31 results on '"F. Grases"'
Search Results
2. Validation of a novel diagnostic test for assessing the risk of urinary uric acid crystallization.
- Author
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Calvó P, Costa-Bauzá A, Grases F, Hernandez Y, and Sanchis P
- Subjects
- Adult, Crystallization, Diagnostic Tests, Routine, Humans, Kidney Calculi, Uric Acid
- Abstract
Background and Aims: Uric acid (UA) kidney stones account for 10 to 11% of all kidney stones, and this percentage has increased over time. An accurate, rapid, simple, and low-cost test is needed to distinguish urine that is susceptible and resistant to the formation of UA crystals. The aim of this paper is to develop a test to assess the risk for UA crystallization (RUAC) and to validate its utility in routine clinical practice by analysis of urine samples of UA stone formers and healthy volunteers., Patients and Methods: Urine samples of 20 healthy adult volunteers and 54 active formers of UA stones were collected. Three samples were collected from each participant, with at least 7 days between each collection. The main lithogenic parameters for UA stones were determined, and an RUAC test was performed in all urine samples., Results: Our RUAC test reliably discriminated urine that was resistant and susceptible to the formation of UA crystals. This test had high specificity (94%) and a low percentage of false negatives., Conclusion: The RUAC test described here had high diagnostic accuracy, low-cost, and a rapid assay time, that make this test an attractive screening tool for UA stone fomers follow-up., (Copyright © 2021 The Author(s). Published by Elsevier B.V. All rights reserved.)
- Published
- 2021
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3. Analysis of urine composition from split 24-h samples: use of 12-h overnight samples to evaluate risk factors for calcium stones in healthy and stone-forming children.
- Author
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Mir C, Rodriguez A, Rodrigo D, Saez-Torres C, Frontera G, Lumbreras J, Espinosa N, Gomez C, Costa-Bauza A, and Grases F
- Subjects
- Calcium Oxalate, Child, Citric Acid, Humans, Risk Factors, Calcium, Kidney Calculi diagnosis, Kidney Calculi epidemiology
- Abstract
Introduction: The analysis of 24-h urine is the gold standard to diagnose metabolic abnormalities in the stone-forming patient. However, urinary composition changes throughout the day and analyzing the whole 24-h urine may mask peaks of increased risk of crystallization., Objective: To examine variations of stone-promoting and stone-inhibiting factors in urine using split 24-h samples from healthy and stone-forming children., Study Design: Urine was collected from 87 healthy and 26 stone-forming children using a split collection procedure (12-h daytime urine and 12-h overnight urine). Urine volume, pH, calcium (Ca), magnesium (Mg), phosphate (P), citrate (Cit), uric acid (Ur), and oxalate (Ox) were determined, and the Ca/Cit ratio was calculated., Results: The overnight urine samples in both groups had higher levels of P and Mg, lower volume, lower pH, and less citrate and uric acid. As can be seen in the table, higher percentages of healthy and stone-forming children had altered 12-h night urine than 24-h urine with regards to Ca/Cr, Cit/Cr and Ca/Cit ratios. All healthy subjects and all stone-forming children (except one) with altered Cit/Cr ratios or Ca/Cit ratios in the 24-h sample also had altered ratios in the 12-h overnight sample., Discussion: This study indicates that urine composition changes throughout the day, and that there is daily variability in most of the parameters related to kidney stone formation. Furthermore, 12-h overnight samples seem to be more sensitive than 24-h samples in detecting the most common urinary abnormalities. The main limitation of this study is the relative low sample size of stone-forming children, owing to the low prevalence of nephrolithiasis in childhood., Conclusions: We observed a higher excretion of stone-promoting substances and a lower citrate in urine at night. However, the study results do not provide enough evidence to conclude that the use of a 12-h overnight sample collection can replace 24 h urine analysis in the metabolic evaluation of children with lithiasis., (Copyright © 2020 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2020
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4. 2,4-Diamino-N10-methylpteroic acid (DAMPA) crystalluria in a patient with osteosarcoma treated with carboxypeptidase-G2 rescue after high-dose methotrexate-induced nephrotoxicity.
- Author
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Berga F, Luna P, Martorell C, Rey J, Gomila I, Gimenez S, Costa-Bauza A, Elorza MÁ, Sánchez I, Grases F, and Barceló B
- Subjects
- Adult, Female, Humans, Hydrolysis, Kidney metabolism, Kidney pathology, Methotrexate chemistry, Methotrexate metabolism, Methotrexate therapeutic use, Methotrexate urine, Osteosarcoma drug therapy, Osteosarcoma pathology, Particle Size, Surface Properties, gamma-Glutamyl Hydrolase physiology, Kidney drug effects, Methotrexate adverse effects, Methotrexate analogs & derivatives, Osteosarcoma metabolism, gamma-Glutamyl Hydrolase metabolism
- Abstract
Background: High-dose methotrexate (HDMTX) therapy is a key component of many chemotherapy protocols. However, some patients develop HDMTX-induced nephrotoxicity. Carboxypeptidase-G2 (CPDG2) hydrolyses MTX into 2,4-diamino-N10-methylpteroic acid (DAMPA) and glutamic acid, and is used as a rescue agent in patients with nephrotoxicity and delayed elimination. Despite the frequency of HDMTX-induced renal injury, crystalluria is uncommon. Furthermore, crystals are rarely identified by conventional chemical methods., Objective: To determine the composition of crystalluria in a patient with osteosarcoma who was treated with CPDG2., Methods: Crystalluria was evaluated by optical microscopy, and chemical identification was performed by Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and Orbitrap™ high-resolution mass spectrometry (HRMS)., Results: The HRMS spectra of the patient's urine sediment showed a main peak at m/z 326.13, corresponding to the molecular mass of DAMPA [(C
15 H15 O2 N7 ) + H+ ]. The FT-IR spectral patterns of the sediment and DAMPA were not identical. SEM was unable to identify the crystal., Conclusion: DAMPA crystalluria was identified by Orbitrap™ HRMS in a patient treated with CPDG2 after HDMTX nephrotoxicity. This case reinforces the need to implement adequate measures to prevent nephrotoxicity. In cases of HDMTX-induced nephrotoxicity, urine sediment analysis should be requested., (Copyright © 2018. Published by Elsevier B.V.)- Published
- 2018
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5. Evaluation of inositol phosphates in urine after topical administration of myo-inositol hexaphosphate to female Wistar rats.
