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Biomedical subjects

S Cortelazzo

Publications and source records attributed to S Cortelazzo.

At least 55 records · Page 3Linked to original sources
PubMed1990

Incidence and risk factors for thrombotic complications in a historical cohort of 100 patients with essential thrombocythemia.

The purpose of this study was to determine which factors were associated with an increased risk of thrombo-hemorrhagic complications in a historical cohort of 100 consecutive and unselected patients with essential thrombocythemia (ET) in whom busulfan treatment was given when platelets were more than 1,000 x 10(9)/L and/or a major thrombotic or hemorrhagic event occurred. The incidence of major hemorrhagic complications was very low (0.33%/person-time at risk [pt-yr]) in comparison with that of thrombotic episodes (6.6%/pt-yr). In an adequate and appropriate control historical group of 200 patients, no severe hemorrhages were recorded and the incidence of thrombotic events was 1.2% pt-yr. Thus, the analysis of risk factors was restricted to this latter group of events. Age, a previous thrombotic event, and long duration of thrombocytosis were identified as major risk factors for thrombosis, while smoking, diabetes mellitus, hyperlipidemia, and hypertension did not influence the rate of thrombotic episodes.

Adolescent↗
PubMed1988

Increased response to arachidonic acid and U-46619 and resistance to inhibitory prostaglandins in patients with chronic myeloproliferative disorders.

In patients with myeloproliferative disorders (MPD) a group of related diseases of the bone marrow stem cell and recurrent haemorrhagic and/or thrombotic complications, the production of aggregating prostaglandins (PGs) may be normal or slightly reduced, while PGI2 production is normal. However, MPD platelet sensitivity to antiaggregatory PGs is still unknown. We studied the potency of PGD2, PGI2 and PGE1 as inhibitors of platelet aggregation induced by threshold aggregating concentrations of arachidonic acid and U-46619-analogue of the cyclic endoperoxide PGH2 in 20 patients with MPD in comparison with healthy controls, with the aim of evaluating the sensitivity of MPD platelets to antiaggregatory PGs. In these patients platelet prostanoid metabolism was normal. However, the functional response of platelets to aggregating and antiaggregating prostanoids was shifted towards potentially increased platelet aggregation response. These findings could have a clinical relevance in view of the haemostatic and thrombotic complications so frequent in MPD.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1988

In vitro platelet adhesion to vascular subendothelium: studies in patients with polycythaemia vera.

In this work we studied platelet adhesion to subendothelial surfaces in 10 patients with polycythaemia vera and 10 healthy volunteers at 40% Hct (corresponding to the mean value of our control group) and 55% Hct (a value roughly corresponding to the mean Hct in polycythaemic patients). Platelet concentration was kept constant at 2.0-2.5 X 10(11)/l. The results indicate that there was a statistically significant increase in adhesion both in controls and in patients with Hct varying from 40% to 55%. The contribution of the higher Hct in promoting platelet adhesion was comparable in the two groups. When red blood cells (RBC) from the patients were tested with platelets from healthy volunteers in cross-over experiments, they promoted adhesion in the same way as control RBC. Similarly, when patients' platelets were mixed with control RBC, adhesion was the same as control platelets. These data indicate that platelet and RBC contribution to this parameter are not significantly modified in this group of polycythaemic patients, provided that platelet and RBC values are adjusted to control range.

Adult↗
PubMed1988

Interaction between platelets and lupus anticoagulant.

10 consecutive patients fulfilled the diagnostic criteria for lupus anticoagulant. 4 had concomitant systemic lupus erythematosus, 1 Waldenstrom's disease and 5 had no apparent underlying disease. Only the case with Waldenstrom's disease presented a bleeding tendency, with bleeding time greater than 20 min; the others had a history of thrombotic complications. A defect of platelet aggregation induced by ADP, epinephrine, collagen and arachidonic acid was documented in the Waldenstrom's disease case whose lupus anticoagulant was an IgM. In the others, lupus anticoagulant, identified as IgG immunoglobulins, produced no aggregation abnormalities. However, beta-thromboglobulin levels in platelets, plasma and urine were consistent with a pattern of platelet activation in all cases. IgG immunoglobulins separated from sera of 6 patients showed lupus anticoagulant activity, with no effects on platelet aggregation of normal platelet-rich plasma, but they induced secretion of beta-thromboglobulin from normal platelets.

Adult↗
PubMed1988

Antiphospholipid antibodies in early repeated abortions: a case-controlled study.

The relation among lupus anticoagulant (LAC), anticardiolipin antibodies (ACA), and repeated abortions was evaluated in a case-controlled study of 49 women with two or more unexplained spontaneous abortions (cases) compared with 141 control subjects, who had had one or more normal pregnancies and no previous spontaneous abortion. The women were admitted to the same hospital where the cases had been identified for acute conditions other than immunologic neoplastic, gynecologic or cardiovascular. LAC was detected in 7 out of 49 cases (14%, 95% confidence limits 8% to 26%) but in none of the 141 controls. Similarly, ACA were detected in four cases (8%, 95% confidence limits 0.3% to 30%) but no controls. These differences in frequency were statistically significant. These findings confirm that LAC and ACA are associated with a history of repeated abortions in clinically asymptomatic patients for immunologic conditions.

Abortion, Habitual↗
PubMed1988

Inhibition of ticlopidine of platelet adhesion to human venous subendothelium in patients with diabetes.

