Water, fat, nitrogen, and sugar content in feces: reference intervals in children.

Malabsorption-maldigestion syndromes are commonly found in several gastrointestinal diseases. Quantitative measures of fecal nutrients are important tools for the detection and diagnosis of these syndromes. Adequate food intake is important in the nutrition of children, especially during the first year of life. We have analyzed 180 stools of healthy children, divided into four age groups, to obtain the reference intervals of the major nutrients such as water, fat, nitrogen, sugar, and starch. Quantification of the nutrients was done by means of a near-infrared analyzer (Fenir 8820). Results show that this instrument exhibits a low coefficient of variation for all the nutrients except for starch. Fecal water, fat, nitrogen, and sugar concentrations ranged from 68.7 to 96.1 g/100 g, 0 to 14.5 g/100 g, 1.3 to 2.3 g/100 g, and 0.7 to 3.8 g/100 g, respectively. The results for the starch analyses were not acceptable because of instrument limitations. Near-infrared reflectance spectroscopy appears to be an alternative to standard chemical methods.

[Deoxypyridinoline and other biochemical markers of bone resorption in distinct pathologies]. / Deoxipiridinolina y otros marcadores bioquímicos de reabsorción ósea en distintas patologías.

Collagen type 1 represents more than 90% of bone matrix. Therefore, quantitation of collagen crosslinks, such as deoxypyridinoline, can provide information on bone resorption degree. An evaluation was made of deoxypyridinoline as well as other bone markets, such as alkaline phosphatase, tartrate resistant acid phosphatase, and hydroxyproline in patients with the diagnosis of osteoporosis. Paget's disease, hyperthyroidism, and chronic renal failure on haemodialysis or not. Deoxypyridinoline levels were significantly increased in patients with osteoporosis, Paget's disease, and hyperthyroidism. Hydroxyproline levels were increased in patients with Paget's disease, and tartrate resistant acid phosphatase was increased in all the entities studied. Deoxypyridinoline can be a more sensitive marker than hydroxyproline, with some advantages, such as its quantitation in a urine specimen and its high bone specificity. In patients with renal failure, tartrate resistant acid phosphatase was the only biochemical marker of bone resorption with increased levels.

Effect of the pH and the importance of the internal standard on the measurement of the urinary catecholamines by high-performance liquid chromatography.

Clinical manifestations of phaeochromocytoma are not always sufficient for its early diagnosis. It is therefore necessary to confirm hypersecretion of catecholamines. Current methods for the measurement of catecholamines are based on their oxidative properties, and the majority of the laboratories often use HPLC methods for catecholamine testing. However, the extraction procedures used for the biogenic amines differ. We use a method of ion-exchange chromatography which is performed at pH 6.5. In order to avoid the spontaneous oxidation of the catecholamines, the urine samples has to be collected on HCl, which gives a pH of approximately 2. Occasionally, the acidified urine sample has a pH less than 1 requiring the addition of NaOH to reach a pH of 6.5, necessary for the adsorption of catecholamines on cation exchanger resins. This phenomenon produces a decrease in the peak areas but the use of an internal standard allows the final results to be corrected.