- Author
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Grases F, Costa-Bauzá A, Berga F, Rodríguez A, Gomila RM, Martorell G, and Martínez-Cignoni MR
- Subjects
- Administration, Topical, Animals, Diet, Female, Phytic Acid administration & dosage, Phytic Acid pharmacokinetics, Rats, Rats, Wistar, Skin Absorption, Inositol Phosphates urine, Phytic Acid pharmacology
- Abstract
Aims: Previous studies demonstrated a remarkable increase of urinary InsP
6 by topical administration. However, the methodology used for InsP6 analysis was not specific. The aim of this paper is to measure urinary inositol phosphates InsPs using more advanced methodologies and to compare the results with those obtained by the non-specific method., Materials and Methods: We fed 12 female rats with a diet without InsP6 for 16days. Then, we administered a topical InsP6 gel at high doses for 7days (50mgInsP6 /day) or at low doses for 28days (20mgInsP6 /day). We measured urine levels InsPs using a nonspecific method (based on the ability of InsPs to complex Al3+ ) and levels of InsP6 by a specific method (using polyacrylamide gel electrophoresis). Identification of different InsPs was performed by MS., Key Findings: At baseline, after dietary deprivation of InsP6 , rats only excreted InsP2 in their urine, and there was no detectable InsP6 or other InsPs. Rats given the high dose treatment for 7days had abundant urinary InsP6 , but also had other InsPs in their urine; cessation of InsP6 administration led to decreased levels of urinary InsPs. Rats given the low dose treatment for 28days had increasing levels of urinary InsPs over time. The maximum urinary InsP6 was at 21days, after which InsPs excretion decreased., Significance: We conclude that the skin can absorb InsP6 from a topical gel, and that InsP6 is excreted in the urine, along with other InsPs (InsP5 , InsP4 , InsP3 , and InsP2 )., (Copyright © 2017 Elsevier Inc. All rights reserved.)- Published
- 2018
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6. Quantification of xanthine- and uric acid-related compounds in urine using a "dilute-and-shoot" technique coupling ultra-high-performance liquid chromatography and high-resolution Orbitrap mass spectrometry.
- Author
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Rodriguez A, Gomila RM, Martorell G, Costa-Bauza A, and Grases F
- Subjects
- Humans, Limit of Detection, Linear Models, Reproducibility of Results, Chromatography, High Pressure Liquid methods, Mass Spectrometry methods, Uric Acid urine, Xanthines urine
- Abstract
Quantitative analysis of relevant metabolites in biofluids such as urine is often a tedious procedure, since it usually requires extraction, purification or preconcentration. For instance, in the analysis of methylxanthines in urine, a solid-phase extraction is often required. In the current work, a rapid and highly sensitive "dilute-and-shoot" method combining ultra-high-performance liquid chromatography and high-resolution mass spectrometry (UHPLC/HRMS) was validated for urinary determination of twelve analytes: uric acid, hypoxanthine, xanthine, 1-methyluric acid, 1,3-dimethyluric acid, 1-methylxanthine, 3-methylxanthine, 7-methylxanthine, theophylline, theobromine, paraxanthine and caffeine. These analytes are the major physiological metabolites of caffeine, theobromine or theophylline, or final products of purine catabolism. The separation was carried out on a core-shell Kinetek EVO C
18 column coupled to a Q Exactive Orbitrap high-resolution mass spectrometer equipped with a heated electrospray ionization (HESI) probe, that operated both in positive and negative ionization modes. The twelve analytes eluted from between 1.5 and 10.5min. The lower limit of quantification (LLOQ) values ranged from 0.25 to 2.5ng/mL, and the calibration curves were linear from the LLOQ to 100ng/mL. The only pretreatment needed was to dilute each urine sample (typically to 1/500) with 0.1% formic acid solution, and then filter the diluted sample before injecting it into the UHPLC system. With this high dilution, there were no significant matrix effects, and the intra- and inter-day precision and accuracy values were acceptable (coefficients of variance and relative errors below 15%, except for the LLOQ, for which they were below 20%). Furthermore, the analysis of spiked urine samples with 25ng/mL of the target analytes showed excellent recoveries and precision levels for the twelve analytes. To our knowledge, there is no other published method that allows for the simultaneous determination of the concentrations of these twelve compounds, nor has a previously reported method been indicated to show such low LLOQ values as we have for the majority of the analytes. We expect our protocol to be useful for nutritional assessments, interventional studies, kidney stone research, and purine metabolism studies., (Copyright © 2017 Elsevier B.V. All rights reserved.)- Published
- 2017
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7. Plant phosphates, phytate and pathological calcifications in chronic kidney disease.
