Effects of Berbamine on PAF Production in Human Neutrophils and on Platelet Aggregation

The effects of berbamine, an alkaloid of dibenzylisoquinoline, on PAF produc tion in human neutrophils and on platelet aggregation induced by PAF were studied and compared with those of the calcium antagonist verapamil. Preincubation with berbamine (50 mmol / L, 100 mmol / L) or verapamil (10 mmol / L, 100 mmol / L) was shown to significantly inhibit A 23187 stimulated PAF synthesis. Berbamine and verapamil were found to inhibit platelet aggregation induced by PAF 70 pmol / L in a dose dependent manner. These results suggest that the inhibitory effects of berbamine and verapamil on A 23187 stimulated PAF synthesis in human neutrophils and PAF induced platelet aggregation are possibly brought about by inhibiting cellular calcium influx.

Inhibitory Effect of β-Elemene Emulsion on Platelet Aggregation and its Mechanism

为阐明β榄香烯的抗血小板作用，本文分别采用比浊法和放免法测定大鼠连续ｉｐ７ｄβ榄香烯乳６．２５～１２．５ｍｇ·ｋｇ－１·ｄ－１后对血小板聚集、血浆ｋｅｔｏＰＧＦ１α和ＴＸＢ２水平的影响。结果表明，本品分别使凝血酶、花生四烯酸和ＡＤＰ诱导血小板最大聚集率下降３８．３％～４２．６％，１４．７％～１９．１％和７．２％～１０．８％，血浆ＴＸＢ２从８８ｎｇ·Ｌ－１下降至７２ｎｇ·Ｌ－１，ｋｅｔｏＰＧＦ１α从１７．５ｎｇ·Ｌ－１增加至２０．９ｎｇ·Ｌ－１。提示ＴＸＢ２降低和ｋｅｔｏＰＧＦ１α值增加是其抑制血小板聚集的作用机制之一。

Studies on the Basic Principles for the Processing of Rhizoma Cibotii Part Ⅰ Influence of Rhizoma Cibotii and Its Processed Samples on Thrombin Induced Rabbit Platelet Aggregation

比较研究了狗脊及其不同炮制品对凝血酶诱导的兔血小板聚集作用的影响 ,各炮制品均有抑制血小板聚集作用 ,抗血小板聚集作用砂烫品 >盐制品 >酒蒸品 >单蒸品 >

EFFECTS OF NIMODIPINE ON PLATELET AGGREGATION AND THE ACTIVITY OF ENZYMES IN ARACHIDONIC ACID METABOLISM

The effects of nimodipine on platelet aggregation and arachidonic acid(AA)metabolism were studied in order to explore its effect on patients with thrombosis or cardiovas- cular disease.The results indicate that nimodipine(50-350μmol/L)significantly inhibits platelet aggregation induced by ADP,AA,and ionophore A23187 in a dose dependent manner.The inhibitory effects induced by ionophore A23187 could be partially antagonized by calcium(1 mmol/L).When the substrate was AA and the enzyme was supplied by pig lung microsomes,nimodipine(50-400μmol/L)significantly reduced the generation of TXB_2 and 6-keto-PGF_(1a) in parallel.When the substrate was prostaglandin endoperoxide, however,the levels of TXB_2 and 6-keto-PGF_(1a)were not significantly altered in the same concentration range.The results suggest that nimodipine is a cyclooxygenase inhibitor,and its ability to inhibit platelet aggregation is related to its calcium blocking effect.

Plasma pharmacological study on Da Huang Zhe Chong capsule on platelet aggregation of normal person

