Effect of Platelet Activation and Endothelial Cell Injury on Malignant Cancer

Objective: To study the effects of platelet activation and endothelial cell injury on the patients with malignant tumor and their prognoses.Methods: Radioimmunity and ELISA methods were employed to detect the TXB2, GMP-140, vWF, cGMP and FN in 78 cases of malignant tumor and 40 healthy control persons.Results: The levels of TXB2, MP-140 and cGMP were increased in intestinal cancer group, lung cancer group and hepatic cancer group, while FN decreased in intestinal cancer and lung cancer group. cGMP was positively related to TXB2, GMP-140, vWF in malignant tumor group. FN was decreased in the group complicated with infection and the group with metastasis, while the other indexes increased. GMP-140, vWF and cGMP was decreased after operation except for the increasing of FN.Conclusion: Activations of platelet and injury of endothelial cells developed in patients with malignant tumor, and both of them affected the metastasis and prognosis of malignant tumor. Key words platelet activation - epithelium injury - malignant tumor - metastasis This work was supported by grants from Guangdong Medical Science foundation (A2000633).

Lipopolysaccharide-induced cerebral inflammatory damage and the therapeutic effect of platelet activating factor receptor antoganist

Objective To investigate lipopolysaccharide （LPS） induced acute cerebral inflammatory damage and the therapeutic effect of ginkgolide B （BN52021）. Methods Thirty Sprague-Dawley rats were randomly divided into 3 groups （n = 10 for each group）： Control group, Model group and Treatment group （treated with BN52021）. LPS were injected into the fourth ventricle of rat to make a neuroinflammatory murine model. Morris water maze was used to detect the learning and memory ability of rats; changes of synapse number and subcellular ultrastructures were observed under a transmission electron microscope; OX-42 positive microglia in the brain was detected by immunohistochemical method. Results The average escape latency in the Treatment group were significantly shortened than that in the Model group; and the percentage of swimming distance traveled in platform quadrant accounting for total distance increased markedly. The rough endoplasmic reticulum and polyribosomes in the Treatment group were more than that in the Model group, but the number of synapses seemed to have no obvious change. The number of OX-42 positive microglia in the Treatment group decreased markedly than that in the Model group, and the grey density of OX-42-positive cells increased significantly. Conclusion LPS can induce inflammatory damages to the brain, but the damage could be antagonized by BN52021. Platelet activating factor receptor antagonist may offer an effective therapy for neurodegeneration diseases.

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.

Significance of platelet activating factor receptor expression in pancreatic tissues of rats with severe acute pancreatitis and effects of BN52021

AIM:To investigate the dynamic changes and significance of platelet activating factor receptor (PAF-R) mRNA and protein in pancreatic tissues of rats with severe acute pancreatitis (SAP) and effects of BN52021 (Ginkgolide B). METHODS:Wistar male rats were randomly assigned to the negative control group (NC group),SAP model group (SAP group),and BN52051-remedy group (BN group),and each of the groups was divided into 6 subgroups at different time points after operation (1 h,2 h,3 h,6 h,12 h,and 24 h) (n=10 in each). PT-PCR and Western blot methods were used to detect PAF-RmRNA and protein expression in pancreatic tissues of rats respectively. Pathological examination of pancreatic tissues was performed and the serum amylase change was detected. RESULTS:Serum amylase and pathological results showed the that SAP model was successfully prepared,BN52021 was able to decrease serum amylase,and the pathological ratings in BN group at 3 h,6 h,and 12 h significantly decreased compared with those in the SAP group (8.85 ± 0.39 vs 5.95 ± 0.19,9.15 ± 0.55 vs 5.55 ± 0.36,10.10 ± 0.65 vs 6.72 ± 0.30,P < 0.05). The result of PAF-mRNA showed dynamic changes in SAP and BN groups,which increased gradually in early stage,reached a peak at 3 h (0.71 ± 0.14 vs 0.54 ± 0.14,0.69 ± 0.13 vs 0.59 ± 0.04,P < 0.05),and decreased gradually later. There were significant differences at each time point except 1 h and 2 h,when compared with those in the NC group (0.71 ± 0.14 or 0.69 ± 0.13 vs 0.47 ± 0.10,0.38 ± 0.08 or 0.59 ± 0.04 vs 0.47 ± 0.09,0.25 ± 0.07 or 0.29 ± 0.05 vs 0.46 ± 0.10,0.20 ± 0.06 or 0.20± 0.04 vs 0.43 ± 0.09,P < 0.05),whereas there was no significant difference between BN and SAP groups at each time point. The result of PAF-R protein showed that the change of PAF-R protein in the SAP group and the BN group was consistent with that of PAF-R mRNA. There were significant differences at each time point except 1 h,when compared with those in the NC group (0.90 ± 0.02 or 0.80 ± 0.05 vs 0.48 ± 0.02,1.69 ± 0.06 or 1.58 ± 0.02 vs 0.48 ± 0.03,1.12 ± 0.10 or 0.98 ± 0.03 vs 0.49 ± 0.09,1.04 ± 0.14 or 0.87 ± 0.02 vs 0.52 ± 0.08,0.97 ± 0.16 or 0.90 ± 0.05 vs 0.49 ± 0.10,P < 0.05),whereas there was no significant difference between the BN group and the SAP group. CONCLUSION:PAF-R plays an important role in occurrence and development of SAP. BN52021 exerts biological effects through competitively inhibiting the binding of increased both PAF and PAF-R expression rather than through decreasing PAF-R expression in pancreatic tissues.

