Biocompatibility is the essential property of biomaterials, which is the essence of biomaterial evaluation as well as the foundation of the design and improvement of biomaterials. Several methods were carried out to evaluate the biocompatibility of poly(L-Lactide)-b-poly(trimethylene carbonate (PLLA-b-PTMC) and poly(D,L-Lactide)-b-poly(trimethylene carbonate) (PDLLA-b-PTMC) with poly(L-Lactide) (PLLA) and poly(trimethylene carbonate) (PTMC) as control, including extract liquid experiment, directly contact experiment of materials and cells, hemolytic ratio analysis and platelet adhesion investigation. The results revealed that all the materials exhibited an acceptable cytotoxicity, and proliferation of cells on the modified materials was less than that on the PLLA but more than that on PTMC. The results of hemocompatibility experiments showed that no significant hemolysis was detected when all the materials were in use; in addition, the numbers of platelets adhered on the surface of copolymers were smaller than that on the surface of PLLA, and the degree of platelet deformation was slighter. So, the biocompatibility of copolymers is similar to that of PLLA, the biocompatibility of PLLA is not remarkably changed by modification with PTMC, but rather is improved.
Absorbable Implants ; Biocompatible Materials ; chemistry ; metabolism ; Blood Platelets ; cytology ; Hardness ; Humans ; Lactic Acid ; chemistry ; metabolism ; Materials Testing ; Polyesters ; chemistry ; metabolism ; Polymers ; chemistry ; metabolism ; Tissue Engineering ; methods

OBJECTIVETo explore whether normal platelet contains tissue factor (TF), and the significance of platelet-associated TF (PATF).

METHODSPlatelets were isolated by Sepharose 2B gel column. ELISA was used to detect the TF content in the lysates of washed platelets. Procoagulant activity of PATF was measured by one stage clotting time assay. The mRNA of TF was detected by reverse transcription polymerase chain reaction (RT-PCR).

RESULTSA certain amount of TF antigen (16.37 +/- 6.39) ng/L was detected in the washed-platelet lysates. Upon activation by collagen, platelets released TF and caused a marked increase in TF level in plasma (P <0.05). Resting platelets had no TF procoagulant activity, while procoagulant activity of platelets activated by collagen increased significantly, which could be blocked by TF McAb and poor VII plasma. TF mRNA could not be detected in washed platelets. TF content in platelets from patients with coronary heart disease was significantly higher than that from normal controls (P < 0.05). Resting platelets from the patients showed a higher procoagulant activity, which could be inhibited by TF McAb.

CONCLUSIONPlatelets contain TF and the latter released by activated platelet was functionally active. Platelet itself might not synthesize TF. Protein content and procoagulant activity of PATF in patients with coronary heart disease were higher than that in controls. All these indicate that platelet may be involved in coagulation and thrombosis by releasing TF.

Adolescent ; Adult ; Blood Platelets ; chemistry ; Coronary Artery Disease ; metabolism ; physiopathology ; Female ; Humans ; Male ; Middle Aged ; Platelet Activation ; Thromboplastin ; metabolism ; physiology

