Thrombophilic states in late gestosis

In 80 pregnant women with pre-eclampsia and in 38 healthy pregnant women malondialdehyde production by blood platelets, platelet survival and several haemostatic variables were determined. It was demonstrated that due to the enhanced platelet turnover pre-eclampsia was invariably accompanied by a thrombophilic state which in severe cases developed into chronic consumption coagulopathy.     

Flow cytometric and radioisotopic determinations of platelet survival time in normal cats and feline leukemia virus-infected cats

This study demonstrates the potential usefulness of a flow cytometric technique to measure platelet survival time in cats utilizing autologous platelets labeled in vitro with fluorescein isothiocyanate (FITC). When compared with a 51Cr method, no significant differences in estimated survival times were found. Both the 51Cr and FITC-labeling procedures induced similar changes in platelet shape and collagen-induced aggregation. Platelets labeled with FITC had significantly greater volumes compared with those of glutaraldehyde-fixed platelets. These changes were primarily related to the platelet centrifugation and washing procedures rather than the labels themselves. This novel technique potentially has wide applicability to cell circulation time studies as flow cytometry equipment becomes more readily available. Problems with the technique are discussed. In a preliminary study of the platelet survival time in feline leukemia virus (FeLV)-infected cats, two of three cats had significantly reduced survival times using both flow cytometric and radioisotopic methods. These data suggest increased platelet turnover in FeLV-infected cats.     

Inhibition of ADP-induced platelet aggregation by reduced factor Xa

Treatment of blood coagulation factor Xa with insolubilized hexyl-agarose derivative of prostaglandin E1 (PGE1) results in the generation of two sulfhydryl groups in the protein molecule. The reduced factor Xa was found to be a potent inhibitor of platelet aggregation and thromboxane A2 synthesis induced by ADP. In contrast to the inhibition of thromboxane formation, the reduced factor Xa had no effect on the formation of PGE2 indicating that thromboxane synthetase might be selectively inhibited by the reduced factor Xa. Incubation with oxidized glutathione reversed the inhibitory activity of factor Xa previously exposed to the insolubilized hormone. Soluble PGE1 also reduces factor Xa, but more slowly than the insolubilized PGE1. PGE1 also exhibits reducing ability as tested with redox dyes. Reduction of factor Xa by dithiothreitol also transformed the coagulation factor into an inhibitor of platelet aggregation and thromboxane A2 formation. These experiments indicate that reduction of factor Xa leads to a reversible alteration of the molecule which inhibits platelet aggregation induced by ADP. This effect of reduced factor Xa is probably mediated through the inhibition of thromboxane A2 synthesis.     

Surface plasmon resonance detection of blood coagulation and platelet adhesion under venous and arterial shear conditions

A surface plasmon resonance (SPR) based flow chamber device was designed for real time detection of blood coagulation and platelet adhesion in platelet rich plasma (PRP) and whole blood. The system allowed the detection of surface interactions throughout the 6mm length of the flow chamber. After deposition of thromboplastin onto a section of the sensor surface near the inlet of the flow chamber, coagulation was detected downstream of this position corresponding to a SPR signal of 7 to 8 mRIU (7 to 8 ng/mm2). A nonmodified control surface induced coagulation 3.5 times slower. Platelet adhesion to gold and fibrinogen coated surfaces in the magnitude of 1.25 and 1.66 mRIU was also shown with platelets in buffer, respectively. SPR responses obtained with PRP and whole blood on surfaces that were methylated or coated with von Willebrand factor (vWF), fibrinogen, or collagen, coincided well with platelet adhesion as observed with fluorescence microscopy in parallel experiments. The present SPR detection equipped flow chamber system is a promising tool for studies on coagulation events and blood cell adhesion under physiological flow conditions, and allows monitoring of short-range surface processes in whole blood.     

