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Biomedical subjects

C L Balduini

Publications and source records attributed to C L Balduini.

87 records · Page 5Linked to original sources
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Effect of anagrelide on platelet count and function in patients with thrombocytosis and myeloproliferative disorders.

BACKGROUND: Anagrelide is a quinazolin compound developed initially as an inhibitor of platelet aggregation. Since "in vivo" studies demonstrated that it was responsible for thrombocytopenia in humans, anagrelide has been used recently in a small number of patients with thrombocytosis and myeloproliferative disorders. Platelet count was well controlled in the large majority of patients, and only minimal side effects were observed. PATIENTS: Eight patients (5 with essential thrombocythemia, 2 with chronic granulocytic leukemia, and 1 with idiopathic myelofibrosis) received anagrelide (induction dose 4 mg/die; mean maintenance dose 2 mg/die; mean observation time 26 weeks). Complete blood counts were determined 4 times during the first month, and subsequently every month. "In vivo" and "ex vivo" platelet function was studied before anagrelide and after 4 and 10 days of therapy. RESULTS: Platelet count was reduced and maintained below 500 x 10(9)/L in 5 of 8 patients. Headache, palpitation/tachycardia, gastrointestinal symptoms and a decrease in hemoglobin were the side effects. Anagrelide did not modify the leukocyte count or "in vivo"/"ex vivo" platelet function. CONCLUSIONS: Anagrelide may control thrombocytosis in patients with myeloproliferative disorders, even when traditional drugs have failed. When required, anti-aggregating drugs may be associated with anagrelide, since it has no effect on platelet function.

Adult↗
PubMedDate not supplied

Qualitative and quantitative platelet defect with bleeding symptoms as presenting feature of non Hodgkin lymphomas.

A young man with bleeding symptoms, mild thrombocytopenia and abundant marrow megakaryocytes was classified as having idiopathic thrombocytopenic purpura. Neither prednisone therapy nor splenectomy modified the clinical picture. Subsequently, a severe defect of platelet aggregation and release reaction was demonstrated. Fifteen months after the onset of bleeding symptoms, fever and hepatomegaly appeared and the diagnosis of T cell non Hodgkin lymphoma was made on the basis of a histologic review of paraffin sections of the spleen. Chemotherapy induced remission of the lymphoma, disappearance of bleeding symptoms and normalization of the platelet count and function.

Adult↗
PubMedDate not supplied

[Results of splenectomy in 45 cases of idiopathic thrombocytopenic purpura: search of prognostic indices].

We report on the effects of splenectomy in 45 consecutive patients affected by idiopathic thrombocytopenia who did not obtain lasting remission with prednisone therapy. None of the patients had serious complications after surgery, and only one died a year later from an infectious disease. Two years after surgery, 89% of the patients were in remission; 79% had no therapy after splenectomy, while 10% achieved remission in response to additional medical treatment. A significantly better response to splenectomy was obtained in the subjects under 50 years old (90% remission) and by the younger patients who had had a transient response to initial prednisone therapy (100% remission). All patients with thrombocytosis 15 days after surgery were in remission two years later. We were unable to identify parameters constantly associated with a poor response to splenectomy, since at least 25% of the patients with the worst prognostic features obtained lasting remission.

Adolescent↗
PubMedDate not supplied

Changes in composition of platelet membranes after "in vitro" incubation.

Platelet membranes were isolated by the glycerol lysis technique and incubated in Krebs-Ringer phosphate buffer, to determine their chemical modifications occurring during "in vitro" incubation. The main changes observed at the end of the incubation consist in a significant loss of protein components and in the nearly equimolar decrease of sialic acid and galactosamine. Aminoacid analysis indicate that mainly polar aminoacids are lost. SDS-polyacrylamide gel electrophoresis indicates that high molecular weight proteins disappear after incubation, while no relevant differences in the relative ratios between PAS-stained bands were evident. The reported modifications are quite similar to those described in the membranes of in vivo and in vitro aged red cells.

