In this process, the platelets are spun in a centrifuge and the excess plasma is removed, leaving 10 to 100 mL of platelet concentrate. Such volume-reduced platelets are normally transfused only to neonatal and pediatric patients when a large volume of plasma could overload the childs small circulatory system. The lower volume of plasma also reduces the chances of an adverse transfusion reaction to plasma proteins. Volume reduced platelets have a shelf life of only four hours. Wound therapy
Platelets release platelet-derived growth factor (PDGF), a potent chemotactic agent; and TGF beta, which stimulates the deposition of extracellular matrix; 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) is used as an adjunct in wound healing. Other animals
Instead of having platelets, non-mammalian vertebrates have nucleated thrombocytes, which resemble B lymphocytes in morphology. They aggregate in response to thrombin, but not to ADP, serotonin, nor adrenaline, as platelets do. History
George Gulliver in 1841 drew pictures of platelets using the twin lens (compound) microscope invented in 1830 by Joseph Jackson Lister. This microscope improved resolution sufficiently to make it possible to see platelets for the first time. William Addison in 1842 drew pictures of a platelet-fibrin clot. Lionel Beale in 1864 was the first to publish a drawing showing platelets. Max Schultze in 1865 described what he called "spherules", which he noted were much smaller than red blood cells, occasionally clumped, and were sometimes found in collections of fibrin material.
This theory is based on high incidence of dead parasites or ova within stone in autopsy findings. Diagnosis
The diagnosis can be suspected by imaging, with typical characteristics centering around appearance of the liver, typically with CT, ultrasound or MRI. Traits that raise suspicion for the infection include intra- and extra- hepatic dilatation and strictures with intraductal pigmented stones, usually in the absence of gallstones and with regions of segmental liver atrophy, particularly the lateral aspect of the left hepatic lobe. There is also reduced arborization of peripheral ducts. Approximately 5% of chronic infections go on to develop cholangiocarcinoma.Pathogenic bacteria responsible for the infection include E. coli, Klebsiella, Pseudomonas, and Proteus species. Anaerobes are a less frequent cause, and a culture positive for multiple strains can be common. When related to Clonorchis sinensis, definitive diagnosis is by identification of eggs by microscopic demonstration in faeces or in duodenal aspirate, but other sophisticated methods have been developed, such as ELISA, which has become the most important clinical technique. Diagnosis by detecting DNAs from eggs in faeces are also developed using PCR, real-time PCR, and LAMP, which are highly sensitive and specific. Treatment
The treatment of RPC involves management of sepsis during episodes of cholangitis with antibiotics, abscess drainage, and blood pressure support. With resistant infection, a surgical hepatectomy or hepaticocutaneousjejunostomy can be performed. Lifelong surveillance for malignancy is also usually necessary. See also
Cholangitis
Cholecystitis
Clonorchiasis
Clonorchis sinensis
Hepaticojejunostomy
Cirrhosis

References


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