Physiology and pathology of the urine : with methods for its examination / by J. Dixon Mann.

  • John Dixon Mann
Date:
1904
Catalogue details

Licence: In copyright

Credit: Physiology and pathology of the urine : with methods for its examination / by J. Dixon Mann. Source: Wellcome Collection.

    84/292 page 68
    GLYCURONIC ACID. 0^11,„0,. This monobasic acid is closely related to glucose, from which it may be obtained by oxidation. It belongs to the group of aldehydes, and therefore acts as a reducing-agent. It reduces ammonio-nitrate of silver in the cold, and alkaline solutions of cupric and bismuthic oxides with the aid of heat. It forms a crystalline compound with phenylhydrazin, and, like the pentoses to which it is also closely related, it does not undergo alcoholic fermentation. It conjugates with phenol, indoxyl, and skatoxyl, and in normal urine chiefly occurs as phenolglycuronic acid in combination with potassium. Free glycuronic acid is cZexiro-rotatory, but, almost without exception, t s combinations are Zcew-rotatory. Many observers have noticed that almost all normal urines have a feeble laevo-rotatory power, and that they also possess slight reducing properties, both of which are doubtless due to the presence of glycuronic acid combinations. In small amount glycuronic acid occurs in normal urine. Mayer and Neuberg’ demonstrated its presence to the extent of 4 mgi-ms. in 100 c.c. of urine; it was found to exist chiefly in conjugation with phenol, and, in a lesser degree, with indoxyl and skatoxyl. Mayer® believes, in many cases, that the power of the organism to oxidise glucose is so far diminished that, in part, the oxidation stops short at the formation of glycuronic acid. He found, after giving from 100 to 200 grms. of grape-sugar to patients with alimentary glycosuria, that in fourteen instances conjugated glycuronic acid along with sugar, and in six the conjugated acid without sugar, appeared in the urine. In various acute febrile diseases, and also in conditions associated with respiratory difficulty, a like increase of conjugated glycuronic acid was found. Mayer gave 10 grms. of sodium glycuronate to a rabbit, which caused both saccharic acid and a large quantity of oxalic acid to appear in the urine. He explains the occurrence of oxaluria in diabetes mellitus on the assumption that tlie excessive exci'etion of sugar is due to most of it not undergoing any oxidation at all; whilst by better sugar-assimilation part is oxidised, not to carbon dioxide and water, but only to oxalic acid. Blumenthal ® finds it difficult to understand how small amounts of glucose and of glycuronic acid can be excreted together solely because the oxidising power for these substances is diminished. He thinks that since unconjugated glycuronic acid is never present in urines, even after it has been hypodermically injected, it is probable that the formation of the substances with which it conjugates may 1 ZfiitHchr.f. phyMol. Ch.cm., 1900. 2 Deutsche mcil. ]i ache use hr., 1901.
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