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Captopril Challenge Test
__NOTOC__ The captopril challenge test (CCT) is a non-invasive medical test that measures the change in renin plasma-levels in response to administration of captopril, an angiotensin converting enzyme inhibitor. It is used to assist in the diagnosis of renal artery stenosis. It is not generally considered a useful test for children, and more suitable options are available for adult cases. Procedure Plasma concentration of renin is measured prior to and following the administration of captopril. The CCT is considered positive if the renin levels increase substantially or the baseline renin level is abnormally high. An abnormal captopril test is indicative of the presence of renovascular disease. In adults CCT in adults is known to have high sensitivity, but a low specificity. Subtraction angiography is considered a more suitable test for renal artery stenosis in adults.Svetkey LP, Himmelstein SI, Dunnick NR, Wilkinson RH Jr, Bollinger RR, McCann RL, Beytas EM, Klotman PE. Prospec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Captopril
Captopril, sold under the brand name Capoten among others, is an ACE inhibitor, angiotensin-converting enzyme (ACE) inhibitor used for the treatment of hypertension and some types of congestive heart failure. Captopril was the first oral ACE inhibitor found for the treatment of hypertension. It does not cause fatigue as associated with beta-blockers. Due to the adverse drug event of causing hyperkalemia, as seen with most ACE Inhibitors, the medication is usually paired with a diuretic. Captopril was patented in 1976 and approved for medical use in 1980. Structure–activity relationship Captopril has an L-proline group which allows for it to be more bioavailable within oral formulations. The thiol moiety within the molecule has been associated with two significance adverse effects: the hapten or immune response. This immune response, also known as agranulocytosis, can explain the adverse drug events which may be seen in captopril with the allergic response, which would be: hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Renin
Renin (etymology and pronunciation), also known as an angiotensinogenase, is an aspartic protease protein and enzyme secreted by the kidneys that participates in the body's renin–angiotensin–aldosterone system (RAAS)—also known as the renin–angiotensin–aldosterone axis—that increases the volume of extracellular fluid (blood plasma, lymph and interstitial fluid) and causes arterial vasoconstriction. Thus, it increases the body's mean arterial blood pressure. Renin is not commonly referred to as a hormone, albeit it having a receptor, the (pro)renin receptor, also known as the renin receptor and prorenin receptor (see also below), as well as enzymatic activity with which it hydrolyzes angiotensinogen to angiotensin I. Biochemistry and physiology Structure The primary structure of renin precursor consists of 406 amino acids with a pre- and a pro-segment carrying 20 and 46 amino acids, respectively. Mature renin contains 340 amino acids and has a mass of 37 kDa. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood Plasma
Blood plasma is a light amber-colored liquid component of blood in which blood cells are absent, but contains proteins and other constituents of whole blood in suspension. It makes up about 55% of the body's total blood volume. It is the intravascular part of extracellular fluid (all body fluid outside cells). It is mostly water (up to 95% by volume), and contains important dissolved proteins (6–8%; e.g., serum albumins, globulins, and fibrinogen), glucose, clotting factors, electrolytes (, , , , , etc.), hormones, carbon dioxide (plasma being the main medium for excretory product transportation), and oxygen. It plays a vital role in an intravascular osmotic effect that keeps electrolyte concentration balanced and protects the body from infection and other blood-related disorders. Blood plasma is separated from the blood by spinning a vessel of fresh blood containing an anticoagulant in a centrifuge until the blood cells fall to the bottom of the tube. The blood plasma is t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Captopril
Captopril, sold under the brand name Capoten among others, is an ACE inhibitor, angiotensin-converting enzyme (ACE) inhibitor used for the treatment of hypertension and some types of congestive heart failure. Captopril was the first oral ACE inhibitor found for the treatment of hypertension. It does not cause fatigue as associated with beta-blockers. Due to the adverse drug event of causing hyperkalemia, as seen with most ACE Inhibitors, the medication is usually paired with a diuretic. Captopril was patented in 1976 and approved for medical use in 1980. Structure–activity relationship Captopril has an L-proline group which allows for it to be more bioavailable within oral formulations. The thiol moiety within the molecule has been associated with two significance adverse effects: the hapten or immune response. This immune response, also known as agranulocytosis, can explain the adverse drug events which may be seen in captopril with the allergic response, which would be: hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angiotensin Converting Enzyme Inhibitor
Angiotensin-converting-enzyme inhibitors (ACE inhibitors) are a class of medication used primarily for the treatment of high blood pressure and heart failure. They work by causing relaxation of blood vessels as well as a decrease in blood volume, which leads to lower blood pressure and decreased oxygen demand from the heart. ACE inhibitors inhibit the activity of angiotensin-converting enzyme, an important component of the renin–angiotensin system which converts angiotensin I to angiotensin II, and hydrolyses bradykinin. Therefore, ACE inhibitors decrease the formation of angiotensin II, a vasoconstrictor, and increase the level of bradykinin, a peptide vasodilator. This combination is synergistic in lowering blood pressure. As a result of inhibiting the ACE enzyme in the bradykinin system, the ACE inhibitor drugs allow for increased levels of bradykinin which would normally be degraded. Bradykinin produces prostaglandin. This mechanism can explain the two most common ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Renal Artery Stenosis
