Urine reducing substances

Increased anion gap Positive urine reducing substance Neutropenia Megaloblastic changes Low B12 and folate levels Coagulopathy... 

The presence of a-methyldopa and its metabolites in the urine reduces the diagnostic value of urinary catecholamine measurements as an indicator of pheochro-mocytoma, since these substances interfere with the fluorescence assay for catecholamines. 

S.Volatile reducing substances (including alcohols and aldehydes)—dichromate test. Carry out the method described for urine, above. 

Many reducing substances other than sugars may be found in urine (Box 25-6). Ascorbic acid (vitamin C) may be ingested in large quantities or may be present in antibiotic preparations administered intravenously. In either case, excess concentrations usually appear in the urine and contribute significantly to the total reducing substances present. 

Horrocks RH, Manning GB. Partition chromatography on paper Identification of reducing substances in urine. Lancet 1949 1 1042-5. 

Alimentary pentosuria may follow ingestion of large quantities of fruit, with L-arabinose and L-xylose occurring in high concentrations in urine. Ribosuria may occur in some muscular dystrophy patients. In both conditions, urine is positive for reducing substances. 

I 76. A newborn begins vomiting after feeding, becomes severely jaundiced, and has liver disease. Treatment for possible sepsis is initiated, and the urine is found to have reducing substances. A blood screen for galactosemia is positive, and lactose-containing substances are removed from the diet. Lactose is toxic in this case because... 

Hydrogen peroxide detection in enzyme electrodes for urine glucose assay is subject to severe interference by reducing substances, the more... 

Besides chemical methods for estimation of homogentisic acid (N9), chromatographic techniques have been described for the study of the reducing substances present in the urine of such patients (FI). 

Urines of normal and of diabetic individuals have been examined by infrared spectroscopy for analysis of the components therein, for example, reducing substances such as sugars. In conjunction with other techniques, infrared spectra can be used to examine the urine of patients with phenylketonuria. Also, the serums of blisters formed during certain diseases have been analyzed for proteia Thus, various metabolic products can be identified. 

Table A.4, Reducing substances (urine). This test> also known as Clinitest (Ames Co,), detects various reducing substances in urine by forming color complexes (green to orange)...

A test for the presence of reducing substances in urine. Benedict s reagent contains cupric ion complexed with citrate in alkaline solution. Glucose or other reducing substances reduce cupric ion to cuprous ion, resulting in the formation of yellow cuprous hydroxide or red cuprous oxide depending on the amount of reducing substance present. 

A tablet test, manufactured by the Ames company for the detection of reducing substances in urine. It is based on the Benedict reaction. 

A metabolite of salicylate, being a conjugate of this compound and glycine. It can be detected as a reducing substance in urine, following ingestion of salicylates... 

Phenols can be estimated directly on urine if interfering reducing substances such as uric acid are first removed (44, 45). The authors find it more convenient to separate the phenols by ether extraction or by steam distillation and then to apply the Folin-Ciocalteu reagent (27). 

When dimethyl-p-toluidine is fed to rabbits a reducing substance is excreted which probably is p-dimethylaminobenzoyl glucuronoside, for p-dimethylaminobenzoic acid can be isolated from the urine (162). If the urine is hydrolyzed with acid and distilled, o-dimethylaminophenol is produced this is probably derived from p-dimethylamino- re-hydroxybenzoic acid (164). 

Yeast Fermentation Teat.—The method is described on p, 114. Lactose, pentoses and glycuronic acid are the only non-fermentable copper-reducing substances likely to occur in urine, and the fermentation test should be used to check the tests of Benedict and Eehling. 

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