Giampiera Bertolino

Bleeding Tendency of Unknown Origin and Protein Z Levels

known origin showed low levels of protein Z, suggesting that a protein Z assay must be included in

Effect of GPIIb-IIIa complex ligands on calciumion movement and cytoskeleton organization in activated platelets

We studied the influence of the occupancy of the fibrinogen receptor (GP IIb-IIIa complex) on two early aspects of agonist induced platelet activation: the increase of the intracellular Ca2+ concentration and the cytoskeleton reorganization. A monoclonal antibody, a peptide containing the RGD sequence and fibrinogen purified from human plasma were used as GP IIb-IIIa ligands. The obtained results demonstrated that fibrinogen receptor occupancy inhibits Ca2+ movement and cytoskeleton reorganization caused by low thrombin concentration and ADP.

Platelet function after in vivo and in vitro treatment with thrombolytic agents

Whereas in vitro studies showed that plasmin may induce both inhibition and activation of platelets, in vivo and ex vivo investigations suggested that thrombolytic agents are responsible for platelet stimulation. To gain further information on this topic, ex vivo platelet function was studied in 24 subjects with acute myocardial infarction treated with streptokinase or recombinant tissue-type plasminogen activator (rt-PA). Ten patients with acute myocardial infarction who did not receive thrombolytic treatment were also investigated. The data shows that at the end of thrombolytic infusion, the maximal extent of platelet aggregation and adenosine triphosphate release was reduced in treated patients compared with that in untreated ones. In subjects treated with streptokinase, the defect in platelet aggregation derived from both cellular and plasmatic defects. Plasmatic beta-thromboglobulin concentration was significantly reduced after streptokinase, but unchanged after rt-PA. Three days after thrombolytic treatment, platelet aggregation of patients receiving streptokinase or rt-PA was not significantly different from that of untreated subjects. A similar defect in platelet function was obtained in vitro, incubating normal platelet-rich plasma with pharmacologic concentrations of streptokinase. Again, platelet function defect derived from both cellular and plasmatic damages. It cannot be excluded that platelet activation occurs in patients with acute myocardial infarction during the very early phases of thrombolytic treatment. However, it is suggested that a transient defect in platelet function follows both streptokinase and rt-PA infusion.

Intermittent Flushing with Heparin Versus Saline for Maintenance of Peripheral Intravenous Catheters in a Medical Department: A Pragmatic Cluster‐Randomized Controlled Study

BACKGROUND Three meta-analyses conducted in the 1990s concluded that the effect of intermittent flushing with heparin at low concentration (10 U/mL) was equivalent to that of 0.9% sodium chloride flushes in preventing occlusion or superficial phlebitis. No firm conclusion was reached on the safety and efficacy of heparin concentrations of 100 U/mL used as an intermittent flush. PURPOSE To determine whether flushing peripheral intravenous catheters with 3 mL of a 100 U heparin/mL solution instead of saline improves the outcome of infusion devices. METHODS Cluster-randomized, controlled, two-arm, open trial, conducted in a research and teaching hospital in Northern Italy, involving 214 medical patients without contraindications to heparin: 107 randomly allocated to heparin and 107 to saline flushes (control group). Main outcome measure was catheter occlusion and catheter-related phlebitis. RESULTS Patients with either phlebitis or occlusion were 45 (42.1%) in the heparin group and 68 (63.6%) in the saline group (OR 0.41; 95% CI 0.24-0.72; p= 0.002); patients with occlusion alone were 23 (21.5%) and 47 (43.9%), respectively (p= 0.03); patients with phlebitis alone were 28 (26.2%) and 56 (52.6%) respectively (p= <0.001). Similar results were obtained when the analysis was based on catheters. No heparin severe side effects were identified. LIMITATIONS Lack of blinding, patient selection, cluster randomization of periods of treatment. CONCLUSIONS Heparin 100 U/mL in the maintenance of peripheral venous catheters was more effective than saline solution, in that it reduced the number of catheter-related phlebitis/occlusions and the number of catheters per patient, with potential advantages to both patients and the health system. It also appeared safe. However, subjects with platelet or coagulation defects were excluded, and, therefore, caution should be used when prescribing this type of catheter maintenance to patients at risk of bleeding.

Acquired cyclic thrombocytopenia-thrombocytosis with periodic defect of platelet function

Summary A periodic fall of platelet number characterizes an acquired pathological condition named cyclic thrombocytopenia. We observed a patient in whom the episodes of thrombocytopenia (platelet number less than 50×109/l) were followed regularly by thrombocytosis (700–2 300 × 109 platelets/l). The period of platelet count fluctuation was about 30 d. Morphological examination of bone marrow showed the cyclic disappearance of mature and immature megakaryocytes: bone marrow cultures revealed a periodic severe defect of both multilineage and single‐lineage progenitor cell growth. When platelet count was falling, a mild defect of platelet aggregation and ATP release was observed. while platelet function was normal when platelet count was rising. Prednisone. thymopentine. high‐dose intravenous γ‐globulin and splenectomy were without effect. After 4 years of cyclic platelet and megakaryocyte fluctuations, stable amegakaryo‐cytic thrombocypenia developed and the patient died of haemorrhagic stroke.

