A Comparison of Spontaneous Platelet Aggregation in Whole Blood with Platelet Rich Plasma: Additional Evidence for the Role of ADP

1984 ◽  
Vol 51 (01) ◽  
pp. 115-118 ◽  
Author(s):  
A R Saniabadi ◽  
G D O Lowe ◽  
J C Barbenel ◽  
C D Forbes
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Blood Platelet ◽  
Creatine Phosphate ◽  
Grade Ii ◽  
Autologous Platelet Rich Plasma ◽  
Spontaneous Aggregation ◽  
Spontaneous Platelet Aggregation ◽  
Aggregation Of Platelets

SummaryADP, generated from red blood cells is believed to be responsible for the spontaneous aggregation of platelets in whole blood. This notion is based mainly on the use of enzymes which remove ADP. We have studied spontaneous platelet aggregation in whole blood and autologous platelet rich plasma obtained from 12 healthy male and female volunteers. Platelet aggregation was quantitated by measuring the fall in the number of single platelets counted using a whole blood platelet counter (Ultra Flo 100). In a rotating tube model, the mean fall in the number of platelets due to spontaneous aggregation was 56% in whole blood but, only 3% in platelet rich plasma prepared from the same blood samples. Spontaneous platelet aggregation in whole blood was unaffected by apyrase grade I, but was reduced to 15% by apyrase grade II, to 38% by creatine phosphokinase/creatine phosphate and to 9% by pyruvate kinase/phosphoenolpyruvate. The results of this study provide additional evidence that ADP generated in whole blood triggers the spontaneous aggregation of platelets.

EFFECT OF DIPYRIDAMOLE ON SPONTANEOUS PLATELET AGGREGATION IN WHOLE BLOOD DECREASES WITH THE TIME AFTER VENEPUNCTURE:EVIDENCE FOR THE ROLE OF ADP

1987 ◽  
Author(s):  
A R Saniabadi ◽  
G D O Lowe ◽  
C D Forbes
Keyword(s):  
Platelet Aggregation ◽  
Correlation Coefficient ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Blood Platelet ◽  
Inhibitory Effect ◽  
Time Interval ◽  
Adp Receptor ◽  
Spontaneous Platelet Aggregation

Spontaneous platelet aggregation (SPA) was studied in human whole blood at 3,5, 10, 20, 30, 40 and 60 minutes after venepuncture. Using a whole blood platelet counter (Ultra Flo 100), SPA was quantified by measuring the fall in single platelet count upon rollermixing aliquots of blood at 37°C. The extent of SPA increased with the time after venepuncture, with a correlation coefficient of 0.819. The inhibitory effect of dipyridamole (Dipy) on SPA was studied: (a) 10-5M at each time interval; (b) 0.5-100 x 10-6M at 3 and 30 minutes, and (c) 15 x 10-6M in combination with 2 x 10-4M adenosine (Ad), 8 x 10-6M 2-chloradenosine (2ClAd, a specific ADP receptor blocker) and 5 x 10-5M aspirin. There was a rapid decrease in the inhibitory effect of Dipy with the time after venepuncture; the correlation coefficient was -0.533. At all the concentrations studied, Dipy was more effective at 3 minutes than at 30 minutes after venepuncture. A combination of Dipy withAd, 2ClAd or aspirin was a more effective inhibitor of SPA than either drug alone. However, when an effective concentration of Dipy and an ineffective concentration of Ad (10-4M) were addedtogether, the inhibitory effect of Dipy was not increased, suggesting that Dipy inhibits platelet aggregation independent of Ad.The increase in SPA with the time after venepuncture was abolished when bloodwas taken directly into the anticoagulant containing 2ClAd (5 x 10-6M). We conclude that ADP released from the red blood cells is responsible for the increased platelet aggregability with the time after venepuncture, and makes a serious contribution to the artifacts ofin vitro platelet function studies. Furthermore, the decrease in the inhibitory action of Dipy with the time after venepuncture may explain why previously, it has not been possible to observe inhibition of platelet aggregation by Dipy in platelet rich plasma which requires time to prepare.