Effect of Buyang Huanwu Decoction on Platelet Activating Factor Content in Arterial Blood Preand Post-Arterial Thrombosis in Rats

To explore the effect of Buyang Huanwu Decoction (BHD) on platelet activating factor (PAF) content in arterial blood pre- and post-arterial thrombosis in rats, male Wistar rats were randomly divided into 3 groups, the medicine group treated with BHD, the control group with dexamethasone liquid, and the blank group with distilled water. Oral administration was given for 14 consecutive days, once daily. Model of arterial thrombosis was established in the animals 2 hours after final medication, the blood content of PAF, dry weight (DW) and occlusion time (OT) of thrombus, and dry weight of thrombus/body weight (TW/BW) ratio were observed. Results indicated that BHD could markedly lower the arterial blood content of PAF after thrombosis, increase the OT of thrombus, reduce the dry weight of thrombus and the TW/BW ratio (P

Effect of increased hepatic platelet activating factor and its receptor portal hypertension in CCl_4-induced liver cirrhosis

AIM： To evaluate the changes in hepatic platelet activating factor （PAF） and its receptors and their effect on portal pressure of cirrhotic rats induced by CCh. METHODS： A model of liver cirrhosis was replicated in rats by intra-peritoneal injection of CCh for 8 wk. We determined the effect of hepatic PAF and its receptor level on portal and arterial pressure by EIA, saturation binding and RT-PCR technique. RESULTS： Compared to control rats, cirrhotic rats had higher hepatic PAF levels and output as well as higher plasma PAF levels （P〈0.01, P〈0.01, P〈0.05, respectively）. Both hepatic PAF receptor mRNA levels and PAF binding were nearly 3-fold greater in cirrhotic rats （P〈0.01）. Portal injection of PAF （1 g/kg WT） increased the portal pressure by 22% and 33% in control and cirrhotic rats, respectively. In contrast, the arterial pressure was decreased in the both groups （54% in control rats and 42% in cirrhotic rats）. Injection of the PAF antagonist BN52021 （5 mg/kg WT） decreased the portal pressure by 16% in cirrhotic rats but had no effect in the control rats. CONCLUSION： The upregulation of the PAF system contributes to hepatic hemodynamic and metabolic abnormalities in drrhosis, and the increased release of PAF into the circulation has impacts on the systemic hemodynamics.

Synthesis of platelet-activating factor and its receptor expression in Kupffer cells in rat carbon tetrachloride-induced cirrhosis

