Determination of the trace levels of urinary fibrinopeptides by high-performance capillary electrophoresis / 南方医科大学学报

<p><b>OBJECTIVE</b>To establish a high-performance capillary electrophoresis (HPCE)-based method for detection of trace amount of urinary fibrinopeptide A and B (FPA and FPB, respectively) as the specific molecular markers of thrombus formation in vivo.</p><p><b>METHODS</b>The HPCE system consisted of a 25 cm x 50 microm (inner diameter) coated capillary column, 0.1 mol/L phosphoric acid buffer (pH 2.5) and a UV-detector (wavelength at 190 nm). To improve the sensitivity and reproducibility, solid-phase extraction of FPA and FPB in the urine was performed using a Sep-pak C18 column, with a synthetical fibrinopeptide B-Tyr (FPB-Tyr) as the internal standard.</p><p><b>RESULTS</b>With this HPCE method, optimal separations of FPA, FPB and FPB-Tyr was achieved within 16 min, with the migration time of 7.28 min, 14.31 min and 15.22 min, respectively. The adjusted peak area ratios of FPA or FPB and the internal standard showed good linearity with the corresponding concentrations of FPA or FPB spiked in the urine(R>0.99). Under the above chromatography conditions, the minimum detection concentration of FPA and FPB in untreated urine was 30 microg/L and 40 microg/L, respectively, and the assay precision and recovery of FPA and FPB were acceptable.</p><p><b>CONCLUSION</b>The method we established is reliable and specific for separation and identification of fibrinopeptides and other bioactive peptides.</p>

Nine polymorphisms of fibrinogen gene and their association with plasma fibrinogen levels in Hainan Han population / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the allelic frequencies of polymorphisms of alpha Taq I and beta Bcl I, Hinf I A/C, 448 G/A, beta BsmA I G/C, +1689T/G, -148C/T, -249C/T, -455G/A in Hainan Han population and their association with plasma fibrinogen level.</p><p><b>METHODS</b>Turbidmetric assay was used to measure plasma fibrinogen level of two hundred and thirty-eight healthy individuals. The genotypes were characterized by PCR-RFLP and sequence analysis. The relationships between the genotypes and plasma fibrinogen levels were analyzed by t test and ANOVA.</p><p><b>RESULTS</b>The frequencies of the rare alleles of alpha Taq I and beta Bcl I, Hinf I A/C, 448 G/A, beta BsmA I G/C, +1689T/G, -148C/T, -249C/T, -455G/A polymorphisms were 0.445, 0.239, 0.134, 0.235, 0.273, 0.241, 0.265, 0.441, 0.254 respectively. In the general population, the plasma fibrinogen level is significantly higher in the groups of genotypes -455GA and AA, -148CT and TT, alpha Taq I T1T1 than in the group of wild types(P=0.004, 0.015 and 0.043 respectively). In the men, plasma fibrinogen level is significantly higher in the groups of genotypes -455GA and AA, -148CT and TT, alpha Taq I T1T1, alpha Taq I T1T2 than in the group of wild types(P=0.001, 0.023, 0.003 and 0.032 respectively). In the women, no significant genotype association with plasma fibrinogen level was detected.</p><p><b>CONCLUSION</b>There was linkage disequilibrium between the fibrinogen gene loci. The beta -455G/A beta 448G/A, alpha Fg Taq I polymorphisms were associated with the difference in plasma fibrinogen in men. A(-455), T(-148) and alpha Taq I T1 alleles were associated with higher fibrinogen levels.</p>

Effect of beta-Fibrinogen-455 Gene Polymorphism on Plasma Fibrinogen Levels in Patients with Ischemic Stroke / 中国实验血液学杂志

In large prospective studies, plasma fibrinogen levels have been shown to be an independent risk factor of vascular disease, including ischemic stroke. Elevated plasma fibrinogen in an individual could be due to the presence of predisposing genetic and/or environmental factors, such as smoking. Of the polymorphisms studies to date, the beta-fibrinogen-455 (beta-Fg-455) G-->A substitution in the 5' flanking region is associated with the most consistent difference in plasma fibrinogen levels in both case-control studies and in selected groups of healthy individuals. In order to further elucidate the role of the beta-Fg-455 G-->A substitution in determining fibrinogen levels and susceptibility to ischemic stroke in case-control population, including 104 individuals with verified ischemic stroke and 156 healthy individuals. Turbidimetriy assays were used to measure plasma fibrinogen levels of all samples. The beta-Fg-455 G-->A mutation was identified by the polymerase chain reaction followed by restriction enzyme digestion of the amplified DNA with HaeIII. The plasma fibrinogen level in patients with ischemic stroke [(3.51 +/- 1.09) g/L] was significantly higher than that in the control [(3.08 +/- 0.71) g/L] (P < 0.01). The A-allele is associated with elevated fibrinogen levels in both patients and controls. The plasma fibrinogen levels in controls with A-allele in elder people were higher than in younger people (P < 0.05). Those with A allele in males of ischemic stroke had significantly higher plasma fibrinogen levels in smokers than in non-smokers and ex-smokers (P < 0.05), but it was not significantly difference in subjects of GG genotype (P > 0.05). Our data demonstrates an association of the beta-Fg promoter A-455 allele with higher fibrinogen levels in the general population, and suggests that the A-allele may be a susceptible predictor of ischemic stroke, particularly in aging and smoking.