Showing papers on "Beta-thromboglobulin published in 2005"

Platelet Function and Fibrinolytic Activity in Patients with Bronchial Asthma

Abstract: Platelets have the capacity to release mediators with potent inflammatory or anaphylactic properties Platelet factor-4 (PF4) and beta-thromboglobulin (BTG) are two of these mediators On the other hand, plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator (tPA) are two important mediators of fibrinolysis Both mediators are secreted mainly by vascular endothelium Plasma levels of PF4, BTG, PAI-1, and tPA may show changes in chronic inflammatory diseases such as asthma This study examined the role of thrombocytes and the function of the endothelium in asthmatic patients during an attack and during a stable phase Eighteen patients with known allergic asthma who came to our emergency department with an asthma attack and 14 control subjects were included in the study Blood samples were taken after starting therapy with salbutamol inhalation Lung function tests were performed after receiving the first emergency therapy for asthma Plasma levels of PF4, BTG, PAI-1, tPA were determined before starting steroid therapy and after receiving 1 week of steroid therapy Plasma levels of PF4 among patients with an asthma attack were significantly higher than those of controls (1505+/-892 IU/mL vs 925+/-763 IU/mL, p<0001) A further increase in plasma PF4 levels was detected after steroid therapy (1635+/-916 IU/mL) Plasma BTG levels of patients on admission were not statistically different from those in the control group (1404+/-634 IU/mL vs 1522+/-871 IU/mL) An increase was detected after therapy (1716+/-727 IU/mL) and post-treatment plasma levels were statistically meaningful versus the controls Plasma levels of tPA and PAI were statistically higher than those in controls in asthmatic patients on admission (601+/-272 vs 54+/-23 ng/mL for tPA and 752+/-272 ng/mL vs 327+/-143 ng/mL for PAI-1) Further increases were detected in two parameters after 1 week of therapy with steroids (tPA levels were 685+/-296 ng/mL and PAI-1 levels were 835+/-296 ng/mL) There seems to be an increased activity of platelets during an asthma attack Elevated PAI-1 and tPA levels may also indicate the activated endothelium in asthma Increases of plasma levels of PAI-1 and tPA after steroid therapy need further investigation because elevated PAI-1 levels enhance airway remodeling

Transvenous cryoablation reduces platelet activation during pulmonary vein ablation compared with radiofrequency energy in patients with atrial fibrillation.

Abstract: Background Radiofrequency (RF) ablation procedures for atrial fibrillation (AF) are associated with potential risks of thromboembolism, which may be minimized by the use of cryoablation that preserves the integrity of endocardium. The objective of this study was to compare the thrombogenic potential of transvenous cryoablation versus RF ablation during pulmonary vein (PV) isolation. Methods and results Thirty consecutive patients with paroxysmal AF were randomized to undergo segmental PV isolation procedure using 4-mm tip RF ablation (n = 15) or cryoablation (CryoCor, San Diego, CA, USA) (n = 15). Blood samples were drawn after sheath insertion (baseline), after transseptal puncture, before ablation (after heparin administration), and after isolation of a superior PV. Activation of coagulation was measured with plasma levels of prothrombin fragment 1 + 2 (F1 + 2) and thrombin-antithrombin III complex (TAT), and platelets by plasma level of beta-thromboglobulin (beta-TG) and flow cytometric enumerating of P-selectin (CD62)-positive platelets. In both groups, the plasma level of beta-TG, F1 + 2, and TAT were elevated after sheath insertion. The percentage changes in plasma level of beta-TG, F1 + 2, and TAT and CD41/62-positive platelets from baseline after transseptal puncture and before ablation were similar (P > 0.05). However, the percentage changes in CD62-positive platelets from baseline were significantly higher in patients treated with RF ablation (82 +/- 20%) than with cryoablation (22 +/- 14%, P = 0.02), although their plasma levels of beta-TG, F1 + 2, and TAT were not different (P > 0.05). Conclusions Significant platelet and coagulation activations were observed during PV ablation procedures, and heparin administration only prevented activation of coagulation but not platelets. Persistent platelets activation was observed during RF energy application, but not during cryoablation.

The effect of time of day and exercise on platelet functions and platelet-neutrophil aggregates in healthy male subjects.

