In Vitro Design Investigation of a Rotating Helical Magnetic Swimmer for Combined 3-D Navigation and Blood Clot Removal

BackgroundUntreated ischemic stroke can lead to severe morbidity and death, and as such, there are numerous endovascular blood-clot removal (thrombectomy) devices approved for human use. Human thrombi types are highly variable and are typically classified in qualitative terms – ‘soft/red,’ ‘hard/white,’ or ‘aged/calcified.’ Quantifying human thrombus properties can accelerate the development of thrombus analogs for the study of thrombectomy outcomes, which are often inconsistent among treated patients.Methods‘Soft’human thrombi were created from blood samples ex vivo (ie, human blood clotted in sample vials) and tested for mechanical properties using a hybrid rheometer material testing system. Synthetic thrombus materials were also mechanically tested and compared with the ‘soft’ human blood clots.ResultsMechanical testing quantified the shear modulus and dynamic (elastic) modulus of volunteer human thrombus samples. This data was used to formulate a synthetic blood clot made from a composite polymer hydrogel of polyacrylamide and alginate (PAAM-Alg). The PAAM-Alg interpenetrating network of covalently and ionically cross-linked polymers had tunable elastic and shear moduli properties and shape memory characteristics.ConclusionsDue to its adjustable properties, PAAM-Alg can be modified to mimic various thrombi classifications. Future studies will include obtaining and quantitatively classifying patient thrombectomy samples and altering the PAAM-Alg to mimic the results for use with in vitro thrombectomy studies.

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A Monoclonal Antibody-Based Enzyme Immunoassay for Fibrin Degradation Products in Plasma

Thrombosis and Haemostasis ◽

10.1055/s-0038-1642777 ◽

1988 ◽

Vol 59 (02) ◽

pp. 310-315 ◽

Cited By ~ 64

Author(s):

P W Koppert ◽

E Hoegee-de Nobel ◽

W Nieuwenhuizen

Keyword(s):

Enzyme Immunoassay ◽

Degradation Products ◽

Blood Clot ◽

Tissue Type ◽

Fibrin Degradation Products ◽

Type Plasminogen Activator ◽

Strong Positive Reaction ◽

Sandwich Type ◽

Capture Antibody

SummaryWe have developed a sandwich-type enzyme immunoassay (EIA) for the quantitation of fibrin degradation products (FbDP) in plasma with a time-to-result of only 45 minutes.* The assay is based on the combination of the specificities of two monoclonal antibodies (FDP-14 and DD-13), developed in our institute. FDP-14, the capture antibody, binds both fibrinogen degradation products (FbgDP) and FbDP, but does not react with the parent fibrin(ogen) molecules. It has its epitope in the E-domain of the fibrinogen molecule on the Bβ-chain between amino acids 54-118. Antibody DD-13 was raised using D-dimer as antigen and is used as a tagging antibody, conjugated with horse-radish peroxidase. A strong positive reaction is obtained with a whole blood clot lysate (lysis induced by tissue-type plasminogen activator) which is used as a standard. The EIA does virtually not detect FbgDP i. e. purified fragments X, Y, or FbgDP generated in vitro in plasma by streptokinase treatment. This indicates that the assay is specific for fibrin degradation products.We have successfully applied this assay to the plasma of patients with a variety of diseased states. In combination with the assay previously developed by us for FbgDP and for the total amount of FbgDP + FbDP (TDP) in plasma, we are now able to study the composition of TDP in patients plasma in terms of FbgDP and FbDP.

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Dependence of Blood Clot Lysis on the Mode of Transport of Urokinase into the Clot - A Magnetic Resonance Imaging Study in Vitro

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648188 ◽

1991 ◽

Vol 65 (05) ◽

pp. 549-552 ◽

Cited By ~ 55

Author(s):

A Blinc ◽

G Planinšič ◽

D Keber ◽

O Jarh ◽

G Lahajnar ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Pressure Difference ◽

