Clopidogrel-herb Interactions: A Pharmacokinetic and Pharmacodynamic Assessment in a Rat Model.

BACKGROUND: Herbs usually contain a mixture of biologically active constituents, which can interact with numerous prescribed drugs and alter their safety profiles. OBJECTIVES: The current investigation was aimed to evaluate the effect of commonly used herbal products including black seed (Nigella sativa), garden cress (Lepidium sativum), and fenugreek (Trigonella foenum-graecum) on the pharmacokinetics and pharmacodynamics of clopidogrel using a Wistar rat model. METHODS: A GC-MS analysis revealed the presence of several phytoconstitutents (polyphenols) in the extracts of black seed, garden cress, and fenugreek. These polyphenols have the potential to interfere with clopidogrel effect. Plasma concentrations of clopidogrel were measured at different time points in the absence and presence of the concurrent use of tested herbal products and the pharmacokinetic parameters were calculated. Bleeding time was measured in various groups as a measure of the antiplatelet effect of clopidogrel. RESULTS: Area under the plasma concentration-time curves (AUC0-∞) of clopidogrel were 35.53 ±0.89 µg/ml*h (p<0.05), 26.01 ±0.90 µg/ml*h (p>0.05) and 32.80 ±2.51 µg/ml*h (p<0.05) in the black seed, garden cress and fenugreek group, respectively, compared with that of the control group (27.02 ±0.42 µg/ml*h). Treatment with black seed also caused an increase in clopidogrel Cmax by 31.52% (p<0.05) and with fenugreek by 21.42% (p<0.05); Cmax, did not changed with garden cress treatment (6.48 ±0.15 µg/ml versus 6.12 ±0.21 µg/ml, p>0.05). The pharmacodynamic evaluation of the antiplatelet effect of clopidogrel in the presence of herbal products treatment showed a significant prolongation in the bleeding time from a control baseline by ~22-26%, and by added ~8-12% in reference to clopidogrel therapeutic effect (p<0.05). CONCLUSION: The concurrent use of black seed, fenugreek, or garden cress can alter the pharmacokinetics and pharmacodynamics of clopidogrel to varying degrees due to the presence of various bioactive polyphenols. This is probably due to changes in drug disposition and its antiplatelet action. Further confirmation can determine the clinical relevance of these observations and identify the exact constituents responsible for such activities.

Mouse models of hemostasis.

Hemostasis is the normal process that produces a blood clot at a site of vascular injury. Mice are widely used to study hemostasis and abnormalities of blood coagulation because their hemostatic system is similar in most respects to that of humans, and their genomes can be easily manipulated to create models of inherited human coagulation disorders. Two of the most widely used techniques for assessing hemostasis in mice are the tail bleeding time (TBT) and saphenous vein bleeding (SVB) models. Here we discuss the use of these methods in the evaluation of hemostasis, and the advantages and limits of using mice as surrogates for studying hemostasis in humans.

Comparing coagulation activity of Selaginella tamariscina before and after stir-frying process and determining the possible active constituents based on compositional variation.

CONTEXT: Selaginella tamariscina (P. Beauv.) Spring (Selaginellaceae) (ST) has been widely used in China as a medicine for improving blood circulation. However, its processed product, S. tamariscina carbonisatus (STC), possesses opposite haemostatic activity. OBJECTIVE: To comprehensively evaluate the activity of ST and STC on physiological coagulation system of rats, and seek potential active substances accounting for the activity transformation of ST during processing. MATERIALS AND METHODS: The 75% methanol extracts of the whole grass (fine powder) of ST and STC were prepared, respectively. Male Sprague-Dawley rats were randomly divided into five groups: control group, model group, model + ST group, model + STC group and positive control group (model + Yunnanbaiyao). The duration of intragastric administration was 72 h at 12 h intervals. Haemorheology parameters were measured using an LB-2 A cone-plate viscometer and the existed classic methods, respectively. SC40 semi-automatic coagulation analyzer was employed to determine coagulation indices. Meanwhile, HPLC and LC-MS were applied for chemical analyses of ST and STC extracts. RESULTS: STC shortened tail-bleeding time, increased whole blood viscosity (WBV) and plasma viscosity (PV), decreased erythrocyte sedimentation rate blood (ESR), reduced activated partial thromboplastin time (APTT) and increased the fibrinogen (FIB) content in the plasma of bleeding model rats. Although ST could shorten APTT and TT, the FIB content was significantly decreased by ST. Dihydrocaffeic acid with increased content in STC vs. ST showed haemostatic activity for promoting the platelet aggregation induced by collagen and trap-6, and reducing APTT and PT significantly with a concentration of 171.7 µM in vitro. Amentoflavone with reduced content in STC vs. ST inhibited ADP and AA-induced platelet aggregation significantly with a concentration of 40.7 µM. DISCUSSION AND CONCLUSIONS: As the processed product of ST, STC showed strong haemostatic activity on bleeding rat through regulating the parameters involved in haemorheology and plasma coagulation system. Two active compounds, dihydrocaffeic acid and amentoflavone, might be partially responsible for the haemostatic and anticoagulant activity of STC and ST, respectively.

