Changes in protein C, factor VII and endothelial markers after autologous bone marrow transplantation: possible implications in the pathogenesis of veno-occlusive disease.

In a recent prospective study of allogenic bone marrow transplantation we reported that decreases in factor VII and protein C were predictive markers for high risk of veno-occlusive disease (VOD). In order to determine the relative involvement of endothelial and hepatocyte injury in the genesis of VOD, 34 consecutive patients undergoing autologous bone marrow transplantation (BMT) were studied. Conditioning was performed by chemotherapy alone or associated with total body irradiation (TBI).

Biologically active peptides from milk proteins with emphasis on two examples concerning antithrombotic and immunomodulating activities.

The present paper is devoted to the study of short peptides derived from milk proteins with physiological activities. Some of them behaved as opioids, enzyme inhibitors that convert angiotensin I, peptides that enhance calcium absorption, antiaggregating and antithrombotic peptides, and immunomodulating peptides. Some possessed several physiological properties, such as the C-terminal part of bovine alpha s1-casein.

Comparative arterial antithrombotic activity of clopidogrel and acetyl salicylic acid in the pig.

We investigated the comparative antithrombotic properties of clopidogrel, an analogue of ticlopidine, and aspirin, using the Folts' model on femoral arteries in 22 pigs. On each animal, clopidogrel or aspirin were used to treat the thrombotic process on the left femoral artery and to prevent this process on the right femoral artery. Sequentially: an injury and stenosis were carried out on the left femoral artery; the thrombotic process was monitored with a Doppler during a 30-min observation period for cyclic flow reductions or permanent cessation of flow; after the first cyclic flow reduction occurred, clopidogrel (5 mg kg-1) or aspirin (2.

Characterization of a thrombopathy (type delta storage pool disease) affecting a pig colony.

An autosomal recessive thrombopathy in pigs is described and characterized functionally, morphologically and biochemically. The affected pigs have a severe bleeding diathesis and a markedly prolonged bleeding time but normal plasma and platelet von Willebrand factor (vWF) levels. Electron micrographs and fluorescence microscopy with mepacrine reveal reduced numbers of dense granules in platelets as compared to normals.

Inhibition effects of KRDS, a peptide derived from lactotransferrin, on platelet function and arterial thrombus formation in dogs.

KRDS (Lys-Arg-Asp-Ser), a tetrapeptide from human lactotransferrin, was tested for its effects in vitro on dog platelet function and in vivo on femoral arterial thrombus formation in dogs. KRDS inhibited ADP (8 microM)-induced platelet aggregation (IC50: 350 microM) and arachidonic acid (2 mM)-induced thromboxane B2 generation (IC50: 175 microM). In addition, the thrombin (0.

Heterogeneous distribution of Weibel-Palade bodies and von Willebrand factor along the porcine vascular tree.

Vessels obtained from different levels of pig vascular tree were examined by transmission electron microscope, with the aim of determining whether or not their endothelial cells contain Weibel-Palade bodies (WPB). As these organelles are known to store the von Willebrand factor (vWF), a two-step immunogold labeling of this protein also was performed. Our results showed for the first time a heterogeneous distribution of WPB along the vascular tree of the normal pig: These structures were absent from the thoracic aorta, rare in the abdominal aorta, present in myocardial capillaries, and numerous in the inferior vena cava and pulmonary artery.

Purification and analysis of lung and plasma angiotensin I-converting enzyme by high-performance liquid chromatography.

We purified angiotensin I-converting enzyme (ACE) from pig and human lung and plasma for comparison of some physicochemical properties between the endothelial membrane-bound form and the soluble form of the enzyme. After affinity chromatography on Sepharose CL-4B/lisinopril, gel-filtration HPLC on Superose 12 achieved homogeneity for both forms as assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Whatever the source of ACE, the molecular weight was 300 +/- 40 kDa after calibration of Superose 12 with standard globular proteins and 172 +/- 4 kDa by SDS-PAGE, with or without reduction, a result suggesting interactions between the glycopolypeptide chain and the chromatographic gel possibly related to the overall shape and sugar content of the enzyme.

Liver veno-occlusive disease after bone marrow transplantation changes in coagulation parameters and endothelial markers.

Veno occlusive disease (VOD) is a frequent complication of allogenic bone marrow transplantation (BMT) for which no predictive blood markers are available. 39 patients grafted for severe aplastic anemia (18), and leukemia (21) were prospectively studied. Of the 39 patients, 5 leukemic patients, but no aplastic patients developed VOD.

Reduction in thrombus formation by PG-1 F(ab')2, an anti-guinea pig platelet glycoprotein Ib monoclonal antibody.

