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Thromboxane-A Synthase
Thromboxane A synthase 1 (, platelet, cytochrome P450, family 5, subfamily A), also known as TBXAS1, is a cytochrome P450 enzyme that, in humans, is encoded by the ''TBXAS1'' gene. Function This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases that catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids, and other lipids. However, this protein is considered a member of the cytochrome P450 superfamily on the basis of sequence similarity rather than functional similarity. This endoplasmic reticulum membrane protein catalyzes the conversion of prostaglandin H2 to thromboxane A2, a potent vasoconstrictor and inducer of platelet aggregation, and also to 12-Hydroxyheptadecatrienoic acid (i.e. 12-(''S'')-hydroxy-5''Z'',8''E'',10''E''-heptadecatrienoic acid or 12-HHT) an agonist of Leukotriene B4 receptors (i.e. BLT2 receptors) and mediator of certain BLT2 receptor actions. The en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytochrome P450
Cytochromes P450 (CYPs) are a superfamily of enzymes containing heme as a cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are important for the clearance of various compounds, as well as for hormone synthesis and breakdown. In 1963, Estabrook, Cooper, and Rosenthal described the role of CYP as a catalyst in steroid hormone synthesis and drug metabolism. In plants, these proteins are important for the biosynthesis of defensive compounds, fatty acids, and hormones. CYP enzymes have been identified in all kingdoms of life: animals, plants, fungi, protists, bacteria, and archaea, as well as in viruses. However, they are not omnipresent; for example, they have not been found in ''Escherichia coli''. , more than 300,000 distinct CYP proteins are known. CYPs are, in general, the terminal oxidase enzymes in electron transfer chains, broadly categorized as P450-containing systems. The term "P450" is derived fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thromboxane
Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2. The distinguishing feature of thromboxanes is a 6-membered ether-containing ring. Thromboxane is named for its role in blood clot formation ( thrombosis). Production Thromboxane-A synthase, an enzyme found in platelets, converts the arachidonic acid derivative prostaglandin H2 to thromboxane. Mechanism Thromboxane acts by binding to any of the thromboxane receptors, G-protein-coupled receptors coupled to the G protein Gq. Functions Thromboxane is a vasoconstrictor and a potent hypertensive agent, and it facilitates platelet aggregation. It is in homeostatic balance in the circulatory system with prostacyclin, a related compound. The mechanism of secretion of thromboxanes from platelets is still unclear. They act in the formation of blood clots and reduce blood flow to the site of a clot. If the cap of a vulnerable plaque erod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apoptosis
Apoptosis (from grc, ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes ( morphology) and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, DNA fragmentation, and mRNA decay. The average adult human loses between 50 and 70 billion cells each day due to apoptosis. For an average human child between eight and fourteen years old, approximately twenty to thirty billion cells die per day. In contrast to necrosis, which is a form of traumatic cell death that results from acute cellular injury, apoptosis is a highly regulated and controlled process that confers advantages during an organism's life cycle. For example, the separation of fingers and toes in a developing human embryo occurs because cells between the digits undergo apoptosis. Unlike necrosis, apoptosis produces cell fragments called apopt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Renal Cancer
Kidney cancer, also known as renal cancer, is a group of cancers that starts in the kidney. Symptoms may include blood in the urine, lump in the abdomen, or back pain. Fever, weight loss, and tiredness may also occur. Complications can include spread to the lungs or brain. The main types of kidney cancer are renal cell cancer (RCC), transitional cell cancer (TCC), and Wilms tumor. RCC makes up approximately 80% of kidney cancers, and TCC accounts for most of the rest. Risk factors for RCC and TCC include smoking, certain pain medications, previous bladder cancer, being overweight, high blood pressure, certain chemicals, and a family history. Risk factors for Wilms tumor include a family history and certain genetic disorders such as WAGR syndrome. Diagnosis maybe suspected based on symptoms, urine testing, and medical imaging. It is confirmed by tissue biopsy. Treatment may include surgery, radiation therapy, chemotherapy, immunotherapy, and targeted therapy. Kidney ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prostate Cancer
Prostate cancer is cancer of the prostate. Prostate cancer is the second most common cancerous tumor worldwide and is the fifth leading cause of cancer-related mortality among men. The prostate is a gland in the male reproductive system that surrounds the urethra just below the bladder. It is located in the hypogastric region of the abdomen. To give an idea of where it is located, the bladder is superior to the prostate gland as shown in the image The rectum is posterior in perspective to the prostate gland and the ischial tuberosity of the pelvic bone is inferior. Only those who have male reproductive organs are able to get prostate cancer. Most prostate cancers are slow growing. Cancerous cells may spread to other areas of the body, particularly the bones and lymph nodes. It may initially cause no symptoms. In later stages, symptoms include pain or difficulty urinating, blood in the urine, or pain in the pelvis or back. Benign prostatic hyperplasia may produce similar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Papillary Thyroid Carcinoma