Effect of Dipyridamole on Spontaneous Platelet Aggregation in Whole Blood Decreases with the Time After Venepuncture: Evidence for the Role of ADP

1987 ◽  
Vol 58 (02) ◽  
pp. 744-748 ◽  
Author(s):  
A R Saniabadi ◽  
G D O Lowe ◽  
J C Barbenel ◽  
C D Forbes
Keyword(s):  
Platelet Aggregation ◽  
Correlation Coefficient ◽  
Whole Blood ◽  
Blood Platelet ◽  
Inhibitory Effect ◽  
Time Interval ◽  
Adp Receptor ◽  
Spontaneous Platelet Aggregation

SummarySpontaneous platelet aggregation (SPA) was studied in human whole blood at 3, 5, 10, 20, 30, 40 and 60 minutes after venepuncture. Using a whole blood platelet counter, SPA was quantified by measuring the fall in single platelet count upon rollermixing aliquots of citrated blood at 37° C. The extent of SPA increased with the time after venepuncture, with a correlation coefficient of 0.819. The inhibitory effect of dipyridamole (Dipy) on SPA was studied: (a) 10 μM at each time interval; (b) 0.5-100 μM at 3 and 30 minutes and (c) 15 μM in combination with 100 μM adenosine, 8 μM 2-chloroadenosine (2ClAd, an ADP receptor blocker) and 50 μM aspirin. There was a rapid decrease in the inhibitory effect of Dipy with the time after venepuncture; the correlation coefficient was -0.533. At all the concentrations studied, Dipy was more effective at 3 minutes than at 30 minutes after venepuncture. A combination of Dipy with adenosine, 2ClAd or aspirin was a more effective inhibitor of SPA than either drug alone. However, when 15 μM Dipy and 10 μM Ad were added together, the inhibitory effect of Dipy was not increased significantly, suggesting that Dipy inhibits platelet aggregation independent of Ad. The increase in SPA with the time after venepuncture was abolished when blood was taken directly into the anticoagulant containing 5 μM 2ClAd. It is suggested that ADP released from the red blood cells is responsible for the increased platelet aggregability with the time after venepuncture and makes a serious contribution to the artifacts of in vitro platelet function studies.

Multiple electrode aggregometry: A new device to measure platelet aggregation in whole blood

2006 ◽  
Vol 96 (12) ◽  
pp. 781-788 ◽  
Author(s):  
Andreas Calatzis ◽  
Sandra Penz ◽  
Hajna Losonczy ◽  
Wolfgang Siess ◽  
Orsolya Tóth
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Blood Platelet ◽  
Platelet Inhibition ◽  
New Device ◽  
Platelet Aggregometry ◽  
Spontaneous Platelet Aggregation ◽  
Induced Aggregation ◽  
Blood Platelet Aggregation ◽  
Multiple Electrode

SummarySeveral methods are used to analyse platelet function in whole blood. A new device to measure whole blood platelet aggregation has been developed, called multiple electrode platelet aggregometry (MEA). Our aim was to evaluate MEA in comparison with the single platelet counting (SPC) method for the measurement of platelet aggregation and platelet inhibition by aspirin or apyrase in diluted whole blood. Platelet aggregation induced by different concentrations of ADP, collagen and TRAP-6 and platelet inhibition by apyrase or aspirin were determined in citrateor hirudin-anticoagulated blood by MEA and SPC. MEA indicated that spontaneous platelet aggregation was lower, and stimulated platelet aggregation was higher in hirudin- than citrate-anticoagulated blood. In hirudin-anticoagulated, but not citrate-anticoagulated blood, spontaneous platelet aggregation measured by MEA was inhibited by apyrase. For MEA compared with SPC the dose response-curves of agonist-induced platelet aggregation in citrate- and hirudin-blood showed similar EC50 values for TRAP, and higher EC50 values for ADP (non-significant) and collagen (p<0.05). MEA and the SPC method gave similar results concerning platelet-inhibition by apyrase and aspirin. MEA was more sensitive than SPC to the inhibitory effect of aspirin in collagen-induced aggregation. In conclusion, MEA is an easy, reproducible and sensitive method for measuring spontaneous and stimulated platelet aggregation, and evaluating antiplatelet drugs in diluted whole blood. The use of hirudin as an anticoagulant is preferable to the use of citrate. MEA is a promising technique for experimental and clinical applications.