Identification of ITGA2B and ITGB3 Single-Nucleotide Polymorphisms and Their Influences on the Platelet Function.

The aim of the study was to investigate ITGA2B and ITGB3 genetic polymorphisms and to evaluate the variability in the platelet function in healthy Chinese subjects. The genetic sequence of the entire coding region of the ITGA2B and ITGB3 genes was investigated. Adenosine diphosphate-induced platelet aggregation, glycoprotein IIb/IIIa content, bleeding time, and coagulation indexes were detected. Thirteen variants in the ITGA2B locus and 29 variants in the ITGB3 locus were identified in the Chinese population. The rs1009312 and rs2015049 were associated with the mean platelet volume. The rs70940817 was significantly correlated with the prothrombin time. The rs70940817 and rs112188890 were related with the activated partial thromboplastin time, and ITGB3 rs4642 was correlated with the thrombin time and fibrinogen. The minor alleles of rs56197296 and rs5919 were associated with decreased ADP-induced platelet aggregation, and rs55827077 was related with decreased GPIIb/IIIa per platelet. The rs1009312, rs2015049, rs3760364, rs567581451, rs7208170, and rs117052258 were related with bleeding time. Further studies are needed to explore the clinical importance of ITGA2B and ITGB3 SNPs in the platelet function.

Anti-platelet and anti-thrombotic effect of a traditional herbal medicine Kyung-Ok-Ko.

ETHNOPHARMACOLOGICAL RELEVANCE: Kyung-Ok-Ko (KOK), a traditional herbal prescription, contains six main ingredients; Rehmannia glutinosa var. purpurae, Lycium chinense, Aquillaria agallocha, Poria cocos, Panax ginseng, and honey. KOK has been widely taken as a traditional oriental medicine for improving blood circulation or age-related symptoms, such as dementia and stroke. However, the effect of KOK on platelet activity has not been clarified. MATERIALS AND METHODS: To evaluate the effect of KOK on platelet function, we evaluated its effect on functional markers of platelet activation such as aggregation and shape change. As a mechanism study for the effect of KOK, we examined its effect on granule secretion, intracellular Ca(2+) increase, and PLCγ and Akt activation. To investigate the effect of orally administered KOK (0.5, 1, 2 g/kg), we examined its ex vivo effect on platelet aggregation in rat, and its in vivo anti-thrombotic effect in mice thromboembolism model. Furthermore, the effect of KOK on bleeding time was examined to estimate its potential side effect. RESULTS: KOK (0.3, 1, 3, 10 mg/ml) inhibited collagen-induced platelet aggregation and shape change in rat platelets in a concentration-dependent manner. The mechanism for the anti-platelet effect of KOK seems to involve the inhibition of ATP release, intracellular Ca(2+) elevation, and the phosphorylation of PLCγ and Akt. In rat ex vivo study, KOK (2 g/kg, p.o. for 1 day, and 0.5, 1, 2 g/kg, p.o. for 7 days) also had significant inhibitory effects on collagen-induced platelet aggregation. In addition, KOK showed a significant protective effect against thrombosis attack in mice. The prolongation of bleeding time by KOK was much less than that by ASA, suggesting a beneficial potential of KOK than ASA in view of side effect. CONCLUSIONS: These findings suggest that KOK elicits remarkable anti-platelet and anti-thrombotic effects with less side effect of bleeding, and therefore, it may have a therapeutic potential for the prevention of platelet-associated cardiovascular diseases.

Comparison of microporous polysaccharide hemospheres and Ankaferd Blood Stopper in a rabbit epistaxis model.

