In an attempt to demonstrate the biological activities of a short peptide.Arg-Gly-Asp- Ser (RGDS) was synthesized and used for bioassay,The data obtained here proved that RGDS ob- viously inhibited PAF- and/or ADP-ind...In an attempt to demonstrate the biological activities of a short peptide.Arg-Gly-Asp- Ser (RGDS) was synthesized and used for bioassay,The data obtained here proved that RGDS ob- viously inhibited PAF- and/or ADP-induced platelet aggregation.The present paper revealed that RG- DS had vasodilative action and the cGMP accumulation may be one of the mechanisms of RGDS exer- ting bioactivities.展开更多
Effects of berberine (Ber) on platelet aggregation and TXB2 and 6 keto PGF1a plasma levels were studied in rabbits with uncomplete cerebral ischemia. Ber inhibited uncomplete cerebral ischemic rabbit platelet aggreg...Effects of berberine (Ber) on platelet aggregation and TXB2 and 6 keto PGF1a plasma levels were studied in rabbits with uncomplete cerebral ischemia. Ber inhibited uncomplete cerebral ischemic rabbit platelet aggregation triggered by collagen, ADP, and arachidonic acid (AA) with the IC 50 of 0.15, 0.46, and 0.51 mg·ml 1 , respectively. In rabbits, Ber 25, or 50 mg·kg 1 iv 30 min after uncomplete cerebral ischemia, restrained the collagen ADP and AA induced platelet aggregation determined 90 min later. With radioimmunoassay, we measured the thromboxane B2 (TXB 2) and 6 ketoprostaglandin F 1α (6 keto PGF 1α ) contents in rabbit plasma. The results indicated that the TXB 2 level in rabbit 120 min after uncomplete cerebral ischemia (921±539 pg·ml 1 ) was higher than that (230±71 pg·ml 1 ) in normal rabbits ( P < 0.01), but 6 keto PGF 1α level after ischemia (73±23pg·ml 1 ) was lower than that (262±988pg·ml 1 ) in normal rabbit. Ber (5, 25 or 50 mg·kg 1 ) reduced obviously the plasma TXB 2 level in rabbit with uncomplete cerebral ischemia (504±196, 386±174, or 272±183 vs 921±539 pg·ml 1 , respectively, P < 0.01). We conclude that the decrease of TXB 2 content is one of the possible mechanisms of Ber anti cerebral ischemic effect.展开更多
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 verapam...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.展开更多
Background Despite the proven benefits of clopidogrel combined aspirin therapy for coronary artery disease （CAD）, CAD patients with metabolic syndrome （MS） still tend to have coronary thrombotic events. We aimed t...Background Despite the proven benefits of clopidogrel combined aspirin therapy for coronary artery disease （CAD）, CAD patients with metabolic syndrome （MS） still tend to have coronary thrombotic events. We aimed to investigate the influence of metabolic risk factors on the efficacy of clopidogrel treatment in patients with CAD undergoing percutaneous coronary intervention （PCI）. Methods Cohorts of 168 MS and 168 non-MS subjects with CAD identified by coronary angiography （CAG） were enrolled in our study. MS was defined by modified Adult Treatment Panel Ⅲ criteria. All subjects had taken 100 mg aspirin and 75 mg clopidogrel daily for more than 1 month, and administered loading doses of 600 mg clopidogrel and 300 mg aspirin before PCI. Blood samples were taken 24 h after the loading doses of clopidogrel and aspirin. Platelet aggregation was measured using light transmittance aggregometry （LTA） and thrombelastography （TEG）. Clopidogrel resistance was defined as more than 50% adenosine diphosphate （ADP） induced platelet aggregation as measured by TEG. Re- sults Platelet aggregation inhibition rate by ADP was significantly lower in patients with MS as measured both by TEG （55% ＋ 31% vs. 68% ± 32%; P 〈 0.001） and LTA （29% ± 23% vs. 42% ± 29%; P 〈 0.001）. In the multivariate analysis, elderly [OR （95% CI）： 1.483 （1.047±.248）; P = 0.002], obesity [OR （95% CI）： 3.608 （1.241-10.488）; P = 0.018], high fasting plasma glucose level [OR （95% CI）： 2.717 （1.176±.277）; P = 0.019] and hyperuricemia [OR （95% CI）： 2.583 （1.095-6.094）; P = 0.030] were all statistically risk factors for clopido- grel resistance. CAD patients with diabetes and obesity were more likely to have clopidogrel resistance than the CAD patients without dia- betes and obesity [75% （61/81） vs. 43% （67/156）; P 〈 0.001]. Conclusions CAD patients with MS appeared to have poorer antiplatelet response to clopidogrel compared to those without MS. Obesity, diabetes and hyperuricemia were all significantly associated with clopido- grel resistance.展开更多
