Comparison of different anticoagulant associations on haemostasis and biochemical analyses in feline blood specimens

2016 ◽  
Vol 19 (4) ◽  
pp. 394-402 ◽  
Author(s):  
Fanny Granat ◽  
Céline Monzali ◽  
Elisabeth Jeunesse ◽  
Maud Guerlin ◽  
Catherine Trumel ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Divalent Cations ◽  
A Priori ◽  
Clinical Pathology ◽  
Reference Intervals ◽  
Poor Correlation ◽  
Aminotransferase Activity ◽  
Plasma Coagulation ◽  
Blood Specimens

Objectives Universal anticoagulant could be an alternative to the multiple blood sampling required for clinical pathology investigations in cats. An association of citrate, theophylline, adenosine and dipyridamole (CTAD) has been reported to be a good substitute for EDTA for haematology analysis in cats, limiting platelet clumping, and has also been shown to be valid for haematology, secondary haemostasis and some biochemical variables in humans. The aim of the study was therefore to investigate the effects of CTAD on in vitro platelet aggregation and compare results of secondary haemostasis and biochemistry tests, excluding a priori those variables not reliably measured in CTAD, such as sodium, chloride and divalent cations, in feline blood specimens collected in CTAD and paired citrate and heparin tubes. Methods Thirty blood specimens sampled in citrate and CTAD were analysed for in vitro platelet aggregation, and 60 blood specimens sampled in citrate or heparin and CTAD were analysed for plasma coagulation and a biochemistry panel. Results In vitro platelet aggregation was inhibited in CTAD compared with citrate specimens. Prothrombin time, activated partial thromboplastin time, antithrombin and fibrinogen results were similar, despite some significant differences. Measurements of triglycerides, cholesterol, glucose, urea, creatinine, phosphate, total proteins and alanine aminotransferase activity were similar and well correlated in CTAD and heparin plasmas, despite some significant differences and moderate biases. Albumin showed a marked positive proportional bias, and creatine kinase and alkaline phosphatase activities a moderate and marked negative mixed bias, respectively, but could be measured in CTAD if new reference intervals were calculated. Aspartate aminotransferase activity showed a marked negative proportional bias, along with a poor correlation and some clinical misclassifications just like the potassium concentration, and thus cannot be recommended to be measured in CTAD specimens. Conclusions and relevance In cats, CTAD cannot be used for primary haemostasis investigation but could be a suitable (almost) universal anticoagulant for routine haematology, as well as for plasma coagulation and many biochemistry variables.

The effect of dermatan sulfate on in vitro human plasma coagulation, platelet aggregation and βTG/PF4 release

1990 ◽  
Vol 57 (3) ◽  
pp. 405-414 ◽  
Author(s):  
E. Cofrancesco ◽  
M. Colombi ◽  
F. Gianese ◽  
M. Cortellaro
Keyword(s):  
Platelet Aggregation ◽  
Human Plasma ◽  
Dermatan Sulfate ◽  
Plasma Coagulation

Spontaneous Platelet Aggregation in Cerebrovascular Disease

1978 ◽  
Vol 39 (01) ◽  
pp. 223-229 ◽  
Author(s):  
J W Ten Cate ◽  
J Vos ◽  
H Oosterhuis ◽  
D Prenger ◽  
C S P Jenkins
Keyword(s):  
Platelet Aggregation ◽  
Cerebral Infarction ◽  
Clinical Symptoms ◽  
Divalent Cations ◽  
Normal Subjects ◽  
Transient Ischaemic Attacks ◽  
Refractory State ◽  
Spontaneous Platelet Aggregation ◽  
Aggregation Tendency

Summary50 patients from a group of 130 patients with transient ischaemic attacks or cerebral infarction were found to demonstrate in vitro spontaneous platelet aggregation (SPA) while 80 normal subjects tested never showed this phenomenon.The following additional findings point towards a possible platelet abnormality:1. Platelets from 10 patients with SPA when isolated and resuspended in normal plasma still demonstrated SPA while isolated normal platelets resuspended in patient’s plasma did not.2. Platelets demonstrating SPA showed an increased aggregation tendency upon incubation with ADP while normal platelets developed the expected refractory state.SPA was found to be dependant upon the presence of divalent cations and could further be inhibited by phentolamine and adenosine. Aspirin effectively abolished SPA in 50 patients and relieved the clinical symptoms of patients with recurrent complaints of transient blindness and paraesthesia.

scholarly journals In Vitro Spontaneous Platelet Aggregation in Cerebrovascular Disease