The aim of this study was to evaluate the histopathological impact, effectiveness, and safety of two hemostatic agents, Ankaferd Blood Stopper (ABS) and microporous polysaccharide hemospheres (MPH), in an experimental rabbit epistaxis model. Rabbits were randomly assigned, using a computerized random number generator, to the following three groups of six animals: group 1 (control, irrigated with saline); group 2 (ABS-treated); and group 3 (MPH-treated). In all groups, a standardized rabbit epistaxis model was used. Hemostasis time and extent of nasal bleeding were measured to compare the hemostatic effect of ABS and MPH among groups. Septums were removed for histopathological analysis, 7 days after the procedure. ABS reduced hemostasis time to 104.2 s and amount of bleeding to 20.5 mg. MPH reduced hemostasis time to 71.7 s and amount of bleeding to 11.5 mg. Mean bleeding time in wounds administered ABS and MPH was significantly shorter compared with wounds administered isotonic saline solution (p = 0.004). ABS and MPH application decreased bleeding significantly compared with the control group (p = 0.004). Bleeding time and amount in the MPH group was significantly reduced compared with the ABS group (p = 0.013 and p = 0.004, respectively). There was no significant difference in the histopathological evaluation results between the ABS, MPH, and control groups. Our data indicate that both ABS and MPH represent safe, effective, and fast-acting hemostatic agents in the management of epistaxis. MPH was more effective than ABS in terms of hemostasis time and amount of bleeding.

Comentarios al artículo «Tratamiento anestesiológico de la fractura de pelvis "en libro abierto" secundaria a explosión» / Comment on article «Anesthesiology treatment of an "open book" pelvic fracture due to an explosión»

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Effects of increased von Willebrand factor levels on primary hemostasis in thrombocytopenic patients with liver cirrhosis.

In patients with liver cirrhosis procoagulant and anticoagulant changes occur simultaneously. During primary hemostasis, platelets adhere to subendothelial structures, via von Willebrand factor (vWF). We aimed to investigate the influence of vWF on primary hemostasis in patients with liver cirrhosis. Therefore we assessed in-vitro bleeding time as marker of primary hemostasis in cirrhotic patients, measuring the Platelet Function Analyzer (PFA-100) closure times with collagen and epinephrine (Col-Epi, upper limit of normal ≤ 165 s) or collagen and ADP (Col-ADP, upper limit of normal ≤ 118 s). If Col-Epi and Col-ADP were prolonged, the PFA-100 was considered to be pathological. Effects of vWF on primary hemostasis in thrombocytopenic patients were analyzed and plasma vWF levels were modified by adding recombinant vWF or anti-vWF antibody. Of the 72 included cirrhotic patients, 32 (44.4%) showed a pathological result for the PFA-100. They had mean closure times (± SD) of 180 ± 62 s with Col-Epi and 160 ± 70 s with Col-ADP. Multivariate analysis revealed that hematocrit (P = 0.027) and vWF-antigen levels (P = 0.010) are the predictors of a pathological PFA-100 test in cirrhotic patients. In 21.4% of cirrhotic patients with platelet count ≥ 150/nL and hematocrit ≥ 27.0%, pathological PFA-100 results were found. In thrombocytopenic (< 150/nL) patients with cirrhosis, normal PFA-100 results were associated with higher vWF-antigen levels (462.3 ± 235.9% vs. 338.7 ± 151.6%, P = 0.021). These results were confirmed by multivariate analysis in these patients as well as by adding recombinant vWF or polyclonal anti-vWF antibody that significantly shortened or prolonged closure times, respectively. In conclusion, primary hemostasis is impaired in cirrhotic patients. The effect of reduced platelet count in cirrhotic patients can at least be partly compensated by increased vWF levels. Recombinant vWF could be an alternative to platelet transfusions in the future.

Reference values and repeatability of buccal mucosal bleeding time in healthy sedated cats.