AIMTo evaluate the effect of sitagliptin vs placebo on histologic and non-histologic parameters of non-alcoholic steatohepatitis (NASH).METHODSTwelve patients with biopsy-proven NASH were randomized to sitagliptin (10...AIMTo evaluate the effect of sitagliptin vs placebo on histologic and non-histologic parameters of non-alcoholic steatohepatitis (NASH).METHODSTwelve patients with biopsy-proven NASH were randomized to sitagliptin (100 mg daily) (n = 6) or placebo (n = 6) for 24 wk. The primary outcome was improvement in liver fibrosis after 24 wk. Secondary outcomes included evaluation of changes in NAFLD activity score (NAS), individual components of NAS (hepatocyte ballooning, lobular inflammation, and steatosis), glycemic control and insulin resistance [including measurements of glycated hemoglobin (HbA1C) and adipocytokines], lipid profile including free fatty acids, adipose distribution measured using magnetic resonance imaging (MRI), and thrombosis markers (platelet aggregation and plasminogen activator inhibitor 1 levels). We also sought to determine the correlation between changes in hepatic fat fraction (%) [as measured using the Iterative Decomposition of water and fat with Echo Asymmetry and Least-squares estimation (IDEAL) MRI technique] and changes in hepatic steatosis on liver biopsy.RESULTSSitagliptin was not significantly better than placebo at reducing liver fibrosis score as measured on liver biopsy (mean difference between sitagliptin and placebo arms, 0.40, P = 0.82). There were no significant improvements evident with the use of sitagliptin vs placebo for the secondary histologic outcomes of NAS total score as well as for the individual components of NAS. Compared to baseline, those patients who received sitagliptin demonstrated improved HbA1C (6.7% ± 0.4% vs 7.9% ± 1.0%, P = 0.02), and trended towards improved adiponectin levels (4.7 ± 3.5 μg/mL vs 3.9 ± 2.7 μg/mL, P = 0.06) and triglyceride levels (1.26 ± 0.43 mmol/L vs 2.80 ± 1.64 mmol/L, P = 0.08). However, when compared with placebo, sitagliptin did not cause a statistically significant improvement in HbA1C (mean difference, -0.7%, P = 0.19) nor triglyceride levels (mean difference -1.10 mmol/L, P = 0.19) but did trend towards improved adiponectin levels only (mean difference, 0.60 μg/mL, P = 0.095). No significant changes in anthropometrics, liver enzymes, other adipocytokines, lipid profile, thrombosis parameters, or adipose distribution were demonstrated. The MRI IDEAL procedure correlated well with steatosis scores obtained on liver biopsy in both groups at baseline and post-treatment, and the Spearman correlation coefficients ranged from r = 0.819 (baseline) to r = 0.878 (post-treatment), P = 0.002.CONCLUSIONSitagliptin does not improve fibrosis score or NAS after 24 wk of therapy. The MRI IDEAL technique may be useful for non-invasive measurement of hepatic steatosis.展开更多
BM-13 505 is a new type of thromboxane receptor antagonist developed firstabfoad and synthesized in our school.wita modife method recently。The resultS of our study showed that the occlusion time of carotid artery in ...BM-13 505 is a new type of thromboxane receptor antagonist developed firstabfoad and synthesized in our school.wita modife method recently。The resultS of our study showed that the occlusion time of carotid artery in experimental thrombosis rats was prolonged by BM-13505,0.45 and 0.23 mglkg iv fP<0.00 1 and <0.01 respectively).B·13505 2 mgjkg iv ef fectively prevented the cerebral thrombosis caused by AA 4 mg/kg in rats(P<0.01) BM-13505 10 mg/kg ip prevented the AA-induced pulmonary thrombosis in mice(P<0.01).Tail bleeding time of mice was prolonged by this dru.BM-13505 significantly inhibited the AA-induced rabbit platelet aggregation,with an IC￣(50) of0.17 μmol/L; ADp-and collagen-induced aggregations were not affected.TXB_2 level in platelets and that in mice plasma were decreased by BM-13505,but cAMP level inplatelets was not affected. BM-13505 may be possibly developed into a useful anti-platelet and anti-thromboti c drug。展开更多
