Platelet Function in Various Haemorrhagic Disorders

1975 ◽  
Author(s):  
T. Mandalaki ◽  
C. Dimitriadou
Keyword(s):  
Platelet Aggregation ◽  
Density Gradient ◽  
Platelet Function ◽  
Factor Xiii ◽  
Platelet Rich Plasma ◽  
Bleeding Tendency ◽  
Factor Xiii Deficiency ◽  
Haemorrhagic Diathesis

Platelet aggregation by ADP, collagen, thrombin and ristocetin was studied systematically both in citrate platelet rich plasma and isolated platelets by density gradient using albumine (according to Nicholls and Hampton) in various cases of congenital haemorrhagic diathesis, namely v. Willebrand disease, Glanzmann disease (thrombasthenia), Thrombopathy (PF3, defect), Factor XIII deficiency and in unclassified hereditary haemorrhagic disorders as well as in acquired bleeding tendency. According to the platelet abnormalities found during this study a classification of “Thrombopathies” observed in Greece is attempted.

Effect Of Factor XIII On Platelet Aggregation. Study Of Platelet Function And Fibrin Stabilization Inhibitors

1981 ◽  
Author(s):  
M Maamer ◽  
O Demay ◽  
M Aurousseau
Keyword(s):  
Platelet Aggregation ◽  
Acetylsalicylic Acid ◽  
Platelet Function ◽  
Factor Xiii ◽  
Platelet Rich Plasma ◽  
Inhibitory Effect ◽  
Photometric Method

There is little information on the participation of Factor XIII in platelet aggregation. Using BORN’s photometric method to study platelet aggregation induced by ADP in vitro on platelet rich plasma (PRP) of rabbit; clot solubility in 1 % monochloracetic acid and incorporation of dansylcadaverin into casein (LORAND L. et al.) to measure plasma FXIII concentration ; we showed that addition of activated F.XIII (F.XIIIa) to a PRP, aggregating power of platelets was significantly increased (+ 30.4 %, p<0.00l). Addition of inactive F.XIII or thrombin + Ca++ in concentrations used to activate F.XIII, had no significant effect on platelet aggregation induced by ADP.When F.XIIIa was added to plasma in presence of F.XIII inhibitors as 3178 AQ (a new synthetic benzothiophen keton derivative) or monodansylcadaverin (DC) in concentrations of (3.27 × 10-4 M and 9.31 × 10-4 m respectively), the platelet aggregation was significantly inhibited (- 48.8 % and - 35.4 % respectively, p<0.001). This inhibitory effect was not seen when dipyridamole or Acetylsalicylic Acid (ASA) in concentrations of (6.18 × 10-4 M and 17.3 × 10-4 M respectively) ware added in PRP in presence of F.XIIIa When platelet aggregation was performed without addition of F.XIIIa the inhibitory effect of 3178 AQ and DC was respectively (- 76.6 % and - 65.1 %, p<0.001), dipyridamole (- 37.6 %, p<0.00l) and ASA (-4.1%, no significant)These results suggest that F.XIIIa increased the platelet aggregation induced by ADP and compounds which are both inhibitors of platelet aggregation and F.XIII would be more potent antithrombotic by acting on platelets and fibrin stabilization, than drugs which are inhibitors of platelet aggregation only.

Effects of Halothane on Platelet Function

1980 ◽  
Vol 44 (03) ◽  
pp. 143-145 ◽  
Author(s):  
J Dalsgaard-Nielsen ◽  
J Gormsen
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Platelet Rich Plasma ◽  
Human Platelets ◽  
Halothane Anaesthesia ◽  
Inhibition Of Platelet Aggregation ◽  
Transient Impairment ◽  
High Concentrations ◽  
Uptake And Release ◽  
Platelet Functions

SummaryHuman platelets in platelet rich plasma (PRP) incubated at 37° C with 0.3–2% halothane for 5–10 min lost the ability to aggregate with ADP, epinephrine and collagen.At the same time uptake and release of 14C-serotonin was inhibited. When halothane supply was removed, platelet functions rapidly returned to normal. However, after high concentrations of halothane, the inhibition of platelet aggregation was irreversible or only partially reversible.The results suggest that halothane anaesthesia produces a transient impairment of platelet function.