Amino Acids↗
PubMedDate not supplied

Cryopreservation of human platelets using dimethyl sulfoxide and glycerol-glucose: effects on "in vitro" platelet function.

BACKGROUND: The technique of freezing blood platelets could be very useful in the transfusion support of thrombocytopenic patients. The best method of platelet cryopreservation still remains an object of debate, though it has been suggested that dimethyl sulfoxide (DMSO) is more effective than glycerol-glucose as a cryopreservative. However, few studies have directly compared platelets cryopreserved with different methods. METHODS: We compared "in vitro" function of platelets cryopreserved with 5% dimethyl sulfoxide (DMSO) or 3% glycerol-glucose at -140 degrees C. Platelet aggregation and release reaction were studied with a Lumi aggregometer, thromboxane B2 (TxB2) production by radioimmunoassay, and Ca++ movement by the Fura 2 method. RESULTS: Cryopreservation with both of the methods dramatically reduced the ability of platelets to release ATP and to aggregate in response to single agonists. In contrast, cryopreserved platelets maintained their ability to aggregate after stimulation with paired agonists and to produce TxB2. Cytoplasmic Ca++ increase induced by thrombin was observed in the glycerol-preserved platelets, while it was nearly absent in the DMSO-preserved ones. CONCLUSIONS: We suggest that cryopreservation with glycerol-glucose or DMSO induces similar defects of platelet function. The damage is severe, but platelets are still able to respond to strong stimulation.

Blood Platelets↗
PubMedDate not supplied

Platelet composition and function in patients undergoing cardiopulmonary bypass for heart surgery.

BACKGROUND: Previous studies showed severe biochemical and functional damage to platelets in patients undergoing cardiopulmonary bypass for cardiac surgery, and suggested that this derived from the proteolytic action of plasmin on the platelet surface. METHODS: A double-blind study was carried out to compare platelet function and composition in patients randomized to receive the protease inhibitor aprotinin or placebo during reoperation for valvular prosthesis replacement or coronary artery bypass grafting. RESULTS: Flow cytometry with specific monoclonal antibodies and polyacrylamide gel electrophoresis did not show any significant proteolysis of platelet glycoprotein Ib and IIb-IIIa either in the placebo or the aprotinin group. Functional studies were consistent with these results, since ristocetin-induced platelet agglutination was unchanged and platelet aggregation and ATP release induced by collagen and ADP were only slightly reduced by cardiopulmonary bypass. These mild defects in platelet function were partially prevented by aprotinin infusion. CONCLUSIONS: On the basis of our data and those from literature, we suggest that platelets may be affected very little or severely damaged during cardiopulmonary bypass for cardiac surgery, probably depending on some aspects of the technical procedure which remain to be identified. Aprotinin infusion significantly protects platelets in the latter condition, while its role is obviously slight in the former.

Aprotinin↗
PubMedDate not supplied

Activation of the hemostatic process in patients with unruptured aortic aneurysm before and in the first week after surgical repair.

BACKGROUND AND OBJECTIVE: It has been previously suggested that activation of coagulation and fibrinolysis may sometime occur in patients with unruptured aortic aneurysm. However, the incidence of this complication and the effect of surgical repair are unknown. The objective of our study was to gain further information on this topic. METHODS: We investigated activation of the hemostatic process in 20 consecutive patients with unruptured abdominal aortic aneurysm. We then evaluated the effect of surgical repair of the vascular abnormalities. RESULTS: Both before and in the first week after surgery, the large majority of patients showed clear signs of activation of coagulation (increased plasma levels of prothrombin fragment 1 + 2 and fibrin peptide A), and many had low levels of the natural anticoagulant antithrombin III. Platelets were activated in all cases (high levels of plasma beta-thromboglobulin), and signs of platelet consumption (thrombocytopenia and/or increased mean platelet volume) were present in most of them. INTERPRETATION AND CONCLUSIONS: Activation of the hemostatic process occurs in nearly all patients with abdominal aortic aneurysm and could play a role in the hemorrhagic and thrombotic events that can complicate the clinical development of these subjects.

Aged↗