The antithrombotic and antiplatelet effects of two fucoidan fractions with low molecular weight and different sulfate content from Laminaria japonica were compared in order to examine the influence of chemical charact...The antithrombotic and antiplatelet effects of two fucoidan fractions with low molecular weight and different sulfate content from Laminaria japonica were compared in order to examine the influence of chemical character on their antithrombotic activity and the possible mechanism. Both LMW fucoidan fractions exhibited favorable antithrombotic activity in an Fecl3-induced arterial thrombosis. The antithrombotic activity of LMW fucoidan was related with decrease of TXB2 and whole blood viscosity and hematocrit. LMW fucoidan showed a correlation between anticoagulant, antiaggregant and antithrombotic effects in vivo. For LMW fucoidan, antithrombotic activity required high dose of 5-10 nmol kg-1, concomitantly with increase in anticoagulant activity and inhibition of platelet aggregation. Administration of LMW fucoidan significantly promoted the 6-keto-PGF1α content and decreased the TXB2 content, indicating its inhibition of tissue factor pathway and regulation of metabolism of arachidonic acid. By comparison, highly sulfated fucoidan LF2 with Mw 3900 seemed to be a more suitable choice for antithrombotic drug for its antithrombotic activity accompanied with specific inhibitory activity on platelet aggregation, low anticoagulant activity and low hemorrhagic risk in vivo.展开更多
Background Female patients with atrial fibrillation （AF） experience increased risk of thromboembolism compared to males, an observation that is reflected by its inclusion in the CHA2DS2VASc score. New onset AF （oft...Background Female patients with atrial fibrillation （AF） experience increased risk of thromboembolism compared to males, an observation that is reflected by its inclusion in the CHA2DS2VASc score. New onset AF （often associated with tachycardia） also confers upon patients increased thromboembolic risk. The mechanisms underlying this risk are uncertain, but new onset AF is associated with profound impairment of platelet nitric oxide （NO） signalling. Given that cardiovascular responses to catecholamines are gender-dependent, and that the presence of tachycardia in new onset AF may represent a response to catecholaminergic stimulation, we explored the potential impact of gender and tachycardia on platelet aggregation and NO signalling. Methods Interactions were sought in 87 AF patients between the extent of adenosine diphosphate （ADP）-induced platelet aggregation, the anti-aggregatory effects of the NO donor, sodium nitroprusside, gender, and admission heart rate. The potential impact of platelet expression of thioredoxin-interacting protein （Txnip） was also evaluated. Results Analysis ofcovariance confLrmed the presence of physiological antagonism between platelet ADP and NO responses [F （1, 74） = 12.212, P 〈 0.01 ], while female sex correlated with impaired NO responses independent of platelet aggregability [F （2, 74） = 8.313, P 〈 0.01]. Admission heart rate correlated directly with platelet aggregation （r = 0.235, P 〈 0.05）, and inversely with NO response （r = -0.331, P 〈 0.01）. Txnip expression varied neither with gender nor with heart rate. Conclusions These results indicate, that gender and heart rate are independent determinants of platelet fimction. Prospective studies of the putative benefit of reversal of tachycardia on restoration of normal platelet function are therefore a priority.展开更多
Twenty-one cases of acute cerebral infarction secondary to NIDDM were treated with acupuncture and conventional therapy, and compared with 16 cases treated with conventional therapy alone. The results showed that acup...Twenty-one cases of acute cerebral infarction secondary to NIDDM were treated with acupuncture and conventional therapy, and compared with 16 cases treated with conventional therapy alone. The results showed that acupuncture was more effective in reducing insulin and glucagon levels (P展开更多
Background Given the increasing number of patients who require dual antiplatelet （DAP） therapy and electrophysiological device （EPD） placement, perioperative antiplatelet management is a current challenge. In this...Background Given the increasing number of patients who require dual antiplatelet （DAP） therapy and electrophysiological device （EPD） placement, perioperative antiplatelet management is a current challenge. In this study, we investigated the incidence of pocket hema-toma formation after EPD placement in patients undergoing DAP therapy or an alternative low-molecular-weight heparin （LMWH） regimen. Methods This clinical observational study was performed from July 2010 to July 2012. In total, 171 patients were enrolled in the analysis after meeting the inclusion criteria. These patients were divided into two groups： 86 patients were treated with DAP therapy at the time of device implantation, and the DAP therapy was discontinued for 5 to 7 days and replaced with enoxaparin before device implantation in the other 85 patients. Adenosine phosphate （ADP）-mediated platelet aggregation and arachidonic acid-induced platelet aggregation were tested preoperatively. We