Platelet
A Platelet is a cell fragment derived from precursor megakaryocytes.
- AKA: Thrombocyte.
- Context:
- It can (typically) be a component of Mammalian Blood Serum.
- It can have an average lifespan of 5 to 9 days.
- It can be responsible for Coagulation.
- It can (typically) have an concentration in human blood ranging 140,000 to 450,000 per μl.
- …
- Counter-Example(s):
- See: Blood, Serological Test, Coagulation Disorder, ITP, Bone Marrow, Haematopoietic System, Blood Clot.
References
2011
- http://en.wikipedia.org/wiki/Platelet
- Platelets, or thrombocytes (from Greek θρόμβος, "clot" and κύτος, "cell"), are small, irregularly shaped clear cell fragments (i.e. cells that do not have a nucleus containing DNA), 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes. The average lifespan of a platelet is normally just 5 to 9 days. Platelets are a natural source of growth factors. They circulate in the blood of mammals and are involved in hemostasis, leading to the formation of blood clots.
If the number of platelets is too low, excessive bleeding can occur. However, if the number of platelets is too high, blood clots can form (thrombosis), which may obstruct blood vessels and result in such events as a stroke, myocardial infarction, pulmonary embolism or the blockage of blood vessels to other parts of the body, such as the extremities of the arms or legs. An abnormality or disease of the platelets is called a thrombocytopathy,[1] which could be either a low number of platelets (thrombocytopenia), a decrease in function of platelets (thrombasthenia), or an increase in the number of platelets (thrombocytosis). There are disorders that reduce the number of platelets, such as heparin-induced thrombocytopenia (HIT) or thrombotic thrombocytopenic purpura (TTP) that typically cause thromboses, or clots, instead of bleeding.
Platelets release a multitude of growth factors including Platelet-derived growth factor (PDGF), a potent chemotactic agent, and TGF beta, which stimulates the deposition of extracellular matrix. Both of these growth factors have been shown to play a significant role in the repair and regeneration of connective tissues. Other healing-associated growth factors produced by platelets include basic fibroblast growth factor, insulin-like growth factor 1, platelet-derived epidermal growth factor, and vascular endothelial growth factor. Local application of these factors in increased concentrations through Platelet-rich plasma (PRP) has been used as an adjunct to wound healing for several decades.[2][3][4][5][6][7][8]
- Platelets, or thrombocytes (from Greek θρόμβος, "clot" and κύτος, "cell"), are small, irregularly shaped clear cell fragments (i.e. cells that do not have a nucleus containing DNA), 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes. The average lifespan of a platelet is normally just 5 to 9 days. Platelets are a natural source of growth factors. They circulate in the blood of mammals and are involved in hemostasis, leading to the formation of blood clots.
- ↑ Maton, Anthea; Jean Hopkins, Charles William McLaughlin, Susan Johnson, Maryanna Quon Warner, David LaHart, Jill D. Wright (1993). Human Biology and Health. Englewood Cliffs NJ: Prentice Hall. ISBN 0-13-981176-1.
- ↑ O'Connell SM, Impeduglia T, Hessler K, Wang XJ, Carroll RJ, Dardik H (2008). "Autologous platelet-rich fibrin matrix as cell therapy in the healing of chronic lower-extremity ulcers". Wound Repair Regen 16 (6): 749–56. doi:10.1111/j.1524-475X.2008.00426.x. PMID 19128245.
- ↑ Sánchez M, Anitua E, Azofra J, Andía I, Padilla S, Mujika I (2007). "Comparison of surgically repaired Achilles tendon tears using platelet-rich fibrin matrices". Am J Sports Med 35 (2): 245–51. doi:10.1177/0363546506294078. PMID 17099241.
- ↑ Knighton DR, Ciresi KF, Fiegel VD, Austin LL, Butler EL (1986). "Classification and treatment of chronic nonhealing wounds. Successful treatment with autologous platelet-derived wound healing factors (PDWHF)". Ann. Surg. 204 (3): 322–30. PMC 1251286. PMID 3753059. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1251286.
- ↑ Knighton DR, Ciresi K, Fiegel VD, Schumerth S, Butler E, Cerra F (1990). "Stimulation of repair in chronic, nonhealing, cutaneous ulcers using platelet-derived wound healing formula". Surg Gynecol Obstet 170 (1): 56–60. PMID 2403699.
- ↑ Celotti F, Colciago A, Negri-Cesi P, Pravettoni A, Zaninetti R, Sacchi MC (2006). "Effect of platelet-rich plasma on migration and proliferation of SaOS-2 osteoblasts: role of platelet-derived growth factor and transforming growth factor-beta". Wound Repair Regen 14 (2): 195–202. doi:10.1111/j.1743-6109.2006.00110.x. PMID 16630109.
- ↑ McAleer JP, Sharma S, Kaplan EM, Persich G (2006). "Use of autologous platelet concentrate in a nonhealing lower extremity wound". Adv Skin Wound Care 19 (7): 354–63. doi:10.1097/00129334-200609000-00010. PMID 16943701.
- ↑ Driver VR, Hanft J, Fylling CP, Beriou JM (2006). "A prospective, randomized, controlled trial of autologous platelet-rich plasma gel for the treatment of diabetic foot ulcers". Ostomy Wound Manage 52 (6): 68–70, 72, 74 passim. PMID 16799184.