- Author
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Buades Fuster JM, Sanchís Cortés P, Perelló Bestard J, and Grases Freixedas F
- Subjects
- Animals, Antioxidants metabolism, Arteriosclerosis prevention & control, Biological Availability, Calcinosis etiology, Cardiovascular Diseases etiology, Cardiovascular Diseases mortality, Chronic Kidney Disease-Mineral and Bone Disorder etiology, Chronic Kidney Disease-Mineral and Bone Disorder prevention & control, Cinacalcet therapeutic use, Cross-Sectional Studies, Fabaceae, Humans, Hyperphosphatemia mortality, Male, Molecular Structure, Nuts, Observational Studies as Topic, Osteoporosis drug therapy, Osteoporosis etiology, Phosphorus, Dietary administration & dosage, Phosphorus, Dietary adverse effects, Phytic Acid pharmacology, Phytic Acid therapeutic use, Prospective Studies, Rats, Renal Insufficiency, Chronic complications, Renal Insufficiency, Chronic diet therapy, Urolithiasis etiology, Calcinosis prevention & control, Cardiovascular Diseases prevention & control, Hyperphosphatemia complications, Phosphates metabolism, Phosphorus, Dietary pharmacokinetics, Phytic Acid metabolism, Renal Insufficiency, Chronic metabolism, Urolithiasis prevention & control
- Abstract
Phytate, or myo-inositol 1,2,3,4,5,6-hexakis dihydrogen phosphate (InsP6), is a naturally occurring phosphorus compound that is present in many foods, mainly legumes, whole grains and nuts. Patients with chronic kidney disease (CKD) have cardiovascular disease mortality up to 30times higher than the general population. Vascular calcifications (VCs) directly contribute to overall morbidity and mortality, especially in CKD. In part, this high mortality is due to elevated levels of phosphorus in the blood. Therefore, control of dietary phosphorus is essential. Dietary phosphorus can be classified according to its structure in organic phosphorus (plant and animal) and inorganic (preservatives and additives). Plant-phosphorus (legumes and nuts), mainly associated with InsP6, is less absorbable by the human gastrointestinal tract as the bioavailability of phosphorous from plant-derived foods is very low. Recent data indicate that restriction of foods containing plant phosphates may compromise the adequate supply of nutrients that have a beneficial effect in preventing cardiovascular events, such as InsP6 or fibre found in legumes and nuts. Experimental studies in animals and observational studies in humans suggest that InsP6 can prevent lithiasis and VCs and protect from osteoporosis. In conclusion, we need prospective studies to elucidate the potential benefits and risks of phytate (InsP6) through the diet and as an intravenous drug in patients on haemodialysis., (Copyright © 2016 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.)
- Published
- 2017
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8. Application of nuclear magnetic resonance spectroscopy for identification of ciprofloxacin crystalluria.
- Author
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Morell-Garcia D, Barceló B, Rodriguez A, Liñeiro V, Robles R, Vidal-Puigserver J, Costa-Bauzá A, and Grases F
- Subjects
- Adult, Anti-Bacterial Agents urine, Ciprofloxacin urine, Crystallization, Humans, Male, Microscopy, Electron, Anti-Bacterial Agents adverse effects, Ciprofloxacin adverse effects, Proton Magnetic Resonance Spectroscopy methods
- Abstract
This is a report describing a previously healthy young patient, who experienced crystalluria and non-cholestatic acute liver injury after a single intravenous dose of 400mg. The nuclear magnetic resonance spectra confirmed that the urinary sediment in our patient was formed by pure ciprofloxacin. The nuclear magnetic resonance spectra ((1)H NMR) of the urine sediment are a good test to confirm the composition of the crystals observed by electron microscopy and infrared spectrum. The findings indicate the importance of adequate hydration, urinalysis, measurement of pH and liver enzyme levels, prior to treatment with ciprofloxacin. Our findings also indicate that ciprofloxacin should not be administered to patients with renal tubular acidosis, due to their high urinary pH., (Copyright © 2014 Elsevier B.V. All rights reserved.)
- Published
- 2015
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9. Phytate levels in biological fluids of mammals.
- Author
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Perelló J and Grases F
- Subjects
- Animals, Humans, Chromatography, High Pressure Liquid methods, Mass Spectrometry methods, Phytic Acid blood
- Published
- 2014
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10. Validation of an LC-MS bioanalytical method for quantification of phytate levels in rat, dog and human plasma.
- Author
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Tur F, Tur E, Lentheric I, Mendoza P, Encabo M, Isern B, Grases F, Maraschiello C, and Perelló J
- Subjects
- Animals, Dogs, Humans, Limit of Detection, Linear Models, Rats, Chromatography, High Pressure Liquid methods, Mass Spectrometry methods, Phytic Acid blood
- Abstract
Myo-inositol hexakisphosphate (phytate, IP6) is a naturally occuring compound whose determination in biological matrices is chanllenging. Several benefitial properties have been attributed to IP6 in parallel with the development of suitable analytical methodologies for its analytical determination in urine and some tissues. However, there is a lack of appropriate tools for its determination in plasma samples. In this paper, a direct, sensitive and selective bioanalytical method for the determination of IP6 based on LC-MS is presented. It is the first method published to quantify IP6 in plasma matrices directly through its molecular weight, being consequently a highly specific methodology. The method has been validated in rat, dog and human plasma, according to the acceptance criteria laid down in the FDA guidance Bioanalytical Method Validation. Accuracy and precision were not greater than 15% at medium and high concentrations and not greater than 20% at the LLOQ concentration. The mean absolute recovery obtained ranged from 78.74 to 102.44%, 62.10 to 87.21% and 61.61 to 86.99% for rat, dog and human plasma respectively. The LLOQ was 500ngmL(-1) due to the presence of endogenous IP6 in blank plasma samples and the limit of detection was within the range 30-80ngmL(-1)., (Copyright © 2013 Elsevier B.V. All rights reserved.)
