STUDIES ON ELECTRICALLY INDUCED THROMBOSIS AND RELATED PHENOMENA

1966 ◽  
Vol 44 (6) ◽  
pp. 881-886 ◽  
Author(s):  
C. R. Cowan ◽  
Frank C. Monkhouse
Keyword(s):  
Thrombus Formation ◽  
Electrical Current ◽  
Platinum Electrodes ◽  
Metal Electrodes ◽  
Ph Changes ◽  
Gas Formation ◽  
Negative Pole ◽  
Mesenteric Vessels ◽  
Saline Solutions

Microampere currents applied with metal electrodes to the mesenteric vessels of mice caused thrombosis, accompanied by electrolyte dissociation and gas formation. When the products of dissociation were removed, clumping, constriction, or thrombosis did not occur. When glass–starch electrodes were used, currents up to 200 μA, applied for 30 minutes, were without effect. Changing to platinum electrodes and applying 50-μA currents caused, in less than 30 seconds, constriction at the negative pole, clumping, and thrombosis, without constriction at the positive pole. Measurements showed an increase in pH at the negative pole and a decrease at the positive pole. When saline solutions with increased or decreased pH were applied to the vessels, constriction and thrombus formation occurred similar to those produced by electrical current. Experiments were done on heparinized blood in vitro with a U-tube designed to contain the products of electrolysis at each pole. With platinum electrodes a coagulum formed at the positive pole and pH changes occurred at both poles. With glass–starch electrodes these changes did not occur.

scholarly journals Morphologic Platelet Changes During Thrombus Formation in the Rat

1977 ◽  
Author(s):  
R. Wiedemann ◽  
W. Weichert ◽  
K. Breddin
Keyword(s):  
Vessel Wall ◽  
Thrombus Formation ◽  
Vascular Lesions ◽  
Mesenteric Vessels ◽  
Platelet Thrombus ◽  
Adhesion Of Platelets ◽  
Damaged Vessel ◽  
Morphologic Changes

The film presents observations in small mesenteric vessels (diameter 10-20 μm) of the rat using high power Nomarski optics. Under stasis conditions platelets appear as flat discs. Leucocytes are often seen creeping slowly along the intact vessel wall. Vascular lesions are produced with a focused laser beam (Hadron 513 biolaser). Immediately after the lesion platelets stick to the site of the microburn either in their native disc like shape without apparent morphologic changes or with protrusions. Within seconds these platelets swell and form protrusions. After 3-10 min, depending on the size of the lesion the vessel is occluded by a platelet thrombus. Platelets undergo further swelling. Later the thrombus is partially or completely swept away and the vessel is recanal i zed. Irreversible fusion of platelets is rarely observed. . New, usually smaller thrombi form at the damaged vessel wall. The morphologic platelet changes observed differ markedly from the changes observed during aggregation in vitro. After injection of a new antithrombotic substance (Bay G 7565) the adhesion of platelets to the damaged area is remarkably diminished. The few platelets which adhere to the site of injury show the same swelling and transformation like in untreated animals. The film demonstrates that it is possible to investigate morphologic changes of single platelets during thrombus formation. It seems possible to adapt this model for the in vivo study of antithrombotic drugs.

scholarly journals Morphologic Platelet Changes in Vitro and During Thrombus Formation in the Rat

1977 ◽  
Author(s):  
R. Wiedemann ◽  
K. Breddin ◽  
H. Grun ◽  
W. Weichert
Keyword(s):  
Incubation Temperature ◽  
Thrombus Formation ◽  
Shape Change ◽  
Vascular Lesions ◽  
Platelet Adhesiveness ◽  
Platelet Morphology ◽  
Mesenteric Vessels ◽  
Adhesion Of Platelets ◽  
Spherical Transformation

