scholarly journals Preparation, Physicochemical Properties, and Hemocompatibility of the Composites Based on Biodegradable Poly(Ether-Ester-Urethane) and Phosphorylcholine-Containing Copolymer

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 860 ◽  
Author(s):  
Jun Zhang ◽  
Bing Yang ◽  
Qi Jia ◽  
Minghui Xiao ◽  
Zhaosheng Hou
Keyword(s):  
Physicochemical Properties ◽  
Tensile Properties ◽  
Platelet Rich Plasma ◽  
Composite Films ◽  
Homogeneous Solution ◽  
Uniform Size ◽  
Good Surface ◽  
Biodegradable Poly ◽  
Ether Ester

To improve the hemocompatibility of the biodegradable medical poly(ether-ester-urethane) (PEEU), containing uniform-size aliphatic hard segments that was prepared in our lab, a copolymer containing phosphorylcholine (PC) groups was blended with the PEEU. The PC-copolymer of poly(MPC-co-EHMA) (PMEH) was first obtained by copolymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) and 2-ethylhexyl methacrylate (EHMA), and then dissolved in mixed solvent of ethanol/chloroform to obtain a homogeneous solution. The composite films (PMPU) with varying PMEH content were prepared by solvent evaporation method. The physicochemical properties of the composite films with varying PMEH content were researched. The PMPU films exhibited higher thermal stability than that of the pure PEEU film. With the PMEH content increasing from 5 to 20 wt%, the PMPU films also possessed satisfied tensile properties with ultimate stress of 22.9–15.8 MPa and strain at break of 925–820%. The surface and bulk hydrophilicity of the films were improved after incorporation of PMEH. In vitro degradation studies indicated that the degradation rate increased with PMEH content, and it took 12–24 days for composite films to become fragments. The protein adsorption and platelet-rich plasma contact tests were adapted to evaluate the surface hemocompatibility of the composite films. It was found that the amount of adsorbed protein and adherent platelet on the surface decreased significantly, and almost no activated platelets were observed when PMEH content was above 5 wt%, which manifested good surface hemocompatibility. Due to the biodegradability, acceptable tensile properties and good surface hemocompatibility, the composites can be expected to be applied in blood-contacting implant materials.

scholarly journals Degradable Poly(ether-ester-urethane)s Based on Well-Defined Aliphatic Diurethane Diisocyanate with Excellent Shape Recovery Properties at Body Temperature for Biomedical Application

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1002 ◽  
Author(s):  
Minghui Xiao ◽  
Na Zhang ◽  
Jie Zhuang ◽  
Yuchen Sun ◽  
Fang Ren ◽  
...  
Keyword(s):  
Body Temperature ◽  
Shape Memory ◽  
Tensile Properties ◽  
Shape Recovery ◽  
Biomedical Application ◽  
Degradation Products ◽  
Chain Extension ◽  
Chemical Structures ◽  
Ether Ester

The aim of this study is to offer a new class of degradable shape-memory poly(ether-ester-urethane)s (SMPEEUs) based on poly(ether-ester) (PECL) and well-defined aliphatic diurethane diisocyanate (HBH) for further biomedical application. The prepolymers of PECLs were synthesized through bulk ring-opening polymerization using ε-caprolactone as the monomer and poly(ethylene glycol) as the initiator. By chain extension of PECL with HBH, SMPEEUs with varying PEG content were prepared. The chemical structures of the prepolymers and products were characterized by GPC, 1H NMR, and FT-IR, and the effect of PEG content on the physicochemical properties (especially the shape recovery properties) of SMPEEUs was studied. The microsphase-separated structures of the SMPEEUs were demonstrated by DSC and XRD. The SMPEEU films exhibited good tensile properties with the strain at a break of 483%–956% and an ultimate stress of 23.1–9.0 MPa. Hydrolytic degradation in vitro studies indicated that the time of the SMPEEU films becoming fragments was 4–12 weeks and the introduction of PEG facilitates the degradation rate of the films. The shape memory properties studies found that SMPEEU films with a PEG content of 23.4 wt % displayed excellent recovery properties with a recovery ratio of 99.8% and a recovery time of 3.9 s at body temperature. In addition, the relative growth rates of the SMPEEU films were greater than 75% after incubation for 72 h, indicating good cytocompatibility in vitro. The SMPEEUs, which possess not only satisfactory tensile properties, degradability, nontoxic degradation products, and cytocompatibility, but also excellent shape recovery properties at body temperature, promised to be an excellent candidate for medical device applications.