The study was purposed to investigate whether the cyclooxygenase inhibitors from some dietary vegetables can inhibit platelet aggregation function by the arachidonic acid (AA). The vegetable juice was mixed with platelet rich plasma (PRP), and asprin was used as positive control. The maximum ratio of platelet aggregation induced by AA was measured on the aggregometer; heme and cyclooxygenase-1 (COX(1)) or cyclooxygenase-2 (COX(2)) were added to test tubes containing COX reaction buffer, the mixture was vortex-mixed and exposed to aspirin or vegetable juice, followed by addition of AA and then hydrochloric acid (1 mol/L) was added to stop the COX reaction, followed by chemical reduction with stannous chloride solution. The concentration of COX inhibitors was detected by the enzyme immunoassay kit; vegetable juice (aspirin as positive control) was mixed with whole blood, which was followed by the addition of AA, and then the reaction was stopped by adding indomethacin, centrifuged, then the supernatant was collected, and the plasma thromboxane B(2) (TXB(2)) was measured by radioimmunoassay. The results showed that spinach juice, garlic bolt juice, blanched garlic leave juice and Chinese leek juice could inhibit by 80% human platelet aggregation induced by AA. 4 kinds of vegetables were all found a certain amount of cyclooxygenase inhibitors, which COX(1) and COX(2) inhibitor concentrations of spinach were higher than that of aspirin; 4 vegetable juice could significantly reduce the human plasma concentrations of TXB(2) induced by AA (p < 0.05). It is concluded that 4 kinds of raw vegetables containing cyclooxygenase inhibitors inhibit the production of TXA(2) and thus hinder platelet aggregation. Raw spinach, garlic bolt, blanched garlic and chinese leek inhibit significantly AA-induced human platelet aggregation in vitro. 4 kinds of vegetables may have a good potential perspective of anti-platelet aggregation therapy or prevention of thrombosis.
Adult ; Arachidonic Acid ; metabolism ; Blood Platelets ; drug effects ; Cyclooxygenase Inhibitors ; pharmacology ; Female ; Humans ; Male ; Platelet Aggregation ; drug effects ; Vegetables ; chemistry

Adult ; Aged ; Alanine Transaminase ; blood ; Blood Platelets ; chemistry ; Cholesterol ; blood ; Dietary Fats ; metabolism ; Fatty Acids ; blood ; Fatty Liver ; blood ; etiology ; metabolism ; pathology ; Female ; Humans ; Liver ; metabolism ; pathology ; Male ; Middle Aged ; Phospholipids ; blood ; Risk Factors ; Triglycerides ; blood

OBJECTIVETo study the effect of aqueous extract of several kinds of herbs on human platelet aggregation and expression of P-selectin in vitro.

METHODSBlood was collected from volunteers. Effects of the prepared water extracts of herbs on platelet aggregation were monitored on a Packs-4 aggregometer. The fluorescence intensity of water extracts of Caulis Spatholobi, Flos Carthami and Rhizoma Curcumae on the expression of P-selectin in human platelets of healthy persons was measured with flow cytometry.

RESULTSOut of several herbs investigated, Flos Carthami and Rhizoma Curcumae potently inhibited platelet aggregation after incubation with platelet-rich plasma (PRP) for 15 min. Caulis Spatholobi Flos Carthami and Rhizoma Curcumae inhibited adenosine-5'-diphosphate (ADP) or platelet activating factor (PAF)-induced platelet aggregation in PRP in a dose-dependent manner. In contrast to Flos Carthami and Rhizoma Curcumae, Caulis Spatholobi could not inhibit thrombin-induced platelet aggregation. Despite its inability to inhibit thrombin-induced platelet aggregation in PRP, Caulis Spatholobi had a greater anti-aggregating activity in PRP induced by ADP or PAF. Caulis Spatholobi and Flos Carthami showed significant inhibitory effects on the expression of P-selectin.

CONCLUSIONSCaulis Spatholobi, Flos Carthami and Rhizoma Curcumae have potent anti-platelet properties, and their inhibitory actions are mediated via different mechanisms. Caulis Spatholobi inhibited ADP-induced platelet aggregation but not by thrombin, indicating that its mechanism of action might be independent of the thromboxane pathway. The effect of Caulis Spatholobi and Flos Carthami were associated with suppressing the expression of P-selectin.

Adult ; Blood Platelets ; drug effects ; metabolism ; Curcuma ; chemistry ; Fabaceae ; chemistry ; Humans ; P-Selectin ; metabolism ; Plant Extracts ; chemistry ; pharmacology ; Plants, Medicinal ; chemistry ; Platelet Aggregation ; drug effects ; Platelet Function Tests ; Water ; chemistry ; Young Adult

OBJECTIVETo investigate the clinical effect of Erigeron injection (El) on positive expression rate of CD62p in platelet and content of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in serum of patients with acute cerebral infarction (ACI).