AIM:To determine the platelet-activating factor (PAF) synthesis and its receptor expression in Kupffer cells in rat carbon tetrachloride-induced cirrhosis. METHODS:Kupffer cells, isolated from the livers of control and CCl4-induced cirrhotic rats, were placed in serum-free medium overnight. PAF saturation binding, ET-1 saturation and competition binding were assayed. ET-1 induced PAF synthesis, mRNA expression of PAF, preproendothelin-1, endothelin A (ETA) and endothelin B (ETB) receptors were also determined. RESULTS:A two-fold increase of PAF synthesis (1.42 ± 0.14 vs 0.66 ± 0.04 pg/μg DNA) and a 1.48-fold increase of membrane-bound PAF (1.02 ± 0.06 vs 0.69 ± 0.07 pg/μg DNA) were observed in activated Kupffer cells of cirrhotic rats. The application of ET-1 to Kupffer cells induced PAF synthesis in a concentration-dependent manner in both cirrhotic and normal rats via ETB receptor, but PAF synthesis in the activated Kupffer cells was more effective than that in the normal Kupffer cells. In activated Kupffer cells, PAF receptor expression and PAF binding capacity were markedly enhanced. Activated Kupffer cells raised the [125I]-ET-1 binding capacity, but changed neither the affinity of the receptors, nor the expression of ETA receptor. CONCLUSION:Kupffer cells in the course of CCl4-induced cirrhosis are the main source of increased PAF. ET-1 is involved endogenously in stimulating the PAF synthesis in activated Kupffer cells via ETB receptor by paracrine. ETA receptor did not appear in activated Kupffer cells, which may exacerbate the hepatic and extrahepatic complications of cirrhosis.

Elevated Platelet Activating Factor Level in Ischemia-Related Arrhythmia and Its Electrophysiological Effect on Myocardium

Objective The mechanism through which platelet activating factor （PAF） induces cardiac electrical activity and arrhythmia is not well understood and previous studies have suggested a potential involvement of ion channels in its action. The present study was aimed to clarify the role of PAF in fatal arrhythmias following acute myocardia infarction （AMI） and the underlying mechanism. Methods （1） Blood PAF levels were measured among 72 AMI patients at the time of diagnosis with AMI and 48 h later, and their electrocardiogram （ECG） was recorded continuously. （2） Ischemia simulation and surface electrocardiogram were conducted in 20 pigs and their PAF levels were measured. （3） PAF perfusion and standard microelectrode recording were performed on guinea pig papillarymuscles. Results In both humans and pigs, elevated PAF levels were detected in AMI and simulated ischemia, respectively, and even higher PAF levels were found when fatal arrhythmias occurred. In guinea pig myocardium, PAF induced a shortening of action potential duration at 90% level of repolarization （APD 90 ）under non-ischemic conditions and a more pronounced shortening under early simulated ischemic conditions. Conclusion AMI and ischemia are associated with increased PAF levels in humans and pigs, which are further raised when fatal arrhythmia follows. The effects of PAF on the myocardium may be mediated by multiple ion channels.

Hepatic stellate cells may be potential effectors of platelet activating factor induced portal hypertension

AIM: To determine platelet activating factor (PAF) receptor expression in cirrhotic hepatic stellate cells.METHODS: Hepatic stellate cells, isolated from the livers of control and CCl4-induced cirrhotic rats, were placed in serum-free medium after overnight culture. We determined the PAF receptor in hepatic stellate cells by saturation binding technique and semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), and the effects of PAF and its antagonist BN52021 on prostaglandin E2 (PGE2) release by stellate cells.RESULTS: Scatchard analysis indicated the presence of PAF receptor with dissociation constant (Kd) of 4.66 nmol/L and maximum binding capacity (Bmax) of 24.65 fmol/μg in cirrhotic stellate cells. Compared with the control, the maximum PAF binding capacity increased significantly (Bmax: 24.65 ± 1.96 fmol/μg. DNA, R = 0.982 vs 5.74 ± 1.55 fmol/μg. DNA, R = 0.93; P < 0.01), whereas receptor affinity had no significant difference (Kd of 4.66 ± 0.33 nmol/L for the cirrhosis and 3.51 ± 0.26 nmol/L for the control; P > 0.05). Consistent with the receptor binding data, the mRNA expression of PAF receptor was increased significantly in cirrhotic stellate cells. PAF in a concentration-dependent manner induced PGE2 synthesis in cirrhotic hepatic stellate cells, but the effects were blocked significantly by BN52021.CONCLUSION: Cirrhosis sensitizes hepatic stellate cells to PAF by elevating its receptor level and hepatic stellate cells maybe potential effectors of PAF induced portal hypertension.

