scholarly journals The Lysis of Early Fibrin by Eosinophils

1977 ◽  
Author(s):  
Hau C. Kwaan ◽  
Ali A. Hatem
Keyword(s):  
Plasminogen Activator ◽  
Fibrinolytic Activity ◽  
Cell Membranes ◽  
Red Cell ◽  
Platelet Thrombus ◽  
Platelet Aggregates ◽  
Platelet Thrombi ◽  
Arteries And Veins ◽  
Morphologic Changes

This study examins the role of leukocytes within a thrombus by demonstrating the morphologic detail of their activities, the chemotactic properties of thrombi and the presence of plasminogen and possible plasminogen activator within eosinophils. A model which produces discrete, reproducible platelet thrombi in arteries and veins of dogs allowed timed studies of their early evolution. In this model, the growth of the thrombus was constantly monitored by a flowmeter and the thrombus could thus be removed at a selected period in its formation. It was then studied histologically for fibrin activity and also ultrastructually. Little fibrinolytic activity was found. In contrast to neutrophils which are concerned particularly with the phagocytosis and disruption of platelet aggregates, we observed that eosinophils participate in the lysis and disruption of the fibrin within these aggregates. The fibrin is rarely phagocytosed but is acted on at the surfaces of the eosinophils, usually in shallow invaginations of the cell membranes. The fibrin shows morphologic changes of lysis. It appears that eosinophils and neutrophils are concerned with the transformation of the early fibrin and platelet thrombus, rather than with the resolution of the formed, mainly fibrin and red cell thrombus.

The Disappearance of Fibrin from the Pulmonary Vessels in Experimental Fat Embolism

1969 ◽  
Vol 22 (02) ◽  
pp. 360-371 ◽  
Author(s):  
T Saldeen
Keyword(s):  
Plasminogen Activator ◽  
Fibrinolytic Activity ◽  
Early Stage ◽  
Fat Embolism ◽  
Plasminogen Activation ◽  
Activator Concentration ◽  
Embolism Syndrome ◽  
Local Fibrinolysis ◽  
Reticulo Endothelial System

SummaryThe background mechanism for the disappearance of intravascular fibrin from the lungs in connection with pulmonary fat embolism in the rat was studied.The reticulo-endothelial system did not appear to play an important role in the disappearance of fibrin. Premedication of the animals with trypan blue had only slight influence on this disappearance, and the capacity of RES for phagocytizing 131I-denatured albumin was not diminished.Treatment of the rats with a plasminogen activation inhibitor (EACA) resulted in a protracted presence of intravascular fibrin deposits, indicating a role of fibrinolysis in the elimination of the fibrin.In connection with experimental fat embolism induced by fracture, an increase was observed in the plasminogen activator concentration in the blood, but when the fat embolism was induced by intravenous injection of homogenized adipose tissue, this activator decreased. At an early stage following intravascular coagulation in the lungs there was an increased fibrinolytic activity in the lung. These results indicated that the disappearance of fibrin is caused by local fibrinolysis in the lung.Twenty-four hrs after the induction of the fat embolism an increase in the plasminogen activator inhibitors in the blood and a decrease in the fibrinolytic activity in the lung was observed. The significance of this inhibition of the fibrinolytic system for the understanding of the fat embolism syndrome is discussed.

On the Role of the Stable Plasminogen Activator of the Venous Wall in Occlusion Induced Fibrinolytic State

1969 ◽  
Vol 22 (03) ◽  
pp. 544-551 ◽  
Author(s):  
R Constantini ◽  
F Spöttl ◽  
F Holzknecht ◽  
H Braunsteiner
Keyword(s):  
Plasminogen Activator ◽  
Fibrinolytic Activity ◽  
Venous Blood ◽  
Venous Occlusion ◽  
Histochemical Method ◽  
Before And After ◽  
Venous Wall

SummaryThe fibrinolytic activity respectively the PA activity of normal veins before and after venous occlusion is measured by the histochemical method of Todd. The results show marked decreases of PA of the adventitia and an increase of PA of the endothelial type, after venous occlusion. This suggests a transfer of PA through the venous wall into the intravascular lumen, and may be the cause of increased fibrinolytic activity in venous blood after occlusion. Contrary assumptions are discussed.