- Published
- 2013
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11. Determination of uric acid in urine, saliva and calcium oxalate renal calculi by high-performance liquid chromatography/mass spectrometry.
- Author
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Perelló J, Sanchis P, and Grases F
- Subjects
- Calcium Oxalate chemistry, Humans, Mass Spectrometry methods, Reproducibility of Results, Uric Acid urine, Chromatography, High Pressure Liquid methods, Kidney Calculi chemistry, Saliva chemistry, Uric Acid analysis
- Abstract
A very simple and direct method for determination of uric acid, in various biological matrices, based on high-performance liquid chromatography and mass spectrometry is described. Chromatographic separations were performed with a stationary phase Zorbax Sax Column, an anion exchange resin, with 50% sodium citrate 1 mM at pH 6.5 and 50% acetonitrile as mobile phase delivered at a flow rate of 1 ml/min. The detector counted negative ions by monitoring m/z 167.1, which corresponds to the urate anion. The method does not use an internal standard but quality control samples were used. Intra-day precision ranged between 1.1 and 1.5%, whereas inter-day precision was between 1.3 and 2.8% (n=5) working with some selected standards. Recovery tests of added standard have been successfully performed in urine and saliva samples, thus showing an appropriate accuracy of the method. The limit of quantitation found was 70 microg/l. Different urine and saliva samples were analyzed using an alternative analytical methodology based on an enzymatic reaction and photometric detection at 520 nm, resulting both methods comparable at a 95% confidence level. The method has been also applied to the determination of trace amounts of uric acid in the core of some selected calcium oxalate renal calculi.
- Published
- 2005
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12. Dietary myo-inositol hexaphosphate prevents dystrophic calcifications in soft tissues: a pilot study in Wistar rats.
- Author
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Grases F, Perelló J, Prieto RM, Simonet BM, and Torres JJ
- Subjects
- Administration, Oral, Animals, Calcinosis chemically induced, Disease Models, Animal, Etidronic Acid administration & dosage, Etidronic Acid pharmacology, Injections, Subcutaneous, Male, Pilot Projects, Potassium Permanganate toxicity, Rats, Rats, Wistar, Calcinosis prevention & control, Diet, Phytic Acid administration & dosage, Phytic Acid pharmacology
- Abstract
Myo-inositol hexaphosphate (InsP6) is an abundant component of plant seeds. It is also found in significant levels in blood and mammalian tissues, but they are totally dependent on their dietary intake. In the present paper, we describe studies on the effect of InsP6 on a model of dystrophic calcification, which was chemically induced by subcutaneous injection of a 0.1% KMnO4 solution. Male Wistar rats were randomly divided into four groups for treatment over 31 days. A: animals consuming a purified diet in which InsP6 was absent but to which 1% of InsP6 (as sodium salt) was added. In this group, the InsP6 plasma levels (0.393 +/- 0.013 microM) were similar to those observed in rats consuming a standard diet. B: animals consuming only the purified diet in which InsP6 was absent. In this case the InsP6 plasma levels decreased (0.026 +/- 0.006 microM); C: animals consuming the same purified diet as group B but received daily subcutaneous injections of 50 microg kg(-1) etidronate during the last 14 days. In this case the InsP6 plasma levels were also very low (0.025 +/- 0.007 microM); D: animals consuming the same diet as group B but a 6% of carob germ (InsP6 rich product) was added. The InsP6 plasma levels (0.363 +/- 0.035 microM) were also similar to those observed in rats consuming a standard diet. After 21 days plaque formation was induced. Calcification plaques were allowed to proceed for 10 days, after which the plaque material present was excised, dried and weighed. It was found that the presence of myo-inositol hexaphosphate (phytate) in plasma at normal concentrations (0.3-0.4 microM) clearly inhibited the development of dystrophic calcifications in soft tissues. These results demonstrates that myo-inositol hexaphosphate acts as an inhibitor of calcium salt crystallization.
- Published
- 2004
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13. Determination of myo-inositol in biological samples by liquid chromatography-mass spectrometry.
- Author
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Perelló J, Isern B, Costa-Bauzá A, and Grases F
- Subjects
- Humans, Reproducibility of Results, Sensitivity and Specificity, Chromatography, High Pressure Liquid methods, Inositol urine, Mass Spectrometry methods
- Abstract
Due to the absence of HPLC methods to determine myo-inositol using mass detection and considering its sensitivity and selectivity, a high performance liquid chromatography-mass spectrometry method for the analysis of myo-inositol is described and applied to its direct determination in urine and saliva samples. Successful resolution of myo-inositol and its related substances was achieved with a stationary phase Aminex HPX-87C Column with milli-Q water as mobile phase and 5 mM ammonium acetate added post-column. The detector counted positive ions by monitoring m/z = 198, which corresponds to the myo-inositol adduct with ammonium cation. Urine and saliva samples were previously purified by passing through an anion-exchange resin. Concentrations as low as 138 and 461 microg/l in saliva and urine could be respectively quantified. Intra-day R.S.D. ranged from 0.83 to 1.02%, whereas inter-day R.S.D. was between 1.54 and 3.58%.