Bleeding time is a screening test for the evaluation of primary haemostasis. As there is currently limited information on the reference interval (RI) and repeatability of the test in the cat compared with the dog, the purpose of the study was to establish the RI of buccal mucosa bleeding time (BMBT) in healthy cats and to investigate the intra-observer repeatability of the test. Fifty-six cats were prospectively enrolled in the study. The animals were deemed to be healthy based on history, physical examination, complete blood count, serum biochemistry, and negative serological testing for feline leukaemia and immunodeficiency viruses. All cats were sedated with ketamine, dexmedetomidine and morphine, and the BMBT was sequentially measured in the left and right exposed buccal mucosa following a standardised incision made by a commercially available, disposable, bleeding time device. The mean BMBT was 58.6 s and the RIs ranged from 34 to 105 s (Bootstrap estimation). The intra-observer repeatability was up to 87 s (Bland-Altman plot). The results of this study imply that the combination of ketamine, dexmedetomidine and morphine is a safe and useful sedative protocol allowing for the reliable measurement of BMBT in the cat. The RI of feline BMBT may range from 34 to 105 s and the BMBT may differ by up to 87 s for any two consecutive readings for an individual cat.

Current practices of bleeding time in a developing country: an alert for noncompliance with the standard procedures.

INTRODUCTION: Bleeding time is still widely performed in many developing countries including Thailand. To generate an accurate result, the procedure should be complied with standard recommendations such as those from Clinical and Laboratory Standards Institute (CLSI) and World Federation of Hemophilia (WFH). The authors surveyed the current practices of bleeding time in Thailand in order to verify the practices that did not comply with the accepted standard. METHODS: The questionnaires were sent to hospitals participating Thailand National External Quality Assessment Scheme (NEQAS) for blood coagulation. Items in the questionnaire comprised information about preanalytical, analytical, and postanalytical issues of bleeding time. RESULTS: From a dispatch of 201 questionnaires, 155 (77.1%) were returned. The common noncompliance with standards observed in this survey included inappropriateness of indication, e.g. use for preoperative screening (95 of 126, 75.4%), use of devices other than standard template (130 of 132, 98.5%), and inappropriate reference range (125 of 127, 98.4%). CONCLUSIONS: The noncompliance shown in this survey can affect the accuracy of bleeding time results. The authors would like to address these problems as an alert for other laboratories especially in the developing countries where the standard templates are not widely available.

Control de la hemorragia en el ámbito militar / Control of bleeding in the military environment

Uno de los pilares de la medicina militar es el control del shock hemorrágico. La hemorragia es la primera causa de muerte prevenible en combate, el control adecuado del sangrado se considera primordial para estimar la supervivencia del combatiente y, el apoyo terapéutico encaminado a minimizar la pérdida sanguínea supone un reto dentro la logística sanitaria militar. El objetivo del trabajo es revisar los avances médicos y logísticos en el tratamiento de la hemorragia en el ambiente militar a lo largo de los últimos conflictos, describir cuál está siendo la aportación de las Fuerzas Armadas Españolas y perfilar futuras líneas de investigación(AU)

One of the basics of military medicine is the control of haemorrhagic shock. Haemorrhage is the first cause of preventable death in combat, with the adequate control of bleeding being considered as fundamental to estimate the survival of the combatant as well as therapeutic support aimed at minimising blood loss being a challenge within military health logistics. The aim of this work is to review the medical and logistics advances in the treatment of bleeding in the military environment and combat during the latest conflicts, and to describe what is the current contribution of the Spanish Armed Forces and to profile future lines of investigation(AU)

Epistaxis: a contemporary evidence based approach.

This article provides a contemporary management protocol for adult epistaxis admissions, evidence based where possible, and otherwise based on the authors' own experience.

A polyclonal antibody against active C-terminal ADAMTS-18 fragment.

The human ADAMTS-18, a disintegrin and metalloproteinase with thrombospondin type-1 modules 18, is a secreted Zn-metalloproteinase. The C-terminal 385-amino acid fragment of ADAMTS-18 (AD18C) is highly effective at promoting platelet thrombus dissolution in vivo. Therefore, polyclonal antibody (pAb) against AD18C fragment should be able to keep platelet thrombus stability, which has direct clinical relevance. In this report, pAb against AD18C fragment was generated from rabbit immunized with AD18C recombinant protein (rAD18C). The pAb showed specific binding with rAD18C and natural ADAMTS-18 protein by ELISA and Western blot assay. It shortens the mouse tail bleeding time in a dose-dependent manner. Thus, anti-AD18C pAb contributes to the regulation of platelet thrombus stability.

New derivative of staphylokinase SAK-RGD-K2-Hirul exerts thrombolytic effects in the arterial thrombosis model in rats.

