Juan Gabriel March

Learn More
Phosphates precipitating from artificial urine in the pH range 6-8 were identified using X-ray diffraction, chemical analysis and scanning electron microscopy. The influence of magnesium and citrate on phases precipitating from urine was established. From urine containing a normal quantity of magnesium (around 70 ppm), brushite accompanied by hydroxyapatite(More)
A GC-MS method is reported for the determination of phytic acid based on purification by anion-exchange chromatography, enzymatic hydrolysis of phytic acid to myo-inositol and derivation to trimethylsilyl derivative, with scyllo-inositol as an internal standard. Analytical features of the method are: limit of detection 9 microg l(-1) phytic acid, linear(More)
The AIN-76 A, a purified rodent diet, has a propensity to cause kidney calcifications in female rats which is not observed with non-purified rodent diets, suggesting a nutritional factor that avoids these calcifications. One candidate is phytate, which inhibits crystallisation of calcium salts and is practically absent in purified diets. Therefore, the(More)
Phytate (inositol hexaphosphate; InsP6) was determined in rat tissues fed on diets with different phytate contents, using a GC-mass detection methodology that permitted the evaluation of the total amount of this substance present in such tissues. The highest InsP6 concentrations were found in brain 5.89 x 10(-2)(SE 5.7 x 10(-3)) mg/g DM), whereas the(More)
OBJECTIVE To study the relationship between the oral intake of inositol hexakisphosphate (InsP6, phytic acid, an inhibitor of urinary crystallization) and its urinary excretion, to establish their possible mutual influence. MATERIALS AND METHODS Two groups of male Wistar rats (six animals each) received either; tap water and normal rat food pellets(More)
A study of the pharmacokinetic profile (oral absorption and renal excretion) of inositol hexaphosphate or phytate (IP(6)) is presented. Seven healthy volunteers were following a IP(6) poor diet (IP(6)PD) in a first period, and on IP(6) normal diet (IP(6)ND) in a second one. When following the IP(6)PD they become deficient in IP(6), the basal levels found in(More)
The phytate urinary levels in a group of active calcium oxalate stone formers were studied and compared with those found in healthy people. Urinary phytate was significantly lower for stone formers. If deficit of the capacity to inhibit crystallization of calcium salts is considered an important factor related to calcium stone formation, the excretion of(More)
The relation between the dietary phytate (InsP6), mineral status and InsP6 levels in the organism, using three controlled diets (AIN-76A, AIN-76A + 1% phytate, AIN-76A + 6% carob seed germ), are studied. AIN-76A is a purified diet in which InsP6 is practically absent. No important or significant differences in the mineral status (Zn, Cu, Fe) of blood,(More)
An enzymatic method for the determination of pyrophosphate which has been applied to renal calculi is described. The method involves the preconcentration of pyrophosphate using anionic exchange resin and development of the enzymatic reactions with the pyrophosphate retained on the resin. The study of calculi treatment according to calculi composition is(More)
The determination of chlorine with o-tolidine in greywater has been studied, and a batch method and a sequential injection method have been proposed. It was found that the reaction of o-tolidine with chlorine was slower in a greywater matrix. Grey water samples must be filtered before analysis, or alternatively, a blank of sample must be measured. The(More)