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M Daudon

Publications and source records attributed to M Daudon.

At least 73 records · Page 4Linked to original sources
PubMed1994

Influence of various calcium intakes on calcium-oxalate crystalluria in rats on sodium-oxalate diet.

Forty adult male Wistar rats were placed in metabolic cages on a Ca-deficient diet (0.1%) for 7 days and then on a Ca-deficient, Na-oxalate (NaOx) enriched diet (20 mg/100 g) for another 14 days. The animals were subdivided into three groups receiving three different types of mineral water: group I (n = 13), Badoit (Ca 222 mg/l); group II (n = 14), Contrexéville (Ca 467 mg/l); and group III (n = 13), Evian (Ca 78 mg/l). Another series of 25 rats (group I, n = 9; group II, n = 8; group III, n = 8) underwent the same study protocol, except that they received a normal Ca diet (1%). On the low-Ca diet, urinary Ca-Ox monohydrate (COM) crystals were observed only under the Na-Ox diet, with a mean crystal number significantly greater in group III (16.7 +/- 4.5 crystals/mm3) than in group I or II rats (2.5 +/- 1.5 or 4.1 +/- 1.5 crystals/mm3, respectively). Urinary Ca concentrations decreased in all groups (P < 0.001) under the Na-Ox diet, while urinary oxalate concentrations increased in all groups (P < 0.001). On the normal Ca diet, COM crystal excretion was observed only with the Na-Ox-enriched diet, but in this case feeding the Na-Ox diet did not modify urinary oxalate excretion. Ca/Ox ratio was significantly lower under 0.1% Ca diet than under normal Ca diet, related with the type and the number of crystals observed, demonstrating that assessment of crystalluria can provide an index of disease severity. Moreover, the hardness of the drinking water influences urinary COM crystal excretion only under a low-Ca, oxalate-rich diet, suggesting that the total calcium intake rather than the water calcium content is an important factor in the occurrence of Ca-Ox nephrolithiasis.

Animals↗
PubMed1994

Methodological aspects of spontaneous crystalluria studies in calcium stone formers.

Despite nearly a half-century of study, the clinical value of spontaneous crystalluria (Cx) examinations in calcium stone formers (CaSF) is still uncertain. The analytical complexity of urine particle study is largely responsible for this situation. As a result, there is no consensus regarding technical methods in Cx with several techniques for urine sampling and three different instruments currently used for particle study, namely, particle counting (PC), light microscopy (LM) and petrographic microscopy (PM). In this work, we first examined urine sampling and instrument methods regarding their appropriateness for Cx studies. Then we performed a comparative analysis of Cx studies in CaSF. Despite many technical and clinical discrepancies, several studies agree that the frequency of "all particles" and of the weddellite and whewellite calcium oxalate (CaOx) crystalline phases are increased in CaSF as compared to normal subjects (NS). Particle sizes and aggregation ratio are also often increased. Altogether, these results reinforce the need for an efficient method for Cx studies in these patients. Examining each technique leads us to conclude that most particle parameters can be studied by "direct LM" observation of freshly voided urine samples, i.e., urine samples without any separation steps. For clinical applications, several examinations should be performed, first to define the specific Cx characteristics in a patient, then for the study of treatment efficiency on Cx control, and finally, during the patient follow-up. Due to Cx variability in each patient, the frequency of Cx examinations during each phase needs to be determined in longterm comparative prospective studies of CaSF.

Calcium↗
PubMed1993

Molecular characteristics of uronic-acid-rich protein, a strong inhibitor of calcium oxalate crystallization in vitro.

Uronic-acid-rich protein (UAP) is a new urinary macromolecule which strongly inhibits calcium oxalate crystal formation. It is a glycoprotein with a molecular weight of about 35,000 Da, and its carbohydrate content is 8.5%. This inhibitor is composed of two polypeptidic chains crosslinked by chondroitin sulfate. It exhibits partial structural homology with alpha 1-microglobulin. The inhibitory activity seems to be supported by peptidic chains as determined by enzymatic assay.