compared the incidence of pocket hematoma between the two groups and the association of pocket hematoma develop-ment with ADP-mediated platelet aggregation and arachidonic acid-induced platelet aggregation.Results The incidence of pocket hema-toma in the patients who continued DAP was lower than that in the patients who replaced the dual antiplatelet regimen with LMWH （3.49%vs. 16.47%, respectively;X2 = 6.66,P 〈 0.01）. Among the patients who continued DAP therapies, the rate of ADP-mediated platelet aggre-gation inhibition in patients with pocket hematomas was higher than that in patients without pocket hematomas. None of the patients under-going DAP or enoxaparin therapy developed pocket infection, thromboembolic events, or other serious complications. Multiple logistic re-gression analysis revealed that LMWH therapy was an independent risk factor for the development of pocket hematoma （RR = 0.054, 95%CI = 0.012-0.251）. Furthermore, patients undergoing LMWH therapy were 5.1-fold more likely to develop pocket hematomas than were DAP-treated individuals.Conclusion Continuance of DAP therapy does not increase the risk of pocket hematoma formation after EPD placement.展开更多
Several studies have indicated that fucoidan fractions with low molecular weight and different sulfate content from Laminaria japonica could inhibit the activation of platelets directly by reducing the platelet aggreg...Several studies have indicated that fucoidan fractions with low molecular weight and different sulfate content from Laminaria japonica could inhibit the activation of platelets directly by reducing the platelet aggregation. To explore the direct effect of LMW fucoidan on the platelet system furthermore and examine the possible mechanism, the endothelial protection and inhibits platelet activation effects of two LMW fucoidan were investigated. In the present study, Endothelial injury model of rats was made by injection of adrenaline(0.4 mg kg-1) and human umbilical vein endothelial cells were cultured. v WF level was be investigated in vivo and in vitro as an important index of endothelial injury. LMW fucoidan could significantly reduce v WF level in vascular endothelial injury rats and also significantly reduce v WF level in vitro. The number of EMPs was be detected as another important index of endothelial injury. The results showed that LMW fucoidan reduced EMPs stimulated by tumor necrosis factor. In this study, it was found that by inhibiting platelet adhesion, LMW fucoidan played a role in anti-thrombosis and the specific mechanism of action is to inhibit the flow of extracellular Ca2+. All in a word, LMW fucoidan could inhibit the activation of platelets indirectly by reducing the concentration of EMPs and v WF, at the same time; LMW fucoidan inhibited the activation of platelets directly by inhibiting the flow of extracellular Ca2+.展开更多
基金This project was supported by the National Natural Science Foundation
文摘In an attempt to demonstrate the biological activities of a short peptide.Arg-Gly-Asp- Ser (RGDS) was synthesized and used for bioassay,The data obtained here proved that RGDS ob- viously inhibited PAF- and/or ADP-induced platelet aggregation.The present paper revealed that RG- DS had vasodilative action and the cGMP accumulation may be one of the mechanisms of RGDS exer- ting bioactivities.
文摘Effects of berberine (Ber) on platelet aggregation and TXB2 and 6 keto PGF1a plasma levels were studied in rabbits with uncomplete cerebral ischemia. Ber inhibited uncomplete cerebral ischemic rabbit platelet aggregation triggered by collagen, ADP, and arachidonic acid (AA) with the IC 50 of 0.15, 0.46, and 0.51 mg·ml 1 , respectively. In rabbits, Ber 25, or 50 mg·kg 1 iv 30 min after uncomplete cerebral ischemia, restrained the collagen ADP and AA induced platelet aggregation determined 90 min later. With radioimmunoassay, we measured the thromboxane B2 (TXB 2) and 6 ketoprostaglandin F 1α (6 keto PGF 1α ) contents in rabbit plasma. The results indicated that the TXB 2 level in rabbit 120 min after uncomplete cerebral ischemia (921±539 pg·ml 1 ) was higher than that (230±71 pg·ml 1 ) in normal rabbits ( P < 0.01), but 6 keto PGF 1α level after ischemia (73±23pg·ml 1 ) was lower than that (262±988pg·ml 1 ) in normal rabbit. Ber (5, 25 or 50 mg·kg 1 ) reduced obviously the plasma TXB 2 level in rabbit with uncomplete cerebral ischemia (504±196, 386±174, or 272±183 vs 921±539 pg·ml 1 , respectively, P < 0.01). We conclude that the decrease of TXB 2 content is one of the possible mechanisms of Ber anti cerebral ischemic effect.
