School custodian dies from blood clots after fall from ladder.

SummaryIn vitro whole blood clots of various ages, experimental thrombi produced in the jugular vein of rabbits and human thrombi from arteries and veins were examined in semi-thin sections and by means of electron microscopy.In all types of clots examined a typical course of retraction was found. Retraction starts with a dense excentrical focus which grows into a densification ring. After 24 hours the entire clot becomes almost homogeneously dense; later a secondary swelling sets in.Shortly after coagulation the erythrocytes on the rim of the clot are bi-concave discs. They then assume the shape of crenate spheres, turn into smooth spheres and finally become indented ghosts which have lost the largest part of their contents. In the inner zone, which makes up the bulk of the clot, we observed bi-concave discs prior to retraction. After retraction we see no crenations but irregularly shaped erythrocytes. Once the secondary swelling sets in, the cross-section becomes polygonal and later spherical. After extensive hemolysis we observe the “retiform thrombus” made up of ghosts.Experimental and clinical thrombi present the same morphology but are differentiated from in vitro clots by: earlier hemolysis, immigration of leukocytes, formation of a rim layer consisting of fibrin and thrombocytes, and the symptoms of organization. Such symptoms of organization which definitely will prevent lysis with streptokinase were found relatively late in experimental and clinical thrombi. Capillary buds and capillary loops were never found in clinical thrombi prior to the third month.The morphological findings agree with earlier physical and enzymatic investigations. The observation that phenomena of reorganization occur relatively late and frequently only in the rim areas of large thrombi explains why lytic therapy is possible in some of the chronic obliterations.

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In Vitro Clot Lysis as a Potential Indicator of Thrombus Resistance to Fibrinolysis – Study in Healthy Subjects and Correlation with Blood Fibrinolytic Parameters

Thrombosis and Haemostasis ◽

10.1055/s-0038-1656041 ◽

1997 ◽

Vol 77 (04) ◽

pp. 725-729 ◽

Cited By ~ 11

Author(s):

Mario Colucci ◽

Silvia Scopece ◽

Antonio V Gelato ◽

Donato Dimonte ◽

Nicola Semeraro

Keyword(s):

Plasminogen Activator ◽

Clot Lysis ◽

Individual Response ◽

Plasminogen Activator Inhibitor 1 ◽

Autologous Plasma ◽

Wide Range ◽

Blood Clots ◽

Physiological Variations ◽

Pai 1

SummaryUsing an in vitro model of clot lysis, the individual response to a pharmacological concentration of recombinant tissue plasminogen activator (rt-PA) and the influence on this response of the physiological variations of blood parameters known to interfere with the fibrinolytic/thrombolytic process were investigated in 103 healthy donors. 125I-fibrin labelled blood clots were submersed in autologous plasma, supplemented with 500 ng/ml of rt-PA or solvent, and the degree of lysis was determined after 3 h of incubation at 37° C. Baseline plasma levels of t-PA, plasminogen activator inhibitor 1 (PAI-1), plasminogen, α2-anti-plasmin, fibrinogen, lipoprotein (a), thrombomodulin and von Willebrand factor as well as platelet and leukocyte count and clot retraction were also determined in each donor. rt-PA-induced clot lysis varied over a wide range (28-75%) and was significantly related to endogenous t-PA, PAI-1, plasminogen (p <0.001) and age (p <0.01). Multivariate analysis indicated that both PAI-1 antigen and plasminogen independently predicted low response to rt-PA. Surprisingly, however, not only PAI-1 but also plasminogen was negatively correlated with rt-PA-ginduced clot lysis. The observation that neutralization of PAI-1 by specific antibodies, both in plasma and within the clot, did not potentiate clot lysis indicates that the inhibitor, including the platelet-derived form, is insufficient to attenuate the thrombolytic activity of a pharmacological concentration of rt-PA and that its elevation, similarly to the elevation of plasminogen, is not the cause of clot resistance but rather a coincident finding. It is concluded that the in vitro response of blood clots to rt-PA is poorly influenced by the physiological variations of the examined parameters and that factors other than those evaluated in this study interfere with clot dissolution by rt-PA. In vitro clot lysis test might help to identify patients who may be resistant to thrombolytic therapy.