Volume Flow Rate ◽

Blood Clot ◽

Linear Regression Analysis ◽

Imaging Study ◽

Clot Lysis ◽

Resonance Imaging

SummaryMagnetic resonance imaging was employed to study the dependence of clot lysing patterns on two different modes of transport of urokinase into whole blood clots. In one group of clots (nonperfused clots, n1 = 10), access of urokinase to the fibrin network was possible by diffusion only, whereas in the other group (perfused clots, n2 = 10) bulk flow of plasma containing urokinase was instituted through occlusive clots by a pressure difference of 3 .7 kPa (37 cm H2O) across 3 cm long clots with a diameter of 4 mm. It was determined separately that this pressure difference resulted in a volume flow rate of 5.05 ± 2.4 × 10−2 ml/min through occlusive clots. Perfused clots diminished in size significantly in comparison to nonperfused ones already after 20 min (p <0.005). Linear regression analysis of two-dimensional clot sizes measured by MRI showed that the rate of lysis was more than 50-times faster in the perfused group in comparison to the nonperfused group. It was concluded that penetration of the thrombolytic agent into clots by perfusion is much more effective than by diffusion. Our results might have some implications for understanding the differences in lysis of arterial and venous thrombi.

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Urokinase Evaluated with the Experimental Radioactive Embolus

Thrombosis and Haemostasis ◽

10.1055/s-0038-1654164 ◽

1967 ◽

Vol 17 (03/04) ◽

pp. 405-411

Author(s):

M Hume

Keyword(s):

Animal Experiment ◽

Blood Clot ◽

In Vitro Testing ◽

Effective Agent

SummaryUrokinase and urokinase-activated plasmin have been given to the dog and rabbit. A thrombolytic state has been induced. Purified urokinase has induced lysis of the experimental radioactive blood clot embolus in the circulation. Demonstration of effectiveness in this animal experiment is hampered by inhibition of the agents in the circulation to a degree much greater than was noted in previous experiments with streptokinase. In vitro testing indicates that under proper conditions urokinase will be an effective agent in the treatment of human thromboembolism.

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Hemostatic wound dressings: Predicting their effects by in vitro tests

Journal of Biomaterials Applications ◽

10.1177/0885328219831095 ◽

2019 ◽

Vol 33 (9) ◽

pp. 1285-1297 ◽

Cited By ~ 2

Author(s):

Cornelia Wiegand ◽

Martin Abel ◽

Uta-Christina Hipler ◽

Peter Elsner ◽

Michael Zieger ◽

...

Keyword(s):

Blood Clot ◽

Wound Dressings ◽

In Vitro Tests ◽

Regenerated Cellulose ◽

Oxidized Regenerated Cellulose ◽

Inflammatory Reactions ◽

In Vitro Techniques ◽

Cotton Gauze

Background Application of controlled in vitro techniques can be used as a screening tool for the development of new hemostatic agents allowing quantitative assessment of overall hemostatic potential. Materials and methods Several tests were selected to evaluate the efficacy of cotton gauze, collagen, and oxidized regenerated cellulose for enhancing blood clotting, coagulation, and platelet activation. Results Visual inspection of dressings after blood contact proved the formation of blood clots. Scanning electron microscopy demonstrated the adsorption of blood cells and plasma proteins. Significantly enhanced blood clot formation was observed for collagen together with β-thromboglobulin increase and platelet count reduction. Oxidized regenerated cellulose demonstrated slower clotting rates not yielding any thrombin generation; yet, led to significantly increased thrombin-anti-thrombin-III complex levels compared to the other dressings. As hemostyptica ought to function without triggering any adverse events, induction of hemolysis, instigation of inflammatory reactions, and initiation of the innate complement system were also tested. Here, cotton gauze provoked high PMN elastase and elevated SC5b-9 concentrations. Conclusions A range of tests for desired and undesired effects of materials need to be combined to gain some degree of predictability of the in vivo situation. Collagen-based dressings demonstrated the highest hemostyptic properties with lowest adverse reactions whereas gauze did not induce high coagulation activation but rather activated leukocytes and complement.

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The Haemocompatibility of Biomaterials In Vitro: Investigations on the Mechanism of the Whole-blood Clot Formation Test

Alternatives to Laboratory Animals ◽

10.1177/026119299202000305 ◽

1992 ◽

Vol 20 (3) ◽

pp. 390-395 ◽

Cited By ~ 1

Author(s):

Thomas Groth ◽

Katrin Derdau ◽

Frank Strietzel ◽

Frank Foerster ◽

Hartmut Wolf

Keyword(s):

Whole Blood ◽

Blood Clotting ◽

Blood Clot ◽

Formation Rate ◽

Clot Formation ◽

Coagulation Cascade ◽

Contact Activation ◽

Human Fibrinogen ◽

Static Conditions

Twenty years ago Imai & Nose introduced a whole-blood clotting test for the estimation of haemocompatibility of biomaterials in vitro In our paper a modification of this assay is described and the mechanism of clot formation further elucidated. It was found that neither the inhibition of platelet function nor the removal of platelets from blood significantly changed the clot formation rate on glass and polyvinyl chloride in comparison to the rate tor whole blood. Scanning electron microscopy demonstrated that platelets were not involved in clot formation near the blood/biomaterial interface. Thus, it was concluded that the system of contact activation of the coagulation cascade dominates during clot formation under static conditions. The latter conclusion was supported by the fact that preadsorption of human serum albumin or human fibrinogen onto the glass plates used, decreased the clot formation rate in the same manner.