Increased levels of circulating platelet-derived microparticles in psoriasis:Possible implications for the associated cardiovascular risk

AIM To evaluate platelet activation markers in psoriasis patients, compared to controls, and investigate their association with the inflammatory burden of psoriasis.METHODS Forty psoriatic patients without cardiovascular disease,and 12 healthy controls were subjected to measurement of baseline platelet CD62 P, CD63 and CD42 b expression, platelet-leukocyte complexes, i.e., platelet-monocyte complexes(PMC), platelet-neutrophil complexes(PNC) and platelet-lymphocyte complexes, and concentrations of platelet-derived microparticles(PMPs) using flow cytometry. Both larger-size(0.5-0.9 μm) and smallersize(< 0.5 μm) PMPs were determined. Serum interleukin(IL)-12 and IL-17 levels were also measured by enzyme-linked immunosorbent assay. The severity of psoriasis was evaluated by the Psoriasis Area Severity Index(PASI).RESULTS PMP concentrations were significantly higher in psoriasis patients than controls [mean±standard error of mean(SEM): 22±5/μL vs 11±6/μL; P=0.018), for both smaller-size(10±2/μL vs 4±2/μL; P=0.033) and larger-size(12±3/μL vs 6±4/μL; P=0.014) PMPs. Platelet CD62 P, CD63 and CD42 b expression and circulating PMC and PNC were similar between the two groups. Lower circulating PLC were observed in psoriasis patients compared to controls(mean±SEM: 16%±3% vs 23%±6%; P=0.047). Larger-size PMPs were related with IL-12 levels(P<0.001) and smaller-size PMPs with both IL-12 and IL-17 levels(P<0.001). Total PMPs also correlated with IL-12(P<0.001). CD63 expression was positively correlated with both IL-12 and IL-17(P<0.05). Increased PASI score was associated with increased levels of larger-size PMPs(r=0.45; P=0.011) and increased CD63 expression(r=0.47; P<0.01).CONCLUSION PMPs, known to be predictive of cardiovascular outcomes, are increased in psoriasis patients, and associated with high inflammatory disease burden. Enhanced platelet activation may be the missing link leading to cardiovascular events in psoriatic patients.

DETECTION OF PLATELET-DERIVED MICROPARTICLES USING FLOW CYTOMETRY AND ITS CLINICAL APPLICATION

Objective.To establish a flow cytometric internal standard method for counting platelet-derived microparti-cles(PMPs)and to study its clinical significance. Methods. PMPs suspension(platelet poor plasma,PPP) was extracted by gradual centrifugation. According to the size of PMPs,3 μm and 0.8μm latex beads were used as internal standards for the quantitation. PMPs were counted by adjusting flow cytometric discrimination and voltage of forward scatter and side scatter. Results. In 30 healthy donors,the average concentration of resting PMPs was(1.2×105±5.7×104 )/ml and that of activated PMPs was(1.6×106±9.1×105)/ml. Compared with healthy donors,PMPs mean value was significantly higher(P< 0.001)in 18 patients with coronary artery disease,12 with acute cerebral infraction and 23 with chronic renal failure[the average PMPs concentration,( 6.1×105±2.5×105 )/ml, ( 6.8×105±3.4×105)/ml and(5.9×105±3.1×105)/ml respectively]. However,no significant difference in PMPs concentration was observed in 25 patients with acute leukemia and severe thrombocytopenia during the aplastic phase after chemotherapy [1.3×105±6.1×104)/ml,(P >0.05)] .Conclusions. PMPs is a useful indicator in monitoring platelet activation,and plays an important role in thrombotic disease. By flow cytometric internal standard method,PMPs can be counted rapidly and accurately,which may be very helpful in interlaboratory comparative studies.

Creation of reversed phase high-performance liquid chromatographic technique to assay platelet-activating factor

Objective: To establish a new assay for platelet-activating factor (PAF), to compare it with bio-assay; and to discuss its significance in some elderly people diseases such as cerebral infarction and coronary heart disease. Methods: To measure PAF levels in 100 controls, 23 elderly patients with cerebral infarction and 65 cases with coronary heart disease by reversed phase high-performance liquid chromatographic technique (rHPLC). Results:rHPLC is more convenient, sensitive,specific, and less confusing, compared with bio-assay. The level of plasma PAF in patients with cerebral infarction was higher than that in the controls (P<0.01), and in patients with coronary heart disease. Conclusion: Detection of PAF with rHPLC is more reliable and more accurate. The new assay has important significance in PAF research.