To elucidate the bleeding tendency that follows the administration of ticlopidine, we investigated the skin bleeding time and some ex vivo functions of platelets from nine patients with insulin-dependent diabetes before and 2 weeks after daily doses of 500 mg ticlopidine. Ticlopidine significantly prolonged bleeding time and reduced platelet reactivity to fixed, relatively high concentrations of aggregating agents, without interfering with thromboxane B2 formation. We used a rotating probe device at a relatively low shear rate (570 sec-1) to measure platelet adhesion to human subendothelium. This system was able to detect an impairment of platelet adhesion dependent on glycoprotein (GP) Ib defect (Bernard Soulier syndrome) or on low platelet von Willebrand factor content, but was insensitive to platelet GPIIb-IIIa defect (Glanzmann's thrombasthenia). In our patients, platelet adhesion was consistently reduced after the administration of ticlopidine. We conclude that ticlopidine is an inhibitor of platelet function that modulates the interaction between platelets. The drug also appears to interfere with mechanisms that modulate platelet-subendothelium interaction at relatively low shear rates. This double action could be relevant in the prevention of vasculopathy in patients with diabetes.

Adult↗
PubMed1987

Aspirin and risk of bleeding in patients with thrombocythemia.

Thirty-two patients with thrombocythemia associated with myeloproliferative syndromes were selected on the basis of normal bleeding time and absence of hemorrhagic or thrombotic history. Twenty-five control subjects were studied simultaneously. They were all given a single intravenous infusion of 500 mg of aspirin (lysine acetylsalicylate), and bleeding time was measured two hours later. Both in the control group and in the patient group, aspirin significantly prolonged the bleeding time, but the average prolongation was significantly more pronounced in the patients. In comparison with the control subjects, the patients had a statistically significant reduction of platelet serotonin content and no difference in the production of platelet lipoxygenase derivative 12-HETE or plasma von Willebrand factor properties. Fourteen patients had abnormal platelet aggregation in response to adenosine diphosphate, adrenaline (epinephrine), or collagen. In six of them, all with very low serotonin content, the bleeding time was prolonged above the upper limit of the post-aspirin values in the control group. Thus, cyclooxygenase inhibition by aspirin unmasked a bleeding tendency in patients with a severe reduction in platelet dense bodies content. These findings might be relevant in relation to the use of antiplatelet drugs.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1986

Platelet dysfunction in splenectomized patients with hairy cell leukemia.

Platelet function was assessed in 17 patients with hairy cell leukemia who had undergone splenectomy. Defective PAF-induced aggregation and selective reduction of beta-thromboglobulin were found in platelets from six and eight patients respectively. These defects were not necessarily associated with bleeding complications.

Adult↗
PubMed1986

Generation of procoagulant activity by hairy cells in response to endotoxin and phorbol esters.

Several investigators have suggested that hairy cells are neoplastic B lymphocytes. These cells, however, also share some biological properties with mononuclear phagocytes. A property of these cells is the capacity to generate procoagulant activity (PCA) in response to a variety of stimuli. In this study we investigated the PCA of peripheral blood hairy cells in 19 consecutive patients with hairy cell leukaemia (HCL). Monocyte-depleted blood mononuclear cells, tested immediately after isolation, expressed little, if any, activity. However, after exposure to endotoxin, a marked increase in PCA was observed (42.1 +/- 8.7 vs 1.3 +/- 0.2 units/5 X 10(1) hairy cells). A significant correlation was found between the number of lymphocytes/hairy cell and the level of endotoxin-induced PCA suggesting that lymphocytes potentiate the procoagulant response of hairy cells. When stimulated with 12-0-tetradecanoyl-phorbol-13-acetate (TPA), patients' cells produced about 2-8 times more PCA than endotoxin-stimulated cells. The PCA induced by endotoxin and TPA was identified as tissue factor. These findings suggest some further relationship between hairy cells and monocytes.

Adult↗
PubMed1986

Defective platelet aggregation induced by platelet activating factor in myeloproliferative disorders: deficiency of an aspirin-independent mechanism?

Platelets from 6 out of 10 patients with myeloproliferative disorders showed only a single reversible wave of aggregation when challenged with platelet activating factor (PAF). Preexposure to subthreshold concentrations of adrenaline resulted in a full irreversible response to PAF. Aspirin, however, removed this synergism. In the remaining 4 patients, PAF induced a full response but aspirin abolished the synergism with adrenaline in 2 of them. In platelets from all controls aspirin failed to abolish the synergism between PAF and adrenaline. It is suggested that patients with myeloproliferative disorders lack - to varying degrees - an aspirin-independent mechanism which amplifies the primary response to PAF. Such a mechanism could involve the products of arachidonic acid metabolism catalyzed by lipoxygenase.

Adult↗
PubMed1985

Platelet behavior in patients with TIA: responsiveness to small doses of aspirin.

To study platelet role in cerebrovascular disease, beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4) plasma levels, indices of in vivo platelet activation, were assayed in a group of patients affected by cerebral ischemic attack (transient ischemic attack; TIA). Determinations were carried out within 1 month from the ischemic event and following short-term (1 month) and long-term (1 year) daily administration of low doses (50 mg) of aspirin (ASA). After the cerebral ischemic event, beta-TG and PF4 plasma levels were elevated. beta-TG and PF4 plasma levels did not decrease after 1 month of treatment with ASA and significantly increased in all the patients after 1 year. Such a trend can perhaps be related to the natural course of the disease and associated with the possible occurrence of collagen-induced platelet activation in cerebrovascular patients. Data suggest that although platelet activation occurs in TIA-affected patients, the high levels of beta-TG and PF4 may not be adequate parameters for evaluation of TIA relapses and ASA efficacy.

Adult↗