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In Vitro Assessment of Antioxidant, Thrombolytic, Antimicrobial Activities of Medicinal Plant Pandanus odoratissimus L. Leaves Extract

Journal of Scientific Research ◽

10.3329/jsr.v12i3.44225 ◽

2020 ◽

Vol 12 (3) ◽

pp. 379-390

Author(s):

F. I. Penu ◽

S. M. Ivy ◽

F. Ahmed ◽

J. Uddin ◽

M. S. Hossain ◽

...

Keyword(s):

Soluble Fraction ◽

Blood Clot ◽

Folk Medicine ◽

Maximum Level ◽

Antimicrobial Activities ◽

Total Phenolic ◽

Thrombolytic Activity ◽

Standard Drug ◽

Pandanus Odoratissimus

The present study was carried out to investigate phytochemical, antioxidant; antimicrobial, thrombolytic activity and estimate total phenolic, total flavonoid content of Pandanus odoratissimus (p.odoratissimus) leaves of methanol extract. In thrombolytic activity, aqueous soluble fraction (AQSF) exhibited highest percentage (46.58 %) of potential to lyse blood clot compared to standard drug streptokinase (69.52 %). In antimicrobial assay, dichloromethane soluble fraction (DCMSF) explored the highest diameter of clear zone of inhibition against both gram positive (19.60 ± 0.12 mm) and gram negative (20.00 ± 0.20 mm) bacteria compared to standard antibiotic, Kanamycin (50.00 ± 0.19). Levels of antioxidant were determined by DPPH assay followed by calculated IC50 values of different Kupchan extracts. The methyl soluble fraction (MSF) showed the lowest level of IC50 value (36.70 ± 0.32 µg/mL) in comparison to ascorbic acid (12.48 ± 0.09 µg/mL) while MSF disclosed the maximum level (62.19 ± 0.26 mg of GAE/g of extract) of total phenolic content in the extracts of P. odoratissimus. This study was conducted to validate the P. odoratissimus leaves used as a folk medicine such as, antioxidant, thrombolytic, and antimicrobial potential.

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What is the clinical applicability of regenerative therapies in dentistry?

RGO - Revista Gaúcha de Odontologia ◽

10.1590/1981-863720170002000113112 ◽

2017 ◽

Vol 65 (4) ◽

pp. 359-367 ◽

Cited By ~ 1

Author(s):

Giulia Tarquinio DEMARCO ◽

Laura Borges KIRSCHNICK ◽

Luis Bayardo WATSON ◽

Marcus Cristian MUNIZ CONDE ◽

Flávio Fernando DEMARCO ◽

...

Keyword(s):

Stem Cells ◽

Dental Pulp ◽

Platelet Rich Plasma ◽

Blood Clot ◽

Collagen Scaffold ◽

Bone Tissue Regeneration ◽

Promising Alternative ◽

Organ Regeneration ◽

Regenerative Therapies

ABSTRACT Regenerative therapies have been widely developed in dentistry and it is important to incorporate dentists’ knowledge of these new therapies into the dental clinic routine. This study reviewed the literature on regenerative therapies and clinical applications. Tissue engineering has contributed to changes in the paradigm of restorative health sciences. Its pillars underpin the techniques of tissue and organ regeneration. Despite the majority of studies in this field being in vitro, a range of preclinical studies and methodologies has been formed using these principles and they are already being used on humans. The use of platelet-rich plasma and platelet-rich fibrin in surgery as natural scaffolds for the reestablishment of bone and periodontal tissue are often reported in the literature and clinical trials using this approach have shown promising results. Stem cells from autologous dental pulp have been successfully applied in bone tissue regeneration using natural collagen scaffold in humans. In addition, revascularization of the root canal already appears in the literature as a promising alternative to apexification. The principle behind this therapy is the use of the blood clot as a scaffold and the migration of stem cells of the apical papilla to regenerate the dental pulp organ. Final considerations: Although still in the early stages, regenerative therapies can now be used in dental practice. Knowledge of the principles governing these therapies should be understood by the dentist for use in clinical practice.

