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Dilute Russell's Viper Venom Time
Dilute Russell's viper venom time (dRVVT) is a laboratory test often used for detection of lupus anticoagulant (LA). It is an assessment of the time for blood to clot in the presence of a diluted amount of venom from Russell's viper (''Daboia russelii''), a highly venomous snake native to the Indian subcontinent and named after the herpetologist Patrick Russell. History Russell's viper venom (RVV) was known to clot blood many years ago. It was widely used as a styptic to clot minor wounds when razor blades were more commonly used for shaving (e.g. "Stypven", Burroughs-Wellcome Pharma). RVV came to be useful in laboratory tests for blood clotting factors V, X, prothrombin and phospholipid. It was first used in clotting tests for lupus anticoagulant (LA) in an individual case in 1975. The "dilute Russell's viper venom time (dRVVT)" test was then applied in 1985 to detect LA in a large number of patients and it became more widely used for this purpose. This multi-step method invo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daboia Head
''Daboia'' is a genus of vipers.. Species The following four species are recognized as being valid: *''Daboia mauritanica'' – Moorish viper *''Daboia palaestinae'' – Palestine viper *''Daboia russelii'' – Russell's viper *''Daboia siamensis'' – eastern Russell's viper In the future, more species may be added to ''Daboia''. Obst (1983) reviewed the genus and suggested that it be extended to include ''Macrovipera lebetina'', ''Daboia palaestinae'', and '' M. xanthina''. Groombridge (1980, 1986) united ''V. palaestinae'' and ''Daboia'' as a clade based on a number of shared apomorphies In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to hav ..., including snout shape and head color pattern. Lenk et al. (2001) found support for this idea based on molecular evidence, suggesting tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clotting Time
Clotting time is a general term for the time required for a sample of blood to form a clot, or, in medical terms, coagulate. The term "clotting time" is often used when referring to tests such as the prothrombin time (PT), activated partial thromboplastin time (aPTT or PTT), activated clotting time (ACT), thrombin time (TT), or Reptilase time. These tests are coagulation studies performed to assess the natural clotting ability of a sample of blood. In a clinical setting, healthcare providers will order one of these tests to evaluate a patient's blood for any abnormalities in the time it takes for their blood to clot. Each test involves adding a specific substance to the blood and measuring the time until the blood forms fibrin which is one of the first signs of clotted blood. Each test points to a different component of the clotting sequence which is made up of coagulation factors that help form clots. Abnormal results could be due to a number of reasons including, but, not lim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antiphospholipid Syndrome
Antiphospholipid syndrome, or antiphospholipid antibody syndrome (APS or APLS), is an autoimmune, hypercoagulable state caused by antiphospholipid antibodies. APS can lead to blood clots (thrombosis) in both arteries and veins, pregnancy-related complications, and other symptoms like low platelets, kidney disease, heart disease, and rash. Although the exact etiology of APS is still not clear, genetics is believed to play a key role in the development of the disease. Diagnosis is made based on symptoms and testing, but sometimes research criteria are used to aid in diagnosis. The research criteria for definite APS requires one clinical event (i.e. thrombosis or pregnancy complication) and two positive blood test results spaced at least three months apart that detect lupus anticoagulant, anti-apolipoprotein antibodies, and/or anti-cardiolipin antibodies. Antiphospholipid syndrome can be primary or secondary. • Primary antiphospholipid syndrome occurs in the absence of any ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ELISA
The enzyme-linked immunosorbent assay (ELISA) (, ) is a commonly used analytical biochemistry assay, first described by Eva Engvall and Peter Perlmann in 1971. The assay is a solid-phase type of enzyme immunoassay (EIA) to detect the presence of a ligand (commonly an amino acid) in a liquid sample using antibodies directed against the ligand to be measured. ELISA has been used as a medical diagnosis, diagnostic tool in medicine, plant pathology, and biotechnology, as well as a quality control check in various industries. In the most simple form of an ELISA, antigens from the sample to be tested are attached to a surface. Then, a matching antibody is applied over the surface so it can bind the antigen. This antibody is linked to an enzyme, and then any unbound antibodies are removed. In the final step, a substance containing the enzyme's Enzyme substrate, substrate is added. If there was binding, the subsequent reaction produces a detectable signal, most commonly a color change. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anticardiolipin Antibodies
Anti-cardiolipin antibodies (ACA) are antibodies often directed against cardiolipin and found in several diseases, including syphilis, antiphospholipid syndrome, livedoid vasculitis, vertebrobasilar insufficiency, Behçet's syndrome, idiopathic spontaneous abortion, and systemic lupus erythematosus (SLE). They are a form of anti-mitochondrial antibody. In SLE, anti-DNA antibodies and anti-cardiolipin antibodies may be present individually or together; the two types of antibodies act independently. This is in contrast to rheumatoid arthritis with systemic sclerosis (scleroderma) because anti-cardiolipin antibodies are present in both conditions, and therefore may tie the two conditions together. Anti-cardiolipin antibodies can be classified in two ways: * As IgM, IgG or IgA * As β2-glycoprotein dependent or independent ** In autoimmune disease, ACA are beta-2 glycoprotein dependent ** In syphilis, ACA are beta-2 glycoprotein independent and can be assayed using the Venereal Dise ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serological