- Published
- 2004
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14. Sialolithiasis: mechanism of calculi formation and etiologic factors.
- Author
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Grases F, Santiago C, Simonet BM, and Costa-Bauzá A
- Subjects
- Adult, Crystallization, Diet, Electron Probe Microanalysis, Humans, Hydrogen-Ion Concentration, Phytic Acid chemistry, Saliva chemistry, Salivary Calculi pathology, Spectrophotometry, Infrared, Salivary Calculi chemistry, Salivary Gland Calculi etiology, Salivary Gland Calculi metabolism
- Abstract
Background: Sialolithiasis is a common disease of salivary glands. The etiology of these calculi is little known and their exact mechanism of formation is unknown., Methods: The composition and structure of 21 sialoliths were studied and the composition of the saliva of each corresponding patient was determined (pH, calcium, magnesium, phosphorus, citrate and phytate)., Results: Eighteen sialoliths exhibited similar macro and microstructure, being constituted by hydroxyapatite (HAP) and organic matter, normally arranged in a multilayer structure. The three remaining sialoliths were exclusively constituted by organic matter. The salivary Ca of patients with HAP calculi was significantly higher than that found in the saliva of the healthy group. The salivary phytate concentration of patients with HAP calculi was significantly inferior to that found in patients with calculi exclusively formed by organic matter, as well as to that found in saliva of healthy group. Significant differences between the salivary magnesium concentrations of patients with HAP calculi and the control group were also observed. No significant differences between pH and citrate concentrations of the three groups were found., Conclusions: It was concluded that the deficit of crystallization inhibitors such as myo-inositol hexaphosphate (phytate) was also an important etiologic factor implied in the sialolith development.
- Published
- 2003
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15. Effects of exogenous inositol hexakisphosphate (InsP(6)) on the levels of InsP(6) and of inositol trisphosphate (InsP(3)) in malignant cells, tissues and biological fluids.
- Author
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Grases F, Simonet BM, Vucenik I, Perelló J, Prieto RM, and Shamsuddin AM
- Subjects
- Animal Feed standards, Animals, Brain drug effects, Brain metabolism, Brain Chemistry, Breast Neoplasms chemistry, Chromatography, High Pressure Liquid, Diet, Female, Gas Chromatography-Mass Spectrometry, Humans, Inositol 1,4,5-Trisphosphate analysis, Phytic Acid administration & dosage, Phytic Acid analysis, Rats, Rats, Wistar, Tumor Cells, Cultured chemistry, Tumor Cells, Cultured drug effects, Tumor Cells, Cultured metabolism, Breast Neoplasms metabolism, Inositol 1,4,5-Trisphosphate metabolism, Leukemia metabolism, Phytic Acid pharmacokinetics
- Abstract
InsP(6) is abundant in cereals and legumes. InsP(6) and lower inositol phosphates, in particular InsP(3), participate in important intracellular processes. In addition, InsP(6) possess significant health benefits, such as anti-cancer effect, kidney stones prevention, lowering serum cholesterol. Because of the insensitivity of existing methods for determination of non-radiolabeled inositol phosphates, little is known about the natural occurrence, much less on the concentrations of InsP(6) and InsP(3) in biological samples. Using gas chromatography-mass detection analysis of HPLC chromatographic fractions, we report a measurement of unlabeled total InsP(3) and InsP(6) (a) as they occur within cells culture, tissues, and plasma, and (b) their changes depending on the presence of exogenous InsP(6). When rats were fed on a purified diet in which InsP(6) was undetectable (AIN-76A) the levels of InsP(6) in brain were 3.35 +/- 0.57 (SE) micromol.kg(-1) and in plasma 0.023 +/- 0.008 (SE) micromol.l(-1). The presence of InsP(6) in diet dramatically influenced its levels in brain and in plasma. When rats were given an InsP(6)-sufficient diet (AIN-76A + 1% InsP(6)), the levels of InsP(6) were about 100-fold higher in brain tissues (36.8 +/- 1.8 (SE)) than in plasma (0.29 +/- 0.02 (SE)); InsP(6) concentrations were 8.5-fold higher than total InsP(3) concentrations in either plasma (0.033 +/- 0.012 (SE)) and brain (4.21 +/- 0.55 (SE)). When animals were given an InsP(6)-poor diet (AIN-76A only), there was a 90% decrease in InsP(6) content in both brain tissue and plasma (p < 0.001); however, there was no change in the level of total InsP(3). In non-stimulated malignant cells (MDA-MB 231 and K562) the InsP(6) contents were 16.2 +/- 9.1 (SE) micromol.kg(-1) for MDA-MB 231 cells and 15.6 +/- 2.7 (SE) for K 562 cells. These values were around 3-fold higher than those of InsP(3) (4.8 +/- 0.5 micromol.kg(-1) and 6.9 +/- 0.1 (SE) for MDA-MB 231 and K562 cells respectively). Treatment of malignant cells with InsP(6) resulted in a 2-fold increase in the intracellular concentrations of total InsP(3) (9.5 +/- 1.3 (SE) and 10.8 +/- 1.0 (SE) micromol.kg(-1) for MDA-MB 231 and K562 cells respectively, p < 0.05), without changes in InsP(6) levels. These results indicate that exogenous InsP(6) directly affects its physiological levels in plasma and brain of normal rats without changes on the total InsP(3) levels. Although a similar fluctuation of InsP(6) concentration was not seen in human malignant cell lines following InsP(6) treatment, an increased intracellular levels of total InsP(3) was clearly observed.