Using high power Nomarski optics the shape change of thrombocytes can be shown. Platelets appear in their native shape as flat discs, less than 25% show pseudopodes. Depending on the time after blood sampling and on incubation temperature platelets in PRP or citrated blood swell and form tentacles. The addition of ADP to PRP induces the formation of aggregates. Single platelets form large vesicles rupturing and releasing granulated material. The remaining platelet material fuses. Bencyclan affects platelet morphology by inducing a spherical transformation, which is paralleled by the inhibition of platelet adhesiveness, spreading and aggregation. Observations in small mesenteric vessels of the rat show platelets in their native shape under stasis conditions. Vascular lesions are produced with a focused laserbeam (Hadron 513 biolaser). Immediately after the lesion platelets stick to the site of the microburn. Within seconds these platelets swell and form protrusions. After 3 - 10 min the vessel is occluded by a thrombus, of platelets, which undergo further swelling. Later the thrombus is partially or completely swept away and the vessel is recanalized. Irreversible fusion of platelets is rarely observed. These morphologic platelet changes differ markedly from those observed during in vitro aggregation. Injection of a new antithrombotic substance (Bay G 6575) diminishes the adhesion of platelets on the vessel lesion. The morphologic changes of single platelets (primary shape change) probably represent basic processes in hemostasis and thrombus formation.

scholarly journals Antibiofilm Activity of Electrical Current in a Catheter Model

2015 ◽  
Vol 60 (3) ◽  
pp. 1476-1480 ◽  
Author(s):  
Paul Voegele ◽  
Jon Badiola ◽  
Suzannah M. Schmidt-Malan ◽  
Melissa J. Karau ◽  
Kerryl E. Greenwood-Quaintance ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Bacterial Species ◽  
Electrical Current ◽  
Antibiofilm Activity ◽  
Platinum Electrodes ◽  
Content Type ◽  
Direct Electrical Current ◽  
Viable Bacteria ◽  
Dose Dependent

Catheter-associated infections are difficult to treat with available antimicrobial agents because of their biofilm etiology. We examined the effect of low-amperage direct electrical current (DC) exposure on established bacterial and fungal biofilms in a novel experimentalin vitrocatheter model.Staphylococcus epidermidis,Staphylococcus aureus,Escherichia coli,Pseudomonas aeruginosa, andCandida parapsilosisbiofilms were grown on the inside surfaces of polyvinyl chloride (PVC) catheters, after which 0, 100, 200, or 500 μA of DC was delivered via intraluminally placed platinum electrodes. Catheter biofilms and intraluminal fluid were quantitatively cultured after 24 h and 4 days of DC exposure. Time- and dose-dependent biofilm killing was observed with all amperages and durations of DC administration. Twenty-four hours of 500 μA of DC sterilized the intraluminal fluid for all bacterial species studied; no viable bacteria were detected after treatment ofS. epidermidisandS. aureusbiofilms with 500 μA of DC for 4 days.

Physiological and hypertonic saline solutions impair ciliary activity in vitro

2000 ◽  
Vol 25 (4) ◽  
pp. 331-332
Author(s):  
W.M. Boek ◽  
N. Keles ◽  
K. Graamans ◽  
E.H. Huizing
Keyword(s):  
Hypertonic Saline ◽  
Ciliary Activity ◽  
Saline Solutions

Experimental Studies on a Recombinant Hirudin, CGP 39393

1991 ◽  
Vol 65 (04) ◽  
pp. 355-359 ◽  
Author(s):  
E Gray ◽  
J Watton ◽  
S Cesmeli ◽  
T W Barrowcliffe ◽  
D P Thomas
Keyword(s):  
Thrombin Generation ◽  
Bleeding Time ◽  
Thrombus Formation ◽  
Experimental Studies ◽  
Venous Stasis ◽  
Antithrombotic Agent ◽  
Recombinant Hirudin ◽  
Excessive Bleeding ◽  
Generation Test

SummaryThe in vitro anticoagulant activities of recombinant desulphatohirudin (r-hirudin) were studied in the activated partial thromboplastin time (APTT) and the thrombin generation test : systems. In the APTT at concentrations below 5 μg/ml, r-hirudin showed a dose-response curye. At concentrations above 5 μg/ml, the plasma became unclottable, but in the thrombin generation test , at least 10 μg/ml of r-hirudin was required for full inhibition of thrombin generation. The antithrombotic effect was assessed using a rabbit venous stasis model; 150 μg/ml r-hirudin completely prevented thrombus formation at 10 and 20 min stasis. At antithrombotic dose, the mean bleeding time ratio measured in a rabbit ear template model, was not prolonged over control values. At higher doses, the bleeding time ratios were higher than those observed for the same dosage of heparin. These data indicate that while r-hirudin is an effective antithrombotic agent, antithrombotic doses have to be carefully titrated to avoid excessive bleeding.

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.