The Effect of Barbituric Acid Derivatives on Platelet Function in Vitro and in Vivo

1973 ◽  
Vol 30 (02) ◽  
pp. 315-326
Author(s):  
J. Heinz Joist ◽  
Jean-Pierre Cazenave ◽  
J. Fraser Mustard
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Barbituric Acid ◽  
Platelet Rich Plasma ◽  
Inhibitory Effect ◽  
Primary Response ◽  
Sodium Pentobarbital ◽  
Barbituric Acid Derivatives

SummarySodium pentobarbital (SPB) and three other barbituric acid derivatives were found to inhibit platelet function in vitro. SPB had no effect on the primary response to ADP of platelets in platelet-rich plasma (PRP) or washed platelets but inhibited secondary aggregation induced by ADP in human PRP. The drug inhibited both phases of aggregation induced by epinephrine. SPB suppressed aggregation and the release reaction induced by collagen or low concentrations of thrombin, and platelet adherence to collagen-coated glass tubes. The inhibition by SPB of platelet aggregation was readily reversible and isotopically labeled SPB did not become firmly bound to platelets. No inhibitory effect on platelet aggregation induced by ADP, collagen, or thrombin could be detected in PRP obtained from rabbits after induction of SPB-anesthesia.

Interactions of Staphylokinase with Human Platelets

1995 ◽  
Vol 73 (03) ◽  
pp. 472-477 ◽  
Author(s):  
H R Lijnen ◽  
B Van Hoef ◽  
D Collen
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Specific Binding ◽  
Platelet Rich Plasma ◽  
Human Platelets ◽  
Normal Plasma ◽  
Atp Secretion ◽  
Platelet Disaggregation ◽  
Activation Rate

SummaryThe interactions of recombinant staphylokinase (SakSTAR) with human platelets were investigated in a buffer milieu, in a human plasma milieu in vitro, and in plasma from patients with acute myocardial infarction (AMI) treated with SakSTAR.In a buffer milieu, the activation rate of plasminogen by SakSTAR or streptokinase (SK) was not significantly altered by addition of platelets. Specific binding of SakSTAR or SK to either resting or thrombin- activated platelets was very low. ADP-induced or collagen-induced platelet aggregation in platelet-rich plasma (PRP) was 94 ± 2.7% or 101 ± 1.7% of control in the presence of 0.1 to 20 μM SakSTAR, with corresponding values of 95 ± 2.8% or 90 ± 4.6% of control in the presence of 0.1 to 4 μM SK. No effects were observed on platelet disaggregation. ATP secretion following collagen-induced platelet aggregation was 4.3 ± 0.26 μM for SakSTAR (at concentrations of 0.1 to 20 μM) and 4.4 ± 0.35 μM for SK (at concentrations of 0.1 to 4 μM), as compared to 3.4 ± 0.70 μM in the absence of plasminogen activator.Fifty % lysis in 2 h (C50) of 60 μl 125I-fibrin labeled platelet-poor plasma (PPP) clots prepared from normal plasma or from plasma of patients with Glanzmann thrombasthenia and immersed in 0.5 ml normal plasma, was obtained with 12 or 16 nM SakSTAR and with 49 or 40 nM SK, respectively. C50 values for lysis of 60 μl PRP clots prepared from normal or patient plasma were also comparable for SakSTAR (19 or 21 nM), whereas SK was 2-fold more potent toward PRP clots prepared from Glanzmann plasma as compared to normal plasma (C50 of 130 versus 270 nM).No significant effect of SakSTAR on platelet function was observed in plasma from patients with AMI treated with SakSTAR, as revealed by unaltered platelet count, platelet aggregation and ATP secretion.Thus, no effects of high SakSTAR concentrations were observed on human platelets in vitro, nor of therapeutic SakSTAR concentrations on platelet function in plasma.

scholarly journals Impaired function of platelet membrane glycoprotein IIb-IIIa in end-stage renal disease.

1994 ◽  
Vol 5 (1) ◽  
pp. 36-46
Author(s):  
M P Gawaz ◽  
G Dobos ◽  
M Späth ◽  
P Schollmeyer ◽  
H J Gurland ◽  
...  
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Platelet Aggregation ◽  
Platelet Function ◽  
Uremic Toxin ◽  
Bleeding Tendency ◽  
Fibrinogen Receptor ◽  
Fibrinogen Binding ◽  
Uremic Patients ◽  
Stage Renal Disease