Renal artery stenosis (RAS) is the narrowing of one or both of the renal arteries, most often caused by atherosclerosis or fibromuscular dysplasia. This narrowing of the renal artery can impede blood flow to the target kidney, resulting in renovascular hypertension – a secondary type of high blood pressure. Possible complications of renal artery stenosis are chronic kidney disease and coronary artery disease. Signs and symptoms Most cases of renal artery stenosis are asymptomatic, and the main problem is high blood pressure that cannot be controlled with medication. Decreased kidney function may develop if both kidneys do not receive adequate blood flow, furthermore some people with renal artery stenosis present with episodes of flash pulmonary edema. Cause Renal artery stenosis is most often caused by atherosclerosis which causes the renal arteries to harden and narrow due to the build-up of plaque. This is known as atherosclerotic renovascular disease, which accounts for abo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensitivity (tests)
''Sensitivity'' and ''specificity'' mathematically describe the accuracy of a test which reports the presence or absence of a condition. Individuals for which the condition is satisfied are considered "positive" and those for which it is not are considered "negative". *Sensitivity (true positive rate) refers to the probability of a positive test, conditioned on truly being positive. *Specificity (true negative rate) refers to the probability of a negative test, conditioned on truly being negative. If the true condition can not be known, a " gold standard test" is assumed to be correct. In a diagnostic test, sensitivity is a measure of how well a test can identify true positives and specificity is a measure of how well a test can identify true negatives. For all testing, both diagnostic and screening, there is usually a trade-off between sensitivity and specificity, such that higher sensitivities will mean lower specificities and vice versa. If the goal is to return the ratio at w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Specificity (tests)
''Sensitivity'' and ''specificity'' mathematically describe the accuracy of a test which reports the presence or absence of a condition. Individuals for which the condition is satisfied are considered "positive" and those for which it is not are considered "negative". *Sensitivity (true positive rate) refers to the probability of a positive test, conditioned on truly being positive. *Specificity (true negative rate) refers to the probability of a negative test, conditioned on truly being negative. If the true condition can not be known, a " gold standard test" is assumed to be correct. In a diagnostic test, sensitivity is a measure of how well a test can identify true positives and specificity is a measure of how well a test can identify true negatives. For all testing, both diagnostic and screening, there is usually a trade-off between sensitivity and specificity, such that higher sensitivities will mean lower specificities and vice versa. If the goal is to return the ratio at w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subtraction 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Captopril Suppression Test
The captopril suppression test (CST) is a non-invasive medical test that measures plasma levels of aldosterone Aldosterone is the main mineralocorticoid steroid hormone produced by the zona glomerulosa of the adrenal cortex in the adrenal gland. It is essential for sodium conservation in the kidney, salivary glands, sweat glands, and colon. It plays a c .... Aldosterone production is suppressed by captopril through the renin–angiotensin–aldosterone system. CST results are used to assist in the diagnososis of primary aldosteronism (Conn Syndrome). See also * Captopril challenge test - used to diagnose renal artery stenosis References Blood tests Dynamic endocrine function tests {{Med-diagnostic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primary Aldosteronism
Primary aldosteronism (PA)'','' also known as primary hyperaldosteronism or Conn's syndrome, refers to the excess production of the hormone aldosterone from the adrenal glands, resulting in low renin levels and high blood pressure. This abnormality is caused by hyperplasia or tumors. Many experience fatigue, potassium deficiency and high blood pressure which may cause poor vision, confusion or headaches. Symptoms may also include: muscular aches and weakness, muscle spasms, low back and flank pain from the kidneys, trembling, tingling sensations, dizziness/vertigo, nocturia and excessive urination. Complications include cardiovascular disease such as stroke, myocardial infarction, kidney failure and abnormal heart rhythms. Primary hyperaldosteronism has a number of causes. About 33% of cases are due to an adrenal adenoma that produces aldosterone, and 66% of cases are due to an enlargement of both adrenal glands. Other uncommon causes include adrenal cancer and an inherited d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood Tests
A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a hypodermic needle, or via fingerprick. Multiple tests for specific blood components, such as a glucose test or a cholesterol test, are often grouped together into one test panel called a blood panel or blood work. Blood tests are often used in health care to determine physiological and biochemical states, such as disease, mineral content, pharmaceutical drug effectiveness, and organ function. Typical clinical blood panels include a basic metabolic panel or a complete blood count. Blood tests are also used in drug tests to detect drug abuse. Extraction A venipuncture is useful as it is a minimally invasive way to obtain cells and extracellular fluid (plasma) from the body for analysis. Blood flows throughout the body, acting as a medium that provides oxygen and nutrients to tissues and carries waste products back to the excretory systems for disposal. Conseq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