1977 ◽  
Author(s):  
J.W.ten Cate
Keyword(s):  
Platelet Aggregation ◽  
Room Temperature ◽  
Platelet Rich Plasma ◽  
Divalent Cations ◽  
Normal Range ◽  
Refractory State ◽  
Spontaneous Platelet Aggregation ◽  
Second Wave ◽  
Aggregation Tendency

Fifty patients from a group of 130 patients with transient ischemic attacks or cerebral infarction were found to demonstrate in vitro spontaneous platelet aggregation (SPA). This phenomenon occurred within 15 minutes when platelet-rich plasma samples (PRP) of these patients were stirred at 37°C in an aggregometer.In addition all patients showing SPA also demonstrated a lowthreshold concentration for the onset of ADP-induced second wave aggregation (ADP f.c. < 0.25 uM; normal range 0.75 + 0.2 uM). Of the remaining 80 patients 25 patients were found to be sensitive tolow concentrations of ADP.SPA remained present in samples of 8 patients studied when stored at room temperature for two hours. SPA was found to be dependant upon the presence of divalent cations and could be prevented by adenosine, phentolamine and aspirin. The following additional findings point towards a possible platelet defect:1. Platelets from 10 patients with SPA when isolated and resuspended in normal plasma still demonstrated SPA while isolated normal platelets in patients did not.2. Platelets demonstrating SPA showed an increased aggregation tendency upon incubation with ADP while normal platelets developed the expected refractory state for ADP.

Factors that Contribute to Spontaneous Platelet Aggregation and Streptokinase-Induced Aggregation in Whole Blood

1995 ◽  
Vol 73 (02) ◽  
pp. 297-303 ◽  
Author(s):  
Ruth Armstrong ◽  
Jane A May ◽  
Wolfgang Lösche ◽  
Stan Heptinstall
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Divalent Cations ◽  
High Concentration ◽  
No Donor ◽  
Rgd Sequence ◽  
Spontaneous Platelet Aggregation ◽  
Adhesive Proteins ◽  
Induced Aggregation

SummaryWhen whole blood is stirred there is a “spontaneous” platelet aggregation (SPA) which is presumed to be caused by proaggregatory factors released from platelets and other blood cells. Adding streptokinase (SK) to stirred whole blood frequently increases the rate and extent of the platelet aggregation that occurs; this is likely to be via immune complex formation between SK and natural anti-SK antibodies leading to increased release of pro-aggregatory factors.In this investigation we have examined the effects of several inhibitors and antagonists in an attempt to identify the proaggregatory factors that contribute to both SPA and SK-induced aggregation (SKA) and to evaluate different means of inhibiting both processes. The effects of the inhibitors/antagonists were determined in vitro after adding them to citrated whole blood obtained from healthy volunteers. Platelet aggregation was measured using a platelet counting technique.Inhibition of both SPA and SKA by apyrase and by FPL 66096 (a P2T receptor antagonist) demonstrated the involvement of ADP in both processes. Inhibition by chlorpromazine indicated that the most likely source of the ADP is red cells. The effects of sulotroban (a TXA2 antagonist) indicated involvement of TXA2 in SKA but not in SPA. The lack of effect of specific antagonists at S2, α2 and PAF receptors suggested lack of involvement of serotonin, catecholamines and plateletactivating factor in either SPA or SKA. Both SPA and SKA were potently inhibited by low concentrations of iloprost (a PGI2 analogue), but a high concentration of SIN-1 (a NO donor) was much less effective. SPA and SKA were prevented by EDTA and by RGDS indicating the importance of divalent cations and of the RGD sequence in adhesive proteins in mediating the platelet aggregation that occurred.We also determined the effects on SPA and SKA of adding MgCl2 to whole blood. In this case we used blood containing hirudin as anticoagulant. MgCl2 (1 mM) appeared to delay the onset of SPA and markedly inhibited SKA.

Fibrinogen and von Willebrand Factor-Independent Platelet Aggregation: The Essential Roles of β3 Integrin, Thrombin, and Divalent Ca2+ Cations.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2651-2651
Author(s):  
Hong Yang ◽  
Adili Reheman ◽  
Pingguo Chen ◽  
Richard O. Hynes ◽  
John Freedman ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Divalent Cations ◽  
Receptor Activation ◽  
Thrombin Inhibitors ◽  
Thrombin Inhibitor ◽  
Thrombin Receptor ◽  
Type I ◽  
Β1 Integrins ◽  
Β3 Integrin

