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Biomedical subjects

M R Boisseau

Publications and source records attributed to M R Boisseau.

12 recordsLinked to original sources
PubMed1992

Influence of selected heparins on human neutrophil functions in vitro.

The effects of four heparin derivatives [unfractionated heparin (UFH) at 5-50 IU/ml, low molecular weight heparin (LMWH) at 2-20 IU/ml, pentasaccharide (Penta) at 5 IU/ml and a synthetic heparinoid (PPS) at 10(-6)-10(-5) M] on various polymorphonuclear (PMN) leukocyte end-functions (aggregation, chemotaxis, phagocytosis and burst) were examined. CR3 expression, actin polymerization and membrane surface charge were also studied to gain more insight on the mechanisms of the action of heparins on PMN. The different heparins were found to have rather different actions. PMN were found to be hyperreactive to PPS. Pentasaccharide hat no effect on PMN functions, while UFH and LMWH had intermediate reactivity, modulating responses in an adenosine-like manner. Interactions of heparins with PMN were attributed to biophysical properties of the molecules rather than to the presence of a specific sequence such as a pentasaccharide. Our results show that certain heparin derivatives, apart their well-known anticoagulant action, modulate polymorphonuclear leukocyte functions that may be involved in vascular injury.

Actins↗
PubMed1992

Quantitation of resistance of leukemic cells to cytosine arabinoside from BrdUrd/DNA bivariate histograms.

The cytotoxicity of ara-C derives from an inhibition of DNA synthesis after incorporation of ara-CTP into DNA. The rate of DNA synthesis can be determined from the amount of bromodeoxy-uridine (BrdUrd) incorporated into cells after a short exposure to BrdUrd. We developed a computer program to quantify the inhibition of the rate of DNA synthesis by analysis of the distribution of BrdUrd/DNA. Inhibition was evaluated in ara-C-sensitive and resistant cells after incubation with different doses of ara-C. An index of resistance to ara-C (RI) was expressed as the ratio of the amount of BrdUrd incorporated into S phase cells incubated with ara-C to that incorporated in the absence of ara-C. In the ara-C-sensitive and resistant HL60 cells, a linear relationship between RI and log ara-C concentration was observed. Small numbers of slightly resistant cells in mixtures of ara-C-sensitive and resistant cells could be determined using this method, making it suitable for clinical use to test the resistance of leukemic cells to ara-C.

Bromodeoxyuridine↗
PubMed1992

Intercalation of anthracyclines into living cell DNA analyzed by flow cytometry.

Anthracyclines (ANT) are used in the treatment of leukemia and other cancers. These drugs have been shown to intercalate between the strands of DNA. In the present study, we show that the amount of ANT intercalated into DNA can be determined by measuring the fluorescence resonance energy transfer (FRET) between Hoechst 33342 (H33342) and ANT bound to DNA. The transfer efficiency was found to depend on the amount of disposable ANT but was independent of the amount of H33342 bound to DNA over a wide range of H33342 concentrations. The method was adapted for flow cytometric measurement of FRET in whole living cells and was used to evaluate the degree of intercalation of daunorubicin (DAU) and idarubicine (IDA) into DAU-sensitive and DAU-resistant leukemic cell lines. ANT intercalation into DNA was affected by factors which modify the intracytoplasmic concentration of ANT, and it was shown that the action of ANT and the resistance to ANT could not be attributed solely to the intercalative effect of the drugs. The method has advantages over previously described methods and represents a useful complementary tool in studies on the mode of action of ANT and the mechanisms of chemoresistance.

Benzimidazoles↗
PubMed1976

[Megakaryocytes and platelets in congenital thrombopathies].

Different HT have been studied with the electron microscope and the findings compared to those in the literature. Five patients with thrombasthenia and three with Willebrand's diseases showed various disorders, usually anisocytosis and hypertrophic open canalicular system, in relation to regenerative states. Thirteen young children with 21-trisomy (2 with leukemia) and 13/15 trisomy (1 case) had enlarged platelets with abnormalities of membranes and vacuoles indicating some metabolic disorders and necrotic lesions. One child with Cooley's anemia showed a few granules and necrotic lesions. All these symptoms were related to regenerative or primitive megakaryocytopathias. The lesion of these latter cell appears in other HT: aberrations of membranes in giant platelets syndroms (J. Bernard and J. P. Soulier syndrome), disorders in membranes and/or granules in thrombopenic thrombopathias, the short platelet life span in May-Hegglin anomaly, storage pool disease in Hermansky-Pudlak syndrome. Finally the ultrastructural abnormalities of the platelets mainly help to distinguish several diseases of megakaryocytes.

Blood Platelet Disorders↗
PubMedDate not supplied

[Decrease of the erythrocyte filterability and cerebrovascular accidents. Study in eighty patients (author's transl)].

Erythrocyte filterability has been studied in 80 patients (44 men and 36 women) with recent stroke (mean age of patients was 68). 200 adults were studied as reference. The filtration time is significantly higher in patients than in normal subjects (p less than 0,001). High individual variations are found in patients, in relation with the presence of cardiovascular risk factors. In conclusion, the role of erythrocyte deformability in cerebrovascular disease is discussed.

Adult↗
PubMedDate not supplied

[Hemostasis].

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Blood Coagulation Factors↗