血小板反应性增高患者相关指标的检测与分析

目的:探讨反应性血小板增高患者凝血指标及血小板聚集功能指标变化规律。方法:143例血小板反应性增高患者和65例对照者同时检测血小板聚集功能、抗凝血酶活性(AT-Ⅲ)、凝血酶原时间(PT)和活化部分凝血活酶时间(APTT),并统计分析。结果:血小板反应性增高常见于肿瘤、肺炎、外伤患者;血小板反应性增高组患者AT-Ⅲ、PT和APTT与对照组无差异,但患者血小板聚集功能显著高于对照组。结论:血小板反应性增高患者血小板聚集功能增强,建议定期监测血小板聚集功能,必要时用抗血小板聚集药预防。     

Mechanisms of Thrombocytopenia in Malignant Tertian Malaria

The mechanism of thrombocytopenia in six patients with falciparum malaria has been studied. All the patients recovered after antimalarial therapy, and cerebral malaria was not a feature. Radioactive-labelled platelets and fibrinogen were injected into the patients during the phase of thrombocytopenia. In all cases recovery of injected platelets was notably subnormal, indicating excessive splenic pooling of platelets. Platelet life span was moderately shortened in all patients, and platelet turnover increased approximately two-fold. Fibrinogen catabolism was moderately increased in all patients, but coagulation tests failed to reveal evidence of disseminated intravascular coagulation. The results suggest that in uncomplicated cases of malaria thrombocytopenia is the result of splenic pooling of platelets aggravated by a moderate decrease in platelet life span. In such cases thrombocytopenia is thus not the result of disseminated intravascular coagulation (D.I.C.), and heparin therapy is not indicated unless there is unequivocal ancillary evidence of D.I.C.     

不同化疗方案对非小细胞肺癌患者凝血纤溶功能及血小板参数的影响及其临床意义

目的:探讨不同化疗方案对非小细胞肺癌患者凝血纤溶功能及血小板参数的影响及临床意义。方法:回顾性分析2013年2月至2016年2月于我院进行治疗的96非小细胞肺癌患者的临床资料,按照化疗方案的不同分为TP组(50例)及GP组(46例),TP组患者给予多西他赛联合卡铂方案(TP方案)进行化疗,GP组患者给予吉西他滨联合卡铂方案(GP方案)进行化疗,另选择45例健康体检者作为对照组。比较三组治疗前者血浆凝血酶原时间(PT)、活化部分凝血活酶时间(APTT)、血浆凝血酶时间(TT)、血浆纤维蛋白原含量(FIB)以及D-二聚体(D-dimer)、血小板数(PLT)、血小板比积(PCT)、血小板平均体积(MPV)、血小板体积分布宽度(PDW)以及大体积血小板比率(P-LCR)及TP组和GP组治疗后以上指标的差异。结果:TP组和GP组患者化疗前PT、APTT、TT、FIB、D-dimer、PLT、PCT、MPV、PDW以及P-LCR水平均明显高于对照组(P0.05),而TP组与GP组以上指标比较无显著差异(P0.05)。治疗后,TP组和GP组患者PT、APTT、TT、FIB、D-dimer、PLT、PCT、MPV、PDW以及P-LCR水平均较治疗前有所下降,且GP组TT明显长于TP组(P0.05),PLT、PCT明显低于TP组(P0.05)。结论:凝血纤溶功能及血小板参数对于评价不同化疗方案治疗非小细胞肺癌患者预后具有积极的临床价值,不同化疗方案选择对于患者凝血系统均具有一定的影响。     

Simulated VLF-fields as a risk factor of thrombosis

VLF (Very Low Frequencies)-fields are damped electromagnetic waves of atmospheric origin (sferics). Sferics were artificially produced within a steel-built chamber; blood was drawn and platelet adhesiveness, platelet cyclic AMP and coagulation factors were measured in human volunteers placed within the chamber. Following frequency of the impulses of 10 Hz and a field strength of 400 mV/m increased platelet adhesiveness and decreased platelet cyclic AMP. Medication of the anti-platelet drugs were not effective at all, but the pretreatment of dipyridamole 75 mg combined with acetylsalicylic acid 100 mg blocked the sferics induced increment in platelet adhesiveness. Psychologically labile volunteers exhibited more marked effects of sferics upon platelet adhesiveness. Simulation of stressors upon platelets showed the same effect. The increase in platelet adhesiveness induced by all kind of stressors is not a risk factor of thrombosis in itself. Only if the vessel walls are damaged, e.g. by atherosclerotic plaques, or if the blood flow is reduced, e.g. by heart failure, then the increased platelet adhesiveness will cause thrombosis.Supported by Deutsche Forschungsgemeinschaft and Landesamt für Forschung NRW.     

