Circulating Platelet Aggregates

The authors previously reported an increase in platelet aggregation in the days after coronary angiography, accompanied at times by worrying cardiovascular disorders (ventricular fibrillation in one case, death in two others). In the present study, ten patients received a platelet antiaggregating drug (ticlopidin) 5 days before their coronary angiography. No significant changes were detected in the test for circulating platelet aggregates (CPA test) in these patients.

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Increased Plasma Fibrinogen and Circulating Platelet-Aggregates in Type II Hyperlipoproteinaemia

Clinical Science ◽

10.1042/cs056021pb ◽

1979 ◽

Vol 56 (3) ◽

pp. 21P-21P ◽

Cited By ~ 2

Author(s):

G. D. O. Lowe ◽

M. M. Reavey ◽

J. L. H. C. Third ◽

W. F. Bremner ◽

C. D. Forbes ◽

...

Keyword(s):

Plasma Fibrinogen ◽

Type Ii ◽

Circulating Platelet Aggregates ◽

Platelet Aggregates

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The landscape of circulating platelet aggregates in COVID-19

10.1101/2021.04.29.21256354 ◽

2021 ◽

Author(s):

Yuqi Zhou ◽

Masako Nishikawa ◽

Hiroshi Kanno ◽

Tinghui Xiao ◽

Takuma Suzuki ◽

...

Keyword(s):

Large Scale ◽

Multiorgan Failure ◽

Young Patients ◽

Clinical Feature ◽

Platelet Activity ◽

Multiple Organs ◽

Characteristic Clinical Feature ◽

Circulating Platelet Aggregates ◽

Platelet Aggregates ◽

D Dimer

A characteristic clinical feature of COVID-19 is the frequent occurrence of thrombotic events. Furthermore, many cases of multiorgan failure are thrombotic in nature. Since the outbreak of COVID-19, D-dimer testing has been used extensively to evaluate COVID-19-associated thrombosis, but does not provide a complete view of the disease because it probes blood coagulation, but not platelet activity. Due to this limitation, D-dimer testing fails to account for thrombotic events which occur despite low D-dimer levels, such as sudden stroke in young patients and autopsy-identified widespread microthrombi in multiple organs. Here we report the landscape of circulating platelet aggregates in COVID-19 obtained by large-scale single-cell image-based profiling and temporal monitoring of the blood of COVID-19 patients (n = 110). Surprisingly, our analysis shows the anomalous presence of excessive platelet aggregates in nearly 90% of all COVID-19 patients, including those who were not clinically diagnosed with thrombosis and those with low D-dimer levels (less than 1 ug/mL). Additionally, results indicate a strong link between the concentration of platelet aggregates and the severity and mortality of COVID-19. Finally, high-dimensional analysis and comparison with other diseases reveal that COVID-19 behaves as a product of thrombosis (localized) and infectious diseases (systemic), as a cause of systemic thrombosis.

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The Induction of Platelet Aggregates in Healthy Subjects by Venousocclusion

10.1055/s-0039-1682681 ◽

1977 ◽

Author(s):

D.A. F. Chamone ◽

J. Vermylen

Keyword(s):

Healthy Subjects ◽

Light Transmission ◽

Diastolic Pressure ◽

Platelet Rich Plasma ◽

In Vivo Evaluation ◽

Modified Method ◽

Circulating Platelet Aggregates ◽

Platelet Aggregates ◽

Set Up

Circulating platelet aggregates have been observed in various clinical conditions (Wu and Hoak, Lancet, 1974, ii, 924). Using a slightly modified method, we have found that platelet aggregates can be induced in vivo in healthy subjects.Nine volunteers (7 males, 2 females, age 23-38 years) were studied. Blood was drawn from an antecubital vein of one arm immediately before and of the other arm after twenty minutes of occlusion midway between systolic and diastolic pressure. The ratio of the platelet count in platelet-rich plasma (PRP) obtained from blood collected on forma lin-EDTA to that from blood collected on EDTA only was 0.934 + 0.028 (mean ± S.E .) before and 0.768 ± 0.033 after occlusion (p < 0.001 ). Spontaneous aggregation in PRP, measured as percent increase in light transmission during 10 minutes of stirring in the a gg re gome ter, was 4 .20 ± 1.17 before and 3 .80 + I .69 after occlusion (p > 0 .1).This system may help elucidate some of the mechanisms involved in the generation of circulating platelet aggregates. It may also constitute a simple set-up for the in vivo evaluation of drugs affecting platelet function.