Thrombin Generation Assessment in Platelet Rich Plasma Offers Additional Criteria for Low Molecular Weight Heparin Antithrombotic Fingerprint Characterization.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4177-4177
Author(s):  
Grigorios T. Gerotziafas ◽  
Galea Vasso ◽  
Jeanine M. Walenga ◽  
Evi Kalodiki ◽  
Mourad Chaari ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Physicochemical Properties ◽  
Thrombin Generation ◽  
Platelet Rich Plasma ◽  
Inhibitory Effect ◽  
Low Molecular Weight ◽  
Generation Process ◽  
Health Authorities ◽  
The Impact

Abstract Abstract 4177 Introduction National and international organizations recognize that low molecular weight heparins (LMWHs) are distinct entities and that they should not be used interchangeably in clinical practice. Physicochemical properties, such as molecular weight anti-Xa/anti-IIa ratios, are used by health authorities to establish LMWHs differentiation. LMWHs are multitargeted drugs in which small differences in physicochemical properties may lead to significantly different inhibition of blood coagulation. In the present in vitro study we have investigated if thrombin generation assay, reflecting the overall coagulation process, is a suitable tool for the LMWH variability evalution. Materials and methods LMWHs (bemiparin, enoxaparin, nadroparin, dalteparin and tinzaparin) and unfractionated heparin (UFH) were added in vitro in normal citrated platelet rich plasma from 10 healthy individuals, at clinically relevant concentrations (ranging from 0.2 to 1 anti-Xa IU/ml). Thrombin generation was studied with Thrombogram-Thrombinoscope® assay using diluted thromboplastin (Innovin®, 1/1000 final dilution, Siemens France). The concentrations doubling the lag-time, the time to Peak, the IC50 for Peak, the endogenous thrombin potential (ETP) and the mean rate index of propagation phase (MRI) were determined for each compound. Results LMWHs compared on their anti-Xa activity basis showed variable inhibitory effect on thrombin generation. At equivalent anti-Xa concentrations tinzaparin was significantly more potent than the other LMWHs, being almost similar to UFH profile. Enoxaparin, nadroparin and dalteparin showed a similar inhibitory activity. Bemiparin had the lesser pronounced inhibitory effect on thrombin generation. The impact of anti-Xa and anti-IIa activities on each phase of thrombin generation process is different. Thrombogram chronometric parameters are mainly influenced by the anti-IIa activity. Similarly, ETP inhibition depends more on anti-IIa rather than anti-Xa activity. The MRI of the propagation phase is more sensitive to the anti-Xa activity of LMWHs. Conclusion Thrombin generation assessment in platelet rich plasma allows to evaluate the anticoagulant fingerprint of LMWHs and to differentiate them on global and functional criteria. Each LMWH has a particular inhibitory impact on each phase of thrombin generation process. These functional criteria need to be standardized and probably required for a better characterization of LMWHs heterogeneity by health authorities. They could be used also to evaluate bioequivalence of generic and original LMWHs. Disclosures: No relevant conflicts of interest to declare.

Enhancement of ADP-induced Platelet Aggregation by Adrenaline in Vivo and Its Prevention

1973 ◽  
Vol 29 (02) ◽  
pp. 490-498 ◽  
Author(s):  
Hiroh Yamazaki ◽  
Itsuro Kobayashi ◽  
Tadahiro Sano ◽  
Takio Shimamoto
Keyword(s):  
Platelet Count ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
The Other ◽  
Endothelial Surface ◽  
Important Interaction ◽  
Blood Coagulability ◽  
The Difference

SummaryThe authors previously reported a transient decrease in adhesive platelet count and an enhancement of blood coagulability after administration of a small amount of adrenaline (0.1-1 µg per Kg, i. v.) in man and rabbit. In such circumstances, the sensitivity of platelets to aggregation induced by ADP was studied by an optical density method. Five minutes after i. v. injection of 1 µg per Kg of adrenaline in 10 rabbits, intensity of platelet aggregation increased to 115.1 ± 4.9% (mean ± S. E.) by 10∼5 molar, 121.8 ± 7.8% by 3 × 10-6 molar and 129.4 ± 12.8% of the value before the injection by 10”6 molar ADP. The difference was statistically significant (P<0.01-0.05). The above change was not observed in each group of rabbits injected with saline, 1 µg per Kg of 1-noradrenaline or 0.1 and 10 µg per Kg of adrenaline. Also, it was prevented by oral administration of 10 mg per Kg of phenoxybenzamine or propranolol or aspirin or pyridinolcarbamate 3 hours before the challenge. On the other hand, the enhancement of ADP-induced platelet aggregation was not observed in vitro, when 10-5 or 3 × 10-6 molar and 129.4 ± 12.8% of the value before 10∼6 molar ADP was added to citrated platelet rich plasma (CPRP) of rabbit after incubation at 37°C for 30 second with 0.01, 0.1, 1, 10 or 100 µg per ml of adrenaline or noradrenaline. These results suggest an important interaction between endothelial surface and platelets in connection with the enhancement of ADP-induced platelet aggregation by adrenaline in vivo.