Objective To develop a plasma pharmacological method evaluates the effect of Da Huang Zhe Chong capsule on platelet aggregation and its mechanism, which is a representative Traditional Chinese Medicine Patent Prescription Promoting blood circulation by removing blood stasis. Methods Platelets specimens from healthy volunteers made serum and plasma with medicine, while platelet PRP were separated, which were divided into 8groups,i.e. auto-serum, allo-serum, serum with Da Huang Zhe Chong capsule , serum with aspirin, auto-plasma, plasma with Da Huang Zhe Chong capsule, plasma with aspirin, every group added to serum and plasma to hatch. After ADP and adrenalin were added into the specimens and hatched, the effects of specimens on platelet aggregation were observed. Results After ADP adrenalin were added, all the serum groups did not present platelet aggregation,while all the plasma group presented platelet aggregation. P1, P5, Pmax, t and TM have no significant difference (P＞0. 05) between auto-plasma group and allo-plasma group induced by ADP and adrenalin. P1, P5, t and Pmax have significant differences (P＜0. 01) and TM decreased significantly (P＜0. 05) comparing plasma group with Da Huang Zhe Chong capsule and plasma group of aspirin to allo-plasma group. P1, t and Pmax have significant difference (P＜0.05), and P5 and TM are simulate comparing plasma group with Da Huang Zhe Chong capsule to plasma group of aspirin. P1, P5, t and Pmax have significant differences (P＜0. 01), P1, TM have also significant(P＜0. 05), comparing plasma group of Da Huang Zhe Chong capsule with plasma of aspirin to allo-plasma group induced by adrenalin. P1 ,P5 and Pmax have significant differences (P＜0.05), and t and Pmax are simulate comparing plasma group with Da Huang Zhe Chong capsule with plasma group of aspirin. Conclusion The serum pharmacological study is inappropriate to study platelet aggregation in vitro. The plasma pharmacological study is inappropriate to study platelet aggregation in vitro. The plasma pharmacological study could reflect the pharmacological effect produced in vivo. Da Huang Zhe Chong capsule has better anti artery thrombosis effect than aspirin, and it is an ideal medicine for anti artery thrombosis.

Components of traditional Chinese medicine inhibit platelet aggregation by blocking ADP receptor subtypes P2Y1 and P2Y12

Platelets aggregation and thrombosis formation are major reasons of cardiovascular and cerebral vascular diseases.To develop new generative,potent and safe agents for inhibiting platelet aggregation and preventing above diseases are urgently required.Some traditional Chinese medicines of″Houxue Huayu″have been shown to inhibit platelet aggregation potently.In the present study the mechanisms and the molecular targets of puerarin,salvianolic acid B and the analogue of 3-n-butylphthalide,dl-PHPB were investigated and compared with ticlopidine.Four platelet aggregation inducers,ADP,arachidonic acid,collagen and thrombin were used in the study.It was found that puerarin and dl-PHPB specifically inhibited ADP induced platelet aggregation like ticlopidine did.However,salvianolic acid B inhibited both ADP and collagen induced platelet aggregations with similar potency.Due to existing two ADP receptor subtypes on platelets,P2Y1 and P2Y12,we studied the action of above compounds on the receptors and the signaling pathways.It was found that dl-PHPB decreased IP1 accumulation produced by ADP,but had no effect on IP1 level induced by m-3M3 FBS,an activator of PLC.M-3M3 FBS might attenuate the inhibitory effect of dl-PHPB on ADP-induced platelet aggregation.In addition,dl-PHPB did not affect cyclic AMP formation in platelets by ADP,which is different from P2Y12 antagonist ticlopidine.Puerarin showed the similar effects of dl-PHPB.Therefore,the actions of dl-PHPB and puerarin might be through P2Y1receptor-PLC-βpathway.Salvianolic acid B did not reduce the IP1 accumulation stimulated by ADP.It might act on the receptor subtype P2Y12.Our results suggest that components of Chinese herb medicine might be a resource for development of novel anti-platelet drugs.

Synthesis of Novel Ligustrazine Derivatives as Potential Platelet Aggregation Inhibitors

A series of novel ligustrazine derivatives were synthesized. These compounds have not been reported in literature, and their chemical structures were confirmed by IR, ^1H NMR and ESI-MS. The preliminary antiplatelet aggregation screening results demonstrated that the compounds 7a, 7b and 7c showed higher potency than ligustrazine.

A practical synthesis of sarpogrelate hydrochloride and in vitro platelet aggregation inhibitory activities of its analogues

A convenient approach for the preparation of sarpogrelate hydrochloride was developed.Two series of sarpogrelate hydrochloride analogues were designed and synthesized in order to improve their platelet aggregation inhibitory activities, biological tests suggested that these compounds have platelet aggregation inhibitory activities to some extent.

The increase of adenylate kinase activity in the blood can control aggregation of platelets in coronary or peripheral arterial ischemia

