RESUMEN
The effect of Ginkgo biloba on the activity of CYP2C9, the isoform responsible for S-warfarin clearance, was assessed in 11 healthy volunteers who received single 100-mg doses of flurbiprofen, a probe substrate for CYP2C9. Subjects also received either a standardized G biloba leaf preparation (Ginkgold, 3 doses of 120 mg) or matching placebo in a randomized, double-blind, 2-way crossover study. Mean kinetic variables for flurbiprofen with either placebo or G biloba were elimination half-life, 3.9 versus 3.5 hours; total AUC, 57 versus 55 microg/mL h; and oral clearance, 32.9 versus 31.6 mL/min. None of these differences was significant. Based on highperformance liquid chromatography analysis, each 60-mg Ginkgold tablet contained 6.6 mug of amentoflavone and 61.2 microg of quercetin, both previously identified as CYP2C9 inhibitors. These amounts were apparently too low to inhibit CYP2C9 function in vivo. The results confirm previous controlled clinical studies showing no effect of ginkgo on the kinetics or dynamics of warfarin.
Asunto(s)
Antiinflamatorios no Esteroideos/farmacocinética , Hidrocarburo de Aril Hidroxilasas/metabolismo , Flurbiprofeno/farmacocinética , Ginkgo biloba/química , Adulto , Cromatografía Líquida de Alta Presión , Citocromo P-450 CYP2C9 , Interacciones Farmacológicas , Femenino , Humanos , Masculino , Fenotipo , Extractos Vegetales/farmacología , Espectrometría de FluorescenciaRESUMEN
About 40% of the genetic variance of age-related macular degeneration (AMD) can be explained by a common variation at five common single-nucleotide polymorphisms (SNPs). We evaluated the degree to which these known variants explain the clustering of AMD in a group of densely affected families. We sought to determine whether the actual number of risk alleles at the five variants in densely affected families matched the expected number. Using data from 322 families with AMD, we used a simulation strategy to generate comparison groups of families and determined whether their genetic profile at the known AMD risk loci differed from the observed genetic profile, given the density of disease observed. Overall, the genotypic loads for the five SNPs in the families did not deviate significantly from the genotypic loads predicted by the simulation. However, for a subset of densely affected families, the mean genotypic load in the families was significantly lower than the expected load determined from the simulation. Given that these densely affected families may harbor rare, more penetrant variants for AMD, linkage analyses and resequencing targeting these families may be an effective approach to finding additional implicated genes.
Asunto(s)
Predisposición Genética a la Enfermedad , Pruebas Genéticas , Degeneración Macular/genética , Polimorfismo de Nucleótido Simple/genética , Simulación por Computador , Familia , Femenino , Ligamiento Genético , Estudio de Asociación del Genoma Completo , Genotipo , Humanos , MasculinoRESUMEN
A case-control association study for advanced age-related macular degeneration was conducted to explore several regions of interest identified by linkage. This analysis identified a single nucleotide polymorphism just 3' of complement factor I on chromosome 4 showing significant association (P<10(-7)). Sequencing was performed on coding exons in linkage disequilibrium with the detected association. No obvious functional variation was discovered that could be the proximate cause of the association, suggesting a noncoding regulatory mechanism.
Asunto(s)
Factor I de Complemento/genética , Degeneración Macular/genética , Polimorfismo de Nucleótido Simple , Anciano , Estudios de Casos y Controles , Cromosomas Humanos Par 4 , Femenino , Humanos , Desequilibrio de Ligamiento , Masculino , Persona de Mediana Edad , Medición de Riesgo , Factores de Riesgo , Análisis de Secuencia de ADNRESUMEN
The association of variants in complement factors H and B with age-related macular degeneration has led to more intense genetic and functional analysis of the complement pathway. We identify a nonsynonymous coding change in complement factor 3 that is strongly associated with risk of age-related macular degeneration in a large case-control sample.