Impaired platelet function and a bleeding tendency are well-recognized complications of chronic renal failure. Because the fibrinogen receptor GPIIb-IIIa plays a central role in platelet aggregation and adhesion to the subendothelium, it was reasoned that a defect in this receptor may underlie the impaired platelet function in uremia. To test this hypothesis, the function of this receptor in the platelets of 11 uremic patients was studied. Aggregation studies were performed with flow cytometric techniques with anti-GPIIb-IIIa conformation-specific monoclonal antibodies (mAb) (anti-LIBS1 and anti-PMI-1). Antifibrinogen and antithrombospondin mAb were used to characterize fibrinogen binding to GPIIb-IIIa and the release of alpha-granules, respectively. Platelets from patients with chronic renal failure showed significantly decreased binding of conformation-dependent anti-LIBS1 mAb after ADP, phorbol myristate acetate, or RGD-peptide stimulation compared with normal controls, suggesting a defect related to the ability of the fibrinogen receptor to undergo a conformational change. Moreover, antifibrinogen and antithrombospondin binding to activated platelets were reduced in uremic patients, implying impairment of both ligand-binding and alpha-granule release. Hemodialysis partially restored GPIIb-IIIa function, which may account for the observed effects of this therapy in restoring platelet aggregation. These findings indicate that platelets of patients with chronic renal failure reveal an aggregation defect at least partially due to an intrinsic GPIIb-IIIa dysfunction and the presence of a putative uremic toxin that inhibits fibrinogen binding to GPIIb-IIIa.

scholarly journals Are Platelet Aggregation Tests the Best Way to Assess New Drugs for Arterial Disease

2018 ◽  
Vol 1 (1) ◽  
pp. 01-03
Author(s):  
Mark I. M. Noble
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Platelet Rich Plasma ◽  
New Drugs ◽  
In Vitro Test ◽  
In Vivo Efficacy ◽  
Experimental Animals ◽  
Stenosed Artery

Over many years, laboratory testing of platelet aggregability have been carried out in attempts to develop drugs that would prevent thrombosis in arteries. The problems encountered included the question of methodology. Blood samples have to be anticoagulated in order to study the platelets. Anti-coagulation with citrate and tests on derived platelet rich plasma did not correlate at all well with thrombus growth in the stenosed coronary arteries of experimental animals and citrate removes the calcium ions which are vital for platelet function. Anticoagulation with heparin also interfered with platelet function, so that now, hirudins are the preferred anticoagulant. However it was observed that if, instead of stimulating platelet aggregation with adrenaline or ADP, serotonin was applied to the preparation, very little aggregation took place in spite of serotonin 5HT2A antagonists being the most potent inhibitors of thrombus growth in experimental animals. Another indicator that primary platelet agggregation is not a predictor of in vivo efficacy was the finding that 5HT2A antagonism inhibited aggregate growth. In a stenosed artery the platelets are activated by increased shear stress and blood turbulence with release of platelet serotonin causing positive feedback activation of more platelets. At present, there does not seem to be a bench in vitro test that accurately predicts in vivo efficacy in stenosed artery occlusive thrombosis.

Enhanced platelet aggregation and activation under conditions of hypothermia

2007 ◽  
Vol 98 (12) ◽  
pp. 1266-1275 ◽  
Author(s):  
Ruben Xavier ◽  
Ann White ◽  
Susan Fox ◽  
Robert Wilcox ◽  
Stan Heptinstall
Keyword(s):  
Cardiac Surgery ◽  
Platelet Aggregation ◽  
Platelet Function ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Baseline Levels ◽  
Spontaneous Aggregation ◽  
High Concentrations ◽  
Induced Aggregation ◽  
P2y12 Antagonist

SummaryThe effects on platelet function of temperatures attained during hypothermia used in cardiac surgery are controversial. Here we have performed studies on platelet aggregation in whole blood and platelet-rich plasma after stimulation with a range of concentrations of ADP, TRAP, U46619 and PAF at both 28°C and 37°C. Spontaneous aggregation was also measured after addition of saline alone. In citrated blood, spontaneous aggregation was markedly enhanced at 28°C compared with 37°C. Aggregation induced by ADP was also enhanced. Similar results were obtained in hirudinised blood. There was no spontaneous aggregation in PRP but ADP-induced aggregation was enhanced at 28°C. The P2Y12 antagonist AR-C69931 inhibited all spontaneous aggregation at 28°C and reduced all ADP-induced aggregation responses to small, reversible responses. Aspirin had no effect. Aggregation was also enhanced at 28°C compared with 37°C with low but not high concentrations of TRAP and U46619. PAF-induced aggregation was maximal at all concentrations when measured at 28°C, but reversal of aggregation was seen at 37°C. Baseline levels of platelet CD62P and CD63 were significantly enhanced at 28°C compared with 37°C. Expression was significantly increased at 28°C after stimulation with ADP, PAF and TRAP but not after stimulation with U46619. Overall, our results demonstrate an enhancement of platelet function at 28°C compared with 37°C, particularly in the presence of ADP.

