyme (SOD, CAT and GSH-Px) activities and the MDA content in the liver of the drakes. NB caused a condition-dependent increase in APND, EROD and ECOD isoenzyme activities and CYP450 content with increased exposure dose. Significant histological alternations were observed in the liver of NB-treated drakes and the pathological changes revealed tissue damage that was more severe with increasing of exposure dose. To our knowledge, this is the first study to report the chronic effects of NB on oxidative stress, the CYP450 system and histopathology in the drakes. These significant effects caused by NB reveal that these indices can be used as biomarker for monitoring NB as an environmental pollutant. Thus, future studies are needed to fully understand the exact mechanisms of these findings.
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Sistema Enzimático del Citocromo P-450/efectos de los fármacos , Hígado/efectos de los fármacos , Nitrobencenos/efectos adversos , Animales , Antioxidantes/análisis , Sistema Enzimático del Citocromo P-450/análisis , Patos , Isoenzimas , Hígado/química , Hígado/patología , Masculino , Microsomas Hepáticos/química , Estrés Oxidativo/efectos de los fármacosRESUMEN
BACKGROUND: The effects of glucocorticoids on viral myocarditis are contentious. The aim of the present study was to determine whether there is a "window of opportunity" for glucocorticoid treatment in a mouse model of acute viral myocarditis induced by Coxsackie group B3 virus (CVB3). METHODS: A/J (H-2a) mice were randomly assigned to one of four experimental groups: (1) viral infection without dexamethasone (DEX) treatment; (2) treatment with 0.75mg/kg, i.p., DEX each day for 5 days prior to viral infection; (3) 0.75mg/kg, i.p., DEX treatment for 5 days immediately after viral infection; and (4) 0.75mg/kg, i.p., DEX treatment for 5 days starting on day 7 after infection. RESULTS: DEX administration before or immediately after viral infection improved survival and attenuated left ventricular dilatation, systolic dysfunction, fibrosis, and infiltration of immune cells in the post-infectious heart. In contrast, late administration of DEX reduced survival (as determined on day 14), and was associated with sustained increases in cardiac tumor necrosis factor-α and interferon-γ levels. The beneficial effects of early DEX administration on survival were completely abrogated by coadministration of a selective cyclooxygenase (COX)-2 inhibitor (NS-398; 5mg/kg per day, p.o.). Notably, the virus titer in the post-infectious heart was significantly suppressed by DEX, but coadministration of NS-398 at the time of viral infection abolished the suppressive effects of DEX and, in fact, increased virus titers. CONCLUSIONS: Early administration of DEX is beneficial in the treatment of fulminant viral myocarditis, whereas late administration of DEX is harmful. The beneficial effects of DEX on survival were completely abolished by simultaneous administration of a selective COX-2 inhibitor. Hence, we speculate that a direct action of DEX on cardiomyocytes, rather than anti-inflammatory effects of DEX on immune cells, confers resistance to myocardial damage induced by viral infection.
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Infecciones por Coxsackievirus , Dexametasona/administración & dosificación , Enterovirus Humano B , Glucocorticoides/administración & dosificación , Miocarditis/virología , Enfermedad Aguda , Animales , Inhibidores de la Ciclooxigenasa/efectos adversos , Modelos Animales de Enfermedad , Masculino , Ratones , Ratones Endogámicos , Nitrobencenos/efectos adversos , Sulfonamidas/efectos adversos , Factores de TiempoRESUMEN
Cyclooxygenase (COX)-2 is among the endothelial genes upregulated by uniform laminar shear stress (LSS), characteristically associated with atherosclerotic lesion-protected areas. We have addressed whether the induction of COX-2-dependent prostanoids in endothelial cells by LSS plays a role in restraining endothelial tumor necrosis factor (TNF)-alpha generation, a proatherogenic cytokine, through the induction of heme oxygenase-1 (HO)-1, an antioxidant enzyme. In human umbilical vein endothelial cells (HUVECs) exposed to steady LSS of 10 dyn/cm(2) for 6 hours, COX-2 protein was significantly induced, whereas COX-1 and the downstream synthases were not significantly modulated. This was associated with significant (P<0.05) increase of 6-keto-prostaglandin (PG)F(1alpha) (the hydrolysis product of prostacyclin), PGE(2), and PGD(2). In contrast, TNF-alpha released in the medium in 6 hours (3633+/-882 pg) or detected in cells lysates (1091+/-270 pg) was significantly (P<0.05) reduced versus static condition (9100+/-2158 and 2208+/-300 pg, respectively). Coincident induction of HO-1 was detected. The finding that LSS-dependent reduction of TNF-alpha generation and HO-1 induction were abrogated by the selective inhibitor of COX-2 NS-398, the nonselective COX inhibitor aspirin, or the specific prostacyclin receptor (IP) antagonist RO3244794 illuminates the central role played by LSS-induced COX-2-dependent prostacyclin in restraining endothelial inflammation. Carbacyclin, an agonist of IP, induced HO-1. Similarly to inhibition of prostacyclin biosynthesis or activity, the novel imidazole-based HO-1 inhibitor QC15 reversed TNF-alpha reduction by LSS. These findings suggest that inhibition of COX-2-dependent prostacyclin might contribute to acceleration of atherogenesis in patients taking traditional nonsteroidal antiinflammatory drugs (NSAIDs) and NSAIDs selective for COX-2 through downregulation of HO-1, which halts TNF-alpha generation in human endothelial cells.
