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Preoperative anemia is a common finding in patients undergoing colorectal surgery, particularly those with cancer. While often multifactorial, iron deficiency anemia remains the most common cause of anemia in this patient population. Although seemingly innocuous, preoperative anemia is associated with an increased risk of perioperative complications and need for allogenic blood transfusions, both of which may worsen cancer-specific survival. Preoperative correction of anemia and iron deficiency is thus necessary to diminish these risks. Current literature supports preoperative screening for anemia and iron deficiency in patients slated to undergo colorectal surgery for malignancy or for benign conditions with associated patient- or procedure-related risk factors. Accepted treatment regimens include iron supplementation-either oral or intravenous-as well as erythropoietin therapy. Autologous blood transfusion should not be utilized as a treatment for preoperative anemia when there is time to implement other corrective strategies. Additional study is still needed to better standardize preoperative screening and optimize treatment regimens.
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BACKGROUND: Immunogenicity of cancer vaccines is impacted by adjuvants and schedule, but systematic assessments of their effects have not been performed. Montanide ISA-51, an incomplete Freund's adjuvant (IFA), is used in many vaccine trials, but concerns have been raised about negative effects in murine studies. We found in humans that IFA enhances systemic immune responses and that repeat vaccination at one site (same site vaccination (SSV)) creates tertiary lymphoid structures (TLS) in the vaccine site microenvironment (VSME). We hypothesized that vaccination with peptides+IFA+pICLC or SSV×3 with peptides in IFA would create an immunogenic milieu locally at the VSME, with activated dendritic cells (DC), TLS-associated chemokines and a Th1-dominant VSME. METHODS: Biopsies of the VSME were obtained from participants on two clinical trials who were immunized with multiple melanoma peptides (MELITAC 12.1) in adjuvants comprising IFA and/or the TLR3-agonist pICLC. Biopsies were obtained either a week after one vaccine or a week after SSV×3. Controls included normal skin and skin injected with IFA without peptides. Gene expression analysis was performed by RNAseq. RESULTS: VSME samples were evaluated from 27 patients. One vaccine with peptides in pICLC+IFA enhanced expression of CD80, CD83, CD86 (p<0.01), CD40 and CD40L (p<0.0001) over normal skin; these effects were significantly enhanced for SSV with peptides+IFA. Vaccines containing pICLC increased expression of TBX21 (T-bet) but did not decrease GATA3 over normal skin, whereas SSV with peptides in IFA dramatically enhanced TBX21 and decreased GATA3, with high expression of IFNγ and STAT1. SSV with peptides in IFA also reduced arginase-1 (ARG1) expression and enhanced expression of TLR adapter molecules TICAM-1 (TRIF) and MYD88. Furthermore, SSV with IFA and peptides also enhanced expression of chemokines associated with TLS formation. CONCLUSIONS: These findings suggest that SSV with peptides in IFA enhances CD40L expression by CD4 T cells, supports a Th1 microenvironment, with accumulation of activated and mature DC. Increased expression of TLR adaptor proteins after SSV with peptides in IFA might implicate effects of the skin microbiome. Reduced ARG1 may reflect diminished suppressive myeloid activity in the VSME. TRIAL REGISTRATION NUMBER: (NCT00705640, NCT01585350).