Amino Acid Sequence↗
PubMed1993

Isolation and purification of a new glycoprotein from human urine inhibiting calcium oxalate crystallization.

A calcium oxalate crystal growth inhibitor was isolated from human urine using DEAE-Sephacel gel followed by Sephacryl S-300 chromatography and FPLC column. The isolated inhibitor was a uronic-acid-rich protein (UAP). It was found to be a glycoprotein with a molecular weight of 35,000 Da as determined by SDS-polyacrylamide gel electrophoresis. Inhibitory activity was demonstrated using a calcium oxalate crystallization system. In addition UAP, nephrocalcin (NC) or nephrocalcin-like (NC-like) activity was an effective inhibitor in this system. However, the inhibitory activity of UAP appeared to be higher than that of NC or NC-like activity. This finding suggests that NC or NC-like activity is not only urinary protein with strong inhibitory activity. UAP and probably other proteins also play a role in the control of urinary crystal growth.

Calcium Oxalate↗
PubMed1993

A new approach to studying inhibitors of calcium oxalate crystal growth.

The nucleation and crystal growth of calcium oxalate (CaOx) were studied at pH 5.5 using turbidimetric measurements at 620 nm of suspensions produced by mixing calcium chloride and sodium oxalate (initial conditions: Ca, 3 x 10(-3) M; Ox, 0.5 x 10(-3) M). CaOx crystallization kinetics were defined first by the induction time ti and then by the slope of turbidity as a function of time during the interval corresponding to a correlation coefficient r2 > 0.99. The technique described requires only a small amount of material, is quick, convenient, and can be used to study inhibitors of CaOx crystallization by comparing ti and the rate of crystal growth in the presence and absence of inhibitors. The effects on CaOx crystal growth of several low molecular weight compounds, i.e. di- and tricarboxylic acids, were examined. The majority of these compounds were inhibitors of crystal growth, the greatest effect being seen with citric acid (50% inhibition in the presence of 1.5 x 10(-3) M citric acid), isocitric acid (50% inhibition in the presence of 0.75 x 10(-3) M isocitric acid) and pyrophosphate (30% inhibition in presence of 0.15 x 10(-3) M pyrophosphate). The inhibitors' behaviour regarding the medium was studied without any assumptions about their possible mechanisms of action. Measurements of ionized calcium before and after the reaction, as well as the observation of crystals by scanning electron microscopy, allowed us to formulate the hypothesis that the effect of citric acid and tartaric acid can be attributed mainly to ion pairing, in contrast to that of pyrophosphate and the other carboxylic acids.

Calcium↗
PubMed1993

Glaphenine-containing gallstones.

Glaphenine is an analgesic drug derived from anthranilic acid. We report the analytical procedures for stone analysis in three cases of common bile duct stones containing glaphenic acid, which developed in arthrosic patients treated for 13.7 +/- 5 years with glaphenine. Stone analysis was performed by infrared spectroscopy, high performance thin layer chromatography, scanning electron microscopy and energy dispersive X-ray analysis. Mechanisms of lithogenesis are discussed. These observations emphasize the possibility of radiolucent gallstones mainly composed of drug compounds.

Aged↗
PubMed1993

[A silica urinary calculus secondary to the absorption of gelopectose in a child].

The authors report a case of silica-containing urinary stones in a child. This drug-induced urinary stone was secondary to absorption of Gelopectose and its composition was confirmed by infrared spectrophotometry. Other cases have been diagnosed but have not yet been published. Patients with such urinary stones should be investigated for possible hypercalciuria or a disorder of H+ metabolism in the context of distal tubular acidosis, which may be incomplete and/or transient.

Feeding Behavior↗
PubMed1993

[Renal lithostathine: a new protein inhibitor of lithogenesis].