METHODSSixty-eight patients with ACI were randomly divided into the treated group (n = 35) and the control group (n = 33). Conventional treatment were given to both groups, and EI 40 ml/d were given additionally to the treated group, the treatment course for both groups was 15 days. The positive expression of platelet CD62p and the serum TNF-alpha and IL-6 in patients before and after treatment were determined with flow cytometric (FCM) and electrochemical-luminescence (ECL) techniques respectively.

RESULTSThe total curative effect in the treated group were significantly higher than that in the control group (P < 0.05). Levels of platelet CD62p and serum TNF-alpha and IL-6 in ACI patients before and after treatment were significant higher than those in the healthy group (P < 0.05), all the three parameters were significantly decreased after treatment, and the lowering in the treated group was more significant than that in the control group (P < 0.05).

CONCLUSIONThe effect of El on ACI patients may relate to its action in down-regulating the expression of platelet CD62p, alleviating the immune response and inflammatory injury of central nervous system induced by cytokines.

Aged ; Aged, 80 and over ; Asteraceae ; chemistry ; Blood Platelets ; metabolism ; Cerebral Infarction ; immunology ; metabolism ; Drugs, Chinese Herbal ; therapeutic use ; Female ; Humans ; Injections ; Interleukin-6 ; blood ; Male ; Middle Aged ; P-Selectin ; biosynthesis ; blood ; Phytotherapy ; Tumor Necrosis Factor-alpha ; metabolism

BACKGROUND: Standard protocols are lacking for the preparation of platelet lysates (PL) as an alternative to using fetal bovine serum as a cell culture supplement. This study aimed to establish optimum conditions for preparing PL for use in cell cultures. METHODS: Cell density in three pooled platelet concentrates (PC) were adjusted to 1x10(12)/L and 2x10(12)/L. PL was prepared from PC by 1 to 3 freeze-thaw (FT) cycles. HaCaT cells were cultured in media supplemented with 5% or 10% PL. Cell numbers were estimated using a Cell Counting Kit-8 (CCK-8; Dojindo Laboratories, Japan). Growth factors were quantified by using the Luminex 200 system (Luminex Corporation, USA). RESULTS: Cell proliferation rates in the presence of PLs were similar when prepared from PCs of both cell densities. The rates were higher in media containing 5% PL than 10% PL when prepared by two FT cycles. Concentrations of vascular endothelial growth factor (VEGF), platelet-derived growth factor-AB/BB (PDGF-AB/BB), PDGF-AA, and epidermal growth factor (EGF) were significantly higher in PL prepared from PC with a cell density of 2x10(12)/L than 1x10(12)/L PC. However, only VEGF and PDGF-AA concentrations in PLs were correlated with HaCaT cell counts. CONCLUSIONS: The 5% PL from PC with a cell density of 1x10(12)/L prepared by two FT cycles treatment was the most effective condition that supported steady HaCaT cell proliferation. Our finding may be useful for preparing PL-supplemented cell culture media.
Blood Platelets/chemistry/*metabolism ; Cell Line ; Cell Proliferation/drug effects ; Culture Media/pharmacology ; Epidermal Growth Factor/chemistry/pharmacology ; Humans ; Platelet-Derived Growth Factor/chemistry/pharmacology ; Vascular Endothelial Growth Factor A/chemistry/pharmacology

