An instrument for measuring platelet aggregation by monitoring over time the changes in optic density of a platelet suspension treated with aggregating agents (ADP, collagen, epinephrine).
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PRP was allowed to stand at room temperature for 30 minutes Platelet aggregation was performed by turbidometric technique on Chronolog aggregometer by adding 10 um/ml Adenosine diphosphate (ADP) and 1.25 mg/ml Ristocetin and collagen 2 ug/ml, Epinephrine 10 um/ml in 250uL PRP in separate cuvettes.
The authors thank the Laboratory Roche Diagnostica Brasil LTDA for providing the multiple electrode impedance platelet aggregometer and the accompanying disposable materials, and Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq; grant # 3033 28/2013-4) and Fundacao de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ; grant #E-26/102.981/ 2011) for grants to E.
The collected samples were transported to Armed Forces Institute of Pathology (AFIP) where impedence aggregometer (Model 700, ChronoLog Corporation, Havertown, PA) was available18.
Past laboratory tests revealed normal platelet counts and morphology, prolonged bleeding times, clotting time of 4.15 minutes, decreased clot retraction (20%), and abnormal platelet aggregation responses to physiologic stimuli such as adenosine diphosphate and epinephrine used during the aggregometer study.
The research showed that the injection of 2 x [10.sup.-3] mol/l of Compound I into the aggregometer cuvet during 5 min of inductors makes platelet aggregation increase on average by 9.7% (P = 0.006) for ADP and 8.3% (P = 0.005) for collagen that two times exceeds etamsylate indicators.
Platelet reactivity ex vivo was assessed with a platelet-rich plasma (PRP) aggregometer using a ChronoLog after stimulating samples with collagen (2 [micro]g/ml), epinephrine (0.1 mmol/L), and adenosine diphosphate (ADP) (1 [micro]mol/L).
Aggregation was performed in platelet-rich plasma using a 2-channel optical aggregometer (Chrono-log 490-2D, Chrono-Log, Pennsylvania, USA), and platelet response to arachidonic acid with and without aspirin was tested simultaneously.
Platelet aggregation assays were performed as previously described [25] in human PRP and measured using the automatic Aggregometer 4 channels (AggRAM[TM] version 1.1; Helena Laboratories, USA).
I[C.sub.50] ([micro]L) values are expressed in microliters of initial volume of oil that induces 50% inhibition against 1 x [10.sup.-11] M PAF final concentration in the aggregometer cuvette.
The turbidimetric method was applied to measure platelet aggregation stimulated by the various kinds of agonists using an aggregometer [28].
Von Willebrand factor ristocetin cofactor (VWF: RCo) activity was measured with an in-house assay in a aggregometer (Chronolog Aggregometer 490) that measures the rate of aggregation of platelets in the presence of VWF and ristocetin.