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.

BERNARD-SOULIER SYNDROME: WHOLE BLOOD DIAGNOSTIC ASSAYS OF PLATELETS

1987 ◽  
Author(s):  
W L Nichols ◽  
S E Kaese ◽  
D A Gastineau ◽  
L A Otteman ◽  
E J W Bowie
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Blood Platelet ◽  
Laboratory Diagnosis ◽  
Light Transmittance ◽  
Immunocytochemical Staining ◽  
Platelet Glycoprotein ◽  
Giant Platelets ◽  
Bernard Soulier Syndrome

Diagnosis of Bernard-Soulier syndrome (BSS) is complicated by the difficulty of separating the giant platelets from other blood cells to pursue analyses of platelet function and structure. We report on the utility of three whole blood assay techniques for diagnosis of a patient with BSS. To our knowledge, these three techniques have not been simultaneously applied or compared for efficacy in laboratory diagnosis of BSS. (1) Whole blood platelet aggregation responses, studied with an electrical impedence aggregometer, were equivalent to those more laboriously obtained using platelet-rich plasma prepared by unit gravity sedimentation, studied with an optical light transmittance aggregometer. Platelet aggregation responses were normal with ADP or collagen stimulation, and absent with Ristocetin or bovine plasma stimulation. (2) Whole blood radioimmunoassay of platelet glycoprotein (GP) expression was performed using iodinated murine monoclonal antibodies HP1-1D (anti-GP IIb/IIIa) and 6D1 (anti-GPlb, kindly supplied by Dr. Barry Coller, Stony Brook, NY). After incubation with citrated whole blood, centrifugation was used to separate cell-bound antibody which was quantitated with a gamma counter. The patient’s whole blood had a normal level of cell-bound GP Ilb/IIIa, but a markedly reduced level of cell-bound GP lb (5% of normal mean; n = 20). (3) Whole blood smear immunocytochemical staining with the monoclonals (indirect immuno-alkaline phosphatase technique), and qualitative analysis by light microscopy, revealed a marked reduction of GP lb expression by the patient’s giant platelets, whereas GP Ilb/IIIa expression was normal. This latter technique might be especially valuable as a screening technique when the patient is not directly available for laboratory study. Together with the patient’s life-long history of thrombocytopenia and moderate bleeding diathesis, and other laboratory observations including markedly prolonged bleeding times and reduced whole blood prothrombin consumption, these data established diagnosis of BSS. We conclude that these three relatively simple assays of platelets in whole blood should be of particular value in the laboratory differential diagnosis of patients with congenital thrombocytopenias and giant platelet syndromes.

scholarly journals Spontaneous Platelet Aggregation and Sulfinpyrazone Influence in Patients with Diseases of the Kidneys and Hypertension

1977 ◽  
Author(s):  
W. Kirch ◽  
H. Köhler
Keyword(s):  
Essential Hypertension ◽  
Platelet Aggregation ◽  
Serum Creatinine ◽  
Chronic Glomerulonephritis ◽  
Thrombin Time ◽  
Plasmatic Coagulation ◽  
Spontaneous Aggregation ◽  
Spontaneous Platelet Aggregation ◽  
Almost All ◽  
Aggregation Of Platelets