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Adyuvantes Inmunológicos/administración & dosificación , Vacunas contra el Cáncer/administración & dosificación , Adyuvante de Freund/administración & dosificación , Lípidos/administración & dosificación , Melanoma/terapia , Neoplasias Cutáneas/terapia , Vacunación/métodos , Adulto , Anciano , Anciano de 80 o más Años , Antígenos de Neoplasias/inmunología , Arginasa/metabolismo , Biopsia , Linfocitos T CD4-Positivos/efectos de los fármacos , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Ligando de CD40/inmunología , Ligando de CD40/metabolismo , Vacunas contra el Cáncer/inmunología , Ensayos Clínicos Fase I como Asunto , Femenino , Adyuvante de Freund/inmunología , Humanos , Inmunización Secundaria/métodos , Inmunogenicidad Vacunal , Inyecciones Intralesiones , Lípidos/inmunología , Masculino , Manitol/administración & dosificación , Manitol/análogos & derivados , Manitol/inmunología , Melanoma/inmunología , Melanoma/patología , Persona de Mediana Edad , Ácidos Oléicos/administración & dosificación , Ácidos Oléicos/inmunología , Ensayos Clínicos Controlados Aleatorios como Asunto , Transducción de Señal/efectos de los fármacos , Transducción de Señal/inmunología , Piel/inmunología , Piel/patología , Neoplasias Cutáneas/inmunología , Neoplasias Cutáneas/patología , Células TH1/efectos de los fármacos , Células TH1/inmunología , Receptores Toll-Like/metabolismo , Microambiente Tumoral/inmunología , Vacunas de Subunidad/administración & dosificación , Vacunas de Subunidad/inmunología , Adulto JovenRESUMEN
Successful medicinal chemistry campaigns to discover and optimize sphingosine kinase inhibitors require a robust assay for screening chemical libraries and for determining rank order potencies. Existing assays for these enzymes are laborious, expensive and/or low throughput. The toxicity of excessive levels of phosphorylated sphingoid bases for the budding yeast, Saccharomyces cerevisiae, affords an assay wherein inhibitors added to the culture media rescue growth in a dose-dependent fashion. Herein, we describe our adaptation of a simple, inexpensive, and high throughput assay for assessing inhibitors of sphingosine kinase types 1 and 2 as well as ceramide kinase and for testing enzymatic activity of sphingosine kinase type 2 mutants. The assay was validated using recombinant enzymes and generally agrees with the rank order of potencies of existing inhibitors.
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Evaluación Preclínica de Medicamentos/métodos , Inhibidores Enzimáticos/farmacología , Fosfotransferasas (Aceptor de Grupo Alcohol)/antagonistas & inhibidores , Saccharomyces cerevisiae/enzimología , Animales , Ensayos Analíticos de Alto Rendimiento/métodos , Humanos , Metanol , Ratones , Mutación , Fosfotransferasas (Aceptor de Grupo Alcohol)/genética , Fosfotransferasas (Aceptor de Grupo Alcohol)/metabolismo , Pirrolidinas/farmacología , Saccharomyces cerevisiae/efectos de los fármacos , Saccharomyces cerevisiae/genética , Esfingolípidos/genética , Esfingolípidos/metabolismo , Sulfonas/farmacologíaRESUMEN
Myelodysplastic syndromes and chronic myelomonocytic leukemia are blood disorders characterized by ineffective hematopoiesis and progressive marrow failure that can transform into acute leukemia. The DNA methyltransferase inhibitor 5-azacytidine (AZA) is the most effective pharmacological option, but only â¼50% of patients respond. A response only manifests after many months of treatment and is transient. The reasons underlying AZA resistance are unknown, and few alternatives exist for non-responders. Here, we show that AZA responders have more hematopoietic progenitor cells (HPCs) in the cell cycle. Non-responder HPC quiescence is mediated by integrin α5 (ITGA5) signaling and their hematopoietic potential improved by combining AZA with an ITGA5 inhibitor. AZA response is associated with the induction of an inflammatory response in HPCs in vivo. By molecular bar coding and tracking individual clones, we found that, although AZA alters the sub-clonal contribution to different lineages, founder clones are not eliminated and continue to drive hematopoiesis even in complete responders.