We have recently demonstrated that intraperitoneal injection into guinea pigs of F(ab')2 fragments of PG-1, a murine monoclonal antibody recognizing the guinea pig homologue of human platelet glycoprotein Ib, produces virtually complete functional block of the platelet von Willebrand factor receptor without inducing a hemorrhagic state. To assess the ability of this antibody to protect against thrombosis resulting from laser-induced injury to mesenteric small arteries, we injected guinea pigs with either PG-1 F(ab')2 (2.3 mg/kg) or with buffer alone 24 hours before study.

Use of prostaglandin E1 for prevention of liver veno-occlusive disease in leukaemic patients treated by allogeneic bone marrow transplantation.

Prostaglandin E1 (PGE1) was used to prevent veno-occlusive disease (VOD) of the liver after allogeneic bone marrow transplantation (BMT) for leukaemia. It was given in continuous i.v.

The antithrombotic effect of KRDS, a lactotransferrin peptide, compared with RGDS.

Due to the functional homologies between milk and plasma coagulations and the molecular homologies between a plasma protein (human gamma-chain fibrinogen) and a milk protein (Kappa-casein), we thought to characterize a RGDS sequence in milk proteins. A KRDS sequence theoretically analogous to RGDS was found in human lactotransferrin. This study compares in 2 species (rat and guinea-pig) in vitro (on platelet aggregation) and in vivo (in an experimental model of arteriolar thrombosis), relative to RGDS, the effects of KRDS and of a modified sequence KRDR.

Role of PGE1 to prevent veno-occlusive disease of the liver after bone marrow transplantation.

Prostaglandin E1 was used to prevent veno-occlusive disease of the liver after allogeneic bone marrow transplantation for leukemia. It was given in continuous IV infusion from day -8 to day 30 after BMT at the dose of 0.3 microgram/kg/h.

Endothelial cells: target for the HIV1 virus?

Plasmatic levels of endothelial markers [von Willebrand's factor (VWF), fibronectin (FN), and angiotensin converting enzyme (ACE)] were measured in patients at various stages of evolution of HIV1 infection. VWF levels were elevated at all stages, while other markers were significantly altered only for the most advanced stages. These results can be interpreted as indicating an endothelial involvement during HIV infection and VWF being the most sensitive marker.

Role of serotonin in arteriolar thrombosis and secondary vasospasm.

Platelets are implicated both in the thrombotic reaction to an intimal lesion of the arteriolar wall and to the resulting vasospasm even if the two phenomena are not linked directly. The spastic reaction is a consequence of the thrombotic process because without localized platelet activation (thrombus formation) there is no vasospastic reaction, but by pharmacological manipulation, the thrombotic reaction can develop without resulting vasospasm. We developed an original experimental model that allowed us to study the thrombotic reaction secondary to localized endothelial injury in arterioles of the mesentery of the rat, as well as the vasospastic reaction downstream to the site of thrombus formation.

Current perspectives in the treatment of thrombotic disorders.

New trends in antithrombotic therapy should reside in a better adaptation, both in potency and in target to the involved thrombogenic mechanism. Thrombogenesis as hemostasis is the result of cooperation between plasma coagulation factors and platelet functions, and these two systems are themselves in equilibrated antagonism with the vessel wall, mainly endothelial cells. These triangular relations between coagulation factors, platelet functions, and endothelial cell reactivity are quantitatively regulated by flow conditions.

Expression of von Willebrand factor in porcine vessels: heterogeneity at the level of von Willebrand factor mRNA.

The expression of the von Willebrand factor (vWF) gene by cultured endothelial cells from the porcine pulmonary artery, aorta, and lung was compared at the levels of messenger (m)RNA and antigen. Steady-state levels of vWF mRNA were determined by dot-blot analysis using a partial human vWF cDNA as the hybridization probe; vWF mRNA from cultured aortic endothelial cells, and vWF antigen secreted into the culture supernatants were barely detectable. In contrast, vWF mRNA and antigen from the pulmonary artery endothelial cells were approximately eight to nine times that demonstrated by aortic cells.

Cutaneous necrosis associated with the lupus anticoagulant.

Extensive cutaneous necrosis of the limbs with sudden onset was observed in 3 women suffering from benign systemic lupus erythematosus. All 3 had a circulating anticoagulant and a positive venereal diseases reference laboratory test without anticardiolipin antibodies. They were successfully treated with pulse methylprednisolone therapy and plasmapheresis.

In vitro interactions between ramiprilat and angiotensin I-converting enzyme in endothelial cells.

Ramiprilat is an angiotensin I-converting enzyme (ACE) inhibitor whose particular lipophilicity may modify its inhibitory activity on the cellular form of this enzyme in comparison to ACE inhibitors that are more hydrophilic. The inhibitory activity of ramiprilat on cellular ACE and its binding to plasma membrane ACE have been studied in cultures of pig vascular endothelial cells. ACE activity in pig pulmonary artery endothelial cells is completely inhibited by 100 nM ramiprilat; the IC50 is 2 nM, whatever the form of ACE: soluble ACE released into the culture medium, cellular ACE studied in a cell monolayer homogenate, or tissue ACE purified from pig lung tissue.