文摘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.
文摘Background Despite the proven benefits of clopidogrel combined aspirin therapy for coronary artery disease （CAD）, CAD patients with metabolic syndrome （MS） still tend to have coronary thrombotic events. We aimed to investigate the influence of metabolic risk factors on the efficacy of clopidogrel treatment in patients with CAD undergoing percutaneous coronary intervention （PCI）. Methods Cohorts of 168 MS and 168 non-MS subjects with CAD identified by coronary angiography （CAG） were enrolled in our study. MS was defined by modified Adult Treatment Panel Ⅲ criteria. All subjects had taken 100 mg aspirin and 75 mg clopidogrel daily for more than 1 month, and administered loading doses of 600 mg clopidogrel and 300 mg aspirin before PCI. Blood samples were taken 24 h after the loading doses of clopidogrel and aspirin. Platelet aggregation was measured using light transmittance aggregometry （LTA） and thrombelastography （TEG）. Clopidogrel resistance was defined as more than 50% adenosine diphosphate （ADP） induced platelet aggregation as measured by TEG. Re- sults Platelet aggregation inhibition rate by ADP was significantly lower in patients with MS as measured both by TEG （55% ＋ 31% vs. 68% ± 32%; P 〈 0.001） and LTA （29% ± 23% vs. 42% ± 29%; P 〈 0.001）. In the multivariate analysis, elderly [OR （95% CI）： 1.483 （1.047±.248）; P = 0.002], obesity [OR （95% CI）： 3.608 （1.241-10.488）; P = 0.018], high fasting plasma glucose level [OR （95% CI）： 2.717 （1.176±.277）; P = 0.019] and hyperuricemia [OR （95% CI）： 2.583 （1.095-6.094）; P = 0.030] were all statistically risk factors for clopido- grel resistance. CAD patients with diabetes and obesity were more likely to have clopidogrel resistance than the CAD patients without dia- betes and obesity [75% （61/81） vs. 43% （67/156）; P 〈 0.001]. Conclusions CAD patients with MS appeared to have poorer antiplatelet response to clopidogrel compared to those without MS. Obesity, diabetes and hyperuricemia were all significantly associated with clopido- grel resistance.
基金the Physicians’Services Incorporated Foundation 10q2083(Joy TR and Beaton MD)Academic Medical Organization of Southwestern Ontario,No.F10-002(Beaton MD)+1 种基金partly funded through academic research funds from the Program of Experimental Medicine(Joy TR)Department of Medicine Academic Funds(Joy TR)from Western University,London,Ontario,Canada
文摘AIMTo evaluate the effect of sitagliptin vs placebo on histologic and non-histologic parameters of non-alcoholic steatohepatitis (NASH).METHODSTwelve patients with biopsy-proven NASH were randomized to sitagliptin (100 mg daily) (n = 6) or placebo (n = 6) for 24 wk. The primary outcome was improvement in liver fibrosis after 24 wk. Secondary outcomes included evaluation of changes in NAFLD activity score (NAS), individual components of NAS (hepatocyte ballooning, lobular inflammation, and steatosis), glycemic control and insulin resistance [including measurements of glycated hemoglobin (HbA1C) and adipocytokines], lipid profile including free fatty acids, adipose distribution measured using magnetic resonance imaging (MRI), and thrombosis markers (platelet aggregation and plasminogen activator inhibitor 1 levels). We also sought to determine the correlation between changes in hepatic fat fraction (%) [as measured using the Iterative Decomposition of water and fat with Echo Asymmetry and Least-squares estimation (IDEAL) MRI technique] and changes in hepatic steatosis on liver biopsy.RESULTSSitagliptin was not significantly better than placebo at reducing liver fibrosis score as measured on liver biopsy (mean difference between sitagliptin and placebo arms, 0.40, P = 0.82). There were no