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Biomedical subjects

M H Leclerc

Publications and source records attributed to M H Leclerc.

7 recordsLinked to original sources
PubMed1989

Hemostasis development in the lamb fetus and neonate.

Fetal and neonatal lamb hemostasis were studied from the 60th day of pregnancy to birth. Platelet counts and blood coagulation, as assessed by tests such as recalcification time and thromboelastography, were similar in fetuses, neonates, and adult sheep. The values of coagulation factors were low, ie, vitamin K-dependent Factors II, VII, IX, and X remained unchanged (30 and 40% of adult reference values) until the last 10 days of gestation, and then increased until birth (40 to 60%). Values of fibrinogen and Factor V followed a similar pattern, although their activities became identical to adult values at birth. Also, we measured values of protein C and antithrombin III, which are synthesized by the liver. The importance of hepatic failure and fetal vitamin K deficiency were discussed. Factors VIII and XII activities increased gradually during pregnancy to reach adult values at birth. Fetal fibrinolytic activity increased. This could not be explained by the values of tissue-type plasminogen activator (it was not detectable) or by the presence of its fast-acting inhibitor, whose concentration did not decrease.

Animals↗
PubMed1986

[Preliminary study of the use of low-molecular weight heparin to prevent thrombotic risk].

This study involved two stages: In vitro study. Three LMWHs, CY 216-CY 222 (Choay) and PK 10169 (Pharmuka), were compared to standard heparin, SH (Choay), and to a high-molecular-weight heparin, HAF (Choay), which particularly revealed a dissociation of anti-Xa (++) and anti-IIa (+) activities for the LMWHs: (table: see text) In vivo study. Healthy volunteers. Subcutaneously injections of PK 10169 or CY 222 according to various protocols (rythm of injections, dosage). For both LMWHs, the dissociation of anti-Xa and anti-IIa activities reoccurs in vivo. A peak of anti-Xa effect was observed 3 to 4 hours after the injections. The duration period of this activity is about 12 hours. The importance of the global platelet tests HT and TEG (modified for the highest doses) should be noted. Study of haemorrhagic tendencies in patients with slight thrombotic risk. From this preliminary study, protocols with CY 216, CY 222 and PK 10169 are proposed for the prevention of thrombotic risk in orthopaedic surgery (injections at 12-hour intervals).

Dose-Response Relationship, Drug↗
PubMed1985

Treatment of heparin-associated thrombocytopenia and thrombosis with low molecular weight heparin (CY 216).

This report concerns 34 cases of heparin-associated thrombocytopenia in which standard heparin has been systematically replaced by LMW heparin CY 216 Choay. There were 21 women and 13 men, mean age, 69 years. Twenty-six of the 34 cases had thrombotic complications. All of the patients were treated by standard heparin of porcine mucosal origin, in most cases for prevention of deep vein thrombosis and pulmonary embolism. Twenty-six cases occurred along with orthopedic and traumatologic surgery (especially for total hip replacement, 15 cases). Four cases involved vascular surgery and three involved medical thrombotic disease. Standard heparin treatment was always replaced by LMW heparin CY 216. Initial doses were 0.30 ml three times daily, later increased to obtain global hypocoagulability. Surgical procedures (embolectomy and vena cava filter) were carried out when necessary. Five patients had thrombolytic treatment (urokinase) in conjunction with LMW heparin. The overall results were 31 recoveries, but with seven severe sequelae (three amputations and four hemiplegias) most often attributable to the first ischemic attack, and three deaths. For the last 16 patients, indirect platelet aggregation tests were performed (control platelet-rich plasma plus patient platelet-poor plasma plus LMW heparin): nine cases had negative tests, with nine recoveries and seven cases had positive tests, with five recoveries and two deaths.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1976

[Peculiarities of hemostasis in the term newborn infant].

Haemostasis in the new-born is a product of various factors which are both qualitative and quantitative. The only factors that compare in levels and quality with those in the adult are factors V, VIII and XIII. They are alterations in the semi-analytical tests for coagulation except in the Stypven time. In contrast with this deficit shown up in haemostasis by global tests coagulation is normal and in truth there is hypercoagulability. Using Laurell's method of immunoelectrophoresis for levels of alpha 2 M high levels of this are shown contrasting with progressively lowered antithrombitic action. These paradoxes no doubt arise from the fact that neonatal haemostasis is analysed using standardised techniques and reactions which were developed for adult haemostasis, from which it is certainly as different as from those of other animals. Neonatal haemostasis is perfectly balanced in normal conditions. Important changes occur however in respiratory distress where there is a drop in factor V and soluble complexes appear, bringing about rough shapes suggestive of the subclinical syndrome of defibrination. This situation will be further developed in a forthcoming article.

Blood Coagulation Factors↗
PubMedDate not supplied

The white clot syndrome or heparin associated thrombocytopenia and thrombosis (WCS or HATT) (26 cases).

The Authors report a new iatrogenic complication of preventive or curative standard heparinotherapy. This so called "white clot syndrome" or "Heparin associated thrombocytopenia and thrombosis" is an anatomico-clinical entity characterized by severe, multiple, recurrent, arterial and/or venous thromboembolic accidents which are sometimes fatal. They appear, paradoxically, under heparin treatment and are concomitant with thrombocytopenia (generally less than 100 10(9)/l). Antiplatelet immunoallergic phenomena, via type IgG antibodies, induced by heparin, are the most commonly admitted in physiopathology; however they remain controversial. Treatment of "WCS" includes urgent suppression of standard heparin, administration of antivitamin K, or the new generation of low molecular weight heparin. This series presents 26 cases of HATT treated by LMWH (CY 216 CHOAY). Severe complications must be surgically cured. Prevention of WCS or HATT is mandatory by the systematic survey of platelet count during heparinotherapy.

Aged↗