Search PubMed⌕ Search

Biomedical subjects

A Casonato

Publications and source records attributed to A Casonato.

At least 91 records · Page 5Linked to original sources
PubMed1985

Effect of heparin and aspirin on platelet and clotting activation during leukapheresis.

Beta-thromboglobulin (beta TG), serotonin (5HT) and fibrinopeptide A (FPA) were assessed in twenty-two normal donors before, during, and at the end of leukapheresis. Seven procedures were carried out adding heparin to the circuit, and seven adding acetyl salicylic acid (ASA). The remaining eight procedures were carried out using only citrate and served as controls. Plasma beta TG increased both during and after the apheresis, together with a significant decrease of the intra-platelet content. Platelet 5HT did not show significant changes whereas FPA increased significantly. Using heparin, we obtained a complete prevention of FPA cleavage during the entire procedure, while beta TG increased at the middle of the procedure. No significant effects were observed using ASA both on beta TG and FPA levels. These features clearly indicate the activation of platelets and the thrombin generation in the apheresis circuit. Nevertheless, the activation of the clotting system seems to be predominant, as supported by the improved effect of heparin on beta TG and FPA amounts.

Adult↗
PubMed1984

Clinical significance of beta-thromboglobulin in patients with high platelet count.

The aim of the study was to investigate the relevance of beta-thromboglobulin (beta tg) measurement in patients with thrombocytosis. We have, therefore, studied the level of plasma and platelet beta tg in 74 patients with high platelet count in addition to the evaluation of platelet aggregation and platelet serotonin (5-HT) content. The determinations of platelet serotonin content and aggregation are confirmed to be useful in the differentiation between primary and secondary forms of thrombocytosis. The mean plasma level of beta tg in patients with myeloproliferative disease was significantly raised, but the amount observed in subjects with secondary thrombocytosis is increased too. Considering the amount of beta tg in relation to whole blood platelet count (beta tg ratio), no difference was observed between all patients and controls. The beta tg ratio allowed the identification of a group of patients with an increased ratio and a decreased beta tg platelet content who showed the highest occurrence of thrombosis (66%).

Adult↗
PubMed1984

A microplate enzyme-linked immunospecific assay (ELISA) detecting unbound anti-platelet antibodies.

A microplate immune-enzymatic method was developed for detecting serum antiplatelet antibodies. The method involves the use of antigen-coated platelets and alkaline phosphatase-labeled antihuman immunoglobulin. Linear correlation was obtained between the titer of platelet antibodies and substrate conversion. Twenty-four patients with immune thrombocytopenia and 40 normal controls were studied. Eighteen patients and one control were positive. Therefore, sensitivity and specificity were 75% and 97% respectively. ELISA also was found to be more sensitive than the indirect antiglobulin consumption assay (ACA) and appears to be a practical and easy method for routine evaluation of antiplatelet antibodies.

Binding Sites, Antibody↗
PubMed1983

Normal and low molecular weight heparins: interaction with human platelets.

Porcine mucosal heparin was chemically depolymerized. The depolymerization was stopped at different steps to obtain two low molecular weight (LMW) heparins with a molecular weight of 10 000 and 6000, respectively. The LMW heparins were tested in vitro for anti-clotting activities and for platelet serotonin release in different systems in comparison with normal heparins, dermatan and heparan sulphate. After addition of various amounts of heparin preparations to washed platelets, no significant release was observed for all tested heparins. On the contrary, different heparins showed an inhibition of serotonin-release induced by collagen in platelet rich plasma, whereas the ADP-induced release was increased. The effect on the platelet release appears related to the molecular weight. In fact, it is significant only for normal heparins whereas it is not for LMW heparins. A good relation was observed, also, between anti-activated factor X activity/antiglobal clotting activity (Xa/APTT) ratio of different heparins and the effect on platelet release.

Adenosine Diphosphate↗
PubMed1983

Failure of sulphinpyrazone to affect platelet survival in patients with rheumatic heart valvular disease: a double blind study using 75Se-methionine labeled platelets.

We have investigated platelet survival time in 18 patients suffering from valvular heart disease. Platelet survival was performed using the 75Se-methionine method modified by us. Nine of our eighteen patients underwent surgery for heart valve replacement. Platelet survival time was performed before treatment and six months afterwards with placebo or sulfinpyrazone in a double blind study. Before treatment and surgery, platelet survival time was significantly reduced in patients with a history of embolism (P less than 0.0048). In patients receiving valve replacement, platelet survival time was shortened both in the sulfinpyrazone and placebo groups six months after surgery. Of the nine patients not receiving prostheses and with a thrombotic history, treatment with placebo and sulfinpyrazone resulted in improved platelet survival times.

Adult↗
PubMed1982

Potentiation of anticoagulant response to warfarin by sulphinpyrazone: a double-blind study in patients with prosthetic heart valves.