Papillary thyroid cancer or papillary thyroid carcinoma is the most common type of thyroid cancer, representing 75 percent to 85 percent of all thyroid cancer cases.Chapter 20 in: 8th edition. It occurs more frequently in women and presents in the 20–55 year age group. It is also the predominant cancer type in children with thyroid cancer, and in patients with thyroid cancer who have had previous radiation to the head and neck. It is often well- differentiated, slow-growing, and localized, although it can metastasize. Diagnosis Papillary thyroid carcinoma is usually discovered on routine examination as an asymptomatic thyroid nodule that appears as a neck mass. In some instances, the mass may have produced local symptoms. This mass is normally referred to a fine needle aspiration biopsy (FNA) for investigation. FNA accuracy is very high and it is a process widely used in these cases. Other investigation methods include ultrasound imaging and nuclear scan. The ultrasound is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrombotic
Thrombosis (from Ancient Greek "clotting") 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 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 venous thrombus can break off as an embolus, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vasoconstriction
Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood vessels. The process is particularly important in controlling hemorrhage and reducing acute blood loss. When blood vessels constrict, the flow of blood is restricted or decreased, thus retaining body heat or increasing vascular resistance. This makes the skin turn paler because less blood reaches the surface, reducing the radiation of heat. On a larger level, vasoconstriction is one mechanism by which the body regulates and maintains mean arterial pressure. Medications causing vasoconstriction, also known as vasoconstrictors, are one type of medicine used to raise blood pressure. Generalized vasoconstriction usually results in an increase in systemic blood pressure, but it may also occur in specific tissues, causing a localized reducti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eicosanoids
Eicosanoids are signaling molecules made by the enzymatic or non-enzymatic oxidation of arachidonic acid or other polyunsaturated fatty acids (PUFAs) that are, similar to arachidonic acid, around 20 carbon units in length. Eicosanoids are a sub-category of oxylipins, i.e. oxidized fatty acids of diverse carbon units in length, and are distinguished from other oxylipins by their overwhelming importance as cell signaling molecules. Eicosanoids function in diverse physiological systems and pathological processes such as: mounting or inhibiting inflammation, allergy, fever and other immune responses; regulating the abortion of pregnancy and normal childbirth; contributing to the perception of pain; regulating cell growth; controlling blood pressure; and modulating the regional flow of blood to tissues. In performing these roles, eicosanoids most often act as autocrine signaling agents to impact their cells of origin or as paracrine signaling agents to impact cells in the pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thromboxanes
Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2. The distinguishing feature of thromboxanes is a 6-membered ether-containing ring. Thromboxane is named for its role in blood clot formation (thrombosis). Production Thromboxane-A synthase, an enzyme found in platelets, converts the arachidonic acid derivative prostaglandin H2 to thromboxane. Mechanism Thromboxane acts by binding to any of the thromboxane receptors, G-protein-coupled receptors coupled to the G protein Gq. Functions Thromboxane is a vasoconstrictor and a potent hypertensive agent, and it facilitates platelet aggregation. It is in homeostatic balance in the circulatory system with prostacyclin, a related compound. The mechanism of secretion of thromboxanes from platelets is still unclear. They act in the formation of blood clots and reduce blood flow to the site of a clot. If the cap of a vulnerable plaque erodes or ruptu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thromboxane
Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2. The distinguishing feature of thromboxanes is a 6-membered ether-containing ring. Thromboxane is named for its role in blood clot formation ( thrombosis). Production Thromboxane-A synthase, an enzyme found in platelets, converts the arachidonic acid derivative prostaglandin H2 to thromboxane. Mechanism Thromboxane acts by binding to any of the thromboxane receptors, G-protein-coupled receptors coupled to the G protein Gq. Functions Thromboxane is a vasoconstrictor and a potent hypertensive agent, and it facilitates platelet aggregation. It is in homeostatic balance in the circulatory system with prostacyclin, a related compound. The mechanism of secretion of thromboxanes from platelets is still unclear. They act in the formation of blood clots and reduce blood flow to the site of a clot. If the cap of a vulnerable plaque erod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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