Activation and aggregation of blood platelets is crucial for hemostasis and thrombosis. In the vascular system adenine nucleotides are important signaling molecules playing a key role in hemostasis. ADP was the first low molecular weight agent recognized to cause blood platelets activation and aggregation. NTPDases and adenylate kinase (AK) are the main enzymes involved in metabolism of extracellular adenine nucleotides. The majority of studies concentrated on the role of NTPDase1 (apyrase) in the inhibition of platelets aggregation. Up to now, there are still insufficient data concerning the role of AK in this process. We found that adenylate kinase activity in the serum of patients with myocardial infarction is significantly increased when compared to the healthy volunteers. The elevated activity of AK is connected to appearance of another isoform of that enzyme, expressed in patients with myocardial infarction. The influence of AK on the pig blood platelets aggregation induced by 20 μM ADP or 7.5 μg/ml rat collagen was examined. 1U of adenylate kinase added to platelet-rich plasma (PRP) before ADP or collagen, inhibited the platelets aggregation. One minute after induction of platelets activation by ADP as much as 5U of adenylate kinase was necessary to stop the platelet aggregation. In the case of collagen activated aggregation, only 2U of AK added 1 or 5 minutes after initiation of the aggregation process were sufficient for disaggregation of platelets. The increase of ATP: ADP ratio is probably responsible for the initiation of disaggregation process. We conclude that adenylate kinase is involved in regulation of plate-lets aggregation. Anticoagulative role of AK indicates the possibility of using this enzyme in the treatment of cardiovascular diseases.

Time-effect and dose-effect of prasugrel hydrobromide acetic acid compound inhibiting platelet aggregation

Aim To evaluate the time-effect and dose-effect of prasugrel hydrobromide acetic acid compound （PHAAC） inhibiting platelet aggregation. Methods For the time-effect study, 190 Sprague-Dawley （SD） rats were devided into 19 groups （n- 10）： the vehicle control group, the PHAAC groups （0.5, 1, 2, 4, 6, 24, 48, 72, 96 h） and the prasugrel hydrochloride groups （0.5, 1, 2, 4, 6, 24, 48, 72, 96 h）. Rats were singly intra- gastic administration of the vehicle, the PHAAC （5 mg·kg^-1） or the prasugrel hydrochloride （5 mg · kg^-1 ）, re- spectively. Blood samples were taken at each time point for the determination of platelet aggregation rate （PAR）. For the dose-effect study, 110 SD rats were devided into 11 groups （n= 10）： the vehicle control group, the PHAAC groups （10, 5, 2.5, 1, 0.5 mg · kg^-1, dosage of prasugrel） and the prasugrel hydrochloride groups （ 10, 5, 2.5, 1, 0.5 mg · kg^-1, dosage of prasugrel） . Blood samples were taken at 4 h after drug administration for the determination of PAR. Results Compared with the vehicle group, PHAAC has significant anti-platelet ag- gregative effects （P 〈 0.05） at the time of 0.5, 1, 2, 4, 6, 24, 48 h, and the effect at the time of 4 h was the strongest. There were no obvious differences between the effect of PHAAC （5 mg · kg^-1） and prasugrel hydrochlo- ride （5 mg · kg^-1） at each time point. Compared with the vehicle group, intragastic administration of PHAAC at the doses of 10, 5, 2.5, 1, 0.5 mg · kg^-1 could obviously inhibite the platelet aggregation, and showed a dose- dependent manner. There were no significant differences between the effect of PHAAC and prasugrel hydrochloride at the same dose. Conclusion PHAAC can inhibit platelet aggregation in a dose-dependent manner, and the effect at 4 h after drug administration is the strongest. The action strength and duration of PHAAC are similar with that of the prasugrel hydrochloride.

Effect of adjuvant therapy with ginkgo-damole on apoptosis, nerve injury and platelet aggregation of patients with acute cerebral infarction

Objective:To investigate the effect of adjuvant therapy with ginkgo-damole on apoptosis, nerve injury and platelet aggregation of patients with acute cerebral infarction. Methods:A total of 74 patients with acute cerebral infarction treated in our hospital from March 2014 to December 2015 were retrospectively analyzed, and they were divided into ginkgo-damole group and conventional treatment group according to a therapeutic schedule that whether ginkgo-diyidamolum were included. At Week 2 and Week 4 after treatment, contents of apoptosis molecule, nerve injury molecule and index of platelet aggregation in serum were detected. Results:At Week 2 after treatment, contents of soluble Fas, soluble Fas ligand, soluble tumor necrosis factor related apoptosis inducing ligand, S100β, neuron specific enolase, glial fibrillary acidic protein, myelin basic protein, malonaldehyde, endothelin-1, fibrinogen and D-dimer in patients' sera of ginkgo-damole group were significantly lower than those of conventional treatment group. Contents of nitric oxide in sera were obviously higher than that of conventional treatment group. At Week 4 after treatment, contents of soluble Fas, soluble Fas ligand, soluble tumor necrosis factor related apoptosis inducing ligand, S100β, neuron specific enolase, glial fibrillary acidic protein, myelin basic protein, malonaldehyde, endothelin-1, fibrinogen and D-dimer in patients' sera of ginkgo-damole group were significantly lower than those of conventional treatment group. Contents of nitric oxide in sera were obviously higher than that of conventional treatment group. Conclusions:Adjuvant therapy with ginkgo-damole can inhibit the apoptosis of neuron cells and neurogliocyte and reduce the neural function injury and the situation of platelet aggregation.

