Tantalum-containing mesoporous bioactive glass powder for hemostasis

2020 ◽  
pp. 088532822096515
Author(s):  
Malvika Nagrath ◽  
Reid Gallant ◽  
Alireza Rahimnejad Yazdi ◽  
Andrew Mendonca ◽  
Saidur Rahman ◽  
...  
Keyword(s):  
Zeta Potential ◽  
Blood Coagulation ◽  
Intrinsic Pathway ◽  
Extrinsic Pathway ◽  
Bioactive Glasses ◽  
In Vitro Methods ◽  
Hemostatic Agents ◽  
Negative Zeta Potential ◽  
Mesoporous Bioactive Glass

This study evaluates the hemostatic properties of tantalum-containing mesoporous bioactive glasses (Ta-MBGs) through a suite of in-vitro methods: hemolysis percentage, zeta potential, blood coagulation assays (Activated Partial Thromboplastin Time – APTT and Prothrombin Time - PT) and cytotoxicity tests. Five compositions of Ta-MBG, with x mol% Ta2O5 added to the glass series (80- x)SiO2-15CaO-5P2O5- xTa2O5 where x=0 (0Ta), x=0.5 (0.5Ta), x=1 (1Ta), x=5 (5Ta), and x=10 (10Ta) mol%, were synthesised. The hemostatic potential of all the Ta-MBGs was confirmed by their negative zeta potential (–23 to –31 mV), which enhances the intrinsic pathway of blood coagulation. The hemolysis percentages of all Ta-MBGs except 10Ta showed statistically significant reductions compared to the same experiments carried out both in the absence of a sample (‘no treatment’ group) and in the presence of 10Ta. These observations validate the consideration of Ta-MBGs as hemostatic agents as they do not cause significant lysis of red blood cells. Cytotoxicity analysis revealed that Ta-MBGs had no effect on bovine fibroblast viability. Furthermore, a reduction in both APTT (a test to evaluate the intrinsic pathway of coagulation) and PT (a test to evaluate the extrinsic pathway) signified enhancement of hemostasis: 5Ta caused a significant reduction in APTT compared to ‘no treatment’, 1Ta and 10Ta and a significant reduction in PT compared to 0Ta. Therefore, we conclude that 5mol% of Ta optimised the hemostatic properties of these mesoporous bioactive glasses.

Intrinsic pathway of blood coagulation contributes to thrombogenicity of atherosclerotic plaque

Blood ◽  
2002 ◽  
Vol 99 (12) ◽  
pp. 4475-4485 ◽  
Author(s):  
Natalya M. Ananyeva ◽  
Diana V. Kouiavskaia ◽  
Midori Shima ◽  
Evgueni L. Saenko
Keyword(s):  
Blood Coagulation ◽  
Thrombus Formation ◽  
Intrinsic Factor ◽  
Density Lipoprotein ◽  
Fold Increase ◽  
Intrinsic Pathway ◽  
Extrinsic Pathway ◽  
Thrombin Formation

Thrombosis is the major mechanism underlying acute complications of atherosclerosis. Although thrombogenicity of atherosclerotic plaques has been ascribed to activation of the extrinsic pathway of blood coagulation, in the present study we investigated contribution of the intrinsic factor VIII (fVIII)–dependent pathway. We found that in vitro exposure of human macrophages and smooth muscle cells (SMCs) to atherogenic oxidized low-density lipoprotein (oxLDL) enhances their ability to support activity of 2 major complexes of the intrinsic pathway, Xase and prothrombinase, leading to a 20- and 10-fold increase in thrombin formation, respectively. In contrast, human aortic endothelial cells were less responsive to oxLDL. The increase in the intrinsic procoagulant activity was related to formation of additional fVIII binding sites due to enhanced translocation of phosphatidylserine to the outer surface of oxLDL-treated cells and a 5-fold higher affinity of interaction between components of the Xase complex, activated factors VIII and IX. Processes occurring at early apoptotic stages, including changes in the cell membrane induced by free radicals, may be related to activation of the intrinsic pathway as suggested by effects of inhibitors of early apoptosis on thrombin formation. Immunohistochemical studies on human atherectomy specimens revealed the presence of fVIII in the vicinity of macrophages and SMCs in atheromatous regions with massive deposits of oxLDL, supporting the possible involvement of the intrinsic pathway in thrombus formation in vivo. Our data predict that the intrinsic pathway significantly enhances thrombogenicity of atherosclerotic lesions after removal of the endothelial layer and exposure of SMCs and macrophages to blood flow.

