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The average life span of circulating platelets is 8 to 9 days. [17] Life span of individual platelets is controlled by the internal apoptotic regulating pathway, which has a Bcl-x L timer. [18] Old platelets are destroyed by phagocytosis in the spleen and liver.
They keep for up to five to seven days. [1] Platelet transfusions came into medical use in the 1950s and 1960s. [1] [5] It is on the World Health Organization's List of Essential Medicines. [6] [7] Some versions of platelets have had the white blood cells partially removed or been gamma irradiated which have specific benefits for certain ...
They circulate in the blood of mammals and are involved in hemostasis, leading to the formation of blood clots. Platelets release thread-like fibers to form these clots. The normal range (99% of population analyzed) for platelets is 150,000 to 450,000 per cubic millimeter. [6] If the number of platelets is too low, excessive bleeding can occur.
Polonium in the body has a biological half-life of about 30 to 50 days. Caesium in the body has a biological half-life of about one to four months. Mercury (as methylmercury) in the body has a half-life of about 65 days. Lead in the blood has a half life of 28–36 days. [29] [30] Lead in bone has a biological half-life of about ten years.
Platelets have a life span of 5 to 9 days. Because of this, the U.S. Food and Drug Administration (FDA) expires transfuse-able platelets 5 days post-collection. Typically, hPL is produced from expired platelets that have been stored in frozen conditions no later than 7 days post-collection.
Chromium-51 is a synthetic radioactive isotope of chromium having a half-life of 27.7 days and decaying by electron capture with emission of gamma rays (0.32 MeV); it is used to label red blood cells for measurement of mass or volume, survival time, and sequestration studies, for the diagnosis of gastrointestinal bleeding, and to label platelets to study their survival.
In this situation it is generally uncommon to talk about half-life in the first place, but sometimes people will describe the decay in terms of its "first half-life", "second half-life", etc., where the first half-life is defined as the time required for decay from the initial value to 50%, the second half-life is from 50% to 25%, and so on.
Factor V is produced by megakaryocytes, which produce platelets and platelet-derived factor V, and hepatocytes, which produce plasma-derived factor V. [9] The molecule circulates in plasma as a single-chain molecule with a plasma half-life of 12–36 hours. [10] Factor V is able to bind to activated platelets and is activated by thrombin.