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Effect of Heparin on TAFI-Dependent Inhibition of Fibrinolysis: Relative Importance of TAFIa Generated by Clot-Bound and Fluid Phase Thrombin

Thrombosis and Haemostasis ◽

10.1055/s-0037-1613199 ◽

2002 ◽

Vol 88 (08) ◽

pp. 282-287 ◽

Cited By ~ 14

Author(s):

Anna Pentimone ◽

Bianca Binetti ◽

Marialisa Cramarossa ◽

Donatella Piro ◽

Nicola Semeraro ◽

...

Keyword(s):

Thrombin Generation ◽

Blood Clot ◽

Fluid Phase ◽

Clot Lysis ◽

Relative Importance ◽

Thrombin Activatable Fibrinolysis Inhibitor ◽

Dependent Inhibition ◽

Fibrinolysis Inhibitor ◽

Dependent Mechanism

SummaryHeparin has been proposed to enhance thrombolysis by inhibiting thrombin-dependent generation of activated TAFI (thrombin activatable fibrinolysis inhibitor), a carboxypeptidase that inhibits fibrinolysis. We evaluated the effect of heparin in an in vitro thrombolysis model consisting of a radiolabelled blood clot submerged in defibrinated plasma. Fibrinolysis was induced by adding t-PA (250 ng/ml) and calcium to the plasma bath. Control experiments indicated that thrombin generation induced by recalcification caused significant TAFI activation and inhibited clot lysis. Heparin (up to 1 U/ml), added to the plasma bath, failed to enhance clot lysis. Thrombin generation in the fluid phase was totally inhibited by heparin at concentrations > 0.5 U/ml. In contrast, thrombin generation on the clot surface was not inhibited by heparin (1 U/ml). TAFIa generation did occur in heparin-containing samples (1 U/ml) and amounted to about 10% of TAFIa formed in control samples. This low amount of TAFIa did exert antifibrinolytic activity as indicated by the observation that the addition of a specific TAFIa inhibitor (PTI) along with heparin enhanced clot lysis. Hirudin (10 µg/ml), at variance with heparin, inhibited clot-bound thrombin and enhanced clot lysis. These data show that heparin is unable to stimulate fibrinolysis through a TAFI-dependent mechanism, most likely because of its inefficiency in inhibiting thrombin generation on the clot surface. Moreover, they suggest that clot-bound thrombin plays a major role in TAFI-mediated inhibition of fibrinolysis through “localized” TAFIa generation.

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TITANIUM NANOPARTICLES CONJUGATED WITH STREPTOKINASE AS A MODIFIED THROMBOLYTIC AGENT

International Journal of Current Pharmaceutical Research ◽

10.22159/ijcpr.2020v12i1.36824 ◽

2020 ◽

pp. 18-25

Author(s):

HAYDER H. ABED ◽

ESTABRAQ AR. ALWASITI ◽

AMIR T. TAWFEEQ

Keyword(s):

Thrombolytic Agent ◽

Blood Clot ◽

Control Group ◽

Thrombolytic Activity ◽

Protein Assay ◽

Blood Clots ◽

Ft Ir ◽

Titanium Nanoparticles ◽

D Dimer

Objective: Blood clots are the main cause of death worldwide by stroke and myocardial infarction. Streptokinase a thrombolytic agent that is used in the treatment of circulatory disorders. Methods: Titanium Nanoparticles was supplied from Changsha Santech Co. Its characterized were studied using (FT-IR, XRD, AFM, FE-SEM). Streptokinase at concentration 0.1 mg/ml was conjugated with Titanium nanoparticles using PH equal to 5.2 with continuous stirring. Formation of Streptokinase loading Titanium nanoparticles confirmed using FT-IR, Ninhydrine’s test and Bradford protein assay. Physicochemical Properties were studied in vitro. Thrombolytic activity in vitro was determined using d–dimer indicator and weight of blood clot after treatment as indicators of thrombolytic activity. Results: Titanium nanoparticles show particle size at range 31 nm. The thrombolytic activity of streptokinase loading Titanium nanoparticles shows significant value in d-dimer and weight of blood clot compared with the control group and non-significant compared with an equivalent amount of streptokinase alone. Conclusion: Titanium nanoparticles conjugated with streptokinase show high thrombolytic activity against blood clots in vitro.

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