This study was designed to investigate inhibitory effects and possible mechanisms of snake venom tripeptide (pENW) on platelet adhesion in order to promote the development of a novel anti-platelet therapy. To study the inhibitory effects of pENW on platelet adhesion, washed platelets pre-incubated with pENW (116.5-466.2 μmol x L(-1)) were used to test the ability of platelet adhesion to fibrinogen. Effect of pENW on fibrin clot retraction was also tested. Effect of pENW on platelets viability was tested by MTT assay. Effect of pENW on reactive-oxygen species (ROS) levels of platelet was studied by flow cytometry assay. Calcium mobilization in Fura-2/AM-loaded platelets was monitored with a spectrofluorimeter. Cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP), thromboxane A2 (determined as its metabolite thromboxane B2) were measured using enzyme immunoassay kits. Akt, ERK and p38 phosphorylation were tested by Western blot. The results showed that pENW inhibited platelet adhesion and fibrin clot retraction in a concentration-dependent manner without cytotoxicity. Intracellular cGMP and cAMP in both resting and thrombin-activated platelets were increased by pENW. In addition, pENW attenuated intracellular Ca2+ mobilization and TXA2 production in platelets stimulated by thrombin. As shown by Western blot assay, Akt, ERK and p38 phosphorylation in thrombin-induced platelet were attenuated by pENW. However, inhibitory effects of pENW had nothing to do with ROS. Thus, pENW exhibited a significant inhibition on platelet adhesion to fibrinogen, which means pENW could block the first step of thrombosis as while as retard the more stable clot formation. The mechanisms of pENW on inhibition platelet adhesion might be related to instant regulations, such as protein kinases.
Blood Platelets ; drug effects ; Blotting, Western ; Calcium ; metabolism ; Cyclic AMP ; metabolism ; Cyclic GMP ; metabolism ; Flow Cytometry ; Phosphorylation ; Platelet Aggregation ; drug effects ; Reactive Oxygen Species ; metabolism ; Snake Venoms ; chemistry ; Thromboxane A2 ; metabolism ; Thromboxane B2 ; metabolism

CHO cells expressing human GPIb/IX and rabbit red blood cells coated with human von Willebrand factor (VWF) were adapted to our study on the binding probability and the detachment force of GPIb/IX and VWF. With the micropipette system, the two cells were impinged under a constant force for controlled time. When the cells were pulled apart, the deformation of RBC was recorded, and the binding score and detachment force of the proteins were determined. After the two cells were impinged into 0.5 microm for 30 s, the binding probability of the two cells carrying GPIb/IX and VWF was 15.0%. Via analyzing the deformation of red blood cells, we found out the distribution of rupture forces of cells with GPIb/IX and VWF. Therefore, we infer that the continuous distribution of the detachment force is due to the stochastic effect. The most probable value of the detachment force was 10 pN.
Animals ; Binding Sites ; Blood Platelets ; metabolism ; CHO Cells ; Cell Adhesion ; Cricetinae ; Cricetulus ; Humans ; Platelet Activation ; physiology ; Platelet Glycoprotein GPIb-IX Complex ; chemistry ; metabolism ; Rabbits ; von Willebrand Factor ; chemistry ; metabolism

AIMTo observe the effect of phenolic alkaloids of Menispermum dauricum (PAMD) on thrombosis and platelet aggregation, and to explore its mechanism of action.

METHODSThrombosis was observed with arteriovenous shunt thrombus model in rat; platelet aggregation was determined by Born's method; ultrastructure of platelet was observed by transmission electron microscope; TXB2 or 6-keto-PGF1alpha levels were assessed by radioimmunoassay; and NO was determined by colorimetric method.

RESULTSPAMD dose-dependently inhibited experimental thrombus formation, platelet aggregation induced by ADP, AA and THR in vivo and ultrastructure changes stimulated by THR; PAMD increased the generation of 6-keto-PGF1alpha in thoracic aortae and NO level in plasma; and had no influence on TXB2 release (P > 0.05).

CONCLUSIONPAMD inhibited thrombosis and platelet aggregation, and its mechanism might be due to the increase of PGI2 and NO level.

6-Ketoprostaglandin F1 alpha ; metabolism ; Alkaloids ; administration & dosage ; isolation & purification ; pharmacology ; Animals ; Aorta, Thoracic ; metabolism ; Benzylisoquinolines ; administration & dosage ; isolation & purification ; pharmacology ; Blood Platelets ; ultrastructure ; Dose-Response Relationship, Drug ; Epoprostenol ; metabolism ; Male ; Menispermum ; chemistry ; Nitric Oxide ; blood ; Plants, Medicinal ; chemistry ; Platelet Aggregation ; drug effects ; Rabbits ; Rats ; Rats, Sprague-Dawley ; Rhizome ; chemistry ; Tetrahydroisoquinolines ; administration & dosage ; isolation & purification ; pharmacology ; Thrombosis ; metabolism ; Thromboxane B2 ; metabolism