[Duplex genotyping of CYP2C19*2 and CYP2C19*3 by high-resolution melting curve analysis].

Clopidogrel is a widely used anti-platelet agent for the prevention of arterial thrombosis. It has been suggested that clopidogrel may be less effective in inhibiting platelet aggregation among patients who are carriers of CYP2C19*2 and CYP2C19*3, two loss-of-function CYP2C19 alleles, which are associated with reduced conversion of clopidogrel to its active metabolite. The objective of this research was to develop a simple and accurate method for genotyping of CYP2C19*2 and CYP2C19*3 simultaneously in one closed-tube using high-resolution melting curve (HRM) analysis. Two amplicons bracketing CYP2C19*2 and CYP2C19*3 gene variants were designed, and AT- or GC-rich 5' tails were added to selected primers to ensure two different amplicons with non-overlapping melting curves. Sixty-four random DNA samples were all fast and sensitively genotyped by HRM analysis. This method was validated by DNA sequencingtechnique, and genotypes obtained using the HRM approach perfectly matched the genotypes obtained by DNA sequencing technique. Therefore, this HRM-based assay allows simple and accurate duplex genotyping of CYP2C19*2 and CYP2C19*3 simultaneously in one closed-tube. This method is expected to be applied in clinical laboratory to guide indi-vidual dosage design of clopidogrel.

[Change in ambulatory arterial stiffness index with advancing age and the correlation with 24 hours pulse pressure in healthy individuals].

OBJECTIVE: Ambulatory arterial stiffness index (AASI) has been recently proposed to reflect the dynamic relation between diastolic and systolic blood pressure throughout the whole day. The aim of our study was to investigate the change in AASI with advancing age and the correlation with 24 hours pulse pressure (24 h PP) in healthy individuals. METHODS: 246 healthy subjects [mean age (59.7 +/- 14.6) years, women 38.6%] underwent 24 hours ambulatory blood pressure monitoring (ABPM) in normal life style. The blood pressure recordings, heart rate (HR), mean arterial pressure (MAP) and pulse pressure (PP) were analyzed simultaneously by computer for every 30 minutes during 6:00 am-22:00 pm and every 60 minutes during 22:00 pm-6:00 am. Using all the blood pressure recordings, we plotted diastolic against systolic blood pressure from each individuals and calculated the regression slope. AASI was derived from 1 minus this regression slope. RESULTS: In 246 healthy individuals, AASI increased with age. Among the healthy individuals, the 95th percentile of AASI was 0.56, the upper boundary of the 95% prediction interval of AASI in relation to age were 0.49 at 20 - 39 years, 0.59 at 40 - 59 years, 0.69 at 60 - 79 years, 0.79 at > or = 80 years. The correlation coefficient between AASI and 24 h PP was 0.497 (P < 0.01). AASI linearly increased with age in healthy individuals, whereas the relation between pulse pressure and age was curvilinear. CONCLUSIONS: AASI as a index reflecting blood pressure relationship, manifested the corresponding change with advancing age. The correlation between AASI and traditional index 24 h PP indicated AASI as a new measure of arterial stiffness.