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Elisabeth Mazoyer

Publications and source records attributed to Elisabeth Mazoyer.

8 recordsLinked to original sources
PubMed2004

Platelet activation and aggregation profile in prolonged external ventricular support.

BACKGROUND: Platelet function plays a major role in the understanding of thromboembolic events in prolonged mechanical support. We studied the platelet activation, platelet aggregation profile, and efficacy of aspirin in patients in whom an external ventricular assist device had been implanted. PATIENTS AND METHODS: Fifteen patients were studied prospectively up to 6 weeks after implantation of the same type of ventricular assist device. Platelet function was studied weekly before daily aspirin administration. Aspirin efficacy was tested ex vivo by measuring platelet aggregation triggered by arachidonic acid. Flow cytometry was used to quantify the spontaneous and induced (adenosine diphosphate stimulation) expression of glycoproteins alphaIIbbeta3, Ibalpha, and CD62P on platelet membranes. The plasma levels of von Willebrand factor (von Willebrand factor activity and von Willebrand factor antigen) and fibrinogen were also determined. RESULTS: Six of the 15 patients (26%) maintained an arachidonic acid-induced platelet aggregation despite daily aspirin treatment (250 mg). CD62P values remained increased during a 5-week postoperative period. Spontaneous levels of glycoproteins alphaIIbbeta3 and Ibalpha on platelet membranes remained within a normal range with a preserved reactivity. The plasma levels of fibrinogen and von Willebrand factor remained increased during the entire study period. CONCLUSION: In patients with an implanted external ventricular assist device, the platelet activation profile displays a persistent activation with a preserved reactivity associated with a persistent high inflammatory state and endothelial activation.

Adolescent↗
PubMed2004

The effects of a polymerized bovine-derived hemoglobin solution in a rabbit model of arterial thrombosis and bleeding.

UNLABELLED: Hemoglobin-based oxygen carriers (HBOCs) have been developed primarily for their oxygenating function and possible use as an alternative to red blood cells during surgery or after major trauma. However, their effect on hemostasis has not been studied extensively. We compared the effects on hemostasis of bovine-derived hemoglobin solution (HBOC-201) with gelatin solution and saline infusion in an experimental model of arterial thrombosis and bleeding. After anesthesia, the Folts model was constructed in 30 rabbits. The common carotid artery was exposed, and a 60% stenosis was induced. A compression injury of the artery was then produced, which triggered a series of cyclic episodes of thrombosis (cyclic flow reductions [CFRs]). After the number of baseline CFRs was counted, animals were assigned randomly to one of three groups (n = 10 each): saline (control), gelatin, or HBOC-201 solution. The effect of studied solutions was observed by recording the number of CFRs during another period and was compared with that of saline. Ear immersion bleeding time was recorded after each CFR period. Gelatin and HBOC-201 had similar effects, manifested by significantly decreased CFRs (from median of 7 to 1 and 6 to 1, respectively) and significantly lengthened bleeding time (from 88 to 98 s and 81 to 102 s, respectively; P < 0.05). Saline infusion had no significant effect on CFRs or bleeding time. HBOC-201 and gelatin had similar effects marked by a reduction in the arterial thrombosis rate and increased bleeding time in rabbits. IMPLICATIONS: In a rabbit thrombosis and hemorrhagic model, a polymerized bovine-derived hemoglobin solution and a gelatin solution infusion decreased arterial thrombosis and lengthened bleeding time.

Animals↗
PubMed2002

Erythropoietin and granulocyte colony-stimulating factor increase plasminogen activator inhibitor-1 release in HUVEC culture.