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Aterosclerosis/enzimología , Ciclooxigenasa 2/metabolismo , Células Endoteliales/enzimología , Epoprostenol/metabolismo , Hemo-Oxigenasa 1/metabolismo , Inflamación/enzimología , Factor de Necrosis Tumoral alfa/biosíntesis , 6-Cetoprostaglandina F1 alfa , Aspirina/efectos adversos , Aspirina/farmacología , Aterosclerosis/inducido químicamente , Benzofuranos/farmacología , Células Cultivadas , Ciclooxigenasa 1/metabolismo , Inhibidores de la Ciclooxigenasa/efectos adversos , Inhibidores de la Ciclooxigenasa/farmacología , Dinoprost/metabolismo , Dinoprostona/metabolismo , Regulación hacia Abajo , Células Endoteliales/efectos de los fármacos , Epoprostenol/análogos & derivados , Epoprostenol/farmacología , Humanos , Inflamación/inducido químicamente , Nitrobencenos/efectos adversos , Nitrobencenos/farmacología , Perfusión , Propionatos/farmacología , Prostaglandina D2/metabolismo , Receptores de Epoprostenol , Receptores de Prostaglandina/efectos de los fármacos , Receptores de Prostaglandina/metabolismo , Estrés Mecánico , Sulfonamidas/efectos adversos , Sulfonamidas/farmacología , Regulación hacia ArribaRESUMEN
Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenases (COX) and are widely used for post-trauma musculoskeletal analgesia. In animal models, NSAIDs have been reported to delay fracture healing and cause non-union, possibly due to the drug-induced inhibition of osteoblast recruitment and differentiation. To further investigate the cellular effects of these drugs in the context of bone healing, we examined the effects of COX-1 inhibitor indomethacin and COX-2 inhibitors, parecoxib and NS398 on osteoclast and osteoblast differentiation and activity in vitro. We discovered that all tested COX-inhibitors significantly inhibited osteoclast differentiation, by 93%, 94% and 74% of control for 100 microM indomethacin, 100 microM parecoxib and 3 microM NS398, respectively. Furthermore, inhibition of COX-2 reduced also the resorption activity of mature osteoclasts. All tested COX-inhibitors also significantly inhibited osteoblast differentiation from human mesenchymal stem cells. Simultaneously, the number of adipocytes was significantly increased. The adipocyte covered areas in the cultures with 1 microM indomethacin, 1 microM parecoxib and 3 microM NS398 were 9%, 29% and 24%, respectively, as compared with 6% in the control group. This data suggests that COX-2 inhibition disturbs bone remodelling by inhibiting osteoclast differentiation and diverting stem cell differentiation towards adipocyte lineage instead of osteoblast lineage. In conclusion, our results further suggest cautious use of COX-2 inhibitors after osseous trauma.