Sequential expression of cyclooxygenase-2, glutamate receptor-2, and platelet activating factor receptor in rat hippocampal neurons after fluid percussion injury

Traumatic brain injury causes gene expression changes in different brain regions. Occurrence and development of traumatic brain injury are closely related, involving expression of three factors, namely cyclooxygenase-2, glutamate receptor-2, and platelet activating factor receptor. However, little is known about the correlation of these three factors and brain neuronal injury. In this study, primary cultured rat hippocampal neurons were subjected to fluid percussion injury according to Scott’s method, with some modifications. RT-PCR and semi-quantitative immunocytochemical staining was used to measure the expression levels of cyclooxygenase-2, glutamate receptor-2, and platelet activating factor receptor. Our results found that cyclooxygenase-2 expression were firstly increased post-injury, and then decreased. Both mRNA and protein expression levels reached peaks at 8 and 12 hours post-injury, respectively. Similar sequential changes in glutamate receptor 2 were observed, with highest levels mRNA and protein expression at 8 and 12 hours post-injury respectively. On the contrary, the expressions of platelet activating factor receptor were firstly decreased post-injury, and then increased. Both mRNA and protein expression levels reached the lowest levels at 8 and 12 hours post-injury, respectively. Totally, our findings suggest that these three factors are involved in occurrence and development of hippocampal neuronal injury.

Relationship and significance between anti-b2-glycoproteinⅠantibodies and platelet activation state in patients with ulcerative colitis

AIM： To study the relationship between anti-β2- glycoprotein Ⅰ （aβ2GPⅠ） antibodies and platelet activation state in patients with ulcerative colitis （UC） and its significance. METHODS： Peripheral blood samples were collected from 56 UC patients （34 males and 22 females, aged 43.5 years, range 21-66 years）, including 36 at active stage and 20 at remission stage, and 25 sex-and age-matched controls. The level of aβ2GP Ⅰ was measured by ELISA. The platelet activation markers, platelet activation complex- Ⅰ （PAC- Ⅰ ） and P-selectin （CD62P） were detected by flow cytometry. RESULTS： The A value for IgG aβ2GP Ⅰ in the active UC group was 0.61 ± 0.13, significantly higher than that in the remittent UC and control groups （0.50 ± 0.13 and 0.22 ± 0.14, P 〈 0.01）. There was a significant difference between the two groups （P 〈 0.01）. The A value for IgM aβ2GP Ⅰ in the active and remittent UC groups was 0.43 ± 0.13 and 0.38 ± 0.12, significantly higher than that in the control group （0.20 ± 0.12, P 〈 0.01）. However, there was no significant difference between the two groups （P 〉 0.05）. The PAC- Ⅰ positive rate for the active and remittent UC groups was 30.6% ± 7.6% and 19.6% ± 7.8% respectively, significantly higher than that for the control group （6.3% ± 1.7%,P 〈 0.01）. There was a significant difference between the two groups （P 〈 0.01）. The CD62P positive rate for the active and remittent UC groups was 45.0% ± 8.8% and 31.9% ± 7.8% respectively, significantly higher than that for the control group （9.2% ± 2.7%, P 〈 0.01）. There was a significant difference between the two groups （P 〈 0.01）. In the active UC group, the more severe the state of illness was, the higher the A value for IgG aβ2GP Ⅰ was, and the positive rate for PAC-Ⅰ and CD62P was positively correlated with the state of illness （Faβ2GP Ⅰ = 3.679, P 〈 0.05; FPAC-Ⅰ （%） = 5.346, P 〈 0.01; and FCD62P （%） = 5. 418, P 〈 0.01）. Meanwhile, in the same state of illness, the A value for IgG aβ2GP Ⅰ was positively correlated to the positive rates for PAC-Ⅰ and CD62P. CONCLUSION： aβ2GP Ⅰ level, platelet activation state and their relationship of them are closely correlated with the pathogenesis and development of UC.