significant improvements evident with the use of sitagliptin vs placebo for the secondary histologic outcomes of NAS total score as well as for the individual components of NAS. Compared to baseline, those patients who received sitagliptin demonstrated improved HbA1C (6.7% ± 0.4% vs 7.9% ± 1.0%, P = 0.02), and trended towards improved adiponectin levels (4.7 ± 3.5 μg/mL vs 3.9 ± 2.7 μg/mL, P = 0.06) and triglyceride levels (1.26 ± 0.43 mmol/L vs 2.80 ± 1.64 mmol/L, P = 0.08). However, when compared with placebo, sitagliptin did not cause a statistically significant improvement in HbA1C (mean difference, -0.7%, P = 0.19) nor triglyceride levels (mean difference -1.10 mmol/L, P = 0.19) but did trend towards improved adiponectin levels only (mean difference, 0.60 μg/mL, P = 0.095). No significant changes in anthropometrics, liver enzymes, other adipocytokines, lipid profile, thrombosis parameters, or adipose distribution were demonstrated. The MRI IDEAL procedure correlated well with steatosis scores obtained on liver biopsy in both groups at baseline and post-treatment, and the Spearman correlation coefficients ranged from r = 0.819 (baseline) to r = 0.878 (post-treatment), P = 0.002.CONCLUSIONSitagliptin does not improve fibrosis score or NAS after 24 wk of therapy. The MRI IDEAL technique may be useful for non-invasive measurement of hepatic steatosis.
文摘BM-13 505 is a new type of thromboxane receptor antagonist developed firstabfoad and synthesized in our school.wita modife method recently。The resultS of our study showed that the occlusion time of carotid artery in experimental thrombosis rats was prolonged by BM-13505,0.45 and 0.23 mglkg iv fP<0.00 1 and <0.01 respectively).B·13505 2 mgjkg iv ef fectively prevented the cerebral thrombosis caused by AA 4 mg/kg in rats(P<0.01) BM-13505 10 mg/kg ip prevented the AA-induced pulmonary thrombosis in mice(P<0.01).Tail bleeding time of mice was prolonged by this dru.BM-13505 significantly inhibited the AA-induced rabbit platelet aggregation,with an IC￣(50) of0.17 μmol/L; ADp-and collagen-induced aggregations were not affected.TXB_2 level in platelets and that in mice plasma were decreased by BM-13505,but cAMP level inplatelets was not affected. BM-13505 may be possibly developed into a useful anti-platelet and anti-thromboti c drug。
基金supported in part by the Notional Natural Science Foundation of China (No.30800858)the Shandong Natural Science Foundation (No.ZR2010 CQ020)
文摘The antithrombotic and antiplatelet effects of two fucoidan fractions with low molecular weight and different sulfate content from Laminaria japonica were compared in order to examine the influence of chemical character on their antithrombotic activity and the possible mechanism. Both LMW fucoidan fractions exhibited favorable antithrombotic activity in an Fecl3-induced arterial thrombosis. The antithrombotic activity of LMW fucoidan was related with decrease of TXB2 and whole blood viscosity and hematocrit. LMW fucoidan showed a correlation between anticoagulant, antiaggregant and antithrombotic effects in vivo. For LMW fucoidan, antithrombotic activity required high dose of 5-10 nmol kg-1, concomitantly with increase in anticoagulant activity and inhibition of platelet aggregation. Administration of LMW fucoidan significantly promoted the 6-keto-PGF1α content and decreased the TXB2 content, indicating its inhibition of tissue factor pathway and regulation of metabolism of arachidonic acid. By comparison, highly sulfated fucoidan LF2 with Mw 3900 seemed to be a more suitable choice for antithrombotic drug for its antithrombotic activity accompanied with specific inhibitory activity on platelet aggregation, low anticoagulant activity and low hemorrhagic risk in vivo.
