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    ABSTRACT: Preeclampsia (PE) is a multi-system disorder of human pregnancy, whose etiology remains poorly understood. Preeclamptic women are known to have an increased hypercoagulable state that result in excess fibrin deposition in several organs, which compromises their function. Tissue factor (TF) is the main physiological initiator of blood coagulation and its activity is regulated by a specific inhibitor known as Tissue factor pathway inhibitor (TFPI). Based on the important role of TF and TFPI in hemostasis, we hypothesize that their levels may change in the severe PE contributing to exacerbate hypercoagulable state. Some studies have assessed the balance between TF and TFPI in preeclamptic women, but results are inconsistent. Therefore, the aim of this study was to examine these inconsistencies and to assess TF and TFPI plasma levels in three groups of age matched women; pregnant with severe PE (n = 60), normotensive pregnant (n = 50) and normotensive non-pregnant women (n = 50). There was not significantly different among the three groups for TF plasma levels; severe PE women: 338.4 pg/mL (248.1-457.6), normotensive pregnant women: 301.5 pg/mL (216.4-442.9) and normotensive non-pregnant women 393 pg/mL (310.3-522.9). TFPI plasma levels were higher in severe PE comparing to normotensive pregnant women and normotensive non-pregnant women, 115.8 ng/mL (75-149.8); 80.3 ng/mL (59.6-99.7) and 74.5 ng/mL (47.1-98.0), respectively No difference was found between normotensive pregnant women and normotensive non-pregnant women. As for gestational age, a significant difference in TFPI levels was found between severe PE and normotensive pregnant women up to the 33rd week of pregnancy (p = 0.001), and severe PE and non-pregnant women up to the 34th (p = 0.01). In summary, our results indicated that TF plasma levels did not vary in the studied groups, while TFPI plasma levels were significantly increased in severe PE compared to normotensive pregnant and normotensive non-pregnant women. So, our data do not explain the exacerbated hypercoagulability state observed in severe PE. Further studies evaluating genes expression, TF activity and antigen, total and free TFPI and TFPI-2, both in plasma and obstetric tissues, throughout the pregnancy in PE (mild and severe forms) are required.
    Journal of Thrombosis and Thrombolysis 03/2012; 34(1):1-6. · 1.99 Impact Factor
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    ABSTRACT: Accurate estimation of phytoplankton chlorophyll-a (Chl-a) concentration in turbid waters through remote sensing is a challenge due to the optical complexity of water constituents. Reflectance spectra and concurrent water quality parameters of 225 samples across the Shitoukoumen Reservoir, the drinking water resource for Changchun City, were used to retrieve Chl-a concentration with high total suspended matter (TSM) during 2006–2008. A combination of genetic algorithms and partial least square (GA-PLS) model was established for Chl-a retrieval through GA to select sensitive spectral variables and PLS for regression. To compare GA-PLS performances, the widely accepted three-band algorithm was implemented for Chl-a concentration estimation. Both GA-PLS and the three-band algorithm have stable performance for the aggregated dataset (R2=0.85 and 0.81; RPD=3.95 and 3.61; relative RMSE=31.7% and 34.2%), with the GA-PLS model performing marginally better. The temporal transferability of the models was validated with the dataset collected in 2006 and 2007 respectively as independent dataset, showing that GA-PLS outperformed the three-band algorithm. Our result also indicated that relative error [(Chl-apredicted−Chl-ameasured)/Chl-ameasured] showed good linear relation to TSM: Chl-a ratio (R2=0.84), which implied that TSM concentration exerted significant impact on the accuracy of Chl-a estimation in this case study. As the results were derived from a large number of samples representing a wide range of spatiotemporal variations of pigment under TSM (3.7–472.8mg/L) concentration influence, the GA-PLS model has great potential for Chl-a estimation for inland waters with similar backgrounds. Nevertheless, the three-band algorithm also has its own merit considering its simplicity for implementation.
    Ecological Informatics 07/2012; · 1.98 Impact Factor
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    ABSTRACT: Pre-eclampsia (P-EC) is a major contributor to perinatal and maternal morbidity and mortality worldwide. Its etiology and pathogenesis remains poorly understood, and differential diagnosis is problematic. During a normal pregnancy, coagulation activation is essential for physiological placental hemostasis, but women with P-EC tend to be more hypercoagulable than normal pregnant women. A common proposed mechanism for P-EC is utero-placental thrombosis. Indeed, multiple placental microthrombi are frequently observed in women with P-EC, and these may compromise placental perfusion and fetal development. This suggests that predisposing factors to thrombosis could contribute to the development of P-EC. Thus studying circulating hemostatic proteins may help elucidate some of the pathogenesis of P-EC and may provide a rational basis for its differential diagnosis and effective treatment. Preliminary studies by our group on third-trimester women suggest that raised circulating factor VII (FVII) is a selective marker for P-EC when women with P-EC were compared with healthy nonpregnant or normal pregnant women groups. Plasma FVII levels have shown good sensitivity and specificity for P-EC of 90% and 80%, respectively. However, significant comparable changes in the other tissue factor (TF)-dependent pathway factors (activated FVII), TF, and tissue factor pathway inhibitor were not observed. Thus we propose the use of plasma FVII as a potential marker of P-EC.
    Seminars in Thrombosis and Hemostasis 03/2011; 37(2):125-30. · 4.22 Impact Factor