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Circulating Platelet Aggregates During Emotional Stress and Cigarette Smoking

10.1055/s-0039-1682422 ◽

1977 ◽

Author(s):

G.F. Gensini ◽

R. Abbate ◽

D. Prisco ◽

G.G. Neri Serneri

Keyword(s):

Platelet Aggregation ◽

Medical Students ◽

Cigarette Smoking ◽

Cigarette Smoke ◽

Emotional Stress ◽

Predictive Value ◽

Normal Values ◽

Circulating Platelet Aggregates ◽

Platelet Aggregates ◽

Clinically Significant

Increased platelet aggregation has been observed in various hypercoagulable states, but its predictive value for thrombosis is so far uncertain. We studied the effect of emotional stress and of cigarette smoking on circulating platelets by platelet aggregates ratio (PAR) according to Wu and Hoak (1974.) in medical students aged 20-22 years. The emotional stress was undergoing a University examination.PAR was measured immediately before the examination, at the end and 15 and 30 min after the examination.PAR was significantly lowered in all the subjects at the end (P<0.0l) and after 15 min (P<0.0l) but returned toward normal values after 30 min. The decrease of PAR suggests the production of reversible circulating platelet aggregates. The effect of smo=king a cigarette has been investigated in 8 students. PAR has been determined before smoking, at the end and after 2,5 and 10 min. Smoking lasted 4 min. In 5 subjects we observed a decrease of PAR at 2 min (P< 0. 01), whereas at 5 and 10 min PAR value became normal. Lettuce cigarette smoke did not affect PAR value. Our results indicate that: 1) – Platelet aggregates are very easily produced in circulating blood; 2)- A low value of PAR does not necessarily indicate a platelet hy=peraggregability clinically significant.

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Increased Plasma Fibrinogen and Platelet-Aggregates in Type II Hyperlipoproteinaemia

10.1055/s-0039-1687455 ◽

1979 ◽

Author(s):

J.L.H.C. Third ◽

G.D.O. Lowe ◽

M.M. Drummond ◽

W.F. Bremner ◽

T.D.V. Lawrie ◽

...

Keyword(s):

Plasma Lipids ◽

Young Patients ◽

Adult Life ◽

Arterial Disease ◽

Arterial Injury ◽

Plasma Fibrinogen ◽

Type Ii ◽

Platelet Aggregate ◽

Circulating Platelet Aggregates ◽

Platelet Aggregates

Plasma-fibrinogen and circulating platelet-aggregates (method of Wu and Hoak1) were measured in 21 patients with Type II hyperlipoproteinaeima and 21 matched control subjects. Patients with hyperlipoproteinaemia had increased levels of fibrinogen (3.5 g/l ± SEM 0.2 vs. 2.5 g/l±0.1, p(0.01) and platelet-aggregates (platelet aggregate ratio 0.71 vs. 0.65, p(0.01). Young patients with hyperlipoproteinaemia had prematurely high fibrinogen levels, and the normal fibrinogen rise durina adult life was abolished. There were no significant correlations between fibrinogen, platelet-aggregates, and plasma lipids (cholesterol, cholesterol fractions, or triglyceride). High librinogen and platelet-aggregate levels may play a part in the development of the premature arterial disease associated with Type II hyperlipoproteinaemia, or may be markers of arterial injury. 1Wu, K.K., Hoak, J.C.Lancet, 1974, ii, 924.

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Effect of Indobufen (K 3920) A New Antiplatelet Agent After Oral Administration in Patients with Vascular Diseases

10.1055/s-0039-1684650 ◽

1979 ◽

Author(s):

S. Coccheri ◽

G.C. Fortunato

Keyword(s):

Platelet Aggregation ◽

Antiplatelet Agent ◽

Vascular Diseases ◽

Maximal Amplitude ◽

Marked Inhibition ◽

Lysis Time ◽

Euglobulin Lysis Time ◽

Circulating Platelet Aggregates ◽

Platelet Aggregates ◽

Induced Aggregation

The antiaggregating effect of a new butyric acid derivative, indobufen (K 3920), was investigated in 30 patients with vascular diseases. A between-patient study was performed by administering 50 mg b.i.d. or 100 mg b.i.d. for 14 days to 2 groups of patients. A series of platelet function and clotting parameters were recorded at the end of the treatment period, both 2 and 24 h after the last administration.A marked inhibition of platelet aggregation was observed in both groups, as shown from the significant changes in maximal amplitude, reaction time and slope of ADP- and collagen-induced aggregation wave.Similar results were observed at the Breddin test in both groups of patients and at all experimental times.Platelet adhesiveness was also reduced and circulating platelet aggregates were normalized in all patients who had abnormal basal values.A shortening of euglobulin lysis time was observed 2 h but not 24 h after administration of both doses.Tolerability was excellent.Indobufen appears to be a promising drug for treatment of vascular diseases where platelet aggregation is involved.

