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Endothelial Dysfunction
In vascular diseases, endothelial dysfunction is a systemic pathological state of the endothelium. Along with acting as a semi-permeable membrane, the endothelium is responsible for maintaining vascular tone and regulating oxidative stress by releasing mediators, such as nitric oxide, prostacyclin and endothelin, and controlling local angiotensin-II activity. Research Atherosclerosis Endothelial dysfunction may be involved in the development of atherosclerosis and may predate vascular pathology. Endothelial dysfunction can also lead to increased adherence of monocytes and macrophages, as well as promoting infiltration of LDL in the vessel wall. Dyslipidemia and hypertension are well known to contribute to endothelial dysfunction, and lowering blood pressure and LDL has been shown to improve endothelial function, particularly when lowered with ACE inhibitors, calcium channel blockers, and statins. Nitric oxide Nitric oxide (NO) suppresses platelet aggregation, inflammation, oxid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vascular Disease
Vascular disease is a class of diseases of the blood vessels – the arteries and veins of the circulatory system of the body. Vascular disease is a subgroup of cardiovascular disease. Disorders in this vast network of blood vessels can cause a range of health problems that can sometimes become severe. Types There are several types of vascular disease, and signs and symptoms can vary depending on the disease type. These types include: * Erythromelalgia - a rare peripheral vascular disease with syndromes that include burning pain, increased temperature, erythema and swelling that generally affect the hands and feet. * Peripheral artery disease – occurs when atheromatous plaques build up in the arteries that supply blood to the arms and legs, causing the arteries to narrow or become blocked. * Renal artery stenosis - the narrowing of renal arteries that carry blood to the kidneys from the aorta. * Buerger's disease – inflammation and swelling in small blood vessels, causing the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Statin
Statins, also known as HMG-CoA reductase inhibitors, are a class of lipid-lowering medications that reduce illness and mortality in those who are at high risk of cardiovascular disease. They are the most common cholesterol-lowering drugs. Low-density lipoprotein (LDL) carriers of cholesterol play a key role in the development of atherosclerosis and coronary heart disease via the mechanisms described by the lipid hypothesis. Statins are effective in lowering LDL cholesterol and so are widely used for primary prevention in people at high risk of cardiovascular disease, as well as in secondary prevention for those who have developed cardiovascular disease. Side effects of statins include muscle pain, increased risk of diabetes mellitus, and abnormal blood levels of liver enzymes. Additionally, they have rare but severe adverse effects, particularly muscle damage. They inhibit the enzyme HMG-CoA reductase which plays a central role in the production of cholesterol. High cholester ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flow-mediated Dilation
Flow-mediated dilation (FMD) refers to dilation (widening) of an artery when blood flow increases in that artery. The primary cause of FMD is release of nitric oxide by endothelial cells. To determine FMD, brachial artery dilation following a transient period of forearm ischemia is measured using ultrasound. Because the value of FMD can be compromised when improperly applied, attempts have been made to standardize the methodology for measuring FMD. Clinical significance FMD is a noninvasive measure of blood vessel health (endothelial dysfunction) which (when low) is at least as predictive of cardiovascular disease as traditional risk factors. Major cardiovascular disease associated with low FMD include cardiac death, myocardial infarction, and stroke. Low FMD is a stronger predictor of future cardiovascular disease events in patients with existing cardiovascular disease than in healthy normal persons. FMD is a sensitive marker for the amount of blood vessel damage caused by ci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minimally Invasive Procedures
Minimally invasive procedures (also known as minimally invasive surgeries) encompass surgical techniques that limit the size of incisions needed, thereby reducing wound healing time, associated pain, and risk of infection. Surgery by definition is invasive and many operations requiring incisions of some size are referred to as ''open surgery''. Incisions made during open surgery can sometimes leave large wounds that may be painful and take a long time to heal. Advancements in medical technologies have enabled the development and regular use of minimally invasive procedures. For example, endovascular aneurysm repair, a minimally invasive surgery, has become the most common method of repairing abdominal aortic aneurysms in the US as of 2003. The procedure involves much smaller incisions than the corresponding open surgery procedure of open aortic surgery. Interventional radiologists were the forerunners of minimally invasive procedures. Using imaging techniques, radiologists wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultrasonography
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies from person to person and is approximately 20 kilohertz (20,000 hertz) in healthy young adults. Ultrasound devices operate with frequencies from 20 kHz up to several gigahertz. Ultrasound is used in many different fields. Ultrasonic devices are used to detect objects and measure distances. Ultrasound imaging or sonography is often used in medicine. In the nondestructive testing of products and structures, ultrasound is used to detect invisible flaws. Industrially, ultrasound is used for cleaning, mixing, and accelerating chemical processes. Animals such as bats and porpoises use ultrasound for locating prey and obstacles. History Acoustics, the science of sound, starts as far back as Pythagoras in the 6th century BC, who wrote on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plethysmography
