Urine normal

MAMMALS, TERRESTRIAL Animal tissues, blood, urine Normal Usually <10 FW 19... 

In addition to the examples discussed above, a number of other xenobiotics are measured by their phase I reaction products. These compounds and their metabolites are listed in Table 20.1. These methods are for metabolites in urine. Normally, the urine sample is acidified to release the phase I metabolites from phase II conjugates that they might have formed, and except where direct sample injection is employed, the analyte is collected as vapor or extracted into an organic solvent. In some cases, the analyte is reacted with a reagent that produces a volatile derivative that is readily separated and detected by gas chromatography. 

Phenylpyruvate is excreted in the urine. Normal urine does not contain any phenylpyruvate People suffering from PKU have varying amounts of phenylpyruvate in their urine. PKU causes severe mental retardation in infants if it is not treated immediately after birth, which is done by restricting the phenylalanine content of the diet. In many states, the law requires that every newborn be tested for phenylpyruvate in the urine. The test is based on the reaction of the iron (III) ion with the phenylpyruvate, producing a gray-green color. 

Focusing our attention on the serotonin branch of Figure 20.21, it is seen that the initial hydroxylation reaction requires tetrahydrobiopterin, which was introduced in Chapter 16 and is discussed further here. Serotonin per se is a neurotransmitter, and it can give rise to melatonin in the pineal gland. Melatonin is synthesized at night, and is believed to be associated with the phenomenon of circadian rhythms. Serotonin is metabolized to 5-hydroxyindoleacetic acid, which is excreted in the urine. Normal 5-hydroxyindoleacetic add excretion is about 7 mg/day, whereas in carcinoid tumor patients, this may be as high as 400 mg/day. Carcinoid is an intestinal tumor that may metastasize into the liver. 

Amino acids (AA) have also been studied on microdevices for development of microclinical analysis devices. In urine, normal ranges for standard amino acids and their metabolites range from 0 to 24 mM, with abnormal concentrations indicative of a number of disease states. Plasma concentrations of certain amino acids can also be used for disease detection. Elevated homocysteine levels in plasma is an independent risk factor for cardiovascular disease. Microdevices employing end-column amperometric detection were used for the determination... 

Use in diagnosis dexamethasone suppression test. Dexamethasone acts on the h5q othalamus (like hydrocortisone), to reduce output of corticotropin releasing hormone (CRH), but it does not interfere with measurement of corticosteroids in blood or urine. Normal suppression of cortisol production after administering dexamethasone indicates that the hypothalamic/pituitary/adrenal axis is intact. Failure of suppression implies pathological hypersecretion of ACTH by the pituitary or of cortisol by the adrenal. Dexamethasone is used because its action is prolonged (24 h). There are several ways of carrying out the test. 

The sensitivity of values determined 2 hours after food consumption seems to be higher than that after fasting. The fasting value is, however, preferred for the sake of reproducibility. In liver diseases, the postprandial increase in serum values can be several times higher than after fasting. In healthy individuals, however, fasting values are only exceeded by 50-70%. The elevation of bile acids in the serum is reflected by an increase in their excretion in the urine (normal < 8 gmol/day). The elevated level of bile acids returns to normal at a relatively slow pace. 

Oxalic acid is poorly absorbed with a bioavailability of 2-5%. It is excreted unchanged in the urine. Normal urinary oxalic acid excretion ranges from 8 to 40 mg day... 

Test results are affected by defective intestinal absorption caused by intestinal disease or variations in transit time, by impaired hepatic conjugation caused by liver disease, and by impaired renal excretion. To compensate for these possible errors, a control substance (e.g., PABA) may be given on a second day, or alternatively, C-PABA or p-aminosalicylic acid (PAS) can be given orally with the NBT-PABA. Low recovery of the control substance in the urine indicates probable decreased intestinal absorption or decreased renal excretion. About 60% (range 48% to 72%) of the orally administered dose is recovered in the urine normally. In pancreatic insufficiency, PABA excretion is significantly decreased. The result is then calculated as a pancreatic excretion index (PEI) as follows ... 

Urobilinogen is excreted mostly in the feces, but a small fraction is absorbed from the colon, enters the portal circulation, is removed by the liver, and is secreted into bile. That which is not removed from the portal blood by the liver enters the systemic circulation and is excreted by the kidneys. Urobilinogen excretion in urine normally amounts to 1-4 mg per 24 hours, as opposed to the 40-280 mg (67 70 /umol) excreted in feces. 

Spreux-Varoquaux, O. Chapalain, J.P. Cordonnier, P. Advenier, C. Pays, M. Lamine, L. Determination of trimethoprim, sulfamethoxazole and its N4-acetyl metabolite in biological fluids by high-performance liquid chromatography. J.Chromatogr., 1983, 274, 187-199 [LOD 15 ng/mL plasma urine normal phase gradient simultaneous theophylline non-interfering caffeine pharmacokinetics]... 

Freeze dried Urine (normal and elevated level) NIST-SRM-2672a Hg/Hg... 

Using high-pressure liquid chromatography (HPLC), it is possible to show that patients with this variant of hyperphenylalaninemia excrete only oxidized forms of biopterin in their urine normal children and those with phenylalanine hydroxylase deficiency excrete predominantly tetrahydrobiopterin. 

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