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Purpura Fulminans
Purpura fulminans is an acute, often fatal, thrombotic disorder which manifests as blood spots, bruising and discolouration of the skin resulting from coagulation in small blood vessels within the skin and rapidly leads to skin necrosis and disseminated intravascular coagulation. Causes Purpura fulminans is caused by defects in the protein C anticoagulant pathway. Identification of the cause of purpura fulminans often depends on the patient's age and circumstances of presentation. Congenital protein C deficiency Congenital (inherited) defects in protein C activity are autosomal dominant and may be partial or severe loss of function. Hundreds of natural mutations of the protein C gene (PROC) have been identified. Acquired protein C deficiency Acquired protein C deficiency is caused by either depletion of available protein C in plasma or decreased protein C synthesis (caused by administration of vitamin K antagonists, severe liver failure or complications of prematurity). Severe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrombosis
Thrombosis () is the formation of a Thrombus, blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (thrombocytes) and fibrin to form a blood clot to prevent blood loss. Even when a blood vessel is not injured, blood clots may form in the body under certain conditions. A clot, or a piece of the clot, that breaks free and begins to travel around the body is known as an embolus. Thrombosis can cause serious conditions such as stroke and heart attack. Thrombosis may occur in veins (venous thrombosis) or in arteries (arterial thrombosis). Venous thrombosis (sometimes called DVT, deep vein thrombosis) leads to a blood clot in the affected part of the body, while arterial thrombosis (and, rarely, severe venous thrombosis) affects the blood supply and leads to damage of the tissue supplied by that artery (ischemia and necrosis). A piece of either an arterial or a v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asplenia
Asplenia is the absence of normal spleen function and is associated with some serious infection risks. Hyposplenism is the condition of reduced ('hypo-'), but not absent, splenic functioning. ''Functional'' asplenia occurs when splenic tissue is present but does not work well (e.g. sickle-cell disease, polysplenia) such patients are managed as if asplenic while in ''anatomic'' asplenia, the spleen itself is absent. Causes Congenital * Congenital asplenia is rare. There are two distinct types of genetic disorders: heterotaxy syndromeOnline Mendelian Inheritance in Man. OMIM entry 208530: Right atrial isomerism; RAI. Johns Hopkins University/ref> and isolated congenital asplenia.Online Mendelian Inheritance in Man. Johns Hopkins UniversityOMIM entry 271400: Asplenia, isolated congenital; ICAS. * polysplenia Acquired Acquired asplenia occurs for several reasons: * Following splenectomy due to splenic rupture from trauma or because of tumor * After splenectomy with the ''goal'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Von Willebrand Factor
Von Willebrand factor (VWF) () is a blood glycoprotein that promotes primary hemostasis, specifically, platelet adhesion. It is deficient and/or defective in von Willebrand disease and is involved in many other diseases, including thrombotic thrombocytopenic purpura, Heyde's syndrome, and possibly hemolytic–uremic syndrome. Increased plasma levels in many cardiovascular, neoplastic, metabolic (e.g. diabetes), and connective tissue diseases are presumed to arise from adverse changes to the endothelium, and may predict an increased risk of thrombosis. Biochemistry Synthesis VWF is a large multimeric glycoprotein present in blood plasma and produced constitutively as ultra-large VWF in endothelium (in the Weibel–Palade bodies) and megakaryocytes (α-granules of platelets). Structure VWF is synthesized as a prepropeptide comprising 2813 amino acids in endothelial cells and megakaryocytes. The prepropeptide includes a 22-amino acid signal peptide (SP), a 741-amino acid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Factor VIII
Coagulation factor VIII (Factor VIII, FVIII, also known as anti-hemophilic factor (AHF)) is an essential blood clotting protein. In humans, it is encoded by ''F8'' gene. Defects in this gene result in hemophilia A, an X-linked bleeding disorder. Factor VIII is produced in the liver's liver sinusoid, sinusoidal cells and endothelial cells outside the liver throughout the body. This protein circulates in the bloodstream in an inactive form, bound to another molecule called von Willebrand factor, until an injury that damages blood vessels occurs. In response to injury, coagulation factor VIII is activated and separates from von Willebrand factor. The active protein (sometimes written as coagulation factor VIIIa) interacts with another coagulation factor called factor IX. This interaction sets off a chain of additional chemical reactions that form a blood clot. Factor VIII participates in blood coagulation; it is a cofactor for factor IXa, which, in the presence of Ca2+ and phosph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antithrombin
Antithrombin (AT) is a small glycoprotein that inactivates several enzymes of the coagulation system. It is a 464-amino-acid protein produced by the liver. It contains three disulfide bonds and a total of four possible glycosylation sites. α-Antithrombin is the dominant form of antithrombin found in blood plasma and has an oligosaccharide occupying each of its four glycosylation sites. A single glycosylation site remains consistently un-occupied in the minor form of antithrombin, β-antithrombin. Its activity is increased manyfold by the anticoagulant drug heparin, which enhances the binding of antithrombin to thrombin, factor IIa (thrombin) and factor Xa. Structure Antithrombin is also termed antithrombin III (AT III). The designations antithrombin I through to antithrombin IV originate in early studies carried out in the 1950s by Seegers, Johnson and Fell. Antithrombin I (AT I) refers to the binding of thrombin to fibrin, after thrombin has activated fibrinogen, at a non-ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Transcription