Role of platelet TLR4 expression in pathogensis of septic thrombocytopenia

BACKGROUND： Infection-induced thrombocytopenia （TCP） is an independent risk factor for death of patients with sepsis, but its mechanism is unknown. This study aimed to explore the underlying mechanism of TCP based on the relationship between TLR4 expression and platelet activation in septic patients. METHODS： A total of 64 patients with sepsis were prospectively studied. Platelet count （PC）, mean platelet volume （MPV）, platelet distribution width （PDW）, platelet TLR4 expression, platelet PAC-1 expression, sCD40L and TNF-a concentrations were compared between the healthy control group （15 volunteers） and sepsis group （64 patients） at admission and on the 3, 5, and 9 days after admission. The changes of MPV and PDW in the TCP and non-TCP subgroups of sepsis before and after treatment were recorded. Prognostic index was analyzed. RESULTS：PC was lower in the sepsis group （P=0.006）, and MPV and PDW were higher in the sepsis group than those in the healthy control group （P=0.046, P=0.001）. Platelet TLR4 and PAC-1 expressions, and sCD40L and TNF-a levels increased more significantly in the sepsis group （P〈0.001）. PAC-1 expression and TNF-a level were higher in the TCP group than in the non-TCP group before and after treatment （P=0.023, P=0.011）. sCD40L concentration and platelet TLR4 expression were significantly higher in the treated TCP group than in the non-TCP group （P=0.047, P=0.001）. Compared to the non-TCP group, the rate of bleeding was higher （P=0.024） and the length of ICU stay was longer （P=0.013）. The APACHE II score and the 28-day mortality were higher in the TCP group （P〈0.01, P=0.048）. CONCLUSIONS：The elevation of platelet TLR4 expression in sepsis along with platelet activation is closely related to the incidence of thrombocytopenia. The occurrence of TCP is a sign of poor prognosis in sepsis patients.

In vitro effects of buyang huanwu decoction and its ingredients on inhibiting the specific binding of ~3H-platelet activating factor to its receptor in rabbits

BACKGROUND： Pharmacologic action of traditional Chinese medicine compound is the comprehensive effect of various ingredients, and the interactions of various ingredients are closely correlated with the final effect. In order to reveal the compatibility mechanism of buyang huanwu decoction （BHD）＇s prescription in treating and preventing ischemic cerebrovascular disease, we need to explore the effect and relation of ingredients in prescription except for considering the effect of each ingredient on the whole prescription. OBJECTIVE： To study the effect of BHD and its ingredients in the prescription on the specific binding of 3H-platelet activating factor （PAF） to its receptor （PAFR）in rabbits in vitro, and to analyze the action of each ingredient in the prescription. DESIGN： A decomposed recipe study based on orthogonal test. SETTING： Guangzhou University of Traditional Chinese Medicine. MATERIALS： Five healthy adult New Zealand rabbits of either gender were provided by the Experimental Animal Center of Guangzhou University of Traditional Chinese medicine. The prescription herbal pieces were purchased from Foshan Kangpu Pharmaceuticals Company and Jianmin Pharmaceuticals Company, and were appraised by Professor Yanchen Xu from College of Traditional Chinese Medicine, Guangzhou University of Traditional Chinese Medicine. 3H-PAF was supplied by Amersham Co,Ltd.（Specific activity： 6.475 TBq/mmol;batch number：200402）; PAF standard by Biomol Co., Ltd.（batch number： P1318V）. METHODS： This experiment was carried out in the Laboratory of Nuclear Medicine, Guangzhou University of Traditional Chinese Medicine between September and December 2004. ①The seven influencing factors were selected： such as Shenghuangqi , Dangguiwei, Chishao, Dilong, Taoren, Honghua, Chuanxiong. Each factor was divided into two levels, selected or not selected. The tests were arranged according to L8 （27） orthogonal test table. ②The specific binding of 3H-PAF to its receptors in rabbits was measured by radioligand binding assay. The inhibitory rate of the specific binding was used as an assessing index. The inhibitory action of and on 3H-PAF to PAFR binding was analyzed and compared in vitro. The inhibitory action of each ingredient in the prescription BHD on 3H-PAF to PAFR binding was investigated and compared in vitro by direct analysis and analysis of variance of orthogonal test. MAIN OUTCOME MEASURES： Effect of 8 prescriptions for L8 （27） orthogonal test table on the specific binding inhibition rate of 3H-PAF and PAFR. RESULTS： According to results of variance analysis of orthogonal test, the inhibitory action of each ingredient in the prescription BHD on 3H-PAF to PAFR binding from the highest to the lowest was in turn Honghua, ShenghuangqL Taoren, Dilong, DangguiweL Chuanxiong, Chishao. Honghua, Shenghuangqi, Taoren, Dilong, Danguiwei were major influence factors to 3H-PAF to PAFR in rabbits （F = 187.829,144.446,59.521,5.018,4.265, P 〈 0.05- 0.01）, but Chuanxiong and Chishao had not obviously inhibitory effect. The specific binding inhibition rate of prescriptions （except Shenghuangqi ） was obviously higher than that of one of prescriptions （Shenghuangqi included）. CONCLUSION： The results of orthogonal test show that Honghua, ShenghuangqL Taoren, Dilong, Dangguiwei are major influencing factors to inhibit binding of sH-PAF to PAFR in rabbits, among which, Honghua is the strongest in ingredients of prescription BHD. The results also reveal that Shenghuangqi is able to weaken the inhibitory effect and to prevent the strong inhibitory effect of blood-activating drugs in BHD.