Norepinephrine, but not epinephrine, enhances platelet reactivity and coagulation after exercise in humans

The effects of exercise and catecholamineson platelet reactivity or coagulation and fibrinolysis appear to beinconsistent. This may be partly due to the methods employed inprevious studies. In the present study, we investigated the effects ofacute aerobic exercise and catecholamines on the thrombotic status by anovel in vitro method, shear-induced hemostatic plug formation(hemostatometry), using nonanticoagulated (native) blood. Aerobicexercise (60% maximal O₂consumption) was performed by healthy male volunteers for 20 min, andthe effect on platelet reactivity and coagulation was assessed byperforming hemostatometry before and immediately after exercise.Exercise significantly increased shear-induced platelet reactivity,coagulation, and catecholamine levels. The effect of catecholamines onplatelet reactivity and coagulation was assessed in vitro by addingcatecholamines to blood collected in the resting state. The mainfindings of the present study are that elevation of circulatingnorepinephrine at levels that are attained during exercise causesplatelet hyperreactivity and a platelet-mediated enhanced coagulation.This may be a mechanism of an association of aerobic exercise withthrombotic risk.

     

Effect of ethyl alcohol on selected parameters of the hemostasis system in vitro]

Alcohol produces several disorders in all components of hemostasis system. However, its mechanism of action is not clear. Therefore, an effect of ethyl alcohol on the selected parameters of both platelet and plasma hemostasis has been examined in vitro. Blood aggregation induced by ADP and PAF and platelet-leucocytic aggregates have been determined in vitro in the group of 45 healthy volunteers. Out of plasma parameters the selected factors of blood coagulation and fibrinolysis have been examined. Results suggest that the examined concentrations of ethyl alcohol mainly affect platelet function decreasing platelet aggregation. Alcohol does not affect significantly blood coagulation and fibrinolysis occurring in vitro.     

Importance of Initial Concentration of Factor VIII in a Mechanistic Model of In Vitro Coagulation

This computational study generates a hypothesis for the coagulation protein whose initial concentration greatly influences the course of coagulation. Many clinical malignancies of blood coagulation arise due to abnormal initial concentrations of coagulation factors. Sensitivity analysis of mechanistic models of blood coagulation is a convenient method to assess the effect of such abnormalities. Accordingly, the study presents sensitivity analysis, with respect to initial concentrations, of a recently developed mechanistic model of blood coagulation. Both the model and parameters to which model sensitivity is being analyzed provide newer insights into blood coagulation: the model incorporates distinct equations for plasma-phase and platelet membrane-bound species, and sensitivity to initial concentrations is a new dimension in sensitivity analysis. The results show that model predictions are most uncertain with respect to changes in initial concentration of factor VIII, and this hypothesis is supported by results from other models developed independently.     

Coagulation and fibrinolysis in intact hydatidiform molar pregnancy.

Tests of coagulation, fibrinolysis, and platelet function were performed in 17 patients with intact molar pregnancies. Women with intact molar pregnancies had higher fibrinogen factor VIII, and fibrinogen degradation products, concentrations and lower prothrombin, factor X, plasminogen, and plasminogen activator concentrations than controls with normal pregnancies. They also had reduced platelet counts and thromboelastographic values, which indicated hypocoagulability. These results suggest that intravascular coagulation occurs in intact hydatidiform molar pregnancies.     

Inhibition of platelet aggregation by S-(1,2-dicarboxyethyl)glutathione, intrinsic tripeptide in liver, heart, and lens

S-(1,2-Dicarboxyethyl)glutathione (DCE-GS) found in animal tissues or baker's yeast showed strong inhibitory effects on blood coagulation and platelet aggregation. The inhibitory effect of blood coagulation was almost the same as those of EDTA, oxalate, and citrate. DCE-GS did not show chelating activity. As for ADP- or thrombin-induced platelet aggregations, DCE-GS exerted a potent effect on the secondary aggregation, while it was less active in the primary aggregation. DCE-GS gave a distinct lag period in the time course of the secondary aggregation induced by collagen and inhibited most strongly the aggregation induced by arachidonic acid compared with those elicited by ADP, thrombin, and collagen. The peptide, however, did not inhibit the platelet aggregation induced by 12-O-tetradecanoylphorbol-13-acetate. Although both DCE-GS and EDTA inhibited the platelet aggregation which was triggered by ADP, their inhibitory manners were entirely different.     

