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Biomedical subjects

S Bellucci

Publications and source records attributed to S Bellucci.

At least 73 records · Page 4Linked to original sources
PubMed1988

Effect of lupus anticoagulant on antithrombogenic properties of endothelial cells--inhibition of thrombomodulin-dependent protein C activation.

We have investigated the effect of purified immunoglobulin G (IgG) on endothelial cell functions in 16 patients with lupus anticoagulant, 9 of whom had systemic lupus erythematosus (SLE). Spontaneous or thrombin-stimulated secretion of prostacyclin (PGI2) by cultured human endothelial cells from umbilical cord vein (HUVEC) was not inhibited by the patient's IgG. Nor was spontaneous release of tissue plasminogen activator (t-PA) or of its inhibitor (PAI) modified in the presence of patient's IgG. The rate of activation of purified protein C (PC) by HUVEC in the presence of thrombin was significantly lowered by patient's IgG or Fab' fragment (inhibition of 43%). Neutralization of this effect was obtained by incubation of a greater quantity of phospholipids (phosphatidylcholine, phosphatidylserine) with the patient's IgG. Activation of PC was also performed using purified rabbit thrombomodulin (TM) and a similar inhibition of the patient IgG was observed (inhibition of 48%) but the activation of Gla-domainless PC was not modified.

Animals↗
PubMed1988

Congenital platelet disorders.

Congenital platelet disorders include thrombocytopathies and thrombocytopenias, which often occur in association. Thrombocytopathies constitute a model for exploring platelet physiology at the molecular level: adhesion, activation, release phenomena, aggregation. Further advances in understanding thrombocytopenias now require studies of medullary physiology. A better knowledge of these disorders is necessary to improve their management.

Blood Platelet Disorders↗
PubMed1988

Analysis of the membrane glycoproteins of platelets in the Wiskott-Aldrich syndrome.

We have examined the plasma membrane glycoproteins of platelets from three unrelated patients with the Wiskott-Aldrich syndrome. Single- or two-dimensional SDS-polyacrylamide gel electrophoresis was performed. Glycoproteins were located by staining for carbohydrate, or by autoradiography when the platelets had been surface-labelled with 125I prior to solubilization. In one patient a slight decrease in the 125I-labelling intensity of GP Ib, GP Ia and a 125I-labelled polypeptide of Mr 168,000 were noted. For the two other patients the glycoprotein profiles were indistinguishable from those of normal subjects. These results clearly indicate that abnormalities in platelet membrane glycoproteins are not a common trait among Wiskott-Aldrich patients, and thus cannot be regarded as primary defects in this disease.

Adolescent↗
PubMed1988

Low doses v conventional doses of corticoids in immune thrombocytopenic purpura (ITP): results of a randomized clinical trial in 160 children, 223 adults.

A randomized clinical trial was performed in 160 children and 223 adults with acute immune thrombocytopenic purpura (ITP). The role of corticoids at this phase of the disease is still controversial. Therefore, patients were randomized to receive either conventional doses (1 mg/kg/day) of corticotherapy or low doses (0.25 mg/kg/day) for 3 weeks. The remission, defined by platelet count superior to 100,000/microliter was studied for adults and children after 6 months and 12 months, respectively. The statistical analysis showed no significant difference between the two corticotherapy regimens neither in children nor in adults. Overall, 74% of children and 41% of adults were in remission. For the first time in acute ITP, a randomized prospective trial showed that both in children and adults low dose corticotherapy (0.25 mg/kg/day) proves to have the same efficacy as conventional doses (1 mg/kg/day).

Acute Disease↗
PubMed1988

Deferoxamine reduces neutrophil-mediated free radical production during cardiopulmonary bypass in man.

