In-vitro efficacy of different platelet glycoprotein IIb/IIIa antagonists and thrombolytics on platelet/fibrin-mediated clot dynamics in human whole blood using thrombelastography

Fluorinated Analog NMR s of Organosulfur Compounds from Garlic (Allium sativum): Synthesis, Chemistry and Anti-Angiogenesis and Antithrombotic Studies

We describe the synthesis, reactivity, and antithrombotic and anti-angiogenesis activity of difluoroallicin (S-(2-fluoroallyl) 2-fluoroprop-2-ene-1-sulfinothioate) and S-2-fluoro-2-propenyl-l-cysteine, both easily prepared from commercially available 3-chloro-2-fluoroprop-1-ene, as well as the synthesis of 1,2-bis(2-fluoroallyl)disulfane, 5-fluoro-3-(1-fluorovinyl)-3,4-dihydro-1,2-dithiin, trifluoroajoene ((E,Z)-1-(2-fluoro-3-((2-fluoroallyl)sulfinyl)prop-1-en-1-yl)-2-(2-fluoroallyl)disulfane), and a bis(2-fluoroallyl)polysulfane mixture. All tested organosulfur compounds demonstrated effective inhibition of either FGF or VEG-mediated angiogenesis (anti-angiogenesis activity) in the chick chorioallantoic membrane (CAM) or the mouse Matrigel^® models. No embryo mortality was observed. Difluoroallicin demonstrated greater inhibition (p < 0.01) versus organosulfur compounds tested. Difluoroallicin demonstrated dose-dependent inhibition of angiogenesis in the mouse Matrigel^® model, with maximal inhibition at 0.01 mg/implant. Allicin and difluoroallicin showed an effective antiplatelet effect in suppressing platelet aggregation compared to other organosulfur compounds tested. In platelet/fibrin clotting (anti-coagulant activity), difluoroallicin showed concentration-dependent inhibition of clot strength compared to allicin and the other organosulfur compounds tested.

Adjunctive and alternative approaches to current reperfusion therapy

BACKGROUND AND PURPOSE

Current ischemic stroke reperfusion therapy consists of intravenous thrombolysis given in eligible patients after review of a noncontrast CT scan and a time-based window of opportunity. Rapid clot lysis has a strong association with clinical improvement but remains incomplete in many patients. This review appraises novel adjunctive or alternative approaches to current reperfusion strategies being tested in all trial phases. Summary of Review- Alternative approaches to current reperfusion therapy can be separated into 4 main categories: (1) combinatory approaches with other drugs or devices; (2) novel systemic thrombolytic agents; (3) endovascular medical or mechanical reperfusion treatments; and (4) noninvasive or minimally invasive methods to augment cerebral blood flow and alleviate intracranial blood flow steal.

CONCLUSIONS

Reperfusion treatments must be provided as fast as possible in patients most likely to benefit. Patients who fail to rapidly reperfuse may benefit from other strategies that maintain collateral flow or protect tissue at risk.

Mechanisms of hydroxyethyl starch-induced dilutional coagulopathy

BACKGROUND

The biochemical mechanisms causing dilutional coagulopathy following infusion of hydroxyethyl starch 130/0.4 (HES) are not known in detail.

OBJECTIVES

To give a detailed biochemical description of the mechanism of coagulopathy following 30%in vivo dilution with HES, to present a systematic ex vivo test of various hemostatic agents, and to investigate the hypothesis that acquired fibrinogen deficiency constitutes the most important determinant of the coagulopathy.

METHODS

Dynamic whole blood clot formation assessed by thromboelastometry, platelet count, thrombin generation, and the activities of von Willebrand factor, coagulation factor II, FVII, FVIII, FIX, FX and FXIII were measured in 20 bleeding patients enrolled in a prospective clinical study investigating in vivo substitution of blood loss with HES up to a target level of 30%. Thromboelastometry parameters were further evaluated after ex vivo spiking experiments with fibrinogen, prothrombin complex concentrate (PCC), FXIII, activated recombinant FVIIa (rFVIIa), fresh frozen plasma, and platelets.

RESULTS

Hemodilution reduced maximum clot firmness (MCF), whereas whole blood clotting time (CT) and maximum velocity remained unaffected. All coagulation factor activities were reduced. Fibrinogen, FII, FXIII and FX activities decreased significantly below the levels expected from dilution. The endogenous thrombin potential was unchanged. Ex vivo addition of fibrinogen normalized the reduced MCF and increased the maximum velocity, whereas PCC, rFVIIa and platelets shortened the CT but showed no effect on the reduced MCF.

CONCLUSIONS

Acquired fibrinogen deficiency seems to be the leading determinant in dilutional coagulopathy, and ex vivo addition corrected the coagulopathy completely.