METHODS: The three variants expressed by bacteria were investigated using substrate (omeprazole and 3- cyano-7-ethoxycoumarin[CEC]) and inhibitor (ketoconazole, fluoxetine, sertraline and loratadine) probes in enzyme assays along with molecular docking.
RESULTS: All alleles exhibited very low enzyme activity and affinity towards omeprazole and CEC (6.1% or less in intrinsic clearance). The inhibition studies with the four inhibitors, however, suggested that mutations in different variants have a tendency to cause enhanced binding (reduced IC50 values). The enhanced binding could partially be explained by the lower polar solvent accessible surface area of the inhibitors relative to the substrates. Molecular docking indicated that G91R, R335Q and F448L, the unique mutations in the alleles, have caused slight alteration in the substrate access channel morphology and a more compact active site cavity hence affecting ligand access and binding. It is likely that these structural alterations in CYP2C19 proteins have caused ligand-specific alteration in catalytic and inhibitory specificities as observed in the in vitro assays.
CONCLUSION: This study indicates that CYP2C19 variant selectivity for ligands was not solely governed by mutation-induced modifications in the active site architecture, but the intrinsic properties of the probe compounds also played a vital role.
METHODS: After translation and cross-cultural adaptation, interviews were conducted with 326 participants of the Temuan tribe from village Kampung Tering in Johol, Negeri Sembilan, Malaysia. The instrument's validity was assessed using the scores of MREALD-30, which were compared based on occupation, monthly household income, educational attainment, general literacy, use of dental services, and three dental outcomes. A questionnaire containing socio-behavioral information and validated Malay Oral Health Impact Profile (M-OHIP-14) was also administered. The reliability of the MREALD-30 was assessed by re-administering it to 30 subjects after two weeks. Its correlations evaluated convergent and discriminative validity of MREALD-30 with the level of education and dental visiting habits, monthly household income, respectively. Predictive validity was assessed with M-OHIP-14, while construct validity was evaluated by exploratory factor analysis using the Rasch model.
RESULTS: The internal consistency of the MREALD-30 measured by Cronbach's alpha was 0.89. The test-retest reliability was excellent (ICC 0.95, k = 0.85). MREALD-30 exhibited good construct validity. Rasch analysis showed two factors, and infit mean-square statistics for MREALD-30 were all within the desired range of 0.50-2.0. The discriminant validity and predictive validity were statistically significant (p