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Azacitidina/administración & dosificación , Resistencia a Medicamentos , Genómica , Síndromes Mielodisplásicos , Anciano , Anciano de 80 o más Años , Resistencia a Medicamentos/efectos de los fármacos , Resistencia a Medicamentos/genética , Femenino , Humanos , Cadenas alfa de Integrinas/genética , Cadenas alfa de Integrinas/metabolismo , Persona de Mediana Edad , Síndromes Mielodisplásicos/tratamiento farmacológico , Síndromes Mielodisplásicos/genética , Síndromes Mielodisplásicos/metabolismoRESUMEN
We present a method to identify the dynamics of a human arm controlled by an implanted functional electrical stimulation neuroprosthesis. The method uses Gaussian process regression to predict shoulder and elbow torques given the shoulder and elbow joint positions and velocities and the electrical stimulation inputs to muscles. We compare the accuracy of torque predictions of nonparametric, semiparametric, and parametric model types. The most accurate of the three model types is a semiparametric Gaussian process model that combines the flexibility of a black box function approximator with the generalization power of a parameterized model. The semiparametric model predicted torques during stimulation of multiple muscles with errors less than 20% of the total muscle torque and passive torque needed to drive the arm. The identified model allows us to define an arbitrary reaching trajectory and approximately determine the muscle stimulations required to drive the arm along that trajectory.
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Brazo/fisiología , Terapia por Estimulación Eléctrica/métodos , Modelos Biológicos , Modelos Estadísticos , Contracción Muscular/fisiología , Músculo Esquelético/fisiología , Miembros Artificiales , Simulación por Computador , Terapia por Estimulación Eléctrica/instrumentación , Retroalimentación Fisiológica , Humanos , Músculo Esquelético/inervación , Rehabilitación Neurológica/instrumentación , Rehabilitación Neurológica/métodos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Terapia Asistida por Computador/instrumentación , Terapia Asistida por Computador/métodosRESUMEN
Sphingosine 1-phosphate (S1P), the natural sphingolipid ligand for a family of five G protein- coupled receptors (S1P1-S1P5Rs), regulates cell survival and lymphocyte circulation. We have shown that the pan-S1PR agonist, FTY720, attenuates kidney ischemia-reperfusion injury by directly activating S1P1 on proximal tubule (PT) cells, independent of the canonical lymphopenic effects of S1P1 activation on B and T cells. FTY720 also reduces cisplatin-induced AKI. Therefore, in this study, we used conditional PT-S1P1-null (PepckCreS1pr1(fl/fl)) and control (PepckCreS1pr1(w/wt)) mice to determine whether the protective effect of FTY720 in AKI is mediated by PT-S1P1. Cisplatin induced more renal injury in PT-S1P1-null mice than in controls. Although FTY720 produced lymphopenia in both control and PT-S1P1-null mice, it reduced injury only in control mice. Furthermore, the increase in proinflammatory cytokine (CXCL1, MCP-1, TNF-α, and IL-6) expression and infiltration of neutrophils and macrophages induced by cisplatin treatment was attenuated by FTY720 in control mice but not in PT-S1P1-null mice. Similarly, S1P1 deletion rendered cultured PT cells more susceptible to cisplatin-induced injury, whereas S1P1 overexpression protected PT cells from injury and preserved mitochondrial function. We conclude that S1P1 may have an important role in stabilizing mitochondrial function and that FTY720 administration represents a novel strategy in the prevention of cisplatin-induced AKI.