Vascular dysfunctions and platelet activations by arsenic: two major contributing factors to cardiovascular disease

Arsenic in drinking water is a worldwide health problem that is associated with cardiovascular disease, but the cause is currently unknown. In order to examine whether arsenic affects vasomotor tone in blood vessels, we investigated the effect of arsenic on agonist-induced vasorelaxation and vasoconstriction using the isolated rat aortic rings in in vitro organ bath system. Treatment with inorganic arsenite (AsⅢ) inhibited acetylcholine-induced relaxation of aortic rings by inhibiting production of nitric oxide in endothelium.

Effects of Buyang Huanwu decoction and Astragalus mongholicus on platelet activating factor receptor activity in rabbits in vitro

BACKGROUND: The pharmacological action of traditional Chinese medicine compound is the comprehensive effect of the various ingredients, and the interactions of various ingredients are closely correlated with the final effect. In order to reveal the compatibility mechanism of BHD's prescription in treating and preventing ischemic cerebrovascular disease, we needed explore the effect and relation of ingredients in the prescription. OBJECTIVE: To observe the effect of Buyang Huanwu decoction (BHD) and Astragalus mongholicus on the activity of platelet activating factor receptor (PAFR) in the platelet of rabbits in vitro, and investigate the mechanism of Astragalus mongholicus. DESIGN: A decomposed recipes study. SETTING: Guangzhou University of Traditional Chinese Medicine. MATERIALS: Five New Zealand rabbits, weighing 2-3 kg, both sexes, were used. BHD was composed of Sheng Huang Qi 120 g, Dang Gui Wei 6 g, Chi Shao 4.5 g, Chuan Xiong 3 g, Di Long 3 g, Tao Ren 3 g, Hong Hua 3 g. The prescription for activating blood circulation consisted of Dang Gui Wei 6 g, Chi Shao 4.5 g, Chuan Xiong 3 g, Di Long 3 g, Tao Ren 3 g and Hong Hua 3 g. The prescription for invigorating qi consisted of 120 g Sheng Huang Qi. The prepared herbal pieces were purchased from the traditional Chinese medicine Dispensary of Foshan Second People's Hospital, and appraised by Professor Xu from Science of Chinese Materia Medica College, Guangzhou University of Traditional Chinese Medicine. 3H-PAF was supplied by Amersham Co., Ltd. (specific activity: 6. 475 TBq/mmol; batch number: 200402); PAF standard by Biomol Co., Ltd. (batch number: P1318V). METHODS: The experiments were carried out in the Laboratory of Nuclear Medicine, Guangzhou University of Traditional Chinese Medicine from September to December 2004. ① Injections of BHD, prescriptions for activating blood circulation and invigorating qi were prepared by the decoction and alcohol sedimentation technique. Rabbit common carotid artery blood (40 mL) was drawn via intubation to prepare platelet suspension of (0.8-1.0)×1010 L-1. ② Determination of 3H-PAF and washed PAFR binding: The general combination tube (T) contained washed platelet-rich plasma (WPRP) 380 μL + 3H-PAF (0.35 nmol/L)10 μL+distilled water 5 μL; The nonspecific binding tube (P) contained WPRP 380 μL+3H-PAF(0.35 nmol/L)10 μL+cold PAF (1 μmol/L) 5 μL; The sample tube (Y) contained WPRP 380 μL+3H-PAF(0.35 nmol/L)10 μL+experimental medicine (injection of BHD, prescriptions for activating blood circulation or invigorating qi) 5 μL. The test was conducted for three times for each sample in the same way as mentioned above. The samples were shaken on the oscillator for 30 s, then bathed at 25 ℃ for 40 minutes, and the reaction was terminated with cold Tris buffer containing 0.1% BSA, multichannel cell detachment separator was used for vacuum suction to filter the separated free 3H-PAF, and the filter paper was washed with cold Tris buffer for four times, then dried in the baking oven (80 ℃) for 1 hour, and placed in xylol liquid scintillator, and the radioactivity was determined automatically by the liquid scintillation detector. The mean of the three parallel tubes was calculated. The specific binging inhibition rate was calculated: SBIR=[(T-Y)/(T-P)]×100%]. ③ Univariate analysis of variance was conducted. And for comparison of each paired groups, the q test was adopted. MAIN OUTCOME MEASURES: Effect of BHD whole prescription, prescriptions for activating blood circulation and invigorating qi on the specific binding inhibition rate of 3H-PAF and PAFR. RESULTS: BHD, prescriptions for activating blood circulation and invigorating qi were all able to inhibit the specific binding of 3H-PAF to PAFR, the specific blinding inhibition rates were (45.90±7.50)%, (97.90±1.84)% and (26.75±2.48)%, respectively, and there were significant differences between every two groups (P < 0.01). CONCLUSION: Single Astragalus mongholicus (120 g) can inhibit the specific blinding of PAFR in the platelet of the rabbit with 3H-PAF, but the combination of Astragalus mongholicus with the drugs for activating blood circulation in BHD can significantly decrease the inhibiting action of the latter on PAFR activity of the platelet, reflecting the combined mechanism of 'removing blood stasis without injuring the vital qi' in BHD.

