ABSTRACT
A new method for the rapid enrichment and highly sensitive determination of nickel ion has been developed by using a nanofiber-composite membrane filter, which was fabricated by stacking a nanofibrous material made of nylon 6 over a water-permeable membrane filter. The noncharged nickel-α-furil dioxime complex was adsorbed on a nanofibrous layer of the membrane filter under significantly higher flow rates than those used for conventional solid-phase extraction techniques. Highly sensitive determinations with detection limits at sub-parts per billion levels were achieved by enrichment from 50 mL of the complex solution, and the enrichment was completed within 3 min. The color that was developed on the membrane filter was successfully subjected to visual colorimetric analysis and quantitative determination by solid-phase spectrophotometry. In addition, colorimetric determination was feasible with a handheld spectrometer after elution of the colored agent with 50 µL of acetone. This combination of rapid enrichment and spectrometric measurement in a small-volume sample provides a useful analytical method suitable for on-site analysis, which requires neither expensive instruments nor high laboratory skills.
ABSTRACT
OBJECTIVE: The aim of this study was to investigate the influence of clinical and genetic factors on warfarin dose requirements in the Japanese population. METHODS: We enrolled 125 patients on stable warfarin anticoagulant therapy with an international normalized ratio maintained between 1.5 and 3.0. PCR-based methods were performed to analyze genetic polymorphisms in the genes pharmacokinetically and pharmacodynamically related to warfarin reactions, including cytochrome P450 (CYP) 2C9, vitamin K epoxide reductase complex subunit 1 (VKORC1), gamma-glutamyl carboxylase (GGCX) and factor VII (FVII). RESULTS: The presence of CYP2C9*3 and VKORC1-1639G>A had a significant impact on the mean maintenance dose of warfarin (CYP2C9*1/*1 2.74 +/- 1.24 mg/day vs. *1/*3 and *3/*3 1.56 +/- 0.85 mg/day, P = 0.009; VKORC1-1639AA 2.42 +/- 0.95 mg/day vs. GA 3.71 +/- 1.43 mg/day vs. GG 7.25 +/- 0.35 mg/day, P < 0.001). In the multiple linear regression model, the combination of age, body surface area, and genotypes of CYP2C9*3 and VKORC1-1639G>A explained 54.8% of the variance in warfarin dose requirements. CONCLUSIONS: The influences of CYP2C9*3 and VKORC1-1639G>A on the maintenance dose of warfarin were well-defined in Japanese patients, while polymorphisms of GGCX and FVII did not affect it. The model established in this study might provide us most likely individual maintenance dose based on clinical and genetic backgrounds.