急、慢性缺氧对大鼠凝血机能的影响

本文讨论了实验性缺氧对大鼠凝血机能产生的影响。实验结果表明,大鼠在模拟8000米高度两小时后,血小板凝聚性、血小板因子3活性明显增加,纤溶活性下降,同时,纤维蛋白原含量和因子X也明显下降。大鼠在模拟7000米经36天间歇性慢性缺氧,血小板计数、血小板凝聚性,血小板因子3活性、纤维蛋白原含量、因子X活性均显著增加,部分凝血活酶时间缩短、纤溶活性下降,明显地出现凝血增强的趋势。本文还讨论了抗缺氧药物复方党参、异叶青兰对人鼠急性缺氧时凝血机能的影响。     

Influence of cysteine proteinase inhibitors on platelet and plasma components of blood coagulation system

Factor XIIIa plays an important role in stabilization of formed fibrin clot during blood coagulation. Recent studies proved that factor XIIIa affects formation of coated platelets, which are highly procoagulant and characterized by a high level of alpha-granular proteins on their surface and expose surface phosphatidylserine after platelet activation. The ability of newly found cysteine proteinase inhibitors (CPIs) from plants to affect thiol group of the factor XIIIa active centre was recently discovered. Here, the effect of CPIs on the formation of coated platelets and activity of plasma components during blood coagulation process was investigated. It was found that CPIs dose-dependently decreased the fraction of coated platelets in the total platelet population during platelet activation and decreased endogenous thrombin potential (ETP) by 40% for thrombin generation in platelet-rich as well as in platelet-poor plasma. Such decrease of ETP could not be explained by the CPIs influence on factor XIIIa. Investigation of the effects of these inhibitors on factor Xa and thrombin activity has shown that CPIs dose-dependently inhibited their activity and might cause an ETP decrease. Thus, the obtained data indicated that CPIs affected both platelet and plasma components of blood coagulation system.     

Effects of Extremely Low Frequency Magnetic Fields on Blood Coagulation in Mice: An Initial Study

OF1 mice were chronically exposed to a 50‐Hz sinusoidal East–West magnetic field 15 µT (rms), in order to evaluate the blood coagulation variations related to the effect of this nonionizing radiation. Mating and pregnancy of ancestors (first generation), and birth, lactation, and development of second‐generation female mice until adulthood took place in the experimental field. A global blood coagulation study of both control and exposed 14‐ to 15‐week‐old and 50‐ to 52‐week‐old, second‐generation females was carried out. Plasma calcium content was determined by atomic absorption spectrophotometry. Different steps of blood coagulation were studied by thromboelastography (TEG) in whole blood (WB), platelet‐rich plasma (PRP), and platelet‐poor plasma (PPP). A significant decrease (approximately 34.5%) of calcium concentration was detected with aging; however, no change was induced by medium‐term or long‐term exposure to extremely low frequency magnetic field (ELF‐MF). Medium‐term exposure could not be related to noticeable changes in global coagulation. However, a great deterioration of fibrin clot formation in mature exposed female mice was detected as a result of the long‐term exposure that was strengthened by aging. These deficiencies seemed to be compensated by the discrete, although statistically not significant, decrease of platelet counts and the significant decrease of blood cells' mean corpuscular volume associated to ELF‐MF exposure of 50‐Hz, 15 µT. Consequently, whole blood TEG values of mature exposed female mice were similar to those from the young control group. In view of the obtained results, further studies on variations associated with ELF‐MF exposure in different coagulation parameters will be necessary.     