UNLABELLED: Recombinant human erythropoietin (rHuEPO) is considered to be a mitogenic and chemotactic agent in cultured endothelial cells (ECs). The effect of recombinant granulocyte-macrophage (rGM-CSF) and granulocyte (rG-CSF) colony-stimulating factors on the proliferation of human umbilical vein endothelial cells (HUVECs) has been controversial. METHODS: HUVEC proliferation and the release of endothelial markers in HUVEC culture stimulated by rHuEPO, rGM-CSF and G-CSF were measured. RESULTS: We found the dose-dependent stimulating effect of rHuEPO and rGM-CSF on HUVEC proliferation, but we did not achieve this with rG-CSF. rHuEPO like rG-CSF was an effective agent in stimulating the plasminogen activator inhibitor (PAI)-1 release from HUVECs to a cultured medium, while rGM-CSF failed. CONCLUSION: We suggest that rHuEPO showed prothrombotic changes in HUVEC culture. Our results support the idea of suspected rHuEPO direct prothrombotic role in haemodialysed patients treated with rHuEPO.

Biomarkers↗
PubMed2002

Coagulation abnormalities associated with extensive venous malformations of the limbs: differentiation from Kasabach-Merritt syndrome.

Confusion in the nomenclature of vascular malformations has been a major obstacle to the understanding of these conditions, so that misdiagnosis and treatment inconsistencies are common. Coagulation abnormalities occurring in combination with venous malformations (VM) have been misdiagnosed as Kasabach-Merritt syndrome (KMS), despite marked differences in clinical features, pathology and treatment. A homogenous group of 24 patients with diffuse limb VM was entered into a retrospective chart review study. The VM affected an upper limb in 12 patients, a lower limb in 10 and both in two. Localized intravascular coagulation (LIC) was characterized by a decrease in fibrinogen (0.5-1 g/l), an increase in d-dimers (2-64 micro g/ml) and presence of soluble complex of fibrin (+ to +++). Platelet counts were normal or slightly decreased. Higher VM severity scores were associated with more severe LIC. A number of events such as sclerotherapy, surgery, bone fracture, prolonged immobilization and pregnancy or menstruation triggered conversion of the LIC to disseminated intravascular coagulation (DIC), with bleeding related to factor consumption and multiorgan failure related to disseminated microvascular thrombosis. Clinical symptoms associated with worsening of LIC were pain, thrombosis and bleeding at wound sites or during surgery. None of the patients had the large ecchymotic and inflammatory tumours seen in KMS. Graded permanent elastic compression with heparin therapy was the only effective treatment. In conclusion, VM-associated LIC is a distinctive lifelong coagulopathy that must be differentiated from KMS, which is characterized by platelet trapping within a vascular tumour of infancy. The treatment of the two conditions is very different.

Adult↗
PubMedDate not supplied

Recombinant activated factor VII decreases bleeding without increasing arterial thrombosis in rabbits.

PURPOSE: To compare the effects of recombinant activated factor VII (rFVIIa) and platelet-rich plasma (PRP) in an experimental model of bleeding and arterial thrombosis. METHODS: The Folts model was used in 60 rabbits. After anesthesia, the carotid artery was exposed and a 75% stenosis was induced. A compression injury of the artery triggered a series of cyclic flow reductions (CFRs). After counting baseline CFRs, animals were assigned randomly to one of four groups (n = 15 in each): control, PRP, rFVIIa and placebo. Control animals received 10 mL.kg(-1) of saline while 10 mL.kg(-1) of a hydroxyethyl starch solution (200,000/6%/0.5) were infused in the three other groups. CFRs were measured again, followed by treatment with PRP, rFVIIa or placebo and by a final measurement of CFRs. At the end of each observation period, an ear immersion bleeding time (BT) was measured and a blood sample was drawn for the evaluation of hematological variables. Microvascular bleeding was evaluated at the end of the experiment in grams of blood shed from liver and spleen sections. Results are presented as median (range). RESULTS: rFVIIa shortened the BT and decreased microvascular bleeding as compared with placebo [60 (35-100) sec vs 110 (50-140) sec, P = 0.0019 and 9 (4-24) g vs 17 (5-28) g, P = 0.002, respectively]. rFVIIa did not increase CFRs [3(0-9) vs |(0-5), P = 0.11]. CONCLUSION: rFVIIa led to a decrease in BT and microvascular bleeding but did not significantly affect arterial thrombosis in rabbits.

Animals↗