homogentisic acid การใช้

• It is derived from the oxidative dimerization of homogentisic acid.
• The defect was narrowed down to homogentisic acid oxidase deficiency in a study published in 1958.
• "' Ochronosis "'is a syndrome caused by the accumulation of homogentisic acid in connective tissues.
• Additionally, 4-HPPA can be converted to homogentisic acid which is one of the precursors to ochronotic pigment.
• It has been demonstrated that treatment with nitisinone can reduce urinary levels of homogentisic acid in alkaptonuria patients by 95 %.
• Recently the drug nitisinone has been found to suppress homogentisic acid production, and research is ongoing as to whether it can improve symptoms.
• The homogentisic acid is converted to the related substance benzoquinone acetic acid ( BQA ) which forms polymers that resemble the skin pigment melanin.
• Alkaptonuria is caused when an enzyme called homogentisic dioxygenase ( HGD ) is faulty so can't break down homogentisic acid ( HGA ).
• Virchow discovered the clinical syndrome which he called ochronosis, a metabolic disorder in which a patient accumulates homogentisic acid in connective tissues and which is indicated by discolouration under the microscope.
• More specifically, inhibition of HPPD prevents the formation of a breakdown product, homogentisic acid, which in turn is a key precursor for the biosynthesis of both tocopherols and plastoquinone.
• If the diagnosis of alkaptonuria is suspected, this can be confirmed or excluded by collecting urine for twenty-four hours and determining the amount of homogentisic acid by means of chromatography.
• Apart from treatment of the complications ( such as joint replacement for the cartilage damage ), vitamin C has been used to reduce the ochronosis and lowering of the homogentisic acid levels may be attempted with a low-protein diet.
• False positive reaction can be due to the presence of other reducing substances in urine such as ascorbic acid ( during intake of vitamin supplements ), drugs ( levodopa, contrast used in radiological procedures ) and homogentisic acid ( alkaptonuria ).
• Nitisinone inhibits the enzyme, 4-hydroxyphenylpyruvate dioxygenase, responsible for converting tyrosine to homogentisic acid, thereby blocking the production and accumulation of HGA . Nitisinone has been used for some time at much higher doses in the treatment of type I tyrosinemia.