Storage of Human Blood Platelets

1974 ◽  
Vol 32 (02/03) ◽  
pp. 405-416 ◽  
Author(s):  
M. R Hardeman ◽  
Carina J L. Heynens
Keyword(s):  
Storage Temperature ◽  
Platelet Rich Plasma ◽  
Blood Platelets ◽  
Storage Period ◽  
Serotonin Uptake ◽  
Hypotonic Shock ◽  
Glycolytic Intermediates

SummaryStorage experiments were performed at 4°, 25° and 37° C with platelet-rich plasma under sterile conditions. In some experiments also the effect of storing platelets at 4° C in whole blood was investigated.Before, during and after three days of storage, the platelets were tested at 37° C for their serotonin uptake and response to hypotonic shock. In addition some glycolytic intermediates were determined.A fair correlation was noticed between the serotonin uptake and hypotonic shock experiments. Both parameters were best maintained at 25° C. Also platelet counting, performed after the storage period, indicated 25° C as the best storage temperature. Determination of glycolytic intermediates did not justify any conclusion regarding the optimal storage temperature. Of the various anticoagulants studied, ACD and heparin gave the best results as to the serotonin uptake and hypotonic shock response, either with fresh or stored platelets. The use of EDTA resulted in the lowest activity, especially after storage.The results of these storage experiments in vitro, correspond well with those in vivo reported in the literature.

The Effect of Lysed Platelets on Neutralization of Heparin In Vitro with Protamine as Measured by the Activated Coagulation Time (ACT)

1991 ◽  
Vol 66 (02) ◽  
pp. 213-217 ◽  
Author(s):  
Arthur P Bode ◽  
William J Castellani ◽  
Edna D Hodges ◽  
Susan Yelverton
Keyword(s):  
Platelet Rich Plasma ◽  
Coagulation Time ◽  
Platelet Factor ◽  
Platelet Suspension ◽  
Antiheparin Activity ◽  
Unit Increase ◽  
Heparin Anticoagulation ◽  
Heparin Activity ◽  
Activated Coagulation Time

SummaryThe effect of lysed platelets on the activated coagulation time (ACT) was studied in heparinized whole blood during titration with protamine. Frozen-thawed washed platelet suspension, or a chromatography fraction thereof, or autologous frozen-thawed platelet-rich plasma was added in various dilutions to freshly drawn blood anticoagulated with 3,000 USP units/1 heparin. After a 10 min incubation, the amount of protamine needed to restore the ACT to baseline ("protamine titration dose") was determined. We found that the protamine titration dose decreased in proportion to the amount of lysed platelet material added; expressed as a percentage of the total number of platelets present, each unit increase in lysed platelets produced a 1.7% ±0.8 (SD) reduction in the protamine dose needed to normalize the ACT. A heparin activity assay showed that this effect was not due to antiheparin activity of lysed platelets such as platelet factor 4 (PF4). Our data indicate that the procoagulant activity of platelet membranes reduced the sensitivity of the ACT to heparin. These findings suggest that membranous platelet microparticles may cause an inaccurate calculation, based on the ACT, of a protamine dose to reverse heparin anticoagulation in cardiopulmonary bypass procedures.

Haemostatic Platelet Plug Formation in the Isolated Rabbit Mesenteric Preparation - An Analysis of Red Blood Cell Participation

1980 ◽  
Vol 44 (01) ◽  
pp. 006-008 ◽  
Author(s):  
D Bergqvist ◽  
K-E Arfors
Keyword(s):  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Adenosine Diphosphate ◽  
In Vitro Test ◽  
Pharmacological Agents ◽  
Vitro Test ◽  
Releasing Effect ◽  
Plug Formation

SummaryIn a model using an isolated rabbit mesenteric preparation microvessels were transected and the time until haemostatic plugs formed was registered. Perfusion of platelet rich plasma gave no haemostasis whereas whole blood did. Addition of chlorpromazine or adenosine to the whole blood significantly prolonged the time for haemostasis, and addition of ADP to the platelet rich plasma significantly shortened it. It is concluded that red cells are necessary for a normal haemostasis in this model, probably by a combination of a haemodynamic and ADP releasing effect.The fundamental role of platelets in haemostatic plug formation is unquestionable but there are still problems concerning the stimulus for this process to start. Three platelet aggregating substances have been discussed – thrombin, adenosine diphosphate (ADP) and collagen. Evidence speaking in favour of thrombin is, however, very minimal, and the discussion has to be focused on collagen and ADP. In an in vitro system using polyethylene tubings we have shown that "haemostasis" can be obtained without the presence of collagen but against these results can be argued that it is only another in vitro test for platelet aggregation (1).To be able to induce haemostasis in this model, however, the presence of red blood cells is necessary. To further study this problem we have developed a model where haemostatic plug formation can be studied in the isolated rabbit mesentery and we have briefly reported on this (2).Thus, it is possible to perfuse the vessels with whole blood as well as with platelet rich plasma (PRP) and different pharmacological agents of importance.