Abstract It has been documented that fibrinogen (Fg) is required for platelet aggregation. However, we recently found that platelet rich thrombi still formed in mice lacking either Fg (Fg−/−) or both Fg and vWF (Fg/vWF−/−) (Ni et al, JCI106:385–392, 2000). To explore the potential mechanisms of Fg/vWF-independent platelet aggregation, we studied platelet aggregation in vitro in platelet rich plasma (PRP). We found no platelet aggregation in Fg−/− or Fg/vWF−/− PRP induced by adenosine diphosphate (ADP) in the presence of anticoagulant reagents including divalent cation chelators (ACD, sodium citrate, and EDTA), and thrombin inhibitors (heparin, hirudin, PPACK). Since no fibrin formation occurs in Fg/vWF−/− plasma, we then induced Fg/vWF−/− platelet aggregation in non-anticoagulated platelet poor plasma (PPP). Surprisingly, robust aggregation occurred after ADP treatment. We further demonstrated that directly triggering the thrombin receptor PAR4 with thrombin receptor activation peptide (TRAP, AYPGKF-NH2) induced platelet aggregation in thrombin-inhibitor treated Fg/vWF−/− PRP and gel-filtered Fg/vWF-platelets in 1mM Ca2+ PIPES buffer. Thus Fg/vWF-independent aggregation can be induced in vitro and both divalent cations and thrombin are required for this novel platelet aggregation pathway. It is likely that ADP induced thrombin generation in Fg/vWF-/- PRP. Considering platelet aggregation has been observed in type I Glanzmann Thrombasthenic patients lacking αIIbβ3 protein, we hypothesized that Fg/vWF−/− platelet aggregation may occur in either a β3 integrin-dependent or β3 integrin independent manners. To test this hypothesis, β3 integrin deficient (β3−/−) platelets were added into the same non-anticoagulated Fg/vWF−/− plasma and no aggregation was observed after ADP treatment. β3−/− platelets also did not co-aggregate with Fg/vWF−/− platelets in vitro in aggregation assays, which were analyzed by flow cytometry with an anti-CD61 (anti-β3 integrin) antibody. Furthermore, when fluorescently labeled β3−/− platelets were injected into Fg/vWF−/− mice, β3−/− platelets did not significantly incorporate into Fg/vWF−/− thrombi under confocal intravital microscopy. The inability of β3−/− platelets to aggregate is not due to a deficiency in other adhesive receptors, since no reduction of GPIbα, β1 integrins, and P-selectin was observed on β3−/− platelets. Thus, although the GPIb complex, P-selectin, and β1 integrins may be involved in platelet aggregation, β3 integrin is essential for this Fg/vWF-independent platelet aggregation pathway. This also indicates that other alternative ligands of β3 integrin from either the plasma or platelet granules are capable of mediating platelet aggregation independent of both Fg and vWF under more physiologically relevant conditions (i.e. non anti-coagulated blood) where divalent cations and thrombin are present.

Effect of Temperature on ADP-Induced Platelet Aggregation

1973 ◽  
Vol 29 (01) ◽  
pp. 183-189
Author(s):  
C. A Praga ◽  
E. M Pogliani
Keyword(s):  
Platelet Aggregation ◽  
Incubation Period ◽  
Room Temperature ◽  
Important Variable ◽  
Practical Significance ◽  
Effect Of Temperature ◽  
Induce Platelet Aggregation ◽  
Cuvette Holder ◽  
Exact Temperature

SummaryTemperature represents a very important variable in ADP-induced platelet aggregation.When low doses of ADP ( < 1 (μM) are used to induce platelet aggregation, the length of the incubation period of PRP in the cuvette holder of the aggregometer, thermostatted at 37° C, is very critical. Samples of the same PRP previously kept at room temperature, were incubated for increasing periods of time in the cuvette of the aggregometer before adding ADP, and a significant decrease of aggregation, proportional to the length of incubation, was observed. Stirring of the PRP during the incubation period made these changes more evident.To measure the exact temperature of the PRP during incubation in the aggre- gometer, a thermocouple device was used. While the temperature of the cuvette holder was stable at 37° C, the PRP temperature itself increased exponentially, taking about ten minutes from the beginning of the incubation to reach the value of 37° C. The above results have a practical significance in the reproducibility of the platelet aggregation test in vitro and acquire particular value when the effect of inhibitors of ADP induced platelet aggregation is studied.Experiments carried out with three anti-aggregating agents (acetyl salicyclic acid, dipyridamole and metergoline) have shown that the incubation conditions which influence both the effect of the drugs on platelets and the ADP breakdown in plasma must be strictly controlled.