Lithostathine is a protein of pancreatic secretion inhibiting calcium carbonate crystal growth. Antibodies to lithostathine were used to identify a related protein in urine and kidney stones. Western blot analysis of proteins extracted from concentrated normal urine or kidney stones demonstrated the presence of a protein with an apparent molecular weight of 23 kDa. The same antibodies were used in immunolocalization experiments on fresh human nephrectomy specimens cryosections. A positive signal was observed in the cells of proximal tubules and thick ascending limbs of Henle's loop. Protein extracts of renal stones inhibited calcium carbonate crystal growth. Because of its structural and functional similarities with pancreatic lithostathine, it was called renal lithostathine.

Animals↗
PubMed1993

[Correlation between protein and sodium intake and calciuria in calcium lithiasis].

In order to assess the influence of dietary protein and salt intake on urinary calcium excretion in calcium stone formers, we simultaneously determined 24 hour urinary excretion of Urea (UU) and sodium (UNa) together with that of calcium (UCa) in 184 patients (112 males) with idiopathic calcium nephrolithiasis studied on free diet. Mean (+/- SEM) values expressed as mmol/kg BW/day of both UU and UNa were higher in hypercalciuric (UCa > or = 0.1 mmol/kg/d, mean 0.15 +/- 0.01) male patients, respectively 6.63 +/- 0.25 and 2.71 +/- 0.13, than in normocalciuric males, respectively 5.33 +/- 0.22 (p < 0.001) and 2.36 +/- 0.15 (p = 0.06), while the latter did not differ from healthy controls. Similar findings were made in female stone formers. Linear regression analysis on the whole series showed a positive but weak correlation between UU and UCa (r = 0.47, p < 0.001) and between UNa and UC a (r = 0.33, p < 0.001), but the slope of the relation UCa/UU was increased only in hypercalciurics, whereas it did not differ between normocalciurics and controls. By multiple regression analysis, variations of UU and UNa altogether accounted only for 22% of variation in UCa. We conclude that in both sexes hypercalciuric stone formers have a higher protein and sodium intake than normocalciurics, and for a given urinary urea output, their mean urinary calcium excretion is higher, thus suggesting that hypercalciuric stone formers are electively sensitive to the hypercalciuric effect of high protein intake.

Adult↗
PubMed1993

Urinary calculi: review of classification methods and correlations with etiology.

Current physical and chemical methods available for urinary stones analysis are critically reviewed. No one method is sufficient to provide all the clinically useful information on the structure and composition of the stones. We show that a combination of refined morphological and structural examination of stone with optical microscopy, complemented by compositional analysis using infrared spectroscopy of the core, cross-section and surface of calculi, provides a precise and reliable method for identifying the structure and crystalline composition, and permits quantification of stone components while being highly cost effective. Using such morphoconstitutional studies leads to a classification of urinary stones in seven distinctive types and twenty-one subtypes among monohydrate (whewellite) and dihydrate (weddellite) calcium oxalates, phosphates, uric acid, urates, protein, and cystine calculi. Furthermore, all of the recognized sub-types exhibit correlations with specific pathophysiologic conditions. We conclude that such morphoconstitutional refined analysis and classification of urinary calculi is of interest to properly identify the type of stone disease and provides clues to etiopathogeny.

Calcium Oxalate↗
PubMed1992

Urolithiasis in patients with end stage renal failure.

Renal stones from 30 chronic hemodialysis patients were subjected to morphological study by means of microscopic examination and to constitutional analysis with infrared spectrophotometry. In 29 patients calculi could be classified into 3 main types: 1) protein stones made of pure proteins or with a protein core and less than 30% calcium oxalate (9 cases, or 30%)--they were observed predominantly in patients with primary glomerular disease, 2) oxalo-protein stones with a core of calcium oxalate and a total stone content of more than 30% calcium oxalate (15 cases, or 50%)--they appeared to be related to metabolic factors, such as high urinary oxalate and low urinary citrate concentration, and to iatrogenic factors, namely vitamin D3 and calcium salt supplementation, and 3) aluminum-magnesium urate stones, probably induced by aluminum overload (6 cases, or 20%). Thus, our study indicates that a significant proportion (70%) of stones formed by hemodialysis patients may be due to metabolic and iatrogenic factors. Our data suggest that accurate analysis of such stones provides useful information on pathogenetic factors and consequently may give clues to their prophylaxis.

