Serum monoamine oxidase (MAO)

Monoamine oxidase (MAO), an enzyme that catalyzes the oxidative deamination of monoamines, acts on primary amines and their methylated secondary and tertiary amines, and also on long-chain diamines. It also has a role in the so-called biogenic amines, namely tyramine, catecholamine, serotonin, norepinephrine, adrenaline and the like. This enzyme is more common in various organs of vertebrates, especially secretory glands, brain, and liver, but also in plants such as invertebrates and buds of legumes. In the cell, the outer membrane of the mitochondria is an insoluble enzyme. Contains FAD. Drugs such as iproniazid and β-phenylisopropyl pheniprazine have a strong competitive inhibitory effect on this enzyme, called MAO inhibitors, but For animals, the concentration of monoamines such as norepinephrine and serotonin in the brain can be increased, causing stimulation of action. Therefore, monoamine oxidase is considered to have a function of regulating the concentration of amine in the living body. MAO has MAO-I, MAO-II and MAO-III. The increase of serum MAO-I activity is common in organ fibrosis, especially cirrhosis and acromegaly. The increase of serum MAO-II activity is common in large areas. Liver necrosis is an important indicator for the diagnosis of cirrhosis. Basic Information Specialist classification: growth and development check classification: biochemical examination Applicable gender: whether men and women apply fasting: fasting Analysis results: Below normal: Found in burn patients. Normal value: Adult: 12-40U/ml Above normal: Increased serum MAO-I activity is mainly seen in cirrhosis and acromegaly; while elevated MAO-II is mainly seen in large areas of hepatic necrosis. negative: Positive: Tips: Do not eat too greasy, high-protein foods the day before the blood draw, avoid heavy drinking. After 8 pm on the day before the medical examination, you should start fasting for 12 hours to avoid affecting the test results. Normal value Healthy adult serum MAO activity is 12-40 U/ml. (Note the specific reference value depends on each laboratory.) Clinical significance MAO is an enzyme widely distributed in the liver, kidney, stomach, small intestine and brain tissue, and is localized in the cell outside the mitochondrial membrane. Determination of serum MAO activity is an important indicator for the examination of liver fibrosis. When fibrosis occurs between the portal area or between the central areas of the manifold, the MAO activity is significantly increased, and the positive rate is above 80%. When there is extensive fibrosis around the pseudo-lobule, it is almost all increased, and the increase is the largest. . When the fibrotic lesions invade the liver parenchyma, the rate of increase is only 30%. 1. Raise Increased serum MAO-I activity is mainly seen in cirrhosis and acromegaly; while elevated MAO-II is mainly seen in large areas of hepatic necrosis. Increased serum MAO activity in patients with organ fibrosis is associated with increased metabolism of connective tissue; elevated serum MAO activity in patients with fulminant hepatitis is associated with MAO detachment from necrotic hepatocyte mitochondria. Therefore, in the case of fulminant hepatitis and severe hepatocyte necrosis, the mitochondrial MAO is released, and the activity of the enzyme in the serum is increased, and the positive rate is over 73%. 2, lower Found in burns. High results may be diseases: viral hepatitis, cirrhosis, acromegaly considerations First, the precautions before blood draw 1, do not eat too greasy, high-protein food the day before the blood, to avoid heavy drinking. The alcohol content in the blood directly affects the test results. 2. After 8 pm on the day before the medical examination, you should start fasting for 12 hours to avoid affecting the test results. 3, should relax when taking blood, to avoid the contraction of blood vessels caused by fear, increase the difficulty of blood collection. Second, should pay attention after blood draw 1. After blood is drawn, local compression is required at the pinhole for 3-5 minutes to stop bleeding. Note: Do not rub, so as not to cause subcutaneous hematoma. 2, the pressing time should be sufficient. There is a difference in clotting time for each person, and some people need a little longer to clotting. Therefore, when the surface of the skin appears to be bleeding, the compression is stopped immediately, and the blood may be infiltrated into the skin due to incomplete hemostasis. Therefore, the compression time is longer to completely stop bleeding. If there is a tendency to bleed, the compression time should be extended. 3, after the blood draw symptoms of fainting such as: dizziness, vertigo, fatigue, etc. should immediately lie down, drink a small amount of syrup, and then undergo a physical examination after the symptoms are relieved. 4. If there is localized congestion, use a warm towel after 24 hours to promote absorption. Third, the medical staff pay attention to the inspection 1. Ensure the reliability of the results, and pay attention to prevent hemolysis, the specimens are fresh. 2. If the test result is inconsistent with the clinical, repeat or trace the test if necessary. Inspection process Immediately after venous blood collection, the test method was determined by polyacrylamide gel electrophoresis. Not suitable for the crowd no. Adverse reactions and risks no.