A Notable Platelet Activation Receptor--CLEC-2

In 1995,Huang et al.reported that rhodocytin,asnake toxin purified from callosdasma rhodostoma venomstimulates platelet aggregation.Ten years later,Suzuki-Inoue et al.identified C-type lectin-like receptor 2(CLEC-2)on platelets as the rhodocytin receptor.Thereafter,several studies have showed that platelet CLEC-2 isinvolved in lymphatic/blood vessel separation,tumormetastasis and thrombus formation.

Whole blood platelet aggregometry in HIV-infected patients on treatment with abacavir

Purpose: To assess platelet activity in HIV-patients with and without antiretroviral therapy (ART), analysing the influence of the presence or absence of ABC in the regimen. Methods: Observational, pilot study, including 30 asymptomatic HIV-patients: 20 on ART for at least 24 weeks and with undetectable HIV viral load - 10 on ABC, 10 on tenofovir (TDF) - and 10 na?ve patients, and a control group of 10 HIV-negative subjects. No subject was receiving drugs with antiagregant activity. Platelet activity was assessed by measuring time-dependent platelet aggregometry (electrical impedance on fasting whole blood), induced by ADP (1.25, 2.5 μM), collagen (0.5, 1 μg/mL), arachidonic acid (100, 200 μM), and U46619 (receptor agonist of the tromboxano A2) (1.25, 2.5 μM). Statistic program: SPSS, 16.0. Results: Demographic, anthropometric data, and cardiovascular risk factors were similar in all groups, but older age and longer time of HIV infection in the ABC group (50.4 vs 36.1, 34.2 and 42.7 years, respectively;p < 0.05, and 140.3 vs 88.1 and 48.3 months in the two other groups of HIV patients;p < 0.05). Mean CD4 cells count was 564/mm3. Platelet aggregation with exposure to U46619 was higher in the ABC compared with the TDF group (11.1 vs 4.4%;p = 0.007), na?ve patients (11.1 vs 5.7%;p = 0.014), and the HIV-negative group (11.1 vs 6.5%;p = 0.04). These differences remained significant when controlled for age and time of HIV infection. Conclusions: ABC increases platelet aggregability possibly in relation with the receptor of tromboxano. Wider studies are needed to confirm this hypothesis.