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Adipocitos/efectos de los fármacos , Inhibidores de la Ciclooxigenasa/efectos adversos , Células Madre Mesenquimatosas/efectos de los fármacos , Osteoblastos/efectos de los fármacos , Osteoclastos/efectos de los fármacos , Adipocitos/citología , Animales , Bovinos , Diferenciación Celular/efectos de los fármacos , Linaje de la Célula , Células Cultivadas , Inhibidores de la Ciclooxigenasa 2/efectos adversos , Inhibidores de la Ciclooxigenasa 2/farmacología , Inhibidores de la Ciclooxigenasa/farmacología , Humanos , Técnicas In Vitro , Indometacina/efectos adversos , Indometacina/farmacología , Isoxazoles/efectos adversos , Isoxazoles/farmacología , Masculino , Células Madre Mesenquimatosas/citología , Ratones , Nitrobencenos/efectos adversos , Nitrobencenos/farmacología , Osteoblastos/citología , Osteoclastos/citología , Ratas , Ratas Sprague-Dawley , Sulfonamidas/efectos adversos , Sulfonamidas/farmacologíaRESUMEN
BACKGROUND AND OBJECTIVE: Simvastatin, a cholesterol-lowering drug, also stimulates oral bone growth when applied topically, without systemic side-effects. However, the mechanisms involved in vivo are not known. We hypothesized that bone morphogenetic protein-2, nitric oxide synthase, and cyclooxygenase-2 are involved, based on prior in vitro evidence. MATERIAL AND METHODS: A rat bilateral mandible model, where 0.5 mg of simvastatin in methylcellulose gel was placed on one side and gel alone on the other, was used to quantify nitric oxide, cyclooxygenase-2 and bone morphogenetic protein-2 (via tissue extraction, enzyme activity or immunoassay), and to analyze the bone formation rate (via undecalcified histomorphometry). Cyclooxygenase-2 and nitric oxide synthase inhibitors (NS-398 and L-NAME, respectively) were administered intraperitoneally. RESULTS: Simvastatin was found to stimulate local bone morphogenetic protein-2, nitric oxide and the regional bone formation rate (p < 0.05), whereas NS-398 inhibited bone morphogenetic protein-2 and reduced the bone formation rate (p < 0.05). CONCLUSION: These data suggest an association between simvastatin-induced bone morphogenetic protein-2 and bone formation in the mandibular microenvironment, and the negative effect of cyclooxygenase-2 inhibitors on bone growth.
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Anticolesterolemiantes/farmacología , Proteínas Morfogenéticas Óseas/metabolismo , Inhibidores de la Ciclooxigenasa 2/efectos adversos , Osteogénesis/efectos de los fármacos , Simvastatina/farmacología , Animales , Proteínas Morfogenéticas Óseas/efectos de los fármacos , Ciclooxigenasa 2/efectos de los fármacos , Ciclooxigenasa 2/metabolismo , Inhibidores Enzimáticos/administración & dosificación , Inhibidores Enzimáticos/efectos adversos , NG-Nitroarginina Metil Éster/administración & dosificación , NG-Nitroarginina Metil Éster/efectos adversos , Óxido Nítrico Sintasa/análisis , Óxido Nítrico Sintasa/efectos de los fármacos , Nitrobencenos/administración & dosificación , Nitrobencenos/efectos adversos , Ratas , Sulfonamidas/administración & dosificación , Sulfonamidas/efectos adversosRESUMEN
BACKGROUND: In the stomach, constitutive cyclooxygenase (COX-1) synthesizes prostaglandins that maintain the integrity of the gastric mucosa, while their inhibition contributes to gastric mucosal damage. In contrast COX-2, an inducible enzyme, forms prostanoids involved in pain and inflammation. AIM: To compare prostaglandin synthesis inhibition by meloxicam, a selective COX-2 NSAID reported to have better gastric tolerability, with indomethacin and NS-398 in human gastric mucosa and in whole blood assays. METHODS: Meloxicam, indomethacin or NS-398 were incubated with fresh human gastric mucosa pieces (100 mg in 1 mL phosphate buffered saline, pH 7.4, 37 degrees C, 30 min), clotting human blood (1 mL, 37 degrees C, 60 min) or with lipopolysaccharide-stimulated heparinized blood (1 mL, 37 degrees C, 24 h). Prostanoids were analysed by radioimmunoassay. RESULTS: Meloxicam was a less potent inhibitor of gastric mucosal eicosanoid compared to indomethacin, showing a sixfold difference in IC50 with gastric mucosal prostaglandin E (PGE) (11.8 and 1.8 microM, respectively). In the whole blood assays, the COX-2/COX-1 ratio for meloxicam was 0.2 compared to 0.9 for indomethacin confirming meloxicam's COX-2 selectivity. CONCLUSION: The results with human mucosa pieces would suggest that the better gastric tolerability of meloxicam compared to indomethacin is related to its relatively lower inhibition of gastric mucosal PGE synthesis by COX-1.