In some diseases, particularly in diseases of the vessels, there is a spontaneous aggregation of platelets. So it was of interest, whether in patients with diseases of the kidneys and essential hypertension there is a frequent spontaneous aggregation as well. In addition, the effect of the antithrombotic substance sulfinpyrazone on platelet aggregation, on plasmatic coagulation and on clinical parameters, for instance on proteinuria, was to be investigated. In 47 patients with diseases of the kidneys or essential hypertension spontaneous platelet aggregation, thrombin time, partial thromboplastin time, fibrinogen and factor VIII were studied. Patients with spontaneous platelet aggregation were given 800 mg sulfinpyrazone daily for I to 6 months. In 15 of 16 patients with chronic glomerulonephritis (serum creatinine 0,7-2,0 mg%) and 13 of 14 patients with a chronic pyelonephritis (serum creatinine 0,8–1,7 mg%) spontaneous platelet aggregation was found as well. So in almost all patients with chronic glomerulonephritis and pyelonephritis a spontaneous aggregation was seen. The frequency of spontaneous platelet aggregation in patients with essential hypertension is likely to depend on the stage of hypertension. Spontaneous platelet aggregation did not return to normal in any of our patients on sulfinpyrazone and the substance had no influence on proteinuria, haematuria and leukocyturia in patients with diseases of the kidneys.

COMPARISON OF THE EFFECT OF ASPIRIN (ASA) AND CHOLINE MAGNESIUM TRISALICYLATE (CMT) ON PLATELET AGGREGATION IN WHOLE BLOOD EX-VIVO

1987 ◽  
Author(s):  
B J Z Danesh ◽  
A R Saniabadi ◽  
R I Russell ◽  
G D O Lowe ◽  
C D Forbes
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Therapeutic Potential ◽  
Ex Vivo ◽  
Random Order ◽  
Blood Platelet ◽  
Bleeding Complications ◽  
Double Blind ◽  
Inhibition Of Platelet Aggregation ◽  
Spontaneous Aggregation

Suppression of platelet aggregation by ASA limits the therapeutic use of this drug as an analgesic in patients with bleeding tendencies. CMT is a non-acetylated salicylate derivative with analgesic and anti-inflammatory effect similar to that of ASA. We compared platelet aggregation in human whole blood ex-vivo, three hours after ingestion of ASA and. CMT. Using a whole blood platelet counter, platelet aggregation was quantified by measuring the fall in the number of single platelets at peak aggregation in response to collagen (lμg/ml) arachidonic acid (AA, 0.5 mM) as well as spontaneous aggregation. In double blind and random order, 12 healthy volunteers received a single oral dose of ASA and CMT containing 500 mg equivalent salicylate, on two separate occasions, 10 days apart. Despite a comparable absorption of salicylic acid from the two drugs, ingestion of ASA resulted in a marked inhibition of platelet aggregation induced by collagen, AA and spontaneous aggregation, whereas such effects were not observed after CMT ingestion.We suggest that CMT may have therapeutic potential as an alternative to aspirin when inhibition of platelet aggregation can induce bleeding complications.

Effects of Lead Acetate on Platelet Aggregation, Ultrastructure and Serotonin Release

1971 ◽  
Vol 26 (03) ◽  
pp. 455-466 ◽  
Author(s):  
R. B Davis ◽  
G. C Holtz
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Lead Acetate ◽  
Platelet Rich Plasma ◽  
Adenosine Diphosphate ◽  
Blood Platelet ◽  
Human Platelets ◽  
Serotonin Release ◽  
Aggregation Of Platelets

SummaryThe effects of lead on blood platelet function and ultrastructure have been investigated. Lead acetate was injected intravenously in 27 rats and was added to rat and human platelet rich plasma in vitro. In vitro studies showed that concentrations of 2.5 × 10-3 M lead acetate reduced or blocked aggregation of rat and human platelets by adenosine diphosphate, collagen, and thrombin. Radioactive serotonin release from human platelets was inhibited by 10-4 M lead acetate. One hour after the injection of lead, platelet aggregation by thrombin was reduced, but platelet aggregation by adenosine diphosphate and collagen showed little change. Three days after lead, aggregation of platelets by collagen and thrombin was blocked and aggregation by adenosine diphosphate reduced. Thrombocytopenia was present 4 days after intravenous lead acetate. Electron micrographs of platelets showed that the mean number of mitochondria per platelet was increased, whereas alpha granules were reduced. Dense bodies were not significantly changed. Lead acetate affects platelet function in concentrations reported in human bone marrow in lead poisoning, and may relate to the binding of free sulfhydryl groups by lead.