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residues i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tumour Necrosis Factor
Tumor necrosis factor (TNF), formerly known as TNF-α, is a chemical messenger produced by the immune system that induces inflammation. TNF is produced primarily by activated macrophages, and induces inflammation by binding to its receptors on other cells. It is a member of the tumor necrosis factor superfamily, a family of transmembrane proteins that are cytokines, chemical messengers of the immune system. Excessive production of TNF plays a critical role in several inflammatory diseases, and TNF-blocking drugs are often employed to treat these diseases. TNF is produced primarily by macrophages but is also produced in several other cell types, such as T cells, B cells, dendritic cells, and mast cells. It is produced rapidly in response to pathogens, cytokines, and environmental stressors. TNF is initially produced as a type II transmembrane protein (tmTNF), which is then cleaved by TNF alpha converting enzyme (TACE) into a soluble form (sTNF) and secreted from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interleukin-1
The Interleukin-1 family (IL-1 family) is a group of 11 cytokines that plays a central role in the regulation of immune and inflammatory responses to infections or sterile insults. Discovery Discovery of these cytokines began with studies on the pathogenesis of fever. The studies were performed by Eli Menkin and Paul Beeson in 1943–1948 on the fever-producing properties of proteins released from rabbit peritoneal exudate cells. These studies were followed by contributions of several investigators, who were primarily interested in the link between fever and infection/inflammation. The basis for the term "interleukin" was to streamline the growing number of biological properties attributed to soluble factors from macrophages and lymphocytes. IL-1 was the name given to the macrophage product, whereas IL-2 was used to define the lymphocyte product. At the time of the assignment of these names, there was no amino acid sequence analysis known and the terms were used to define b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytokines
Cytokines () are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are produced by a broad range of cells, including immune cells like macrophages, B cell, B lymphocytes, T cell, T lymphocytes and mast cells, as well as Endothelium, endothelial cells, fibroblasts, and various stromal cells; a given cytokine may be produced by more than one type of cell. Due to their size, cytokines cannot cross the lipid bilayer of cells to enter the cytoplasm and therefore typically exert their functions by interacting with specific cytokine receptor, cytokine receptors on the target cell surface. Cytokines are especially important in the immune system; cytokines modulate the balance between humoral immunity, humoral and cell-mediated immunity, cell-based immune responses, and they regulate the maturation, growth, and responsiveness of particular cell populations. Some cytokines enhance or inhibit the action of other cytokines in complex way ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endothelial Dysfunction
In blood vessel diseases, endothelial dysfunction is an unhealthy state of the the cells that line the blood vessels (endothelium). The main cause of endothelial dysfunction is impaired bioavailability of nitric oxide. In addition to acting as a semipermeable membrane, the endothelium is responsible for maintaining vascular tone and regulating oxidative stress by releasing mediators, such as nitric oxide, prostacyclin and endothelin, and by controlling local angiotensin-II activity. Dysfunctional endothelium is characterized by constricted blood vessels, increased ability of chemicals to flow through blood vessel walls, blood clots, and inflammation. This pathological state is often associated with elevated levels of biomarkers such as prothrombin time, D-dimer, von Willebrand factor, fibrin degradation products, C-reactive protein (CRP), ferritin, Interleukin 6 (IL-6), and plasma creatinine. The result of this endothelial dysregulation is a cascade of harmful effects, inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complement System
The complement system, also known as complement cascade, is a part of the humoral, innate immune system and enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen's cell membrane. Despite being part of the innate immune system, the complement system can be recruited and brought into action by antibodies generated by the adaptive immune system. The complement system consists of a number of small, inactive, liver synthesized protein precursors circulating in the blood. When stimulated by one of several triggers, proteases in the system cleave specific proteins to release cytokines and initiate an amplifying cascade of further cleavages. The end result of this ''complement activation'' or ''complement fixation'' cascade is stimulation of phagocytes to clear foreign and damaged material, inflammation to attract additional phagocytes, and activation of the cell-killi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inflammatory Response
Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', ''dolor'', ''rubor'', ''tumor'', and ''functio laesa''). Inflammation is a generic response, and therefore is considered a mechanism of innate immunity, whereas adaptive immunity is specific to each pathogen. Inflammation is a protective response involving immune cells, blood vessels, and molecular mediators. The function of inflammation is to eliminate the initial cause of cell injury, clear out damaged cells and tissues, and initiate tissue repair. Too little inflammation could lead to progressive tissue destruction by the harmful stimulus (e.g. bacteria) and compromise the survival of the organism. However inflammation can also have negative effects. Too much inflammation, in the form of chronic inflammation, is associated with various ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