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Lesión Renal Aguda/prevención & control , Túbulos Renales Proximales/efectos de los fármacos , Mitocondrias/efectos de los fármacos , Glicoles de Propileno/uso terapéutico , Receptores de Lisoesfingolípidos/agonistas , Esfingosina/análogos & derivados , Lesión Renal Aguda/inducido químicamente , Animales , Apoptosis/efectos de los fármacos , Respiración de la Célula , Cisplatino , Evaluación Preclínica de Medicamentos , Células Epiteliales/efectos de los fármacos , Clorhidrato de Fingolimod , Masculino , Ratones Endogámicos C57BL , Dinámicas Mitocondriales , Glicoles de Propileno/farmacología , Receptores de Lisoesfingolípidos/metabolismo , Esfingosina/farmacología , Esfingosina/uso terapéuticoRESUMEN
OBJECTIVE: To study the influence of adjuvant androgen suppression and bisphosphonates on incident vertebral and non-spinal fracture rates and bone mineral density (BMD) in men with locally advanced prostate cancer. PATIENTS AND METHODS: Between 2003 and 2007, 1071 men with locally advanced prostate cancer were randomly allocated, using a 2 × 2 trial design, to 6 months i.m. leuprorelin (androgen suppression [AS]) before radiotherapy alone ± 12 months additional leuprorelin ± 18 months zoledronic acid (ZdA), commencing at randomization. The main endpoint was incident thoraco-lumbar vertebral fractures, which were assessed radiographically at randomization and at 3 years, then reassessed by centralized review. Subsidiary endpoints included incident non-spinal fractures, which were documented throughout follow-up, and BMD, which was measured in 222 subjects at baseline, 2 years and 4 years. RESULTS: Incident vertebral fractures at 3 years were observed in 132 subjects. Their occurrence was not increased by 18 months' AS, nor reduced by ZdA. Incident non-spinal fractures occurred in 72 subjects and were significantly related to AS duration but not to ZdA. Osteopenia and osteoporosis prevalence rates at baseline were 23.4 and 1.4%, respectively, at the hip. Treatment for 6 and 18 months with AS caused significant reductions in hip BMD at 2 and 4 years (P < 0.01) and ZdA prevented these losses at both time points. CONCLUSION: In an AS-naïve population, 18 months of ZdA treatment prevented the sustained BMD losses caused by 18 months of AS treatment; however, the study power was insufficient to show that AS duration or ZdA influenced vertebral fracture rates.
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Antagonistas de Andrógenos/efectos adversos , Antineoplásicos Hormonales/efectos adversos , Conservadores de la Densidad Ósea/uso terapéutico , Densidad Ósea/efectos de los fármacos , Difosfonatos/uso terapéutico , Imidazoles/uso terapéutico , Neoplasias de la Próstata/tratamiento farmacológico , Fracturas de la Columna Vertebral/inducido químicamente , Anciano , Anciano de 80 o más Años , Antagonistas de Andrógenos/administración & dosificación , Antineoplásicos Hormonales/administración & dosificación , Australia , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Nueva Zelanda , Neoplasias de la Próstata/patología , Fracturas de la Columna Vertebral/prevención & control , Resultado del Tratamiento , Ácido ZoledrónicoRESUMEN
A major challenge in controlling multiple-input multiple output functional electrical stimulation systems is the large amount of time required to identify a workable system model due to the high dimensionality of the space of inputs. To address this challenge we are exploring optimal methods to sample the input space. In this paper we present two methods for optimally sampling isometric muscle force recruitment curves. One method maximizes the information about the recruitment curve parameters, and the second method minimizes the average variance of the predicted output force. We compared these methods to two previously-used methods in simulation. The simulation model was identified from recruitment data collected during experiments with a human subject with a high spinal cord injury. The optimal sampling methods on average produced estimates of the output force with less error than the two previously-used methods. The optimal sampling methods require fewer system identification experiments to identify models with similar output prediction accuracy.
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Simulación por Computador , Terapia por Estimulación Eléctrica/métodos , Contracción Isométrica , Modelos Biológicos , Músculo Esquelético/fisiopatología , Traumatismos de la Médula Espinal , Bases de Datos Factuales , Humanos , Valor Predictivo de las Pruebas , Traumatismos de la Médula Espinal/fisiopatología , Traumatismos de la Médula Espinal/terapiaRESUMEN
Lysophosphatidic acid (LPA) is a simple lipid with many important biological functions such as the regulation of cellular proliferation, cellular migration, differentiation, and suppression of apoptosis. Although a direct angiogenic effect of LPA has not been reported to date, there are indications that LPA promotes angiogenesis. In addition, LPA is a chemoattractant for cultured endothelial cells and promotes barrier function in such cultures. To test the hypothesis that LPA is angiogenic, we used the chicken chorio-allantoic membrane (CAM) assay. Sequence analysis of the cloned, full-length chicken LPA receptor cDNAs revealed three receptor types that are orthologous to the mammalian LPA(1), LPA(2), and LPA(3) receptors. We document herein that LPA is angiogenic in the CAM system and further that synthetic LPA receptor agonists and antagonists mimic or block this response, respectively. Our results predict that LPA receptor antagonists are a possible therapeutic route to interdicting angiogenesis.