scholarly journals In Vitro and Ex Vivo Evaluation of Nepafenac-Based Cyclodextrin Microparticles for Treatment of Eye Inflammation

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 709 ◽  
Author(s):  
Blanca Lorenzo-Veiga ◽  
Patricia Diaz-Rodriguez ◽  
Carmen Alvarez-Lorenzo ◽  
Thorsteinn Loftsson ◽  
Hakon Hrafn Sigurdsson
Keyword(s):  
Zeta Potential ◽  
Physicochemical Properties ◽  
Inflammatory Mediators ◽  
Ex Vivo ◽  
Posterior Segment ◽  
Inflammatory Activity ◽  
Commercial Formulation ◽  
Anti Inflammatory ◽  
Negative Zeta Potential

The aim of this study was to design and evaluate novel cyclodextrin (CD)-based aggregate formulations to efficiently deliver nepafenac topically to the eye structure, to treat inflammation and increase nepafenac levels in the posterior segment, thus attenuating the response of inflammatory mediators. The physicochemical properties of nine aggregate formulations containing nepafenac/γ-CD/hydroxypropyl-β (HPβ)-CD complexes as well as their rheological properties, mucoadhesion, ocular irritancy, corneal and scleral permeability, and anti-inflammatory activity were investigated in detail. The results were compared with a commercially available nepafenac suspension, Nevanac® 3 mg/mL. All formulations showed microparticles, neutral pH, and negative zeta potential (–6 to –27 mV). They were non-irritating and nontoxic and showed high permeation through bovine sclera. Formulations containing carboxymethyl cellulose (CMC) showed greater anti-inflammatory activity, even higher than the commercial formulation, Nevanac® 0.3%. The optimized formulations represent an opportunity for topical instillation of drugs to the posterior segment of the eye.

Coagulation assessment by rotation thrombelastometry in normal pregnancy

2009 ◽  
Vol 101 (04) ◽  
pp. 755-761 ◽  
Author(s):  
Nicolas Carrabin ◽  
Mehdi Benchaib ◽  
Oriane Fontaine ◽  
Albrice Levrat ◽  
Denis Massignon ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Point Of Care ◽  
Normal Pregnancy ◽  
Clot Lysis ◽  
Clotting Time ◽  
Intrinsic Pathway ◽  
Extrinsic Pathway ◽  
Coagulation Tests ◽  
Maximum Clot Firmness

SummaryWe analysed changes in coagulation during normal pregnancy with a novel point-of-care device based on thrombelastometry (ROTEM®). We compared the results obtained with those of standard coagulation tests in 104 patients: 20 non-pregnant women (controls) and 84 women in the first (T1, n=17), second (T2, n=9) and third (T3, n=58) trimesters of pregnancy. We measured the clotting time (CT), the maximum clot firmness (MCF), the early clot amplitude at 5 and 15 minutes (CA5, CA15) and the clot lysis index (CLI30) with four tests containing specific reagents. (a) The INTEM® test involving ellagic acid activated the intrinsic pathway and (b) the EXTEM® test using tissue factor triggered the extrinsic pathway; (c) The FIBTEM® test based on a platelet inhibitor (cytochalasin D) evaluated the contribution of fibrinogen to clot formation and (d) the APTEM® test was similar to the EXTEM but was based on inhibition in vitro of fibrinolysis by aprotinin. CT and CLI30 were not significantly modified during pregnancy whereas MCF, CA5 and CA15 (INTEM, EXTEM, FIBTEM) increased significantly between the second and third trimesters (e.g. median [interquartile range]: MCF-FIBTEM, 13 [11–16] mm vs. 19 [17–23] mm, respectively, in controls and T3, p< 0.001). EXTEM values were not significantly different from those measured with APTEM. There were significant correlations between the results obtained with ROTEM and those from standard coagulation tests. ROTEM analysis showed a marked increase in coagulability during normal pregnancy. ROTEM values may serve as the basis for future studies in pregnant women.