- Published
- 2002
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16. Simple classification of renal calculi closely related to their micromorphology and etiology.
- Author
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Grases F, Costa-Bauzá A, Ramis M, Montesinos V, and Conte A
- Subjects
- Calcium Oxalate analysis, Calcium Oxalate urine, Cystine analysis, Cystinuria urine, Electron Probe Microanalysis, Female, Humans, Hydroxyapatites analysis, Hydroxyapatites urine, Kidney Calculi chemistry, Kidney Calculi urine, Male, Spectrophotometry, Infrared, Uric Acid analysis, Uric Acid urine, Kidney Calculi classification, Kidney Calculi etiology
- Abstract
Background: Classification of renal calculi with clear correlation with the main urinary etiological conditions has been previously established. However, such information is complex and difficult to adapt to clinical routine practice., Methods: A simple classification of renal calculi based on their structure and composition is proposed and applied to 2500 renal calculi to achieve the percentage of each category. The urines of 700 individuals chosen randomly have been analyzed and the results compared with those obtained with 51 healthy subjects., Results: 12.9% calculi corresponded to calcium oxalate monohydrate papillary calculi, 16.4% to calcium oxalate monohydrate unattached calculi, 33.8% to calcium oxalate dihydrate calculi, 11.2% calcium oxalate dihydrate/hydroxyapatite mixed calculi, 7.1% hydroxyapatite calculi, 4.1% struvite calculi, 0.6% brushite calculi, 8.2% uric acid calculi, 2.6% calcium oxalate/uric acid mixed calculi, 1.1% cystine calculi and 1.9% various infrequent calculi. Based on the corresponding urinary analytical studies, each kind of calculus is related with the more frequently associated urinary alterations., Conclusions: An important aspect of this classification is the possibility to establish, by means of the correct study of the calculus, some of the main possible etiologic factors closely related to its formation., (Copyright 2002 Elsevier Science B.V.)
- Published
- 2002
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17. Determination of pyrophosphate in renal calculi and urine by means of an enzymatic method.
- Author
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March JG, Simonet BM, and Grases F
- Subjects
- Algorithms, Cystine analysis, Diphosphates urine, Fructose-Bisphosphate Aldolase chemistry, Humans, Hydrogen-Ion Concentration, Indicators and Reagents, Kidney Calculi urine, Oxalates analysis, Oxalates urine, Reference Values, Spectrophotometry, Ultraviolet, Uric Acid analysis, Uric Acid urine, Diphosphates analysis, Kidney Calculi chemistry
- Abstract
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 also reported. The pyrophosphate content was dependent on the calculi composition. The highest amount of pyrophosphate was found in hydroxyapatite calculi (of the order of 10 microg/g), struvite and oxalate calculi showed a lower amount (the order was 2.5 and 4.5 microg/g, respectively) and was not detected in uric acid and cystine stones. The method was also successfully applied to the determination of pyrophosphate in human urine. For urinary pyrophosphate determination, a modification based on a clean-up of urine using activated carbon has been proposed. Pyrophosphate in human urine was of the order of 4 mg l(-1).
- Published
- 2001
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18. Determination of phytic acid by gas chromatography-mass spectroscopy: application to biological samples.
- Author
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March JG, Simonet BM, and Grases F
- Subjects
- Animals, Humans, Hydrolysis, Phytic Acid blood, Phytic Acid urine, Rats, Reproducibility of Results, Sensitivity and Specificity, Gas Chromatography-Mass Spectrometry methods, Phytic Acid analysis
- Abstract
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 working range 18-500 microg l(-1) phytic acid, and coefficient of variation 1.9%. The method has been successfully applied to a variety of biological samples: various rat organs (kidney, liver, brain and bone), human plasma and urine and kidney stones. A comparative study of sample treatments, including deproteization, lipid extraction and the presence of a chelator, is also reported. Phytic acid amounts found in rat organs ranged from 1.07 g kg(-1) for bone to 32.0 g kg(-1) for brain. Phytic acid in human plasma was of the order of 0.14 mg l(-1). In kidney stones, phytic acid was found in calcium containing stones.
- Published
- 2001
- Full Text
- View/download PDF
19. Uric acid calculi: types, etiology and mechanisms of formation.
- Author
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Grases F, Villacampa AI, Costa-Bauzá A, and Söhnel O
- Subjects
- Chemical Phenomena, Chemical Precipitation, Chemistry, Physical, Crystallization, Humans, Hydrogen-Ion Concentration, Solubility, Thermodynamics, Uric Acid analysis, Uric Acid chemistry, Urinary Calculi chemistry, Urinary Calculi etiology
- Abstract
The study of the composition and structure of 41 stones composed of uric acid was complemented by in vitro investigation of the crystallization of uric acid. Uric acid dihydrate (UAD) precipitates from synthetic urine under physiological conditions when the medium is supersaturated with respect to this compound, though uric acid anhydrous (UAA) represents the thermodynamically stable form. Solid UAD in contact with liquid transforms into UAA within 2 days. This transition is accompanied by development of hexagonal bulky crystals of UAA and appearance of cracks in the UAD crystals. Uric acid calculi can be classified into two groups, differing in outer appearance and inner structure. Type I includes stones with a little central core and a compact columnar UAA shell and stones with interior structured in alternating densely non-columnar layers developed around a central core; both of them are formed mainly by crystalline growth at low uric acid supersaturation. Type II includes porous stones without inner structure and stones formed by a well developed outermost layer with an inner central cavity; this type of stones is formed mainly by sedimentation of uric acid crystals generated at higher uric acid supersaturation.
