Niacin

Niacin is also known as vitamin B3, or vitamin PP. It is one of the 13 kinds of vitamins necessary for the human body. It is a water-soluble vitamin and belongs to the vitamin B family. Niacin is mainly present in foods in the form of coenzymes and is absorbed in the stomach and small intestine after digestion. After absorption, it enters the liver through the portal vein in the form of niacin. Excess niacin is mostly excreted from the urine via methylation. Niacin is converted into nicotinamide in human body. Niacinamide is a component of coenzyme I and coenzyme II, which participates in lipid metabolism in the body, oxidation process of tissue respiration and anaerobic decomposition of carbohydrates. The lack of symptoms is (癞) pellagra, and its symptoms are characterized by three dermatitis, diarrhea, and dementia. Black tongue disease can occur in dogs. Basic Information Specialist classification: growth and development check classification: biochemical examination Applicable gender: whether men and women apply fasting: fasting Reminder: Laboratory tests can only be used under certain conditions. It is unreliable to determine the niacin value in blood. The amount of niacin metabolite N\'-methylnicotinamide excreted in 24 hours of urine (calculated per gram of creatinine) was determined, which is currently considered to be the most effective test for determining the nutritional status of niacin in the body. Normal value 1, 65 ~ 130μmol / l (8 ~ 16μg / ml). 2, load test: normal human two metabolite reference value of 7.0 ~ 37.0mg, when <3.0mg is the body niacin deficiency. 3. Nitrogen N'-methylnicotinamide excretion: Clinical significance 1. Elevation: When niacin or its inducer is used. 2, lower: pellagra, a potential niacin deficiency state. Low results may be diseases: niacin deficiency, niacin deficiency neurological precautions Laboratory tests can only be used under conditions, and determination of niacin in blood is unreliable. So far, the amount of N'-methylnicotinamide excretion of niacin in 24h urine (calculated per gram of creatinine) has been determined, which is currently considered to be the most effective test for determining the nutritional status of niacin in vivo. Clinical symptoms have declined before they appear and have clinical value. Inspection process Detection method: 1. Determination of N'-methylnicotinamide emission in urine: Since N'-methylnicotinamide in urine is a metabolite of nicotinic acid, the measurement of urinary metabolites can indirectly reflect the level of niacin in the body. N'-methylnicotinamide does not fluoresce, condenses with acetone to synthesize a derivative with yellow fluorescence in an alkaline environment, and then heats in an acidic solution to form a naphthyridine compound which exhibits strong blue fluorescence under 365 nm light. Its fluorescence intensity is proportional to the N'-methylnicotinamide content. 2. Load test: After urinating in the morning, the standard diet containing 10 mg of nicotinic acid and 100 mg of tryptophan, then collecting urine for 24 hours, and measuring N'-methylnicotinamide and N'-methyl in urine 2-pyridone content. Detection process: 1. Purification: Take 10 ml stoppered test tubes and indicate the measuring tube (U) and standard tube (S). 2 ml of urine and 0.2 ml of glacial acetic acid were added to the tube, and diluted to 10 ml with water. A standard solution of 10 ml of N'methylnicotinamide was added to the standard tube. Add 100 mg of activated carbon to each of the two tubes, mix them several times, immediately filter with filter paper, and take the filtrate for determination. 2. Reaction: Take 10 tubes of 10 ml stoppered tubes, indicate the measuring tube (U), and measure blank tube (UB), standard tube (S) and standard blank tube (SB). 3, fluorescence measurement: first use the quinine sulfate application solution to read the reading to 50 ~ 80. The excitation wavelength is 330-360 nm, the emission wavelength is 430-450 nm, and the fluorescence intensity of each tube is read. Not suitable for the crowd Inappropriate people: Generally there are no people who are not suitable. Adverse reactions and risks 1. Infection: Pay attention to aseptic operation when collecting blood, avoid contamination of water and other parts at the blood collection site to avoid local infection. 2, bleeding: after the blood is given a full compression time, especially coagulopathy, bleeding tendency, to avoid local subcutaneous oozing, bruising and swelling.