Evaluation of Whole-Blood Lumiaggregation

1997 ◽  
Vol 3 (3) ◽  
pp. 190-195 ◽  
Author(s):  
John J. Podczasy ◽  
James Lee ◽  
Ivana Vucenik
Keyword(s):  
Platelet Aggregation ◽  
Dose Response ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Normal Population ◽  
Method Comparison ◽  
Atp Release ◽  
Blood Platelet ◽  
Second Phase ◽  
Blood Impedance

An evaluation of whole-blood lumiaggregation was conducted in a normal population. Platelet aggregation and adenosine triphosphate (ATP) secretion were monitored in a three-phase study that analyzed sample dilution, agonist dose response, and method comparison. In the first phase, the blood:saline ratio was varied; in the second phase, the concentration of the agonists was varied ; and in the last phase, a comparison of impedance aggregation and ATP release in whole blood to optical aggregation and ATP release in platelet-rich plasma (PRP) was performed. Five common platelet agonists— collagen, adenosine diphosphate (ADP), arachidonic acid, thrombin, and ristocetin—were used in this evaluation of the lumiaggregometer (Chrono-Log Corp., Havertown, PA, U.S.A.). The data revealed that the optimum blood:saline ratio for conducting platelet antigen studies is 1:1, although with some agonists other dilutions can be used. The agonist dose-response phase basically confirmed the manufacturer's concentration recommendations. Additionally, it was determined that platelet aggregation using the whole-blood impedance technique compared to the PRP optical method yielded similar information. Furthermore, the advantages of whole-blood impedance aggregation include its use in microsamples and more timely results due to minimal sample preparation. Key Words: Platelet aggregation—Lumiaggregation—Whole blood—Platelet-rich ptasma—ATP.

Endotoxin-Induced Platelet Activation in Human Whole Blood In Vitro

1988 ◽  
Vol 59 (03) ◽  
pp. 378-382 ◽  
Author(s):  
Gyorgy Csako ◽  
Eva A Suba ◽  
Ronald J Elin
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Human Platelet ◽  
Platelet Rich Plasma ◽  
Atp Release ◽  
Human Platelets ◽  
Lag Phase ◽  
Human Whole Blood ◽  
Dose Dependent

SummaryThe effect of purified bacterial endotoxin was studied on human platelets in vitro. In adding up to 1 μg/mL of a highly purified endotoxin, we found neither aggregation nor ATP release in heparinized or citrated human platelet-rich plasma. On the other hand, endotoxin at concentrations as low as a few ng/mL (as may be found in septic patients) caused platelet aggregation in both heparinized and citrated human whole blood, as monitored by change in impedance, free platelet count, and size. Unlike collagen, the platelet aggregation with endotoxin occurred after a long lag phase, developed slowly, and was rarely coupled with measurable release of ATP. The platelet aggregating effect of endotoxin was dose-dependent and modified by exposure of the endotoxin to ionizing radiation. Thus, the activation of human platelets by “solubilized” endotoxin in plasma requires the presence of other blood cells. We propose that the platelet effect is mediated by monocytes and/or neutrophils stimulated by endotoxin.

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.

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.

MEASURING WHOLE BLOOD PLATELET AGGREGATION AND ATP-RELEASE WITH A CHRONO-LOG WHOLE BLOOD LUMI-AGGREGOMETER: EFFECT OF STORAGE TIME OF BLOOD SAMPLES

1987 ◽  
Author(s):  
F C Sieders ◽  
A C v Houwelingen ◽  
G Hornstra
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Storage Time ◽  
Bleeding Time ◽  
Atp Release ◽  
Blood Platelet ◽  
Blood Samples ◽  
Before And After ◽  
Positive Correlations ◽  
Blood Platelet Aggregation

The influence of storing blood for either one or two hours after blood sampling, on whole blood platelet aggregation and ATP-release was measured with a Chrono-log whole blood lumi-aggregometer, in 21 healthy male volunteers. Storage of blood samples, gently revolving at 37 °C in an incubator for one hour, caused a significant increase in aggregation and release as compared with results obtained immediately after sampling. After two hours' storage, the values had returned to their initial levels.Significant positive correlations were seen between values obtained before and after storage of blood, and between various aggregation and release parameters. In this study, bleeding time nor hematocrit values were significantly correlated with the aggregation and release parameters. The considerable influence of storage time on whole blood platelet aggregation and ATP-release underlines the importance of performing these determinations immediately after sampling, or possibly after a standardized storage time. Otherwise, comparison of results -obtained either in clinical situations or in trials - will increase variability as a result of which false conclusions may be obtained. This will be illustrated in a small trial using paracetamol.

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.

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.

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 < 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 < 550 ARU, none were recognized as an ASA non-responder by the RPFA-ASA. While the current cutoff of < 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.

Platelet function in obese children and adolescents

2010 ◽  
Vol 30 (S 01) ◽  
pp. S126-S131 ◽  
Author(s):  
J. Schweigel ◽  
A. Naeke ◽  
MA. Lee-Kirsch ◽  
G. Siegert ◽  
S. Bergmann ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Atp Release ◽  
Normal Weight ◽  
Healthy Controls ◽  
Overweight Children ◽  
Obese Children ◽  
Prevalence Of Obesity ◽  
Platelet Hyperaggregability

SummaryPlatelet hyperaggregability contributes to thromboembolic events of obesity in adulthood. In obese children hyperaggregability was described in platelet rich plasma. We investigated platelet aggregation in children with obesity and lipometabolic disorders in whole blood. Patients, material, methods: Specimens from patients with overweight (n = 35), hypercholesterolaemia and normal weight (n = 5), overweight plus combined li-pometabolic disorder (n = 5) and healthy controls (n = 20) were investigated. Aggregation and ATP release were induced by ADP (20 μmol/l), collagen (1 μg/ml) and thrombin (0.5 U/ml) using a lumiaggregometer. Results: Overweight children and normal weight patients with hypercholesterolaemia exhibited no significant differences in platelet aggregation compared to controls. Contrastingly, in patients with obesity plus lipometabolic disorder the aggregation rate was significantly higher (p < 0.05) suggesting a hyperaggregable state. Conclusion: Obviously in obese children a hypercoagulable state exists and the slight hyperaggregability observed in whole blood in this cohort might contribute to that. Any effort should be undertaken to avoid obesity in children especially in those countries where the prevalence of obesity in childhood is continuously increasing.

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.

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