- Published
- 2000
- Full Text
- View/download PDF
20. Biopathological crystallization: a general view about the mechanisms of renal stone formation.
- Author
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Grases F, Costa-Bauzá A, and García-Ferragut L
- Subjects
- Calcium Oxalate analysis, Crystallization, Humans, Kidney Calculi ultrastructure, Phosphates analysis, Uric Acid analysis, Kidney Calculi chemistry, Kidney Calculi etiology
- Abstract
A general classification of most common renal calculi (calcium oxalate, phosphate and uric acid stones) based on their formation mechanism is presented. The main etiological factors that enable their development are discussed considering present knowledge of calcium oxalate, insoluble urinary phosphates and uric acid crystallization and the fine structure of respective renal stones. Considering the formation mechanisms of the discussed calculi, common aspects permit us to distinguish two general mechanisms of calculi formation: development of calculi attached to papillary epithelium and development of calculi in cavities without any attachment to urothelium.
- Published
- 1998
- Full Text
- View/download PDF
21. Vitamin A and urolithiasis.
- Author
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Grases F, Garcia-Gonzalez R, Genestar C, Torres JJ, and March JG
- Subjects
- Animals, Humans, Male, Rats, Rats, Wistar, Vitamin A blood, Vitamin E blood, Urinary Calculi etiology, Vitamin A Deficiency complications
- Abstract
The effects of vitamin A deficiency on urolithiasis were investigated in male rats. A vitamin A-deficient diet caused important changes in the composition of the urine of the treated rats when compared with controls. One of the main effects was a decrease in the concentration of urinary glycosaminoglycans and zinc in the rats receiving the vitamin A-deficient diet. Significant differences were also found in plasma vitamin E and in the relation of vit E/vit A between treated and control groups but, in general, with no important differences in vitamin A. Nevertheless, significant differences in kidney content of vitamin A were observed between both groups. On the other hand, lesions of the cuboidal epithelium that covers the papillae in rats treated with the vitamin A-deficient diet were severe when compared with controls. The vitamin A and E plasma levels in urolithiasic humans were also investigated and compared with those found in a control group. No significant differences were observed in plasma vitamin A levels; nevertheless a significant increase in vitamin E and in the vit E/vit A ratio was clearly observed. These results could be related to a possible deficit of vitamin A in kidneys of stone formers, this being one of the diverse factors that can contribute to urolith development. Moreover, the deficit of important urinary crystallization inhibitors normally found in stone-formers, such as pyrophosphate and phytate, can also be related to the presence of low levels of renal vitamin A which prevents the enzymatic degradation of such inhibitors.
- Published
- 1998
- Full Text
- View/download PDF
22. Simple test to evaluate the risk of urinary calcium stone formation.
- Author
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Grases F, García-Ferragut L, Costa-Bauzá A, Conte A, and García-Raja A
- Subjects
- Adult, Aged, Calcium Oxalate urine, Case-Control Studies, Crystallization, Female, Humans, In Vitro Techniques, Male, Middle Aged, Risk Factors, Sensitivity and Specificity, Urinary Calculi diagnosis, Urine chemistry, Urinary Calculi etiology, Urinary Calculi urine
- Abstract
A simple test to evaluate the capacity of a urine to crystallize calcium salts is presented. The test is based on the fact that if a non-protected non-renewed surface remains in contact with a urine, sooner or later the contained supersaturated substances crystallize on it. Thus, by using an adequate surface, it is possible to derive a period within which a normal urine does not crystallize whereas a lithogenic urine induces the growth of calcium salts. The test was applied to urines of oxalocalcic stone-formers and healthy people and showed an excellent discrimination between clearly abnormal and healthy urines. Semiologic analysis of the data is also included.
- Published
- 1997
- Full Text
- View/download PDF
23. Phosphates precipitating from artificial urine and fine structure of phosphate renal calculi.
- Author
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Grases F, Sohnel O, Vilacampa AI, and March JG
- Subjects
- Calcium Phosphates urine, Chemical Precipitation, Crystallization, Kidney Calculi etiology, Magnesium Compounds urine, Phosphates chemistry, Struvite, Kidney Calculi chemistry, Kidney Calculi ultrastructure, Phosphates urine
- Abstract
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 (HAP) precipitated at pH < or = 7.0 and struvite with HAP at pH > 7.0. HAP was formed exclusively from magnesium deficient urine at pH 7.0. Newberyite, octacalcium phosphate and whitlockite were not identified. The chemical and phase composition and inner fine structure of 14 phosphate calculi were studied. Three types of stones were distinguished based on their magnesium content: (i) stones rich in magnesium composed of struvite, hydroxyapatite and abundant organic matter, (ii) stones with low magnesium content constituted by calcium deficient hydroxyapatite, up to 5% of struvite, considerable amount of organic matter and occasionally brushite, and (iii) calculi without magnesium consisting of brushite, hydroxyapatite and little organic matter. Conditions prevaling during stone-formation assessed for each type of stone were confirmed by corresponding urinary biochemical data and corroborate the in vitro studies of phosphates precipitation.