A plethysmograph is an instrument for measuring changes in volume within an organ or whole body (usually resulting from fluctuations in the amount of blood or air it contains). The word is derived from the Greek "plethysmos" (increasing, enlarging, becoming full), and "graphein" (to write). Organs studied Lungs Pulmonary plethysmographs are commonly used to measure the functional residual capacity (FRC) of the lungs—the volume in the lungs when the muscles of respiration are relaxed—and total lung capacity. In a traditional plethysmograph (or "body box"), the test subject, or patient, is placed inside a sealed chamber the size of a small telephone booth with a single mouthpiece. At the end of normal expiration, the mouthpiece is closed. The patient is then asked to make an inspiratory effort. As the patient tries to inhale (a maneuver which looks and feels like panting), the lungs expand, decreasing pressure within the lungs and increasing lung volume. This, in turn, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coronary Artery
The coronary arteries are the arterial blood vessels of coronary circulation, which transport oxygenated blood to the heart muscle. The heart requires a continuous supply of oxygen to function and survive, much like any other tissue or organ of the body. The coronary arteries wrap around the entire heart. The two main branches are the left coronary artery and right coronary artery. The arteries can additionally be categorized based on the area of the heart for which they provide circulation. These categories are called ''epicardial'' (above the epicardium, or the outermost tissue of the heart) and ''microvascular'' (close to the endocardium, or the innermost tissue of the heart). Reduced function of the coronary arteries can lead to decreased flow of oxygen and nutrients to the heart. Not only does this affect supply to the heart muscle itself, but it also can affect the ability of the heart to pump blood throughout the body. Therefore, any disorder or disease of the coronary ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angiography
Angiography or arteriography is a medical imaging technique used to visualize the inside, or lumen, of blood vessels and organs of the body, with particular interest in the arteries, veins, and the heart chambers. Modern angiography is performed by injecting a radio-opaque contrast agent into the blood vessel and imaging using X-ray based techniques such as fluoroscopy. The word itself comes from the Greek words ἀγγεῖον ''angeion'' 'vessel' and γράφειν ''graphein'' 'to write, record'. The film or image of the blood vessels is called an ''angiograph'', or more commonly an ''angiogram''. Though the word can describe both an arteriogram and a venogram, in everyday usage the terms angiogram and arteriogram are often used synonymously, whereas the term venogram is used more precisely. The term angiography has been applied to radionuclide angiography and newer vascular imaging techniques such as CO2 angiography, CT angiography and MR angiography. The term ''isotope a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coronary Circulation
Coronary circulation is the circulation of blood in the blood vessels that supply the heart muscle (myocardium). Coronary arteries supply oxygenated blood to the heart muscle. Cardiac veins then drain away the blood after it has been deoxygenated. Because the rest of the body, and most especially the brain, needs a steady supply of oxygenated blood that is free of all but the slightest interruptions, the heart is required to function continuously. Therefore its circulation is of major importance not only to its own tissues but to the entire body and even the level of consciousness of the brain from moment to moment. Interruptions of coronary circulation quickly cause heart attacks (myocardial infarctions), in which the heart muscle is damaged by oxygen starvation. Such interruptions are usually caused by coronary ischemia linked to coronary artery disease, and sometimes to embolism from other causes like obstruction in blood flow through vessels. Structure Coronary arteri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. Oxygen is Earth's most abundant element, and after hydrogen and helium, it is the third-most abundant element in the universe. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula . Diatomic oxygen gas currently constitutes 20.95% of the Earth's atmosphere, though this has changed considerably over long periods of time. Oxygen makes up almost half of the Earth's crust in the form of oxides.Atkins, P.; Jones, L.; Laverman, L. (2016).''Chemical Principles'', 7th edition. Freeman. Many major classes of organic molecules in living organisms contain oxygen atoms, such as proteins, nucleic acids, carbohydrates, and fats, as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vasodilation
Vasodilation is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. The process is the opposite of vasoconstriction, which is the narrowing of blood vessels. When blood vessels dilate, the flow of blood is increased due to a decrease in vascular resistance and increase in cardiac output. Therefore, dilation of arterial blood vessels (mainly the arterioles) decreases blood pressure. The response may be intrinsic (due to local processes in the surrounding tissue) or extrinsic (due to hormones or the nervous system). In addition, the response may be localized to a specific organ (depending on the metabolic needs of a particular tissue, as during strenuous exercise), or it may be systemic (seen throughout the entire systemic circulation). Endogenous substances and drugs that cause vasodilation are termed vasodilators. Such vasoactivity is necessary for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitroglycerine
Nitroglycerin (NG), (alternative spelling of nitroglycerine) also known as trinitroglycerin (TNG), nitro, glyceryl trinitrate (GTN), or 1,2,3-trinitroxypropane, is a dense, colorless, oily, explosive liquid most commonly produced by nitrating glycerol with white fuming nitric acid under conditions appropriate to the formation of the nitric acid ester. Chemically, the substance is an organic nitrate compound rather than a nitro compound, but the traditional name is retained. Invented in 1847 by Ascanio Sobrero, nitroglycerin has been used ever since as an active ingredient in the manufacture of explosives, namely dynamite, and as such it is employed in the construction, demolition, and mining industries. Since the 1880s, it has been used by militaries as an active ingredient and gelatinizer for nitrocellulose in some solid propellants such as cordite and ballistite. It is a major component in double-based smokeless propellants used by reloaders. Combined with nitrocellulo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
