RESUMEN
BACKGROUND: p53 is a transcription factor that regulates the cell cycle, DNA repair, and apoptosis. A variant at codon 72, rs1042522, results in altered activities for p53 and is, notably, differentially distributed among different ethnic populations. However, associations of this variant with cancer in men of African descent have not been explored. Herein, we tested the hypothesis that rs1042522 was associated with prostate cancer (PCa) risk. MATERIALS AND METHODS: Genotypes were determined by PCR-RFLP methods in a study population of African descent consisting of 266 PCa patients and 196 male controls. RESULTS: Our results indicate that the p53 polymorphism may be associated with increased risk of PCa. Genotypes were significantly and marginally associated with PCa risk using the dominant and log-additive genetic models (OR=1.53, 95% CI: 1.02-2.29, P=0.04; OR=1.33, 95% CI: 0.99-1.78, P=0.06, respectively). After adjusting for age, the associations with PCa remained, but results were not statistically significant (OR=1.48, 95% CI: 0.95-2.31, P=0.08; OR=1.30, 95% CI: 0.95-1.80, P=0.10, respectively). CONCLUSIONS: The present study demonstrates that population-dependent differences in allele frequencies associated with health disparities provide a valuable framework for the interrogation of complex diseases in all populations.
Asunto(s)
Negro o Afroamericano/genética , Polimorfismo Genético , Polimorfismo de Nucleótido Simple/genética , Neoplasias de la Próstata/genética , Proteína p53 Supresora de Tumor/genética , Adulto , Anciano , Anciano de 80 o más Años , Sustitución de Aminoácidos , Arginina/genética , Cartilla de ADN , Etnicidad/genética , Humanos , Masculino , Persona de Mediana Edad , Modelos Genéticos , Prolina/genética , Neoplasias de la Próstata/epidemiología , Factores de RiesgoRESUMEN
The uptake of the amphoteric surfactant, cocamidopropyl betaine (CAB) by a sodium montmorillonite clay was studied with respect to concentration and pH. A series of organoclays was prepared in which the basal spacings were found to depend on both parameters. Adjusting the solution pH during preparation influenced the adoption of either 1.8 or 2.0 nm spacing, whereas the 3.9 nm spacing in the same sample was unaffected. The presence of the carboxyl group in the CAB molecule enabled dispersion of the clay at higher pH by which means pure organoclays of high spacing could be obtained, whereas, without dispersing the clay, mixed populations were obtained. The results indicate the optimum parameters for preparing organoclays of desired spacings for use in clay-reinforced nanocomposites.