Related Experiment Video
Updated: Jul 21, 2026
05:49
Procoagulant Platelet Characterization by Measuring Phosphatidylserine Exposure and Microvesicle Release from Human Purified Platelets
Published on: November 29, 2024
Characterization of human platelet vascular permeability-enhancing activity
The Journal of Clinical Investigation
|March 1, 1972
Summary
Human platelet proteins increase vascular permeability via histamine release and leukocyte infiltration. This study identifies cationic proteins from platelets as key mediators of these effects.
Area of Science:
- Biochemistry
- Immunology
- Hematology
Background:
- Platelets play a crucial role in hemostasis and inflammation.
- Platelet-derived factors are implicated in modulating vascular permeability.
Purpose of the Study:
- To investigate the role of human platelet cationic proteins in vascular permeability.
- To elucidate the mechanisms by which platelet proteins affect blood vessel permeability.
Main Methods:
- Partial purification of human platelet acid extract using DEAE-cellulose chromatography and Sephadex gel filtration.
- Assessment of the effects of purified protein fractions on vascular permeability in rabbit skin.
- Histological analysis of tissue responses, including edema and leukocyte infiltration.
Main Results:
- A heat-stable, cationic protein fraction (approx. 30,000 mol wt) induced a biphasic increase in vascular permeability.
- The acute permeability increase was histamine-dependent, while the delayed effect involved leukocytic infiltration.
- The purified fraction exhibited antiheparin activity.
Conclusions:
- Human platelet lysosomal release of cationic proteins contributes to increased vascular permeability.
- Mechanisms include endogenous histamine release and delayed chemotaxis, leading to edema and leukocyte infiltration.
- These findings highlight a novel role for platelet proteins in inflammatory processes.
Related Concept Videos
01:20Antiplatelet Drugs: Prostaglandin Synthesis, P2Y12 and Glycoprotein IIb/IIIa Inhibitors
Antiplatelet drugs emerge as frontline defenders against the insidious threat of thromboembolic diseases, where abnormal clots obstruct vital blood vessels. These drugs stand as bulwarks, inhibiting platelet aggregation and clot formation, thereby mitigating the risk of life-threatening conditions like myocardial infarction, coronary artery disease, and thrombotic strokes.
Prostaglandin synthesis inhibitors, exemplified by the widely known aspirin, wield their power by irreversibly acetylating...
Prostaglandin synthesis inhibitors, exemplified by the widely known aspirin, wield their power by irreversibly acetylating...
01:18Structure and Function of Platelets
The cell fragments known as platelets are disc-shaped, with an average diameter of about 3 μm and a thickness of roughly 1 μm. They play a crucial role in the body's vascular clotting system, which also involves plasma proteins, blood cells, and blood vessel tissues.
Platelets are continually replenished, circulating in the bloodstream for 9-12 days before being removed by phagocytes, primarily in the spleen. A microliter of circulating blood contains between 150,000 and 450,000 platelets, with...
Platelets are continually replenished, circulating in the bloodstream for 9-12 days before being removed by phagocytes, primarily in the spleen. A microliter of circulating blood contains between 150,000 and 450,000 platelets, with...
01:22Formation of the Platelet Plug
The platelet phase, the second stage of hemostasis, commences around 15-20 seconds after an injury. It follows and overlaps with the vascular phase, during which blood vessels constrict to minimize blood loss.
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...