Platelet Aggregation in Whole Blood Determined Using the Ultra-Flo 100 Platelet Counter

1982 ◽  
Vol 48 (03) ◽  
pp. 327-329 ◽  
Author(s):  
S C Fox ◽  
M Burgess-Wilson ◽  
S Heptinstall ◽  
J R A Mitchell
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Adenosine Diphosphate ◽  
Blood Platelet

SummaryThe Ultra-Flo 100 Whole Blood Platelet Counter has proved a useful tool for measuring platelet aggregation in whole blood, the extent of aggregation being deduced from the number of single platelets that remain. The technique has allowed us to show that platelets aggregate spontaneously in citrated blood and in heparinized blood but not in whole blood collected into EDTA. The aggregation occurs during storage but its rate is enhanced by stirring and it occurs more readily when the whole blood has been exposed to plastic rather than glass. It occurs much more readily in whole blood from some individuals than from others and the process may involve adenosine diphosphate (ADP). The rate of aggregation in whole blood is enhanced by several aggregating agents including collagen, ADP and sodium arachidonate which are more usually studied in platelet-rich plasma.

Comparison of Rapid Platelet Function Assay with Whole Blood Platelet Impedance Aggregometry for the Definition of Aspirin Resistance.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4018-4018
Author(s):  
Anna M. Dyszkiewicz-Korpanty ◽  
Anne Kim ◽  
James D. Burner ◽  
Eugene P. Frenkel ◽  
Ravindra Sarode
Keyword(s):  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Platelet Function ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Blood Platelet ◽  
Aspirin Resistance ◽  
Impedance Aggregometry ◽  
Definition Of ◽  
Induced Aggregation

Abstract The reported incidence of aspirin (ASA) resistance ranges from 5 to 30%. Various platelet function assays have been employed to detect aspirin resistance in patients with cardio- and cerebrovascular disease. Such a high proposed incidence of ASA resistance poses a critical need for a rapid point-of -care (POC) platelet function test. Unfortunately, no uniformly accepted definition of ASA resistance exists. Platelet aggregation studies that have been used to define ASA resistance are time consuming and require special technical expertise. The Ultegra Rapid Platelet Function -ASA (RPFA-ASA) has been developed as a POC test that is performed without sample processing. This optical method measures agglutination of fibrinogen-coated beads upon platelet activation with arachidonic acid. In the presence of aspirin effect, however, the agglutination of the beads is inhibited. The described cutoff of ≥ 550 Aspirin Reaction Units (ARU) is termed non-responsiveness to ASA based on a preclinical study and subsequent correlation with epinephrine-induced platelet aggregation in platelet rich plasma. Since RPFA-ASA uses whole blood, we validated its performance characteristics against a classic whole blood platelet aggregation assay (WBA). We studied 50 healthy volunteers, aged 25–75 (24 men, 26 women) with normal CBC, who had not ingested anti-platelet drugs for 14 days prior to the study. Baseline studies included WBA (dual channel aggregometer, Chrono-log Inc., Havertown, PA) using both arachidonic acid (AA -0.5; 0.25 mM) and collagen (1; 2 μg/mL) as well as an RPFA-ASA assay (Accumetrics Inc., San Diego, CA). These studies were repeated after 3 days of ASA (325 mg/d) intake. Based on a review of the literature, we defined an adequate ASA response as a completely inhibited AA-induced platelet aggregation and at least 30% inhibition of collagen-induced aggregation (both concentrations of the agonist). Thus, those with &lt; 30% inhibition of aggregation response to collagen were considered ASA resistant. Eleven subjects were ASA resistant by WBA (20%; 8 females and 3 males (aged 25–63). In contrast, since all 50 subjects achieved ARU values of &lt; 550 ARU, none were recognized as an ASA non-responder by the RPFA-ASA. While the current cutoff of &lt; 550 ARU posed by the Ultegra RPFA-ASA does identify those who have taken ASA, the assay is unable to recognize ASA non-responders. Thus, based on these data, the appropriate cutoff for the recognition of ASA resistance by the RPFA-ASA should be re-adjusted to a significantly lower level to ensure appropriate assay results.

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