Effect of bile components on the surface properties of bifidobacteria

2002 ◽  
Vol 69 (2) ◽  
pp. 293-302 ◽  
Author(s):  
GUILLERMO KOCIUBINSKI ◽  
ANDREA GÓMEZ ZAVAGLIA ◽  
PABLO F. PÉREZ ◽  
EDGARDO A. DISALVO ◽  
GRACIELA L. DE ANTONI
Keyword(s):  
Zeta Potential ◽  
Surface Properties ◽  
Highly Hydrophobic ◽  
Negative Zeta Potential

The action of bile on bifidobacteria was studied by measuring changes in zeta potential, hydrophobicity and adherence to enterocyte-like cells in vitro. Highly hydrophobic strains shocked with bile displayed more negative zeta potential values and a decrease in adherence. When a non-hydrophobic non-adherent strain (CIDCA 5324) was shocked with bile, an increase in hydrophobicity was observed. However, no changes of zeta potential or adherence properties were apparent. The action of the bile components was different from the action of whole bile. Cholate and deoxycholate produced a decrease in the negativity of zeta potential values of all strains studied whereas taurocholate displayed a shift in zeta potential of hydrophobic strains to more negative values, thus explaining the decrease in the autoaggregation by charge repulsion. However, the decrease in zeta potential caused by cholate and deoxycholate did not increase autoaggregation in a hydrophobic non-adherent strain (CIDCA 531). This suggests that other forces are contributing to autoaggregation.

Sodium pentosan polysulphate as a polyanionic inhibitor of calcium oxalate crystallization in vitro and in vivo

1985 ◽  
Vol 68 (3) ◽  
pp. 369-371 ◽  
Author(s):  
R. W. Norman ◽  
D. S. Scurr ◽  
W. G. Robertson ◽  
M. Peacock
Keyword(s):  
Zeta Potential ◽  
Calcium Oxalate ◽  
Human Subjects ◽  
Stone Disease ◽  
Active Inhibitor ◽  
Novel Approach ◽  
Pentosan Polysulphate ◽  
Negative Zeta Potential

1. Studies in vitro showed that sodium pentosan polysulphate (SPP) is an active inhibitor of calcium oxalate crystal growth and agglomeration and that it acts by increasing the negative zeta potential on the surface of calcium oxalate crystals. 2. Oral administration to human subjects resulted in an increase in the negative zeta potential, which is consistent with an increase in the polyanionic inhibitory activity of urine. SPP may offer a novel approach to the medical management of recurrent calcium oxalate stone disease.

scholarly journals Composition-dependent in vitro apatite formation at mesoporous bioactive glass-surfaces quantified by solid-state NMR and powder XRD

RSC Advances ◽  
2015 ◽  
Vol 5 (105) ◽  
pp. 86061-86071 ◽  
Author(s):  
Claudia Turdean-Ionescu ◽  
Baltzar Stevensson ◽  
Jekabs Grins ◽  
Isabel Izquierdo-Barba ◽  
Ana García ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Powder Xrd ◽  
Apatite Formation ◽  
Carbonate Apatite ◽  
Bioactive Glasses ◽  
Glass Surfaces ◽  
Mesoporous Bioactive Glass ◽  
Hydroxy Carbonate

Solid-state NMR and powder XRD are employed to quantify the ACP (amorphous calcium phosphate) and HCA (hydroxy-carbonate apatite) components grown from three mesoporous bioactive glasses with variable compositions.

scholarly journals What We Know About Kininogen Structure – Importance for Function and Perspectives from Cryo-EM

2021 ◽  
Author(s):  
Michal Błażej Ponczek
Keyword(s):  
Spatial Structure ◽  
Blood Coagulation ◽  
Atomic Level ◽  
Coagulation Cascade ◽  
Intrinsic Pathway ◽  
Extrinsic Pathway ◽  
Kinin System ◽  
Pathway Activation ◽  
Kallikrein Kinin System ◽  
Treatment Application

Kininogens are multidomain glycoproteins found in the blood of most vertebrates. They are important in the blood coagulation cascade pathways - in intrinsic pathway activation leading to thrombin generation partially independently from tissue factor dependent extrinsic pathway, connecting blood coagulation with the kallikrein-kinin system. Nothing is known about the shape on atomic level therefore the endeavor to obtain the good-quality spatial structure of kininogens is important for a better understanding of their role in disease and treatment. Application of cryo-EM is important for solving the spatial structure of kininogens, drawing new frontiers in understanding the function and opening new pathways for drug development.

scholarly journals Integration of Mesoporous Bioactive Glass Nanoparticles and Curcumin into PHBV Microspheres as Biocompatible Composite for Drug Delivery Applications