Fibrinolysis in Grafted Arteries and Veins

1978 ◽  
Vol 40 (02) ◽  
pp. 512-517 ◽  
Author(s):  
Bo Risberg
Keyword(s):  
Plasminogen Activator ◽  
Fibrinolytic Activity ◽  
Vessel Wall ◽  
Observation Time ◽  
Caval Vein ◽  
Vein Grafts ◽  
Aortic Segment ◽  
Plasminogen Activator Activity ◽  
Arteries And Veins

SummaryThe fibrinolytic activity in autologous artery and vein grafts was studied in cats during a 4-month period. The fibrinolytic activity in the wall of an aortic segment interposed in the caval vein was increased in comparison to the normal aorta. In the corresponding segment of the caval vein interposed in the aorta, the fibrinolytic activity was reduced during the observation time. Thrombosed segments had a decreased activity. No changes were seen in sham operated animals. The plasminogen activator activity in the vessel wall was found to be influenced by the surrounding milieu.

scholarly journals Plasminogen activator inhibitor-1 in the evolution of stroke

2004 ◽  
Vol 132 (5-6) ◽  
pp. 143-147 ◽  
Author(s):  
Zagorka Jovanovic ◽  
Mirka Ilic ◽  
Jasna Zidverc-Trajkovic ◽  
Aleksandra Pavlovic ◽  
Milija Mijajlovic ◽  
...  
Keyword(s):  
Acute Stroke ◽  
Plasminogen Activator ◽  
Fibrinolytic Activity ◽  
Plasminogen Activator Inhibitor ◽  
Control Group ◽  
Plasminogen Activator Inhibitor 1 ◽  
Computed Tomography Scanning ◽  
Activator Inhibitor ◽  
Pai 1

Fibrinolytic activity in the acute stroke was examined by monitoring the level of plasminogen activator inhibitor-1 (PAI-1), as one of the indicators of fibrinolytic activity. Given the role of PAI-1 in the processes of atherogenesis and thrombogenesis, plasma PAI-1 level was measured in 59 patients (up to 50 years of age) with atherothrombotic stroke (verified by computed tomography scanning or magnetic resonance imaging of brain) in the period from 12 to 24 hours (I analysis) and 30 days after the onset of stroke (II analysis); then, it was correlated with plasma PAI-1 level in the control group (57 healthy subjects), which was 2.86?0.70 U/ml. It was found that PAI-1 level was significantly higher in the acute stroke (I analysis: PAI-1 =4.10?1.40 U/ml, p<0.001; II analysis: PAI-1 =3.64+0.90 U/ml, p<0.001), while fibrinolytic activity was lower, especially on the first day from the stroke that was not completely increased even after 30 days. There was no difference in PAI-1 levels between the subgroups of patients with infarction and lacunar cerebral ischemia (p>0.05), as well as between females and males (p>0.05). Along with significantly increased fibrinogen level (4.65?1 g/l, in the controls - 2.83?0.64 g/l, p<0.001), significantly higher triglycerides (2.04?0.76 mmol/l, in the controls - 1.38+0.54 mmol/l, p<0.001) and lipoproteins(a) (0.405?0.29 g/l, in the controls -0.172?0.14 g/l, p<0.001) were found, correlating with higher plasma PAI-1 level in these patients. The increased plasma level of PAI-1 pointed to possibility of decreased fibrinolytic activity in pathogenesis of ischemie stroke, as well as, risk of reinsult, which had been the greatest after the onset of stroke and declined gradually within several weeks.