Enhancement of ADP-induced Platelet Aggregation by Adrenaline in Vivo and Its Prevention

1973 ◽  
Vol 29 (02) ◽  
pp. 490-498 ◽  
Author(s):  
Hiroh Yamazaki ◽  
Itsuro Kobayashi ◽  
Tadahiro Sano ◽  
Takio Shimamoto
Keyword(s):  
Platelet Count ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
The Other ◽  
Endothelial Surface ◽  
Important Interaction ◽  
Blood Coagulability ◽  
The Difference

SummaryThe authors previously reported a transient decrease in adhesive platelet count and an enhancement of blood coagulability after administration of a small amount of adrenaline (0.1-1 µg per Kg, i. v.) in man and rabbit. In such circumstances, the sensitivity of platelets to aggregation induced by ADP was studied by an optical density method. Five minutes after i. v. injection of 1 µg per Kg of adrenaline in 10 rabbits, intensity of platelet aggregation increased to 115.1 ± 4.9% (mean ± S. E.) by 10∼5 molar, 121.8 ± 7.8% by 3 × 10-6 molar and 129.4 ± 12.8% of the value before the injection by 10”6 molar ADP. The difference was statistically significant (P<0.01-0.05). The above change was not observed in each group of rabbits injected with saline, 1 µg per Kg of 1-noradrenaline or 0.1 and 10 µg per Kg of adrenaline. Also, it was prevented by oral administration of 10 mg per Kg of phenoxybenzamine or propranolol or aspirin or pyridinolcarbamate 3 hours before the challenge. On the other hand, the enhancement of ADP-induced platelet aggregation was not observed in vitro, when 10-5 or 3 × 10-6 molar and 129.4 ± 12.8% of the value before 10∼6 molar ADP was added to citrated platelet rich plasma (CPRP) of rabbit after incubation at 37°C for 30 second with 0.01, 0.1, 1, 10 or 100 µg per ml of adrenaline or noradrenaline. These results suggest an important interaction between endothelial surface and platelets in connection with the enhancement of ADP-induced platelet aggregation by adrenaline in vivo.

LY53857, a 5HT2 Receptor Antagonist, Delays Occlusion and Inhibits Platelet Aggregation in a Rabbit Model of Carotid Artery Occlusion

1991 ◽  
Vol 66 (03) ◽  
pp. 355-360 ◽  
Author(s):  
Harve C Wilson ◽  
William Coffman ◽  
Anne L Killam ◽  
Marlene L Cohen
Keyword(s):  
Electrical Stimulation ◽  
Platelet Aggregation ◽  
Carotid Artery ◽  
Receptor Antagonist ◽  
Artery Occlusion ◽  
Carotid Artery Occlusion ◽  
Rabbit Platelet ◽  
Rabbit Platelets ◽  
5Ht2 Receptor

SummaryThe present study was designed to evaluate the effectiveness of the ergoline 5HT2 receptor antagonist, LY53857 in a rabbit model of vascular arterial occlusion. LY53857 (1 and 10 εM) inhibited serotonin amplified platelet aggregation responses to threshold concentrations of ADP in rabbit platelets in vitro. LY53857 (1 εM) not only inhibited the serotonin component of rabbit platelet aggregation, but also inhibited in vitro aggregation induced by ADP (48.7 ± 16.7% inhibition), collagen (76.1 ± 15.9% inhibition) and U46619 (65.2 ± 12.3% inhibition). The effectiveness of this ergoline 5HT2 receptor antagonist in blocking aggregation to ADP, collagen and U46619 may be related to its ability to inhibit a serotonin component of platelet aggregation since rabbit platelets possess high concentrations of serotonin that may be released during aggregation produced by other agents. Based on the effectiveness of LY53857 to inhibit rabbit platelet aggregation, we explored the ability of LY53857 to extend the time to carotid artery occlusion in rabbits following electrical stimulation of the artery. Reproducible carotid artery occlusion was induced in rabbits by moderate stenosis coupled to arterial cross clamping, followed by electrical stimulation. With this procedure, occlusion occurred at 47.0 ± 7 min (n = 30) after initiation of the electrical stimulation. Animals pretreated with LY53857 (50 to 500 εg/kg i.v.) showed a delay in the time to carotid artery occlusion (at 100 εg/kg i.v. occlusion time extended to 164 ± 16 min). Furthermore, ex vivo platelet aggregation from animals treated with LY53857 (300 εg/kg i.v.) resulted in 40.5% inhibition of platelet aggregation in response to the combination of ADP (1 εM) and serotonin (1 εM). These studies document the ability to obtain reproducible arterial occlusion in the rabbit and showed that intravenously administered LY53857 prolonged the time to carotid artery occlusion. Prolongation of carotid artery occlusion time was accompanied by inhibition of serotonin-amplified ADP-induced aggregation in rabbit platelets, an effect observed both in vitro and ex vivo. Thus, the rabbit is a useful model for studying the effectiveness of 5HT2 receptor antagonists in prolonging vascular occlusion induced by insult of the carotid artery.

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.

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