- Published
- 1996
- Full Text
- View/download PDF
24. Calcium oxalate monohydrate renal calculi. Formation and development mechanism.
- Author
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Söhnel O and Grases F
- Subjects
- Crystallization, Humans, Kidney Calculi etiology, Calcium Oxalate chemistry, Kidney Calculi chemistry
- Abstract
Available information relevant to stone genesis on both calcium oxalate monohydrate crystallization and fine inner structure of papillary calculi is reviewed. Integration of attained facts facilitated formulating a feasible mechanism of papillary calculi formation and development. Medical implications of this mechanism are assessed.
- Published
- 1995
- Full Text
- View/download PDF
25. Crystallization of organic crystals with "tailor-made" inhibitors. Determination of L-lysine using L-glutamic acid as substrate.
- Author
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Grases F and Genestar C
- Abstract
A very simple turbidimetric procedure is used for determination of L-lysine, based on its inhibitory action on the crystallization of L-glutamic acid. The obtention of supersaturated solutions of L-glutamic acid was accomplished by means of the change in the solvent composition. Thus, the addition of ethanol to stable aqueous solutions of this amino acid allows the obtainment of unstable supersaturated solutions. The method suffers from very few interferences and permits the development of an analytical procedure to determine L-lysine in the presence of D-lysine. The method was also applied to the determination of L-lysine in pharmaceutical products.
- Published
- 1993
- Full Text
- View/download PDF
26. A potentiometric technique for kinetic determination of citrate, based on inhibition of crystalline growth of lead carbonate seed crystals.
- Author
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Grases F and Genestar C
- Abstract
The growth of lead carbonate seed crystals is strongly inhibited by the presence of citric acid. The kinetics of crystal growth were followed potentiometrically with a lead ion-selective electrode. The study of different variables on such a process was carried out with the aim of developing kinetic procedures to determine citrate (0.5-2.0 mug/ml). The selectivity and sensitivity of these processes allow the application of his crystallization reaction to direct determination of citrate in drinks and in a pharmaceutical product.
- Published
- 1991
- Full Text
- View/download PDF
27. Rapid determination of urinary oxalate by high-performance liquid chromatography.
- Author
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Millán A, Grases JM, and Grases F
- Subjects
- Animals, Chromatography, High Pressure Liquid, Ferric Compounds analysis, Humans, Indicators and Reagents, Oxalic Acid, Rats, Spectrophotometry, Ultraviolet, Oxalates urine
- Published
- 1990
- Full Text
- View/download PDF
28. Fluorimetric reaction-rate methods of inorganic analysis: a review.
- Author
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Valcárcel M and Grases F
- Abstract
A review is given of the utilization in analytical chemistry of the rate of fluorescence reactions of inorganic species. These methods are of recent development and suggest the possibility of further analytical procedures. Two main types of methods, enzymatic and non-enzymatic, are distinguished, and their applications to inorganic analysis are discussed.
- Published
- 1983
- Full Text
- View/download PDF
29. Iron(III) as activator for catalytic fluorimetric microdetermination of V(V).
- Author
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Navas A, Santiago M, Grases F, Laserna JJ, and Sanchez FG
- Abstract
The activation of the vanadium(V)-catalysed aerial oxidation of sodium 4,8-diamino-1,5 -dihydroxyanthraquinone-2,6-disulphonate by iron(III) is discussed. The oxidation product is intensely fluorescent and allows fluorescence-monitoring of the slow reaction, which is preceded by an induction period. On the basis of this investigation, an accurate method for determination of vanadium(V) at the 1-10 ng/ml level has been developed.
- Published
- 1982
- Full Text
- View/download PDF
30. Kinetic fluorimetric determination of traces of vanadium(V) by means of a catalysed autoxidation process.
- Author
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Sanchez FG, Navas A, Santiago M, and Grases F
- Abstract
A kinetic method for determination of traces of vanadium(V) (0.04-0.5 ppm) is described. It is based on the catalytic action of vanadate in the autoxidation of sodium 4,8-diamino-1,5-dihydroxyanthraquinone-2,6-disulphonate, giving rise to kinetic curves characterized by an induction period before the appearance of a product exhibiting an intense red fluorescence in acidic solution. This product has been investigated and the experimental variables and interferences have been studied.
- Published
- 1981
- Full Text
- View/download PDF
31. A simple thermometric technique for reaction-rate determination of inorganic species, based on the iodide-catalysed cerium(IV)-arsenic(III) reaction.
- Author
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Grases F, Forteza R, March JG, and Cerda V
- Abstract
A very simple reaction-rate thermometric technique is used for determination of iodide (5-20 ng ml ), based on its catalytic action on the cerium(IV)-arsenic(III) reaction, and for determination of mercury(II) (1.5-10 ng ml ) and silver(I) (2-10 ng ml ), based on their inhibitory effect on this reaction. The reaction is followed by measuring the rate of temperature increase. The method suffers from very few interferences and is applied to determination of iodide in biological and inorganic samples, and Hg(II) and Ag(I) in pharmaceutical products.
- Published
- 1985
- Full Text
- View/download PDF
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