Tissue Plasminogen Activator in Human Megakaryocytes and Platelets: Immunocytochemical Localization, Immunoblotting and Zymographic Analysis

1988 ◽  
Vol 59 (03) ◽  
pp. 529-534 ◽  
Author(s):  
C Jeanneau ◽  
Y Sultan
Keyword(s):  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Fibrinolytic Activity ◽  
Blood Platelets ◽  
Fibrinolytic System ◽  
Plasminogen Activation ◽  
Sds Page ◽  
Tissue Plasminogen ◽  
Zymographic Analysis

SummaryTwo approaches were used to identify and characterize the presence of tissue plasminogen activator (t-PA) in megakaryocytes and platelets. We investigated the fibrinolytic activity of human megakaryocytes (MK) and platelets. The presence of t-PA antigen in megakaryocytes and platelets was demonstrated using immunocytochemical techniques and polyclonal or monoclonal antibodies specific for t-PA. When cells were applied to fibrin plates, lysis zones developed around isolated human megakaryocytes, whereas no fibrinolytic activity appeared when either intact washed platelets or platelet lysate were deposited. After SDS-PAGE of platelet and MK extracts (Triton X-100) immunoblotting and peroxidase staining identified t-PA antigen in several bands. Zymographic analysis of SDS-PAGE carried out on fibrin film overlays identified one or two zones corresponding to free or complexed t-PA. These results indicate that t-PA is present in platelets as well as in the precursor cells, however, in platelets, t-PA may not be immediately available for plasminogen activation and fibrin degradation. From our findings and from previous work of others, it appears that platelets may either activate or inhibit the fibrinolytic system. Therefore the conditions of plasminogen activation by platelet t-PA and plasmin inhibition by platelet α2-antiplasmin or other inhibitors have to be precised before the role of platelets in clot dissolution is understood.The physiological role of platelets in fibrinolysis and clot dissolution remains unclear. In 1953, the antifibrinolytic activity of blood platelets was demonstrated (1) and in the early 1960’s a fibrinolytic activity, increasing with platelet concentration in the experimental system, was shown (2, 3). In 1979, it was demonstrated that metabolically active platelets were necessary for platelets to play a role in the fibrinolytic system (4). More recently it was established by Plow and Collen (5) that the specific plasmin inhibitor, α2-antiplasmin is a constituent of platelet α-granules.In the present study, we investigated the fibrinolytic components and activity of human megakaryocytes and platelets, using zymographic and immunochemical techniques. We report here our observations that human megakaryocytes and platelets contain tissue plasminogen (t-PA) which possesses fibrinolytic activity.

A New Hypothesis: Possible Mechanisms in the Involvement of the Increased Plasminogen Activator Activity in Branching Regions of the Aorta in the Initiation of Atherosclerosis

1980 ◽  
Vol 43 (02) ◽  
pp. 141-146 ◽  
Author(s):  
A Smokovitis
Keyword(s):  
Plasminogen Activator ◽  
Early Life ◽  
Fibrinolytic Activity ◽  
Atherosclerotic Lesion ◽  
Protective Role ◽  
Fibrinolytic System ◽  
Actual Role ◽  
Plasminogen Activator Activity ◽  
New Hypothesis

SummaryBranching regions of the aorta are predilection regions for atherosclerosis. The intima in the branching regions of the normal aorta shows a constantly increased plasminogen activator activity from early life. At these areas, the endothelium is also damaged, it shows increased permeability, etc. The constantly increased plasminogen activator activity (local plasmin production) might play a protective role or on the contrary might participate in the initiation of atherosclerosis at the branching regions through a number of proved or suggested mechanisms.No matter what the actual role of the locally increased plasminogen activator activity in the initiation of atherosclerosis is, the role of the fibrinolytic system in the progression of the atherosclerotic lesion seems to be clear. There is an accumulation of evidence that the impaired fibrinolytic activity in atherosclerotics participates in the progression and the complications of the disease.

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