The effect of Sulphinpyrazone on the anticoagulant response to Warfarin was evaluated by a double-blind study in 11 patients with prosthetic heart valves. Six patients received Warfarin and Sulphinpyrazone and 5 Warfarin and placebo. Sulphinpyrazone potentiated the anticoagulant effect of Warfarin. Patients receiving Sulphinpyrazone needed about half the amount of Warfarin as compared to the control group. There were four bleeding episodes in the Sulphinpyrazone group and one episode in the control group. It was difficult to regulate the dose of Warfarin in patients also receiving Sulphinpyrazone.

Adult↗
PubMed1982

75Se-methionine platelet survival studies: a proposal for a mathematical correction of the curve.

We studied platelet survival in 14 cardiac before heart valve replacement using 75Se-methionine 'cohort label'. The temporal variation of plasma and platelet activity was plotted by a continuous curve by means of a computerized interaction of the single points. Then we computed the plasmatic radioactivity fraction used daily for thrombopoiesis and made a subtraction of this aliquot from a experimental activity in the catabolic phase of the slope. Platelet life span obtained after this 'correction' is comparable with the values of random label using 51Cr.

Adult↗
PubMed1981

The possible value of platelet aggregation studies in patients with increased platelet number.

ADP, adrenalin and collagen platelet aggregation studies were performed in 54 patients with elevated platelet counts: 38 patients showed primary thrombocythemia and 16 secondary thrombocytosis. Patients with primary thrombocythemia (78.7%) showed a decrease aggregation pattern while in patients with secondary thrombocytosis platelet aggregation response was entirely normal. An increase in platelet aggregation was obtained in four patients with primary thrombocythemia. The platelet aggregation response did not appear to be related to circulating platelet number. A relationship between increased platelet aggregation and the occurrence of thrombosis was demonstrated. Similarly, a correction between impaired platelet aggregation and bleeding was also present. These results emphasize the diagnostic value of platelet aggregation studies in patients with elevated platelet number.

Adenosine Diphosphate↗
PubMed1981

Evidence for the need of long-term antithrombotic therapy in patients with porcine heterograft heart valve.

The plasma levels of two platelet specific proteins, namely beta-thromboglobulin (beta TG) and platelet factor 4 (PT4), were investigated in 86 patients with different types of artificial valves, biological and disc, at different times after valve insertion. Significant differences were demonstrated for both proteins with increased age of the disc valve. On the other hand, no significant change in the high average levels was shown for patients with porcine heterograft (Hancock). The general view of anticoagulate or antiaggregate lasting only a few months after bioprosthesis insertion has to be carefully evaluated again.

Animals↗
PubMed1981

In vitro and in vivo effects of ditazol on human platelets malonylaldehyde (MDA) production.

Ditazol (4,5-diphenyl-2 bis-hydroxyethylaminoxazol) was tested with regard to its effect in vivo and in vitro on platelet malonyladehyde (MDA) production which seems to be a good marker of prostaglandins metabolism. The drug is a powerful inhibitor of platelet MDA Production induced by thrombin in vitro and this action seems to be due to a "competitive" type effect. "In vivo" experiments showed a significant inhibitory effect on platelet MDA production 4--6 hours after administration of the drug, with return to basal levels within 24 hours.

Adult↗
PubMed1981

Improvement of platelet aggregation abnormalities in thrombocytosis after thrombocytopheresis.

Platelet function tests were performed in three patients with thrombocytosis in myeloproliferative disorders before and after a swift reduction of platelet count by thrombopheresis. The decrease of platelet count obtained after the procedure was reversed in six days. In two patients with platelet aggregation defects, the normalization of aggregation abnormalities was observed after pheresis, followed by a progressive decrease of platelet response until the pre-pheresis values on 6th day. In the third patient with normal platelet aggregation, a progressive increase of platelet aggregation response was noted on the days following thrombopheresis with ischaemic symptoms of a foot toe. In all three patients, the changes of platelet aggregation were accompanied by a related increase of megathrombocytes. In the two patients with platelet aggregation abnormalities, plasma and platelet beta-thromboglobulin levels were related to changes in platelet count and aggregation.

Adult↗
PubMed1980

[Juvenile rheumatoid arthritis appearing after hepatitis. Causal or casual relationship].

High fever, spleen and lymph node enlargement, and joint pains that assumed the character of rheumatoid arthritis in the ensuing months were noted after a viral hepatitis episode in a 21-year-old woman. Serious anaemia and myocarditis also appeared when the picture was at its worst. A lymphoma was suspected, and the spleen and some abdominal lymph nodes were removed. These displayed signs of intense follicular reaction unaccompanied by atypia. The possibility that juvenile rheumatoid arthritis may be triggered by hepatitis is examined.

Adult↗