Abstract: Platelet activation state changes by exercise. The effect of exercise time on platelet activation state and formation of platelet-neutrophil aggregates are not known yet. In this study the effect of exercise and time of day were examined on platelet activity with platelet-neutrophil aggregates. Ten moderately active males aged 27+/- 1.63 (mean+/-S.D.) years completed sub-maximal (70% VO(2max)) exercise trials for 30 min. Blood pressure (BP) was recorded. Venous blood samples were obtained at rest, immediately post-exercise and after 30 min of recovery. Whole blood was analysed for haematocrit (Hct), haemoglobin (Hb), platelet count (PC), mean platelet count (MPV) and platelet aggregation (PA). Platelet-neutrophil aggregates and beta-thromboglobulin (beta-TG) levels were assayed. Platelet count showed significant increase after morning exercise ((236+/- 32)x10(9) l(-1) versus (202+/- 34)x10(9) l(-1) baseline, p < 0.05). Exercise resulted in significantly lower MPV after the evening exercise (9.16+/- 0.5 fl versus 9.65+/- 0.36 fl, p < 0.05). Platelet aggregation by adenosine diphosphate (ADP) decreased after morning exercise and the recovery aggregation levels were significantly different at two different times of the day (68+/- 20% a.m. versus 80+/- 12% p.m., p < 0.05). It was also showed that platelet-neutrophil aggregates increased significantly from baseline after both exercises. Exercise-induced platelet-neutrophil aggregates were higher in the evening (10.7+/- 1.3% p.m. versus 6.4+/- 1.8% a.m., p < 0.0001). It is therefore concluded that besides platelet-platelet aggregation, exercise can cause platelet- neutrophil aggregates. In addition, time of day has an effect on platelet activation related events. Circadian variations of physiological parameters may have an effect on thrombus formation by platelet activation.

Assessment of platelet activity as expressed by plasma levels of platelet factor 4 and beta-thromboglobulin in patients with chronic idiopathic urticaria.

Abstract: Blood platelet significance in inflammation is recognized but poorly characterized in urticaria. It is known that platelets are activated during inflammatory processes and are involved in modulating inflammatory and immune response via various mediator release. The aim of our study was to investigate the functional state of platelets, expressed by release reaction of C-X-C chemokines such as platelet factor 4 (PF-4) and beta-thromboglobulin (beta-TG) in chronic idiopathic urticaria (CIU). Plasma levels of PF-4 and beta-TG, which are established markers of in vivo platelet activation and which play important role in inflammatory processes, were measured by enzyme-linked immunosorbent assay in 19 patients with CIU and in 25 healthy subjects. Mean plasma PF-4 level in CIU patients and control subjects was 5.01 +/- 1.67 and 4.13 +/- 2.05 IU/ml, respectively, whereas that for beta-TG was 29.3 +/- 14.0 and 25.2 +/- 12.6 IU/ml, respectively. In our small study, there have been no significant differences found between the members of the control and CIU group regarding plasma levels of PF-4 and beta-TG. Further studies should be performed to elucidate whether any systemic platelet activation occurs in CIU.

[The secretory activity of blood platelets--beta-thromboglobulin and platelet factor 4 in echinococcosis].

Abstract: UNLABELLED Parasitic infection can cause local or systemic inflammatory process. Antibody-dependent cellular cytotoxicity, with eosinophils as the effector cells, is the major mechanism of antiparasitic defence. The cytotoxic activity against antibody-coated parasites is also demonstrated by blood platelets. Platelets initiate and maintain inflammatory processes, become activated due to contact with immunocompetent cells or due to a direct contact with a parasite. THE OBJECTIVE The aim of the examination was to evaluate the cytotoxic activity of platelets in patients infected with Echinococcus granulosus. MATERIAL AND METHODS The study was conducted on a group of 24 patients (aged 26-69) infected with Echinococcus granulosus, 19 women and 5 men. The patients were treated with albendazole (Zentel) and did not give consent to surgical procedure. Blood for analysis was collected prior to treatment. Patients infected with E. granulosus were subjected to the examination of platelet activation through the assessment of beta-thromboglobulin and platelet factor 4 concentrations. The concentration of beta-thromboglobulin and platelet factor 4 were assayed using a set of ASSERACHROM (Boehringer Mannheim) according to the immunoenzymatic method with labelled antibodies. Platelet count and their morphological parameters were determined with haematologic analyser Technicon H-3 System. Although platelets do not get into a direct contact with the parasite, an increase is observed in the concentrations of beta-thromboglobulin (16.09 +/- 2.68 IU/ml) and platelet factor 4 (8.47 +/- 3.32 IU/ml), which may indicate the involvement of platelets in the parasitic disease.