Interrelation of platelet aggregation, release reaction and thromboxane A2 production

Aggregation of platelets, stimulated by different agonists, was inhibited by omitting sample stirring or by preincubation of platelets with a monoclonal antibody against glycoproteins IIb-IIIa or with a pentapeptide containing the sequence Arg-Gly-Asp-Ser. In platelets stimulated by collagen, ADP and epinephrine, the inhibition of aggregation paralleled a reduction of both release reaction and thromboxane A2 formation. When thrombin was the stimulus, ATP release and thromboxane A2 production were unaffected (or only slightly modified) by the inhibition of platelet aggregation. These data add further evidence to the hypothesis that aggregation supports the activation of platelets stimulated by weak agonists.

The effect of red cells on platelet aggregation: A study with the electronic whole blood aggregometer

Platelet aggregation was studied in the same platelet rich plasma (PRP) by the simultaneous use of Borns optical method and Cardinals electronic method. The maximum rate of impedance change (electronic method) correlated well with both the rate and the extent of aggregation as measured by the optical method. The rate of impedance change was therefore the parameter chosen for the study of the effect of red cells on platelet aggregation. Erythrocytes, both at 40 and 60% haematocrit (Hct.), greatly inhibited platelet aggregation induced by ADP and adrenalin, but only minimally affected platelet aggregation induced by collagen.

Platelet aggregation in platelet rich plasma and whole blood in 18 patients affected by idiopathic myelofibrosis

Platelet aggregation in whole blood (WB) and in platelet rich plasma (PRP) was studied in 18 consecutive patients affected by idiopathic myelofibrosis (IM). On the basis of WB studies, 22% of patients were classified as normo‐aggregating and 22% as hypo‐aggregating, while 55% had spontaneous platelet aggregation (SPA). SPA was observed also when platelets from patients were stirred in the presence of normal erythrocytes, while it never occurred when normal platelets were stirred in the presence of red cells from patients. PRP studies revealed that 33% and 66% of patients were, respectively, hypo‐ and normo‐aggregating. The most frequent abnormality in PRP was represented by defective or absent aggregation response to epinephrine.

Heparin Infusion Facilitates ex vivo Spontaneous Platelet Aggregation in Patients with Acute Myocardial Infarction Who Have Undergone Thrombolytic Therapy

We investigated ex vivo spontaneous platelet aggregation (SPA) in platelet-rich plasma in 37 patients with acute myocardial infarction. It occurred in about 50% of subjects receiving heparin after streptokinase treatment, while it rarely took place in patients who did not receive either streptokinase or heparin and in those treated with streptokinase alone. The study of patients receiving heparin for deep vein thrombosis suggested that SPA may derived from adenosine diphosphate released from platelets during sample handling. We suggest that heparin infusion may facilitate ex vivo platelet activation and that this mechanism is operative in patients with acute myocardial infarction who have undergone thrombolytic therapy.

Cytochemistry of circulating lymphocytes in diabetes mellitus with and without retinopathy and in newly diagnosed type I (insulin dependent) diabetes.

Cytochemical studies have been performed on peripheral blood lymphocytes of 68 diabetic subjects, with various conditions of metabolic control, and 15 newly diagnosed insulin-dependent diabetic patients. 20 patients of the 1 group had diabetic retinopathy. In diabetic patients periodic acid Schiff positivity, acid phosphatase, and N-acetyl-beta-glucosaminidase activities of lymphocytes are fairly impaired, particularly in insulin-dependent diabetes. Concerning the alpha-naphthyl-acetate-esterase activity, the percentage of positive cells with coarse granules is significantly reduced (p less than 0.001) in diabetic patients as compared to controls, without difference related to age and sex. These abnormalities are more evident in patients with poor glyco-metabolic control. In patients with newly diagnosed insulin-dependent diabetes we have found a further decrease in alpha-naphthyl-acetate-esterase activity, and an increase in acid phosphatase and N-acetyl-beta-glucosaminidase activities. Cyto-enzymatic activities are not significantly different in subjects with diabetic retinopathy. The results of peripheral lymphocyte enzymatic activities in diabetics could be related to a depression of the cell-mediated immunity and could enhance the infections risk of these patients. Furthermore our data show an altered immunological balance in subjects with newly diagnosed type I diabetes.