SAK-RGD-K2-Hir and SAK-RGD-K2-Hirul are recombinant proteins that are derivatives of r-SAK (recombinant staphylokinase). They are characterized by their fibrin-specific plasminogen activation properties and their antithrombin and antiplatelet activities. The difference between these proteins is the presence of the antithrombotic fragment (hirudin or hirulog) in the C-terminal portion of the r-SAK. The aim of the present study was to examine the thrombolytic potentials of SAK-RGD-K2-Hir and SAK-RGD-K2-Hirul in an electrically induced carotid artery thrombosis model in rats and to compare the potentials to that of r-SAK. We determined that a bolus injection of SAK-RGD-K2-Hirul was more effective than one of r-SAK in the improvement and maintenance of carotid patency and in arterial thrombus weight reduction; however, it had the same potency as SAK-RGD-K2-Hir. The bleeding time, prothrombin time and activated partial thromboplastin time were significantly prolonged in the animals that were treated with either dose (1.5 or 3.0 mg/kg) of SAK-RGD-K2-Hir or SAK-RGD-K2-Hirul, whereas no changes were observed in the plasma fibrinogen concentration or the α2 plasmin inhibitor level. r-SAK alone did not change the bleeding time or coagulation parameters. In conclusion, our findings demonstrate the thrombolytic activity of intravenous bolus injection of the novel thrombolytic agent SAK-RGD-K2-Hirul in rats. Although this protein compares favorably with r-SAK, we were unable to show the presence of any beneficial effects of SAK-RGD-K2-Hirul over those of SAK-RGD-K2-Hir. Furthermore, our results suggest that high doses of SAK-RGD-K2-Hirul bear the risk of bleeding.

Cáncer colorrectal: retraso diagnóstico. ¿Hemos mejorado algo en los últimos 25 años? / Colorectal cancer and its delayed diagnosis: have we improved in the past 25 years?

Objetivo: determinar la situación actual en cuanto al retraso diagnóstico del cáncer colorrectal (CCR) y analizar si se ha producido alguna mejora con respecto a lo acontecido hace 25 años en un mismo medio sanitario y con una misma metodología. Pacientes y método: se entrevistó personalmente a 152 pacientes durante su ingreso para tratamiento quirúrgico en nuestro Servicio con el fin de determinar el retraso acumulado para el diagnóstico y tratamiento de su CCR. Se realizó un análisis estadístico univariable y mutivariable mediante el software SPSS. Resultados: se incluyeron 152 pacientes con una edad media de 71 años con una desviación típica de 10 (edad mínima 36 y máxima 90 años), con un total de 82 varones y 70 mujeres (53,9 y 46,1% respectivamente; p > 0,05). El retraso diagnóstico del cáncer colorrectal en el momento actual en nuestro medio es de 7,28 meses, a pesar de que la mayoría de los pacientes cursa con sintomatología florida, como es la rectorragia en un 58% de pacientes. Aunque el retraso es menor que hace 25 años, la diferencia no llega a ser significativa en cuanto a retraso médico ni por parte del paciente (retraso médico 3,28 meses en 1985 frente a 1,89 en el momento actual y retraso del paciente de 3,18 en 1985 frente a 2,75 en la actualidad) (p > 0,05). A diferencia de lo que acontecía hace 25 años, no se ha encontrado relación entre retraso diagnóstico y estadio anatomopatológico, con el hecho paradójico de un menor retraso en estadio D (5,71 meses) que en A (11,16 meses) (p < 0,05). Conclusión: el retraso diagnóstico en el CCR es de 7,28 meses; cifra muy elevada para una patología que presenta sintomatología en el 90% de pacientes. En los últimos 25 años apenas ha variado el retraso global, aunque ha mejorado de forma importante el atribuible al médico. En nuestro estudio no se ha encontrado relación entre retraso diagnóstico y estadio anatomopatológico. Dada la alta prevalencia del cáncer colorrectal y la insuficiencia de las campañas para diagnóstico temprano del mismo en fase sintomática, con la ausencia de mejoría en cuanto al pronóstico, creemos necesaria la potenciación de programas de screening mediante colonoscopia(AU)