scholarly journals Improved Antithrombotic Activity and Diminished Bleeding Side Effect of a PEGylated αIIbβ3 Antagonist, Disintegrin

Toxins ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 426
Author(s):  
Yu-Ju Kuo ◽  
Yao Tsung Chang ◽  
Ching-Hu Chung ◽  
Woei-Jer Chuang ◽  
Tur-Fu Huang
Keyword(s):  
Platelet Aggregation ◽  
Side Effect ◽  
Half Life ◽  
Platelet Rich Plasma ◽  
Drug Stability ◽  
Severe Thrombocytopenia ◽  
Bleeding Tendency ◽  
Dependent Manner

Polymer polyethylene glycol (PEG), or PEGylation of polypeptides improves protein drug stability by decreasing degradation and reducing renal clearance. To produce a pharmaceutical disintegrin derivative, the N-terminal PEGylation technique was used to modify the disintegrin derivative [KGDRR]trimucrin for favorable safety, pharmacokinetic profiles, and antithrombotic efficacy. We compared intact [KGDRR]trimucrin (RR) and PEGylated KGDRR (PEG-RR) by in vitro and in vivo systems for their antithrombotic activities. The activity of platelet aggregation inhibition and the bleeding tendency side effect were also investigated. PEG-RR exhibited optimal potency in inhibiting platelet aggregation of human/mouse platelet-rich plasma activated by collagen or ADP with a lower IC50 than the intact derivative RR. In the illumination-induced mesenteric venous thrombosis model, RR and PEG-RR efficaciously prevented occlusive thrombosis in a dose-dependent manner. In rotational thromboelastometry assay, PEG-RR did not induce hypocoagulation in human whole blood even given at a higher concentration (30 μg/mL), while RR slightly prolonged clotting time. However, RR and PEG-RR were not associated with severe thrombocytopenia or bleeding in FcγRIIa-transgenic mice at equally efficacious antithrombotic dosages. We also found the in vivo half-life of PEGylation was longer than RR (RR: 15.65 h vs. PEG-RR: 20.45 h). In conclusion, injectable PEG-RR with prolonged half-life and decreased bleeding risk is a safer anti-thrombotic agent for long-acting treatment of thrombus diseases.

The Effects Of Chemical Alterations Of The Benzoic Acid Nucleus On Platelet Function And Prostacyclin Activity In The Arterial Wall

1981 ◽  
Author(s):  
B A Killackey ◽  
J J Killackey ◽  
R B Philp
Keyword(s):  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Benzoic Acid ◽  
Platelet Function ◽  
Platelet Rich Plasma ◽  
Atp Release ◽  
Rabbit Aorta ◽  
Arachidonic Acid Metabolism ◽  
Second Phase ◽  
Benzoic Acid Derivatives

The effects of a series of benzoic acid derivatives (ASA analogs) on prostacyclin (PGI2) synthesis by rabbit aorta rings and on human platelet function were examined to determine if antiplatelet activity could be separated from anti-PGI2 activity.Rings of rabbit aorta were incubated with or without drugs in Tris 0.05 M, pH 7.5 for 6 m at room temperature (R.T.). Supernatant was then transferred to platelet-rich plasma incubated at 37°C for 3 m. ADP was added 60 s later and aggregation was measured and compared to controls. Rings were also incubated with 14C-arachidonic acid (14C-AA) for 60 m at R.T. in Tris with or without drugs. Products were extracted and measured by radio-T.L.C. along with known standards. Platelet aggregation and release of ATP were measured using a ChronoLog Lumi aggregometer. The effects of these agents on PGI2 activity were similar to their effects on platelet aggregation. ASA however did not exhibit the marked inhibitory potency that it had on the second phase of platelet aggregation and ATP release. Changing the 2-acetoxy group of A.S.A. to a 2-acetyl or 3-propionyloxy resulted in a loss of inhibitory activity in both systems. 2-Propionyloxy substitution resulted in a similar spectrum of activity to ASA. The effects of these agents on the metabolism of 14C-AA by rabbit aorta rings generally confirmed the bioassay results although some of the agents had novel effects on blood vessel arachidonic acid metabolism.Despite potential species differences, this study demonstrates an inability to separate antiplatelet and anti-PGI2 effects with this series of benzoic acid derivatives. Further study of the effects of these agents on the metabolism of 14C-AA by rings of rabbit aorta may lead to a better understanding of PGI2 formation.

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