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Antiinflamatorios no Esteroideos/farmacología , Eicosanoides/biosíntesis , Indometacina/farmacología , Nitrobencenos/farmacología , Sulfonamidas/farmacología , Tiazinas/farmacología , Tiazoles/farmacología , Antiinflamatorios no Esteroideos/efectos adversos , Técnicas de Cultivo , Ciclooxigenasa 1 , Humanos , Indometacina/efectos adversos , Mucosa Intestinal/efectos de los fármacos , Mucosa Intestinal/patología , Mucosa Intestinal/fisiología , Isoenzimas/metabolismo , Meloxicam , Proteínas de la Membrana , Nitrobencenos/efectos adversos , Prostaglandina-Endoperóxido Sintasas/metabolismo , Prostaglandinas/biosíntesis , Sulfonamidas/efectos adversos , Tiazinas/efectos adversos , Tiazoles/efectos adversosRESUMEN
1. Effects of indomethacin, the selective cyclo-oxygenase (COX)-2 inhibitors NS-398 and DFU, and dexamethasone on gastric damage induced by 30 min ischaemia followed by 60 min reperfusion (I-R) were investigated in rats. Modulation of gastric levels of COX-1 and COX-2 mRNA by I-R was evaluated using Northern blot and reverse transcription-polymerase chain reaction. 2. I-R-induced gastric damage was dose-dependently aggravated by administration of indomethacin (1 - 10 mg kg(-1)), NS-398 (0.4 - 4 mg kg(-1)) or DFU (0.02 - 2 mg kg(-1)) as assessed macroscopically and histologically. 3. Likewise, administration of dexamethasone (1 mg kg(-1)) significantly increased I-R damage. 4. Low doses of 16, 16-dimethyl-prostaglandin(PG)E(2), that did not protect against ethanol-induced mucosal damage, reversed the effects of the selective COX-2 inhibitors, indomethacin and dexamethasone. 5. I-R had no effect on gastric COX-1 mRNA levels but increased COX-2 mRNA levels in a time-dependent manner. Dexamethasone inhibited the I-R-induced expression of COX-2 mRNA. 6. I-R was not associated with a measurable increase in gastric mucosal formation of 6-keto-PGF(1alpha) and PGE(2). PG formation was substantially inhibited by indomethacin (10 mg kg(-1)) but was not significantly reduced by NS-398 (4 mg kg(-1)), DFU (2 mg kg(-1)) or dexamethasone (1 mg kg(-1)). 7. The findings indicate that selective COX-2 inhibitors and dexamethasone markedly enhance gastric damage induced by I-R. Thus, whereas COX-2 has no essential role in the maintenance of gastric mucosal integrity under basal conditions, COX-2 is rapidly induced in a pro-ulcerogenic setting and contributes to mucosal defence by minimizing injury. This suggests that in certain situations selective COX-2 inhibitors may have gastrotoxic effects.
Asunto(s)
Inhibidores de la Ciclooxigenasa/efectos adversos , Furanos/efectos adversos , Indometacina/efectos adversos , Isoenzimas/farmacología , Nitrobencenos/efectos adversos , Prostaglandina-Endoperóxido Sintasas/farmacología , Daño por Reperfusión/inducido químicamente , Sulfonamidas/efectos adversos , Animales , Ciclooxigenasa 1 , Ciclooxigenasa 2 , Inhibidores de la Ciclooxigenasa 2 , Relación Dosis-Respuesta a Droga , Mucosa Gástrica/efectos de los fármacos , Isoenzimas/metabolismo , Masculino , Proteínas de la Membrana , Prostaglandina-Endoperóxido Sintasas/metabolismo , Prostaglandinas/uso terapéutico , ARN Mensajero/efectos de los fármacos , ARN Mensajero/metabolismo , Ratas , Ratas Wistar , Daño por Reperfusión/tratamiento farmacológicoRESUMEN
The molecular identification of a second isoform of cyclooxygenase-2 (COX-2) led to a major investment by several pharmaceutical companies in the development of selective inhibitors. The central tenets of the rationale for developing selective COX-2 inhibitors are that prostaglandins that contribute to inflammation are derived from COX-2, whereas prostaglandins that are involved in normal physiological processes are derived from the constitutively expressed isoform COX-1. There is now considerable evidence that COX-2 is actually expressed constitutively in many tissues and performs important physiological functions. Thus, suppression of COX-2 with selective inhibitors should not be expected to be without some adverse consequences. Moreover, there is strong evidence that COX-1 contributes to inflammation and pain, so selective inhibition of COX-2 will not necessarily produce the same degree of efficacy that is seen with mixed inhibitors of COX-1 and COX-2.