Objective: to determine the current delay in diagnosing colorectal cancer (CRC) and establish whether there has been any improvement n the past 25 years in the same healthcare setting using the same methods. Patients and method: 152 patients undergoing surgery at our unit were personally interviewed during their hospital stay to determine the delay incurred for the diagnosis and treatment of their CRC. SPSS software was used for univariate and multivariate analysis of the data obtained. Results: the study population was comprised of 152 patients of mean age 71 years (SD 10; range 36 to 90 years), 82 men and 70 women (53.9 and 46.1% respectively; p > 0.05). The diagnostic delay for CRC at our unit currently runs at 7.28 months despite the fact that in 58% of patients the disease produced obvious symptoms such as rectal bleeding. Although this delay in diagnosis is reduced over that observed 25 years ago, the difference is statistically not significant in terms of both doctor-attributed or patient-attributed delay (doctor-attributed delay was 3.28 months in 1985 versus 1.89 at present and patient-attributed delay was 3.18 months versus today’s 2.75; p > 0.05). Unlike the situation 25 years ago, no link was detected between diagnostic delay and tumor stage. Paradoxically, stage D disease was diagnosed earlier (at 5.71 months) than stage A disease (at 11.16 months) (p < 0.05). Conclusion: the diagnostic delay for CRC at our centre is 7.28 months. This delay is excessive for a disease that produces evident symptoms in 90% of patients. Over the last 25 years little improvement has been noted in the overall delay in diagnosing CRC, al - though the delay attributed to the care provider has significantly improved. No relationship was detected between diagnostic delay and disease stage upon diagnosis. We feel the high prevalence of CRC, the failure of campaigns to increase awareness of early symptoms and no real improvement in its prognosis justify the introduction of large-scale colonoscopy screening for this disease(AU)

Pharmacological profile of Salvadora persica.

This work was conducted to investigate the various pharmacological activities of Salvadora. persica family Salvadoracea and that includes anti inflammatory, analgesic, CNS, bleeding and clotting time activity by oral administration at the dose of 300 and 500mg/kg of body weight in animal models. Acute oral toxicity results showed that crude extract of S. persica is safe up to the dose of 5g/kg body weight of animals. Carraganeen induced hind paw edema method for anti inflammatory activity, tail immersion test method for analgesic activity, Rota rod and grip strength test for CNS activity were carried out in animal models. The analgesic activity was compared with aspirin, 300mg/kg body weight, anti inflammatory activity was compared with indomethacine, 10mg/kg body weight, Transamin 250mg/kg and Vitamin K 10mg were used for bleeding and clotting time activity respectively while diazepam 5mg/kg were used as standard for behavior and CNS activities. In all activities S. persica showed prolonged and dose dependent effects. Phytochemical analysis was also carried out which showed the presence of certain phytoconstituents which possesses these properties. Therefore the results justified the traditional use of the plant.

Platelet activity and cardiovascular risk in apparently healthy individuals: a review of the data.

Cardiovascular disease is a major cause of morbidity and mortality. Numerous risk scores exist to identify healthy individuals at increased risk of developing cardiovascular disease. Although platelets are a key mediator in the pathogenesis of cardiovascular disease, the role of platelet activity measurements and the incidence of cardiovascular disease are uncertain. Platelet aggregometry-the most well studied method of platelet function testing-is associated with risk factors for cardiovascular disease. However, data supporting platelet aggregation and incident cardiovascular disease is conflicting. Plasma markers of platelet activation are promising candidates. Soluble CD40L and P-selectin are easily measured with a standardized ELISA, and there is some data to suggest an association with cardiovascular disease, but further studies are required. While mean platelet volume is a promising candidate, platelet count and bleeding time are not specific for platelet activity nor are they associated with cardiovascular disease in a healthy population. For this field to progress, we recommend large-scale, prospective studies that measure a battery of these platelet function tests in individuals without cardiovascular disease to better understand the associations, if any, between platelet activity and cardiovascular disease.

Multiple electrode whole blood aggregometry, PFA-100, and in vivo bleeding time for the point-of-care assessment of aspirin-induced platelet dysfunction in the preoperative setting.