We assessed the effects of the iron chelator deferoxamine in 24 adult patients (12 controls, 12 treated) undergoing cardiopulmonary bypass for various cardiac operations. Deferoxamine was given both intravenously (30 mg/kg of body weight, starting 30 minutes before and ending 30 minutes after bypass) and as an additive to the cardioplegic solution (250 mg/L). Right atrial blood samples were taken before, during, and after bypass, and isolated polymorphonuclear neutrophils were evaluated for their capacity to generate superoxide radicals after stimulation with N-formyl-methionyl-leucyl-phenylalanine (FLMP, 10(-7) mol) and phorbol myristate acetate (100 ng/ml). At the same sampling times, measurement of the plasma levels of 6-keto-prostaglandin F1 alpha, the stable derivative of prostacyclin, was used as an index of membrane phospholipid breakdown. The two groups were not significantly different with regard to age, duration of bypass, and quantitative changes in polymorphonuclear neutrophil counts during the operation. Before bypass, the superoxide production of FMLP-stimulated polymorphonuclear neutrophils was comparable in the two groups. Conversely, after bypass, polymorphonuclear neutrophils harvested from deferoxamine-treated patients produced significantly fewer superoxide radicals than those of control patients (1.9 +/- 0.3 versus 3.7 +/- 0.2 nmol/10(6) polymorphonuclear neutrophils per minute, p less than 0.05). Stimulation of polymorphonuclear neutrophils by phorbol myristate acetate yielded similar changes, as the postbypass superoxide production was 12.6 +/- 2.5 nmol/10(6)/min in control patients and 7.1 +/- 0.9 nmol/10(6)/min in those receiving deferoxamine (p less than 0.05). In contrast, plasma levels of 6-keto-prostaglandin F1 alpha were not significantly different between the two groups. We conclude that deferoxamine-exposed polymorphonuclear neutrophils have a decreased oxidative responsiveness, compatible with the fact that they may have been less "primed" by secretagogues released during bypass, as compared with cells of untreated patients. Our results are consistent with the hypothesis that deferoxamine, by inhibiting iron-catalyzed free radical production, may limit the free radical-mediated amplification of the inflammatory response to bypass and as such could be effective in reducing the harmful effects of extracorporeal circulation.

Cardiopulmonary Bypass↗
PubMed1988

[New treatments for Raynaud's syndrome].

Raynaud's phenomenon, either idiopathic or secondary is often severe. It is due to a vasospasm in response to cold, and an increase in sympathetic tone, hyperviscosity and sometimes hyperactivation of platelets and erythrocytes have been reported. New drugs have been developed such as ketanserin, which is a specific inhibitor of serotonin S2 receptors, and has led to a positive response in 38%-80% of patients. The prostaglandins PGE1 and PGI2 were given i.v. in refractory patients and led to a beneficial effect in 50%-70% of cases. These data seem to justify the development of prostaglandin analogues.

Alprostadil↗
PubMed1987

[In vitro bleeding time].

An in vitro model of primary haemostasis, in vitro bleeding time (BT) according to Kratzer and Born, was studied. There was a significant correlation with in vivo BT. The in vitro BT may be easily repeated in the same patient, facilitating the control of haemostasis. It may also permit studying the effect in vitro and/or ex vivo of drugs on primary haemostasis.

Bleeding Time↗
PubMed1986

Essential thrombocythemias. Clinical evolutionary and biological data.

This retrospective study reviewed 94 patients, aged 6 to 90 years, with thrombocythemia. The women/men ratio was 1.76. At onset or, less commonly, during the course of the disease, 45% of the patients presented hemorrhagic manifestations, 29% thrombotic complications, and only 14% the association of hemorrhage and thrombosis. The average platelet count was 1200 X 10(9)/1, with no difference according to sex or age. Platelet hypoaggregation was seen in practically all the cases (94%), although myelofibrosis was less frequent (54%). The frequency of hemorrhages increased when the platelet count was above 1000 X 10(9)/1 (P less than 0.01), but the occurrence of thrombosis was correlated neither with platelet count nor with thrombopathy. Survival time was lengthy: 80% of survival (standard error 6%) was observed at 100 months. Transformation to acute leukemia was observed in five patients. Because the disease course is most often prolonged, therapeutic measures must be conservative: anti-aggregating drugs in small doses, and chemotherapy beginning with nonalkylating agents.

Adolescent↗
PubMed1986

[Course of the manifestations associated with the antiprothrombinase circulating anticoagulant].

Fifteen patients (9 females and 6 males) with the "lupus type" circulating anticoagulant have been studied. The underlying disease was an auto-immune disorder in 11 cases and a malignant hemopathy in 4 cases. The manifestations frequently associated with the lupus inhibitor, such as thrombosis, thrombocytopenia and false-positive VDRL test were analysed. Hemorrhagic syndrome occurred only when thrombocytopenia or acquired abnormality of Willebrand's factor was present. Thrombotic events (8 cases) were frequent. Deep venous thrombosis was complicated with pulmonary embolism in 4 patients. Platelet abnormality, decreased fibrinolytic response or acquired Willebrand's syndrome were found in all patients with a thrombotic event. These different manifestations followed diverging courses in some patients with persistent thrombocytopenia although the anticoagulant had disappeared in 3 cases, negativation of the false-positive VDRL test while the anticoagulant remained unchanged in 1 case, occurrence of a thromboembolic episode although the anticoagulant had disappeared in 1 case.

Adult↗