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Antiinflamatorios no Esteroideos/efectos adversos , Inhibidores de la Ciclooxigenasa/efectos adversos , Prostaglandina-Endoperóxido Sintasas/metabolismo , Celecoxib , Ensayos Clínicos Controlados como Asunto , Ciclooxigenasa 2 , Inhibidores de la Ciclooxigenasa 2 , Etodolaco/efectos adversos , Expresión Génica , Humanos , Ibuprofeno/efectos adversos , Indometacina/efectos adversos , Isoenzimas/antagonistas & inhibidores , Isoenzimas/metabolismo , Isoenzimas/farmacología , Meloxicam , Proteínas de la Membrana , Naproxeno/efectos adversos , Nitrobencenos/efectos adversos , Prostaglandina-Endoperóxido Sintasas/biosíntesis , Prostaglandina-Endoperóxido Sintasas/farmacología , Pirazoles , Sulfonamidas/efectos adversos , Tiazinas/efectos adversos , Tiazoles/efectos adversosAsunto(s)
Química Farmacéutica , Dermatitis Alérgica por Contacto/etiología , Dermatitis Profesional/etiología , Irritantes/efectos adversos , Personal de Laboratorio Clínico , Nitrobencenos/efectos adversos , Exposición Profesional/efectos adversos , Exposición Profesional/normas , Adulto , Femenino , HumanosRESUMEN
Effects of the selective cyclooxygenase-2 (COX-2) inhibitors such as NS-398 and nimesulide on duodenal HCO3- secretory and ulcerogenic responses to mucosal acidification were examined in rats, in comparison with indomethacin, a nonselective COX inhibitor. Duodenal HCO3- secretion in anesthetized rats was increased in response to mucosal acidification. The increased HCO3- response to acid was significantly suppressed by pretreatment with indomethacin (10 mg kg(-1), s.c.), while both NS-398 and nimesulide (10 mg kg(-1), s.c.) had no effect on this response. The luminal release of prostaglandin E2 (PGE2) was increased during and after mucosal acidification, and this response was significantly inhibited by indomethacin but not NS-398 or nimesulide. Indomethacin provoked hemorrhagic lesions in the duodenum when acid hypersecretion was concomitantly induced by histamine (8 mg kg(-1) hr(-1), i.v.), while either NS-398 or nimesulide did not cause damage in the duodenum. Either of these drugs had no effect on histamine-induced acid secretion. On the other hand, both NS-398 and nimesulide showed a significant suppression against carrageenan-induced rat paw edema, similar to indomethacin. The present study supports a mediator role for endogenous PGs in duodenal HCO3- secretion in response to mucosal acidification and suggests that COX-1 but not COX-2 is a key enzyme in regulating this process and maintaining the mucosal integrity against acid in the duodenum.
Asunto(s)
Antiinflamatorios no Esteroideos/efectos adversos , Bicarbonatos/metabolismo , Inhibidores de la Ciclooxigenasa/efectos adversos , Úlcera Duodenal/inducido químicamente , Duodeno/fisiopatología , Ácido Gástrico/metabolismo , Animales , Dinoprostona/metabolismo , Úlcera Duodenal/fisiopatología , Duodeno/efectos de los fármacos , Histamina/farmacología , Concentración de Iones de Hidrógeno , Indometacina/efectos adversos , Mucosa Intestinal/fisiopatología , Masculino , Nitrobencenos/efectos adversos , Ratas , Ratas Sprague-Dawley , Sulfonamidas/efectos adversosRESUMEN
Two isoforms of cyclooxygenase (COX) are described: COX-1 is a constitutive enzyme and is widely expressed in most tissues, COX-2 is an inducible enzyme and is abundant throughout the gastrointestinal tract. Expression of COX-2 can be induced locally by inflammatory stimuli and appears coincident with local prostaglandin (PG) production. Currently available non-steroidal antiinflammatory drugs (NSAIDs) are widely used for the treatment of inflammatory diseases; however, significant side-effects due to inhibition of COX-1 limit their use. Inhibitors of COX-2 are as active as non-selective NSAIDs and inhibit PG synthesis in inflammatory cells. In contrast to other NSAIDs, selective COX-2 inhibitors do not cause ulcers in the stomach or intestine.