BACKGROUND: Acquired platelet dysfunction due to aspirin ingestion may increase bleeding tendency during surgery. Thus, we examined the diagnostic accuracy of in vivo bleeding time (BT) and 2 platelet function assays for the preoperative assessment of a residual antiplatelet effect in patients treated with aspirin. METHODS: Consecutive patients scheduled for surgery were prospectively enrolled in this study. The patients' last aspirin ingestion had occurred within the previous 48 hours before blood sampling in the "full aspirin effect" group, between 48 and 96 hours before in the "variable aspirin effect" group, and >96 hours before in the "recovered aspirin effect" group. The control group had not taken any aspirin. Multiple electrode aggregometry, platelet function analyzer (PFA)-100, and in vivo BT were performed to assess the effects of aspirin. One-way analysis of variance on ranks with a post hoc multiple-comparison procedure (Dunn) was used to detect differences among the groups. Categorical data were compared using the z test. Receiver operating characteristic (ROC) curves were created to determine the diagnostic accuracy of the platelet function assays investigated. The area under the ROC curve (AUC), sensitivity, and specificity of the assays were calculated. The level of statistical significance was set at P < 0.05. RESULTS: Three hundred ninety-four patients were included in the analysis (133 control and 261 aspirin-treated patients). All 3 methods were able to detect the antiplatelet effect of aspirin in the full aspirin effect group. Furthermore, no difference in the measurement values between the recovered aspirin effect and control group was found, irrespective of the assay performed. Measurement values in the variable aspirin effect group were different from those of the control group in the ASPItest using multiple electrode aggregometry and COL-EPI using PFA-100 but not in BT. ROC analysis showed the highest diagnostic accuracy in excluding the residual aspirin effect in the ASPItest (AUC 0.81, P < 0.001), followed by COL-EPI (AUC 0.78, P < 0.001) and BT (AUC 0.56, P = 0.05). The cutoff value of 53 U in the ASPItest excluded the effect of aspirin with a sensitivity of 88% and specificity of 71%. CONCLUSIONS: The full therapeutic antiplatelet effects of aspirin can be expected within 48 hours of the patient's last aspirin ingestion. Platelet function recovered in our study if aspirin cessation occurred >96 hours (4 days) before; thus, in these patients, preoperative platelet function testing is not useful. To quantify any residual aspirin effect in patients who ceased their intake of aspirin between 48 and 96 hours before surgery, the ASPItest might have the highest diagnostic accuracy.

Inhibitory effects of Bulnesia sarmienti aqueous extract on agonist-induced platelet activation and thrombus formation involves mitogen-activated protein kinases.

ETHNOPHARMACOLOGICAL RELEVANCE: B. sarmienti has long been recognized in folk medicine as a medicinal plant with various medicinal uses. Traditionally, it has been appreciated for the skin-healing properties of its essence. The bark has also been employed to treat stomach and cardiovascular disorders and reported to have antitumor, antioxidant and anti-inflammatory activities. However, information on its antiplatelet activity is limited. AIM OF THE STUDY: To examined the effects of B. sarmienti aqueous extract (BSAE) in platelet physiology. MATERIALS AND METHODS: The anti-platelet activity of BSAE was studied using rat platelets for in vitro determination of the extract effect on agonist-induced platelet aggregation, ATP secretion, [Ca(2+)](i) mobilization and MAP kinase phosphorylation. The extract in vivo effects was also examined in arterio-venous shunt thrombus formation in rats, and tail bleeding time in mice. RESULT: HPLC chromatographic analysis revealed that B. sarmienti extract contained (+)-catechin (C), (-)-epigallocatechin (EGC), (-)-epicatechin (EC), and (-)-epicatechin gallate (ECG). BSAE, significantly and dose dependently, inhibited collagen, thrombin, or ADP-induced platelet aggregation. The 50 percent inhibitory concentrations (IC(50)) of the extract for collagen, thrombin and ADP-induced platelet aggregation were 45.3+/-2.6, 100+/-5.6 and 110+/-4.6 microg/ml, respectively. Collagen activated ATP release and thrombin-induced intracellular Ca(2+) concentration were reduced in BSAE-treated platelets. In addition, the extract in vivo activity showed that BSAE at 100 mg/kg significantly attenuated thrombus formation in rat extracorporeal shunt model while mice tail bleeding time was not affected. Moreover, BSAE attenuated p38 mitogen-activated protein kinase (p38 MAPK), c-Jun N-terminal kinase 1 (JNK1) and extracellular-signal-regulated protein kinase 2 (ERK2) phosphorylations. CONCLUSION: BSAE inhibits platelet activation, granule secretion, aggregation, and thrombus formation without affecting bleeding time, and that this effect is mediated by inhibition of P38, JNK1 and ERK2 phosphorylations. The ability of BSAE to inhibit platelet function might be relevant in cases involving aberrant platelet activation where the plant extract could be considered as a candidate to anti-platelet and antithrombotic agent.

Coagulopatías graves: diagnóstico clínico y analítico / Serious coagulation disorders: clinical and analytic diagnosis

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