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Lisofosfolípidos/farmacología , Neovascularización Fisiológica/efectos de los fármacos , Receptores del Ácido Lisofosfatídico/fisiología , Secuencia de Aminoácidos , Inhibidores de la Angiogénesis/farmacología , Animales , Embrión de Pollo , Evaluación Preclínica de Medicamentos , Datos de Secuencia Molecular , Organofosfatos/farmacología , Piridinas/farmacología , Receptores del Ácido Lisofosfatídico/antagonistas & inhibidores , Homología de Secuencia de Aminoácido , Esfingosina/análogos & derivados , Esfingosina/farmacología , Especificidad por Sustrato , Factor A de Crecimiento Endotelial Vascular/farmacologíaRESUMEN
Marijuana users consistently demonstrate impairments in attention, executive function and response inhibition, which resemble deficits seen in attention deficit hyperactivity disorder (ADHD). We hypothesized that targeting the cognitive deficits associated with chronic marijuana use through ADHD medications may help identify a therapeutic agent for marijuana dependence. Thirteen subjects participated in an 11-week open label study to determine the feasibility, safety and tolerability of atomoxetine for individuals seeking treatment for marijuana dependence. The Time-Line Follow-Back measured marijuana use 90 days prior to study entry (p-TLFB) and weekly during the study (s-TLFB) along with weekly qualitative urine drug screen (UDS). For the eight subjects who completed the trial, the TLFB data showed a trend toward reduction in use with an increase in percent days abstinent (p=0.06). Analysis of weekly UDSs did not confirm the TLFB trend with 94% of all possible UDSs positive for THC through out the study. Marijuana dependent subjects taking atomoxetine experienced an inordinate number of gastrointestinal (GI) adverse events. Overall, 10 of 13 subjects (77%) experienced a mild to moderate GI adverse event defined as nausea, vomiting, dyspepsia, and loose stools. Atomoxetine is of limited utility in the treatment of cannabis dependence and is associated with clinically significant GI adverse events.
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Inhibidores de Captación Adrenérgica/efectos adversos , Enfermedades Gastrointestinales/inducido químicamente , Enfermedades Gastrointestinales/epidemiología , Abuso de Marihuana/rehabilitación , Propilaminas/efectos adversos , Inhibidores de Captación Adrenérgica/uso terapéutico , Adulto , Clorhidrato de Atomoxetina , Estudios de Factibilidad , Femenino , Humanos , Incidencia , Masculino , Proyectos Piloto , Propilaminas/uso terapéuticoRESUMEN
Envenomation by the brown recluse spider (Loxosceles reclusa) may cause local dermonecrosis and, rarely, coagulopathies, kidney failure and death. A venom phospholipase, SMaseD (sphingomyelinase D), is responsible for the pathological manifestations of envenomation. Recently, the recombinant SMaseD from Loxosceles laeta was demonstrated to hydrolyse LPC (lysophosphatidylcholine) to produce LPA (lysophosphatidic acid) and choline. Therefore activation of LPA signalling pathways may be involved in some manifestations of Loxosceles envenomation. To begin investigating this idea, we cloned a full-length cDNA encoding L. reclusa SMaseD. The 305 amino acid sequence of the L. reclusa enzyme is 87, 85 and 60% identical with those of L. arizonica, L. intermedia and L. laeta respectively. The recombinant enzyme expressed in bacteria had broad substrate specificity. The lysophospholipids LPC, LPI (18:1-1-oleyol lysophosphatidylinositol), LPS, LPG (18:1-1-oleoyl-lysophosphatidylglycerol), LBPA (18:1-1-oleoyl-lysobisphosphatidic acid) (all with various acyl chains), lyso-platelet-activating factor (C16:0), cyclic phosphatidic acid and sphingomyelin were hydrolysed, whereas sphingosylphosphorylcholine, PC (phosphatidylcholine; C22:6, C20:4 and C6:0), oxidized PCs and PAF (platelet-activating factor; C16:0) were not hydrolysed. The PAF analogue, edelfosine, inhibited enzyme activity. Recombinant enzyme plus LPC (C18:1) induced the migration of A2058 melanoma cells, and this activity was blocked by the LPA receptor antagonist, VPC32183. The recombinant spider enzyme was haemolytic, but this activity was absent from catalytically inactive H37N (His37-->Asn) and H73N mutants. Our results demonstrate that Loxosceles phospholipase D hydrolyses a wider range of lysophospholipids than previously supposed, and thus the term 'SMaseD' is too limited in describing this enzyme.