Effect of Aspirin on the Thrombelastogram of Human Blood

1973 ◽  
Vol 30 (03) ◽  
pp. 494-498 ◽  
Author(s):  
G de Gaetano ◽  
J Vermylen
Keyword(s):  
Oral Dose ◽  
Single Oral Dose ◽  
Platelet Function ◽  
Human Blood ◽  
Platelet Rich Plasma ◽  
Plasma Samples ◽  
Release Reaction ◽  
Platelet Release

SummaryThrombelastograms of both native blood and re-calcified platelet-rich plasma samples taken from subjects given a single oral dose of aspirin (1 gram) were not significantly different from the pretreatment recordings. Aspirin also did not modify the thrombelastogram when preincubated in vitro with platelet-rich plasma at concentrations inhibiting the platelet “release reaction” by collagen. Thrombelastography therefore cannot evaluate the effect of aspirin on platelet function.

Reaction of Acetaldehyde with Human Platelets

1992 ◽  
Vol 67 (01) ◽  
pp. 126-130 ◽  
Author(s):  
Olivier Spertini ◽  
Jacques Hauert ◽  
Fedor Bachmann
Keyword(s):  
Platelet Aggregation ◽  
Inhibitory Action ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
Shape Change ◽  
Reaction Medium ◽  
Human Platelets ◽  
Membrane Glycoproteins ◽  
Neutral Ph

SummaryPlatelet function defects observed in chronic alcoholics are not wholly explained by the inhibitory action of ethanol on platelet aggregation; they are not completely reproduced either in vivo by short-term ethanol perfusion into volunteers or in vitro by the addition of ethanol to platelet-rich plasma. As acetaldehyde (AcH) binds to many proteins and impairs cellular activities, we investigated the effect of this early degradation product of ethanol on platelets. AcH formed adducts with human platelets at neutral pH at 37° C which were stable to extensive washing, trichloracetic acid hydrolysis and heating at 100° C, and were not reduced by sodium borohydride. The amount of platelet adducts formed was a function of the incubation time and of the concentration of AcH in the reaction medium. At low AcH concentrations (<0.2 mM), platelet bound AcH was directly proportional to the concentration of AcH in the reaction medium. At higher concentrations (≥0.2 mM), AcH uptake by platelets tended to reach a plateau. The amount of adducts was also proportional to the number of exposures of platelets to pulses of 20 pM AcH.AcH adducts formation severely impaired platelet aggregation and shape change induced by ADP, collagen and thrombin. A positive correlation was established between platelet-bound AcH and inhibition of aggregation.SDS-PAGE analysis of AcH adducts at neutral pH demonstrated the binding of [14C]acetaldehyde to many platelet proteins. AcH adduct formation with membrane glycoproteins, cytoskeleton and enzymes might interfere with several steps of platelet activation and impair platelet aggregation.This in vitro study shows that AcH has a major inhibitory action on platelet aggregation and may account for the prolonged ex vivo inhibition of aggregation observed in chronic alcoholics even in the absence of alcoholemia.

A Comparison of the in Vitro and in Vivo Thrombogenic Activity of Factor IX Concentrates Using Stasis (Wessler) and Non-Stasis Rabbit Models

1980 ◽  
Vol 44 (02) ◽  
pp. 081-086 ◽  
Author(s):  
C V Prowse ◽  
A E Williams
Keyword(s):  
Platelet Rich Plasma ◽  
Thrombus Formation ◽  
Factor Ix ◽  
Coagulation System ◽  
In Vitro Tests ◽  
Clinical Use ◽  
Low Activity

SummaryThe thrombogenic effects of selected factor IX concentrates were evaluated in two rabbit models; the Wessler stasis model and a novel non-stasis model. Concentrates active in either the NAPTT or TGt50 in vitro tests of potential thrombogenicity, or both, caused thrombus formation in the Wessler technique and activation of the coagulation system in the non-stasis model. A concentrate with low activity in both in vitro tests did not have thrombogenic effects in vivo, at the chosen dose. Results in the non-stasis model suggested that the thrombogenic effects of factor IX concentrates may occur by at least two mechanisms. A concentrate prepared from platelet-rich plasma and a pyrogenic concentrate were also tested and found to have no thrombogenic effect in vivo.These studies justify the use of the NAPTT and TGt50 in vitro tests for the screening of factor IX concentrates prior to clinical use.

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