An ethanol extract of Ramulus mori improves blood circulation by inhibiting platelet aggregation

Inappropriate platelet aggregation can cause blood coagulation and thrombosis. In this study, the effect of an ethanol extract of Ramulus mori (ERM) on blood circulation was investigated. The antithrombotic activity of ERM on rat carotid arterial thrombosis was evaluated in vivo, and the effect of ERM on platelet aggregation and blood coagulation time was evaluated ex vivo. To evaluate the safety of ERM, its cytotoxicity to platelets and its effect on tail bleeding time were assessed; ERM was not toxic to rat platelets and did not prolong bleeding time. Moreover, administering ERM to rats had a significant preventive effect on carotid arterial thrombosis in vivo, and significantly inhibited adenosine diphosphate- and collagen-induced platelet aggregation ex vivo, whereas it did not prolong coagulation periods, such as prothrombin time and activated partial thromboplastin time. The results suggest that ERM is effective in improving blood circulation via antiplatelet activity rather than anticoagulation activity.     

Blood Coagulation and Platelet Economy in Subjects with Primary Gout

Previous studies have suggested that there is an increased incidence of degenerative vascular disease in patients with gout and an increased rate of turnover of blood platelets in patients and animals with atherosclerosis. A disturbed uric acid metabolism and “secondary” gout have long been known to occur with bone marrow diseases. A study of platelet economy and blood clotting factors in subjects with primary gout was therefore undertaken.Twenty-two male subjects with gout but with no clinical evidence of vascular disease were studied. Half of these had a negative family history for vascular disease and half had less fortunate ancestors. The most striking differences were found when gouty patients with a negative family history for vascular disease were compared with similar control subjects. The mean platelet half-life was 2.85 days in the gouty subjects and 3.74 days in the controls. The mean platelet turnover (number/c.mm./day) was 58,750 in gouty subjects, 42,370 in controls. Platelet adhesiveness and plasma thromboplastic activity were correspondingly increased in the gouty subjects. Control subjects with a positive family history all showed relatively active clotting system and platelet turnover, similar to the values found in atherosclerotic subjects. The data indicated that there is increased platelet destruction and production in some patients with primary gout. The relation between this anomaly and the vascular disease, and disturbed urate metabolism in gouty subjects, remains to be investigated.     

Anticoagulant activity of M-LAO,L-amino acid oxidase purified from Agkistrodon halys blomhoffii,through selective inhibition of factor IX

One of haemorrhagic toxins present in snake venoms is L-amino acid oxidase (LAO), which catalyzes the oxidative deamination of L-amino acids with the generation of hydrogen peroxide. Although it is widely accepted that LAO alters platelet function, the effects of LAO on human blood coagulation remain largely unknown. The present study demonstrated, for the first time, that M-LAO, LAO purified from the venom of Agkistrodon halys blomhoffii (Japanese mamushi), possesses an anticoagulant activity. Thrombelastography (TEG) showed that M-LAO significantly delayed the onset and the progress of the coagulation process. In addition, the enzyme prolonged the activated partial thromboplastin time (aPTT) dose-dependently, but had little effect on the prothrombin time (PT), suggesting that its principal activity was mediated in the intrinsic coagulation pathway. Furthermore, M-LAO reduced factor IX procoagulant activity in a dose-dependent manner and did not affect other coagulation factors. These results indicate that M-LAO has an anticoagulant activity that impairs the intrinsic clotting by inhibiting factor IX.     

Inositol phospholipid turnover in platelets of schizophrenic patients.

Abnormalities in blood cell membrane phospholipid composition and metabolism from schizophrenic patients have been reported by many groups of investigators. Among membrane phospholipids, inositol phospholipids are of special importance as they are involved in transduction system that generates second messengers such as inositol trisphosphate and diacylglycerol. Our studies on platelet inositol phospholipid turnover suggest a significant increase in platelet phosphatidylinositol 4,5-bisphosphate levels, an increased production of inositol trisphosphate in neuroleptic-treated and neuroleptic-free schizophrenic patients platelets and a reduced calcium release by thrombin in neuroleptic-treated schizophrenic patients platelets. The enhanced production of inositol trisphosphate may be due to an increase in its precursor phosphatidylinositol 4,5-bisphosphate with an associated desensitisation of the intracellular inositol trisphosphate receptor by neuroleptics, which may explain the diminished calcium response to thrombin in schizophrenic patients platelets.