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Lisofosfolípidos/metabolismo , Fosfolipasa D/metabolismo , Hidrolasas Diéster Fosfóricas/metabolismo , Venenos de Araña/metabolismo , Arañas/enzimología , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Animales , Secuencia de Bases , Clonación Molecular , ADN Complementario/química , Regulación Enzimológica de la Expresión Génica , Datos de Secuencia Molecular , Mutación , Fosfolipasa D/antagonistas & inhibidores , Fosfolipasa D/química , Éteres Fosfolípidos , Mutación Puntual , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Arañas/metabolismo , Especificidad por SustratoRESUMEN
This article presents information on treatment services received by women participating in an initial multistate evaluation of CASAWORKS families. Results indicated most women received services to address medical, employment, basic needs, alcohol and drug, family, and psychiatric problems during the first six months of the program. The clients also had frequent contact with their case managers and were retained in the program for an average of 222 days. Considerable variation was observed across sites in the percentage of clients who received various services and the number of sessions they received. In Cox regressions, shorter retention in the program was predicted by referral to program from Child Protective Services or parole/probation, social conflicts, employment, and marijuana use at baseline, whereas a history of suicide attempts was associated with longer retention. Longer retention was associated with better alcohol use outcomes but was unrelated to employment or drug use outcomes.
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Servicios de Salud Mental/organización & administración , Servicio Social/organización & administración , Trastornos Relacionados con Sustancias/terapia , Servicios de Salud para Mujeres/organización & administración , Adulto , Manejo de Caso , Salud de la Familia , Femenino , Investigación sobre Servicios de Salud , Humanos , Proyectos Piloto , Desarrollo de Programa , Servicio Social/estadística & datos numéricos , Trastornos Relacionados con Sustancias/psicología , Estados UnidosRESUMEN
This prospective study involved 59 adolescents with drug and alcohol disorders who had just completed outpatient treatment. They participated in a comprehensive baseline assessment, and then participated in monthly telephone assessments of substance use and reasons for use. Despite their recent treatment, two-thirds (66%) of the participants in this study had relapsed to drug use within 6 months. The median time to drug relapse was only 54 days (+/-14 days), or slightly less than 2 months. The three most commonly given reasons for relapse were social pressure, withdrawal, and negative affect. These findings provide a first confirmation of the results of S.A. Brown [Recovery patterns in adolescent substance abuse. (1993). In J. S. Baer, G. A. Marlatt, & R. J. McMahon (Eds.), Addictive behaviors across the life span (pp. 160-183). London: SAGE.] in showing that most adolescents relapse quickly following treatment for substance use disorders.