Evaluation of the Effect of Aspirin on Platelet Aggregation: Methodological Recommendations for Aspirin-Drug Interaction Studies

Given the broad application of aspirin as antiplatelet drug, availability of standardized methodology to assess potential interaction with any co-medication on platelet aggregation is desired. We characterized the effect of aspirin (ASA) therapy on collagen-induced platelet aggregation in whole blood to define such methodology. Collagen-induced platelet whole blood aggregation was assessed in 6 healthy male volunteers on 2 occasions (Day 1, Day 7) using the Chronolog aggregometer. From Day 2 up to Day 7, subjects received a daily oral dose of 75 mg ASA. The relationship between collagen dose and platelet aggregation response was assessed. On Day 1, maximal aggregation was observed at 1 μg/mL collagen (15.3 ± 4.6 Ω) and higher. Reproducible results were obtained without any indication of intra-subject fluctuations. ASA treatment decreased maximal aggregation by 80% and 38% at 0.5 and 2.0 μg/mL collagen, respectively. Power calculations were performed based on the observed intra-subject variability and demonstrated minimal sample sizes of 9 - 11 subjects for future cross-over ASA-drug interaction studies exploring effects on platelet aggregation, which demonstrates that the proposed collagen-induced ex vivo whole blood platelet aggregation is a feasible methodology to evaluate ASA-drug interactions in healthy volunteers.

Inhibitory effects and mechanisms of high molecular-weight phlorotannins from Sargassum thunbergii on ADP-induced platelet aggregation

We evaluated the effects of high molecular-weight phlorotannins from Sargassum thunbergii(STP) on ADP-induced platelet aggregation and arachidonic acid(AA) metabolism in New Zealand white rabbits and Wistar rats.The inhibition of STP on platelet aggregation was investigated using a turbidimetric method,and the levels of the terminal products of AA metabolism were measured using the corresponding kits for maleic dialdehyde(MDA),thromboxane B2(TXB2) and 6-keto-prostaglandin F1α(6-keto-PGF1α) by colorimetry and radioimmunoassay,as appropriate.We found that STP could inhibit ADP-induced platelet aggregation,and the inhibitory ratio was 91.50% at the STP concentration of 4.0 mg/mL.Furthermore,STP markedly affected AA metabolism by decreasing the synthesis of MDA(P<0.01) and increasing the synthesis of 6-keto-PGF1α,thus changing the plasma TXB2/6-keto-PGF1α balance when the platelets were activated(P<0.01).Therefore,STP altered AA metabolism and these findings partly revealed the molecular mechanism by which STP inhibits ADP-induced platelet aggregation.

Study on the targets and mechanisms of traditional Chinese medicine in inhibiting platelet aggregation

Platelets aggregation and thrombosis formation are major reasons of cardiovascular and cerebral vascular diseases.To develop novel,effective and safe agents for inhibiting platelet aggregation and preventing above diseases is urgently needed.Some traditional Chinese medicines for“Houxue Huayu”have been shown to inhibit platelet aggregation potently.They are used frequently in China and also in Asian countries.Recently,the major effective components of Pueraria lobata,Salvia miltiorrhiza Bunge,Apium graveolens L.and so on were studied.The mechanisms and the molecular targets of puerarin,salvianolic acid B and the analogue of 3-n-butylphthalide,dl-PHPB were investigated.Four platelet aggregation inducers,ADP,arachidonic acid(AA),collagen(Col)and thrombin,were used in the study.

Platelets in hemostasis and thrombosis:Novel mechanisms of fibrinogen-independent platelet aggregation and fibronectin-mediated protein wave of hemostasis

Platelets are small anucleate cells generated from megakaryocytes in the bone marrow. Although platelet genera- tion, maturation, and clearance are still not fully understood, significant progress has been made in the last 1-2 dec- ades. In blood circulation, platelets can quickly adhere and aggregate at sites of vascular injury, forming the platelet plug （i.e. the first wave of hemostasis）. Activated platelets can also provide negatively charged phosphatidylserine- rich membrane surface that enhances cell-based thrombin generation, which facilitates blood coagulation （i.e. the second wave of hemostasis）. Platelets therefore play central roles in hemostasis. However, the same process of hemostasis may also cause thrombosis and vessel occlusion, which are the most common mechanisms leading to heart attack and stroke following ruptured atherosclerotic lesions. In this review, we will introduce the classical mechanisms and newly discovered pathways of platelets in hemostasis and thrombosis, including fibrinogen-inde- pendent platelet aggregation and thrombosis, and the plasma fibronectin-mediated ＂protein wave＂ of hemostasis that precedes the classical first wave of hemostasis. Furthermore, we briefly discuss the roles of platelets in inflam- marion and atherosclerosis and the potential strategies to control atherothrombosis.