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Platelet Function Parameters In Diabetic Patients

10.1055/s-0038-1653365 ◽

1981 ◽

Author(s):

A I Woods ◽

S S Meschengieser ◽

N M Sutton ◽

M A Lazzari

Keyword(s):

Platelet Aggregation ◽

Platelet Function ◽

Diabetic Patients ◽

Circulating Platelet Aggregates ◽

Diabetic Population ◽

Platelet Aggregates ◽

Spontaneous Platelet Aggregation ◽

Age Range ◽

Induced Aggregation ◽

Ristocetin Cofactor

Abnormalities in platelet function tests have already been described in diabetic patients reflecting platelet hyperreactivity. An attempt to determine which of the tests seemed to be more affected in the diabetic population was done in a group of 34 diabetic patients (20 men and 14 women, age range 15-76). The tests performed included assay of Ristocetin Cofactor (McFarlane et al.) circulating platelet aggregates (CPA) (Wu-Hoak) and platelet aggregation induced by ADP in low concentration (0.6 x 10-6M) and Bovine Factor VIII (0.001 U/ml). In matched controls only 3.5% had a positive aggregation induced by Bovine F VIII and with ADP (0.6 x 10-6M% ) the extent of maximum aggregation was 30%.In 15 of the 34 patients (44%) aggregation induced by ADP in high dilution was greater than 50% and this was the test more frequently affected. The level of Ristocetin Cofactor was increased (>160%) in 12 of 34 patients (35%) and aggregation induced by BF VIII was positive also in 12 patients (35%). The detection of CPA was positive in 9 patients (26%). Two patients had spontaneous platelet aggregation and in them all the other tests performed were also positive. Three patients had 3 of the tests altered, and 11 patients only had 2 affected tests.The assay more affected was the ADP induced aggregation followed by the Ristocetin Cofactor levels and BF VIII induced aggregation. The test less affected was the CPA. A correlation with clinical data will be mentioned.

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Circulating platelet aggregates damage endothelial cells in culture

Journal of Surgical Research ◽

10.1016/j.jss.2017.02.011 ◽

2017 ◽

Vol 213 ◽

pp. 90-99

Author(s):

Chandrakala Aluganti Narasimhulu ◽

Mukesh Nandave ◽

Diana Bonilla ◽

Janani Singaravelu ◽

Chittoor B. Sai-Sudhakar ◽

...

Keyword(s):

Endothelial Cells ◽

Cells In Culture ◽

Circulating Platelet Aggregates ◽

Platelet Aggregates

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Prevention of in vivo Platelet Aggregation by Indobufen in Angina Patients during Exercise

Journal of International Medical Research ◽

10.1177/030006058100900205 ◽

1981 ◽

Vol 9 (2) ◽

pp. 113-119 ◽

Cited By ~ 1

Author(s):

E M Pogliani ◽

R Fantasia ◽

C Perini ◽

G Corvi

Keyword(s):

Platelet Aggregation ◽

Bicycle Ergometer ◽

Crossover Design ◽

Double Blind ◽

Before And After ◽

Circulating Platelet Aggregates ◽

Platelet Aggregates ◽

Induced Aggregation ◽

Platelet Functions

Platelet aggregation induced by 3 concentrations of ADP and collagen was assessed in thirty patients with stable angina, before and after exercise with a bicycle ergometer. The patients received a single oral 200 mg dose of indobufen and placebo according to a crossover design in double-blind conditions. Platelet sensitivity to both aggregating agents increased when exercise was carried out after placebo, whereas indobufen markedly inhibited ADP- and collagen-induced aggregation. Circulating platelet aggregates increased in some patients during exercise after placebo but not after indobufen. These results suggest that effort may be an important factor in activation of platelet functions and that the use of drugs blocking the arachidonate pathway and the release reaction may be appropriate in patients with angina.

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