Serology is the scientific study of serum and other body fluids. In practice, the term usually refers to the diagnostic identification of antibodies in the serum. Such antibodies are typically formed in response to an infection (against a given microorganism), against other foreign proteins (in response, for example, to a mismatched blood transfusion), or to one's own proteins (in instances of autoimmune disease). In either case, the procedure is simple. Serological tests Serological tests are diagnostic methods that are used to identify antibodies and antigens in a patient's sample. Serological tests may be performed to diagnose infections and autoimmune illnesses, to check if a person has immunity to certain diseases, and in many other situations, such as determining an individual's blood type. Serological tests may also be used in forensic serology to investigate crime scene evidence. Several methods can be used to detect antibodies and antigens, including ELISA, agglutinatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antiphospholipid Syndrome
Antiphospholipid syndrome, or antiphospholipid antibody syndrome (APS or APLS), is an autoimmune, hypercoagulable state caused by antiphospholipid antibodies. APS can lead to blood clots (thrombosis) in both arteries and veins, pregnancy-related complications, and other symptoms like low platelets, kidney disease, heart disease, and rash. Although the exact etiology of APS is still not clear, genetics is believed to play a key role in the development of the disease. Diagnosis is made based on symptoms and testing, but sometimes research criteria are used to aid in diagnosis. The research criteria for definite APS requires one clinical event (i.e. thrombosis or pregnancy complication) and two positive blood test results spaced at least three months apart that detect lupus anticoagulant, anti-apolipoprotein antibodies, and/or anti-cardiolipin antibodies. Antiphospholipid syndrome can be primary or secondary. • Primary antiphospholipid syndrome occurs in the absence of any ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rivaroxaban
Rivaroxaban, sold under the brand name Xarelto among others, is an anticoagulant medication (blood thinner) used to treat and reduce the risk of blood clots. Specifically it is used to treat deep vein thrombosis and pulmonary emboli and prevent blood clots in atrial fibrillation and following hip or knee surgery. It is taken by mouth. Common side effects include bleeding. Other serious side effects may include spinal hematoma and anaphylaxis. It is unclear if use in pregnancy and breastfeeding is safe. Compared to warfarin it has fewer interactions with other medications. It works by blocking the activity of the clotting protein factor Xa. Rivaroxaban was patented in 2007 and approved for medical use in the United States in 2011. It is available as a generic medication. It is on the World Health Organization's List of Essential Medicines. In 2022, it was the 90th most commonly prescribed medication in the United States, with more than 7million prescriptions. Medical use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mixing Study
Mixing studies are tests performed on blood plasma of patients or test subjects to distinguish factor deficiencies from factor inhibitors, such as lupus anticoagulant, or specific factor inhibitors, such as antibodies directed against factor VIII. Mixing studies are screening tests widely performed in coagulation laboratories. The basic purpose of these tests is to determine the cause of prolongation of Prothrombin Time (PT), Partial Thromboplastin Time, or sometimes of thrombin time (TT). Mixing studies take advantage of the fact that factor levels that are 50 percent of normal should give a normal Prothrombin time (PT) or Partial thromboplastin time (PTT) result. Test method Fresh normal plasma has all the blood coagulation factors with normal levels. If the problem is a simple factor deficiency, mixing the patient plasma 1:1 with plasma that contains 100% of the normal factor level results in a level ≥50% in the mixture (say the patient has an activity of 0%; the average ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibrin
Fibrin (also called Factor Ia) is a fibrous protein, fibrous, non-globular protein involved in the Coagulation, clotting of blood. It is formed by the action of the protease thrombin on fibrinogen, which causes it to polymerization, polymerize. The polymerized fibrin, together with platelets, forms a hemostasis, hemostatic plug or clot over a wound site. When the lining of a blood vessel is broken, platelets are attracted, forming a platelet plug. These platelets have thrombin receptors on their surfaces that bind serum thrombin molecules, which in turn convert soluble fibrinogen in the serum into fibrin at the wound site. Fibrin forms long strands of tough insoluble protein that are bound to the platelets. Factor XIII completes the cross-linking of fibrin so that it hardens and contracts. The cross-linked fibrin forms a mesh atop the platelet plug that completes the clot. Fibrin was discovered by Marcello Malpighi in 1666. Role in disease Excessive generation of fibrin due ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lupus Anticoagulant
Lupus anticoagulant is an immunoglobulin that binds to phospholipids and proteins associated with the cell membrane. Its name is a partial misnomer, as it is actually a prothrombotic antibody ''in vivo''. The name derives from their properties ''in vitro'', as these antibodies increase coagulation times in laboratory tests such as the activated partial thromboplastin time (aPTT). Investigators speculate that the antibodies interfere with phospholipids used to induce in vitro coagulation. In vivo, the antibodies are thought to interact with platelet membrane phospholipids, increasing adhesion and aggregation of platelets, which accounts for the in vivo prothrombotic characteristics. The condition was first described by hematologist C. Lockard Conley in 1952. Terminology Both words in the term "lupus anticoagulant" can be misleading: * Most patients with a lupus anticoagulant do not actually have lupus erythematosus, and only a small proportion will proceed to develop this disease ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