Adult↗
PubMed1992

Evidence that human kidney produces a protein similar to lithostathine, the pancreatic inhibitor of CaCO3 crystal growth.

Pancreatic juice is supersaturated in calcium carbonate. CaCO3 crystal growth is controlled by lithostathine, a secretory protein synthesized by pancreatic acinar cells, first described as a constituent of pancreatic stones. It was recently reported that, in the thin descending limb of the Henle's loop, urine was supersaturated in CaCO3 (Coe FL, Parks JH: Defenses of an unstable compromise: crystallization inhibitors and the kidney's role in mineral regulation. Kidney Int. 1990: 38, 625-631. This observation suggested the presence in kidney of a similar inhibitor. In this study, we show that a protein immunologically related to lithostathine is actually present in urine of healthy subjects and in renal stones. Immunocytochemistry of kidney sections localized the protein to cells of the proximal tubules and thick ascending limbs of the Henle's loops. Protein extracts of renal stones inhibited CaCO3 crystal growth in vitro and this inhibition was significantly lifted by incubating the extracts with antibodies to lithostathine. The protein is not immunologically related to nephrocalcin. Because of its structural and functional similarities with pancreatic lithostathine, it was called renal lithostathine.

Calcium Carbonate↗
PubMed1992

[Composition of urinary calculi defined with precision by infrared spectrophotometry].

In order to reduce the relapse of the disease lithiasis, it is very important to have a very good idea about the growth process of the urinary stone. The greatest concern is the recuperation and the profound analysis of the nucleus and the peripheral layers. The preceding morphological study of the stone fragments in combination with the infrared spectrometry is the only manner to know all about the urinary calculus. Many information is lost if only an overall infrared spectrum of the sample is taken.

Calcium Oxalate↗
PubMed1992

Identification of urinary calculi by Raman laser fiber optics spectroscopy.

Human calculi of various compositions were automatically identified by using near-infrared excitation Fourier-transform Raman spectrometry. After having built a 150-compound Raman library as a first step, we used a commercial software for infrared spectra (program BIRSY, from Brüker) to determine the composition of different calculi. Good results were obtained for both classical Raman laser and Raman laser fiber optics spectroscopies. With the use of a natural biological medium, e.g., urine, to mimic as closely as possible clinical in vivo conditions, the automatic search correctly identified the calculus composition with relatively good test quality; in some mixtures, however, the results can only be considered semi-quantitative at present, even after smoothing of the spectra.

Fiber Optic Technology↗
PubMed1991

[Idiopathic hypercalciuria. Biological studies and therapeutic applications].

Idiopathic hypercalciuria (IHC) is defined by an urinary calcium excretion greater than or equal to 0.10 mmol/kg body weight/day on a free diet in the absence of hypercalcemia. Pak's classification into absorptive and renal forms of IHC is no longer accepted as such. The now proposed "operational" classification of IHC separates dietary IHC, where calcium excretion falls below 0.07 mmol/kg BW/day on moderate dietary calcium restriction, from true IHC, where urinary calcium excretion remains above this value while on a 600 mg Ca diet, with renal and absorptive "presentations". Etiopathogenic mechanisms of IHC are revisited and appear to be multifactorial. They involve endogenous factors, such as disorders of calcitriol biosynthesis (or receptors), bone resorption and/or calcium membrane transport, whose phenotypic expression is enhanced by extrinsic factors, mainly nutritional, such as high animal protein and salt intake. A protocol of laboratory investigation based on these recent data is proposed, together with a stepped therapeutic approach involving a readjustment of nutritional habits combined, when needed, with thiazide diuretics.

Calcium↗