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Conducta del Adolescente , Trastornos Relacionados con Sustancias/rehabilitación , Adolescente , Femenino , Humanos , Masculino , Estudios Prospectivos , Recurrencia , Análisis de Regresión , Trastornos Relacionados con Sustancias/prevención & controlRESUMEN
P2X3 and P2X2/3 receptors are highly localized on peripheral and central processes of sensory afferent nerves, and activation of these channels contributes to the pronociceptive effects of ATP. A-317491 is a novel non-nucleotide antagonist of P2X3 and P2X2/3 receptor activation. A-317491 potently blocked recombinant human and rat P2X3 and P2X2/3 receptor-mediated calcium flux (Ki = 22-92 nM) and was highly selective (IC50 >10 microM) over other P2 receptors and other neurotransmitter receptors, ion channels, and enzymes. A-317491 also blocked native P2X3 and P2X2/3 receptors in rat dorsal root ganglion neurons. Blockade of P2X3 containing channels was stereospecific because the R-enantiomer (A-317344) of A-317491 was significantly less active at P2X3 and P2X2/3 receptors. A-317491 dose-dependently (ED50 = 30 micromolkg s.c.) reduced complete Freund's adjuvant-induced thermal hyperalgesia in the rat. A-317491 was most potent (ED50 = 10-15 micromolkg s.c.) in attenuating both thermal hyperalgesia and mechanical allodynia after chronic nerve constriction injury. The R-enantiomer, A-317344, was inactive in these chronic pain models. Although active in chronic pain models, A-317491 was ineffective (ED50 >100 micromolkg s.c.) in reducing nociception in animal models of acute pain, postoperative pain, and visceral pain. The present data indicate that a potent and selective antagonist of P2X3 and P2X2/3 receptors effectively reduces both nerve injury and chronic inflammatory nociception, but P2X3 and P2X2/3 receptor activation may not be a major mediator of acute, acute inflammatory, or visceral pain.
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Analgésicos no Narcóticos/farmacología , Antiinflamatorios no Esteroideos/farmacología , Fenoles/farmacología , Compuestos Policíclicos/farmacología , Antagonistas del Receptor Purinérgico P2 , Animales , Encéfalo/efectos de los fármacos , Encéfalo/fisiología , Relación Dosis-Respuesta a Droga , Hemodinámica/efectos de los fármacos , Masculino , Actividad Motora/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Receptores Purinérgicos P2X2 , Receptores Purinérgicos P2X3RESUMEN
Extracellular adenosine triphosphate (ATP), acting at P2X ionotropic receptors, is implicated in numerous sensory processes. Exogenous ATP has been shown to be algogenic in both animals and humans. Research focus has been directed towards the P2X(3) receptor, as it is preferentially expressed on nociceptive C-fibers and its implication in pain processing is supported by an altered nociceptive phenotype in P2X(3) knock-out mice. In order to further characterize the role of P2X(3) receptor activation in nociception, we evaluated the effects of continuous intrathecal administration of P2X(3) antisense oligonucleotides for 7 days in the rat. P2X(3) receptor antisense oligonucleotide treatment significantly decreased nociceptive behaviors observed after injection of complete Freund's adjuvant (CFA), formalin or alphabeta-methylene ATP into the rat's hind paw. The anti-hyperalgesic effects of the antisense treatment in the CFA model of inflammatory pain were dose related. Similar effects were observed with two distinct P2X(3) antisense oligonucleotides. These behavioral effects were significantly correlated with a decrease in P2X(3) receptor protein expression in the dorsal root ganglia (DRG). In contrast, a decrease in P2X(3) receptor protein expression in the DRG did not affect nociceptive behavior in the carrageenan model of acute thermal hyperalgesia. P2X(3) receptor antisense oligonucleotide treatment also significantly reduced mechanical allodynia observed after spinal nerve ligation. Overall, the present data demonstrate that activation of P2X(3) receptors contribute to the expression of chronic inflammatory and neuropathic pain states and that relief form these forms of chronic pain might be achieved by selective blockade of P2X(3 )receptor expression or activation.