The Flowing Clotting Time (Thrombus Formation Time) a Sensitive Test of Hypercoagulability

1969 ◽  
Vol 21 (03) ◽  
pp. 516-523
Author(s):  
H Engelberg ◽  
L. P Engelberg
Keyword(s):  
Thrombus Formation ◽  
Formation Time ◽  
Sensitive Test ◽  
Clotting Time ◽  
Reliable Test ◽  
Time Test ◽  
Plasma Heparin

SummaryThe addition of small amounts of extrinsic thromboplastin or of thrombin to blood in vitro accelerated coagulation more frequently and to a greater extent when determined by the flowing time test than when measured by the silicone clotting time, or by the blood or plasma heparin tolerance tests. Similar results were obtained when intrinsic thromboplastin formation was stimulated by contact with glass. However there was little or no acceleration of the flowing clotting time of plasma obtained from aliquots of the thromboplastin-containing blood. These results indicate that the flowing clotting time (thrombus formation time) of whole blcod is a more reliable test of hypercoagulability than previously described blood or plasma clotting time tests.

Neutralization of a Low Molecular Weight Heparin (LHN-1) and Conventional Heparin by Protamine Sulfate in Rats

1986 ◽  
Vol 56 (03) ◽  
pp. 318-322 ◽  
Author(s):  
V Diness ◽  
P B Østergaard
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Thrombus Formation ◽  
Experimental Models ◽  
Protamine Sulfate ◽  
Low Molecular Weight ◽  
Antithrombotic Effect ◽  
Higher Doses

SummaryThe neutralization of a low molecular weight heparin (LHN-1) and conventional heparin (CH) by protamine sulfate has been studied in vitro and in vivo. In vitro, the APTT activity of CH was completely neutralized in parallel with the anti-Xa activity. The APTT activity of LHN-1 was almost completely neutralized in a way similar to the APTT activity of CH, whereas the anti-Xa activity of LHN-1 was only partially neutralized.In vivo, CH 3 mg/kg and LHN-1 7.2 mg/kg was given intravenously in rats. The APTT and anti-Xa activities, after neutralization by protamine sulfate in vivo, were similar to the results in vitro. In CH treated rats no haemorrhagic effect in the rat tail bleeding test and no antithrombotic effect in the rat stasis model was found at a protamine sulfate to heparin ratio of about 1, which neutralized APTT and anti-Xa activities. In LHN-1 treated rats the haemorrhagic effect was neutralized when APTT was close to normal whereas higher doses of protamine sulfate were required for neutralization of the antithrombotic effect. This probably reflects the fact that in most experimental models higher doses of heparin are needed to induce bleeding than to prevent thrombus formation. Our results demonstrate that even if complete neutralization of APTT and anti-Xa activities were not seen in LHN-1 treated rats, the in vivo effects of LHN-1 could be neutralized as efficiently as those of conventional heparin. The large fall in blood pressure caused by high doses of protamine sulfate alone was prevented by the prior injection of LHN-1.

Surface Modification by Nanobiomaterials for Vascular Tissue Engineering Applications

2020 ◽  
Vol 27 (10) ◽  
pp. 1634-1646 ◽  
Author(s):  
Huey-Shan Hung ◽  
Shan-hui Hsu
Keyword(s):  
Tissue Engineering ◽  
Vascular Tissue ◽  
Thrombus Formation ◽  
Vascular Grafts ◽  
Vascular Tissue Engineering ◽  
Great Success ◽  
Natural Polymers ◽  
Vascular Biomaterials

Treatment of cardiovascular disease has achieved great success using artificial implants, particularly synthetic-polymer made grafts. However, thrombus formation and restenosis are the current clinical problems need to be conquered. New biomaterials, modifying the surface of synthetic vascular grafts, have been created to improve long-term patency for the better hemocompatibility. The vascular biomaterials can be fabricated from synthetic or natural polymers for vascular tissue engineering. Stem cells can be seeded by different techniques into tissue-engineered vascular grafts in vitro and implanted in vivo to repair the vascular tissues. To overcome the thrombogenesis and promote the endothelialization effect, vascular biomaterials employing nanotopography are more bio-mimic to the native tissue made and have been engineered by various approaches such as prepared as a simple surface coating on the vascular biomaterials. It has now become an important and interesting field to find novel approaches to better endothelization of vascular biomaterials. In this article, we focus to review the techniques with better potential improving endothelization and summarize for vascular biomaterial application. This review article will enable the development of biomaterials with a high degree of originality, innovative research on novel techniques for surface fabrication for vascular biomaterials application.

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