Effects of procainamide on adenosine diphosphate-induced platelet aggregation and thromboxane B_2 production in rabbits in vitro

Turbidimetry and radioimmunoassay were used to study the effects of procainamide (PA ) onadenosine diphosphate (ADP)-induced rabbit platelet aggregation and thromboxane B2 (TXB2) production invitro. PA 8. 5--544. 0 μmol L-1 inhibited ADP-induced platelet aggregation and TXB2 production, and theinhibition rates were 26. 7% -- 66. 7 % and 21. 4 % -- 70. 1 %, respectively. There was positive correlation between PA concentration and its efficiency in inhibiting the platelet aggregation and TXB2 production, and alsobetween the inhibition rates of platelet aggregation and that of TXB2 production. The three linear equationsand main parameters were The results indicate that PA could significantly inhibit ADP--induced platelet aggregation and TXB2 production in rabbits.

Impacts of Aggregation Methods and Trophospecies Number on the Structure and Function of Marine Food Webs

Aggregation of species with similar ecological properties is one of the effective methods to simplify food web researches.However,species aggregation will affect not only the complexity of modeling process but also the accuracy of models’outputs.Selection of aggregation methods and the number of trophospecies are the keys to study the simplification of food web.In this study,three aggregation methods,including taxonomic aggregation(TA),structural equivalence aggregation(SEA),and self-organizing maps(SOM),were analyzed and compared with the linear inverse model–Markov Chain Monte Carlo(LIM-MCMC)model.Impacts of aggregation methods and trophospecies number on food webs were evaluated based on the robustness and unitless of ecological net-work indices.Results showed that aggregation method of SEA performed better than the other two methods in estimating food web structure and function indices.The effects of aggregation methods were driven by the differences in species aggregation principles,which will alter food web structure and function through the redistribution of energy flow.According to the results of mean absolute percentage error(MAPE)which can be applied to evaluate the accuracy of the model,we found that MAPE in food web indices will increase with the reducing trophospecies number,and MAPE in food web function indices were smaller and more stable than those in food web structure indices.Therefore,trade-off between simplifying food webs and reflecting the status of ecosystem should be con-sidered in food web studies.These findings highlight the importance of aggregation methods and trophospecies number in the analy-sis of food web simplification.This study provided a framework to explore the extent to which food web models are affected by dif-ferent species aggregation,and will provide scientific basis for the construction of food webs.

Meizothrombin Preparation and Its Role in Fibrin Formation and Platelet Aggregation

Meizothrombin (MT) is one of prothrombin derivatives which appears in haemostasis activation area. However, its role in haemostasis regulation isn’t clear. We studied the role of MT in fibrin formation, platelet activation and aggregation. A new effective method of obtaining MT from native human prothrombin was developed using immobilised prothrombin activator from Echis multisquamatis venom. The protein was stable and electrophoretically pure. Platelet-rich plasma for aggregation study and gel-sieved platelets for flow-cytometry were separated from blood of healthy donors. It was shown that MT transformed fibrinogen to fibrin and activated clotting factor XIII. MT didn’t activate gel-sieved intact platelets, but in platelet-rich plasma, increased platelet aggregation induced by ADP, collagen and adrenalin.

Effects of Procainamide on Human Blood Platelet Aggregation

We had demonstrated that procainamidc inhibitodarachonic aad, thnxnbin, donidine and caldum chlo-ride·itduoed platebet agtion inbits and guin-eathis study observed the e6ects of proc}inamideon Hood

A novel approach to Parkinson's disease treatment with a potentially dual-acting therapeutic agent that targetsα-synuclein aggregation and neuron death

Parkinson's disease(PD),a prevalent neurodegenerative disorder,is chara cterized by the loss of dopaminergic neurons and the aggregation ofα-synuclein protein into Lewy bodies.While the current standards of therapy have been successful in providing some symptom relief,they fail to address the underlying pathophysiology of PD and as a result,they have no effect on disease progression.