文摘Background Female patients with atrial fibrillation （AF） experience increased risk of thromboembolism compared to males, an observation that is reflected by its inclusion in the CHA2DS2VASc score. New onset AF （often associated with tachycardia） also confers upon patients increased thromboembolic risk. The mechanisms underlying this risk are uncertain, but new onset AF is associated with profound impairment of platelet nitric oxide （NO） signalling. Given that cardiovascular responses to catecholamines are gender-dependent, and that the presence of tachycardia in new onset AF may represent a response to catecholaminergic stimulation, we explored the potential impact of gender and tachycardia on platelet aggregation and NO signalling. Methods Interactions were sought in 87 AF patients between the extent of adenosine diphosphate （ADP）-induced platelet aggregation, the anti-aggregatory effects of the NO donor, sodium nitroprusside, gender, and admission heart rate. The potential impact of platelet expression of thioredoxin-interacting protein （Txnip） was also evaluated. Results Analysis ofcovariance confLrmed the presence of physiological antagonism between platelet ADP and NO responses [F （1, 74） = 12.212, P 〈 0.01 ], while female sex correlated with impaired NO responses independent of platelet aggregability [F （2, 74） = 8.313, P 〈 0.01]. Admission heart rate correlated directly with platelet aggregation （r = 0.235, P 〈 0.05）, and inversely with NO response （r = -0.331, P 〈 0.01）. Txnip expression varied neither with gender nor with heart rate. Conclusions These results indicate, that gender and heart rate are independent determinants of platelet fimction. Prospective studies of the putative benefit of reversal of tachycardia on restoration of normal platelet function are therefore a priority.
文摘Twenty-one cases of acute cerebral infarction secondary to NIDDM were treated with acupuncture and conventional therapy, and compared with 16 cases treated with conventional therapy alone. The results showed that acupuncture was more effective in reducing insulin and glucagon levels (P
文摘Background Given the increasing number of patients who require dual antiplatelet （DAP） therapy and electrophysiological device （EPD） placement, perioperative antiplatelet management is a current challenge. In this study, we investigated the incidence of pocket hema-toma formation after EPD placement in patients undergoing DAP therapy or an alternative low-molecular-weight heparin （LMWH） regimen. Methods This clinical observational study was performed from July 2010 to July 2012. In total, 171 patients were enrolled in the analysis after meeting the inclusion criteria. These patients were divided into two groups： 86 patients were treated with DAP therapy at the time of device implantation, and the DAP therapy was discontinued for 5 to 7 days and replaced with enoxaparin before device implantation in the other 85 patients. Adenosine phosphate （ADP）-mediated platelet aggregation and arachidonic acid-induced platelet aggregation were tested preoperatively. We compared the incidence of pocket hematoma between the two groups and the association of pocket hematoma develop-ment with ADP-mediated platelet aggregation and arachidonic acid-induced platelet aggregation.Results The incidence of pocket hema-toma in the patients who continued DAP was lower than that in the patients who replaced the dual antiplatelet regimen with LMWH （3.49%vs. 16.47%, respectively;X2 = 6.66,P 〈 0.01）. Among the patients who continued DAP therapies, the rate of ADP-mediated platelet aggre-gation inhibition in patients with pocket hematomas was higher than that in patients without pocket hematomas. None of the patients under-going DAP or enoxaparin therapy developed pocket infection, thromboembolic events, or other serious complications. Multiple logistic re-gression analysis revealed that LMWH therapy was an independent risk factor for the development of pocket hematoma （RR = 0.054, 95%CI = 0.012-0.251）. Furthermore, patients undergoing LMWH therapy were 5.1-fold more likely to develop pocket hematomas than were DAP-treated individuals.Conclusion Continuance of DAP therapy does not increase the risk of pocket hematoma formation after EPD placement.
文摘Several studies have indicated that fucoidan fractions with low molecular weight and different sulfate content from Laminaria japonica could inhibit the activation of platelets directly by reducing the platelet aggregation. To explore the direct effect of LMW fucoidan on the platelet system furthermore and examine the possible mechanism, the endothelial protection and inhibits platelet activation effects of two LMW fucoidan were investigated. In the present study, Endothelial injury model of rats was made by injection of adrenaline(0.4 mg kg-1) and human umbilical vein endothelial cells were cultured. v WF level was be investigated in vivo and in vitro as an important index of endothelial injury. LMW fucoidan could significantly reduce v WF level in vascular endothelial injury rats and also significantly reduce v WF level in vitro. The number of EMPs was be detected as another important index of endothelial injury. The results showed that LMW fucoidan reduced EMPs stimulated by tumor necrosis factor. In this study, it was found that by inhibiting platelet adhesion, LMW fucoidan played a role in anti-thrombosis and the specific mechanism of action is to inhibit the flow of extracellular Ca2+. All in a word, LMW fucoidan could inhibit the activation of platelets indirectly by reducing the concentration of EMPs and v WF, at the same time; LMW fucoidan inhibited the activation of platelets directly by inhibiting the flow of extracellular Ca2+.