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3177
Author(s):  
Arturo E. Aguilar-Rabiela ◽  
Aldo Leal-Egaña ◽  
Qaisar Nawaz ◽  
Aldo R. Boccaccini
Keyword(s):  
Drug Delivery ◽  
Bioactive Glass ◽  
Biomedical Applications ◽  
Drug Carriers ◽  
Bioactive Glasses ◽  
Composite Microspheres ◽  
Convenient Approach ◽  
Model Drug ◽  
Mesoporous Bioactive Glass

Bioactive glasses (BGs) are being increasingly considered for biomedical applications. One convenient approach to utilize BGs in tissue engineering and drug delivery involves their combination with organic biomaterials in order to form composites with enhanced biocompatibility and biodegradability. In this work, mesoporous bioactive glass nanoparticles (MBGN) have been merged with polyhydroxyalkanoate microspheres with the purpose to develop drug carriers. The composite carriers (microspheres) were loaded with curcumin as a model drug. The toxicity and delivery rate of composite microspheres were tested in vitro, reaching a curcumin loading efficiency of over 90% and an improving of biocompatibility of different concentrations of MBGN due to its administrations through the composite. The composite microspheres were tested in terms of controlled release, biocompatibility and bioactivity. Our results demonstrate that the composite microspheres can be potentially used in biomedicine due to their dual effects: bioactivity (due to the presence of MBGN) and curcumin release capability.

Bio-Hybrid Composite Scaffold from Silk Fibroin/Chitosan/Mesoporous Bioactive Glass Microspheres for Tissue Engineering Applications

2015 ◽  
Vol 1131 ◽  
pp. 79-83 ◽  
Author(s):  
Ratiya Phetnin ◽  
Sirirat Tubsungnoen Rattanachan
Keyword(s):  
Tissue Engineering ◽  
Bioactive Glass ◽  
Silk Fibroin ◽  
Hybrid Composite ◽  
Composite Scaffold ◽  
Composite Scaffolds ◽  
Bioactive Glasses ◽  
Engineering Applications ◽  
Mesoporous Bioactive Glass

This research aims to fabricate the novel bio-hybrid composite scaffold from mesoporous bioactive glasses/silk fibroin/chitosan (MBGs/SF/CS) for use in tissue engineering applications. MBGs/SF/CS composite scaffolds were successfully fabricated using freezing and lyophilization process. Two types of mesoporous bioactive glasses which were irregular and spherical shape were dispersed in the silk fibroin/chitosan based scaffolds in order to improve the mechanical strength and bioactivity. SEM observation showed the interconnected pores with pore size from 100 to 300 µm. XRD and FTIR exhibited the present of silk fibroin, chitosan, and MBGs in composite scaffolds. The incorporation of MBGs in SF/CS scaffolds significantly increased the compressive strength of scaffolds. The composite scaffolds were immersed in the simulated body fluid (SBF) for in vitro bioactivity test. The in vitro bioactivity results indicated that the MBGs/SF/CS induced hydroxycarbonate apatite (HCA) formation while there was no change for SF/CS scaffolds. Furthermore, mesoporous bioactive glass with micro-spherical particles (MBGMs) which easily dispersed in SF/CS solution during the fabrication of scaffolds as compared to mesoporous bioactive glass with irregular shape (MBGs). The results showed that MBGs/SF/CS composite scaffolds could be useful composite scaffolds for tissue engineering applications.

scholarly journals What We Know About Kininogen Structure – Importance for Function and Perspectives from Cryo-EM

2021 ◽  
Author(s):  
Michal Błażej Ponczek
Keyword(s):  
Spatial Structure ◽  
Blood Coagulation ◽  
Atomic Level ◽  
Coagulation Cascade ◽  
Intrinsic Pathway ◽  
Extrinsic Pathway ◽  
Kinin System ◽  
Pathway Activation ◽  
Kallikrein Kinin System ◽  
Treatment Application

Kininogens are multidomain glycoproteins found in the blood of most vertebrates. They are important in the blood coagulation cascade pathways - in intrinsic pathway activation leading to thrombin generation partially independently from tissue factor dependent extrinsic pathway, connecting blood coagulation with the kallikrein-kinin system. Nothing is known about the shape on atomic level therefore the endeavor to obtain the good-quality spatial structure of kininogens is important for a better understanding of their role in disease and treatment. Application of cryo-EM is important for solving the spatial structure of kininogens, drawing new frontiers in understanding the function and opening new pathways for drug development.

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