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Leukocytes and Thrombosis

Thrombosis and Haemostasis ◽

10.1055/s-0038-1656285 ◽

1965 ◽

Vol 13 (01) ◽

pp. 035-046 ◽

Cited By ~ 27

Author(s):

R. L Henry

Keyword(s):

Tissue Culture ◽

White Blood Cells ◽

Polymorphonuclear Neutrophils ◽

Mononuclear Leukocytes ◽

Amoeboid Movement ◽

Proliferating Cells ◽

Cell Tissue ◽

Blood Clots ◽

Platelet Aggregates ◽

To Come

SummaryWhite blood cells can no longer be considered simple trapped inclusions within thrombi. Their numbers in thrombi relative to blood counts increase with time. They appear to come from the blood flowing past the thrombus. They appear to migrate by amoeboid movement into the thrombic mass. Polymorphonuclear neutrophils have been shown to be lytic to fibrin and other proteins and thus can contribute to thrombus dissolution. There is increasing evidence that neutrophils may impart important cytotrophic function to proliferating cells during thrombus organization. Eosinophils are known to carr profibrinolysin and will release this precursor at sites of fibrin deposition. Mononuclear leukocytes can transform into fibroblasts in tissue culture and I consider a thrombus an ideal tissue culture medium. All of these cells can contribute to thrombus dissolution simply by mechanical weakening of the mass by migration into it, releasing enzymes, and allowing blood flow to carry away pieces of the thrombus as emboli. I extend my perspective on thrombosis by considering these intravascular solids as cell tissue cultures rather than simple blood clots or platelet aggregates.

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New tool could help identify people at high risk of repeat blood clots

10.3310/signal-000232 ◽

2016 ◽

Author(s):

Keyword(s):

High Risk ◽

Blood Clots

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Origin of myofibroblasts in the avascular capsule around free-floating intraperitoneal blood clots

Pathology ◽

10.3109/00313028309083503 ◽

1983 ◽

Vol 15 (3) ◽

pp. 253-264 ◽

Cited By ~ 35

Author(s):

Gordon R. Campbell ◽

G.B. Ryan

Keyword(s):

Blood Clots

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Nanodroplet-mediated catheter-directed sonothrombolysis of retracted blood clots

Microsystems & Nanoengineering ◽

10.1038/s41378-020-00228-9 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Leela Goel ◽

Huaiyu Wu ◽

Bohua Zhang ◽

Jinwook Kim ◽

Paul A. Dayton ◽

...

Keyword(s):

Drug Delivery ◽

Negative Pressure ◽

Boiling Point ◽

Clot Lysis ◽

Control Group ◽

Peak Negative Pressure ◽

Blood Clots ◽

Tissue Plasminogen ◽

First Time

AbstractOne major challenge in current microbubble (MB) and tissue plasminogen activator (tPA)-mediated sonothrombolysis techniques is effectively treating retracted blood clots, owing to the high density and low porosity of retracted clots. Nanodroplets (NDs) have the potential to enhance retracted clot lysis owing to their small size and ability to penetrate into retracted clots to enhance drug delivery. For the first time, we demonstrate that a sub-megahertz, forward-viewing intravascular (FVI) transducer can be used for ND-mediated sonothrombolysis, in vitro. In this study, we determined the minimum peak negative pressure to induce cavitation with low-boiling point phase change nanodroplets and clot lysis. We then compared nanodroplet mediated sonothrombolysis to MB and tPA mediate techniques. The clot lysis as a percent mass decrease in retracted clots was 9 ± 8%, 9 ± 5%, 16 ± 5%, 14 ± 9%, 17 ± 9%, 30 ± 8%, and 40 ± 9% for the control group, tPA alone, tPA + US, MB + US, MB + tPA + US, ND + US, and ND + tPA + US groups, respectively. In retracted blood clots, combined ND- and tPA-mediated sonothrombolysis was able to significantly enhance retracted clot lysis compared with traditional MB and tPA-mediated sonothrombolysis techniques. Combined nanodroplet with tPA-mediated sonothrombolysis may provide a feasible strategy for safely treating retracted clots.

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