[A prospective randomized control clinical trial about clopidogrel combined with warfarin versus clopidogrel alone in the prevention of restenosis after femoral-popliteal artery angioplasty].

OBJECTIVE: Using two antithrombotic treatment (clopidogrel vs. clopidogrel combined warfarin) strategies after femoral-popliteal artery angioplasty prospectively, to evaluate which strategy is more effective for the restenosis prevention. METHODS: Totally 50 patients referred for endovascular treatment (including the percutaneous transluminal angioplasty (PTA) and stent implantation) of the superficial femoral artery and popliteal artery from January 2008 to May 2009 were randomly divided into clopidogrel group (group A, 25 cases, 30 limbs) and clopidogrel plus warfarin group (group B, 25 cases, 33 limbs) before operation. Clinical outcomes and restenosis rate of the target lesions were evaluated at 3, 6 and 12 months after operation. RESULTS: Totally 88 patients were screened for participation in the study, 56 patients were included after the follow-up of 12 months. At 3 months, the rates of restenosis were 16.7% in group A and 18.2% in group B (χ² = 0.025, P = 0.874). At 6 months, the accumulated restenosis rates were 36.7% in group A and 36.4% in group B (χ² = 0.001, P = 0.98). At 12 months, the accumulated restenosis rates were 53.3% in group A and 42.4% in group B (χ² = 0.75, P = 0.387). Analysis for the critical limb ischemia sub-group showed that follow-up of 12 months, the accumulated restenosis rate was 8/10 in group A and 6/12 in group B (χ² = 1.023, P = 0.312). CONCLUSION: The clopidogrel alone treatment for PTA or PTA plus stent implantation of femoral popliteal artery has no statistically significant difference in comparison with the clopidogrel combined warfarin treatment in terms of the cumulative vascular restenosis rate at 3, 6, 12 months postoperatively.

[Conditional inhibition of hemozoin formation by chloroquine in vitro].

OBJECTIVE: To study the characteristics of inhibition on hemozoin formation by chloroquine under in vitro condition. METHODS: Under different concentrations (0.5-2 mol/L) of sodium acetate (NaAc) and at the pH range of 4.0-5.0, chloroquine was tested for inhibition of beta-hematin (hemozion) formation by using the HPIA (heme polymerization inhibitory activity) assay. The morphology of beta-hematin crystals was determined by light microscopy. Ultraviolet spectrophotometry was employed to measure beta-hematin content, and the size of beta-hematin crystal was analyzed by X-ray diffraction (XRD). RESULTS: Chloroquine exhibited varied effect on beta-hematin formation, depending on pH value and Na+ concentration. When the NaAc concentration increased from 0.5 mol/L (pH 4.2) to 2 mol/L (pH 4.8), the chloroquine inhibitory effect also increased. Results suggested that there exists a threshold pH, below which the beta-hematin formation escalates and chloroquine inhibition declines, and at or above which chloroquine exerts a stronger inhibitory effect on beta-hematin formation. With the increase of pH from 4.4 to 4.8, the crystallinity and the size of crystal changed from 6.93% and 357 angstrom to 6.32% and 264 angstrom, respectively. When pH reached to 5, no more beta-hematin formed. Chloroquine could reduce the crystallinity and crystal size of beta-hematin at same pH value. Morphology analysis on the samples was consistent with the above results. CONCLUSION: Chloroquine inhibits hemozoin formation only when the pH value is at or above threshold pH.